This is describes the field geology of the Columbia River Basalt Group and Yakima Fold Belt in the central Columbia Basin
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The Mississippi Fan fold belt, located in the deep Gulf of Mexico beneath the upper and middle Mississippi Fan, is characterized mainly by basinward-verging anticlines and associated thrust faults. The fold belt extends approximately 300 km eastward and is approximately 50 km wide. Based on correlations with deep ...
The structure and present-day dynamics of the Alps interms of geodesy and gravimetry are discusssed.
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The Overthrust and Disturbed belt of west-central Montana is a geologically complex, thrust-faulted and folded region with reported hydrocarbon occurrences, potential source and reservoir rocks, and structures for entrapping oil and gas. This region is compared with the major productive parts of the Western Overthrust belt in Alberta ...
Central European tectonics can be subdivided into (1) Pannonian-type basins, related Carpathian-type fold belts and their foredeeps, (2) Alpine-type fold belts and their foredeeps, and (3) intracratonic-type fold belts. The first basin type is the result of rolling back of ...
Six new Rb-Sr isochrons on samples of rocks of the setentrional portion of the Ribeira folded belt are presented and discussed with others geochronological and geological data. The main object of this study is the search of the understanding of the geodyn...
National Technical Information Service (NTIS)
are identified separately. We tested this technique on data collected from a 1967 smallpox epidemic in Abakaliki . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2.3 Characterization of smallpox outbreaks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 5.1 The data: the ...
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The northern part of the Araguaia Fold Belt (AFB) outcrops in a N-S direction for about 400 km in the state of Tocantins. Dome-like structures occur in this fold belt also in a N-S direction. Both deformation and metamorphism increase from the West to the...
The widespread occurrence of geothermal manifestations in Nigeria is significant because the wide applicability and relative ease of exploitation of geothermal energy is of vital importance to an industrializing nation like Nigeria. There are two known geothermal resource areas (KGRAs) in Nigeria: the Ikogosi Warm Springs of Ondo State and the Wikki Warm Springs of Bauchi State. These surficial ...
- served along transect TN1 for the stations located on the Zagros folded belt (DELO�HAFT) relative to the Zagros folded belt (SOLE�KORD�CHEL) and Central Iran (SHOL�KHON), and along transect TN3 system in the Zagros Mountain Belt, Iran, show that the accommodation of the convergence of ...
The Zagros mountains of SW Iran are one of the most seismically active inter-continental fold-and-thrust belts on earth, and an important element in active tectonics of the Middle East. The basement-involve in this active fold-thrust belt is underlain by numerous seismogenic blind basement thrust faults covered by ...
NASA Astrophysics Data System (ADS)
The Perdido fold belt in the Alaminos Canyon OCS protraction area contains some of the largest, untested structural traps within US waters. The overall structural geometry of the fold belt is relatively simple, although individual structures show a complex array of structural styles. Previous interpretations have ...
The results of detailed mapping of a well exposed (by a large fume kill) Archean Michipicoten greenstone belt of Ontario is discussed. Numerous structural features are described including soft sediment deformation, thrust faults, isoclinal folds, and sill...
Gravity data are used to support the conclusion that the Brooks Range structure is continuous across the Chukchi Sea with the Chukchi-Anadyr fold belt. A morphological reconstruction of this section of the mobile belt that is consistent with known geologi...
Antarctica New Zealand, New Zealand Antarctic Institute, ... and New Zealand: Implications for the tectonic setting of the Lachlan Fold Belt in Antarctica. ...
NASA Website
Sep 9, 2009 ... WYOMING INTERMONTANE BASINS ... This basin is bounded on the west by the Wyoming Overthrust Belt (Figure T-6.2), in which folded ...
of India, consisting of the following states: Nagaland, Arunachal Pradesh, Mizoram, Manipur, Meghalaya. The contours pass- ing through Manipur and Mizoram are parallel to the folded belt of Tripura and western part
Despite its long history of exploration, the Sulaiman fold and thrust belt is a poorly known structure and detailed structural and geochemical investigations are vital for the successful exploration, evaluation and exploitation of any hydrocarbons. Recent nappe and duplex structural models provide a framework for exploration. Surface and subsurface data ...
The presence of suitable structures, source and reservoir rocks, and oil and gas shows makes the Disturbed belt of west-central Montana a potential area for hydrocarbon exploration. Essentially part of the Overthrust belt that runs through several Rocky Mountain states, the Disturbed belt is a zone of thrust-faulted and ...
This paper is composed of three small articles dealing with the development and use of belt conveyors in the Neyveli Lignite Project of India and at the West Cliff Colliery, New South Wales. The paper describes the design and performance of these conveyors both in a surface mining and underground mining environment. The conveyors at the West Cliff site are a ...
The Perdido fold belt is the compressional toe of the complex system of detached structures in the western Gulf of Mexico. Located in the Alaminos Canyon protraction area in ultra deep-water, this extensive fold belt has the potential to accommodate large amounts of hydrocarbons. These folds ...
Detailed photogeologic study and field checks indicate the North Sinai folds are associated with northwest-dipping upthrusts, especially on their southeastern steeply dipping flanks. These northeast-southwest-plunging folds include both large folded ranges (tens of kilometers long, e.g., Gebels Yelleq, El Maghara, and El Halal) and ...
The Towaliga-Goat Rock and Bartletts Ferry deformation zones are major tectonic boundaries of the southeastern Piedmont. The Towaliga zone separates the Pine Mountain Belt and the Inner Piedmont and the Goat Rock and Bartletts Ferry Zones separate the Pine Mountain and Uchee Belt. The Uchee Belt is composed of granitic gneisses and ...
The thick-bedded, competent quartzose sandstones, conglomerates, and siltstones of the Moodies Group (<3,225 Ma) influence structural style in the ~3.1-3.5 Ga Barberton Greenstone Belt. Moodies Group rocks are folded into a train of tight, subparallel, doubly plunging, overtuned synclines separated by narrow, strike-parallel fault zones. Structural ...
Although geoscientists have interpreted thousands of salt sheets in many basins worldwide, there has been little systematic work on salt tectonics at earth surface. Most salt diapirs in the world pierced during extensional events, whereas, salt in regional shortening in collisional orogens have been rarely documented. The Kuqa foreland fold� thrust belt ...
at the back of the wedge (hereafter referred to as the ``decollement sole-out depth''). Likewise, the surface wedge and the foreland may be accommodated by introduction of material into the back of the wedge (left to the back of the wedge, v. The depth at which the basal wedge decollement flattens at B01410 HILLEY ET AL
The Proterozoic Painco-Alto Fold Belt is situated in the central portion of the Borborema Province and it probably is just a segment of a longer structural development encompassed between the Patos (N) and Pernambuco (S) lineaments. The geochronological s...
The Cordilleran fold and thrust belt in central Utah may be divided into a western belt of Precambrian to lower Mesozoic strata shortened above ramp-style thrust faults and an eastern belt of folded middle to upper Mesozoic rocks. Shortening in the eastern foldbelt occurred above a ...
of the lithosphere, probably related to the Karoo magmatic event and to the opening of the South Atlantic Ocean. Key Africa Kheis Belt Kimberley CL 1 2 Namibia Botswana Cape Fold Belt Namaqua-Natal Belt Vredefort Kaapvaal of the lithosphere, which seems to be spatially as well as temporally correlated with the ...
Fossil evidence indicates that the Carolina Slate belt, interpreted as a late Precambrian to early Paleozoic volcanic arc, is a terrane exotic to North America (Secor et al., 1983). Petrographic and isotopic evidence (Farrar, 1983) suggests that the Raleigh belt, located between the Western and Eastern Carolina Slate belts, is at least ...
the transmission rate and the social network, using data from a 1967 smallpox epidemic in Abakaliki, Nigeria, a smallpox outbreak occurred in the town of Abakaliki, Nigeria [3, 4]. The outbreak was largely confined) smallpox victims. We investigate the problem under two separate simplifications. We first assume
The Sawtooth Range forms part of the Montana Disturbed Belt in the Front Ranges of the Rocky Mountains, along strike from the Alberta Syncline in the Canadian Rockies. The belt developed in the footwall to the Lewis Thrust during the Sevier orogeny and is similar in deformation style to the Canadian Foothills, with a series of stacked thrust sheets ...
Eastern Sichuan Basin is confined by two thin-skinned fold-thrust belt, NW-trending Southern Daba Shan (Shan=Mountain) (SDB) in the northeast and NNE- or NE-trending Western XueFeng Shan (WXF) in the southeast, which constitute two convergent salients convex to the inner basin respectively. Although many factors can lead to the formation of ...
Most models for the tectonic history of the western Brooks Range treat Proterozoic and lower Paleozoic metamorphic rocks exposed in the southern part of the range as passive structural basement vertically uplifted late in the Mesozoic orogenic episode. Mapping in the metamorphic rocks shows that they can de divided into two structurally and metamorphically distinct belts, both ...
Closure of Neotethys during the Arabia-Eurasia collision has produced a wide belt of deformation in the southern foreland of the Greater Caucasus. Since 5 Ma, the main locus of shortening has shifted from within the Greater Caucasus southward to the Kura fold-thrust belt in Georgia and Azerbaijan. This belt is ...
After over 70 years of hydrocarbon exploration in the Papuan fold belt of PNG (Papua New Guinea) there have been a number of hydrocarbon discoveries over recent years that have confirmed its potential as a significant producing province. The Papuan basin developed during the early Mesozoic as part of the northeast corner of the Australian passive margin. ...
The Disturbed Belt of west-central Montana consists of a zone of Laramide convex-eastward thrusts and fold that include the major Eldorado-Lombard overthrust that has brought Precambrian rocks of the Belt Supergroup eastward over Paleozoic and Mesozoic strata. Most of the Disturbed Belt is east of and structurally ...
The Zagros mountains extends over 1800 km from Kurdistan in N-Iraq to the Strait of Hormuz in Iran and is one of the world most promising regions for the future hydrocarbon exploration. The Zagros Mountains started to form as a result of the collision between the Eurasian and Arabian Plates, whose convergence began in the Late Cretaceous as part of the Alpine-Himalayan orogenic system. Geodetic ...
The Abitibi belt is one of the largest and most extensively studied Late Archean greenstone belts. The structural geology of the Abitibi belt consists of one generation of upright to slightly overturned, doubly plunging first-order folds with half-wavelengths of 20 60 km, and E W-striking, steeply dipping fault ...
Folding of axial plane cleavage can occur during progressive deformation without a change in the overall background flow. Two field examples of upright (Lachlan Fold Belt, SE Australia) and recumbent (Naukluft Nappe Complex, central Namibia) folds are presented, in which strongly refracted pressure solution ...
The Carolina slate belt and the Milton belt represent fundamental terranes within the southern Appalachian Piedmont. The nature of the boundary that separates mainly meta-igneous rocks of the Carolina slate belt from higher grade gneisses and schists of the Milton belt is controversial. Conflicting interpretations ...
The oldest rocks in the mainland southeastern Australian segment of the (Palaeozoic) Lachlan Fold Belt are Cambrian greenstones which outcrop in three narrow linear belts separated by Lower Palaeozoic marine troughs in which many thousands of meters of predominantly greywacke-shale sediments accumulated. The greenstone ...
The high level of exploration interest in Papua New Guinea has developed in large part because of recent discoveries in the western Papuan fold and thrust belt and shows in the adjacent foreland region. Results from recent drilling in the Iagifu/Hedinia area by a Chevron-led joint venture have outlined several pools in culminations along a 50 km long ...
The W-NW trending Greater Caucasus Mountains form the northern edge of the Arabia-Eurasia collision and accommodate much of the NW-SE convergence, but the evolution of this first-order structural system remains enigmatic. Thermochronologic work suggests that the Greater Caucasus initiated in the W and that uplift propagated E overtime. Since 5 Ma, the main locus of shortening has shifted from ...
The phenomenon of Kink banding is well known throughout the engineering and geophysical sciences. Associated with layered structures compressed in a layer-parallel direction, it arises for example in stratified geological systems under tectonic compression. Our work documented it is also possible to develop super large-scale kink-bands in sedimentary sequences. We interpret the Bachu ...
In order to understand the interplay between vein development and folding in the carbonates of the Oligo-Miocene Asmari Formation (one of the main hydrocarbon reservoir rocks) in Iran, several anticlines have been investigated in the central part of the Zagros folded belt. Combining observations of relative chronology between veins ...
Thickness variations record paleostructural relief and thus provide a method of calculating the growth rate of the Saddle Mountains. These calculations indicate the uplift was growing at about 250 m/my during Grande Ronde time but slowed to less than 40 m/my by the end of the Miocene. Thickness variations and amount of uplift of suprabasalt sediments indicate this low average rate persisted at ...
Remapping of upper Proterozoic and Cambrian rocks in the northern Bannock Range south and east of Pocatello, Idaho, indicates a polyphase deformation history characterized by both shortening and extension. Map-scale folds and faults, related to shortening in the transition zone between the Idaho-Wyoming thrust belt and the hinterland to the west, are ...
The occurrence of strongly overturned to recumbent anticlines in shallow foreland thrustfold belts is not well explained by the available geometric models of thrust-related folding when a very large amount of forward shear cannot be assumed and, for growth anticlines, when the tectonic uplift rate is greater than the sedimentation rate. We have developed ...
There are a large number of numerical finite element studies concerned with modeling the evolution of folded geological layers through time. This body of research includes many aspects of folding and many different approaches, such as two- and three-dimensional studies, single-layer folding, detachment folding, ...
The Songpan-Garze fold belt, located in the eastern part of the Tibetan Plateau, covers a huge triangular area bounded by the Yangtze (South China), the North China and the Tibetan Plateau blocks. In the northeastern part of the Songpan-Garze fold belt, the Yanggon and Maoergai granitoids provide insights into ...
During the Brasiliano-pan-African orogeny, a complex continental-scale pattern of east-west transcurrent shear zones and northeast-trending fold belts formed in the northern and central Borborema province of northeastern Brazil. The east-west shear zones have been usually regarded as slightly younger features, but the study of the most spectacular case of ...
Measurements on either side of the Kazerun fault system in the Zagros Mountain Belt, Iran, show that the accommodation of the convergence of the Arabian and Eurasian Plates differs across the region. In northwest Zagros, the deformation is partitioned as 3-6 mm yr-1 of shortening perpendicular to the axis of the mountain belt, and 4-6 mm yr-1 of dextral ...
The Tertiary fold-thrust belt in Oscar II Land, central Spitsbergen, consists of three major zones of distinct structural style: (1) a western basement-involved fold-thrust complex, (2) a central zone of thin-skinned fold-thrust units above a decollement in Permian evaporites, and (3) an eastern zone characterized ...
Structural data and cross sections from the eastern part of the Devonian-Carboniferous fold belt of the Meguma Terrane give insight into its structural development and crustal tectonics. The sandy Goldenville Formation, the active competent member during buckling, formed a multilayer several kilometers thick that lay beneath the denser, softer muds and ...
Recently shot 3D seismic data allowed for a detailed interpretation, aimed at the tectonic evolution of the central part of the Mid-Hungarian Shear Zone (MHZ). The MHZ acted as a NW vergent fold and thrust belt in the Late Oligocene. The intensity of shortening increased westwards, causing clockwise rotation of the western regions, relatively to the mildly ...
This structural geology field trip in the Hudson Valley region reinforces class discussions about fold and thrust belts and thin-skinned tectonics. Students observed a ramp anticline over a ramp-flat geometry fault. The anticline has minor faulting and veining in the hinge zone and folding occurred by flexural slip (evident from ...
NSDL National Science Digital Library
in Taiwan: Geological Society China Memoir 4, p.67-89. Suppe, J. (1986) Reactivated normal faults in the western Taiwan fold thrust belt: Geological Society China Memoir 7, p.187-200. #12;36 Characteristics
In the upper parts of the earth's crust there are two main complexes of structures: linearly expanding concentration belts of rock deformations, usually discontinous and in some cases folding, depressions and uplifts of different nature and dimensions, is...
Venus is more similar to Earth than to any other planet. It has elevated regions associated with marginal fold and thrust belts, fracture zones that extend tens of thousands of kilometers, crustal swells and shields that are hundreds of kilometers in diam...
The Oak Ridge Reservation (ORR) is located in the northwestern part of the Valley and Ridge province in east Tennessee. The Valley and Ridge province is the topographic expression of the southern Appalachian foreland fold-thrust belt, which formed during ...
This article comprises the seismic profile, and its important characteristics, of Southwest Montana, as well as a brief overview of the oil and gas exploration potential in the area and a description of the drilling there thus far.
The Southern Antilles region is the least investigated link in the Pacific folded belt, its study having been inhibited by extremely severe climatic conditions and distance. Recent studies in the area are discussed. Many of the key elements of the palinsp...
Some of the results of the mapping by the Geological Survey Department of Jamaica in the east-central area of the island are presented. The previous division of the Lower Eocene rocks into an ascending three-fold sequence of continental, volcanic and mari...
Our search for large compressional structures similar to the Coprates rise reveals that the rise is part of a group of about three dozen structures (the 'Thaumasia fold belt') that encircles the southern part of the Tharsis region. Similar structures are ...
Interpretation of bathymetric, magnetic and seismic reflection surveys in the Beata Ridge region provide evidence for two distinct geologic provinces: (1) the Beata Ridge system; and (2) a Late Cenozoic deformational fold belt north of Venezuela and Colom...
diabases. 0 to -60 agal. Trans-Amazonian age (T). Guaporf Shield. -30 m9al, locally. Paragusy-Araguaia positive feature. Broziilian Cycle fold belt ...
Reconstructions of southern Gondwana place Tasmania at the triple junction of Paleozoic Australia, Antarctica, and New Zealand. Tasmania, however, differs in pre-Jurassic stratigraphy and structural style from the southeastern Australian mainland and northeast Victoria Land, Antarctica. Most notably, (1) Precambrian basement is exposed in Tasmania but not in the Lachlan fold ...
A continuous structure of uplifts extending through the entire Mediterranean fold belt, controls the distribution of ore and oil deposits. In Romania, the ore and oil deposits are confined to the continuous structure. (DLC)
Magnetic and radio echo soundings, geophysical measurements and gravity surveys ... over the Transantarctic Mountains and the Ross Sea/McMurdo Sound area. ... and where major anomalies were detected by the airborne magnetic profiling. ... investigate the boundary fault between the West Antarctic fold belt and the ...
Nov 19, 1993 ... The entire fold mountain belt of southern Africa appears as green, ... view yet of Mount Everest, the highest mountain in the world at 29028 feet. The ... West Point can be seen on the western bend of the Hudson River. ...
The Maria fold-and-thrust belt (MFTB) is a narrow belt of Mesozoic crustal shortening that is characterized by generally south vergent folds and thrusts that commonly displace Proterozoic crystalline rocks over deformed and metamorphosed Paleozoic and Mesozoic strata. The MFTB is cut by a south to southeast ...
We use two computer programs to analyze the propagation of multiple thrust faults and their influence on the geometry of a thrust belt. They use algorithms based on current equations of fault propagation to generate graphical simulations. The simulations are used to demonstrate a model of thrust propagation and thrust belt development that fits current ...
Fault-propagation folds constitute an important trap style in fold and thrust belts. In these structures, propagating thrust fault loses slip upsection by transferring its shortening to a fold developing at its tip. Area-balanced theoretical models show that for any given footwall cutoff angle (q), small changes in ...
The Zagros fold and thrust belt is a seismically active orogen, where actual kinematic models based on GPS networks suggest a north-south shortening between Arabian and Eurasian in the order of 1.5-2.5 cm/yr. Most of this deformation is partitioned in south-southwest oriented folding and thrusting with northwest-southeast to ...
An equation is presented to describe the overall balance of energy in a steady-state active fold-and-thrust belt. The equation states that the rate at which both mechanical and heat energy are added from external sources is equal to the sum of the rate of work performed against gravitational body forces and the rate at which waste heat flows out of the ...
This article contains the first data on the chemical composition and tectonic conditions of deposition of Paleozoic terrigenous sediments of the Ols'doi Terrain located in the eastern portion of the Central Asian Fold Belt. The data obtained suggest that at the initial stage deposition of sediments took place in the environment of a passive continental ...
An active fold-and-thrust belt in unchanging tectonic and climatic conditions exhibits a dynamic steady state, with the flux of rocks accreted at the toe balanced by the flux of rocks eroded off the top. Rocks entering the toe are buried and heated before they are uplifted and eroded; this results in a characteristic map pattern of low-grade metamorphism ...
In this contribution we first investigate the impact of erosion on the geometry and kinematics of the central Argentine Aconcagua Fold-and-Thrust Belt (AFTB) using an integrated analog (sandbox) and numerical (Gale) modeling approach in which mass removal from the topographic surface is limited by the rate of fluvial bedrock incision. This method unifies ...
Using a new implementation of critical taper wedge mechanics, we investigate the relationship between structural styles and calculated mechanical strength properties in two unique fold and thrust belts. Through the analysis of regional seismic reflection profiles and detailed bathymetric data, we define the wedge taper geometry of the ...
The Zagros Mountains result from the ongoing collision between the Arabian and central Iran plates. The main features of the eastern Zagros are (1) numerous emerged or buried salt diapirs, made up of Late Precambrian Hormuz salt and (2) the irregular along-strike shape of the collision-related detachment folds with frequent bending. To understand this layout, four geological ...
Outcrops of Trenton and younger limestones and shales between Plattsburgh, New York, and Malletts Bay, Vermont, show eastwardly increasing progressive deformation fabric in the foreland fold and thrust belt of northwestern Vermont. The deformation sequence within the calcareous Stony Point and Iberville shales is: 1) bed-parallel slip, marked by grooved ...
Recurrent uplift of the Ouachita fold belt in Oklahoma coincided with the disruption of the Arkoma basin following the deposition of the Boggy Formation (early Desmoinesian time). The Boggy, composed of sandstone-shale sequences that record southerly progradation of coal-bearing, fluvially dominated deltaic complexes into the Arkoma basin, was ...
Plate interactions in northeastern Russia have been studied using seismological and structural field investigations; however, tectonic interpretations in the region remain widely debated and unknown. The Chersky fold and thrust belt in northeastern Russia is situated on the western margin of the North American Plate adjacent to the Indigirka-Zyryanka ...
Weldon Beauchamp, and David McDonald,TransAtlantic Petroleum Corp. 5910 N. Central Expressway, Suite 1755, Dallas, TX 75206 weldon@tapcor.com, 214-395-7125 The Zagros fold belt extends northwest from Iran and Iraq into southeastern Turkey. Large scale fault related folds control the topography of this region and the path of the Tigris ...
The development of structural elements and finite strain data are analysed to constrain kinematics of folds and faults at various scales within a Proterozoic fold-and-thrust belt in Pranhita-Godavari basin, south India. The first order structures in this belt are interpreted as large scale buckle ...
A preliminary Alleghanian tectonothermal sequence has been developed for the Appalachian fold and thrust belt along a transect where the sequence of macro-structural features (major thrusts and folds) is known from detailed mapping. Combining this sequence with detailed meso- and micro-structural, thermal, and geochronologic data ...
The Tulare fold belt is a series of asymmetric, generally northeast-verging anticlines and synclines in the Pliocene-Pleistocene Tulare Formation that trend northwestward through the Cymric-McKittrick fields. Anticlines within the deformed belt generally originated as fault propagation folds above decollements, the ...
The Michipicoten Greenstone Belt extends for about 150 km ENE from the northeastern angle of Lake Superior. In common with many other Archean greenstone belts, it is characterized by generally steep bedding dips and a distribution of major lithologic types suggesting a crudely synclinal structure for the belt as a whole. Detailed ...
Variations in the Earth's trapped (Van Allen) belts produced by solar flare particle events are not well understood. Few observations of increases in particle populations have been reported. This is particularly true for effects in low Earth orbit, where manned spaceflights are conducted. This paper reports the existence of a second proton belt and it's ...
PubMed
Aluminum-in-hornblende barometry of Alleghanian granitoid plutons in the southern Appalachian Piedmont provides new constraints on synorogenic, vertical crustal displacements. Systematic differences in depths of emplacement between plutons in the Carolina slate belt and the Charlotte and Kings Mountain belts appear to confirm previously proposed ...
A belt of deformation in the Solimoes basin of northwestern Brazil extends east-northeast from near the Peruvian border for about 1300 km. The belt is characterized by the en echelon arrangement of folds and faults interpreted as the result of right-slip displacements in a transpressive regime. The structures were formed during Late ...
A self-consistent theory for the mechanics of thin-skinned accretionary Coulomb wedges is developed and applied to the active fold-and-thrust belt of western Taiwan. The state of stress everywhere within a critical wedge is determined by solving the static equilibrium equations subject to the appropriate boundary conditions. The influence of wedge ...
The Eastern Cordillera (EC) of Colombia marks the eastern boundary of Cenozoic fold-thrust deformation in the northern Andes. It is a classic example of an inversion belt formed in the retro-arc region, in this case superimposed on a Triassic/Jurassic to Cretaceous intracontinental rift system of northern South America. Ongoing thrust reactivation ...
The P�T record of synchronous magmatism, metamorphism and deformation at Petrel Cove, southern schists in the thermal aureole of the Victor Harbor Granite at Petrel Cove, in the southern Adelaide Fold on the P�T record preserved in porphyroblastic schists at Petrel Cove in the Victor Harbor region
Principles of step-faulting are simulated in computer-synthesized and balanced structural cross sections of faulted and folded terranes. The author uses forward modeling to generate balanced cross sections at all stages of growth, and shows that purportedly balanced cross sections may include impossible intermediate stages.
* , XAVIER ROBERT, JEAN-LOUIS MUGNIER, MATTHIAS BERNET, PASCALE HUYGHE AND ERIKA LABRIN Laboratoire de & Avouac, 2000; Mugnier et al., 2004) inferred from folded and uplifted river terraces. They are also equal to Quaternary shortening rates across the Siwalik fold belt (Mugnier et al., 2004) and Mio- Pliocene shortening
A north-south structural transect through the south-central Brooks Range, Alaska, exposes three lithologically distinct, fault-bounded packages of rock, all regionally metamorphosed during the Late Jurassic to Early Cretaceous contractional deformation that formed much of the Brooks Range fold and thrust belt. These are, from south to north and ...
The northern Cordilleran fold-and-thrust belt in Canada and Alaska is at the boundary between the broad continental margin mobile belt and the stable North American craton. The fold-and-thrust belt is marked by several significant changes in geometry: cratonward extensions in the central Yukon ...
The West Spitsbergen fold-and-thrust belt formed along the transform plate boundary between Greenland and the western Barents Sea during Paleocene-Eocene breakup in the northern North Atlantic. Approximately 20�40 km margin-perpendicular shortening accumulated in the belt has been attributed to transpression and strain partitioning ...
The Michipicoten greenstone belt, Ontario, experienced a complex history of folding, faulting, and fabric development. Near Wawa, a major east-west contact, here named the Steep Hill Falls (SHF) contact, extends entirely across the belt. The SHF contact is both an angular unconformity and a fault and is interpreted to be a regionally ...
The Haitian fold-and-thrust belt is the major mountain belt of Haiti (western part of Hispaniola, Greater Antilles) and resembles a compressive restraining bend between the two major faults which have driven the opening of the Cayman Basin since the Eocene. During the rifting stage, from the middle to the late Eocene, this area ...
Mechanically induced calcite twins in veins and host rocks of Late Cretaceous to Miocene age in Iran have been used to determine regional Arabia-Eurasia collisional stresses. A late folding stress regime with a compression oriented 025� (�15�) has been identified across the Zagros belt and the southern Iranian Plateau. This late Neogene stress ...
The Falls Lake melange crops out in the eastern Piedmont of North Carolina between the Carolina slate belt and the Raleigh belt. The melange is composed of mafic and ultramafic blocks and pods of diverse shapes and sizes, dispersed without apparent stratigraphic continuity, in a matrix of pelitic schist and biotite-muscovite-plagioclase-quartz gneiss. ...
A low-Earth orbit nuclear detonation could produce an intense artificial radiation belt of relativistic electrons. Many satellites would be destroyed within a few weeks. We present here simple estimates of radiation belt remediation by several different techniques, including electron absorption by gas release, pitch angle scattering by steady electric and ...
Deep-seismic reflection profiles across parts of the Central Appalachian orogenic belt indicate that the crust here includes an exposed Paleozoic fold-and-thrust belt that is mainly soled in Proterozoic Grenville basement. Translation strain in the foreland and Highlands resulting from Paleozoic orogenesis is as much as 25 km, ...
The presence of asymmetric drag folds is characteristic of many ductile shear zones. The origin of these folds is variable, as their development may predate, be synchronous or postdate the shearing events. Folds and other meso- and micro- structures within shear zones are often asymmetric. However, their finite geometry, degree of ...
Geomorphological and geophysical methods combined with borehole information were employed to search for possible subrecent small-scale vertical movement along the anticlinal fold belt of the central Negev, Israel. Such tectonic deformation might indicate displacement on the buried reverse faults underneath the anticlines. Variations in the thickness of the ...
Intraplate deformation can occur at great distances from synchronous plate boundaries and is most likely the result of strain concentrations into weak zones. These weak zones may be pre-existing crustal heterogeneities such as faults, thermally weakened zones due to magmatism and/or the effects of a thick sedimentary cover, or mechanical contrasts between adjacent crustal blocks. Intraplate ...
This dissertation investigates the mechanics of fault-bend folding using the discrete element method (DEM) and explores the nature of tear-fault systems in the deep-water Niger Delta fold-and-thrust belt. In Chapter 1, we employ the DEM to investigate the development of growth structures in anticlinal fault-bend ...
Daba Shan is a fold-and-thrust belt located on the northeastern margin of the Sichuan Basin, central China orogen. It is the transitional zone between the Sichuan Basin and Qinling orogenic belt, and it is located in the middle part of the Mianlu suture zone which is the boundary between the Qinling orogenic belt ...
A detailed structural analysis of several selected areas of Ovda Regio provides evidence of a complex tectonic evolution. We have reported thrusting in the marginal fold belts indicating together with the presence of short-wavelength folds a significant amount of shortening. Extensional tectonics postdate at least in some locations ...
The Zagros fold-and-thrust belt has formed in detached Phanerozoic sedimentary cover rocks above a shortened crystalline Precambrian basement and evolved through the Late Cretaceous to Miocene collision between the Arabian and Eurasian plate, during which the Neotethys oceanic basin was closed. Deformation is partitioned in SW directed ...
Students use patterns observed on an outcrop geologic map and stereoplots to study the structures in this real, polyphase deformed and metamorphosed belt in the United Kingdom. There are at lest two, and perhaps three episodes of deformation recorded on this map. Students learn how to systematically analyze polyphase folds and complex mesoscopic fabrics by ...
The mechanics of folding and buckling have long been the focus of thorough analytical studies, and of physical and numerical experiments. As a consequence, the folding of one single viscous layer is now well understood. However, the application of such single layer folding does generally not allow us to accurately reproduce the ...
The west Texas segment of the Grenville orogen includes an oblique, dextral, transpressive zone. The orogen exposed near Van Horn, Texas, displays a transition from the mid-amphibolite-facies metamorphic core to a foreland fold and thrust belt. In this paper, detailed structural mapping and analyses, presented for key exposures of the metamorphic rocks, ...
Folding and thrusting are key processes in accommodating shortening in evolving orogens. In the outer parts of mountain belts, the combination of tectonism and sedimentation often leads to viable petroleum systems where folds trap migrating hydrocarbons. A key aspect of the success of these traps is the 3D fold ...
The front of the Cordilleran fold and thrust belt in western Montana follows the disturbed belt in the north, merges with the southwest Montana transverse zone in the west-central part of the region, and in southwestern Montana is marked by a broad zone characterized by complex interaction between thrust belt ...
The lower Murphy belt in the central western Blue Ridge is interpreted to be correlative to the Early Cambrian Chilhowee Group of the westernmost Blue Ridge and Appalachian fold and thrust belt. Basal Murphy belt depositional sequence stratigraphy represents a second-order, type-2 transgressive systems tract ...
The main Precambrian terrains recognized in Brazil comprise the Amazonian, S�o Francisco and Rio de la Plata cratons, surrounded by Neoproterozoic Brasiliano fold belts, making up the Borborema, Mantiqueira and Tocantins provinces. The Amazonian craton comprises an Archean core, surrounded by Paleoproterozoic terrains (Maroni-Itacaiunas, ...
The geometry of folds is essential for understanding folding mechanism and rock properties during deformation. Thus, it is crucial to be able to characterize fold geometries in an accurate fashion. A variety of the methods describing fold geometry exists in the literature, however they are mainly limited to the ...
Geologic mapping and structural analysis of east-central Mexico were conducted to assess the architecture and structural evolution of the SMO fold-thrust belt. We present a regional map that synthesizes our results from the hinterland to foreland of the SMO fold-thrust belt over a distance of 180 km. Our results ...
The Zagros thrust-and-fold belt is part of the Alpine-Himalayan orogenic belt. The general tectonic framework of the area is located between Qatar-Kazerun and Oman lines, southern of this active orogenic belt, is define by Zagros thrust system which is parallel to the belt and a series of ...
The Palmyride fold belt, a 400 {times} 100 km, NE-trending, transpressive belt in central Syria, represents the late Mesozoic and Cenozoic inversion of a linear intracratonic basin. The southwestern Palmyrides are characterized by short wavelength (2-5 km) folds separated by small intermontane basins. To elucidate ...
Naga fold thrust belt (NFTB), India, formed as a result of northward migration of the Indian plate initiated in Eocene and its subsequent collision with the Burmese plate during Oligocene. The NW-SE oriented compression generated a spectrum of structures; among them, we intend to focus on the folds- varying from gentle to tight ...
The Elk Basin anticline, Wyoming-Montana, has an order of magnitude more structural relief than structures of the Appalachian Plateau, New York. Despite its structural relief the Elk Basin anticline shows very little macroscopic evidence for layer-parallel shortening vs. more than 10% for the subtle Appalachian Plateau folds. Elk Basin anticline is a passive drape ...
