Science.gov

Sample records for paleoclimatology

  1. Molecular proxies for paleoclimatology

    NASA Astrophysics Data System (ADS)

    Eglinton, Timothy I.; Eglinton, Geoffrey

    2008-10-01

    We summarize the applications of molecular proxies in paleoclimatology. Marine molecular records especially are proving to be of value but certain environmentally persistent compounds can also be measured in lake sediments, loess deposits and ice cores. The fundamentals of this approach are the molecular parameters, the compound abundances and carbon, hydrogen, nitrogen and oxygen isotopic contents which can be derived by the analysis of sediment extracts. These afford proxy measures which can be interpreted in terms of the conditions which control climate and also reflect its operation. We discuss two types of proxy; those of terrigenous and those of aquatic origin, and exemplify their application in the study of marine sediments through the medium of ten case studies based in the Atlantic, Mediterranean and Pacific Oceans, and in Antarctica. The studies are mainly for periods in the present, the Holocene and particularly the last glacial/interglacial, but they also include one study from the Cretaceous. The terrigenous proxies, which are measures of continental vegetation, are based on higher plant leaf wax compounds, i.e. long-chain (circa C 30) hydrocarbons, alcohols and acids. They register the relative contributions of C 3 vs. C 4 type plants to the vegetation in the source areas. The two marine proxies are measures of sea surface temperatures (SST). The longer established one, (U 37K') is based on the relative abundances of C 37 alkenones photosynthesized by unicellular algae, members of the Haptophyta. The newest proxy (TEX 86) is based on C 86 glycerol tetraethers (GDGTs) synthesized in the water column by some of the archaeal microbiota, the Crenarchaeota.

  2. Paleoclimatology

    SciTech Connect

    Not Available

    1991-01-01

    This book presents information that helps scientists to understand climate changes of the past. The book focuses on the results from observational modeling studies from the Quaternary and pre-Quaternary periods. The text includes sections on climate models and their structures, power, and limitations; the need for additional research, and the consequences of greenhouse warming. The book is 18th in the Oxford Monographs on Geology and Geophysics series.

  3. Milestones and Lacunae in Quaternary Paleoclimatology

    NASA Astrophysics Data System (ADS)

    Bradley, R. S.

    2008-12-01

    It has been just over 40 years since Nick Shackleton submitted his PhD thesis on, 'The Measurement of Palaeotemperatures in the Quaternary Era'. Only a few years earlier, Libby was awarded the Nobel Prize for his work on radiocarbon dating. Looking back, we recognize that these were seminal events which provided essential insight and tools for generations of future researchers, opening the window to our interpretation of the earth's recent history. Research in paleoclimatology and paleoceanography has made enormous advances since these early steps were taken, and our understanding of how climates have changed, and why, has exploded. Hardly a week goes by without a new and interesting record or model simulation being published. Yet gaps remain, and new questions continue to emerge. New analytical techniques provide higher and higher resolution data sets, yet chronology remains a challenge in many records. This is especially important in deciphering times of abrupt change in earth history, when the synchronism of geographically dispersed events (or lack thereof) is of critical importance. The role of abrupt climate change in driving societal change is also controversial. Certainly there is evidence from many regions for abrupt, unprecedented and persistent climate anomalies for which we commonly have no explanation, and such episodes appear to have had significant effects of societies in the past. Deciphering the causes of such episodes, and how they affected societies has important implications for our understanding of the past and the future. Understanding the role of forcing and feedbacks is also essential. For example, many questions remain about the role of solar forcing. If small changes in solar irradiance have driven climate changes (as many have argued) large feedbacks must be involved. Modelling may help in resolving such questions. Many new proxies have been developed, though often our understanding of how these relate to climate is rudimentary at best. In

  4. The Urbino Summer School in Paleoclimatology: Investing in the future of paleoclimatology

    NASA Astrophysics Data System (ADS)

    Schellenberg, S. A.; Galeotti, S.; Brinkhuis, H.; Leckie, R. M.

    2010-12-01

    Improving our understanding of global climate dynamics is increasingly critical as we continue to perturb the Earth system on geologically rapid time-scales. One approach is the modeling of climate dynamics; another is the exploitation of natural archives of climate history. To promote the synergistic integration of these approaches in the next generation of paleoclimatologists, a group of international teacher-scholars have developed the Urbino Summer School in Paleoclimatology (USSP), which has been offered since 2004 at the Università degli Studi di Urbino in Urbino, Italy. The USSP provides international graduate students with an intensive three-week experience in reconstructing the history and dynamics of climate through an integrated series of lectures, investigations, and field and laboratory analyses. Complementing these formal components, informal scientific discussions and collaborations are promoted among faculty and students through group meals, coffee breaks, socials, and evening presentations. The first week begins with a broad overview of climate history and dynamics, and then focuses on the principles and methods that transform geographically- and materially-diverse data into globally time-ordinated paleoclimatic information. Lectures largely serve as “connective tissue” for student-centered investigations that use ocean drilling data and student-collected field data from the spectacular exposures of the surrounding Umbre-Marche Basin. The second week provides sessions and investigations on various biotic and geochemical proxies, and marks the start of student “working groups,” each of whom focus on current understanding of, and outstanding questions regarding, a particular geologic time-interval. Parallel sessions also commence, wherein students self-select to attend one of three concurrently-offered more specialized topics. The third week is an intensive exploration of geochemical, climate, and ocean modeling that stresses the integration

  5. Methods and future directions for paleoclimatology in the Maya Lowlands

    NASA Astrophysics Data System (ADS)

    Douglas, Peter M. J.; Brenner, Mark; Curtis, Jason H.

    2016-03-01

    A growing body of paleoclimate data indicates that periods of severe drought affected the Maya Lowlands of southeastern Mexico and northern Central America, especially during the Terminal Classic period (ca. 800-950 CE), raising the possibility that climate change contributed to the widespread collapse of many Maya polities at that time. A broad range of paleoclimate proxy methods have been applied in the Maya Lowlands and the data derived from these methods are sometimes challenging for archeologists and other non-specialists to interpret. This paper reviews the principal methods used for paleoclimate inference in the region and the rationale for climate proxy interpretation to help researchers working in the Maya Lowlands make sense of paleoclimate datasets. In particular, we focus on analyses of speleothems and lake sediment cores. These two paleoclimate archives have been most widely applied in the Maya Lowlands and have the greatest potential to provide insights into climate change impacts on the ancient Maya. We discuss the development of chronologies for these climate archives, the proxies for past climate change found within them, and how these proxy variables are interpreted. Finally, we present strategies for improving our understanding of proxy paleoclimate data from the Maya Lowlands, including multi-proxy analyses, assessment of spatial variability in past climate change, combined analysis of climate models and proxy data, and the integration of paleoclimatology and archeology.

  6. Geology, paleoclimatology and the evolution of the kidney: some explorations into the legacy of Homer Smith.

    PubMed

    Kooman, Jeroen P

    2012-01-01

    The aim of this review is to perform an overview of the relation between kidney development in different species and new developments in plate tectonics and paleoclimatology, which likely had a remarkable effect on evolution. The review follows the ideas of Homer Smith, but adds new data on the subjects which were unknown in Homer Smith's time. The structure and function of the kidney are a result of hundreds of millions of years of evolution, in which adaptations had to be made in response to environmental demands while maintaining the kidney's integrated function. The ideas of Homer Smith have greatly contributed to our understanding of this process, and continue to be of relevance both for researchers as well as physicians working in the field of kidney disease. PMID:22572704

  7. Marine tephra in the Japan Sea sediments as a tool for paleoceanography and paleoclimatology

    NASA Astrophysics Data System (ADS)

    Ikehara, Ken

    2015-12-01

    Tephra is a product of large and explosive volcanic events and can travel thousands of kilometers before deposition. Consequently, tephra deposits are common in terrestrial, lacustrine, marine, and glacial environments. Because tephra deposition is a geologically synchronous event, tephras constitute important isochrones in the Quaternary sequence, not only in Japan but also throughout the northwest Pacific and its marginal seas. As a result, establishing the chronostratigraphic order of tephra deposits is an effective tool for assessing local and regional stratigraphies and for correlating events among sites. For example, tephrostratigraphy can provide precise chronological constraints for other stratigraphic data, such as magneto- and biostratigraphic data. Spatiotemporal variability in the occurrence and geochemistry of tephras can also be used to trace the magmatic evolution of island arcs and their relationships to regional tectonics. In a paleoclimatic context, tephra deposits allow the correlation of past climate events among terrestrial, lacustrine, and marine environments. Tephrochronology is also a fundamental element used in reconstructing the marine reservoir effect, where the ages of tephra in marine and terrestrial settings are compared. Therefore, tephra is a valuable tool not only in stratigraphy, chronology, and volcanology but also in paleoceanography and paleoclimatology.

  8. Impact of maximum borehole depths on inverted temperature histories in borehole paleoclimatology

    NASA Astrophysics Data System (ADS)

    Beltrami, H.; Smerdon, J. E.; Matharoo, G. S.; Nickerson, N.

    2011-02-01

    A quantitative assessment is presented for the impact of the maximum depth of a temperature-depth profile on the estimate of the climatic transient and the resultant ground surface temperature (GST) reconstruction used in borehole paleoclimatology. The depth of the profile is important because the downwelling climatic signal must be separated from the quasi-steady state thermal regime established by the energy in the Earth's interior. This component of the signal is estimated as a linear increase in temperature with depth from the lower section of a borehole temperature profile, which is assumed to be unperturbed by recent changes in climate at the surface. The validity of this assumption is dependent on both the subsurface thermophysical properties and the character of the downwelling climatic signal. Such uncertainties can significantly impact the determination of the quasi-steady state thermal regime, and consequently the magnitude of the temperature anomaly interpreted as a climatic signal. The quantitative effects and uncertainties that arise from the analysis of temperature-depth profiles of different depths are presented. Results demonstrate that widely different GST histories can be derived from a single temperature profile truncated at different depths. Borehole temperature measurements approaching 500-600 m depths are shown to provide the most robust GST reconstructions spanning 500 to 1000 ybp. It is further shown that the bias introduced by a temperature profile of depths shallower than 500-600 m remains even if the time span of the reconstruction target is shortened.

  9. Impact of maximum borehole depths on inverted temperature histories in borehole paleoclimatology

    NASA Astrophysics Data System (ADS)

    Beltrami, H.; Smerdon, J. E.; Matharoo, G. S.; Nickerson, N.

    2011-07-01

    A quantitative assessment is presented for the impact of the maximum depth of a temperature-depth profile on the estimate of the climatic transient and the resultant ground surface temperature (GST) reconstruction used in borehole paleoclimatology. The depth of the profile is important because the downwelling climatic signal must be separated from the quasi-steady state thermal regime established by the energy in the Earth's interior. This component of the signal is estimated as a linear increase in temperature with depth from the lower section of a borehole temperature profile, which is assumed to be unperturbed by recent changes in climate at the surface. The validity of this assumption is dependent on both the subsurface thermophysical properties and the character of the downwelling climatic signal. Such uncertainties can significantly impact the determination of the quasi-steady state thermal regime, and consequently the magnitude of the temperature anomaly interpreted as a climatic signal. The quantitative effects and uncertainties that arise from the analysis of temperature-depth profiles of different depths are presented. Results demonstrate that widely different GST histories can be derived from a single temperature profile truncated at different depths. Borehole temperature measurements approaching 500-600 m depths are shown to provide the most robust GST reconstructions spanning 500 to 1000 yr BP. It is further shown that the bias introduced by a temperature profile of depths shallower than 500-600 m remains even if the time span of the reconstruction target is shortened.

  10. Technical note: The Linked Paleo Data framework - a common tongue for paleoclimatology

    NASA Astrophysics Data System (ADS)

    McKay, Nicholas P.; Emile-Geay, Julien

    2016-04-01

    Paleoclimatology is a highly collaborative scientific endeavor, increasingly reliant on online databases for data sharing. Yet there is currently no universal way to describe, store and share paleoclimate data: in other words, no standard. Data standards are often regarded by scientists as mere technicalities, though they underlie much scientific and technological innovation, as well as facilitating collaborations between research groups. In this article, we propose a preliminary data standard for paleoclimate data, general enough to accommodate all the archive and measurement types encountered in a large international collaboration (PAGES 2k). We also introduce a vehicle for such structured data (Linked Paleo Data, or LiPD), leveraging recent advances in knowledge representation (Linked Open Data).The LiPD framework enables quick querying and extraction, and we expect that it will facilitate the writing of open-source community codes to access, analyze, model and visualize paleoclimate observations. We welcome community feedback on this standard, and encourage paleoclimatologists to experiment with the format for their own purposes.

  11. Technical Note: The Linked Paleo Data framework - a common tongue for paleoclimatology

    NASA Astrophysics Data System (ADS)

    McKay, N. P.; Emile-Geay, J.

    2015-09-01

    Paleoclimatology is a highly collaborative scientific endeavor, increasingly reliant on online databases for data sharing. Yet, there is currently no universal way to describe, store and share paleoclimate data: in other words, no standard. Data standards are often regarded by scientists as mere technicalities, though they underlie much scientific and technological innovation, as well as facilitating collaborations between research groups. In this article, we propose a preliminary data standard for paleoclimate data, general enough to accommodate all the proxy and measurement types encountered in a large international collaboration (PAGES2K). We also introduce a vehicle for such structured data (Linked Paleo Data, or LiPD), leveraging recent advances in knowledge representations (Linked Open Data). The LiPD framework enables quick querying and extraction, and we expect that it will facilitate the writing of open-source, community codes to access, analyze, model and visualize paleoclimate observations. We welcome community feedback on this standard, and encourage paleoclimatologists to experiment with the format for their own purposes.

  12. Paleoclimatological implications of Mid-Cretaceous paleosol sphaerosiderites from 70 degrees paleonorth, central Spitsbergen

    NASA Astrophysics Data System (ADS)

    White, T.

    2010-12-01

    Paleoclimatological reconstructions of Mid-Cretaceous greenhouse atmospheric hydrology have been accomplished using a model-data comparison approach based on a stable isotopic tracer version of the GENESIS GCM benchmarked using oxygen isotopic data obtained from paleosol sphaerosiderites. While ample data coverage exists for much of mid-latitude North America, the paleo Arctic realm has thus far been represented by data only from the North Slope, Alaska. The new data presented here provides an additional paleo Arctic data point from central Spitsbergen. Mid-Cretaceous paleosol sphaerosiderites were identified in cores that penetrated the uppermost portions of the Aptian-Cenomanian (?) Carolinefjellet Formation of the Adventdalen Group - the upper age limit of the Carolinefjellet Formation in central Spitsbergen remains undefined near the Albian-Cenomanian boundary. Notably, on the Barents Shelf to the south the coeval Kolmule Formation of the Adventdalen Group is known to range in age into the lower Cenomanian suggesting the possibility that the Carolinefjellet Formation may also contain the Albian-Cenomanian boundary. Seven distinct sphaerosiderite-bearing horizons were identified within a 2.5 meter interval of dominantly light to medium gray siltstone and fine sandstone overlain by dark gray siltstone and black carbonaceous shale. The samples were microdrilled for stable carbon and oxygen isotopic analysis. Sphaerosiderite oxygen isotope values range from -11.6 per mil to -7.9 per mil. A comparison of this data with an Albian-Cenomanian North American data set indicates that amplified paleoatmospheric hydrologic processes are not required to adequately model the Mid-Cretaceous greenhouse atmosphere. The data is further compared and contrasted to similar data for the Paleocene-Eocene boundary to substantiate this conclusion.

  13. The Earth's Record of Climate: A focused-topic introductory course in paleoclimatology

    NASA Astrophysics Data System (ADS)

    Theissen, K. M.

    2006-12-01

    In the department of geology at The University of St. Thomas (UST), faculty members have developed several introductory courses that focus on specific topics of interest to students while at the same time providing a core set of agreed-upon concepts that are critical for all students. I have developed an introductory course that explores the science of paleoclimatology and its relevance to studies of modern global climatic change. Although many geology departments offer a course on climatic change, very few are taught as an entry-level course that is accessible to non-majors. In part, this is because the focus on climate is something of a departure from the curriculum model followed in more traditional introductory geology courses. I have designed and taught this course with the overarching goal that by the end of the course students should be able to analyze and interpret a variety of datasets to make a thorough paleoclimatic reconstruction that comprises their final project. With this goal in mind, I use a combination of classroom exercises, homework, and laboratory activities that help the students to build the necessary skills by working with different forms of earth science data including oxygen isotopic data, and pollen, fossil, and sediment descriptions from lake cores. The course also has a strong emphasis on the interactions between earth systems and human influences that shape the climate system. Student assessment of the course over three years suggests that it both challenges them and increases their interest in earth science. Additionally, student evaluations of this course are higher than those for a more traditional physical geology course that I teach to a similar group.

  14. Paleoceanography and Paleoclimatology of the Southern Ocean: A Synthesis of Three Decades of Scientific Ocean Drilling

    NASA Astrophysics Data System (ADS)

    Warnke, D. A.; Filippelli, G.; Flores, J.; Marchitto, T. M.

    2004-12-01

    A Workshop on " Paleoceanography and Paleoclimatology of the Southern Ocean: A Synthesis of Three Decades of Scientific Ocean Drilling" Jan. 21-23, 2005 Boulder, CO Co-Convenors: D. Warnke, G. Filippelli, J.-A. Flores, T. Marchitto One of the greatest successes of the Ocean Drilling Program has been the concerted drilling efforts and exciting results recovered from the Southern Ocean (SO), which has been the focus of ten DSDP/ODP drilling legs. The SO is a critical component in the development and persistence of Antarctic glaciation, is a sensitive mixing pool of global water masses, a locus of high biological sedimentation, and contains high resolution records of climate forcing and response. As such, it is one of the most important oceanographic regions in the world. It is now an important time to mine the rich results from scientific ocean drilling over the past several decades and develop a scientific framework for future ocean drilling in this region. The focus of this Synthesis Workshop will be on the biogeochemical history of the SO, including: · Productivity proxies, rates, records, variations, and role of climate · Sedimentary records of organic carbon, calcium, silica, nutrients, and biogenic proxies: The role of the SO as a biogeochemical sink · Development and dynamics of the APFZ · Thermal structure and evolution of the SO · The role of limiting nutrients The overall goal to integrate the various proxies into a coherent paleoceanographic picture. Such a goal will help to synthesize several decades of scientific ocean drilling in the SO, and will likely bring to the forefront the as-yet-unanswered questions about the biogeochemical history of this important oceanic system. With this goal in mind, workshop participants will submit of a short (~250 word) abstract as the Workshop application, commit to presenting a poster at the workshop based on this abstract, and contribute to one or more manuscripts that will be published after the workshop, likely

  15. Borehole Paleoclimatology: In search of a minimum depth criterion for terrestrial borehole temperature profiles

    NASA Astrophysics Data System (ADS)

    Beltrami, H.; Smerdon, J. E.; Matharoo, G.; Nickerson, N. R.

    2010-12-01

    One important uncertainty in borehole paleoclimatology that has been overlooked is the degree to which ground surface temperature (GST) reconstructions depend on the maximum depth of the profile. Because the vast majority of measured borehole temperature profiles are acquired from boreholes of opportunity, the maximum measurement depth in data used for paleoclimatic studies varies considerably (beginning at depths as shallow as 100-150 m and extending to depths of more than 1 km). The depth of the borehole is important because the downwelling climatic signal must be separated from the quasi-steady state thermal regime established by the energy in the Earth's interior. This component of the signal is estimated as a linear increase in temperature with depth from the lower section of a borehole temperature profile, which is assumed to be unperturbed by recent changes in climate at the surface. The validity of this assumption is dependent on both the subsurface thermophysical properties and the character of the downwelling climatic signal. Such uncertainties can significantly impact the determination of the quasi-steady state thermal regime, and consequently the magnitude of the temperature anomaly interpreted as a climatic signal. Here we illustrate how the minimum depth of a temperature-depth profile impacts the estimation of the climatic transient and the resultant GST reconstruction. In particular, we attempt to quantitatively illustrate the effects and uncertainties that arise from the analysis of borehole temperature logs of different depths. Our results demonstrate that widely different GST histories can be derived from a single temperature profile truncated at different depths. We show that borehole temperature measurements approaching 500-600 m depths provide the most robust GST reconstructions and are preferable for inferring past climatic variations at the ground surface. Furthermore, we find that the bias introduced by a temperature profile of depths

  16. Gulf of Alaska Holocene paleoceanography and paleoclimatology from diatom proxies in core EW0408-22JC, Crawfish Inlet, Baranof Island, Alaska.

    NASA Astrophysics Data System (ADS)

    Loofbourrow, C.; Addison, J. A.; Hemphill-Haley, E.

    2014-12-01

    Diatom ecology is used in this study as a paleoceanographic and paleoclimatic proxy for the Eastern Gulf of Alaska. Core EW0408-22JC, an 11.84 m long piston core, was retrieved in 2004 from 188 m water depth in Crawfish Inlet, a deglaciated fjord of Baranof Island, Southeast Alaska, which opens to the eastern Gulf of Alaska (GOA). The core contains a nearly complete Holocene record constrained by 14C and tephrochronology with relatively high sedimentation rates of ~100-200 cm/ky, favorable to high-resolution climate investigations. High-resolution geochemical measurements indicate increasing opal and total organic concentrations and decreasing lithic and CaCO3 concentrations from early to late Holocene. Diatom ecology is quantified by counting of diatom taxa at approximately 170-year stratigraphic intervals, and evaluated for climatic and oceanographic significance using the modern analog technique (MAT) and factor analysis. Diatom proxy variability from this site is inferred to result from changes within the GOA climatic and oceanographic regime. Within this region, the strength and positioning of the Aleutian Low and the Alaska Current influence oceanographic parameters including sea surface temperature, downwelling, and nutrient availability, all of which are reflected in diatom ecology fluctuations. The adjacent North American terrestrial hydroclimate is largely controlled by these factors, and its past conditions are inferred by this reconstruction of GOA paleoceanography and paleoclimatology.

  17. Toward a semantic web of paleoclimatology

    NASA Astrophysics Data System (ADS)

    Emile-Geay, Julien; Eshleman, Jason A.

    2013-02-01

    Abstract The paleoclimate record is information-rich, yet significant technical barriers currently exist before this record can be used to answer scientific questions. Here we make the case for a universal format to structure paleoclimate data. A simple example demonstrates the scientific utility of such a self-describing way of organizing coral data and meta-data. This example is generalized to a universal ontology that may form the backbone of an open-source, open-access, and crowd-sourced paleoclimate database. The format is designed to enable semantic searches, and is expected to accelerate discovery on topical scientific problems like climate extremes, the characteristics of natural climate variability, and climate sensitivity to various forcings.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMPP21B2022E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMPP21B2022E"><span id="translatedtitle">Towards a semantic web of <span class="hlt">paleoclimatology</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Emile-Geay, J.; Eshleman, J. A.</p> <p>2012-12-01</p> <p>The paleoclimate record is information-rich, yet signifiant technical barriers currently exist before it can be used to automatically answer scientific questions. Here we make the case for a universal format to structure paleoclimate data. A simple example demonstrates the scientific utility of such a self-contained way of organizing coral data and meta-data in the Matlab language. This example is generalized to a universal ontology that may form the backbone of an open-source, open-access and crowd-sourced paleoclimate database. Its key attributes are: 1. Parsability: the format is self-contained (hence machine-readable), and would therefore enable a semantic web of paleoclimate information. 2. Universality: the format is platform-independent (readable on all computer and operating systems), and language- independent (readable in major programming languages) 3. Extensibility: the format requires a minimum set of fields to appropriately define a paleoclimate record, but allows for the database to grow organically as more records are added, or - equally important - as more metadata are added to existing records. 4. Citability: The format enables the automatic citation of peer- reviewed articles as well as data citations whenever a data record is being used for analysis, making due recognition of scientific work an automatic part and foundational principle of paleoclimate data analysis. 5. Ergonomy: The format will be easy to use, update and manage. This structure is designed to enable semantic searches, and is expected to help accelerate discovery in all workflows where paleoclimate data are being used. Practical steps towards the implementation of such a system at the community level are then discussed.; Preliminary ontology describing relationships between the data and meta-data fields of the Nurhati et al. [2011] climate record. Several fields are viewed as instances of larger classes (ProxyClass,Site,Reference), which would allow computers to perform operations on all records within a specific class (e.g. if the measurement type is δ18O , or if the proxy class is 'Tree Ring Width', or if the resolution is less than 3 months, etc). All records in such a database would be bound to each other by similar links, allowing machines to automatically process any form of query involving existing information. Such a design would also allow growth, by adding records and/or additional information about each record.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70011741','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70011741"><span id="translatedtitle">Late Miocene biogeography and <span class="hlt">paleoclimatology</span> of the central North Atlantic</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Poore, R.Z.</p> <p>1981-01-01</p> <p>Quantitative analyses of planktonic foraminiferal assemblages from Deep Sea Drilling Project (DSDP) Holes 334 and 410 demonstrate that subpolar and subtropical faunal provinces existed in the North Atlantic during the late Miocene. Climatic oscillations are clearly recorded in Hole 410 by variations in abundance of the Neogloboquadrina subpolar assemblage. These climatic oscillations have a period of about 1 m.y. Higher frequency oscillations with a periodicity of one to several hundred thousand years are evident from about 6.5 to 7.5 m.y. and are probably present throughout the entire late Miocene. A revised age of 7.0 m.y. is proposed for the first occurrence of the calcareous nannofossil Amaurolithus primus (the Amaurolithus datum). ?? 1981.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/631157','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/631157"><span id="translatedtitle">[<span class="hlt">Paleoclimatology</span> studies for Yucca Mountain site characterization]. Final report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p></p> <p>1996-05-03</p> <p>This report consists of two separate papers: Fernley Basin studies; and Influence of sediment supply and climate change on late Quaternary eolian accumulation patterns in the Mojave Desert. The first study involved geologic mapping of late Quaternary sediments and lacustrine features combined with precise control of elevations and descriptions of sediments for each of the major sedimentary units. The second paper documents the response of a major eolian sediment transport system in the east-central Mojave Desert: that which feeds the Kelso Dune field. Information from geomorphic, stratigraphic, and sedimentologic studies of eolian deposits and landforms is combined with luminescence dating of these deposits to develop a chronology of periods of eolian deposition. Both studies are related to site characterization studies of Yucca Mountain and the forecasting of rainfall patterns possible for the high-level radioactive waste repository lifetime.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li class="active"><span>1</span></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_1 --> <div id="page_2" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active"><span>2</span></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="21"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/128243','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/128243"><span id="translatedtitle"><span class="hlt">Paleoclimatology</span>. (Latest citations from the NTIS bibliographic database). Published Search</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p></p> <p>1995-07-01</p> <p>The bibliography contains citations concerning studies of climate in the geologic past. Glacial deposits, fossils, and paleogeographical data are reviewed. Topics include geologic formations, sediments and ocean bottom sampling, geological age determination, climatic changes, and greenhouse effects. (Contains 50-250 citations and includes a subject term index and title list.)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/476668','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/476668"><span id="translatedtitle"><span class="hlt">Paleoclimatology</span>: Second clock supports orbital pacing of the ice ages</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kerr, R.A.</p> <p>1997-05-02</p> <p>For a while, it looked as if a water-filled crack in the Nevada desert might doom the accepted explanation of the ice ages. Twenty years ago, the so-called astronomical theory had carried the day. Oceanographers had found evidence implying that the march of ice ages over the last million years was paced by the cyclical stretching and squeezing of Earth`s orbit around the sun, which would have altered the way sunlight fell on the planet`s surface. But in 1988, researchers scuba diving in Nevada`s Devils Hole came up with a climate record--captured in carbonate deposits in the crack-that seemed to contradict this chronology. This article discusses the findings and the puzzles that still remain. The records of sea-level change in Barbados coral appear to be right and the astronomical theory is on solid ground using a new clock based on the radioactive decay of uranium-235 to protactinium-231. However, the Devils Hole record also seems to be correct.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.7819D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.7819D"><span id="translatedtitle">Recrystallization-induced oxygen isotope changes in inclusion-hosted water of speleothems - <span class="hlt">paleoclimatological</span> implications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Demény, Attila; Czuppon, György; Leél-Őssy, Szabolcs; Németh, Péter; Szabó, Máté; Tóth, Mária; Németh, Tibor</p> <p>2016-04-01</p> <p>Stable hydrogen and oxygen isotope data of water trapped in fluid inclusions were collected for recently forming stalagmites and flowstones in order to determine how dripwater compositions are reflected and preserved in the inclusion water compositions. The samples were collected from different cave sites (with temperatures around 10 ± 1 °C) from the central and north-eastern parts of Hungary. Hydrogen isotope compositions were found to reflect dripwater values, whereas the oxygen isotope data were increasingly shifted from the local dripwater compositions with the time elapsed after deposition. The δ18O data are correlated with X-Ray diffraction full width at half maximum values (related to crystal domain size and lattice strain), suggesting that the oxygen isotope shift is related to recrystallization of calcite. Transmission electron microscope analyses detected the presence of nanocrystalline (<50 nm) calcite, whose crystallization to coarser-grained calcite crystals (>200 nm) may have induced re-equilibration between the carbonate and the trapped inclusion water. Additional data indicated that amorphous calcium carbonate (ACC) may have formed as a precursor of nanocrystalline calcite. ACC-calcite transformation followed by Ostwald ripening process provides an explanation for unexpectedly low oxygen isotope compositions in the inclusion water, especially in cold caves where carbonate may form first as an amorphous phase. This research was supported by the National Office for Research and Technology of Hungary (GVOP-3.2.1-2004-04-0235/3.0), the Hungarian Scientific Research Fund (OTKA CK 80661 and OTKA NK 101664).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMPP31C1150A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMPP31C1150A"><span id="translatedtitle">Central Asian <span class="hlt">Paleoclimatology</span> (Lake Karakul, Pamir) of the last 30,000 Years</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aichner, B.; Mischke, S.; Feakins, S. J.; Heinecke, L.; Rajabov, I.</p> <p>2014-12-01</p> <p>The goal of this study is to deepen the understanding of past changes in Central Asia, a climate sensitive region located at the intercept of large scale atmospheric circulation systems of which no pre-Holocene records exist so far. A ca. 10 m sediment core with a basal age of ca. 30 ka BP was drilled at Lake Karakul (Tajikistan), a large closed brackish lake situated in a tectonic basin at an altitude of 3,928 m. The lake catchment may be classified as alpine steppe to alpine desert with mean annual temperature and precipitation of ca. -3.9 °C and 82 mm, respectively. We applied a multi-proxy approach which combines inorganic and organic geochemical parameters. δ13C and δ18O values of authigenic carbonates show comparable trends with two pronounced episodes of depleted values at ca. 17.5 ka BP and 24 ka BP. These are indicative for fluctuations within the hydrological cycle and periods of low primary productivity which could have occurred synchronous to Northern Hemispheric climate events H1 and H2. Total organic carbon contents and organic biomarker concentrations are low during the glacial and rapidly increase to Holocene levels between ca. 14 and 11 ka BP. Biomarker fingerprints of aliphatic compounds are mostly dominated by mid-chain n-alkanes with δ13C values up to -14‰ which suggest a primarily aquatic origin. Terrestrial long-chain n-alkanes are mainly abundant during the late glacial to Holocene transition, possibly introduced by enhanced meltwater input during deglaciation. Their hydrogen isotopic variability is ca. 50‰ with constant depletion from ca. 19 to 10 ka BP. This is reflected by generally higher average δD values of aquatic n-alkanes throughout the glacial compared to Holocene values. Effective moisture variations alone cannot explain this offset. We suggest that changes in atmospheric circulation dynamics, origin of water vapour and source water for lipid synthesis (i.e. meltwater vs. precipitation) are the reasons for the observed isotopic shift at the late glacial to Holocene transition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6711595','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6711595"><span id="translatedtitle">Paleoecology and <span class="hlt">paleoclimatology</span> of a late holocene peat deposit from Braendevinsskaer, Central West Greenland</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bennike, O. )</p> <p>1992-08-01</p> <p>The macroscopical plant and animal remains of a nearshore peat deposit in West Greenland are described and documented. The assemblages contain a mixture of limnic, terrestrial, and marine plants and animals. These are divided into four local macrofossil assemblage zones, of which zone 3, ca. A.D. 950 to ca. A.D. 1760, represents a wet phase which is correlated in part with the Little Ice Age.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.5020J&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.5020J&link_type=ABSTRACT"><span id="translatedtitle">Evolution of the Ishtmus of Panama: biological, paleoceanographic, and <span class="hlt">paleoclimatological</span> implications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jaramillo, Carlos</p> <p>2016-04-01</p> <p>The rise of the Isthmus of Panama has been the product of small-scale geological processes that, however, have had worldwide repercussions. Four major events have been linked to the rise of the Isthmus including 1) the onset of the Thermohaline circulation (TCH), 2) the onset of Northern Hemisphere Glaciation, 3) the birth of the Caribbean Sea, and 4) the Great American Biotic Interchange (GABI). The available evidence indicates that there is a strong link between the closure of Central American Seaway (CAS) and the onset of Atlantic Meridional Overturning Circulation (a precursor of THC), but at 10 Ma rather than at 3.5 Ma as it was assumed before. There are not evidences of a connection between the full emergence of the Isthmus at 3.5 Ma and the onset of the NHG. There are strong evidences that the full emergence of the Isthmus at 3.5 Ma changed the oceanography of the Caribbean Sea to its modern conditions, although the role of additional variables into Pleistocene Caribbean Sea conditions still need to be evaluated, including the changes in the climate of the Pleistocene and the cessation of the freshwater flow of several South American rivers into the Caribbean. GABI is more complex that often assumed and it seems that variables other than a continuous terrestrial Isthmus have controlled the direction, timing and speed of migrations. The building of Panamanian landscape can be summarized in four phases, 1) a late Eocene large island in central Panama and the Azuero Peninsula, 2) an early Miocene large scale generation of terrestrial landscapes in Central America that connected central Panama with North America, 3) a full closure of CAS at 10 Ma, interrupting the exchange of deep waters between Caribbean and Pacific, and generating most of the landscape across the Isthmus. Exchange of shallow waters continued until 3.5 Ma, albeit intermittently. 4) A continuous terrestrial landscape across the Isthmus over the past 3.5 Ma.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5021264','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5021264"><span id="translatedtitle"><span class="hlt">Paleoclimatology</span> indicators of the Salt Wash member of the Upper Jurassic Morrison Formation near Jensen, Utah</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Medlyn, D.A. . Dept. of Geology); Bilbey, S.A. )</p> <p>1993-04-01</p> <p>The Upper Jurassic Morrison Formation has yielded one of the richest floras of the so-called transitional conifers'' of the Middle Mesozoic. Recently, a silicified axis of one of these conifers was collected from the Salt Wash member in essentially the same horizon as a previously reported partial Stegosaurus skeleton. In addition, two other axes of conifers were collected in the same immediate vicinity. Paleoecological considerations are extrapolated from the coniferous flora, vertebrate fauna and associated lithologies. Techniques of paleodendrology and relationships of extant/extinct environments are compared. The paleoclimatic conditions of the transitional conifers and associated dinosaurian fossils are postulated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/96276','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/96276"><span id="translatedtitle"><span class="hlt">Paleoclimatological</span> analysis of Late Eocene core, Manning Formation, Brazos County, Texas</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yancey, T.; Elsik, W.</p> <p>1994-09-01</p> <p>A core of the basal part of the Manning Formation was drilled to provide a baseline for paleoclimate analysis of the expanded section of siliciclastic sediments of late Eocene age in the outcrop belt. The interdeltaic Jackson Stage deposits of this area include 20+ cyclic units containing both lignite and shallow marine sediments. Depositional environments can be determined with precision and the repetitive nature of cycles allows comparisons of the same environment throughout, effectively removing depositional environment as a variable in interpretation of climate signal. Underlying Yegua strata contain similar cycles, providing 35+ equivalent environmental transacts within a 6 m.y. time interval of Jackson and Yegua section, when additional cores are taken. The core is from a cycle deposited during maximum flooding of the Jackson Stage, with deposits ranging from shoreface (carbonaceous) to midshelf, beyond the range of storm sand deposition. Sediments are leached of carbonate, but contain foram test linings, agglutinated forams, fish debris, and rich assemblages of terrestrial and marine palynomorphs. All samples examined contain marine dinoflagellates, which are most abundant in transgressive and maximum flood zones, along with agglutinated forams and fish debris. This same interval contains two separate pulses of reworked palynomorphs. The transgressive interval contains Glaphyrocysta intricata, normally present in Yegua sediments. Pollen indicates fluctuating subtropical to tropical paleoclimates, with three short cycles of cooler temperatures, indicated by abundance peaks of alder pollen (Alnus) in transgressive, maximum flood, and highstand deposits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/207882','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/207882"><span id="translatedtitle">Annually laminated sequences in the internal structure of some Belgian stalagmites -- Importance for <span class="hlt">paleoclimatology</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Genty, D.; Quinif, Y.</p> <p>1996-01-01</p> <p>Fifteen stalagmites from four caves and one sealed tunnel in southern Belgium are composed of alternations of annually deposited white-porous and dark-compact laminae. This is demonstrated by comparing the number of laminae with the local history of the site for modern stalagmites and with radioisotopic ages for Late Glacial and Holocene stalagmites. Annual cyclicity in the internal structure of these speleothems is explained by the highly seasonal variations of the water excess, which influences underground water flow. Comparison between climatic data and modern stalagmites of a closed tunnel shows that growth laminae can record climatic variations: (1) there is a good correlation (R = 0.84) between lamina thickness in a stalagmite and water excess; (2) during years with a high water excess, dark-compact laminae are more developed, which makes the speleothem darker. Vertical successions of several laminae represent microsequences that may have recorded climatic variations with a time resolution of 1/2 year. In a Late Glacial stalagmite, successive laminae microsequences form very regular cycles of 11 years separated by a thick dark-compact lamina. It is supported that, as for modern stalagmites, the thick dark-compact lamina corresponds to a period of high water excess. Hence, this 11-year cycle may reflect a climatic cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010AGUFM.A33J..01P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010AGUFM.A33J..01P&link_type=ABSTRACT"><span id="translatedtitle">The <span class="hlt">Paleoclimatological</span> Power of Biodiversity: 500 yrs of New York City Watershed Drought</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pederson, N.; Cook, E.; Vranes, K.</p> <p>2010-12-01</p> <p>The frequency of water restriction has increased over the last decade for New York City (NYC) despite: 1) its location in perhumid climate and 2) a reduction in water consumption since 1979. Population growth and future climate change could trigger more frequent restrictions and litigation over supplies. We update drought history for the NYC water supply region from the mid-1970’s reconstruction to better understand why water restrictions have increased. Using nested reconstruction techniques, 31 tree-ring chronologies comprised of 12 species account for 59.1% of the average May-Aug Palmer Drought Severity Index from 1895-2006 in the Hudson River Valley. Verification statistics indicate a reasonably strong reconstruction from 1507-2006. The new reconstruction covers an extended season versus the prior reconstruction (May-Aug vs Jul) and yet captures more annual variation in drought (59.1% vs 54%), supporting research indicating that the use of multiple species, including non-traditional species such as Liriodendron tulipifera, Betula lenta and Carya spp., might improve reconstruction skill. While the mid-1960s drought is still the most intense drought, it is closely rivaled by multi-annual droughts centered on 1637 and 1687. The new reconstruction indicates that the current 38-year pluvial is rivaled only by the 1719-1766 and 1619 periods. Other notable multi-annual pluvials are centered on 1541, 1581 and 1831. Multi-taper method analysis of the new reconstruction indicates periodicity of drought similar to the prior reconstruction, with significant peaks at 12-13, 16-18 and 23-years. The years during recent water restrictions rank as a minor droughts when viewed over the past 500-years. In the context of decreasing water usage and the current pluvial, it appears that the NYC region is not be prepared for the next significant drought.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/527444','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/527444"><span id="translatedtitle">Beryllium-10 in the Taylor Dome ice core: Applications to Antarctic glaciology and <span class="hlt">paleoclimatology</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Steig, E.J.</p> <p>1996-12-31</p> <p>An ice core was drilled at Taylor dome, East Antarctica, reaching to bedrock at 554 meters. Oxygen-isotope measurements reveal climatic fluctuations through the last interglacial period. To facilitate comparison of the Taylor Dome paleoclimate record with geologic data and results from other deep ice cores, several glaciological issues need to be addressed. In particular, accumulation data are necessary as input for numerical ice-flow-models, for determining the flux of chemical constituents from measured concentrations, and for calculation of the offset in age between ice and trapped air in the core. The analysis of cosmogenic beryllium-10 provides a geochemical method for constraining the accumulation-rate history at Taylor Dome. High-resolution measurements were made in shallow firn cores and snow pits to determine the relationship among beryllium-10 concentrations, wet and dry deposition mechanisms, and snow-accumulation rates. Comparison between theoretical and measured variations in deposition over the last 75 years constrains the relationship between beryllium-10 deposition and global average production rates. The results indicate that variations in geomagnetically-modulated production-rate do not strongly influence beryllium-10 deposition at Taylor Dome. Although solar modulation of production rate is important for time scales of years to centuries, snow-accumulation rate is the dominant control on ice-core beryllium-10 concentrations for longer periods. Results show that the Taylor Dome core can be used to provide new constraints on regional climate over the last 130,000 years, complementing the terrestrial and marine geological record from the Dry Valley, Transantarctic Mountains and western Ross Sea.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014E%26PSL.395..194C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014E%26PSL.395..194C"><span id="translatedtitle">Drip water isotopes in semi-arid karst: Implications for speleothem <span class="hlt">paleoclimatology</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cuthbert, Mark O.; Baker, Andy; Jex, Catherine N.; Graham, Peter W.; Treble, Pauline C.; Andersen, Martin S.; Ian Acworth, R.</p> <p>2014-06-01</p> <p>We report the results of the first multi-year monitoring and modelling study of the isotopic composition of drip waters in a semi-arid karst terrane. High temporal resolution drip rate monitoring combined with monthly isotope drip water and rainfall sampling at Cathedral Cave, Australia, demonstrates that drip water discharge to the cave occurs irregularly, and only after occasional long duration and high volume rainfall events, where the soil moisture deficit and evapotranspiration is overcome. All drip waters have a water isotopic composition that is heavier than the weighted mean annual precipitation, some fall along the local meteoric water line, others trend towards an evaporation water line. It is hypothesised that, in addition to the initial rainfall composition, evaporation of unsaturated zone water, as well as the time between infiltration events, are the dominant processes that determine infiltration water isotopic composition. We test this hypothesis using a soil moisture balance and isotope model. Our research reports, for the first time, the potential role of sub-surface evaporation in altering drip water isotopic composition, and its implications for the interpretation of speleothem δO18 records from arid and semi-arid regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70015791','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70015791"><span id="translatedtitle">A Miocene termite nest from southern Argentina and its <span class="hlt">paleoclimatological</span> implications</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bown, T.M.; Laza, J.H.</p> <p>1990-01-01</p> <p>A Miocene termitarium attributable to the extant termite Syntermes (Isoptera: Termitidae, Nasutitermitinae) is the first fossil termite nest reported from South America and possibly the oldest record of the Isoptera from that continent. A new ichnogenus and ichnospecies, Syntermesichnus fontanae, is proposed for this distinctive trace fossil. It differs from nests constructed by other members of the Nasutitermitinae in its architectural organization and its large size. -from Authors</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMPP51D1904R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMPP51D1904R"><span id="translatedtitle">Which boreholes do we need to resolve the Common Era in borehole <span class="hlt">paleoclimatology</span>?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rath, V.; Smerdon, J. E.; Gonzalez-Rouco, F. J.; Beltrami, H.</p> <p>2011-12-01</p> <p>The global database of borehole temperature profiles used to estimate paleoclimatic ground surface temperature histories (GSTHs) has typically focused on the last 500 years. his is mainly due to the fact that the borehole database is dominated by shallow boreholes (~200-300 m). Nevertheless, it has been shown that these boreholes may be too shallow for proper separation of the downwelling climatic transient and the long-term background steady-state signal associated with heat loss from the earth's interior. The mere inclusion of deeper boreholes, however, does not necessarily mitigate the problem. Borehole temperature profiles of any depth show the signatures of earlier climatic changes, including the strong warming following the last glacial maximum (LGM). In shallow boreholes this effect is very similar to a linear trend, usually cannot be discriminated from a steady-state geotherm, and is unlikely to strongly impact estimates of GSTHs spanning common-era timescales. In deeper boreholes, however, the signature of the LGM cannot be approximated linearly, and biases associated with the LGM may impact GSTH reconstructions during the Common Era. The combined incentive to employ deep boreholes for reliable estimation of the background steady-state signal, while limiting the LGM impacts on reconstructions of Common-Era GSTHs thus leads to an multi-objective optimization problem seeking a trade-off between the impacts of the two effects. Such an optimization of the borehole maximum depth criterion is investigated in this study using numerical models. A Monte Carlo ensemble approach is used to quantify the impact of various reconstruction decisions as temperature histories, error characteristics, thermophysical properties, and maximum borehole depths. The findings have implications for interpretations of current global reconstruction products and future efforts to analyze the global borehole database for Common-Era GSTH reconstructions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.2754R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.2754R"><span id="translatedtitle">Which boreholes do we need to resolve the Common Era in borehole <span class="hlt">paleoclimatology</span>?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rath, V.; Smerdon, J. E.; González-Rouco, J. F.; Beltrami, H.</p> <p>2012-04-01</p> <p>The global database of borehole temperature profiles used to estimate paleoclimatic ground surface temperature histories (GSTHs) has typically focused on the last 500 years. his is mainly due to the fact that the borehole database is dominated by shallow boreholes (~200-300 m). Nevertheless, it has been shown that these boreholes may be too shallow for proper separation of the downwelling climatic transient and the long-term background steady-state signal associated with heat loss from the earth's interior. The mere inclusion of deeper boreholes, however, does not necessarily mitigate the problem. Borehole temperature profiles of any depth show the signatures of earlier climatic changes, including the strong warming following the last glacial maximum (LGM). In shallow boreholes this effect is very similar to a linear trend, usually cannot be discriminated from a steady-state geotherm, and is unlikely to strongly impact estimates of GSTHs spanning common-era timescales. In deeper boreholes, however, the signature of the LGM cannot be approximated linearly, and biases associated with the LGM may impact GSTH reconstructions during the Common Era. The combined incentive to employ deep boreholes for reliable estimation of the background steady-state signal, while limiting the LGM impacts on reconstructions of Common-Era GSTHs thus leads to an multi-objective optimization problem seeking a trade-off between the impacts of the two effects. Such an optimization of the borehole maximum depth criterion is investigated in this study using numerical models. A Monte Carlo ensemble approach is used to quantify the impact of various reconstruction decisions as temperature histories, error characteristics, thermophysical properties, and maximum borehole depths. The findings have implications for interpretations of current global reconstruction products and future efforts to analyze the global borehole database for Common-Era GSTH reconstructions. (http://palma.fis.ucm.es/~volker/)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70017324','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70017324"><span id="translatedtitle">Palynology, <span class="hlt">paleoclimatology</span> and correlation of middle Miocene beds from Porcupine River (locality 90-1), Alaska</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>White, J.M.; Ager, T.A.</p> <p>1994-01-01</p> <p>Beds in the Upper Ramparts Canyon of the Porcupine River, Alaska (67?? 20' N, 141?? 20' W), yielded a flora rich in pollen of hardwood genera now found in the temperate climates of North America and Asia. The beds are overlain or enclosed by two basalt flows which were dated to 15.2 ?? 0.1 Ma by the 40Ar 39Ar method, fixing the period of the greatest abundance of warm-loving genera to the early part of the middle Miocene. The assemblage is the most northern middle Miocene flora known in Alaska. Organic bed 1 underlies the basalt and is older than 15.2 Ma, but is of early to middle Miocene age. The pollen assemblage from organic bed 1 is dominated by conifer pollen from the pine and redwood-cypress-yew families with rare occurrences of temperate hardwoods. Organic bed 2 is a forest floor containing redwood trees in life position, engulfed by the lowest basalt flow. A pine log has growth rings up to 1 cm thick. Organic beds 3 and 4 comprise lacustrine sediment and peat between the two basalt flows. Their palynoflora contain conifers and hardwood genera, of which about 40% have modern temperate climatic affinities. Hickory, katsura, walnut, sweet gum, wingnut, basswood and elm pollen are consistently present, and beech and oak alone make up about 20% of the pollen assemblage. A warm high latitude climate is indicated for all of the organic beds, but organic bed 3 was deposited under a time of peak warmth. Climate data derived by comparison with modern east Asian vegetation suggest that, at the time of deposition of organic bed 3, the Mean Annual Temperature (MAT) was ca. 9??C, the Warm Month Mean Temperature (WMMT) was ??? 20??C and the Cold Month Mean Temperature (CMMT) was ca. -2??C. In contrast, the modern MAT for the region is -8.6??C, WMMT is 12.6??C and CMMT is -28??C. Organic beds 3 and 4 correlate to rocks of the middle Miocene-late Seldovian Stage of Cook Inlet and also probably correlate to, and more precisely date, the lower third of the Suntrana Formation in the Alaska Range, beds at Unalaklect, part of the upper Mackenzie Bay sequence in the Beaufort-Mackenzie basin, and the Mary Sachs gravel of Banks Island. This suggests that forests with significant percentages of temperate deciduous angiosperms existed between latitudes 60?? and 72??N during the early middle Miocene. ?? 1994.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMPP33A1902B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMPP33A1902B"><span id="translatedtitle">High-resolution <span class="hlt">paleoclimatology</span> of the coastal margin of northernmost California during the past 7,300 years</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barron, J. A.; Heusser, L. E.; Addison, J. A.; Burky, D.; Kusler, J. E.; Finney, B.</p> <p>2013-12-01</p> <p>Piston core TN062 0550, located 13 km offshore of Eureka, California (40.866 deg. N, 124.572 deg. W, 550 m water depth), contains a continuous high-resolution climate record of the past 7,300 yr. Deposition occurred at nearly constant sedimentation rates averaging 94 cm/kyr based on 14C AMS dating of planktonic foraminifers. Pollen and marine ecosystem proxies (diatoms, silicoflagellates, wt. percent biogenic silica) studied at 50-70 yr sample resolution show a stepwise development of the climate/ oceanographic system off northernmost California. The relative contributions of Sequoia sempervirens (coastal redwood) pollen, a proxy for coastal fog associated with offshore upwelling, and biogenic silica concentrations (a proxy for siliceous export productivity) increase (two fold and three fold, respectively) in successive steps at ~5,000 yr BP and from ~2,400 to 2,000 yr BP. These increases are interpreted to reflect a progressive intensification of spring upwelling based on modern observations of the California Current system. At 5,000 yr BP diatom assemblages change from an assorted mixture of warm, temperate, and cool-water taxa to a low diversity temperate-oceanic assemblage dominated by Thalassionema spp. At ~2,400 yr BP the diatom assemblage transitions to a mixture of nearshore upwelling taxa and taxa associated with the central North Pacific Gyre. Silicoflagellate assemblages undergo a similar increase in the representation of modern seasonal proxies at ~3,000 yr BP that may reflect intensified ENSO variability. A two-fold increase in the relative contributions of Quercus (oak) and riparian Alnus (alder) pollen between ~3,800 and 2,000 yr BP likely signals a period of enhanced fluvial runoff associated with increased winter precipitation. Given the present day association of the Eel River system with the northwestern half of the western US winter precipitation dipole, these pollen data suggest that the ~3,800 and 2,000 yr interval was dominated by protracted negative Pacific Decadal Oscillation-like (PDO) conditions. The widespread occurrence of drought in the southwestern US between ~3,800 and 2,200 yr BP supports this interpretation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015BGeo...12.5899H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015BGeo...12.5899H&link_type=ABSTRACT"><span id="translatedtitle">Stable isotope <span class="hlt">paleoclimatology</span> of the earliest Eocene using kimberlite-hosted mummified wood from the Canadian Subarctic</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hook, B. A.; Halfar, J.; Gedalof, Z.; Bollmann, J.; Schulze, D. J.</p> <p>2015-10-01</p> <p>The recent discovery of well-preserved mummified wood buried within a subarctic kimberlite diamond mine prompted a paleoclimatic study of the early Eocene "hothouse" (ca. 53.3 Ma). At the time of kimberlite eruption, the Subarctic was warm and humid producing a temperate rainforest biome well north of the Arctic Circle. Previous studies have estimated that mean annual temperatures in this region were 4-20 °C in the early Eocene, using a variety of proxies including leaf margin analysis and stable isotopes (δ13C and δ18O) of fossil cellulose. Here, we examine stable isotopes of tree-ring cellulose at subannual- to annual-scale resolution, using the oldest viable cellulose found to date. We use mechanistic models and transfer functions to estimate earliest Eocene temperatures using mummified cellulose, which was well preserved in the kimberlite. Multiple samples of Piceoxylon wood within the kimberlite were crossdated by tree-ring width. Multiple proxies are used in combination to tease apart likely environmental factors influencing the tree physiology and growth in the unique extinct ecosystem of the Polar rainforest. Calculations of interannual variation in temperature over a multidecadal time-slice in the early Eocene are presented, with a mean annual temperature (MAT) estimate of 11.4 °C (1 σ = 1.8 °C) based on δ18O, which is 16 °C warmer than the current MAT of the area (-4.6 °C). Early Eocene atmospheric δ13C (δ13Catm) estimates were -5.5 (±0.7) ‰. Isotopic discrimination (Δ) and leaf intercellular pCO2 ratio (ci/ca) were similar to modern values (Δ = 18.7 ± 0.8 ‰; ci/ca = 0.63 ± 0.03 %), but intrinsic water use efficiency (Early Eocene iWUE = 211 ± 20 μmol mol-1) was over twice the level found in modern high-latitude trees. Dual-isotope spectral analysis suggests that multidecadal climate cycles somewhat similar to the modern Pacific Decadal Oscillation likely drove temperature and cloudiness trends on 20-30-year timescales, influencing photosynthetic productivity and tree growth patterns.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Geomo.246..156H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Geomo.246..156H"><span id="translatedtitle">Glacial and periglacial geomorphology and its <span class="hlt">paleoclimatological</span> significance in three North Ethiopian Mountains, including a detailed geomorphological map</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hendrickx, Hanne; Jacob, Miro; Frankl, Amaury; Nyssen, Jan</p> <p>2015-10-01</p> <p>Geomorphological investigations and detailed mapping of past and present (peri)glacial landforms are required in order to understand the impact of climatic anomalies. The Ethiopian Highlands show a great variety in past and contemporary climate, and therefore, in the occurrence of glacial and periglacial landforms. However, only a few mountain areas have been studied, and detailed geomorphological understanding is lacking. In order to allow a fine reconstruction of the impact of the past glacial cycle on the geomorphology, vegetation complexes, and temperature anomalies, a detailed geomorphological map of three mountain areas (Mt. Ferrah Amba, 12°51‧N 39°29‧E; Mt. Lib Amba, 12°04‧N 39°22‧; and Mt. Abuna Yosef, 12°08‧N 39°11‧E) was produced. In all three study areas, inactive solifluction lobes, presumably from the Last Glacial Maximum (LGM), were found. In the highest study area of Abuna Yosef, three sites were discovered bearing morainic material from small late Pleistocene glaciers. These marginal glaciers occurred below the modeled snowline and existed because of local topo-climatic conditions. Evidence of such Pleistocene avalanche-fed glaciers in Ethiopia (and Africa) has not been produced earlier. Current frost action is limited to frost cracks and small-scale patterned ground phenomena. The depression of the altitudinal belts of periglacial and glacial processes during the last cold period was assessed through periglacial and glacial landform mapping and comparisons with data from other mountain areas taking latitude into account. The depression of glacial and periglacial belts of approximately 600 m implies a temperature drop around 6 °C in the last cold period. This cooling is in line with temperature depressions elsewhere in East Africa during the LGM. This study serves as a case study for all the intermediate mountains (3500-4200 m) of the North Ethiopian highlands.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014BGD....1116269H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014BGD....1116269H"><span id="translatedtitle">Stable isotope <span class="hlt">paleoclimatology</span> of the earliest Eocene using kimberlite-hosted mummified wood from the Canadian Subarctic</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hook, B. A.; Halfar, J.; Gedalof, Z.; Bollmann, J.; Schulze, D.</p> <p>2014-11-01</p> <p>The recent discovery of well-preserved mummified wood buried within a subarctic kimberlite diamond mine prompted a paleoclimatic study of the early Eocene "hothouse" (ca. 53.3 Ma). At the time of kimberlite eruption, the Subarctic and Artic were warm and humid producing a temperate rainforest biome well north of the Arctic Circle. Previous studies have estimated mean annual temperatures in this region were 4-20 °C in the early Eocene, using a variety of proxies including leaf margin analysis, and stable isotopes (δ18O) of fossil cellulose. Here, we examine stable isotopes of tree-ring cellulose at subannual to annual scale resolution, using the oldest viable cellulose found to date. We use mechanistic models and transfer functions to estimate earliest Eocene temperatures using mummified cellulose, which was well preserved in the kimberlite. Multiple samples of Piceoxylon wood within the kimberlite were crossdated by tree-ring width. Multiple proxies are used in combination to tease apart likely environmental factors influencing the tree physiology and growth in the unique extinct ecosystem of the Polar rainforest. Calculations of interannual variation in temperature over a multidecadal time-slice in the early Eocene are presented, with a mean temperature estimate of 11.4 °C (1σ = 1.8 °C) based on δ18O. Dual-isotope spectral analysis suggests that multidecadal climate cycles similar to the modern Pacific Decadal Oscillation likely drove temperature and cloudiness trends on 20-30 year timescales.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active"><span>2</span></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_2 --> <div id="page_3" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="41"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/244082','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/244082"><span id="translatedtitle">Paleontology, <span class="hlt">paleoclimatology</span> and paleoecology of the late middle miocene Musselshell Creek flora, Clearwater County Idaho. A preliminary study of a new fossil flora</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Baghai, N.L.; Jorstad, R.B.</p> <p>1995-10-01</p> <p>The Musselshell Creek flora (12.0-10.5 Ma) of northern Idaho is used to reconstruct paleoclimatic and paleoecologic parameters of the Pacific Northwest during the late Middle Miocene. Other megafossil and microfossil floral records spanning 12.0-6.4 Ma are unknown from this region. The Musselshell Creek fossil flora, previously undescribed, is preserved in lacustrine clays and sediments that accumulated in a narrow valley surrounded by rugged terrain. Dominant taxa include dicotyledons and conifers. Most of the leaves are preserved as impressions or compressions. Some fossil leaves retained their original pigmentation, cellular anatomy, and organic constituents. Other fossils include excellent remains of pollen and spores, dispersed leaf cuticle, pyritized wood, and disarticulated fish bones. A destructive statistical analysis of one block of sediment, approximately 30 cm x 45 cm (1.5 sq. ft) recovered 14 orders, 23 families, and 34 genera of spermatophyte plant fossils. These floral elements are compared with two other earlier Miocene floras which were similarly sampled. Common megafossil genera include Quercus, Zizy-phoides, Taxodium, Alnus, Castanea, Magnolia, Acer, Ex-bucklandia, Sequoia, Populus, and Betula. The rare occurrence of Ginkgo leaves is a first record of this taxon in the Idaho Miocene. Additional plant taxa, are represented by palynomorphs. Common pollen taxa are Pinus, Abies, Carya, Quercus, and Tilia. Most of the megafossil and microfossil flora assemblage is characteristic of a streambank to floodplain environment that existed in a warm to cool temperate climate similar to the modern Mid-Atlantic coast of the United States. 47 refs., 5 figs., 4 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JAfES..96..220K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JAfES..96..220K"><span id="translatedtitle">Integrated biostratigraphy, stage boundaries and <span class="hlt">Paleoclimatology</span> of the Upper Cretaceous-Lower Eocene successions in Kharga and Dakhala Oases, Western Desert, Egypt</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khalil, H.; Al Sawy, S.</p> <p>2014-08-01</p> <p>The Upper Cretaceous-Lower Eocene succession in the studied sections is divided into four rock units that arranged from base to top: the Dakhla, Tarawan, Esna and the Thebes formations. Detailed study of the foraminifera and calcareous nannofossils has led to the recognition of 58 and 82 species, respectively. Based on planktonic foraminifera and calcareous nannofossils 8 planktonic foraminiferal biozones (CF4, P2, P3, P4, E1, E2, E3 and E4) have been recognized as well as 8 calcareous nannofossil biozones (CC25b, NP3, NP4, NP5, NP6, NP7/8, NP9, and NP10). At Gabal Teir/Tarawan section, Kharga Oasis, the Paleocene can be divided into three stages; Danian, Selandian and Thanetian. The Danian/Selandian boundary is placed at P3a/P3b zonal boundary (LO of Igorina albeari) which corresponds to the level of LO of Lithoptychius ulii, Fasciculithus pileatus, Fasciculithus involutus and Lithoptychius janii (upper part of Zone NP4). The Selandian/Thanetian boundary, on the other hand, can be traced within the foraminiferal Zone P4 (Globanomalina pseudomenardii Zone) and between the nannofossil zones NP6 and NP7/8 (LO of Discoaster mohleri). At Gabal Ghanima section, the Paleocene/Eocene boundary is located within the lower part of the Esna Formation. It can be traced at the base of planktonic foraminiferal Zone E1 (LOs of Acarinina africana, A sibaiyaensis and Morozovella allinsoensis), and at the NP9a/NP9b subzonal boundary (LO of Rhomboaster spp). However, the lower Eocene succession seems to be condensed and punctuated by minor hiatus (absence of Subzone NP10a). The dominance of cool water nannofossil species in the late Maastrichtian and early Danian interval suggests a gradual decrease in the surface water paleotemperature. However, a slight warming condition prevailed around the Danian/Selandian transition as evidenced by the warm water nannofossil species. At the P/E boundary interval, the high abundance of warm-water taxa (e.g. Discoaster, Sphenolithus, Rhomboaster, Tribrachiatus and Pontosphaera species) indicates a warm-water paleotemperatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5878658','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5878658"><span id="translatedtitle">Variations in [sup 18]O/[sup 16]O ratios of kaolinites within a lateritic profile: Their significance for laterite genesis and isotope <span class="hlt">paleoclimatology</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Giral, S.; Girard, J.P.; Savin, S.M. . Dept. of Geological Sciences); Nahon, D.B. )</p> <p>1992-01-01</p> <p>The authors have made an integrated study of the field occurrence, petrology, mineralogy and crystallography, and oxygen isotope geochemistry of an active lateritic profile from about 60 km north of Manaus (Amazonia, Brazil). The parent rock is an arkosic sandstone. The delta O-18 values of kaolinites from the profile are far from uniform. The total range is about 2.4 per mil (18.7 to 21.1 per mil). The calculated delta O-18 value of kaolinite in isotopic equilibrium with local average precipitation and mean annual temperature is 19.6 per mil, within the range of the measured values. Kaolinite of each of several textural occurrences also shows significant isotopic variation both vertically and within a given horizon. Different size fractions of kaolinite of a single textural occurrence within a single horizon also exhibit differences in delta O-18 values. At depths below a few meters, they expect the temperature and the delta O-18 values of the soil water profile to be relatively uniform at any time. If this is so, the variations in delta O-18 values of the kaolinites would suggest that the formation of different populations occurred at different times. They cannot yet distinguish between variations of conditions that were seasonal and variations that occurred on scales of many years. However, it is most important to resolve the causes of these variations before using the delta O-18 values of soil clays for purposes of paleoclimatic reconstruction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70011834','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70011834"><span id="translatedtitle">Lower Eocene alluvial paleosols (Willwood Formation, Northwest Wyoming, U.S.A.) and their significance for paleoecology, <span class="hlt">paleoclimatology</span>, and basin analysis</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bown, T.M.; Kraus, M.J.</p> <p>1981-01-01</p> <p>The lower Eocene Willwood Formation of northwest Wyoming is a 700 m thick accumulation of alluvial floodplain and channel mudstones and sandstones, nearly all of which show paleopedogenic modifications. Pedogenesis of Willwood sandstones is indicated by taproot and vertebrate and invertebrate bioturbation, early local cementation by calcium carbonate, and thin illuviation cutans on clastic grains. Pedogenesis in Willwood mudstones is indicated by plant bioturbation, insect and other invertebrate burrow casts and lebensspuren; free iron, aluminum, and manganese mobilization, including hydromorphic gleying; sesquioxide and calcareous glaebule formation in lower parts of the solum; presence of clay-rich and organic carbon-rich zones; and well differentiated epipedons and albic and spodic horizons. Probable A horizons are also locally well developed. Occurrence of variegated paleosol units in thick floodplain mudstone deposits and their association with thin, lenticular, and unconnected fluvial sandstones in the Willwood Formation of the central and southeast Bighorn Basin suggest that these soils formed during times of rapid sediment accumulation. The tabular geometry and lateral persistence of soil units as well as the absence of catenization indicate that Willwood floodplains were broad and essentially featureless. All Willwood paleosols were developed on alluvial parent materials and are complex in that B horizons of younger paleosols were commonly superimposed upon and mask properties of suspected A and B horizons of the next older paleosols. The soils appear to be wet varieties of the Spodosol and Entisol groups (aquods and ferrods, and aquents, respectively), though thick, superposed and less mottled red, purple, and yellow paleosols resemble some ultisols. Most Willwood paleosols resemble warm temperate to subtropical alluvial soils that form today under alternating wet and dry conditions and (or) fluctuating water tables. The up-section decrease in frequency of gley mottles, increase in numerical proportion and thickness of red versus orange coloration, and increase in abundance of calcrete glaebules indicate better drained soils and probably drier climate in late Willwood time. This drying is believed to be related to creation of rain shadows and spacing of rainfall (but not necessarily decrease in absolute rainfall) due to progressive tectonic structural elevation of the mountainous margins of the Bighorn Basin. ?? 1981.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5180500','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5180500"><span id="translatedtitle">Relation between D/H ratios and sup 18 O/ sup 16 O ratios in cellulose from linen and maize--Implications for <span class="hlt">paleoclimatology</span> and for sindonology</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>DeNiro, M.J.; Sternberg, L.D.; Marino, B.D. ); Druzik, J.R. )</p> <p>1988-09-01</p> <p>The {sup 18}O/{sup 16}O ratios of cellulose and the D/H ratios of cellulose nitrate were determined for linen, a textile produced from the fibers of the flax plant Linum usitatissimum, and for maize (Zea mays) from a variety of geographic locations in Europe, the Middle East, and North and South America. The regression lines of {delta}D values on {delta}{sup 18}O values had slopes of 5.4 and 5.8 for the two species. Statistical analysis of results reported in the only other study in which samples of a single species that grew under a variety of climatic conditions were analyzed yielded slopes of {approximately}6 when {delta}D values of cellulose nitrate were regressed on {delta}{sup 18}O values of cellulose. The occurrence of this previously unrecognized relationship in three species suggests it may obtain in other plants as well. Determining the basis for this relationship, which is not possible given current understanding of fractionation of the isotopes of oxygen and hydrogen by plants, should lead to increased understanding of how D/H and {sup 18}O/{sup 16}O ratios in cellulose isolated from fossil plants are related to paleoclimates. The separation of most linen samples from Europe from those originating in the Middle East when {delta}D values are plotted against {delta}{sup 18}O values suggests it may be possible to use the isotope ratios of cellulose prepared from the Shroud of Turin to resolve the controversy concerning its geographic origin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1988GeCoA..52.2189D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1988GeCoA..52.2189D&link_type=ABSTRACT"><span id="translatedtitle">Relation between D/H ratios and 18O /16O ratios in cellulose from linen and maize - Implications for <span class="hlt">paleoclimatology</span> and for sindonology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>DeNiro, Michael J.; Sternberg, Leonel D.; Marino, Bruno D.; Druzik, James R.</p> <p>1988-09-01</p> <p>The 18O /16O ratios of cellulose and the D/H ratios of cellulose nitrate were determined for linen, a textile produced from the fibers of the flax plant Linum usitatissimum, and for maize ( Zea mays) from a variety of geographic locations in Europe, the Middle East, and North and South America. The regression lines of δD values on δ 18O values had slopes of 5.4 and 5.8 for the two species. Statistical analysis of results reported in the only other study in which samples of a single species (the silver fir Abies pindrow) that grew under a variety of climatic conditions were analyzed yielded slopes of ~6 when δD values of cellulose nitrate were regressed on δ 18O values of cellulose. The occurrence of this previously unrecognized relationship in three species suggests it may obtain in other plants as well. Determining the basis for this relationship, which is not possible given current understanding of fractionation of the isotopes of oxygen and hydrogen by plants, should lead to increased understanding of how D/H and 18O /16O ratios in cellulose isolated from fossil plants are related to paleoclimates. The separation of most linen samples from Europe from those originating in the Middle East when δD values are plotted against δ 18O values suggests it may be possible to use the isotope ratios of cellulose prepared from the Shroud of Turin to resolve the controversy concerning its geographic origin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMPP31C1896T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMPP31C1896T"><span id="translatedtitle">Uranium-series dating of travertine from Soda Dam, New Mexico: Constructing a history of deposition, with implications for landscape evolution, paleohydrology and <span class="hlt">paleoclimatology</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tafoya, A. J.; Crossey, L. J.; Karlstrom, K. E.; Kolomaznik, M.; Polyak, V. J.; Asmerom, Y.; Cox, C. J.</p> <p>2011-12-01</p> <p>We apply high precision uranium series geochronology to decipher rates of change in travertine growth at Soda Dam, New Mexico which preserve a paleohydrology record for parts of the last 500 ka. Travertine-depositing springs occur along the intersection of the Soda Dam fault, part of the Jemez fault zone, and the Jemez River. Modern travertine-depositing hot springs are part of the Valles geothermal system, which has been active throughout the Quaternary. Previous U-series dates (Goff et al., 1987) on the Soda Dam travertines were: Soda Dam = 4.8±0.2 ka; Deposit A (west side) = 215±40 ka and >350 ka; Deposit B (east side) = 98±7 ka near top and 58±3 ka in the core; Deposit C (southeast side) = 107±5 ka near base. New dates provide improved geochronologic and geologic context with respect to timing of movement in the western side of the Rio Grande Rift and the Pajarito fault, incision rates of the Jemez River, and timing of travertine accumulation. Large volumes of travertine preserved high in the landscape yield an age of 560.3 ± 324 ka. Inset into this deposit are Jemez River gravels that are 30 m above the modern river with travertine coating on cobbles giving an age of 200.6±2.1 ka and gravels cut by sparite sills of 109 ± 1.5 ka. These ages give river incision rates of 150 m/Ma over the last 200 ka. Deposit B is a mound accumulation on the east side of the river that developed on a banded central fissure ridge, much like the modern Soda Dam. The mound accumulation is 138.4 ± 1.1 ka near the base and 78.2 ± 1.6 ka at the top; the central fissure has a 20 cm thick vein system a portion of which yields a more restricted age range from 133.9±11 ka toward the walls to 95.8±1.0 ka toward the center. The combined data indicate the fissure/mound system was active from 138-78 ka, a 60,000 yr interval that spans the transition from glacial marine isotope stage 6 into interglacial marine isotope stage 5. Accumulation rates on the vein system of deposit B are 2.9 mm/ka from 134 to 117 ka and 2.0 mm/ka from 117 to 96 ka indicating a higher accumulation rate of travertine during the wetter glacial marine isotope stage 6 versus the interglacial marine isotope stage 5. Outcrop C, also on the east side, is 103.2 ± 0.5 ka at the base and 101.7 ± 0.5 ka at the top and gives a river incision rate of 160 m/Ma over the last 100 ka. Longer term average incision for the Jemez River are 195 m/Ma over the last 1.2 Ma and 230 m/Ma over the last 0.64 Ma. Our results produce incision rates that are generally consistent with previously reported incision rates and suggest semi-steady bedrock river incision, with perhaps a slight slowing over the last 200 ka. The dates also indicate persistent deposition along the Soda Dam fault system over at least 500 thousand years. Stable isotope values of the dated travertines range from δ180 = -19 to -6.5 per mil (PDB), reflecting variations in local spring chemistry and a potential paleoclimate record that will be investigated using closer spaced sampling and multiple proxies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5739644','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5739644"><span id="translatedtitle">Warm to cold polar climate transitions over the last 15,000 years: A <span class="hlt">paleoclimatology</span> record from the raised beaches of northern Norway</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fletcher, C.H. ); Fairbridge, R.H. ); Moeller, J.K. ); Long, A.J. )</p> <p>1991-03-01</p> <p>Because of the strength of the cold, dry arctic high pressure vortex, and the absence of multiple air-mass sources, climate records from the polar region tend to display a cleaner signal than those from mid-latitude settings. The high arctic presents unique opportunities for the prediction of the natural background pattern of climate change prior to the disturbances generated by manmade atmospheric pollutants. The Varanger Peninsula of northernmost Norway was extensively depressed by an ice dome during the last glacial stage. Deglaciation was accompanied by isostatic recovery at a steady though exponentially decaying rate. Superimposed on the rising land is a discontinuous staircase of cobble beach ridges, deposited during the postglacial period by storms at the coast. The ridges are constructed during brief episodes of weather- and tide-related elevation of sea level and wave run-up. Storminess periods can only occur in the absence of sea ice associated with several decades of mild, relatively warm temperatures. A history of local relative sea level is constructed from over 70 radiocarbon dates of various water-level indicators. The sea-level history is used to construct a chronology of beach-ridge building that documents the cyclic, a periodic nature of arctic storminess conditions. The authors date a dynamic signal with multiple climate transitions from warm, stormy conditions to cool, calm conditions occurring roughly every 200 years between 15,000 years ago to 10,000 years ago. Throughout the Holocene the climate is more settled with longer periods separating the major warm to cool transitions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70103310','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70103310"><span id="translatedtitle">High-resolution <span class="hlt">paleoclimatology</span> of the Santa Barbara Basin during the Medieval Climate Anomaly and early Little Ice Age based on diatom and silicoflagellate assemblages in Kasten core SPR0901-02KC</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Barron, John A.; Bukry, David B.; Hendy, Ingrid L.</p> <p>2015-01-01</p> <p>Diatom and silicoflagellate assemblages documented in a high-resolution time series spanning 800 to 1600 AD in varved sediment recovered in Kasten core SPR0901-02KC (34°16.845’ N, 120°02.332’ W, water depth 588 m) from the Santa Barbara Basin (SBB) reveal that SBB surface water conditions during the Medieval Climate Anomaly (MCA) and the early part of the Little Ice Age (LIA) were not extreme by modern standards, mostly falling within one standard deviation of mean conditions during the pre anthropogenic interval of 1748 to 1900. No clear differences between the character of MCA and the early LIA conditions are apparent. During intervals of extreme droughts identified by terrigenous proxy scanning XRF analyses, diatom and silicoflagellate proxies for coastal upwelling typically exceed one standard deviation above mean values for 1748-1900, supporting the hypothesis that droughts in southern California are associated with cooler (or La Niña-like) sea surface temperatures (SSTs). Increased percentages of diatoms transported downslope generally coincide with intervals of increased siliciclastic flux to the SBB identified by scanning XRF analyses. Diatom assemblages suggest only two intervals of the MCA (at ~897 to 922 and ~1151 to 1167) when proxy SSTs exceeded one standard deviation above mean values for 1748 to 1900. Conversely, silicoflagellates imply extreme warm water events only at ~830 to 860 (early MCA) and ~1360 to 1370 (early LIA) that are not supported by the diatom data. Silicoflagellates appear to be more suitable for characterizing average climate during the 5 to 11 year-long sample intervals studied in the SPR0901-02KC core than diatoms, probably because diatom relative abundances may be dominated by seasonal blooms of a particular year.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.C51A0934B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.C51A0934B"><span id="translatedtitle">The Ice Core Data Gateway: The one stop gateway to ice core data held at the Antarctic Glaciological Data Center (AGDC), the World Data Center for <span class="hlt">Paleoclimatology</span>, and the Arctic System Science's Data Coordination Center (ADCC).</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bauer, R.; Scambos, T.; Eakin, M.; Anderson, D.; McNeave, C.</p> <p>2002-12-01</p> <p>The Ice Core Data Gateway archives and distributes physical and geochemical data from ice cores collected in both the northern and southern hemispheres. Typical data sets include age-depth relationships, oxygen and hydrogen isotope concentrations, major element chemistry, accumulation rates and pollen. The data are in general presented as ASCII files with a short text metadata description. The archive is designed to provide access to ice core data sets over the long term, thereby making them available for comparison with future data: a critical component of change detection studies. By facilitating broad data access, the center promotes interdisciplinary scientific research. Investigators are encouraged to contribute data sets derived from ice cores to the Ice Core Data Gateway. Data center staff will work with you to compile data set documentation prior to making the data available to users. Contributing scientists are given prominent recognition in the documentation, and while the data center answers technical questions about format, citations for usage, etc., it can refer scientific questions to contributors if requested. Contributing your data to the Ice Core Data Gateway and associated data centers directly supports to NSF Office of Polar Programs Guidelines and Award Conditions for Scientific Data (http://www.nsf.gov/pubsys/ods/getpub.cfm?opp991). This effort is being coordinated with the West Antarctic Ice Sheet (WAIS) Initiative and U.S. component of the International Trans Antarctic Science Expedition (ITASE), and includes data from the Arctic System Science Program's Greenland Ice Sheet Project 2 (GISP2) ice core.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=274935','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=274935"><span id="translatedtitle">Hidden histories and ancient mysteries of witches, plants and fungi</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>Convergent findings from archaeobotany, molecular genetics, <span class="hlt">paleoclimatology</span> and comparative linguistics mandate revisions to agricultural history. Recent research has demonstated that stripe rust (agent: Puccinia striiformis) and scald (species in Rhynchosporium) moved into western and northern Eu...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999wceh.book.....H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999wceh.book.....H"><span id="translatedtitle">Warm Climates in Earth History</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huber, Brian T.; MacLeod, Kenneth G.; Wing, Scott L.</p> <p>1999-12-01</p> <p>The study of greenhouse climates in the earth's past leads to a greater understanding of the factors that influence today's climate. In this fully integrated volume, leading experts in <span class="hlt">paleoclimatology</span> present cutting edge paleontological, geological, and theoretical research to assess intervals of global warmth. Coverage examines warm climate intervals during the Paleozoic, Mesozoic and Cenozoic from the same perspectives: oceanic and terrestrial, theoretical and observational. This approach illuminates the differences and, more importantly, the commonalities of warm climate intervals. The book also provides a comprehensive overview of the advantages and limitations of different types of climate models that are currently used, and it discusses major factors that have caused global climatic change across geologic time scales. Central problems that remain unresolved are clearly identified. The book will be of great interest to researchers in <span class="hlt">paleoclimatology</span>, and it will also be useful as a supplementary text in advanced undergraduate or graduate level courses in <span class="hlt">paleoclimatology</span> and earth science.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1016516','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1016516"><span id="translatedtitle">The Journey of Man: A Genetic Odyssey</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wells, Spencer</p> <p>2004-02-25</p> <p>Evidence from paleoanthropology and genetics has consistently shown that our species originated in Africa. Recent results from the Y-chromosome confirm this, but further posit that all modern humans were still living in Africa 60,000 years ago. The case for a recent 'African exodus' will be discussed, with supporting evidence drawn from DNA polymorphisms, <span class="hlt">paleoclimatology</span> and archaeology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005EOSTr..86..110.&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005EOSTr..86..110.&link_type=ABSTRACT"><span id="translatedtitle">In Memoriam; Recent Ph.D.s; Honors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p></p> <p>2005-03-01</p> <p>In Memoriam. John C. Freeman, 84, 18 November 2004, Atmospheric Sciences, 1991. Thomas Gold, 84, 22 June 2004, Retired Life Member, AGU Fellow, Planetology, 1958. William H. Pickering, 93, 2004, Retired Life Member, AGU Fellow, Planetology, 1962. Geoff O. Seltzer, 45, 15 January 2005, Paleoceanography/<span class="hlt">Paleoclimatology</span>, 1990.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6067897','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6067897"><span id="translatedtitle">Physical geology</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Skinner, B.; Porter, S.</p> <p>1987-01-01</p> <p>The book integrates current thinking on processes (plate techtonics, chemical cycles, changes throughout geologic time). It is an introduction to investigations into the way the earth works, how mountains are formed, how the atmosphere, hydrosphere, crust and mantle interact with each other. Treatments on climate, <span class="hlt">paleoclimatology</span> and landscape evolution are included, as is a discussion on how human activity affects geological interactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/99419','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/99419"><span id="translatedtitle">Soil microscopy and micromorphology</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>FitzPatrick, E.A.</p> <p>1993-12-31</p> <p>This book is a valuable resource to help geologists integrate knowledge of soil science into the endeavor of identifying paleosols. Attention is focused on the following: soil micromorphology, including sample preparation techniques; and physical and chemical properties. Various applications are presented of micromorphological soil study. Included is coverage on the disciplines of agriculture, archeology, engineering, geomorphology, <span class="hlt">paleoclimatology</span>, paleopedology, and microbiology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7065692','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/7065692"><span id="translatedtitle">Climate and the collapse of civilization</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Abate, T.</p> <p>1994-09-01</p> <p>This article looks at the archaeological debate over two important questions: whether abrupt climate changes caused or contributed to the collapse of ancient civilizations and, if the archaeological and <span class="hlt">paleoclimatological</span> record yields evidence to that effect, what would it mean in a world that today debates whether industrial civilization is altering Earth's climate with uncertain consequences. Areas discussed include the following: climate hints from archaeological sites; hesitations about whether climate change caused civilizations to collapse; and the interdisciplinary checks on each side.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940017186','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940017186"><span id="translatedtitle">Workshop on Early Mars: How Warm and How Wet?, part 1</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Squyres, S. (Editor); Kasting, J. (Editor)</p> <p>1993-01-01</p> <p>This volume contains papers that have been accepted for presentation at the Workshop on Early Mars: How Warm and How Wet?, 26-28 Jul. 1993, in Breckenridge, CO. The following topics are covered: the Martian water cycle; Martian <span class="hlt">paleoclimatology</span>; CO2/CH4 atmosphere on early Mars; Noachian hydrology; early Martian environment; Martian weathering; nitrogen isotope ratios; CO2 evolution on Mars; and climate change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6922548','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6922548"><span id="translatedtitle">Volcanic eruptions: Atmospheric effects. May 1970-February 1990 (A Bibliography from the NTIS data base). Report for May 1970-February 1990</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Not Available</p> <p>1990-03-01</p> <p>This bibliography contains citations concerning gaseous and particulate contributions to the Earth's atmosphere from volcanoes, and the effects these substances have on the climate and the environment. Case studies of specific volcanic eruptions; detection and measurement of volcanic gases, aerosols, and particulates in the atmosphere; environmental effects on the biota; long and short term climatological effects; <span class="hlt">paleoclimatology</span> and volcanoes; atmospheric and transport modelling; and solar radiation inhibition are among the topics discussed. (Contains 157 citations fully indexed and including a title list.)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5338440','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5338440"><span id="translatedtitle">Volcanic eruptions: Atmospheric effects. (Latest citations from the NTIS bibliographic database). Published Search</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Not Available</p> <p>1994-02-01</p> <p>The bibliography contains citations concerning gaseous and particulate contributions to the Earth's atmosphere from volcanoes, and the effects these substances have on the climate and the environment. Citations cover case studies of specific volcanic eruptions, detection and measurement of volcanic gases and aerosols in the atmosphere, environmental effects on the biota, long and short term climatological effects, <span class="hlt">paleoclimatology</span> and volcanoes, atmospheric and transport modeling, and solar radiation inhibition. (Contains a minimum of 214 citations and includes a subject term index and title list.)</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMPP22A0492E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMPP22A0492E"><span id="translatedtitle">Paleolimnology Web Portal: A Web Site Designed to Increase Paleolimnology Data Availability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eakin, C. M.; Moy, C. M.; Habermann, T.; Gross, W. S.; Keltner, J. M.</p> <p>2001-12-01</p> <p>Despite widespread use of lacustrine records to interpret paleolimnologic and paleoclimatic change, there is a large gap between the data published in peer-reviewed journals and those submitted for archive and available to other researchers online. A primary goal of the World Data Center (WDC) for <span class="hlt">paleoclimatology</span> and the International Geosphere-Biosphere Programme (IGBP) - Past Global Changes (PAGES) core programme is to have full and open sharing of all data sets needed for global change studies. To help improve the quantity and quality of data submitted to the WDC for <span class="hlt">Paleoclimatology</span>, we are developing online data submission and advanced interactive browse and access tools. Our poster presents a new web-site designed to make paleolimnology data more accessible by incorporating web-based data submission forms, a multi-proxy relational database, and interactive mapping tools. The WDC for <span class="hlt">Paleoclimatology</span> is currently designing intuitive and streamlined web-based submission forms, which will allow investigators to quickly submit their data and metadata on-line. We are also importing all existing data and metadata in our archives into a multiproxy relational database that will allow users to quickly query and retrieve paleolimnological data, as well as display the data in various formats. Furthermore, we are implementing two Paleolimnology mapping tools that will allow users to search, display, and query data in a geographical format. The first tool, WebMapper, uses a Java applet to draw maps and display metadata. This will be supplemented by a plotting tool that will provide basic plotting functions to allow users to examine data before downloading them. The second mapping tool, ArcIMS, allows users to overlay paleoclimatic data with various GIS data sets in addition to providing basic spatial analysis functions. We believe that these new web-based features will encourage more extensive data sharing and submission, making paleolimnological data more available and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009Ge%26Ae..49.1056O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009Ge%26Ae..49.1056O"><span id="translatedtitle">Quasisecular cyclicity in the climate of the Earth's Northern Hemisphere and its possible relation to solar activity variations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ogurtsov, M. G.; Jungner, H.; Lindholm, M.; Helama, S.; Dergachev, V. A.</p> <p>2009-12-01</p> <p><span class="hlt">Paleoclimatological</span> reconstructions of temperature of the Earth’s Northern Hemisphere for the last thousand years have been studied using the up-to-date methods of statistical analysis. It has bee indicated that the quasisecular (a period of 60-130 years) cyclicity, which is observed in the climate of the Earth’s Northern Hemisphere, has a bimodal structure, i.e., being composed of the 60-85 and 85-130 year periodicities. The possible relation of the quasisecular climatic rhythm to the corresponding Gleissberg solar cycle has been studied using the solar activity reconstructions performed with the help of the solar paleoastrophysics methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5765017','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5765017"><span id="translatedtitle">Greenhouse effect and the global climate. (Latest citations from the Aerospace database). Published Search</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Not Available</p> <p>1993-09-01</p> <p>The bibliography contains citations concerning terrestrial climatic changes known as the greenhouse effect. The greenhouse effect is an accumulation of carbon dioxide and other gases that retain solar-induced heat, thereby increasing the average global temperature. Modeling studies, measurements of atmospheric gases, pollutants and temperatures, studies of climatic records for occurrence of similar changes (<span class="hlt">paleoclimatology</span>), prediction of environmental changes due to the greenhouse effect, government energy policy as a result of possible climate change, and the contributions of manmade and natural pollutants to the greenhouse effect are among the topics discussed. (Contains a minimum of 52 citations and includes a subject term index and title list.)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008EOSTr..89...82M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008EOSTr..89...82M&link_type=ABSTRACT"><span id="translatedtitle">Climate Warming and 21st-Century Drought in Southwestern North America</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>MacDonald, Glen M.; Stahle, David W.; Diaz, Jose Villanueva; Beer, Nicholas; Busby, Simon J.; Cerano-Paredes, Julian; Cole, Julie E.; Cook, Edward R.; Endfield, Georgina; Gutierrez-Garcia, Genaro; Hall, Beth; Magana, Victor; Meko, David M.; Méndez-Pérez, Matias; Sauchyn, David J.; Watson, Emma; Woodhouse, Connie A.</p> <p>2008-02-01</p> <p>Since 2000, southwestern North America has experienced widespread drought. Lakes Powell and Mead are now at less than 50% of their reservoir capacity, and drought or fire-related states of emergency were declared this past summer by governors in six western states. As with other prolonged droughts, such as the Dust Bowl during the 1930s, aridity has at times extended from northern Mexico to the southern Canadian prairies. A synthesis of climatological and <span class="hlt">paleoclimatological</span> studies suggests that a transition to a more arid climate may be occurring due to global warming, with the prospect of sustained droughts being exacerbated by the potential reaction of the Pacific Ocean to warming.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730019549','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730019549"><span id="translatedtitle">Hydrogeology of closed basins and deserts of South America, ERTS-1 interpretations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stoertz, G. E.; Carter, W. D.</p> <p>1973-01-01</p> <p>Images from the Earth Resources Technology Satellite (ERTS-1) contain data useful in studies of hydrogeology, geomorphology, and <span class="hlt">paleoclimatology</span>. Sixteen Return Beam Vidicon (RBV) images and 15 Multi-Spectral Scanner (MSS) images were studied. These covered deserts and semidesert areas in southwestern Bolivia, northwestern Argentina, northern Chile, and southeastern Peru from July 30 to November 17, 1972. During the first 3 months after launching, high-quality cloud-free imagery was obtained over approximately 90 percent of the region of interior drainage, or an area of 170,000 square miles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhyA..440..155F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhyA..440..155F"><span id="translatedtitle">A phase-transition model for the rise and collapse of ancient civilizations: A pre-ceramic Andean case study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Flores, J. C.</p> <p>2015-12-01</p> <p>For ancient civilizations, the shift from disorder to organized urban settlements is viewed as a phase-transition simile. The number of monumental constructions, assumed to be a signature of civilization processes, corresponds to the order parameter, and effective connectivity becomes related to the control parameter. Based on parameter estimations from archaeological and <span class="hlt">paleo-climatological</span> data, this study analyzes the rise and fall of the ancient Caral civilization on the South Pacific coast during a period of small ENSO fluctuations (approximately 4500 BP). Other examples considered include civilizations on Easter Island and the Maya Lowlands. This work considers a typical nonlinear third order evolution equation and numerical simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7175335','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/7175335"><span id="translatedtitle">Volcanic eruptions: atmospheric effects. (Latest citations from the NTIS data base). Published Search</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Not Available</p> <p>1992-04-01</p> <p>The bibliography contains citations concerning gaseous and particulate contributions to the Earth's atmosphere from volcanoes, and the effects these substances have on the climate and the environment. Case studies of specific volcanic eruptions; detection and measurement of volcanic gases, aerosols, and particulates in the atmosphere; environmental effects on the biota; long and short term climatological effects; <span class="hlt">paleoclimatology</span> and volcanoes; atmospheric and transport modelling; and solar radiation inhibition are among the topics discussed. (Contains a minimum of 179 citations and includes a subject term index and title list.)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016QuRes..85....1W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016QuRes..85....1W"><span id="translatedtitle">In Memoriam: Herbert E. Wright, Jr., 1917-2015</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Whitlock, Cathy; Stein, Julie K.; Fritz, Sherilyn</p> <p>2016-01-01</p> <p>Professor Herbert E. Wright passed away on November 12, 2015 in his 98th year. His passing leaves many in Quaternary community reflecting on his enormous contributions to the discipline, as well as the many ways in which he touched our lives. Herb's legacy, writ large, is evidenced by decades of scholarly contributions to the fields of glacial geology, geomorphology, paleoecology, paleolimnology, <span class="hlt">paleoclimatology</span>, and archaeology. During the course of his career, he authored and co-authored over 250 scientific publications and co-edited 16 influential volumes on the Quaternary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMPP51A2256T&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMPP51A2256T&link_type=ABSTRACT"><span id="translatedtitle">Seasonal Streamflow Reconstructions of the Choctawhatchee River (AL-USA)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tootle, G. A.; Therrell, M.; Moat, T.; Meko, M.</p> <p>2015-12-01</p> <p>Tree ring samples were collected from Bald Cypress (Taxodium distichum) species in watersheds adjacent to the Choctawhatchee River (Alabama and Florida - USA). These samples were collected to update an existing tree ring proxy that was developed in the late 1980's and early 1990's (Stahle and Cleaveland, 1992, IGBP PAGES/World Data Center for <span class="hlt">Paleoclimatology</span> Data Contribution # FL001, Choctawhatchee River. NOAA/NCDC <span class="hlt">Paleoclimatology</span> Program, Boulder, Colorado, USA). The motivation for updating the tree ring proxy was to determine if recent droughts identified in historic unimpaired Choctawhatchee River streamflow records were reflected in Bald Cypress tree ring growth. Historic streamflow from 1934 to 2013 was obtained for the USGS station at Newton, Alabama and one, five and ten-year droughts were identified and ranked. Many of the most severe droughts were identified in recent (~2000 to present) records (see Figure). Combining the new tree ring proxy with other regional proxies, seasonal streamflow was reconstructed for the Choctawhatchee River Newton, Alabama gage. The reconstructed streamflow allows water managers and planners to observe past wet and dry periods that may exceed magnitude, duration and/or severity of wet and dry periods in observed records.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUSM...H22D07B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUSM...H22D07B"><span id="translatedtitle">The Ice Core Data Gateway: A Multi-Agency Effort to Provide On-line Access to Ice Core Data Sets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bauer, R.; Scharfen, G.; Scambos, T.; Eakin, M.; Anderson, D.</p> <p>2001-05-01</p> <p>The NSF-funded Antarctic Glaciological Data Center (AGDC) at the National Snow and Ice Data Center provides data management for the U.S. Antarctic Glaciological Program including ice core data from the Antarctic. The World Data Center for <span class="hlt">Paleoclimatology</span> archives ice core data sets from many sites, globally. Recently, the AGDC, the WDC for <span class="hlt">Paleoclimatology</span> and representatives from the International Ice Core Data Cooperative have developed a coordinated and cooperative approach to ice core data management. The Ice Core Data Gateway provides a single point of contact for access and submission for the research community to the breadth of ice core data sets. The need for a single point of contact for all ice core data was called for at the Spring 2000 Ice Core Working Group meeting in Denver. The design of the gateway allows for the continuation of valuable discipline-specific expertise and program-centric activities at the data centers, but utilizes web technology to provide a single point of entry for users. This poster describes existing and planned roles of the key ice core data management groups and technical issues such as common variable names, metadata, and quality control. We seek feedback from the ice core community regarding the Ice Core Data Gateway.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMPP43D1513H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMPP43D1513H"><span id="translatedtitle">Terrestrial biomarkers in the sediment of the East Sea (Japan Sea) since the MIS 11: implications for paleoproductivity and paleoclimatic changes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hyun, S.; Suh, Y. J.; Woo, K. S.; Ikehara, M.</p> <p>2014-12-01</p> <p>Terrestrial biomarkers such as n-alkanes and cholesterol were analyzed to infer the variations of paleoproductivity and the corresponding <span class="hlt">paleoclimatologic</span> information from the sediment of the Korean Plateau, East Sea (Japan Sea) since the Marine Isotope Stage (MIS) 11 (ca. 400 ka). Previous studies of SST variation have shown that glacial-interglacial scale changes were quite variable with the maximum range of 26oC in MIS 7, and the minimum range of 12oC during MIS 2 and 6. The distribution of terrestrial n-alkanes signatures is characterized by the occurrence of high odd number frequency with a minor contribution of specific compound (nC27 only). Average Chain Length (ACL) and Carbon Preferences Index (CPI), both of which are derived from n-alkane combination, show similar shifting between glacial and interglacial periods. This suggests that paleovegetation communities had been changed in responding to <span class="hlt">paleoclimatological</span> variations, and the input amount of terrestrial compound was strongly linked with <span class="hlt">paleoclimatologic</span> changes. In particular, depleted values of δ13Corg during MIS 2, 8 and 10 were coincident with lower nitrogen isotope values indicating local paleoceanographic effects such as paleoproductivity changes. Decoupling between δ13Corg and δ15Norg during MIS 1, 3, 5, 7 and coupling of the two during MIS 8 and 11 can be observed, which appear to be interpreted as local productivity changes. In particular, high abundance of cholesterol and C21 n-alkanes, which were derived from diatom, increased during interglacial periods. Therefore, alkenones, SST and n-alkanes signatures coincide with δ13Corg and δ15Norg variations during glacial-interglacial cycles and further strongly associated with cholesterol abundance suggesting that the paleoenvironmental conditions in East Sea during glacial-interglacial periods were sensitive not only to global climate changes but also to local paleceanographic variations. Surface water circulation around the Korea</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006QSRv...25.1850G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006QSRv...25.1850G"><span id="translatedtitle">Stable hydrogen-isotope ratios in beetle chitin: preliminary European data and re-interpretation of North American data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gröcke, Darren R.; Schimmelmann, Arndt; Elias, Scott; Miller, Randall F.</p> <p>2006-08-01</p> <p>Beetle exoskeletons contain chitin, a poly amino-sugar that is biosynthesized incorporating hydrogen isotopes from diet and water. As the stable isotope ratios D/H (or 2H/ 1H, expressed as δ D values) of precipitation and diet are jointly influenced by climate, the biochemically recorded hydrogen-isotope ratio in fossil beetle exoskeleton has the potential to be used for paleoclimatic reconstruction. New δ D data from modern beetles are presented as a preliminary database for Europe, with a re-evaluation of earlier North American data. We present correlated matrices of δ D values in modern beetle chitin and modern precipitation to demonstrate the concept. We review the pertinent literature to highlight the history, utility, and likely future research directions for the use of chitin's stable isotopes in entomological <span class="hlt">paleoclimatology</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6064022','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6064022"><span id="translatedtitle">Colombian late cretaceous tropical planktonic foraminifera: Redressing the imbalance</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>McCarthy, L.D.</p> <p>1993-02-01</p> <p>Recent work involving Late Cretaceous planktonic foraminifera has concentrated on European and other areas in the Northern Hemisphere. Many of the biostratigraphical and evolutionary models reflect this geographical restriction and ignore earlier studies from tropical areas. In 1955 Rolando Gandolfi described many new species and subspecies from Colombia and provided a different view of the evolutionary development of planktonic foraminifera. A re-examination of the Gandolfi type collection using Scanning Electron Micrography (Environmental Chamber technique) integrated with Colombian well samples from onshore Guajira area, Middle and Upper Magdalena Valley and Putumayo Basin has given a new view into the evolutionary development of Late Cretaceous planktonic foraminifera. This has enabled a modified globigerine Late Cretaceous biostratigraphy to be constructed for Colombia. This work redresses the imbalance between studies of tropical and northern high latitude Late Cretaceous planktonic foraminifera and provides an insight into the paleoenvironmental and <span class="hlt">paleoclimatological</span> factors influencing the Colombian region at the time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/fs/2012/3021/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/fs/2012/3021/"><span id="translatedtitle">Devils Hole, Nevada--A Primer</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Landwehr, Jurate M.; Winograd, Isaac J.</p> <p>2012-01-01</p> <p>This fact sheet summarizes the multifaceted research of the U.S. Geological Survey—published in diverse outlets—that focuses on the subaqueous cavern Devils Hole in Nevada. Questions addressed in the fact sheet are: What is Devils Hole? Why is Devils Hole of interest to paleoclimatologists? How was the isotopic record from the Devils Hole vein calcite dated? What paleoclimate phenomena are recorded by the Devils Hole stable isotopic time series? Where can one find the isotopic records? What contributions has Devils Hole research made to the field of <span class="hlt">paleoclimatology</span>, paleohydrology, and geochemistry? What does Devils Hole reveal about how long we can expect the present interglaciation to last? What are some practical applications of the Devils Hole findings? Why is Devils Hole of interest to zoologists?</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840017153','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840017153"><span id="translatedtitle">Modeling glacial climates</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>North, G. R.; Crowley, T. J.</p> <p>1984-01-01</p> <p>Mathematical climate modelling has matured as a discipline to the point that it is useful in <span class="hlt">paleoclimatology</span>. As an example a new two dimensional energy balance model is described and applied to several problems of current interest. The model includes the seasonal cycle and the detailed land-sea geographical distribution. By examining the changes in the seasonal cycle when external perturbations are forced upon the climate system it is possible to construct hypotheses about the origin of midlatitude ice sheets and polar ice caps. In particular the model predicts a rather sudden potential for glaciation over large areas when the Earth's orbital elements are only slightly altered. Similarly, the drift of continents or the change of atmospheric carbon dioxide over geological time induces radical changes in continental ice cover. With the advance of computer technology and improved understanding of the individual components of the climate system, these ideas will be tested in far more realistic models in the near future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850023287&hterms=Continental+Drift&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2528Continental%2BDrift%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850023287&hterms=Continental+Drift&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2528Continental%2BDrift%2529"><span id="translatedtitle">Regional magnetic anomaly constraints on continental rifting</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vonfrese, R. R. B.; Hinze, W. J.; Olivier, R.; Bentley, C. R.</p> <p>1985-01-01</p> <p>Radially polarized MAGSAT anomalies of North and South America, Europe, Africa, India, Australia and Antarctica demonstrate remarkably detailed correlation of regional magnetic lithospheric sources across rifted margins when plotted on a reconstruction of Pangea. These major magnetic features apparently preserve their integrity until a superimposed metamorphoric event alters the magnitude and pattern of the anomalies. The longevity of continental scale magnetic anomalies contrasts markedly with that of regional gravity anomalies which tend to reflect predominantly isostatic adjustments associated with neo-tectonism. First observed as a result of NASA's magnetic satellite programs, these anomalies provide new and fundamental constraints on the geologic evolution and dynamics of the continents and oceans. Accordingly, satellite magnetic observations provide a further tool for investigating continental drift to compliment other lines of evidence in <span class="hlt">paleoclimatology</span>, paleontology, paleomagnetism, and studies of the radiometric ages and geometric fit of the continents.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001Sci...292.2310R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001Sci...292.2310R"><span id="translatedtitle">Paleobotanical Evidence for Near Present-Day Levels of Atmospheric CO2 During Part of the Tertiary</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Royer, Dana L.; Wing, Scott L.; Beerling, David J.; Jolley, David W.; Koch, Paul L.; Hickey, Leo J.; Berner, Robert A.</p> <p>2001-06-01</p> <p>Understanding the link between the greenhouse gas carbon dioxide (CO2) and Earth's temperature underpins much of <span class="hlt">paleoclimatology</span> and our predictions of future global warming. Here, we use the inverse relationship between leaf stomatal indices and the partial pressure of CO2 in modern Ginkgo biloba and Metasequoia glyptostroboides to develop a CO2 reconstruction based on fossil Ginkgo and Metasequoia cuticles for the middle Paleocene to early Eocene and middle Miocene. Our reconstruction indicates that CO2 remained between 300 and 450 parts per million by volume for these intervals with the exception of a single high estimate near the Paleocene/Eocene boundary. These results suggest that factors in addition to CO2 are required to explain these past intervals of global warmth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20576882','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20576882"><span id="translatedtitle">The last glacial termination.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Denton, G H; Anderson, R F; Toggweiler, J R; Edwards, R L; Schaefer, J M; Putnam, A E</p> <p>2010-06-25</p> <p>A major puzzle of <span class="hlt">paleoclimatology</span> is why, after a long interval of cooling climate, each late Quaternary ice age ended with a relatively short warming leg called a termination. We here offer a comprehensive hypothesis of how Earth emerged from the last global ice age. A prerequisite was the growth of very large Northern Hemisphere ice sheets, whose subsequent collapse created stadial conditions that disrupted global patterns of ocean and atmospheric circulation. The Southern Hemisphere westerlies shifted poleward during each northern stadial, producing pulses of ocean upwelling and warming that together accounted for much of the termination in the Southern Ocean and Antarctica. Rising atmospheric CO2 during southern upwelling pulses augmented warming during the last termination in both polar hemispheres. PMID:20576882</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993EOSTr..74..250J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993EOSTr..74..250J"><span id="translatedtitle">IDEAL Symposium on the East African Lakes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Johnson, T. C.; Kelts, K.; Lehman, J. T.; Wuest, A.</p> <p></p> <p>A vast array of interdisciplinary problems presented by the African Great Lakes were highlighted at the International Symposium on the Limnology, Climatology and <span class="hlt">Paleoclimatology</span> of the East African Lakes, organized by the International Decade for the East African Lakes (IDEAL) February 17-21 in Jinja, Uganda. Approximately 125 scientists attended from North America, Europe, Africa, and New Zealand. Jinja is located on the northern shore of Lake Victoria at the head-waters of the Nile and is the site of the host institution for the symposium, the Uganda Freshwater Fisheries Research Organization (UFFRO). The conveners of the symposium were Tom Johnson of Duke University, George Kitaka of UNESCO-ROSTA, and Eric Odada of the University of Nairobi.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ISPAnIII4...17G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ISPAnIII4...17G&link_type=ABSTRACT"><span id="translatedtitle">Comparative Analysis of Global Digital Elevation Models and Ultra-Prominent Mountain Peaks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grohmann, Carlos H.</p> <p>2016-06-01</p> <p>Global Digital Elevation Models (GDEMs) are datasets of vital importance for regional-scale analysis in areas such as geomorphology, [<span class="hlt">paleo]climatology</span>, oceanography and biodiversity. In this work I present a comparative assessment of the datasets ETOPO1 (1' resolution), GTOPO30, GLOBE, SRTM30 PLUS, GMTED2010 and ACE2 (30") against the altitude of the world's ultra prominent peaks. GDEMs' elevations show an expected tendency of underestimating the peak's altitude, but differences reach 3,500 m. None of the GDEMs captures the full range of elevation on Earth and they do not represent well the altitude of the most prominent peaks. Some of these problems could be addressed with the release of NASADEM, but the smoothing effect caused by moving-window resampling can only be tackled by using new techniques, such as scale-adaptative kernels and curvature-based terrain generalisation.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/214858','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/214858"><span id="translatedtitle">Molecular and isotopic composition of lipids in modern and fossil bivalve shells: Records of paleoenvironmental change?</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>CoBabe, E.A.</p> <p>1995-12-31</p> <p>Suites of lipids residing in situ in modern and fossil bivalve shells offer new possibilities for the study of paleoecology and <span class="hlt">paleoclimatology</span>. Distributions of carbon isotopic compositions of modem shell lipids suggests that many of these compounds, including alkanes, sterols, fatty acids, ketones and phytadienes, are derived from the bivalves and not directly from the surrounding environment. The occurrence of fatty acids in modem and fossil shell material opens up the possibility that saturation levels of these compounds may be used as paleothermometers. To date, the utility of fatty acids in paleoclimate studies has been limited because of the swift breakdown of these compounds in sediment. However, initial results indicate that fatty acids in bivalve shells retain their original structure for at least several million years. Comparison of modem bivalve shell fatty acids from tropical, temperate and polar nearshore marine systems will be presented, along with analogous fossil data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4376705','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4376705"><span id="translatedtitle">Changes in the Radiocarbon Reservoir Age in Lake Xingyun, Southwestern China during the Holocene</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhou, Aifeng; He, Yuxin; Wu, Duo; Zhang, Xiaonan; Zhang, Can; Liu, Zhonghui; Yu, Junqing</p> <p>2015-01-01</p> <p>Chronology is a necessary component of <span class="hlt">paleoclimatology</span>. Radiocarbon dating plays a central role in determining the ages of geological samples younger than ca. 50 ka BP. However, there are many limitations for its application, including radiocarbon reservoir effects, which may cause incorrect chronology in many lakes. Here we demonstrate temporal changes in the radiocarbon reservoir age of Lake Xingyun, Southwestern China, where radiocarbon ages based on bulk organic matter have been reported in previous studies. Our new radiocarbon ages, determined from terrestrial plant macrofossils suggest that the radiocarbon reservoir age changed from 960 to 2200 years during the last 8500 cal a BP years. These changes to the reservoir effect were associated with inputs from either pre-aged organic carbon or 14C-depleted hard water in Lake Xingyun caused by hydrological change in the lake system. The radiocarbon reservoir age may in return be a good indicator for the carbon source in lake ecosystems and depositional environment. PMID:25815508</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EOSTr..93...92H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EOSTr..93...92H"><span id="translatedtitle">AGU climate scientists visit Capitol Hill</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hankin, Erik</p> <p>2012-02-01</p> <p>On 1 February 2012, AGU teamed with 11 other scientific societies to bring 29 scientists researching various aspects of climate change to Washington, D. C., for the second annual Climate Science Day on Capitol Hill. The participants represented a wide range of expertise, from meteorology to agriculture, <span class="hlt">paleoclimatology</span> to statistics, but all spoke to the reality of climate change as demonstrated in their scientific research. With Congress debating environmental regulations and energy policy amid tight fiscal pressures, it is critical that lawmakers have access to the best climate science to help guide policy decisions. The scientists met with legislators and their staff to discuss the importance of climate science for their districts and the nation and offered their expertise as an ongoing resource to the legislators.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1984nyjw.book.....W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1984nyjw.book.....W"><span id="translatedtitle">The evolving continents /2nd revised and enlarged edition/</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Windley, B. F.</p> <p></p> <p>The earth's history is traced through the tectonic evolution of the continental crust from the very beginning of the geological record, rather than by studying the stratigraphy of a particular area. The topics addressed include: Archean granulite-gneiss belts; Archean greenstone belts; crustal evolution in the Archean; early to mid-Proterozoic basic ultrabasic intrusion, basins, and belts; mid-Proterozoic anorogenic magmatism and abortive rifting; mid-late Proterozoic basins, dykes, glaciations, and life forms; late Proterozoic mobile belts; and crustal evolution in the Proterozoic. Also considered are: paleomagnetism and continental drift; <span class="hlt">paleoclimatology</span> and the fossil record; Caledonian-Appalachian fold belt; the Hercynian fold belt; Pangaea and its breakup; plate tectonics and sea-floor spreading; island arcs; continental margin orogenic belts; the Western Americas; the Alpine fold belt; the Himalayas; and the evolving continents.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008EOSTr..89..164C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008EOSTr..89..164C"><span id="translatedtitle">Ostracodology-Linking Bio- and Geosciences: Proceedings of the 15th International Symposium on Ostracoda, Berlin, 2005</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cronin, Thomas M.</p> <p>2008-04-01</p> <p>If you want to know about the ``paradox of sex'' or why a tiny crustacean prefers spinach over brussels sprouts, then read this book. Ostracodes are a class of small crustaceans of 33,000 known living and extinct species and many more yet to be described. They are notable for their application to <span class="hlt">paleoclimatology</span> and paleoenvironmental reconstruction-as described by J. Holmes and A. Chivas in the 2002 AGU Geophysical Monograph Series volume 131. In addition, they can make the evolutionary claim to the oldest proven male animal, a 435-million-year-old Silurian fossil from England called Colymbosathon ecplecticos (D. J. Siveter et al., Science, 302, 1749-1751, 2003).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25815508','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25815508"><span id="translatedtitle">Changes in the radiocarbon reservoir age in Lake Xingyun, Southwestern China during the Holocene.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhou, Aifeng; He, Yuxin; Wu, Duo; Zhang, Xiaonan; Zhang, Can; Liu, Zhonghui; Yu, Junqing</p> <p>2015-01-01</p> <p>Chronology is a necessary component of <span class="hlt">paleoclimatology</span>. Radiocarbon dating plays a central role in determining the ages of geological samples younger than ca. 50 ka BP. However, there are many limitations for its application, including radiocarbon reservoir effects, which may cause incorrect chronology in many lakes. Here we demonstrate temporal changes in the radiocarbon reservoir age of Lake Xingyun, Southwestern China, where radiocarbon ages based on bulk organic matter have been reported in previous studies. Our new radiocarbon ages, determined from terrestrial plant macrofossils suggest that the radiocarbon reservoir age changed from 960 to 2200 years during the last 8500 cal a BP years. These changes to the reservoir effect were associated with inputs from either pre-aged organic carbon or 14C-depleted hard water in Lake Xingyun caused by hydrological change in the lake system. The radiocarbon reservoir age may in return be a good indicator for the carbon source in lake ecosystems and depositional environment. PMID:25815508</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70014147','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70014147"><span id="translatedtitle">Sedimentary biomarker and isotopic indicators of the paleoclimatic history of the Walker Lake basin, western Nevada</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Meyers, P.A.; Benson, L.V.</p> <p>1988-01-01</p> <p>Walker Lake, a terminal saline lake in western Nevada, has experienced major fluctuations in its water level due to changes in the regional climate during Quaternary times. As part of a <span class="hlt">paleo-climatological</span> study of western Nevada, we have investigated organic matter ??13C and C/N values and lipid biomarker contents of sediments deposited at various periods over the past 150 thousand years of lake history. Surficial sediments from two cross-lake transects contain mostly lake-derived organic matter. Diagenetic losses of organic matter are evident in deeper sediments, and the proportion of aquatic and terrigenous organic materials changes in response to variations in preservational factors. Source identification of organic matter is complicated by the probability that Walker Lake has experienced desiccation at various times in its history which impacts the degree of preservation of organic substances. ?? 1988.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.5597H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.5597H"><span id="translatedtitle">SST and terrestrial n-alkanes records in sediment of the Korean Plateau, East Sea (Japan Sea) during the last 400 kyr: Paleoceanographic and paleoclimatic implications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hyun, Sangmin; Suh, Yean Jee; Kim, Jin Kyung</p> <p>2014-05-01</p> <p>SST variation was reconstructed using alkenones and their variation was compared with terrestrial n-alkanes signature from the sediment of the Korean Plateau, East Sea (Japan Sea) during the last 400 ka. SST variation showed glacial-interglacial time scale variation with a maximum temperature of 26 oC in MIS 7, and a minimum of 12 oC at MIS 2 and 6. The distribution of terrestrial n-alkanes signatures is characterized by the occurrence of high odd number predominance in most samples, however minor dominance of a specific compound (nC27 only) was the additional characteristic.bAverage Chain Length (ACL) and Carbon Preferences Index (ICP), derived from n-alkane distributions, showed a similar shifting between glacial-interglacial time-scale. This suggests that paleovegetation communities changed in response to <span class="hlt">paleoclimatological</span> variations, and the input of terrestrial compound is strongly linked with <span class="hlt">paleoclimatology</span>. In the previous work, isotopic composition of δ13C and δ15N of organic matter showed extreme temporal variation since MIS 11 suggesting influx of a large amount of terrestrial organic matters from the neighboring continent during MIS 2, 8 and 10. In particular, depleted values of δ13C during MIS 2, 8 and 10 were coincident with lower nitrogen isotope values indicating local paleoceanographic effects such as paleoproductivity changes. Decoupling of δ13C and δ15N during MIS 1, 3, 5, and 7, and coupling of the two during MIS 8 and 11 is observed, which can be interpreted as local productivity changes. The alkenones SST and n-alkanes signature coincided with carbon and nitrogen isotope variation in terms of glacial-interglacial time scale suggesting that the paleoenvironments in the East Sea is sensitive to the global climate changes associated with not only orbital-scale glacial-interglacial variations but also local paleceanographic variations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMIN23B1731W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMIN23B1731W&link_type=ABSTRACT"><span id="translatedtitle">Community-Supported Data Repositories in Paleobiology: A 'Middle Tail' Between the Geoscientific and Informatics Communities</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Williams, J. W.; Ashworth, A. C.; Betancourt, J. L.; Bills, B.; Blois, J.; Booth, R.; Buckland, P.; Charles, D.; Curry, B. B.; Goring, S. J.; Davis, E.; Grimm, E. C.; Graham, R. W.; Smith, A. J.</p> <p>2015-12-01</p> <p>Community-supported data repositories (CSDRs) in paleoecology and <span class="hlt">paleoclimatology</span> have a decades-long tradition and serve multiple critical scientific needs. CSDRs facilitate synthetic large-scale scientific research by providing open-access and curated data that employ community-supported metadata and data standards. CSDRs serve as a 'middle tail' or boundary organization between information scientists and the long-tail community of individual geoscientists collecting and analyzing paleoecological data. Over the past decades, a distributed network of CSDRs has emerged, each serving a particular suite of data and research communities, e.g. Neotoma Paleoecology Database, Paleobiology Database, International Tree Ring Database, NOAA NCEI for <span class="hlt">Paleoclimatology</span>, Morphobank, iDigPaleo, and Integrated Earth Data Alliance. Recently, these groups have organized into a common Paleobiology Data Consortium dedicated to improving interoperability and sharing best practices and protocols. The Neotoma Paleoecology Database offers one example of an active and growing CSDR, designed to facilitate research into ecological and evolutionary dynamics during recent past global change. Neotoma combines a centralized database structure with distributed scientific governance via multiple virtual constituent data working groups. The Neotoma data model is flexible and can accommodate a variety of paleoecological proxies from many depositional contests. Data input into Neotoma is done by trained Data Stewards, drawn from their communities. Neotoma data can be searched, viewed, and returned to users through multiple interfaces, including the interactive Neotoma Explorer map interface, REST-ful Application Programming Interfaces (APIs), the neotoma R package, and the Tilia stratigraphic software. Neotoma is governed by geoscientists and provides community engagement through training workshops for data contributors, stewards, and users. Neotoma is engaged in the Paleobiological Data Consortium</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMPP34A..04F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMPP34A..04F&link_type=ABSTRACT"><span id="translatedtitle">Can Convergent Cross Mapping Untangle Idiosyncratic Speleothem Proxy Records to Reveal the Structure of Shared Climate Forcing?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frappier, A. E.</p> <p>2015-12-01</p> <p>Rapid growth and development of speleothem <span class="hlt">paleoclimatology</span> has generated diverse and important new terrestrial paleoenvironmental proxy records that increasingly illuminate both the enormous potential and great complexity of cave proxy systems and speleothem data. Speleothem records commonly exhibit complex covariation patterns between proxy variables (i.e. carbon and oxygen isotopes, various trace element concentrations and ratios, stratigraphic characteristics, growth rates, etc...). Such covariation patterns frequently change sign and magnitude over time, and often show periods without significant correlation that alternate with times with strongly coupled behavior. These patterns are evident when comparing records between sites and stalagmites, and even within a single stalagmite. Instability in covariation patterns and low long-term correlations both limit our confidence in applying speleothems proxy transfer functions over long time periods. Are these complex covariation patterns meaningful or merely mirages? When two speleothem records show the same result, replication is considered by the community to be evidence that both records are highly sensitive to a common climate signal and are thus reliable proxies for that climate signal. Signals derived from a single speleothem dataset could be noise, and thus of limited value until it is validated by the replication test. Are speleothems naturally idiosyncratic and noisy? Must all speleothem records be duplicated to establish reliability? I consider whether Convergent Cross Mapping (CCM) may offer a fruitful approach to these problems. CCM is a powerful statistical tool developed in George Sugihara's lab for complex dynamical systems that tests the direction of causality and strength of forcing among multiple time-series variables. I apply CCM to speleothem timeseries records to 1) reconstruct the underlying state climate variable of interest over time (in this case, precipitation), and 2) determine the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMPP51A2282S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMPP51A2282S&link_type=ABSTRACT"><span id="translatedtitle">Using Thecamoebians to Reconstruct 1300 Years of Limnological Change at Crystal Lake, Southern California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Silveira, E.; Palermo, J. A.; Kirby, M. E.</p> <p>2015-12-01</p> <p>Thecamoebians are microscopic unicellar organisms that live in freshwater lakes and produce tests—or shells—that are morphologically distinct to each species. The population distribution of thecamoebian species within a lake can reveal such lake dynamics as trophic status, temperature, and acidity. Crystal Lake is a small alpine lake located in the San Gabriel Mountains of the coastal southwest United States. This project's objective is to reconstruct a 1300 yr paleolimnological record for Crystal Lake using thecamoebian assemblages. The latter reconstruction will be examined in the context of <span class="hlt">paleoclimatological</span> interpretations from the same core (Palermo et al., 2015) to determine to what extent - if any - changes in thecamoebian assemblages respond to, and record, <span class="hlt">paleoclimatological</span> changes such as the Medieval Climate Anomaly and the Little Ice Age. Core CLPC14-1 was extracted from Crystal Lake's depocenter in May 2014. Grain size, magnetic susceptibility, and LOI 550°C and 950°C were measured at 1 cm contiguous intervals; additionally, C:N ratios and C and N isotopic analyses were measured every 2 cm (Palermo, 2015). Thecamoebian assemblages were analyzed in five modern surface samples, as well as throughout the core at 2 cm intervals (aligning with the other analyses performed). Statistical analysis was performed to determine significant patterns within the assemblages. Eleven AMS 14C dates of discrete organic matter (i.e. wood or charcoal) were used to generate an age model using Beacon v2.2; for the past 200 years, age control is based on correlation to Rothenberg et al. (2010) core ages (Palermo, 2015).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFMGP31B1067F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFMGP31B1067F&link_type=ABSTRACT"><span id="translatedtitle">Defense of GAD during the 1950s and early 1960s</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frankel, H. R.</p> <p>2012-12-01</p> <p>Paleomagnetists favoring continental offered empirical and theoretical support for the GAD hypothesis. Initial support came from the discovery that the mean directions of rock units, regardless of polarity, laid down back through the Upper Tertiary centered on the rotational pole. Armed with Fisher's statistics, Hospers (1951, 1953) found that the mean direction of the NRM of Icelandic lava flows back through the Miocene better agreed with the GAD field than with the present field. Similarly, Campbell and Runcorn (1956), Creer (1956), and Irving and Green (1957) respectively found that the natural remanent magnetization of Late Tertiary Columbia River basalts, Quaternary basalts of Argentina, and Late Cenozoic New Volcanics of Victoria supported the hypothesis. If significant continental drift or "true" polar wander has occurred, paleomagnetic data alone cannot determine if the axial element of the GAD hypothesis holds earlier than Late Tertiary. Extending the GAD hypothesis back in time requires an approach involving a means independent of paleomagnetism for determining past latitudes. Irving was the first to realize that the <span class="hlt">paleoclimatology</span> would work. If the GAD hypothesis holds, then paleolatitudes based on paleomagnetism and <span class="hlt">paleoclimatology</span> should agree. Irving (1956) found that, except for the Squantum Tillite, the paleomagnetically and paleoclimatically determined paleolatitudes for Europe, North America, India, and Tasmania were in agreement. He concluded that the magnetic and rotational axes have coincided since the Paleozoic. Blackett (1961) also compared paleoclimatic and paleomagnetic data-sets. Irving and Briden (1962, 1964) further appealed to <span class="hlt">paleoclimatology</span> to defend the hypothesis. Determining the paleolatitude spectra for several paleoclimatic indicators, they found the present latitude of fossil instances inconsistent with the latitude of modern instances while their paleomagnetically determined paleolatitudes, which assumed the GAD hypothesis</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.8616H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.8616H"><span id="translatedtitle">Paleoproductivity vs. influx of terrestrial biomarker in sediment from the Korean Plateau, East Sea (Japan Sea) since the MIS 11</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hyun, Sangmin; Suh, Yean Jee; Ikehara, Miroru</p> <p>2015-04-01</p> <p>A piston core collected from the Korean Plateau, East Sea (Japan Sea) of Korea was conducted in terms of variations in paleoproductivity and influx of terrestrial biomarker. The distribution of terrestrial n-alkanes signatures is characterized by the occurrence of high odd number frequency with a minor contribution of specific compound (nC27 only). Average Chain Length (ACL) and Carbon Preferences Index (CPI), both of which are derived from n-alkane combination, show similar shifting between glacial and interglacial periods. Previous studies of SST variation have shown that glacial-interglacial scale changes were quite variable with the maximum range of 26oC in MIS 7, and the minimum range of 12oC during MIS 2 and 6. Therefore, paleovegetation communities had been changed in responding to <span class="hlt">paleoclimatological</span> variations, and the input amount of terrestrial compound was strongly linked with <span class="hlt">paleoclimatologic</span> changes. The isotopic composition of δ13C and δ15N of organic matter, which showed extreme temporal variation since MIS 11, indicates the influx of large amount of terrestrial organic matter from the neighboring terrestrial environments during MIS 2, 8 and 10. In particular, depleted values of δ13Corg during MIS 2, 8 and 10 were coincident with lower nitrogen isotope values indicating local paleoceanographic effects such as paleoproductivity changes. Decoupling between δ13Corg and δ15Norg during MIS 1, 3, 5, 7 and coupling of the two during MIS 8 and 11 can be observed, which appear to be interpreted as local productivity changes. In particular, high abundance of cholesterol and C21 n-alkanes, which were derived from diatom, increased during interglacial periods. Therefore, alkenones, SST and n-alkanes signatures coincide with δ13Corg and δ15Norg variations during glacial-interglacial cycles and further strongly associated with cholesterol abundance suggesting that the paleoenvironmental conditions in East Sea during glacial-interglacial periods were</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23029053','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23029053"><span id="translatedtitle">Regional scale high resolution δ18O prediction in precipitation using MODIS EVI.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chan, Wei-Ping; Yuan, Hsiao-Wei; Huang, Cho-Ying; Wang, Chung-Ho; Lin, Shou-De; Lo, Yi-Chen; Huang, Bo-Wen; Hatch, Kent A; Shiu, Hau-Jie; You, Cheng-Feng; Chang, Yuan-Mou; Shen, Sheng-Feng</p> <p>2012-01-01</p> <p>The natural variation in stable water isotope ratio data, also known as water isoscape, is a spatiotemporal fingerprint and a powerful natural tracer that has been widely applied in disciplines as diverse as hydrology, <span class="hlt">paleoclimatology</span>, ecology and forensic investigation. Although much effort has been devoted to developing a predictive water isoscape model, it remains a central challenge for scientists to generate high accuracy, fine scale spatiotemporal water isoscape prediction. Here we develop a novel approach of using the MODIS-EVI (the Moderate Resolution Imagining Spectroradiometer-Enhanced Vegetation Index), to predict δ(18)O in precipitation at the regional scale. Using a structural equation model, we show that the EVI and precipitated δ(18)O are highly correlated and thus the EVI is a good predictor of precipitated δ(18)O. We then test the predictability of our EVI-δ(18)O model and demonstrate that our approach can provide high accuracy with fine spatial (250×250 m) and temporal (16 days) scale δ(18)O predictions (annual and monthly predictabilities [r] are 0.96 and 0.80, respectively). We conclude the merging of the EVI and δ(18)O in precipitation can greatly extend the spatial and temporal data availability and thus enhance the applicability for both the EVI and water isoscape. PMID:23029053</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.U31C0024Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.U31C0024Z"><span id="translatedtitle">Antarctica Research in the Polar Research Center of China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Z.; Li, Y.; Liu, S.; Cole-Dai, J.</p> <p>2003-12-01</p> <p>The Polar Research Center of China (PRCC) was established in the early 1990s (formerly Polar Research Institute of China) to serve as the leading national organization for Antarctica-related research in China. Current research areas of center staff scientists include glaciology and <span class="hlt">paleoclimatology</span>, upper atmospheric physics, polar and marine biology, and oceanagrphy. In addition to its own active research, PRCC on behalf of the China Antarctic and Arctic Administration coordinates and provides logistical support to Antarctica research activities by all Chinese scientists. The center organizes and manages the annual Chinese Research Expedition to Antarctica with participation from many other national and academic institutions. In its first decade of existence, PRCC has accumulated valuable experience in conducting and facilitating research in Antarctica, particularly in the areas of logistic support for field programs, staffing and managing the two permanent stations in Antarctica (Great Wall and Zhongshan). The successful operation of the Chinese Antarctica research program has benefitted from generous assistance from several more established national (for example, Australia, Japan and the United States) Antarctica programs and from frequent contact with international colleagues working on Antarctica research. Among the many issues and problems frequently encountered in the last decade are: (1) The scale of research activities is often seriously constrained by logistic capabilities and funding; (2) Limited computer network and library resources hamper speedy and timely access to relevant international scientific literature; (3) Acquisition of high quality scientific (field and laboratory) equipment and special supplies can be limited by funding and access to suppliers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMPP13C..02D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMPP13C..02D"><span id="translatedtitle">How does ice sheet loading affect ocean flow around Antarctica?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dijkstra, H. A.; Rugenstein, M. A.; Stocchi, P.; von der Heydt, A. S.</p> <p>2012-12-01</p> <p>Interactions and dynamical feedbacks between ocean circulation, heat and atmospheric moisture transport, ice sheet evolution, and Glacial Isostatic Adjustment (GIA) are overlooked issues in <span class="hlt">paleoclimatology</span>. Here we will present first results on how ocean flows were possibly affected by the glaciation of Antarctica across the Eocene-Oligocene Transition (~ 34 Ma) through GIA and bathymetry variations. GIA-induced gravitationally self-consistent bathymetry variations are determined by solving the Sea Level Equation (SLE), which describes the time dependent shape of (i) the solid Earth and (ii) the equipotential surface of gravity. Since the ocean circulation equations are defined relative to the equipotential surface of gravity, only bathymetry variations can influence ocean flows, although the sea surface slope will also change through time due to gravitational attraction. We use the Hallberg Isopycnal Model under late Eocene conditions to calculate equilibrium ocean flows in a domain in which the bathymetry evolves under ice loading according to the SLE. The bathymetric effects of the glaciation of Antarctica lead to substantial spatial changes in ocean flows, and close to the coast, the flow even reverses direction. Volume transports through the Drake Passage and Tasman Seaway adjust to the new bathymetry. The results indicate that GIA-induced ocean flow variations alone may have had an impact on sedimentation and erosion patterns, the repositioning of fronts, ocean heat transport and grounding line and ice sheet stability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70021561','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70021561"><span id="translatedtitle">Foraminiferal faunal estimates of paleotemperature: Circumventing the no-analog problem yields cool ice age tropics</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Mix, A.C.; Morey, A.E.; Pisias, N.G.; Hostetler, S.W.</p> <p>1999-01-01</p> <p>The sensitivity of the tropics to climate change, particularly the amplitude of glacial-to-interglacial changes in sea surface temperature (SST), is one of the great controversies in <span class="hlt">paleoclimatology</span>. Here we reassess faunal estimates of ice age SSTs, focusing on the problem of no-analog planktonic foraminiferal assemblages in the equatorial oceans that confounds both classical transfer function and modern analog methods. A new calibration strategy developed here, which uses past variability of species to define robust faunal assemblages, solves the no-analog problem and reveals ice age cooling of 5??to 6??C in the equatorial current systems of the Atlantic and eastern Pacific Oceans. Classical transfer functions underestimated temperature changes in some areas of the tropical oceans because core-top assemblages misrepresented the ice age faunal assemblages. Our finding is consistent with some geochemical estimates and model predictions of greater ice age cooling in the tropics than was inferred by Climate: Long-Range Investigation, Mapping, and Prediction (CLIMAP) [1981] and thus may help to resolve a long-standing controversy. Our new foraminiferal transfer function suggests that such cooling was limited to the equatorial current systems, however, and supports CLIMAP's inference of stability of the subtropical gyre centers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012QSRv...56...11C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012QSRv...56...11C"><span id="translatedtitle">Rapid sea-level rise</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cronin, Thomas M.</p> <p>2012-11-01</p> <p>Several global and regional factors contribute to observed sea-level change along any particular coast. Global processes include changes in ocean mass (glacio-eustasy from ice melt), ocean volume (steric effects), viscoelastic land movements (glacioisostatic adjustment GIA), and changes in terrestrial water storage. Regional processes, often connected to steric and glacial changes, include changes in ocean circulation (Meridional Overturning Circulation [MOC]), glacial melting, local GIA, regional subsidence and others. Paleoclimate, instrumental and modeling studies show that combinations of these factors can cause relatively rapid rates of sea-level rise exceeding 3 mm yr-1 over various timescales along particular coasts. This paper discusses patterns and causes of sea-level rise with emphasis on <span class="hlt">paleoclimatological</span> records. It then addresses the hypothesis of late Holocene (pre-20th century) sea-level stability in light of paleoclimatic evidence, notably from reconstructions of sea-surface temperature and glacial activity, for significant climate and sea-level variability during this time. The practical difficulties of assessing regional sea-level (SL) patterns at submillennial timescales will be discussed using an example from the eastern United States.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002AGUFMED11B0040M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002AGUFMED11B0040M&link_type=ABSTRACT"><span id="translatedtitle">The Development and Evaluation of the Climate Time Line Information Tool</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McCaffrey, M. S.; Kowal, D.; Eakin, C. M.</p> <p>2002-12-01</p> <p>The Climate Time Line Information Tool or CTL (http://www.ngdc.noaa.gov/paleo/ctl) has been prototyped as a digital educational tool for conveying fundamental climatic processes and their human dimension for diverse audiences. Using a powers of ten approach to temporal scaling, the CTL website was developed through a CIRES Innovative Research Grant by Mark McCaffrey at the National Climatic Data Center's <span class="hlt">Paleoclimatology</span> Program and Dan Kowal at the National Geophysical Data Center. CTL was specifcally designed as an interdisciplinary tool for conveying information about weather and climatic processes, such as the diurnal, annual and orbital cycles and ENSO. Moreover, the web site explores potential connections between climatic variability and human development over the past 100,000 years. Evaluation of the prototype examined issues of usability and navigation of the site as well as how its content and framework served the needs of undergraduate, middle and high school students, geoscience educators, and climate experts. The development and evaluation of the Climate Time Line provide a case study for other geoscience researchers and educators on: i) how objectives were set by developers; ii) how evaluators were involved in assessing the prototype; iii) the variety of evaluative methods available to test the viability of the product; and iv) how results from the evaluation can be used to finalize the prototype.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.V11C2075B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.V11C2075B"><span id="translatedtitle">Toward speleothem tephrochronology: Experimental simulation of volcanic ash weathering in a karst setting</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baldwin, M.; Frappier, A. B.</p> <p>2008-12-01</p> <p>Speleothem studies are beginning to identify various geochemical signatures of tephra layers related to known explosive volcanic events. Frappier previously analyzed the trace elemental composition of a recent calcite stalagmite from Belize. A large increase in diverse trace elemental impurities was found to correspond to the regional ashfall from the April 1982 V.E.I. 5 eruption of El Chichon in Chiapas, Mexico. To establish a reliable speleothem tephrochronological absolute dating tool, researchers must develop a mechanistic understanding of the processes that govern the deposition, preservation, and geochemical composition of speleothem tephra marker horizons. In tracking the processes between ashfall and speleothem deposition, it is particularly vital to characterize the initial tephra weathering products and their modification in karst soils and carbonate seepage waters. Here we present results from an experimental simulation of early stage weathering of trachyandesitic tephra. Volcanic ash from the 1982 El Chichon eruption was obtained from the Smithsonian Institution for leaching experiments. Using a factorial design, aliquots of a weak nitric acid solution were exposed to fine (less than 64 micron) and bulk ash samples, both alone and in the presence of karst soil from Belize. Mixtures were filtered to separate the solid fraction from the leachate, and ICP-MS analysis was performed on the suite of leachate samples at Boston University. We discuss the experimental results with respect to the geochemical composition of the tephra and observed stalagmite cryptotephra layer. We also address implications for development of an absolute dating tool for Quaternary geochronolgy and <span class="hlt">paleoclimatology</span> of speleothems.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013Geomo.200...59D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013Geomo.200...59D&link_type=ABSTRACT"><span id="translatedtitle">The role of fieldwork in rock decay research: Case studies from the fringe</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dorn, Ronald I.; Gordon, Steven J.; Allen, Casey D.; Cerveny, Niccole; Dixon, John C.; Groom, Kaelin M.; Hall, Kevin; Harrison, Emma; Mol, Lisa; Paradise, Thomas R.; Sumner, Paul; Thompson, Tyler; Turkington, Alice V.</p> <p>2013-10-01</p> <p>Researchers exploring rock decay hail from chemistry, engineering, geography, geology, <span class="hlt">paleoclimatology</span>, soil science, and other disciplines and use laboratory, microscopic, theoretical, and field-based strategies. We illustrate here how the tradition of fieldwork forms the core knowledge of rock decay and continues to build on the classic research of Blackwelder, Bryan, Gilbert, Jutson, King, Linton, Twidale, and von Humboldt. While development of nonfield-based investigation has contributed substantially to our understanding of processes, the wide range of environments, stone types, and climatic variability encountered raises issues of temporal and spatial scales too complex to fit into attempts at universal modeling. Although nonfield methods are immensely useful for understanding overarching processes, they can miss subtle differences in factors that ultimately shape rock surfaces. We, therefore, illustrate here how the tradition of fieldwork continues today alongside laboratory and computer-based investigations and contributes to our understanding of rock decay processes. This includes the contribution of fieldwork to the learning process of undergraduates, the calculation of activation energies of plagioclase and olivine dissolution, the high Arctic, the discovery of a new global carbon sink, the influence of plant roots, an analysis of the need for protocols, tafoni development, stone monuments, and rock coatings. These compiled vignettes argue that, despite revolutionary advances in instrumentation, rock decay research must remain firmly footed in the field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFMIN43A3682S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFMIN43A3682S&link_type=ABSTRACT"><span id="translatedtitle">STEPPE: Supporting collaborative research and education on Earth's deep-time sedimentary crust.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, D. M.</p> <p>2014-12-01</p> <p>STEPPE—Sedimentary geology, Time, Environment, Paleontology, Paleoclimate, and Energy—is a National Science Foundation supported consortium whose mission is to promote multidisciplinary research and education on Earth's deep-time sedimentary crust. Deep-time sedimentary crust research includes many specialty areas—biology, geography, ecology, paleontology, sedimentary geology, stratigraphy, geochronology, <span class="hlt">paleoclimatology</span>, sedimentary geochemistry, and more. In fact, the diversity of disciplines and size of the community (roughly one-third of Earth-science faculty in US universities) itself has been a barrier to the formation of collaborative, multidisciplinary teams in the past. STEPPE has been working to support new research synergies and the development of infrastructure that will encourage the community to think about the big problems that need to be solved and facilitate the formation of collaborative research teams to tackle these problems. Toward this end, STEPPE is providing opportunities for workshops, working groups and professional development training sessions, web-hosting and database services and an online collaboration platform that facilitates interaction among participants, the sharing of documentation and workflows and an ability to push news and reports to group participants and beyond using social media tools. As such, STEPPE is working to provide an interactive space that will serve as both a gathering place and clearinghouse for information, allowing for broader integration of research and education across all STEPPE-related sub disciplines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70004512','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70004512"><span id="translatedtitle">Testing coral-based tropical cyclone reconstructions: An example from Puerto Rico</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kilbourne, K. Halimeda; Moyer, Ryan P.; Quinn, Terrence M.; Grottoli, Andrea G.</p> <p>2011-01-01</p> <p>Complimenting modern records of tropical cyclone activity with longer historical and <span class="hlt">paleoclimatological</span> records would increase our understanding of natural tropical cyclone variability on decadal to centennial time scales. Tropical cyclones produce large amounts of precipitation with significantly lower δ18O values than normal precipitation, and hence may be geochemically identifiable as negative δ18O anomalies in marine carbonate δ18O records. This study investigates the usefulness of coral skeletal δ18O as a means of reconstructing past tropical cyclone events. Isotopic modeling of rainfall mixing with seawater shows that detecting an isotopic signal from a tropical cyclone in a coral requires a salinity of ~ 33 psu at the time of coral growth, but this threshold is dependent on the isotopic composition of both fresh and saline end-members. A comparison between coral δ18O and historical records of tropical cyclone activity, river discharge, and precipitation from multiple sites in Puerto Rico shows that tropical cyclones are not distinguishable in the coral record from normal rainfall using this approach at these sites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5925885','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5925885"><span id="translatedtitle">Carboniferous coal swamp vegetation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Phillips, T.L.; Peppers, R.A.; DiMichele, W.A.</p> <p>1984-01-01</p> <p>The Carboniferous Period was one of considerable change on the Earth. The volume explores these changes by using plant morphology and paleoecology to develop the relationship between plant evolution and the derived coal sources. Both are interrelated by the regional and stratigraphic trends in paleoecology and <span class="hlt">paleoclimatology</span>. The book is divided into three sections dealing with geology, plant morphology including palynology, and paleoecology. In Section I, the paleogeography, geologic settings of major coal basins, coal resources, coal-ball origins and occurrences, and the sources of paleobotanical information are presented with biostratigraphic correlations of Europe and the United States. Section II emphasizes plant morphology as form and structure provide the means of identifying plants and, in turn, establishing development, size, habit, reproductive biology, environmental parameters, and evolutionary change. Quantitative abundances and stratigraphic ranges of plants and spores are compared and summarized. Lastly, Section III integrates coal-ball peats and coal-spore floras as complementary sources for the quantitative analyses of coal-swamp vegetation in relation to climate and coal. The local and regional swamp studies are interfaced and basinal geology and depositional interpretations in a stratigraphic succession.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015CliPD..11.3897T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015CliPD..11.3897T"><span id="translatedtitle">The MIS 5 palaeoenvironmental record in the SE Mediterranean coast of the Iberian Peninsula (Río Antas, Almería, Spain)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Torres, T.; Ortiz, J. E.; Blázquez, A. M.; Ruiz Zapata, B.; Gil, M. J.; Martín, T.; Sánchez-Palencia, Y.</p> <p>2015-08-01</p> <p>Landwards of a MIS5 bar, a borehole core (SRA) was analyzed to establish the relationship between the lagoonal record and the raised beach deposits in the surroundings of the Antas river mouth and to reconstruct the Pleistocene palaeoenvironmental evolution of the southern Mediterranean coast of the Iberian Peninsula. 63 samples were recovered for amino acid racemization dating, 86 samples for sedimentological and paleontological determination, 37 samples for pollen identification and 54 for biomarker analysis. AAR revealed that the borehole record contains MIS11, MIS6 and MIS5 deposits, the latter extensively represented. During the end of MIS6 and MIS5, a sand barrier developed and created a shallow lagoon with alternating terrestrial inputs this process being common in other Mediterranean realms. Litho- and biofacies allowed the identification of distinct paleoenvironments through time, with the presence of a lagoonal environment alternating with alluvial fan progradation. Biomarkers indicated constant input from terrestrial plants, together with variable development of aquatic macrophytes. The palynological content allowed the reconstruction of the <span class="hlt">paleoclimatological</span> conditions during MIS6 and 5, with evidence of seven scenarios characterized by alternating arid and relatively humid conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1710179G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1710179G"><span id="translatedtitle">Lake sediment records of late Holocene monsoon variability in western Nepal (preliminary results)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ghazoui, Zakaria; Bertrand, Sebastien; Sachse, Dirk; Nomade, Jerome; Prasad Gajurel, Ananta; van der Beek, Peter</p> <p>2015-04-01</p> <p>In Nepal, high altitude <span class="hlt">paleoclimatological</span> and limnological studies face many logistical challenges due to remoteness, accessibility, and altitude of potential lake sampling sites. Therefore, paleolimnological investigations in the Nepalese Himalaya remain scarce, and most of our understanding of past Indian Summer Monsoon (ISM) variability relies on a low-density network of speleothems and ice cores. Here we report preliminary new data from three high-altitude lakes in the Nepal Himalaya. In order to improve our understanding of climate variability in western Nepal during the late Holocene three lakes were investigated and sampled in autumn 2014: Rara Lake, Mugu District; Phoksundo Lake, Dolpa District; Dhumba Lake, Mustang District. The sediment cores are being studied using a multi-proxy approach combining radiocarbon, 210Pb and 137Cs chronologies, physical properties (Geotek multi-sensor core logger), grain size (Malvern Mastersizer 3000) inorganic geochemistry (major and selected trace elements by ICP-AES and ITRAX XRF core scanning), bulk organic geochemistry (C, N concentrations and stable isotopes) and hydrogen isotopic composition of leaf wax long-chain n-alkanes (δDwax). These sediment records will provide important new insights into the late-Holocene variability of the Indian Summer Monsoon in Nepal, including the recent latitudinal shift of the rainbelt due to climate change in the 20th and 21st centuries.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011AGUFMED21C0591D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011AGUFMED21C0591D&link_type=ABSTRACT"><span id="translatedtitle">Investigating Climate Change Issues With Web-Based Geospatial Inquiry Activities</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dempsey, C.; Bodzin, A. M.; Sahagian, D. L.; Anastasio, D. J.; Peffer, T.; Cirucci, L.</p> <p>2011-12-01</p> <p>In the Environmental Literacy and Inquiry middle school Climate Change curriculum we focus on essential climate literacy principles with an emphasis on weather and climate, Earth system energy balance, greenhouse gases, <span class="hlt">paleoclimatology</span>, and how human activities influence climate change (http://www.ei.lehigh.edu/eli/cc/). It incorporates a related set of a framework and design principles to provide guidance for the development of the geospatial technology-integrated Earth and environmental science curriculum materials. Students use virtual globes, Web-based tools including an interactive carbon calculator and geologic timeline, and inquiry-based lab activities to investigate climate change topics. The curriculum includes educative curriculum materials that are designed to promote and support teachers' learning of important climate change content and issues, geospatial pedagogical content knowledge, and geographic spatial thinking. The curriculum includes baseline instructional guidance for teachers and provides implementation and adaptation guidance for teaching with diverse learners including low-level readers, English language learners and students with disabilities. In the curriculum, students use geospatial technology tools including Google Earth with embedded spatial data to investigate global temperature changes, areas affected by climate change, evidence of climate change, and the effects of sea level rise on the existing landscape. We conducted a designed-based research implementation study with urban middle school students. Findings showed that the use of the Climate Change curriculum showed significant improvement in urban middle school students' understanding of climate change concepts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..1111632M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..1111632M"><span id="translatedtitle">Stable isotopic composition of bivalve shell organic matrix: Mytilus edulis collected along the Scheldt estuary</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mas, R.; Claeys, P.; Keppens, E.; Dehairs, F.</p> <p>2009-04-01</p> <p>Bivalve shells are biostructures composed of a mineral and an organic phase. For <span class="hlt">paleoclimatology</span> applications, the mineral part (carbonates) is most widely studied. In contrast, understanding of the composition and the proxy-function of the organic matrix is much less developed. The quantity of organic matrix in shells is relatively small compared to the mineral phase (a few wt %) and the biochemical composition is quite complex, consisting mainly of sugars and proteins. Lipids, which represent a small fraction of the organic matrix, are rather poorly known. We studied the potential of stable isotope composition (C, N, H) of bulk organic matrix and specific lipid compounds of Mytilis edulis shells, as environmental and climatic proxies, with special focus on the effects due to changing salinity. Mytilus specimens were collected along the salinity gradient of the Scheldt estuary (The Netherlands) and we analysed the isotopic composition of the organic matrix and associated specific lipid compounds and related these to averaged physico-chemical characteristics of the water, in particular salinity. We discuss these relationships in the light of their usefulness as proxies for reconstructing past environmental conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18403210','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18403210"><span id="translatedtitle">Principles of demineralization: modern strategies for the isolation of organic frameworks. Part I. Common definitions and history.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ehrlich, Hermann; Koutsoukos, Petros G; Demadis, Konstantinos D; Pokrovsky, Oleg S</p> <p>2008-12-01</p> <p>In contrast to biomineralization phenomena, that are among the most widely studied topics in modern material and earth science and biomedicine, much less is systematized on modern view of demineralization. Biomineralized structures and tissues are composites, containing a biologically produced organic matrix and nano- or microscale amorphous or crystalline minerals. Demineralization is the process of removing the inorganic part, or the biominerals, that takes place in nature via either physiological or pathological pathways in organisms. In vitro demineralization processes, used to obtain mechanistic information, consist in the isolation of the mineral phase of the composite biomaterials from the organic matrix. Physiological and pathological demineralization include, for example, bone resorption mediated by osteoclasts. Bioerosion, a more general term for the process of deterioration of the composite biomaterials represents chemical deterioration of the organic and mineral phase followed by biological attack of the composite by microorganisms and enzymes. Bioerosional organisms are represented by endolithic cyanobacteria, fungi, algae, plants, sponges, phoronids and polychaetes, mollusks, fish and echinoids. In the history of demineralization studies, the driving force was based on problems of human health, mostly dental caries. In this paper we summarize and integrate a number of events, discoveries, milestone papers and books on different aspect of demineralization during the last 400 years. Overall, demineralization is a rapidly growing and challenging aspect of various scientific disciplines such as astrobiology, <span class="hlt">paleoclimatology</span>, geomedicine, archaeology, geobiology, dentistry, histology, biotechnology, and others to mention just a few. PMID:18403210</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMPP51D..06Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMPP51D..06Y"><span id="translatedtitle">Sea level record obtained from submerged the Great Barrier Reef coral reefs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yokoyama, Y.; Esat, T. M.; Thompson, W. G.; Thomas, A. L.; Webster, J.; Miyairi, Y.; Matsuzaki, H.; Okuno, J.; Fallon, S.; Braga, J.; Humblet, M.; Iryu, Y.; Potts, D. C.</p> <p>2013-12-01</p> <p>The last glacial is an interesting time in climate history. The growth and decay of large northern hemisphere ice sheets acting in harmony with major changes in ocean circulation amplified climate variations and resulted in severe and rapid climate swings throughout this time. The variability is not limited to climate but includes rapid, large scale changes in sea level recorded by tropical corals (eg., Yokoyama and Esat, 2011 Oceanography). Research done in the last decade using corals provides a better picture of the climate system, though only a few samples older than 15 ka are available. The Integrated Ocean Drilling Program (IODP) Expedition 325 drilled 34 holes across 17 sites in the Great Barrier Reef, Australia to recover fossil coral reef deposits. We recovered reef materials from water depth to 126 m that ranged in age from 9,000 years to older than 30,000 years ago covering several <span class="hlt">paleoclimatologically</span> important events, including the Last Glacial Maximum. Two transects separated more than 600 km apart show an identical sea-level history thereby verifying the reliability of the records. Radiometrically dated corals and coralline algae indicate periods of rapid sea-level fluctuation at this time, likely due to complex interactions between ocean currents and ice sheets of the North Atlantic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010E%26PSL.297...57L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010E%26PSL.297...57L"><span id="translatedtitle">Application of the authigenic 10Be/ 9Be dating method to continental sediments: Reconstruction of the Mio-Pleistocene sedimentary sequence in the early hominid fossiliferous areas of the northern Chad Basin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lebatard, Anne-Elisabeth; Bourlès, Didier L.; Braucher, Régis; Arnold, Maurice; Duringer, Philippe; Jolivet, Marc; Moussa, Abderamane; Deschamps, Pierre; Roquin, Claude; Carcaillet, Julien; Schuster, Mathieu; Lihoreau, Fabrice; Likius, Andossa; Mackaye, Hassan Taisso; Vignaud, Patrick; Brunet, Michel</p> <p>2010-08-01</p> <p>The concentrations of atmospheric cosmogenic 10Be normalized to the solubilized fraction of its stable isotope 9Be have been measured in the authigenic phase leached from silicated continental sediments deposited since the upper Miocene in the northern Chad Basin. This method is validated by the systematic congruence with the biochronological estimations based on the fossil mammal evolutive degree of faunal assemblages. The fifty-five authigenic 10Be/ 9Be ages obtained along 12 logs distributed along two West-East cross sections that encompass best representative Mio-Pliocene outcrops including paleontological sites show a systematic stratigraphic decrease when considering all studied sedimentary facies extending from the Pleistocene up to 8 Ma and allow performing geologic correlations otherwise impossible in the studied area. The resulting global sequence evidences and temporally specifies the succession of the main paleoenvironments that have developed in this region since the Miocene. Under the special conditions encountered in the northern Chad Basin, this study demonstrates that the authigenic 10Be/ 9Be ratio may be used as a dating tool of continental sedimentary deposits from 1 to 8 Ma. The half-life of 10Be theoretically allowing dating up to 14 Ma, it may have fundamental implications on important field research such as <span class="hlt">paleoclimatology</span> and, through the dating of fossiliferous deposits in paleontology and paleoanthropology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=17871','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=17871"><span id="translatedtitle">Replicated evolution of trophic specializations in an endemic cichlid fish lineage from Lake Tanganyika</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rüber, Lukas; Verheyen, Erik; Meyer, Axel</p> <p>1999-01-01</p> <p>The current phylogenetic hypothesis for the endemic Lake Tanganyika cichlid fishes of the tribe Eretmodini is based solely on morphology and suggests that more complex trophic morphologies derived only once from a less specialized ancestral condition. A molecular phylogeny of eretmodine cichlids based on partial mitochondrial DNA cytochrome b and control-region sequences was used to reconstruct the evolutionary sequence of trophic adaptations and to test alternative models of morphological divergence. The six mitochondrial lineages found disagree with the current taxonomy and the morphology-based phylogeny. Mitochondrial lineages with similar trophic morphologies are not grouped monophyletically but are typically more closely related to lineages with different trophic phenotypes currently assigned to other genera. Our results indicate multiple independent origins of similar trophic specializations in these cichlids. A pattern of repeated divergent morphological evolution becomes apparent when the phylogeography of the mitochondrial haplotypes is analyzed in the context of the geological and <span class="hlt">paleoclimatological</span> history of Lake Tanganyika. In more than one instance within Lake Tanganyika, similar morphological divergence of dentitional traits occurred in sympatric species pairs. Possibly, resource-based divergent selective regimes led to resource partitioning and brought about similar trophic morphologies independently and repeatedly. PMID:10468591</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003GMS...137.....D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003GMS...137.....D"><span id="translatedtitle">Earth's Climate and Orbital Eccentricity: The Marine Isotope Stage 11 Question</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Droxler, André W.; Poore, Richard Z.; Burckle, Lloyd H.</p> <p></p> <p>Weather bureaus around the world have accumulated daily historical records of atmospheric conditions for more than a century to help forecast meteorological conditions three to five days ahead. To gain insight into the impact of possible future climate warming and constrain predictive models for a warm future, climatologists are seeking <span class="hlt">paleoclimatologic</span> and paleoceanographic records from the most recent intervals in the Quaternary when conditions were demonstrably warmer than they are today. In the past 2.5 My, Earth climate has oscillated from cold (glacial) to warm (interglacial) intervals. We currently live in a warm interval, the Holocene, during which the climate has remained relatively constant for about 10 ky. Because the Holocene is nearly as long now as the previous interglacial, scientists have projected the possibly imminent onset of another ice age, excluding human intervention. Whether or not this will occur is a question of some significance, and has sparked debate. Finding an analogue to our current status in other recent interglacials offers substantive aid in clarifying the question just mentioned, and others, concerning global climate change over varying geologic time periods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003GMS...137D...7D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003GMS...137D...7D"><span id="translatedtitle">Preface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Droxler, André W.; Poore, Richard Z.; Burckle, Lloyd H.</p> <p></p> <p>Weather bureaus around the world have accumulated daily historical records of atmospheric conditions for more than a century to help forecast meteorological conditions three to five days ahead. To gain insight into the impact of possible future climate warming and constrain predictive models for a warm future, climatologists are seeking <span class="hlt">paleoclimatologic</span> and paleoceanographic records from the most recent intervals in the Quaternary when conditions were demonstrably warmer than they are today. In the past 2.5 My, Earth climate has oscillated from cold (glacial) to warm (interglacial) intervals. We currently live in a warm interval, the Holocene, during which the climate has remained relatively constant for about 10 ky. Because the Holocene is nearly as long now as the previous interglacial, scientists have projected the possibly imminent onset of another ice age, excluding human intervention. Whether or not this will occur is a question of some significance, and has sparked debate. Finding an analogue to our current status in other recent interglacials offers substantive aid in clarifying the question just mentioned, and others, concerning global climate change over varying geologic time periods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4477698','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4477698"><span id="translatedtitle">A TEX86 surface sediment database and extended Bayesian calibration</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Tierney, Jessica E; Tingley, Martin P</p> <p>2015-01-01</p> <p>Quantitative estimates of past temperature changes are a cornerstone of <span class="hlt">paleoclimatology</span>. For a number of marine sediment-based proxies, the accuracy and precision of past temperature reconstructions depends on a spatial calibration of modern surface sediment measurements to overlying water temperatures. Here, we present a database of 1095 surface sediment measurements of TEX86, a temperature proxy based on the relative cyclization of marine archaeal glycerol dialkyl glycerol tetraether (GDGT) lipids. The dataset is archived in a machine-readable format with geospatial information, fractional abundances of lipids (if available), and metadata. We use this new database to update surface and subsurface temperature calibration models for TEX86 and demonstrate the applicability of the TEX86 proxy to past temperature prediction. The TEX86 database confirms that surface sediment GDGT distribution has a strong relationship to temperature, which accounts for over 70% of the variance in the data. Future efforts, made possible by the data presented here, will seek to identify variables with secondary relationships to GDGT distributions, such as archaeal community composition. PMID:26110065</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005AGUFMED34A..06A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005AGUFMED34A..06A&link_type=ABSTRACT"><span id="translatedtitle">The Role of Internet Paleo Perspective Overviews in Making Data About Past Climate and Environmental Change More Accessible</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anderson, D. M.; Bauer, B. A.; Gille, E. P.; Gross, W. S.; Hartman, M. A.; Shah, A. M.; Woodhouse, C. A.</p> <p>2005-12-01</p> <p>The cornerstone of scientific discovery is the peer-reviewed journal article, yet for non-specialists these articles can be difficult to appreciate. Scientific writing and the sheer number of articles published each month compound the problem. At the World Data Center for <span class="hlt">Paleoclimatology</span>, a primary goal is to make published scientific results more accessible to non-specialists. In partnership with scientists, we have created Paleo Perspectives, online essays that provide an introduction to the scientific literature on a topic, background needed to appreciate the results, figures with detailed captions, photographs, short movies and visualizations, summaries, glossaries, direct links to the data, and links to additional information. The power and flexibility of the Internet enables us to provide and update this rich array of material. We have produced three paleo perspectives (global warming, drought, abrupt climate change), with a fourth in review (arctic climate variability). Web statistics indicate these are some of the Data Center`s most often-used web pages (more so for hot topics such as global warming), and awards and accolades indicate that the content is appreciated and on-target. Review by scientists assures the accuracy of the presentations, and newly-contributed data provide material for updates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3446878','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3446878"><span id="translatedtitle">Regional Scale High Resolution δ18O Prediction in Precipitation Using MODIS EVI</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Huang, Cho-Ying; Wang, Chung-Ho; Lin, Shou-De; Lo, Yi-Chen; Huang, Bo-Wen; Hatch, Kent A.; Shiu, Hau-Jie; You, Cheng-Feng; Chang, Yuan-Mou; Shen, Sheng-Feng</p> <p>2012-01-01</p> <p>The natural variation in stable water isotope ratio data, also known as water isoscape, is a spatiotemporal fingerprint and a powerful natural tracer that has been widely applied in disciplines as diverse as hydrology, <span class="hlt">paleoclimatology</span>, ecology and forensic investigation. Although much effort has been devoted to developing a predictive water isoscape model, it remains a central challenge for scientists to generate high accuracy, fine scale spatiotemporal water isoscape prediction. Here we develop a novel approach of using the MODIS-EVI (the Moderate Resolution Imagining Spectroradiometer-Enhanced Vegetation Index), to predict δ18O in precipitation at the regional scale. Using a structural equation model, we show that the EVI and precipitated δ18O are highly correlated and thus the EVI is a good predictor of precipitated δ18O. We then test the predictability of our EVI-δ18O model and demonstrate that our approach can provide high accuracy with fine spatial (250×250 m) and temporal (16 days) scale δ18O predictions (annual and monthly predictabilities [r] are 0.96 and 0.80, respectively). We conclude the merging of the EVI and δ18O in precipitation can greatly extend the spatial and temporal data availability and thus enhance the applicability for both the EVI and water isoscape. PMID:23029053</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.H31E0281G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.H31E0281G"><span id="translatedtitle">Extreme Drought Conditions in the Rio Grande/Bravo Basin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gutiérrez, F.; Dracup, J. A.</p> <p>2001-12-01</p> <p>The Treaty of February 3, 1944 entitled "Utilization of Waters of the Colorado and Tijuana Rivers and of the Rio Grande" between the U.S. and Mexico regulates the distribution of flows of the rivers between these two countries. The treaty is based on hydrological data available up to 1944. Using new (historical and <span class="hlt">paleoclimatological</span>) data, the water balance presented in the Treaty is re-examinated and the 431,721,000 m3/year allocation for USA during "extreme drought conditions" is re-evaluated. The authors define "extreme drought conditions" for this basin and a hydrological drought analysis is carried out using a streamflow simulation model. The analysis is complemented with an analysis of the effects of the El Niño - Southern Oscillation and the Pacific Decadal Oscillation on precipitation and streamflow. The results of this research will be applicable to potential changes in the current water resources management policies on the basin. Given the social, economical and political importance of this basin, the findings of this research potentially will have significant impacts. This research is founded by the NSF fund SAHRA (Science and Technology Center to study and promote the "Sustainability of Water Resources in Semi-Arid Regions" at the University of Arizona).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMPP53C2377M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMPP53C2377M"><span id="translatedtitle">Comparison and Significance of Two Different Organic Paleotemperature Reconstructions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ma, X.; Zhang, H.; He, J.; Ruan, Y.; Dong, L.; Wang, H.; Li, L.</p> <p>2015-12-01</p> <p>Temperature is a basic parameter in the study of <span class="hlt">paleoclimatology</span> and paleoceanography. In the present study, two organic geochemical proxies, UK'37 and TEX86 were used for the sea surface temperature reconstruction in the site MD123434 (18°49.84'N,116°18.89'E, water depth 2995m) in northern South China Sea. On the whole, the two reconstructed temperature correlated well with each other, reflecting low temperature in the last glacial and high in the Holocene. Nevertheless, detailed comparison illustrated relatively higher reconstructed temperature by the UK'37 method than that in TEX86 proxy, with a range of 23.0℃ to 27.8℃ and 18.9℃to 29.5℃ for UK'37 and TEX86 proxy respectively. The average temperature discrepancy (ΔT) between the two temperature proxies is ~3℃ during the last glacial and ~0℃ during the Holocene, which cannot be fully attributed to calculation errors. The offset between these two proxies may be caused by the different living water depths of the source organisms: haptophyte and Thaumarchaeota for the UK'37 and TEX86 respectively. The terrestrial GDGTs input and the different calibration equations on the TEX86 may possibly also contribute to the discrepancy. Meanwhile, growth seasonalities between the two source organisms cannot be ignored either.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EOSTr..94R.132S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EOSTr..94R.132S"><span id="translatedtitle">Tree ring records capture long-term memory in climate systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schultz, Colin</p> <p>2013-03-01</p> <p>Measuring tree rings is a mainstay technique for estimating ancient climatic conditions, with a tree's year-by-year growth reflecting changes in precipitation and temperature. In some cases, <span class="hlt">paleoclimatological</span> records compiled from tree ring measurements can stretch for thousands of years. Based on recent research, climatologists have found that hydrological and other systems have long-term memory. Drawing on tree ring measurements compiled from across the continental United States, Bowers et al. sought to determine whether such long-term relationships are preserved in ring width measurements. The authors analyzed the Hurst parameter—a measure of long-term memory—of 697 different tree ring records that were collected from 10 tree species from locations across the United States. They found that though each tree species had a different mean value for its Hurst parameter, meaning that each species recorded long-term trends in the climate differently, they all fell within the range suggestive of their being able to properly represent long-term memory.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020002700','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020002700"><span id="translatedtitle">Obliquity Modulation of the Incoming Solar Radiation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Liu, Han-Shou; Smith, David E. (Technical Monitor)</p> <p>2001-01-01</p> <p>Based on a basic principle of orbital resonance, we have identified a huge deficit of solar radiation induced by the combined amplitude and frequency modulation of the Earth's obliquity as possibly the causal mechanism for ice age glaciation. Including this modulation effect on solar radiation, we have performed model simulations of climate change for the past 2 million years. Simulation results show that: (1) For the past 1 million years, temperature fluctuation cycles were dominated by a 100-Kyr period due to amplitude-frequency resonance effect of the obliquity; (2) From 2 to 1 million years ago, the amplitude-frequency interactions. of the obliquity were so weak that they were not able to stimulate a resonance effect on solar radiation; (3) Amplitude and frequency modulation analysis on solar radiation provides a series of resonance in the incoming solar radiation which may shift the glaciation cycles from 41-Kyr to 100-Kyr about 0.9 million years ago. These results are in good agreement with the marine and continental paleoclimate records. Thus, the proposed climate response to the combined amplitude and frequency modulation of the Earth's obliquity may be the key to understanding the glaciation puzzles in <span class="hlt">paleoclimatology</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70012178','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70012178"><span id="translatedtitle">Uranium-series dating of sediments from Searles Lake: Differences between continental and marine climate records</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bischoff, J.L.; Rosenbauer, R.J.; Smith, G.I.</p> <p>1985-01-01</p> <p>One of the major unresolved questions in Pleistocene <span class="hlt">paleoclimatology</span> has been whether continental climatic transitions are consistent with the glacial ??18O marine record. Searles Lake in California, now a dry salt pan, is underlain by sediment layers deposited in a succession of lakes whose levels and salinities have fluctuated in response to changes in climate over the last 3 ?? 106 years. Uranium-series dates on the salt beds range from 35 ?? 103 to 231 ?? 103 years. This range of dates allows identification of lake-sediment horizons that are time correlatives of the boundaries of marine isotope stages from the recent 3/4 boundary back to the 8/9 boundary. The 5/6 boundary coincided with a deepening of the lake, but the analogous 1/2 boundary coincided with desiccation. The 3/4, 4/5, 6/7, 7/8, and 8/9 boundaries correspond in age to horizons that record little or no change in sedimentation or climate. These hydrologic results demonstrate that the continental paleoclimate record at this mid-latitude site does not mimic the marine record.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17757864','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17757864"><span id="translatedtitle">Uranium-series dating of sediments from searles lake: differences between continental and marine climate records.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bischoff, J L; Rosenbauer, R J; Smith, G I</p> <p>1985-03-01</p> <p>One of the major unresolved questions in Pleistocene <span class="hlt">paleoclimatology</span> has been whether continental climatic transitions are consistent with the glacial delta(18)O marine record. Searles Lake in California, now a dry salt pan, is underlain by sediment layers deposited in a succession of lakes whose levels and salinities have fluctuated in response to changes in climate over the last 3 x 10(6) years. Uraniumseries dates on the salt beds range from 35 x 10(3) to 231x 10(3) years. This range of dates allows identification of lake-sediment horizons that are time correlatives of the boundaries of marine isotope stages from the recent 3/4 boundary back to the 8/9 boundary. The 5/6 boundary coincided with a deepening of the lake, but the analogous 1/2 boundary coincided with desiccation. The 3/4, 4/5, 6/7, 7/8, and 8/9 boundaries correspond in age to horizons that record little or no change in sedimentation or climate. These hydrologic results demonstrate that the continental paleoclimate record at this mid-latitude site does not mimic the marine record. PMID:17757864</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5267849','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5267849"><span id="translatedtitle">Bibliography of the paleontology and paleoecology of the Devonian-Mississippian black-shale sequence in North America</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Barron, L.S.; Ettensohn, F.R.</p> <p>1980-06-01</p> <p>The Devonian-Mississippian black-shale sequence is one of the most prominent and well-known stratigraphic horizons in the Paleozoic of the United States, yet the paleontology and its paleoecologic and paleoenvironmental implications are poorly known. This is in larger part related to the scarcity of fossils preserved in the shale - in terms of both diversity and abundance. Nonetheless, that biota which is preserved is well-known and much described, but there is little synthesis of this data. The first step in such a synthesis is the compilation of an inclusive bibliography such as this one. This bibliography contains 1193 entries covering all the major works dealing with Devonian-Mississippian black-shale paleontology and paleoecology in North America. Articles dealing with areas of peripheral interest, such as paleogeography, <span class="hlt">paleoclimatology</span>, ocean circulation and chemistry, and modern analogues, are also cited. In the index, the various genera, taxonomic groups, and other general topics are cross-referenced to the cited articles. It is hoped that this compilation will aid in the synthesis of paleontologic and paleoecologic data toward a better understanding of these unique rocks and their role as a source of energy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFMPP41E..06C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFMPP41E..06C"><span id="translatedtitle">Ostracode Mg/Ca Paleothermometry: Applications and Complications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cronin, T. M.; Dwyer, G. S.</p> <p>2007-12-01</p> <p>Ostracode (bivalved Crustacea) shell Mg/Ca paleothermometry has wide applicability in Cenozoic <span class="hlt">paleoclimatology</span> over 101 to 107 year timescales because they are commonly fossilized, live in freshwater, shallow- and deep-marine habitats, and grow by molting, which minimizes Mg/Ca variability due to ontogenetic variability. Two empirically derived Mg/Ca-temperature calibrations based on core top and culturing include one for the shallow marine, estuarine genus Loxoconcha (5 to 30°C) and another for deep-sea genus Krithe (<1 to 14°C). The former produced a temperature history for Chesapeake Bay for the last millennium, which has been intensively analyzed in the context of the hockey stick temperature curve. The latter produced evidence for decreased deep-sea temperature during glacial intervals and the first Atlantic-wide reconstruction of deep-sea temperature during the warm mid-Pliocene. In addition to temperature, however, factors such as host-water magnesium concentrations, salinity, intra-shell, intra-population, and interspecific variabilility, seasonality, biological factors (shell secretion rate), and post-mortem dissolution can contribute to scatter in calibration datasets and uncertainty in paleotemperature estimates. We will review these processes, present a new 2000 year Chesapeake temperature record, and discuss its relation to twentieth century climate change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007AGUFMPP54A..01B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007AGUFMPP54A..01B&link_type=ABSTRACT"><span id="translatedtitle">Whither Dendroclimatology?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bunn, A. G.; Lloyd, A. H.</p> <p>2007-12-01</p> <p>As in other fields of <span class="hlt">paleoclimatology</span>, uniformitarianism is the key principle in dendroclimatology. The assumption that the processes that form tree rings now are the same as those in the past is what allows climate to be reconstructed from tree rings. Recent years have seen declining ring widths in the northern high latitudes coincident with increasing temperatures despite being an ostensibly temperature limited environment. There are several factors that could play into this phenomenon. It could be that that more nuanced statistical or process models are needed to fully understand the climate | growth relationship. Or, there could be exogenous forcings (e.g., global dimming) that contribute to the shift in the climate | growth relationship, and that understanding the nature of those forcings is needed. What can this "divergence problem" tell us about tree growth and climate and does the apparent loss of sensitivity indicate a violation of the uniformity principle? We will present an analysis of simulated and real tree-ring data that attempts to answer these questions and show that while there are basic gaps in our understanding, the careful modeling of climate | growth relations and the proper attribution of error are keys to the making progress on the "divergence opportunity."</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26PSL.445...68L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26PSL.445...68L"><span id="translatedtitle">Deep water provenance and dynamics of the (de)glacial Atlantic meridional overturning circulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lippold, Jörg; Gutjahr, Marcus; Blaser, Patrick; Christner, Emanuel; de Carvalho Ferreira, Maria Luiza; Mulitza, Stefan; Christl, Marcus; Wombacher, Frank; Böhm, Evelyn; Antz, Benny; Cartapanis, Olivier; Vogel, Hendrik; Jaccard, Samuel L.</p> <p>2016-07-01</p> <p>Reconstructing past modes of ocean circulation is an essential task in <span class="hlt">paleoclimatology</span> and paleoceanography. To this end, we combine two sedimentary proxies, Nd isotopes (εNd) and the 231Pa/230Th ratio, both of which are not directly involved in the global carbon cycle, but allow the reconstruction of water mass provenance and provide information about the past strength of overturning circulation, respectively. In this study, combined 231Pa/230Th and εNd down-core profiles from six Atlantic Ocean sediment cores are presented. The data set is complemented by the two available combined data sets from the literature. From this we derive a comprehensive picture of spatial and temporal patterns and the dynamic changes of the Atlantic Meridional Overturning Circulation over the past ∼25 ka. Our results provide evidence for a consistent pattern of glacial/stadial advances of Southern Sourced Water along with a northward circulation mode for all cores in the deeper (>3000 m) Atlantic. Results from shallower core sites support an active overturning cell of shoaled Northern Sourced Water during the LGM and the subsequent deglaciation. Furthermore, we report evidence for a short-lived period of intensified AMOC in the early Holocene.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015BGD....1216979Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015BGD....1216979Z"><span id="translatedtitle">Aligning MIS5 proxy records from Lake Ohrid (FYROM) with independently dated Mediterranean archives: implications for core chronology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zanchetta, G.; Regattieri, E.; Giaccio, B.; Wagner, B.; Sulpizio, R.; Francke, A.; Vogel, L. H.; Sadori, L.; Masi, A.; Sinopoli, G.; Lacey, J. H.; Leng, M. L.; Leicher, N.</p> <p>2015-10-01</p> <p>The DEEP site sediment sequence obtained during the ICDP SCOPSCO project at Lake Ohrid was dated using tephrostratigraphic information, cyclostratigraphy, and orbital tuning through marine isotope record. Although this approach is suitable for the generation of a general chronological framework of the long succession, it is insufficient to resolve more detailed <span class="hlt">paleoclimatological</span> questions, such as leads and lags of climate events between marine and terrestrial records or between different regions. In this paper, we demonstrate how the use of different tie points can affect cyclostratigraphy and orbital tuning for the period between ca. 140 and 70 ka and how the results can be correlated with directly/indirectly radiometrically-dated Mediterranean marine and continental proxy records. The alternative age model obtained shows consistent differences with that proposed by Francke et al. (2015) for the same interval, in particular at the level of the MIS6-5e transition. According to this age model, different proxies from the DEEP site sediment record support an increase of temperatures between glacial to interglacial conditions, which is almost synchronous with a rapid increase in sea surface temperature observed in the western Mediterranean. The results show how important a detailed study of independent chronological tie points is for synchronizing different records and to highlight asynchronisms of climate events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFMPP51E1360K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFMPP51E1360K"><span id="translatedtitle">Solar vs. Tidal Forcing of Centennial to Decadal Scale Variability in Marine Sedimentary Records from the Western Antarctic Peninsula</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kirkwood, G.; Domack, E.; Brachfeld, S.</p> <p>2004-12-01</p> <p> and Whorf, 2000). We discuss these alternative forcing mechanisms with respect to: contrasts in regional processes of glacial marine sedimentation, the mechanism whereby the tidal or solar signal is transferred to the sediment column and possible cryptic stratigraphy of the Palmer Deep record (ie. missing time, Nederbragt and Thurow, 2002). Resolution of the correct forcing factor is critical to our ability to hind cast the last 100 years of paleoenvironmental data within these cores and hence to our attempts at recognizing an anthropogenic climate signal in the Antarctic Peninsula region. Howell, P. (2001), ARAND time series and spectral analysis package for the Macintosh, Brown University, IGBP PAGES/World Data Center for <span class="hlt">Paleoclimatology</span> Data Contribution Series #2001-044, NOAA/NGDC <span class="hlt">Paleoclimatology</span> Program, Boulder, Colo. Keeling, Charles D., and Timothy P. Whorf (2000), The 1,800-year oceanic tidal cycle: A possible cause of rapid climate change, Proc. Natl. Acad. Sci., 97 (8), 3814-3819. Nederbragt, A. J., and Thurow, J. (2002) Sediment color variation and annual accumulation rates in laminated Holocene sediments, Site 1098, Palmer Deep. In Barker, P. F., Camerlenghi, A., Acton, G. D., and Ramsay, A.T.S. (eds), Proc. ODP Sci. Results, 178: College Station TX (Ocean Drilling Program). Warner, Nathaniel R., and E. Domack (2002), Millennial-to decadal-scale paleoenvironmental change during the Holocene in the Palmer Deep, Antarctica, as recorded by particle size analysis, Paleoceanography, 17 (3), 8004, doi:10.1029/2000PA000602.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFMPP54A..08N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFMPP54A..08N"><span id="translatedtitle">Late Holocene Drought Record From Castor Lake, North-Central Washington State</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nelson, D. B.; Abbott, M. B.; Polissar, P. J.; Finney, B.</p> <p>2006-12-01</p> <p>), multi-taper method (MTM), and wavelet analysis reveal a significant 25 year periodicity in the early part of the record transitioning to a 50 year periodicity in the later part and persisting into modern times. The modern climate of Castor Lake is primarily influenced by changes in the northern Pacific Ocean, and the region has been shown to respond to global-scale patterns such as the Pacific Decadal Oscillation (PDO), and the Pacific/North America Pattern (PNA), for which several decadal-scale periods of oscillation have been identified. The dominant periodicity transition from 25 to 50 years in the Castor Lake grayscale record may thus reflect changes in one or more of these systems, or a change in the effects of their interactions on regional climate. 1. E. R. Cook, D. M. Meko, D. W. Stahle, M. K. Cleaveland, in Data Contribution Series # 2004-045 I. P. W. D. C. f. <span class="hlt">Paleoclimatology</span>, Ed. (NOAA/NGDC <span class="hlt">Paleoclimatology</span> Program, Boulder, CO, 2004).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFMPP11C2027G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFMPP11C2027G&link_type=ABSTRACT"><span id="translatedtitle">A 3D Earth orbit model; visualization and analysis of Milankovitch cycles and insolation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gilb, R. D.; Kostadinov, T. S.</p> <p>2012-12-01</p> <p>An astronomically precise and accurate Earth orbit graphical model, Earth orbit v2.0, is presented. The model offers 3D visualizations of Earth's orbital geometry, Milankovitch parameters and the ensuing insolation forcings. Prevalent paleoclimatic theories invoke Milankovitch cycles as a major forcing mechanism capable of shifting Earth's climate regimes on time scales of tens to hundreds of thousands of years. Variability of eccentricity (ellipticity of orbit), precession (longitude of perihelion) and obliquity (Earth's axial tilt) changes parameters such as amplitude of seasonal insolation, timing of seasons with respect to perihelion, and total annual insolation. Hays et al. (1976) demonstrated a strong link between Milankovitch cycles and <span class="hlt">paleoclimatological</span> records, which has been confirmed and expanded many times since (e.g. Berger et al., 1994; Berger et al., 2010). The complex interplay of several orbital parameters on various time scales makes assessment and visualization of Earth's orbit and spatio-temporal insolation variability challenging. It is difficult to appreciate the pivotal importance of Kepler's laws of planetary motion in controlling the effects of Milankovitch cycles on insolation patterns on various spatio-temporal scales. These factors also make Milankovitch theory difficult to teach effectively. The model allows substantial user control in a robust, yet intuitive and user-friendly graphical user interface (GUI) developed in Matlab. We present the user with a choice between Berger et al. (1978) and Laskar et al. (2004) astronomical solutions for eccentricity, obliquity and precession. Berger solutions span from -1 Myr to +1 Myr, while Laskar provides solutions from -101 Myr to +21 Myr since J2000. Users can also choose a "demo" mode which allows the three Milankovitch parameters to be varied independently of each other, so the user can isolate the effects of each on orbital geometry and insolation. For example, extreme eccentricity can be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMPP51A1930S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMPP51A1930S"><span id="translatedtitle">A comparison of high-resolution pollen-inferred climate data from central Minnesota, USA, to 19th century US military fort climate data and tree-ring inferred climate reconstructions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>St Jacques, J.; Cumming, B. F.; Sauchyn, D.; Vanstone, J. R.; Dickenson, J.; Smol, J. P.</p> <p>2013-12-01</p> <p>A vital component of <span class="hlt">paleoclimatology</span> is the validation of <span class="hlt">paleoclimatological</span> reconstructions. Unfortunately, there is scant instrumental data prior to the 20th century available for this. Hence, typically, we can only do long-term validation using other proxy-inferred climate reconstructions. Minnesota, USA, with its long military fort climate records beginning in 1820 and early dense network of climate stations, offers a rare opportunity for proxy validation. We compare a high-resolution (4-year), millennium-scale, pollen-inferred paleoclimate record derived from varved Lake Mina in central Minnesota to early military fort records and dendroclimatological records. When inferring a paleoclimate record from a pollen record, we rely upon the pollen-climate relationship being constant in time. However, massive human impacts have significantly altered vegetation; and the relationship between modern instrumental climate data and the modern pollen rain becomes altered from what it was in the past. In the Midwest, selective logging, fire suppression, deforestation and agriculture have strongly influenced the modern pollen rain since Euro-American settlement in the mid-1800s. We assess the signal distortion introduced by using the conventional method of modern post-settlement pollen and climate calibration sets to infer climate at Lake Mina from pre-settlement pollen data. Our first February and May temperature reconstructions are based on a pollen dataset contemporaneous with early settlement to which corresponding climate data from the earliest instrumental records has been added to produce a 'pre-settlement' calibration set. The second February and May temperature reconstructions are based on a conventional 'modern' pollen-climate dataset from core-top pollen samples and modern climate normals. The temperature reconstructions are then compared to the earliest instrumental records from Fort Snelling, Minnesota, and it is shown that the reconstructions based on the pre</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.5499V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.5499V"><span id="translatedtitle">Weathering and monsoonal evolution in the Eastern Himalayas since 13 Ma from detrital geochemistry, Kameng River Section, Arunachal Pradesh</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vögeli, Natalie; Van der Beek, Peter; Najman, Yani; Huyghe, Pascale</p> <p>2015-04-01</p> <p>The link between tectonics, erosion and climate has become an important subject to ongoing research in the last years (Clift et al. (2008), amongst others). The young Himalayan orogeny is the perfect laboratory for its study. The Neogene sedimentary foreland basin of the Himalaya contains a record of tectonics and paleoclimate since Miocene times, within the so called Siwalik Group. Therefore several sedimentary sections within the Himalayan foreland basin along strike in the Himalayan range have been dated and studied regarding exhumation rates, provenance and <span class="hlt">paleoclimatology</span> (e.g. Quade and Cerling, 1995; Ghosh et al., 2004; Sanyal et al., 2004; van der Beek et al., 2006). Lateral variations have been observed and changes in exhumation rate as well as climate change in the past especially the strengthening of the Asian summer monsoon is still debated. Several <span class="hlt">paleoclimatological</span> studies in the western Himalaya were conducted (Quade and Cerling, 1995; Najman et al., 2003; Huyghe et al., 2005), but the eastern part of the mountain range remains poorly studied. The Himalaya has a major influence on global and regional climate. The major force driving the evolution of this mountain belt is the India-Asia convergence, nevertheless it has been suggested that the monsoonal climate plays a major role for the erosion and relief pattern (Bookhagen and Burbank, 2006; Clift et al., 2008; Iaffaldano et al., 2011). Exhumation rates in the central Himalayas are more or less constant over last 13 Ma in the order of 1.8 km/myr, whereas exhumation rates in the eastern syntaxis increased post 3 Ma (Chirouze et al., 2013) to reach up to 10km/myr in the recent past. In this study we use a multidisciplinary approach in order to better understand the interplay of monsoon and weathering regime during the Mid Miocene to Pleistocene in the Himalaya. Therefore a sedimentary section in the eastern Himalaya was sampled. Pairs of fine and coarse grained sediment samples were taken in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70146188','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70146188"><span id="translatedtitle">Distinguishing seawater from geologic brine in saline coastal groundwater using radium-226; an example from the Sabkha of the UAE</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kraemer, Thomas F.; Wood, Warren W.; Sanford, Ward E.</p> <p>2014-01-01</p> <p>Sabkhat (Salt flats) are common geographic features of low-lying marine coastal areas that develop under hyper-arid climatic conditions. They are characterized by the presence of highly concentrated saline solutions and evaporitic minerals, and have been cited in the geologic literature as present-day representations of hyper-arid regional paleohydrogeology, <span class="hlt">paleoclimatology</span>, coastal processes, and sedimentation in the geologic record. It is therefore important that a correct understanding of the origin and development of these features be achieved. Knowledge of the source of solutes is an important first step in understanding these features. Historically, two theories have been advanced as to the main source of solutes in sabkha brines: an early concept entailing seawater as the obvious source, and a more recent and dynamic theory involving ascending geologic brine forced upward into the base of the sabkha by a regional hydraulic gradient in the underlying formations. Ra-226 could uniquely distinguish between these sources under certain circumstances, as it is typically present at elevated activity of hundreds to thousands of Bq/m3 (Becquerels per cubic meter) in subsurface formation brines; at exceedingly low activities in open ocean and coastal water; and not significantly supplied to water from recently formed marine sedimentary framework material. The coastal marine sabkha of the Emirate of Abu Dhabi was used to test this hypothesis. The distribution of Ra-226 in 70 samples of sabkha brine (mean: 700 Bq/m3), 7 samples of underlying deeper formation brine (mean: 3416 Bq/m3), the estimated value of seawater (< 16 Bq/m3) and an estimate of supply from sabkha sedimentary framework grains (<~6 Bq/m3) provide the first direct evidence that ascending geologic brine contributes significantly to the solutes of this sabkha system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1810307T&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1810307T&link_type=ABSTRACT"><span id="translatedtitle">Time averaging and stratigraphic disorder of molluscan assemblages in the Holocene sediments in the NE Adriatic (Piran)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tomasovych, Adam; Gallmetzer, Ivo; Haselmair, Alexandra; Kaufman, Darrell S.; Zuschin, Martin</p> <p>2016-04-01</p> <p>Stratigraphic changes in temporal resolution of fossil assemblages and the degree of their stratigraphic mixing in the Holocene deposits are of high importance in paleoecology, conservation paleobiology and <span class="hlt">paleoclimatology</span>. However, few studies quantified downcore changes in time averaging and in stratigraphic disorder on the basis of dating of multiple shells occurring in individual stratigraphic layers. Here, we investigate downcore changes in frequency distribution of postmortem ages of the infaunal bivalve Gouldia minima in two, ~150 cm-thick piston cores (separated by more than 1 km) in the northern Adriatic Sea, close to the Slovenian city Piran at a depth of 24 m. We use radiocarbon-calibrated amino acid racemization to obtain postmortem ages of 564 shells, and quantify age-frequency distributions in 4-5 cm-thick stratigraphic intervals (with 20-30 specimens sampled per interval). Inter-quartile range for individual 4-5 cm-thick layers varies between 850 and 1,700 years, and range encompassing 95% of age data varies between 2,000 and 5,000 years in both cores. The uppermost sediments (20 cm) are age-homogenized and show that median age of shells is ~700-800 years. The interval between 20 and 90 cm shows a gradual increase in median age from ~2,000 to ~5,000 years, with maximum age ranging to ~8,000 years. However, the lowermost parts of both cores show a significant disorder, with median age of 3,100-3,300 years. This temporal disorder implies that many shells were displaced vertically by ~1 m. Absolute and proportional abundance of the bivalve Gouldia minima strongly increases towards the top of the both cores. We hypothesize that such increase in abundance, when coupled with depth-declining reworking, can explain stratigraphic disorder because numerically abundant young shells from the top of the core were more likely buried to larger sediment depths than less frequent shells at intermediate sediment depths.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..1611764S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..1611764S&link_type=ABSTRACT"><span id="translatedtitle">PaleoGeo: a Web based GIS database for paleoenvironmental studies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Song, Wonsuh; Kondo, Yasuhisa; Oguchi, Takashi</p> <p>2014-05-01</p> <p>Paleoenvironmental studies cover various fields such as paleohydrology, geomorphology, paleooceanology, paleobiology, <span class="hlt">paleoclimatology</span>, and chronology. It is difficult for an individual researcher to collect and compile enormous data regarding these fields. We have been compiling portal data and presenting them using a web-based geographical information system (Web-GIS) called PaleoGeo for the multidisciplinary project 'Replacement of Neanderthals by Modern Humans'. The aim of the project is to reconstruct the distribution of Neanderthals and modern humans in time and space in relation to past climate change. We have been collecting information from almost three thousand articles of 13 journals regarding paleoenvironmental research (i.e., Boreas, Catena, Climatic Change, Earth Surface Processes and Landforms, Geomorphology, Journal of Quaternary Science, Palaeogeography, Palaeoclimatology, and Palaeoecology, Quaternary International, Quaternary Research, Quaternary Science Reviews, The Holocene, and The Journal of Geology). The topics of the articles were classified into six themes (paleohydrology, earth surface processes and materials, paleooceanology, paleobiology, palaeoclimatology, and chronology) and 19 subthemes (hydrology, flood, fluvial, glacier, fluvial/glacier, sedimentology, soil, slope process, periglacial, peat land, eolian, sea-level, biology, vegetation, zoology, vegetation/zoology, archaeology, climate, atmosphere, and chronology). The collected data consist of the journal name, information about each paper (authors, title, volume, year, and page numbers), site location (country name, longitude, and latitude), theme, subtheme, keywords, DOI (Digital Object Identifier), and period (era). Location data are indispensable for paleoenvironmental studies. The PaleoGeo shows information with a map, which is an advantage of this database system. However, the number of the paleoenvironmental studies is growing rapidly and we have to effectively cover them as</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009BVol...71.1195V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009BVol...71.1195V"><span id="translatedtitle">Chronostratigraphy of Monte Vulture volcano (southern Italy): secondary mineral microtextures and 39Ar-40Ar systematics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Villa, Igor M.; Buettner, Annett</p> <p>2009-12-01</p> <p>The eruptive history of Monte Vulture has been the subject of several geochronological investigations during the past decades, which reliably dated only a small number of eruptions. Understanding the causes of sub-optimum data yield in the past requires an interdisciplinary approach. We re-analyzed samples from previous works and present new data on samples from the main volcano-stratigraphic units of Monte Vulture, so as to provide an improved, consistent chronostratigraphic database. Imaging of minerals by cathodoluminescence and backscattered electrons reveals that heterochemical, high-temperature deuteric reaction textures are ubiquitous. Such observations are common in metamorphic rocks but had not frequently been reported from volcanic rocks. In view of the mineralogical complexity, we base our chronological interpretation on isochemical steps, defined as steps for which the Cl/K and/or the Ca/K ratios are constant. Isochemical steps carry the isotopic signature of chemically homogeneous mineral phases and therefore allow a well-constrained age interpretation. Comparison of old and new 39Ar-40Ar data proves the reproducibility of age spectra and their shapes. This quantifies the analytical reliability of the irradiation and mass-spectrometric analyses. Anomalous age spectra are a reproducible property of some specific samples and correlate with mineralogical anomalies. The present data allow us to fine-tune the age of the volcanostratigraphic units of Monte Vulture during the known interval of main volcanic activity from ca. 740 to 610 ka. After a very long stasis, the volcanic activity in the Monte Vulture area resumed with diatremic eruptions, one of which (Lago Piccolo di Monticchio, the site of a palynological-<span class="hlt">paleoclimatological</span> drilling) was dated at ca. 140 ka.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFMPP33A1199G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFMPP33A1199G&link_type=ABSTRACT"><span id="translatedtitle">Climate Inferences from Geothermal Measurements in South America</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gurza Fausto, E.; Harris, R. N.; Montenegro, A.; Tassara, A.; Beltrami, H.</p> <p>2014-12-01</p> <p>Analysis of borehole temperature data have contributed significantly to estimating the last millennium surface temperature changes. Additionally, recent analysis have contributed to evaluate the Earth's energy balance by providing a quantitative value for the energy absorbed by the continents in the later part of the 20th century. Knowledge of the surface energy flux is important for understanding the solid Earth - atmosphere boundary condition, land cover changes, and their impact on regional and global climate models. We present data and analysis of 19 borehole temperature versus depth profiles from South America. The dataset includes 10 new borehole logs measured during 2012 at three sites in northern Chile (Vallenar, Sierra Gorda and Sierra Limon Verde). These new measurements complement six temperature logs measured during 1994 in the same region (sites near Michilla and Sierra Limon Verde; Springer et al., Tectonophysics, 1998) and four logs obtained from the NOAA <span class="hlt">Paleoclimatology</span> Borehole Database located in Villa Staff, Toquepala and Talara in Peru. These data were analyzed for climate variability signals of the surface temperature and changes in the Earth's surface energy balance. The analysis suggests a cooling trend during the 19th century of approximately -0.5ºK. Furthermore, results show regionalized temperature changes in ground surface temperatures during the last 50 years with estimates of -0.4ºK in Vallenar, and approximately +1ºK in the Atacama Desert of Northern Chile. We place the results within the context of surface air temperature yearly means obtained from existing meteorological and proxy paleoclimatic data between Peru and Northern Chile. The use of geothermal measurements for climate variability studies provides a further understanding of the climatic and energy cycles of the Southern Hemisphere, where meteorological data can be scarce to non-existent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhRvE..85d6105D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhRvE..85d6105D"><span id="translatedtitle">Analytical framework for recurrence network analysis of time series</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Donges, Jonathan F.; Heitzig, Jobst; Donner, Reik V.; Kurths, Jürgen</p> <p>2012-04-01</p> <p>Recurrence networks are a powerful nonlinear tool for time series analysis of complex dynamical systems. While there are already many successful applications ranging from medicine to <span class="hlt">paleoclimatology</span>, a solid theoretical foundation of the method has still been missing so far. Here, we interpret an ɛ-recurrence network as a discrete subnetwork of a “continuous” graph with uncountably many vertices and edges corresponding to the system's attractor. This step allows us to show that various statistical measures commonly used in complex network analysis can be seen as discrete estimators of newly defined continuous measures of certain complex geometric properties of the attractor on the scale given by ɛ. In particular, we introduce local measures such as the ɛ-clustering coefficient, mesoscopic measures such as ɛ-motif density, path-based measures such as ɛ-betweennesses, and global measures such as ɛ-efficiency. This new analytical basis for the so far heuristically motivated network measures also provides an objective criterion for the choice of ɛ via a percolation threshold, and it shows that estimation can be improved by so-called node splitting invariant versions of the measures. We finally illustrate the framework for a number of archetypical chaotic attractors such as those of the Bernoulli and logistic maps, periodic and two-dimensional quasiperiodic motions, and for hyperballs and hypercubes by deriving analytical expressions for the novel measures and comparing them with data from numerical experiments. More generally, the theoretical framework put forward in this work describes random geometric graphs and other networks with spatial constraints, which appear frequently in disciplines ranging from biology to climate science.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.5572B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.5572B&link_type=ABSTRACT"><span id="translatedtitle">IODP Expedition 359: Maldives Monsoon and Sea Level</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Betzler, Christian; Eberli, Gregor; Zarikian, Carlos</p> <p>2016-04-01</p> <p>Drilling the carbonate platforms and drifts in the Maldives aimed to recover the marine tropical record of the Neogene sea-level changes and the onset of the monsoon related current system in the Indian Ocean. To reach this goal, eight sites were drilled along two transects in the Kardiva Channel in the Inner Sea of the Maldives during IODP Expedition 359. The recovered cores and log data retrieved the material to achieve all the objectives set for the expedition. The most arresting accomplishment is the documentation of how the sea level controlled the carbonate platform system that was thriving during the Miocene Climate Optimum abruptly transitioned into a current-dominated system in the late Middle Miocene. This transition is linked to the onset of an early intensification of the Indian monsoon and the coeval demise of some of the Maldivian platforms. Cores and downhole logs allowed producing a solid record and reconstructing the Neogene environmental changes in the central Indian Ocean. Preliminary shipboard analyses allow a precise dating of this major <span class="hlt">paleoclimatological</span> and paleoceanographical changes, as it also applies for the extension of the Oxygen Minimum Zone (OMZ) into this part of the Indian Ocean. Coring produced a solid framework to foster the post-cruise research of these distinct topics. In addition, complete spliced sections and logging at key sites during Expedition 359 provide the potential to assemble a cycle-based astrochronology for the Neogene section in the Maldives. This high-resolution chronology will allow: 1) independent ages to be assigned to key biostratigraphic events in the Maldives for comparison with those from other tropical regions; 2) more precise ages for the major sequence boundaries and unconformities; and 3) evaluation of higher-resolution sedimentation rate variations.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015CliPD..11.2933A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015CliPD..11.2933A"><span id="translatedtitle">Synchronizing the Greenland ice core and radiocarbon timescales over the Holocene - Bayesian wiggle-matching of cosmogenic radionuclide records</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Adolphi, F.; Muscheler, R.</p> <p>2015-07-01</p> <p>Investigations of past climate dynamics rely on accurate and precise chronologies of the employed climate reconstructions. The radiocarbon dating calibration curve (IntCal13) and the Greenland ice core chronology (GICC05) represent two of the most widely used chronological frameworks in <span class="hlt">paleoclimatology</span> of the past ∼ 50 000 years. However, comparisons of climate records anchored on these chronologies are hampered by the precision and accuracy of both timescales. Here we use common variations in the production rates of 14C and 10Be recorded in tree-rings and ice cores, respectively, to assess the differences between both timescales during the Holocene. We employ a novel statistical approach which leads to strongly reduced and yet, more robust, uncertainty estimates in comparison to earlier work. We demonstrate that the inferred timescale differences are robust independent of (i) the applied ice core 10Be records, (ii) assumptions of the mode of 10Be deposition, as well as (iii) carbon cycle effects on 14C, and in agreement with independent estimates of the timescale differences. Our results imply that the GICC05 counting error is likely underestimated during the most recent 2000 years leading to a dating bias that propagates throughout large parts of the Holocene. Nevertheless, our analysis indicates that the GICC05 counting error is generally a robust uncertainty measurement but care has to be taken when treating it as a nearly Gaussian error distribution. The proposed IntCal13-GICC05 transfer function facilitates the comparison of ice core and radiocarbon dated paleoclimate records at high chronological precision.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6595857','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6595857"><span id="translatedtitle">Reevaluation of California coastal continental borderland evolution: recent evidence from stratigraphic, geophysical, and paleomagnetic studies</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ambos, E.L.; Lund, S.P.; Theyer, F.; Bottjer, D.; Henyey, T.L.</p> <p>1988-03-01</p> <p>Tectonostratigraphic terrane analyses applied during the past decade to California continental borderland evolution distinguished eight or nine terranes that may have docked in the borderland from Cretaceous to mid-Tertiary time. These terranes may in turn be grouped into two composite terranes - the Peninsular Ranges terrane (PRT) and the more northerly Santa Lucia-Orocopia Allochthon (SLOA) - that sutured together during the late Oligocene to mid-Miocene in the southwestern Transverse Ranges. In parallel, the last decade has seen continued refinements in stratigraphy, sea level history, and the accumulation of a large data base of paleomagnetic measurements in southern California. These newly refined data necessitate the reevaluation of the timing sequence of terrane amalgamation in the borderland, and a new scenario for the docking of the PRT against the SLOA can be constructed. Of equal importance in the tectonic reconstruction of the borderland is the consideration of <span class="hlt">paleoclimatological</span> signals, which may mask or conflict with true terrane interactions. For example, a growing body of evidence indicates that prominent reflectors noted in borderland seismic records may correlate with global Neogene paleo-oceanographic events, rather than tectonic events. In addition, recent geophysical investigations of terrane suture zones and the crustal structure beneath terranes in other areas of the western US provide intriguing information on the nature of terrane boundaries. In this context, the PRT-SLOA suture appears as the most fundamental terrane boundary, marked by a zone of high-density, high-velocity material, whereas other terrane boundaries, particularly within the PRT, appear to be of secondary importance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.V23B2806D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.V23B2806D"><span id="translatedtitle">Evaluation of New Geological Reference Materials for U-Series Measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Denton, J. S.; Goldstein, S. J.; Nunn, A. J.; Ui Chearnaigh, K.; Amato, R.; Murrell, M. T.</p> <p>2012-12-01</p> <p>Uranium-series analytical measurements are widely used in geochemistry, geochronology, <span class="hlt">paleoclimatology</span>, volcanology, environmental risk assessment and other fields. Recent advances in high-resolution, rapid, in situ microanalytical techniques e.g. LA-ICP-MS and SIMS present numerous opportunities for the geoanalytical community. As with other analytical techniques, the quality of the elemental concentration and isotopic data obtained through microanalytical techniques is dependent on the accurate characterization of suitable reference materials. Even for the case of fs-laser ablation applications, a range of well-characterized standards are required for high precision U-series work. Advances have been made in evaluating existing standard reference materials for U-series isotopic analysis, but this work is ongoing as more reference materials become available. In this study we present MC-TIMS and MC-ICP-MS results for uranium and thorium isotopic ratios and elemental concentrations measured in a suite of newly available Chinese Geological Standard Glasses (CGSG) designed for microanalysis. These glasses exhibit a range of chemical compositions including basalt, syenite, andesite and a soil. U concentrations for these glasses range from ≈2 to 14 μg/g and [Th]/[U] ratios range from ≈4 to 6. Uranium and thorium concentration and isotopic data will also be presented for rhyolitic obsidian from Macusani, SE Peru, which can be used as a rhyolitic reference material. These high-precision and high-accuracy ratios, from a suite of standards that exhibit a range of natural, non-basaltic compositions, will complement data from existing standards and expand the catalogue of reference materials that are appropriate for in situ U-series work. These results can be used to assess the performance of microanalytical techniques and will facilitate inter-laboratory comparison of data within the broader geoscience community.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMGP12A..07L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMGP12A..07L&link_type=ABSTRACT"><span id="translatedtitle">Dating the Laschamp Excursion: Why Speleothems are Valuable Tools for Constraining the Timing and Duration of Short-Lived Geomagnetic Events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lascu, I.; Feinberg, J. M.; Dorale, J. A.; Cheng, H.; Edwards, R. L.</p> <p>2015-12-01</p> <p>Short-lived geomagnetic events are reflections of geodynamo behavior at small length scales. A rigorous documentation of the anatomy, timing, duration, and frequency of centennial-to-millennial scale geomagnetic events can be invaluable for theoretical and numerical geodynamo models, and for the understanding the finer dynamics of the Earth's core. A critical ingredient for characterizing such geomagnetic instabilities are tightly constrained age models that enable high-resolution magnetostratigraphies. Here we focus on a North American speleothem geomagnetic record of the Laschamp excursion, which was the first geomagnetic excursion recognized and described in the paleomagnetic record, and remains the most studied event of its kind. The geological significance of the Laschamp lies chiefly in the fact that it constitutes a global time-synchronous geochronological marker. The Laschamp excursion occurred around the time of the demise of Homo neanderthalensis, in conjunction with high-amplitude, rapid climatic oscillations leading into the Last Glacial Maximum, and precedes a major supervolcano eruption in the Mediterranean. Thus, the precise determination of the timing and duration of the Laschamp would help in elucidating major scientific questions situated at the intersection of geology, <span class="hlt">paleoclimatology</span>, and anthropology. Here we present a geomagnetic record from a stalagmite collected in Crevice Cave, Missouri, which we have dated using a combination of high-precision 230Th ages and annual layer counting using confocal microscopy. We have found a maximum duration for the Laschamp that spans the interval 42,250-39,700 years BP, and an age of 41,100 ± 350 years BP for the height of the excursion. During this period relative paleointensity decreased by an order of magnitude and the virtual geomagnetic pole was located at southerly latitudes. Our chronology provides the first robust bracketing for the Laschamp excursion, and improves on previous age determinations</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.B13F..05G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.B13F..05G"><span id="translatedtitle">Climatic variations across the Mediterranean Basin reconstructed from pollen and vegetation model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guiot, J.; Leydet, M.; Rotereau, A.</p> <p>2012-12-01</p> <p>The Mediterranean Basin is a complex region with a complex topography at the interface of two climatic systems. Water availability is the main limiting factor of vegetation at low elevation and both temperature and precipitation are equally important at higher elevation. We propose here a gridded reconstruction of the Holocene climate at the scale of the Mediterranean region from pollen by using a vegetation model in inverse mode (Guiot et al, 2009) and so relating vegetation changes to climatic changes in a more mechanistic way than standard statistical approaches. The proxy data used are the pollen series stored in the European Pollen Database (EPD) for the Mediterranean Basin. The period covered is the last 10 ky at a multi-decadal time-step and the climatic variables are winter, summer temperature and precipitation, as well as soil water. BIOME4 model (Kaplan et al, 2003) uses as inputs monthly temperature, precipitation variables and provides outputs comparable to pollen data (assuming that there is a relationship between plant productivity and pollen counts). The idea behind <span class="hlt">paleoclimatological</span> reconstructions is then to obtain inputs, given outputs. This procedure, called model inversion, is achieved with appropriate algorithms in the frame of the Bayesian statistical theory. As CO2 atmospheric concentration is also an input of the model, it is possible to take into account the true variations of the concentration across Holocene to reconstruct the climate. We will present gridded maps of climatic change for typical periods where Mediterranean Basin has known important water stresses. Guiot, J. Et al, 2009. Climate of the Past, 5, 571-583. Kaplan, J., et al, 2003. JGR-Atmos., 108, 8171, doi:10.1029/2002JD002559</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70043329','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70043329"><span id="translatedtitle">Stable isotope deltas: Tiny, yet robust signatures in nature</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brand, Willi A.; Coplen, Tyler B.</p> <p>2012-01-01</p> <p>Although most of them are relatively small, stable isotope deltas of naturally occurring substances are robust and enable workers in anthropology, atmospheric sciences, biology, chemistry, environmental sciences, food and drug authentication, forensic science, geochemistry, geology, oceanography, and <span class="hlt">paleoclimatology</span> to study a variety of topics. Two fundamental processes explain the stable isotope deltas measured in most terrestrial systems: isotopic fractionation and isotope mixing. Isotopic fractionation is the result of equilibrium or kinetic physicochemical processes that fractionate isotopes because of small differences in physical or chemical properties of molecular species having different isotopes. It is shown that the mixing of radioactive and stable isotope end members can be modelled to provide information on many natural processes, including 14C abundances in the modern atmosphere and the stable hydrogen and oxygen isotopic compositions of the oceans during glacial and interglacial times. The calculation of mixing fractions using isotope balance equations with isotope deltas can be substantially in error when substances with high concentrations of heavy isotopes (e.g. 13C, 2H, and 18O ) are mixed. In such cases, calculations using mole fractions are preferred as they produce accurate mixing fractions. Isotope deltas are dimensionless quantities. In the International System of Units (SI), these quantities have the unit 1 and the usual list of prefixes is not applicable. To overcome traditional limitations with expressing orders of magnitude differences in isotope deltas, we propose the term urey (symbol Ur), after Harold C. Urey, for the unit 1. In such a manner, an isotope delta value expressed traditionally as−25 per mil can be written as−25 mUr (or−2.5 cUr or−0.25 dUr; the use of any SI prefix is possible). Likewise, very small isotopic differences often expressed in per meg ‘units’ are easily included (e.g. either+0.015 ‰ or+15 per meg</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012CliPa...8.1637M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012CliPa...8.1637M"><span id="translatedtitle">Effects of dating errors on nonparametric trend analyses of speleothem time series</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mudelsee, M.; Fohlmeister, J.; Scholz, D.</p> <p>2012-10-01</p> <p>A fundamental problem in <span class="hlt">paleoclimatology</span> is to take fully into account the various error sources when examining proxy records with quantitative methods of statistical time series analysis. Records from dated climate archives such as speleothems add extra uncertainty from the age determination to the other sources that consist in measurement and proxy errors. This paper examines three stalagmite time series of oxygen isotopic composition (δ18O) from two caves in western Germany, the series AH-1 from the Atta Cave and the series Bu1 and Bu4 from the Bunker Cave. These records carry regional information about past changes in winter precipitation and temperature. U/Th and radiocarbon dating reveals that they cover the later part of the Holocene, the past 8.6 thousand years (ka). We analyse centennial- to millennial-scale climate trends by means of nonparametric Gasser-Müller kernel regression. Error bands around fitted trend curves are determined by combining (1) block bootstrap resampling to preserve noise properties (shape, autocorrelation) of the δ18O residuals and (2) timescale simulations (models StalAge and iscam). The timescale error influences on centennial- to millennial-scale trend estimation are not excessively large. We find a "mid-Holocene climate double-swing", from warm to cold to warm winter conditions (6.5 ka to 6.0 ka to 5.1 ka), with warm-cold amplitudes of around 0.5‰ δ18O; this finding is documented by all three records with high confidence. We also quantify the Medieval Warm Period (MWP), the Little Ice Age (LIA) and the current warmth. Our analyses cannot unequivocally support the conclusion that current regional winter climate is warmer than that during the MWP.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012CliPD...8.1973M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012CliPD...8.1973M"><span id="translatedtitle">Effects of dating errors on nonparametric trend analyses of speleothem time series</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mudelsee, M.; Fohlmeister, J.; Scholz, D.</p> <p>2012-05-01</p> <p>A fundamental problem in <span class="hlt">paleoclimatology</span> is to take fully into account the various error sources when examining proxy records with quantitative methods of statistical time series analysis. Records from dated climate archives such as speleothems add extra uncertainty from the age determination to the other sources that consist in measurement and proxy errors. This paper examines three stalagmite time series of oxygen isotopic composition (δ18O) from two caves in Western Germany, the series AH-1 from the Atta cave and the series Bu1 and Bu4 from the Bunker cave. These records carry regional information about past changes in winter precipitation and temperature. U/Th and radiocarbon dating reveals that they cover the later part of the Holocene, the past 8.6 thousand years (ka). We analyse centennial- to millennial-scale climate trends by means of nonparametric Gasser-Müller kernel regression. Error bands around fitted trend curves are determined by combining (1) block bootstrap resampling to preserve noise properties (shape, autocorrelation) of the δ18O residuals and (2) timescale simulations (models StalAge and iscam). The timescale error influences on centennial- to millennial-scale trend estimation are not excessively large. We find a "mid-Holocene climate double-swing", from warm to cold to warm winter conditions (6.5 ka to 6.0 ka to 5.1 ka), with warm-cold amplitudes of around 0.5‰ δ18O; this finding is documented by all three records with high confidence. We also quantify the Medieval Warm Period (MWP), the Little Ice Age (LIA) and the current warmth. Our analyses cannot unequivocally support the conclusion that current regional winter climate is warmer than that during the MWP.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014CliPa..10.2007W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014CliPa..10.2007W"><span id="translatedtitle">The global monsoon across timescales: coherent variability of regional monsoons</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, P. X.; Wang, B.; Cheng, H.; Fasullo, J.; Guo, Z. T.; Kiefer, T.; Liu, Z. Y.</p> <p>2014-11-01</p> <p>Monsoon has earned increasing attention from the climate community since the last century, yet only recently have regional monsoons been recognized as a global system. It remains a debated issue, however, as to what extent and at which timescales the global monsoon can be viewed as a major mode of climate variability. For this purpose, a PAGES (Past Global Changes) working group (WG) was set up to investigate the concept of the global monsoon and its future research directions. The WG's synthesis is presented here. On the basis of observation and proxy data, the WG found that the regional monsoons can vary coherently, although not perfectly, at various timescales, varying between interannual, interdecadal, centennial, millennial, orbital and tectonic timescales, conforming to the global monsoon concept across timescales. Within the global monsoon system, each subsystem has its own features, depending on its geographic and topographic conditions. Discrimination between global and regional components in the monsoon system is a key to revealing the driving factors in monsoon variations; hence, the global monsoon concept helps to enhance our understanding and to improve future projections of the regional monsoons. This paper starts with a historical review of the global monsoon concept in both modern and <span class="hlt">paleo-climatology</span>, and an assessment of monsoon proxies used in regional and global scales. The main body of the paper is devoted to a summary of observation data at various timescales, providing evidence of the coherent global monsoon system. The paper concludes with a projection of future monsoon shifts in a warming world. The synthesis will be followed by a companion paper addressing driving mechanisms and outstanding issues in global monsoon studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014CliPD..10.2163W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014CliPD..10.2163W"><span id="translatedtitle">The Global Monsoon across Time Scales: is there coherent variability of regional monsoons?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, P. X.; Wang, B.; Cheng, H.; Fasullo, J.; Guo, Z. T.; Kiefer, T.; Liu, Z. Y.</p> <p>2014-05-01</p> <p>Monsoon has earned increasing attention from the climate community since the last century, yet only recently regional monsoons have been recognized as a global system. It remains a debated issue, however, as to what extent and at which time scales the global monsoon can be viewed as a major mode of climate variability. For this purpose a PAGES Working Group (WG) was set up to investigate the concept of the global monsoon and its future research directions. The WG's synthesis is presented here. On the basis of observation and proxy data, the WG found that the regional monsoons can vary coherently, although not perfectly, at various time scales, ranging from interannual, interdecadal, centennial and millennial, up to orbital and tectonics time scales, conforming the global monsoon concept across time scales. Within the global monsoon system each subsystem has its own features depending on its geographic and topographic conditions. Discrimination of global and regional components in the monsoon system is a key to reveal the driving factors of monsoon variations, hence the global monsoon concept helps to enhance our understanding and to improve future projection of the regional monsoons. This paper starts with a historical review of the global monsoon concept in both modern and <span class="hlt">paleo-climatology</span>, and an assessment of monsoon proxies used in regional and global scales. The main body of the paper is devoted to a summary of observation data at various time scales, providing evidence for the coherent global monsoon system. The paper concludes with a projection of future monsoon shifts into a warming world. The synthesis will be followed by a companying paper to discuss driving mechanisms and outstanding issues in the global monsoon studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70035439','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70035439"><span id="translatedtitle">An integrated chronostratigraphic data system for the twenty-first century</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sikora, P.J.; Ogg, J.G.; Gary, A.; Cervato, C.; Gradstein, F.; Huber, B.T.; Marshall, C.; Stein, J.A.; Wardlaw, B.</p> <p>2006-01-01</p> <p>Research in stratigraphy is increasingly multidisciplinary and conducted by diverse research teams whose members can be widely separated. This developing distributed-research process, facilitated by the availability of the Internet, promises tremendous future benefits to researchers. However, its full potential is hindered by the absence of a development strategy for the necessary infrastructure. At a National Science Foundation workshop convened in November 2001, thirty quantitative stratigraphers and database specialists from both academia and industry met to discuss how best to integrate their respective chronostratigraphic databases. The main goal was to develop a strategy that would allow efficient distribution and integration of existing data relevant to the study of geologic time. Discussions concentrated on three major themes: database standards and compatibility, strategies and tools for information retrieval and analysis of all types of global and regional stratigraphic data, and future directions for database integration and centralization of currently distributed depositories. The result was a recommendation to establish an integrated chronostratigraphic database, to be called Chronos, which would facilitate greater efficiency in stratigraphic studies (http://www.chronos.org/) . The Chronos system will both provide greater ease of data gathering and allow for multidisciplinary synergies, functions of fundamental importance in a variety of research, including time scale construction, paleoenvironmental analysis, <span class="hlt">paleoclimatology</span> and paleoceanography. Beyond scientific research, Chronos will also provide educational and societal benefits by providing an accessible source of information of general interest (e.g., mass extinctions) and concern (e.g., climatic change). The National Science Foundation has currently funded a three-year program for implementing Chronos.. ?? 2006 Geological Society of America. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10115504','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10115504"><span id="translatedtitle">Climate research in the former Soviet Union. FASAC: Foreign Applied Sciences Assessment Center technical assessment report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ellingson, R.G.; Baer, F.; Ellsaesser, H.W.; Harshvardhan; Hoffert, M.I.; Randall, D.A.</p> <p>1993-09-01</p> <p>This report assesses the state of the art in several areas of climate research in the former Soviet Union. This assessment was performed by a group of six internationally recognized US experts in related fields. The areas chosen for review are: large-scale circulation processes in the atmosphere and oceans; atmospheric radiative processes; cloud formation processes; climate effects of natural atmospheric disturbances; and the carbon cycle, paleoclimates, and general circulation model validation. The study found an active research community in each of the above areas. Overall, the quality of climate research in the former Soviet Union is mixed, although the best Soviet work is as good as the best corresponding work in the West. The best Soviet efforts have principally been in theoretical studies or data analysis. However, an apparent lack of access to modern computing facilities has severely hampered the Soviet research. Most of the issues considered in the Soviet literature are known, and have been discussed in the Western literature, although some extraordinary research in <span class="hlt">paleoclimatology</span> was noted. Little unusual and exceptionally creative material was found in the other areas during the study period (1985 through 1992). Scientists in the former Soviet Union have closely followed the Western literature and technology. Given their strengths in theoretical and analytical methods, as well as their possession of simplified versions of detailed computer models being used in the West, researchers in the former Soviet Union have the potential to make significant contributions if supercomputers, workstations, and software become available. However, given the current state of the economy in the former Soviet Union, it is not clear that the computer gap will be bridged in the foreseeable future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012QSRv...31...17O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012QSRv...31...17O"><span id="translatedtitle">Review of probabilistic pollen-climate transfer methods</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ohlwein, Christian; Wahl, Eugene R.</p> <p>2012-01-01</p> <p>Pollen-climate transfer methods are reviewed from a Bayesian perspective and with a special focus on the formulation of uncertainties. This approach is motivated by recent developments of spatial multi-proxy Bayesian hierarchical models (BHM), which allow synthesizing local reconstructions from different proxies for a spatially complete picture of past climate. In order to enhance the pollen realism in these models we try to bridge the gap between spatial statistics and <span class="hlt">paleoclimatology</span> and show how far classical pollen-climate transfer concepts such as regression methods, mutual climatic range, modern analogues, plant functional types, and biomes can be understood in novel ways by refining the data models used in BHMs. As a case study, we discuss modeling of uncertainty by introducing a new probabilistic pollen ratio model, which is a simplified variation of the modern analogue technique (MAT) including the concept of response surfaces and designed for later inclusion in a spatial multiproxy BHM. Applications to fossil pollen data from varved sediments in three nearby lakes in west-central Wisconsin, USA and for a Holocene fossil pollen record from southern California, USA provide local climate reconstructions of summer temperature for the past millennium and the Holocene respectively. The performance of the probabilistic model is generally similar in comparison to MAT-derived reconstructions using the same data. Furthermore, the combination of co-location and precise dating for the three fossil sites in Wisconsin allows us to study the issue of site-specific uncertainty and to test the assumption of ergodicity in a real-world example. A multivariate ensemble kernel dressing approach derived from the post-processing of climate simulations reveals that the overall interpretation based on the individual reconstructions remains essentially unchanged, but the single-site reconstructions underestimate the overall uncertainty.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003PalOc..18.1065P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003PalOc..18.1065P"><span id="translatedtitle">Glacial North Atlantic: Sea-surface conditions reconstructed by GLAMAP 2000</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pflaumann, U.; Sarnthein, M.; Chapman, M.; D'Abreu, L.; Funnell, B.; Huels, M.; Kiefer, T.; Maslin, M.; Schulz, H.; Swallow, J.; van Kreveld, S.; Vautravers, M.; Vogelsang, E.; Weinelt, M.</p> <p>2003-09-01</p> <p>The response of the tropical ocean to global climate change and the extent of sea ice in the glacial nordic seas belong to the great controversies in <span class="hlt">paleoclimatology</span>. Our new reconstruction of peak glacial sea surface temperatures (SSTs) in the Atlantic is based on census counts of planktic foraminifera, using the Maximum Similarity Technique Version 28 (SIMMAX-28) modern analog technique with 947 modern analog samples and 119 well-dated sediment cores. Our study compares two slightly different scenarios of the Last Glacial Maximum (LGM), the Environmental Processes of the Ice Age: Land, Oceans, Glaciers (EPILOG), and Glacial Atlantic Ocean Mapping (GLAMAP 2000) time slices. The comparison shows that the maximum LGM cooling in the Southern Hemisphere slightly preceeded that in the north. In both time slices sea ice was restricted to the north western margin of the nordic seas during glacial northern summer, while the central and eastern parts were ice-free. During northern glacial winter, sea ice advanced to the south of Iceland and Faeroe. In the central northern North Atlantic an anticyclonic gyre formed between 45° and 60°N, with a cool water mass centered west of Ireland, where glacial cooling reached a maximum of >12°C. In the subtropical ocean gyres the new reconstruction supports the glacial-to-interglacial stability of SST as shown by () [1981]. The zonal belt of minimum SST seasonality between 2° and 6°N suggests that the LGM caloric equator occupied the same latitude as today. In contrast to the CLIMAP reconstruction, the glacial cooling of the tropical east Atlantic upwelling belt reached up to 6°-8°C during Northern Hemisphere summer. Differences between these SIMMAX-based and published U37k- and Mg/Ca-based equatorial SST records are ascribed to strong SST seasonalities and SST signals that were produced by different planktic species groups during different seasons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000JGR...10520055P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000JGR...10520055P"><span id="translatedtitle">Interannual Atmosphere-Biosphere Variation: Implications for observation and modeling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prince, S. D.; Goward, S. N.; Goetz, S.; Czajkowski, K.</p> <p>2000-08-01</p> <p>Climate-land surface interactions have been mainly investigated either in terms of short-term modification of fluxes of matter, momentum, and energy, which primarily affect the atmosphere, or in the long-term, biogeographical impacts of climatic conditions on the type of vegetation that occupies a site. Logically, there must be time and space scales at which these short-term and biogeographical climate-land surface interactions are both relevant. It is proposed that it is these intermediate scales, at which physiological and biogeographical processes cannot easily be separated, which are most relevant in the study of climate change, and that new analytical and modeling approaches are needed which include both. Moreover, periods of rapid climate change and periods of increasing anthropogenic impacts on the land surface can be expected to induce a wide range of transient vegetation dynamics. The timescale of interest here excludes equilibria and demands a consideration of the outcomes of processes that have a wide variety of temporal frequencies. A recent workshop brought together ecologists and climatologists with interests in observing, modeling, and predicting the dynamics of land-atmosphere processes at the inteannual to decadal timescale. The result was a proposal to exploit recently developed archives of remotely sensed data and others such as paleobotanical and <span class="hlt">paleoclimatological</span> records in order to advance beyond the polarized concept of land-atmosphere processes which comes from a consideration only of short and long time periods, while ignoring their interactions. The new demands of this agenda for observational and analytical methods are considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.9505L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.9505L&link_type=ABSTRACT"><span id="translatedtitle">Drought as a Catalyst for Early Medieval European Subsistence Crises and Violence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ludlow, Francis; Cook, Edward; Kostick, Conor; McCormick, Michael</p> <p>2016-04-01</p> <p>Tree-ring records provide one of most reliable means of reconstructing past climatic conditions, from longer-term multi-decadal fluctuations in temperature and precipitation to inter-annual variability, including years that experienced extreme weather. When combined with written records of past societal behaviour and the incidence of major societal stresses (e.g., famine, disease, and conflict), such records hold the potential to shed new light on historical interactions between climate and society. Recent years have seen the continued development of long dendroclimatic reconstructions, including, most recently the development of the Old World Drought Atlas (OWDA; Cook et al., 2015) which for the first time makes available a robust reconstruction of spring-summer hydroclimatic conditions and extremes for the greater European region, including the entirety of the Dark Ages. In this paper, we examine the association between hydroclimatic extremes identified in the OWDA and well-dated reports of severe drought in early medieval European annals and chronicles, and find a clear statistical correspondence, further confirming the accuracy of the OWDA and its importance as an independent record of hydroclimatic extremes, a resource that can now be drawn upon in both <span class="hlt">paleoclimatology</span> and studies of climatic impacts on human society. We proceed to examine the association between hydroclimatic extremes identified in the OWDA and the incidence of a range of major societal stresses (scarcity and famine, epidemic disease, and mass human mortality) drawn from an exhaustive survey of early medieval European annals and chronicles. The outcome of this comparison firmly implicates drought as a significant driver of major societal stresses during early medieval times. Using a record of the violent killings of societal elites recorded on a continuous annual basis in medieval Irish monastic annals, we further examine the role of hydroclimatic extremes as triggers in medieval violence</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMPP11B2022H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMPP11B2022H"><span id="translatedtitle">Paleocene climate change in the San Juan Basin, New Mexico: A paleosol perspective</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hobbs, K.; Fawcett, P. J.</p> <p>2012-12-01</p> <p>The fluvial Nacimiento Formation in the San Juan Basin, New Mexico, is host to abundant paleosols of early Paleocene age (Danian stage, Puercan/Torrejonian NALMA). Paleosols with vertic properties are common, with less common horizonated clay-rich paleosols and siliceous sandy paleosols. Since paleosols represent under the long-term average state of climate conditions over 102-105 years of pedogenesis, San Juan Basin paleosols are among the most useful proxies for understanding the history of local and regional climate conditions and change in the Paleocene. Here we present geochemical and <span class="hlt">paleoclimatological</span> interpretations of paleosols from the Nacimiento Formation in the western and southern San Juan Basin; discuss their significance on interpretation of basin sedimentology; and seek possible modern analogues. An interesting and seemingly paradoxical problem in the Paleocene San Juan Basin is the presence of vertic paleosols (typically associated with subhumid to semiarid climates) in close geographic and stratigraphic proximity to well-horizonated or base-poor paleosols and Arecales and Crocodilia fossils (all associated with tropical to subtropical humid climates). Preliminary data show that some San Juan Basin vertic paleosols formed under mean annual temperatures (MAT) of ~12° ± 4.4° C and mean annual precipitation (MAP) amounts of ~1,100 mm. The mineral composition and presence of kaolinite in more horizonated paleosols suggest they formed under warmer and wetter conditions. This study also investigates the silcrete-bearing paleosols of the Nacimiento Formation. Pedogenic silcretes typically form in stable landscapes with subtropical to tropical variable moisture climates. Unlike other Laramide basins where Paleogene hyperthermals often are represented by reddened paleosols, it is possible that hyperthermals are represented by silcretes in the San Juan Basin. Regardless of the pedogenic representation of hyperthermals in the San Juan Basin, the paleosols</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.8413S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.8413S"><span id="translatedtitle">Ontology Design Patterns: Bridging the Gap Between Local Semantic Use Cases and Large-Scale, Long-Term Data Integration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shepherd, Adam; Arko, Robert; Krisnadhi, Adila; Hitzler, Pascal; Janowicz, Krzysztof; Chandler, Cyndy; Narock, Tom; Cheatham, Michelle; Schildhauer, Mark; Jones, Matt; Raymond, Lisa; Mickle, Audrey; Finin, Tim; Fils, Doug; Carbotte, Suzanne; Lehnert, Kerstin</p> <p>2015-04-01</p> <p>Integrating datasets for new use cases is one of the common drivers for adopting semantic web technologies. Even though linked data principles enables this type of activity over time, the task of reconciling new ontological commitments for newer use cases can be daunting. This situation was faced by the Biological and Chemical Oceanography Data Management Office (BCO-DMO) as it sought to integrate its existing linked data with other data repositories to address newer scientific use cases as a partner in the GeoLink Project. To achieve a successful integration with other GeoLink partners, BCO-DMO's metadata would need to be described using the new ontologies developed by the GeoLink partners - a situation that could impact semantic inferencing, pre-existing software and external users of BCO-DMO's linked data. This presentation describes the process of how GeoLink is bridging the gap between local, pre-existing ontologies to achieve scientific metadata integration for all its partners through the use of ontology design patterns. GeoLink, an NSF EarthCube Building Block, brings together experts from the geosciences, computer science, and library science in an effort to improve discovery and reuse of data and knowledge. Its participating repositories include content from field expeditions, laboratory analyses, journal publications, conference presentations, theses/reports, and funding awards that span scientific studies from marine geology to marine ecology and biogeochemistry to <span class="hlt">paleoclimatology</span>. GeoLink's outcomes include a set of reusable ontology design patterns (ODPs) that describe core geoscience concepts, a network of Linked Data published by participating repositories using those ODPs, and tools to facilitate discovery of related content in multiple repositories.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22462621','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22462621"><span id="translatedtitle">Stable isotope deltas: tiny, yet robust signatures in nature.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Brand, Willi A; Coplen, Tyler B</p> <p>2012-09-01</p> <p>Although most of them are relatively small, stable isotope deltas of naturally occurring substances are robust and enable workers in anthropology, atmospheric sciences, biology, chemistry, environmental sciences, food and drug authentication, forensic science, geochemistry, geology, oceanography, and <span class="hlt">paleoclimatology</span> to study a variety of topics. Two fundamental processes explain the stable isotope deltas measured in most terrestrial systems: isotopic fractionation and isotope mixing. Isotopic fractionation is the result of equilibrium or kinetic physicochemical processes that fractionate isotopes because of small differences in physical or chemical properties of molecular species having different isotopes. It is shown that the mixing of radioactive and stable isotope end members can be modelled to provide information on many natural processes, including (14)C abundances in the modern atmosphere and the stable hydrogen and oxygen isotopic compositions of the oceans during glacial and interglacial times. The calculation of mixing fractions using isotope balance equations with isotope deltas can be substantially in error when substances with high concentrations of heavy isotopes (e.g. (13)C, (2)H, and (18)O ) are mixed. In such cases, calculations using mole fractions are preferred as they produce accurate mixing fractions. Isotope deltas are dimensionless quantities. In the International System of Units (SI), these quantities have the unit 1 and the usual list of prefixes is not applicable. To overcome traditional limitations with expressing orders of magnitude differences in isotope deltas, we propose the term urey (symbol Ur), after Harold C. Urey, for the unit 1. In such a manner, an isotope delta value expressed traditionally as-25 per mil can be written as-25 mUr (or-2.5 cUr or-0.25 dUr; the use of any SI prefix is possible). Likewise, very small isotopic differences often expressed in per meg 'units' are easily included (e.g. either+0.015 ‰ or+15 per meg</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011SciDr..12...32Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011SciDr..12...32Y"><span id="translatedtitle">IODP Expedition 325: Great Barrier Reefs Reveals Past Sea-Level, Climate and Environmental Changes Since the Last Ice Age</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yokoyama, Y.; Webster, J. M.; Cotterill, C.; Braga, J. C.; Jovane, L.; Mills, H.; Morgan, S.; Suzuki, A.; IODP Expedition 325 Scientists, the</p> <p>2011-09-01</p> <p>The timing and courses of deglaciations are key components in understanding the global climate system. Cyclic changes in global climate have occurred, with growth and decay of high latitude ice sheets, for the last two million years. It is believed that these fluctuations are mainly controlled by periodic changes to incoming solar radiation due to the changes in Earth's orbit around the sun. However, not all climate variations can be explained by this process, and there is the growing awareness of the important role of internal climate feedback mechanisms. Understanding the nature of these feedbacks with regard to the timing of abrupt global sea-level and climate changes is of prime importance. The tropical ocean is one of the major components of the feedback system, and hence reconstructions of temporal variations in sea-surface conditions will greatly improve our understanding of the climate system. The Integrated Ocean Drilling Program (IODP) Expedition 325 drilled 34 holes across 17 sites in the Great Barrier Reef, Australia to recover fossil coral reef deposits. The main aim of the expedition was to understand the environmental changes that occurred during the last ice age and subsequent deglaciation, and more specifically (1) establish the course of sea-level change, (2) reconstruct the oceanographic conditions, and (3) determine the response of the reef to these changes. We recovered coral reef deposits from water depths down to 126 m that ranged in age from 9,000 years to older than 30,000 years ago. Given that the interval of the dated materials covers several <span class="hlt">paleoclimatologically</span> important events, including the Last Glacial Maximum, we expect that ongoing scientific analyses will fulfill the objectives of the expedition. doi:<a href="http://dx.doi.org/10.2204/iodp.sd.12.04.2011" target="_blank">10.2204/iodp.sd.12.04.2011</a></p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMPP32B0527V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMPP32B0527V"><span id="translatedtitle">Ecology of the Ostracode Loxoconcha in Chesapeake Bay: Application to Shell Chemistry Calibration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vann, C. D.; Cronin, T. M.; Dwyer, G. S.</p> <p>2001-12-01</p> <p>The successful application of magnesium/calcium ratios (Mg/Ca) of ostracode shells to paleothermometry depends on understanding both the factors controlling the uptake of Mg into the ostracode calcitic shell and the species' seasonal ecology, which determines the time of year when adult molting occurs. Loxoconcha, a cosmopolitan shallow-water ostracode genus that evolved in the Paleogene, includes more than 500 extant species, many inhabiting temperate regions, making it a potentially valuable tool in Cenozoic paleothermometry. We studied the population ecology of Loxoconcha matagordensis, an epiphytal species common in bays and estuaries along the Atlantic and Gulf Coasts of North America, for application to Holocene <span class="hlt">paleoclimatology</span> in temperate coastal regions. L. matagordensis populations collected from Zostera marina beds in Chesapeake Bay (N 37° 47'4.3", W 76° 17'44.4"; N 37° 47'4.5", W 76° 17'31.0") show that its population dynamics and Zostera height appear to be regulated primarily by seasonal oscillations in water temperature. As water temperature increased from 14.8° to 24.6° C between April and July 2001, a spring breeding season occurred shifting the age structure of the Loxoconcha population from an entirely adult population (individuals that wintered over) to a predominately juvenile population comprised of all eight growth (molt) stages. Most new adults secreted their shells during May and June, although in some years, a second breeding season may occur in late August/September. Other temperate species of this genus also appear to have spring/early summer adult shell growth. Our results suggest that the Mg/Ca ratios from Holocene adult shells of Loxoconcha obtained from sediment cores provide a record of late spring/early summer water temperature variability linked to decadal and centennial climate processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMPP31B1860F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMPP31B1860F"><span id="translatedtitle">Do Speleothem Stable Isotope Records Contain Hidden Tropical Cyclone Histories? Exploring C-O Isotope Correlation Patterns for Indicators of Tropical Cyclone Masking</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frappier, A. E.; Rossington, C.</p> <p>2013-12-01</p> <p>The newly-described tropical cyclone masking effect on stable isotope paleohydrological signals in speleothem records arises from the intermittent delivery of large pulses of isotopically distinct tropical cyclone rain. Recent work shows that 18-O depleted tropical cyclone stormwater depresses the δ18O value of speleothem calcite for months to years following a tropical cyclone event, masking the background stable isotope signal of persistent climate variability. Periods of high local storm activity can lead to speleothem calcite paleohydrological signals with significant wet biases on interannual to decadal timescales. Because speleothem carbon isotope ratios are independent of tropical cyclone rainfall, tropical speleothems are known to exhibit moderate C-O isotope covariation over time, periods when C-O isotope covariation breaks down and δ18O values are low may provide a marker for times when tropical cyclone masking is important. If so, existing speleothem stable isotope records from tropical cyclone-prone regions may contain signatures of tropical cyclone masking in the temporal evolution of C-O isotope covariation patterns. We present results from an exploratory analysis of several published speleothem records that are candidates for containing tropical cyclone masking signals. For each speleothem, overall C-O isotope covariation coefficients were calculated, and transient covariation patterns were analyzed using a sliding correlation index, the Covariation of Stable Isotopes (CoSI) index, and Local Correlation (LoCo). Local tropical cyclone historical and paleotempest records are compared and a method is presented to test for the presence of tropical cyclone masking intervals. The implications for speleothem <span class="hlt">paleoclimatology</span> and paleotempestology are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CliPa..12...15A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CliPa..12...15A"><span id="translatedtitle">Synchronizing the Greenland ice core and radiocarbon timescales over the Holocene - Bayesian wiggle-matching of cosmogenic radionuclide records</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Adolphi, F.; Muscheler, R.</p> <p>2016-01-01</p> <p>Investigations of past climate dynamics rely on accurate and precise chronologies of the employed climate reconstructions. The radiocarbon dating calibration curve (IntCal13) and the Greenland ice core chronology (GICC05) represent two of the most widely used chronological frameworks in <span class="hlt">paleoclimatology</span> of the past ˜ 50 000 years. However, comparisons of climate records anchored on these chronologies are hampered by the precision and accuracy of both timescales. Here we use common variations in the production rates of 14C and 10Be recorded in tree-rings and ice cores, respectively, to assess the differences between both timescales during the Holocene. Compared to earlier work, we employ a novel statistical approach which leads to strongly reduced and yet, more robust, uncertainty estimates. Furthermore, we demonstrate that the inferred timescale differences are robust independent of (i) the applied ice core 10Be records, (ii) assumptions of the mode of 10Be deposition, as well as (iii) carbon cycle effects on 14C, and (iv) in agreement with independent estimates of the timescale differences. Our results imply that the GICC05 counting error is likely underestimated during the most recent 2000 years leading to a dating bias that propagates throughout large parts of the Holocene. Nevertheless, our analysis indicates that the GICC05 counting error is generally a robust uncertainty measurement but care has to be taken when treating it as a nearly Gaussian error distribution. The proposed IntCal13-GICC05 transfer function facilitates the comparison of ice core and radiocarbon dated paleoclimate records at high chronological precision.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..1111983T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..1111983T"><span id="translatedtitle">Stable isotope variability in snow on an alpine glacier in Switzerland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Town, M. S.; Walden, V. P.; Huwald, H.; Higgins, C. W.; Nadeau, D.; Simoni, S.; Parlange, M. B.</p> <p>2009-04-01</p> <p>Understanding the variability and post-depositional modification of water stable isotopes in snow is of significant importance to <span class="hlt">paleoclimatology</span> and alpine hydrology. There is modeling evidence that the stable isotopic content of near-surface snow may change as a result of deposition of atmospheric water vapor within the snow. These findings have yet to be confirmed by observation. In addition, ground water and river sources are often identified by their isotopic signature. Understanding the source of the isotopic signature, the recently fallen snow, and how that signature changes just after deposition may aid alpine watershed assessments. Here we present meteorological, hydrologic, and isotopic data taken from Feb-Mar 2008 on a high altitude alpine glacier, the Plaine Morte, in Switzerland. The Plaine Morte is large plateau (8 km2), surrounded by a 300 m ridge line. We use this site (2775 m a.s.l., 46.3oN, 7.5oE) as a laboratory for understanding the effect of meteorology on the isotopic signature of the near-surface snow. The snow surface of the Plaine Morte is isotopically uniform, except in areas that collect large amounts of drift from neighboring ridges and slopes. We present ^18O profiles down to 1.2 m for five different days. While the spatial variability of ^18O of the surface snow is less than 1 per mil, the variability of the profiles is on the order of 15-20 per mil. We investigate the relationship between the ^18O profiles and the available meteorological data to look for evidence of post-depositional modification due to the influence of the atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMPP31B2255T&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMPP31B2255T&link_type=ABSTRACT"><span id="translatedtitle">Evidence for Global Biogeochemical Changes During the Toarcian Oceanic Anoxic Event</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Them, T. R., II; Gill, B. C.; Gröcke, D. R.; Selby, D. S.; Martindale, R. C.; Caruthers, A. H.; Tulsky, E. T. T.</p> <p>2015-12-01</p> <p>The global versus regional nature of the Toarcian Oceanic Anoxic Event (T-OAE; ~183 million years ago) has been heavily debated over the course of the last decade. Several lines of geochemical evidence support a significant perturbation to the carbon cycle and redox-sensitive elemental cycles across this interval. It is thought that these represent feedbacks to the emplacement of the Karoo-Ferrar large igneous province. These include: elevated atmospheric pCO2, an enhanced greenhouse effect and hydrologic cycle leading to increased weathering rates, dissociation of biogenic methane clathrates, and widespread ocean anoxia. Despite evidence for these global phenomena, the overwhelming majority of stratigraphic successions studied are located in Europe. The global magnitude of these biogeochemical perturbations has been challenged, with some considering that this event was regional to Europe, and others suggesting that the carbon isotope excursion (CIE) itself is not a reliable stratigraphic marker. In order to test these competing hypotheses, we have generated a geochemical dataset to reconstruct paleoceanographic and <span class="hlt">paleoclimatological</span> changes across the T-OAE from western North America. The Toarcian strata in western Alberta consist primarily of organic-rich calcareous siltstones and shales. These deposits represent ideal sedimentary facies to reconstruct environmental changes through the use of geochemical proxy data, especially those that use redox-sensitive transition metals. Ammonite biostratigraphy suggests a nearly continuous sequence from the late Pliensbachian to middle Toarcian. The organic carbon isotopes show the prominent negative CIE interpreted to relate to the release of isotopically depleted carbon at the onset of the T-OAE. Pyrite sulfur weight percentages increase across the CIE and remain elevated, and iron speciation data suggest the development of anoxic conditions. Initial osmium isotope compositions become more radiogenic during the CIE</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMPP13A2265L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMPP13A2265L"><span id="translatedtitle">Geochemical Approach to Archaeal Ecology: δ13C of GDGTs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lichtin, S.; Warren, C.; Pearson, A.; Pagani, M.</p> <p>2015-12-01</p> <p>Over the last decade and a half, glycerol dialkyl glycerol tetraethers (GDGTs) have increasingly been used to reconstruct environmental temperatures; proxies like TEX86 that correlate the relative abundance of these archaeal cell membrane lipids to sea surface temperature are omnipresent in <span class="hlt">paleoclimatology</span> literature. While it has become common to make claims about past temperatures using GDGTs, our present understanding of the organisms that synthesize the compounds is still quite limited. The generally accepted theory states that microorganisms like the Thaumarchaeota modify the structure of membrane lipids to increase intermolecular interactions, strengthening the membrane at higher temperatures. Yet to date, culture experiments have been largely restricted to a single species, Nitrosopumilus maritimes, and recent studies on oceanic archaeal rRNA have revealed that these biomarkers are produced in diverse, heterogeneous, and site-specific communities. This brings up questions as to whether different subclasses of GDGTs, and all subsequent proxies, represent adaptation within a single organismal group or a shift in community composition. To investigate whether GDGTs with different chain structures, from the simple isoprenoidal GDGT-0 to Crenarchaeol with its many cyclopentane groups, are sourced from archaea with similar or disparate metabolic pathways—and if that information is inherited in GDGTs trapped in marine sediments—this study examines the stable carbon isotope values (δ13C) of GDGTs extracted from the uppermost meters of sediment in the Orca Basin, Gulf of Mexico, using spooling-wire microcombustion isotope-ratio mass spectrometer (SWiM-IRMS), tackling a fundamental assumption of the TEX86 proxy that influences the way we perceive the veracity of existing temperature records.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.C43C0813C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.C43C0813C"><span id="translatedtitle">Application of Laser Induced Breakdown Spectroscopy under Polar Conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Clausen, J. L.; Hark, R.; Bol'shakov, A.; Plumer, J.</p> <p>2015-12-01</p> <p>Over the past decade our research team has evaluated the use of commercial-off-the-shelf laser-induced breakdown spectroscopy (LIBS) for chemical analysis of snow and ice samples under polar conditions. One avenue of research explored LIBS suitability as a detector of paleo-climate proxy indicators (Ca, K, Mg, and Na) in ice as it relates to atmospheric circulation. LIBS results revealed detection of peaks for C and N, consistent with the presence of organic material, as well as major ions (Ca, K, Mg, and Na) and trace metals (Al, Cu, Fe, Mn, Ti). The detection of Ca, K, Mg, and Na confirmed that LIBS has sufficient sensitivity to be used as a tool for characterization of paleo-climate proxy indicators in ice-core samples. Techniques were developed for direct analysis of ice as well as indirect measurements of ice via melting and filtering. Pitfalls and issues of direct ice analysis using several cooling techniques to maintain ice integrity will be discussed. In addition, a new technique, laser ablation molecular isotopic spectroscopy (LAMIS) was applied to detection of hydrogen and oxygen isotopes in ice as isotopic analysis of ice is the main tool in <span class="hlt">paleoclimatology</span> and glaciology studies. Our results demonstrated that spectra of hydroxyl isotopologues 16OH, 18OH, and 16OD can be recorded with a compact spectrograph to determine hydrogen and oxygen isotopes simultaneously. Quantitative isotopic calibration for ice analysis can be accomplished using multivariate chemometric regression as previously realized for water vapor. Analysis with LIBS and LAMIS required no special sample preparation and was about ten times faster than analysis using ICP-MS. Combination of the two techniques in one portable instrument for in-field analysis appears possible and would eliminate the logistical and cost issues associated with ice core management.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003AGUFMED51C1203S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003AGUFMED51C1203S&link_type=ABSTRACT"><span id="translatedtitle">Partnering With Scientists To Increase the Visibility and Use of Published Global Climate Change Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schmidt, L. J.; Scott, M.; Geiger-Wooten, N.; McCaffrey, M. S.; Anderson, D. M.; Eakin, C. M.</p> <p>2003-12-01</p> <p>Scientific journal articles are notoriously difficult for non-scientists or scientists outside a specialty to comprehend. Yet in societally relevant fields such as global climate change, there is an urgent need to make the published results of scientific research more accessible and useable to a broad audience. NOAA's World Data for <span class="hlt">Paleoclimatology</span> attempts to meet this need using the Internet to distribute raw data and information products from scientific publications. The Data Center creates "What's New" pages highlighting data from recent publications, along with descriptions and ancillary information such as photographs. The Data Center also authors a "Climate TimeLine", online slide sets and photo gallery, and "Paleo Perspectives" web pages that describe the broader significance of scientific research, and how the data are used to improve our understanding of global warming, drought, and climate change. With the goal to inform and engage, the Climate Time Line provides interactive activities, and information that can be integrated into the classroom. The approach benefits a diverse audience by demystifying climate science and making it more accessible, and benefits scientists by increasing the visibility and use of scientists' published data. The success of the approach can be seen in web site user statistics and comments, and numerous awards for providing valuable information via the Internet. To solve the challenge of simplifying complex scientific problems while maintaining the accuracy and integrity of the scientific information, the World Data Center works closely with scientists who contribute the data. Underlying the effort are the hundreds of scientists who have contributed their data to the World Data Center, and reviewed and edited the online extensions of their research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMNG22A..03M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMNG22A..03M"><span id="translatedtitle">Trends and Correlation Estimation in Climate Sciences: Effects of Timescale Errors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mudelsee, M.; Bermejo, M. A.; Bickert, T.; Chirila, D.; Fohlmeister, J.; Köhler, P.; Lohmann, G.; Olafsdottir, K.; Scholz, D.</p> <p>2012-12-01</p> <p>Trend describes time-dependence in the first moment of a stochastic process, and correlation measures the linear relation between two random variables. Accurately estimating the trend and correlation, including uncertainties, from climate time series data in the uni- and bivariate domain, respectively, allows first-order insights into the geophysical process that generated the data. Timescale errors, ubiquitious in <span class="hlt">paleoclimatology</span>, where archives are sampled for proxy measurements and dated, poses a problem to the estimation. Statistical science and the various applied research fields, including geophysics, have almost completely ignored this problem due to its theoretical almost-intractability. However, computational adaptations or replacements of traditional error formulas have become technically feasible. This contribution gives a short overview of such an adaptation package, bootstrap resampling combined with parametric timescale simulation. We study linear regression, parametric change-point models and nonparametric smoothing for trend estimation. We introduce pairwise-moving block bootstrap resampling for correlation estimation. Both methods share robustness against autocorrelation and non-Gaussian distributional shape. We shortly touch computing-intensive calibration of bootstrap confidence intervals and consider options to parallelize the related computer code. Following examples serve not only to illustrate the methods but tell own climate stories: (1) the search for climate drivers of the Agulhas Current on recent timescales, (2) the comparison of three stalagmite-based proxy series of regional, western German climate over the later part of the Holocene, and (3) trends and transitions in benthic oxygen isotope time series from the Cenozoic. Financial support by Deutsche Forschungsgemeinschaft (FOR 668, FOR 1070, MU 1595/4-1) and the European Commission (MC ITN 238512, MC ITN 289447) is acknowledged.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMED12A0157K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMED12A0157K"><span id="translatedtitle">The Development of a Climate Time Line Information Tool</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kowal, D.; McCaffery, M.; Anderson, D.; Habermann, D. E.</p> <p>2001-12-01</p> <p>The "Climate Time Line" or CTL tool currently in development at the National Geophysical Data Center will provide a climatic and "place-based" context for current weather patterns and a pre-instrumental context for current climate trends. Two audiences-GLOBE students and water managers involved with the Western Water Assessment--are targeted in the pilot project phase to test the CTL as a learning and decision-making support tool. Weather, climate and paleoclimatic observations will be integrated through a web-based interface that can be used for comparing data collected over 10 year, 100 year and 1000+ year periods, and made accessible and meaningful to non-technical users. The Climate Time Line prototype will include the following features: 1) Access to diverse data sets such as NCDC's Historic Climate Network, GLOBE Student Data Archive, World Data Center for <span class="hlt">Paleoclimatology</span> and historical streamflow data from the USGS; 2) Map Locator/Search Utility for regional inquiries and comparison views; 3) Varying temporal and spatial displays; 4) Tutorial and help sections to guide and support users; 5) Supporting materials including a "Powers of Ten" primer examining variability at various timescales; and 6) Statistical assessment tools. The CTL prototype offers a novel approach in the scientific analysis of climate and hydrology data. It will facilitate inquiries by simplifying access to environmental data. Additionally, it will provide historical timelines for the intended user to compare the development of human cultures in relation to climate trends and variability--promoting an inquiry-rich learning environment. Throughout the pilot project phase, the CTL will undergo evaluation particularly in the area of usability, followed by a pre- and post- assessment of its educational impact on the targeted, non-technical audience. A hypernews workspace has been created to facilitate the development of the CTL. >http://HyperNews.ngdc.noaa.gov/HyperNews/get/ ClimateTimelineProject.html.</a></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMIN41C1710A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMIN41C1710A&link_type=ABSTRACT"><span id="translatedtitle">EarthCube GeoLink: Semantics and Linked Data for the Geosciences</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arko, R. A.; Carbotte, S. M.; Chandler, C. L.; Cheatham, M.; Fils, D.; Hitzler, P.; Janowicz, K.; Ji, P.; Jones, M. B.; Krisnadhi, A.; Lehnert, K. A.; Mickle, A.; Narock, T.; O'Brien, M.; Raymond, L. M.; Schildhauer, M.; Shepherd, A.; Wiebe, P. H.</p> <p>2015-12-01</p> <p>The NSF EarthCube initiative is building next-generation cyberinfrastructure to aid geoscientists in collecting, accessing, analyzing, sharing, and visualizing their data and knowledge. The EarthCube GeoLink Building Block project focuses on a specific set of software protocols and vocabularies, often characterized as the Semantic Web and "Linked Data", to publish data online in a way that is easily discoverable, accessible, and interoperable. GeoLink brings together specialists from the computer science, geoscience, and library science domains, and includes data from a network of NSF-funded repositories that support scientific studies in marine geology, marine ecosystems, biogeochemistry, and <span class="hlt">paleoclimatology</span>. We are working collaboratively with closely-related Building Block projects including EarthCollab and CINERGI, and solicit feedback from RCN projects including Cyberinfrastructure for Paleogeosciences (C4P) and iSamples. GeoLink has developed a modular ontology that describes essential geoscience research concepts; published data from seven collections (to date) on the Web as geospatially-enabled Linked Data using this ontology; matched and mapped data between collections using shared identifiers for investigators, repositories, datasets, funding awards, platforms, research cruises, physical specimens, and gazetteer features; and aggregated the results in a shared knowledgebase that can be queried via a standard SPARQL endpoint. Client applications have been built around the knowledgebase, including a Web/map-based data browser using the Leaflet JavaScript library and a simple query service using the OpenSearch format. Future development will include extending and refining the GeoLink ontology, adding content from additional repositories, developing semi-automated algorithms to enhance metadata, and further work on client applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.C13C0839O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.C13C0839O"><span id="translatedtitle">Post-depositional migration and preservation of methanesulfonic acid (MSA) in polar ice cores</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Osman, M.; Marchal, O.; Guo, W.; Das, S. B.; Evans, M. J.</p> <p>2015-12-01</p> <p>Methanesulfonic acid (MSA; CH3SO3-) in ice cores is a unique, high-resolution proxy of regional sea ice behavior, marine primary productivity, and synoptic climatology. Significant uncertainties remain, however, in both our understanding of the production and transfer of MSA to the ice sheet, as well as its preservation over time, compromising the <span class="hlt">paleoclimatological</span> utility of the proxy. Here we apply a numerical modeling approach to quantitatively investigate the post-depositional processes affecting MSA migration and preservation within the firn and ice column, building on recent observational and theoretical studies. Our model allows us to evaluate the timing and magnitude of the vertical movement of MSA in response to varying influences, including the competing effects of 1) concentration gradients of sea-salts typically deposited asynchronously to MSA, 2) snow accumulation and densification rates, and 3) in situ temperature gradients. We first test the model against a recently collected ice core from a high accumulation site in coastal West Antarctica, where monthly-resolved MSA records show an abrupt shift from a summer-to-winter maximum in MSA at ~23m depth (ρ ≈ 650 kg/m3), near the firn-ice transition. We find our model to be a robust predictor of the observed migrational features in this record, capturing both (i) the abrupt shift in summer-to-winter maximal concentrations of MSA (steady state ≈ 3.2 yrs), and (ii) the depression of the seasonal amplitude at depth. Further, our modeling results suggest post-depositional effects can lead to substantial interannual alteration of the MSA signal, contrary to previous assumptions that MSA migration is confined within annual layers at high accumulation sites. Using a broad range of polar MSA records and their associated, site-specific environmental conditions, we will evaluate the fidelity of subannual to interannual variability of MSA records and systematically determine the factors conducive to its</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.1791S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.1791S"><span id="translatedtitle">Modelling stable water isotopes during "high-precipitation" events at Dome C, Antarctica</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schlosser, Elisabeth; Masson-Delmotte, Valérie; Risi, Camille; Stenni, Barbara; Valt, Mauro; Powers, Jordan G.; Manning, Kevin W.; Duda, Michael G.; Cagnati, Anselmo</p> <p>2014-05-01</p> <p>For a correct <span class="hlt">paleoclimatologic</span> interpretation of stable water isotopes from ice cores both pre- and post-depositional processes and their role for isotope fractionation have to be better understood. Our study focusses on "pre-depositional processes", namely the atmospheric processes that determine moisture transport and precipitation formation. At the deep ice core drilling site "Dome C", East Antarctica, fresh snow samples have been taken since 2006. These samples have been analysed crystallographically, which enables us to clearly distinguish between blowing snow, diamond dust, and "synoptic precipitation". Also the stable oxygen/hydrogen isotope ratios of the snow samples were measured, including measurements of 17-O. This is the first and only multi-year fresh-snow data series from an Antarctic deep drilling site. The Antarctic Mesoscale Prediction System (AMPS) employs Polar WRF for aviation weather forecasts in Antarctica. The data are archived and can be used for scientific purposes. The mesoscale atmospheric model was adapted especially for polar regions. The horizontal resolution for the domain that covers the Antarctic continent is 10 km. It was shown that precipitation at Dome C is temporally dominated by diamond dust. However, comparatively large amounts of precipitation are observed during several "high-precipitation" events per year, caused by synoptic activity in the circumpolar trough and related advection of relatively warm and moist air from lower latitudes to the interior of Antarctica. AMPS archive data are used to investigate the synoptic situations that lead to "high-precipitation" events at Dome C; in particular, possible moisture sources are determined using back-trajectories. With this meteorological information, the isotope ratios are calculated using two different isotope models, the Mixed Cloud Isotope Model, a simple Rayleigh-type model, and the LMDZ-iso (Laboratoire de Météorologie Dynamic Zoom), a General Circulation Model (GCM</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988EOSTr..69..654B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988EOSTr..69..654B"><span id="translatedtitle">Pacific neogene stratigraphy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barron, John; Beu, Alan; Blueford, Joyce R.; Chinzei, Kiyotaka; Hornibrook, Norcutt; Ingle, James; Steininger, Fritz; Tsuchi, Ryuichi</p> <p></p> <p>The Fourth International Congress of Pacific Neogene Stratigraphy, was held July 29-31, 1987, at the University of California, Berkeley. This very successful congress was organized by the Regional Committee on Pacific Neogene Stratigraphy (RCPNS) of the International Union of Geological Sciences (IUGS) and the International Geological Correlation Program (IGCP) Project 246 “Pacific Neogene Events in Time and Space.” The meeting was attended by 180 scientists from 16 different countries, and more than 90 presentations were made, on topics ranging from <span class="hlt">paleoclimatology</span>, biostratigraphy, regional stratigraphy and geologic history, new techniques in stratigraphy, evolutionary studies, and modern biofacies and sediment relationships.A. R. Edwards of the New Zealand Geological Survey (Lower Hutt, New Zealand) spoke on climatic events that he recognizes in the late Neogene strata of New Zealand. The carbon isotope shift during chron 6 (6.3-6.5 Ma) is identified in the sequence at Blind River (Marlborough, New Zealand). The extinction of ˜25% of New Zealand molluscan genera during the latest Micoene (Kapitean Stage) accompanied the greatly accelerated diversification of planktonic foraminifera lineages at this time. The New Zealand events are also coeval with the Messinian “salinity crisis” in the Mediterranean. A series of events (extinctions of Mollusca, appearance of glacial rock types, foraminifera speciation, and nannofossil appearances) in New Zealand late Pliocene rocks reflect the climatic deterioration. One type of sub-Antarctic molluscan fauna abruptly appeared in central North Island at 2.4 m.y., coeval with the onset of major Northern Hemisphere glaciation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRF..120..763B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRF..120..763B"><span id="translatedtitle">Impact of borehole depths on reconstructed estimates of ground surface temperature histories and energy storage</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beltrami, Hugo; Matharoo, Gurpreet S.; Smerdon, Jason E.</p> <p>2015-05-01</p> <p>Estimates of ground surface temperature changes and continental energy storage from geothermal data have become well-accepted indicators of climatic changes. These estimates are independent contributions to the ensemble of paleoclimatic reconstructions and have been used for the validation of general circulation models, and as a component of the energy budget accounting of the global climate system. Recent global and hemispheric analyses of geothermal data were based on data available in the borehole <span class="hlt">paleoclimatology</span> database, which contains subsurface temperature profiles from a minimum depth of 200 m to about 600 m. Because of the nature of heat conduction, different depth ranges contain the record of past and persistent changes in the energy balance between the lower atmosphere and the ground for different time periods. Here we examine the dependency of estimated ground surface temperature histories and the magnitude of the subsurface heat content on the depth of borehole temperature profiles. Our results show that uncertainties in the estimates of the long-term surface temperature are in the range of ±0.5K. We conclude that previous estimates of ground surface temperature change remain valid for the period since industrialization, but longer-term estimates are subject to considerable uncertainties. The subsurface heat content shows a larger range of variability arising from differences in depth of the borehole temperature profiles, as well as from differences in the time of data acquisition, spanning four decades. These results indicate that estimates of subsurface heat should be carried out with caution to decrease cumulative errors in any spatial analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMPP41D..03B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMPP41D..03B"><span id="translatedtitle">The Paleoclimate Reanalysis Project</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Browning, S. A.; Goodwin, I. D.</p> <p>2015-12-01</p> <p>Recent advances in proxy-model data assimilation have made feasible the development of global proxy-based reanalyses. Proxy-based reanalyses aim to make optimum use of both proxy and model data while presenting paleoclimate information in an accessible format—they will undoubtedly play a pivotal role in the future of paleoclimate research. In the Paleoclimate Reanalysis Project (PaleoR) we use 'off-line' data assimilation to constrain the CESM1(CAM5) Last Millennial Ensemble (LME) simulation with a globally distributed multivariate proxy dataset, producing a decadal resolution reanalysis of the past millennium. Discrete time periods are 'reconstructed' by using anomalous (±0.5σ) proxy climate signals to select an ensemble of climate state analogues from the LME. Prior to assimilation the LME simulates internal variability that is temporally inconsistent with information from the proxy archive. After assimilation the LME is highly correlated to almost all included proxy data, and dynamical relationships between modeled variables are preserved; thus providing a 'real-world' view of climate system evolution during the past millennium. Unlike traditional regression based approaches to <span class="hlt">paleoclimatology</span>, PaleoR is unaffected by temporal variations in teleconnection patterns. Indices representing major modes of global ocean-atmosphere climate variability can be calculated directly from PaleoR spatial fields. PaleoR derived ENSO, SAM, and NAO indices are consistent with observations and published multiproxy reconstructions. The computational efficiency of 'off-line' data assimilation allows easy incorporation and evaluation of new proxy data, and experimentation with different setups and model simulations. PaleoR is our first attempt at a global paleoclimate reanalysis and we have identified several opportunities for future improvements. PaleoR spatial fields can be viewed online at http://climatefutures.mq.edu.au/research/themes/marine/paleor/.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMPP51A2245H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMPP51A2245H&link_type=ABSTRACT"><span id="translatedtitle">Treating pre-instrumental data as "missing" data: using a tree-ring-based paleoclimate record and imputations to reconstruct streamflow in the Missouri River Basin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ho, M. W.; Lall, U.; Cook, E. R.</p> <p>2015-12-01</p> <p>Advances in <span class="hlt">paleoclimatology</span> in the past few decades have provided opportunities to expand the temporal perspective of the hydrological and climatological variability across the world. The North American region is particularly fortunate in this respect where a relatively dense network of high resolution paleoclimate proxy records have been assembled. One such network is the annually-resolved Living Blended Drought Atlas (LBDA): a paleoclimate reconstruction of the Palmer Drought Severity Index (PDSI) that covers North America on a 0.5° × 0.5° grid based on tree-ring chronologies. However, the use of the LBDA to assess North American streamflow variability requires a model by which streamflow may be reconstructed. Paleoclimate reconstructions have typically used models that first seek to quantify the relationship between the paleoclimate variable and the environmental variable of interest before extrapolating the relationship back in time. In contrast, the pre-instrumental streamflow is here considered as "missing" data. A method of imputing the "missing" streamflow data, prior to the instrumental record, is applied through multiple imputation using chained equations for streamflow in the Missouri River Basin. In this method, the distribution of the instrumental streamflow and LBDA is used to estimate sets of plausible values for the "missing" streamflow data resulting in a ~600 year-long streamflow reconstruction. Past research into external climate forcings, oceanic-atmospheric variability and its teleconnections, and assessments of rare multi-centennial instrumental records demonstrate that large temporal oscillations in hydrological conditions are unlikely to be captured in most instrumental records. The reconstruction of multi-centennial records of streamflow will enable comprehensive assessments of current and future water resource infrastructure and operations under the existing scope of natural climate variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.B31C..03W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.B31C..03W"><span id="translatedtitle">Fast Vegetational Responses to Late-Glacial Climate Change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Williams, J. W.; Post, D. M.; Cwynar, L. C.; Lotter, A. F.; Levesque, A. J.</p> <p>2001-12-01</p> <p>How rapidly can natural ecosystems respond to rapid climate change? This question can be addressed by studying paired paleoecological and <span class="hlt">paleoclimatological</span> records spanning the last deglaciation. Between 16 and 10 ka, abrupt climatic oscillations (e.g. Younger Dryas, Gerzensee/Killarney Oscillations) interrupted the general warming trend. Rates of climate change during these events were as fast or faster than projected rates of change for this century. We compiled a dozen high-resolution lacustrine records in North America and Europe with a pollen record and independent climatic proxy, a clear Younger Dryas signal, and good age control. Cross-correlation analysis suggests that vegetation responded rapidly to late-glacial climate change, with significant changes in vegetation composition occurring within the lifespan of individual trees. At all sites, vegetation lagged climate by less than 200 years, and at two-thirds of the sites, the initial vegetational response occurred within 100 years. The finding of rapid vegetational responses is consistent across sites and continents, and is similar to the 100-200 year response times predicted by gap-scale forest models. Likely mechanisms include 1) increased susceptibility of mature trees to disturbances such as fire, wind, and disease, thereby opening up gaps for colonization, 2) the proximity of these sites to late-glacial treeline, where climate may directly control plant population densities and range limits, 3) the presence of herbaceous taxa with short generation times in these plant communities, and 4) rapid migration due to rare long-distance seed dispersals. Our results are consistent with reports that plant ranges are already shifting in response to recent climate change, and suggest that these shifts will persist for the next several centuries. Widespread changes in plant distributions may affect surface-atmosphere interactions and will challenge attempts to manage ecosystems and conserve biodiversity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMPP41D1427L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMPP41D1427L"><span id="translatedtitle">Probabilistic Generative Models for the Statistical Inference of Unobserved Paleoceanographic Events: Application to Stratigraphic Alignment for Inference of Ages</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lawrence, C.; Lin, L.; Lisiecki, L. E.; Khider, D.</p> <p>2014-12-01</p> <p>The broad goal of this presentation is to demonstrate the utility of probabilistic generative models to capture investigators' knowledge of geological processes and proxy data to draw statistical inferences about unobserved <span class="hlt">paleoclimatological</span> events. We illustrate how this approach forces investigators to be explicit about their assumptions, and about how probability theory yields results that are a mathematical consequence of these assumptions and the data. We illustrate these ideas with the HMM-Match model that infers common times of sediment deposition in two records and the uncertainty in these inferences in the form of confidence bands. HMM-Match models the sedimentation processes that led to proxy data measured in marine sediment cores. This Bayesian model has three components: 1) a generative probabilistic model that proceeds from the underlying geophysical and geochemical events, specifically the sedimentation events to the generation the proxy data Sedimentation ---> Proxy Data ; 2) a recursive algorithm that reverses the logic of the model to yield inference about the unobserved sedimentation events and the associated alignment of the records based on proxy data Proxy Data ---> Sedimentation (Alignment) ; 3) an expectation maximization algorithm for estimating two unknown parameters. We applied HMM-Match to align 35 Late Pleistocene records to a global benthic d18Ostack and found that the mean width of 95% confidence intervals varies between 3-23 kyr depending on the resolution and noisiness of the core's d18O signal. Confidence bands within individual cores also vary greatly, ranging from ~0 to >40 kyr. Results from this algorithm will allow researchers to examine the robustness of their conclusions with respect to alignment uncertainty. Figure 1 shows the confidence bands for one low resolution record.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27039853','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27039853"><span id="translatedtitle">THE BIOGEOGRAPHIC ORIGIN OF ARCTIC ENDEMIC SEAWEEDS: A THERMOGEOGRAPHIC VIEW(1).</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Adey, Walter H; Lindstrom, Sandra C; Hommersand, Max H; Müller, Kirsten M</p> <p>2008-12-01</p> <p>The Arctic is geologically and biogeographically young, and the origin of its seaweed flora has been widely debated. The Arctic littoral biogeographic region dates from the latest Tertiary and Pleistocene. Following the opening of Bering Strait, about 3.5 mya, the "Great Trans-Arctic Biotic Interchange" populated the Arctic with a fauna strongly dominated by species of North Pacific origin. The Thermogeographic Model (TM) demonstrates why climate and geography continued to support this pattern in the Pleistocene. Thus, Arctic and Atlantic subarctic species of seaweeds are likely to be evolutionarily "based" in the North Pacific, subarctic species are likely to be widespread in the warmer Arctic, and species of Atlantic Boreal or warmer origin are unlikely in the Arctic and Subarctic. Although Arctic seaweeds have been thought to have a greater affinity with the North Atlantic, we have reanalyzed the Arctic endemic algal flora, using the Thermogeographic Model and evolutionary trees based on molecular data, to demonstrate otherwise. There are 35 congeneric species of the six, abundant Arctic Rhodophyta that we treat in this paper; 32 of these species (91%) occur in the North Pacific, two species (6%) occur in the Boreal or warmer Atlantic Ocean, and a single species is panoceanic, but restricted to the Subarctic. Laminaria solidungula J. Agardh, a kelp Arctic "endemic" species, has 18 sister species. While only eleven (61%) occur in the North Pacific, this rapidly dispersing and evolving genus is a terminal member of a diverse family and order (Laminariales) widely accepted to have evolved in the North Pacific. Thus, both the physical/time-based TM and the dominant biogeographic pattern of relatives of Arctic macrophytes suggest strong compliance with the evidence of zoology, geology, and <span class="hlt">paleoclimatology</span> that the Arctic marine flora is largely of Pacific origin. PMID:27039853</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMPP31C1885G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMPP31C1885G"><span id="translatedtitle">Geomorphical and Geochronological Constrains of the Last Glacial Period in Southern Patagonia, Southern South America</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>García, J.; Hall, B. L.; Kaplan, M. R.; Vega, R. M.; Binnie, S. A.; Hein, A.; Gómez, G. N.; Ferrada, J. J.</p> <p>2013-12-01</p> <p>Despite the outer limits of the former Patagonian ice sheet (PIS, ~38-55S) having been extensively mapped, it remains unknown if the Patagonian glaciers fluctuated synchronously or asynchronously during the last glacial period. Previous work has revealed asynchronous spatiotemporal ice dynamics along the eastern and western ice-margins at the end of the last glaciation but it is not well understood if the northern and southern parts of the PIS reached concurrent maximum glaciation during the last glacial cycle. The Patagonian Andes is the only landmass involving the southern westerly wind belt latitudinal range, which is thought to have played a key role in past glacial and climate changes. Therefore, reconstructing southern Andes glacier history constitutes a key element for understanding the cause of glaciations in Patagonia and the role of the westerlies in climate change. Here, we discuss paleoglaciological and <span class="hlt">paleoclimatological</span> implications of new 10Be and 14C data obtained from moraines and strategically selected mires in two contiguous glacially molded basins of south Patagonia (48-55S): Torres del Paine (51S) and Última Esperanza (52S). In this region, we focused our 10Be cosmogenic-dating efforts in the previously undated outer moraines deposited (supposedly) during the last glacial cycle. In order to crosscheck cosmogenic data we collected boulders embedded in moraines and cobbles from the main glaciofluvial plains grading from the outermost moraines. Geomorphic and cosmogenic dating affords evidence for glacial maximum conditions occurring between 40-50 ka (ka = thousand of years before present) in southern Patagonia, which is different from other chronologies within southern South America. We obtained 14C basal ages from sites located within moraine depressions and on former paleolake shorelines and thus these may provide key data on deglaciation and debated regional paleolake history.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFMED12A0119S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFMED12A0119S"><span id="translatedtitle">Petroleum Geoscience Program at University of Oklahoma: 25 Years of Change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Slatt, R. M.; Clopine, W. W.</p> <p>2003-12-01</p> <p>The School of Geology and Geophysics at the University of Oklahoma has a long history and tradition of petroleum geoscience education and research. The 1980's and early 1990's downturn in the petroleum industry resulted in significantly fewer students seeking petroleum industry education and careers. Like many U.S. earth science departments, the School looked to geochemistry and hard rock geology to help fill the void. While this new emphasis complimented previous strengths by providing a solid foundation for earth science students, there were unintended consequences. Limited departmental resources caused a rift between traditional and new directions. Many incoming students found course work and faculty research interests differed from those in published recruiting materials. The relative merits of industry support vs academic research grants became an issue in employment decisions. Industry recruiters no longer felt they were working in partnership with the School. Many companies stopped recruiting at Oklahoma, alienating students and past/future alumni. In the mid- to late-1990's the leadership and faculty of the School found a more constructive balance, with strong support from a committed base of alumni. Two senior academic Chairs were filled by faculty with applied research interests and industry experience. In 2000, a third faculty member with a similar background became Director of the School. These additions provided a significant boost to the existing petroleum geoscience program. Other faculty hires provided new basic research directions such as <span class="hlt">paleoclimatology</span>. These improvements have strengthened both industry and alumni support for the School, and have revived the image of a petroleum emphasis. There is now a very strong list of petroleum-oriented course offerings, improved interaction with the university's petroleum engineering school, company recruiters have returned in force, and alumni support has improved dramatically. At a time of decreasing</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2940817','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2940817"><span id="translatedtitle">Phylogenetic relationships and biogeographical patterns in Circum-Mediterranean subfamily Leuciscinae (Teleostei, Cyprinidae) inferred from both mitochondrial and nuclear data</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2010-01-01</p> <p> <span class="hlt">paleoclimatological</span> and hydrogeological history of Mediterranean region. We propose different colonization models of Mediterranean region during the early Oligocene. Later vicariance events promoted Leuciscinae diversification during Oligocene and Miocene periods. Our data corroborate the presence of leuciscins in North Africa before the Messinian salinity crisis. Indeed, Messinian period appears as a stage of gradually Leuciscinae diversification. The rise of humidity at the beginning of the Pliocene promoted the colonization and posterior isolation of newly established freshwater populations. Finally, Pleistocene glaciations determined the current European distribution of some leuciscine species. PMID:20807419</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMPP33A2111D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMPP33A2111D"><span id="translatedtitle">A multiple-proxy approach to understanding rapid Holocene climate change in Southeast Greenland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Davin, S. H.; Bradley, R. S.; Balascio, N. L.; de Wet, G.</p> <p>2012-12-01</p> <p>The susceptibility of the Arctic to climate change has made it an excellent workshop for <span class="hlt">paleoclimatological</span> research. Although there have been previous studies concerning climate variability carried out in the Arctic, there remains a critical dearth of knowledge due the limited number of high-resolution Holocene climate-proxy records available from this region. This gap skews our understanding of observed and predicted climate change, and fuels uncertainty both in the realms of science and policy. This study takes a comprehensive approach to tracking Holocene climate variability in the vicinity of Tasiilaq, Southeast Greenland using a ~5.6 m sediment core from Lower Sermilik Lake. An age-depth model for the core has been established using 8 radiocarbon dates, the oldest of which was taken at 4 m down core and has been been dated to approximately 6.2 kyr BP. The bottom meter of the core below the final radiocarbon date contains a transition from cobbles and coarse sand to organic-rich laminations, indicating the termination of direct glacial influence and therefore likely marking the end of the last glacial period in this region. The remainder of the core is similarly organic-rich, with light-to-dark brown laminations ranging from 0.5 -1 cm in thickness and riddled with turbidites. Using this core in tandem with findings from an on-site assessment of the geomorphic history of the locale we attempt to assess and infer the rapid climatic shifts associated with the Holocene on a sub-centennial scale. Such changes include the termination of the last glacial period, the Mid-Holocene Climatic Optimum, the Neoglacial Period, the Medieval Climatic Optimum, and the Little Ice Age. A multiple proxy approach including magnetic susceptibility, bulk organic geochemistry, elemental profiles acquired by XRF scanning, grain-size, and spectral data will be used to characterize the sediment and infer paleoclimate conditions. Additionally, percent biogenic silica by weight has been</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA.....6685D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA.....6685D"><span id="translatedtitle">Lake beds in the Yammouneh basin (Lebanon) record more than 12,000 years of seismic history on the Levant fault</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Daëron, M.; Klinger, Y.; Tapponnier, P.; Elias, A.; Gasse, F.; Sursock, A.; Brax, M.; Jacques, E.; Nemer, T.</p> <p>2003-04-01</p> <p>The most active seismogenic structure along the eastern shore of the Mediterranean is the Levant fault, which forms the boundary between the African and Arabian plates. In order to study the seismic history of this fault on a millennial time scale in Lebanon, we excavated a series of trenches in the Yammouneh basin, where the active trace of the fault cuts through late Pleistocene lacustrine sediments. Five trench walls across the fault zone, 4m apart from each other, were logged and mapped in 2002 and compared to an exploratory, 5m-deep trench dug in 2001. The walls expose subtabular lake beds, down to a depth of 10.5m, with 2-3m of white, shell-rich calcareous marls that overlie 6-7m of blue-grey clays, oxydized to red brown at shallow depth, that top 1-1.5m of light blue marls. The first-order sedimentary units in the 2002 trench are nearly identical to the units exposed in 2001, implying that the variations in the stratigraphy are climate-driven. The stratigraphic layers, which include finely laminated subunits, are cut and disturbed by coseismic deformation along two subparallel, 1-3m-wide, vertical fault zones, 5-10m apart. The cumulative, apparent vertical offsets of corresponding layers at the base of the deepest walls reach 1.5m. Mapping and comparing the fault splays and apparent offsets (still in progress) on all the trench walls suggests the occurrence of about 20 distinct seismic events. Radiocarbon dating of the stratigraphic sequence is underway. Preliminary dating results confirm that here, the latest earthquake along the Yammouneh fault occurred before the 14th century AD, and suggest 7 interseismic periods in the 11ky preceding that event (likely the 1202 AD earthquake). This would be consistent with a preliminary, average recurrence time of 1500-1600 years. An ongoing <span class="hlt">paleoclimatologic</span> study of the stratigraphic log should yield more accurate insight into the late Pleistocene climate of the Middle-East, and better constraints on the ages of event</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.H54C..03B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.H54C..03B"><span id="translatedtitle">Mass-Dependent and -Independent Fractionation of Mercury Isotopes in Aquatic Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bergquist, B. A.; Joel, B. D.; Jude, D. J.</p> <p>2008-12-01</p> <p>Mercury is a globally distributed and highly toxic pollutant. Although Hg is a proven health risk, much of the natural cycle of Hg is not well understood and new approaches are needed to track Hg and the chemical transformations it undergoes in the environment. Recently, we demonstrated that Hg isotopes exhibit two types of isotope fractionation: (1) mass dependent fractionation (MDF) and (2) mass independent fractionation (MIF) of only the odd isotopes (Bergquist and Blum, 2007). The observation of large MIF of Hg isotopes (up to 5 permil) is exciting because only a few other isotopic systems have been documented to display large MIF, the most notable of which are oxygen and sulfur. In both cases, the application of MIF has proven very useful in a variety of fields including cosmochemistry, <span class="hlt">paleoclimatology</span>, physical chemistry, atmospheric chemistry, and biogeochemistry. Both MDF and MIF isotopic signatures are observed in natural samples, and together they open the door to a new method for tracing Hg pollution and for investigating Hg behavior in the environment. For example, fish record MDF that appears to be related to size and age. Additionally, fish display MIF signatures that are consistent with the photo-reduction of methylmercury (Bergquist and Blum, 2007). If the MDF and MIF in ecosystems can be understood, the signatures in fish could inform us about the sources and processes transforming Hg and why there are differences in the bioaccumulation of Hg in differing ecosystems and populations of fish. This requires sampling of a variety of ecosystems, the sampling of many components of the ecosystems, and the use of other tracers such as carbon and nitrogen isotopes. We have expanded our studies of aquatic ecosystems to include several lakes in North America. Similar to other isotopic systems used to study food web dynamics and structure (i.e., C and N), the MDF of Hg in fish appears to be related to size and age. The MDF recorded in fish likely reflects</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMPP11A2204M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMPP11A2204M&link_type=ABSTRACT"><span id="translatedtitle">The CREp program, a fully parameterizable program to compute exposure ages (3He, 10Be)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martin, L.; Blard, P. H.; Lave, J.; Delunel, R.; Balco, G.</p> <p>2015-12-01</p> <p>Over the last decades, cosmogenic exposure dating permitted major advances in Earth surface sciences, and particularly in <span class="hlt">paleoclimatology</span>. Yet, exposure age calculation is a dense procedure. It requires numerous choices of parameterization and the use of an appropriate production rate. Nowadays, Earth surface scientists may either calculate exposure ages on their own or use the available programs. However, these programs do not offer the possibility to include all the most recent advances in Cosmic Ray Exposure (CRE) dating. Notably, they do not propose the most recent production rate datasets and they only offer few possibilities to test the impact of the atmosphere model and the geomagnetic model on the computed ages. We present the CREp program, a Matlab © code that computes CRE ages for 3He and 10Be over the last 2 million years. The CREp program includes the scaling models of Lal-Stone in the "Lal modified" version (Balco et al., 2008; Lal, 1991; Stone, 2000) and the LSD model (Lifton et al., 2014). For any of these models, CREP allows choosing between the ERA-40 atmosphere model (Uppala et al., 2005) and the standard atmosphere (National Oceanic and Atmospheric Administration, 1976). Regarding the geomagnetic database, users can opt for one of the three proposed datasets: Muscheler et al. 2005, GLOPIS-75 (Laj et al. 2004) and the geomagnetic framework proposed in the LSD model (Lifton et al., 2014). They may also import their own geomagnetic database. Importantly, the reference production rate can be chosen among a large variety of possibilities. We made an effort to propose a wide and homogenous calibration database in order to promote the use of local calibration rates: CREp includes all the calibration data published until July 2015 and will be able to access an updated online database including all the newly published production rates. This is crucial for improving the ages accuracy. Users may also choose a global production rate or use their own data</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.B23C0472H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.B23C0472H"><span id="translatedtitle">Density Banding in Coral Skeletons: A Biotic Response to Sea Surface Temperature?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hill, C. A.; Oehlert, A. M.; Piggot, A. M.; Yau, P. M.; Fouke, B. W.</p> <p>2008-12-01</p> <p>Density bands in the CaCO3 (aragonite) skeleton of scleractinian corals are commonly used as chronometers, where crystalline couplets of high and low density bands represent the span of one year. This provides a sensitive reconstructive tool for paleothermometry, <span class="hlt">paleoclimatology</span> and paleoecology. However, the detailed mechanisms controlling aragonite nucleation and crystallization events and the rate of skeletal growth remain uncertain. The organic matrix, composed of macromolecules secreted by the calicoblastic ectoderm, is closely associated with skeletal precipitation and is itself incorporated into the skeleton. We postulate that density banding is primarily controlled by changes in the rate of aragonite crystal precipitation mediated by the coral holobiont response to changes in sea surface temperature (SST). To test this hypothesis, data were collected from coral skeleton-tissue biopsies (2.5 cm in diameter) extracted from four species of Montastraea growing on the fringing reef tract of Curacao, Netherlands Antilles (annual mean variation in SST is 29° C in mid-September to 26° C in late February). Samples were collected in the following three contextual modes: 1) at two sites (Water Plant and Playa Kalki) along a lateral 25 km spatial transect; 2) across a vertical bathymetric gradient from 5 to 15 m water depth at each site; and 3) at strategic time periods spanning the 3° C annual variations in SST. Preliminary results indicate that skeletal density banding is also expressed in the organic matrix, permitting biochemical characterization and correlation of the organic matrix banding to the skeletal banding. In addition, both surficial and ectodermal mucins were characterized in terms of total protein content, abundance and location of their anionic, cationic, and neutral macromolecular constituents. Furthermore, the ratio of mucocytes in the oral ectoderm to gastrodermal symbiotic zooxanthellae has permitted estimates of seasonal carbon allocation by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMPP43B1675S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMPP43B1675S"><span id="translatedtitle">Calcareous sinter from ancient aqueducts as a source of data in paleoclimate, tectonics and hydrology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Surmelihindi, G.; Passchier, C. W.</p> <p>2010-12-01</p> <p>During the lifetime the Roman Empire (300BC-400AD), about 1200 major aqueducts were built to supply cities in the Mediterranean with drinking water. The ruins of many of these channels contain sinter (calcium carbonate), which was deposited at a rate of 0.5-5 mm/year over the life of the aqueduct, usually 50-200 but up to 1000 years. Calcareous sinter inside the ancient aqueduct channels can give important insight into <span class="hlt">paleoclimatology</span> in the form of temperature and rainfall, reflect palaeohydrology of water, water chemistry, flow rate, bacterial activity and source area of the water. This type of data is important to build climate models and to understand earthquake and flood patterns in the Mediterranean, and can be a new, additional source of information besides speleothems, travertine and tufa deposits. In our study we focus on Mediterranean climate patterns, and selected four aqueduct sites from Southern Turkey, Greece and Italy. The calcareous sinter deposits may reflect annual or subannual lamination characterized by alternating light, dense, coarse-grained and dark, porous, microcrystalline layers which are thought to represent winter and summer conditions respectively. Moreover, abrupt changes in the sequence of lamination can be a signal of natural hazards such as earthquakes or flood events. Deposits from the aqueduct of Patara (Southern Turkey) show 40-50 laminae couples, which may be annual layers. δ18O and δ 13C stable isotope data indicate high cyclicity within the sinter samples from Patara during the Roman period. Higher δ18O values correspond with dark, porous layers and lower values with light, dense layers. Major geochemical analyses show similar seasonal changes. Electron microprobe study shows that within dark laminae, detrital Fe, Mg, K, Al and Si are enriched whereas the light layers have high Ca content. Trace element analyses by LA-ICP-MS also indicate higher Mg/Ca and Sr/Ca values in the dark layers, which can be interpreted in terms</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMPP23A1730B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMPP23A1730B"><span id="translatedtitle">A high resolution, one million year record of extraterrestrial 3Helium from the Shatsky Rise (site 1209) following the K/T impact</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bhattacharya, A.; Mukhopadhyay, S.; Hull, P. M.; Norris, R. D.</p> <p>2010-12-01</p> <p>strange interval’ is 721 kyrs and not 450 kyrs as previously suggested based on astronomical tuning [1]. Hence, our results indicate that there are significant differences between the astronomically tuned timescale [1] and the 3He-derived timescale over the first million years following the K-T impact event. [1] Westerhold et al. Paleogeography, <span class="hlt">paleoclimatology</span>,paleoecology vol 257. pp373. 2008. [2] Mukhopadhyay et al. Geochimica Cosmochimica Acta. Vol 65. pp 653. 2001.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.7875P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.7875P"><span id="translatedtitle">Long continental pollen record of the last ca. 500 ka in eastern Anatolia - First palynological results from Lake Van cores obtained in 2010</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pickarski, N.; Heumann, G.; Litt, T.</p> <p>2012-04-01</p> <p>Lake Van is located in a climatically sensitive semiarid and tectonically active region in Eastern Anatolia, Turkey. It is a key site to reconstruct terrestrial paleoecology and paleoclimate in the Near East during the Quaternary. Lake Van is the largest soda lake (surface area 3.570 km2) and the fourth largest terminal lake in the world (volume 607 km3). The maximum water depth is 460 m and the maximum length is 130 km WSW-ENE. The present lake level is at an elevation of 1,646 m above mean sea level. The northern and eastern part of Lake Van is mainly characterized by steppe vegetation related to the so-called Irano-Turanian plant geographical territory. In contrast, some remnants of deciduous oak forests can be observed mainly in the Bitlis Massive, SW of the lake. We present preliminary palynological results of a long continental sedimentary record obtained during a coring campaign supported by the International Continental Scientific Drilling Program (ICDP) in summer 2010. The composite profile from the Ahlat Ridge, the most important site for <span class="hlt">paleoclimatological</span> studies (total length of ca. 218 m), yields a continuous paleoclimate archive encompassing ca. 500.000 years. The record is partly characterized by annually laminated sediments. By using pollen analysis, several glacial and interglacial/ interstadial periods can be observed. The warm stages can be identified based on higher amounts of pollen from thermophilous trees such as deciduous oak. In addition to the current interglacial stage (MIS 1), pronounced warm phases coincide with past interglacials probably correlative to MIS 5, 7, 9 and 11 or 13. Cold stages are characterized by pollen types related to steppe plants such as Artemisia, chenopods and grasses. The glacial-interglacial cycles as reflected in the palynological data are in broad agreement with those of stable oxygen isotope analyses based on autigenic carbonate of the lacustrine sediments (bulk). Caused by the state of the art, more</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.2624W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.2624W"><span id="translatedtitle">Robustness of Well-Verified, Spatially-Explicit High Resolution Climate Reconstructions: Characterization of Issues and Potential for Their Resolution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wahl, E. R.; Anchukaitis, K. J.; Frank, D.</p> <p>2009-04-01</p> <p>High-resolution, spatially-explicit reconstructions of climate over the past 1-2 millennia offer the potential to achieve two key goals of <span class="hlt">paleoclimatology</span>: 1) joining the instrumental and paleo records in a systematic way, to facilitate an extended synoptic-scale perspective on climate variability at regional scales; and 2) elucidating spatial patterns of the response to forcing changes over much longer time spans than possible with instrumental data, allowing for a greater range of responses to be included in composite analyses of forcings impacts on climate. A suite of spatially-explicit reconstruction methods coupled with experimental examination of long-term reconstruction performance in climate model simulation environments now provide a rich set of resources with which to move towards these goals, and also to examine likely situations of good and poor performance. A key concern of all paleo-reconstruction methods is that even well-calibrated and well-verified models of the same phenomenon over the same spatial and temporal domains can diverge outside of the calibration and verification periods. Divergence can occur simply by altering proxy data richness within the same reconstruction model. This suite of problems is relatively well characterized for regional, hemispheric, and global average temperature time series, and even has a well-known visual representation - the so-called "spaghetti diagrams". These issues also exist in spatially-explicit reconstructions, but are not as well characterized as they are for spatially-averaged time series; their potential impacts on achieving the goals described above are also not as well understood. We present examples of these issues from our current work in western North America and the South Asia/Indian Ocean region, along with ways to better characterize and deal with them. An intensive empirical approach is taken that examines a large variety of reconstruction situations for a given spatial-temporal domain - using</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010AGUFMPP11A1415H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010AGUFMPP11A1415H&link_type=ABSTRACT"><span id="translatedtitle">Coral Skeleton Density Banding: Biotic Response to Changes in Sea Surface Temperature</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hill, C. A.; Sivaguru, M.; Fried, G. A.; Fouke, B. W.</p> <p>2010-12-01</p> <p>Density bands in the CaCO3 (aragonite) skeleton of scleractinian corals are commonly used as chronometers, where crystalline couplets of high and low density bands represent the span of one year. Isotopic analysis of these density bands provides a sensitive reconstructive tool for <span class="hlt">paleoclimatology</span> and paleoecology. However, the detailed biotic mechanisms controlling coral skeleton aragonite nucleation and crystallization events and resulting skeletal growth rate remain uncertain. The coral tissue organic matrix, composed of macromolecules secreted by the calicoblastic ectoderm, is closely associated with skeletal precipitation and is itself incorporated into the skeleton. We postulate that density banding is primarily controlled by changes in the rate of aragonite crystal precipitation mediated by the coral holobiont response to changes in sea surface temperature (SST). To test this hypothesis, data were collected from coral skeleton-tissue biopsies (2.5 cm in diameter) extracted from four species of Montastraea growing on the fringing reef tract of Curacao, Netherlands Antilles. Annual mean variation in SST on Curacao range from 29o in mid-September to 26o C in late February. Samples were collected at strategic time periods spanning the 3o C annual variations in SST. Our nanometer-scale optical analyses of skeletal morphology have revealed consistent changes between high- and low-skeletal density bands, resulting in an 11% increase in the volume of aragonite precipitated in high-density skeletal bands. The re-localization and/or change in abundance of mucus, carbonic anhydrase (a molecule that catalyzes the hydration of carbon dioxide), calmodulin (a calcium-binding protein) and the change in density of gastrodermal symbiotic dinoflagellates has permitted estimates of seasonally-fluctuating carbon allocation by the coral holobiont in response to changing environmental conditions. This digital reconstruction of over 2000 images of one-micron-thick histological</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AN....334..576L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AN....334..576L"><span id="translatedtitle">Habitability and Multistability in Earth-like Planets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lucarini, V.; Pascale, S.; Boschi, R.; Kirk, E.; Iro, N.</p> <p>2013-06-01</p> <p>In this paper we explore the potential multistability of the climate for a planet around the habitable zone. We focus on conditions reminiscent to those of the Earth system, but our investigation has more general relevance and aims at presenting a general methodology for dealing with exoplanets. We describe a formalism able to provide a thorough analysis of the non-equilibrium thermodynamical properties of the climate system and explore, using a flexible climate model, how such properties depend on the energy input of the parent star, on the infrared atmospheric opacity, and on the rotation rate of the planet. We first show that it is possible to reproduce the multi-stability properties reminiscent of the <span class="hlt">paleoclimatologically</span> relevant snowball (SB)-warm (W) conditions. We then characterise the thermodynamics of the simulated W and SB states, clarifying the central role of the hydrological cycle in shaping the irreversibility and the efficiency of the W states, and emphasizing the extreme diversity of the SB states, where dry conditions are realized. Thermodynamics provides the clue for studying the tipping points of the system and leads us to constructing empirical parametrizations allowing for expressing the main thermodynamic properties as functions of the emission temperature of the planet only. Such empirical functions are shown to be rather robust with respect to changing the rotation rate of the planet from the current terrestrial one to half of it. Furthermore, we explore the dynamical range where the length of the day and the length of the year are comparable. We clearly find that there is a critical rotation rate below which the multi-stability properties are lost, and the ice-albedo feedback responsible for the presence of SB and W conditions is damped. The bifurcation graph of the system suggests the presence of a phase transition in the planetary system. Such critical rotation rate corresponds roughly to the phase-lock 2:1 condition. Therefore, if an</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMPP44B..02M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMPP44B..02M"><span id="translatedtitle">The PAGES 2k Global Multiproxy Database for Temperature Reconstructions of the Common Era</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McKay, N.; Emile-Geay, J.</p> <p>2015-12-01</p> <p>In 2013 the PAGES 2k Consortium released a paleo-temperature database with more than 500 records from 7 continental-scale regions, along with continental-scale temperature reconstructions derived independent by expert groups for each region. A major motivation of this effort was to increase the amount of regional expertise involved in identifying and evaluating paleoclimate records for their use in temperature reconstructions. The project highlighted the value of engaging regionally-based expertise in <span class="hlt">paleoclimatology</span>; however, the resulting database was somewhat disjoint, as each group assembled data independently with somewhat distinct goals and criteria, which hindered the use of the database to answer questions that span across multiple regions. Moreover, key data (e.g., native measurements, chronological uncertainties) and metadata (e.g., seasonality) were not included. Phase 2 of the PAGES 2k temperature database improves upon these shortcomings with a community-built flexible database that can be used to address major questions about the climate of the Common Era, and to refine the methodologies used to reconstruct it. As in phase 1, the database was built upon the expertise of dozens of paleclimatologists whose regional expertise spans the globe. Phase 2 of the temperature database includes about 800 temperature-sensitive timeseries, derived from ten archive types, including from the oceans. Here we present the characteristics and structure of the database, including a suite of diagnostics used to evaluate the fidelity of the temperature signal in the data. This includes their correlation with instrumental temperature data; however this assessment is not possible with all the records in the database, and we also recognize that such correlations are an imperfect metric of how strongly a timeseries reflects temperature throughout the Common Era. Consequently, we also explore other metrics, including how well each record corresponds with with nearby sites back</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70173713','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70173713"><span id="translatedtitle">Relations between rainfall–runoff-induced erosion and aeolian deposition at archaeological sites in a semi-arid dam-controlled river corridor</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Collins, Brian; Bedford, David; Corbett, Skye; Fairley, Helen; Cronkite-Ratcliff, Collin</p> <p>2016-01-01</p> <p>Process dynamics in fluvial-based dryland environments are highly complex with fluvial, aeolian, and alluvial processes all contributing to landscape change. When anthropogenic activities such as dam-building affect fluvial processes, the complexity in local response can be further increased by flood- and sediment-limiting flows. Understanding these complexities is key to predicting landscape behavior in drylands and has important scientific and management implications, including for studies related to <span class="hlt">paleoclimatology</span>, landscape ecology evolution, and archaeological site context and preservation. Here we use multi-temporal LiDAR surveys, local weather data, and geomorphological observations to identify trends in site change throughout the 446-km-long semi-arid Colorado River corridor in Grand Canyon, Arizona, USA, where archaeological site degradation related to the effects of upstream dam operation is a concern. Using several site case studies, we show the range of landscape responses that might be expected from concomitant occurrence of dam-controlled fluvial sand bar deposition, aeolian sand transport, and rainfall-induced erosion. Empirical rainfall-erosion threshold analyses coupled with a numerical rainfall–runoff–soil erosion model indicate that infiltration-excess overland flow and gullying govern large-scale (centimeter- to decimeter-scale) landscape changes, but that aeolian deposition can in some cases mitigate gully erosion. Whereas threshold analyses identify the normalized rainfall intensity (defined as the ratio of rainfall intensity to hydraulic conductivity) as the primary factor governing hydrologic-driven erosion, assessment of false positives and false negatives in the dataset highlight topographic slope as the next most important parameter governing site response. Analysis of 4+ years of high resolution (four-minute) weather data and 75+ years of low resolution (daily) climate records indicates that dryland erosion is dependent on short</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMPP21B1320N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMPP21B1320N"><span id="translatedtitle">The Svalbard Barents Sea Ice Sheet deglaciation and its contribution to meltwater pulse 1a: Constraining ice sheet history with geomorphological mapping and 10Be exposure dating on Svalbard's southern cape</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nothaft, D. B.; Koffman, T.; Schaefer, J. M.; Young, N. E.; Hormes, A.; Briner, J. P.</p> <p>2014-12-01</p> <p>Pinpointing the sources of meltwater pulse (MWP) 1a—the most abrupt period of sea level rise during the last glacial termination—remains one of <span class="hlt">paleoclimatology</span>'s greatest challenges, with implications for the understanding of rapid climate change, isostatic rebound, and past ocean circulation. Here, we present an annotated geomorphological map of a southern region of Svalbard, Norway, that we will use in the interpretation of a soon-to-be published 10Be chronology of this study area where no cosmogenic nuclide exposure data has yet been produced. From this map, we infer historic ice sheet thickness, flow rate, and erosivity. Together, this data will enable us to constrain ice sheet volume change over time in southern Svalbard. The map identifies raised beaches at an altitude of 40 m, indicating an ice sheet thickness of 400-800 m during the Last Glacial Maximum (LGM) when compared to other shoreline data from the region and ice sheet models. We also observed an abundance of glacially smoothed features in valleys, despite an absence of such features at higher elevations. This could suggest a transition from warm-based, erosive ice to cold-based, non-destructive ice with increasing elevation. It is also possible that mountain peaks in this region were not glaciated at LGM. It is important to assess the historic erosivity of an ice sheet because cosmogenic nuclides may be inherited from prior interstadials when the bedrock was deglaciated, if not "reset" by erosion. This can result in erroneously old exposure dates. If this portion of the Svalbard Barents Sea Ice Sheet (SBSIS) did contribute largely to MWP-1a, then we would expect exposure dates from sites differing in elevation by 100 m or more to fall within a 500-year range, centered around 14 ka. Expeditions to collect samples for exposure dating at other field sites in southern Svalbard, scheduled for the coming field season, will help to further inform our understanding of the SBSIS deglaciation and the MWP</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMPP51B2114S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMPP51B2114S"><span id="translatedtitle">Mid-Holocene climate transition in the Arctic: a database of multicentennial quality climate proxy data from 6 to 2 ka</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sundqvist, H. S.; Kaufman, D. S.; Balascio, N. L.</p> <p>2012-12-01</p> <p>A major goal of <span class="hlt">paleoclimatology</span> is to reconstruct the spatial-temporal pattern of past climate changes. The spatial-temporal pattern of temperature variability reflects the dynamics of the climate system, including its response to known climate forcing mechanisms and thresholds that lead to rapid transitions. A large network of well-dated proxy climate records is needed to capture the details of past climate variability. We have embarked on major systematic compilation of previously published Holocene proxy climate records from the Arctic. The focus is on well-dated, highly resolved, continuous records that extend to at least 6 ka BP, thereby capturing the transition between the relatively warm conditions of the Holocene thermal maximum and the cooler Neoglaciation. We have identified 139 sites from north of 58° latitude where published proxy records are resolved at centennial scale (at least one value every 400 ± 200 years) and have timescales constrained by at least one radiometric age every 3000 years. We have assembled the metadata for the proxy records from all sites including information on their location, archive and proxy types, climate interpretation, quality of the record (sample resolution and geochronological control), and the data source. The database currently (August 2012) includes the numerical proxy records from most of the sites. We have also compiled the original geochronological data, with the future goal of revising the underlying age models and quantifying age uncertainties. The majority (73%) of the proxy records in the current metadatabase are from lake sediments, with the reminder from marine sediment (17%) and glacier ice (7%). Most of the paleo-temperature records (54%) are based on pollen spectra, and another 26% are based on chironomid assemblages. Many of the proxy records reflect changes in precipitation or hydrology (26%). A high proportion of the sites (35%) are from Fennoscandia, 22% are from the Canadian islands and Greenland</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.U13C0064W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.U13C0064W"><span id="translatedtitle">SEARCH: Study of Environmental Arctic Change--A System-scale, Cross-disciplinary, Long-term Arctic Research Program</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wiggins, H. V.; Schlosser, P.; Loring, A. J.; Warnick, W. K.; Committee, S. S.</p> <p>2008-12-01</p> <p>The Study of Environmental Arctic Change (SEARCH) is a multi-agency effort to observe, understand, and guide responses to changes in the arctic system. Interrelated environmental changes in the Arctic are affecting ecosystems and living resources and are impacting local and global communities and economic activities. Under the SEARCH program, guided by the Science Steering Committee (SSC), the Interagency Program Management Committee (IPMC), and the Observing, Understanding, and Responding to Change panels, scientists with a variety of expertise--atmosphere, ocean and sea ice, hydrology and cryosphere, terrestrial ecosystems, human dimensions, and <span class="hlt">paleoclimatology</span>--work together to achieve goals of the program. Over 150 projects and activities contribute to SEARCH implementation. The Observing Change component is underway through National Science Foundation's (NSF) Arctic Observing Network (AON), NOAA-sponsored atmospheric and sea ice observations, and other relevant national and international efforts, including the EU- sponsored Developing Arctic Modelling and Observing Capabilities for Long-term Environmental Studies (DAMOCLES) Program. The Understanding Change component of SEARCH consists of modeling and analysis efforts, with strong linkages to relevant programs such as NSF's Arctic System Synthesis (ARCSS) Program. The Responding to Change element is driven by stakeholder research and applications addressing social and economic concerns. As a national program under the International Study of Arctic Change (ISAC), SEARCH is also working to expand international connections in an effort to better understand the global arctic system. SEARCH is sponsored by eight (8) U.S. agencies, including: the National Science Foundation (NSF), the National Oceanic and Atmospheric Administration (NOAA), the National Aeronautics and Space Administration (NASA), the Department of Defense (DOD), the Department of Energy (DOE), the Department of the Interior (DOI), the Smithsonian</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMPP11D..07U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMPP11D..07U"><span id="translatedtitle">Did tropical rainforest vegetation exist during the Late Cretaceous? New data from the late Campanian to early Maastrichtian Olmos Formation, Coahuila, Mexico.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Upchurch, G. R.; Estrada-Ruiz, E.; Cevallos-Ferriz, S. S.</p> <p>2008-12-01</p> <p>A major problem in paleobotany and <span class="hlt">paleoclimatology</span> is the origin of modern tropical and paratropical rainforests. Studies of leaf macrofossils, beginning with those of Wolfe and Upchurch, have suggested that tropical and paratropical (i.e., megathermal) rainforests with dominant angiosperms are of Cenozoic origin, and that comparable vegetation was either absent or greatly restricted during the Late Cretaceous. Earth System modeling studies, in contrast, predict the existence of megathermal rainforest vegetation during the mid- and Late Cretaceous, though with less areal extent than during the Late Cenozoic and Recent. Megathermal climate with year-round precipitation is simulated along the paleoequator and along the northern margin of the Tethys Ocean, and tends to occur in highly focused regions, in contrast to the more latitudinally zoned pattern of the Recent. Low-resolution climatic indicators, such as the distribution of coals and tree fern spores, are consistent with evidence from climate modeling for megathermal wet climates during the Late Cretaceous, and by extension megathermal rainforest vegetation. However, corroborative data from plant macrofossil assemblages is needed, because the physiognomy of leaves and woods directly reflects plant adaptation to the environment and can estimate climate independently of the generic and familial affinities of the paleoflora. Newly collected plant macrofossil assemblages from the late Campian to early Maastrichtian Olmos Formation of Coahuila, Mexico, provide evidence for megathermal rainforest vegetation on the northern margin of the Tethys Ocean at approximately 35 degrees paleolatitude. The newly collected leaf flora is 72 percent entire- margined and has abundant palms, features typical of modern megathermal rainforests. Thirty percent of the species have large leaves, and 50 percent of the species have drip tips, features indicative of wet conditions. Simple and multiple regression functions based on the</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMPP51A1602T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMPP51A1602T"><span id="translatedtitle">Novel Method for Estimating Variations in Salinity and River Discharge in the Hudson Estuary Using Stable Isotopes of Leaf Waxes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tabanpour, B.; Nichols, J. E.; Isles, P. D.; Peteet, D. M.</p> <p>2010-12-01</p> <p>Understanding variations in the hydrological cycle of the Hudson Valley has important implications for water resources management, affecting millions of New Yorkers. <span class="hlt">Paleoclimatological</span> records of hydrological variability from this region, however, are sparse, as the typical enivronments used for paleohydrological reconstruction do not exist. However, salt marshes are common features of the Hudson River, where the influence of tides is felt far upstream. To take advantage of these environments as recorders of paleohydrology, we present a new method for estimating annual river discharge using salt marsh sediments. We will be examining hydrogen isotopes of leaf waxes in vascular plants to estimate salinity, which will be calibrated to Hudson River discharge using United States Geological Survey (USGS) streamflow data. Freshwater flux from the Hudson Valley is proportional to the salinity at a particular location in the estuary. We estimate the relationship between the salinity and δD using a two-part mixing model where the salinity and δD of ocean water is 35 ppt and 0‰ VSMOW respectively, and the salinity and δD of continental water is 0 ppt and -55‰ (approximately annual average precipitation in the region). It has been shown that the δD of the leaf waxes of aquatic vegetation accurately reflect the δD of growth water. For our experiment, we collected common members of the generaTypha, Spartina, Phragmites, and Scirpus from salt marshes along the Hudson River, and the north and south shores of Long Island to calibrate the specific relationship between marsh plant leaf wax δD and marsh water δD. We compare the measured δD of these plant waxes to the δD of marsh water estimated from salinity measurements made at USGS gage stations near each collection location. We then used the new calibration to estimate late Holocene variations in marsh salinity and thus Hudson River discharge using fossil leaf waxes. This novel method will help us better understand</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMPP41C1778K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMPP41C1778K"><span id="translatedtitle">Limitations When Using Proxies of Atmospheric Circulation to Infer Regional Temperature</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kelsey, E. P.; Wake, C. P.; Osterberg, E. C.; Kreutz, K. J.</p> <p>2011-12-01</p> <p>One objective of ice core <span class="hlt">paleoclimatology</span> is to reconstruct past variability of climate parameters such as surface air temperature. Stable isotope ratios of ice cores collected from some locations can be used with confidence to reconstruct regional air temperature. Other glaciochemical records (e.g., major ions) have been used as proxies for regional atmospheric circulation patterns, including the Arctic Oscillation and Pacific-North American pattern, typically based on the strength of semi-permanent sea level pressure centers such as the Icelandic Low and Aleutian Low. The Arctic Oscillation and Pacific North American pattern are associated with regional air temperature anomalies, and consequently ice core proxies of these circulation patterns could be used to infer paleotemperature patterns. However, detailed analysis of the 20th Century Reanalysis dataset (1871-2008) for the Northern Hemisphere winter suggests that these atmospheric circulation patterns do not always result in the same regional air temperature anomalies. A principal component analysis of detrended and area-weighted winter (December-March) temperature and sea level pressure was performed, and the leading eigenmodes were compared, along with the winter mean positions of the Icelandic and Aleutian Lows. Robust results based on multiple statistical analyses were obtained only when the extreme seasonal values of these variables were examined. Although statistically significant results were obtained when looking at temperature patterns associated with specific sea level pressure patterns and the positions of the Icelandic and Aleutian Lows, more consistent relationships were found when examining sea level pressure patterns associated with the leading eigenmodes of temperature. The seasons of extreme eigenvalues of the leading temperature eigenmodes are associated with mean positions of the Icelandic and Aleutian Lows at climatologically extreme north/south and west/east locations, respectively</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011AGUFMED11A0766M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011AGUFMED11A0766M&link_type=ABSTRACT"><span id="translatedtitle">Dartmouth College Earth Sciences Mobile Field Program</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meyer, E. E.; Osterberg, E. C.; Dade, W. B.; Sonder, L. J.; Renshaw, C. E.; Kelly, M. A.; Hawley, R. L.; Chipman, J. W.; Mikucki, J.; Posmentier, E. S.; Moore, J. R.</p> <p>2011-12-01</p> <p> spend several weeks conducting traditional multiday mapping of complexly-deformed sedimentary, metamorphic and igneous rocks, and also collect and interpret geobiological, geochemical, geophysical, <span class="hlt">paleoclimatological</span>, paleontological, and remote-sensing data outside the context of traditional mapping. During the Mono Lake segment, for example, students examine the interaction of ecology and chemistry in alkaline lakes. During the Canadian Rockies segment, students reconstruct Holocene paleoclimate using tree stumps and fossil wood detritus marking former positions of an alpine glacier. While a mobile, wide-ranging field program requires complicated logistics and potentially high per-student costs, the diversity of research topics, geological environments, and field techniques have made it a successful cornerstone of the Dartmouth Earth Sciences major. After the Stretch experience, significant fractions of our students become involved in ongoing faculty research, pursue senior theses, and go on to pursue Earth Sciences graduate degrees.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMPP21C..06D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMPP21C..06D"><span id="translatedtitle">Geochemically tracking provenance changes in marine sediment from the South Pacific Gyre throughout the Cenozoic</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dunlea, A. G.; Murray, R. W.; Sauvage, J.; Spivack, A. J.; Harris, R. N.; D'Hondt, S. L.</p> <p>2012-12-01</p> <p>The South Pacific Gyre (SPG), characterized by extremely slow sedimentation rates, is the world's largest oceanic desert. The little eolian dust from continents in the Southern Hemisphere must traverse great distances to reach the SPG, and the ultra-oligotrophic waters minimize the biogenic flux of sediment to the seafloor. However sparse, the pelagic sediment that is ultimately found on the seafloor retains a chemical record that can be used to trace its origin. Using cores from Integrated Ocean Drilling Program Expedition 329, we trace downcore fluctuations in major, trace, and rare earth element (REE) composition and flux to yield clues to the geological, chemical, and biological evolution of the SPG throughout the Cenozoic. The shipboard scientific party generally described the completely oxic, brown pelagic clays recovered during Exp. 329 as zeolitic metalliferous clay. The homogenous, very fine-grained nature of these sediments speaks to the challenges we face in resolving eolian detrital material ("dust"), fine-grained ash (commonly altered), and authigenic aluminosilicates from one another. Based on ICP-ES and ICP-MS analyses followed by multivariate statistical treatments, we are developing chemical records from a number of sites located throughout the SPG. Building on earlier work at DSDP Site 596 (Zhou and Kyte, 1992, Paleocean., 7, 441-465), and based on backtrack paths from 100 Ma forward, we are working to construct a regionally and temporally continuous <span class="hlt">paleoclimatological</span> history of the SPG. Preliminary La-Th-Sc concentrations from Sites U1367, U1368, and U1369 show a distinct authigenic influence, but several refractory elements retain their original provenance signature. Sediment ages are constrained using a constant-Co model, based on the geochemically similar work that Zhou and Kyte (1992) performed in the SPG. REE concentrations normalized to post-archean average shale (PAAS) reveal a negative Ce anomaly that becomes more pronounced closer to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.3090L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.3090L"><span id="translatedtitle">Application of the authigenic 10Be/9Be dating method to continental sediments: reconstruction of the Mio-Pleistocene sedimentary sequence in the early hominid fossiliferous areas of the northern Chad Basin.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lebatard, Anne-Elisabeth; Bourlès, Didier L.; Arnold, Maurice; Duringer, Philippe; Schuster, Mathieu; Jolivet, Marc; Braucher, Régis; Taisso Mackaye, Hassan; Vignaud, Patrick; Brunet, Michel</p> <p>2010-05-01</p> <p> deposits from 1 to 8 Ma. The half-life of 10Be theoretically allowing dating up to 14 Ma, it may have fundamental implications on important field research such as <span class="hlt">paleoclimatology</span> and, through the dating of fossiliferous deposits in paleontology and paleoanthropology. Similar studies conducted in different continental context may in addition provide valuable information on the influence of environmental parameters on the biogeochemical behavior of the beryllium isotopes. Acknowledgments: This research was supported by: Chad Minist. Enseign. Sup. et Rech. (N'Djamena Univ. & CNAR); French Minist. Aff. Etrang. (Ambassade de France N'Djamena ; DCSUR, Paris) & Minist. Educ. Natl. et Rech. (CNRS, ECLIPSE, ANR, Univ. of Poitiers); NSF/RHOI. MPFT members are thanked for their supports.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1715569S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1715569S"><span id="translatedtitle">Graduate training in Earth science across borders and disciplines: ArcTrain -"Processes and impacts of climate change in the North Atlantic Ocean and the Canadian Arctic"</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stein, Rüdiger; Kucera, Michal; Walter, Maren; de Vernal, Anne</p> <p>2015-04-01</p> <p>Due to a complex set of feedback processes collectively known as "polar amplification", the Arctic realm is expected to experience a greater-than-average response to global climate forcing. The cascades of feedback processes that connect the Arctic cryosphere, ocean and atmosphere remain incompletely constrained by observations and theory and are difficult to simulate in climate models. Our capacity to predict the future of the region and assess the impacts of Arctic change processes on global and regional environments hinges on the availability of interdisciplinary experts with strong international experience and understanding of the science/society interface. This is the basis of the International Research Training Group "Processes and impacts of climate change in the North Atlantic Ocean and the Canadian Arctic - ArcTrain", which was initiated in 2013. ArcTrain aims to educate PhD students in an interdisciplinary environment that combines <span class="hlt">paleoclimatology</span>, physical oceanography, remote sensing and glaciology with comprehensive Earth system modelling, including sea-ice and ice-sheet components. The qualification program for the PhD students includes joint supervision, mandatory research residences at partner institutions, field courses on land and on sea (Floating University), annual meetings and training workshops and a challenging structured training in expert skills and transferrable skills. Its aim is to enhance the career prospects and employability of the graduates in a challenging international job market across academic and applied sectors. ArcTrain is a collaborative project at the University of Bremen and the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven. The German part of the project is designed to continue for nine years and educate three cohorts of twelve PhD students each. The Canadian partners comprise a consortium of eight universities led by the GEOTOP cluster at the Université du Québec à Montréal and including</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1712930A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1712930A"><span id="translatedtitle">Timing of maximum glacial extent and deglaciation from HualcaHualca volcano (southern Peru), obtained with cosmogenic 36Cl.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alcalá, Jesus; Palacios, David; Vazquez, Lorenzo; Juan Zamorano, Jose</p> <p>2015-04-01</p> <p>Andean glacial deposits are key records of climate fluctuations in the southern hemisphere. During the last decades, in situ cosmogenic nuclides have provided fresh and significant dates to determine past glacier behavior in this region. But still there are many important discrepancies such as the impact of Last Glacial Maximum or the influence of Late Glacial climatic events on glacial mass balances. Furthermore, glacial chronologies from many sites are still missing, such as HualcaHualca (15° 43' S; 71° 52' W; 6,025 masl), a high volcano of the Peruvian Andes located 70 km northwest of Arequipa. The goal of this study is to establish the age of the Maximum Glacier Extent (MGE) and deglaciation at HualcaHualca volcano. To achieve this objetive, we focused in four valleys (Huayuray, Pujro Huayjo, Mollebaya and Mucurca) characterized by a well-preserved sequence of moraines and roches moutonnées. The method is based on geomorphological analysis supported by cosmogenic 36Cl surface exposure dating. 36Cl ages have been estimated with the CHLOE calculator and were compared with other central Andean glacial chronologies as well as <span class="hlt">paleoclimatological</span> proxies. In Huayuray valley, exposure ages indicates that MGE occurred ~ 18 - 16 ka. Later, the ice mass gradually retreated but this process was interrupted by at least two readvances; the last one has been dated at ~ 12 ka. In the other hand, 36Cl result reflects a MGE age of ~ 13 ka in Mollebaya valley. Also, two samples obtained in Pujro-Huayjo and Mucurca valleys associated with MGE have an exposure age of 10-9 ka, but likely are moraine boulders affected by exhumation or erosion processes. Deglaciation in HualcaHualca volcano began abruptly ~ 11.5 ka ago according to a 36Cl age from a polished and striated bedrock in Pujro Huayjo valley, presumably as a result of reduced precipitation as well as a global increase of temperatures. The glacier evolution at HualcaHualca volcano presents a high correlation with</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMPP41C1373C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMPP41C1373C"><span id="translatedtitle">Climcor: Paleoclimatic Coring: High Resolution and Innovations.Cnrs Gathers the Present Coring Equipment , and Coordinates the Different Efforts Provided By the Concerned Communities (ocean, ice and continent)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Calzas, M.; Rousseau, D. D.</p> <p>2014-12-01</p> <p>Global climate changes have been evidenced in various ways since the start of <span class="hlt">paleoclimatology</span> in the 70s. The access to past atmosphere conditions in the air bubbles trapped in ice-cores gave an important impulse as it made the green-house gases concentrations accessible a prerequisite for climate modelers. Indeed since the publication of CO2 and CH4 variations over the last climate cycle in Vostok ice-cores, our knowledge of the past climate conditions has improved tremendously. However, improvements in technical equipment and approaches indicate that more is still to come inducing expected new findings in terms of mechanisms. The IMAGES program yielded very good quality and long marine cores that permitted to compare marine and ice-core records with high confidence. Moreover they permitted to improve the knowledge of past oceans dynamics, especially those linked to the massive discharges of icebergs in the oceans, impacting the Atlantic meridional overturning circulation. On the continent, various environments are drilled and cored to provide also comparable and reliable records of past climate: lakes, peatbogs, speleothems and loess. These records are complementary yielding important dataset to feed the earth system models necessary for a better understanding of past climate dynamics. Technical limitation of the present equipments does not allow such important jump in the quality of the data, and therefore in the knowledge of i, past climate variations at extremely high resolution and ii, of the behavior of the different domains as studied in IPCC experiments while societal requirements are more and more expressed by policy makers. C2FN initiative at CNRS gathers the present coring equipments located in labs or at the technical division of INSU, and coordinates the different efforts provided by the concerned communities (ocean, ice and continent). Valorization of the results obtained are published in high ranked scientific journals and presented in scientific</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFMED23E..02S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFMED23E..02S&link_type=ABSTRACT"><span id="translatedtitle">Development and sustainability of NSF-funded climate change education efforts: lessons learned and strategies used to develop the Reconstructing Earth's Climate History (REaCH) curriculum (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>St John, K. K.; Jones, M. H.; Leckie, R. M.; Pound, K. S.; Krissek, L. A.</p> <p>2013-12-01</p> <p> develop detailed instructor guides to accompany each module. After careful consideration of dissemination options, we choose to publish the full suite of exercise modules as a commercially-available book, Reconstructing Earth's Climate History, while also providing open online access to a subset of modules. Its current use in undergraduate <span class="hlt">paleoclimatology</span> courses, and the availability of select modules for use in other courses demonstrate that creative, hybrid options can be found for lasting dissemination, and thus sustainability. In achieving our goal of making science accessible, we believe we have followed a curriculum development process and sustainability path that can be used by others to meet needs in earth, ocean, and atmospheric science education. Next steps for REaCH include exploration of its use in blended learning classrooms, and at minority serving institutions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMPP23A1365V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMPP23A1365V"><span id="translatedtitle">Driftwood dropstones in mid-Miocene shallow marine strata (Calvert Cliffs, Maryland Coastal Plain): An erratic lithic pebble des not necessarily a cold paleoclimate make</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vogt, P. R.; Parrish, M.</p> <p>2009-12-01</p> <p>Erratic lithic pebbles recovered from marine sediments are routinely identified as Ice-Rafted Debris (IRD), transported by icebergs, sea ice, or river ice discharged into the sea. We suggest this is not always the transport mechanism--especially when other <span class="hlt">paleoclimatologic</span> proxies indicate relatively warm climates and extensive forests in the pebble provenance regions. Rivers could transport significant amounts of pebbbles as driftwood dropstones, trapped in the roots of trees and later uprooted in floods and carried out to sea. To illustrate a likely example of Tree-Rafted Detritus (TRD), we analyzed a collection of lithic erratics collected from three beds in eroding (5-10 cm/a) mid-Miocene (Serravalian)shallow marine deposits (upper Calvert Formation,Chesapeake Bay, southern Maryland), which predate the ca. 13.9 Ma global cooling and expansion of the East Antarctic Ice Sheet. The ca. 220 specimens (1-10 cm in diameter) are extremely variable in lithology and degree of roundness. The great majority are evidently of Piedmont provenance and were probably rafted ca. 120 km to the collection site from the paleo-mouth of the Susquehanna River, floated out to sea and carried south by the Miocene Coastal Current. River ice can probably be ruled out as the transport mechanism, given the prevailing warm temperate to subtropical climates. Common carbonized wood fragments (typically 2 x 10 cm in outcrop dimensions) in the same strata containing the erratics support driftwood transport. The lithic erratics may serve as independent tracers for terrestrial vertebrate fossils, transported into the Calvert Sea (Atlantic Ocean) by the 'float and bloat' mechanism.(Allowance has to be made for ca. 20 m/Ma post-middle Miocene source region denudation). However,only 3% of the clasts (mostly quartz diorite gneiss)could be readily related to a specific outcrop--the Port Deposit Gneiss near the modern mouth of the Susquehanna River. We suggest that driftwood transport be considered as</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUSMGC53A..01F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUSMGC53A..01F"><span id="translatedtitle">Differential Responses of Neotropical Mountain Forests to Climate Change during the Last Millenium</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Figueroa-Rangel, B. L.; Olvera Vargas, M.</p> <p>2013-05-01</p> <p>The long-term perspective in the conservation of mountain ecosystems using palaeoecological and <span class="hlt">paleoclimatological</span> techniques are providing with crucial information for the understanding of the temporal range and variability of ecological pattern and processes. This perception is contributing with means to anticipate future conditions of these ecosystems, especially their response to climate change. Neotropical mountain forests, created by a particular geological and climatic history in the Americas, represent one of the most distinctive ecosystems in the tropics which are constantly subject to disturbances included climate change. Mexico due to its geographical location between the convergence of temperate and tropical elements, its diverse physiography and climatic heterogeneity, contains neotropical ecosystems with high biodiversity and endemicity whose structure and taxonomical composition have changed along centurial to millennial scales. Different neotropical forests expand along the mountain chains of Mexico with particular responses along spatial and temporal scales. Therefore in order to capture these scales at fine resolution, sedimentary sequences from forest hollows were retrieved from three forest at different altitudes within 10 km; Pine forest (PF), Transitional forest (TF) and Cloud forest (CF). Ordination techniques were used to relate changes in vegetation with the environment every ~60 years. The three forests experience the effect of the dry stage ~AD 800-1200 related to the Medieval Warm Period reported for several regions of the world. CF contracted, PF expanded while the TF evolved from CF to a community dominated by dry-resistant epiphytes. Dry periods in PF and TF overlapped with the increase in fire occurrences while a dissimilar pattern took place in CF. Maize, Asteraceae and Poaceae were higher during dry intervals while epiphytes decreased. A humid period ~1200-1450 AD was associated with an expansion and a high taxa turnover in CF</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.P44A..07V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.P44A..07V"><span id="translatedtitle">Sulfate Hydration States in Interpretation of Martian Mineral Assemblages</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vaniman, D. T.; Bish, D. L.</p> <p>2008-12-01</p> <p> associations on Mars provide mineral tools to interpret depositional origins, paleohydrology, and <span class="hlt">paleoclimatology</span>, but these tools require attention to environments of formation, stability relations, and kinetics of hydration and dehydration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFMPP62A0331L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFMPP62A0331L"><span id="translatedtitle">A Multi-proxy Approach to Distinguish Between Changes in SST and Meltwater Input in the Gulf of Mexico Back to MIS 3.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lodico, J. M.; Hastings, D. W.; Flower, B. P.; Quinn, T. M.</p> <p>2002-12-01</p> <p>The Gulf of Mexico (GOM) is part of the Western Hemisphere Warm Pool providing a source of heat and moisture to the North American continent and Northern high latitudes. Paleoclimatic records from the GOM can test the hypothesis that the tropical climate system is an important driver of past global climate change. In July 2002, core MD02-2551 was taken by the French research vessel Marion Dufresne at 26°56.78 N 91°21.75 W and recovered 31.79 m of sediment from Orca Basin situated in the northern GOM 290 km south of the present Louisiana coast. The basin is advantageous for high-resolution <span class="hlt">paleoclimatology</span> because of a brine layer overlying the sediment that preserves sedimentary laminations and high sedimentation rates estimated at greater than 50 cm/1000 yr. A multi-proxy approach using Mg/Ca and δ18O from foraminiferal calcite will isolate past sea surface temperature (SST) and δ18O of sea water (controlled by salinity, and ice volume). Separation of these parameters will help establish the relationship between changing GOM SSTs and meltwater input from the Laurentide Ice Sheet. The chronology of the core is being established using AMS C14 dating. Both white and pink species of the planktonic foraminifera Globigerinoides ruber were analyzed for δ18O and will be analyzed for Mg/Ca. Coarse resolution data from white G. ruber show a mean value of about -1.5 per mil during the Holocene (low variability of <0.5 per mil) and a mean value of about 0.0 per mil at the Last Glacial Maximum (low variability of <0.5 per mil). Marine Isotope Stage Three (MIS 3) indicates a mean value of about -0.75 per mil (high variability of >0.5 per mil). Sea surface temperature and sea surface salinity have distinctly higher variability during MIS 3 in comparison to the Holocene. Foraminiferal Mg data will add an additional constraint for SST. Phasing between GOM SSTs and high latitude temperatures will help assess the role of the tropical climate system on global climate change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMED33A0934R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMED33A0934R&link_type=ABSTRACT"><span id="translatedtitle">Climate Literacy: STEM and Climate Change Education and Remote Sensing Applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reddy, S. R.</p> <p>2015-12-01</p> <p>NASA Innovations in Climate Education (NICE) is a competitive project to promote climate and Earth system science literacy and seeks to increase the access of underrepresented minority groups to science careers and educational opportunities. A three year funding was received from NASA to partnership with JSU and MSU under cooperative agreement "Strengthening Global Climate Change education through Remote Sensing Application in Coastal Environment using NASA Satellite Data and Models". The goal is to increase the number of highschool and undergraduate students at Jackson State University, a Historically Black University, who are prepared to pursue higher academic degrees and careers in STEM fields. A five Saturday course/workshop was held during March/April 2015 at JSU, focusing on historical and technical concepts of math, enginneering, technology and atmosphere and climate change and remote sensing technology and applications to weather and climate. Nine students from meteorology, biology, industrial technology and computer science/engineering of JSU and 19 high scool students from Jackson Public Schools participated in the course/workshop. The lecture topics include: introduction to remote sensing and GIS, introduction to atmospheric science, math and engineering, climate, introduction to NASA innovations in climate education, introduction to remote sensing technology for bio-geosphere, introduction to earth system science, principles of <span class="hlt">paleoclimatology</span> and global change, daily weather briefing, satellite image interpretation and so on. In addition to lectures, lab sessions were held for hand-on experiences for remote sensing applications to atmosphere, biosphere, earth system science and climate change using ERDAS/ENVI GIS software and satellite tools. Field trip to Barnett reservoir and National weather Service (NWS) was part of the workshop. Basics of Earth System Science is a non-mathematical introductory course designed for high school seniors, high school</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFMED23B3486R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFMED23B3486R&link_type=ABSTRACT"><span id="translatedtitle">NASA Partnership with JSU and MSU to Promote Remote Sensing Applications and Global Climate Change Education: 2013 Summer Course/Workshop</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reddy, S. R.</p> <p>2014-12-01</p> <p>NASA Innovations in Climate Education (NICE) is a competitive project to promote climate and Earth system science literacy and seeks to increase the access of underrepresented minority groups to science careers and educational opportunities. A three year funding was received from NASA to partnership with JSU and MSU under cooperative agreement "Strengthening Global Climate Change education through Remote Sensing Application in Coastal Environment using NASA Satellite Data and Models". The goal is to increase the number of undergraduate students at Jackson State University, a Historically Black University, who are prepared to pursue higher academic degrees and careers in the fields relevant to earth system science global climate change, marine and environmental sciences. A two week summer course/workshop was held during May 20-31, 2013 at JSU, focusing on historical and technical concepts of remote sensing technology and applications to climate and global climate change. Nine students from meteorology, biology, industrial technology and computer science/engineering of JSU participated in the course/workshop. The lecture topics include: introduction to remote sensing and GIS, introduction to atmospheric science and climate, introduction to NASA innovations in climate education, introduction to remote sensing technology for bio-geosphere, introduction to earth system science, principles of <span class="hlt">paleoclimatology</span> and global change, daily weather briefing, satellite image interpretation and so on. In addition to lectures, lab sessions were held for hand-on experiences for remote sensing applications to atmosphere, biosphere, earth system science and climate change using ERDAS/ENVI GIS software and satellite tools. Field trip to Barnett reservoir and National weather Service (NWS) was part of the workshop. Some of the activities of the sessions will be presented. Basics of Earth System Science is a non-mathematical introductory course designed for high school seniors, high</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010GPC....72..321B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010GPC....72..321B"><span id="translatedtitle">Lake Malawi sediment and pore water chemistry: Proposition of a conceptual model for stratification intensification since the end of the Little Ice Age</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Branchu, Philippe; Bergonzini, Laurent; Pons-branchu, Edwige; Violier, Eric; Dittrich, Maria; Massault, Marc; Ghaleb, Bassam</p> <p>2010-07-01</p> <p>Sedimentary records of salinity indicators are largely used to reconstruct past climatic changes in lacustrine systems where chemistry is sensitive to hydroclimatic conditions. In large fresh lakes of the East African Rift such as Lakes Tanganyika and Malawi, salinity is often considered constant and other <span class="hlt">paleoclimatological</span> proxy data are used. However, a relation between lake surface chloride concentration and hydroclimatic regime was previously demonstrated at the century scale in Lake Tanganyika. This relation is transposed to Lake Malawi on the base of similarity between hydrochemical budgets of both lakes that are computed for the whole lake and epilimnion. Whereas numerous physico-chemical difficulties make generally debatable use of lake pore water chemistry, as illustrated here by diffusion modelling, the dissolved chloride concentration profile from a core sampled in northern Lake Malawi is considered as a potential indicator of limnological-hydroclimatic condition changes for the last 200 years. A decrease in pore water chloride concentration between 1840 AD and present situation is directly associated to a metalimnetic water salinity decrease. The chronology of this event is synchronous with diatom productivity change demonstrated by Johnson et al. (2001) at the end of the Little Ice Age (LIA). A conceptual model of Lake Malawi, based on salinity, organic carbon and its "dead" watershed contribution, lake-level and productivity changes since the mid 19th century is presented. A new scenario is proposed, based on thermal stratification reinforcement at the end of the LIA. Lake productivity and chemistry depend on stratification strength, water column mixing rate and on climatic variability. During the LIA, nutrient distribution profiles were more homogeneous with depth due to the climatically (colder and drier climatic conditions than today) induced destabilisation of the mixing barrier. The productive system is then auto-supplied and does not require</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMEP11A..06L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMEP11A..06L"><span id="translatedtitle">Sedimentary dynamic processes of a contourite drift formation in the South China Sea: from long-term in situ observations to geological records</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Z.; Zhao, Y.; Zhang, Y.; Li, J.; Wen, K.; Li, X.; Tuo, S.; Zhong, G.</p> <p>2015-12-01</p> <p>Contourites are sediments deposited or substantially reworked by thermohaline-induced deepwater bottom currents. The study of contourites with growing interests is widely conducted in seismic stratigraphy, paleoceanography, <span class="hlt">paleoclimatology</span>, and hydrocarbon exploration. However, the sedimentary dynamic process producing contourites in the deepwater environment is still poorly understood. This research presents an interdisciplinary approach from long-term in situ mooring and tripod observations, multi-beam seabed morphology, seismic stratigraphy, to IMAGES (Marion Dufresne) piston coring and ODP (JOIDES Resolution) drilling studies on the formation of a contourite drift on the lower slope of the northern South China Sea. The contourite drift with ~520 m thick is distributed in water depths ranging from 1650 m to 2500 m and has been accumulated since 1.5 Ma in early Pleistocene. The nowadays contour currents in the northern South China Sea were observed with velocities generally ranging in 0-2 cm/s with a dominant flow direction of ~250º (southwestward/along-slope). However, the relatively stable contour currents were disturbed by several bursts of increased velocities up to 8-11 cm/s, each lasting 2-3 weeks and followed by a direction reversal, which were caused by passing-through of deep-reaching mesoscale eddies. The along-slope sediment transport is induced by both mesoscale eddy and contour currents, and these suspended sediments are mainly derived from Taiwan according to provenance analysis of sediments traps equipped on moorings. Seismic stratigraphy and core sample analysis (oxygen isotope stratigraphy, clay mineralogy, and grain size) reveal a long sedimentary history with strong influence of deepwater currents that have carried the majority of Taiwan-sourced sediments moving westward since early Pleistocene. The glacial-cyclic terrigenous input from various surrounding drainage systems and their transport processes from fluvial source to deep-sea sink are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMPP51E..06K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMPP51E..06K"><span id="translatedtitle">Tephrochronology of Lacustrine Ash Layers in Lake Petén Itzá Sediments drilled in the Frame of the International Continental Scientific Drilling Program (ICDP): Implications for Regional Volcanology and Central American Palaeoclimate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kutterolf, S.; Schindlbeck, J. C.; Anselmetti, F.; Mueller, A.; Schwalb, A.; Eisele, S.; Hemming, S. R.; Wang, K. L.</p> <p>2015-12-01</p> <p>Climate records from lacustrine systems have been established in the last years to improve our understanding of the regional and temporal expression of climate change on the continents, and how it influenced the human evolution. Lake Petén Itzá, located in the center of the climatically sensitive Peninsula Yucatán, is a surficial closed-basin lake located in the lowlands of northern Guatemala drilled by ICDP. The region itself exhibits characteristic climate conditions, making it an ideal region for <span class="hlt">paleoclimatological</span> and paleoecological studies. A key problem in obtaining a long-lasting climate record is to establish robust chronologies beyond 40 ka since they exceed the range of 14C dating, but tephra layers within these sediments may provide good age-constraints >40 ka. We here use large-magnitude, widespread, Pleistocene to Holocene silicic eruptions from caldera volcanoes in the Central American volcanic arc (CAVA), contributing to the drilled Petén Itzá lake sediments in the form of numerous lacustrine tephras providing time markers to develop a new, extended age model. We established robust and well-constrained correlations between the tephras in Lake Petén Itzá and the deposits at the CAVA source as well as their marine equivalents in the sediments of the Pacific Ocean based on major and trace element glass compositions. We document here 8 well-constraint time markers for the Petén Itza age models, which so far were only based on younger 14C dates and some preliminary, only major-element based, tephra correlations. Additionally ongoing Ar/Ar age dating of the Los Chocoyos eruption will provide a new pinning point froma an important regional marker horizon. In summary we have been able to modify the current age models, extend the paleoclimate and paleoecological record in this neotropical region to ~300 ka, and contribute greatly to the determination of the magnitude (eruptive volumes) and more precise eruption dates of CAVA eruptions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS43E1326A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS43E1326A"><span id="translatedtitle">Atlantic Meridional Overturning Circulation during Heinrich-Stadial 1 & 2 as seen by 231Pa/230Th</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Antz, B.; Lippold, J. A.; Schulz, H.; Frank, N.; Mangini, A.</p> <p>2014-12-01</p> <p>Assessing the sensitivity of the Atlantic Meridional Overturning Circulation (AMOC) is a major challenge for <span class="hlt">paleoclimatology</span>, because its strength and structure is a crucial element of the global heat- and carbon distribution towards the deep ocean. Here the focus is set on how excessive freshwater input through abrupt melting of continental ice sheets can affect its overturning vigour. Such forcing can be tested by investigating its behaviour during extreme iceberg discharge events into the open North Atlantic during the last glacial period, so called Heinrich-Events [Heinrich 1988; Hemming 2004]. The sedimentary activity ratio 231Pa/230Th has been increasingly used as a kinematic circulation proxy in the Atlantic Ocean over the past decade [Gherardi et al. 2009; McManus et al. 2004; Lippold et al. 2012]. Here we present 231Pa/230Th ratios from several Atlantic sediment cores across Heinrich Events 1 (~17 ka BP) and 2 (~24 ka BP). The comparison of the profiles demonstrates the potential pitfalls when interpreating a single 231Pa/230Th profile. E. g. core IODP 1313 (Mid Atlantic Ridge, 3412 m water depth) shows 231Pa/230Th between 0.04 and 0.06, which would indicate a vigorous circulation over the entire time period. On the other hand core GeoB 16202-2 (Brasilan coastal area, 2248 m water depth) has a profile similar to the well known data set of [McManus et al. 2004] (i.e. during Heinrich Stadials values close to the production ratio of ~0.093, lower values at Holocene and LGM). Such divergency can be explained by 231Pa/230Th dependence on water depth, latitude, water mass and water mass age [Luo et al. 2010; Lippold et al. 2011], but also on changes in bioproductivity especially the flux of biogenic opal [Anderson et al. 1983A; Bradtmiller et al. 2007; Chase et al. 2002]. To avoid misleading interpretations, the here shown data set is accompanied by measurements of biogenic opal contents to appraise possible influences on the proxies. We observe large</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010BGeo....7..483Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010BGeo....7..483Z"><span id="translatedtitle">Selective preservation of organic matter in marine environments; processes and impact on the sedimentary record</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zonneveld, K. A. F.; Versteegh, G. J. M.; Kasten, S.; Eglinton, T. I.; Emeis, K.-C.; Huguet, C.; Koch, B. P.; de Lange, G. J.; de Leeuw, J. W.; Middelburg, J. J.; Mollenhauer, G.; Prahl, F. G.; Rethemeyer, J.; Wakeham, S. G.</p> <p>2010-02-01</p> <p> accurate reconstruction of past productivity and bottom water oxygenation. Given the cost and effort associated with programs to recover sediment cores for <span class="hlt">paleoclimatological</span> studies, as well as with generating proxy records, it would seem wise to develop a detailed sedimentological and diagenetic context for interpretation of these records. With respect to the latter, parallel acquisition of data that inform on the fidelity of the proxy signatures and reveal potential diagenetic biases would be of clear value.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMPP51E..05M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMPP51E..05M"><span id="translatedtitle">Reconciling radiocarbon and ice core timescales over the Holocene - Cosmogenic radionuclides as synchronization tools</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Muscheler, R.; Adolphi, F.; Mekhaldi, F.</p> <p>2015-12-01</p> <p>The atmospheric production rates of cosmogenic radionuclides, such as 14C and 10Be, vary globally due to external processes, namely the solar and geomagnetic modulation of the galactic cosmic ray flux as well as solar proton events. This signature is recorded in various archives such as ice cores (10Be) and tree-rings (14C). Hence, cosmogenic radionuclides offer a means to continuously assess timescale differences between two of the most widely used timescales in <span class="hlt">paleoclimatology</span> - the radiocarbon and the ice core timescales. Short lived solar proton events additionally provide distinct marker horizons that allow synchronization of discrete horizons at annual precision. We will present a cosmogenic radionuclide based synchronization of the Greenland ice core timescale (GICC05, Svensson et al., 2008) and the radiocarbon timescale (IntCal13, Reimer et al., 2013) over the Holocene. This synchronization allows radiocarbon dated and ice core paleoclimate records to be compared on a common timescale at down to sub-decadal precision. We will compare these results to independent discrete isochrones obtained from tephrochronology and solar proton events. In addition, we will discuss implications for the accuracy and uncertainty estimates of GICC05 over the Holocene. Reimer, P. J., Bard, E., Bayliss, A., Beck, J. W., Blackwell, P. G., Bronk Ramsey, C., Buck, C. E., Cheng, H., Edwards, R. L., Friedrich, M., Grootes, P. M., Guilderson, T. P., Haflidason, H., Hajdas, I., Hatté, C., Heaton, T. J., Hoffmann, D. L., Hogg, A. G., Hughen, K. A., Kaiser, K. F., Kromer, B., Manning, S. W., Niu, M., Reimer, R. W., Richards, D. A., Scott, E. M., Southon, J. R., Staff, R. A., Turney, C. S. M., and van der Plicht, J.: IntCal13 and Marine13 Radiocarbon Age Calibration Curves 0-50,000 Years cal BP, Radiocarbon, 55, 1869-1887, 10.2458/azu_js_rc.55.16947, 2013. Svensson, A., Andersen, K. K., Bigler, M., Clausen, H. B., Dahl-Jensen, D., Davies, S. M., Johnsen, S. J., Muscheler, R., Parrenin</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFMED33A1382R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFMED33A1382R"><span id="translatedtitle">A Demographic Analysis of American Geophysical Union Membership with Implications for Change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rhodes, D. D.</p> <p>2006-12-01</p> <p>Demographers use population pyramids to characterize the age/gender structure of societal groups. Diagrams of the population of age cohorts for both sexes assume the shape of a pyramid in rapidly expanding groups, having many more young people than older adults. Stable populations have similar numbers of people in age cohorts from infants through middle-age adults. Shrinking populations have fewer children and relatively larger numbers of adults. Demographic analysis of the American Geophysical Union's (AGU) membership reveals significant differences among the numerous specialties and the membership as a whole. The population structure diagram of the total AGU membership is highly asymmetrical with 77.5% male and 22.5% female. Males outnumber females in every age cohort. This is most noticeable among members born prior to 1945. Males belonging to these cohorts make up 16.5% of the total membership, while female members of equivalent age include 0.8% of the total. The largest membership cohort (29% of the total) is comprised of males born between 1950 and 1964, a group that includes both the "baby boom" generation and post-war petroleum exploration expansion. In contrast, the female cohort with birth years from 1970 to 1979 is the largest grouping of women members (8.4% of AGU's membership). Furthermore, women comprise 36% of the members born since 1965, and only 14.5% of those born before 1965. Considered separately, the female membership's age structure is characteristic of a growing population, while the male side is in relative decline. The population structure of the entire membership is mirrored in some specialties, but there are remarkable differences in others. The largest specialty group (hydrology) includes 16.9% of the total AGU membership and has a population structure that differs little from that of the whole organization. Four specialties, Atmospheric Chemistry, Biogeosciences, and Paleoceanography and <span class="hlt">Paleoclimatology</span>, and Marine Geochemistry differ</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMGC21D1000K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMGC21D1000K"><span id="translatedtitle">Evolution of Glacier Snowline Since the End of the Last Ice Age in New Zealand</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaplan, M. R.; Putnam, A. E.; Schaefer, J. M.; Denton, G. H.; Chinn, T. J.; Barrell, D.; Doughty, A. M.; Mackintosh, A. N.; Andersen, B. G.</p> <p>2012-12-01</p> <p>An important problem in <span class="hlt">paleoclimatology</span> is how Southern Hemisphere climate changed since the end of the last ice age. The terrestrial glacier record reflects past snowline (=equilibrium line altitude) variability and is one of the few direct proxies available, in the middle latitudes, of former atmospheric properties. We reconstruct changes in snowline since ~15 ka on the South Island of New Zealand using geomorphologic mapping, 10Be surface-exposure dating, accumulation-area ratio (AAR) methods and numerical modeling. The snowline data are a proxy for the 0°C atmospheric isotherm, which occurs above 1500 m asl in the central Southern Alps, and trends in temperature since ~15 ka. Our findings show that snowline was depressed during the Antarctic Cold Reversal. Subsequently, snowline rose ~100 m during the Younger Dryas stadial in Europe. These late glacial changes appear coherent across the southern middle latitudes. In the early Holocene, snowline was depressed >200 m relative to modern in the Southern Alps. Between 11 ka and 600 years ago, short-term oscillations punctuated a multi-millennia trend of decreasing glacier extent as snowline rose ~100 m. Since ~600 yrs ago, net snowline has continued progressively to rise. The record implies long-term warming in New Zealand since the Late Glacial period. During the Holocene, the lowest snowlines and most extensive glaciers occurred in the early part of the epoch. Snowline reconstruction and numerical modeling allow us to estimate that temperature depression during the Late Glacial was ~2.1±0.4°C (relative to modern) and increased about 0.6 to 1°C between the early and late Holocene. Our terrestrial glacier and snowline records show coherence and also they are consistent with marine records in the Australian sector, documenting a regional climate pattern. However, the climate of the southwest Pacific region was fundamentally different from that observed in the Northern Hemisphere, where the most extensive</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PhDT........35H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PhDT........35H&link_type=ABSTRACT"><span id="translatedtitle">Late Quaternary and future biome simulations for Alaska and Eastern Russia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hendricks, Amy S.</p> <p></p> <p>Arctic biomes across a region including Alaska and Eastern Russia were investigated using the BIOME4 biogeochemical and biogeography vegetation model. This study investigated past (the last 21,000 years), present, and future vegetation distributions in the study area, using climate forcing from five CMIP5 models (CCSM4, GISS-E2-R, MIROC-ESM, MPI-ESM, and MRI-CGCM3). The present-day BIOME4 simulations were generally consistent with current vegetation observations in the study region characterized by evergreen and deciduous taiga and shrub tundras. <span class="hlt">Paleoclimatological</span> simulations were compared with pollen data samples collected in the study region. Pre-industrial biome simulations are generally similar to the modern reconstruction but differ by having more shrub tundra in both Russia and Alaska to the north, as well as less deciduous taiga in Alaska. Pre-industrial simulations were in good agreement with the pollen data. Mid-Holocene simulations place shrub tundras along the Arctic coast, and in some cases along the eastern coast of Russia. Simulations for the Mid-Holocene are in good agreement with pollen-based distributions of biomes. Simulations for the Last Glacial Maximum (LGM) show that the Bering Land Bridge was covered almost entirely by cushion forb, lichen and moss tundra, shrub tundra, and graminoid tundra. Three out of the five models' climate data produce evergreen and deciduous taiga in what is now southwestern Alaska, however the pollen data does not support this. The distributions of cushion forb, lichen, and moss tundra and graminoid tundra differ noticeably between models, while shrub tundra distributions are generally similar. Future simulations of BIOME4 based on the RCP8.5 climate scenario indicate a northward shift of the treeline and a significant areal decrease of shrub tundra and graminoid tundra regions in the 21st century. Intrusions of cool mixed, deciduous, and conifer forests above 60°N, especially in southwest Alaska, were notable</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ESRv..116..170S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ESRv..116..170S"><span id="translatedtitle">Bulk composition of northern African dust and its source sediments — A compilation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scheuvens, Dirk; Schütz, Lothar; Kandler, Konrad; Ebert, Martin; Weinbruch, Stephan</p> <p>2013-01-01</p> <p> incorporating the composition of source sediments (e.g., mineralogy) into global or regional dust transport models and can be compared with source analysis by remote sensing or back-trajectory analysis. However, source apportionment studies supported by our data set will not only be useful for actual dust samples, but will also be helpful for the understanding of paleo-wind directions and hence <span class="hlt">paleo-climatological</span> conditions through the investigation of Quaternary eolian sediments deposited in and around northern Africa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMPP43C..08L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMPP43C..08L"><span id="translatedtitle">A New Method of Obtaining High-Resolution Paleoclimate Records from Speleothem Fluid Inclusions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Logan, A. J.; Horton, T. W.</p> <p>2010-12-01</p> <p>We present a new method for stable hydrogen and oxygen isotope analysis of ancient drip water trapped within cave speleothems. Our method improves on existing fluid inclusion isotopic analytical techniques in that it decreases the sample size by a factor of ten or more, dramatically improving the spatial and temporal precision of fluid inclusion-based <span class="hlt">paleoclimatology</span>. Published thermal extraction methods require large samples (c. 150 mg) and temperatures high enough (c. 500-900°C) to cause calcite decomposition, which is also associated with isotopic fractionation of the trapped fluids. Extraction by crushing faces similar challenges, where the failure to extract all the trapped fluid can result in isotopic fractionation, and samples in excess of 500 mg are required. Our new method combines the strengths of these published thermal and crushing methods using continuous-flow isotope ratio analytical techniques. Our method combines relatively low-temperature (~250°C) thermal decrepitation with cryogenic trapping across a switching valve sample loop. In brief, ~20 mg carbonate samples are dried (75°C for >1 hour) and heated (250°C for >1 hour) in a quartz sample chamber under a continuously flowing stream of ultra-high purity helium. Heating of the sample chamber is achieved by use of a tube furnace. Fluids released during the heating step are trapped in a coiled stainless steel cold trap (~ -98°C) serving as the sample loop in a 6-way switching valve. Trapped fluids are subsequently injected into a high-temperature conversion elemental analyzer by switching the valve and rapidly thawing the trap. This approach yielded accurate and precise measurements of injected liquid water IAEA reference materials (GISP; SMOW2; SLAP2) for both hydrogen and oxygen isotopic compositions. Blanking tests performed on the extraction line demonstrate extremely low line-blank peak heights (<50mv). Our tests also demonstrate that complete recovery of liquid water is possible and that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013EGUGA..15..768Y&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013EGUGA..15..768Y&link_type=ABSTRACT"><span id="translatedtitle">Reconciling late Quaternary transgressions in the Bohai Sea, China to the global sea level changes, and new linkage of sedimentary records to three astronomical rhythms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yi, Liang</p> <p>2013-04-01</p> <p>The Bohai Sea in China was formed by subsidence during the Cenozoic. Some 2000-3000 m of fluvial, lacustrine and marine sediments has been deposited in the basin (IOCAS 1985), and these sediments have great potentials in high-/low-latitude interaction, environmental impacts on ancient human activities, and other important issues (Liu, 2009; Yi et al. 2012a), because it is influenced by the Siberian-Mongolian Highs and the ITCZ, and is close to the Nihewan basin and the Zhoukoudian site which are both world-renowned for the discovery of Homo erectus. Since the 1970s, hundreds of studies have been conducted around the Bohai Sea and the major results could be summarized as follows (Zhao et al., 1978; IOCAS, 1985; Liu, 2009, and references therein): (1) constrained by radiocarbon dating, TL/OSL or geomagnetic excursion, three transgressions (T1, T2, T3) developed during the Holocene, marine isotopic stage (MIS) 3 and MIS 5, respectively; and (2) regressions occurred at the beginning of glacial stages, i.e. MIS2 and MIS4. However, apparent inconsistency could be found between T2 and T3, and the question is that in the context that MIS 3 is an inter-stadial stage with a global sea level of 60~80 m lower than the present (Chappell et al. 1996), how did T2 occur in the Bohai Sea, and why did T2 have much larger influence than T3 which occurred at the beginning of MIS 5? To correlate regional environmental changes with global pattern and thus to detect the potential interaction between various driving factors on orbital timescales, three cores with a high recovery rate were drilled in the south Bohai Sea. This study was conducted following three perspectives: chronology (Yi et al. 2012b), sea-level change (Yi et al. 2012c) and <span class="hlt">paleoclimatology</span> (Yi et al. 2012a), and the main results are as follows: 1. Chronology. Luminescence and radiocarbon dating methods were applied in dating these coastal/marine sediments: (1) For Holocene samples, most of the radiocarbon dates agree</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1213224B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1213224B"><span id="translatedtitle">Comparison of climate proxies from two 'Siamese twin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Belén Muñoz-García, María.; Rossi, Carlos; Jesús Turrero, María.; Martín-Chivelet, Javier</p> <p>2010-05-01</p> <p> of 281 samples drilled along the growth axes of both stalagmites. According to the proposed age model, the two stalagmites grew at very different rates, despite their proximity and their internal and external resemblance. The differences are very important in both magnitude and trends, suggesting that piping and dripping effects were strong enough to mask any paleoclimate information. On the contrary, the δ18O records of the Siamese sections of the two stalagmites are virtually identical, suggesting that this parameter is independent of stalagmite growth, being mostly controlled by external factors to the dripping system, probably climate variables (e.g., rainfall composition). Finally, important differences were found when comparing the δ13C time-series. These differences concern general patterns and trends, as well as the average values of each series. This could indicate that δ13C is much more influenced by piping effects than δ18O, and thus more difficult to interpret in terms of paleoclimate. In summary, similar δ18O records have been obtained in both stalagmites, but important differences were found in growth rates and δ13C values. A single record from only one of these stalagmites would have not been representative of the whole environmental system. These results suggest that the paleoclimate interpretations based on growth rates and δ13C records obtained in a single speleothem should be treated with caution. Contribution to project CGL2007-60618-BTE (MCI, Spain), research grants PR-2007-0111 and PR-2007-0197, and the <span class="hlt">Paleoclimatology</span> and Global Change Research Group (UCM-CM-910198). L.R. Edwards and X. Wang are thanked for his advisory help and support during stays of JMC and MJT in the Univ. of Minnesota.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.6303B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.6303B"><span id="translatedtitle">Post Rift Evolution of the Indian Margin of Southern Africa</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baby, Guillaume; Guillocheau, François; Robin, Cécile; Dall'asta, Massimo</p> <p>2016-04-01</p> <p>The objective of this study is to discuss the evolution of the South African Plateau along the Indian margin of Southern Africa. Since the classical works of A. du Toit and L.C. King and the improvement of thermochronological methods and numerical models, the question of the uplift of South African Plateau was highly debated with numerous scenarios: early Cretaceous at time of rifting (Van der Beek et al., J.Geophys.Res., 2002), late Cretaceous (Braun et al., Solid Earth, 2014), late Cenozoic (Burke & Gunnell, Geol.Soc.of America, 2008). Limited attention has been paid on the constraints provided by the offshore stratigraphic record of the surrounding margins. The objective of our study is to integrate onshore and offshore data (seismic profiles and industrial wells) to (1) analyse the infill of the whole margin (21°S to 31°S) from its hinterland to the distal deep water basin, (2) to constrain and quantify the vertical movements. We discuss the impact on accommodation and sediments partitioning, and their significance on South African Plateau uplift history. 1. Sedimentary basins of the Indian margin of Southern Africa are related to the break-up of Gondwana during late Jurassic, resulting in rifts and flexural basins. First marine incursions started during early Cretaceous times (oldest marine outcropping sediments are of Barremian age ~128 Ma). The region developed as a normal continental shelf at the Aptian-Albian transition (~113 Ma). 2. The Cretaceous geological history of the basins is characterized by differential uplift and subsidence of the basement, controlled by structures inherited from break up. As example, major early Cretaceous depocenters of the margin are located on the north of Save-Limpopo uplift (Forster, Paleogography, <span class="hlt">Paleoclimatology</span>, Paleoecology, 1975) showing an eastward drainage pattern, maybe related to a proto Limpopo drainage. Those observations suggest that the escarpment bordering the Bushveld depression is an old relief inherited</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFMED23A1241P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFMED23A1241P"><span id="translatedtitle">Earth2Class Overview: An Innovative Program Linking Classroom Educators and Research Scientists</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Passow, M.; Iturrino, G. J.; Baggio, F. D.; Assumpcao, C. M.</p> <p>2005-12-01</p> <p>The Earth2Class (E2C) workshops, held at the Lamont-Doherty Earth Observatory (LDEO), provide an effective model for improving knowledge, teaching, and technology skills of middle and high school science educators through ongoing interactions with research scientists and educational technology. With support from an NSF GeoEd grant, E2C has developed monthly workshops, web-based resources, and summer institutes in which classroom teachers and research scientists have produced exemplar curriculum materials about a wide variety of cutting-edge geoscience investigations suitable for dissemination to teachers and students. Some of the goals of this program are focused to address questions such as: (1) What aspects of the E2C format and educational technology most effectively connect research discoveries with classroom teachers and their students? (2) What benefits result through interactions among teachers from highly diverse districts and backgrounds with research scientists, and what benefits do the scientists gain from participation? (3) How can the E2C format serve as a model for other research institution-school district partnerships as a mechanism for broader dissemination of scientific discoveries? E2C workshops have linked LDEO scientists from diverse research specialties-seismology, marine geology, <span class="hlt">paleoclimatology</span>, ocean drilling, dendrochronology, remote sensing, impact craters, and others-with teachers from schools in the New York metropolitan area. Through the workshops, we have trained teachers to enhance content knowledge in the Earth Sciences and develop skills to incorporate new technologies. We have made a special effort to increase the teaching competency of K-12 Earth Sciences educators serving in schools with high numbers of students from underrepresented groups, thereby providing greater role models to attract students into science and math careers. E2C sponsored Earth Science Teachers Conferences, bringing together educators from New York and New</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.B13A0890M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.B13A0890M"><span id="translatedtitle">High Spatial Resolution Isotopic Abundance Measurements by Secondary Ion Mass Spectrometry: Status and Prospects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McKeegan, K. D.</p> <p>2007-12-01</p> <p>Secondary Ion Mass Spectrometry, SIMS or ion microprobe analysis, has become an important tool for geochemistry because of its ability study the distributions of elemental and isotopic abundances in situ on polished samples with high (typically a few microns to sub-micron) spatial resolution. In addition, SIMS exhibits high sensitivity for a wide range of elements (H to Pu) so that isotope analyses can sometimes be performed for elements that comprise only trace quantities of some mineral phase (e.g., Pb in zircon) or on major and/or minor elements in very small samples (e.g., presolar dust grains). Offsetting these positive attributes are analytical difficulties due to the complexity of the sputtering source of analyte ions: (1) relatively efficient production of molecular ion species (especially from a complex matrix such as most natural minerals) that cause interferences at the same nominal mass as atomic ions of interest, and (2) quantitation problems caused by variations in the ionization efficiencies of different elements and/or isotopes depending upon the chemical state of the sample surface during sputtering--the so-called "matrix effects". Despite the availability of high mass resolution instruments (e.g., SHRIMP II/RG, CAMECA 1270/1280/NanoSIMS), the molecular ion interferences effectively limit the region of the mass table that can be investigated in most samples to isotope systems at Ni or lighter or at Os or heavier. The matrix effects and the sensitivity of instrumental mass discrimination to the physical state of the sample surface can hamper reproducibility and have contributed to a view that SIMS analyses, especially for so- called stable isotopes, are most appropriate for extraterrestrial samples which are often small, rare, and can exhibit large magnitude isotopic effects. Recent improvements in instrumentation and technique have extended the scope of SIMS isotopic analyses and applications now range from geochronology to <span class="hlt">paleoclimatology</span> to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001Tectp.332...93K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001Tectp.332...93K"><span id="translatedtitle">Tectonic and paleogeographic interpretation of the paleomagnetism of Variscan and pre-Variscan formations of the Bohemian Massif, with special reference to the Barrandian terrane</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krs, M.; Pruner, P.; Man, O.</p> <p>2001-03-01</p> <p> Ordovician age did not produce consistent results; they will require further paleomagnetic and <span class="hlt">paleoclimatologic</span> studies in relation to the data for the Late Cambrian and Early Silurian rocks of the Barrandian area. The analysis of data presented here shows that paleomagnetic declinations of Variscan and pre-Variscan formations reflect paleotectonic rotations following the formation of the respective rocks including rotations induced by the Variscan orogeny and rotation of the European Plate to which the rocks became incorporated. Therefore, paleomagnetic declination of none of the pre-Variscan formations can be identified with paleotectonic rotation either of the Barrandian terrane or even of the whole BM. Magnitudes of horizontal paleotectonic rotations in the BM affected by Variscan tectonism are notably similar to those in the Western Carpathians affected by Alpine deformation. Senses of rotation are, however, different with clockwise rotation prevailing in the BM, and counterclockwise rotations prevailing in the Western Carpathians. Recognition of the effect of horizontal rotations of rock formations, if located in tectonically mobile belts and incorporated into a stable plate during their later history, should be respected while deriving the apparent polar wandering path (APWP).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFMPP53A1387D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFMPP53A1387D"><span id="translatedtitle">NSF-PARCS: A Case Study in Proxy Climate Syntheses for the CCSP Assessment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Duvall, M.; Kaufman, D.; MacDonald, G.</p> <p>2004-12-01</p> <p> of data-visualization products. Initial PARCS data syntheses and presentations were accomplished by combining the synthesis results with methods, visualizations, and primary data accessible through static html pages on the World Wide Web. With the most recent PARCS efforts, we are expanding our approach by co-developing a single, multi-proxy database with the World Data Center for <span class="hlt">Paleoclimatology</span> (WDCP) to house these and other non-PARCS projects. One goal of this database, termed "Open", is to meet the data needs of global-change assessments at the national and international levels. Open will maintain links between primary and synthesized data, allow expanded searches (e.g. searching in spatial, temporal, and/or structural contexts across proxies) and provide improved data viewing via maps, animations and time series. In short, Open includes both the database, and the tools to help the user explore the proxy climate data. An up-dated version of PARCS data will be available through Open by August 2005 and will contribute to the "two-year" goals of the 2003 CCSP.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFMED13B0779S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFMED13B0779S&link_type=ABSTRACT"><span id="translatedtitle">Assessing Climate Misconceptions of Middle School Learners and Teachers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sahagian, D. L.; Anastasio, D. J.; Bodzin, A.; Cirucci, L.; Bressler, D.; Dempsey, C.; Peffer, T.</p> <p>2012-12-01</p> <p>) environmental literacy and inquiry and (2) foster the development of geospatial thinking and reasoning using geospatial technologies as an essential component of the middle school science curriculum. The curriculum is designed to align instructional materials and assessments with learning goals. The following frameworks were used to provide guidelines for the climate change science content in addition to the science inquiry upon which schools must focus: Climate Literacy: The Essential Principles of Climate Sciences (U.S. Global Change Research Program, 2009) and the AAAS Project 2061 Communicating and Learning About Global Climate Change (AAAS, 2007). The curriculum is a coherent sequence of learning activities that include climate change investigations with Google Earth, Web-based interactivities that include an online carbon emissions calculator and a Web-based geologic time-line, and inquiry-based ("hands-on") laboratories. The climate change science topics include the atmosphere, Earth system energy balance, weather, greenhouse gases, <span class="hlt">paleoclimatology</span>, and "humans and climate". It is hoped that with a solid foundation of climate science in the classroom, middle school learners will be in a position to evaluate new scientific discoveries, emerging data sets, and reasonably assess information and misinformation by which they are surrounded on a daily basis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFMPP31A1735C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFMPP31A1735C"><span id="translatedtitle">Tropical Atlantic SSTS at the Last Glacial Maximum derived from Sr/Ca ratios of fossil coral</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cohen, A. L.; Saenger, C. P.</p> <p>2006-12-01</p> <p>The sensitivity of the tropics to climate change is a particularly controversial issue in <span class="hlt">paleoclimatology</span>. At the heart of this controversy are disagreements amongst different proxy datasets regarding the amplitude of glacial-interglacial changes in temperature, particularly at the sea surface. Data obtained from the aragonitic skeletons of massive reef corals have contributed in no small measure to the debate, yielding LGM and deglacial SSTs 5-6°C cooler than today (Guilderson et al., 1994; McCulloch et al., 1999; Correge et al., 2004), that imply a high sensitivity of Earth's climate to changes in boundary conditions (Crowley, 2000). We used SIMS ion microprobe to analyze Sr/Ca ratios of small pieces of Montastrea coral retrieved from a Barbados drillcore (Guilderson et al., 2001). U/Th dates place the samples between 22 and 24 kyr BP. Localized areas of dissolution and re-growth of secondary (diagenetic) aragonite crystals were identified at centers of septa. Sr/Ca ratios of these crystals were higher than Sr/Ca ratios of original coral crystals preserved in adjacent fasciculi and yielded relatively cooler derived SSTs. The original coral crystals, recognized by their size and orientation, were selectively targeted for analysis using a 20 micron-diameter sample spot. Our calibration study using modern corals from Bermuda, St Croix (USVI) and Barbados indicates that Montastrea Sr/Ca is strongly correlated with SST and with annual extension (growth) rate (Saenger et al., 2006). Growth rate of the fossil corals was determined from measurement of daily growth bands identified in petrographic thin-sections. Application of a growth-dependent Sr/Ca-T calibration yielded Barbados SSTs that were, on average, 2.5°C cooler than today during the LGM and ~1°C cooler than today during Heinrich Event 2. Our LGM SSTs are consistent with the original CLIMAP estimates (CLIMAP, 1976) and with more recent Mg/Ca-based SSTs derived from calcitic foraminifera in the Caribbean</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.A53N0348K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.A53N0348K"><span id="translatedtitle">Variations of the glacio-marine air mass front in West Greenland through water vapor isotopes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kopec, B. G.; Lauder, A. M.; Posmentier, E. S.; Feng, X.</p> <p>2012-12-01</p> <p>While the isotopic distribution of precipitation has been widely used for research in hydrology, <span class="hlt">paleoclimatology</span>, and ecology for decades, intensive isotopic studies of atmospheric water vapor has only recently been made possible by spectral-based technology. New instrumentation based on this technology opens up many opportunities to investigate short-term atmospheric dynamics involving the water cycle and moisture transport. We deployed a Los Gatos Water Vapor Isotope Analyzer (WVIA) at Kangerlussuaq, Greenland from July 21 to August 15, and measured the water vapor concentration and its isotopic ratios continuously at 10s intervals. A Danish Meteorological Institute site is located about 1 km from the site of the deployment, and meteorological data is collected at 30 min intervals. During the observation period, the vapor concentration of the ambient air ranges from 5608.4 to 11189.4 ppm; dD and d18O range from -254.5 to -177.7 ‰ and -34.2 to -23.2 ‰, respectively. The vapor content (dew point) and the isotopic ratios are both strongly controlled by the wind direction. The easterly winds are associated with dry, isotopically depleted air masses formed over the glacier, while westerly winds are associated with moist and isotopically enriched air masses from the marine/fjord surface. This region typically experiences katabatic winds off of the ice sheet to the east. However, during some afternoons, the wind shifts 180 degrees, blowing off the fjord to the west. This wind switch marks the onset of a sea breeze, and significant isotopic enrichment results. Enrichment in deuterium is up to 60 ‰ with a mean of 15‰, and oxygen-18 is enriched by 3‰ on average and up to 8 ‰. Other afternoons have no change in wind, and only small changes in humidity and vapor isotopic ratios. The humidity and isotopic variations suggest the local atmosphere circulation is dominated by relatively high-pressure systems above the cold glaciers and cool sea surface, and diurnal</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMPP51B2133W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMPP51B2133W"><span id="translatedtitle">The Devil's Hole Is In The Details</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wallace, M. G.</p> <p>2012-12-01</p> <p> the Heliosphere: Effect of the Solar Journey on the Galactic Cosmic Ray Flux at Earth. Space Science Review DOI 10.1007/s11214-011-9766-x. Kohfeld, Karen E., and Andy Ridgewell, 2009, "Glacial-Interglacial Variability in Atmospheric CO2", Surface Ocean-Lower Atmosphere Processes Geophysical Research Series 187, pp. 251-286. Landwehr, J.M., Sharp, W.D., Coplen, T.B., Ludwig, K.R., and Winograd, I.J., 2011, "The chronology for the δ18O record from Devil's Hole, Nevada, extended into the mid-Holocene: U.S. Geological Survey Open-File Report 2011-1082, 5 p. NOAA <span class="hlt">Paleoclimatology</span> Program - Paleocean Site Data. tr163-19_ssts-fwc.txt # SST data only # File Created: 19-Jan-2005. ftp://ftp.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/sst/tr163-19_ssts-fwc.txt. Patterson, DB, and Farley, KA (1998): Extraterrestrial 3He in seafloor sediments: Evidence for correlated 100 kyr periodicity in the accretion rate of interplanetary dust, orbital parameters, and Quaternary climate. Geochimica et Cosmochimica Acta, 62(23-24), 3669-3682. Shakun, Jeremy D. , Peter U. Clark, Feng He, Shaun A. Marcott, Alan C. Mix, Zhengyu Liu, Bette Otto-Bliesner, Andreas Schmittner & Edouard Bard, 2012, "Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation" Nature Vol 484. pp 49-55.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUSMGP41B..01E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUSMGP41B..01E"><span id="translatedtitle">A review of component analysis based on magnetization curves: state-of-the art and future developments.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Egli, R.</p> <p>2005-05-01</p> <p> hosting sediment. For example, the coercivity of all detrital magnetites is tuned by the transport mechanism (air/water), and the ARM of biogenic magnetites is controlled by the (paleo)redox conditions of the sediment. The consistency of these results supports the linear additivity principle upon which all current magnetic unmixing methods are based. Once the rock magnetic properties of individual components and their statistical distribution is known, the solution of unmixing problems provides important benefits including a great simplification which makes it accessible to non-specialized users. Simplified unmixing algorithms are robust and deliver reliable results based on relatively fast measurements. Two key examples will be presented. In the first example, the magnetic composition of lake sediments is used to develop a model that describes the nonlinear response of a lake to environmental changes. The response function can be used to deconvolute magnetic measurements for <span class="hlt">paleoclimatology</span> reconstructions. The second example deals with an application of component analysis to obtain a low-cost and fast assessment of the air quality in urban areas. A community effort in setting up a database of magnetic components occurring in the most varied environments will provide us with a new, powerful tool for rock- paleo- and environmental magnetism research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMGC21D0998G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMGC21D0998G"><span id="translatedtitle">The Last Glacial Maximum and Termination in the Torres del Paine Region, Southern South America</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Garcia, J.; Hall, B. L.; Kaplan, M. R.; Vega, R. M.; Binnie, S.; Gómez, G.; Santana, F.</p> <p>2012-12-01</p> <p>Deciphering the timing, structure and termination of the local last glacial maximum (LGM) throughout Patagonia (42-55 S) remains one of the key unsolved paleoclimate questions in Quaternary sciences. During the last glaciation, the Patagonian ice sheet formed one ice body along the Patagonian Andes (42-55 S) in southern South America, but previous work has revealed different spatiotemporal ice dynamics along the eastern and western ice margins. The Patagonian Andes is the only landmass that exists at this latitude confronting the southern westerly wind belt, which seems to have played a key role in past glacial and climate changes. Therefore, reconstructing southern Andes glacier history constitutes a key element for understanding the causes of glaciations in the Southern Hemisphere. Major progress has been made to document the local Late-Pleistocene glacier history, particularly in response to recent application of exposure-cosmogenic dating technique in the region, although only sparse well-dated paleoclimate records exist in this vast area. LGM moraine-based records in south Patagonia (~48-55 S) have been developed for the Strait of Magellan area, where full glacial conditions seems to have occurred between ~28.0 - 17.5 ka. Despite that these data seem to confirm previous glacial chronologies developed in north Patagonia and the Chilean Lake District (40-42 S), recent works in Torres del Paine and Última Esperanza basins (50-51 S), suggest that glacial maximum conditions may have occurred earlier (i.e., during Marine Isotope Stage 3) and that ice extent could have been twice the size of previously thought. Here, we discuss <span class="hlt">paleoclimatological</span> implications from our 10Be and 26Al-dating program of moraines in the Torres del Paine region in southern Patagonia. We focused our efforts in the previously undated Río de las Viscachas (RV) I and II moraines, which occur distal to the late-glacial TDP II, III and IV moraines that enclose present lake bodies at the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1612506Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1612506Y"><span id="translatedtitle">The climate - Greenland ice sheet Feedback as simulated by the coupled ice sheet/climate model EC-EARTH - PISM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Shuting; Madsen, Marianne S.; Rodehacke, Christian; Svendsen, Synne H.</p> <p>2014-05-01</p> <p>Recent observations show that mass loss from the Greenland ice sheet has increased during the past decades, in line with the warming trend in the Arctic. Studies have suggested that the ice sheet mass discharge through fast moving outlet glaciers and ice streams may be triggered by intrusions of warm seawater into fjords, implying the possibility for fjord-terminating glaciers to respond to ocean and atmospheric changes on annual to decadal time scales. Meanwhile, the rapid changes in ice sheet topography and surface runoff could alter the atmospheric and ocean circulation. To understand the interactions of ice sheet and atmosphere and ocean, process based, climate - ice sheet coupled models are needed. Recently a fully coupled global climate model with a dynamical ice sheet model for the Greenland ice sheet, EC-EARTH - PISM, has been developed. The model system consists of the atmosphere, ocean and sea ice model system, EC-EARTH, and the Parallel Ice Sheet Model, PISM. The coupling of the PISM includes a modified surface physical parameterization in EC-EARTH adapted to the land ice surface over glaciated regions in Greenland. The PISM ice sheet model is forced with the surface mass balance (SMB) directly computed inside the EC-EARTH atmospheric module and accounting for the precipitation, the surface evaporation, and the melting of snow and ice over land ice. PISM returns the simulated basal melt, ice discharge and ice cover (extent and thickness) as boundary conditions to EC-EARTH. This coupled system is mass and energy conserving without being constrained by any anomaly correction or flux adjustment, and hence is suitable for investigation of ice sheet - climate feedbacks. PISM is initialized with the standard <span class="hlt">paleo-climatological</span> spin-up followed by forcing with the EC-EARTH preindustrial climate to reach an equilibrium state with the model preindustrial climate. The EC-EARTH - PISM system is then integrated under preindustrial conditions until it has reached a</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA03749&hterms=Salt+water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DSalt%2Bwater','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA03749&hterms=Salt+water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DSalt%2Bwater"><span id="translatedtitle">Salt Playas of the Bolivian Altiplano</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2003-01-01</p> <p><p/>In the high plateau of southwestern Bolivia, two large salt deserts, or playas, are located between the eastern and western Andes. The Salar de Uyuni is the largest and highest playa in the world, encompassing an area of more than 9000 square kilometers and situated more than 3600 meters above sea level. It is separated by a range of hills from its smaller neighbor to the north, the Salar de Coipasa. During the Pleistocene the climate of the region was wetter and the entire area was covered by a massive lake. As the waters slowly dried, abundant dissolved minerals were left behind to form the playas. The salt pans are now excellent indicators of rainfall fluctuations within the region and are also important sites for the study of <span class="hlt">paleoclimatology</span>.<p/>These two image pairs from the Multi-angle Imaging SpectroRadiometer (MISR)depict the playas on January 16, 2002 and January 3, 2003. At this time of year the wet season has already begun, and the Salar de Coipaso is usually at least partially flooded. Data from these two dates were processed identically to preserve relative variations in brightness between them. Varying degrees of surface moisture around the two playas are illustrated by the different display techniques of the right and left-hand panels.<p/>At left are two false-color views acquired by MISR's nadir camera. Data from the near-infrared, green and blue bands are displayed as red, green and blue. This spectral display causes bright, wet surfaces to appear blue-green because water selectively absorbs longer wavelengths such as near-infrared. Significantly more standing water is present in the Salar de Coipaso in 2002 than in 2003. However, a stronger signal at the near-infrared band on the 2003 date, which causes the overall hue in the 2003 image to be redder than 2002, suggests an increase in photosynthetic activity (plant growth) at the 2003 date compared with one year earlier.<p/>The right-hand panels were created using only red band data, and are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015EGUGA..17.3673L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015EGUGA..17.3673L&link_type=ABSTRACT"><span id="translatedtitle">Major refit of R/V MARION DUFRESNE and giant sediment corer improvements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leau, Hélène; Réaud, Yvan</p> <p>2015-04-01</p> <p>The french Research Vessel MARION DUFRESNE is equipped with a unique sediment coring facility, called CALYPSO, developed initially by Yvon BALUT at the French Polar Institute, Paul-Emile Victor (IPEV) that operates the vessel 217 days per year in all oceans. The CALYPSO sediment corer retrieves routinely 50 m long undisturbed sediment cores in any water depths, and presently holds the worldwide record of the longest core ever retrieved, that is 64.5 m. This vessel is then a fantastic opportunity for the paleoceanographic community to carry out expeditions at sea. Over the last 20 years, many international IMAGES coring expeditions were organized in all the ocean basins around the world on board the R/V MARION DUFRESNE. More than 1500 cores were retrieved, leading to major advances in the paleoceanography and <span class="hlt">paleoclimatology</span> of the Late Quaternary. The vessel will celebrate her 20th anniversary in 2015 and will undergo a major refit on hull & machineries, public spaces, as well as scientific equipment. The coring capacity is currently being developed to further improve - The length of the retrievable core, with an objective of 75 m long core in routine - The quality of the sediment un-disturbance with a specially designed coring cable with controlled minimum elasticity - The safety of the operations at sea - The quality control of the operations with a suite of sensors and software allowing a detailed monitoring of the coring operation - The time requested for each operation - The environment data collection, in the same time as the coring operations The detailed description of the upgrades will be presented. They consist in a new suite of acoustic sensors that will be integrated on board the vessel during the 4 months ship yard stay from April to July 2015, amongst which a KONSBERG EM122 multibeam echo-sounder and a SBP 120-3 sub-bottom profiler, both mounted on a gondola fitted under the hull of the vessel. This equipment will allow the highest quality images of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013EGUGA..15..326K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013EGUGA..15..326K&link_type=ABSTRACT"><span id="translatedtitle">A 3D Visualization and Analysis Model of the Earth Orbit, Milankovitch Cycles and Insolation.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kostadinov, Tihomir; Gilb, Roy</p> <p>2013-04-01</p> <p>, the seasons, and insolation. Users select a calendar date and the Earth is placed in its orbit using Kepler's laws; the calendar can be started on either vernal equinox (March 20) or perihelion (Jan. 3). Global insolation is computed as a function of latitude and day of year, using the chosen Milankovitch parameters. 3D surface plots of insolation and insolation anomalies (with respect to J2000) are then produced. Insolation computations use the model's own orbital geometry with no additional a-priori input other than the Milankovitch parameter solutions. Insolation computations are successfully validated against Laskar et al. (2004) values. The model outputs other relevant parameters as well, e.g. Earth's radius-vector length, solar declination and day length for the chosen date and latitude. Time-series plots of the Milankovitch parameters and EPICA ice core CO2 and temperature data can be produced. Envisioned future developments include computational efficiency improvements, more options for insolation plots on user-chosen spatio-temporal scales, and overlaying additional <span class="hlt">paleoclimatological</span> proxy data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMPP33E..04H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMPP33E..04H"><span id="translatedtitle">Progress in applying lacustrine alkenones as a quantitative continental paleotemperature proxy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huang, Y.; Longo, W. M.; Theroux, S.; Toney, J. L.; Dillon, J.; Zhao, J.; D'Andrea, W. J.; Hou, J.; Tarozo, R.; Amaral-Zettler, L. A.</p> <p>2013-12-01</p> <p> approach to deconvolute alkenones produced by multiple haptophytes in saline lakes; 7) production of high resolution alkenone-based paleotemperature records from multiple sites (Greenland, Tibetan Plateau etc.). In addition to describing key progress in proxy development, we will show our latest results from studying a series of lakes from Northern Alaska (Toolik lake region), where alkenones are common and the haptophyte alkenone producers are closely related to those in a series of southwestern Greenland lakes. In situ temperature calibrations using water column samples have shown a virtually identical relationship to our previously published data from Greenland. Currently the only paleoclimate assessment for the region is based on pollen assemblages, which have been particularly difficult to translate into quantitative paleotemperature reconstructions. Our preliminary data demonstrate the great potential for obtaining the first quantitative paleotemperature reconstructions using alkenones from these lakes (some of the lake sediments extend to the last glacial maximum), which will fill an important gap in continental <span class="hlt">paleoclimatology</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70000202','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70000202"><span id="translatedtitle">Precipitation rates and atmospheric heat transport during the Cenomanian greenhouse warming in North America: Estimates from a stable isotope mass-balance model</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ufnar, David F.; Ludvigson, Greg A.; Gonzalez, L.; Grocke, D.R.</p> <p>2008-01-01</p> <p> correlate with a mean annual average heat loss of 48??W/m2 at 10??N paleolatitude (present, 8??W/m2 at 15??N). The increased precipitation flux and moisture surplus in the mid-latitudes corresponds to a mean average annual heat gain of 180??W/m2 at 50??N paleolatitude (present, 17??W/m2 at 50??N). The Cenomanian low-latitude moisture deficit is similar to that of the Albian, however the mid-latitude (40-60??N) precipitation flux values and precipitation rates are significantly higher (Albian: 2200??mm/yr at 45??N; Cenomanian: 3600??mm/yr at 45??N). Furthermore, the heat transferred to the atmosphere via latent heat of condensation was approximately 10.6?? that of the present at 50??N. The intensified hydrologic cycle of the mid-Cretaceous greenhouse warming may have played a significant role in the poleward transfer of heat and more equable global conditions. <span class="hlt">Paleoclimatological</span> reconstructions from multiple time periods during the mid-Cretaceous will aid in a better understanding of the dynamics of the hydrologic cycle and latent heat flux during greenhouse world conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1815735B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1815735B&link_type=ABSTRACT"><span id="translatedtitle">Terrestrial cosmogenic 3He: where are we 30 years after its discovery?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Blard, Pierre-Henri; Pik, Raphaël; Farley, Kenneth A.; Lavé, Jérôme; Marrocchi, Yves</p> <p>2016-04-01</p> <p>It is now 30 years since cosmogenic 3He has been detected for the first time in a terrestrial sample (Kurz, 1986). 3He is now a widely used geochemical tool in many fields of Earth sciences: volcanology, tectonics, <span class="hlt">paleoclimatology</span>. 3He has the advantage to have a high "production rate" to "detection limit" ratio, allowing surfaces as young as hundred of years to be dated. Although its nuclear stability implies several limitations, it moreover represents a useful alternative to 10Be in mafic environments. This contribution is a review of the progresses that have been accomplished since this discovery, and discuss strategies to improve both the accuracy and the precision of this geochronometer. 1) Measurement of cosmogenic 3He Correction of magmatic 3He. To estimate the non-cosmogenic magmatic 3He, Kurz (1986) invented a two steps method involving crushing of phenocrysts (to analyze the isotopic ratio of the magmatic component), followed by a subsequent melting of the sample, to extract the remaining components, including the cosmogenic 3He: 3Hec = 3Hemelt ‑4Hemelt x (3He/4He)magmatic (1) Several studies suggested that the preliminary crushing may induce a loss of cosmogenic 3He (Hilton et al., 1993; Yokochi et al., 2005; Blard et al., 2006), implying an underestimate of the cosmogenic 3He measurement. However, subsequent work did not replicate these observations (Blard et al., 2008; Goerhing et al., 2010), suggesting an influence of the used apparatus. An isochron method (by directly melting several phenocrysts aliquots) is an alternative to avoid the preliminary crushing step (Blard and Pik, 2008). Atmospheric contamination. Protin et al. (in press) provides robust evidences for a large and irreversible contamination of atmospheric helium on silicate surfaces. This unexpected behavior may reconcile the contrasted observations about the amplitude of crushing loss. This undesirable atmospheric contamination is negligible if grain fractions smaller than 150 mm are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GeCoA.117..161B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GeCoA.117..161B"><span id="translatedtitle">Leaf wax n-alkane distributions in and across modern plants: Implications for paleoecology and chemotaxonomy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bush, Rosemary T.; McInerney, Francesca A.</p> <p>2013-09-01</p> <p>Long chain (C21 to C37) n-alkanes are among the most long-lived and widely utilized terrestrial plant biomarkers. Dozens of studies have examined the range and variation of n-alkane chain-length abundances in modern plants from around the world, and n-alkane distributions have been used for a variety of purposes in <span class="hlt">paleoclimatology</span> and paleoecology as well as chemotaxonomy. However, most of the paleoecological applications of n-alkane distributions have been based on a narrow set of modern data that cannot address intra- and inter-plant variability. Here, we present the results of a study using trees from near Chicago, IL, USA, as well as a meta-analysis of published data on modern plant n-alkane distributions. First, we test the conformity of n-alkane distributions in mature leaves across the canopy of 38 individual plants from 24 species as well as across a single growing season and find no significant differences for either canopy position or time of leaf collection. Second, we compile 2093 observations from 86 sources, including the new data here, to examine the generalities of n-alkane parameters such as carbon preference index (CPI), average chain length (ACL), and chain-length ratios for different plant groups. We show that angiosperms generally produce more n-alkanes than do gymnosperms, supporting previous observations, and furthermore that CPI values show such variation in modern plants that it is prudent to discard the use of CPI as a quantitative indicator of n-alkane degradation in sediments. We also test the hypotheses that certain n-alkane chain lengths predominate in and therefore can be representative of particular plant groups, namely, C23 and C25 in Sphagnum mosses, C27 and C29 in woody plants, and C31 in graminoids (grasses). We find that chain-length distributions are highly variable within plant groups, such that chemotaxonomic distinctions between grasses and woody plants are difficult to make based on n-alkane abundances. In contrast</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009ems..confE.633S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009ems..confE.633S"><span id="translatedtitle">Recent climate trends and multisecular climate variability: temperature and precipitation during the cold season (October-March) in the Ebro Basin (NE of Spain) betrween 1500 and 2008</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saz-Sanchez, M.-A.; Cuadrat-Prats, J.-M.</p> <p>2009-09-01</p> <p>One of the goals of <span class="hlt">Paleoclimatology</span> is to assess the importance and the exceptional nature of recent climate trends related to the anthropogenic climate change. Instrumental data enable the analysis of last century's climate, but do not give any information on previous periods' precipitation and temperature, during which there was no anthropic intervention on the climate system. Dendroclimatology is one of the paleoclimatic reconstruction sources giving best results when it comes to reconstructing the climate of the time before instruments could be used. This work presents the reconstructed series of precipitation and temperature of the cold season (October-March) In the central sector of the Ebro Valley (NE of Spain). The chronologies used for the reconstruction come on the one hand from the International Tree-Ring Data Bank (ITRDB) and on the other hand from the dendrochronological information bank created in the northern half of the Iberian Peninsula within the framework of the Spanish Interministerial Commission for Science and Technology (CICYT) CLI96-1862 project. The climate data used for chronology calibration and the reconstruction of the temperature and precipitation values are those of the instrumental observatory number 9910 (Pallaruelo) belonging to the Spanish State Meteorological Agency (Agencia Estatal de Meteorología or AEMET), located in the central sector of the Ebro Valley. The reconstruction obtained covers the 1500-1990 period. In order to extend the series up to 2008, instrumental information has been used. Thanks to data from a set of AEMET instrumental observatories close to the one used for chronology calibration, a regional series of temperatures as well as a precipitation one were generated. The series reconstructed through dendroclimatic methods and the regional series do not show statistically significant differences in their mean and variance values. R values between both series exceed 0.85. Taking these statistical characteristics</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMPP13A1805M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMPP13A1805M"><span id="translatedtitle">An Orbital Beat in the Equatorial Atlantic (~18-27 Ma): Reliable Chronometer or Wishful Thinking?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meyers, S. R.; Hinnov, L. A.</p> <p>2011-12-01</p> <p>Orbital-climate theory provides a vital framework for the fields of <span class="hlt">paleoclimatology</span> and geochronology, having spawned advances in our understanding of climate system components, feedbacks, and thresholds, while also leading to a major revision of the geologic time scale. The numerous successes of Pleistocene cyclostratigraphy have motivated the search for orbital influence in strata spanning the Phanerozoic, culminating in the generation of both "anchored" (<50 Ma) and "floating" astrochronologies that can be used to evaluate environmental, biologic and biogeochemical change at very high resolution. Against this backdrop, a common challenge in the development of astrochronologies is the absence of sufficient independent time constraints (e.g., radioisotopic data) to directly calibrate spatial rhythms to temporal periods, and thus quantitatively test for orbital influence. As a consequence, many investigations attempt to test the orbital hypothesis using the "spectral frequency ratio" approach (e.g., the 5:2:1 ratio of short eccentricity, obliquity and precession), and/or by evaluating signal characteristics, such as amplitude modulations of the presumed precession cycle, prior to or following orbital-tuning. None of these approaches - as applied in common practice - explicitly tests the null hypothesis of no orbital influence, leading some to question the veracity of deep-time astrochronology. Here, we revisit proxy data from the equatorial Atlantic Ceara Rise (~18 to 27 Ma; Paelike et al., 2006), a site that has been instrumental in the development of astrochronologies for the Miocene and Oligocene time scale, and has also provided constraints on the theoretical astronomical solutions. Our cyclostratigraphic evaluation employs a method for astrochronologic testing applied to "un-tuned" proxy data, termed Average Spectral Misfit (Meyers and Sageman, 2007). This inverse method explicitly evaluates time scale uncertainty, and provides a formal statistical test of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMPP11B1818G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMPP11B1818G"><span id="translatedtitle">Middle-late Holocene climate variability in La Paz Basin, southern Gulf of California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gómez-Lizárraga, L. E.; Perez-Cruz, L. L.; Fucugauchi, J. U.</p> <p>2013-12-01</p> <p>Sediments from DIPAL III-K47 core collected at 830 m depth in the western slope within the oxygen minimum zone of La Paz Basin, southern Gulf of California provide a detailed record of paleoceanography and <span class="hlt">paleoclimatology</span> for the tropical Pacific on centennial time scales for the past 7300 years. The sedimentary sequence is compose of hemipelagic sediments and is laminated throughout its entire length (145 cm). According to the preliminary age model based on radiocarbon AMS dates, core covers the period from ca 7300 to 1000 cal yr BP. The estimated sedimentation rates are between 0.20 and 0.29 mm/yr. Radiolarian assemblages, geochemical (major and trace elements Al, Ba, Ca, K, Si Ti, Zr and Zr/Al and Ba/Al ratios) and magnetic susceptibility are used as proxies of variations of oceanic circulation patterns, paleoproductivity, aeolian activity and precipitation. Eighty-two intervals were sampled for radiolarians and the core was sampled at 1-cm intervals to produce records of major and trace elements. Factor Analysis of the radiolarian abundances counted in sediments samples identified three assemblages. The first one (Arachnocorallium calvata, Lithomelissa setosa, Lithomelissa thoracites and Peridium longispinum) suggests winter-spring like conditions (cold and dry), Gulf of California Water persistence and a relative increase in productivity that might become from the east-to-west upwelling gradient. The second radiolarian assemblage (Tetrapyle octacantha group and Phorticium pylonium group) was interpreted as stratification of the column water and the incursion of warm, oligotrophic Tropical Surface Water that remind summer-fall like conditions. The third assemblage (Clathrocircus stapedius, Phorticium pylonium group, Lithomelissa pentacantha, Phormacantha hystrix, Phormospyris stabilis scaphipes, Lithomelissa thoracites, Pseudocubus obeliscus, Druppatractus irregularis and Druppatractus variabilis), suggests a mix water column that favors the organic carbon</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_13");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. Their policies may differ from this site.</small> </div> </center> <div id="footer-wrapper"> <div class="footer-content"> <div id="footerOSTI" class=""> <div class="row"> <div class="col-md-4 text-center col-md-push-4 footer-content-center"><small><a href="http://www.science.gov/disclaimer.html">Privacy and Security</a></small> <div class="visible-sm visible-xs push_footer"></div> </div> <div class="col-md-4 text-center col-md-pull-4 footer-content-left"> <img src="http://www.osti.gov/images/DOE_SC31.png" alt="U.S. Department of Energy" usemap="#doe" height="31" width="177"><map style="display:none;" name="doe" id="doe"><area shape="rect" coords="1,3,107,30" href="http://www.energy.gov" alt="U.S. Deparment of Energy"><area shape="rect" coords="114,3,165,30" href="http://www.science.energy.gov" alt="Office of Science"></map> <a ref="http://www.osti.gov" style="margin-left: 15px;"><img src="http://www.osti.gov/images/footerimages/ostigov53.png" alt="Office of Scientific and Technical Information" height="31" width="53"></a> <div class="visible-sm visible-xs push_footer"></div> </div> <div class="col-md-4 text-center footer-content-right"> <a href="http://www.osti.gov/nle"><img src="http://www.osti.gov/images/footerimages/NLElogo31.png" alt="National Library of Energy" height="31" width="79"></a> <a href="http://www.science.gov"><img src="http://www.osti.gov/images/footerimages/scigov77.png" alt="science.gov" height="31" width="98"></a> <a href="http://worldwidescience.org"><img src="http://www.osti.gov/images/footerimages/wws82.png" alt="WorldWideScience.org" height="31" width="90"></a> </div> </div> </div> </div> </div> <p><br></p> </div><!-- container --> </body> </html>