Natal and breeding philopatry of female Steller sea lions in southeastern Alaska.

PubMed

Hastings, Kelly K; Jemison, Lauri A; Pendleton, Grey W; Raum-Suryan, Kimberly L; Pitcher, Kenneth W

2017-01-01

Information on drivers of dispersal is critical for wildlife conservation but is rare for long-lived marine mammal species with large geographic ranges. We fit multi-state mark-recapture models to resighting data of 369 known-aged Steller sea lion (Eumetopias jubatus) females marked as pups on their natal rookeries in southeastern Alaska from 1994-2005 and monitored from 2001-15. We estimated probabilities of females being first observed parous at their natal site (natal philopatry), and of not moving breeding sites among years (breeding philopatry) at large (> 400 km, all five rookeries in southeastern Alaska) and small (< 4 km, all islands within the largest rookery, Forrester Island Complex, F) spatial scales. At the rookery scale, natal philopatry was moderately high (0.776-0.859) for most rookeries and breeding philopatry was nearly 1, with < 3% of females switching breeding rookeries between years. At more populous islands at F, natal philopatry was 0.500-0.684 versus 0.295-0.437 at less populous islands, and breeding philopatry was 0.919-0.926 versus 0.604-0.858. At both spatial scales, the probability of pupping at a non-natal site increased with population size of, and declined with distance from, the destination site. Natal philopatry of < 1 would increase gene flow, improve population resilience, and promote population recovery after decline in a heterogeneous environment. Very high breeding philopatry suggests that familiarity with neighboring females and knowledge of the breeding site (the topography of pupping sites and nearby foraging locations) may be a critical component to reproductive strategies of sea lions.

Effects of alternatives to clearcutting on invertebrate and organic detritus transport from headwaters in southeastern Alaska.

Treesearch

Jake Musslewhite; Mark S. Wipfli

2004-01-01

We examined the transport of invertebrates and coarse organic detritus from headwater streams draining timber harvest units in a selective timber harvesting study, alternatives to clearcutting (ATC) in southeastern Alaska. Transport in 17 small streams (mean measured discharge range: 1.2 to 14.6 L/s) was sampled with 250- µ m-mesh drift nets in spring, summer, and fall...

CDOM Optical Properties and Connectivity in the Western Gulf of Alaska, the Unimak Pass and the Southeastern Bering Sea in the Spring During a Cold Year

NASA Astrophysics Data System (ADS)

D'Sa, E. J.; Goes, J. I.; Mouw, C. B.

2016-02-01

Flow through the Aleutian Passes connects the North Pacific to the Bering Sea with the Unimak Pass forming an important conduit for the flow of Gulf of Alaska water to the southeastern Bering shelf. While the biophysical properties have been studied for this region, little is known about the dissolved organic matter (DOM) and its optically active chromophoric component (CDOM) which play key roles in ocean color and several biogeochemical and photochemical processes. Dissolved organic carbon (DOC), and CDOM absorption and fluorescence properties were measured at locations in the western Gulf of Alaska, Unimak Pass and the southeastern Bering Sea in spring 2012, a relatively cold year as indicated by hydrographic field and satellite sea surface temperature data. DOC concentrations were on average higher in the western Gulf of Alaska (112.21 ± 20.05 µM) and Unimak Pass (106.14 ± 16.10 µM), than the southeastern Bering Sea shelf (73.28 ± 11.71 µM) suggesting Gulf of Alaska shelf water to be an important source of DOM to the eastern Bering Sea. Overall, CDOM absorption was relatively low while parallel factor (PARAFAC) analysis of DOM fluorescence identified two humic-like (terrestrial and marine) and one protein-like (tryptophan-like) component in the DOM pool. Relationships between the DOM optical properties and the physical regime will be further examined in this study.

ISEA (International geodetic project in SouthEastern Alaska) for rapid uplifting caused by glacial retreat: (4) Gravity tide observation

NASA Astrophysics Data System (ADS)

Sato, T.; Miura, S.; Sun, W.; Kaufman, A. M.; Cross, R.; Freymueller, J. T.; Heavner, M.

2006-12-01

The southeastern Alaska shows a large uplift rate as 30 mm/yr at most, which is considered to be closely related to the glacial isostatic adjustment (GIA) including two effects of the past and present-day ice melting (Larsen et al., 2004). So, this area is important to improve our knowledge of the viscoelastic property of the earth and to consider the global changes. Combing the displacement and gravity observations is useful to constrain the model computation results for GIA (Sato et al., 2006). In order to progress the previous work by the group of Univ. Alaska, Fairbanks (UAF), an observation project by Japan and USA groups was started in 2005 (Miura et al., this meeting). Under this project, June 2006, the continuous GPS measurements started (M. Kufman et al., this meeting) and the absolute gravity (AG) measurements were conducted (W. Sun et al., this meeting). Precise correction for the effect of ocean tide loading is one of the key to increase the observation accuracy of the GPS and gravity observations, especially for the AG measurement. Thanks for the satellite sea surface altimeters such as TOPEX/Poseidon and Jason-1, the accuracy of global ocean tide models based on these data has been much improved, and its accuracy is estimated at a level better than 1.3 cm as a RMS error of the vector differences of the 8 main tidal waves (Matsumoto et al., 2006). However, on the other hand, it is known that the southeastern Alaska is a place that shows a large discrepancy among the proposed global ocean tide models mainly due to a complex topography and bathymetry of the fjord area. In order to improve the accuracy of the ocean tide correction, we started the gravity tide observation at Juneau from June 2006. Two kinds of gravimeters are used for the observation. Sampling interval of the data is at every 1 min. We analyzed the 1 month data from the beginning of the observation and compared the tidal analysis results with the model tide including both effects of the solid and ocean tides. For this computation, we used the Love numbers and the loading Green function for the PREM earth model (Dziewonski & Anderson, 1981) and a global ocean tide model by Schwiderski (1980). Our comparison clearly indicates that a possibility to improve the accuracy of the model prediction by taking into account the actual tidal harmonics observed in the southeastern Alaska.

Natal and breeding philopatry of female Steller sea lions in southeastern Alaska

PubMed Central

2017-01-01

Information on drivers of dispersal is critical for wildlife conservation but is rare for long-lived marine mammal species with large geographic ranges. We fit multi-state mark-recapture models to resighting data of 369 known-aged Steller sea lion (Eumetopias jubatus) females marked as pups on their natal rookeries in southeastern Alaska from 1994–2005 and monitored from 2001–15. We estimated probabilities of females being first observed parous at their natal site (natal philopatry), and of not moving breeding sites among years (breeding philopatry) at large (> 400 km, all five rookeries in southeastern Alaska) and small (< 4 km, all islands within the largest rookery, Forrester Island Complex, F) spatial scales. At the rookery scale, natal philopatry was moderately high (0.776–0.859) for most rookeries and breeding philopatry was nearly 1, with < 3% of females switching breeding rookeries between years. At more populous islands at F, natal philopatry was 0.500–0.684 versus 0.295–0.437 at less populous islands, and breeding philopatry was 0.919–0.926 versus 0.604–0.858. At both spatial scales, the probability of pupping at a non-natal site increased with population size of, and declined with distance from, the destination site. Natal philopatry of < 1 would increase gene flow, improve population resilience, and promote population recovery after decline in a heterogeneous environment. Very high breeding philopatry suggests that familiarity with neighboring females and knowledge of the breeding site (the topography of pupping sites and nearby foraging locations) may be a critical component to reproductive strategies of sea lions. PMID:28591130

Malaspina Glacier, Alaska

NASA Image and Video Library

2003-05-01

Malaspina Glacier in southeastern Alaska is considered the classic example of a piedmont glacier. Piedmont glaciers occur where valley glaciers exit a mountain range onto broad lowlands, are no longer laterally confined, and spread to become wide lobes.

Petrology, composition, and age of intrusive rocks associated with the Quartz Hill molybdenite deposit, southeastern Alaska.

USGS Publications Warehouse

Hudson, T.; Smith, James G.; Elliott, R.L.

1979-01-01

A large porphyry molybdenum deposit (Quartz Hill deposit) was recently discovered in the heart of the Coast Range batholithic complex about 70 km E of Ketchikan, SE Alaska. Intrusive rocks associated with the mineral deposit form two composite epizonal to hypabyssal stocks and many dikes in country rocks. All observed metallization and alteration is within the Quartz Hill stock. Molybdenite forms fracture coatings and occurs in veins with quartz. Alteration is widespread and includes development of secondary quartz, pyrite, K-feldspar, biotite, white mica, chlorite, and zeolite. Field relations indicate that the stocks were emplaced after regional uplift and erosion of the Coast Range batholithic complex, and K-Ar data show that intrusion and alteration took place in late Oligocene time, about 27 to 30 Ma ago. Data from the Ketchikan quadrangle indicate that porphyry molybdenum metallization in the Coast Range batholithic complex is associated with regionally extensive but spotty, middle Tertiary or younger, felsic magmatism. -from Authors

The forest ecosystem of southeast Alaska: 3. Fish habitats.

Treesearch

William R. Meehan

1974-01-01

The effects of logging and associated activities on fish habitat in southeastern Alaska are discussed, and fish habitat research applicable to southeast Alaska is summarized. Requirements of salmonids for suitable spawning and rearing areas are presented. Factors associated with timber harvest which may influence these habitats are discussed in detail; e.g., sediment,...

Gravity measurements in southeastern Alaska reveal negative gravity rate of change caused by glacial isostatic adjustment

NASA Astrophysics Data System (ADS)

Sun, W.; Miura, S.; Sato, T.; Sugano, T.; Freymueller, J.; Kaufman, M.; Larsen, C. F.; Cross, R.; Inazu, D.

2010-12-01

For the past 300 years, southeastern Alaska has undergone rapid ice-melting and land uplift attributable to global warming. Corresponding crustal deformation (3 cm/yr) caused by the Little Ice Age retreat is detectable with modern geodetic techniques such as GPS and tidal gauge measurements. Geodetic deformation provides useful information for assessing ice-melting rates, global warming effects, and subcrustal viscosity. Nevertheless, integrated geodetic observations, including gravity measurements, are important. To detect crustal deformation caused by glacial isostatic adjustment and to elucidate the viscosity structure in southeastern Alaska, Japanese and U.S. researchers began a joint 3-year project in 2006 using GPS, Earth tide, and absolute gravity measurements. A new absolute gravity network was established, comprising five sites around Glacier Bay, near Juneau, Alaska. This paper reports the network's gravity measurements during 2006-2008. The bad ocean model in this area hindered ocean loading correction: Large tidal residuals remain in the observations. Accurate tidal correction necessitated on-site tidal observation. Results show high observation precision for all five stations: <1 μGal. The gravity rate of change was found to be -3.5 to -5.6 μGal/yr in the gravity network. Furthermore, gravity results obtained during the 3 years indicate a similar gravity change rate. These gravity data are anticipated for application in geophysical studies of southeastern Alaska. Using gravity and vertical displacement data, we constructed a quantity to remove viscoelastic effects. The observations are thus useful to constrain present-day ice thickness changes. A gravity bias of about -13.2 ± 0.1 mGal exists between the Potsdam and current FG5 gravity data.

A Decade of Shear-Wave Splitting Observations in Alaska

NASA Astrophysics Data System (ADS)

Bellesiles, A. K.; Christensen, D. H.; Abers, G. A.; Hansen, R. A.; Pavlis, G. L.; Song, X.

2010-12-01

Over the last decade four PASSCAL experiments have been conducted in different regions of Alaska. ARCTIC, BEAAR and MOOS form a north-south transect across the state, from the Arctic Ocean to Price Williams Sound, while the STEEP experiment is currently deployed to the east of that line in the St Elias Mountains of Southeastern Alaska. Shear-wave splitting observations from these networks in addition to several permanent stations of the Alaska Earthquake Information Center were determined in an attempt to understand mantle flow under Alaska in a variety of different geologic settings. Results show two dominant splitting patterns in Alaska, separated by the subducted Pacific Plate. North of the subducted Pacific Plate fast directions are parallel to the trench (along strike of the subducted Pacific Plate) indicating large scale mantle flow in the northeast-southwest direction with higher anisotropy (splitting times) within the mantle wedge. Within or below the Pacific Plate fast directions are normal to the trench in the direction of Pacific Plate convergence. In addition to these two prominent splitting patterns there are several regions that do not match either of these trends. These more complex regions which include the results from STEEP could be due to several factors including effects from the edge of the Pacific Plate. The increase of station coverage that Earthscope will bring to Alaska will aid in developing a more complete model for anisotropy and mantle flow in Alaska.

25 CFR 241.4 - Subsistence and sport fishing, Annette Islands Reserve.

Code of Federal Regulations, 2013 CFR

2013-04-01

... of Fish and Game for Commercial Fishing in Fishing District No. 1. Sport fishing within the Annette... regulation for Southeastern Alaska by the Alaska Board of Fish and Game. Both subsistence and sport fishing...

Downed woody material in southeast Alaska forest stands.

Treesearch

Frederic R. Larson

1992-01-01

Data collected in conjunction with the multiresource inventory of southeast Alaska in 1985-86 included downed wood along 234 transects at 60 locations. Transects occurred in 11 forest types and 19 plant associations within the entire southeastern Alaska archipelago. Downed wood weights in forest types ranged from 1232 kilograms per hectare (0.6 ton per acre) in muskeg...

Case study comparison of two pellet heating facilities in southeastern Alaska

Treesearch

David Nicholls; Allen Brackley; Robert Deering; Daniel Parrent; Brian Kleinhenz; Craig. Moore

2016-01-01

Over the past decade, wood-energy use in Alaska has grown dramatically. Since 2000, several dozen new wood-energy installations have been established, with numerous others in the design or construction phase. This case study report compares two wood-pellet heating systems in Juneau, Alaska. The Tlingit-Haida Regional Housing Authority, a native housing authority that...

Earthquakes in Alaska

USGS Publications Warehouse

Haeussler, Peter J.; Plafker, George

1995-01-01

Earthquake risk is high in much of the southern half of Alaska, but it is not the same everywhere. This map shows the overall geologic setting in Alaska that produces earthquakes. The Pacific plate (darker blue) is sliding northwestward past southeastern Alaska and then dives beneath the North American plate (light blue, green, and brown) in southern Alaska, the Alaska Peninsula, and the Aleutian Islands. Most earthquakes are produced where these two plates come into contact and slide past each other. Major earthquakes also occur throughout much of interior Alaska as a result of collision of a piece of crust with the southern margin.

Phylogeography of brown bears (Ursus arctos) of Alaska and paraphyly within the Ursidae.

PubMed

Talbot, S L; Shields, G F

1996-06-01

Complete nucleotide sequences of the mitochondrial cytochrome b, tRNA(prolime), and tRNA(threonine) genes were described for 166 brown bears (Ursus arctos) from 10 geographic regions of Alaska to describe natural genetic variation, construct a molecular phylogeny, and evaluate classical taxonomies. DNA sequences of brown bears were compared to homologous sequences of the polar bear (maritimus) and of the sun bear (Helarctos malayanus), which was used as an outgroup. Parsimony and neighbor-joining methods each produced essentially identical phylogenetic trees that suggest two distinct clades of mtDNA for brown bears in Alaska: one composed only of bears that now reside on some of the islands of southeastern Alaska and the other which includes bears from all other regions of Alaska. The very close relationship of the polar bear to brown bears of the islands of southeastern Alaska as previously reported by us and the paraphyletic association of polar bears to brown bears reported by others have been reaffirmed with this much larger data set. A weak correlation is suggested between types of mtDNA and habitat preference by brown bears in Alaska. Our mtDNA data support some, but not all, of the currently designated subspecies of brown bears whose descriptions have been based essentially on morphology.

Ordovician "sphinctozoan" sponges from Prince of Wales Island, southeastern Alaska

USGS Publications Warehouse

Rigby, J.K.; Karl, Susan M.; Blodgett, R.B.; Baichtal, J.F.

2005-01-01

A faunule of silicified hypercalcified "sphinctozoan" sponges has been recovered from a clast of Upper Ordovician limestone out of the Early Devonian Karheen Formation on Prince of Wales Island in southeastern Alaska. Included in the faunule are abundant examples of the new genus Girtyocoeliana, represented by Girtyocoeliana epiporata (Rigby and Potter), and Corymbospongia adnata Rigby and Potter, along with rare Corymbospongia amplia n. sp., and Girtyocoelia(?) sp., plus common Amblysiphonella sp. 1 and rare Amblysiphonella(?) sp. 2. The assemblage is similar to that from Ordovician clasts from the eastern Klamath Mountains of northern California. This indicates that the Alexander terrane of southeastern Alaska is related paleogeographically to the lithologically and paleontologically similar terrane of the eastern Klamath Mountains. This lithology and fossil assemblage of the clast cannot be tied to any currently known local rock units on Prince of Wales Island. Other clasts in the conglomerate appear to have been locally derived, so it is inferred that the limestone clasts were also locally derived, indicating the presence of a previously undocumented Ordovician limestone unit on northern Prince of Wales Island. 

Estimating annual high-flow statistics and monthly and seasonal low-flow statistics for ungaged sites on streams in Alaska and conterminous basins in Canada

USGS Publications Warehouse

Wiley, Jeffrey B.; Curran, Janet H.

2003-01-01

Methods for estimating daily mean flow-duration statistics for seven regions in Alaska and low-flow frequencies for one region, southeastern Alaska, were developed from daily mean discharges for streamflow-gaging stations in Alaska and conterminous basins in Canada. The 15-, 10-, 9-, 8-, 7-, 6-, 5-, 4-, 3-, 2-, and 1-percent duration flows were computed for the October-through-September water year for 222 stations in Alaska and conterminous basins in Canada. The 98-, 95-, 90-, 85-, 80-, 70-, 60-, and 50-percent duration flows were computed for the individual months of July, August, and September for 226 stations in Alaska and conterminous basins in Canada. The 98-, 95-, 90-, 85-, 80-, 70-, 60-, and 50-percent duration flows were computed for the season July-through-September for 65 stations in southeastern Alaska. The 7-day, 10-year and 7-day, 2-year low-flow frequencies for the season July-through-September were computed for 65 stations for most of southeastern Alaska. Low-flow analyses were limited to particular months or seasons in order to omit winter low flows, when ice effects reduce the quality of the records and validity of statistical assumptions. Regression equations for estimating the selected high-flow and low-flow statistics for the selected months and seasons for ungaged sites were developed from an ordinary-least-squares regression model using basin characteristics as independent variables. Drainage area and precipitation were significant explanatory variables for high flows, and drainage area, precipitation, mean basin elevation, and area of glaciers were significant explanatory variables for low flows. The estimating equations can be used at ungaged sites in Alaska and conterminous basins in Canada where streamflow regulation, streamflow diversion, urbanization, and natural damming and releasing of water do not affect the streamflow data for the given month or season. Standard errors of estimate ranged from 15 to 56 percent for high-duration flow statistics, 25 to greater than 500 percent for monthly low-duration flow statistics, 32 to 66 percent for seasonal low-duration flow statistics, and 53 to 64 percent for low-flow frequency statistics.

Silurian gastropoda from southeastern and west-central Alaska

USGS Publications Warehouse

Rohr, D.M.; Blodgett, R.B.; Fryda, J.

2008-01-01

Additional Silurian (Ludlovian) gastropods are described from the Heceta Formation in the Alexander terrane on Prince of Wales Island, southeastern Alaska. Species include Spinicharybdis krizi n. sp., Spinicharybdis boucoti n. sp., Morania wagneri n. sp., Haplospira craigi n. sp., Australonema sp., Pachystrophia cf. gotlandica (Lindstro??m, 1884), and Medfrazyga gilmulli n. sp. An additional new Silurian species, Morania nixonforkensis n. sp., is described from the Nixon Fork subterrane of the Farewell terrane of west-central Alaska. The spine-bearing Spinicharybdis is placed into a new subfamily Spinicharybdiinae together with Hystricoceras Jahn, 1894. Joint occurrences of genera Beraunia, Coelocaulus, and Morania, as well as members of subfamily Spinicharybdiinae in the gastropod fauna from the Heceta Formation, support its close relationship with gastropod fauna of Bohemia. Additionally, the occurrence of the genus Medfrazyga suggests a faunal link between the Alexander and Farewell terranes of Alaska. Medfrazyga gilmulli n. sp. is the oldest known and the only early Paleozoic member of the family Palaeozygopleuridae. Copyright ?? 2008, The Paleontological Society.

Seismicity of the Earth 1900-2013 offshore British Columbia-southeastern Alaska and vicinity

USGS Publications Warehouse

Hayes, Gavin P.; Smoczyk, Gregory M.; Ooms, Jonathan G.; McNamara, Daniel E.; Furlong, Kevin P.; Benz, Harley M.; Villaseñor, Antonio

2014-01-01

The tectonics of the Pacific margin of North America between Vancouver Island and south-central Alaska are dominated by the northwest motion of the Pacific plate with respect to the North America plate at a velocity of approximately 50 mm/yr. In the south of this mapped region, convergence between the northern extent of the Juan de Fuca plate (also known as the Explorer microplate) and North America plate dominate. North from the Explorer, Pacific, and North America plate triple junction, Pacific:North America motion is accommodated along the ~650-km-long Queen Charlotte fault system. Offshore of Haida Gwaii and to the southwest, the obliquity of the Pacific:North America plate motion vector creates a transpressional regime, and a complex mixture of strike-slip and convergent (underthrusting) tectonics. North of the Haida Gwaii islands, plate motion is roughly parallel to the plate boundary, resulting in almost pure dextral strike-slip motion along the Queen Charlotte fault. To the north, the Queen Charlotte fault splits into multiple structures, continuing offshore of southwestern Alaska as the Fairweather fault, and branching east into the Chatham Strait and Denali faults through the interior of Alaska. The plate boundary north and west of the Fairweather fault ultimately continues as the Alaska-Aleutians subduction zone, where Pacific plate lithosphere subducts beneath the North America plate at the Aleutians Trench. The transition is complex, and involves intraplate structures such as the Transition fault. The Pacific margin offshore British Columbia is one of the most active seismic zones in North America and has hosted a number of large earthquakes historically.

Reconnaissance engineering geology of the Petersburg area, southeastern Alaska, with emphasis on geologic hazards

USGS Publications Warehouse

Yehle, Lynn A.

1978-01-01

A program to study the engineering geology of most larger Alaska coastal communities and to evaluate their earthquake and other geologic hazards was started following the 1964 Alaska earthquake; this report about the Petersburg area is a product of that program. Field-study methods were of a reconnaissance nature, and thus, interpretations in the report are tentative. Landscape of the northern end of Mitkof Island on which Petersburg is situated is characterized by a gently sloping, muskeg-covered terrain, with altitudes mostly less than 30 m. In contrast, much of the rest of the island is composed of mountainous terrain with many steep valleys. During the Pleistocene Epoch, the Petersburg area presumably was covered by ice several times; glaciers deeply eroded many valleys on Mitkof Island and adjacent areas. The last major deglaciation probably was largely completed by 12,000 years ago. Delayed rebound of the earth's crust, after the melting of large amounts of ice, permitted extensive inundation of land in the Petersburg area. Subsequently, emergence has elevated marine deposits to a present-day altitude of at least 65 m and probably to 75 m. Bedrock in the Petersburg map area is composed of relatively hard metamorphic rocks, chiefly phyllite and probably some graywacke. Rocks are of Middle(?) Jurassic to Early Cretaceous age. Five types of surficial geologic material of Quaternary age were recognized: (1) mixed deposits consisting of diamicton, silt-clay, and sand or sandy pebble gravel, (2) alluvial deposits, (3) shore and delta deposits, (4) organic deposits, and (5) artificial fill. Geologic structure in southeastern Alaska is complex because several cycles of tectonic deformation since at least early Paelozoic time have affected different parts of the region. The latest of the major tectonic events in southeastern Alaska occurred in Tertiary time, with some minor activity continuing into the Quaternary Period. Along the outer coast of southeastern Alaska, active strike-slip movement is occurring along the Chichagof-Baranof and Queen Charlotte faults. A segment of the prominent Coast-Range lineament, part of which may be a fault, lies 18 km northeast of Petersburg. Many earthquakes occur along the outer coast of southeastern Alaska. Most of these shocks are associated with movements along the Chichagof-Baranof, Queen Charlotte, and Transition faults. A few small earthquakes occur in the region between the outer coast and the southern part of the Coast Mountains. 0nly a few earthquakes have been recorded as felt at Petersburg; these shocks and others possibly felt in the Petersburg region are tabulated. Among the recorded earthquakes the highest intensity (about V-VI) as the magnitude 7.1 earthquake of October 24, 1927, that occurred probably along the Chichagof-Baranof fault, and about 225 km northwest of Petersburg; damage was reported as minor. Other large earthquakes along the Chichagof-Baranof fault that affected or probably affected the Petersburg area in a minor way occurred on August 22, 1949 (magnitude 8.1) and on July 30, 1972 (magnitude 7.25). From a consideration of the tectonics and earthquake history of the region, earthquakes similar to the 1927, 1949, and 1972 shocks are expected to recur on segments of the Chichagof-Baranof or Queen Charlotte faults. The closest of these fault segments is about 170 km southwest from Petersburg. The likelihood of destructive earthquakes being generated along faults closer to Petersburg is unknown. A very generalized discussion of possible geologic effects that could occur in the area during a postulated, theoretically reasonable worst case earthquake of magnitude 8 occurring along the outer coast about 170 km southwest from Petersburg notes that ground shaking probably would be strongest on organic deposits and least on bedrock and on firm, compact diamicton. Among other effects that could happen are: (1) liquefaction of some of the few delta and alluvial

Origin of Silurian reefs in the Alexander Terrane of southeastern Alaska

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soja, C.M.

1991-04-01

Lower to Upper Silurian (upper Llandovery-Ludlow) limestones belonging to the Heceta Formation record several episodes of reef growth in the Alexander terrane of southeastern Alaska. As the oldest carbonates of wide-spread distribution in the region, the Heceta limestones represent the earliest development of a shallow-marine platform within the Alexander arc and the oldest foundation for reef evolution. These deposits provide important insights into the dynamic processes, styles, and bathymetry associated with reef growth in tectonically active oceanic islands. Massive stromatoporoids, corals, and red algae are preserved in fragmental rudstones and represent a fringing reef that formed at the seaward edgemore » of the incipient marine shelf. Accessory constituents in this reef include crinoids and the cyanobacterium Girvanella. Small biostromes were constructed by ramose corals and stromatoporoids on oncolitic substrates in backreef or lagoonal environments. These buildups were associated with low-diversity assemblages of brachiopods and with gastropods, amphiporids, calcareous algae and cyanobacteria. Microbial boundstones reflect the widespread encrustation of cyanobacteria and calcified microproblematica on shelly debris as stromatolitic mats that resulted in the development of a stromatactoid-bearing mud mound and a barrier reef complex. Epiphytaceans, other microbes, and aphrosalpingid sponges were the primary frame-builders of the barrier reefs. These buildups attained significant relief at the shelf margin and shed detritus as slumped blocks and debris flows into deep-water sites along the slope. The similarity of these stromatolitic-aphrosalpingid reefs to those from Siluro-Devonian strata of autochthonous southwestern Alaska suggests paleobiogeographic ties of the Alexander terrane to cratonal North America during the Silurian.« less

GLACIER BAY NATIONAL MONUMENT WILDERNESS STUDY AREA, ALASKA.

USGS Publications Warehouse

Brew, David A.; Kimball, Arthur L.

1984-01-01

Glacier Bay National Monument is a highly scenic and highly mineralized area about 100 mi west of Juneau, Alaska. Four deposits with demonstrated resources of nickel, copper, zinc, and molybdenum have been identified within the monument and eleven areas of probable or substantiated mineral-resource potential have been identified. The monument is highly mineralized in comparison with most areas of similar size elsewhere in southeastern Alaska, and present estimates of mineral resources are considered conservative.

Geologic Map of Baranof Island, southeastern Alaska

USGS Publications Warehouse

Karl, Susan M.; Haeussler, Peter J.; Himmelberg, Glen R.; Zumsteg, Cathy L.; Layer, Paul W.; Friedman, Richard M.; Roeske, Sarah M.; Snee, Lawrence W.

2015-01-01

This map updates the geology of Baranof Island based on fieldwork, petrographic analyses, paleontologic ages, and isotopic ages. These new data provide constraints on depositional and metamorphic ages of lithostratigraphic rock units and the timing of structures that separate them. Kinematic analyses and thermobarometric calculations provide insights on the regional tectonic processes that affected the rocks on Baranof Island. The rocks on Baranof Island are components of a Paleozoic to Early Tertiary oceanic volcanic arc complex, including sedimentary and volcanic rocks that were deposited on and adjacent to the arc complex, deformed, and accreted. The arc complex consists of greenschist to amphibolite facies Paleozoic metavolcanic and metasedimentary rocks overlain by lower-grade Triassic metasedimentary and metavolcanic rocks and intruded by Jurassic calc-alkaline plutons. The Paleozoic rocks correlate well in age and lithology with rocks of the Sicker and Buttle Lake Groups of the Wrangellia terrane on Vancouver Island and differ from rocks of the Skolai Group that constitute basement to type-Wrangellia in the Wrangell Mountains. The Jurassic intrusive rocks are correlative with plutons that intrude the Wrangellia terrane on Vancouver Island but are lacking in the Wrangell Mountains. The rocks accreted beneath the arc complex are referred to as the Baranof Accretionary Complex in this report and are correlated with the Chugach Accretionary Complex of southern and southeastern Alaska and with the Pacific Rim Complex on Vancouver Island. Stratigraphic correlations between upper- and lower-plate rocks on Baranof Island and western Chichagof Island with rocks on Haida Gwaii and Vancouver Island, in addition to correlative ages of intrusive rocks and restorations of the Fairweather-Queen Charlotte, Chatham Strait, and Peril Strait Faults that define the Baranof-Chichagof block, suggest Baranof Island was near Vancouver Island at the time of initiation of arc magmatism in the Early Jurassic. Early Eocene plutons that intruded the accretionary complex outboard of the arc on Baranof Island are attributed to anatectic melting of trench sediments resulting from subduction of a spreading center. Oligocene intrusive rocks on Baranof Island correlate in age and composition with intrusive rocks in the Kano Plutonic Suite on Haida Gwaii, and similar magmatic sources are inferred.

Headwater riparian invertebrate communities associated with red alder and conifer wood and leaf litter in southeastern Alaska

USGS Publications Warehouse

LeSage, C.M.; Merritt, R.W.; Wipfli, M.S.

2005-01-01

We examined how management of young upland forests in southeastern Alaska affect riparian invertebrate taxa richness, density, and biomass, in turn, potentially influencing food abundance for fish and wildlife. Southeastern Alaska forests are dominated by coniferous trees including Sitka spruce (Picea sitchensis (Bong.) Carr.), western hemlock (Tsuga heterophylla (Raf.) Sarg.), with mixed stands of red cedar (Thuja plicata Donn.). Red alder (Alnus rubra Bong.) is hypothesized to influence the productivity of young-growth conifer forests and through forest management may provide increased riparian invertebrate abundance. To compare and contrast invertebrate densities between coniferous and alder riparian habitats, leaf litter and wood debris (early and late decay classes) samples were collected along eleven headwater streams on Prince of Wales Island, Alaska, during the summers of 2000 and 2001. Members of Acarina and Collembola were the most abundant taxa collected in leaf litter with alder litter having significantly higher mean taxa richness than conifer litter. Members of Acarina were the most abundant group collected on wood debris and alder wood had significantly higher mean taxa richness and biomass than conifer wood. Alder wood debris in more advanced decay stages had the highest mean taxa richness and biomass, compared to other wood types, while conifer late decay wood debris had the highest densities of invertebrates. The inclusion of alder in young-growth conifer forests can benefit forest ecosystems by enhancing taxa richness and biomass of riparian forest invertebrates. ?? 2005 by the Northwest Scientific Association. All rights reserved.

Geochemistry and mineralogy of the Dotson Zone HREE deposit in the Bokan Mountain peralkaline igneous complex, southeastern Alaska, USA

USGS Publications Warehouse

Taylor, Cliff D.; Lowers, Heather; Adams, David; Robinson, R. James

2017-01-01

The Bokan Mountain igneous complex (BMIC) is a typical example of a peralkaline intrusive system that has evolved to the point of developing late stage HFSE- and REE-rich silicic pegmatites and dikes. The Dotson Zone comprises a series of felsic dikes that extend from the southeast margin of the composite pluton and may represent an important resource of critical HREEs. Petrographically, the primary igneous mineral assemblage is altered by late-igneous and hydrothermal fluids resulting in redistribution and enrichment of REEs. An area of flexure in the southeastern end of the Dotson Zone was the primary locus of enrichment as shown by the pervasive alteration and consistently high REE+Y values. We favor a model in which the dikes were emplaced concurrently with the marginal intrusions, and then altered during emplacement of the inner, main intrusion in a relatively rapid series of overlapping intrusive and late magmatic fluid-high temperature hydrothermal events as the complex cooled. A much later sodic intrusive event focused on the BMIC may have resulted in additional silica-Na-Zr-rich alteration in proximity to the pluton.

Correlates of microhabitat use and density of Clethrionomys gapperi and Peromyscus keeni in temperate rain forests of Southeast Alaska.

Treesearch

Winston P. Smith; Scott M. Gende; Jeffrey V. Nichols

2005-01-01

We studied red-backed vole Clethrionomys gapperi and Keen' s mouse Peromyscus keeni populations in the Alexander Archipelago to test predictions regarding habitat relations in temperate rain forest of southeastern Alaska during August - September 1998 and 2000 and April - May 1999 and 2000. We measured 26 vegetative and...

Needs and Opportunities: An Exploratory Needs Assessment Survey for University of Alaska, Juneau.

ERIC Educational Resources Information Center

Johnson, B. Lamar

The University of Alaska (UAJ) consists of Juneau-Douglas Community College and Southeastern Senior College. Enrollment is predominantly part-time and largely concentrated in the community college. Personal interviews were conducted in May-June 1979 with 16 UAJ personnel and 50 citizens in six adjacent communities to identify local and University…

Seasonal use of small tributary and main-stem habitats by juvenile steelhead, coho salmon, and Dolly Varden in a southeastern Alaska drainage basin.

Treesearch

R.G. Bramblett; M.D. Bryant; B.E. Wright; R.G. White

2002-01-01

The movement of juvenile salmonids between small tributaries and main-stem habitats in southeast Alaska watersheds is poorly understood. We observed movements of steelhead Oncorhynchus mykiss, coho salmon O. kisutch, and Dolly Varden Salvelinus malma between mainstem and tributary habitats at weirs located...

High-resolution multi-channel seismic images of the Queen Charlotte Fault system offshore southeastern Alaska

NASA Astrophysics Data System (ADS)

Miller, N. C.; Brothers, D. S.; Kluesner, J.; Balster-Gee, A.; Ten Brink, U. S.; Andrews, B. D.; Haeussler, P. J.; Watt, J. T.; Dartnell, P.; East, A. E.

2016-12-01

We present high-resolution multi-channel seismic (MCS) images of fault structure and sedimentary stratigraphy along the southeastern Alaska margin, where the northern Queen Charlotte Fault (QCF) cuts the shelf-edge and slope. The QCF is a dominantly strike slip system that forms the boundary between the Pacific (PA) and North American (NA) plates offshore western Canada and southeastern Alaska. The data were collected using a 64 channel, 200 m digital streamer and a 0.75-3 kJ sparker source aboard the R/V Norseman in August 2016. The survey was designed to cross a seafloor fault trace recently imaged by multibeam sonar (see adjacent poster by Brothers et al.) and to extend the subsurface information landward and seaward from the fault. Analysis of these MCS and multibeam data focus on addressing key questions that have significant implications for the kinematic and geodynamic history of the fault, including: Is the imaged surface fault in multibeam sonar the only recently-active fault trace? What is the shallow fault zone width and structure, is the internal structure of the recently-discovered pull-apart basin a dynamically developing structure? How does sediment thickness vary along the margin and how does this variation affect the fault expression? Can previous glacial sequences be identified in the stratigraphy?

Protolith relations of the Gravina belt and Yukon-Tanana terrane in central southeastern Alaska

DOE Office of Scientific and Technical Information (OSTI.GOV)

McClelland, W.C.; Gehrels, G.E.; Patchett, P.J.

1992-01-01

Metamorphic rocks west of the Coast Mountains batholith in central southeastern Alaska are divided into the Gravina belt, Taku terrane, and newly defined Ruth assemblage. The Ruth assemblage comprises metapelite, quartzose metaclastic strata, quartzite, marble, felsic metatuff, mafic metavolcanic rocks, and orthogneiss. Depositional and emplacement ages of 367 {plus minus} 10 Ma and 345 {plus minus} 13 Ma inferred from discordant U/Pb zircon analyses on felsic metatuff and granodioritic orthogneiss, respectively, require that at least portions of the Ruth assemblage be Late Devonian and early Mississippian in age. The assemblage is similar in age and protolith to, and thus correlatedmore » with, the Yukon-Tanana terrane. The Gravina belt is characterized by upper Jurassic and lower Cretaceous mafic volcanic rocks and tuffaceous turbiditic clastic strata that unconformably overlie the Alexander terrane. Metamorphic rocks that structurally underlie the Taku terrane and Rugh assemblage are included in this assemblage. Trace element geochemistry and the abundance of pyroclastic flows associated with tuffaceous turbidites suggest that the Gravina belt evolved in an intra-arc basinal setting. In central southeastern Alaska, the mid-Cretaceous structure that currently separates the Ruth assemblage (Yukon-Tanana correlative) from the Gravina belt marks the fundamental boundary between the Alexander-Wrangellia terrane and inboard Yukon-Tanana and Stikine terranes.« less

The study of the undiscovered mineral resources of the Tongass National Forest and adjacent lands, Southeastern Alaska

USGS Publications Warehouse

Brew, D.A.; Drew, L.J.; Ludington, S.D.

1992-01-01

The quantitative probabilistic assessment of the undiscovered mineral resources of the 17.1-million-acre Tongass National Forest (the largest in the United States) and its adjacent lands is a nonaggregated, mineral-resource-tract-oriented assessment designed for land-planning purposes. As such, it includes the renewed use of gross-in-place values (GIPV's) in dollars of the estimated amounts of metal contained in the undiscovered resources as a measure for land-use planning. Southeastern Alaska is geologically complex and contains a wide variety of known mineral deposits, some of which have produced important amounts of metals during the past 100 years. Regional geological, economic geological, geochemical, geophysical, and mineral exploration history information for the region was integrated to define 124 tracts likely to contain undiscovered mineral resources. Some tracts were judged to contain more than one type of mineral deposit. Each type of deposit may contain one or more metallic elements of economic interest. For tracts where information was sufficient, the minimum number of as-yet-undiscovered deposits of each type was estimated at probability levels of 0.95, 0.90, 0.50, 0.10, and 0.05. The undiscovered mineral resources of the individual tracts were estimated using the U.S. Geological Survey's MARK3 mineral-resource endowment simulator; those estimates were used to calculate GIPV's for the individual tracts. Those GIPV's were aggregated to estimate the value of the undiscovered mineral resources of southeastern Alaska. The aggregated GIPV of the estimates is $40.9 billion. Analysis of this study indicates that (1) there is only a crude positive correlation between the size of individual tracts and their mean GIPV's: and (2) the number of mineral-deposit types in a tract does not dominate the GIPV's of the tracts, but the inferred presence of synorogenic-synvolcanic nickel-copper, porphyry copper skarn-related, iron skarn, and porphyry copper-molybdenum deposits does. The influence of this study on the U.S. Forest Service planning process is yet to be determined. ?? 1992 Oxford University Press.

Constraints on the age and provenance of the Chugach accretionary complex from detrital zircons in the Sitka Graywacke near Sitka, Alaska

USGS Publications Warehouse

Haeussler, Peter J.; Gehrels, George E.; Karl, Susan M.

2006-01-01

The Sitka Graywacke is the westernmost and youngest unit of the Chugach accretionary complex in southeastern Alaska. Using laser-ablation inductively coupled plasma mass spectroscopy, we obtained 492 detrital-zircon ages on seven typical samples of Sitka Graywacke turbidites, which were collected in a transect across much of the unit near Sitka, Alaska. Individual grains range in age from 66 to 1,802 m.y. The youngest peak ages on relative-probability plots of the western four samples (74, 72, 74, and 74 m.y., from west to east) are distinctly younger than the youngest peak ages of the eastern three samples (105, 103, and 97 m.y., from west to east). These youngest peak ages set maximum depositional ages for each sample. We suggest that these peak ages are not significantly older (within ~5 m.y.) than the depositional age of the Sitka Graywacke because the deposits accumulated in a trench along a convergent margin, where magmatic sources likely continuously introduced juvenile zircons. The differences in the youngest cluster of detrital-zircon ages between the eastern and western sample localities is likely due to both a change in provenance and a fault. The similarity of the youngest peak ages in the Sitka Graywacke to fossil ages in the Valdez Group, in Prince William Sound, implies that the western part of the Sitka Graywacke is correlative with the Valdez Group, as previously inferred. However, the eastern part of the Sitka Graywacke has youngest detrital-zircon ages older than fossil ages in the Valdez Group and younger than fossil ages in the McHugh Complex, which in south-central Alaska is the oldest part of the accretionary complex. The age distribution of zircons in the older, eastern sequence suggests sources along the British Columbia margin. The detrital-zircon ages in the younger, western sequence are similar to igneous ages from south-central Alaska to southern British Columbia. Right-lateral strike slip on various fault systems inboard of the Sitka Graywacke implies that it lay to the south when it was deposited and offscraped. Thus, although source areas as far north as the St. Elias Mountains and south-central Alaska are possible, they were most likely in coastal and interior British Columbia.

Return of salmon-derived nutrients from the riparian zone to the stream during a storm in southeastern Alaska

Treesearch

Jason B. Fellman; Eran Hood; Rick T. Edwards; David V. D' Amore

2008-01-01

Spawning salmon deliver nutrients (salmon-derived nutrients, SDN) to natal watersheds that can be incorporated into terrestrial and aquatic food webs, potentially increasing ecosystem productivity. Peterson Creek, a coastal watershed in southeast Alaska that supports several species of anadromous fish, was sampled over the course of a storm during September 2006 to...

Stratiform zinc-lead mineralization in Nasina assemblage rocks of the Yukon-Tanana Upland in east-central Alaska

USGS Publications Warehouse

Dusel-Bacon, Cynthia; Bressler, Jason R.; Takaoka, Hidetoshi; Mortensen, James K.; Oliver, Douglas H.; Leventhal, Joel S.; Newberry, Rainer J.; Bundtzen, Thomas K.

1998-01-01

The Yukon-Tanana Upland of east-central Alaska and Yukon comprises thrust sheets of ductilely deformed metasedimentary and metaigneous rocks of uncertain age and origin that are overlain by klippen of weakly metamorphosed oceanic rocks of the Seventymile-Slide Mountain terrane, and intruded by post-kinematic Early Jurassic, Cretaceous and Tertiary granitoids. Metamorphosed continental margin strata in the Yukon-Tanana Upland of east-central Alaska are thought to be correlative, on the basis of stratigraphic similarities and sparse Mississippian U-Pb zircon and fossil ages (Mortensen, 1992), with middle Paleozoic metasedimentary and metavolcanic rocks in the eastern Alaska Range and in western and southeastern Yukon. Furthermore, rocks in the northern Yukon-Tanana Upland may correlate across the Tintina fault with unmetamorphosed counterparts in the Selwyn Basin (Murphy and Abbott, 1995). Volcanic-hosted (VMS) and sedimentary exhalative (sedex) massive sulfide occurrences are widely reported for these other areas (green-colored unit of fig. 1) but, as yet, have not been documented in the Alaskan part of the Yukon-Tanana Upland. Recent discoveries of VMS deposits in Devono-Mississippian metavolcanic rocks in the Finlayson Lake area of southeastern Yukon (Hunt, 1997) have increased the potential for finding VMS deposits in rocks of similar lithology and age in the Yukon-Tanana Upland of Alaska. Restoration of 450 km of early Tertiary dextral movement along the Tintina fault juxtaposes these two areas.

Field performance in southeast Alaska of sitka spruce seedlings produced at two nurseries.

Treesearch

John C. Zasada; Peyton W. Owston; Dennis Murphy

1990-01-01

A study of nursery stock performance was conducted on four sites in the Tongass National Forest in southeastern Alaska: two sites at Fire Cove (Ketchikan Ranger District [R.D.]) and one each at Anita Bay (Wrangell R.D.) and Eight Fathom (Hoonah R.D.). Containerized Sitka spruce seedlings used in the study were grown at USDA Forest Service nurseries in Petersburg,...

Report on the Work of the Bureau of Education for the Natives of Alaska, 1915-16. Bulletin, 1917, No. 32

ERIC Educational Resources Information Center

Bureau of Education, Department of the Interior, 1917

1917-01-01

In August 1887, William Duncan, an independent missionary working among the Tsimpsean Indians of British Columbia, brought to Annette Islands, in the southeastern part of Alaska, a colony of between 800 and 1,000 of Indians from the old town of Metlakatla in British Columbia. Under the leadership of Mr. Duncan, this colony made rapid progress. In…

Influence of overstory on snow depth and density in hemlock-spruce stands: implications for management of deer habitat in Southeastern Alaska.

Treesearch

Thomas A. Hanley; Cathy L. Rose

1987-01-01

Snow depth and density were measured in 33 stands of western hemlock-Sitka spruce (Tsuga heterophylla [Rat] Sarg.-Picea sitchensis [Bong.] Carr.) over a 3-year period. The stands, near Juneau, Alaska, provided broad ranges of species composition, age, over-story canopy coverage, tree density, and wood volume. Stepwise multiple regression analyses indicated that both...

Emsian (late Early Devonian) sponges from west-central and south-central Alaska

USGS Publications Warehouse

Rigby, J.K.; Blodgett, R.B.; Anderson, N.K.

2009-01-01

Relatively common specimens of the hypercalcified agelasiid sponge Hormospongia labyrinthica Rigby and Blodgett, 1983 and specimens of associated species of Hormospongia have been previously reported from Emsian and Eifelian stratigraphic units at several localities in south-central and southeastern Alaska (Rigby and Blodgett, 1983). Those sponges were first described from the type section of the Eifelian Cheeneetnuk Limestone in the McGrath A-5 quadrangle. Since then several additional specimens of Hormospongia labyrinthica have also been collected from a new locality in the Talkeetna C-6 quadrangle in southcentral Alaska (Figs. 1, 2.1), and are documented here.

Life and death of the resurrection plate: Evidence for its existence and subduction in the northeastern Pacific in Paleocene-Eocene time

USGS Publications Warehouse

Haeussler, P.J.; Bradley, D.C.; Wells, R.E.; Miller, M.L.

2003-01-01

Onshore evidence suggests that a plate is missing from published reconstructions of the northeastern Pacific Ooean in Paleocene- Eocene time. The Resurrection plate, named for the Resurrection Peninsula ophiolite near Seward, Alaska, was located east of the Kula plate and north of the Farallon plate. We interpret coeval near-trench magmatism in southern Alaska and the Cascadia margin as evidence for two slab windows associated with trench-ridge-trench (TRT) triple junctions, which formed the western and southern boundaries of the Resurrection plate. In Alaska, the Sanak-Baranof belt of near-trench intrusions records a west-to-east migration, from 61 to 50 Ma, of the northern TRT triple junction along a 2100-km-long section of coastline. In Oregon, Washington, and southern Vancouver Island, voluminous basaltic volcanism of the Siletz River Volcanics, Crescent Formation, and Metchosin Volcanics occurred between ca. 66 and 48 Ma. Lack of a clear age progression of magmatism along the Cascadia margin suggests that this southern triple junction did not migrate significantly. Synchronous near-trench magmatism from southeastern Alaska to Puget Sound at ca. 50 Ma documents the middle Eocene subduction of a spreading center, the crest of which was subparallel to the margin. We interpret this ca. 50 Ma event as recording the subduction-zone consumption of the last of the Resurrection plate. The existence and subsequent subduction of the Resurrection plate explains (1) northward terrane transport along the southeastern Alaska-British Columbia margin between 70 and 50 Ma, synchronous with an eastward-migrating triple junction in southern Alaska; (2) rapid uplift and voluminous magmatism in the Coast Mountains of British Columbia prior to 50 Ma related to subduction of buoyant, young oceanic crust of the Resurrection plate; (3) cessation of Coast Mountains magmatism at ca. 50 Ma due to cessation of subduction, (4) primitive mafic magmatism in the Coast Mountains and Cascade Range just after 50 Ma, related to slab-window magmatism, (5) birth of the Queen Charlotte transform margin at ca. 50 Ma, (6) extensional exhumation of high-grade metamorphic terranes and development of core complexes in British Columbia, Idaho, and Washington, and extensional collapse of the Cordilleran foreland fold-and-thrust belt in Alberta, Montana, and Idaho after 50 Ma related to initiation of the transform margin, (7) enigmatic 53-45 Ma magmatism associated with extension from Montana to the Yukon Territory as related to slab breakup and the formation of a slab window, (8) right-lateral margin-parallel strike-slip faulting in southern and western Alaska during Late Cretaceous and Paleocene time, which cannot be explained by Farallon convergence vectors, and (9) simultaneous changes in Pacific-Farallon and Pacific-Kula plate motions concurrent with demise of the Kula-Resurrection Ridge.

Aerial surveys of endangered cetaceans and other marine mammals in the northwestern Gulf of Alaska and southeastern Bering Sea. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brueggeman, J.J.; Green, G.A.; Grotefendt, R.A.

1987-09-01

Aerial surveys were conducted in the Northwestern Gulf of Alaska and southeastern Bering Sea to determine the abundance, distribution, and habitat use patterns of endangered cetaceans and other marine mammals. Four species of cetaceans listed by the Federal Government as endangered were observed: gray, humpback, finback, and sperm whales. Sightings were also made to seven nonendangered species of cetaceans: minke, Cuvier's beaked, Baird's beaked, belukha, and killer whales, and Dall and harbor porpoises. Results show that the project area is an important feeding ground for relatively large numbers of humpback and finback whales and lower numbers of gray whale migrationmore » route between seasonal ranges. The project area also supports a variety of other marine mammals both seasonally and annually.« less

Summary of reconnaissance for radioactive deposits in Alaska, 1945-1954, and an appraisal of Alaskan uranium possibilities

USGS Publications Warehouse

Wedow, Helmuth

1956-01-01

In the period 1945-1954 over 100 investigations for radioactive source materials were made in Alaska. The nature of these investigations ranged from field examinations of individual prospects or the laboratory analysis of significantly radioactive samples submitted by prospectors to reconnaissance studies of large districts. In this period no deposits of uranium or thorium that would warrant commercial exploitation were discovered. The investigations, however, disclosed that radioactive materials occur in widely scattered areas of Alaska and in widely diverse environments. Many igneous rocks throughout Alaska are weakly radioactive because of uranium- and thorium-bearing accessory minerals, such as allanite, apatite, monazite, sphene, xenotime, and zircon; more rarely the radioactivity of these rocks is due to thorianite or thorite and their uranoan varieties. The felsic rocks, for example, granites and syenites, are generally more radioactive than the mafic igneous rocks. Pegmatites, locally, have also proved to be radioactive, but they have little commercial significance. No primary uranium oxide minerals have been found yet in Alaskan vein deposits, except, perhaps, for a mineral tentatively identified as pitchblende in the Hyder district of southeastern Alaska. However, certain occurrences of secondary uranium minerals, chiefly those of the uranite group, on the Seward Peninsula, in the Russian Mountains, and in the vicinity of Kodiak suggest that pitchblende-type ores may occur at depth beneath zones of alteration. Thorite-bearing veins have been discovered on Prince of Wales Island in southeastern Alaska. Although no deposits or carnotite-type minerals have been found in Alaska, several samples containing such minerals have been submitted by Alaskan prospectors. Efforts to locate the deposits from which these minerals were obtained have been unsuccessful, but review of available geologic data suggests that several Alaskan areas are potentially favorable for carnotite-type deposits. The chief of these areas is the Alaska Peninsula-Cook Inlet area which encompasses most of the reported occurrences of the prospectors' carnotite-type samples. Alaska is also potentially favorable for the occurrence of large bodies of the very low-grade uraniferous sedimentary rocks, such as phosphorites and black shales. This type of deposit, however, has not received much study because of the emphasis on the search for bonanza-type high-grade ores. Uraniferous phosphorites similar to those of Idaho, Montana, and Wyoming occur in northern Alaska on the north flank of the Brooks Range; black shales comparable to the uraniferous shales of the Chattanooga formation of southeastern United States have been noted along the Yukon River near the international boundary. Placer deposits in Alaska have some small potential for the production of the radioactive elements as byproducts of gold- and tin-placer mining. the placer area believed to have the relatively greatest potential in Alaska lies in the Kahiltna River valley where concentrates are known to contain such commercial minerals as ilmenite, cassiterite, platinum, and gold in addition to uranothorianite and monazite. The possibilities of the natural fluids--water and petroleum--have not yet been tested in Alaska to any great extent. Studies of fluids are in progress to determine whether they may be used to discover and define areas potentially favorable for the occurrence of uraniferous lodes.

Intrusive rocks and plutonic belts of southeastern Alaska, U.S.A.

USGS Publications Warehouse

Brew, David A.; Morrell, Robert P.; Roddick, J.A.

1983-01-01

About 30 percent of the 175,000-km2 area of southeastern Alaska is underlain by intrusive igneous rocks. Compilation of available information on the distribution, composition, and ages of these rocks indicates the presence of six major and six minor plutonic belts. From west to east, the major belts are: the Fairweather-Baranof belt of early to mid-Tertiary granodiorite; the Muir-Chichagof belt of mid-Cretaceous tonalite and granodiorite; the Admiralty-Revillagigedo belt of porphyritic granodiorite, quartz diorite, and diorite of probable Cretaceous age; the Klukwan-Duke belt of concentrically zoned or Alaskan-type ultramafic-mafic plutons of mid-Cretaceous age within the Admiralty-Revillagigedo belt; the Coast Plutonic Complex sill belt of tonalite of unknown, but perhaps mid-Cretaceous, age; and the Coast Plutonic Complex belt I of early to mid-Tertiary granodiorite and quartz monzonite. The minor belts are distributed as follows: the Glacier Bay belt of Cretaceous and(or) Tertiary granodiorite, tonalite, and quartz diorite lies within the Fair-weather-Baranof belt; layered gabbro complexes of inferred mid-Tertiary age lie within and are probably related to the Fairweather-Baranof belt; the Chilkat-Chichagof belt of Jurassic granodiorite and tonalite lies within the Muir-Chichagof belt; the Sitkoh Bay alkaline, the Kendrick Bay pyroxenite to quartz monzonite, and the Annette and Cape Fox trondhjemite plutons, all interpreted to be of Ordovician(?) age, together form the crude southern southeastern Alaska belt within the Muir-Chichagof belt; the Kuiu-Etolin mid-Tertiary belt of volcanic and plutonic rocks extends from the Muir-Chichagof belt eastward into the Admiralty-Revillagigedo belt; and the Behm Canal belt of mid- to late Tertiary granite lies within and next to Coast Plutonic Complex belt II. In addition, scattered mafic-ultramafic bodies occur within the Fairweather-Baranof, Muir-Chichagof, and Coast Plutonic Complex belts I and II. Palinspastic reconstruction of 200 km of right-lateral movement on the Chatham Strait fault does not significantly change the pattern of the major belts but does bring parts of the minor mid-Tertiary and Ordovician(?) belts closer together. The major belts are related to the stratigraphic-tectonic terranes of Berg, Jones, and Coney (1978) as follows: the Fairweather-Baranof belt is largely in the Chugach, Wrangell (Wrangellia), and Alexander terranes; the Muir-Chichagof belt is in the Alexander and Wrangell terranes; the Admiralty-Revillagigedo belt is in the Gravina and Taku terranes; the Klukwan-Duke belt is in the Gravina, Taku, and Alexander terranes; the Coast Plutonic Complex sill belt is probably between the Taku and Tracy Arm terranes; and the Coast Plutonic Complex belts I and II are in the Tracy Arm and Stikine terranes. Significant metallic-mineral deposits are spatially related to certain of these belts, and some deposits may be genetically related. Gold, copper, and molybdenum occurrences may be related to granodiorites of the Fairweather-Baranof belt. Magmatic copper-nickel deposits occur in the layered gabbro within that belt. The Juneau gold belt, which contains gold, silver, copper, lead, and zinc occurrences, parallels and lies close to the Coast Plutonic Complex sill belt; iron deposits occur in the Klukwan-Duke belt; and porphyry molybdenum deposits occur in the Behm Canal belt. The Muir-Chichagof belt of mid-Cretaceous age and the Admiralty-Revillagigedo belt of probable Cretaceous age are currently interpreted as possible magmatic arcs associated with subduction events. In general, the other belts of intrusive rocks are spatially related to structural discontinuities, but genetic relations, if any, are not yet known. The Coast Plutonic Complex sill belt is probably related to a post-Triassic, pre-early Tertiary suture zone that nearly corresponds to the boundary between the Tracy Arm and Taku terranes. The boundary between the Admiralty-Revillagigedo and Muir-Chichagof belts coincides nearly with the Seymour Canal-Clarence Strait lineament and also is probably a major post-Triassic suture.

Active Tectonics of the Far North Pacific Observed with GPS

NASA Astrophysics Data System (ADS)

Elliott, J.; Freymueller, J. T.; Jiang, Y.; Leonard, L. J.; Hyndman, R. D.; Mazzotti, S.

2017-12-01

The idea that the tectonics of the northeastern Pacific is defined by relatively discrete deformation along the boundary between the Pacific and North American plates has given way to a more complex picture of broad plate boundary zones and distributed deformation. This is due in large part to the Plate Boundary Observatory and several focused GPS studies, which have greatly increased the density of high-quality GPS data throughout the region. We will present an updated GPS velocity field in a consistent reference frame as well as a new, integrated block model that sheds light on regional tectonics and provides improved estimates of motion along faults and their potential seismic hazard. Crustal motions in southern Alaska are strongly influenced by the collision and flat-slab subduction of the Yakutat block along the central Gulf of Alaska margin. In the area nearest to the collisional front, small blocks showing evidence of internal deformation are required. East of the front, block motions show clockwise rotation into the Canadian Cordillera while west of the front there are counterclockwise rotations that extend along the Alaska forearc, suggesting crustal extrusion. Farther from the convergent margin, the crust appears to move as rigid blocks, with uniform motion over large areas. In western Alaska, block motions show a southwesterly rotation into the Bering Sea. Arctic Alaska displays southeasterly motions that gradually transition into easterly motion in Canada. Much of the southeastern Alaska panhandle and coastal British Columbia exhibit northwesterly motions. Although the relative plate motions are mainly accommodated along major faults systems, including the Fairweather-Queen Charlotte transform system, the St. Elias fold-and-thrust belt, the Denali-Totschunda system, and the Alaska-Aleutian subduction zone, a number of other faults accommodate lesser but still significant amounts of motion in the model. These faults include the eastern Denali/Duke River system, the Castle Mountain fault, the western Denali fault, the Kaltag fault, and the Kobuk fault. Based on the expanded GPS data set, locked or partially locked sections of the Alaska subduction zone may extend as far north and east as the eastern Alaska Range.

Silurian sponges and some associated fossils from the Heceta Limestone, Prince of Wales Island, southeastern Alaska

USGS Publications Warehouse

Rigby, J.K.; Rohr, D.M.; Blodgett, R.B.; Britt, B.B.

2008-01-01

A small faunule of hypercalcified agelasiid demosponges has been recovered from outcrops of the Silurian Heceta Formation on Prince of Wales Island in southeastern Alaska. Included are abundant Girtyocoeliana epiporata (Rigby and Potter, 1986), of the Girtyocoeliidae Finks and Rigby, 2004; fragments of Alaskaspongiella laminosa n. gen. and sp., Polyplacospongia nodosa n. gen. and sp., and Monolaminospongia gigantia n. gen. and sp., of the Auriculospongiidae Termier and Termier, 1977, and Cladospongia alaskensis n. gen. and sp., Virgulaspongia uniforma n. gen. and sp., and Stipespongia laminata n. gen. and sp. of the Preperonidellidae Finks and Rigby, 2004. Also included are a few fossils of uncertain taxonomic placement, including Turbospongia biperforata n. gen. and sp., along with a small, chambered, tubular fragment and several porous tubular stems that may be additional poriferans. Some isolated octactine-based heteractinid spicules were also recovered from the etched residues. Copyright ?? 2008, The Paleontological Society.

Soda Creek springs - metamorphic waters in the eastern Alaska Range

USGS Publications Warehouse

Richter, D.H.; Donaldson, D.E.; Lamarre, R.A.

1973-01-01

The Soda Creek springs are a group of small, cold mineral springs on the southern flank of the eastern Alaska Range. The spring waters contain anomalous concentrations of carbon dioxide, sodium, chlorine, sulfate, boron, and ammonia and are actively precipitating deposits of calcite and aragonite. Sparingly present in these deposits are mixed-layer illite-montmorillonite clays and zeolite minerals. Low-temperaturemetamorphic reactions in subjacent marine sedimentary rocks of Jurassic and Cretaceous age may have produced the fluids and silicate minerals. With only a few exceptions, cool bicarbonate-rich springs in Alaska are concentrated south of the Denali fault system in south-central Alaska, southeastern Alaska, and along the Kaltag-Tintina fault system. These areas are characterized by active or recently activetectonism, major faults and folds, and an abundance of marine sedimentary rocks.

Reconnaissance for radioactive deposits in Alaska, 1953

USGS Publications Warehouse

Matzko, John J.; Bates, Robert G.

1955-01-01

During the summer of 1953 the areas investigated for radioactive deposits in Alaska were on Nikolai Creek near Tyonek and on Likes Creek near Seward in south-central Alaska where carnotite-type minerals had been reported; in the headwaters of the Peace River in the eastern part of the Seward Peninsula and at Gold Bench on the South Fork of the Koyukuk River in east-central Alaska, where uranothorianite occurs in places associated with base metal sulfides and hematite; in the vicinity of Port Malmesbury in southeastern Alaska to check a reported occurrence of pitchblende; and, in the Miller House-Circle Hot Springs area of east-central Alaska where geochemical studies were made. No significant lode deposits of radioactive materials were found. However, the placer uranothorianite in the headwaters of the Peace River yet remains as an important lead to bedrock radioactive source materials in Alaska. Tundra cover prevents satisfactory radiometric reconnaissance of the area, and methods of geochemical prospecting such as soil and vegetation sampling may ultimately prove more fruitful in the search for the uranothorianite-sulfide lode source than geophysical methods.

Origin of narrow terranes and adjacent major terranes occurring along the denali fault in the eastern and central alaska range, alaska

USGS Publications Warehouse

Nokleberg, W.J.; Richter, D.H.

2007-01-01

Several narrow terranes occur along the Denali fault in the Eastern and Central Alaska Range in Southern Alaska. These terranes are the Aurora Peak, Cottonwood Creek, Maclaren, Pingston, and Windy terranes, and a terrane of ultramafic and associated rocks. Exterior to the narrow terranes to the south is the majorWrangellia island arc composite terrane, and to the north is the major Yukon Tanana metamorphosed continental margin terrane. Overlying mainly the northern margin of the Wrangellia composite terrane are the Kahiltna overlap assemblage to the west, and the Gravina- Nutzotin-Gambier volcanic-plutonic- sedimentary belt to the east and southeast. The various narrow terranes are interpreted as the result of translation of fragments of larger terranes during two major tectonic events: (1) Late Jurassic to mid-Cretaceous accretion of the Wrangellia island arc composite terrane (or superterrane composed of the Wrangellia, Peninsular, and Alexander terranes) and associated subduction zone complexes; and (2) starting in about the Late Cretaceous, dextral transport of the Wrangellia composite terrane along the Denali fault. These two major tectonic events caused: (1) entrapment of a lens of oceanic lithosphere along the suture belt between the Wrangellia composite terrane and the North American Craton Margin and outboard accreted terranes to form the ultramafic and mafic part of the terrane of ultramafic and associated rocks, (2) subsequent dextral translation along the Denali fault of the terrane of ultramafic and associated rocks, (3) dextral translation along the Denali fault of the Aurora Peak, Cottonwood Creek, and Maclaren and continental margin arc terranes from part of the Coast plutonic-metamorphic complex (Coast-North Cascade plutonic belt) in the southwest Yukon Territory or Southeastern Alaska, (4) dextral translation along the Denali fault of the Pingston passive continental margin from a locus along the North American Continental Margin, and (5) formation and dextral transport along the Denali fault of the m??lange of the Windy terrane from fragments of the Gravina-Nutzotin-Gambier volcanic-plutonic-sedimentary belt and from the North American Continental Margin. Copyright ?? 2007 The Geological Society of America.

Brittle deformation along the Gulf of Alaska margin in response to Paleocene-Eocene triple junction migration: in Sisson

USGS Publications Warehouse

Haeussler, Peter J.; Bradley, Dwight C.; Goldfarb, Richard J.

2003-01-01

A spreading center was subducted diachronously along a 2200 km segment of what is now the Gulf of Alaska margin between 61 and 50 Ma, and left in its wake near-trench intrusions and high-T, low-P metamorphic rocks. Gold-quartz veins and dikes, linked to ridge subduction by geochronological and relative timing evidence, provide a record of brittle deformation during and after passage of the ridge. The gold-quartz veins are typically hosted by faults, and their regional extent indicates there was widespread deformation of the forearc above the slab window at the time of ridge subduction. Considerable variability in the strain pattern was associated with the slab window and the trailing plate. A diffuse network of dextral, sinistral, and normal faults hosted small lode-gold deposits (<50,000 oz) in south-central Alaska, whereas crustal-scale dextral faults in southeastern Alaska are spatially associated with large gold deposits (up to 800,000 oz).We interpret the gold-quartz veins as having formed above an eastward-migrating slab window, where the forearc crust responded to the diminishing influence of the forward subducting plate, the increasing influence of the trailing plate, and the thermal pulse and decreased basal friction from the slab window. In addition, extensional deformation of the forearc resulted from the diverging motions of the two oceanic plates at the margins of the slab window. Factors that complicate interpretations of fault kinematics and near-trench dike orientations include a change in plate motions at ca. 52 Ma, northward translation of the accretionary complex, oroclinal bending of the south-central Alaska margin, and subduction of transform segments. We find the pattern of syn-ridge subduction faulting in southern Alaska is remarkably similar to brittle faults near the Chile triple junction and to earthquake focal mechanisms in the Woodlark basin - the two modern sites of ridge subduction. Therefore, extensional and strike-slip deformation above slab windows may be a common occurrence.

The role of red alder in riparian forest structure along headwater streams in southeastern Alaska

USGS Publications Warehouse

Orlikowska, E.H.; Deal, R.L.; Hennon, P.E.; Wipfli, M.S.

2004-01-01

We assessed the influence of red alder on tree species composition, stand density, tree size distribution, tree mortality, and potential for producing large conifers, in 38-42 yr old riparian forests along 13 headwater streams in the Maybeso and Harris watersheds on Prince of Wales Island, Alaska. Red alder ranged from 0 to 53% of the total live basal area of the stands. Tree density, basal area of live and dead trees, and mean diameter of live conifers were not significantly related to the percent of alder as a proportion of total stand live basal area within these riparian forests. The mean diameter of the 100 largest conifers per hectare (the largest trees) was similar among different sites and appeared unrelated to the amount of alder in the stands. The mean diameter of dead conifers increased slightly with increasing proportion of red alder. Most dead trees were small and died standing. Red alder was much more concentrated immediately along stream margins (within 0-1 m distance from the stream bank vs. > 1 m). The presence of red alder did not inhibit the production of large-diameter conifers, and both alder and conifers provided small woody debris for fishless headwater streams in southeastern Alaska. Red alder is an important structural component of young-growth riparian stands.

The Alaska Mineral Resource Assessment Program; guide to information about the geology and mineral resources of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska

USGS Publications Warehouse

Berg, Henry C.

1982-01-01

The Ketchikan and Prince Rupert 1-degree by 2-degree quadrangles, which encompass about 16,000 km2 at the south tip of southeastern Alaska, have been investigated by integrated field and laboratory studies in the disciplines of geology, geochemistry, geophysics, and Landsat data interpretation to determine their mineral-resource potential. Mineral deposits in the study area have been mined or prospected intermittently since about 1900, and production of small tonnages of ores containing gold, silver, copper, lead, zinc, and tungsten has been recorded. Extensive exploration and development currently (1981) is underway at a molybdenum prospect about 65 km east of Ketchikan. Our mineral-resource assessment indicates that the area contains potentially significant amounts of those metallic commodities, as well as of molybdenum, iron, antimony, and barite. The results of these studies have been published in a folio of maps accompanied by descriptive texts, diagrams, tables, and pertinent references. The present report serves as a guide to these investigations, provides relevant background information, and integrates the component maps and reports. It also describes revisions to the geology based on studies completed since the folio was published and includes a list of specific and general references on the geology and mineral deposits of the study area.

A heat-flow reconnaissance of southeastern Alaska.

USGS Publications Warehouse

Sass, J.H.; Lawver, L.A.; Munroe, R.J.

1985-01-01

Heat flow was measured at nine sites in crystalline and sedimentary rocks of SE Alaska. Seven of the sites, located between 115 and 155 km landward of the Queen Charlotte-Fairweather transform fault, have heat flows significantly higher than the mean in the coastal provinces between Cape Mendocino and the Queen Charlotte Islands, and lower than the mean for 81 values within 100 km of the San Andreas transform fault, even further S. There is no evidence for heat sources that might be associated with late Cainozoic thermal events.-P.Br.

Metamorphism within the Chugach accretionary complex on southern Baranof Island, southeastern Alaska

USGS Publications Warehouse

Zumsteg, Cathy L.; Himmelberg, Glen R.; Karl, Susan M.; Haeussler, Peter J.

2003-01-01

On Baranof Island, southeastern Alaska, we identify four metamorphic events that affect rocks associated with the Chugach accretionary complex. This study focuses on the M1 and M4 metamorphic events. Mesozoic schists, gneisses, and migmatitic gneisses exposed near the Kasnyku pluton on central Baranof Island represent the M1 metamorphic rocks. These rocks underwent amphibolite facies metamorphism. Calculated temperatures and pressures range from about 620 to 780 ºC and 5.5 to 6.6 kbar and are compatible with the observed metamorphic mineral assemblages.The M4 metamorphism affected rocks of the Sitka Graywacke on southern Baranof Island, producing extensive biotite and garnet zones as well as andalusite and sillimanite zones at the contacts of the Crawfish Inlet and Redfish Bay plutons. Calculated M4 temperatures and pressures from the andalusite and sillimanite zones range from 575 to 755 ºC and 3.4 to 6.9 kbar. These results fall within the sillimanite stability field, at pressures higher than andalusite stability. These results may indicate the M4 metamorphic event occurred along a P-T path along which the equilibration of aluminosilicate-garnet-plagioclase-quartz did not occur or was not maintained. This interpretation is supported by the occurrence of andalusite and sillimanite within the same sample. We propose the data reflect a clockwise P-T path with peak M4 metamorphism of the sillimanite-bearing samples adjacent to the intrusions at an approximate depth of 15 to 20 km, followed by rapid uplift without reequilibration of garnet-plagioclase-aluminosilicate-quartz.The large extent of the biotite zone, and possibly the garnet zone, suggests that an additional heat source must have existed to regionally metamorphose these rocks during the M4 event. We suggest the M4 regional thermal metamorphism and intrusion of the Crawfish Inlet and Redfish Bay plutons were synchronous and the result of heat flux from a slab window beneath the accretionary complex at that time. If our conclusions regarding the effect of the slab window are correct, the style of metamorphism is different from the Chugach metamorphic complex, which is clearly linked to a slab window. Therefore, our findings would suggest that there is no distinct metamorphic signature for slab window effects.

Thermobarometric constraints on mid-Cretaceous to late Cretaceous metamorphic events in the western metamorphic belt of the Coast Mountains complex near Petersburg, southeastern Alaska

USGS Publications Warehouse

Himmelberg, Glen R.; Brew, David A.

2005-01-01

The western metamorphic belt is part of the Coast Mountains Complex of southeastern Alaska and western Canada. This complex formed as a result of mid-Cretaceous through middle Eocene crustal shortening between the previously amalgamated Wrangellia and Alexander terranes (Insular superterrane) and previously accreted terranes of the North American continental margin (Intermontane superterrane). The western metamorphic belt, which ranges from a few kilometers to several tens of kilometers in width, records a complex sequence of contact-metamorphic and regional metamorphic events, the most significant of which are designated M1R, M2C-R, and M3R. The M1R regional metamorphic event ranged in grade from subgreenschist to greenschist facies and was overprinted by the M2C-R and M3R metamorphic events. The M2C-R metamorphic event is recorded in discrete contact-metamorphic aureoles and regional metamorphic-mineral assemblages related to tonalite-granodiorite plutons of the Admiralty-Revillagigedo plutonic belt. The M3R metamorphic belt, which is adjacent to the M2C-R belt, is characterized by regional Barrovian isograds of garnet, staurolite, kyanite, and sillimanite. Using the THERMOCALC program, pressure-temperature (P-T) conditions for the M2C-R metamorphic event are estimated to be in the ranges 5.3-7.5 kbars and 525-640 deg.C and for the M3R metamorphic event in the ranges 9.4-12.6 kbars and 730-895 deg.C. The M2C-R metamorphic event occurred at approximately 90 Ma, but the timing of the M3R metamorphic event is poorly documented and uncertain. On the basis of an 40Ar/39Ar age on actinolitic amphibole and a Sm-Nd age on garnet core, the timing of metamorphism might be constrained between 90+/-1 and 80+/-9 Ma, although the Sm-Nd age of 80+/-9 m.y. possibly reflects postpeak growth. Thermobarometric data suggest that the two events occurred at different crustal levels and followed different P-T paths. No evidence exists that M2C-R metamorphic-mineral assemblages were overprinted by the M3R metamorphic event, as proposed by some workers. Juxtaposition of the two belts of rocks probably occurred along the Coast shear zone during uplift and exhumation of the Coast Mountains.

NATIONAL COASTAL CONDITION REPORT IV

EPA Science Inventory

The National Coastal Condition Report IV (NCCR IV) is the fourth in a series of environmental assessments of U.S. coastal waters and the Great Lakes. The report includes assessments of all the nation’s estuaries in the contiguous 48 states and Puerto Rico, south-eastern Alaska, ...

More Like Ourselves: Indigenous Capitalism through Tourism

ERIC Educational Resources Information Center

Bunten, Alexis Celeste

2010-01-01

Through a comparison of Indigenous-owned cultural tourism businesses in southeastern Alaska and New Zealand as well as secondary data examining Indigenous tourism across the Pacific, this article introduces the concept of "Indigenous capitalism" as a distinct strategy to achieve ethical, culturally appropriate, and successful Indigenous…

10 CFR 903.23 - Rate extensions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Rate extensions. 903.23 Section 903.23 Energy DEPARTMENT OF ENERGY POWER AND TRANSMISSION RATES Procedures for Public Participation in Power and Transmission Rate Adjustments and Extensions for the Alaska, Southeastern, Southwestern, and Western Area Power...

10 CFR 903.23 - Rate extensions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 4 2014-01-01 2014-01-01 false Rate extensions. 903.23 Section 903.23 Energy DEPARTMENT OF ENERGY POWER AND TRANSMISSION RATES Procedures for Public Participation in Power and Transmission Rate Adjustments and Extensions for the Alaska, Southeastern, Southwestern, and Western Area Power...

10 CFR 903.23 - Rate extensions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 4 2011-01-01 2011-01-01 false Rate extensions. 903.23 Section 903.23 Energy DEPARTMENT OF ENERGY POWER AND TRANSMISSION RATES Procedures for Public Participation in Power and Transmission Rate Adjustments and Extensions for the Alaska, Southeastern, Southwestern, and Western Area Power...

10 CFR 903.23 - Rate extensions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 4 2013-01-01 2013-01-01 false Rate extensions. 903.23 Section 903.23 Energy DEPARTMENT OF ENERGY POWER AND TRANSMISSION RATES Procedures for Public Participation in Power and Transmission Rate Adjustments and Extensions for the Alaska, Southeastern, Southwestern, and Western Area Power...

10 CFR 903.2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... ENERGY POWER AND TRANSMISSION RATES Procedures for Public Participation in Power and Transmission Rate Adjustments and Extensions for the Alaska, Southeastern, Southwestern, and Western Area Power Administrations... less than 1 percent change in the annual revenues of the power system or (2) is for a power system...

10 CFR 903.11 - Advance announcement of rate adjustment.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 903.11 Energy DEPARTMENT OF ENERGY POWER AND TRANSMISSION RATES Procedures for Public Participation in Power and Transmission Rate Adjustments and Extensions for the Alaska, Southeastern, Southwestern, and... advertisement, and/or by Federal Register publication. Written comments relevant to rate policy and design and...

10 CFR 903.11 - Advance announcement of rate adjustment.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 903.11 Energy DEPARTMENT OF ENERGY POWER AND TRANSMISSION RATES Procedures for Public Participation in Power and Transmission Rate Adjustments and Extensions for the Alaska, Southeastern, Southwestern, and... advertisement, and/or by Federal Register publication. Written comments relevant to rate policy and design and...

10 CFR 903.11 - Advance announcement of rate adjustment.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 903.11 Energy DEPARTMENT OF ENERGY POWER AND TRANSMISSION RATES Procedures for Public Participation in Power and Transmission Rate Adjustments and Extensions for the Alaska, Southeastern, Southwestern, and... advertisement, and/or by Federal Register publication. Written comments relevant to rate policy and design and...

10 CFR 903.11 - Advance announcement of rate adjustment.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 903.11 Energy DEPARTMENT OF ENERGY POWER AND TRANSMISSION RATES Procedures for Public Participation in Power and Transmission Rate Adjustments and Extensions for the Alaska, Southeastern, Southwestern, and... advertisement, and/or by Federal Register publication. Written comments relevant to rate policy and design and...

Field guide to the Mesozoic accretionary complex along Turnagain Arm and Kachemak Bay, south-central Alaska

USGS Publications Warehouse

Bradley, Dwight C.; Kusky, Timothy M.; Karl, Susan M.; Haeussler, Peter J.

1997-01-01

Turnagain Arm, just east of Anchorage, provides a readily accessible, world-class cross section through a Mesozoic accretionary wedge. Nearly continuous exposures along the Seward Highway, the Alaska Railroad, and the shoreline of Turnagain Arm display the two main constituent units of the Chugach terrane: the McHugh Complex and Valdez Group. In this paper we describe seven bedrock geology stops along Turnagain Arm, and two others in the Chugach Mountains just to the north (Stops 1-7 and 9), which will be visited as part of the May, 1997 field trip of the Alaska Geological Society. Outcrops along Turnagain Arm have already been described in two excellent guidebook articles (Clark, 1981; Winkler and others 1984), both of which remain as useful and valid today as when first published. Since the early 1980's, studies along Turnagain Arm have addressed radiolarian ages of chert and conodont ages of limestone in the McHugh Complex (Nelson and others, 1986, 1987); geochemistry of basalt in the McHugh Complex (Nelson and Blome, 1991); post-accretion brittle faulting (Bradley and Kusky, 1990; Kusky and others, 1997); and the age and tectonic setting of gold mineralization (Haeussler and others, 1995). Highlights of these newer findings will described both in the text below, and in the stop descriptions.Superb exposures along the southeastern shore of Kachemak Bay show several other features of the McHugh Complex that are either absent or less convincing along Turnagain Arm. While none of these outcrops can be reached via the main road network, they are still reasonably accessible - all are within an hour by motorboat from Homer, seas permitting. Here, we describe seven outcrops along the shore of Kachemak Bay that we studied between 1989 and 1993 during geologic mapping of the Seldovia 1:250,000- scale quadrangle. These outcrops (Stops 61-67) will not be part of the 1997 itinerary, but are included here tor the benefit of those who may wish to visit them later.

Northern goshawk (Accipiter gentilis)

Treesearch

John R. Squires; Richard T. Reynolds

1997-01-01

The Northern Goshawk (hereafter referred to as Goshawk) is a large forest raptor, occupying boreal and temperate forests throughout the Holarctic. In North America, it breeds from Alaska to Newfoundland and south (Fig. 1). This partial migrant winters throughout its breeding range including occasionally the Great Plains and southeastern states; some...

10 CFR 903.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

.... (h) Power Marketing Administration or PMA means the Alaska Power Administration, Southeastern Power... been confirmed, approved, and placed in effect on an interim basis by the Deputy Secretary. (l) Rate... means sales that last for no longer than one year. (p) Substitute Rate means a rate which has been...

10 CFR 903.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

.... (h) Power Marketing Administration or PMA means the Alaska Power Administration, Southeastern Power... been confirmed, approved, and placed in effect on an interim basis by the Deputy Secretary. (l) Rate... means sales that last for no longer than one year. (p) Substitute Rate means a rate which has been...

Haida Months of the Year.

ERIC Educational Resources Information Center

Cogo, Robert

Students are introduced to Haida vocabulary in this booklet which briefly describes the seasons and traditional seasonal activities of Southeastern Alaska Natives. The first section lists the months in English and Haida; e.g., January is "Taan Kungaay," or "Bear Hunting Month." The second section contains seasonal names in…

Reconnaissance engineering geology of the Haines area, Alaska, with emphasis on evaluation of earthquake and other geologic hazards

USGS Publications Warehouse

Lemke, Richard Walter; Yehle, Lynn A.

1972-01-01

The Alaska earthquake of March 27, 1964, brought into sharp focus the need for engineering geologic studies in urban areas. Study of the Haines area constitutes an integral part of an overall program to evaluate earthquake and other geologic hazards in most of the larger Alaska coastal communities. The evaluations of geologic hazards that follow, although based only upon reconnaissance studies and, therefore, subject to revision, will provide broad guidelines useful in city and land-use planning. It is hoped that the knowledge gained will result in new facilities being built in the best possible geologic environments and being designed so as to minimize future loss of life and property damage. Haines, which is in the northern part of southeastern Alaska approximately 75 miles northwest of Juneau, had a population, of about 700 people in 1970. It is built at the northern end of the Chilkat Peninsula and lies within the Coast Mountains of the Pacific Mountain system. The climate is predominantly marine and is characterized by mild winters and cool summers. The mapped area described in this report comprises about 17 square miles of land; deep fiords constitute most of the remaining mapped area that is evaluated in this study. The Haines area was covered by glacier ice at least once and probably several times during the Pleistocene Epoch. The presence of emergent marine deposits, several hundred feet above sea level, demonstrates that the land has been uplifted relative to sea level since the last major deglaciation of the region about 10,000 years ago. The rate of relative uplift of the land at Haines during the past 39 years is 2.26 cm per year. Most or all of this uplift appears to be due to rebound as a result of deglaciation. Both bedrock and surficial deposits are present in the area. Metamorphic and igneous rocks constitute the exposed bedrock. The metamorphic rocks consist of metabasalt of Mesozoic age and pyroxenite of probable early middle Cretaceous age. The igneous rocks consist of diorite and quartz diorite (tonalite) of Cretaceous age. Sedimentary rocks of Tertiary age may be present in the mapped area but are not exposed. The surficial deposits of Quaternary age,-have been divided into the following map units on the basis of time Of deposition, mode of origin, and grain size: (1) undifferentiated drift deposits, (2) outwash and Ice-contact deposits; (3) elevated fine-grained marine deposits, (4) elevated shore and delta deposits, (5) alluvial fan deposits, (6) colluvial deposits, (7) modern beach deposits, (8) Chilkat River flood-plain and delta deposits, and (9) manmade fill. Offshore deposits are described but are not mapped. Southeastern Alaska lies within the tectonically active belt that rims the northern Pacific Basin and has been active since at least early Paleozoic time. The outcrop pattern is the result of late Mesozoic and Tertiary deformational, metamorphic, and intrusive events. Large-scale faulting has been common. The two most prominent inferred fault systems in southeastern Alaska and surrounding regions are: (1) The Denali fault system and (2) the Fairweather-Queen Charlotte Islands fault system. In the general area of Haines, rocks of Mesozoic age northeast of Chilkat River have a simple monoclinal structure. Paleozoic-Mesozoic rocks southwest of Chilkat River are gently to rather complexly folded. Several major and numerous minor faults probably transect the general area of Haines but their exact location and character can only be inferred because their traces are coincident to the long axes of fiords and river valleys, where they are concealed by water or by valley-floor deposits. Inferred faults in or near the Haines mapped area are: (1) Chilkat River fault, (2) Chilkoot fault, (3) Takhin fault, and (4) faults in the saddle area at Haines. Southeastern Alaska lies in one of the two most seismically active zones in Alaska, a State where 6 percent of the world's shallow earthqua

Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Pacific Northwest)--ghost and blue mud shrimp

USGS Publications Warehouse

Hornig, S.; Sterling, A.; Smith, Styles

1989-01-01

Geographic range: The ghost shrimp is found in intertidal areas along the west coast of North America from Mutiny Bay, Alaska, to the mouth of the Tijuana River, San Diego County, California; MacGinitie (1934) and Ricketts and Calvin (1968) reported finding specimens as far south as El Estuario de Punto Banda, Baja California Norte, Mexico. The blue mud shrimp is found from southeastern Alaska to San Quentin Bay (Bahia de San Quentin) in Baja California Norte. The general distribution of the two species in the Pacific Northwest is identical (Figure 3).

Postglacial vegetation history of the Kachemak Bay area, Cook Inlet, south-central Alaska: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998

USGS Publications Warehouse

Ager, Thomas A.

2000-01-01

Pollen records from two sites on the north shore of Kachemak Bay, south-central Alaska, provide the first radiocarbon-dated histories of postglacial vegetation development for southern Cook Inlet. During the late Wisconsin glacial interval, glaciers covered most of Cook Inlet. Deglaciation of Kachemak Bay began prior to 13,000 yr B.P. Pollen evidence indicates that a pioneering herbaceous tundra began to develop by 12,800 yr B.P., but was soon replaced by a shrub tundra of dwarf birch (Betula), Ericales (Ericaceae and Empetrum) and willows (Salix).By 9,500 yr B.P., a shrub-dominated vegetation of alders (Alnus) and willows, with some deciduous trees (Populus spp.) quickly developed and persisted until late Holocene time. By about 4,000–3,800 yr B.P., spruce trees (Picea glauca and (or) P. mariana) from the interior boreal forests reached the northern Kachemak Bay area from upper Cook Inlet and began to displace the alder-dominated vegetation. A coastal forest of Sitka spruce (Picea sitchensis) began to colonize Kachemak Bay more recently, about 1,650 yr B.P. (minimum age), apparently from sources in Prince William Sound to the east. Where Sitka spruce came into proximity with boreal white spruce (Picea glauca), hybridization occurred, ultimately influencing the spruce forests over a large area of the Kenai Lowland. Some key findings of this study are: (1) the Kachemak Bay-area pollen records do not display persuasive evidence for a “Younger Dryas” cold, dry interval ca. 11,000–10,000 yr B.P. that has been reported from pollen records on Kodiak Island (Gulf of Alaska) and Pleasant Island (southeastern Alaska); (2) at least one species of alder may have survived in refugia in south-central Alaska during the last glacial interval; (3) coastal forests appear to be still migrating west along the coast of south-central Alaska, but their spread northward is being limited by drier, colder winter climates; (4) the mountainous topography of south-central Alaska, coupled with varying degrees of maritime climate influence, create complex patterns of climates and vegetation in the region, in both the past and present.

Dungeness crab, Cancer magister, do not extrude eggs annually in southeastern Alaska: An in situ study

USGS Publications Warehouse

Swiney, K.M.; Shirley, Thomas C.; Taggart, S. James; O'Clair, Charles E.

2003-01-01

The reproductive biology of female Dungeness crabs was studied with crab-pot and dive-transect sampling in five bays within or near Glacier Bay National Park and Preserve, southeastern Alaska, in April and September yearly from 1992 to 1998. A large percentage of nonovigerous, mature females was found in April, a time when females were expected to be brooding eggs that hatch in May and June. Our study examined differences between ovigerous and nonovigerous females collected in April and September samples to corroborate our previous laboratory study in which we found nonannual egg extrusion among Dungeness crabs. Seasonal differences in the catches of ovigerous and nonovigerous females, crab sizes, shell condition, and appendage injury were examined. Additionally, all crabs collected from two bays were tagged beginning in the fall of 1995; tagging was conducted twice annually. Our pot and dive data indicate that females, particularly larger ones, do not extrude eggs annually. Larger females have lower molting probabilities, which limits mating potential and increases reliance on stored sperm. The tagging study confirmed that at least some females do not extrude eggs in one year and then extrude eggs at a later time without molting, thus skipping at least one reproductive season. A reproductive cycle of Dungeness crabs in Alaska is introduced which includes earlier egg extrusion by larger females and nonannual egg extrusion.

Modern and Past Rock Exhumation in the St. Elias Mountains Revealed by Onshore and Offshore Detrital Thermochronology

NASA Astrophysics Data System (ADS)

Enkelmann, E.; Dunn, C. A.; Ridgway, K.; Allen, W. K.

2016-12-01

The St. Elias Mountains in southeastern Alaska provide a natural laboratory to study the interacting processes of tectonics and climate. Because of the high-latitude, coastal geography the surface processes in the St. Elias Mountains are dominated by glacial erosion that varied during late Cenozoic climate shifts. Sediment eroded from the St. Elias Mountains are transported into the Gulf of Alaska by large tidewater glaciers and rivers, where they are deposited on the shelf and in large deep-sea submarine fans. Surface uplift and erosion jointly results in exhumation of deep crustal rocks that has been quantified by thermochronology, revealing spatial variations in exhumation rates across the St. Elias Mountains. We present new thermochronology data (apatite and zircon fission-track ages) from offshore strata derived from boreholes drilled by IODP Expedition 341 in the Gulf of Alaska. This offshore record provides an integrated signal of rock exhumation from the St. Elias and southeast Alaska since 10 Ma. Integrating the offshore data with the existing onshore thermochronology reveals that very rapid exhumation (>2 km/Myr) from 8-10 km depths has been occurring in southeastern Alaska since 11­-10 Ma and thus prior to the onset of glaciation. The majority of our offshore data record the past 1 Myr of deposition related to the Bagley-Bering Glacier and allows assessing the long-standing question of the western limit of extreme exhumation observed at the St. Elias syntaxis in the Seward and Hubbard glacial drainages. The zircon fission-track ages from the Bering sediment reveal small age populations that peak between 15­-9 Ma, suggesting much slower exhumation beneath the Bagley Ice Valley than farther east underneath the Seward and Hubbard glacier. Our results point out the first-order role of tectonics in providing sustained uplift and crustal weakening in the upper plate that than serve as areas for focused exhumation due to secondary erosional/climate processes.

Compatible forest management: background and context.

Treesearch

Richard W. Haynes; Robert A. Monserud; Adelaide C. Johnson

2003-01-01

Let US begin by defining our area of interest: the moist maritime forests of the Pacific Northwest (PNW). Geographically (as shown in Figure 1), this includes western Oregon and Washington (the west side of the Cascade Range, the Coast Range, and the Olympic Mountains), coastal British Columbia (Coast Mountains), and island-dominated southeastern Alaska (as far north...

The Forgotten People: The Relocation and Internment of Aleuts during World War II.

ERIC Educational Resources Information Center

Madden, Ryan

1992-01-01

In a "forgotten" episode of World War II, the Native residents (but not white residents) of the Aleutian Islands were evacuated to southeastern Alaska and were compelled to live for three years in internment camps unfit for human habitation without proper medical treatment, adequate food, or basic human rights. (SV)

Orogenesis, high-T thermal events, and gold vein formation within metamorphic rocks of the Alaskan Cordillera

USGS Publications Warehouse

Goldfarb, R.J.; Snee, L.W.; Pickthorn, W.J.

1993-01-01

Mesothermal, gold-bearing quartz veins are widespread within allochthonous terranes of Alaska that are composed dominantly of greenschist-facies metasedimentary rocks. The most productive lode deposits are concentrated in south-central and southeastern Alaska; small and generally nonproductive gold-bearing veins occur upstream from major placer deposits in interior and northern Alaska. Ore-forming fluids in all areas are consistent with derivation from metamorphic devolatilisation reactions, and a close temporal relationship exists between high-T tectonic deformation, igneous activity, and gold mineralization. Ore fluids were of consistently low salinity, CO2-rich, and had ??18O values of 7 ???-12??? and ??D values between -15??? and -35???. Upper-crustal temperatures within the metamorphosed terranes reached at least 450-500??C before onset of significant gold-forming hydrothermal activity. In southern Alaska, gold deposits formed during latter stages of Tertiary, subduction-related, collisional orogenesis and were often temporally coeval with calc-alkaline magmatism. -from Authors

Reconnaissance engineering geology of the Metlakatla area, Annette Island, Alaska, with emphasis on evaluation of earthquakes and other geologic hazards

USGS Publications Warehouse

Yehle, Lynn A.

1977-01-01

A program to study the engineering geology of most larger Alaska coastal communities and to evaluate their earthquake and other geologic hazards was started following the 1964 Alaska earthquake; this report about the Metlakatla area, Annette Island, is a product of that program. Field-study methods were of a reconnaissance nature, and thus the interpretations in the report are tentative. Landscape of the Metlakatla Peninsula, on which the city of Metlakatla is located, is characterized by a muskeg-covered terrane of very low relief. In contrast, most of the rest of Annette Island is composed of mountainous terrane with steep valleys and numerous lakes. During the Pleistocene Epoch the Metlakatla area was presumably covered by ice several times; glaciers smoothed the present Metlakatla Peninsula and deeply eroded valleys on the rest. of Annette Island. The last major deglaciation was completed probably before 10,000 years ago. Rebound of the earth's crust, believed to be related to glacial melting, has caused land emergence at Metlakatla of at least 50 ft (15 m) and probably more than 200 ft (61 m) relative to present sea level. Bedrock in the Metlakatla area is composed chiefly of hard metamorphic rocks: greenschist and greenstone with minor hornfels and schist. Strike and dip of beds are generally variable and minor offsets are common. Bedrock is of late Paleozoic to early Mesozoic age. Six types of surficial geologic materials of Quaternary age were recognized: firm diamicton, emerged shore, modern shore and delta, and alluvial deposits, very soft muskeg and other organic deposits, and firm to soft artificial fill. A combination map unit is composed of bedrock or diamicton. Geologic structure in southeastern Alaska is complex because, since at least early Paleozoic time, there have been several cycles of tectonic deformation that affected different parts of the region. Southeastern Alaska is transected by numerous faults and possible faults that attest to major movements of the earth's crust. The latest of the major tectonic events in the Metlakatla region occurred in middle Tertiary time; some minor fault activity probably continues today at depth. Along the outer coast of southeastern Alaska and British Columbia, major faulting activity occurs in the form of active, strike-slip movement along the Queen Charlotte fault about 100 mi (160 kin) west-southwest of Metlakatla. Some branching subsidiary faults also may be active, at least one of which may be the Sandspit fault. Many major and smaller earthquakes occur along the outer coast. These shocks are related to movements along the Queen Charlotte fault. A few small earthquakes occur in the region between the outer coast and the Coast Mountains, which includes Metlakatla. 0nly a few earthquakes have been reported as felt at Metlakatla; these shocks and others felt in the region are tabulated. Historically, the closest major earthquake was the magnitude 8.1 Queen Charlotte Islands earthquake of August 22, 1949, which occurred along the Queen Charlotte fault 125 mi (200 km) southwest of Metlakatla. No damage was reported at Metlakatla. The probability of destructive earthquakes affecting Metlakatla is unknown. A consideration of the tectonics and earthquake history of the region, however, suggests that sometime in the future an earthquake with a magnitude of about 8 will occur along that segment of the Queen Charlotte fault nearest to Metlakatla. Smaller earthquakes with magnitudes of 6 or more might occur elsewhere in the Metlakatla region or south-southeastward near Dixon Entrance or Hecate Strait. Several geologic effects that have characterized large earthquakes elsewh6re may be expected to accompany some of the possible major earthquakes that might affect the Metlakatla area in the future. Evaluation of effects indicates that fault displacement and tectonic uplift or subsidence are probably unlikely, and ground shaking in general probably would be strongest

Influence of precommercial thinning and herbicides on understory vegetation of young-growth Sitka spruce forest in southeastern Alaska

Treesearch

Elizabeth C. Cole; Thomas A. Hanley; Michael Newton

2010-01-01

The effects of precommercial thinning on the understory vegetative cover of 16- to 18-year-old spruce-hemlock (Picea sitchensis (Bong.) Carriere--Tsuga heterophylla (Raf.) Sarg.) stands were studied in seven replicate areas over seven growing seasons postthinning. Vegetative cover was analyzed at the class level, but species-...

High salmon density and low discharge create periodic hypoxia in coastal rivers

Treesearch

Christopher J. Sergeant; J. Ryan Bellmore; Casey McConnell; Jonathan W. Moore

2017-01-01

Dissolved oxygen (DO) is essential to the survival of almost all aquatic organisms. Here, we examine the possibility that abundant Pacific salmon (Oncorhynchus spp.) and low streamflow combine to create hypoxic events in coastal rivers. Using high-frequency DO time series from two similar watersheds in southeastern Alaska, we summarize DO regimes...

Is Heterobasidion annosum Poorly Adapted to Incite Disease in Cool, Wet Environments?

Treesearch

Charles G. Shaw III

1989-01-01

An argument is advanced to suggest that infection and damage caused in coniferous forests by Heterobasidion annosum are markedly less severe, and survival of the fungus less common, under cool, wet conditions than in other climates. This premise is supported by the author's incisive insights, experience in southeastern Alaska, and data from this...

An approach to effectiveness monitoring of floodplain channel aquatic habitat: salmonid relationships.

Treesearch

M.D. Bryant; R.T. Edwards; R.D. Woodsmith

2005-01-01

Rivers and streams that support anadromous salmonids are an important part of land management planning in southeastern Alaska and the Pacific Northwest of North America. Land managers and planners require a consistent set of protocols that include both the physical and biological aspects of the stream for effectiveness monitoring procedures to evaluate management...

Relationships between Sitka black-tailed deer and their habitat.

Treesearch

Thomas A. Hanley

1984-01-01

Old-growth, western hemlock-Sitka spruce forest in southeastern Alaska is an important element of the habitat of Sitka black-tailed deer. The conversion of uneven-aged, old-growth forests to even-aged, second-growth forests has generated concern about the future carrying capacity of the habitat for deer, especially where snow accumulation is common on winter ranges....

Trophic linkages between headwater forests and downstream fish habitats: implications for forest and fish management.

Treesearch

Mark S. Wipfli

2005-01-01

This study examined the fluvial transport of invertebrates (aquatic and terrestrial) and coarse organic detritus from forested - headwaters in alternatives-to-clearcutting (ATC) harvest units to aquatic habitats downstream in the coastal mountains of southeastern Alaska. Fifty small streams (mean discharge 2.7 Ls-1, range 0.1-128.1 Ls-...

Maintaining wildlife habitat in southeastern Alaska: implications of new knowledge for forest management and research.

Treesearch

Thomas A. Hanley; Winston P. Smith; Scott M. Gende

2005-01-01

We review results and implications from recent wildlife studies that followed from the 1997 Tongass Land Management Plan (TLMP) and identify information needs and directions for research, development, and application. Sustained population viability of wildlife species was identified as a major issue in the TLMP planning process. Several species were identified as...

Effects of hydraulic roughness on surface textures of gravel-bed rivers

Treesearch

John M. Buffington; David R. Montgomery

1999-01-01

Field studies of forest gravel-bed rivers in northwestern Washington and southeastern Alaska demonstrate that bed-surface grain size is responsive to hydraulic roughness caused by bank irregularities, bars, and wood debris. We evaluate textural response by comparing reach-average median grain size (D50) to that predicted from the total bank-full boundary shear stress (...

Red alder, Alnus rubra, as a potential mitigating factor for wildlife habitat following clearcut logging in southeastern Alaska.

Treesearch

T.A. Hanley; J.C. Barnard

1998-01-01

Within-stand variation in understory species composition and biomass was studied in 16 even-aged stands of mixed red alder-Sitka spruce-western hemlcock (Alnus rubra-Picea sitchensis-Tsuga heterophylla) forest. The sites were upland sites, and the stands were 28-39 years old. We compared understory within...

Emplacement, rapid burial, and exhumation of 90-Ma plutons in southeastern Alaska

USGS Publications Warehouse

Himmelberg, G.R.; Haeussler, Peter J.; Brew, D.A.

2004-01-01

In southeastern Alaska, granodiorite-tonalite plutons of the Admiralty-Revillagigedo belt intruded the Jurassic-Cretaceous Gravina belt along the eastern side of the Alexander terrane around 90 Ma. These plutons postdate some deformation related to a major contractional event between the previously amalgamated Wrangellia and Alexander terranes and the previously accreted terranes of the North American margin. We studied the aureole mineral assemblages of these plutons near Petersburg, Alaska, determined pressure and temperature of equilibration, and examined structures that developed within and adjacent to these plutons. Parallelism of magmatic and submagmatic fabrics with fabrics in the country rock indicates synchroneity of pluton emplacement with regional deformation and suggests that magma transport to higher crustal levels was assisted by regional deformation. Replacement of andalusite by kyanite or sillimanite indicates crustal thickening soon after pluton emplacement. Regional structural analysis indicates the crustal thickening was accomplished by thrust burial. Thermobarometric analyses indicate the aureoles reached near-peak temperatures of 525 to 635 ??C at pressures of 570 to 630 MPa. Consideration of the rate of thermal decay of the aureoles suggests that burial was rapid and occurred at rates around 5 to 8 mm/year. Structural observations indicate there was contractional deformation before, during, and after emplacement of the 90-Ma plutons. Initial exhumation of the Admiralty-Revillagedo belt in the Petersburg area may have occurred along a thrust west of the pluton belt within the Gravina belt. ?? 2004 NRC Canada.

Radiometric age map of southcentral Alaska

USGS Publications Warehouse

Wilson, Frederic H.; Turner, D.L.

1975-01-01

This map includes published, thesis, and open-file radiometric data available to us as of June, 1975. Some dates are not plotted because of inadequate location data in the original references.The map is divided into five sections, based on 1:1,000,000 scale enlargements of the National Atlas maps of Alaska. Within each section (e.g., southeastern Alaska), radiometric dates are plotted and keyed to 1:250,000 scale quadrangles. Accompanying each map section is table 1, listing map numbers and the sample identification numbers used in DGGS Special Report 10: Radiometric Dates from Alaska-A 1975 Compilation”. The reader is referred to Special Report 10 for more complete information on location, rock type, dating method, and literature references for each age entry. A listing of dates in Special Report lo which require correction or deletion is included S table 2. Corrected and additional entries are listed in table 3. The listings in tables 2 and 3 follow the format of Special Report 10. Table 4 is a glossary of abbreviations used for quadrangle name, rock type, mineral dated, and type of dating method used.

Radiometric age map of southwest Alaska

USGS Publications Warehouse

Wilson, Frederic H.; Turner, D.L.

1975-01-01

This map includes published, thesis, and open-file radiometric data available to us as of June, 1975. Some dates are not plotted because of inadequate location data in the original references.The map is divided into five sections, based on 1:1,000,000 scale enlargements of the National Atlas maps of Alaska. Within each section (e.g., southeastern Alaska), radiometric dates are plotted and keyed to 1:250,000 scale quadrangles. Accompanying each map section is table 1, listing map numbers and the sample identification numbers used in DGGS Special Report 10: Radiometric Dates from Alaska-A 1975 Compilation”. The reader is referred to Special Report 10 for more complete information on location, rock type, dating method, and literature references for each age entry. A listing of dates in Special Report lo which require correction or deletion is included S table 2. Corrected and additional entries are listed in table 3. The listings in tables 2 and 3 follow the format of Special Report 10. Table 4 is a glossary of abbreviations used for quadrangle name, rock type, mineral dated, and type of dating method used.

Radiometric age map of southeast Alaska

USGS Publications Warehouse

Wilson, Frederic H.; Turner, D.L.

1975-01-01

This map includes published, thesis, and open-file radiometric data available to us as of June, 1975. Some dates are not plotted because of inadequate location data in the original references.The map is divided into five sections, based on 1:1,000,000 scale enlargements of the National Atlas maps of Alaska. Within each section (e.g., southeastern Alaska), radiometric dates are plotted and keyed to 1:250,000 scale quadrangles. Accompanying each map section is table 1, listing map numbers and the sample identification numbers used in DGGS Special Report 10: Radiometric Dates from Alaska-A 1975 Compilation”. The reader is referred to Special Report 10 for more complete information on location, rock type, dating method, and literature references for each age entry. A listing of dates in Special Report lo which require correction or deletion is included S table 2. Corrected and additional entries are listed in table 3. The listings in tables 2 and 3 follow the format of Special Report 10. Table 4 is a glossary of abbreviations used for quadrangle name, rock type, mineral dated, and type of dating method used.

Radiometric age map of northern Alaska

USGS Publications Warehouse

Wilson, Frederic H.; Turner, D.L.

1975-01-01

This map includes published, thesis, and open-file radiometric data available to us as of June, 1975. Some dates are not plotted because of inadequate location data in the original references.The map is divided into five sections, based on 1:1,000,000 scale enlargements of the National Atlas maps of Alaska. Within each section (e.g., southeastern Alaska), radiometric dates are plotted and keyed to 1:250,000 scale quadrangles. Accompanying each map section is table 1, listing map numbers and the sample identification numbers used in DGGS Special Report 10: Radiometric Dates from Alaska-A 1975 Compilation”. The reader is referred to Special Report 10 for more complete information on location, rock type, dating method, and literature references for each age entry. A listing of dates in Special Report lo which require correction or deletion is included S table 2. Corrected and additional entries are listed in table 3. The listings in tables 2 and 3 follow the format of Special Report 10. Table 4 is a glossary of abbreviations used for quadrangle name, rock type, mineral dated, and type of dating method used.

Alaska Science Center: Providing Timely, Relevant, and Impartial Study of the Landscape, Natural Resources, and Natural Hazards for Alaska and Our Nation

USGS Publications Warehouse

,

2007-01-01

The U.S. Geological Survey (USGS), the Nation's largest water, earth, and biological science and civilian mapping agency, has studied the natural features of Alaska since its earliest geologic expeditions in the 1800s. The USGS Alaska Science Center (ASC), with headquarters in Anchorage, Alaska, studies the complex natural science phenomena of Alaska to provide scientific products and results to a wide variety of partners. The complexity of Alaska's unique landscapes and ecosystems requires USGS expertise from many science disciplines to conduct thorough, integrated research.

Grading options for western hemlock "pulpwood" logs from southeastern Alaska.

Treesearch

David W. Green; Kent A. McDonald; John Dramm; Kenneth Kilborn

Properties and grade yield are estimated for structural lumber produced from No. 3, No. 4, and low-end No. 2 grade western hemlock logs of the type previously used primarily for the production of pulp chips. Estimates are given for production in the Structural Framing, Machine Stress Rating, and Laminating Stock grading systems. The information shows that significant...

Controls on the size and occurrence of pools in coarse-grained forest rivers

Treesearch

John M. Buffington; Thomas E. Lisle; Richard D. Woodsmith; Sue Hilton

2002-01-01

Controls on pool formation are examined in gravel- and cobble-bed rivers in forest mountain drainage basins of northern California, southern Oregon, and southeastern Alaska. We demonstrate that the majority of pools at our study sites are formed by flow obstructions and that pool geometry and frequency largely depend on obstruction characteristics (size, type, and...

The northern flying squirrel as an indicator species of temperate rain forest: test of an hypothesis.

Treesearch

Winston P. Smith; Scott M. Gende; Jeffrey V. Nichols

2005-01-01

Management indicator species (MIS) often are selected because their life history and demographics are thought to reflect a suite of ecosystem conditions that are too difficult or costly to measure directly. The northern flying squirrel (Glaucomys sabrinus) has been proposed as an MIS of temperate rain forest of southeastern Alaska based on previous...

An approach to effectiveness monitoring of floodplain channel aquatic habitat: channel condition assessment.

Treesearch

Richard D. Woodsmith; James R. Noel; Michael L. Dilger

2005-01-01

The condition of aquatic habitat and the health of species dependent on that habitat are issues of significant concern to land management agencies, other organizations, and the public at large in southeastern Alaska, as well as along much of the Pacific coastal region of North America. We develop and test a set of effectiveness monitoring procedures for measuring...

Influence of forest and rangeland management on anadromous fish habitat in Western North America: water transportation and storage of logs.

Treesearch

J.R. Sedell; W.S. Duval

1985-01-01

Environmental effects of water transportation of logs in western North America include the historical driving of logs in rivers and streams, and the current dumping, sorting, transportation, and storage of logs in rivers and estuaries in British Columbia and southeastern Alaska. The historical discussion focuses on habitat losses and volumes of...

Tub Toys Orbit the Pacific Subarctic Gyre

NASA Astrophysics Data System (ADS)

Ebbesmeyer, Curtis C.; Ingraham, W. James; Royer, Thomas C.; Grosch, Chester E.

2007-01-01

In 1992, a cargo container of children's bath toys fell overboard in the middle North Pacific Ocean. Subsequently, 29,000 toys were tracked 4,000 kilometers to southeastern Alaska [Ebbesmeyer and Ingraham, 1994]. The spill's upcoming fifteenth anniversary has prompted an examination of the reports of toys stranded on shorelines around the Subarctic Gyre, a planetary vortex the size of the United States.

Normal Magnetization at ca. 1.5 Ma at Three Sites in Yukon Territory, Canada: The Gilsa Sub-chron?

NASA Astrophysics Data System (ADS)

Froese, D. G.; Westgate, J. A.; Barendregt, R. W.; Villeneuve, M.; Jackson, L. E.; Baker, J.; Enkin, R.; Irving, E.; Hart, C.; Preece, S. J.; Sandhu, A.

2001-12-01

Normally magnetized sediment is associated with Fort Selkirk and Paradise Hill tephras in central Yukon Territory. The Fort Selkirk tephra, sourced in the Wrangell Mountains of southeastern Alaska, is dated by the isothermal plateau fission track method (ITPFT) at 1.48 +/- 0.11 Ma. Fort Selkirk tephra is reversely magnetized, however a normal polarity interval occurs between the tephra and an overlying reversely magnetized basalt flow, dated by the Ar-Ar method, at 1.37 +/- 0.03 Ma. This succession is found at two sites in the Fort Selkirk area. At Paradise Hill, 120 km to the northwest, the Paradise Hill tephra, also sourced in the Wrangell Mountains of southeastern Alaska, has an ITPFT age of 1.54 +/- 0.13 Ma and is normally magnetized. The Paradise Hill and Fort Selkirk normal polarity intervals are certainly older than the Jaramillo (1.07-0.99 Ma) and Cobb Mountain (1.24-1.21 Ma) sub-chrons, and younger than the Olduvai (1.95-1.77 Ma). Our age estimates for this normal interval indicate a more plausible correlation to the Gilsa sub-chron estimated at 1.55 Ma from marine records and 1.6 Ma from Icelandic lavas.

Habitat Suitability Index Models: Western grebe

USGS Publications Warehouse

Short, Henry L.

1984-01-01

The western grebe (Aechmophorus occi denta 1is) "breeds from southeastern Alaska, south-central British Columbia, central Alberta, central Saskatchewan and southwestern Manitoba south to southern Californi a, north-central Utah, southwestern Colorado, southwest~rn and northeastern New Mexico, western Nebraska, northwestern Iowa, and western Minnesota; and locally in Mexico from Chihuahua and Durango south to northern Guerrero, Puebla and San Luis Potosi" (American Ornithologists' Union 1983:10).

The mysterious demise of an ice-age relic: exposing the cause of yellow-cedar decline.

Treesearch

Jonathan Thompson

2007-01-01

For more than a century, yellow-cedar has been inexplicably dying throughout the northern coastal rain forests of the Pacific Northwest. Yellow-cedar mortality has been mapped on more than a half million acres in southeastern Alaska, yet until recently the cause of death was a stubborn mystery. Researchers are hopeful, after several decades of investigation, that they...

Interagency, Intergovernmental Organization, and Nongovernmental Organization Coordination During Joint Operations. Volume 2

DTIC Science & Technology

2006-03-17

energy programs, fossil energy, nuclear energy information, and civilian radioactive waste management; oversight of the power marketing administrations...ADMINISTRATION ALASKA BONNEVILLE SOUTHEASTERN SOUTHWESTERN WESTERN AREA OFFICE OF CIVILIAN RADIOACTIVE WASTE MANAGEMENT ASST SECRETARY ( FOSSIL ENERGY) OFFICE ON...Cutter Service and the Lifesaving Service. The USCG remained in the Department of Treasury until 1967 when it transferred to the Department of

Strain partitioning in southeastern Alaska: Is the Chatham Strait Fault active?

USGS Publications Warehouse

Brothers, Daniel; Elliott, Julie L.; Conrad, James E.; Haeussler, Peter J.; Kluesner, Jared

2018-01-01

A 1200 km-long transform plate boundary passes through southeastern Alaska and northwestern British Columbia and represents one of the most seismically active, but poorly understood continental margins of North America. Although most of the plate motion is accommodated by the right-lateral Queen Charlotte–Fairweather Fault (QCFF) System, which has produced at least six M > 7 earthquakes since 1920, seismic hazard assessments also include the Chatham Strait Fault (CSF) as a potentially active, 400 km-long strike slip fault that cuts northward through southeastern Alaska, connecting with the Eastern Denali Fault. Nearly the entire length of the CSF is submerged beneath Chatham Strait and Lynn Canal and has never been systematically imaged using high-resolution marine geophysical approaches. In this study we present an integrated analysis of new marine seismic reflectiondata acquired across Lynn Canal and tectonic block modeling constrained by data from continuous and campaign GPS sites. Seismic profiles cross the CSF at twelve locations spanning ∼50 km of fault length; they reveal thick (up to 300 m) packages of glaciomarine sedimentary facies emplaced on an unconformity surface that formed during the Last Glacial Maximum (LGM). Localized warping of post-LGM stratigraphy (∼13.9 kyr B.P. to present) appears to correlate with sediment drape on basement topography and current-controlled deposition. There is no evidence for an active fault along the axis of Lynn Canal in the seismic reflection data. Crustal block models constrained by GPS data allow, but do not require, a maximum slip rate of 2–3 mm/yr along the CSF; higher slip rates on the CSF result in significant misfit to GPS data in the surrounding region. Based on the combined marine geophysical and GPS observations, it is plausible that the CSF has not generated resolvable coseismic deformation in the last ∼13 ka and that the modern slip-rate is <1 mm/yr. We propose that models for strain transfer between the QCFF and the Denali Fault, and seismic hazard maps in general, may need to be reevaluated.

Strain partitioning in Southeastern Alaska: Is the Chatham Strait Fault active?

NASA Astrophysics Data System (ADS)

Brothers, Daniel S.; Elliott, Julie L.; Conrad, James E.; Haeussler, Peter J.; Kluesner, Jared W.

2018-01-01

A 1200 km-long transform plate boundary passes through southeastern Alaska and northwestern British Columbia and represents one of the most seismically active, but poorly understood continental margins of North America. Although most of the plate motion is accommodated by the right-lateral Queen Charlotte-Fairweather Fault (QCFF) System, which has produced at least six M > 7 earthquakes since 1920, seismic hazard assessments also include the Chatham Strait Fault (CSF) as a potentially active, 400 km-long strike slip fault that cuts northward through southeastern Alaska, connecting with the Eastern Denali Fault. Nearly the entire length of the CSF is submerged beneath Chatham Strait and Lynn Canal and has never been systematically imaged using high-resolution marine geophysical approaches. In this study we present an integrated analysis of new marine seismic reflection data acquired across Lynn Canal and tectonic block modeling constrained by data from continuous and campaign GPS sites. Seismic profiles cross the CSF at twelve locations spanning ∼50 km of fault length; they reveal thick (up to 300 m) packages of glaciomarine sedimentary facies emplaced on an unconformity surface that formed during the Last Glacial Maximum (LGM). Localized warping of post-LGM stratigraphy (∼13.9 kyr B.P. to present) appears to correlate with sediment drape on basement topography and current-controlled deposition. There is no evidence for an active fault along the axis of Lynn Canal in the seismic reflection data. Crustal block models constrained by GPS data allow, but do not require, a maximum slip rate of 2-3 mm/yr along the CSF; higher slip rates on the CSF result in significant misfit to GPS data in the surrounding region. Based on the combined marine geophysical and GPS observations, it is plausible that the CSF has not generated resolvable coseismic deformation in the last ∼13 ka and that the modern slip-rate is <1 mm/yr. We propose that models for strain transfer between the QCFF and the Denali Fault, and seismic hazard maps in general, may need to be reevaluated.

Alaska Open-File Report 127 Assessment of Thermal Springs Sites in Southern Southeastern Alaska - Preliminary Results and Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Motyka, Roman J.; Moorman, Mary A.; Reeder, John W.

1980-06-01

Information has been gathered on 13 reported thermal-spring sites, 12 in southern Southeastern Alaska and one in western British Columbia. Five of the reported sites could not be substantiated by DGGS. The eight known thermal spring sites are associated with grainitic terrain and, except for Baker Island Hot Springs, occur within or near intensively fractured Cretaceous-age pluons of the Coast Range Batholith. Thermal-spring surface temperatures range from 21 C (Twin Lakes) to 91.5 C (Bailey Bay). The greatest discharge occurs at Chief Shakes hot springs (450 1pm). Bell Island Hot Springs, which has about a 100-1 pm discharge and amore » 70 C temperature, has had the most development. Two previously unreported thermal-spring sites, Barnes Lake warm springs and Bradfield hot springs, have a low rate of discharge and respective surface temperatures of about 25 and 54 C. The known thermal springs probably originate from circulation of meteoric waters through deep-seated fracture and fault systems. The chemical constituents of the alkali-sulfate to alkali-chloride thermal waters are probably derived from interaction of the deeply circulating meteoric waters with the granitic wall rocks. Chemical geothermometry suggests subsurface temperatures of 55 to 151 C. If waters are being heated solely by conduction from wall rocks, circulation depths must be about 1.5 to 5 km, assuming geothermal gradients of 30 to 50 C/km. Variations in temperature, discharge, and chemistry were noted at several thermal springs for which previous records are available. A major decrease in silica and potassium concentrations at Chief Shakes hot springs is suggested by comparing recent analyses of water chemistry to Waring's (1917) original analysis. The rate of discharge at Bell Island Hot Springs may have increased by a factor of two since Waring's visit to the springs. Subsurface reservoirs associated with thermal springs in southern Southeastern Alaska are of low temperature and are probably limited in extent, compared to geothermal fields now being used elsewhere in the world. Only the Bell Island and Bailey Bay sites now offer any potential for generation of electricity; these sites could also be used for a variety of direct uses such as space heating, wood or lumber processing, and perhaps aquaculture. The other sites have less potential but could be used locally for space heating or agriculture enhancement.« less

Phylogeography of mitochondrial DNA variation in brown bears and polar bears

USGS Publications Warehouse

Shields, Gerald F.; Adams, Deborah; Garner, Gerald W.; Labelle, Martine; Pietsch, Jacy; Ramsay, Malcolm; Schwartz, Charles; Titus, Kimberly; Williamson, Scott

2000-01-01

We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples.

Rayleigh Wave Phase Velocities in Alaska from Ambient Noise Tomography

NASA Astrophysics Data System (ADS)

Pepin, K. S.; Li, A.; Yao, Y.

2016-12-01

We have analyzed ambient noise data recorded at 136 broadband stations from the USArray Transportable Array and other permanent seismic networks in Alaska and westernmost Canada. Daily cross-correlations are obtained using vertical component seismograms and are stacked to form a single trace for each station pair. Rayleigh wave signals are extracted from the stacked traces and are used to calculate phase velocities in the Alaska region. Preliminary phase velocity maps show similar trends to those from previous studies, but also yield new anomalies given the wider geographical range provided by the Transportable Array. At short periods (6-12s), a high velocity anomaly is observed directly northeast of the Fairweather-Queen Charlotte fault, and a high velocity trend appears in the eastern Yukon terrane between the Denali and Tintina fault, probably reflecting mafic igneous crustal rocks. Significantly slow anomalies are present at the Prince William Sound, Cook Inlet, and the basins in southwestern and central Alaska, indicating sediment effects. The slow anomalies gradually shift to southeastern and south-central Alaska with increasing period (up to 40s), corresponding to the Wrangell volcano belt and the volcano arc near Cook Inlet. A broad high-velocity zone is also observed in central Alaska to the north of the Denali fault at long periods (30-40s). The Yakutat terrane is characterized as a high-velocity anomaly from period 14s to 25s but not imaged at longer periods due to poor resolution.

Postglacial vegetation history of Mitkof Island, Alexander Archipelago, southeastern Alaska

USGS Publications Warehouse

Ager, T.A.; Carrara, P.E.; Smith, Jane L.; Anne, V.; Johnson, J.

2010-01-01

An AMS radiocarbon-dated pollen record from a peat deposit on Mitkof Island, southeastern Alaska provides a vegetation history spanning ∼12,900 cal yr BP to the present. Late Wisconsin glaciers covered the entire island; deglaciation occurred > 15,400 cal yr BP. The earliest known vegetation to develop on the island (∼12,900 cal yr BP) was pine woodland (Pinus contorta) with alder (Alnus), sedges (Cyperaceae) and ferns (Polypodiaceae type). By ∼12,240 cal yr BP, Sitka spruce (Picea sitchensis) began to colonize the island while pine woodland declined. By ∼11,200 cal yr BP, mountain hemlock (Tsuga mertensiana) began to spread across the island. Sitka spruce-mountain hemlock forests dominated the lowland landscapes of the island until ∼10,180 cal yr BP, when western hemlock (Tsuga heterophylla) began to colonize, and soon became the dominant tree species. Rising percentages of pine, sedge, and sphagnum after ∼7100 cal yr BP may reflect an expansion of peat bog habitats as regional climate began to shift to cooler, wetter conditions. A decline in alders at that time suggests that coastal forests had spread into the island's uplands, replacing large areas of alder thickets. Cedars (Chamaecyparis nootkatensis, Thuja plicata) appeared on Mitkof Island during the late Holocene.

Postglacial vegetation history of Mitkof Island, Alexander Archipelago, southeastern Alaska

NASA Astrophysics Data System (ADS)

Ager, Thomas A.; Carrara, Paul E.; Smith, Jane L.; Anne, Victoria; Johnson, Joni

2010-03-01

An AMS radiocarbon-dated pollen record from a peat deposit on Mitkof Island, southeastern Alaska provides a vegetation history spanning ˜12,900 cal yr BP to the present. Late Wisconsin glaciers covered the entire island; deglaciation occurred > 15,400 cal yr BP. The earliest known vegetation to develop on the island (˜12,900 cal yr BP) was pine woodland ( Pinus contorta) with alder ( Alnus), sedges (Cyperaceae) and ferns (Polypodiaceae type). By ˜12,240 cal yr BP, Sitka spruce ( Picea sitchensis) began to colonize the island while pine woodland declined. By ˜11,200 cal yr BP, mountain hemlock ( Tsuga mertensiana) began to spread across the island. Sitka spruce-mountain hemlock forests dominated the lowland landscapes of the island until ˜10,180 cal yr BP, when western hemlock ( Tsuga heterophylla) began to colonize, and soon became the dominant tree species. Rising percentages of pine, sedge, and sphagnum after ˜7100 cal yr BP may reflect an expansion of peat bog habitats as regional climate began to shift to cooler, wetter conditions. A decline in alders at that time suggests that coastal forests had spread into the island's uplands, replacing large areas of alder thickets. Cedars ( Chamaecyparis nootkatensis, Thuja plicata) appeared on Mitkof Island during the late Holocene.

Holocene evolution of diatom and silicoflagellate paleoceanography in Slocum Arm, a fjord in southeastern Alaska

USGS Publications Warehouse

Barron, John A.; Bukry, David; Addison, Jason A.; Ager, Thomas A.

2016-01-01

Diatom and silicoflagellate assemblages in cores EW0408-47JC, -47TC, -46MC (57° 34.5278′ N, 136° 3.7764′ W, 114 m water depth) taken from the outer portion of Slocum Arm, a post-glacial fjord in southeastern Alaska, reveal the paleoclimatic and paleoceanographic evolution of the eastern margin of the Gulf of Alaska (GoA) during the past 10,000 years. Between ~ 10 and 6.8 cal ka, periods of low salinity and cool water conditions alternated with brief intervals marked by the increased influx of oceanic, more saline and likely warmer waters. Increased surface water stability characterized by a middle Holocene interval between ~ 6.8 and 3.2 cal ka is typified by increased abundances of northeastern Pacific Thalassiosira spp. that are indicative of spring coastal blooms and decreased abundances of warm and higher salinity oceanic diatoms. At ~ 3.2 cal ka, an abrupt increase in both the relative contribution of oceanic diatoms and silicoflagellates suggestive of cooler upwelling conditions occurred in the -47JC record. A stepwise increase in alkenone sea surface temperature in northern GoA core EW0408-85JC and increase in southern sourced precipitation in the carbonate δ18O record of Jellybean Lake (Yukon) present evidence that this ~ 3.2 cal ka event coincided with the onset of enhanced positive Pacific Decadal Oscillation-like (PDO) conditions in the GoA. These positive PDO-like conditions persisted until ~ 1.0 cal ka and were followed by high amplitude fluctuations in the relative abundance of diatom and silicoflagellate assemblages.

Cluster of Serogroup W135 Meningococci, Southeastern Florida, 2008–2009

PubMed Central

Mejia-Echeverry, Alvaro; Fiorella, Paul; Leguen, Fermin; Livengood, John; Kay, Robyn; Hopkins, Richard

2010-01-01

Recently, 14 persons in southeastern Florida were identified with Neisseria meningitidis serogroup W135 invasive infections. All isolates tested had matching or near-matching pulsed-field gel electrophoresis patterns and belonged to the multilocus sequence type 11 clonal complex. The epidemiologic investigation suggested recent endemic transmission of this clonal complex in southeastern Florida. PMID:20031054

Preliminary summary review of thorium-bearing mineral occurrences in Alaska

USGS Publications Warehouse

Bates, Robert G.; Wedow, Helmuth

1952-01-01

Thorium-bearing minerals are known at 47 localities in Alaska. At these localities the thorium occurs as a major constituent or in minor amounts as an impurity in one or more of the following 12 minerals: allanite, columbite, ellsworthite, eschynite, gummite, monazite, orangite, parisite, thorianite, thorite, xenotime, and zircon. In addition other minerals, such as biotite and sphene, are radioactive and may contain thorium. Several unidentified columbate minerals with uranium or thorium and uranium as major constituents have been recognized at some localities. The distribution, by type of deposit, of the 57 thorium occurrences is as follows: lode - 3, lode and placer - 1, granitic rock - 3, granitic rock and related placer - 14, and placer - 26. Of the four lode occurrences only the radioactive veins at Salmon Bay in southeastern Alaska and the contact metamorphic deposit in the Nixon Fork area of central Alaska warrant further consideration, although insufficient data are available to determine whether these two deposits have commercial possibilities. The remaining occurrences of thorium-bearing minerals in Alaska are limited to placer deposits and disseminations of accessory minerals in granitic rocks. In most of these occurrences the thorium-bearing minerals occur in only trace amounts and consequently warrent little further consideration. More data are needed to determine the possibilities of byproduct recovery of thorium-bearing minerals from several of the gold and tin placers.

Bokan Mountain peralkaline granitic complex, Alexander terrane (southeastern Alaska): evidence for Early Jurassic rifting prior to accretion with North America

USGS Publications Warehouse

Dostal, Jaroslav; Karl, Susan M.; Keppie, J. Duncan; Kontak, Daniel J.; Shellnutt, J. Gregory

2013-01-01

The circular Bokan Mountain complex (BMC) on southern Prince of Wales Island, southernmost Alaska, is a Jurassic peralkaline granitic intrusion about 3 km in diameter that crosscuts igneous and metasedimentary rocks of the Alexander terrane. The BMC hosts significant rare metal (rare earth elements, Y, U, Th, Zr, and Nb) mineralization related to the last stage of BMC emplacement. U–Pb (zircon) and 40Ar/39Ar (amphibole and whole-rock) geochronology indicates the following sequence of intrusive activity: (i) a Paleozoic basement composed mainly of 469 ± 4 Ma granitic rocks; (ii) intrusion of the BMC at 177 ± 1 Ma followed by rapid cooling through ca. 550 °C at 176 ± 1 Ma that was synchronous with mineralization associated with vertical, WNW-trending pegmatites, felsic dikes, and aegirine–fluorite veins and late-stage, sinistral shear deformation; and (iii) intrusion of crosscutting lamprophyre dikes at >150 Ma and again at ca. 105 Ma. The peralkaline nature of the BMC and the WNW trend of associated dikes suggest intrusion during NE–SW rifting that was followed by NE–SW shortening during the waning stages of BMC emplacement. The 177 Ma BMC was synchronous with other magmatic centres in the Alexander terrane, such as (1) the Dora Bay peralkaline stock and (2) the bimodal Moffatt volcanic suite located ∼30 km north and ∼100 km SE of the BMC, respectively. This regional magmatism is interpreted to represent a regional extensional event that precedes deposition of the Late Jurassic – Cretaceous Gravina sequence that oversteps the Wrangellia and Alexander exotic accreted terranes and the Taku and Yukon–Tanana pericratonic terranes of the Canadian–Alaskan Cordillera.

Bokan Mountain peralkaline granitic complex, Alexander terrane (southeastern Alaska): evidence for Early Jurassic rifting prior to accretion with North America

USGS Publications Warehouse

Dostal, Jaroslav; Karl, Susan M.; Keppie, J. Duncan; Kontak, Daniel J.; Shellnutt, J. Gregory

2013-01-01

The circular Bokan Mountain complex (BMC) on southern Prince of Wales Island, southernmost Alaska, is a Jurassic peralkaline granitic intrusion about 3 km in diameter that crosscuts igneous and metasedimentary rocks of the Alexander terrane. The BMC hosts significant rare metal (rare earth elements, Y, U, Th, Zr, and Nb) mineralization related to the last stage of BMC emplacement. U–Pb (zircon) and 40Ar/39Ar (amphibole and whole-rock) geochronology indicates the following sequence of intrusive activity: (i) a Paleozoic basement composed mainly of 469 ± 4 Ma granitic rocks; (ii) intrusion of the BMC at 177 ± 1 Ma followed by rapid cooling through ca. 550 °C at 176 ± 1 Ma that was synchronous with mineralization associated with vertical, WNW-trending pegmatites, felsic dikes, and aegirine–fluorite veins and late-stage, sinistral shear deformation; and (iii) intrusion of crosscutting lamprophyre dikes at >150 Ma and again at ca. 105 Ma. The peralkaline nature of the BMC and the WNW trend of associated dikes suggest intrusion during NE–SW rifting that was followed by NE–SW shortening during the waning stages of BMC emplacement. The 177 Ma BMC was synchronous with other magmatic centres in the Alexander terrane, such as (1) the Dora Bay peralkaline stock and (2) the bimodal Moffatt volcanic suite located ~30 km north and ~100 km SE of the BMC, respectively. This regional magmatism is interpreted to represent a regional extensional event that precedes deposition of the Late Jurassic – Cretaceous Gravina sequence that oversteps the Wrangellia and Alexander exotic accreted terranes and the Taku and Yukon–Tanana pericratonic terranes of the Canadian–Alaskan Cordillera.

PNNL Researchers Collect Permafrost Cores in Alaska

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2016-11-23

Permafrost is ground that is frozen for two or more years. In the Arctic, discontinuous regions of this saturated admixture of soil and rock store a large fraction of the Earth’s carbon – about 1672 petagrams (1672 trillion kilograms). As temperatures increase in the Northern Hemisphere, a lot of that carbon may be released to the atmosphere, making permafrost an important factor to represent accurately in global climate models. At Pacific Northwest National Laboratory, a group led by James C. Stegen periodically extracts permafrost core samples from a site near Fairbanks, Alaska. Back at the lab in southeastern Washington State,more » they study the cores for levels of microbial activity, carbon fluxes, hydrologic patterns, and other factors that reveal the dynamics of this consequential layer of soil and rock.« less

Earthquakes; January-February, 1979

USGS Publications Warehouse

Person, W.J.

1979-01-01

The first major earthquake (magnitude 7.0 to 7.9) of the year struck in southeastern Alaska in a sparsely populated area on February 28. On January 16, Iran experienced the first destructive earthquake of the year causing a number of casualties and considerable damage. Peru was hit by a destructive earthquake on February 16 that left casualties and damage. A number of earthquakes were experienced in parts of the Untied States, but only minor damage was reported. 

Inundation Mapping and Hazard Assessment of Tectonic and Landslide Tsunamis in Southeast Alaska

NASA Astrophysics Data System (ADS)

Suleimani, E.; Nicolsky, D.; Koehler, R. D., III

2014-12-01

The Alaska Earthquake Center conducts tsunami inundation mapping for coastal communities in Alaska, and is currently focused on the southeastern region and communities of Yakutat, Elfin Cove, Gustavus and Hoonah. This activity provides local emergency officials with tsunami hazard assessment, planning, and mitigation tools. At-risk communities are distributed along several segments of the Alaska coastline, each having a unique seismic history and potential tsunami hazard. Thus, a critical component of our project is accurate identification and characterization of potential tectonic and landslide tsunami sources. The primary tectonic element of Southeast Alaska is the Fairweather - Queen Charlotte fault system, which has ruptured in 5 large strike-slip earthquakes in the past 100 years. The 1958 "Lituya Bay" earthquake triggered a large landslide into Lituya Bay that generated a 540-m-high wave. The M7.7 Haida Gwaii earthquake of October 28, 2012 occurred along the same fault, but was associated with dominantly vertical motion, generating a local tsunami. Communities in Southeast Alaska are also vulnerable to hazards related to locally generated waves, due to proximity of communities to landslide-prone fjords and frequent earthquakes. The primary mechanisms for local tsunami generation are failure of steep rock slopes due to relaxation of internal stresses after deglaciation, and failure of thick unconsolidated sediments accumulated on underwater delta fronts at river mouths. We numerically model potential tsunami waves and inundation extent that may result from future hypothetical far- and near-field earthquakes and landslides. We perform simulations for each source scenario using the Alaska Tsunami Model, which is validated through a set of analytical benchmarks and tested against laboratory and field data. Results of numerical modeling combined with historical observations are compiled on inundation maps and used for site-specific tsunami hazard assessment by emergency planners.

The Climatology and Impacts of Atmospheric Rivers near the Coast of Southern Alaska

NASA Astrophysics Data System (ADS)

Nardi, K.; Barnes, E. A.; Mundhenk, B. D.

2015-12-01

Atmospheric rivers, narrow plumes of anomalously high tropospheric water vapor transport, frequently appear over the Pacific Ocean. Popularized by colloquialisms such as the "Pineapple Express," atmospheric rivers often interact with synoptic-scale disturbances to produce significant precipitation events over land masses. Previous research has focused extensively on the impacts of this phenomenon with respect to high-precipitation storms, namely during boreal winter, on the western coast of the contiguous United States. These events generate great scientific, political, and economic concerns for nearby cities, farms, and tourist destinations. Recently, researchers have investigated similar high-precipitation events along the southern coast of Alaska. Specifically, previous work has discussed several major events occurring during the September-November timeframe. One particular event, in October 2006, produced an all-time record for water levels at several river observation sites. This study examines the climatology of atmospheric rivers in the vicinity of southern Alaska. Data (1979-2014) from the Modern-Era Retrospective Analysis for Research and Applications (MERRA) is used to detect atmospheric rivers approaching, and making landfall on, the southern Alaskan coast from the Kenai Peninsula to the Gulf of Alaska region. A seasonal cycle in the strength and frequency of atmospheric rivers over Alaska is shown. Furthermore, the study assesses the synoptic conditions coincident with atmospheric rivers and examines several instances of particularly strong precipitation events. For example, wintertime atmospheric river events tend to occur when a blocking high exists over southeastern Alaska. These results have the potential to help forecasters and emergency managers predict high-precipitation events and lessen potential negative impacts.

Cobalt—Styles of deposits and the search for primary deposits

USGS Publications Warehouse

Hitzman, Murray W.; Bookstrom, Arthur A.; Slack, John F.; Zientek, Michael L.

2017-11-30

Cobalt (Co) is a potentially critical mineral. The vast majority of cobalt is a byproduct of copper and (or) nickel production. Cobalt is increasingly used in magnets and rechargeable batteries. More than 50 percent of primary cobalt production is from the Central African Copperbelt. The Central African Copperbelt is the only sedimentary rock-hosted stratiform copper district that contains significant cobalt. Its presence may indicate significant mafic-ultramafic rocks in the local basement. The balance of primary cobalt production is from magmatic nickel-copper and nickel laterite deposits. Cobalt is present in several carbonate-hosted lead-zinc and copper districts. It is also variably present in Besshi-type volcanogenic massive sulfide and siliciclastic sedimentary rock-hosted deposits in back arc and rift environments associated with mafic-ultramafic rocks. Metasedimentary cobalt-copper-gold deposits (such as Blackbird, Idaho), iron oxide-copper-gold deposits, and the five-element vein deposits (such as Cobalt, Ontario) contain different amounts of cobalt. None of these deposit types show direct links to mafic-ultramafic rocks; the deposits may result from crustal-scale hydrothermal systems capable of leaching and transporting cobalt from great depths. Hydrothermal deposits associated with ultramafic rocks, typified by the Bou Azzer district of Morocco, represent another type of primary cobalt deposit.In the United States, exploration for cobalt deposits may focus on magmatic nickel-copper deposits in the Archean and Proterozoic rocks of the Midwest and the east coast (Pennsylvania) and younger mafic rocks in southeastern and southern Alaska; also, possibly basement rocks in southeastern Missouri. Other potential exploration targets include—The Belt-Purcell basin of British Columbia (Canada), Idaho, Montana, and Washington for different styles of sedimentary rock-hosted cobalt deposits;Besshi-type VMS deposits, such as the Greens Creek (Alaska) deposit and the Ducktown (Tennessee) waste and tailings; andKnown five-element vein districts in Arizona and New Mexico, as well as in the Yukon-Tanana terrane of Alaska; and hydrothermal deposits associated with ultramafic rocks along the west coast, in Alaska, and in the Appalachian Mountains.

77 FR 4290 - TransCanada Alaska Company, LLC; Notice of Public Scoping Meeting for the Planned Alaska Pipeline...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-27

... TransCanada Alaska Company, LLC (TC Alaska) had not filed its draft Resource Reports, which we deemed necessary to properly evaluate and comment on this unique and complex project. On January 13, 2012, TC...

Seabird, fish, marine mammal, and oceanography coordinated investigations (SMMOCI) in Sitka Sound, Alaska, July 2000

USGS Publications Warehouse

Piatt, John F.; Dragoo, Donald E.

2005-01-01

Surveys for seabirds and marine mammals were conducted in and near Sitka Sound, Alaska (Fig. 1) from the M/V Tiĝlax̂ during 12-16 July 2000 (Table 1, Fig. 1). The objective was to characterize the marine environment in the vicinity of St. Lazaria Island, one of ten seabird colonies monitored annually by the Alaska Maritime National Wildlife Refuge (See Dragoo et al. 2003). In addition to censusing seabirds and mammals encountered on line transects, local oceanography was characterized by measuring water temperature and salinity continuously at the sea surface, and by taking profiles of the water column on a series of CTD transects. The relative abundance of zooplankton and fish biomass was measured using a dual -frequency echosounder. Significant acoustic targets were sampled with a m id-water trawl net. Long-lines were se t twice to catch and characterize diets of large demersal fish species.Rosenthal et al. (1981 and 1982) studied the bottomfish component of the nearshore habitats in southeastern Alaska including the Sitka Sound area during the summers of 1980 and 1981, allowing comparisons of our findings to those from the earlier works. There are no previous surveys for seabirds or marine mammals in this area with which we can compare our surveys.

Phylogeography of mitochondrial DNA variation in brown bears and polar bears.

PubMed

Shields, G F; Adams, D; Garner, G; Labelle, M; Pietsch, J; Ramsay, M; Schwartz, C; Titus, K; Williamson, S

2000-05-01

We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska's Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples. Copyright 2000 Academic Press.

Sculpted by water, elevated by earthquakes—The coastal landscape of Glacier Bay National Park, Alaska

USGS Publications Warehouse

Witter, Robert C.; LeWinter, Adam; Bender, Adrian M.; Glennie, Craig; Finnegan, David

2017-05-22

Within Glacier Bay National Park in southeastern Alaska, the Fairweather Fault represents the onshore boundary between two of Earth’s constantly moving tectonic plates: the North American Plate and the Yakutat microplate. Satellite measurements indicate that during the past few decades the Yakutat microplate has moved northwest at a rate of nearly 5 centimeters per year relative to the North American Plate. Motion between the tectonic plates results in earthquakes on the Fairweather Fault during time intervals spanning one or more centuries. For example, in 1958, a 260-kilometer section of the Fairweather Fault ruptured during a magnitude 7.8 earthquake, causing permanent horizontal (as much as 6.5 meters) and vertical (as much as 1 meter) displacement of the ground surface across the fault. Thousands to millions of years of tectonic plate motion, including earthquakes like the one in 1958, raised and shifted the ground surface across the Fairweather Fault, while rivers, glaciers, and ocean waves eroded and sculpted the surrounding landscape along the Gulf of Alaska coast in Glacier Bay National Park.

Radiometric age map of Aleutian Islands

USGS Publications Warehouse

Wilson, Frederic H.; Turner, D.L.

1975-01-01

This map includes published, thesis, and open-file radiometric data available to us as of June, 1975. Some dates are not plotted because of inadequate location data in the original references.The map is divided into five sections, based on 1:1,000,000 scale enlargements of the National Atlas maps of Alaska. Within each section (e.g., southeastern Alaska), radiometric dates are plotted and keyed to 1:250,000 scale quadrangles. Accompanying each map section is table 1, listing map numbers and the sample identification numbers used in DGGS Special Report 10: Radiometric Dates from Alaska-A 1975 Compilation”. The reader is referred to Special Report 10 for more complete information on location, rock type, dating method, and literature references for each age entry. A listing of dates in Special Report lo which require correction or deletion is included S table 2. Corrected and additional entries are listed in table 3. The listings in tables 2 and 3 follow the format of Special Report 10. Table 4 is a glossary of abbreviations used for quadrangle name, rock type, mineral dated, and type of dating method used.

Magnetite deposits near Klukwan and Haines, southeastern Alaska

USGS Publications Warehouse

Robertson, Eugene C.

1956-01-01

Low-grade iron ore is found in magnetite-bearing pyroxenite bodies near Klukwan and Haines in Southeastern Alaska. An alluvial fan at Haines also contains magnetite-bearing rock of possible economic significance. The Haines-Klukwan area is underlain by rocks of Mesozoic Including epidote diorite, quartz diorite, and alaskite of the Coast Range batholith, metabasalt (recrystallized lava flows and pyroclastic rocks), and, in the southern part, interbedded slate and limestone. Layering and foliation, where perceptible, generally strike northwest and dip steeply northeast. The iron deposits are found at or near the contact between the metabasalt and epidote diorite; they appear to represent highly-altered lava flows that were metamorphosed during the emplacement of the batholith. Several billion tens of rock containing about 13 percent magnetic iron are included in the pyroxenite body at Klukwan. Sampling and dip-needle data suggest the presence there of two or three tabular aches in which the rock has an average magnetic iron content of 20 percent or more. Pyroxenite bodies outcropping in three areas near Haines apparently are lower in grade than the Klukwan deposit; lack of exposures prevented thorough sampling but reconnaissance traverses with a dip needle failed to reveal important zones of high-grade iron ore. An alluvial fan adjoining the pyroxenite body at Klukwan contains several hundred million tons of broken rock having a magneticiron content of about 10 percent.

Use of historical logging patterns to identify disproportionately logged ecosystems within temperate rainforests of southeastern Alaska.

PubMed

Albert, David M; Schoen, John W

2013-08-01

The forests of southeastern Alaska remain largely intact and contain a substantial proportion of Earth's remaining old-growth temperate rainforest. Nonetheless, industrial-scale logging has occurred since the 1950s within a relatively narrow range of forest types that has never been quantified at a regional scale. We analyzed historical patterns of logging from 1954 through 2004 and compared the relative rates of change among forest types, landform associations, and biogeographic provinces. We found a consistent pattern of disproportionate logging at multiple scales, including large-tree stands and landscapes with contiguous productive old-growth forests. The highest rates of change were among landform associations and biogeographic provinces that originally contained the largest concentrations of productive old growth (i.e., timber volume >46.6 m³/ha). Although only 11.9% of productive old-growth forests have been logged region wide, large-tree stands have been reduced by at least 28.1%, karst forests by 37%, and landscapes with the highest volume of contiguous old growth by 66.5%. Within some island biogeographic provinces, loss of rare forest types may place local viability of species dependent on old growth at risk of extirpation. Examination of historical patterns of change among ecological forest types can facilitate planning for conservation of biodiversity and sustainable use of forest resources. © 2013 Society for Conservation Biology.

Alexander Archipelago, Southeastern Alaska

NASA Technical Reports Server (NTRS)

2002-01-01

West of British Columbia, Canada, and south of the Yukon Territory, the southeastern coastline of Alaska trails off into the islands of the Alexander Archipelago. The area is rugged and contains many long, U-shaped, glaciated valleys, many of which terminate at tidewater. The Alexander Archipelago is home to Glacier Bay National Park. The large bay that has two forks on its northern end is Glacier Bay itself. The eastern fork is Muir inlet, into which runs the Muir glacier, named for the famous Scottish-born naturalist John Muir. Glacier Bay opens up into the Icy Strait. The large, solid white area to the west is Brady Icefield, which terminates at the southern end in Brady's Glacier. To locate more interesting features from Glacier Bay National Park, take a look at the park service map. As recently as two hundred years ago, a massive ice field extended into Icy Strait and filled the Glacier Bay. Since that time, the area has experienced rapid deglaciation, with many large glaciers retreating 40, 60, even 80 km. While temperatures have increased in the region, it is still unclear whether the rapid recession is part of the natural cycle of tidewater glaciers or is an indicator of longer-term climate change. For more on Glacier Bay and climate change, read an online paper by Dr. Dorothy Hall, a MODIS Associate Science Team Member. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

Variation in responses to spawning Pacific salmon among three south-eastern Alaska streams

USGS Publications Warehouse

Chaloner, D.T.; Lamberti, G.A.; Merritt, R.W.; Mitchell, N.L.; Ostrom, P.H.; Wipfli, M.S.

2004-01-01

1. Pacific salmon are thought to stimulate the productivity of the fresh waters in which they spawn by fertilising them with marine-derived nutrients (MDN). We compared the influence of salmon spawners on surface streamwater chemistry and benthic biota among three southeastern Alaska streams. Within each stream, reaches up- and downstream of barriers to salmon migration were sampled during or soon after spawners entered the streams. 2. Within streams, concentrations of dissolved ammonium and soluble reactive phosphorus (SRP), abundance of epilithon (chlorophyll a and ash-free dry mass) and biomass of chironomids were significantly higher in reaches with salmon spawners. In contrast, biomass of the mayflies Epeorus spp. and Rhithrogena spp. was significantly higher in reaches lacking spawners. 3. Among streams, significant differences were found in concentrations of dissolved ammonium, dissolved organic carbon, nitrate and SRP, abundance of epilithon, and the biomass of chironomids and Rhithrogena. These differences did not appear to reflect differences among streams in spawner density, nor the changes in water chemistry resulting from salmon spawners. 4. Our results suggest that the 'enrichment' effect of salmon spawners (e.g. increased streamwater nutrient concentrations) was balanced by other concurrent effects of spawners on streams (e.g. sediment disturbance). Furthermore, the collective effect of spawners on lotic ecosystems is likely to be constrained by conditions unique to individual streams, such as temperature, background water chemistry and light attenuation.

ERTS-1 data as a teaching and research tool in the Department of Geology

NASA Technical Reports Server (NTRS)

Grybeck, D. (Principal Investigator)

1973-01-01

The author has identified the following significant results. During the sixth bi-monthly period, a mosaic was constructed in MSS band 6 of the southeastern one-half of Alaska. A mosaic of the whole state awaits additional coverage to fill in some gaps. In addition, new material is being monitored as it arrived at the Geophysical Institute and from the NASA Indices for inclusion into the departmental collections. No geology courses are being taught during the summer.

Evaluating fuel complexes for fire hazard mitigation planning in the southeastern United States

Treesearch

Anne G. Andreu; Dan Shea; Bernard R. Parresol; Roger D. Ottmar

2012-01-01

Fire hazard mitigation planning requires an accurate accounting of fuel complexes to predict potential fire behavior and effects of treatment alternatives. In the southeastern United States, rapid vegetation growth coupled with complex land use history and forest management options requires a dynamic approach to fuel characterization. In this study we assessed...

Spatial distribution of mercury in southeastern Alaskan streams influenced by glaciers, wetlands, and salmon

USGS Publications Warehouse

Nagorski, Sonia A.; Engstrom, Daniel R.; Hudson, John P.; Krabbenhoft, David P.; Hood, Eran; DeWild, John F.; Aiken, George R.

2014-01-01

Southeastern Alaska is a remote coastal-maritime ecosystem that is experiencing increased deposition of mercury (Hg) as well as rapid glacier loss. Here we present the results of the first reported survey of total and methyl Hg (MeHg) concentrations in regional streams and biota. Overall, streams draining large wetland areas had higher Hg concentrations in water, mayflies, and juvenile salmon than those from glacially-influenced or recently deglaciated watersheds. Filtered MeHg was positively correlated with wetland abundance. Aqueous Hg occurred predominantly in the particulate fraction of glacier streams but in the filtered fraction of wetland-rich streams. Colonization by anadromous salmon in both glacier and wetland-rich streams may be contributing additional marine-derived Hg. The spatial distribution of Hg in the range of streams presented here shows that watersheds are variably, yet fairly predictably, sensitive to atmospheric and marine inputs of Hg.

Distribution of ground-nesting marine birds along shorelines in Glacier Bay, southeastern Alaska: An assessment related to potential disturbance by back-country users

USGS Publications Warehouse

Arimitsu, Mayumi L.; Piatt, John F.; Romano, Marc D.

2007-01-01

With the exception of a few large colonies, the distribution of ground-nesting marine birds in Glacier Bay National Park in southeastern Alaska is largely unknown. As visitor use increases in back-country areas of the park, there is growing concern over the potential impact of human activities on breeding birds. During the 2003–05 breeding seasons, the shoreline of Glacier Bay was surveyed to locate ground-nesting marine birds and their nesting areas, including wildlife closures and historical sites for egg collection by Alaska Native peoples. The nesting distribution of four common ground-nesting marine bird species was determined: Arctic Tern (Sterna paradisaea), Black Oystercatcher (Haematopus bachmani), Mew Gull (Larus canus), and Glaucous-winged Gull (Larus glaucescens). Observations of less abundant species also were recorded, including Herring Gull (Larus argentatus), Red-throated Loon (Gavia stellata), Canada Goose (Branta canadensis), Willow Ptarmigan (Lagopus lagopus), Semipalmated Plover (Charadrius semipalmatus), Spotted Sandpiper (Actitis macularia), Least Sandpiper (Calidris minutilla), Parasitic Jaeger (Stercorarius parasiticus), and Aleutian Tern (Sterna aleutica). Nesting distribution for Arctic Terns was largely restricted to the upper arms of the bay and a few treeless islets in the lower bay, whereas Black Oystercatchers were more widely distributed along shorelines in the park. Mew Gulls nested throughout the upper bay in Geikie Inlet and in Fingers and Berg Bays, and most Glaucous-winged Gull nests were found at wildlife closures in the central and lower bays. Several areas were identified where human disturbance could affect breeding birds. This study comprises the first bay-wide survey for the breeding distribution of ground-nesting marine birds in Glacier Bay National Park, providing a minimum estimate of their numbers and distribution within the park. This information can be used to assess future human disturbance and track natural changes in nesting bird distribution over time.

1500 Years of Annual Climate and Environmental Variability as Recorded in Bona-Churchill (Alaska) Ice Cores

NASA Astrophysics Data System (ADS)

Thompson, L. G.; Mosley-Thompson, E. S.; Zagorodnov, V.; Davis, M. E.; Mashiotta, T. A.; Lin, P.

2004-12-01

In 2003, six ice cores measuring 10.5, 11.5, 11.8, 12.4, 114 and 460 meters were recovered from the col between Mount Bona and Mount Churchill (61° 24'N; 141° 42'W; 4420 m asl). These cores have been analyzed for stable isotopic ratios, insoluble dust content and concentrations of major chemical species. Total Beta radioactivity was measured in the upper sections. The 460-meter core, extending to bedrock, captured the entire depositional record at this site where ice temperatures ranged from -24° C at 10 meters to -19.8° C at the ice/bedrock contact. The shallow cores allow assessment of surface processes under modern meteorological conditions while the deep core offers a ˜1500-year climate and environmental perspective. The average annual net balance is ˜~1000 mm of water equivalent and distinct annual signals in dust and calcium concentrations along with δ 18O allow annual resolution over most of the core. The excess sulfate record reflects many known large volcanic eruptions such as Katmai, Krakatau, Tambora, and Laki which allow validation of the time scale in the upper part of the core. The lower part of the core yields a history of earlier volcanic events. The 460-m Bona-Churchill ice core provides a detailed history of the `Little Ice Age' and medieval warm periods for southeastern Alaska. The source of the White River Ash will be discussed in light of the evidence from this core. The 460-m core also provides a long-term history of the dust fall that originates in north-central China. The annual ice core-derived climate records from southeastern Alaska will facilitate an investigation of the likelihood that the high resolution 1500-year record from the tropical Quelccaya Ice Cap (Peru) preserves a history of the variability of both the PDO and the Aleutian Low.

Linking Quaternary Climate Changes to Mountain Building in Southeastern Alaska

NASA Astrophysics Data System (ADS)

Dunn, C. A.; Enkelmann, E.; Allen, W. K.; Ridgway, K.

2015-12-01

The Chugach-St. Elias Mountains in southeastern Alaska exhibit extreme topography as a result of the subduction and collision of the Yakutat microplate with the North American plate. Extensive glaciation in the area, coupled with the active tectonics, makes the Chugach-St. Elias Mountains the ideal site to investigate the resulting spatial and temporal variations in exhumation. The St. Elias Mountains have experienced three major climate changes including the start of regional glaciation at ~5.5 Ma, the onset of glaciation in the Northern Hemisphere during the Plio-Pleistocene Transition to colder temperatures at 2.5 Ma, and a change in global climate cyclicity during the mid-Pleistocene Transition from 1.2-0.7 Ma. Our goal is to determine whether these climate changes result in shifts in the rates and patterns of regional exhumation due to the intensification of glacial erosion. We investigate the late Cenozoic sediments from five boreholes that were drilled by IODP Expedition 341 along a transect crossing the Yakutat shelf (offshore Bering glacier) and into the deep-sea Surveyor Fan in the Gulf of Alaska. Magnetostratigraphy and biostratigraphy on these sediments establish an up to 10 Ma depositional history in the boreholes. To study rock exhumation of the sediment source over time, 17 detrital samples from various depths in the cores were dated using zircon fission track thermochronology. Single grain cooling ages range from 302.8 Ma to 0.2 Ma, and contain composite age populations with peaks coinciding with major regional tectonic events providing information on sediment provenance and exhumation. All single grains were also double dated using U-Pb dating to identify and eliminate volcanic grains from the sample. Common U-Pb age populations are 53, 62, 70, and 98 Ma with minor populations of 117, 154, and 170 Ma. These ages are being used to better constrain sediment provenance and reconstruct past glacial catchments.

Zoned Cr, Fe-spinel from the La Perouse layered gabbro, Fairweather Range, Alaska

USGS Publications Warehouse

Czamanske, G.K.; Himmelberg, G.R.; Goff, F.E.

1976-01-01

Zoned spinel of unusual composition and morphology has been found in massive pyrrhotite-chalcopyrite-pent-landite ore from the La Perouse layered gabbro intrusion in the Fairweather Range, southeastern Alaska. The spinel grains show continuous zoning from cores with up to 53 wt.% Cr2O3 to rims with less than 11 wt.% Cr2O3. Their composition is exceptional because they contain less than 0.32 wt.% MgO and less than 0.10 wt.% Al2O3 and TiO2. Also notable are the concentrations of MnO and V2O3, which reach 4.73 and 4.50 wt.%, respectively, in the cores. The spinel is thought to have crystallized at low oxygen fugacity and at temperatures above 900??C, directly from a sulfide melt that separated by immiscibility from the gabbroic parental magma. ?? 1976.

Hydrologic effects of the earthquake of March 27, 1964, outside Alaska, with sections on Hydroseismograms from the Nunn-Bush Shoe Co. well, Wisconsin, and Alaska earthquake effects on ground water in Iowa: Chapter C in The Alaska earthquakes, March 27, 1964: effects on hydrologic regimen

USGS Publications Warehouse

Vorhis, Robert C.; Rexin, Elmer E.; Coble, R.W.

1967-01-01

The Alaska earthquake of March 27, 1964, had widespread hydrologic effects throughout practically all of the United States. More than 1,450 water-level recorders, scattered throughout all the 50 States except Connecticut, Delaware, and Rhode Island, registered the earthquake. Half of the water-level records were obtained from ground-water observation wells and half at surface-water gaging stations. The earthquake is also known to have registered on water-level recorders on wells in Canada, England, Denmark, Belgium, Egypt, Israel, Libya, Philippine Islands, South-West Africa, South Africa, and Northern Territory of Australia. The Alaska earthquake is the first for which widespread surface-water effects are known. The effects were recorded at stations on flowing streams, rivers, reservoirs, lakes, and ponds. The 755 surface-water stations recording effects are spread through 38 States, but are most numerous in the south-central and southeastern States, especially in Florida and Louisiana. Most of the fluctuations recorded can be referred to more precisely as seismic seiches; however, a few stations recorded the quake as a minor change in stage. The largest recorded seiche outside Alaska was 1.83 feet on a reservoir in Michigan. The next largest was 1.45 feet on Lake Ouachita in Arkansas. The largest fluctuation in a well was 23 feet registered by a pressure recorder near Belle Fourche, S. Dak. Fluctuations of more than 10 feet were reported from wells in Alabama, Florida, Georgia, Illinois, Missouri, and Pennsylvania. A 3.40-foot fluctuation was recorded in a well in Puerto Rico. The Alaska earthquake was registered by about seven times as many water-level recorders as recorded the Hebgen Lake, Mont., earthquake of August 19, 1959.

A Coast Mountains provenance for the Valdez and Orca groups, southern Alaska, based on Nd, Sr, and Pb isotopic evidence

USGS Publications Warehouse

Farmer, G.L.; Ayuso, R.; Plafker, G.

1993-01-01

Nd, Sr, and Pb isotopic data were obtained for fourteen fine- to coarse-grained samples of accreted flysch of the Late Cretaceous and early Tertiary Valdez and Orca Groups in southern Alaska to determine the flysch provenance. Argillites and greywackes from the Orca Group, as well as compositionally similar but higher metamorphic grade rocks from the Valdez Group, show a restricted range of correlated ??{lunate}Nd ( -0.6 to -3.8) and 87Sr 86Sr (0.7060-0.7080) at the time of sediment deposition ( ??? 50 Ma). Pb isotopic compositions also vary over a narrow range ( 206Pb 204Pb = 19.138-19.395, 207Pb 204Pb = 15.593-15.703, 208Pb 204Pb = 38.677-39.209), and in the Orca Group the samples generally become more radiogenic with decreasing ??{lunate}Nd and increasing 87Sr 86Sr. All samples have similar trace element compositions characterized by moderate light rare earth element enrichments, and low ratios of high field strength elements to large ion lithophile elements. Based on petrographic, geochemical, and isotopic data the sedimentary rocks are interpreted to have been derived largely from a Phanerozoic continental margin arc complex characterized by igneous rocks with ??{lunate}Nd values between 0 and -5. The latter conclusion is supported by the ??{lunate}Nd values of a tonalite clast and a rhyodacite clast in the Orca Group (??{lunate}Nd = -4.9 and -0.9, respectively). However, trondjemitic clasts in the Orca Group have significantly lower ??{lunate}Nd ( ??? -10) and require a derivation of a portion of the flysch from Precambrian crustal sources. The Nd, Sr, and Pb isotopic compositions of both the Valdez and Orca Groups overlap the values determined for intrusive igneous rocks exposed within the northern portion of the Late Cretaceous to early Tertiary Coast Mountains Plutonic Complex in western British Columbia and equivalent rocks in southeastern Alaska. The isotopic data support previous conclusions based on geologic studies which suggest that the flysch was shed from this portion of the batholith, and from overlying continental margin arc-related volcanic rocks, following its rapid uplift in the Late Cretaceous and early Tertiary. The Precambrian crustal material present in the flysch may have been derived from Late Proterozoic or older metasedimentary and metaigneous rocks now exposed along the western margin of the Coast Mountains Plutonic Complex. ?? 1993.

Recruiting first generation college students into the Geosciences: Alaska's EDGE project

NASA Astrophysics Data System (ADS)

Prakash, A.; Connor, C.

2008-12-01

Funded in 2005-2008, by the National Science Foundation's Geoscience Education Division, the Experiential Discoveries in Geoscience Education (EDGE) project was designed to use glacier and watershed field experiences as venues for geospatial data collected by Alaska's grade 6-12 middle and high school teachers and their students. EDGE participants were trained in GIS and learned to analyze geospatial data to answer questions about the warming Alaska environment and to determine rates of ongoing glacier recession. Important emphasis of the program was the recruitment of Alaska Native students of Inupiat, Yup'ik, Athabascan, and Tlingit populations, living in both rural and urban areas around the state. Twelve of Alaska's 55 school districts have participated in the EDGE program. To engage EDGE students in the practice of scientific inquiry, each was required to carry out a semester scale research project using georeferenced data, guided by their EDGE teacher and mentor. Across Alaska students investigated several Earth systems processes including freezing conditions of lake ice; the changes in water quality in storm drains after rainfall events; movements of moose, bears, and bison across Alaskan landscapes; changes in permafrost depth in western Alaska; and the response of migrating waterfowl to these permafrost changes. Students correlated the substrate beneath their schools with known earthquake intensities; measured cutbank and coastal erosion on northern rivers and southeastern shorelines; tracked salmon infiltration of flooded logging roads; noted the changing behavior of eagles during late winter salmon runs; located good areas for the use of tidal power for energy production; tracked the extent and range of invasive plant species with warming; and the change of forests following deglaciation. Each cohort of EDGE students and teachers finished the program by attended a 3-day EDGE symposium at which students presented their research projects first in a practice sessions at the University and then in an actual competition in a Regional High School Science Fair at which they could qualify to compete at the Intel International Science and Engineering fair. Thirty-four teachers, 30 high school students (over 40 percent of whom were Alaska Native) and over 1000 middle school students (25 percent Alaska natives) participated in EDGE activities, increasing their knowledge of Earth science, GIS skills, and data management and analysis. More information on the EDGE project is available at www.edge.alaska.edu.

Alaska: Glaciers of Kenai Fjords National Park and Katmai National Park and Preserve (Chapter 12)

NASA Technical Reports Server (NTRS)

Giffen, Bruce A.; Hall, Dorothy K.; Chien, Janet Y.L.

2007-01-01

Much recent research points to the shrinkage of the Earth's small glaciers, however, few studies have been performed to quantify the amount of change over time. We measured glacier-extent changes in two national parks in southeastern Alaska. There are hundreds of glaciers in Kenai Fjords National Park (KEFJ) and Katmai National Park and Preserve (KATM) covering over 2373 sq km of parkland. There are two primary areas of glaciation in KEFJ - the Harding Icefield and the Grewingk-Yalik Glacier Complex, and three primary areas of glaciation in KATM - the Mt. Douglas area, the Kukak Volcano to Mt. Katmai area and the Mt. Martin area. We performed glacier mapping using satellite imagery, from the 1970s, 1980s, and from 2000. Results of the analysis show that there has been a reduction in the amount of glacier ice cover in the two parks over the study period, of approximately 22 sq km of ice, approximately - 1.6% from 1986 to 2000 (for KEFJ), and of approximately 76 sq km of glacier ice, or about -7.7% from 1986187 to 2000 (for KATM). In the future, measurements of surface elevation changes of these ice masses should be acquired; together with our extent-change measurements, the volume change of the ice masses can then be determined to estimate their contribution to sea-level rise. The work is a continuation of work done in KEFJ, but in KATM, our measurements represent the first comprehensive study of the glaciers in this remote, little-studied area.

Geophysical interpretation of U, Th, and rare earth element mineralization of the Bokan Mountain peralkaline granite complex, Prince of Wales Island, southeast Alaska

USGS Publications Warehouse

McCafferty, Anne E.; Stoeser, Douglas B.; Van Gosen, Bradley S.

2014-01-01

A prospectivity map for rare earth element (REE) mineralization at the Bokan Mountain peralkaline granite complex, Prince of Wales Island, southeastern Alaska, was calculated from high-resolution airborne gamma-ray data. The map displays areas with similar radioelement concentrations as those over the Dotson REE-vein-dike system, which is characterized by moderately high %K, eU, and eTh (%K, percent potassium; eU, equivalent parts per million uranium; and eTh, equivalent parts per million thorium). Gamma-ray concentrations of rocks that share a similar range as those over the Dotson zone are inferred to locate high concentrations of REE-bearing minerals. An approximately 1300-m-long prospective tract corresponds to shallowly exposed locations of the Dotson zone. Prospective areas of REE mineralization also occur in continuous swaths along the outer edge of the pluton, over known but undeveloped REE occurrences, and within discrete regions in the older Paleozoic country rocks. Detailed mineralogical examinations of samples from the Dotson zone provide a means to understand the possible causes of the airborne Th and U anomalies and their relation to REE minerals. Thorium is sited primarily in thorite. Uranium also occurs in thorite and in a complex suite of ±Ti±Nb±Y oxide minerals, which include fergusonite, polycrase, and aeschynite. These oxides, along with Y-silicates, are the chief heavy REE (HREE)-bearing minerals. Hence, the eU anomalies, in particular, may indicate other occurrences of similar HREE-enrichment. Uranium and Th chemistry along the Dotson zone showed elevated U and total REEs east of the Camp Creek fault, which suggested the potential for increased HREEs based on their association with U-oxide minerals. A uranium prospectivity map, based on signatures present over the Ross-Adams mine area, was characterized by extremely high radioelement values. Known uranium deposits were identified in the U-prospectivity map, but the largest tract occurs over a radioelement-rich granite phase within the pluton that is likely not related to mineralization. Neither mineralization type displays a well-defined airborne magnetic signature.

Habitat Suitability Index Models: Red king crab

USGS Publications Warehouse

Jewett, Stephen C.; Onuf, Christopher P.

1988-01-01

A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for evaluating habitat of different life stages of red king crab (Paralithodes camtschatica). A model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) and 1.0 (optimum habitat) in Alaskan coastal waters, especially in the Gulf of Alaska and the southeastern Bering Sea. HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

33 CFR 165.1710 - Port Valdez and Valdez Narrows, Valdez, Alaska-security zones.

Code of Federal Regulations, 2010 CFR

2010-07-01

... following areas are security zones: (1) Trans-Alaska Pipeline (TAPS) Valdez Terminal complex (Terminal), Valdez, Alaska and TAPS tank vessels. All waters enclosed within a line beginning on the southern... TAPS tank vessel maneuvering to approach, moor, unmoor or depart the TAPS Terminal or transiting...

The Early Jurassic Bokan Mountain peralkaline granitic complex (southeastern Alaska): geochemistry, petrogenesis and rare-metal mineralization

USGS Publications Warehouse

Dostal, Jaroslav; Kontak, Daniel J.; Karl, Susan M.

2014-01-01

The Early Jurassic (ca. 177 Ma) Bokan Mountain granitic complex, located on southern Prince of Wales Island, southernmost Alaska, cross-cuts Paleozoic igneous and metasedimentary rocks of the Alexander terrane of the North American Cordillera and was emplaced during a rifting event. The complex is a circular body (~3 km in diameter) of peralkaline granitic composition that has a core of arfvedsonite granite surrounded by aegirine granite. All the rock-forming minerals typically record a two-stage growth history and aegirine and arfvedsonite were the last major phases to crystalize from the magma. The Bokan granites and related dikes have SiO2 from 72 to 78 wt. %, high iron (FeO (tot) ~3-4.5 wt. %) and alkali (8-10 wt.%) concentrations with high FeO(tot)/(FeO(tot)+MgO) ratios (typically >0.95) and the molar Al2O3/(Na2O+K2O) ratio Nd values which are indicative of a mantle signature. The parent magma is inferred to be derived from an earlier metasomatized lithospheric mantle by low degrees of partial melting and generated the Bokan granitic melt through extensive fractional crystallization. The Bokan complex hosts significant rare-metal (REE, Y, U, Th, Nb) mineralization that is related to the late-stage crystallization history of the complex which involved the overlap of emplacement of felsic dikes, including pegmatite bodies, and generation of orthomagmatic fluids. The abundances of REE, HFSE, U and Th as well as Pb and Nd isotopic values of the pluton and dikes were modified by orthomagmatic hydrothermal fluids highly enriched in the strongly incompatible trace elements, which also escaped along zones of structural weakness to generate rare-metal mineralization. The latter was deposited in two stages: the first relates to the latest stage of magma emplacement and is associated with felsic dikes that intruded along the faults and shear deformations, whereas the second stage involved ingress of hydrothermal fluids that both remobilized and enriched the initial magmatic mineralization. Mineralization is mostly composed of new minerals. Fluorine complexing played a role during the transportation of REE and HFSE in hydrothermal fluids and oxygen isotopes in the granites and quartz veins negate the significant incursion of an external fluid and support a dominantly orthomagmatic hydrothermal system. Many other REE-HFSE deposits hosted by peralkaline felsic rocks (nepheline syenites, peralkaline granites and peralkaline trachytes) were formed by a similar two stage process.

Possible refugia in the Alexander Archipelago of southeastern Alaska during the late Wisconsin glaciation

USGS Publications Warehouse

Carrara, P.E.; Ager, T.A.; Baichtal, J.F.

2007-01-01

The interpretation of the extent of late Wisconsin glaciation in southeastern Alaska has varied between geologists and biologists. Maps and reports of the region prepared by geologists commonly indicated that late Wisconsin ice extended as a large uniform front west to the edge of the continental shelf. However, the distribution of plants and animals in the region has led many biologists to suggest that there may have been ice-free areas that served as refugia during the late Wisconsin. Based on analyses of aerial photographs, topographic maps, and bathymetric charts, in conjunction with a review of previous literature and reconnaissance fieldwork throughout the region, this study presents data supporting a limited ice extent in the Alexander Archipelago during the late Wisconsin and identifies possible ice-free areas that may have served as refugia. These areas include (1) the Fairweather Ground, (2) the Herbert Graves Island area, (3) the western coast of southern Baranof Island and adjacent continental shelf, (4) Coronation Island and the adjacent continental shelf, (5) the Warren Island area, (6) the continental shelf from west of Heceta Island to Forrester Island in the south, (7) parts of the west coast of southern Dall Island, and (8) lowland areas in southern Prince of Wales Island. The identification of these possible refugia has bearing on the recolonization of the Alexander Archipelago, as they could have served as centers of biotic dispersal upon regional deglaciation and as stepping stones for early humans with a maritime tradition entering the western hemisphere from Asia. ?? 2007 NRC Canada.

The Mount Edgecumbe tephra deposits, a marker horizon in southeastern Alaska near the Pleistocene-Holocene boundary

USGS Publications Warehouse

Riehle, J.R.; Mann, D.H.; Peteet, D.M.; Engstrom, D.R.; Brew, D.A.; Meyer, C.E.

1992-01-01

Late Pleistocene tephra deposits found from Sitka to Juneau and Lituya Bay are assigned to a source at the Mount Edgecumbe volcanic field, based on similarity of glass compositions to nearvent deposits and on thinning away from Kruzof Island. The sequence of near-vent layers is basaltic andesite and andesite at the base, rhyolite, and mixed dacite and rhyolite on top. The only breaks in the tephra sequence are two 1-mm-thick silt partings in a lake-sediment core, indicating a depositional interval from basaltic andesite to dacite of no more than about a millennium. Tephra deposits at sites >30 km from the vent are solely dacite and rhyolite and are 10,600 to 11,400 14C yr old based on interpretation of 18 radiocarbon ages, including 5 by accelerator mass spectrometry (AMS). Basaltic andesite and andesite deposits nearer the vent are as much as 12,000 yr old. Discrepancy among radiocarbon ages of upland tephra deposits provisionally correlated as the same grainfall is resolvable within ??2 ?? of analytical uncertainty. Comparison of bulk and AMS ages in one sediment core indicates a systematic bias of +600 to +1100 yr for the bulk ages; correlation of tephra deposits among upland and lacustrine sites implies an additional discrepancy of 200-400 yr between upland (relatively too young) and lacustrine ages. In any case, the Mount Edgecumbe tephra deposits are a widespread, latest Pleistocene stratigraphic marker that serves to emphasize the uncertainty in dating biogenic material from southeastern Alaska. ?? 1992.

Element concentrations in soils and other surficial materials of Alaska

USGS Publications Warehouse

Gough, L.P.; Severson, R.C.; Shacklette, H.T.

1988-01-01

Mean concentrations of 35 elements, ash yields, and pH have been estimated for samples of sils and other unconsolidated surficial materials from 266 collection locations throughout Alaska. These background values can be applied to studies of environmental geochemistry and health, wildlife management, and soil-forming processes in cold climates and to computation of element abundances on a regional or worldwide scale. Limited data for an additoinal eight elements are also presented. Materials were collected using a one-way, three-level, analysis-of-variance samplling design in which collecting procedures were simplified for the convenience of the many volunteer field workers. The sample collectors were asked to avoid locations of known mineral deposits and obvious contamination, to take samples at a depth of about 20 cm where possible, and to take a replicate sample about 100 m distant from the first sample collected. With more than 60 percent of the samples replicated and 14 percent of the samples split for duplicate laboratory analyses, reliable estimates were made of the variability in element concentrations at two geographic scales and of the error associated with sample handling and laboratory procedures. Mean concentrations of most elements in surficial materials from the state of alaska correspond well with those reported in similar materials from the conterminous United STatess. Most element concentrations and ranges in samples of stream and lake sediments from Alaska, however, as reported in the literature, do not correspond well with those found in surficial materials of this study. This lack of correspondence is attributed to (1) a merger of two kinds ofsediments (stream and lake) for calculating means; (2) elimination from the sediment mean calculations of values below the limit of quantitative determination; (3) analytical methods different from those of the surficial materials study; and (4) most importantly, the inherent differences in chemistry of the materials. The distribution of variability in element concentrations o Alaskan surficial-material samples was, for most elements, largely among sampling locations, with only a samll part of the variability occurring between replicate samples at a location. The geochemical uniformity within sampling locations in Alaska is an expression of uniform geochemical cycling processes within small geographic areas. The concentration values for 35 elements in 266 samples were plotted on maps by symbols representing classes of concentration frequency distributions. These plotted symbols form patterns that may or may not be possible to interpret but nevertheless show differences that are observable at several geographical scales. The largest pattern is one generally low concentrations of many elements in materials from arctic and oceanic tundra regions, as contrasted to their often high concentrations in samples from interior and southeastern Alaska. The patttern for sodium isespecially pronounced. Intermediate-sized patterns are shown, for example, by the generally high values for magnesium and low values for silicon in the coastal forest region of southeastern Alaska. Many elements occur at low concentratoins in samples from the Alaskan peninsula and the Aleutian Islands. The degree of confidence in patterns of element abundance is expected to be in direct proportion to the number of samples included in the area. As the patterns become smaller, the probability increases that the patterns are not reproducible.

Early life ecology of Alaska plaice ( Pleuronectes quadrituberculatus) in the eastern Bering Sea: Seasonality, distribution, and dispersal

NASA Astrophysics Data System (ADS)

Duffy-Anderson, Janet T.; Doyle, Miriam J.; Mier, Kathryn L.; Stabeno, Phyllis J.; Wilderbuer, Thomas K.

2010-07-01

We examined the patterns of abundance and distribution of Alaska plaice, Pleuronectes quadrituberculatus, eggs, larvae and pelagic juveniles over the southeastern Bering Sea shelf to better understand factors controlling transport and recruitment of flatfish in the Bering Sea. Ichthyoplankton data were derived from plankton surveys conducted in 1997, 1999, 2002, 2003, and 2005. Temperature, salinity, depth, and abundance of microzooplankton were measured concurrently. Eggs and larvae were primarily collected from depths < 200 m, with the majority occurring over bottom depths ranging 50-100 m. Eggs were present throughout the water column, though densities of preflexion stage larvae were concentrated at depths 10-20 m. There was no evidence of vertical migration for pre-flexion stages. Spawning in Alaska plaice occurs primarily east of Port Moller in April and May, and eggs and larvae appear to drift to the north and northeast, an observation based on satellite-tracked drifter information, model output, and collections of older, later-stage postlarvae. Connectivity between spawning areas and nursery habitats is likely influenced by wind forcing, so climate-mediated changes to dispersal trajectory or timing is expected to have significant impacts on recruitment in this species, though entrainment in consistent, directional currents may modify these effects.

Time-slice maps showing age, distribution, and style of deformation in Alaska north of 60° N.

USGS Publications Warehouse

Moore, Thomas E.; Box, Stephen E.

2016-08-29

The structural architecture of Alaska is the product of a complex history of tectonism that occurred along the Cordilleran and Arctic margins of North America through interactions with ancient and modern ocean plates and with continental elements derived from Laurentia, Siberia, and Baltica. To unravel the tectonic history of Alaska, we constructed maps showing the age, distribution, structural style, and kinematics of contractional and penetrative extensional deformation in Alaska north of latitude 60° N. at a scale of 1:5,000,000. These maps use the Geologic Map of the Arctic (Harrison and others, 2011) as a base map and follow the guidelines in the Tectonic Map of the Arctic project (Petrov and others, 2013) for construction, including use of the International Commission on Stratigraphy time scale (Cohen and others, 2013) divided into 20 time intervals. We find evidence for deformation in 14 of the 20 time intervals and present maps showing the known or probable extent of deformation for each time interval. Maps and descriptions of deformational style, age constraints, kinematics, and information sources for each deformational episode are discussed in the text and are reported in tabular form. This report also contains maps showing the lithologies and structural geology of Alaska, a terrane map, and the distribution of tectonically important units including post-tectonic sedimentary basins, accretionary complexes, ophiolites, metamorphic rocks.These new maps show that most deformational belts in Alaska are relatively young features, having developed during the late Mesozoic and Cenozoic. The oldest episode of deformation recognized anywhere in Alaska is found in the basement of the Farewell terrane (~1.75 Ga). Paleozoic and early Mesozoic deformational events, including Devonian deformation in the Arctic Alaska terrane, Pennsylvanian deformation in the Alexander terrane, Permian deformation in the Yukon Composite (Klondike orogeny) and Farewell terranes (Browns Fork orogeny), Early and Late Jurassic deformation in the Peninsular-Wrangellia terranes, and Early Cretaceous deformation in northern Alaska (early Brookian orogeny) show that within-terrane amalgamation events occurred prior to assembly of Alaska. Widespread episodes of deformation in the Late Cretaceous and early Cenozoic, in contrast, affected multiple terranes, indicating they occurred during or following the time of assembly of most of Alaska.The primary deformational event in northern Alaska was the Late Jurassic and Early Cretaceous (early) Brookian orogeny, which affected most terranes north and west of the early Cenozoic Tintina, Victoria Creek, Kaltag, and Poorman dextral-slip faults in central Alaska. In southern Alaska, formation of the southern Alaska accretionary complex (Chugach, Prince William, Yakutat terranes) and associated magmatism in the Peninsular-Wrangellia terrane began near the Triassic-Jurassic boundary and continued episodically throughout the remainder of the Mesozoic and the Cenozoic. The collision of these terranes with the Farewell and Yukon Composite terranes in central Alaska is recorded by contractional deformation that emanated from the intervening basins in the Late Cretaceous. The boundary between northern and central Alaska is constrained to late Early Cretaceous but is enigmatic and not obviously marked by contractional deformation. Early Cenozoic shortening and transpressional deformation is the most widespread event recorded in Alaska and produced the widespread late Brookian orogenic event in northern Alaska. Middle and late Cenozoic shortening and transpression is significant in southern Alaska inboard of the underthrusting Yakutat terrane at the Pacific margin subduction zone as well as in northeastern Alaska.

New Evidence for Quaternary Strain Partitioning Along the Queen Charlotte Fault System, Southeastern Alaska

NASA Astrophysics Data System (ADS)

Walton, M. A. L.; Miller, N. C.; Brothers, D. S.; Kluesner, J.; Haeussler, P. J.; Conrad, J. E.; Andrews, B. D.; Ten Brink, U. S.

2017-12-01

The Queen Charlotte Fault (QCF) is a fast-moving ( 53 mm/yr) transform plate boundary fault separating the Pacific Plate from the North American Plate along western Canada and southeastern Alaska. New high-resolution bathymetric data along the fault show that the QCF main trace accommodates nearly all strike-slip plate motion along a single narrow deformation zone, though questions remain about how and where smaller amounts of oblique convergence are accommodated along-strike. Obliquity and convergence rates are highest in the south, where the 2012 Haida Gwaii, British Columbia MW 7.8 thrust earthquake was likely caused by Pacific underthrusting. In the north, where obliquity is lower, aftershocks from the 2013 Craig, Alaska MW 7.5 strike-slip earthquake also indicate active convergent deformation on the Pacific (west) side of the plate boundary. Off-fault structures previously mapped in legacy crustal-scale seismic profiles may therefore be accommodating part of the lesser amounts of Quaternary convergence north of Haida Gwaii. Between 2015 and 2017, the USGS acquired more than 8,000 line-km of offshore high-resolution multichannel seismic (MCS) data along the QCF to better understand plate boundary deformation. The new MCS data show evidence for Quaternary deformation associated with a series of elongate ridges located within 30 km of the QCF main trace on the Pacific side. These ridges are anticlinal structures flanked by growth faults, with recent deformation and active fluid flow characterized by seafloor scarps and seabed gas seeps at ridge crests. Structural and morphological evidence for contractional deformation decreases northward along the fault, consistent with a decrease in Pacific-North America obliquity along the plate boundary. Preliminary interpretations suggest that plate boundary transpression may be partitioned into distinctive structural domains, in which convergent stress is accommodated by margin-parallel thrust faulting, folding, and ridge formation within the Pacific Plate, with strike-slip faulting localized to the primary trace of the QCF. Contractional structures may be occupying zones of pre-existing crustal weakness and/or re-activated fabrics in the oceanic crust, possibly explaining strain partitioning behavior in areas with a low convergence angle (<15°).

Neogene Sediment Transport, Deposition, and Exhumation from the Southern Alaska Syntaxis to the Eastern Aleutian Subduction Zone

NASA Astrophysics Data System (ADS)

Ridgway, K. D.; Witmer, J. W.; Enkelmann, E.; Plafker, G.; Brennan, P. R.

2011-12-01

Over 5 km of Neogene sedimentary strata are well exposed in the Chugach-St. Elias Ranges within the southern Alaska syntaxis. This syntaxis forms where the Pacific-North America plate boundary changes from the northwest-trending Queen Charlotte-Fairweather transform system to the southwest-trending Alaska-Aleutian subduction zone. Active collision and subduction of the buoyant Yakutat microplate in the syntaxis results in a wide collisional zone defined by active mountain belts, extensive glaciation, and thick packages of synorogenic strata. New stratigraphic and U-Th/He thermochronologic data from Neogene synorogenic strata, named the Yakataga and Redwood Formations, provide insights on collisional tectonics, glacial erosion, and sediment transport, deposition, burial, and exhumation from the onshore Chugach and St. Elias Ranges to the exposed accretionary prism of the Aleutian trench. Stratigraphic analyses show that along the southeastern part of the syntaxis, Neogene strata are characterized by deposition in braid delta, shallow marine, and glaciomarine slope apron depositional systems that resulted in construction of a broad continental shelf. In the central part of the syntaxis, marine shelf and upper slope environments deposited thick-bedded sandstone and mudstone in a thrust belt/foreland basin system. Along the southwestern part of the syntaxis, Neogene strata were deposited in a regional submarine fan system that filled the easternmost part of the Aleutian trench. Geologic mapping of the contact between the Yakataga Formation and underlying strata along the syntaxis document an angular unconformity with maximum stratigraphic separation (> 5 km) in the central part of the syntaxis. Along strike, this unconformity becomes conformable along both the southwestern and southeastern parts of the syntaxis. The regional angular unconformity and facies transitions both point to the importance of the central part of the syntaxis in the generation and distribution of synorogenic sediment. Apatite and zircon U-Th/He thermochronologic data from granitoid and gneissic clasts in conglomerate suggest that Neogene sediments were buried no deeper than ~2 km in the central and southeastern parts of the syntaxis, and that burial temperatures did not exceed ~40-45°C. In contrast, Neogene sediment deposited by submarine fans in the Aleutian trench along the southwestern part of the syntaxis were buried at depths of 5 to 7.5 km and reached temperatures between ~120-160°C. These strata were subsequently exhumed as the trench fill was incorporated into the growing accretionary prism. Collectively, our data show that the first-order sediment pathway along a glaciated syntaxis is dynamically linked to tectonic uplift, focused glacial erosion, deposition of thick packages of glacial marine sediment, and rapid exhumation along thrust belts and accretionary prisms.

Descriptions of mineral occurrences and interpretation of mineralized rock geochemical data in the Stikine geophysical survey area, Southeastern Alaska

USGS Publications Warehouse

Taylor, Cliff D.

2003-01-01

Detailed descriptions of some of the more significant mineral occurrences in the Stikine Airborne Geophysical Survey Project Area are presented based upon site-specific examinations by the U.S. Geological Survey in May of 1998. Reconnaissance geochemical data on unmineralized igneous and sedimentary host rocks, and mineralized rocks are also presented and are accompanied by a brief analysis of geochemical signatures typical of each occurrence. Consistent with the stated goal of the geophysical survey; to stimulate exploration for polymetallic massive sulfides similar to the Greens Creek deposit, the majority of the described occurrences are possible members of a belt of Late Triassic mineral deposits that are distributed along the eastern edge of the Alexander terrane in southeastern Alaska. Many of the described occurrences in the Duncan Canal-Zarembo Island area share similarities to the Greens Creek deposit. When considered as a whole, the geology, mineralogy, and geochemistry of these occurrences help to define a transitional portion of the Late Triassic mineral belt where changes in shallow to deeper water stratigraphy and arc-like to rift-related igneous rocks are accompanied by concomitant changes in the size, morphology, and metal endowments of the mineral occurrences. As a result, Late Triassic mineral occurrences in the area appear as: 1) small, discontinuous, structurally controlled stockwork veins in mafic volcanic rocks, 2) small, irregular replacements and stratabound horizons of diagenetic semi-massive sulfides in dolostones and calcareous shales, and as 3) larger, recognizably stratiform accumulations of baritic, semi-massive to massive sulfides at and near the contact between mafic volcanic rocks and overlying sedimentary rocks. Empirical exploration guidelines for Greens Creek-like polymetallic massive sulfide deposits in southeastern Alaska include: 1) a Late Triassic volcano-sedimentary host sequence exhibiting evidence of succession from tectonic activity to quiescence (such as conglomeratic and/or mafic volcaniclastics or flows overlain by platform carbonate or shale sequences), 2) presence and proximity to Late Triassic mafic-ultramafic intrusions, 3) presence of quartz-carbonate-fuchsite altered ultramafic bodies, 4) pyritic, graphitic shales, 5) presence of barite and/or iron-manganese-rich carbonates, 6) low-iron sphalerite and antimony-rich sulfosalt minerals, 7) a geochemical signature including Fe-Zn-Pb-Cu-Ag-Au-Sb-Hg-As-Cd-Ba-Mn-Mo-Tl and the ultramafic-related suite of elements Ni-Cr-Co, and 8) a geophysical signature characterized by the coincidence of a sharp resistivity contrast with evidence for buried intrusive rocks. Critical factors for the development of larger, economic orebodies are significant thickness of pyritic, graphitic shale indicating that a locally reducing sedimentary setting was established and that accumulation of an insulating shale blank occurred, and proximity to Late Triassic aged hypabyssal mafic-ultramafic intrusive rocks.

Reconnaissance Geologic Map of the Duncan Canal-Zarembo Island Area, Southeastern Alaska

USGS Publications Warehouse

Karl, Susan M.; Haeussler, Peter J.; McCafferty, Anne E.

1999-01-01

The geologic map of the Duncan Canal-Zarembo Island area is the result of a multidisciplinary investigation of an area where an airborne geophysical survey was flown in the spring of 1997. The area was chosen for the geophysical survey because of its high mineral potential, a conclusion of the Petersburg Mineral Resource Assessment Project, conducted by the U.S. Geological Survey from 1978 to 1982. The City of Wrangell, in southeastern Alaska, the Bureau of Land Management, and the State of Alaska provided funding for the airborne geophysical survey. The geophysical data from the airborne survey were released in September 1997. The U.S. Geological Survey conducted field investigations in the spring and fall of 1998 to identify and understand the sources of the geophysical anomalies from the airborne survey. This geologic map updates the geologic maps of the same area published by David A. Brew at 1:63,360 (Brew, 1997a-m; Brew and Koch, 1997). This update is based on 3 weeks of field work, new fossil collections, and the geophysical maps released by the State of Alaska ( DGGS, Staff, and others, 1997a-o). Geologic data from outcrops, fossil ages, radiometric ages, and geochemical signatures were used to identify lithostratigraphic units. Where exposure is poor, geophysical characteristics were used to help control the boundaries of these units. No unit boundaries were drawn based on geophysics alone. The 7200 Hertz resistivity maps (DGGS, Staff, and others, 1997k-o) were particularly helpful for controlling unit boundaries, because different stratigraphic units have distinctive characteristic conductive signatures (Karl and others, 1998). Increased knowledge of unit ages, unit structure, and unit distribution, led to improved understanding of the nature of unit contacts. Northwest- to southwest-directed thrust faults, particularly on Kupreanof Island, are new discovery. Truncated faults and map patterns suggest there were at least 2 generations of thrusting, and that the thrust faults have been folded. Subsequent right-lateral strike-slip NW-SE faults, have offset thrust faults, and these in turn are offset by N-S right-lateral strike-slip faults. Our fieldwork raised as many questions as it answered, and we see this map as a progress report at a reconnaissance level. The main contributions of this map are 1) the greater distribution of Triassic rocks, 2) increased fossil age information, and 3) the identification of thrust faults within and between units.

Structural evolution of the Chugach-Prince William terrane at the hinge of the orocline in Prince William Sound, and implications for ore deposits: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1992

USGS Publications Warehouse

Haeussler, Peter J.; Nelson, Steven W.

1993-01-01

The Chugach-Prince William terrane is a Mesozoic through Tertiary accretionary complex that lies along coastal southern and southeastern Alaska. In Prince William Sound, the regional structural fabric bends about 90°, forming an orocline. Rocks at the hinge of the orocline consist of turbidites, conglomerate, and minor volcanic rocks and limestone. The structural geology in the hinge region defines a number of domains (each >15 km2) consisting of kilometer-scale tight folds. Adjacent domains may have up to a 90° difference in the strike of bedding and trend of fold axes. Four granite to tonalitic or gabbro plutons are dated or inferred to be about 35 Main age, and all were emplaced after regional folding. Base-metal sulfide mineral occurrences, barren quartz veins, and strikeslip late faults locally cut the plutons and generally strike north-south. The mineral occurrences often have a dendritic network of quartz veinlets adjacent to the mineralized zone and brecciated wall rock within the zone. Oroclinal bending, in the style of bending a bar, is consistent with the origin of the complicated domainal geometry of the structures. The Contact fault, thought by some workers to juxtapose two parts of the accretionary prism, truncates one of these 35-Ma plutons with strike-slip offset, but previous reverse motion cannot be ruled out. A magmatic source for the ore-forming fluids is consistent with the structural and mineralogical data. The north-south orientation of mineralized zones suggests that east-west extension occurred possibly during release of fluids from the plutons, which locally hydrofractured the wall rocks and allowed migration of ore-forming fluids along preexisting fractures.

Dynamic response to strike-slip tectonic control on the deposition and evolution of the Baranof Fan, Gulf of Alaska

USGS Publications Warehouse

Walton, Maureen A. L.; Gulick, Sean P. S.; Reece, Robert S.; Barth, Ginger A.; Christeson, Gail L.; VanAvendonk, Harm J.

2014-01-01

The Baranof Fan is one of three large deep-sea fans in the Gulf of Alaska, and is a key component in understanding large-scale erosion and sedimentation patterns for southeast Alaska and western Canada. We integrate new and existing seismic reflection profiles to provide new constraints on the Baranof Fan area, geometry, volume, and channel development. We estimate the fan’s area and total sediment volume to be ∼323,000 km2 and ∼301,000 km3, respectively, making it among the largest deep-sea fans in the world. We show that the Baranof Fan consists of channel-levee deposits from at least three distinct aggradational channel systems: the currently active Horizon and Mukluk channels, and the waning system we call the Baranof channel. The oldest sedimentary deposits are in the northern fan, and the youngest deposits at the fan’s southern extent; in addition, the channels seem to avulse southward consistently through time. We suggest that Baranof Fan sediment is sourced from the Coast Mountains in southeastern Alaska, transported offshore most recently via fjord to glacial sea valley conduits. Because of the translation of the Pacific plate northwest past sediment sources on the North American plate along the Queen Charlotte strike-slip fault, we suggest that new channel formation, channel beheadings, and southward-migrating channel avulsions have been influenced by regional tectonics. Using a simplified tectonic reconstruction assuming a constant Pacific plate motion of 4.4 cm/yr, we estimate that Baranof Fan deposition initiated ca. 7 Ma.

Silurian trace fossils in carbonate turbidites from the Alexander Arc of southeastern Alaska

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soja, C.M.

Early to Late Silurian (Wenlock-Ludlow) body and trace fossils from the Heceta Formation are preserved in the oldest widespread carbonates in the Alexander terrane of southeastern Alaska. They represent the earliest shelly benthos to inhabit a diversity of marine environments and are important indicators of the early stages in benthic community development within this ancient island arc. The trace fossils are significant because they add to a small but growing body of knowledge about ichnofaunas in deep-water Paleozoic carbonates. Proximal to medial carbonate turbidites yield a low-diversity suite of trace fossils that comprises five distinct types of biogenic structures. Beddingmore » planes reveal simple epichnial burrows (Planolites), cross-cutting burrows (Fucusopsis), and tiny cylindrical burrows. These and other casts, including chondrites( )-like burrow clusters, represent the feeding activities (fodinichnia) of preturbidite animals. Hypichnial burrows and rare endichnial traces reflect the activities of postturbidite animals. Broken and offset traces indicate that infaunal biota commenced burrowing before slumping and subsequent soft-sediment deformation. The abundance and density of trace fossils increases offshore in the medial turbidites associated with a decrease in the size and amount of coarse particles and with an increase in mud and preserved organic material. Although diversity levels are similar in the proximal and medial turbidite facies, they are much lower than in Paleozoic siliciclastic turbidites. This may reflect unfavorable environmental conditions for infaunal biota or paleobiogeographic isolation of the Alexander terrane during the Silurian. A greater use of trace fossils in terrane analysis will help to resolve this issue and should provide new data for reconstructing the paleogeography of circum-Pacific terranes.« less

Healing pathways: art therapy for American Indian cancer survivors.

PubMed

Warson, Elizabeth

2012-04-01

There is a paucity of research addressing quality of life factors for American Indian and Alaska Native cancer survivors. Complementary forms of therapy, such as art therapy, are beginning to address quality of life factors through the "healing" arts for cancer survivors. The purpose of this mixed methods pilot was to explore the effects of culturally relevant art interventions on stress reduction for American Indian cancer survivors and their family members. Forty-six adult participants attended one of three workshops held within two settlements of the Coharie tribe and one southeastern urban tribal center. The data collected consisted of a pretest and posttest State-Trait Personality Inventory (STPI) and artwork resulting from three directed interventions. The artwork was analyzed using qualitative coding methods; however, the scores from the STPI were inconclusive because the inventory was determined to be culturally biased. While statistical significance was not achieved, the findings from qualitative coding reinforced a native concept of wellness focusing on the complex interaction between mind, body, spirit, and context. This pilot study also demonstrated how a community-driven approach was instrumental in the development of the overall workshop format. An expansion of the pilot study is also presented with preliminary results available in 2012.

Distribution and spawning dynamics of capelin (Mallotus villosus) in Glacier Bay, Alaska: A cold water refugium

USGS Publications Warehouse

Arimitsu, Mayumi L.; Piatt, John F.; Litzow, Michael A.; Abookire, Alisa A.; Romano, Marc D.; Robards, Martin D.

2008-01-01

Pacific capelin (Mallotus villosus) populations declined dramatically in the Northeastern Pacific following ocean warming after the regime shift of 1977, but little is known about the cause of the decline or the functional relationships between capelin and their environment. We assessed the distribution and abundance of spawning, non-spawning adult and larval capelin in Glacier Bay, an estuarine fjord system in southeastern Alaska. We used principal components analysis to analyze midwater trawl and beach seine data collected between 1999 and 2004 with respect to oceanographic data and other measures of physical habitat including proximity to tidewater glaciers and potential spawning habitat. Both spawning and non-spawning adult Pacific capelin were more likely to occur in areas closest to tidewater glaciers, and those areas were distinguished by lower temperature, higher turbidity, higher dissolved oxygen and lower chlorophyll a levels when compared with other areas of the bay. The distribution of larval Pacific capelin was not sensitive to glacial influence. Pre-spawning females collected farther from tidewater glaciers were at a lower maturity state than those sampled closer to tidewater glaciers, and the geographic variation in the onset of spawning is likely the result of differences in the marine habitat among sub-areas of Glacier Bay. Proximity to cold water in Glacier Bay may have provided a refuge for capelin during the recent warm years in the Gulf of Alaska.

Population trends of Alaskan seabirds

USGS Publications Warehouse

Hatch, Scott A.

1993-01-01

Ornithology in Alaska formally began with the observations of Georg Wilhelm Steller during Vitus Bering's voyage of discovery in 1741. Steller's journal makes brief mention of various seabird species he encountered during his travels in the Gulf of Alaska and Aleutian Islands (Frost and Engel 1988). For more than 100 years following Steller, the Russian-American Company was active in commercial fur harvesting throughout southern coastal Alaska, but this period saw little contribution to a scientific understanding of the region's avifauna. With the purchase of Alaska by the United States in 1867, a period of American exploration began that included significant work by pioneering naturalists such as Dall (1873, 1874), Elliot (1881), Nelson (1883), and Turner (1885, 1886). While this activity established a comprehensive list and general knowledge of the distribution of seabird species occurring in Alaska, early observers provided no quantitative estimates of abundance for any colony or region.The observations of Heath (1915) and Willett (1912, 1915, 1917) at two locations in southeastern Alaska are notable for including the first numerical estimates of any seabird populations for comparison with recent data. Willett's (1912, 1915) estimates of 13 species are given in Table 1 with results from a 1976 Survey at Forrester Island (DeGange et al. 1977) and a 1981 survey at St. Lazaria Island (Nelson et al 1982). In the aggregate, seabird numbers appeared to increase dramatically at both sites, but the differences may be largely artificial. Because Willett (1915) did not employ rigorous sampling methods, DeGange et al. (1977) surmised that he grossly underestimated the populations of burrowing species such as storm-petrels, Cassin's Auklets. and Rhinoceros Aulkets. Nelson et al. (1982) offered a similar interpretation of total storm-petrel numbers at St. Lazaria, but felt that a shift in the species ratio of Leach's and Fork-tailed Storm-Petrels had likely occurred. It seems reasonably certain that real changes in some of the open-nesters like Common Murres (down at Forrester Island, up at St. Lazaria) and Glaucous-winged and Herring Gulls (absent or down at both sites) have occurred since Willet's time.

The Cannery Formation--Devonian to Early Permian arc-marginal deposits within the Alexander Terrane, Southeastern Alaska

USGS Publications Warehouse

Karl, Susan M.; Layer, Paul W.; Harris, Anita G.; Haeussler, Peter J.; Murchey, Benita L.

2011-01-01

The Cannery Formation consists of green, red, and gray ribbon chert, siliceous siltstone, graywacke-chert turbidites, and volcaniclastic sandstone. Because it contains early Permian fossils at and near its type area in Cannery Cove, on Admiralty Island in southeastern Alaska, the formation was originally defined as a Permian stratigraphic unit. Similar rocks exposed in Windfall Harbor on Admiralty Island contain early Permian bryozoans and brachiopods, as well as Mississippian through Permian radiolarians. Black and green bedded chert with subordinate lenses of limestone, basalt, and graywacke near Kake on Kupreanof Island was initially correlated with the Cannery Formation on the basis of similar lithology but was later determined to contain Late Devonian conodonts. Permian conglomerate in Keku Strait contains chert cobbles inferred to be derived from the Cannery Formation that yielded Devonian and Mississippian radiolarians. On the basis of fossils recovered from a limestone lens near Kake and chert cobbles in the Keku Strait area, the age of the Cannery Formation was revised to Devonian and Mississippian, but this revision excludes rocks in the type locality, in addition to excluding bedded chert on Kupreanof Island east of Kake that contains radiolarians of Late Pennsylvanian and early Permian age. The black chert near Kake that yielded Late Devonian conodonts is nearly contemporaneous with black chert interbedded with limestone that also contains Late Devonian conodonts in the Saginaw Bay Formation on Kuiu Island. The chert cobbles in the conglomerate in Keku Strait may be derived from either the Cannery Formation or the Saginaw Bay Formation and need not restrict the age of the Cannery Formation, regardless of their source. The minimum age of the Cannery Formation on both Admiralty Island and Kupreanof Island is constrained by the stratigraphically overlying fossiliferous Pybus Formation, of late early and early late Permian age. Because bedded radiolarian cherts on both Admiralty and Kupreanof Islands contain radiolarians as young as Permian, the age of the Cannery Formation is herein extended to Late Devonian through early Permian, to include the early Permian rocks exposed in its type locality. The Cannery Formation is folded and faulted, and its stratigraphic thickness is unknown but inferred to be several hundred meters. The Cannery Formation represents an extended period of marine deposition in moderately deep water, with slow rates of deposition and limited clastic input during Devonian through Pennsylvanian time and increasing argillaceous, volcaniclastic, and bioclastic input during the Permian. The Cannery Formation comprises upper Paleozoic rocks in the Alexander terrane of southeastern Alaska. In the pre-Permian upper Paleozoic, the tectonic setting of the Alexander terrane consisted of two or more evolved oceanic arcs. The lower Permian section is represented by a distinctive suite of rocks in the Alexander terrane, which includes sedimentary and volcanic rocks containing early Permian fossils, metamorphosed rocks with early Permian cooling ages, and intrusive rocks with early Permian cooling ages, that form discrete northwest-trending belts. After restoration of 180 km of dextral displacement of the Chilkat-Chichagof block on the Chatham Strait Fault, these belts consist, from northeast to southwest, of (1) bedded chert, siliceous argillite, volcaniclastic turbidites, pillow basalt, and limestone of the Cannery Formation and the Porcupine Slate of Gilbert and others (1987); (2) greenschist-facies Paleozoic metasedimentary and metavolcanic rocks that have Permian cooling ages; (3) silty limestone and calcareous argillite interbedded with pillow basalt and volcaniclastic rocks of the Halleck Formation and the William Henry Bay area; and (4) intermediate-composition and syenitic plutons. These belts correspond to components of an accretionary complex, contemporary metamorphic rocks, forearc-basin deposits,

An integrated data model to estimate spatiotemporal occupancy, abundance, and colonization dynamics

USGS Publications Warehouse

Williams, Perry J.; Hooten, Mevin B.; Womble, Jamie N.; Esslinger, George G.; Bower, Michael R.; Hefley, Trevor J.

2017-01-01

Ecological invasions and colonizations occur dynamically through space and time. Estimating the distribution and abundance of colonizing species is critical for efficient management or conservation. We describe a statistical framework for simultaneously estimating spatiotemporal occupancy and abundance dynamics of a colonizing species. Our method accounts for several issues that are common when modeling spatiotemporal ecological data including multiple levels of detection probability, multiple data sources, and computational limitations that occur when making fine-scale inference over a large spatiotemporal domain. We apply the model to estimate the colonization dynamics of sea otters (Enhydra lutris) in Glacier Bay, in southeastern Alaska.

Genetic links among fluid cycling, vein formation, regional deformation, and plutonism in the Juneau gold belt, southeastern Alaska

USGS Publications Warehouse

Miller, Lance D.; Goldfarb, Richard J.; Gehrels, George E.; Snee, Lawrence W.

1994-01-01

Gold-bearing quartz vein systems in the Juneau gold belt formed within a 160-km- long by 5- to 8-km-wide zone along the western margin of the Coast Mountains, Alaska. Vein systems are spatially associated with shear zones adjacent to terrane-bounding, mid-Cretaceous thrust faults. Analysis of vein orientations and sense of shear data define a stress configuration with greatest and least principal axes oriented subhorizontally with northeast-southwest trends and subverticaly, respectively. This local stress configuration is compatible with the far-field plate configuration during Eocene time. Isotopic ages of vein formation indicate that fluid cycling occurred between 56.5 and ≥52.8 Ma, and are consistent with a genetic link between veining and a change in plate motion in early Eocene time. Veining was also synchronous with the latter stages of rapid exhumation and voluminous plutonism immediately inboard of the gold belt. We propose a model in which interacting tectonic events facilitated fault-valve action and vein development along now-exhumed shear zones.

The Application of Methane Clumped Isotope Measurements to Determine the Source of Large Methane Seeps in Alaskan Lakes

NASA Astrophysics Data System (ADS)

Douglas, P. M.; Stolper, D. A.; Eiler, J. M.; Sessions, A. L.; Walter Anthony, K. M.

2014-12-01

Natural methane emissions from the Arctic present an important potential feedback to global warming. Arctic methane emissions may come from either active microbial sources or from deep fossil reservoirs released by the thawing of permafrost and melting of glaciers. It is often difficult to distinguish between and quantify contributions from these methane sources based on stable isotope data. Analyses of methane clumped isotopes (isotopologues with two or more rare isotopes such as 13CH3D) can complement traditional stable isotope-based classifications of methane sources. This is because clumped isotope abundances (for isotopically equilibrated systems) are a function of temperature and can be used to identify pathways of methane generation. Additionally, distinctive effects of mixing on clumped isotope abundances make this analysis valuable for determining the origins of mixed gasses. We find large variability in clumped isotope compositions of methane from seeps in several lakes, including thermokarst lakes, across Alaska. At Lake Sukok in northern Alaska we observe the emission of dominantly thermogenic methane, with a formation temperature of at least 100° C. At several other lakes we find evidence for mixing between thermogenic methane and biogenic methane that forms in low-temperature isotopic equilibrium. For example, at Eyak Lake in southeastern Alaska, analysis of three methane samples results in a distinctive isotopic mixing line between a high-temperature end-member that formed between 100-170° C, and a biogenic end-member that formed in isotopic equilibrium between 0-20° C. In this respect, biogenic methane in these lakes resembles observations from marine gas seeps, oil degradation, and sub-surface aquifers. Interestingly, at Goldstream Lake in interior Alaska, methane with strongly depleted clumped-isotope abundances, indicative of disequilibrium gas formation, is found, similar to observations from methanogen culture experiments.

Elemental and Mineralogical Analysis of Silt Fraction from Site U1420, IODP Expedition 341

NASA Astrophysics Data System (ADS)

Salinas, J. K.; Jaeger, J. M.; Penkrot, M. L.

2016-12-01

In southeastern Alaska, the Chugach-St. Elias Mountains - the world's highest coastal mountain range - exhibit extreme topography due to the collision and subduction of the Yakutat microplate beneath the North American plate. The St. Elias orogen is younger than 30 Ma, with mountain building having occurred during a period of enhanced glacial erosion when erosive ice streams delivered sediment into the Gulf of Alaska. Integrated Ocean Drilling Program Expedition 341 set out to investigate the relationship between mountain building and glacial dynamics in the Gulf of Alaska. Sediment cores from site U1420 were collected, within the Bering trough, just offshore of the Bering Glacier. Analysis of Bering Trough seismic profiles demonstrates an evolution from tectonically-controlled to depositionally-controlled continental margin strata formation (Worthington et al., 2010). The goal of this study is to investigate the provenance of the silt-sized fraction (15-63 μm) of U1420 sediments across this transition in seismic facies using mineralogy and elemental geochemical analyses. XRD mineralogical analysis shows consistent downhole mineralogy with minor variations in relative peak intensities. Elemental ICP-MS geochemical analysis reveal concentrations of both major and trace elements to be very well constrained, with all major (Al, Ca, Fe, Mg, and Ti) and trace elemental data (Ce, Cr, Ga, La, Rb, Sc, Sr, Th, and Y) only varying downhole by few percent/ppm. Both the consistent downhole mineralogy and elemental data suggest that the provenance of the silt-sized sediment deposited offshore has not changed since initial deposition (<0.7 Ma). Comparison with onshore bedrock geochemistry and surface samples from the modern Gulf of Alaska indicate that U1420 silt is similar in composition to modern regional sediment sources and is a mixture of the different bedrock lithologies within the modern Bering Glacier drainage.

Molecular status of the dusky Canada goose (Branta canadensis occidentalis): A genetic assessment of a translocation effort

USGS Publications Warehouse

Talbot, S.L.; Pearce, J.M.; Pierson, Barbara J.; Derksen, D.V.; Scribner, K.T.

2003-01-01

Until recently, the dusky Canada goose (Branta canadensis occidentalis) was managed as one breeding population from the Copper River Delta (CRD), Alaska. Population numbers on the CRD have declined precipitously over the last three decades, due in part to changes in habitat. In 1981, a pair of Canada geese, presumably B.c. occidentalis, was reported nesting on Middleton Island (MID), in the Gulf of Alaska. Numbers of Canada geese on the island increased in the decade subsequent to a translocation of geese from CRD to MID, but it is unclear whether the increase is attributable to the translocation effort. We used genetic data derived from three classes of genetic markers to clarify relationships of Canada geese breeding in south-coastal Alaska. Geese were sampled from 5 populations: CRD, MID, Anchorage (ANC), Admiralty Island (ADM) in southeastern Alaska, and Green Island (GRN) in Prince William Sound (PWS). Mitochondrial DNA analyses demonstrate Canada geese from MID are nearly monomorphic for a unique haplotype fixed on GRN but not found in CRD or any other breeding population. Furthermore, nuclear markers consistently cluster MID with GRN to the exclusion of CRD. We suggest the current population on MID is not derived from birds translocated from CRD, but rather that MID was most likely colonised by birds inhabiting other island habitats within the PWS. Furthermore, since geese from the CRD share mtDNA haplotypes with geese from other breeding locales, they apparently share recent common ancestry and/or gene flow with populations representing other subspecies. Our genetic data raise questions about the validity of current management units of Canada geese.

Quantifying the Availability of Tidewater Glacial Ice as Habitat for Harbor Seals in a Tidewater Glacial Fjord in Alaska Using Object-Based Image Analysis of Airborne Visible Imagery

NASA Astrophysics Data System (ADS)

Prakash, A.; Haselwimmer, C. E.; Gens, R.; Womble, J. N.; Ver Hoef, J.

2013-12-01

Tidewater glaciers are prominent landscape features that play a significant role in landscape and ecosystem processes along the southeastern and southcentral coasts of Alaska. Tidewater glaciers calve large icebergs that serve as an important substrate for harbor seals (Phoca vitulina richardii) for resting, pupping, nursing young, molting, and avoiding predators. Many of the tidewater glaciers in Alaska are retreating, which may influence harbor seal populations. Our objectives are to investigate the relationship between ice conditions and harbor seal distributions, which are poorly understood, in John's Hopkins Inlet, Glacier Bay National Park, Alaska, using a combination of airborne remote sensing and statistical modeling techniques. We present an overview of some results from Object-Based Image Analysis (OBIA) for classification of a time series of very high spatial resolution (4 cm pixels) airborne imagery acquired over John's Hopkins Inlet during the harbor seal pupping season in June and during the molting season in August from 2007 - 2012. Using OBIA we have developed a workflow to automate processing of the large volumes (~1250 images/survey) of airborne visible imagery for 1) classification of ice products (e.g. percent ice cover, percent brash ice, percent ice bergs) at a range of scales, and 2) quantitative determination of ice morphological properties such as iceberg size, roundness, and texture that are not found in traditional per-pixel classification approaches. These ice classifications and morphological variables are then used in statistical models to assess relationships with harbor seal abundance and distribution. Ultimately, understanding these relationships may provide novel perspectives on the spatial and temporal variation of harbor seals in tidewater glacial fjords.

Environment and science: Chapter 9

USGS Publications Warehouse

Pearce, John; Talbot, Sandra L.

2017-01-01

Alaska is part of an international circumpolar North, which makes the United States an Arctic nation. Alaska is a place of Indigenous ingenuity and adaptation, a place where environmental extremes challenge the ways of living. In its more recent history, Alaska has been a place of resources and influx-a land known best for what it provides. This frontier persona, with its sourdoughs and prospectors, has not been easily shed, but Alaska today is pivotal because it represents America's North and a complex and changing Arctic. North: Finding Place in Alaska explores the state's various facets through exhibitions and artifacts at the Anchorage Museum and the words of a diverse selection of writers, curators, historians, anthropologists, and artists. From romantic landscapes by Rockwell Kent and Thomas Hill, to the art and spirituality of Alaska's Native peoples represented by a bentwood feast dish and a uniquely carved hook for catching halibut, this collection examines connections throughout the circumpolar North. No longer as remote as once thought, Alaska serves as a narrative for our future.

Environmental Impact Statement for the Modernization and Enhancement of Ranges, Airspace, and Training Areas in the Joint Pacific Alaska Range Complex in Alaska. Volume 2 - Appendices A through L

DTIC Science & Technology

2013-06-01

enhanC;enwnlswonld ~nahle reoJ istk. jolll l training artd ta.~ti 1g to sup pori omergi ng tedwolo~ttt.», respond lo recent balllefiold...The military uses the JPARC to conduct testing and training and lo support joint exercises and mission rehearsals. The JPARC was originally developed...68th Ave. and Elmore Rd.) 4477 Pike’s Landing.Road Anchorage, Alaska 99507-2599 Fairbanks, Alaska 99709 I 0 a.m. to noon and I :00 lo 5:00p.m. I 0

Alaska geology revealed

USGS Publications Warehouse

Wilson, Frederic H.; Labay, Keith A.

2016-11-09

This map shows the generalized geology of Alaska, which helps us to understand where potential mineral deposits and energy resources might be found, define ecosystems, and ultimately, teach us about the earth history of the State. Rock units are grouped in very broad categories on the basis of age and general rock type. A much more detailed and fully referenced presentation of the geology of Alaska is available in the Geologic Map of Alaska (http://dx.doi.org/10.3133/sim3340). This product represents the simplification of thousands of individual rock units into just 39 broad groups. Even with this generalization, the sheer complexity of Alaskan geology remains evident.

Publications - PIR 2002-1C | Alaska Division of Geological & Geophysical

Science.gov Websites

fortymile_eaglea1_surficial Shapefile 3.3 M Metadata - Read me Keywords Alaska, State of; Alluvial Deposits; Bison Fossils ; Boundary (Place); Caribou Fossils; Cenozoic; Colluvial Deposits; Complex Deposits; Cretaceous; Devonian ; Fortymile Mining District; Fortymile River; Geologic Map; Geology; Glacial Deposits; Holocene; Horse Fossils

Speciation and Trends of Organic Nitrogen in Southeastern U.S. Fine Particulate Matter (PM2.5)

EPA Science Inventory

Dissolved free amino acids (FAA; amino acids present in a dissolvable state) and combined AA (CAA; amino acids present in peptides, proteins, or humic complexes) in fine aerosols (PM) are investigated at a semi-urban site in the southeastern US. Detection of native (chemically un...

Equilibrium Moisture Content of Common Fine Fuels in Southeastern Forests

Treesearch

W.H. Blackmarr

1971-01-01

Nine different kinds of forest litter found in ground fuel complexes of southeastern forests were subjected to step-wise changes in relative humidity to determine their equilibrium moisture content (EMC) at different levels of relative humidity. The adsorption and desorption EMC curves for these fuels exhibited the typical hysteresis loop...

Alaska: A twenty-first-century petroleum province

USGS Publications Warehouse

Bird, K.J.

2001-01-01

Alaska, the least explored of all United States regions, is estimated to contain approximately 40% of total U.S. undiscovered, technically recoverable oil and natural-gas resources, based on the most recent U.S. Department of the Interior (U.S. Geological Survey and Minerals Management Service) estimates. Northern Alaska, including the North Slope and adjacent Beaufort and Chukchi continental shelves, holds the lion's share of the total Alaskan endowment of more than 30 billion barrels (4.8 billion m3) of oil and natural-gas liquids plus nearly 200 trillion cubic feet (5.7 trillion m3) of natural gas. This geologically complex region includes prospective strata within passive-margin, rift, and foreland-basin sequences. Multiple source-rock zones have charged several regionally extensive petroleum systems. Extensional and compressional structures provide ample structural objectives. In addition, recent emphasis on stratigraphic traps has demonstrated significant resource potential in shelf and turbidite systems in Jurassic to Tertiary strata. Despite robust potential, northern Alaska remains a risky exploration frontier - a nexus of geologic complexity, harsh economic conditions, and volatile policy issues. Its role as a major petroleum province in this century will depend on continued technological innovations, not only in exploration and drilling operations, but also in development of huge, currently unmarketable natural-gas resources. Ultimately, policy decisions will determine whether exploration of arctic Alaska will proceed.

The Tlingit Indians of Southeastern Alaska: Social Studies Unit for Elementary Grades. Teacher's Manual [And] Kiksadi Dog Salmon Legend [And] Halibut Fishing [And] How Raven Stole the Light: A Radio Play [And] Raven, The Old Woman of the Tides, and the Sea Urchins: A Puppet Play [And] Raven and the Fog Woman [And] The Legendary Adventures of Raven [And] A Tlingit Uncle and His Nephews [And] Three Brothers [And] Lingit Aanee....

ERIC Educational Resources Information Center

Partnow, Patricia H.; And Others

Part of a series designed to introduce the culture of the Alaskan Indians to elementary school students, the unit contains materials related to seasonal Tlingit activities and a guide for elementary classroom teachers to implement the student materials. The guide describes the format of the unit, suggests activities, lists resource materials, and…

An integrated data model to estimate spatiotemporal occupancy, abundance, and colonization dynamics.

PubMed

Williams, Perry J; Hooten, Mevin B; Womble, Jamie N; Esslinger, George G; Bower, Michael R; Hefley, Trevor J

2017-02-01

Ecological invasions and colonizations occur dynamically through space and time. Estimating the distribution and abundance of colonizing species is critical for efficient management or conservation. We describe a statistical framework for simultaneously estimating spatiotemporal occupancy and abundance dynamics of a colonizing species. Our method accounts for several issues that are common when modeling spatiotemporal ecological data including multiple levels of detection probability, multiple data sources, and computational limitations that occur when making fine-scale inference over a large spatiotemporal domain. We apply the model to estimate the colonization dynamics of sea otters (Enhydra lutris) in Glacier Bay, in southeastern Alaska. © 2016 by the Ecological Society of America.

Rare earth element contents and multiple mantle sources of the transform-related Mount Edgecumbe basalts, southeastern Alaska

USGS Publications Warehouse

Riehle, J.R.; Budahn, J.R.; Lanphere, M.A.; Brew, D.A.

1994-01-01

Pleistocene basalt of the Mount Edgecumbe volcanic field (MEF) is subdivided into a plagioclase type and an olivine type. Th/La ratios of plagioclase basalt are similar to those of mid-ocean-ridge basalt (MORB), whereas those of olivine basalt are of continental affinity. Rare earth element (REE) contents of the olivine basalt, which resemble those of transitional MORB, are modelled by 10-15% partial melting of fertile spinel-plagioclase lherzolite followed by removal of 8-13% olivine. It is concluded that olivine basalt originated in subcontinental spinel lherzolite and that plagioclase basalt may have originated in suboceanic lithosphere of the Pacific plate. -from Authors

Preliminary volcano-hazard assessment for Mount Spurr Volcano, Alaska

USGS Publications Warehouse

Waythomas, Christopher F.; Nye, Christopher J.

2001-01-01

Mount Spurr volcano is an ice- and snow-covered stratovolcano complex located in the north-central Cook Inlet region about 100 kilometers west of Anchorage, Alaska. Mount Spurr volcano consists of a breached stratovolcano, a lava dome at the summit of Mount Spurr, and Crater Peak vent, a small stratocone on the south flank of Mount Spurr volcano. Historical eruptions of Crater Peak occurred in 1953 and 1992. These eruptions were relatively small but explosive, and they dispersed volcanic ash over areas of interior, south-central, and southeastern Alaska. Individual ash clouds produced by the 1992 eruption drifted east, north, and south. Within a few days of the eruption, the south-moving ash cloud was detected over the North Atlantic. Pyroclastic flows that descended the south flank of Crater Peak during both historical eruptions initiated volcanic-debris flows or lahars that formed temporary debris dams across the Chakachatna River, the principal drainage south of Crater Peak. Prehistoric eruptions of Crater Peak and Mount Spurr generated clouds of volcanic ash, pyroclastic flows, and lahars that extended to the volcano flanks and beyond. A flank collapse on the southeast side of Mount Spurr generated a large debris avalanche that flowed about 20 kilometers beyond the volcano into the Chakachatna River valley. The debris-avalanche deposit probably formed a large, temporary debris dam across the Chakachatna River. The distribution and thickness of volcanic-ash deposits from Mount Spurr volcano in the Cook Inlet region indicate that volcanic-ash clouds from most prehistoric eruptions were as voluminous as those produced by the 1953 and 1992 eruptions. Clouds of volcanic ash emitted from the active vent, Crater Peak, would be a major hazard to all aircraft using Ted Stevens Anchorage International Airport and other local airports and, depending on wind direction, could drift a considerable distance beyond the volcano. Ash fall from future eruptions could disrupt many types of economic and social activities, including oil and gas operations and shipping activities in the Cook Inlet area. Eruptions of Crater Peak could involve significant amounts of ice and snow that would lead to the formation of large lahars, formation of volcanic debris dams, and downstream flooding. The greatest hazards in order of importance are described below and shown on plate 1.

Catalog of the historically active volcanoes of Alaska

USGS Publications Warehouse

Miller, T.P.; McGimsey, R.G.; Richter, D.H.; Riehle, J.R.; Nye, C.J.; Yount, M.E.; Dumoulin, Julie A.

1998-01-01

Alaska hosts within its borders over 80 major volcanic centers that have erupted during Holocene time (< 10,000 years). At least 29 of these volcanic centers (table 1) had historical eruptions and 12 additional volcanic centers may have had historical eruptions. Historical in Alaska generally means the period since 1760 when explorers, travelers, and inhabitants kept written records. These 41 volcanic centers have been the source for >265 eruptions reported from Alaska volcanoes. With the exception of Wrangell volcano, all the centers are in, or near, the Aleutian volcanic arc, which extends 2500 km from Hayes volcano 145 km west of Anchorage in the Alaska-Aleutian Range to Buldir Island in the western Aleutian Islands (fig. 1). The volcanic arc, a subduction-related feature associated with underthrusting of the Pacific plate beneath the North American plate is divided between oceanic island arc and continental margin segments, the boundary occurring at about 165° W longitude (fig. 1). An additional 7 volcanic centers in the Aleutian arc (table 2; fig. 1 A) have active fumarole fields but no reported historical eruptions.This report discusses the location, physiography and structure, eruptive history, and geology of those volcanoes in Alaska that have experienced one or more eruptions that have been recorded in the written history (i.e., in historical time). It is part of the group of catalogs entitled Catalogue of Active Volcanoes of the World published beginning in 1951 under the auspices of the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI). A knowledge of the information contained in such catalogs aids in understanding the type and scale of activity that might be expected during a particular eruption, the hazards the eruption may pose, and even the prediction of eruptions. The catalog will thus be of value not only to the inhabitants of Alaska but to government agencies concerned with emergency response, air traffic operations, and weather, as well as to industry and scientists. The combination of the hazard posed by volcanic ash to jet aircraft and the heavy use of international air routes located parallel to, and on either side of, the Aleutian volcanic arc means that even remote volcanoes in Alaska now pose significant hazards to life and property.Although this report is concerned with historical eruptions from Alaskan volcanoes, other volcanoes in Alaska have erupted in the past 10,000 years and might therefore be expected to erupt again. Several Holocene volcanic centers in the Aleutian arc have no reported historical activity. Elsewhere in Alaska the Bering Sea basalt fields cover large areas of the Yukon Delta, Seward Peninsula, and several of the islands of the Bering Sea. Holocene centers also occur in the Wrangell Mountains and in isolated occurrences in the interior and southeastern Alaska. Eruptions from these centers have occurred within the past several hundred years but none were transcribed in the written record. Moodie and others (1992), however, report oral traditions among the Northern Athapaskan Indians of the southwestern Yukon Territory that may record the second and younger deposition of the White River Ash circa A.D. 720. This lobe of the White River Ash was deposited during the paroxysmal eruption of Churchill volcano in the Wrangell Mountains of eastcentral Alaska (McGimsey and others, 1992; Richter and others, 1995).

Alaska High School Students Integrate Forest Ecology, Glacial Landscape Dynamics, and Human Maritime History in a Field Mapping Course at Cape Decision Lighthouse, Kuiu Island, Southeast Alaska

NASA Astrophysics Data System (ADS)

Connor, C. L.; Carstensen, R.; Domke, L.; Donohoe, S.; Clark, A.; Cordero, D.; Otsea, C.; Hakala, M.; Parks, R.; Lanwermeyer, S.; Discover Design Research (Ddr)

2010-12-01

Alaskan 10th and 11th graders earned college credit at Cape Decision Lighthouse as part of a 12-day, summer field research experience. Students and faculty flew to the southern tip of Kuiu Island located 388 km south of Juneau. Kuiu is the largest uninhabited island in southeastern Alaska. This field-based, introduction-to-research course was designed to engage students in the sciences and give them skills in technology, engineering, and mathematics. Two faculty, a forest naturalist and a geologist, introduced the students to the use of hand held GPS receivers, GIS map making, field note-taking and documentary photography, increment borer use, and soil studies techniques. Daily surveys across the region, provided onsite opportunities for the faculty to introduce the high schoolers to the many dimensions of forest ecology and plant succession. Students collected tree cores using increment borers to determine “release dates” providing clues to past wind disturbance. They discovered the influence of landscape change on the forest by digging soil pits and through guided interpretation of bedrock outcrops. The students learned about glacially influenced hydrology in forested wetlands during peat bog hikes. They developed an eye for geomorphic features along coastal traverses, which helped them to understand the influences of uplift through faulting and isostatic rebound in this tectonically active and once glaciated area. They surveyed forest patches to distinguish between regions of declining yellow-cedar from wind-disturbed spruce forests. The students encountered large volumes of primarily plastic marine debris, now stratified by density and wave energy, throughout the southern Kuiu intertidal zone. They traced pre-European Alaska Native subsistence use of the area, 19th and 20th century Alaska Territorial Maritime history, and learned about the 21st century radio tracking of over 10,000 commercial vessels by the Marine Exchange of Alaska from its many stations that include the Cape Decision Lighthouse. The students produced preliminary maps in ArcGIS and journals in Indesign, using laptops in a field camp GIS lab, powered by solar cells, at the Cape Decision Lighthouse. They presented the results of their research at a university convened Discover Design Research Forum in Juneau, at the end of their field work. The course was co-sponsored by the University Alaska Southeast, the Juneau Economic Development Council, and the Cape Decision Lighthouse Society.

Bird-habitat relationships in riparian communities of southeastern Wyoming

Treesearch

Deborah M. Finch

1987-01-01

Bird-habitat relationships along a riparian gradient in southeastern Wyoming were examined from 1982 to 1984. Breeding birds were spot-mapped on ten study grids established over an elevational cline of 933 m. Habitat analyses indicated significant trends of decreasing vegetational complexity from low to high elevations, with declines in number of habitat layers, and...

Glaciers of North America - Glaciers of Alaska

USGS Publications Warehouse

Molnia, Bruce F.

2008-01-01

Glaciers cover about 75,000 km2 of Alaska, about 5 percent of the State. The glaciers are situated on 11 mountain ranges, 1 large island, an island chain, and 1 archipelago and range in elevation from more than 6,000 m to below sea level. Alaska's glaciers extend geographically from the far southeast at lat 55 deg 19'N., long 130 deg 05'W., about 100 kilometers east of Ketchikan, to the far southwest at Kiska Island at lat 52 deg 05'N., long 177 deg 35'E., in the Aleutian Islands, and as far north as lat 69 deg 20'N., long 143 deg 45'W., in the Brooks Range. During the 'Little Ice Age', Alaska's glaciers expanded significantly. The total area and volume of glaciers in Alaska continue to decrease, as they have been doing since the 18th century. Of the 153 1:250,000-scale topographic maps that cover the State of Alaska, 63 sheets show glaciers. Although the number of extant glaciers has never been systematically counted and is thus unknown, the total probably is greater than 100,000. Only about 600 glaciers (about 1 percent) have been officially named by the U.S. Board on Geographic Names (BGN). There are about 60 active and former tidewater glaciers in Alaska. Within the glacierized mountain ranges of southeastern Alaska and western Canada, 205 glaciers (75 percent in Alaska) have a history of surging. In the same region, at least 53 present and 7 former large ice-dammed lakes have produced jokulhlaups (glacier-outburst floods). Ice-capped volcanoes on mainland Alaska and in the Aleutian Islands have a potential for jokulhlaups caused by subglacier volcanic and geothermal activity. Because of the size of the area covered by glaciers and the lack of large-scale maps of the glacierized areas, satellite imagery and other satellite remote-sensing data are the only practical means of monitoring regional changes in the area and volume of Alaska's glaciers in response to short- and long-term changes in the maritime and continental climates of the State. A review of the literature for each of the 11 mountain ranges, the large island, the island chain, and the archipelago was conducted to determine both the individual and the regional status of Alaskan glaciers and to characterize changes in thickness and terminus position of representative glaciers in each mountain range or island group. In many areas, observations used for determining changes date from the late 18th or early 19th century. Temperature records at all Alaskan meteorological recording stations document a 20th century warming trend. Therefore, characterizing the response of Alaska's glaciers to changing climate helps to quantify potential sea-level rise from past, present, and future melting of glacier ice (deglaciation of the 14 glacierized regions of Alaska), understand present and future hydrological changes, and define impacts on ecosystems that are responding to deglacierization. Many different types of data were scrutinized to determine baselines and to assess the magnitude of glacier change. These data include the following: published descriptions of glaciers (1794-2000), especially the comprehensive research by Field (1975a) and his colleagues in the Alaska part of Mountain Glaciers of the Northern Hemisphere, aerial photography (since 1926), ground photography (since 1884), airborne radar (1981-91), satellite radar (1978-98), space photography (1984-94), multispectral satellite imagery (since 1972), aerial reconnaissance and field observations made by many scientists during the past several decades, and various types of proxy data. The published and unpublished data available for each glacierized region and individual glacier varied significantly. Geospatial analysis of digitized U.S. Geological Survey (USGS) topographic maps is used to statistically define selected glaciological parameters in the eastern part of the Alaska Range. The analysis determined that every mountain range and island group investigated can be characterized by significant glac

KSC01kodi071

NASA Image and Video Library

2001-08-08

KODIAK ISLAND, Alaska -- Technicians transport the Sapphire payload at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5 p.m. to 7 p.m. p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01KODI057

NASA Image and Video Library

2001-05-31

KODIAK ISLAND, Alaska -- Technicians prepare the Athena I launch vehicle for flight at Kodiak Island, Alaska, as processing for the launch of Kodiak Star proceeds. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

Map and table showing isotopic age data in Alaska

USGS Publications Warehouse

Wilson, Frederic H.; Shew, Nora B.; DuBois, G.D.

1994-01-01

The source of the data reported here is a compilation of radiometric ages maintained in conjunction with the Alaska Mineral Resource Assessment Program (AMRAP) studies for Alaska. The symbol shape plotted at each location is coded for rock type, whether igneous, metamorphic, or other; the color of the symbol shows the geologic era or period for the Sample(s) at each locale. A list of references for each quadrangle is given to enable the user to find specific information including analytical data for each sample dated within a particular quadrangle. At the scale of this map, the very large number of Samples and the clustering of the samples in limited areas prevented the showing of individual sample numbers on the map.Synthesis and interpretation of any data set requires the user to evaluate the reliability or value of each component of the data set with respect to his or her intended use of the data. For geochronological data, this evaluation must be based on both analytical and geological criteria. Most age determinations are published with calculated estimates of analytical precision, Replicate analyses are infrequently performed; therefore, reported analytical precision is based on estimates of the precision of various components of the analysis and often on an intuitive factor to cover components that may have not been considered. Analytical accuracy is somewhat more difficult to determine; it is not only dependent on the actual measurement, it is also concerned with uncertainties in decay and abundance constants, uncertainties in the isotopic composition and size of the tracer for conventional K-Ar ages, and uncertainties in the Original isotopic composition of the sample, Geologic accuracy of a date is Variable; the interpretation of the meaning of an age determination, is important in the evaluation of its geologic accuracy. Potassium-argon, rubidium-strontium, and uranium-lead age determinations on a single sample can differ widely yet none or all may be wrong Given that the basic Conditions of each dating method were met, each method determines an age based on the equilibration of its particular isotopic system, yet these are different systems and they react to heat, pressure, and recrystallization in different ways.This map is a compilation and not a synthesis or interpretation. Its purpose is to help the user determine the dating coverage of areas of Alaska and gain access to the available data for the state or a project area. Interpretation of that data and evaluation of its suitability for use with any particular project is left to the user. Compilations, with sample data, have been published for much of the state; and are as follows: Wilson, and others (1979), southeastern Alaska; Wilson (1981), Aleutian Islands and Alaska Peninsula, Shew and Wilson (1981), southwestern Alaska; Wilson and others (1985), Yukon Crystalline terrane; Grybeck and others (1977), northern Alaska; Dadisman (1980), south-central Alaska.

20th-century glacial-marine sedimentation in Vitus Lake, Bering Glacier, Alaska, U.S.A.

USGS Publications Warehouse

Molnia, B.F.; Post, A.; Carlson, P.R.

1996-01-01

Vitus Lake, the ice-marginal basin at the southeastern edge of Bering Glacier, Alaska, U.S.A., is a site of modern, rapid, glacial-marine sedimentation. Rather than being a fresh-water lake, Vitus Lake is a tidally influenced, marine to brackish embayment connected to the Pacific Ocean by an inlet, the Seal River. Vitus Lake consists of five deep bedrock basins, separated by interbasinal highs. Glacial erosion has cut these basins as much as 250 m below sea level. High-resolution seismic reflection surveys conducted in 1991 and 1993 of four of Vitus Lake's basins reveal a complex, variable three-component acoustic stratigraphy. Although not fully sampled, the stratigraphy is inferred to be primarily glacial-marine units of (1) basal contorted and deformed glacial-marine and glacial sediments deposited by basal ice-contact processes and submarine mass-wasting; (2) acoustically well-stratified glacial-marine sediment, which unconformably overlies the basal unit and which grades upward into (3) acoustically transparent or nearly transparent glacial-marine sediment. Maximum thicknesses of conformable glacial-marine sediment exceed 100 m. All of the acoustically transparent and stratified deposits in Vitus Lake are modern in age, having accumulated between 1967 and 1993. The basins where these three-part sequences of "present-day" glacial-marine sediment are accumulating are themselves cut into older sequences of stratified glacial and glacial-marine deposits. These older units outcrop on the islands in Vitus Lake. In 1967, as the result of a major surge, glacier ice completely filled all five basins. Subsequent terminus retreat, which continued through August 1993, exposed these basins, providing new locations for glacial-marine sediment accumulation. A correlation of sediment thicknesses measured from seismic profiles at specific locations within the basins, with the year that each location became ice-free, shows that the sediment accumulation at some locations exceeds 10 m year-1.

Mineral deposits and metallogeny of Alaska

USGS Publications Warehouse

Goldfarb, Richard J.; Meighan, Corey J.; Meinert, Lawrence D.; Wilson, Frederic H.

2016-01-01

Alaska, the largest State within the United States, and mainly located north of latitude 60°, is an important part of the Circum-Arctic region. Alaska is a richly endowed region with a long and complex geologic history. The mining history is short by world standards but nevertheless there are a number of world-class deposits in Alaska, of which Red Dog and Pebble are among the largest of their respective types in the world. Alaska is a collection of geologic terranes or regions having distinct histories, most of which were tectonically assembled in the period from 400 million years to 50 million years ago (late Paleozoic through early Tertiary). They now occur as numerous fault-bounded blocks in the northernmost part of the North American Cordillera on the western margin of the Laurentian craton. These terranes are comprised of rocks ranging in age from Paleoproterozoic to Recent.

Individual and colony-specific wintering areas of Pacific northern fulmars (Fulmarus glacialis)

USGS Publications Warehouse

Hatch, Shyla A.; Gill, V.A.; Mulcahy, D.M.

2010-01-01

Seabird mortality associated with longline fishing in the eastern Bering Sea occurs mainly from September to May, with northern fulmars (Fulmarus glacialis) comprising the majority (60%) of the bycatch. Along the west coast of North America, winter dieoffs of fulmars may be increasing in frequency and magnitude, the most severe on record being a wreck that peaked in October-November 2003. We deployed satellite transmitters on fulmars from the four main Alaska colonies and tracked individuals for up to 2 years. Fulmars from Hall Island (northern Bering Sea) moved to Russian coastal waters after breeding, while Pribilof Island fulmars (southeastern Bering Sea) remained relatively sedentary yearround. Birds from Chagulak Island (eastern Aleutians) preferred passes between the Aleutian Islands in winter or foraged widely over deep waters of the central Bering Sea and North Pacific. Fulmars from the Semidi Islands (western Gulf of Alaska) migrated directly to waters of the California Current. Individuals from St. George Island (Pribilofs) and Chagulak were consistent in the places that they visited in two successive winters. The Pribilof Islands population is most affected by winter longlining for groundfish, whereas the Semidi Islands colony sustains most of the natural mortality that occurs off Washington, Oregon, and California.

Teleseismic P and S wave attenuation constraints on temperature and melt of the upper mantle in the Alaska Subduction Zone.

NASA Astrophysics Data System (ADS)

Soto Castaneda, R. A.; Abers, G. A.; Eilon, Z.; Christensen, D. H.

2017-12-01

Recent broadband deployments in Alaska provide an excellent opportunity to advance our understanding of the Alaska-Aleutians subduction system, with implications for subduction processes worldwide. Seismic attenuation, measured from teleseismic body waves, provides a strong constraint on thermal structure as well as an indirect indication of ground shaking expected from large intermediate-depth earthquakes. We measure P and S wave attenuation from pairwise amplitude and phase spectral ratios for teleseisms recorded at 204 Transportable Array, Alaska Regional, and Alaska Volcano Observatory, SALMON (Southern Alaska Lithosphere & Mantle Observation Network) and WVLF (Wrangell Volcanics & subducting Lithosphere Fate) stations in central Alaska. The spectral ratios are inverted in a least squares sense for differential t* (path-averaged attenuation operator) and travel time anomalies at every station. Our preliminary results indicate a zone of low attenuation across the forearc and strong attenuation beneath arc and backarc in the Cook Inlet-Kenai region where the Aleutian-Yakutat slab subducts, similar to other subduction zones. This attenuation differential is observed in both the volcanic Cook Inlet segment and amagmatic Denali segments of the Aleutian subduction zone. By comparison, preliminary results for the Wrangell-St. Elias region past the eastern edge of the Aleutian slab show strong attenuation beneath the Wrangell Volcanic Field, as well as much further south than in the Cook Inlet-Kenai region. This pattern of attenuation seems to indicate a short slab fragment in the east of the subduction zone, though the picture is complex. Results also suggest the slab may focus or transmit energy with minimal attenuation, adding to the complexity. To image the critical transition between the Alaska-Aleutian slab and the region to its east, we plan to incorporate new broadband data from the WVLF array, an ongoing deployment of 37 PASSCAL instruments installed in 2016. These stations have 10-20 km spacing, spanning the edge of the subducting slab, and so will provide a zone of increased resolution in the region where slab behavior is poorly understood. We will discuss these data in the context of enigmatic Wrangell volcanism and its relationship to the eastern end of the Alaska-Aleutian Wadati-Benioff zone.

Geology of the Prince William Sound and Kenai Peninsula region, Alaska

USGS Publications Warehouse

Wilson, Frederic H.; Hults, Chad P.

2012-01-01

The Prince William Sound and Kenai Peninsula region includes a significant part of one of the world’s largest accretionary complexes and a small part of the classic magmatic arc geology of the Alaska Peninsula. Physiographically, the map area ranges from the high glaciated mountains of the Alaska and Aleutian Ranges and the Chugach Mountains to the coastal lowlands of Cook Inlet and the Copper River delta. Structurally, the map area is cut by a number of major faults and postulated faults, the most important of which are the Border Ranges, Contact, and Bruin Bay Fault systems. The rocks of the map area belong to the Southern Margin composite terrane, a Tertiary and Cretaceous or older subduction-related accretionary complex, and the Alaska Peninsula terrane. Mesozoic rocks between these two terranes have been variously assigned to the Peninsular or the Hidden terranes. The oldest rocks in the map area are blocks of Paleozoic age within the mélange of the McHugh Complex; however, the protolith age of the greenschist and blueschist within the Border Ranges Fault zone is not known. Extensive glacial deposits mantle the Kenai Peninsula and the lowlands on the west side of Cook Inlet and are locally found elsewhere in the map area. This map was compiled from existing mapping, without generalization, and new or revised data was added where available.

Subaqueous tectonic geomorphology along a 400 km stretch of the Queen Charlotte-Fairweather Fault System, southeastern Alaska

NASA Astrophysics Data System (ADS)

Brothers, D. S.; Ten Brink, U. S.; Andrews, B. D.; Kluesner, J.; Haeussler, P. J.; Watt, J. T.; Dartnell, P.; Miller, N. C.; Conrad, J. E.; East, A. E.; Maier, K. L.; Balster-Gee, A.; Ebuna, D. R.

2016-12-01

Seismic and geodetic monitoring of active fault systems does not typically extend beyond one seismic cycle, hence it is challenging to link the characteristics of individual earthquakes with long-term fault behavior. A compelling place to examine such linkages is the right-lateral Queen Charlotte-Fairweather Fault (QCFF), a 1200 km dextral strike-slip fault offshore southeastern Alaska and western British Columbia. The QCFF defines the North America-Pacific transform plate boundary and has experienced at least eight M>7 earthquakes in the last 130 years. During 2015-2016, the USGS conducted four high-resolution marine geophysical surveys (multibeam bathymetry, sparker multichannel seismic and Chirp) along a 400-km-long section of the QCFF from Icy Point to Noyes Canyon. The QCFF displays a nearly linear and continuous fault trace from Icy Point to the southern tip of Baranof Island, a distance of 315 km. Subtle changes in fault strike, particularly the 200 km section fault south of Sitka Sound, are associated with pull-apart basins and compressional pop-up structures. Bathymetric imagery provides stunning views of strike-slip fault morphology along the continental shelf-edge and slope, including linear fault valleys and knife-edge lateral offset of submarine canyons, gullies, and ridges. We also observe pervasive evidence for small-scale (<1 km^2) submarine landslides along the margin and propose that they were seismically triggered. The glacially scoured southern wall of the Yakobi Sea Valley, formed 17 ka, is offset 925±25 m by the QCFF, providing a late Pleistocene-present slip-rate estimate of approximately 54 mm/yr. This suggests nearly the entire plate boundary motion is localized to a single, relatively narrow fault zone. We also constructed and analyzed a catalog of lateral piercing points along the fault to better understand long-term fault behavior, particularly along segments that have generated large historical earthquakes.

Components of Adolescent Depression in a Cross-Cultural Setting.

ERIC Educational Resources Information Center

Fischer, Margaret

Alaska has the highest rate in the nation of depression, alcohol and drug abuse, and adolescent suicide. The prevention of depression and suicide is complex because of many impinging variables. Data from a sample of 40 adolescents referred to a residential treatment center in Alaska revealed that a rapid change in life style of the Alaskan natives…

American Indian Tribal Values: A Critical Consideration in the Education of American Indians/Alaska Natives Today

ERIC Educational Resources Information Center

Tippeconnic, John W., III; Tippeconnic Fox, Mary Jo

2012-01-01

The education of American Indians and Alaska Natives has increasingly become more complex given the differences in tribal languages and cultures, especially as changing demographics and issues of Indian identity are considered. There are over 200 languages and vast cultural differences between and within the 565 federally recognized tribes in…

The complex Chukchi Borderland region as part of the Arctic Alaska extended margin

NASA Astrophysics Data System (ADS)

Saltus, R.; Hutchinson, D. R.; Miller, E. L.

2017-12-01

The Chukchi Borderland region (CBR; includes the Chukchi Plateau and its surrounding component elevations) is a physiographically complex and somewhat enigmatic seafloor high adjacent to the broad Chukchi Shelf in the Alaska/Chukotka quadrant of the Amerasian Basin beneath the Arctic Ocean. The CBR includes several physiographic sub-components including the relatively high-standing Northwind Ridge and Northwind Plain as well as a lower-standing northern region (here called the North Chukchi Component Elevation or NCCE) that consists of several un-named knolls, ramps, and benches. The CBR shows numerous N-S physiographic features including ridges and escarpments related to extension. The CBR adjoins the Chukchi Shelf to the south, abuts the Canada Basin to the east, and is separated on the west and north from the Mendeleev and Alpha Ridges by the Chukchi Plain, the Mendeleev Plain, and the Nautilus Basin. Available geophysical data, comparative physiography/geomorphology, and geologic analysis show that the CBR is continuous with Arctic Alaska and the adjoining Chukchi Shelf. CBR, Arctic Alaska, and the Chukchi Shelf share common early Paleozoic basement elements as well as Ellesmerian and younger cover sequences. The CBR owes its complex physiographic and structural character to its central location relative to the multiple extensional domains associated with the multi-stage rift formation of the Amerasian Basin, large igneous province-influenced volcanism associated with the Alpha and Mendeleev regions on the north and west, and hyper-extension of continental crust to the east in the deep Canada Basin. The CBR is often portrayed as an independent tectonic element within Arctic tectonic reconstructions, but we argue that models for the formation of the Amerasian Basin should include the CBR as an integral component of the Arctic Alaska microplate.

Geologic map of the Seldovia quadrangle, south-central Alaska

USGS Publications Warehouse

Bradley, Dwight C.; Kusky, Timothy M.; Haeussler, Peter J.; Karl, Susan M.; Donley, D. Thomas

1999-01-01

This is a 1:250,000-scale map of the bedrock geology of the Seldovia quadrangle, south-central Alaska. The map area covers the southwestern end of the Kenai Peninsula, including the Kenai Lowlands and Kenai Mountains, on either side of Kachemak Bay. The waters of Cook Inlet cover roughly half of the map area, and a part of the Alaska Peninsula near Iliamna Volcano lies in the extreme northwest corner of the map. The bedrock geology is based on new reconnaissance field work by the U.S. Geological Survey during parts of the 1988-1993 field seasons, and on previous mapping from a number of sources. The new mapping focused on the previously little-known Chugach accretionary complex in the Kenai Mountains. Important new findings include the recognition of mappable subdivisions of the McHugh Complex (a subduction melange of mostly Mesozoic protoliths), more accurate placement of the thrust contact between the McHugh Complex and Valdez Group (Upper Cretaceous trench turbidites), and the recognition of several new near-trench plutons of early Tertiary age.

Landscape change in the southern Piedmont: challenges, solutions, and uncertainty across scales

USGS Publications Warehouse

Conroy, M.J.; Allen, Craig R.; Peterson, J.T.; Pritchard, L.J.; Moore, C.T.

2003-01-01

The southern Piedmont of the southeastern United States epitomizes the complex and seemingly intractable problems and hard decisions that result from uncontrolled urban and suburban sprawl. Here we consider three recurrent themes in complicated problems involving complex systems: (1) scale dependencies and cross-scale, often nonlinear relationships; (2) resilience, in particular the potential for complex systems to move to alternate stable states with decreased ecological and/or economic value; and (3) uncertainty in the ability to understand and predict outcomes, perhaps particularly those that occur as a result of human impacts. We consider these issues in the context of landscape-level decision making, using as an example water resources and lotic systems in the Piedmont region of the southeastern United States.

Publications - RI 97-14A | Alaska Division of Geological & Geophysical

Science.gov Websites

Complex; Mystic Terrane; Ordovician; Ores; Paleocurrent; Paleoenvironment; Paleontology; Paleozoic; Peat ; Tertiary; Triassic; Turbidites; Veleska Lake Volcanic Complex; Volcanic; Yukon-Tanana Terrane Top of Page

Recent U.S. Geological Survey Studies in the Tintina Gold Province, Alaska, United States, and Yukon, Canada-Results of a 5-Year Project

USGS Publications Warehouse

Gough, Larry P.; Day, Warren C.

2010-01-01

This report presents summary papers of work conducted between 2002 and 2007 under a 5-year project effort funded by the U.S. Geological Survey Mineral Resources Program, formerly entitled 'Tintina Metallogenic Province: Integrated Studies on Geologic Framework, Mineral Resources, and Environmental Signatures.' As the project progressed, the informal title changed from 'Tintina Metallogenic Province' project to 'Tintina Gold Province' project, the latter being more closely aligned with the terminology used by the mineral industry. As Goldfarb and others explain in the first chapter of this report, the Tintina Gold Province is a convenient term used by the mineral exploration community for a 'region of very varied geology, gold deposit types, and resource potential'. The Tintina Gold Province encompasses roughly 150,000 square kilometers, bounded by the Kaltag-Tintina fault system on the north and the Farewell-Denali fault system on the south. It extends westward in a broad arc, some 200 km wide, from northernmost British Columbia, through the Yukon, through southeastern and central Alaska, to southwestern Alaska. The climate is subarctic and, in Alaska, includes major physiographic delineations and ecoregions such as the Yukon-Tanana Upland, Tanana-Kuskokwim Lowlands, Yukon River Lowlands, and the Kuskokwim Mountains. Although the Tintina Gold Province is historically important for some of the very first placer and lode gold discoveries in northern North America, it has recently seen resurgence in mineral exploration, development, and mining activity. This resurgence is due to both new discoveries (for example, Pogo and Donlin Creek) and to the application of modern extraction methods to previously known, but economically restrictive, low-grade, bulk-tonnage gold resources (for example, Fort Knox, Clear Creek, and Scheelite Dome). In addition, the Tintina Gold Province hosts numerous other mineral deposit types, possessing both high and low sulfide content, which are not currently in development.

KSC01kodi066

NASA Image and Video Library

2001-08-09

KODIAK ISLAND, Alaska -- The PICSat and Starshine 3 (back) payloads wait for their launch aboard the Athena 1 launch vehicle at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5 p.m. to 7 p.m. p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01KODI040

NASA Image and Video Library

2001-05-31

KODIAK ISLAND, Alaska -- Castor 120, the first stage of the Athena 1 launch vehicle, is raised off a truck at the launch pad at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01kodi063

NASA Image and Video Library

2001-08-09

KODIAK ISLAND, Alaska -- The PCSat payload waits for its launch aboard the Athena 1 launch vehicle at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5 p.m. to 7 p.m. p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01kodi072

NASA Image and Video Library

2001-08-08

KODIAK ISLAND, Alaska -- The Sapphire payload is moved into position next to the Starshine 3 payload at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5 p.m. to 7 p.m. p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01kodi059

NASA Image and Video Library

2001-07-31

KODIAK ISLAND, Alaska -- Technicians prepare the Starshine 3 payload for its launch aboard the Athena 1 launch vehicle at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01kodi064

NASA Image and Video Library

2001-08-09

KODIAK ISLAND, Alaska -- Technicians prepare the PICSat payload for its launch aboard the Athena 1 launch vehicle at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5 p.m. to 7 p.m. p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01KODI046

NASA Image and Video Library

2001-05-31

KODIAK ISLAND, Alaska -- Technicians install Orbis 21D Equipment Section Boost Motor, the second stage of the Athena 1 launch vehicle, at Kodiak Island, Alaska, as processing for the launch of Kodiak Star proceeds. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01kodi062

NASA Image and Video Library

2001-07-31

KODIAK ISLAND, Alaska -- Technicians prepare the Starshine 3 payload, while the payload fairing of the Athena 1 launch vehicle awaits servicing at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program

KSC01KODI043

NASA Image and Video Library

2001-05-31

KODIAK ISLAND, Alaska -- Castor 120, the first stage of the Athena 1 launch vehicle, is lowered into place at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01KODI039

NASA Image and Video Library

2001-05-31

KODIAK ISLAND, Alaska -- Trucks transporting Orbis 21D Equipment Section Boost Motor, the second stage of the Athena 1 launch vehicle, arrive at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01KODI055

NASA Image and Video Library

2001-05-29

KODIAK ISLAND, Alaska -- A convoy of trucks transports the stages of an Athena launch vehicle and supporting launch equipment to the pad at Kodiak Island, Alaska, as preparations to launch the Kodiak Star continue. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01kodi053

NASA Image and Video Library

2001-07-19

KODIAK ISLAND, Alaska -- A technician performs final testing on Starshine 3 at the Naval Research Laboratory in Washington, D.C., to prepare for the launch of the Kodiak Star at Kodiak Island, Alaska. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01KODI042

NASA Image and Video Library

2001-05-31

KODIAK ISLAND, Alaska -- Castor 120, the first stage of the Athena 1 launch vehicle, is lifted into a vertical position at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01kodi054

NASA Image and Video Library

2001-07-19

KODIAK ISLAND, Alaska -- A technician performs final testing on Starshine 3 at the Naval Research Laboratory in Washington, D.C., to prepare for the launch of the Kodiak Star at Kodiak Island, Alaska. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01KODI041

NASA Image and Video Library

2001-05-31

KODIAK ISLAND, Alaska -- Technicians inspect Castor 120, the first stage of the Athena 1 launch vehicle, at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

Contaminants and sea ducks in Alaska and the circumpolar region

USGS Publications Warehouse

Henny, Charles J.; Rudis, Deborah D.; Roffe, Thomas J.; Robinson-Wilson, Everett

1995-01-01

We review nesting sea duck population declines in Alaska during recent decades and explore the possibility that contaminants may be implicated. Aerial surveys of the surf scoter (Melanitta perspicillata), white-winged scoter (M. fusca), black scoter (M. nigra), oldsquaw (Clangula hyemalis), spectacled eider (Somateria fischeri), and Steller's eider (Polysticta stelleri) show long-term breeding population declines, especially the latter three species. The spectacled eider was recently classified threatened under the Endangered Species Act. In addition, three other diving ducks, which commonly winter in coastal areas, have declined from unknown causes. Large die-offs of all three species of scoters during molt, a period of high energy demand, were documented in August 1990, 1991, and 1992 at coastal reefs in southeastern Alaska. There was no evidence of infectious diseases in those scoters. The die-offs may or may not be associated with the long-term declines. Many scoters had elevated renal concentrations of cadmium (high of 375 μg/g dry weight [dw]). Effects of cadmium in sea ducks are not well understood. Selenium concentrations in livers of nesting white-winged scoters were high; however, the eggs they laid contained less selenium than expected based on relationships for freshwater bird species. Histological evaluation found a high prevalence of hepatocellular vacuolation (49%), a degenerative change frequently associated with sublethal toxic insult. Cadmium and selenium mean liver concentrations were generally higher in those birds with more severe vacuolation; however, relationships were not statistically significant. We do not know if sea duck population declines are related to metals or other contaminants.

Contaminants and sea ducks in Alaska and the circumpolar region

USGS Publications Warehouse

Henny, C.J.; Rudis, D.D.; Roffe, T.J.; Robinson-Wilson, E.

1995-01-01

We review nesting sea duck population declines in Alaska during recent decades and explore the possibility that contaminants may be implicated. Aerial surveys of the surf scoter (Melanitta perspicillata) , white-winged scoter (M. fusca) , black scoter (M. nigra) , oldsquaw (Clangula hyemalis) , spectacled eider (Somateria fischeri) , and Steller's eider (Polysticta stelleri) show long-term breeding population declines, especially the latter three species. The spectacled eider was recently classified threatened under the Endangered Species Act. In addition, three other diving ducks, which commonly winter in coastal areas, have declined from unknown causes. Large die-offs of all three species of scoters during molt, a period of high energy demand, were documented in August 1990, 1991, and 1992 at coastal reefs in southeastern Alaska. There was no evidence of infectious diseases in those scoters. The die-offs may or may not be associated with the long-term declines. Many scoters had elevated renal concentrations of cadmium (high of 375 ?g/g dry weight [dw]). Effects of cadmium in sea ducks are not well understood. Selenium concentrations in livers of nesting white-winged scoters were high ; however, the eggs they laid contained less selenium than expected based on relationships for freshwater bird species. Histological evaluation found a high prevalence of hepatocellular vacuolation (49%) , a degenerative change frequently associated with sublethal toxic insult. Cadmium and selenium mean liver concentrations were generally higher in those birds with more severe vacuolation ; however, relationships were not statistically significant. We do not know if sea duck population declines are related to metals or other contaminants.

2006 Compilation of Alaska Gravity Data and Historical Reports

USGS Publications Warehouse

Saltus, Richard W.; Brown, Philip J.; Morin, Robert L.; Hill, Patricia L.

2008-01-01

Gravity anomalies provide fundamental geophysical information about Earth structure and dynamics. To increase geologic and geodynamic understanding of Alaska, the U.S. Geological Survey (USGS) has collected and processed Alaska gravity data for the past 50 years. This report introduces and describes an integrated, State-wide gravity database and provides accompanying gravity calculation tools to assist in its application. Additional information includes gravity base station descriptions and digital scans of historical USGS reports. The gravity calculation tools enable the user to reduce new gravity data in a consistent manner for combination with the existing database. This database has sufficient resolution to define the regional gravity anomalies of Alaska. Interpretation of regional gravity anomalies in parts of the State are hampered by the lack of local isostatic compensation in both southern and northern Alaska. However, when filtered appropriately, the Alaska gravity data show regional features having geologic significance. These features include gravity lows caused by low-density rocks of Cenozoic basins, flysch belts, and felsic intrusions, as well as many gravity highs associated with high-density mafic and ultramafic complexes.

A Comparative, Holistic, Multiple-Case Study of the Implementation of the Strategic Thinking Protocol© and Traditional Strategic Planning Processes at a Southeastern University

ERIC Educational Resources Information Center

Robinson, Deborah J.

2012-01-01

This study explores the strategic thinking and strategic planning efforts in a department, college and university in the Southeastern United States. The goal of the study was to identify elements of strategic planning processes that meet the unique organizational features and complexities of a higher education institution. The study employed a…

Complex forest dynamics indicate potential for slowing carbon accumulation in the southeastern United States

Treesearch

John W. Coulston; David N. Wear; James M. Vose

2015-01-01

Over the past century forest regrowth in Europe and North America expanded forest carbon (C) sinks and offset C emissions but future C accumulation is uncertain. Policy makers need insights into forest C dynamics as they anticipate emissions futures and goals. We used land use and forest inventory data to estimate how forest C dynamics have changed in the southeastern...

Thermal evolution of sedimentary basins in Alaska

USGS Publications Warehouse

Johnsson, Mark J.; Howell, D.G.

1996-01-01

The complex tectonic collage of Alaska is reflected in the conjunction of rocks of widely varying thermal maturity. Indicators of the level of thermal maturity of rocks exposed at the surface, such as vitrinite reflectance and conodont color alteration index, can help constrain the tectonic evolution of such complex regions and, when combined with petrographic, modern heat flow, thermogeochronologic, and isotopic data, allow for the detailed evaluation of a region?s burial and uplift history. We have collected and assembled nearly 10,000 vitrinite-reflectance and conodont-color-alteration index values from the literature, previous U.S. Geological Survey investigations, and our own studies in Alaska. This database allows for the first synthesis of thermal maturity on a broadly regional scale. Post-accretionary sedimentary basins in Alaska show wide variability in terms of thermal maturity. The Tertiary interior basins, as well as some of the forearc and backarc basins associated with the Aleutian Arc, are presently at their greatest depth of burial, with immature rocks exposed at the surface. Other basins, such as some backarc basins on the Alaska Peninsula, show higher thermal maturities, indicating modest uplift, perhaps in conjunction with higher geothermal gradients related to the arc itself. Cretaceous ?flysch? basins, such as the Yukon-Koyukuk basin, are at much higher thermal maturity, reflecting great amounts of uplift perhaps associated with compressional regimes generated through terrane accretion. Many sedimentary basins in Alaska, such as the Yukon-Koyukuk and Colville basins, show higher thermal maturity at basin margins, perhaps reflecting greater uplift of the margins in response to isostatic unloading, owing to erosion of the hinterland adjacent to the basin or to compressional stresses adjacent to basin margins.

Using hyperspectral imagery to estimate forest floor consumption from wildfire in boreal forests of Alaska, USA

Treesearch

Sarah A. Lewis; Andrew T. Hudak; Roger D. Ottmar; Peter R. Robichaud; Leigh B. Lentile; Sharon M. Hood; James B. Cronan; Penny Morgan

2011-01-01

Wildfire is a major forest disturbance in interior Alaska that can both directly and indirectly alter ecological processes. We used a combination of pre- and post-fire forest floor depths and post-fire ground cover assessments measured in the field, and high-resolution airborne hyperspectral imagery, to map forest floor conditions after the 2004 Taylor Complex in...

Alaska, Naturally Occurring Asbestos: Experiences, Policy and 2012 Limitation of Liability Legislation

NASA Astrophysics Data System (ADS)

Hargesheimer, J.; Perkins, R.

2012-12-01

Naturally Occurring Asbestos (NOA) occurs in mineral deposits in Alaska. There are many regions in Alaska that have minerals in surface rocks that may contain asbestos and asbestos has been discovered in many locations in Alaska. Gravel is constantly in demand for heavy construction projects, but some remote localities in Alaska do not have gravel sources that are NOA-free. Determining if NOA can be safely used in heavy construction materials and what can or should be done with NOA materials that are already in place are complex questions. Answers will depend on the amount and type of asbestos mineral, how it is handled in processing, and how it is maintained - all subject to regulation and control of operations. The State of Alaska recently enacted legislation (HB 258) providing, among other things, "… immunity for the state and for landowners, extractors, suppliers, transporters, and contractors for certain actions or claims arising in connection with the use of gravel or aggregate material containing naturally occurring asbestos in certain areas." Implementation of the law and interim regulations and guidance should enable use of NOA for heavy construction materials in Alaska, but as with any new law, it will take some time to understand its full scope and effect.

KSC01KODI035

NASA Image and Video Library

2001-05-29

KODIAK ISLAND, Alaska -- A special platform connects the barge with a ramp to allow Castor 120, the first stage of the Athena 1 launch vehicle, to safely move onto the dock at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01kodi058

NASA Image and Video Library

2001-07-31

KODIAK ISLAND, Alaska -- Technicians prepare the Starshine 3 payload for its launch aboard the Athena 1 launch vehicle, while the payload fairing awaits processing, at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01KODI045

NASA Image and Video Library

2001-05-31

KODIAK ISLAND, Alaska -- Technicians inspect and secure Castor 120, the first stage of the Athena 1 launch vehicle, on the launch mount at Kodiak Island, Alaska, as processing for the launch of Kodiak Star proceeds. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01KODI036

NASA Image and Video Library

2001-05-29

KODIAK ISLAND, Alaska -- A boat moves a ramp into place that will allow Castor 120, the first stage of the Athena 1 launch vehicle, to safely move onto the dock at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

Field guide to the Mesozoic arc and accretionary complex of South-Central Alaska, Indian to Hatcher Pass

USGS Publications Warehouse

Karl, Susan M.; Oswald, P.J.; Hults, Chad P.

2015-01-01

This field trip traverses exposures of a multi-generation Mesozoic magmatic arc and subduction-accretion complex that had a complicated history of magmatic activity and experienced variations in composition and deformational style in response to changes in the tectonic environment. This Mesozoic arc formed at an unknown latitude to the south, was accreted to North America, and was subsequently transported along faults to its present location (Plafker and others, 1989; Hillhouse and Coe, 1994). Some of these faults are still active. Similar tectonic, igneous, and sedimentary processes to those that formed the Mesozoic arc complex persist today in southern Alaska, building on, and deforming the Mesozoic arc. The rocks we will see on this field trip provide insights on the three-dimensional composition of the modern arc, and the processes involved in the evolution of an arc and its companion accretionary complex.

Developing silvicultural systems based on partial cutting in western hemlock–Sitka spruce stands of southeast Alaska.

Treesearch

Robert L. Deal; J.C. Tappeiner; Paul E. Hennon

2002-01-01

The effects of partial cutting on species composition, stand structure and growth, tree size distribution, and tree disease and mortality were evaluated on 73 plots in 18 stands that were harvested 12–96 years ago in southeast Alaska. Partially-cut stands had diverse and highly complex stand structures similar to uncut stands. Sitka spruce was maintained in mixed...

Survival of adult Steller sea lions in Alaska: senescence, annual variation and covariation with male reproductive success.

PubMed

Hastings, Kelly K; Jemison, Lauri A; Pendleton, Grey W

2018-01-01

Population dynamics of long-lived vertebrates depend critically on adult survival, yet factors affecting survival and covariation between survival and other vital rates in adults remain poorly examined for many taxonomic groups of long-lived mammals (e.g. actuarial senescence has been examined for only 9 of 34 extant pinniped species using longitudinal data). We used mark-recapture models and data from 2795 Steller sea lion ( Eumetopias jubatus ) pups individually marked at four of five rookeries in southeastern Alaska (SEAK) and resighted for 21 years to examine senescence, annual variability and covariation among life-history traits in this long-lived, sexually dimorphic pinniped. Sexes differed in age of onset (approx. 16-17 and approx. 8-9 years for females and males, respectively), but not rate (-0.047 and -0.046/year of age for females and males) of senescence. Survival of adult males from northern SEAK had greatest annual variability (approx. ±0.30 among years), whereas survival of adult females ranged approximately ±0.10 annually. Positive covariation between male survival and reproductive success was observed. Survival of territorial males was 0.20 higher than that of non-territorial males, resulting in the majority of males alive at oldest ages being territorial.

Survival of adult Steller sea lions in Alaska: senescence, annual variation and covariation with male reproductive success

PubMed Central

Jemison, Lauri A.; Pendleton, Grey W.

2018-01-01

Population dynamics of long-lived vertebrates depend critically on adult survival, yet factors affecting survival and covariation between survival and other vital rates in adults remain poorly examined for many taxonomic groups of long-lived mammals (e.g. actuarial senescence has been examined for only 9 of 34 extant pinniped species using longitudinal data). We used mark–recapture models and data from 2795 Steller sea lion (Eumetopias jubatus) pups individually marked at four of five rookeries in southeastern Alaska (SEAK) and resighted for 21 years to examine senescence, annual variability and covariation among life-history traits in this long-lived, sexually dimorphic pinniped. Sexes differed in age of onset (approx. 16–17 and approx. 8–9 years for females and males, respectively), but not rate (−0.047 and −0.046/year of age for females and males) of senescence. Survival of adult males from northern SEAK had greatest annual variability (approx. ±0.30 among years), whereas survival of adult females ranged approximately ±0.10 annually. Positive covariation between male survival and reproductive success was observed. Survival of territorial males was 0.20 higher than that of non-territorial males, resulting in the majority of males alive at oldest ages being territorial. PMID:29410794

Return of warm conditions in the southeastern Bering Sea: Physics to fluorescence

PubMed Central

Duffy-Anderson, J. T.; Eisner, L. B.; Farley, E. V.; Heintz, R. A.; Mordy, C. W.

2017-01-01

From 2007 to 2013, the southeastern Bering Sea was dominated by extensive sea ice and below-average ocean temperatures. In 2014 there was a shift to reduced sea ice on the southern shelf and above-average ocean temperatures. These conditions continued in 2015 and 2016. During these three years, the spring bloom at mooring site M4 (57.9°N, 168.9°W) occurred primarily in May, which is typical of years without sea ice. At mooring site M2 (56.9°N, 164.1°W) the spring bloom occurred earlier especially in 2016. Higher chlorophyll fluorescence was observed at M4 than at M2. In addition, these three warm years continued the pattern near St. Matthew Island of high concentrations (>1 μM) of nitrite occurring during summer in warm years. Historically, the dominant parameters controlling sea-ice extent are winds and air temperature, with the persistence of frigid, northerly winds in winter and spring resulting in extensive ice. After mid-March 2014 and 2016 there were no cold northerly or northeasterly winds. Cold northerly winds persisted into mid-April in 2015, but did not result in extensive sea ice south of 58°N. The apparent mechanism that helped limit ice on the southeastern shelf was the strong advection of warm water from the Gulf of Alaska through Unimak Pass. This pattern has been uncommon, occurring in only one other year (2003) in a 37-year record of estimated transport through Unimak Pass. During years with no sea ice on the southern shelf (e.g. 2001–2005, 2014–2016), the depth-averaged temperature there was correlated to the previous summers ocean temperature. PMID:28957386

Landscape change in the Southern Piedmont: Challenges, solutions and uncertainty across scales

USGS Publications Warehouse

Conroy, M.J.; Allen, Craig R.; Peterson, J.T.; Pritchard, L.; Moore, C.T.

2003-01-01

The southern Piedmont of the southeastern United States epitomizes the complex and seemingly intractable problems and hard decisions that result from uncontrolled urban and suburban sprawl. Here we consider three recurrent themes in complicated problems involving complex systems: (1) scale dependencies and cross-scale, often nonlinear relationships; (2) resilience, in particular the potential for complex systems to move to alternate stable states with decreased ecological and/or economic value; and (3) uncertainty in the ability to understand and predict outcomes, perhaps particularly those that occur as a result of human impacts. We consider these issues in the context of landscape-level decision making, using as an example water resources and lotic systems in the Piedmont region of the southeastern United States. Copyright ?? 2003 by the author(s). Published here under licence by The Resilience Alliance.

Reduction of earthquake risk in the united states: Bridging the gap between research and practice

USGS Publications Warehouse

Hays, W.W.

1998-01-01

Continuing efforts under the auspices of the National Earthquake Hazards Reduction Program are under way to improve earthquake risk assessment and risk management in earthquake-prone regions of Alaska, California, Nevada, Washington, Oregon, Arizona, Utah, Wyoming, and Idaho, the New Madrid and Wabash Valley seismic zones in the central United States, the southeastern and northeastern United States, Puerto Rico, Virgin Islands, Guam, and Hawaii. Geologists, geophysicists, seismologists, architects, engineers, urban planners, emergency managers, health care specialists, and policymakers are having to work at the margins of their disciplines to bridge the gap between research and practice and to provide a social, technical, administrative, political, legal, and economic basis for changing public policies and professional practices in communities where the earthquake risk is unacceptable. ?? 1998 IEEE.

KSC01KODI051

NASA Image and Video Library

2001-06-19

KODIAK ISLAND, Alaska -- Technicians lower the fueled Orbit Adjust Model (OAM), which navigates payloads into the correct orbit, onto Orbis 21D Equipment Section Boost Motor, the second stage of the Athena 1 launch vehicle, at the launch pad at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

KSC01KODI050

NASA Image and Video Library

2001-06-19

KODIAK ISLAND, Alaska -- The fueled Orbit Adjust Model (OAM), which navigates payloads into the correct orbit, is installed onto Orbis 21D Equipment Section Boost Motor, the second stage of the Athena 1 launch vehicle, at the launch pad at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

Interim report on the St. Elias, Alaska earthquake of 28 February 1979

USGS Publications Warehouse

Lahr, John C.; Plafker, George; Stephens, C.D.; Foglean, K.A.; Blackford, M.E.

1979-01-01

On 28 February 1979 an earthquake with surface wave magnitude (Ms) of 7.7 (W. Person, personal communication, 1979) occurred beneath the Chugach and St. Elias mountains of southern Alaska (fig. 1). This is a region of complex tectonics resulting from northwestward convergence between the Pacific and North American plates. To the east, the northwest-trending Fairweather fault accommodates the movement with dextral slip of about 5.5 cm/yr (Plafker, Hudson, and others, 1978); to the west, the Pacific plate underthrusts Alaska at the Aleutian trench, which trends southwestward (Plafker 1969). The USGS has operated a telemetered seismic network in southern Alaska since 1971 and it was greatly expanded along the eastern Gulf of Alaska in September 1974. The current configuration of stations is shown in Figure 9. Technical details of the network are available in published earthquake catalogs (Lahr, Page, and others, 1974; Fogleman, Stephens, and others, 1978). Preliminary analysis of the data from this network covering the time period September 1, 1978 through March 10, 1979, as well as worldwide data for the main shock will be discussed in this paper.

Comparative analysis of alternative co-production approaches to conservation science in Alaska

NASA Astrophysics Data System (ADS)

Trammell, E. J.

2017-12-01

Co-production has been suggested as an important tool for reducing the gap between science and management. Although co-production can require substantial investments in time and relationship building, there are a range of possible approaches that can be utilized that honor the focus and intent of co-production. I present here a comparison of three efforts that range from relatively simple, to complex and exhaustive, that illustrate diverse approaches to co-production of conservation science in Alaska. The first example highlights a workshop-based approach to identify long-term environmental monitoring needs in Alaska, while the second example describes stakeholder-driven scenarios that identified stressors to salmon in southcentral Alaska. The third example describes a 2-year cooperative agreement to develop management questions as part of a rapid ecoregional assessment in central Alaska. Results suggest that careful stakeholder selection is essential to successful co-production. Additionally, all three examples highlight the potential disconnect between management questions and specific management decisions, even when working directly with resource managers. As the focus of the Alaska Climate Science Center will be on co-production of climate science over the next 5 years, I conclude with some key pathways forward for successful co-production efforts in the future.

A new Neotibicen cicada subspecies (Hemiptera: Cicadidae) from the southeastern USA forms hybrid zones with a widespread relative despite a divergent male calling song.

PubMed

Marshall, David C; Hill, Kathy B R

2017-05-31

A morphologically cryptic subspecies of Neotibicen similaris (Smith and Grossbeck) is described from forests of the Apalachicola region of the southeastern United States. Although the new form exhibits a highly distinctive male calling song, it hybridizes extensively where it meets populations of the nominate subspecies in parapatry, by which it is nearly surrounded. This is the first reported example of hybridization between North American nonperiodical cicadas. Acoustic and morphological characters are added to the original description of the nominate subspecies, and illustrations of complex hybrid song phenotypes are presented. The biogeography of N. similaris is discussed in light of historical changes in forest composition on the southeastern Coastal Plain.

Paleozoic carbonate buildup (reef) inventory, central and southeastern Idaho

DOE Office of Scientific and Technical Information (OSTI.GOV)

Isaacson, P.E.

1987-08-01

Knowledge of central and southeastern Idaho's Paleozoic rocks to date suggest that three styles of buildup (reef) complexes occur in Late Devonian, Mississippian, and Pennsylvanian-Permian time. The Late Devonian Jefferson Formation has stromatoporoid and coral (both rugosan and tabulate) organisms effecting a buildup in the Grandview Canyon vicinity; Early Mississippian Waulsortian-type mud mounds occur in the Lodgepole formation of southeastern Idaho; there are Late Mississippian Waulsortian-type mounds in the Surrett Canyon Formation of the Lost River Range; and cyclic Pennsylvanian-Permian algal and hydrozoan buildups occur in the Juniper gulch Member of the Snaky Canyon Formation in the Arco Hills andmore » Lemhi Range. Late Devonian (Frasnian) carbonates of the Jefferson formation show buildup development on deep ramp sediments.« less

Late Glacial-Holocene Pollen-Based Vegetation History from Pass Lake, Prince of Wales Island, Southeastern Alaska

USGS Publications Warehouse

Ager, Thomas A.; Rosenbaum, Joseph G.

2009-01-01

A radiocarbon-dated history of vegetation development since late Wisconsin deglaciation has been reconstructed from pollen evidence preserved in a sediment core from Pass Lake on Prince of Wales Island, southeastern Alaska. The shallow lake is in the south-central part of the island and occupies a low pass that was filled by glacial ice of local origin during the late Wisconsin glaciation. The oldest pollen assemblages indicate that pine woodland (Pinus contorta) had developed in the area by ~13,715 cal yr B.P. An abrupt decline in the pine population, coinciding with expansion of alder (Alnus) and ferns (mostly Polypodiaceae) began ~12,875 yr B.P., and may have been a response to colder, drier climates during the Younger Dryas climatic interval. Mountain hemlock (Tsuga mertensiana) began to colonize central Prince of Wales Island by ~11,920 yr B.P. and was soon followed by Sitka spruce (Picea sitchensis). Pollen of western hemlock (Tsuga heterophylla) began to appear in Pass Lake sediments soon after 11,200 yr B.P. The abundance of western hemlock pollen in the Pass Lake core during most of the Holocene appears to be the result of wind transport from trees growing at lower altitudes on the island. The late Holocene pollen record from Pass Lake is incomplete because of one or more unconformities, but the available record suggests that a vegetation change occurred during the late Holocene. Increases in pollen percentages of pine, cedar (probably yellow cedar, Chamaecyparis nootkatensis), and heaths (Ericales) suggest an expansion of muskeg vegetation occurred in the area during the late Holocene. This vegetation change may be related to the onset of cooler, wetter climates that began as early as ~3,774 yr B.P. in the region. This vegetation history provides the first radiocarbon-dated Late Glacial-Holocene terrestrial paleoecological framework for Prince of Wales Island. An analysis of magnetic properties of core sediments from Pass Lake suggests that unconformities caused by low lake levels may be detectable where fine-grained ferrimagnets are concentrated in peaty sediments.

High-Resolution Geophysical Constraints on Late Pleistocene-Present Deformation History, Seabed Morphology, and Slip-Rate along the Queen Charlotte-Fairweather Fault, Offshore Southeastern Alaska

NASA Astrophysics Data System (ADS)

Brothers, D. S.; Haeussler, P. J.; Dartnell, P.; Conrad, J. E.; Kluesner, J. W.; Hart, P. E.; Witter, R. C.; Balster-Gee, A. F.; Maier, K. L.; Watt, J. T.; East, A. E.

2015-12-01

The Queen Charlotte-Fairweather Fault (QCFF) of southeastern Alaska and British Columbia is the dominant fault along the 1200 km-long transform boundary between the Pacific and North American plates. More than 900 km of the QCFF lies offshore where the style and rates of deformation are poorly constrained due to a lack of high-resolution marine geophysical data. In May 2015, the USGS acquired ~900 km2 of high-resolution multibeam bathymetry data and >2000 line-km of high-resolution multichannel seismic reflection profiles between Cross Sound, Yakobi Sea Valley, and Icy Point (the northernmost offshore section of the QCFF) using a 24-ch streamer and 500 Joule minisparker source. During a second cruise in August 2015 we conducted targeted multichannel seismic and subbottom CHIRP profiling in the same region. The new data reveal a single trace of the QCFF expressed as a clear and remarkably straight seafloor lineation for >60 km. Subtle jogs in the fault (<3 degrees) are associated with pop-up structures and en echelon pull-apart basins. The near surface deformation along the fault never exceeds a width of 1.2 km. Northward, as the fault approaches Icy Point and a restraining bend, it splays into multiple strands and displays evidence for uplift and transpression. The fault appears to transition from almost purely strike-slip in the south to oblique-convergence as it steps onshore to the north. The QCFF cuts through the Yakobi Sea Valley and Cross Sound, two elongate bathymetric troughs that were filled with glaciers as recently as 17-19 ka. The southern wall of the Yakobi Sea Valley is offset 890±30 m by the QCFF, providing a late Pleistocene-present slip-rate estimate of 45-54 mm/yr. This suggests that nearly the entire plate boundary slip budget is confined to a single, narrow, strike-slip fault zone, which may have implications for models of plate boundary strain localization.

Age, distribution and style of deformation in Alaska north of 60°N: Implications for assembly of Alaska

USGS Publications Warehouse

Moore, Thomas; Box, Stephen E.

2016-01-01

The structural architecture of Alaska is the product of a complex history of deformation along both the Cordilleran and Arctic margins of North America involving oceanic plates, subduction zones and strike-slip faults and with continental elements of Laurentia, Baltica, and Siberia. We use geological constraints to assign regions of deformation to 14 time intervals and to map their distributions in Alaska. Alaska can be divided into three domains with differing deformational histories. Each domain includes a crustal fragment that originated near Early Paleozoic Baltica. The Northern domain experienced the Early Cretaceous Brookian orogeny, an oceanic arc-continent collision, followed by mid-Cretaceous extension. Early Cretaceous opening of the oceanic Canada Basin rifted the orogen from the Canadian Arctic margin, producing the bent trends of the orogen. The second (Southern) domain consists of Neoproterozoic and younger crust of the amalgamated Peninsular-Wrangellia-Alexander arc terrane and its paired Mesozoic accretionary prism facing the Pacific Ocean basin. The third (Interior) domain, situated between the first two domains and roughly bounded by the Cenozoic dextral Denali and Tintina faults, includes the large continental Yukon Composite and Farewell terranes having different Permian deformational episodes. Although a shared deformation that might mark their juxtaposition by collisional processes is unrecognized, sedimentary linkage between the two terranes and depositional overlap of the boundary with the Northern domain occurred by early Late Cretaceous. Late Late Cretaceous deformation is the first deformation shared by all three domains and correlates temporally with emplacement of the Southern domain against the remainder of Alaska. Early Cenozoic shortening is mild across interior Alaska but is significant in the Brooks Range, and correlates in time with dextral faulting, ridge subduction and counter-clockwise rotation of southern Alaska. Late Cenozoic shortening is significant in southern Alaska inboard of the underthrusting Yakutat terrane at the Pacific margin and in northeastern Alaska.

EDGE (Experiential Discoveries in Geoscience Education) Field Course Provides Alaskan High School and Middle School students with Earth Science and GIS Skills for Science Fair Projects and a College Experience

NASA Astrophysics Data System (ADS)

Connor, C. L.; Prakash, A.; Brownlee, M.; Nagorski, S.; Walling, R.

2006-12-01

For this outreach project we created watershed scale field activities in the Mendenhall Glacier system in Juneau, Alaska to introduce pre-college students to earth surface processes. These activities were designed to teach field data collection methods and to provide experiences that included exposure to the disciplines of glaciology, hydrology, and geomorphology. Students used their own observations to understand the on-going effects of warming climate in southeastern Alaska. Twenty seven, pre-college students from throughout the state participated in a 5-day, two-credit, introductory college-level course. This course was designed to introduce them to earth science as practiced in the field. Students divided their time between field sessions with data collection and indoor GIS labs. EDGE field excursions enabled students to learn about glacial geomorphology from river rafts, to collect stream discharge and other hydrologic data in local streams, and to integrate glacier recession observations with GPS waypoints collected from observed recessional positions. In labs at the University of Alaska Southeast campus, EDGE students were introduced to the fundamentals of ArcGIS. They downloaded their GPS waypoints onto modern and historic maps. They analyzed their stream flow data and created dynamic maps using their own observations in the field. During Fall 2006 semester, the students will generate earth science projects in their villages and towns that they can complete and present to their peers. EDGE teachers who attended a 10 day workshop in June will mentor their EDGE students. EDGE teachers and students will return to the UAS Juneau campus in March 2007 for a symposium. EGDE students will present their projects to Juneau area undergraduates and Juneau School District K-12 classes. In addition EDGE high school students will have the option to enter and compete in the Southeast Alaska Regional Science Fair held the same weekend. Funding from the National Science Foundation (NSF), US Department of Education, and NASA Space Grant programs will support 3-4 cohorts of EDGE teachers and 2-3 cohorts of EDGE students.

High abundance of salps in the coastal Gulf of Alaska during 2011: A first record of bloom occurrence for the northern Gulf

NASA Astrophysics Data System (ADS)

Li, Kaizhi; Doubleday, Ayla J.; Galbraith, Moira D.; Hopcroft, Russell R.

2016-10-01

Atypical high abundances of two salp species occurred in the coastal Gulf of Alaska during 2011. Salpa aspera dominated numerically in aggregate form during spring, and became uncommon during summer, while Cyclosalpa bakeri increased from low during spring to high abundance during summer. Both species were absent, or nearly so, by fall. C. bakeri abundance was positively correlated to surface temperature in spring and summer, and both species abundances were negatively correlated to chlorophyll a. The proportion of aggregate forms of both species was higher than that of solitary forms during spring and summer. The length-frequency of S. aspera aggregate individuals ranged primarily from 10 to 50 mm, and solitary forms reached 130 mm, while C. bakeri aggregates were 10-25 mm, with solitary forms up to 75 mm. Estimated biomass of S. aspera was 0.35±0.64 mg C m-3 in southeastern Alaska during spring then decreased to 0.03±0.12 mg C m-3 during summer. Estimated biomass of C. bakeri was 0.03±0.06 mg C m-3 over the entire sampling domain during spring, then rose to 0.15±0.25 mg C m-3 during summer. The volume of water filtered daily by S. aspera was estimated to be up to 17% of the 200 m water column at some stations during spring, but only up to 3.5% during summer. Substantially higher grazing impact was possible if animals were largely confined to the surface mixed layer (typically 20-30 m thick). The average volume filtrated was higher during spring for S. aspera, but for C. bakeri it was higher during summer. We propose that the combined effect of the northward transport of seed populations, their rapid biomass increase through asexual reproduction, and the high clearance rate of salps contributed to atypically low chlorophyll a in the Gulf of Alaska during spring and summer of 2011. This unusual event impacted ecosystem function during 2011, and might be expected to increase in frequency as the Gulf continues to respond to climate variations.

Geomorphic domains and linear features on Landsat images, Circle Quadrangle, Alaska

USGS Publications Warehouse

Simpson, S.L.

1984-01-01

A remote sensing study using Landsat images was undertaken as part of the Alaska Mineral Resource Assessment Program (AMRAP). Geomorphic domains A and B, identified on enhanced Landsat images, divide Circle quadrangle south of Tintina fault zone into two regional areas having major differences in surface characteristics. Domain A is a roughly rectangular, northeast-trending area of relatively low relief and simple, widely spaced drainages, except where igneous rocks are exposed. In contrast, domain B, which bounds two sides of domain A, is more intricately dissected showing abrupt changes in slope and relatively high relief. The northwestern part of geomorphic domain A includes a previously mapped tectonostratigraphic terrane. The southeastern boundary of domain A occurs entirely within the adjoining tectonostratigraphic terrane. The sharp geomorphic contrast along the southeastern boundary of domain A and the existence of known faults along this boundary suggest that the southeastern part of domain A may be a subdivision of the adjoining terrane. Detailed field studies would be necessary to determine the characteristics of the subdivision. Domain B appears to be divisible into large areas of different geomorphic terrains by east-northeast-trending curvilinear lines drawn on Landsat images. Segments of two of these lines correlate with parts of boundaries of mapped tectonostratigraphic terranes. On Landsat images prominent north-trending lineaments together with the curvilinear lines form a large-scale regional pattern that is transected by mapped north-northeast-trending high-angle faults. The lineaments indicate possible lithlogic variations and/or structural boundaries. A statistical strike-frequency analysis of the linear features data for Circle quadrangle shows that northeast-trending linear features predominate throughout, and that most northwest-trending linear features are found south of Tintina fault zone. A major trend interval of N.64-72E. in the linear feature data, corresponds to the strike of foliations in metamorphic rocks and magnetic anomalies reflecting compositional variations suggesting that most linear features in the southern part of the quadrangle probably are related to lithologic variations brought about by folding and foliation of metamorphic rocks. A second important trend interval, N.14-35E., may be related to thrusting south of the Tintina fault zone, as high concentrations of linear features within this interval are found in areas of mapped thrusts. Low concentrations of linear features are found in areas of most igneous intrusives. High concentrations of linear features do not correspond to areas of mineralization in any consistent or significant way that would allow concentration patterns to be easily used as an aid in locating areas of mineralization. The results of this remote sensing study indicate that there are several possibly important areas where further detailed studies are warranted.

KSC01kodi049

NASA Image and Video Library

2001-06-19

KODIAK ISLAND, Alaska -- Orbis 21D Equipment Section Boost Motor, the second stage of the Athena 1 launch vehicle, awaits the installation of the Orbit Adjust Model (OAM), which navigates the payloads into the correct orbit, at the launch pad at Kodiak Island, Alaska, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

Coordination and Convening of the 2016 Arctic Science Summit Week

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hinzman, Larry D.

The Arctic Science Summit Week, Arctic Observing Summit, Arctic Council Senior Arctic Officials, Model Arctic Council, and International Arctic Assembly were convened on the campus of the University of Alaska Fairbanks with great productivity and satisfaction of the participants. We were pleased to welcome over 1000 participants from 30 different nations and over 130 different institutions. The organization and execution of these meetings was extensive and complex involving more than 250 coordinators, volunteers and contributors from across Alaska. The participants were enthusiastic in their praise of the content and accomplishments of the meeting, but they were equally happy about themore » genuine welcome offered to our guests by the people of Alaska. Hosting a complex event such as this summit required an army of supporting services and we were blessed to have volunteers from Fairbanks, North Pole, Anchorage and other communities throughout Alaska helping us meet these needs. This truly was an event hosted by the people of Alaska. The significance of these events cannot be overstated. The US and global communities are finally coming to the realization of the important role that the Arctic plays in international politics, economics, and science. The Arctic has experienced tremendous changes in recent years, offering new opportunities that may be addressed through international collaborations, and serious challenges that must be addressed through active investment, adaptation and national and international coordination. Over 10% of the meeting participants were indigenous peoples, from indigenous organizations or hailed from small remote communities. This is still lower than we had hoped, but it is greater participation than similar meetings have experienced in the past. It is through such engagement that we can attack problems related to the changing environment, stagnant economies, and social ills.« less

24 CFR 954.4 - Other Federal requirements.

Code of Federal Regulations, 2011 CFR

2011-04-01

... regional or village corporation as defined or established pursuant to the Alaska Native Claims Settlement..., and affordable dwelling unit in the building/complex upon completion of the project. (2) Temporary... building/complex upon completion of the project; and (D) The provisions of paragraph (e)(2)(i) of this...

NATIONAL COASTAL CONDITION REPORT IV | Science ...

EPA Pesticide Factsheets

The National Coastal Condition Report IV (NCCR IV) is the fourth in a series of environmental assessments of U.S. coastal waters and the Great Lakes. The report includes assessments of all the nation’s estuaries in the contiguous 48 states and Puerto Rico, south-eastern Alaska, Hawaii, the U.S. Virgin Islands, Guam, and American Samoa. The NCCR IV presents four main types of data: (1) coastal monitoring data, (2) coastal ocean/ offshore monitoring data, (3) offshore fisheries data, and (4) assessment and advisory data (new to NCCR IV). The NCCR IV relies heavily on coastal monitoring data from EPA’s National Coastal Assessment (NCA) to assess coastal condition by evaluating five indicators of condition—water quality, sediment quality, benthic community condition, coastal habitat loss, and fish tissue contaminants. To assess and report on the condition of the nation's coastal resources

Elucidating the Chemical Complexity of Organic Aerosol Constituents Measured During the Southeastern Oxidant and Aerosol Study (SOAS)

NASA Astrophysics Data System (ADS)

Yee, L.; Isaacman, G. A.; Spielman, S. R.; Worton, D. R.; Zhang, H.; Kreisberg, N. M.; Wilson, K. R.; Hering, S. V.; Goldstein, A. H.

2013-12-01

Thousands of volatile organic compounds are uniquely created in the atmosphere, many of which undergo chemical transformations that result in more highly-oxidized and often lower vapor pressure species. These species can contribute to secondary organic aerosol, a complex mixture of organic compounds that is still not chemically well-resolved. Organic aerosol collected on filters taken during the Southeastern Oxidant and Aerosol Study (SOAS) constitute hundreds of unique chemical compounds. Some of these include known anthropogenic and biogenic tracers characterized using standardized analytical techniques (e.g. GC-MS, UPLC, LC-MS), but the majority of the chemical diversity has yet to be explored. By employing analytical techniques involving sample derivatization and comprehensive two-dimensional gas chromatography (GC x GC) with high-resolution-time-of-flight mass spectrometry (HR-ToF-MS), we elucidate the chemical complexity of the organic aerosol matrix along the volatility and polarity grids. Further, by utilizing both electron impact (EI) and novel soft vacuum ultraviolet (VUV) ionization mass spectrometry, a greater fraction of the organic mass is fully speciated. The GC x GC-HR-ToF-MS with EI/VUV technique efficiently provides an unprecedented level of speciation for complex ambient samples. We present an extensive chemical characterization and quantification of organic species that goes beyond typical atmospheric tracers in the SOAS samples. We further demonstrate that complex organic mixtures can be chemically deconvoluted by elucidation of chemical formulae, volatility, functionality, and polarity. These parameters provide insight into the sources (anthropogenic vs. biogenic), chemical processes (oxidation pathways), and environmental factors (temperature, humidity), controlling organic aerosol growth in the Southeastern United States.

Bedrock geologic map of the northern Alaska Peninsula area, southwestern Alaska

USGS Publications Warehouse

Wilson, Frederic H.; Blodgett, Robert B.; Blome, Charles D.; Mohadjer, Solmaz; Preller, Cindi C.; Klimasauskas, Edward P.; Gamble, Bruce M.; Coonrad, Warren L.

2017-03-03

The northern Alaska Peninsula is a region of transition from the classic magmatic arc geology of the Alaska Peninsula to a Proterozoic and early Paleozoic carbonate platform and then to the poorly understood, tectonically complex sedimentary basins of southwestern Alaska. Physiographically, the region ranges from the high glaciated mountains of the Alaska-Aleutian Range to the coastal lowlands of Cook Inlet on the east and Bristol Bay on the southwest. The lower Ahklun Mountains and finger lakes on the west side of the map area show strong effects from glaciation. Structurally, a number of major faults cut the map area. Most important of these are the Bruin Bay Fault that parallels the coast of Cook Inlet, the Lake Clark Fault that cuts diagonally northeast to southwest across the eastern part of the map area, and the presently active Holitna Fault to the northwest that cuts surficial deposits.Distinctive rock packages assigned to three provinces are overlain by younger sedimentary rocks and intruded by widely dispersed latest Cretaceous and (or) early Tertiary granitic rocks. Much of the east half of the map area lies in the Alaska-Aleutian Range province; the Jurassic to Tertiary Alaska-Aleutian Range batholith and derivative Jurassic sedimentary rocks form the core of this province, which is intruded and overlain by the Aleutian magmatic arc. The Lime Hills province, the carbonate platform, occurs in the north-central part of the map area. The Paleozoic and Mesozoic Ahklun Mountains province in the western part of the map area includes abundant chert, argillite, and graywacke and lesser limestone, basalt, and tectonic mélange. The Kuskokwim Group, an Upper Cretaceous turbidite sequence, is extensively exposed and bounds all three provinces in the west-central part of the map area.

The distribution of seabirds and fish in relation to ocean currents in the southeastern Chukchi Sea

USGS Publications Warehouse

Piatt, John F.; Wells, John L.; MacCharles, Andrea; Fadely, Brian S.; Montevecchi, W.A.; Gaston, A.J.

1991-01-01

In late August 1988, we studied the distribution of seabirds in the southeastern Chukchi Sea, particularly in waters near a major seabird colony at Cape Thompson. Foraging areas were characterized using hydrographic data obtained from hydroacoustic surveys for fish. Murres (Uria spp.) and Black-legged Kitttiwakes Rissa tridactyla breeding at Cape Thompson fed mostly on Arctic cod, which are known from previous studies to be the most abundant pelagic fish in the region. Our hydroacoustic surveys revealed that pelagic fish were distributed widely, but densities were estimated to be low (e.g., 0.1-10 g∙m-3) throughout the study area and a few schools were recorded. Large feeding flocks of murres and kittiwakes were observed over fish schools with densities estimated to exceed 15 g∙m-3. Fish densities were higher in shallow Alaska Coastal Current waters than offshore in Bering Sea waters, and most piscivorous seabirds foraged in coastal waters. Poor kittiwake breeding success and a low frequency of fish in murre and kittiwake stomachs in late August suggested that fish densities were marginal for sustaining breeding seabirds at that time. Planktivorous Least Auklets Aethia pusilla and Parakeet Auklets Cyclorrhynchus psittacula foraged almost exclusively in Bering Sea waters. Short-tailed Shearwaters Puffinus tenuirostris and Tufted Puffins Fratercula cirrhata foraged in transitional waters at the front between Coastal and Bering Sea currents.

Complete mitochondrial genome of a Pleistocene jawbone unveils the origin of polar bear.

PubMed

Lindqvist, Charlotte; Schuster, Stephan C; Sun, Yazhou; Talbot, Sandra L; Qi, Ji; Ratan, Aakrosh; Tomsho, Lynn P; Kasson, Lindsay; Zeyl, Eve; Aars, Jon; Miller, Webb; Ingólfsson, Olafur; Bachmann, Lutz; Wiig, Oystein

2010-03-16

The polar bear has become the flagship species in the climate-change discussion. However, little is known about how past climate impacted its evolution and persistence, given an extremely poor fossil record. Although it is undisputed from analyses of mitochondrial (mt) DNA that polar bears constitute a lineage within the genetic diversity of brown bears, timing estimates of their divergence have differed considerably. Using next-generation sequencing technology, we have generated a complete, high-quality mt genome from a stratigraphically validated 130,000- to 110,000-year-old polar bear jawbone. In addition, six mt genomes were generated of extant polar bears from Alaska and brown bears from the Admiralty and Baranof islands of the Alexander Archipelago of southeastern Alaska and Kodiak Island. We show that the phylogenetic position of the ancient polar bear lies almost directly at the branching point between polar bears and brown bears, elucidating a unique morphologically and molecularly documented fossil link between living mammal species. Molecular dating and stable isotope analyses also show that by very early in their evolutionary history, polar bears were already inhabitants of the Artic sea ice and had adapted very rapidly to their current and unique ecology at the top of the Arctic marine food chain. As such, polar bears provide an excellent example of evolutionary opportunism within a widespread mammalian lineage.

Complete mitochondrial genome of a Pleistocene jawbone unveils the origin of polar bear

PubMed Central

Lindqvist, Charlotte; Schuster, Stephan C.; Sun, Yazhou; Talbot, Sandra L.; Qi, Ji; Ratan, Aakrosh; Tomsho, Lynn P.; Kasson, Lindsay; Zeyl, Eve; Aars, Jon; Miller, Webb; Ingólfsson, Ólafur; Bachmann, Lutz; Wiig, Øystein

2010-01-01

The polar bear has become the flagship species in the climate-change discussion. However, little is known about how past climate impacted its evolution and persistence, given an extremely poor fossil record. Although it is undisputed from analyses of mitochondrial (mt) DNA that polar bears constitute a lineage within the genetic diversity of brown bears, timing estimates of their divergence have differed considerably. Using next-generation sequencing technology, we have generated a complete, high-quality mt genome from a stratigraphically validated 130,000- to 110,000-year-old polar bear jawbone. In addition, six mt genomes were generated of extant polar bears from Alaska and brown bears from the Admiralty and Baranof islands of the Alexander Archipelago of southeastern Alaska and Kodiak Island. We show that the phylogenetic position of the ancient polar bear lies almost directly at the branching point between polar bears and brown bears, elucidating a unique morphologically and molecularly documented fossil link between living mammal species. Molecular dating and stable isotope analyses also show that by very early in their evolutionary history, polar bears were already inhabitants of the Artic sea ice and had adapted very rapidly to their current and unique ecology at the top of the Arctic marine food chain. As such, polar bears provide an excellent example of evolutionary opportunism within a widespread mammalian lineage. PMID:20194737

Black and Brown Bear Activity at Selected Coastal Sites in Glacier Bay National Park and Preserve, Alaska: A Preliminary Assessment Using Noninvasive Procedures

USGS Publications Warehouse

Partridge, Steve; Smith, Tom; Lewis, Tania

2009-01-01

A number of efforts in recent years have sought to predict bear activity in various habitats to minimize human disturbance and bear/human conflicts. Alaskan coastal areas provide important foraging areas for bears (Ursus americanus and U. arctos), particularly following den emergence when there may be no snow-free foraging alternatives. Additionally, coastal areas provide important food items for bears throughout the year. Glacier Bay National Park and Preserve (GLBA) in southeastern Alaska has extensive coastal habitats, and the National Park Service (NPS) has been long interested in learning more about the use of these coastal habitats by bears because these same habitats receive extensive human use by park visitors, especially kayaking recreationists. This study provides insight regarding the nature and intensity of bear activity at selected coastal sites within GLBA. We achieved a clearer understanding of bear/habitat relationships within GLBA by analyzing bear activity data collected with remote cameras, bear sign mapping, scat collections, and genetic analysis of bear hair. Although we could not quantify actual levels of bear activity at study sites, agreement among measures of activity (for example, sign counts, DNA analysis, and video record) lends support to our qualitative site assessments. This work suggests that habitat evaluation, bear sign mapping, and periodic scat counts can provide a useful index of bear activity for sites of interest.

Towards Understanding the Timing and Frequency of Rain-on-Snow (ROS) Events in Alaska

NASA Astrophysics Data System (ADS)

Pan, C.; Kirchner, P. B.; Kimball, J. S.; Kim, Y.; Kamp, U.

2017-12-01

Rain-on-snow (ROS) events affect ecosystem processes at multiple spatial and temporal scales including hydrology, carbon cycling, wildlife movement and human transportation and result in marked changes to snowpack processes including enhanced snow melt, surface albedo and energy balance. Changes in the surface structure of the snowpack are visible through optical remote sensing and changes in the relative content and distribution of water, air and ice in the snowpack are detectable using passive microwave remote sensing. This project aims to develop ROS products to elucidate changes in frequency and distribution in ROS events using satellite data products derived from both optical and passive microwave satellite records. To detect ROS events, we use downscaled brightness temperature measurements derived from vertical and horizontal polarizations at 19 and 37 GHz from the Advanced Microwave Scanning Radiometer (AMSR-E/2) passive microwave satellites. Preliminary results indicate an overall classification accuracy of 77.6% relative to in situ weather observations including surface air temperature, precipitation, and snow depth. ROS events are spatially distributed largely to elevations below 500 m and occur most frequently on northern to western aspects in addition to southeastern. Regional ROS hot spots occur in southwest Alaska characterized by warmer climates and transient snowcover. The seasonal timing of ROS events indicates increasing frequency during the fall and spring months.

The distribution of Δ14C in Korea from 2010 to 2013

NASA Astrophysics Data System (ADS)

Park, J. H.; Hong, W.; Xu, X.; Park, G.; Sung, K. S.; Sung, Kilho; Lee, Jong-geol; Nakanishi, T.; Park, Hyo-Seok

2015-10-01

Δ14C values of leaves of a deciduous tree record to those of atmospheric CO2 within error and were used to map out Δ14C distribution in Korea. We collected ginkgo (Ginkgo biloba Linnaeus, a deciduous tree) leaf samples in mid-June to early July from 2009 to 2013 in Korea to obtain the regional distribution of Δ14C. Commonly CO2 emitted from fossil fuel consumption dilutes atmospheric 14C, while operations and accidents at nuclear power plants can increase it. The distribution maps of Δ14C from 2010 to 2013 in Korea shows that Δ14C values in the northwestern and southeastern parts of Korea are lower than those of the other parts of Korea, which is consistent with the population and industry patterns. Decrease rates of annually averaged Δ14C values in Korea over the study period are larger than those of Pt. Barrow, Alaska, USA (71.3°N, 156.5°W), so the difference between them and those of Pt. Barrow, Alaska, USA became larger annually. This may be due to the increase in fossil fuel consumption in Korea and China. The decrease rate between 2010 and 2011 was smaller than in other years. This could be the effect of the Fukushima power plant accident which occurred in March 11, 2011, but further study is needed to clarify it.

Identification, definition and mapping of terrestrial ecosystems in interior Alaska

NASA Technical Reports Server (NTRS)

Anderson, J. H. (Principal Investigator)

1973-01-01

The author has identified the following significant results. A reconstituted, simulated color-infrared print, enlarged to a scale of 1:250,000, was used to make a vegetation map of a 3,110 sq km area just west of Fairbanks, Alaska. Information was traced from the print which comprised the southeastern part of ERTS-1 scene 1033-21011. A 1:1,000,000 scale color-infrared transparency of this scene, obtained from NASA, was used along side the print as an aid in recognizing colors, color intensities and blends, and mosaics of different colors. Color units on the transparency and print were identified according to vegetation types using NASA air photos, U.S. Forest Service air photos, and experience of the investigator. Five more or less pure colors were identified and associated with vegetation types. These colors were designated according to their appearances on the print: (1) orange for forest vegetation dominated by broad-leaved trees: (2) gray for forest vegetation dominated by needle-leaved trees; (3) violet for scrub vegetation; (4) light violet denoting herbaceous tundra vegetation; and (5) dull violet for muskeg vegetation. This study has shown, through close examinations of the NASA transparency, that much more detailed vegetation landscape, or ecosystem maps could be produced, if only spectral signatures could be consistently and reliably recognized and transferred to a map of suitable scale.

Use of nearshore and estuarine areas by gray whales (Eschrichtius robustus) in the eastern Bering Sea

USGS Publications Warehouse

Gill, Robert E.; Hall, John D.

1983-01-01

During spring aerial surveys of the coast of the southeastern Bering Sea significant numbers of gray whales were seen in nearshore waters along the north side of the Alaska Peninsula. Many (50-80%) of these animals were observed surfacing with mud trails or lying on their sides, characteristics both associated with feeding. A migration route close to shore (within 1-2 km) was used until whales neared Egegik Bay, where they began to head west 5-8 km offshore, across northern Bristol Bay. Smaller numbers of gray whales were present throughout summer in nearshore waters and estuaries along the north side of the Alaska Peninsula. At Nelson Lagoon gray whales normally used the lagoon in spring, were absent during early summer, returned in mid-summer, and then were present until late November when they departed for the wintering grounds. Gray whales were present in the lagoon most often during periods of peak tidal flow; those that appeared to be feeding were oriented into the current. Three behaviors that appeared to be associated with feeding were observed: side-feeding from a stationary position within shallow waters of lagoon channels, diving within the lagoon and in nearshore waters, and elliptical side-feeding in the surf zone along the outer coast. Large crustaceans of the genus Crangon were available to and probably eaten by gray whales at Nelson Lagoon.

Complete mitochondrial genome of a Pleistocene jawbone unveils the origin of polar bear

USGS Publications Warehouse

Lindqvist, Charlotte; Schuster, Stephan C.; Sun, Yazhou; Talbot, Sandra L.; Qi, Ji; Ratan, Aakrosh; Tomsho, Lynn P.; Kasson, Lindsay; Zeyl, Eve; Aars, Jon; Miller, Webb; Ingólfsson, Ólafur; Bachmann, Lutz; Wiig, Øystein

2010-01-01

The polar bear has become the flagship species in the climate-change discussion. However, little is known about how past climate impacted its evolution and persistence, given an extremely poor fossil record. Although it is undisputed from analyses of mitochondrial (mt) DNA that polar bears constitute a lineage within the genetic diversity of brown bears, timing estimates of their divergence have differed considerably. Using next-generation sequencing technology, we have generated a complete, high-quality mt genome from a stratigraphically validated 130,000- to 110,000-year-old polar bear jawbone. In addition, six mt genomes were generated of extant polar bears from Alaska and brown bears from the Admiralty and Baranof islands of the Alexander Archipelago of southeastern Alaska and Kodiak Island. We show that the phylogenetic position of the ancient polar bear lies almost directly at the branching point between polar bears and brown bears, elucidating a unique morphologically and molecularly documented fossil link between living mammal species. Molecular dating and stable isotope analyses also show that by very early in their evolutionary history, polar bears were already inhabitants of the Artic sea ice and had adapted very rapidly to their current and unique ecology at the top of the Arctic marine food chain. As such, polar bears provide an excellent example of evolutionary opportunism within a widespread mammalian lineage.

Observations On Some Upper Amazonian Wetlands of Southeastern Peru

NASA Astrophysics Data System (ADS)

Householder, J. E.; Muttiah, R.; Khanal, S.

2007-05-01

Upper Amazonian wetlands represent little studied, poorly understood, and grossly under protected systems. Scientific investigation of Amazonian wetlands is in its infancy; nor is there much known about their ecological services. Regionally, wetlands form a ubiquitous and significant component of floodplain habitat fed by perennial springs as well as overland runoff. Locally, wetland vegetation forms bewilderingly complex vegetation mosaics that seem to be governed by local topography and hydrology. Drawing upon intensive field campaigns and remotely sensed imagery, we summarize the results and experiences gathered in wetlands of southeastern Peru.

Anatomy of a metamorphic core complex: seismic refraction/wide-angle reflection profiling in southeastern California and western Arizona

USGS Publications Warehouse

McCarthy, J.; Larkin, S.P.; Fuis, G.S.; Simpson, R.W.; Howard, K.A.

1991-01-01

The metamorphic core complex belt in southeastern California and western Arizona is a NW-SE trending zone of unusually large Tertiary extension and uplift. Midcrustal rocks exposed in this belt raise questions about the crustal thickness, crustal structure, and the tectonic evolution of the region. Three seismic refraction/wide-angle reflection profiles were collected to address these issues. The results presented here, which focus on the Whipple and Buckskin-Rawhide mountains, yield a consistent three-dimensiional image of this part of the metamorphic core complex belt. The final model consists of a thin veneer (<2 km) of upper plate and fractured lower plate rocks (1.5-5.5 km s-1) overlying a fairly homogeneous basement (~6.0 km s-1) and a localized high-velocity (6.4 km s -1) body situated beneath the western Whipple Mountains. A prominent midcrustal reflection is identified beneath the Whipple and Buckskin Rawhide mountains between 10 and 20km depth. -from Authors

Monoterpenes are the largest source of summertime organic aerosol in the southeastern United States

DOE PAGES

Zhang, Haofei; Yee, Lindsay D.; Lee, Ben H.; ...

2018-02-12

The chemical complexity of atmospheric organic aerosol (OA) has caused substantial uncertainties in understanding its origins and environmental impacts. Here, we provide constraints on OA origins through compositional characterization with molecular-level details. Our results suggest that secondary OA (SOA) from monoterpene oxidation accounts for approximately half of summertime fine OA in Centreville, AL, a forested area in the southeastern United States influenced by anthropogenic pollution. We find that different chemical processes involving nitrogen oxides, during days and nights, play a central role in determining the mass of monoterpene SOA produced. These findings elucidate the strong anthropogenic–biogenic interaction affecting ambient aerosolmore » in the southeastern United States and point out the importance of reducing anthropogenic emissions, especially under a changing climate, where biogenic emissions will likely keep increasing.« less

Monoterpenes are the largest source of summertime organic aerosol in the southeastern United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Haofei; Yee, Lindsay D.; Lee, Ben H.

The chemical complexity of atmospheric organic aerosol (OA) has caused substantial uncertainties in understanding its origins and environmental impacts. Here, we provide constraints on OA origins through compositional characterization with molecular-level details. Our results suggest that secondary OA (SOA) from monoterpene oxidation accounts for approximately half of summertime fine OA in Centreville, AL, a forested area in the southeastern United States influenced by anthropogenic pollution. We find that different chemical processes involving nitrogen oxides, during days and nights, play a central role in determining the mass of monoterpene SOA produced. These findings elucidate the strong anthropogenic–biogenic interaction affecting ambient aerosolmore » in the southeastern United States and point out the importance of reducing anthropogenic emissions, especially under a changing climate, where biogenic emissions will likely keep increasing.« less

Modeling vulnerability to thermokarst disturbance and its consequences on regional land cover dynamic in boreal Alaska

NASA Astrophysics Data System (ADS)

Genet, H.; Lara, M. J.; Bolton, W. R.; McGuire, A. D.

2016-12-01

Estimation of the magnitude and consequences of permafrost degradation in high latitude is one of the most urgent research challenges related to contemporary and future climate change. In addition to widespread vertical degradation, ice-rich permafrost can thaw laterally, often triggering abrupt subsidence of the ground surface called thermokart. In this depression, permafrost plateau vegetation will transition to wetlands or lakes, while surface water of the surrounding landscape may drain towards it. These abrupt changes in land cover and hydrology can have dramatic consequences from wildlife habitat and biogeochemical cycles. Although recent studies have documented an acceleration of the rates of thermokarst formation in boreal and arctic peatlands, the importance of thermokarst at the regional level is still poorly understood. To better understand the vulnerability of the landscape to thermokarst disturbance in Alaska, we developed the Alaska Thermokarst Model (ATM), a state-and-transition model designed to simulate land cover change associated with thermokarst disturbance. In boreal regions, the model simulates transitions from permafrost plateau forest to thermokarst lake, bog or fen, as a function of climate and fire dynamics, permafrost characteristics and physiographic information. This model is designed and parameterized based on existing literature and a new repeated imagery analysis we conducted in a major wetland complex in boreal Alaska. We will present simulation and validation of thermokarst dynamic and associated land cover change in two wetland complexes in boreal Alaska, from 2000 to 2100 for six climate scenarios associating three AR5 emission scenarios and two global circulation model simulations. By 2100, ATM is predicting decrease between 3.5 and 9.1 % in the extent of permafrost plateau forest, mostly to the benefit of thermokarst fen, and lake. This analysis allowed us to assess the importance of thermokarst dynamics and landscape evolution associated with permafrost thaw in vulnerable regions of boreal Alaska during the 21st century and could be used as a baseline for managers to incorporate projected land cover changes in designing land management strategies.

Environmental Impact Statement for the Modernization and Enhancement of Ranges, Airspace, and Training Areas in the Joint Pacific Alaska Range Complex in Alaska. Volume 1 - Executive Summary, Chapters 1 through 10

DTIC Science & Technology

2013-06-01

to short-term behavioral responses and no effects that would be measurable at a population level have been documented. Fish in their native...the sustainable multipurpose use of natural resources (hunting, fishing , trapping, and non- consumptive uses) on military lands, subject to safety...support fish populations year-round, as they freeze in winter or when iced over and lack sufficient dissolved oxygen for fish to survive (USARAK 2004-1

Okefenokee Swamp Fire, Georgia

NASA Image and Video Library

2002-05-22

Large smoke plumes were produced by the Blackjack complex fire in southeastern Georgia Okefenokee Swamp as seen by the MISR instrument aboard NASA Terra spacecraft May 8, 2002. 3D glasses are necessary to view this image.

Genetic differentiation of Alaska Chinook salmon: the missing link for migratory studies.

PubMed

Templin, William D; Seeb, James E; Jasper, James R; Barclay, Andrew W; Seeb, Lisa W

2011-03-01

Most information about Chinook salmon genetic diversity and life history originates from studies from the West Coast USA, western Canada and southeast Alaska; less is known about Chinook salmon from western and southcentral Alaska drainages. Populations in this large area are genetically distinct from populations to the south and represent an evolutionary legacy of unique genetic, phenotypic and life history diversity. More genetic information is necessary to advance mixed stock analysis applications for studies involving these populations. We assembled a comprehensive, open-access baseline of 45 single nucleotide polymorphisms (SNPs) from 172 populations ranging from Russia to California. We compare SNP data from representative populations throughout the range with particular emphasis on western and southcentral Alaska. We grouped populations into major lineages based upon genetic and geographic characteristics, evaluated the resolution for identifying the composition of admixtures and performed mixed stock analysis on Chinook salmon caught incidentally in the walleye pollock fishery in the Bering Sea. SNP data reveal complex genetic structure within Alaska and can be used in applications to address not only regional issues, but also migration pathways, bycatch studies on the high seas, and potential changes in the range of the species in response to climate change. © 2011 Blackwell Publishing Ltd.

Mapping Phyllic and Argillic-Altered Rocks in Southeastern Afghanistan using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Data

USGS Publications Warehouse

Mars, John L.; Rowan, Lawrence C.

2007-01-01

Introduction: ASTER data and logical operators were successfully used to map phyllic and argillic-altered rocks in the southeastern part of Afghanistan. Hyperion data were used to correct ASTER band 5 and ASTER data were georegistered to orthorectified Landsat TM data. Logical operator algorithms produced argillic and phyllic byte ASTER images that were converted to vector data and overlain on ASTER and Landsat TM images. Alteration and fault patterns indicated that two areas, the Argandab igneous complex, and the Katawaz basin may contain potential polymetallic vein and porphyry copper deposits. ASTER alteration mapping in the Chagai Hills indicates less extensive phyllic and argillic-altered rocks than mapped in the Argandab igneous complex and the Katawaz basin and patterns of alteration are inconclusive to predict potential deposit types.

Ages and origin of felsic rocks from the Eastern Erenhot ophiolitic complex, southeastern Central Asian Orogenic Belt, Inner Mongolia China

NASA Astrophysics Data System (ADS)

Yang, Jinfu; Zhang, Zhicheng; Chen, Yan; Yu, Haifei; Qian, Xiaoyan

2017-08-01

The Central Asian Orogenic Belt (CAOB) is known for its massive Phanerozoic generation of juvenile crust. The tectonic evolution of the CAOB during the late Paleozoic era is still debated. The Eastern Erenhot ophiolite complex (EOC) has been recognized as one of the numerous late Paleozoic ophiolitic blocks in the southeastern part of the CAOB. Zircon U-Pb dating on rhyolite and plagiogranite from the EOC yielded a tight range of ages from 360 to 348 Ma, indicating that the complex formed in the early Carboniferous. The primitive mantle-normalized spider diagram of rhyolites (εNd(t) values of +6.8 and +7) and basalts almost overlaps. Such rhyolites may have been derived from partial melting of juvenile basaltic rocks during the initial opening of the Erenhot-Hegenshan oceanic basin. All of the plagiogranites exhibit similar trace element behaviours of High Field-Strength Elements, such as U, Zr and Hf, and Large Ion Lithophile Elements, such as Ba and Rb, to these of gabbros. These plagiogranites were considered products of episodes of partial melting of hydrous gabbros during ocean floor spreading. We conclude that the northern subduction of the Paleo-Asian Ocean stopped before 360 Ma and the southeastern CAOB experienced extension during the late Paleozoic era. The Erenhot-Hegenshan Ocean, which is comparable to the present Red Sea, originated from syn-collisional crustal thickening, subsequent lithosphere extension, and upwelling of the asthenosphere during orogenic quiescence with an age of 20 Ma.

Care, food consumption, and behavior of bald eagles used in DDT tests

USGS Publications Warehouse

Chura, N.J.; Stewart, P.A.

1967-01-01

Twenty-seven Bald Eagles captured in southeastern Alaska were used in feeding tests to determine the effects of DDT in the diet.....Trapping and housing of eagles are discussed. Various aspects of eagle behavior and handling techniques are also presented. Recommendations are made for preventing injuries and increasing the comfort of captive birds.....The 1962 test birds consumed an average of 274 grams per bird day with a range of 109 to 401 grams per day between birds. Average food intake was 254 grams per bird day for the 1963 test birds with a range of 194 to 324 grams per day between birds.....Weight losses varied from 23 to 49 per cent of normal body weight for the 7 birds which died in the 1962 tests. Tremors and death occurred first for birds on the highest dosage and progressively later for birds on the lower dosages.

LANDSAT digital analysis of the initial recovery of the Kokolik River tundra fire area, Alaska

NASA Technical Reports Server (NTRS)

Hall, D. K.; Ormsby, J. P.; Johnson, L.; Brown, J. (Principal Investigator)

1979-01-01

The author has identified the following significant results. Considerable regrowth of vegetation was observed between August 1977 and August 1978, both in the field and through analysis of LANDSAT near infrared digital data. The spectral reflectances in the burned areas were found to increase with the age of the burn in a one year period due to vegetation regrowth. Regrowth was particularly evident in the lightly burned portions of the burned area. Image analysis techniques using the AOIPS system permitted delineation of burn severity categories. The conditions and type of ground cover prior to the fire influenced the severity of burning, as did the direction of the winds while the burning was in progress as determined from field and LANDSAT observations. More severe burning was induced by winds blowing in the northeastern and southeastern portions of the burned area.

Using an Interdisciplinary Approach to Teach About Climate Change

NASA Astrophysics Data System (ADS)

Schafer, K.; Spenner, C.

2017-12-01

The traditional methods of teaching science, or any particular discipline, are not necessarily well suited for preparing students to solve big messy problems like sustainable development, climate change and resource management. We have developed a summer course entitled, "Human Ecology: Our Place in Nature," with the goal of addressing such issues through a series of case studies. The goal of these case studies is to explore how people interact with nature through Agriculture, Fisheries and Energy Use issues and could easily be adapted to specific geographical regions with different land use challenges. The course was divided into two segments: the first took place at locations near our school in San Jose, California and the second piece at various locations in Southeastern Alaska. Students learned about the interdisciplinary nature of these issues and developed an individual project of their choosing to explore some aspect of the course in greater depth.

Potential effects of temperature on the benthic infaunal community on the southeastern Bering Sea shelf: Possible impacts of climate change

NASA Astrophysics Data System (ADS)

Coyle, K. O.; Konar, B.; Blanchard, A.; Highsmith, R. C.; Carroll, J.; Carroll, M.; Denisenko, S. G.; Sirenko, B. I.

2007-11-01

In the late 1950s, Soviet researchers collected benthic infaunal samples from the southeastern Bering Sea shelf. Approximately 17 years later, researchers at University of Alaska Fairbanks also sampled the region to assess infaunal biomass and abundance. Here, the two data sets were examined to document patterns and reveal any consistent differences in infaunal biomass among major feeding groups between the two time periods. No significant differences in the geometric mean biomass of all taxa pooled were indicated between the two study periods (1958-1959=49.1 g m -2; 1975-1976=60.8 g m -2; P=0.14); however, significant differences were observed for specific functional groups, namely carnivores, omnivores and surface detritivores. Of the 64 families identified from both data sets from all functional groups, 21 showed statistically significant ( P⩽0.05) differences in mean biomass. Of the 21 families showing significant differences, 19 (91%) of the families had higher mean biomass in the 1975-1976 data set. The above differences suggest a trend toward higher overall infaunal biomass for specific functional groups during mid 1970s compared with the late 1950s. Temperature measurements and literature data indicate that the mid-1970s was an unusually cold period relative to the period before and after, suggesting a mechanistic link between temperature changes and infaunal biomass. Food-web relationships and ecosystem dynamics in the southeastern Bering Sea indicate that during cold periods, infaunal biomass will be elevated relative to warm periods due to elevated carbon flux to the benthos and exclusion of benthic predators on infaunal invertebrates by the cold bottom water on the shelf. As long-term observations of temperature and sea-ice cover indicate a secular warming trend on the Bering Sea shelf, the potential changes in food-web relationships could markedly alter trophic structure and energy flow to apex consumers, potentially impacting the commercial, tourist and subsistence economies.

Using a Complexity-Based Perspective to Better Understand the Relationships among Mentoring, School Conflicts, and Novice Retention

ERIC Educational Resources Information Center

Waterman, Sheryn Elaine Spencer

2011-01-01

In this study I used complexity-thinking, ecologically-based sustainable capacity-building, narrative methodology, and pragmatism to explore the relationships among mentoring, conflict, and novice retention. In order to explore these relationships, I constructed stories from my interviews with six mentor-novice dyads in a southeastern 9-12 high…

Early retreat of the Alaska Peninsula Glacier Complex and the implications for coastal migrations of First Americans

USGS Publications Warehouse

Misarti, Nicole; Finney, Bruce P.; Jordan, James W.; Maschner, Herbert D. G.; Addison, Jason A.; Shapley, Mark D.; Krumhardt, Andrea P.; Beget, James E.

2012-01-01

The debate over a coastal migration route for the First Americans revolves around two major points: seafaring technology, and a viable landscape and resource base. Three lake cores from Sanak Island in the western Gulf of Alaska yield the first radiocarbon ages from the continental shelf of the Northeast Pacific and record deglaciation nearly 17 ka BP (thousands of calendar years ago), much earlier than previous estimates based on extrapolated data from other sites outside the coastal corridor in the Gulf of Alaska. Pollen data suggest an arid, terrestrial ecosystem by 16.3 ka BP. Therefore glaciers would not have hindered the movement of humans along the southern edge of the Bering Land Bridge for two millennia before the first well-recognized “New World” archaeological sites were inhabited.

Emission Factors for CO2, CO, CH4, and C2 - C4 Hydrocarbons from the 2011 Great Dismal Swamp, Virginia Fire

NASA Astrophysics Data System (ADS)

Baker, S.; Soja, A. J.; Richardson, M. J.

2012-12-01

With a warming climate, increased dry conditions and drought periods are likely to result in higher fire activity in the wetlands of the eastern and southeastern US. Fires in this fuel type can smolder for months producing significant carbon release and major impacts on air quality. While a comprehensive set of emission factors has been established for most US fuel types, a less complete set is available for emissions where deep layers of organic matter can consume and smolder for days, weeks and months. Lightning started the Lateral West fire in the Great Dismal Swamp National Wildlife Refuge, Virginia on August 4, and it burned slowly through drought-stressed hardwood forest and dry peat soil. The fire produced dense plumes of smoke that mostly dispersed over the Atlantic Ocean, but also affected air quality as far away as Washington, D.C. Fire emissions were sampled August 26, 2011. The fire had burned 6,358 acres. and was smoldering along in the peat, with some brush still igniting. The average emission factors (EF) we measured from the sampling were 1441 g/kg CO2, 192 g/kg CO; and 16.5 g/kg CH4.. Modified combustion efficiency (MCE) was 0.83, produced by the small amount of flaming combustion mixed with smoldering combustion of the peat. The CO2 EF values are similar to those measured from smoldering duff in Alaska in 2003 (1436 g/kg), and the CO EF was lower than Alaska (244 g/kg CO), while the CH4 EF was much higher than Alaska (8.4 g/kg CH4). We will present our complete set of emission factors from the Great Dismal Swamp for CO2, CO, CH4, and C2 - C4 hydrocarbons, and contrast these results with other fuel types. Linear regressions of C1- C4 hydrocarbons vs. CO concentration will presented and compared with other emissions results.

Malaspina Glacier, Alaska

NASA Image and Video Library

2017-12-08

The ice of a piedmont glacier spills from a steep valley onto a relatively flat plain, where it spreads out unconstrained like pancake batter. Elephant Foot Glacier in northeastern Greenland is an excellent example; it is particularly noted for its symmetry. But the largest piedmont glacier in North America (and possibly the world) is Malaspina in southeastern Alaska. On September 24, 2014, the Operational Land Imager (OLI) on Landsat 8 acquired this image of Malaspina Glacier. The main source of ice comes from Seward Glacier, located at the top-center of this image. The Agassiz and Libbey glaciers are visible on the left side, and the Hayden and Marvine glaciers are on the right. The brown lines on the ice are moraines—areas where soil, rock, and other debris have been scraped up by the glacier and deposited at its sides. Where two glaciers flow together, the moraines merge to form a medial moraine. Glaciers that flow at a steady speed tend to have moraines that are relatively straight. But what causes the dizzying pattern of curves, zigzags, and loops of Malaspina’s moraines? Glaciers in this area of Alaska periodically “surge,”meaning they lurch forward quickly for one to several years. As a result of this irregular flow, the moraines at the edges and between glaciers can become folded, compressed, and sheared to form the characteristic loops seen on Malaspina. For instance, a surge in 1986 displaced moraines on the east side of Malaspina by as much as 5 kilometers (3 miles). NASA Earth Observatory image by Jesse Allen, using Landsat data from the U.S. Geological Survey. Caption by Kathryn Hansen. Credit: NASA Earth Observatory NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

ARC-2010-ACD10-0244-011

NASA Image and Video Library

2010-12-28

A Minotaur IV rocket, carrying NASA's Organism/Organic Exposure to Orbital Stresses (O/OREOS) nano satellite launches from the Alaska Aerospace Corporation's Kodiak Launch Complex on Nov. 19, 2010. Image credit: NASA/Matthew Daniels

Collisional Tectonics of the Saint Elias Orogen, Alaska, Observed by GPS

NASA Astrophysics Data System (ADS)

Elliott, J. L.; Freymueller, J. T.; Larsen, C. F.

2005-12-01

The Saint Elias orogen of south central Alaska and the adjacent area of Canada is the highest coastal mountain range on earth, with peaks that exceed 6000 meters in elevation. It is located in the complex transition zone between transform motion along the Queen Charlotte-Fairweather fault system and subduction along the Aleutian Megathrust. The Yakutat terrane lies in the gap between the end of the Megathrust and the end of the transform system. Roughly 4 cm/yr of convergence is accommodated within the continental crust, onshore and possibly offshore, as the Yakutat terrane collides with southern Alaska. This collision provides the driving force behind the stunning topographic relief of the orogen. As part of the STEEP project designed to unravel the tectonic complexities of this region, we made GPS measurements at 47 sites in south central Alaska during the summer of 2005. Here we present results from 13 campaign GPS sites that had prior measurements. The span of measurements at these campaign sites range from one to twelve years. All of the sites show northwestward motion and uplift. The highest amounts of uplift occur at several coastal sites near Icy Bay where average rates surpass 24 mm/yr. Further north, sites along the Bagley Icefield display an average uplift rate of about 20 mm/yr. A significant portion of this uplift is caused by the melting of regional icefields and the redistribution of mass in large glacier systems such as the Bering Glacier. We also examine the impact of the Denali Fault earthquake on the rates of motion in this area.

Building University Capacity to Visualize Solutions to Complex Problems in the Arctic

NASA Astrophysics Data System (ADS)

Broderson, D.; Veazey, P.; Raymond, V. L.; Kowalski, K.; Prakash, A.; Signor, B.

2016-12-01

Rapidly changing environments are creating complex problems across the globe, which are particular magnified in the Arctic. These worldwide challenges can best be addressed through diverse and interdisciplinary research teams. It is incumbent on such teams to promote co-production of knowledge and data-driven decision-making by identifying effective methods to communicate their findings and to engage with the public. Decision Theater North (DTN) is a new semi-immersive visualization system that provides a space for teams to collaborate and develop solutions to complex problems, relying on diverse sets of skills and knowledge. It provides a venue to synthesize the talents of scientists, who gather information (data); modelers, who create models of complex systems; artists, who develop visualizations; communicators, who connect and bridge populations; and policymakers, who can use the visualizations to develop sustainable solutions to pressing problems. The mission of Decision Theater North is to provide a cutting-edge visual environment to facilitate dialogue and decision-making by stakeholders including government, industry, communities and academia. We achieve this mission by adopting a multi-faceted approach reflected in the theater's design, technology, networking capabilities, user support, community relationship building, and strategic partnerships. DTN is a joint project of Alaska's National Science Foundation Experimental Program to Stimulate Competitive Research (NSF EPSCoR) and the University of Alaska Fairbanks (UAF), who have brought the facility up to full operational status and are now expanding its development space to support larger team science efforts. Based in Fairbanks, Alaska, DTN is uniquely poised to address changes taking place in the Arctic and subarctic, and is connected with a larger network of decision theaters that include the Arizona State University Decision Theater Network and the McCain Institute in Washington, DC.

Affects of Changes in Sea Ice Cover on Bowhead Whales and Subsistence Whaling in the Western Arctic

NASA Astrophysics Data System (ADS)

Moore, S.; Suydam, R.; Overland, J.; Laidre, K.; George, J.; Demaster, D.

2004-12-01

Global warming may disproportionately affect Arctic marine mammals and disrupt traditional subsistence hunting activities. Based upon analyses of a 24-year time series (1979-2002) of satellite-derived sea ice cover, we identified significant positive trends in the amount of open-water in three large and five small-scale regions in the western Arctic, including habitats where bowhead whales (Balaena mysticetus) feed or are suspected to feed. Bowheads are the only mysticete whale endemic to the Arctic and a cultural keystone species for Native peoples from northwestern Alaska and Chukotka, Russia. While copepods (Calanus spp.) are a mainstay of the bowhead diet, prey sampling conducted in the offshore region of northern Chukotka and stomach contents from whales harvested offshore of the northern Alaskan coast indicate that euphausiids (Thysanoessa spp.) advected from the Bering Sea are also common prey in autumn. Early departure of sea ice has been posited to control availability of zooplankton in the southeastern Bering Sea and in the Cape Bathurst polynya in the southeastern Canadian Beaufort Sea, with maximum secondary production associated with a late phytoplankton bloom in insolatoin-stratified open water. While it is unclear if declining sea-ice has directly affected production or advection of bowhead prey, an extension of the open-water season increases opportunities for Native subsistence whaling in autumn. Therefore, bowhead whales may provide a nexus for simultaneous exploration of the effects sea ice reduction on pagophillic marine mammals and on the social systems of the subsistence hunting community in the western Arctic. The NOAA/Alaska Fisheries Science Center and NSB/Department of Wildlife Management will investigate bowhead whale stock identity, seasonal distribution and subsistence use patterns during the International Polar Year, as an extension of research planned for 2005-06. This research is in response to recommendations from the Scientific Committee of the International Whaling Commission. Research plans include biopsy sampling and subsequent genetic analyses, long-term acoustic detection and satellite tracking of whales in selected portions of their range coupled with community-based management of the subsistence harvest. This research, in concert with extension of oceanographic observing capabilities, promises to elucidate underlying forcing mechanisms key to the changing high-Arctic marine ecosystem.

Within-stand variation in understorey vegetation affects fire behaviour in longleaf pine xeric sandhills

Treesearch

Evelyn S. Wenk; G. Geoff Wang; Joan L. Walker

2011-01-01

The frequent fires typical of the longleaf pine ecosystem in the south-eastern USA are carried by live understorey vegetation and pine litter. Mature longleaf pine stands in the xeric sandhills region have a variable understory vegetation layer, creating several fuel complexes at the within-stand scale (20 m2). We identified three fuel complexes...

50 CFR 217.77 - Renewal of a Letter of Authorization and adaptive management.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS REGULATIONS... to Space Vehicle and Missile Launches at Kodiak Launch Complex, Alaska § 217.77 Renewal of a Letter...

50 CFR 217.77 - Renewal of a Letter of Authorization and adaptive management.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS REGULATIONS... to Space Vehicle and Missile Launches at Kodiak Launch Complex, Alaska § 217.77 Renewal of a Letter...

50 CFR 217.77 - Renewal of a Letter of Authorization and adaptive management.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS REGULATIONS... to Space Vehicle and Missile Launches at Kodiak Launch Complex, Alaska § 217.77 Renewal of a Letter...

50 CFR 217.77 - Renewal of a Letter of Authorization and adaptive management.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS REGULATIONS... to Space Vehicle and Missile Launches at Kodiak Launch Complex, Alaska § 217.77 Renewal of a Letter...

Field-trip guide to volcanic and volcaniclastic deposits of the lower Jurassic Talkeetna formation, Sheep Mountain, south-central Alaska

USGS Publications Warehouse

Draut, Amy E.; Clift, Peter D.; Blodgett, Robert B.

2006-01-01

This guide provides information for a one-day field trip in the vicinity of Sheep Mountain, just north of the Glenn Highway in south-central Alaska. The Lower Jurassic Talkeetna Formation, consisting of extrusive volcanic and volcaniclastic sedimentary rocks of the Talkeetna arc complex, is exposed on and near Sheep Mountain. Field-trip stops within short walking distance of the Glenn Highway (approximately two hours’ drive from Anchorage) are described, which will be visited during the Geological Society of America Penrose meeting entitled Crustal Genesis and Evolution: Focus on Arc Lower Crust and Shallow Mantle, held in Valdez, Alaska, in July 2006. Several additional exposures of the Talkeetna Formation on other parts of Sheep Mountain that would need to be accessed with longer and more strenuous walking or by helicopter are also mentioned.

Permian Tethyan Fusulinina from the Kenai Peninsula, Alaska

USGS Publications Warehouse

Stevens, C.H.; Davydov, V.I.; Bradley, D.

1997-01-01

Two samples from a large, allochthonous limestone block in the McHugh Complex of the Chugach terrane on the Kenai Peninsula, Alaska, contain species of 12 genera of Permian Fusulinina including Abadehella, Kahlerina, Pseudokahlerina?, Nankinella, Codonofusiella, Dunbarula, Parafusulina?, Chusenella, Verbeekina, Pseudodoliolina, Metadoliolina?, Sumatrina?, and Yabeina, as well as several other foraminiferans and one alga. The assemblage of fusulinids is characteristically Tethyan, belonging to the Yabeina archaica zone of early Midian (late Wordian) age. Similar faunas are known from the Pamirs, Transcaucasia, and Japan, as well as from allochthonous terranes in British Columbia, northwestern Washington, and Koryakia in eastern Siberia.

50 CFR 217.70 - Specified activity and specified geographical region.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Vehicle and Missile Launches at Kodiak Launch Complex, Alaska § 217.70 Specified activity and specified... specified in paragraph (b) of this section by U.S. citizens engaged in space vehicle and missile launch...

50 CFR 217.70 - Specified activity and specified geographical region.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Vehicle and Missile Launches at Kodiak Launch Complex, Alaska § 217.70 Specified activity and specified... specified in paragraph (b) of this section by U.S. citizens engaged in space vehicle and missile launch...

50 CFR 217.70 - Specified activity and specified geographical region.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Vehicle and Missile Launches at Kodiak Launch Complex, Alaska § 217.70 Specified activity and specified... specified in paragraph (b) of this section by U.S. citizens engaged in space vehicle and missile launch...

50 CFR 217.70 - Specified activity and specified geographical region.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Vehicle and Missile Launches at Kodiak Launch Complex, Alaska § 217.70 Specified activity and specified... specified in paragraph (b) of this section by U.S. citizens engaged in space vehicle and missile launch...

Presentations - Emond, A.M. and others, 2015 | Alaska Division of

Science.gov Websites

: Download below or please see our publication sales page for more information. Quadrangle(s): Big Delta Creek Schist; Bush Prospect; Chicken Metamorphic Complex; Chicken Pluton; DIGHEM-V EM System; Delta

Status and distribution of the Kittlitz's Murrelet Brachyramphus brevirostris along the Alaska Peninsula and Kodiak and Aleutian Islands, Alaska

USGS Publications Warehouse

Madison, Erica N.; Piatt, John F.; Arimitsu, Mayumi L.; Romano, Marc D.; van Pelt, Thomas I.; Nelson, S. Kim; Williams, Jeffrey C.; DeGange, Anthony R.

2011-01-01

The Kittlitz's Murrelet Brachyramphus brevirostris is adapted for life in glacial-marine ecosystems, being concentrated in the belt of glaciated fjords in the northern Gulf of Alaska from Glacier Bay to Cook Inlet. Most of the remaining birds are scattered along coasts of the Alaska Peninsula and Aleutian Islands, where they reside in protected bays and inlets, often in proximity to remnant glaciers or recently deglaciated landscapes. We summarize existing information on Kittlitz's Murrelet in this mainly unglaciated region, extending from Kodiak Island in the east to the Near Islands in the west. From recent surveys, we estimated that ~2400 Kittlitz's Murrelets were found in several large embayments along the Alaska Peninsula, where adjacent ice fields feed silt-laden water into the bays. On Kodiak Island, where only remnants of ice remain today, observations of Kittlitz's Murrelets at sea were uncommon. The species has been observed historically around the entire Kodiak Archipelago, however, and dozens of nest sites were found in recent years. We found Kittlitz's Murrelets at only a few islands in the Aleutian chain, notably those with long complex shorelines, high mountains and remnant glaciers. The largest population (~1600 birds) of Kittlitz's Murrelet outside the Gulf of Alaska was found at Unalaska Island, which also supports the greatest concentration of glacial ice in the Aleutian Islands. Significant populations were found at Atka (~1100 birds), Attu (~800) and Adak (~200) islands. Smaller numbers have been reported from Unimak, Umnak, Amlia, Kanaga, Tanaga, Kiska islands, and Agattu Island, where dozens of nest sites have been located in recent years. Most of those islands have not been thoroughly surveyed, and significant pockets of Kittlitz's Murrelets may yet be discovered. Our estimate of ~6000 Kittlitz's Murrelets along the Alaska Peninsula and Aleutian Islands is also likely to be conservative because of the survey protocols we employed (i.e. early seasonal timing of surveys, strip transects).

Anticipating Future Extreme Climate Events for Alaska Using Dynamical Downscaling and Quantile Mapping

NASA Astrophysics Data System (ADS)

Lader, R.; Walsh, J. E.

2016-12-01

Alaska is projected to experience major changes in extreme climate during the 21st century, due to greenhouse warming and exacerbated by polar amplification, wherein the Arctic is warming at twice the rate compared to the Northern Hemisphere. Given its complex topography, Alaska displays extreme gradients of temperature and precipitation. However, global climate models (GCMs), which typically have a spatial resolution on the order of 100km, struggle to replicate these extremes. To help resolve this issue, this study employs dynamically downscaled regional climate simulations and quantile-mapping methodologies to provide a full suite of daily model variables at 20 km spatial resolution for Alaska, from 1970 to 2100. These data include downscaled products of the: ERA-Interim reanalysis from 1979 to 2015, GFDL-CM3 historical from 1970 to 2005, and GFDL-CM3 RCP 8.5 from 2006 to 2100. Due to the limited nature of long-term observations and high-resolution modeling in Alaska, these data enable a broad expansion of extremes analysis. This study uses these data to highlight a subset of the 27 climate extremes indices, previously defined by the Expert Team on Climate Change Detection and Indices, as they pertain to climate change in Alaska. These indices are based on the statistical distributions of daily surface temperature and precipitation and focus on threshold exceedance, and percentiles. For example, the annual number of days with a daily maximum temperature greater than 25°C is anticipated to triple in many locations in Alaska by the end of the century. Climate extremes can also refer to long duration events, such as the record-setting warmth that defined the 2015-16 cold season in Alaska. The downscaled climate model simulations indicate that this past winter will be considered normal by as early as the mid-2040s, if we continue to warm according to the business-as-usual RCP 8.5 emissions scenario. This represents an accelerated warming as compared to projections form the coarse scale GCMs, and this greater rate of change in the downscaled products is noted with other extremes indices as well.

HLA class II and TNF genes in African Americans from the Southeastern United States: regional differences in allele frequencies.

PubMed

Kuffner, Tamara; Whitworth, William; Jairam, Maya; McNicholl, Janet

2003-06-01

Knowledge of population major histocompatibility complex gene frequencies is important for construction of organ donor pools and for studies of disease association. Human leukocyte antigen DRB1 (HLA-DRB1), HLA-DQB1, and TNFalpha -308 (G-A) promoter genetic typing was performed in 112 healthy, unrelated African Americans (AAs) from the southeastern United States. Allele frequencies were compared with published frequency data from other AA populations. Our AA population had the highest frequency of HLA- DRB1*09 (6.7%) reported in any AA population. The frequency of the TNF alpha -308A polymorphism was also high (14.4%), when compared with published frequencies in AAs. Significant regional differences in the distribution of most HLA-DRB1 and HLA-DQB1 alleles were observed in all AA populations examined. The AA HLA-DRB1 and -DQB1 frequencies also differed from published Caucasian frequencies. This is the first report describing the distribution of TNF alpha promoter alleles in the Southeastern United States. The high DRB1*09 and TNF alpha -308A allele frequencies of our population most resemble the frequencies of these alleles in certain West African populations. These varying major histocompatibility complex gene frequencies may reflect different regional population structures among AAs in the United States, which may be due to differences in ancestral origins, migration, and racial admixture.

A geologic guide to Wrangell-Saint Elias National Park and Preserve, Alaska; a tectonic collage of northbound terranes

USGS Publications Warehouse

Winkler, Gary R.; with contributions by MacKevett, E. M.; Plafker, George; Richter, D.H.; Rosenkrans, D.S.; Schmoll, H.R.

2000-01-01

Wrangell-Saint Elias National Park and Preserve, the largest unit in the U.S. National Park System, encompasses near 13.2 million acres of geological wonderments. This geologic guide presents history of exploration and Earth-science investigation; describes the complex geologic makeup; characterizes the vast college of accretion geologic terranes in this area of Alaska's continental margin; recapitulates the effects of earthquakes, volcanoes, and glaciers; characterizes the copper and gold resources of the parklands; and describes outstanding locales within the park and preserve area. A glossary of geologic terms and a categorized list of additional sources of information complete this report.

Low prevalence of Borrelia bavariensis in Ixodes ricinus ticks in southeastern Austria.

PubMed

Glatz, Martin; Muellegger, Robert R; Hizo-Teufel, Cecilia; Fingerle, Volker

2014-10-01

Borrelia bavariensis was recently described as a distinct genospecies among the B. burgdorferi sensu lato complex. The prevalence of B. bavariensis in Austria, a highly endemic area for tick-transmitted pathogens, is scarcely characterized. To investigate the prevalence of B. bavariensis in Ixodes ricinus ticks we reevaluated the results of a study conducted in 518 ticks from southeastern Austria collected in 2002 and 2003. The presence of B. burgdorferi s.l.-specific DNA in ticks was analyzed by a PCR for the outer surface protein A (ospA) gene. Borrelia species were differentiated by restriction fragment length polymorphism (RFLP) analysis, and samples positive for B. bavariensis were further analyzed by multilocus sequence analysis. Two of 133 (1.5%) B. burgdorferi s.l.-positive I. ricinus ticks were infected with B. bavariensis. Both specimens were coinfected with the OspA serotype 5 of B. garinii. Borrelia bavariensis is present; however, seem to be rare in I. ricinus ticks in southeastern Austria. Copyright © 2014 Elsevier GmbH. All rights reserved.

Zoonotic Leprosy in the Southeastern United States

PubMed Central

Sharma, Rahul; Singh, Pushpendra; Loughry, W.J.; Lockhart, J. Mitchell; Inman, W. Barry; Duthie, Malcolm S.; Pena, Maria T.; Marcos, Luis A.; Scollard, David M.; Cole, Stewart T.

2015-01-01

Nine-banded armadillos (Dasypus novemcinctus) are naturally infected with Mycobacterium leprae and have been implicated in zoonotic transmission of leprosy. Early studies found this disease mainly in Texas and Louisiana, but armadillos in the southeastern United States appeared to be free of infection. We screened 645 armadillos from 8 locations in the southeastern United States not known to harbor enzootic leprosy for M. leprae DNA and antibodies. We found M. leprae–infected armadillos at each location, and 106 (16.4%) animals had serologic/PCR evidence of infection. Using single-nucleotide polymorphism variable number tandem repeat genotyping/genome sequencing, we detected M. leprae genotype 3I-2-v1 among 35 armadillos. Seven armadillos harbored a newly identified genotype (3I-2-v15). In comparison, 52 human patients from the same region were infected with 31 M. leprae types. However, 42.3% (22/52) of patients were infected with 1 of the 2 M. leprae genotype strains associated with armadillos. The geographic range and complexity of zoonotic leprosy is expanding. PMID:26583204

Monoterpenes are the largest source of summertime organic aerosol in the southeastern United States

EPA Science Inventory

The chemical complexity of atmospheric organic aerosol (OA) has caused substantial uncertainties in understanding its origins and environmental impacts. Here, we provide constraints on OA origins through compositional characterization with molecular-level details. Our results sug...

Unraveling tectonics and climate forcing in the late-Neogene exhumation history of South Alaska

NASA Astrophysics Data System (ADS)

Valla, Pierre; Champagnac, Jean-Daniel; Shuster, David; Herman, Frédéric; Giuditta Fellin, Maria

2015-04-01

The southern Alaska range presents an ideal setting to study the complex interactions between tectonics, climate and surface processes in landscape evolution. It exhibits active tectonics with the ongoing subduction/collision between Pacific and North America, and major active seismogenic reverse and strike-slip faults. The alpine landscape, rugged topography and the important ice-coverage at present reveal a strong glacial imprint associated with high erosion and sediment transport rates. Therefore, the relative importance of climatically-driven glacial erosion and tectonics for the observed late-exhumation history appears to be quite complex to decipher. Here, we first perform a formal inversion of an extensive bedrock thermochronological dataset from the literature to quantify the large-scale 20-Myr exhumation history over the entire southern Alaska. We show that almost half of the variability within the thermochronological record can be explained by modern annual precipitations spatial distribution, the residuals clearly evidencing localized exhumation along major tectonic structures of the frontal fold and thrust belt. Our results confirm high exhumation rates in the St Elias "syntaxis" and frontal zones for the last 0-2 Myr, where major ice fields and high precipitation rates likely sustained high exhumation rates; however the impact of late Cenozoic glaciations is difficult to constrain because of the low resolution on the exhumation history older than ~2 Myr. On the contrary, our inversion outcomes highlight that north of the Bagley Icefield the long-term exhumation has remained quite slow and continuous over the last ~20 Myr, with no late-stage signal of exhumation change since the onset of glaciations despite a clear glacial imprint on the landscape. We thus focus on the Granite Range (Wrangell-St Elias National Park, Alaska), an area presenting a strong glacial imprint but minor tectonic activity with only localized brittle deformation. We sampled four elevation profiles over an East-West transect for low-temperature thermochrometry. Apatite (U-Th-Sm)/He dating provides ages between ~10 and 30 Ma, in agreement with published data, and shows apparent low long-term exhumation rates (~0.1 km/Myr). 4He/3He thermochronometry on a subset of samples reveals a more complex exhumation history, with a significant increase in exhumation since ~6-4 Ma that we relate to the early onset of glaciations and associated glacial erosion processes. Our results, in agreement with offshore sediment records, thus confirm an early glacial activity and associated erosion response in Alaska, well before the onset of Pliocene-Pleistocene Northern Hemisphere glaciations.

Intercontinental migratory connectivity and population structuring of Dunlins from western Alaska

USGS Publications Warehouse

Gill, Robert E.; Handel, Colleen M.; Ruthrauff, Daniel R.

2013-01-01

The Dunlin (Calidris alpina) is a polytypic shorebird with complex patterns of distribution and migration throughout its holarctic range. We analyzed mark-re sighting data obtained between 1977 and 2010 from birds captured at two major staging areas in western Alaska to test the hypothesis that the migration patterns of Alaskan populations are a mixture of parallel and chain, similar to those of Dunlin populations in the western Palearctic. Birds marked on the Yukon—Kuskokwim Delta were found wintering in both Asia and North America, which documented the unexpected mixing of C. a. arcticola from northern Alaska and C. a. pacifica from western Alaska and contradicted our initial prediction of parallel migration pathways for these two subspecies. In its North American winter range C. a. pacifica segregated according to location of marking, confirming our prediction of a chain migration pattern within this population. Individuals of C. a. pacifica marked on the delta were resighted significantly farther north, mostly in southern British Columbia and Washington, than birds marked on the second, more southerly staging area on the Alaska Peninsula, which were resighted primarily in the San Francisco Bay area of northern California. We recommend additional studies use a combination of intrinsic and extrinsic markers to quantify the strength of migratory connectivity between breeding, staging, and wintering areas. Such information is needed to guide conservation efforts because the Dunlin and other waterbirds are losing intertidal habitats at an unprecedented rate and scale, particularly in the Yellow Sea and other parts of Asia.

A Framework for Conducting a National Study of Substance Abuse Treatment Programs Serving American Indian and Alaska Native Communities

PubMed Central

Novins, Douglas K.; Moore, Laurie A.; Beals, Janette; Aarons, Gregory A.; Rieckmann, Traci; Kaufman, Carol E.

2013-01-01

Background Because of their broad geographic distribution, diverse ownership and operation, and funding instability, it is a challenge to develop a framework for studying substance abuse treatment programs serving American Indian and Alaska Native communities at a national level. This is further complicated by the historic reluctance of American Indian and Alaska Native communities to participate in research. Objectives and Methods We developed a framework for studying these substance abuse treatment programs (n = 293) at a national level as part of a study of attitudes toward, and use of, evidence-based treatments among substance abuse treatment programs serving AI/AN communities with the goal of assuring participation of a broad array of programs and the communities that they serve. Results Because of the complexities of identifying specific substance abuse treatment programs, the sampling framework divides these programs into strata based on the American Indian and Alaska Native communities that they serve: (1) the 20 largest tribes (by population); (2) urban AI/AN clinics; (3) Alaska Native Health Corporations; (4) other Tribes; and (5) other regional programs unaffiliated with a specific AI/AN community. In addition, the recruitment framework was designed to be sensitive to likely concerns about participating in research. Conclusion and Scientific Significance This systematic approach for studying substance abuse and other clinical programs serving AI/AN communities assures the participation of diverse AI/AN programs and communities and may be useful in designing similar national studies. PMID:22931088

Petrology of the Plutonic Rocks of west-central Alaska

USGS Publications Warehouse

Miller, Thomas P.

1970-01-01

A series of plutons in west-central Alaska defines the Hogatza plutonic belt which extends for about 200 miles in an east-west direction from the northeastern Seward Peninsula to the Koyukuk River. The plutonic rocks have an aggregate area of about 1,200 square miles and their composition, distribution, and possible petrogenesis are discussed for the first time in this report. Field, petrographic and chemical data supported by K/Ar age dating indicate the plutonic rocks are divisible into two suites differing in age, location, and composition. The western plutons are mid-Cretaceous (~100 m.y.) in age and consist of a heterogeneous assemblage of monzonite, syenite, quartz monzonite. Associated with these granitic rocks is a group of alkaline sub-silicic rocks that forma belt of intrusive complexes extending for a distance of at least 180 miles from west-central Alaska to the Bering Sea. The complex at Granite Mountain shows a rare example of zoning from an alkaline rim to a quartz-bearing core. The occurrence of a similar complex at Cape Dezhnev on the easternmost tip of Siberia suggests the alkaline province may extend into Siberia. The easternmost plutons are Late Cretaceous (180 m.y.) in age and composed primarily of granodiorite and quartz monzonite similar to calc-alkaline plutons found throughout the North America Cordillera. The plutons are epizonal and intrude deformed but unmetamorphosed Lower Cretaceous andesitic volcanics and volcanic graywacke which constitute the highly mobile Yukon-Koyukuk volcanogenic province of west-central Alaska. No older rocks have been found within the confines of this vast tract; the occurrence of a bounding ophiolite sequence has lead to the suggestion that the province was formed by large-scale rifting and is underlain by oceanic crust. The possibility of no juvenile sialic crust over much of the area suggests that the potassium-rich magma now represented by the alkaline rocks originated in the mantle. The distribution of the alkaline rocks appears to be related to regional structural features, particularly the boundary between the Mesozoic volcanogenic province of west-central Alaska and the thrust-faulted province of metamorphic-plutonic and sedimentary rocks of Paleozoic and Precambrian age that forms the eastern Seward Peninsula. This boundary may have been a zone of structural weakness along which alkaline magma was generated. Modal and chemical trends suggest that the potassium-rich magma influenced the composition of more granitic magmas forming at higher levels. The latter may have been forming as a result of anatexis of andesite and mixing of mantle-derived mafic magma. The result is the heterogeneous assemblage of generally potassium-rich plutonic rocks that forms the west end of the Hogataza plutonic belt. The loci of magmatism in west-central Alaska shifted east in Late Cretaceous time and the eastern plutons show only local signs of potassium enrichment. They are compositionally homogeneous and differences within plutons appear due to local contamination.

Sedimentology and geomorphology of a large tsunamigenic landslide, Taan Fiord, Alaska

NASA Astrophysics Data System (ADS)

Dufresne, A.; Geertsema, M.; Shugar, D. H.; Koppes, M.; Higman, B.; Haeussler, P. J.; Stark, C.; Venditti, J. G.; Bonno, D.; Larsen, C.; Gulick, S. P. S.; McCall, N.; Walton, M.; Loso, M. G.; Willis, M. J.

2018-02-01

On 17 October 2015, a landslide of roughly 60 × 106 m3 occurred at the terminus of Tyndall Glacier in Taan Fiord, southeastern Alaska. It caused a tsunami that inundated an area over 20 km2, whereas the landslide debris itself deposited within a much smaller area of approximately 2 km2. It is a unique event in that the landslide debris was deposited into three very different environments: on the glacier surface, on land, and in the marine waters of the fjord. Part of the debris traversed the width of the fjord and re-emerged onto land, depositing coherent hummocks with preserved source stratigraphy on an alluvial fan and adjacent moraines on the far side of the fjord. Imagery from before the landslide shows that the catastrophic slope failure was preceded by deformation and sliding for at least the two decades since the glacier retreated to its current terminus location, exposing steep and extensively faulted slopes. A small volume of the total slide mass remains within the source area and is topped by striated blocks (> 10 m across) and standing trees that were transported down the slope in intact positions during the landslide. Field work was carried out in the summer of 2016, and by the time this paper was written, almost all of the supraglacial debris was advected into the fjord and half the subaerial hummocks were buried by glacial advance; this rapid change illustrates how highly active sedimentary processes in high-altitude glacial settings can skew any landslide-frequency analyses, and emphasizes the need for timely field investigations of these natural hazards.

Kilbuck terrane: oldest known rocks in Alaska

USGS Publications Warehouse

Box, S.E.; Moll-Stalcup, E. J.; Wooden, J.L.; Bradshaw, J.Y.

1990-01-01

The Kilbuck terrane in southwestern Alaska is a narrow, thin crustal sliver or flake of amphibolite facies orthogneiss. The igneous protolith of this gneiss was a suite of subduction-related plutonic rocks. U-Pb data on zircons from trondhjemitic and granitic samples yield upper-intercept (igneous) ages of 2070 ?? 16 and 2040 ?? 74 Ma, respectively. Nd isotope data from these rocks suggest that a diorite-tonalite-trondhjemite suite (??Nd[T] = +2.1 to +2.7; T is time of crystallization) evolved from partial melts of depleted mantle with no discernible contamination by older crust, whereas a coeval granitic pluton (??Nd[T] = -5.7) contains a significant component derived from Archean crust. Orthogneisses with similar age and Nd isotope characteristics are found in the Idono complex 250 km to the north. Early Proterozoic rocks are unknown elsewhere in Alaska. The possibility that the Kilbuck terrane was displaced from provinces of similar age in other cratons (e.g., Australian, Baltic, Guiana, and west African shields), or from the poorly dated Siberian craton, cannot be excluded. -from Authors

Warming and Elevated CO2 Interact to Drive Rapid Shifts in Marine Community Production.

PubMed

Sorte, Cascade J B; Bracken, Matthew E S

2015-01-01

Predicting the outcome of future climate change requires an understanding of how alterations in multiple environmental factors manifest in natural communities and affect ecosystem functioning. We conducted an in situ, fully factorial field manipulation of CO2 and temperature on a rocky shoreline in southeastern Alaska, USA. Warming strongly impacted functioning of tide pool systems within one month, with the rate of net community production (NCP) more than doubling in warmed pools under ambient CO2 levels relative to initial NCP values. However, in pools with added CO2, NCP was unaffected by warming. Productivity responses paralleled changes in the carbon-to-nitrogen ratio of a red alga, the most abundant primary producer species in the system, highlighting the direct link between physiology and ecosystem functioning. These observed changes in algal physiology and community productivity in response to our manipulations indicate the potential for natural systems to shift rapidly in response to changing climatic conditions and for multiple environmental factors to act antagonistically.

Warming and Elevated CO2 Interact to Drive Rapid Shifts in Marine Community Production

PubMed Central

Sorte, Cascade J. B.; Bracken, Matthew E. S.

2015-01-01

Predicting the outcome of future climate change requires an understanding of how alterations in multiple environmental factors manifest in natural communities and affect ecosystem functioning. We conducted an in situ, fully factorial field manipulation of CO2 and temperature on a rocky shoreline in southeastern Alaska, USA. Warming strongly impacted functioning of tide pool systems within one month, with the rate of net community production (NCP) more than doubling in warmed pools under ambient CO2 levels relative to initial NCP values. However, in pools with added CO2, NCP was unaffected by warming. Productivity responses paralleled changes in the carbon-to-nitrogen ratio of a red alga, the most abundant primary producer species in the system, highlighting the direct link between physiology and ecosystem functioning. These observed changes in algal physiology and community productivity in response to our manipulations indicate the potential for natural systems to shift rapidly in response to changing climatic conditions and for multiple environmental factors to act antagonistically. PMID:26714167

Geologic implications of topographic, gravity, and aeromagnetic data in the northern Yukon-Koyukuk province and its borderlands, Alaska

USGS Publications Warehouse

Cady, J.W.

1989-01-01

The northern Yukon-Koyukuk province is characterized by low elevation and high Bouguer gravity and aeromagnetic anomalies in contrast to the adjacent Brooks Range and Ruby geanticline. Using newly compiled digital topographic, gravity, and aeromagnetic maps, the province is divided into three geophysical domains. The Koyukuk domain, which is nearly equivalent to the Koyukuk lithotectonic terrane, is a horseshoe-shaped area, open to the south, of low topography, high gravity, and high-amplitude magnetic anomalies caused by an intraoceanic magmatic arc. The Angayucham and Kanuti domains are geophysical subdivisions of the Angayucham lithotectonic terrane that occur along the northern and southeastern margins of the Yukon-Koyukuk province, where oceanic rocks have been thrust over continental rocks of the Brooks Range and Ruby geanticline. The modeling supports, but does not prove, the hypothesis that the crust of the Kobuk-Koyukuk basin is 32-35 km thick, consisting of a tectonically thickened section of Cretaceous volcanic and sedimentary rocks and older oceanic crust. -from Author

Laurel wilt: Understanding an unusual and exotic vascular wilt disease

USDA-ARS?s Scientific Manuscript database

Laurel wilt kills American members of the Lauraceae plant family (Laurales, Magnoliid complex). These include significant components of Coastal Plain forest communities in the southeastern USA, most importantly redbay, as well as the commercial crop avocado. The disease has decimated redbay, swamp ...

Neoglacial fluctuations of terrestrial, tidewater, and calving lacustrine glaciers, Blackstone-Spencer Ice Complex, Kenai Mountains, Alaska

NASA Astrophysics Data System (ADS)

Crossen, Kristine June

1997-12-01

The glaciers surrounding the Blackstone-Spencer Ice Complex display a variety of termini types: Tebenkov, Spencer, Bartlett, Skookum, Trail, Burns, Shakespeare, Marquette, Lawrence, and Ripon glaciers end in terrestrial margins; Blackstone and Beloit glaciers have tidewater termini; and Portage Glacier has a calving lacustrine margin. In addition, steep temperature and precipitation gradients exist across the ice complex from the maritime environment of Prince William Sound to the colder, drier interior. The Neoglacial history of Tebenkov Glacier, as based on overrun trees near the terminus, shows advances ca. 250- 430 AD (calibrated date), ca. 1215-1275 AD (calibrated date), and ca. 1320-1430 AD (tree ring evidence), all intervals of glacier advance around the Gulf of Alaska. However, two tidewater glaciers in Blackstone Bay retreated from their outermost moraines by 1350 AD, apparently asynchronously with respect to the regional climate signal. The most extensive Kenai Mountain glacier expansions during Neoglaciation occurred in the late Little Ice Age. The outermost moraines are adjacent to mature forest stands and bog peats that yield dates as old as 5,600 BP. Prince William Sound glaciers advanced during two Little Ice Age cold periods, 1380-1680 and 1830-1900 AD. The terrestrial glaciers around the Blackstone-Spencer Ice Complex all built moraines during the 19th century and began retreating between 1875 and 1900 AD. Portage and Burns glaciers began retreating between 1790 and 1810 AD, but their margins remained close to the outermost moraines during the 19th century. Regional glacier fluctuations are broadly synchronous in the Gulf of Alaska region. With the exception of the two tidewater glaciers in Blackstone Bay, all glaciers in the Kenai Mountains, no matter their sizes, altitudes, orientations, or types of margins, retreated at the end of the Little Ice Age. The climate signal, especially temperature, appears to be the strongest control on glacier behavior during the last millennium.

Reconstructing the eruption magnitude and energy budgets for the pre-historic eruption of the monogenetic ˜5 ka Mt. Gambier Volcanic Complex, south-eastern Australia

NASA Astrophysics Data System (ADS)

van Otterloo, Jozua; Cas, Raymond A. F.

2013-12-01

Understanding explosive volcanic eruptions, especially phreatomagmatic eruptions, their intensities and energy budgets is of major importance when it comes to risk and hazard studies. With only a few historic occurrences of phreatomagmatic activity, a large amount of our understanding comes from the study of pre-historic volcanic centres, which causes issues when it comes to preservation and vegetation. In this research, we show that using 3D geometrical modelling it is possible to obtain volume estimates for different deposits of a pre-historic, complex, monogenetic centre, the Mt. Gambier Volcanic Complex, south-eastern Australia. Using these volumes, we further explore the energy budgets and the magnitude of this eruption (VEI 4), including dispersal patterns (eruption columns varying between 5 and 10 km, dispersed towards north-east to south), to further our understanding of intraplate, monogenetic eruptions involving phreatomagmatic activity. We also compare which thermodynamic model fits best in the creation of the maar crater of Mt. Gambier: the major-explosion-dominated model or the incremental growth model. In this case, the formation of most of the craters can best be explained by the latter model.

Magmatism and fenitization in the Cretaceous potassium-alkaline-carbonatitic complex of Ipanema São Paulo State, Brazil

NASA Astrophysics Data System (ADS)

Guarino, Vincenza; Azzone, Rogério Guitarrari; Brotzu, Pietro; de Barros Gomes, Celso; Melluso, Leone; Morbidelli, Lucio; Ruberti, Excelso; Tassinari, Colombo Celso Gaeta; Brilli, Mauro

2012-01-01

The Ipanema alkaline-carbonatitic complex is part of the Meso-Cenozoic alkaline magmatism located within the southeastern part of the Brazilian Platform. Drill-core and field sampling have indicated the occurrence of glimmerites, with subordinate shonkinites (mela-syenites), clinopyroxene-bearing glimmerites, diorites and syenites. The glimmerites are cross-cut by lamprophyric dykes and calciocarbonatites. Fenitization has deeply affected the country rocks, originating dioritic and syenitic rocks. The Ipanema rocks show a distinct potassic affinity. The initial Sr-Nd- isotopic composition of the Ipanema rocks (87Sr/86Sr = 0.70661-0.70754 and 143Nd/144Nd = 0.51169-0.51181) is similar to that of tholeiitic and potassium-rich-alkaline rocks of the Eastern Paraguay. Stable isotope data for the Ipanema calciocarbonatite suggest interaction with fluids at temperatures typical of hydrothermal stages, as hypothesized for other carbonatite complexes from southeastern Brazil. The chemical differences between the lamprophyre, glimmerites, carbonatites, apatitites and magnetitites, and the absence of marked REE enrichment in the evolved lithologies, all indicate that fractional crystallization and accumulus of liquidus phases in a magma reservoir, likely coupled with liquid immiscibility processes, may have played an important role in the genesis of the Ipanema rocks.

Potential links between onshore tectonics and terrestrial organic carbon delivery to distal submarine fan environments: IODP Site U1417, Surveyor Fan, Gulf of Alaska

NASA Astrophysics Data System (ADS)

Childress, L. B.; Ridgway, K. D.; Blair, N. E.; Bahlburg, H.; Berbel, G.; Cowan, E. A.; Forwick, M.; Gulick, S. P.; Jaeger, J. M.; Maerz, C.; McClymont, E.; Moy, C. M.; Müller, J.; Nakamura, A.; Ribeiro, F.

2013-12-01

The sedimentary record at Integrated Ocean Drilling Program (IODP) Site U1417 is particularly well preserved and permits delineation of Neogene tectonic, climatic, and terrestrial organic carbon signals. Lithofacies in the 708 m-long, cored interval can be divided into 3 sedimentary packages that we interpret as linked to the tectonic convergence of the Yakutat Terrane with, and onset of tidewater glaciation along, the continental margin of northwestern Canada and southern Alaska. Previous studies have shown that development of the Surveyor Fan system was closely linked to transport of the Yakutat Terrane and development of the Cordilleran Ice Sheet. Initial shipboard measurements of total organic carbon and observed plant and coal fragments imply good preservation of terrestrial organic matter. Furthermore, documented preservation of terrestrial organic matter in modern sediment along the southern Alaskan continental margin and sediment routing through the Surveyor Channel from the Pleistocene to modern time implies a long-term conduit for this organic material to reach the distal portion of the Surveyor Fan system. We interpret the lower units of U1417 (late Miocene) to have been deposited when the Yakutat Terrane was located offshore of northern British Columbia and/or southeastern Alaska. Northward transport of the Yakutat Terrane during the late Miocene is interpreted to have resulted in uplift and erosion of the Eocene coal-bearing Kulthieth Formation. We infer that eroded rock carbon from this formation was transported from the shelf to the earliest, or precursor to, the Surveyor Fan with depocenters infilling between seamounts. Detailed geochemical/biomarker analysis of Kulthieth Formation coals will provide a chemical fingerprint by which to identify this source of late Miocene sediment at U1417. Continued Pliocene - early Pleistocene northward convergence resulted in recycling of organic carbon from the onshore Neogene thrust belt of the Yakutat Terrane and the older uplifted parts of the Mesozoic continental margin to the distal submarine fan system. Since the early Pleistocene, the distal fan has been sourced from tidewater glaciers transporting sediment from the continental margin of south-central Alaska through the Surveyor Channel and related sediment pathways, levees, and overbank systems. We hypothesize that tectonic transport of the Yakutat Terrane and the onset of tidewater glaciation resulted in variation of the geochemical signature of ancient carbon delivered to the distal parts of the Surveyor Fan. Biomarker differences between the Neogene coal-bearing Kulthieth Formation and the Mesozoic continental strata material will allow us to confirm source material to the fan over the last ~ 10 Ma.

Mesozoic­ and Cenozoic Tectono-depositional History of the Southwestern Chukchi Borderland: Implications of Pre-Brookian Passive-margin Slope Deposits for the Jurassic Extensional Deformation of the Amerasia Basin, Arctic Ocean

NASA Astrophysics Data System (ADS)

Ilhan, I.; Coakley, B.

2016-12-01

A stratigraphic framework for offshore northwest of Alaska has been developed from multi-channel seismic reflection data and direct seismic-well ties to the late 80's Crackerjack and Popcorn exploration wells along the late Cretaceous middle Brookian unconformity. This unconformity is characterized by downlap, onlap, and bi-directional onlap of the overlying upper Brookian strata in high accommodation, and erosional incision of the underlying lower Brookian strata in low accommodation. This surface links multiple basins across the southwestern Chukchi Borderland, Arctic Ocean. The lower Brookian strata are characterized by pinch out basin geometry in which parallel-continuous reflectors show north-northeasterly progressive onlap of the younger strata onto a lower Cretaceous unconformity. These strata are subdivided into Aptian-Albian and Upper Cretaceous sections along a middle Cretaceous unconformity. The north-northeasterly thinning-by-onlap is consistent across hundreds of kilometers along the southwestern Chukchi Borderland. While this suggests a south-southwesterly regional source of sediment and transport from the Early Cretaceous Arctic Alaska-Chukotka orogens, pre-Brookian clinoform strata, underlying the lower Cretaceous unconformity angularly, have been observed for the first time in southeastern margin of the Chukchi Abyssal Plain. This suggests a change in sediment source and transport direction between the pre-Brookian and the lower Brookian strata. Although the mechanism for the accommodation is not well understood, we interpret the pre-Brookian strata as passive-margin slope deposits due to the fact that we have not observed any evidence for upper crustal tectonic deformation or syn-tectonic "growth" strata in the area. Thus, this implies that depositional history of the southwestern Chukchi Borderland post-dates the accommodation. This interpretation puts a new substantial constrain on the pre-Valanginian clockwise rotation of the Chukchi Borderland away from the East Siberian continental shelf, associated with the antecedent counter-clockwise rotation of the Arctic Alaska-Chukotka microplate away from the Canadian Arctic Islands and extensional deformation of the Amerasia Basin.

Cenozoic deformation from the Yakutat-North American collision to the eastern margin of the Northern Canadian Cordillera

NASA Astrophysics Data System (ADS)

Enkelmann, E.

2017-12-01

The western margin of the Northern Cordillera of North America is dominated by transform motion of the Yakutat microplate along the Fairweather fault system. In southeast Alaska the transform boundary changes to convergence and the oblique collision of the buoyant Yakutat microplate formed the St. Elias Mountains. One of the outstanding questions in understanding the St. Elias orogeny is how stress from the plate boundary has been transferred inboard and distributed strain in the North American plate. The timing, amount, and spatial pattern of deformation and rock exhumation have been studied using multiple thermochronology methods. Together the data reveal that Late Cenozoic deformation inboard of the Fairweather Fault and the colliding Yakutat plate corner at the St. Elias syntaxis was spatially very limited, resulting in rock exhumation within a <30 km-wide corridor north and northeast of the plate boundary. The data from this inboard region, located in Yukon and northern British Columbia, record Late Cretaceous-Early Eocene cooling associated with Cordilleran deformation, and Paleocene-Eocene cooling due to spreading-ridge subduction. In contrast, the region west of the St. Elias syntaxis is dominated by convergence, which resulted in significant Cenozoic deformation in southeastern and southern Alaska. In the St. Elias orogen itself, most of the Late Cenozoic deformation and exhumation occurs within the Yakutat microplate and its Cenozoic sedimentary cover that composes the fold-thrust belt. The efficient interaction between tectonic uplift and glacial erosion resulted in rapid exhumation (>1 km/Myr) and extreme rates (4 km/Myr) that are localized at the syntaxis region and have shifted southward over the past 10 Myr. Far-field deformation reaches more than 500 km to the northwest of the convergent margin and caused mountain building in south-central Alaska. Deformation to the northeast is unclear. New thermochronology data from the eastern margin of the Northern Canadian Cordillera (Northwest Territory) reveal exhumation during the Oligocene to early Miocene. At this time, transform motion was already dominating the plate margin in the west. The post-Cordilleran deformation at the eastern front may thus be related to mantle convection and/or stresses associated with the North Atlantic opening.

Areal distribution, thickness, mass, volume, and grain size of tephra-fall deposits from the 1992 eruptions of Crater Peak vent, Mt. Spurr Volcano, Alaska

USGS Publications Warehouse

McGimsey, Robert G.; Neal, Christina A.; Riley, Colleen M.

2001-01-01

The Crater Peak flank vent of Mount Spurr volcano erupted June 27, August 18, and September 16-17, 1992. The three eruptions were similar in intensity (vulcanian to subplinian eruption columns reaching up to 14 km Above Sea Level) and duration (3.5 to 4.0 hours) and produced tephra-fall deposits (12, 14, 15 x 106 m3 Dense Rock Equivalent [DRE]) discernible up to 1,000 km downwind. The June 27 ash cloud traveled north over the rugged, ice- and snow-covered Alaska Range. The August 18 ash cloud was carried southeastward over Anchorage, across Prince William Sound, and down the southeastern shoreline of the Gulf of Alaska. The September 16-17 ash plume was directed eastward over the Talkeetna and Wrangell mountains and into the Yukon Territory of Canada. Over 50 mass-per-unit-area (MPUA) samples were collected for each of the latter two fall deposits at distances ranging from about 2 km to 370 km downwind from the volcano. Only 10 (mostly proximal) samples were collected for the June fall deposit due to inaccessible terrain and funding constraints. MPUA data were plotted and contoured (isomass lines) to graphically display the distribution of each fall deposit. For the August and September eruptions, fallout was concentrated along a narrow (30 to 50 km wide) belt. The fallout was most concentrated (100,000 to greater than 250,000 g/m2) within about 80 km of the volcano. Secondary maxima occur at 200 km (2,620 g/m2) and 300 km (4,659 g/m2), respectively, down axis for the August and September deposits. The maxima contain bimodal grain size distributions (with peaks at 88.4 and 22.1 microns) indicating aggregation within the ash cloud. Combined tephra-volume for the 1992 Mount Spurr eruptions (41 x 106 m3 DRE) is comparable to that (tephra-fall only) of the 1989-90 eruptions of nearby Redoubt volcano (31-49 x 106 m3 DRE).

Stress distribution along the Fairweather-Queen Charlotte transform fault system

USGS Publications Warehouse

Bufe, C.G.

2005-01-01

Tectonic loading and Coulomb stress transfer are modeled along the right-lateral Fairweather-Queen Charlotte transform fault system using a threedimensional boundary element program. The loading model includes slip below 12 km along the transform as well as motion of the Pacific plate, and it is consistent with most available Global Positioning System (GPS) displacement rate data. Coulomb stress transfer is shown to have been a weak contributing factor in the failure of the southeastern (Sitka) segment of the Fairweather fault in 1972, hastening the occurrence of the earthquake by only about 8 months. Failure of the Sitka segment was enhanced by a combination of cumulative loading from below (95%) by slip of about 5 cm/yr since 1848, by stress transfer (about 1%) from major earthquakes on straddling segments of the Queen Charlotte fault (M 8.1 in 1949) and the Fairweather fault (M 7.8 in 1958), and by viscoelastic relaxation (about 4%) following the great 1964 Alaska earthquake, modeled by Pollitz et al. (1998). Cumulative stress increases in excess of 7 MPa at a depth of 8 km are projected prior to the M 7.6 earthquake. Coulomb stress transferred by the rupture of the great M 9.2 Alaska earthquake in 1964 (Bufe, 2004a) also hastened the occurrence of the 1972 event, but only by a month or two. Continued tectonic loading over the last half century and stress transfer from the M 7.6 Sitka event has resulted in restressing of the adjacent segments by about 3 MPa at 8 km depth. The occurrence of a M 6.8 earthquake on the northwestern part of the Queen Charlotte fault on 28 June 2004, the largest since 1949, also suggests increased stress. The Cape St. James segment of the fault immediately southeast of the 1949 Queen Charlotte rupture has accumulated about 6 MPa at 8 km through loading since 1900 and stress transfer in 1949. A continued rise in earthquake hazard is indicated for the Alaska panhandle and Queen Charlotte Islands region in the decades ahead as the potential for damaging earthquakes increases.

High shrew diversity on Alaska's Seward Peninsula: Community assembly and environmental change

USGS Publications Warehouse

Hope, Andrew G.

2012-01-01

In September 2010, 6 species of shrews (genus: Sorex) were collected at a single locality on the Seward Peninsula of Alaska. Such high sympatric diversity within a single mammalian genus is seldom realized. This phenomenon at high latitudes highlights complex Arctic community dynamics that reflect significant turnover through time as a consequence of environmental change. Each of these shrew species occupies a broad geographic distribution collectively spanning the entire Holarctic, although the study site lies within Eastern Beringia, near the periphery of all individual ranges. A review of published genetic evidence reflects a depauperate shrew community within ice-free Beringia through the last glaciation, and recent assembly of current diversity during the Holocene.

KSC01KODI037

NASA Image and Video Library

2001-05-29

KODIAK ISLAND, Alaska -- The Orbis 21D Equipment Section Boost Motor, the second stage of the Athena 1 launch vehicle, waits for the first stage, Castor 120, to be towed up the steepest part of the road, as preparations to launch Kodiak Star proceed. The first orbital launch to take place from Alaska's Kodiak Launch Complex, Kodiak Star is scheduled to lift off on a Lockheed Martin Athena I launch vehicle on Sept. 17 during a two-hour window that extends from 5:00 to 7:00 p.m. ADT. The payloads aboard include the Starshine 3, sponsored by NASA, and the PICOSat, PCSat and Sapphire, sponsored by the Department of Defense (DoD) Space Test Program.

Cytogeography of the Humifusa clade of Opuntia s.s. Mill. 1754 (Cactaceae, Opuntioideae, Opuntieae): correlations with pleistocene refugia and morphological traits in a polyploid complex

PubMed Central

Majure, Lucas C.; Judd, Walter S.; Soltis, Pamela S.; Soltis, Douglas E.

2012-01-01

Abstract Ploidy has been well studied and used extensively in the genus Opuntia to determine species boundaries, detect evidence of hybridization, and infer evolutionary patterns. We carried out chromosome counts for all members of the Humifusa clade to ascertain whether geographic patterns are associated with differences in ploidy. We then related chromosomal data to observed morphological variability, polyploid formation, and consequently the evolutionary history of the clade. We counted chromosomes of 277 individuals from throughout the ranges of taxa included within the Humifusa clade, with emphasis placed on the widely distributed species, Opuntia humifusa (Raf.) Raf., 1820 s.l. and Opuntia macrorhiza Engelm., 1850 s.l. We also compiled previous counts made for species in the clade along with our new counts to plot geographic distributions of the polyploid and diploid taxa. A phylogeny using nuclear ribosomal ITS sequence data was reconstructed to determine whether ploidal variation is consistent with cladogenesis. We discovered that diploids of the Humifusa clade are restricted to the southeastern United States (U.S.), eastern Texas, and southeastern New Mexico. Polyploid members of the clade, however, are much more widely distributed, occurring as far north as the upper midwestern U.S. (e.g., Michigan, Minnesota, Wisconsin). Morphological differentiation, although sometimes cryptic, is commonly observed among diploid and polyploid cytotypes, and such morphological distinctions may be useful in diagnosing possible cryptic species. Certain polyploid populations of Opuntia humifusa s.l. and Opuntia macrorhiza s.l., however, exhibit introgressive morphological characters, complicating species delineations. Phylogenetically, the Humifusa clade forms two subclades that are distributed, respectively, in the southeastern U.S. (including all southeastern U.S. diploids, polyploid Opuntia abjecta Small, 1923, and polyploid Opuntia pusilla (Haw.) Haw., 1812) and the southwestern U.S. (including all southwestern U.S. diploids and polyploids). In addition, tetraploid Opuntia humifusa s.l., which occurs primarily in the eastern U.S., is resolved in the southwestern diploid clade instead of with the southeastern diploid clade that includes diploid Opuntia humifusa s.l. Our results not only provide evidence for the polyphyletic nature of Opuntia humifusa and Opuntia macrorhiza, suggesting that each of these represents more than one species, but also demonstrate the high frequency of polyploidy in the Humifusa clade and the major role that genome duplication has played in the diversification of this lineage of Opuntia s.s. Our data also suggest that the southeastern and southwestern U.S. may represent glacial refugia for diploid members of this clade and that the clade as a whole should be considered a mature polyploid species complex. Widespread polyploids are likely derivatives of secondary contact among southeastern and southwestern diploid taxa as a result of the expansion and contraction of suitable habitat during the Pleistocene following glacial and interglacial events. PMID:24260652

NERACOOS | weather | ocean | marine forecast | waves | buoy | marine

Science.gov Websites

to address today's highly complex ocean and coastal challenges through integrated graduate education Avery Point campus faculty, staff and students carry out cutting-edge research in coastal oceanography Ocean Data Products team Regional Coastal Observing Systems: Alaska * Pacific Northwest * Central and

Gravity and Aeromagnetic Gradients within the Yukon-Tanana Upland, Black Mountain Tectonic Zone, Big Delta Quadrangle, east-central Alaska

USGS Publications Warehouse

Saltus, R.W.; Day, W.C.

2006-01-01

The Yukon-Tanana Upland is a complex composite assemblage of variably metamorphosed crystalline rocks with strong North American affinities. At the broadest scale, the Upland has a relatively neutral magnetic character. More detailed examination, however, reveals a fundamental northeast-southwest-trending magnetic gradient, representing a 20-nT step (as measured at a flight height of 300 m) with higher values to the northwest, that extends from the Denali fault to the Tintina fault and bisects the Upland. This newly recognized geophysical gradient is parallel to, but about 100 km east of, the Shaw Creek fault. The Shaw Creek fault is mapped as a major left-lateral, strike-slip fault, but does not coincide with a geophysical boundary. A gravity gradient coincides loosely with the southwestern half of the magnetic gradient. This gravity gradient is the eastern boundary of a 30-mGal residual gravity high that occupies much of the western and central portions of the Big Delta quadrangle. The adjacent lower gravity values to the east correlate, at least in part, with mapped post-metamorphic granitic rocks. Ground-based gravity and physical property measurements were made in the southeastern- most section of the Big Delta quadrangle in 2004 to investigate these geophysical features. Preliminary geophysical models suggest that the magnetic boundary is deeper and more fundamental than the gravity boundary. The two geophysical boundaries coincide in and around the Tibbs Creek region, an area of interest to mineral exploration. A newly mapped tectonic zone (the Black Mountain tectonic zone of O'Neill and others, 2005) correlates with the coincident geophysical boundaries.

Investigating the complex viral community of the turkey gut: an update from the laboratory and the field

USDA-ARS?s Scientific Manuscript database

Periodic monitoring of poultry flocks in the United States via molecular diagnostic methods has revealed a number of potential enteric viral pathogens in continuous circulation in turkeys and chickens. Recently, numerous enteric samples collected from turkey flocks in the southeastern United States ...

Individual sugar and acid composition within southeastern peach germplasm

USDA-ARS?s Scientific Manuscript database

eaches grown in the southeast are valued for their acidic, sweet flavor. A complex mixture of various sugars and acids at different ratios play a key role in determining these unique peach flavor attributes. To understand the flavor profile of fresh market peaches, individual sugar and acid compone...

EarthScope's Plate Boundary Observatory in Alaska: Building on Existing Infrastructure to Provide a Platform for Integrated Research and Hazard-monitoring Efforts

NASA Astrophysics Data System (ADS)

Boyce, E. S.; Bierma, R. M.; Willoughby, H.; Feaux, K.; Mattioli, G. S.; Enders, M.; Busby, R. W.

2014-12-01

EarthScope's geodetic component in Alaska, the UNAVCO-operated Plate Boundary Observatory (PBO) network, includes 139 continuous GPS sites and 41 supporting telemetry relays. These are spread across a vast area, from northern AK to the Aleutians. Forty-five of these stations were installed or have been upgraded in cooperation with various partner agencies and currently provide data collection and transmission for more than one group. Leveraging existing infrastructure normally has multiple benefits, such as easier permitting requirements and costs savings through reduced overall construction and maintenance expenses. At some sites, PBO-AK power and communications systems have additional capacity beyond that which is needed for reliable acquisition of GPS data. Where permits allow, such stations could serve as platforms for additional instrumentation or real-time observing needs. With the expansion of the Transportable Array (TA) into Alaska, there is increased interest to leverage existing EarthScope resources for station co-location and telemetry integration. Because of the complexity and difficulty of long-term O&M at PBO sites, however, actual integration of GPS and seismic equipment must be considered on a case-by-case basis. UNAVCO currently operates two integrated GPS/seismic stations in collaboration with the Alaska Earthquake Center, and three with the Alaska Volcano Observatory. By the end of 2014, PBO and TA plan to install another four integrated and/or co-located geodetic and seismic systems. While three of these are designed around existing PBO stations, one will be a completely new TA installation, providing PBO with an opportunity to expand geodetic data collection in Alaska within the limited operations and maintenance phase of the project. We will present some of the design considerations, outcomes, and lessons learned from past and ongoing projects to integrate seismometers and other instrumentation at PBO-Alaska stations. Developing the PBO network as a platform for ongoing research and hazard monitoring equipment may also continue to serve the needs of the research community and the public beyond the sun-setting and completion of EarthScope science plan in 2018.

Geological analysis of aeromagnetic data from southwestern Alaska: implications for exploration in the area of the Pebble porphyry Cu-Au-Mo deposit

USGS Publications Warehouse

Anderson, Eric D.; Hitzman, Murray W.; Monecke, Thomas; Bedrosian, Paul A.; Shah, Anjana K.; Kelley, Karen D.

2013-01-01

Aeromagnetic data are used to better understand the geology and mineral resources near the Late Cretaceous Pebble porphyry Cu-Au-Mo deposit in southwestern Alaska. The reduced-to-pole (RTP) transformation of regional-scale aeromagnetic data shows that the Pebble deposit is within a cluster of magnetic anomaly highs. Similar to Pebble, the Iliamna, Kijik, and Neacola porphyry copper occurrences are in magnetic highs that trend northeast along the crustal-scale Lake Clark fault. A high-amplitude, short- to moderate-wavelength anomaly is centered over the Kemuk occurrence, an Alaska-type ultramafic complex. Similar anomalies are found west and north of Kemuk. A moderate-amplitude, moderate-wavelength magnetic low surrounded by a moderate-amplitude, short-wavelength magnetic high is associated with the gold-bearing Shotgun intrusive complex. The RTP transformation of the district-scale aeromagnetic data acquired over Pebble permits differentiation of a variety of Jurassic to Tertiary magmatic rock suites. Jurassic-Cretaceous basalt and gabbro units and Late Cretaceous biotite pyroxenite and granodiorite rocks produce magnetic highs. Tertiary basalt units also produce magnetic highs, but appear to be volumetrically minor. Eocene monzonite units have associated magnetic lows. The RTP data do not suggest a magnetite-rich hydrothermal system at the Pebble deposit. The 10-km upward continuation transformation of the regional-scale data shows a linear northeast trend of magnetic anomaly highs. These anomalies are spatially correlated with Late Cretaceous igneous rocks and in the Pebble district are centered over the granodiorite rocks genetically related to porphyry copper systems. The spacing of these anomalies is similar to patterns shown by the numerous porphyry copper deposits in northern Chile. These anomalies are interpreted to reflect a Late Cretaceous magmatic arc that is favorable for additional discoveries of Late Cretaceous porphyry copper systems in southwestern Alaska.

Examining mechanisms in the final stages of the elimination of boreal tree species on vulnerable sites in boreal Alaska

NASA Astrophysics Data System (ADS)

Juday, G. P.; Jess, R.; Alix, C. M.; Verbyla, D.

2015-12-01

The boreal forest of Alaska and western Canada exist in a complex mosaic of environments determined by elevation, aspect of exposure, and longitudinal and latitudinal gradients of change from warm, dry continental to maritime-influenced conditions. This forest region is largely made up of trees with two growth responses to temperature increases. Trees that decrease in growth are termed negative responders, and occupy warm, dry sites at low elevations. Trees that increase in radial growth are termed positive responders, and are largely in western Alaska, and at high elevation of the Brooks and Alaska Ranges. Since the Pacific climate regime shift of the 1970s, mature trees at low elevation sites have experienced increasing climate stress in several quasi-decadal cycles of intensifying drought stress. NDVI trends and tree ring records demonstrating radial growth decline are coherent. Phenological monitoring of spruce height growth also indicates that depletion of spring soil moisture is a critical process driven by the interaction of early warm season temperatures and precipitation. Novel biotic disturbance agents including spruce budworm, outbreaks of which are triggered by warm temperature anomalies related to its biology, and aspen leaf miner are depressing realized growth below climatically predicted levels, suggesting a pathway by which tree death is likely to occur before absolute temperature limits. As a result, insect outbreaks are degrading the otherwise strong long-term climate signal in Alaska boreal trees. However, young tree (> 40 yrs.) regeneration generally does not yet display the symptoms of acute high temperature stress. Overall, on these vulnerable sites, if temperature increases similar to the past 40 years continue, long term survival prospects are questionable because the climate conditions would be outside the limits that have historically defined the species ranges of aspen, Alaska birch, and black and white spruce.

50 CFR 217.72 - Permissible methods of taking.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 50 Wildlife and Fisheries 10 2013-10-01 2013-10-01 false Permissible methods of taking. 217.72 Section 217.72 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC... Kodiak Launch Complex, Alaska § 217.72 Permissible methods of taking. (a) Under a Letter of Authorization...

50 CFR 217.72 - Permissible methods of taking.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 50 Wildlife and Fisheries 10 2012-10-01 2012-10-01 false Permissible methods of taking. 217.72 Section 217.72 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC... Kodiak Launch Complex, Alaska § 217.72 Permissible methods of taking. (a) Under a Letter of Authorization...

575 Tlingit Verbs: A Study of Tlingit Verb Paradigms

ERIC Educational Resources Information Center

Eggleston, Keri M.

2013-01-01

The Tlingit language, indigenous to Southeast Alaska and neighboring parts of British Columbia and the Yukon territory, is related to the Athabascan languages and the recently extinct language Eyak. Like Athabascan and Eyak, Tlingit verbal morphology is highly complex. The conjugation of Tlingit verbs is unpredictable in certain respects, making…

Environmental Assessment of the Kodiak Launch Complex, Kodiak Island, Alaska

DTIC Science & Technology

1996-05-01

Pasagshak State Recreation Area, a small park containing seven campsites, picnic areas, potable water and latrines , is approximately 10 kilometers (6 miles...rookeries near the proposed KLC site on Narrow Cape. The two closest major rookeries are at Marmot Island [approximately 88 kilometers (55 miles) north of

77 FR 77076 - Environmental Impacts Statements; Notice of Availability

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-31

...-557-5107. EIS No. 20120397, Final EIS, BLM, AK, National Petroleum Reserve-- Alaska (NPR-A) Integrated.... EIS No. 20120398, Final EIS, NPS, WI, Ice Age Complex at Cross Plains General Management Plan... Flood Risk in the Sutter Basin, Sutter and Butte Counties, CA, Comment Period Ends: 02/13/2013, Contact...

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Vegetation and paleoclimate of the last interglacial period, central Alaska

USGS Publications Warehouse

Muhs, D.R.; Ager, T.A.; Beget, J.E.

2001-01-01

The last interglacial period is thought to be the last time global climate was significantly warmer than present. New stratigraphic studies at Eva Creek, near Fairbanks, Alaska indicate a complex last interglacial record wherein periods of loess deposition alternated with periods of soil formation. The Eva Forest Bed appears to have formed about the time of or after deposition of the Old Crow tephra (dated to ??? 160 to ??? 120 ka), and is therefore correlated with the last interglacial period. Pollen, macrofossils, and soils from the Eva Forest Bed indicate that boreal forest was the dominant vegetation and precipitation may have been greater than present around Fairbanks during the peak of the last interglacial period. A new compilation of last interglacial localities indicates that boreal forest was extensive over interior Alaska and Yukon Territory. Boreal forest also extended beyond its present range onto the Seward and Baldwin Peninsulas, and probably migrated to higher elevations, now occupied by tundra, in the interior. Comparison of last interglacial pollen and macrofossil data with atmospheric general circulation model results shows both agreement and disagreement. Model results of warmer-than-present summers are in agreement with fossil data. However, numerous localities with boreal forest records are in conflict with model reconstructions of an extensive cool steppe in interior Alaska and much of Yukon Territory during the last interglacial. ?? 2000 Elsevier Science Ltd.

Small Mammals as Indicators of Climate, Biodiversity, and Ecosystem Change

USGS Publications Warehouse

Hope, Andrew G.; Waltari, Eric; Morse, Nathan R.; Flamme, M.J.; Cook, Joseph A.; Talbot, Sandra L.

2017-01-01

Climate is a driving evolutionary force for biodiversity in high-latitude Alaska. This region is complex and dynamic with high annual variation in temperature and light. Through deeper time, Alaska has experienced major climate extremes over much longer periodicity. For example, the Quaternary Period (the last ~2.5 million years), commonly known as the Ice Age, was punctuated by more than 20 major glacial-interglacial cycles. During glacial phases, water was locked up in ice sheets that covered much of North America, and the resulting lower sea levels exposed a land connection between Alaska and Siberia, a combined region known as Beringia (Figure 1). This isthmus provided vast expanses of land for species to inhabit, provided they could withstand potentially harsh polar conditions. Each extended glacial phase periodically transitioned into a shorter interglacial warm phase. These climate reversals melted continental ice sheets to expose corridors for reinvasion of terrestrial species, particularly those associated with forested habitats further south. Those species that survived at northern latitudes through repeated glacial-interglacial cycles formed the Arctic tundra communities that persist today. At present, Alaska supports diverse communities associated with both tundra and forests (Figure 2). These communities often interact with one another across latitudinal and elevational gradients, with tundra species generally found further north or higher in elevation. Alaska’s climate is continuing to change today, strongly influencing local environments and the distribution and dynamics of wildlife species.

A Conceptual Model of Natural and Anthropogenic Drivers and Their Influence on the Prince William Sound, Alaska, Ecosystem

PubMed Central

Harwell, Mark A.; Gentile, John H.; Cummins, Kenneth W.; Highsmith, Raymond C.; Hilborn, Ray; McRoy, C. Peter; Parrish, Julia; Weingartner, Thomas

2010-01-01

Prince William Sound (PWS) is a semi-enclosed fjord estuary on the coast of Alaska adjoining the northern Gulf of Alaska (GOA). PWS is highly productive and diverse, with primary productivity strongly coupled to nutrient dynamics driven by variability in the climate and oceanography of the GOA and North Pacific Ocean. The pelagic and nearshore primary productivity supports a complex and diverse trophic structure, including large populations of forage and large fish that support many species of marine birds and mammals. High intra-annual, inter-annual, and interdecadal variability in climatic and oceanographic processes as drives high variability in the biological populations. A risk-based conceptual ecosystem model (CEM) is presented describing the natural processes, anthropogenic drivers, and resultant stressors that affect PWS, including stressors caused by the Great Alaska Earthquake of 1964 and the Exxon Valdez oil spill of 1989. A trophodynamic model incorporating PWS valued ecosystem components is integrated into the CEM. By representing the relative strengths of driver/stressors/effects, the CEM graphically demonstrates the fundamental dynamics of the PWS ecosystem, the natural forces that control the ecological condition of the Sound, and the relative contribution of natural processes and human activities to the health of the ecosystem. The CEM illustrates the dominance of natural processes in shaping the structure and functioning of the GOA and PWS ecosystems. PMID:20862192

A Conceptual Model of Natural and Anthropogenic Drivers and Their Influence on the Prince William Sound, Alaska, Ecosystem.

PubMed

Harwell, Mark A; Gentile, John H; Cummins, Kenneth W; Highsmith, Raymond C; Hilborn, Ray; McRoy, C Peter; Parrish, Julia; Weingartner, Thomas

2010-07-01

Prince William Sound (PWS) is a semi-enclosed fjord estuary on the coast of Alaska adjoining the northern Gulf of Alaska (GOA). PWS is highly productive and diverse, with primary productivity strongly coupled to nutrient dynamics driven by variability in the climate and oceanography of the GOA and North Pacific Ocean. The pelagic and nearshore primary productivity supports a complex and diverse trophic structure, including large populations of forage and large fish that support many species of marine birds and mammals. High intra-annual, inter-annual, and interdecadal variability in climatic and oceanographic processes as drives high variability in the biological populations. A risk-based conceptual ecosystem model (CEM) is presented describing the natural processes, anthropogenic drivers, and resultant stressors that affect PWS, including stressors caused by the Great Alaska Earthquake of 1964 and the Exxon Valdez oil spill of 1989. A trophodynamic model incorporating PWS valued ecosystem components is integrated into the CEM. By representing the relative strengths of driver/stressors/effects, the CEM graphically demonstrates the fundamental dynamics of the PWS ecosystem, the natural forces that control the ecological condition of the Sound, and the relative contribution of natural processes and human activities to the health of the ecosystem. The CEM illustrates the dominance of natural processes in shaping the structure and functioning of the GOA and PWS ecosystems.

Genetics, recruitment, and migration patterns of Arctic Cisco (Coregonus autumnalis) in the Colville River, Alaska and Mackenzie River, Canada

USGS Publications Warehouse

Zimmerman, Christian E.; Ramey, Andy M.; Turner, S.; Mueter, Franz J.; Murphy, S.; Nielsen, Jennifer L.

2013-01-01

Arctic cisco Coregonus autumnalis have a complex anadromous life history, many aspects of which remain poorly understood. Some life history traits of Arctic cisco from the Colville River, Alaska, and Mackenzie River basin, Canada, were investigated using molecular genetics, harvest data, and otolith microchemistry. The Mackenzie hypothesis, which suggests that Arctic cisco found in Alaskan waters originate from the Mackenzie River system, was tested using 11 microsatellite loci and a single mitochondrial DNA gene. No genetic differentiation was found among sample collections from the Colville River and the Mackenzie River system using molecular markers (P > 0.19 in all comparisons). Model-based clustering methods also supported genetic admixture between sample collections from the Colville River and Mackenzie River basin. A reanalysis of recruitment patterns to Alaska, which included data from recent warm periods and suspected changes in atmospheric circulation patterns, still finds that recruitment is correlated to wind conditions. Otolith microchemistry (Sr/Ca ratios) confirmed repeated, annual movements of Arctic cisco between low-salinity habitats in winter and marine waters in summer.

Ocean plateau-seamount origin of basaltic rocks, Angayucham terrane, central Alaska

USGS Publications Warehouse

Barker, F.; Jones, D.L.; Budahn, J.R.; Coney, P.J.

1988-01-01

The Angayucham terrane of north-central Alaska (immediately S of the Brooks Range) is a large (ca. 500 km E-W), allochthonous complex of Devonian to Lower Jurassic pillow basalt, diabase sills, gabbro plutons, and chert. The mafic rocks are transitional normal-to-enriched, mid-ocean-ridge (MORB) type tholeiites (TiO2 1.2-3.4%, Nb 7-23 ppm, Ta 0.24-1.08 ppm, Zr 69-214 ppm, and light REE's slightly depleted to moderately enriched). Geologic and geochemical constraints indicate that Angayucham terrane is the upper "skin' (ca. 3-4 km thick) of a long-lived (ca. 170-200 ma) oceanic plateau whose basaltic-gabbroic rocks are like those of seamounts of the East Pacific Rise. -Authors

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The Queen Charlotte-Fairweather Fault Zone - Geomorphology of a submarine transform fault, offshore British Columbia and southeastern Alaska

NASA Astrophysics Data System (ADS)

Walton, M. A. L.; Barrie, V.; Greene, H. G.; Brothers, D. S.; Conway, K.; Conrad, J. E.

2017-12-01

The Queen Charlotte-Fairweather (QC-FW) Fault Zone is the Pacific - North America transform plate boundary and is clearly seen for over 900 km on the seabed as a linear and continuous feature from offshore central Haida Gwaii, British Columbia to Icy Point, Alaska. Recently (July - September 2017) collected multibeam bathymetry, seismic-reflection profiles and sediment cores provide evidence for the continuous strike-slip morphology along the continental shelfbreak and upper slope, including a linear fault valley, offset submarine canyons and gullies, and right-step offsets (pull apart basins). South of central Haida Gwaii, the QC-FW is represented by several NW-SE to N-S trending faults to the southern end of the islands. Adjacent to the fault at the southern extreme and offshore Dixon Entrance (Canada/US boundary) are 400 to 600 m high mud volcanos in 1000 to 1600 m water depth that have plumes extending up 700 m into the water column and contain extensive carbonate crusts and chemosynthetic communities within the craters. In addition, gas plumes have been identified that appear to be directly associated with the fault zone. Surficial Quaternary sediments within and adjacent to the central and southern fault date either to the deglaciation of this region of the Pacific north coast (16,000 years BP) or to the last interstadial period ( 40,000 years BP). Sediment accumulation is minimal and the sediments cored are primarily hard-packed dense sands that appear to have been transported along the fault valley. The majority of the right-lateral slip along the entire QC-FW appears to be accommodated by the single fault north of the convergence at its southern most extent.

Chemical and Microphysical Properties of Particles in Aged Forest Fire Plumes From Alaska and Western Canada Observed Over the Northeastern U.S.

NASA Astrophysics Data System (ADS)

Brock, C. A.; Wollny, A. G.; Cooper, O. R.; Fehsenfeld, F. C.; de Gouw, J. A.; Hudson, P. K.; Matthew, B. M.; Middlebrook, A. M.; Murphy, D. M.; Simsons, C.; Stohl, A.; Warneke, C.; Peltier, R.; Sulivan, A.; Weber, R. J.; Wilson, J. C.

2004-12-01

During the Intercontinental Transport and Chemical Transformation - New England Air Quality Study (ITCT-NEAQS 2004) in July and August 2004 several forest fires plumes were observed over the northeastern U.S. and southeastern Canada. Satellite data and trajectory analyses indicate that the plumes originated from forest fires burning in Alaska and western Canada. In-situ measurements of the aged forest fire smoke were made on board the NOAA WP-3D research aircraft during several flights over a period of 2 weeks. Concentrations of volatile organic compounds (VOCs) and the chemical composition of single aerosol particles in air masses containing forest fire smoke show significant differences compared to background air or to pollution from urban and industrial sources and unambiguously identify the smoke plumes. Particle size distributions from 0.004 to 8 um were measured with one second resolution in the aged forest fire smoke. The smoke was characterized by mass-weighted diameters between 0.6 and 1 um--much larger than secondary particles typical of urban and industrial sources. Particle volume concentrations were among the highest seen within the ITCT-NEAQS 2004 project, and regional visibility and air quality were significantly affected by the transported smoke. Quantitative compositional measurements were made of the non-refractory fraction of submicron particles, as well as of submicron inorganic ionic compounds and water soluble organic mass, within the forest fire plumes. The submicron aerosol particles in the biomass plumes were largely carbonaceous with very little sulfate, ammonium, or nitrate. A fraction of this carbonaceous material was soluble in water and likely contained oxygenated organic species.

Pyroclastic deposits of the Mount Edgecumbe volcanic field, southeast Alaska: eruptions of a stratified magma chamber

USGS Publications Warehouse

Riehle, J.R.; Champion, D.E.; Brew, D.A.; Lanphere, M.A.

1992-01-01

The Mount Edgecumbe volcanic field in southeastern Alaska consists of 5-6 km3 (DRE) of postglacial pyroclasts that overlie Pleistocene lavas. All eleven pyroclast vents align with the long axis of the field, implying that the pyroclast magma conduits followed a crustal fissure. Most of these vents had previously erupted lavas that are compositionally similar to the pyroclasts, so a persistent magma system (chamber) had likely evolved by the onset of the pyroclastic eruptions. The pyroclastic sequence was deposited in about a millennium and is remarkable for a wide range of upward-increasing silica contents (51-72% SiO2), which is consistent with rise of coexisting magmas at different rates governed by their viscosity. Basaltic and andesitic lava flows have erupted throughout the lifetime of the field. Rhyolite erupted late; we infer that it formed early but was hindered from rising by its high viscosity. Most of the magmas-and all siliceous ones-erupted from vents on the central fissure. Basalt has not erupted from the center of the field during at least the latter part of its lifetime. Thus the field may illustrate basalt underplating: heat and mass flux are concentrated at the center of a stratified magma chamber in which a cap of siliceous melt blocks the rise of basalt. Major-element, strontium isotope, and mineral compositions of unaltered pyroclasts are broadly similar to those of older lavas of similar SiO2 content. Slightly fewer phenocrysts, inherited grains, and trace amphibole in pyroclastic magmas may be due simply to faster rise and less undercooling and degassing before eruption relative to the lavas. Dacite occurs only in the youngest deposits; the magma formed by mixing of andesitic and rhyolitic magmas erupted shortly before by the dacitic vents. ?? 1992.

The Queen Charlotte-Fairweather Fault Zone - Geomorphology of a submarine transform fault, offshore British Columbia and southeastern Alaska

NASA Astrophysics Data System (ADS)

Walton, M. A. L.; Barrie, V.; Greene, H. G.; Brothers, D. S.; Conway, K.; Conrad, J. E.

2016-12-01

The Queen Charlotte-Fairweather (QC-FW) Fault Zone is the Pacific - North America transform plate boundary and is clearly seen for over 900 km on the seabed as a linear and continuous feature from offshore central Haida Gwaii, British Columbia to Icy Point, Alaska. Recently (July - September 2017) collected multibeam bathymetry, seismic-reflection profiles and sediment cores provide evidence for the continuous strike-slip morphology along the continental shelfbreak and upper slope, including a linear fault valley, offset submarine canyons and gullies, and right-step offsets (pull apart basins). South of central Haida Gwaii, the QC-FW is represented by several NW-SE to N-S trending faults to the southern end of the islands. Adjacent to the fault at the southern extreme and offshore Dixon Entrance (Canada/US boundary) are 400 to 600 m high mud volcanos in 1000 to 1600 m water depth that have plumes extending up 700 m into the water column and contain extensive carbonate crusts and chemosynthetic communities within the craters. In addition, gas plumes have been identified that appear to be directly associated with the fault zone. Surficial Quaternary sediments within and adjacent to the central and southern fault date either to the deglaciation of this region of the Pacific north coast (16,000 years BP) or to the last interstadial period ( 40,000 years BP). Sediment accumulation is minimal and the sediments cored are primarily hard-packed dense sands that appear to have been transported along the fault valley. The majority of the right-lateral slip along the entire QC-FW appears to be accommodated by the single fault north of the convergence at its southern most extent.

Soft-sediment deformation produced by tides in a meizoseismic area, Turnagain Arm, Alaska

USGS Publications Warehouse

Greb, S.F.; Archer, A.W.

2007-01-01

Turnagain Arm is a semidiurnal hypertidal estuary in southeastern Alaska with a recorded tidal range of 9 m. Contorted bedding and flow rolls preserved in tidal sediments within the estuary have previously been interpreted as resulting from the Mw 9.2 Great Alaskan earthquake of 1964. Horizons of flow rolls between undeformed beds in sediments and rock strata have been used to infer ancient earthquakes in other areas. Although many types of soft-sediment deformation structures can be formed by earthquakes, observations of sedimentation on tidal flats in the inner parts of Turnagain Arm in the summers of 2003 and 2004 show that a wide range of soft-sediment deformation structures, similar to those inferred to have been formed by earthquakes, can form in macrotidal estuaries in the absence of seismic shock. During sedimentation rate measurements in 2004, soft-sediment deformation structures were recorded that formed during one day's tide, either in response to overpressurization of tidal flats during rapid tidal drawdown or by shear stress exerted on the bed by the passage of a 1.8 m tidal bore. Structures consisted of How rolls, dish structures, flames, and small dewatering pipes in a bed 17 cm thick. In the future, if the flow rolls in Turnagain Arm were found in isolated outcrops across an area 11 km in length, in an estuary known to have been influenced by large-magnitude earthquakes, would they be interpreted as seismites? These examples show that caution is needed when using horizons of flow rolls to infer paleoseismicity in estuarine deposits because many of the mechanisms (tidal flux, tidal bores, slumping, flooding) that can cause deformation in rapidly deposited, unconsolidated silts and sands, are orders of magnitude more common than great earthquakes. ?? 2007 The Geological Society of America.

Identification of Cylindrocarpon species associated with Black-Foot of grapevine in Northeastern United States and Southeastern Canada

USDA-ARS?s Scientific Manuscript database

Black-foot disease of grapevine is caused by a complex of soilborne fungi. The most common and virulent species, which are found across all major grape-growing regions of the world, are Cylindrocarpon liriodendri (Cl. liriodendri) and Cl. macrodidymum (teleomorph = Neonectria). Other species with a ...

Women Mentoring in the Academe: A Faculty Cross-Racial and Cross-Cultural Experience

ERIC Educational Resources Information Center

Guramatunhu-Mudiwa, Precious; Angel, Roma B.

2017-01-01

Two women faculty members, one White from the southeastern United States and one Black African from Zimbabwe, purposefully explored their informal mentoring relationship with the goal of illuminating the complexities associated with their cross-racial, cross-cultural experience. Concentrating on their four-year mentor-mentee academic relationship…

Landscape effects on reproduction of Euschistus servus (Hemiptera: Pentatomidae), a mobile, polyphagous, multivoltine arthropod herbivore

USDA-ARS?s Scientific Manuscript database

The brown stink bug is an economic pest of many crops in the southeastern US. In this study we characterized the complexity, land-use intensity and distances between differently-cropped fields on landscapes in two regions of southern Georgia, USA. We estimated brown stink bug reproduction, predator ...

Analyzing the complexity of cone production in longleaf pine by multiscale entropy

Treesearch

Xiongwen Chen; Qinfeng Guo; Dale G. Brockway

2016-01-01

The longleaf pine (Pinus palustris Mill.) forests are important ecosystems in the southeastern USA because of their ecological and economic value. Since European settlement, longleaf pine ecosystems have dramatically declined in extent, to the degree that they are now listed as endangered ecosystems. Its sporadic seed production, which...

Direct effects of fire on endangered Mount Graham red squirrels

Treesearch

John L. Koprowski; Katherine M. Leonard; Claire A. Zugmeyer; Julia L. Jolley

2006-01-01

Direct mortality of forest wildlife due to fire is rarely documented. In June and July 2004, the Nuttall Complex Fire burned 11,898 ha in the Pinaleno Mountains, southeastern Arizona. Portions of these mountains serve as the only habitat of endangered Mount Graham red squirrels (Tamiasciurus hudsonicus grahamensis). Survival of radio-collared red...

Genetic Diversity of Anopheles triannulatus s.l. (Diptera: Culicidae) from Northwestern and Southeastern Colombia

PubMed Central

Rosero, Doris A.; Jaramillo, Luz M.; Gutiérrez, Lina A.; Conn, Jan E.; Correa, Margarita M.

2012-01-01

Anopheles triannulatus s.l. is a species complex, however in Colombia its taxonomic status is unclear. This study was conducted to understand the level of genetic differentiation or population structure of specimens of An. triannulatus s.l. from northwestern and southeastern Colombia. Cytochrome oxidase subunit I (COI) and internal transcribed spacer (ITS2) sequence analyses suggested high genetic differentiation between the NW and SE populations. A TCS network and Bayesian inference analysis based on 814 bp of COI showed two main groups: group I included samples from the NW and group II samples from the SE. Two main ITS2-polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) patterns were found. Pattern I is present in both the NW and SE, and pattern II is found in the SE specimens. To further elucidate the taxonomic status of An. triannulatus s.l. in Colombia and how these COI lineages are related to the Triannulatus Complex species, the evaluation of immature stages, male genitalia, and additional mitochondrial and nuclear markers will be needed. PMID:22949519

Genetic diversity of Anopheles triannulatus s.l. (Diptera: Culicidae) from northwestern and southeastern Colombia.

PubMed

Rosero, Doris A; Jaramillo, Luz M; Gutiérrez, Lina A; Conn, Jan E; Correa, Margarita M

2012-11-01

Anopheles triannulatus s.l. is a species complex, however in Colombia its taxonomic status is unclear. This study was conducted to understand the level of genetic differentiation or population structure of specimens of An. triannulatus s.l. from northwestern and southeastern Colombia. Cytochrome oxidase subunit I (COI) and internal transcribed spacer (ITS2) sequence analyses suggested high genetic differentiation between the NW and SE populations. A TCS network and Bayesian inference analysis based on 814 bp of COI showed two main groups: group I included samples from the NW and group II samples from the SE. Two main ITS2-polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) patterns were found. Pattern I is present in both the NW and SE, and pattern II is found in the SE specimens. To further elucidate the taxonomic status of An. triannulatus s.l. in Colombia and how these COI lineages are related to the Triannulatus Complex species, the evaluation of immature stages, male genitalia, and additional mitochondrial and nuclear markers will be needed.

Acid rain, air pollution, and tree growth in southeastern New York

USGS Publications Warehouse

Puckett, L.J.

1982-01-01

Whether dendroecological analyses could be used to detect changes in the relationship of tree growth to climate that might have resulted from chronic exposure to components of the acid rain-air pollution complex was determined. Tree-ring indices of white pine (Pinus strobus L.), eastern hemlock (Tsuga canadensis (L.) Cart.), pitch pine (Pinus rigida Mill.), and chestnut oak (Quercus prinus L.) were regressed against orthogonally transformed values of temperature and precipitation in order to derive a response-function relationship. Results of the regression analyses for three time periods, 1901–1920, 1926–1945, and 1954–1973 suggest that the relationship of tree growth to climate has been altered. Statistical tests of the temperature and precipitation data suggest that this change was nonclimatic. Temporally, the shift in growth response appears to correspond with the suspected increase in acid rain and air pollution in the Shawangunk Mountain area of southeastern New York in the early 1950's. This change could be the result of physiological stress induced by components of the acid rain-air pollution complex, causing climatic conditions to be more limiting to tree growth.

Distribution of near-surface permafrost in Alaska: estimates of present and future conditions

USGS Publications Warehouse

Pastick, Neal J.; Jorgenson, M. Torre; Wylie, Bruce K.; Nield, Shawn J.; Johnson, Kristofer D.; Finley, Andrew O.

2015-01-01

High-latitude regions are experiencing rapid and extensive changes in ecosystem composition and function as the result of increases in average air temperature. Increasing air temperatures have led to widespread thawing and degradation of permafrost, which in turn has affected ecosystems, socioeconomics, and the carbon cycle of high latitudes. Here we overcome complex interactions among surface and subsurface conditions to map nearsurface permafrost through decision and regression tree approaches that statistically and spatially extend field observations using remotely sensed imagery, climatic data, and thematic maps of a wide range of surface and subsurface biophysical characteristics. The data fusion approach generated medium-resolution (30-m pixels) maps of near-surface (within 1 m) permafrost, active-layer thickness, and associated uncertainty estimates throughout mainland Alaska. Our calibrated models (overall test accuracy of ~85%) were used to quantify changes in permafrost distribution under varying future climate scenarios assuming no other changes in biophysical factors. Models indicate that near-surface permafrost underlies 38% of mainland Alaska and that near-surface permafrost will disappear on 16 to 24% of the landscape by the end of the 21st Century. Simulations suggest that near-surface permafrost degradation is more probable in central regions of Alaska than more northerly regions. Taken together, these results have obvious implications for potential remobilization of frozen soil carbon pools under warmer temperatures. Additionally, warmer and drier conditions may increase fire activity and severity, which may exacerbate rates of permafrost thaw and carbon remobilization relative to climate alone. The mapping of permafrost distribution across Alaska is important for land-use planning, environmental assessments, and a wide-array of geophysical studies.

Animistic pragmatism and native ways of knowing: adaptive strategies for overcoming the struggle for food in the sub-Arctic

PubMed Central

Anthony, Raymond

2013-01-01

Background Subsistence norms are part of the “ecosophy” or ecological philosophy of Alaska Native Peoples in the sub-Arctic, such as the Inupiat of Seward Peninsula. This kind of animistic pragmatism is a special source of practical wisdom that spans over thousands of years and which has been instrumental in the Iñupiat's struggle to survive and thrive in harsh and evolving environments. Objective I hope to show how narrative in relationship to the “ecosophy” of Alaska Native peoples can help to promote a more ecological orientation to address food insecurity in rural communities in Alaska. Alaska Native ecosophy recommends central values and virtues necessary to help address concerns in Alaska's rural communities. Design Here, I will tease out the nature of this “ecosophy” in terms of animistic pragmatism and then show why this form of pragmatism can be instrumental for problematizing multi-scalar, intergenerational, uncertain and complex environmental challenges like food security. Results Native elders have been the embodiment of trans-generational distributed cognition,1 for example, collective memory, norms, information, knowledge, technical skills and experimental adaptive strategies. They are human “supercomputers,” historical epistemologists and moral philosophers of a sort who use narrative, a form of moral testimony, to help their communities face challenges and seize opportunities in the wake of an ever-changing landscape. Conclusions The “ecosophy” of the Iñupiat of Seward Peninsula offers examples of “focal practices”, which are essential for environmental education. These focal practices instil key virtues, namely humility, gratitude, self-reliance, attentiveness, responsibility and responsiveness, that are necessary for subsistence living. PMID:23986900

Publications - PDF 96-17 | Alaska Division of Geological & Geophysical

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Publications - MP 156 | Alaska Division of Geological & Geophysical Surveys

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Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska /29446 Publication Products Report Report Information mp156.pdf (126.0 K) Digital Geospatial Data Digital State of Alaska © 2010 Webmaster State of Alaska myAlaska My Government Resident Business in Alaska

Publications - RDF 2015-16 | Alaska Division of Geological & Geophysical

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rocks collected in 2015 in the Wrangellia mineral assessment area, Alaska: Alaska Division of Geological Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

Publications - RDF 2008-2 v. 1.0.1 | Alaska Division of Geological &

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Publications - RDF 2015-9 | Alaska Division of Geological & Geophysical

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samples from the Zane Hills, Hughes and Shungnak quadrangles, Alaska: Alaska Division of Geological & Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

Purchasing, Division of General Services, Department of Administration,

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Mitochondrial DNA diversity in two ethnic groups in southeastern Kenya: perspectives from the northeastern periphery of the Bantu expansion

PubMed Central

Batai, Ken; Babrowski, Kara B.; Arroyo, Juan Pablo; Kusimba, Chapurukha M.; Williams, Sloan R.

2013-01-01

The Bantu languages are widely distributed throughout sub-Saharan Africa. Genetic research supports linguists and historians who argue that migration played an important role in the spread of this language family, but the genetic data also indicates a more complex process involving substantial gene flow with resident populations. In order to understand the Bantu expansion process in east Africa, mtDNA hypervariable region I variation in 352 individuals from the Taita and Mijikenda ethnic groups was analyzed, and we evaluated the interactions that took place between the Bantu- and non-Bantu-speaking populations in east Africa. The Taita and Mijikenda are Bantu-speaking agropastoralists from southeastern Kenya, at least some of whose ancestors probably migrated into the area as part of Bantu migrations that began around 3,000 BCE. Our analyses indicate that they show some distinctive differences that reflect their unique cultural histories. The Taita are genetically more diverse than the Mijikenda with larger estimates of genetic diversity. The Taita cluster with other east African groups, having high frequencies of haplogroups from that region, while the Mijikenda have high frequencies of central African haplogroups and cluster more closely with central African Bantu-speaking groups. The non-Bantu speakers who lived in southeastern Kenya before Bantu speaking groups arrived were at least partially incorporated into what are now Bantu-speaking Taita groups. In contrast, gene flow from non-Bantu speakers into the Mijikenda was more limited. These results suggest a more complex demographic history where the nature of Bantu and non-Bantu interactions varied throughout the area. PMID:23382080

Alaska Public Offices Commission, Department of Administration, State of

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Genetic variability of Echinococcus granulosus complex in various geographical populations of Iran inferred by mitochondrial DNA sequences.

PubMed

Spotin, Adel; Mahami-Oskouei, Mahmoud; Harandi, Majid Fasihi; Baratchian, Mehdi; Bordbar, Ali; Ahmadpour, Ehsan; Ebrahimi, Sahar

2017-01-01

To investigate the genetic variability and population structure of Echinococcus granulosus complex, 79 isolates were sequenced from different host species covering human, dog, camel, goat, sheep and cattle as of various geographical sub-populations of Iran (Northwestern, Northern, and Southeastern). In addition, 36 sequences of other geographical populations (Western, Southeastern and Central Iran), were directly retrieved from GenBank database for the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. The confirmed isolates were grouped as G1 genotype (n=92), G6 genotype (n=14), G3 genotype (n=8) and G2 genotype (n=1). 50 unique haplotypes were identified based on the analyzed sequences of cox1. A parsimonious network of the sequence haplotypes displayed star-like features in the overall population containing IR23 (22: 19.1%) as the most common haplotype. According to the analysis of molecular variance (AMOVA) test, the high value of haplotype diversity of E. granulosus complex was shown the total genetic variability within populations while nucleotide diversity was low in all populations. Neutrality indices of the cox1 (Tajima's D and Fu's Fs tests) were shown negative values in Western-Northwestern, Northern and Southeastern populations which indicating significant divergence from neutrality and positive but not significant in Central isolates. A pairwise fixation index (Fst) as a degree of gene flow was generally low value for all populations (0.00647-0.15198). The statistically Fst values indicate that Echinococcus sensu stricto (genotype G1-G3) populations are not genetically well differentiated in various geographical regions of Iran. To appraise the hypothetical evolutionary scenario, further study is needed to analyze concatenated mitogenomes and as well a panel of single locus nuclear markers should be considered in wider areas of Iran and neighboring countries. Copyright © 2016 Elsevier B.V. All rights reserved.

Publications - STATEMAP Project | Alaska Division of Geological &

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., 2008, Surficial-geologic map of the Salcha River-Pogo area, Big Delta Quadrangle, Alaska: Alaska , Engineering - geologic map, Alaska Highway corridor, Delta Junction to Dot Lake, Alaska: Alaska Division of geologic map of the Salcha River-Pogo area, Big Delta Quadrangle, Alaska: Alaska Division of Geological

Geochronologic and paleomagnetic evidence defining the relationship between the Miocene Hiko and Racer Canyon tuffs, eccentric outflow lobes from the Caliente caldera complex, southeastern Great Basin, USA

USGS Publications Warehouse

Gromme, S.; Deino, A.M.; Best, M.G.; Hudson, M.R.

1997-01-01

Outflow sheets of the Hiko tuff and the Racer Canyon tuff, which together extend over approximately 16000 km2 around the Caliente caldera complex in southeastern Nevada, have long been considered to be products of simultaneous or near-simultaneous eruptions from inset calderas in the west and east ends, respectively, of the caldera complex. New high-precision 40Ar/39Ar geochronology and paleomagnetic data demonstrate that emplacement of the uppermost part of the Racer Canyon tuff at 18.33??0.03 Ma was nearly synchronous with emplacement of the single outflow cooling unit of the much larger overlying Hiko tuff at 18.32??0.04 Ma. Based on comparison with the geomagnetic polarity time scale derived from the sea-floor spreading record, we conclude that emplacement of the first of several outflow cooling units of the Racer Canyon tuff commenced approximately 0.5 m.y. earlier. Only one paleomagnetic polarity is found in the Hiko tuff, but at least two paleomagnetic reversals have been found in the Racer Canyon tuff. The two formations overlap in only one place, at and near Panaca Summit northeast of the center of the Caliente caldera complex; here the Hiko tuff is stratigraphically above the Racer Canyon tuff. This study demonstrates the power of combining 40Ar/39Ar and paleomagnetic data in conjunction with phenocryst compositional modes to resolve problematic stratigraphic correlations in complex ash-flow sequences where use of one method alone might not eliminate ambiguities.

Publications - RDF 2015-7 | Alaska Division of Geological & Geophysical

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, Geochemical reanalysis of historical U.S. Geological Survey sediment samples from the northeastern Alaska Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

Publications - MP 142 | Alaska Division of Geological & Geophysical Surveys

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Publications - SR 70 | Alaska Division of Geological & Geophysical Surveys

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Presentations - Twelker, Evan and Lande, Lauren, 2015 | Alaska Division of

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Publications - MP 38 | Alaska Division of Geological & Geophysical Surveys

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Publications - SR 45 | Alaska Division of Geological & Geophysical Surveys

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Publications - MP 43 | Alaska Division of Geological & Geophysical Surveys

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Publications - MP 149 | Alaska Division of Geological & Geophysical Surveys

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Presentations - Wypych, Alicja and others, 2015 | Alaska Division of

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Facts About Alaska, Alaska Kids' Corner, State of Alaska

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Le volcanisme cambrien du Maroc central : implications géodynamiquesThe Central Morocco Cambrian volcanism: geodynamic implications

NASA Astrophysics Data System (ADS)

Ouali, Houssa; Briand, Bernard; Bouchardon, Jean-Luc; Capiez, Paul

2003-05-01

In southeastern Central Morocco, the Bou-Acila volcanic complex is considered of Cambrian age. In spite of low-grade metamorphic effect, initial volcanic texture and mineralogy can be recognized and volcanic rocks are dominated by dolerites and porphyric dolerites. The initial mineralogy is composed of plagioclases, pyroxenes and dark minerals. A secondary mineral assemblage is composed of albite, epidote, chlorite and calcite. According to their immobile elements compositions, the southeastern central Morocco metavolcanites are of within-plate continental tholeiites. This volcanism and those recognized in many other areas in Morocco confirm a Cambrian extensive episode within the Gondwana supercontinent. To cite this article: H. Ouali et al., C. R. Geoscience 335 (2003).To cite this article: H. Ouali et al., C. R. Geoscience 335 (2003).

Presentations - Twelker, Evan and others, 2014 | Alaska Division of

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magmatic Ni-Cu-Co-PGE system in the Talkeetna Mountains, central Alaska (poster): Society of Economic Geological & Geophysical Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of

Publications - GMC 193 | Alaska Division of Geological & Geophysical

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Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical materials: Alaska State F #1, washed cuttings (13,980' - 13,990'); West Mikkelsen State #1, Canning River

Seasonal cross-shelf distribution of major zooplankton taxa on the northern Gulf of Alaska shelf relative to water mass properties, species depth preferences and vertical migration behavior

NASA Astrophysics Data System (ADS)

Coyle, Kenneth O.; Pinchuk, Alexei I.

2005-01-01

The cross-shelf distribution of major zooplankton species was examined on the northern Gulf of Alaska (GOA) shelf during the production season for four years, between October 1997 and October 2001. The zooplankton community on the northern GOA shelf consisted of oceanic and neritic species of the North Pacific subarctic species complex. Cross-shelf distribution of the major zooplankton species was influenced by their depth preferences, vertical migration behavior, salinity-temperature preferences, and by cross-shelf water-mass distribution and movement. The neritic community, dominated by Pseudocalanus spp., Metridia pacifica and Calanus marshallae, had highest abundances on the inner shelf, in the Alaska Coastal Current, and in the adjacent fjords in late spring and early summer. The oceanic community, which contained primarily Neocalanus cristatus and Eucalanus bungii, was observed in the Alaskan Stream and adjacent waters near the shelf break. A mid-shelf transition zone contained a mixture of oceanic and neritic species. Prince William Sound (PWS) contained a unique species complex of large mesopelagic copepods, amphipods and shrimp. Neocalanus flemingeri and Oithona similis were abundant in all four regions during spring and early summer. The transition zone commonly crossed much of the shelf between the shelf break and the ACC, but satellite images and CTD data indicate that occasionally a narrow shelf-break front can form, in which case distinct zooplankton species groups are observed on either side of the front. Satellite data also revealed numerous large and small eddies, which probably contribute to cross-shelf mixing in the transition zone.

Geospatial analysis of lake and landscape interactions within the Toolik Lake region, North Slope of Alaska

NASA Astrophysics Data System (ADS)

Pathak, Prasad A.

The Arctic region of Alaska is experiencing severe impacts of climate change. The Arctic lakes ecosystems are bound to undergo alterations in its trophic structure and other chemical properties. However, landscape factors controlling the lake influxes were not studied till date. This research has examined the currently existing lake landscape interactions using Remote Sensing and GIS technology. The statistical modeling was carried out using Regression and CART methods. Remote sensing data was applied to derive the required landscape indices. Remote sensing in the Arctic Alaska faces many challenges including persistent cloud cover, low sun angle and limited snow free period. Tundra vegetation types are interspersed and intricate to classify unlike managed forest stands. Therefore, historical studies have remained underachieved with respect thematic accuracies. However, looking at vegetation communities at watershed level and the implementation of expert classification system achieved the accuracies up to 90%. The research has highlighted the probable role of interactions between vegetation root zones, nutrient availability within active zone, as well as importance of permafrost thawing. Multiple regression analyses and Classification Trees were developed to understand relationships between landscape factors with various chemical parameters as well as chlorophyll readings. Spatial properties of Shrubs and Riparian complexes such as complexity of individual patches at watershed level and within proximity of water channels were influential on Chlorophyll production of lakes. Till-age had significant impact on Total Nitrogen contents. Moreover, relatively young tills exhibited significantly positive correlation with concentration of various ions and conductivity of lakes. Similarly, density of patches of Heath complexes was found to be important with respect to Total Phosphorus contents in lakes. All the regression models developed in this study were significant at 95% confidence level. However, the classification trees could not achieve high predictabilities due to limited number of lakes sampled. Keywords: Landscape factors, Lake primary productivity, Arctic, Climate change, Regression, CART

Provenance of Marine Sediment in the Gulf of Alaska, IODP Expedition 341: Links Between Sediment Derivation, Glacial Systems, and Exhumation of the Coastal Mountain Belts

NASA Astrophysics Data System (ADS)

Allen, W. K.; Dunn, C. A.; Enkelmann, E.; Ridgway, K.; Colliver, L.

2015-12-01

Provenance analysis of Neogene sand and diamict beds from marine boreholes drilled by the IODP Expedition 341 provides a marine sedimentary record of the interactions between tectonics, climate and sediment deposition along a glaciated convergent margin. The 341 boreholes represent a cross-margin transect that sampled the continental shelf, slope, and deep sea Surveyor Fan of the Gulf of Alaska. Our dataset currently consists of ~ 650 detrital zircons selected for double dating method utilizing both detrital zircon fission track (FT) and U-Pb analysis from sand and diamict beds, as well as zircon U-Pb geochronology and apatite FT from igneous and gneissic clasts. Detrital zircon U-Pb geochronology of sand records dominant peak ages of 53, 62, 70, and 98 Ma with minor populations of 117, 154, and 170 Ma. Most of these ages can be correlated to primary igneous sources in the Coast Plutonic Complex, the Chugach Metamorphic Complex, the plutonic rocks of Wrangellia, and the Sanak-Baranoff plutonic belt. All samples analyzed to date, covering a 10 Myr range, share nearly identical detrital zircon populations suggesting similar primary sediment sources and reworking of sediment in thrust belts and accretionary prisms along this convergent margin. Plutonic and gneissic clasts collected from the boreholes on the shelf have already been double dated. These clasts have general U-Pb zircon crystallization ages of 52-54 Ma and apatite fission track cooling ages of 10-12 Ma. These results, along with previous published studies, indicate that these clasts were derived from the Chugach Metamorphic Complex and were eroded and transported by the Bagley Ice Field and Bering Glacier. Future results using this approach should allow us to pinpoint which parts of the exhumed onshore ranges and which glacial systems provided sediment to marine environments in the Gulf of Alaska.

Structural correction of paleomagnetic vectors dispersed about two fold axes and application to the Duke Island (Alaska) ultramafic complex

NASA Astrophysics Data System (ADS)

Bogue, Scott W.; Grommé, C. Sherman

2004-11-01

A new analysis of paleomagnetic data from the mid-Cretaceous (˜110 Ma) ultramafic complex at Duke Island (southeast Alaska) supports large poleward transport of the Insular superterrane relative to North America consistent with the Baja British Columbia hypothesis. Previous paleomagnetic work has shown that the characteristic remanence of the ultramafic complex predates kilometer-scale deformation of the very well developed cumulate layering but that the layering was not horizontal everywhere before the folding. It is possible, however, to estimate paleohorizontal for the Duke Island ultramafic complex because the postremanence deformation of the intrusion occurred about two well-defined and spatially separate fold axes. In such a case the tectonically rotated paleomagnetic directions should be distributed along small circles centered on each of the two fold axes. The ancient field direction will lie on both small circles and therefore will be identifiable as one of their two intersection points. Interpreted this way, the tectonically rotated remanence of the Duke Island ultramafic complex defines a mid-Cretaceous (i.e., ancient) field direction that is within 2° of the paleomagnetic direction found by assuming the cumulate layering was initially horizontal (despite the paleomagnetic evidence to the contrary) and performing the standard structure correction. The inferred mid-Cretaceous paleolatitude of Duke Island is 21.2° (2350 km) anomalous with respect to cratonic North America. This result is concordant with southerly paleolatitudes determined by many other workers from bedded rocks of terranes farther inboard in the Insular and Intermontane superterranes.

Measurements of NO(x) and NO(y) concentrations and fluxes over Arctic tundra

NASA Technical Reports Server (NTRS)

Bakwin, Peter S.; Wofsy, Steven C.; Fan, Song-Miao; Fitzjarrald, David R.

1992-01-01

Measurements of the atmospheric concentrations of NO, NO2, total NO(y), and O3 were made during the NASA Arctic Boundary Layer Expedition (ABLE 3A) at a remote location in a tundra bog ecosystem in southeastern Alaska during the growing season (July-August 1988). Concentrations of NO(x) and NO(y) were found to be very low compared to other remote continental sites, indicating that anthropogenic influences were small at this site during this time of year. The NO(y) emission rate from the soil were 0.13 +/- 0.05 x 10 exp 9 molecules/sq cm/s. Direct measurements of the flux of total NO(y) were made for the first time, indicating downward flux of NO(y) at all times of day, with maximum deposition of 2.5 +/- 0.9 x 10 exp 9 molecules/sq cm/s in the afternoon. Deposition of HNO3 appears to dominate the atmosphere/surface exchange of NO(y). The mean dry deposition rate of NO(y) to the tundra was 1.8 +/- 1.0 x 10 exp 9 molecules/sq cm/s.

Publications - GMC 53C | Alaska Division of Geological & Geophysical

Science.gov Websites

Alaska's Mineral Industry Reports AKGeology.info Rare Earth Elements WebGeochem Engineering Geology Alaska Paleozoic through Tertiary sandstones, North Slope, Alaska Authors: Alaska Research Associates Publication through Tertiary sandstones, North Slope, Alaska: Alaska Division of Geological & Geophysical Surveys

Comparison of the Effects of Episodic Organizers and Traditional Notetaking on Story Recall. Final Report.

ERIC Educational Resources Information Center

Denner, Peter R.

Since the precise nature of the effects of notetaking encoding has not been clearly specified, a study involving 111 suburban seventh graders (southeastern Idaho) explored the differential effects of traditional notetaking and of episodic organizers (a type of semantic web or map) on the encoding of complex narrative passages. Subjects were…

Evaluating hydroperiod response in restored Carolina Bay Westlands using soil physicochemical properties

Treesearch

Christopher D. Barton; Danielle M. Andrews; Randall K. Kolka

2008-01-01

Carolina bays are shallow depression wetlands found in the southeastern United States that have been severely altered by human activity. The need to restore these complex and diverse systems is well established, but our limited understanding of wetland hydrologic processes in these systems hinders our ability to assess the effectiveness of bay restoration efforts....

Mineral Nutrition, Resin Flow and Phloem Phystochemistry in Loblolly Pine

Treesearch

Jefferey M. Warren; H. Lee Allen; Fitzgerald L. Booker

1999-01-01

Southern pine beetles and associated pathogenic fungi represent the largest biotic threat to pine forests in the southeastern USA. The two primary defensive mechanisms of the tree to the beetle-fungal complex are the primary oleoresin flow and the concentrations of preformed and induced secondary compounds. We compared oleoresin flow and concentrations of phloem...

Cultural Context of School Communities in Rural Hawaii to Inform Youth Violence Prevention

ERIC Educational Resources Information Center

Affonso, Dyanne D.; Mayberry, Linda; Shibuya, June Y.; Archambeau, Olga G.; Correa, Mary; Deliramich, Aimee N.; Frueh, B. Christopher

2010-01-01

Background: Escalation of youth violence within a large geographic school-complex area in southeastern rural Hawaii became a major problem in 2006. How cultural forces impact the problem was an impetus to examine youth violence from perspectives of adults and children in rural communities. Gathering these data was an essential first step toward…

The Studio Experience at the University of Georgia: An Example of Constructionist Learning for Adults

ERIC Educational Resources Information Center

Clinton, Gregory; Rieber, Lloyd P.

2010-01-01

The Studio curriculum in the Learning, Design, and Technology (formerly Instructional Technology) program at a large research-extensive university in the southeastern U.S. represents a deliberate application of contemporary theory of how adults learn complex information in ill-structured domains. The Studio curriculum, part of a graduate program…

Milwaukee Area Technical College's Fiscal Condition: Growing Demand, Shrinking Resources. An Independent Third-Party Analysis

ERIC Educational Resources Information Center

Day, Douglass; Allen, Vanessa; Henken, Rob

2010-01-01

The Milwaukee Area Technical College (MATC) is one of the largest local taxpayer-funded entities in southeastern Wisconsin, ranking fourth in assets and budget behind Milwaukee County, the Milwaukee Public Schools, and the City of Milwaukee. The college's fiscal operations are complex and draw on multiple revenue sources, including nearly $150…

Laurel wilt in natural and agricultural ecosystems: Understanding the drivers and scales of complex pathosystems

Treesearch

Randy Ploetz; Paul Kendra; Robin Choudhury; Jeffrey Rollins; Alina Campbell; Karen Garrett; Marc Hughes; Tyler Dreaden

2017-01-01

Laurel wilt kills members of the Lauraceae plant family in the southeastern United States. It is caused by Raffaelea lauricola T.C. Harr., Fraedrich and Aghayeva, a nutritional fungal symbiont of an invasive Asian ambrosia beetle, Xyleborus glabratus Eichhoff, which was detected in Port Wentworth, Georgia, in 2002. The beetle...

A Comparison of Simulated and Field-Derived Leaf Area Index (LAI) and Canopy Height Values from Four Forest Complexes in the Southeastern USA

EPA Science Inventory

Vegetative leaf area is a critical input to models that simulate human and ecosystem exposure to atmospheric pollutants. Leaf area index (LAI) can be measured in the field or numerically simulated, but all contain some inherent uncertainty that is passed to the exposure assessmen...

76 FR 62087 - Draft Conservation Plan and Draft Environmental Assessment; Dunes Sagebrush Lizard, Texas

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-06

... known as the sand dune lizard, and the lesser prairie-chicken, among the Service, the Bureau of Land... southeastern New Mexico and west Texas. The species only occurs in sand dune complexes associated with shinnery... direct, indirect, and cumulative impacts of the TCP on the quality of the human environment and other...

Phylogeography and conservation genetics of the Caribbean Zamia clade: an integrated systematic approach with SSRs and single copy nuclear genes

USDA-ARS?s Scientific Manuscript database

The Zamia pumila L. complex (Cycadales: Zamiaceae) is a monophyletic, diploid (2n = 16) and distinctive assemblage of cycad populations restricted to the West Indies and southeastern U. S. that has been treated as comprising one to nine species. Our research project seeks to simultaneously investi...

Alaska Seismic Hazards Safety Commission

Science.gov Websites

State Employees ASHSC State of Alaska search Alaska Seismic Hazards Safety Commission View of Anchorage and Commissions Alaska Seismic Hazards Safety Commission (ASHSC) main contant Alaska Seismic Hazards Safety Commission logo Alaska Seismic Hazards Safety Commission (ASHSC) - Mission The Alaska Seismic

Publications - MP 150 | Alaska Division of Geological & Geophysical Surveys

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Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska larger work. Please see DDS 3 for more information. Digital Geospatial Data Digital Geospatial Data Business in Alaska Visiting Alaska State Employees

78 FR 53137 - Flint Hills Resources Alaska, LLC, BP Pipelines (Alaska) Inc., ConocoPhillips Transportation...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-28

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket Nos. OR13-31-000] Flint Hills Resources Alaska, LLC, BP Pipelines (Alaska) Inc., ConocoPhillips Transportation Alaska, Inc., ExxonMobil... (Alaska) Inc., ConocoPhillips Transportation Alaska, Inc., and ExxonMobil Pipeline Company (collectively...

Publications - RI 2009-3 | Alaska Division of Geological & Geophysical

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Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska , northeastern Brooks Range, Alaska, scale 1:63,360 (129.0 M) Digital Geospatial Data Digital Geospatial Data Resident Business in Alaska Visiting Alaska State Employees

Publications - RI 2011-4 | Alaska Division of Geological & Geophysical

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Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska district, Circle Quadrangle, Alaska, scale 1:50,000 (16.0 M) Digital Geospatial Data Digital Geospatial Business in Alaska Visiting Alaska State Employees

Triggered tremor sweet spots in Alaska

NASA Astrophysics Data System (ADS)

Gomberg, Joan; Prejean, Stephanie

2013-12-01

To better understand what controls fault slip along plate boundaries, we have exploited the abundance of seismic and geodetic data available from the richly varied tectonic environments composing Alaska. A search for tremor triggered by 11 large earthquakes throughout all of seismically monitored Alaska reveals two tremor "sweet spots"—regions where large-amplitude seismic waves repeatedly triggered tremor between 2006 and 2012. The two sweet spots locate in very different tectonic environments—one just trenchward and between the Aleutian islands of Unalaska and Akutan and the other in central mainland Alaska. The Unalaska/Akutan spot corroborates previous evidence that the region is ripe for tremor, perhaps because it is located where plate-interface frictional properties transition between stick-slip and stably sliding in both the dip direction and laterally. The mainland sweet spot coincides with a region of complex and uncertain plate interactions, and where no slow slip events or major crustal faults have been noted previously. Analyses showed that larger triggering wave amplitudes, and perhaps lower frequencies (< 0.03 Hz), may enhance the probability of triggering tremor. However, neither the maximum amplitude in the time domain or in a particular frequency band, nor the geometric relationship of the wavefield to the tremor source faults alone ensures a high probability of triggering. Triggered tremor at the two sweet spots also does not occur during slow slip events visually detectable in GPS data, although slow slip below the detection threshold may have facilitated tremor triggering.

Genetic stock identification of immature chum salmon ( Oncorhynchus keta) in the western Bering Sea, 2004

NASA Astrophysics Data System (ADS)

Kang, Minho; Kim, Suam; Low, Loh-Lee

2016-03-01

Genetic stock identification studies have been widely applied to Pacific salmon species to estimate stock composition of complex mixed-stock fisheries. In a September-October 2004 survey, 739 chum salmon ( Oncorhynchus keta) specimens were collected from 23 stations in the western Bering Sea. We determined the genetic stock composition of immature chum salmon based on the previous mitochondria DNA baseline. Each regional estimate was computed based on the conditional maximum likelihood method using 1,000 bootstrap resampling and then pooled to the major regional groups: Korea - Japan - Primorie (KJP) / Russia (RU) / Northwest Alaska (NWA) / Alaska Peninsula - Southcentral Alaska - Southeast Alaska - British Columbia - Washington (ONA). The stock composition of immature chum salmon in the western Bering Sea was a mix of 0.424 KJP, 0.421 RU, 0.116 NWA, and 0.039 ONA stocks. During the study period, the contribution of Asian chum salmon stocks gradually changed from RU to KJP stock. In addition, North American populations from NWA and ONA were small but present near the vicinity of the Russian coast and the Commander Islands, suggesting that the study areas in the western Bering Sea were an important migration route for Pacific chum salmon originating both from Asia and North America during the months of September and October. These results make it possible to better understand the chum salmon stock composition of the mixed-stock fisheries in the western Bering Sea and the stock-specific distribution pattern of chum salmon on the high-seas.

Triggered tremor sweet spots in Alaska

USGS Publications Warehouse

Gomberg, Joan; Prejean, Stephanie

2013-01-01

To better understand what controls fault slip along plate boundaries, we have exploited the abundance of seismic and geodetic data available from the richly varied tectonic environments composing Alaska. A search for tremor triggered by 11 large earthquakes throughout all of seismically monitored Alaska reveals two tremor “sweet spots”—regions where large-amplitude seismic waves repeatedly triggered tremor between 2006 and 2012. The two sweet spots locate in very different tectonic environments—one just trenchward and between the Aleutian islands of Unalaska and Akutan and the other in central mainland Alaska. The Unalaska/Akutan spot corroborates previous evidence that the region is ripe for tremor, perhaps because it is located where plate-interface frictional properties transition between stick-slip and stably sliding in both the dip direction and laterally. The mainland sweet spot coincides with a region of complex and uncertain plate interactions, and where no slow slip events or major crustal faults have been noted previously. Analyses showed that larger triggering wave amplitudes, and perhaps lower frequencies (<~0.03 Hz), may enhance the probability of triggering tremor. However, neither the maximum amplitude in the time domain or in a particular frequency band, nor the geometric relationship of the wavefield to the tremor source faults alone ensures a high probability of triggering. Triggered tremor at the two sweet spots also does not occur during slow slip events visually detectable in GPS data, although slow slip below the detection threshold may have facilitated tremor triggering.

Publications - GMC 16 | Alaska Division of Geological & Geophysical Surveys

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Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska Geologic Data Index (AGDI) Volcanology Alaska Volcano Observatory (AVO) Mineral Resources Alaska's Mineral and Facilities Staff Seismic and Well Data Data Reports Contact Us Frequently Asked Questions Ask a

Alaska Department of Revenue - Alaska Film Office

Science.gov Websites

State Employees Alaska Film Office Alaska Film Office State of Alaska HOME CREDIT PROGRAM PUBLIC REPORTING CPA ECONOMIC DEVELOPMENT CONTACT US State of Alaska > Department of Revenue > Alaska Film Office > Text Size: A+ | A- | A Text Only Effective July 1, 2015, the film production incentive

Publications - RDF 2005-4 | Alaska Division of Geological & Geophysical

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District; Trace Elements; Trace Metals; Tungsten; Uranium; Vanadium; Yttrium; Zinc; Zirconium Top of Page Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

Publications - RDF 2010-2 | Alaska Division of Geological & Geophysical

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Prospect; Trace Elements; Trace Metals; Triassic; Wrangellia Terrane; geoscientificInformation Top of Page Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

Publications - RDF 2000-4 | Alaska Division of Geological & Geophysical

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Oxides; Palladium; Platinum; Rare Earth Elements; STATEMAP Project; Trace Metals Top of Page Department Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

Publications - RDF 2015-6 | Alaska Division of Geological & Geophysical

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Sediments; Trace Elements; Trace Geochemical; Trace Metals; geoscientificInformation Top of Page Department Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

Reconnaissance engineering geology of Sitka and vicinity, Alaska, with emphasis on evaluation of earthquake and other geologic hazards

USGS Publications Warehouse

Yehle, Lynn A.

1974-01-01

A program to study the engineering geology of most of the larger Alaska coastal communities and to evaluate their earthquake and other geologic hazards was started following the 1964 Alaska earthquake; this report about Sitka and vicinity is a product of that program. Field-study methods were of a reconnaissance nature, and thus the interpretations in the report are subject to revision as further information becomes available. This report can provide broad geologic guidelines for planners and engineers during preparation of land-use plans. The use of this information should lead to minimizing future loss of life and property due to geologic hazards, especially during very large earthquakes. Landscape of Sitka and surrounding area is characterized by numerous islands and a narrow strip of gently rolling ground adjacent to rugged mountains; steep valleys and some fiords cut sharply into the mountains. A few valley floors are wide and flat and grade into moderate-sized deltas. Glaciers throughout southeastern Alaska and elsewhere became vastly enlarged during the Pleistocene Epoch. The Sitka area presumably was covered by ice several times; glaciers deeply eroded some valleys and removed fractured bedrock along some faults. The last major deglaciation occurred sometime before 10,000 years ago. Crustal rebound believed to be related to glacial melting caused land emergence at Sitka of at least 35 feet (10.7 m) relative to present sea level. Bedrock at Sitka and vicinity is composed mostly of bedded, hard, dense graywacke and some argillite. Beds strike predominantly northwest and are vertical or steeply dipping. Locally, bedded rocks are cut by dikes of fine-grained igneous rock. Host bedrock is of Jurassic and Cretaceous age. Eight types of surficial deposits of Quaternary age were recognized. Below altitudes of 3S feet (10.7 m), the dominant deposits are those of modern and elevated shores and deltas; at higher altitudes, widespread muskeg overlies a mantle of volcanic ash which commonly overlies glacial drift. Alluvial deposits are minor. Man-emplaced embankment fill, chiefly sandy gravel, covers many muskeg and former offshore areas; quarried blocks of graywacke are placed to form breakwaters and to edge large areas of embankment fill and modified ground. The geologic structure of the area is known only in general outlines. Most bedded Mesozoic rocks probably are part of broad northwest-trending complexes of anticlines and synclines. Intrusion of large bodies of plutonic igneous rocks occurred in Tertiary and Cretaceous time. Extensive faulting is suggested by the numerous linear to gently curving patterns of some fiords, lakes, and valleys, and by a group of Holocene volcanoes and cinder cones. Two major northwest-striking fault zones are most prominent: (1) the apparently inactive Chichagof-Sitka fault, about 2.5 miles (4.0 km) northeast of Sitka, and {2) part of the active 800-mile- (1,200-km) long Fairweather-Queen Charlotte Islands fault system, lying about 30 miles (48 km) southwest of the city. Many earthquakes have been reported as felt at Sitka since 1832, when good records were first maintained; several shocks were very strong, but none of them caused severe damage. The closest major earthquake (magnitude about 7.3) causing some damage to the city occurred July 30, 1972, and had an epicenter about 30 miles (48 km) to the southwest. Movement along the Fairweather-Queen Charlotte Islands fault system apparently caused most of the earthquakes felt at Sitka. The probability of destructive earthquakes at Sitka is unknown. The tectonics of the region and the seismic record suggest that sometime in the future an earthquake of a magnitude of about 8 and related to the Fairweather-Queen Charlotte Islands fault system probably will occur in or near the area. Effects from some nearby major earthquakes could cause substantial damage at Sitka. Eight possible effects are as follows: 1. Sudden dis

Determinants of conifer distributions across peatland to forest gradients in the coastal temperate rainforest of southeast Alaska

Treesearch

Sarah M. Bisbing; David J. Cooper; David V. D' Amore; Kristin N. Marshall

2016-01-01

Wetland determination relies on assumptions that site hydrologic and edaphic conditions limit plant species to certain environments. For example, using species' wetland indicator status for wetland determination assumes that tolerance of wetland conditions best explains distributional patterns. However, abiotic and biotic factors often interact to create complex...

Changes in vegetation in northern Alaska under scenarios of climate change, 2003-2100: implications for climate feedbacks

Treesearch

E.S. Euskirchen; A.D. McGuire; F.S. III Chapin; S. Yi; C.C. Thompson

2009-01-01

Assessing potential future changes in arctic and boreal plant species productivity, ecosystem composition, and canopy complexity is essential for understanding environmental responses under expected altered climate forcing. We examined potential changes in the dominant plant functional types (PFTs) of the sedge tundra, shrub tundra, and boreal forest ecosystems in...

Tackling the Law and Raising the Issues: Summer Program Prepares Students.

ERIC Educational Resources Information Center

Bowannie, Mary

2003-01-01

An intensive 8-week summer program in New Mexico prepares American Indian and Alaska Native students to succeed in law school, focusing on law research, analysis, and writing. Two program graduates who went on to complete law school discuss the complexities of federal Indian law and the Native lawyers' responsibility to their communities--an…

Building resilience through interlocal relations: case studies of polar bear and walrus management in the Bering Strait

Treesearch

Chanda L. Meek; Amy Lauren Lovecraft; Martin D. Robards; Gary P. Kofinas

2008-01-01

Arctic coastal communities in the Bering Strait region of Alaska (USA) and Chukotka (Russia) share a close relationship with their natural environments that can be characterized as a social-ecological system. This system is complex, featuring changing ecosystem conditions, multiple jurisdictions, migratory animal populations, and several cultures. We argue that...

ARC-2010-ACD10-0244-003

NASA Image and Video Library

2010-10-18

From left, Giovanni Minelli with the NASA's Ames Research Center; Center: Kitty Sedam with Aerospace Corp.; and Charlie Friedericks with Ames inspect the packing list and instructions for the Ames-managed O/OREOS and NanoSail-D from NASA's Marshall Space Flgith Center nano satellites at Kodiak Launch Complex, Alaska . Image credit: U.S. Air Force/Lou Hernandez

75 FR 41424 - Fisheries of the Exclusive Economic Zone Off Alaska; Skates Management in the Groundfish...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-16

... and AMs must be implemented by January 1, 2011. Skate, shark, sculpin, and octopus groups are currently managed as a complex in the ``other species'' category in the BSAI. In the GOA, shark, sculpin...'' category combines the management of short-lived invertebrates (squids and octopuses) with long-lived fish...

Warm Mix Asphalt

DOT National Transportation Integrated Search

2009-04-17

State of Alaska State of Alaska - Warm Mix Project Warm Mix Project: Location - Petersburg, Alaska which is Petersburg, Alaska which is located in the heart of Southeast Alaska located in the heart of Southeast Alaska's Inside Passage at the tip of M...

Deciphering the Transitional Tectonics of the Southern Alaska Margin Through Gulf Sedimentology and Geophysics: IODP Expedition 341

NASA Astrophysics Data System (ADS)

Reece, R.; Gulick, S. P. S.; Jaeger, J. M.

2014-12-01

Southern Alaska is a complex amalgam of tectonic environments, centered on the subduction/collision of the Yakutat Block with North America. Along the Aleutians in the west, the Pacific Plate subducts normally beneath North America, with a gradually shallowing subduction angle towards the Yakutat Terrane to the east. The western region of the Yakutat Block undergoes nearly flat-slab subduction beneath North America, whereas it transitions to collision in the northeast, which is the primary driver for the growth of the Chugach-St. Elias orogen. Farther to the east, the collisional system transitions to a transform boundary with the Fairweather-Queen Charlotte fault system. The collisional system contributes to farfield tectonic effects in many regions, including northern Alaska and the Pacific Plate, but also combines with glaciation to drive sedimentation in the Gulf of Alaska. Glaciation has periodically increased in the St. Elias Range since the Miocene, but began dominating erosion and spurred enhanced exhumation since the intensification of Northern Hemisphere glaciation, at ~2.5 Ma. Results from IODP Expedition 341 show the first appearance of ice-rafted debris and a doubling of Gulf sedimentation at site U1417 at this age, and a major increase in sedimentation at ~1 Ma at sites U1417 and U1418. Glacigenic sediment flux into the Gulf of Alaska represents the majority of accumulation in the deepwater Surveyor Fan, and was the impetus for formation of the Surveyor Channel system. Climate events correlate to three major differentiable sequences across the Surveyor Fan that have been previously mapped using seismic reflection profiles. The change in morphology observed throughout the sequences allows us to characterize the influence that a glaciated orogen can have in shaping margin processes and the sediment pathways from source to sink. IODP Expedition 341 results allow us to now apply this method at higher resolution time scales (i.e., 100 kyr). We will explore changes in fan geomorphology observed in seismic reflection data to decipher changes in southern Alaska tectonics and climate, and to show the effect of those changes on deepwater sedimentary systems.

An evaluation of petrogenic hydrocarbons in northern Gulf of Alaska continental shelf sediments - The role of coastal oil seep inputs

USGS Publications Warehouse

Short, J.W.; Kolak, J.J.; Payne, J.R.; Van Kooten, G. K.

2007-01-01

We compared hydrocarbons in water, suspended particulate matter (SPM), and riparian sediment collected from coastal watersheds along the Yakataga foreland with corresponding hydrocarbons in Gulf of Alaska benthic sediments. This comparison allows an evaluation of hydrocarbon contributions to marine sediments from natural oil seeps, coal and organic matter (e.g., kerogen) associated with eroding siliciclastic rocks. The samples from oil seeps show extensive loss of low-molecular weight n-alkanes (

Habitat quality of the coastal southeastern Bering Sea for juvenile flatfishes from the relationships between diet, body condition and prey availability

NASA Astrophysics Data System (ADS)

Yeung, Cynthia; Yang, Mei-Sun

2017-01-01

The distribution and body condition of juvenile northern rock sole (NRS), Lepidopsetta polyxystra, and yellowfin sole (YFS), Limanda aspera, were studied in relation to prey availability across the coastal shelf at the Alaska Peninsula boundary of the eastern Bering Sea (EBS) to assess spatial variability in habitat quality. Juveniles of ≤ 20 cm and adults of ≥ 30 cm total length were collected from bottom trawl catch samples at stations located 10 to 120 km from the Alaska Peninsula coast, and in bottom depths of 28 to 85 m. Stomach contents and stable isotopes of carbon and nitrogen from muscle tissue were analyzed to describe diet composition. The quantity and quality of prey did not significantly affect the distribution of juvenile NRS and YFS. Spatial mismatch between the diet composition and the infauna prey assemblage suggested that prey availability was not limiting across the area, allowing fish to select for prey, presumably to maximize net energy gain. The body condition of juvenile NRS was higher in the eastern section of the area (Bristol Bay) - where they shared spatial and dietary niches with juvenile YFS, than in the west section (Unimak Island) where juvenile YFS were largely absent. A difference in body condition suggests that habitat quality may be higher in Bristol Bay. For NRS, stomach contents and stable isotopes in muscle tissue indicated an ontogenetic diet shift from amphipods to polychaetes from juvenile to adult stages. In contrast, for YFS, amphipods seemed to remain the primary prey and polychaetes the least important prey from juvenile to adult stage. Given that the high prey availability found in this south coastal area of EBS extends to areas across the EBS shelf, favorable habitat for juvenile flatfishes should be extensive. However, much of this potential juvenile habitat is underutilized by NRS, which were mainly limited to Bristol Bay and the Alaska Peninsula, whereas YFS did extend north over 500 km from Bristol Bay along the inner shelf domain (≤ 50 m deep). Abiotic factors, particularly ocean currents and water temperature, may be more significant than prey availability in the spatial distribution of juveniles. Thus, changes in the hydrographic and thermal regime of the EBS are likely to impact juvenile flatfish distribution and habitat productivity.

Proceedings of the North Aleutian Basin information status and research planning meeting.

DOE Office of Scientific and Technical Information (OSTI.GOV)

LaGory, K. E.; Krummel, J. R.; Hayse, J. W.

2007-10-26

The North Aleutian Basin Planning Area of the Minerals Management Service (MMS) is a large geographic area with significant ecological and natural resources. The Basin includes most of the southeastern part of the Bering Sea continental shelf including all of Bristol Bay. The area supports important habitat for a wide variety of species and globally significant habitat for birds and marine mammals including federally listed species. Villages and communities of the Alaska Peninsula and other areas bordering or near the Basin rely on its natural resources (especially commercial and subsistence fishing) for much of their sustenance and livelihood. The offshoremore » area of the North Aleutian Basin is considered to have important hydrocarbon reserves, especially natural gas. In 2006, the MMS released a draft proposed program, Outer Continental Shelf Oil and Gas Leasing Program, 2007-2012 and an accompanying draft programmatic environmental impact statement (EIS). The draft proposed program identified two lease sales proposed in the North Aleutian Basin in 2010 and 2012, subject to restrictions. The area proposed for leasing in the Basin was restricted to the Sale 92 Area in the southwestern portion. Additional EISs will be needed to evaluate the potential effects of specific lease actions, exploration activities, and development and production plans in the Basin. A full range of updated multidisciplinary scientific information will be needed to address oceanography, fate and effects of oil spills, marine ecosystems, fish, fisheries, birds, marine mammals, socioeconomics, and subsistence in the Basin. Scientific staff at Argonne National Laboratory (Argonne) were contracted to assist the MMS Alaska Outer Continental Shelf (OCS) Region in identifying and prioritizing information needs related to the North Aleutian Basin and potential future oil and gas leasing and development activities. The overall approach focused on three related but separate tasks: (1) identification and gathering of relevant literature; (2) synthesis and summary of the literature; and (3) identification and prioritization of information needs. To assist in gathering this information, MMS convened the North Aleutian Basin Information Status and Research Planning Meeting, held in Anchorage, Alaska, from November 28 through December 1, 2006; this report presents a summary of that meeting. The meeting was the primary method used to gather input from stakeholders and identify information needs and priorities for future inventory, monitoring, and research related to potential leasing and oil and gas developments in the North Aleutian Basin.« less

Publications - SR 37 | Alaska Division of Geological & Geophysical Surveys

Science.gov Websites

Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska Section; Resource Assessment; Tyonek Formation; Type Section Top of Page Department of Natural Resources State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Surveys Home

Presentations - Twelker, Evan and others, 2014 | Alaska Division of

Science.gov Websites

Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Details Title: Preliminary results from 2014 geologic mapping in the Talkeetna Mountains, Alaska Lande, Lauren, 2014, Preliminary results from 2014 geologic mapping in the Talkeetna Mountains, Alaska

Publications - GMC 410 | Alaska Division of Geological & Geophysical

Science.gov Websites

) Keywords Geochemistry; Rare Earth Elements Top of Page Department of Natural Resources, Division of Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

Publications - RDF 2012-3 | Alaska Division of Geological & Geophysical

Science.gov Websites

Assessment Project; Trace Elements; geoscientificInformation Top of Page Department of Natural Resources Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

Publications - GMC 409 | Alaska Division of Geological & Geophysical

Science.gov Websites

) Keywords Geochemistry; Rare Earth Elements Top of Page Department of Natural Resources, Division of Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

Publications - RDF 2016-2 | Alaska Division of Geological & Geophysical

Science.gov Websites

, Major-oxide and trace-element geochemistry of mafic rocks in the Carboniferous Lisburne Group, Ivishak Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

Publications - RDF 2004-2 | Alaska Division of Geological & Geophysical

Science.gov Websites

; Trace Elements; Trace Metals; Tungsten; Vanadium; Yttrium; Zinc; Zirconium Top of Page Department of Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

Publications - GMC 183 | Alaska Division of Geological & Geophysical

Science.gov Websites

Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical materials: AK State C #1, Bush Federal #1, Echooka Unit #1, Fin Creek Unit #1, E. De K. Leffingwell #1, Nora

Multilocus phylogeny and coalescent species delimitation in Kotschy's gecko, Mediodactylus kotschyi: Hidden diversity and cryptic species.

PubMed

Kotsakiozi, Panayiota; Jablonski, Daniel; Ilgaz, Çetin; Kumlutaş, Yusuf; Avcı, Aziz; Meiri, Shai; Itescu, Yuval; Kukushkin, Oleg; Gvoždík, Václav; Scillitani, Giovanni; Roussos, Stephanos A; Jandzik, David; Kasapidis, Panagiotis; Lymberakis, Petros; Poulakakis, Nikos

2018-08-01

Kotschy's Gecko, Mediodactylus kotschyi, is a small gecko native to southeastern Europe and the Levant. It displays great morphological variation with a large number of morphologically recognized subspecies. However, it has been suggested that it constitutes a species complex of several yet unrecognized species. In this study, we used multilocus sequence data (three mitochondrial and three nuclear gene fragments) to estimate the phylogenetic relationships of 174 specimens from 129 sampling localities, covering a substantial part of the distribution range of the species. Our results revealed high genetic diversity of M. kotschyi populations and contributed to our knowledge about the phylogenetic relationships and the estimation of the divergence times between them. Diversification within M. kotschyi began approximately 15 million years ago (Mya) in the Middle Miocene, whereas the diversification within most of the major clades have been occurred in the last 5 Mya. Species delimitation analysis suggests there exists five species within the complex, and we propose to tentatively recognize the following taxa as full species: M. kotschyi (mainland Balkans, most of Aegean islands, and Italy), M. orientalis (Levant, Cyprus, southern Anatolia, and south-eastern Aegean islands), M. danilewskii (Black Sea region and south-western Anatolia), M. bartoni (Crete), and M. oertzeni (southern Dodecanese Islands). This newly recognized diversity underlines the complex biogeographical history of the Eastern Mediterranean region. Copyright © 2018 Elsevier Inc. All rights reserved.

A whole ecosystem approach to studying climate change in interior Alaska

USGS Publications Warehouse

Riggins, Susan; Striegl, Robert G.; McHale, Michael

2011-01-01

Yukon River Basin Principal Investigators Workshop; Portland, Oregon, 18-20 January 2011; High latitudes are known to be particularly susceptible to climate warming, leading to an emphasis of field and modeling research on arctic regions. Subarctic and boreal regions such as the Yukon River Basin (YRB) of interior Alaska and western Canada are less well studied, although they encompass large areas that are vulnerable to changes in forest composition, permafrost distribution, and hydrology. There is an urgent need to understand the resiliency and vulnerability of these complex ecosystems as well as their feedbacks to the global climate system. Consequently, U.S. Geological Survey scientists, with other federal agency, university, and private industry partners, is focusing subarctic interdisciplinary studies on the Beaver Creek Wild and Scenic River watershed (http://www.blm.gov/pgdata/content/ak/en/prog/nlcs/beavercrk_nwsr.html) and Yukon Flats National Wildlife Refuge (http://yukonflats.fws.gov/) in the YRB, south and west of Fort Yukon, Alaska. These areas are national treasures of wetlands, lakes, and uplands that support large populations of wildlife and waterfowl and are home to vibrant native Alaskan communities that depend on the area for a subsistence lifestyle.

Potential seismic hazards and tectonics of the upper Cook Inlet basin, Alaska, based on analysis of Pliocene and younger deformation

USGS Publications Warehouse

Haeussler, Peter J.; Bruhn, Ronald L.; Pratt, Thomas L.

2000-01-01

The Cook Inlet basin is a northeast-trending forearc basin above the Aleutian subduction zone in southern Alaska. Folds in Cook Inlet are complex, discontinuous structures with variable shape and vergence that probably developed by right-transpressional deformation on oblique-slip faults extending downward into Mesozoic basement beneath the Tertiary basin. The most recent episode of deformation may have began as early as late Miocene time, but most of the deformation occurred after deposition of much of the Pliocene Sterling Formation. Deformation continued into Quaternary time, and many structures are probably still active. One structure, the Castle Mountain fault, has Holocene fault scarps, an adjacent anticline with flower structure, and historical seismicity. If other structures in Cook Inlet are active, blind faults coring fault-propagation folds may generate Mw 6–7+ earthquakes. Dextral transpression of Cook Inlet appears to have been driven by coupling between the North American and Pacific plates along the Alaska-Aleutian subduction zone, and by lateral escape of the forearc to the southwest, due to collision and indentation of the Yakutat terrane 300 km to the east of the basin.

Genetic variation in domestic reindeer and wild caribou in Alaska

USGS Publications Warehouse

Cronin, M.; Renecker, L.; Pierson, Barbara J.; Patton, J.C.

1995-01-01

Reindeer were introduced into Alaska 100 years ago and have been maintained as semidomestic livestock. They have had contact with wild caribou herds, including deliberate cross-breeding and mixing in the wild. Reindeer have considerable potential as a domestic animal for meat or velvet antler production, and wild caribou are important to subsistence and sport hunters. Our objective was to quantify the genetic relationships of reindeer and caribou in Alaska. We identified allelic variation among five herds of wild caribou and three herds of reindeer with DNA sequencing and restriction enzymes for three loci: a DQA locus of the major histocompatibility complex (Rata-DQA1), k-casein and the D-loop of mitochondrial DNA. These loci are of interest because of their potential influence on domestic animal performance and the fitness of wild populations. There is considerable genetic variation in reindeer and caribou for all three loci, including five, three and six alleles for DQA, k-casein and D-loop respectively. Most alleles occur in both reindeer and caribou, which may be the result of recent common ancestry or genetic introgression in either direction. However, allele frequencies differ considerably between reindeer and caribou, which suggests that gene flow has been limited.

Regional patterns of Mesozoic-Cenozoic magmatism in western Alaska revealed by new U-Pb and 40Ar/39Ar ages: Chapter D in Studies by the U.S. Geological Survey in Alaska, vol. 15

USGS Publications Warehouse

Bradley, Dwight C.; Miller, Marti L.; Friedman, Richard M.; Layer, Paul W.; Bleick, Heather A.; Jones, James V.; Box, Steven E.; Karl, Susan M.; Shew, Nora B.; White, Timothy S.; Till, Alison B.; Dumoulin, Julie A.; Bundtzen, Thomas K.; O'Sullivan, Paul B.; Ullrich, Thomas D.

2017-03-02

In support of regional geologic framework studies, we obtained 50 new argon-40/argon-39 (40Ar/39Ar) ages and 33 new uranium-lead (U-Pb) ages from igneous rocks of southwestern Alaska. Most of the samples are from the Sleetmute and Taylor Mountains quadrangles; smaller collections or individual samples are from the Bethel, Candle, Dillingham, Goodnews Bay, Holy Cross, Iditarod, Kantishna River, Lake Clark, Lime Hills, McGrath, Medfra, Talkeetna, and Tanana quadrangles.A U-Pb zircon age of 317.7±0.6 million years (Ma) reveals the presence of Pennsylvanian intermediate igneous (probably volcanic) rocks in the Tikchik terrane, Bethel quadrangle. A U-Pb zircon age of 229.5±0.2 Ma from gabbro intruding the Rampart Group of the Angayucham-Tozitna terrane, Tanana quadrangle, confirms and tightens a previously cited Triassic age for this intrusive suite. A fresh mafic dike in Goodnews Bay quadrangle yielded a 40Ar/39Ar whole rock age of 155.0±1.9 Ma; this establishes a Jurassic or older age for the previously unconstrained (Paleozoic? to Mesozoic?) sandstone unit that it intrudes. A thick felsic tuff in the Gemuk Group in Taylor Mountains quadrangle yielded a U-Pb zircon age of 153.0±2.0 Ma, extending the age of magmatism in this part of the Togiak terrane back into the Late Jurassic. We report three new U-Pb zircon ages between 120 and 110 Ma—112.0±0.9 Ma from syenite in the Candle quadrangle, 114.9±0.3 Ma from orthogneiss assigned to the Ruby terrane in Iditarod quadrangle, and 116.6±0.1 Ma from a gabbro of the Dishna River mafic-ultramafic complex in Iditarod quadrangle. The latter result requires a substantial age revision, from Triassic to Cretaceous, for at least some rocks that have been mapped as the Dishna River mafic-ultramafic complex. A tuff in the Upper Cretaceous Kuskokwim Group yielded a U-Pb zircon (sensitive high-resolution ion microprobe, SHRIMP) age of 88.3±1.0 Ma; we speculate that the eruptive source was an arc along the trend of the Pebble porphyry copper deposit along the Gulf of Alaska continental margin. More than half of the new ages fall between 75 and 65 Ma, confirming the existence, based on conventional potassium-argon (K-Ar) ages, of a 70-Ma igneous flare-up across southwestern Alaska. Our new ages hint that during this pulse, the locus of magmatism shifted toward the Gulf of Alaska, that is, toward a more outboard position. This shift is consistent with the hypothesis that magmatism was the product of rollback of a subducted slab, which at that time would have been the Resurrection Plate. Intrusive rocks in the Taylor Mountains and Sleetmute quadrangles in the age range of 63 to 59 Ma were emplaced shortly before the onset of ridge subduction as dated by near-trench plutons in the adjacent part of the Chugach accretionary complex. Southwestern Alaska at this time would have been positioned above a very young subducted slab belonging to the Resurrection Plate; magmas, in this scenario, were generated near the edge of the slab window related to ridge subduction. A 56.3±0.2 Ma granite in Taylor Mountains quadrangle and a 54.7±0.7 Ma ashfall tuff in McGrath quadrangle were likely emplaced above the Resurrection-Kula slab window, which by this time is inferred to have entered the region. Another ashfall tuff in McGrath quadrangle, at 42.8±0.5 Ma, likely belongs to the Meshik Arc, the product of renewed subduction after inferred passage of the slab window. A 49.0±0.3-Ma rhyolite in Taylor Mountains quadrangle is about the age of the transition from slab window to renewed subduction. Two plutons in the western Alaska Range, at 31.8±0.4 and 30.9±0.6 Ma, belong to a suite of gabbro to peralkaline granite of unknown origin. Finally, a 4.6±0.1-Ma basalt from a flow in Taylor Mountains quadrangle belongs to the Neogene basaltic province of western Alaska. These rocks were erupted in a distal retroarc setting; the cause of magmatism is unknown. 

Geochemical and Sulfur-Isotopic Signatures of Volcanogenic Massive Sulfide Deposits on Prince of Wales Island and Vicinity, Southeastern Alaska

USGS Publications Warehouse

Slack, John F.; Shanks, Wayne C.; Karl, Susan M.; Gemery, Pamela A.; Bittenbender, Peter E.; Ridley, W. Ian

2007-01-01

Stratabound volcanogenic massive sulfide (VMS) deposits on Prince of Wales Island and vicinity, southeastern Alaska, occur in two volcanosedimentary sequences of Late Proterozoic through Cambrian and of Ordovician through Early Silurian age. This study presents geochemical data on sulfide-rich samples, in situ laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of sulfide minerals, and sulfur-isotopic analyses of sulfides and sulfates (barite) for identifying and distinguishing between primary sea-floor signatures and later regional metamorphic overprints. These datasets are also used here in an attempt to discriminate the VMS deposits in the older Wales Group from those in the younger Moira Sound unit (new informal name). The Wales Group and its contained VMS deposits have been multiply deformed and metamorphosed from greenschist to amphibolite grade, whereas the Moira Sound unit and related VMS deposits are less deformed and generally less metamorphosed (lower to middle greenschist grade). Variations in the sulfide mineral assemblages and textures of the VMS deposits in both sequences reflect a combination of processes, including primary sea-floor mineralization and sub-sea-floor zone refining, followed by metamorphic recrystallization. Very coarse grained (>1 cm diam) sulfide minerals and abundant pyrrhotite are restricted to VMS deposits in a small area of the Wales Group, at Khayyam and Stumble-On, which record high-grade metamorphism of the sulfides. Geochemical and sulfur-isotopic data distinguish the VMS deposits in the Wales Group from those in the Moira Sound unit. Although base- and precious-metal contents vary widely in sulfide-rich samples from both sequences, samples from the Moira Sound generally have proportionately higher Ag contents relative to base metals and Au. In situ LA-ICP-MS analysis of trace elements in the sulfide minerals suggests that primary sea-floor hydrothermal signatures are preserved in some samples (for example, Mn, As, Sb, and Tl in pyrite from the Moira Sound unit), whereas in other samples the signatures are varyingly annealed, owing to metamorphic overprinting. A limited LA-ICP-MS database for sphalerite indicates that low-Fe sphalerite is preferentially associated with the most Au rich deposits, the Niblack and Nutkwa. Sulfur-isotopic values for sulfide minerals in the VMS deposits in the Wales Group range from 5.9 to 17.4 permil (avg 11.5?2.7 permil), about 5 to 6 permil higher than those in the Moira Sound unit, which range from -2.8 to 10.4 permil (avg 6.1?4.0 permil). This difference in 34Ssulfide values reflects a dominantly seawater sulfate source of the sulfides and is linked to the 34S values of contemporaneous seawater sulfate, which were slightly higher during the Late Proterozoic through Cambrian than during the Ordovician through Early Silurian.

Alaska telemedicine: growth through collaboration.

PubMed

Patricoski, Chris

2004-12-01

The last thirty years have brought the introduction and expansion of telecommunications to rural and remote Alaska. The intellectual and financial investment of earlier projects, the more recent AFHCAN Project and the Universal Service Administrative Company Rural Health Care Division (RHCD) has sparked a new era in telemedicine and telecommunication across Alaska. This spark has been flamed by the dedication and collaboration of leaders at he highest levels of organizations such as: AFHCAN member organizations, AFHCAN Office, Alaska Clinical Engineering Services, Alaska Federal Health Care Partnership, Alaska Federal Health Care Partnership Office, Alaska Native health Board, Alaska Native Tribal health Consortium, Alaska Telehealth Advisory Council, AT&T Alascom, GCI Inc., Health care providers throughout the state of Alaska, Indian Health Service, U.S. Department of Health and Human Services, Office of U.S. Senator Ted Steens, State of Alaska, U.S. Department of Homeland Security--United States Coast Guard, United States Department of Agriculture, United States Department of Defense--Air Force and Army, United States Department of Veterans Affairs, University of Alaska, and University of Alaska Anchorage. Alaska now has one of the largest telemedicine programs in the world. As Alaska moves system now in place become self-sustaining, and 2) collaborating with all stakeholders in promoting the growth of an integrated, state-wide telemedicine network.

Integrated evaluation of the vulnerability to thermokarst disturbance and its implications for the regional carbon balance in boreal Alaska

NASA Astrophysics Data System (ADS)

Helene, G.; Lara, M. J.; McGuire, A. D.; Euskirchen, E. S.; Bolton, W. R.; Romanovsky, V. E.

2017-12-01

Our capacity to project future ecosystem trajectories in northern permafrost regions depends on our ability to characterize complex interactions between climatic and ecological processes at play in the soil, the vegetation, and the atmosphere. We present a study that uses remote sensing analyses, field observations, and data synthesis to inform models for the prediction of ecosystem responses to climate change in the boreal zone of Alaska. Recent warming, altered precipitation and fire regimes are driving permafrost degradation, threatening to mobilize vast reservoirs of ancient carbon previously protected from decomposition. Although large scale, progressive, top-down permafrost thaw have been well studied and represented in high-latitude ecosystem models, the consequences of abrupt and local thermokarst disturbances (TK) are less well understood. To fill this gap, we conducted a detection analysis characterizing 60 years of land cover change in the Tanana Flats, a wetland complex subjected to TK disturbance in Interior Alaska, using aerial and satellite images. We observed a nonlinear loss of permafrost plateau forest associated with TK and driven by precipitation and forest fragmentation. The results of this analysis were integrated into the Alaska Thermokarst Model (ATM), a state-and-transition model that simulates land cover change associated with TK disturbance. Thermokarst-related land cover change was simulated from 2000 to 2100 across the Tanana Flats. By 2100, the model predicts a mean decrease of 7.4% (sd 1.8%) in permafrost plateau forests associated with an increase in TK fens and bogs. Transitions from permafrost plateau forests to TK wetlands are accompanied with changes in physical and biogeochemical processes affecting ecosystem carbon balance. We evaluated the consequences of TK disturbances on the regional carbon balance by coupling outputs from the ATM and from a process-based biogeochemical model. We used long-term field observations of vegetation and soil physical and biogeochemical attributes to develop new parameterizations for TK wetlands and permafrost plateau forest land cover types. Preliminary simulations from 2000 to 2100 estimate that the conversion of permafrost plateau forest to young TK wetlands would result in a 7.5% (sd 3.5%) decrease in Net Ecosystem Exchange.

Publications - PDF 98-36A | Alaska Division of Geological & Geophysical

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Oxides; Rocks; STATEMAP Project; Trace Elements Top of Page Department of Natural Resources, Division of Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

Publications - GMC 370 | Alaska Division of Geological & Geophysical

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(249.0 K) Keywords Rare Earth Elements Top of Page Department of Natural Resources, Division of Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical

Publications - GMC 159 | Alaska Division of Geological & Geophysical

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Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical State #1, Kuparuk Unit #1, Mikkelsen Bay State 13-09-19, Ravik State #1, Pt. Thomson Unit #2, West

Publications - SR 32 | Alaska Division of Geological & Geophysical Surveys

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DGGS SR 32 Publication Details Title: Oil and gas basins map of Alaska Authors: Ehm, Arlen Publication ): Alaska Statewide Bibliographic Reference Ehm, Arlen, 1983, Oil and gas basins map of Alaska: Alaska Sheets Sheet 1 Oil and gas basins map of Alaska, scale 1:2,500,000 (21.0 M) Keywords Alaska Statewide

Substantiating the Need to Apply a Sociocultural Lens to the Preparation of Teachers in an Effort to Achieve Science Reform

ERIC Educational Resources Information Center

Zapata, Mara

2013-01-01

This qualitative, sociocultural study examines how teacher preparation programs may have deliberate impact on science reform by unearthing the complex layers of diversity inherent in the contextual reality of education. This study was conducted in one of the largest school districts in the Southeastern United States, serving a predominately…

A Case Study of Middle School Teachers' Preparations for High-Stakes Assessments

ERIC Educational Resources Information Center

Yeary, David Lee

2017-01-01

Students, educators, and schools across the country have been presented with challenges as a result of rigorous standards and high-complexity tests. The problem addressed in this case study was that teachers in a rural middle school in a southeastern state were preparing students to take a new high-stakes state-mandated assessment in English…

Differentiation of Corynespora cassiicola and Cercospora sp. in leaf-spot diseases of Hydrangea macrophylla using a PCR-mediated method

Treesearch

M. T. Mmbaga; L. Mackasmiel; Ned Klopfenstein

2015-01-01

Corynespora cassiicola and Cercospora sp. have been identified as the most prevalent and destructive leaf-spot pathogens of garden hydrangea [Hydrangea macrophylla (Thunberg) Seringe] in the southeastern USA, but they are often difficult to accurately detect and distinguish because they often occur together in a disease complex with other pathogenic leaf-spot...

Predation of the newly invasive pest Megacopta cribraria (F.) (Hemiptera: Plataspidae) in soybean habitats adjacent to cotton by a complex of predators

USDA-ARS?s Scientific Manuscript database

The kudzu bug, Megacopta cribraria (F.) (Hemiptera: Plataspidae), is a newly-invasive exotic insect found primarily on kudzu, but also on soybean, in the southeastern United States. We used molecular gut-content analysis to document predation on this pest by insects and spiders in soybean; and to d...

State of Alaska

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Alaska Railroad Alaska Maps Alaska Travel Safety Information Alaska Fish and Game Alaska Facts & Month Services How Do I? Education Health Jobs Safety How Do I? Apply for a Permanent Fund Dividend File Information More Dept. of Commerce, Comm... More Dept. of Labor & Workforce Dev. Safety 511 - Traveler

Publications - DDS 7 | Alaska Division of Geological & Geophysical Surveys

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Portal Climate and Cryosphere Hazards Coastal Hazards Program Guide to Geologic Hazards in Alaska DGGS DDS 7 Publication Details Title: Alaska Coastal Profile Tool (ACPT) Authors: DGGS Staff ): Alaska Statewide Bibliographic Reference DGGS Staff, 2014, Alaska Coastal Profile Tool (ACPT): Alaska

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Visitor, State of Alaska

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Skip to content State of Alaska myAlaska My Government Resident Business in Alaska Visiting Alaska State Employees State of Alaska Search Home Quick Links Departments Commissioners Employee Whitepages State Government Jobs Federal Jobs Starting a Small Business Living Get a Driver License Get a Hunting

Publications - AR 2010 | Alaska Division of Geological & Geophysical

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Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical DGGS AR 2010 Publication Details Title: Alaska Division of Geological & Geophysical Surveys Annual Report Authors: DGGS Staff Publication Date: Jan 2011 Publisher: Alaska Division of Geological &

NDE investigation of the timber foundation in the historic Kennecott Mine Concentration Mill Building

Treesearch

James P. Wacker; Xiping Wang; Douglas R. Rammer; Bessie M. Woodward

2011-01-01

The U.S. National Park Service acquired the National Historic Copper Mine at Kennecott, Alaska, in 1998. There was uncertainty about the condition of the timber-cribbing foundation supporting the concentration mill, the largest building in the mine complex. A comprehensive on-site evaluation of the timber cribbing foundation was performed in summer 2009. The inspection...

The challenges associated with developing science-based landscape scale management plans.

Treesearch

Robert C. Szaro; Douglas A. Jr. Boyce; Thomas Puchlerz

2005-01-01

Planning activities over large landscapes poses a complex of challenges when trying to balance the implementation of a conservation strategy while still allowing for a variety of consumptive and nonconsumptive uses. We examine a case in southeast Alaska to illustrate the breadth of these challenges and an approach to developing a science-based resource plan. Not only...

Red alder-conifer stands in Alaska: An example of mixed species management to enhance structural and biological complexity

Treesearch

Robert Deal; Ewa Orlikowska; David D’Amore; Paul Hennon

2017-01-01

There is worldwide interest in managing forests to improve biodiversity, enhance ecosystem services and assure long-term sustainability of forest resources. An increasingly important goal of forest management is to increase stand diversity and improve wildlife and aquatic habitat. Well-planned silvicultural systems containing a mixture of broadleaf-conifer species have...

Presentations - Lande, Lauren and others, 2015 | Alaska Division of

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Details Title: A petrological model for emplacement of the ultramafic Ni-Cu-PGE Alpha complex, eastern , Newberry, R.J., and Twelker, Evan, 2015, A petrological model for emplacement of the ultramafic Ni-Cu-PGE Sheets Maps & Other Oversized Sheets Sheet 1 A petrological model for emplacement of the ultramafic

75 FR 38454 - Fisheries of the Exclusive Economic Zone Off Alaska; Skates Management in the Bering Sea and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-02

... short- lived invertebrates (squids and octopuses) with long-lived fish (sharks and skates). If approved... occurring, and therefore the groundfish ACLs and AMs must be implemented by January 1, 2011. Skate, shark... BSAI. In the GOA, shark, sculpin, octopus, and squid groups are currently managed as a complex in the...

Epiguruk: a late Quaternary environmental record from northwestern Alaska

USGS Publications Warehouse

Hamilton, T.D.; Ashley, G.M.

1993-01-01

Epiguruk, a prominent bluff along the Kobuk River in northwestern Alaska, exposes a rich depositional record of Quaternary eolian and fluvial sand, with associated loess, paleosols, and periglacial features. Three major complexes of alluvial and eolian deposits are separated by two conspicuous organic-rich paleosols which formed during cool-moist interstadial intervals. Sediments between the two paleosols include eolian, channel, and floodplain deposits that formed during alluviation of the Kobuk River to a height of about 12m above the present level. The youngest depositional complex, which overlies the upper paleosol, is divisible into late Wisconsinan and Holocene components and into fluvial-channel, flood-plain, eolian-dune, sand-sheet, loess, and pond facies. Eolian sand from the active Kobuk sand sea overloaded the river during late Wisconsinan time, causing it to alluviate to about 13m above its modern level. The Holocene record reflects erosion and deposition by a small southern Tributary to the Kobuk River, downcutting by the Kobuk River toward its modern level, and subsequent erosion across a meander belt nearly 8km wide. 66 radiocarbon ages, many from rooted shrubs, provide a firm chronology for the past 35 k.y. at Epiguruk. -from Authors

Methane Emissions from the Inland Waters of Alaska

NASA Astrophysics Data System (ADS)

Striegl, R. G.; Butman, D. E.; Stackpoole, S. M.; Dornblaser, M.

2017-12-01

Inland waters at high latitudes generally emit methane (CH4) continuously to the atmosphere during the open water season and build-up CH4 under ice during winter that is released over a short period following ice melt. Landscape position, stream and river size, water source, and turbulence created by water flow largely control CH4 emissions from streams and rivers. Organic carbon sources for CH4 production in lakes vary widely among lakes and landscapes and include hydrologic inputs from terrestrial sources, releases from permafrost thaw (thermokarst), and autochthonous inputs from aquatic macrophytes and algae. Lake emissions are therefore controlled by the balance between within-lake CH4 production and consumption, surface turbulence at the water-air interface, and CH4 ebullition. This creates a complex range of conditions that are difficult to characterize, where dissolved CH4 concentrations may vary by up to 4 orders of magnitude among lakes and/or within a single lake over an annual seasonal cycle. Moreover, large inputs of organic matter from permafrost thaw or other sources commonly result in high rates of bubble production and ebullition from some lakes, while other lakes have negligible ebullition. We quantified water surface areas and estimated CH4 emission rates for lakes, streams and rivers for the six major hydrologic regions of Alaska and determined that they collectively emit about 0.124 Tg C per year as CH4 to the atmosphere. Lake emissions comprise about 75% of the total. When adjusted for total land surface area in Alaska, our lake emission estimate is substantially smaller than previous global estimates for inland waters north of 50 degrees North latitude. We attribute this to incorporation of results that cover a broad range of lake conditions in interior Alaska and to new data from lakes in southwest Alaska that have very low CH4 concentration but very large surface area.

Stable Isotope (δ13C, δ15N, δ34S) Analysis and Satellite Telemetry Depict the Complexity of Gray Wolf (Canis lupus) Diets in Southwest Alaska

NASA Astrophysics Data System (ADS)

Stanek, A.; Watts, D. E.; Cohn, B. R.; Spencer, P.; Mangipane, B.; Welker, J. M.

2010-12-01

Throughout Alaska, gray wolves (Canis lupus) are a top predator of large ungulates. While they primarily rely on ungulates such as moose (Alces alces) and caribou (Rangifer tarandus) as food, they are opportunistic and use alternative resources. The variation and supplemental protein sources in wolf diet has not been studied extensively on live animals currently using the landscape. With large seasonal influxes of Pacific salmon (Oncorhynchus sp.) into Alaska, terrestrial carnivore use of marine species is of particular interest. Using stable isotope (δ13C, δ15N, δ34S) analysis of wolf guard hair and blood, this study aims to determine the proportion of marine derived nutrients (MDN) in the diet of wolf packs within and surrounding Lake Clark National Park and Preserve and Alaska Peninsula and Becharof National Wildlife Refuges in Southwest Alaska. Satellite telemetry from the animals sampled facilitates quantification of landscape use patterns in correspondence with isotopic traits. Wolf pack territories within and surrounding the Lake Clark region appear to vary in spatial extent and in availability of MDN, such as salmon. Initial analysis shows that two packs with smaller home ranges, centrally located around areas with greater salmon availability, have enriched δ15N values compared to packs that have larger home ranges not centralized around salmon spawning waters. This pattern of isotopic enrichment is found in red blood cells, blood serum and hair, representing diets over different time scales. The enrichment in both blood and hair indicates a sustained use of MDN over the previous six to nine months. In the Lake Clark region, simple mixing model estimates suggest that up to 30% of wolf pack diets may be from marine sources. In contrast, packs with larger home ranges and less access to salmon have stable isotope values representative of a terrestrial diet.

Home, Alaska Oil and Gas Conservation Commission, State of Alaska

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PNNL researcher explores behavior of complex molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manke, Kristin L.

2007-11-19

From cold winters in St. Petersburg, Russia, to sweltering summers in southeastern Washington State, Dr. Julia Laskin’s career in science has been an interesting journey. Her latest trip landed her on the steps of the White House for a photo-op with the President. Laskin received the Presidential Early Career Award for Scientists and Engineers for her research on the fundamental aspects of the reaction kinetics and dynamics of activating and dissociating complex molecular ions. Her work at Pacific Northwest National Laboratory provides a basis for the development of analytical techniques for improved characterization of synthetic and natural polymers, petroleum, biofuelsmore » and other complex samples using mass spectrometry.« less

Publications - DDS 4 | Alaska Division of Geological & Geophysical Surveys

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Datasets of Alaska: Alaska Division of Geological & Geophysical Surveys Digital Data Series 4, http ; Alaska Statewide Maps; Alaska, State of; Digital Elevation Model; Digital Surface Model (DSM); Geologic

Satellite monitoring of remote volcanoes improves study efforts in Alaska

NASA Astrophysics Data System (ADS)

Dean, K.; Servilla, M.; Roach, A.; Foster, B.; Engle, K.

Satellite monitoring of remote volcanoes is greatly benefitting the Alaska Volcano Observatory (AVO), and last year's eruption of the Okmok Volcano in the Aleutian Islands is a good case in point. The facility was able to issue and refine warnings of the eruption and related activity quickly, something that could not have been done using conventional seismic surveillance techniques, since seismometers have not been installed at these locations.AVO monitors about 100 active volcanoes in the North Pacific (NOPAC) region, but only a handful are observed by costly and logistically complex conventional means. The region is remote and vast, about 5000 × 2500 km, extending from Alaska west to the Kamchatka Peninsula in Russia (Figure 1). Warnings are transmitted to local communities and airlines that might be endangered by eruptions. More than 70,000 passenger and cargo flights fly over the region annually, and airborne volcanic ash is a threat to them. Many remote eruptions have been detected shortly after the initial magmatic activity using satellite data, and eruption clouds have been tracked across air traffic routes. Within minutes after eruptions are detected, information is relayed to government agencies, private companies, and the general public using telephone, fax, and e-mail. Monitoring of volcanoes using satellite image data involves direct reception, real-time monitoring, and data analysis. Two satellite data receiving stations, located at the Geophysical Institute, University of Alaska Fairbanks (UAF), are capable of receiving data from the advanced very high resolution radiometer (AVHRR) on National Oceanic and Atmospheric Administration (NOAA) polar orbiting satellites and from synthetic aperture radar (SAR) equipped satellites.

Activity patterns and time budgets of the declining sea otter population at Amchitka Island, Alaska

USGS Publications Warehouse

Gelatt, Thomas S.; Siniff, Donald B.; Estes, James A.

2002-01-01

Time budgets of predators may reflect population status if time spent foraging varies with local prey abun- dance. We assumed that the sea otter (Enhydra lutris) population at Amchitka Island, Alaska, USA, had been at equilibrium since the early 1960s and collected time budgets of otters to be used to represent future conditions of currently expanding sea otter populations. We used radiotelemetry to monitor activity-time budgets of otters from August 1992 to March 1994. Sea otter activity was directly linked to sex, age, weather condition, season, and time of day. Sea otters differed in percent time foraging among cohorts but not within cohorts. Percent time foraging ranged from 21% for females with very young (≤ 3weeks of age) dependent pups to 52% for females with old (≥10 weeks of age) pups. Otters foraged more and hauled out more as local sea conditions worsened. Adult males spent less time foraging during winter and spring, consistent with seasonal changes in prey selection. Time spent for- aging was similar to that reported for otters in California and an established population in Prince William Sound, Alaska, but greater than that of otters in recently established populations in Oregon and Alaska. Despite current evidence indicating that the population was in decline during our study, we were unable to recognize this change using time budgets. Our results illustrate the importance of stratifying analyses of activity patterns by age and sex cohorts and the complexity inherent in comparisons of behavioral data between different populations relying on distinct prey bases.

Multidisciplinary Observations of Subduction (MOOS) Experiment in South-Central Alaska

NASA Astrophysics Data System (ADS)

Christensen, D.; Abers, G.; Freymueller, J.

2008-12-01

Seismic and geodetic data are being collected in the Kenai Peninsula and surrounding area of south central Alaska as part of the PASSCAL experiment MOOS. A total of 34 broadband seismic stations were deployed between the summers of 2007 and 2008. Seventeen of these stations continue to operate for an additional year and are scheduled to be removed in the summer of 2009. Numerous GPS campaign sites have and will be visited during the same time period. The MOOS seismic deployment provides coverage across the interplate coupled zone and adjacent transition zone in the shallow parts of the Alaskan subduction zone. It is a southern extension of an earlier broadband deployment BEAAR (Broadband Experiment Across the Alaska Range) to the north. When integrated with the previous BEAAR experiment, these data will allow high-resolution broadband imaging along a 600 km long transect over the Alaska subduction zone, at 10-15 km station spacing. The MOOS deployment allows us to test several hypotheses relating to the postulated subduction of the Yakutat Block and the nature of the coupled zone which ruptured in the great 1964 earthquake. The seismic and geodetic stations cover an area that includes part of the 1964 main asperity and the adjacent, less coupled, region to the southwest. Data gathered from this experiment will shed light on the nature of this boundary from both a geodetic and seismic (or earth structure) perspective. Shallow seismicity recorded by this network greatly improves the catalog of events in this area and helps to delineate active features in the subduction complex. Preliminary results from this project will be presented.

Detrital Zircon Geochronology of Cretaceous and Paleogene Strata Across the South-Central Alaskan Convergent Margin

USGS Publications Warehouse

Bradley, Dwight; Haeussler, Peter J.; O'Sullivan, Paul; Friedman, Rich; Till, Alison; Bradley, Dan; Trop, Jeff

2009-01-01

Ages of detrital zircons are reported from ten samples of Lower Cretaceous to Paleogene metasandstones and sandstones from the Chugach Mountains, Talkeetna Mountains, and western Alaska Range of south-central Alaska. Zircon ages are also reported from three igneous clasts from two conglomerates. The results bear on the regional geology, stratigraphy, tectonics, and mineral resource potential of the southern Alaska convergent margin. Chugach Mountains - The first detrital zircon data are reported here from the two main components of the Chugach accretionary complex - the inboard McHugh Complex and the outboard Valdez Group. Detrital zircons from sandstone and two conglomerate clasts of diorite were dated from the McHugh Complex near Anchorage. This now stands as the youngest known part of the McHugh Complex, with an inferred Turonian (Late Cretaceous) depositional age no older than 91-93 Ma. The zircon population has probability density peaks at 93 and 104 Ma and a smattering of Early Cretaceous and Jurassic grains, with nothing older than 191 Ma. The two diorite clasts yielded Jurassic U-Pb zircon ages of 179 and 181 Ma. Together, these findings suggest a Mesozoic arc as primary zircon source, the closest and most likely candidate being the Wrangellia composite terrane. The detrital zircon sample from the Valdez Group contains zircons as young as 69 and 77 Ma, consistent with the previously assigned Maastrichtian to Campanian (Late Cretaceous) depositional age. The zircon population has peaks at 78, 91, 148, and 163 Ma, minor peaks at 129, 177, 330, and 352 Ma, and no concordant zircons older than Devonian. A granite clast from a Valdez Group conglomerate yielded a Triassic U-Pb zircon age of 221 Ma. Like the McHugh Complex, the Valdez Group appears to have been derived almost entirely from Mesozoic arc sources, but a few Precambrian zircons are also present. Talkeetna Mountains - Detrital zircons ages were obtained from southernmost metasedimentary rocks of the Talkeetna Mountains (schist of Hatcher Pass) and, immediately to the south, the northernmost sedimentary sequence of the Matanuska forearc basin (Arkose Ridge Formation). Detrital zircons from the Paleogene Arkose Ridge Formation are as young as 61 and 70 Ma; the population is dominated by a single Late Cretaceous peak at 76 Ma; the oldest zircon is 181 Ma. Sedimentological evidence clearly shows that the conglomeratic Arkose Ridge Formation was derived from the Talkeetna Mountains; our detrital zircon data support this inference. Zircons dated at ca. 90 Ma in the Arkose Ridge sample suggest that buried or unmapped plutons of this age may exist in the Talkeetnas. This is a particularly interesting age as it corresponds to the age of the supergiant Pebble gold-molybdenum-copper porphyry prospect near Iliamna and suggests a new area of prospectivity for Pebble-type deposits. The schist of Hatcher Pass, which was previously assigned a Jurassic depositional age, yielded surprisingly young Late Cretaceous detrital zircons, the youngest at 75 Ma. The probability density curve has four Cretaceous peaks from 76 to 102 Ma, a pair of Late Jurassic peaks at 155 and 166 Ma, three Early Jurassic to Late Triassic peaks at 186, 197, and 213 Ma, minor Carboniferous peaks at 303 and 346 Ma, and a minor Paleoproterozoic peak at 1828 Ma. The schist of Hatcher Pass was largely derived from Mesozoic arc sources, most likely the Wrangellia composite terrane, with some contribution from one or more older, inboard sources, probably including the Yukon-Tanana terrane. We postulate that the schist of Hatcher Pass represents metamorphosed rocks of the Valdez Group that were subducted and then exhumed along the Chugach terrane's 'backstop' during Paleogene transtension. Western Alaska Range - Six detrital zircon samples were collected from a little studied belt of turbidites in Tyonek quadrangle on strike with the Kahiltna assemblage of the central Alaska Range. Many of the sandstones ar

Publications - NL 2002-1 | Alaska Division of Geological & Geophysical

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Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical 2002 Publisher: Alaska Division of Geological & Geophysical Surveys Ordering Info: Download below Reference DGGS Staff, and Werdon, M.B., 2002, Alaska GeoSurvey News - Geologic Investigations in the Salcha

76 FR 81247 - Fisheries of the Exclusive Economic Zone Off Alaska; Groundfish of the Gulf of Alaska; Amendment 88

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-27

... Atmospheric Administration 50 CFR Part 679 Fisheries of the Exclusive Economic Zone Off Alaska; Groundfish of... Exclusive Economic Zone Off Alaska; Groundfish of the Gulf of Alaska; Amendment 88 AGENCY: National Marine... conservation, management, safety, and economic gains realized under the Central Gulf of Alaska Rockfish Pilot...

Home - Gold mining in Alaska - Libraries, Archives, & Museums at Alaska

Science.gov Websites

State Library Skip to main content State of Alaska myAlaska Departments State Employees Statewide Links × Upcoming Holiday Closure for Memorial Day The Alaska State Libraries, Archives, & Tuesday, May 29. Department of Education and Early Development Alaska State Libraries, Archives, and

Publications - GMC 171 | Alaska Division of Geological & Geophysical

Science.gov Websites

Arco Alaska Inc. Delta State #2 well Authors: Pawlewicz, Mark Publication Date: 1990 Publisher: Alaska , Vitrinite reflectance data of cuttings (3270'-10760') from the Arco Alaska Inc. Delta State #2 well: Alaska

The Mobile Margin of (Far) North America: GPS Constraints on Active Deformation in Alaska and the Role of the Yakutat Block

NASA Astrophysics Data System (ADS)

Elliott, J.; Freymueller, J. T.; Larsen, C. F.; Motyka, R. J.

2010-12-01

GPS data from southern Alaska and the northern Canadian Cordillera have helped redefine the region’s tectonic landscape. Instead of a comparatively simple interaction between the Pacific and North American plates, with relative motion accommodated on a single boundary fault, we find a margin made up of a number of small blocks and deformation zones with relative motion distributed across a variety of structures. Much of this complexity can be attributed to the Yakutat block, an allochthonous terrane that has been colliding with southern Alaska since the Miocene. We present a GPS-derived tectonic model for the Yakutat block collision and its effects on southern Alaska and eastern Canada. The Yakutat block moves NNW at a rate of 50 mm/a, resulting in ~ 45 mm/a of NW-directed convergence with southern Alaska. Along its eastern edge, the Yakutat block is deforming, represented in our model by two small northwesterly moving blocks outboard of the Fairweather fault. Part of the strain from the collision is transferred east of the Fairweather - Queen Charlotte fault system, causing the region inboard of the Fairweather fault to undergo a distinct clockwise rotation into the northern Canadian Cordillera. Further south, the region directly east of the Queen Charlotte fault displays a much slower clockwise rotation, suggesting that it is at least partially pulled along by the northern block motion. About 5% of the relative motion is transferred even further east, causing small northeasterly motions well into the northern Cordillera. The northwestern edge of the Yakutat block marks the main deformation front between that block and southern Alaska. Multiple narrow, northwesterly moving blocks bounded by N- to NW-dipping thrust faults are required to explain the GPS data between the Malaspina Glacier and the Bagley Ice Valley. These “blocks” may be more aptly termed crustal slivers or deformation zones due to their size and because their bounding faults may sole out into a main thrust instead of cutting through the lithosphere. In contrast with the region to the east, relative convergence is accommodated over a fairly short distance across the St. Elias Mountains. West of the deformation front, the en echelon blocks and faults continue until the vicinity of the Bering Glacier, where the GPS data reveal a rotation towards the north as the tectonic regime transitions from the collision and accretion of the Yakutat block to subduction along the Aleutian Megathrust. North of the Chugach and St. Elias Ranges, the Southern Alaska block rotates counterclockwise.

Alaska Interagency Ecosystem Health Work Group

USGS Publications Warehouse

Shasby, Mark

2009-01-01

The Alaska Interagency Ecosystem Health Work Group is a community of practice that recognizes the interconnections between the health of ecosystems, wildlife, and humans and meets to facilitate the exchange of ideas, data, and research opportunities. Membership includes the Alaska Native Tribal Health Consortium, U.S. Geological Survey, Alaska Department of Environmental Conservation, Alaska Department of Health and Social Services, Centers for Disease Control and Prevention, U.S. Fish and Wildlife Service, Alaska Sea Life Center, U.S. Environmental Protection Agency, and Alaska Department of Fish and Game.

Publications - PIR 2008-1C | Alaska Division of Geological & Geophysical

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investigations in the Brooks Range Foothills and North Slope, Alaska: Alaska Division of Geological & Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska content DGGS PIR 2008-1C Publication Details Title: Evaluation of stratigraphic continuity between the

Publications - RI 2015-7 | Alaska Division of Geological & Geophysical

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Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska content DGGS RI 2015-7 Publication Details Title: Surficial geology of the Tyonek area, south-central of the Tyonek area, south-central Tyonek Quadrangle, Alaska: Alaska Division of Geological &

Publications - PIR 2008-1A | Alaska Division of Geological & Geophysical

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of recent geologic field investigations in the Brooks Range Foothills and North Slope, Alaska: Alaska Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska ; Tectonics; Thermal History; Thrust; Toolik River; Torok Formation; Turbidites; Turonian; Valanginian Top of