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1
Crook, Stephen R. "Structural Geology of the Northern Part of Elkhorn Mountain, Bannock Range, Idaho." DigitalCommons@USU, 1985. https://digitalcommons.usu.edu/etd/6677.
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Northern Elkhorn Mountain was unmapped previous to this investigation. The mapped area is located north of Malad City, Idaho, in the Bannock Range. It is within the Basin and Range Province. The mapped area measures 5.4 mi. in the north-south direction and 8.9 mi. in the east-west direction.
The oldest exposed stratigraphic unit, within the mapped area, consists of orthoquartzite and is of Early Cambrian age. Cambrian formations of the mapped area, in ascending order, are as follows: Camelback Mountain Quartzite, Gibson Jack Formation, Elkhead Formation, Bloomington Formation, Nounan Formation, and St. Charles Formation. Units of Ordovician age are the Garden City and Swan Peak Formations. The youngest unit of Paleozoic age, found within the mapped area, is the Fish Haven-Laketown Formation of Ordovician-Silurian age. Rock types comprising the Paleozoic units are orthoquartzite, limestone, dolostone, and shale. Tertiary units present, within the area, are the Salt Lake Formation and volcanic rocks with the composition of andesite. These units occur only in isolated parts of the mapped area. Colluvial and alluvial deposits of Quaternary age are present in the valley west of Elkhorn Mountain and in the southeastern and northeastern parts of the mapped area.
Numerous high-angle normal faults dominate the structure of the area. They trend generally north and northwest. A major high-angle normal fault extends along the western side of Elkhorn Mountain and is responsible for the present topographic relief. Several small asymmetrical anticlines and a low-angle thrust fault are also present.
The structural features, within the area, resulted from two major periods of crustal deformation. The first event was the Laramide orogeny. Compressional forces, generated during this event, produced the anticlines and the thrust fault. Movement was eastward. The second event was Basin and Range faulting. It produced the high-angle normal faults. Basin and Range faultinq has been active from Oligocene to Holocene. The marginal normal fault, west of Elkhorn· Mountain, is probably active at the present time.
2
Green, George Meredith 1964 Carleton University Dissertation Geology. "Detailed sedimentology of the Bowser Lake group, northern Bowser basin, north-central British Columbia." Ottawa.:, 1992.
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3
Sigler, Joshua T. "The metamorphic and structural evolution of the Davis Peak area, northern Park Range, Colorado." Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1798480831&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Fitz-Gerald, Dudley Braden. "Evidence for an Archean Himalayan-style orogenic event in the northern Teton Range, Wyoming." Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1798480821&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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5
Valentino, David W. "Tectonics of the lower Susquehhanna River region, southeastern Pennsylvania and northern Maryland: late proterozoic rifting to late paleozoic dextral transpression." Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/30108.
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6
Huang, Kuan. "Geological studies of igneous rocks and their relationships along the Kyrenia Range, Northern Cyprus." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/b40204030.
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7
Venn, Jonathan Andrew. "Structural and metamorphic evolution of the northern Margin of the Pelvoux Hassif, Hautes Alpes, France." Thesis, University of Bristol, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358090.
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8
Nguyen, Phung T. "Structural geology and mineralization of the White Devil Mine, Tennant Creek, Northern Territory /." Title page, table of contents and abstract only, 1987. http://web4.library.adelaide.edu.au/thesis/09SB/09sbN576.pdf.
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9
Neves, Douglas Scott. "Footwall Deformation and Structural Analysis of the Footwall of the Willard Thrust Fault, Northern Wasatch Range, Utah." DigitalCommons@USU, 1989. https://digitalcommons.usu.edu/etd/5784.
Full textAbstract:
Deformation mechanisms in the footwall of the Willard thrust fault, northern Wasatch Range, Utah, change from dominantly plastic to dominantly cataclastic (both microscopically and macroscopically) in the Ophir Formation and Maxfield Limestone before the thrust begins to ramp laterally upsection southward, just to the north of the North Ogden Canyon field area. This transition in compressional deformation style and mechanism is located within a lateral distance of 3.2-kilometers along the 22-kilometer long trace of the thrust fault.
Between Willard Canyon and North Ogden Canyon penetrative deformation is localized within 200 meters of the thrust surface and is characterized by transposed bedding, solution cleavage parallel to bedding, a northeast- to northwest-dipping foliation, and tight isoclinal folds with axes plunging generally northward. A fracture overprint in the footwall is present throughout the study area. The transition in deformation mechanism and style suggests that footwall deformation is dependent on the sensitive response of limestone and shale to increased pressure and temperature conditions and also the presence of a lateral ramp in the footwall of the Willard thrust. Data from a hangingwall sequence diagram and a stratigraphic displacement diagram suggest the Taylor and Ogden thrusts formed prior to the Willard thrust (the roof thrust) and their sequential geometrical evolution may have been influenced by preexisting rifts in the underlying crystalline basement rock.
It is proposed that early Cretaceous movement of the Willard thrust sheet over the structurally lower and older Taylor and Ogden thrust sheets resulted in the formation of a recumbent syncline overturned to the east, a southward rising lateral ramp in the footwall of the Willard thrust, a lateral change in footwall deformation, and the anomalous east-west trending canyons that cut through the Willard thrust complex.
10
Zhao, Jian-xin. "The geology, geochemistry and geochronology of the Atnarpa Igneous Complex, SE Arunta Inlier, northern Australia : implications for early to middle proterozoic tectonism and crustal evolution." Title page, contents and abstract only, 1989. http://web4.library.adelaide.edu.au/theses/09SM/09smz63.pdf.
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Bendall, Betina. "Mid-Palaeozoic shear zones in the Strangways Range : a record of intracratonic tectonism in the Arunta Inlier, Central Australia." Title page, contents and introduction only, 2000. http://web4.library.adelaide.edu.au/theses/09PH/09phb458.pdf.
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12
Harbort, Terrence Anthony. "Structure and tectonic synthesis of the Marlborough block, Northern New England fold belt, Australia /." [St. Lucia, Qld.], 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19092.pdf.
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13
Harms, Tekla Ann, and Tekla Ann Harms. "STRUCTURAL AND TECTONIC ANALYSIS OF THE SYLVESTER ALLOCHTHON, NORTHERN BRITISH COLUMBIA: IMPLICATIONS FOR PALEOGEOGRAPHY AND ACCRETION." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/187539.
Full textAbstract:
In northern British Columbia, the Sylvester Allochthon of the Slide Mountain terrane is the most inboard of Cordilleran suspect terranes, resting as a vast klippe upon miogeoclinal strata of the Cassiar Platform. The Sylvester is oceanic; it comprises gabbro, pillowed and massive basalt, banded chert, carbonate, argillite, ultramafics and minor arenite, which range in age from Late Devonian to Late Triassic. Internal structure in the Sylvester Allochthon is characterized as a stack of innumerable interleaved tectonic slices, bounded by subhorizontal, layer-parallel faults. These lithotectonic units are an order of magnitude smaller than the terrane itself and may consist of only a single or a few repeated rock types. The internal structure of the Sylvester is complex but not chaotic; small numbers of slices occur together in larger second-order packages which are also fault-bounded and lensoidal. However, tectonic juxtaposition of unrelated lithologies and older-over-younger faults are common. The "stratigraphy" of the Sylvester assemblage is thus tectonic. Sliver-bounding faulting within the Sylvester is known to have, at least in part, predated its post-Triassic, pre-mid Cretaceous emplacement. The Sylvester was emplaced onto North America as the roof thrust to a foreland-style duplex within underlying North American strata. vii viii The Sylvester Allochthon is the most inboard of accreted terranes, however it does not represent a simple marginal basin. New microfossil dating demonstrates that most rock types occur through the complete range of Sylvester ages. Coeval but depositionally incompatable lithologies must have accumulated in separate ocean floor paleoenvironments. Lithologies of the allochthon derive almost exclusively from layer 1, only the surface of oceanic crust. Thus, Sylvester slices are telescoped remnants detached from a vast area of ocean crust which ranged in age and width through the upper Paleozoic but which is now otherwise entirely consumed. Similarities of rock type, internal structure, age range, and regional tectonic setting have identified the Sylvester Allochthon as broadly correlative with a discontinuous series of terranes extending the length of the Cordillera. Together, these terranes may represent the remnants of what was once the late Paleozoic proto-Pacific ocean floor.
14
Yeats, Kenneth James, and Kenneth James Yeats. "Geology and structure of the northern Dome Rock Mountains, La Paz County, Arizona." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/558016.
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Huang, Kuan, and 黃寬. "Geological studies of igneous rocks and their relationships along the Kyrenia Range, Northern Cyprus." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B40204030.
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Hines, Frederick Michael. "The sedimentation, tectonics and stratigraphy of the cretaceous/tertiary sequence of northwest Santander, northern Spain." Thesis, University of Oxford, 1986. http://ora.ox.ac.uk/objects/uuid:1d1f8c32-9fd3-44a5-ba6a-d963fa9868c0.
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The facies evolution of the Cretaceous/Tertiary sequence of NW Santander is considered in relation to the Cretaceous rifting and drifting, and Tertiary partial closure of the Bay of Biscay. Overlying the Palaeozoic basement are the fluvial Lower Triassic Buntersandstone and Upper Triassic Keuper evaporitic mudstone, deposited in a failed rift, extensional basin. Overlying Lower Jurassic carbonates are the syn-rift, continental elastics of the Vealden deposited in halfgrabens cut by transfer faults. The Vealden consists of two formations:- the lower, arenaceous-rich Barcena Mayor Fm. (braided stream environment) and the upper, argillaceous-rich Vega de Pas Fm. (meandering river). Overlying it is the Aptian Umbrera Fm. (calcarenite sheet), the Patrocinio Fm. (shoaling-up ward sandstone/marl alternation), the San Esteban Fm. (requienid/foraminiferal biomicrite of the internal platform) and the marls of the Rodezas Fm. The Upper Aptian Reocin Fm. is a requienid/foraminiferal biomicrite with thinned calcarenites deposited over active, diapiric palaeohighs. After initial marine and then equant calcite (meteoric phreatic) cementation, invasion of meteoric-derived groundwater over palaeohighs generated lenses of sucrosic dolomite in the Reocin Fm. Local mixing of further groundwater and Keuper-derived, sulphate-rich waters in karstic caverns precipitated sparry, baroque dolomite and Pb/Zn sulphides (by bacterial sulphate reduction). The clastic Lower Albian is a transgressive fluvial/estuarine/inner shelf sequence with tidal estuarine channels and sandwaves. The Middle/Upper Albian (syn-drift) has basal calcarenitic tidal sandwaves and is followed by storm/wave-reworked carbonates deposited on a homoclinal ramp. The clastic Lower Cenomanian is an estuarine/inner shelf deposit with tidal sandwaves and sandbars. The Middle/Upper Cenomanian is a storm/tide-dominated calcarenite. Outer shelf marls occur in the Turonian to Middle Campanian and the Upper Campanian to Middle Eocene is a sandy, foraminiferal inner shelf limestone. The Upper Eocene/Oligocene (syn-compression) is a carbonate slope-apron-reefal flysch deposit. It includes hemipelagic marl, neritic-derived calcarenitic turbidites and rudaceous mass flow deposits with highly polymict conglomerates. These were deposited coevally with Keuper piercement and thrust reactivation and date the Pyrenean compressional deformation here.
17
Kruse, Stefan. "Structural evolution of the northern Thor–Odin Culmination, Monashee Complex southern Canadian Cordillera." Thesis, University of New Brunswick, 2007. http://hdl.handle.net/1882/941.
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The Monashee Complex is a structural culmination which exposes rocks from the
lowest stratigraphic levels of the Canadian Cordillera. The Monashee Complex is
subdivided into two lesser structural culminations; the Frenchman Cap and Thor–Odin
culminations. The lithostratigraphic succession of the Thor–Odin Culmination is
completely transposed by penetrative isoclinal folds with amplitudes from microscopic
(<1 mm) to regional (10’s km). Lower structural levels are occupied by Proterozoic
gneisses and migmatites of the Monashee basement assemblage. These are infolded with
overlying metasedimentary rocks of the Monashee cover assemblage, which are
Proterozoic to possibly Paleozoic in age. The basement and cover assemblages were
subsequently intruded by Eocene granitic pegmatite, aplite and lamprophyre dykes.
Regional metamorphism of the basement and cover assemblages reached upper
amphibolite to lower granulite facies.
The northeastern portion of the Thor–Odin Culmination of the Monashee
Complex contains a suite of structures and fabrics, which are classified into four sets,
based on their interpreted kinematic significance. These are: 1) transposition related
structures (DT); 2) open, upright folds (DO); 3) exhumation related structures (DE); and 4)
brittle faults (DB). Each successive set of structures exerted a control on the geometry of
the next set. The large-scale geometry of the culmination is an interference structure
between DT folds, a DE arch and high-strain zones, and a DB brittle horst.
Early, DT fold style varies from intrafolial isoclinal “mature” style folds to
upright or inclined asymmetric “immature” folds. This continuum of fold styles, along
with evidence of anticlockwise rotation (looking down a vertical axis toward the shear plane) of fold axes and lineations is interpreted as being a result of penetrative triclinic
non-coaxial flow. DO upright, symmetrical folds overprint early structures and fabrics,
but are only preserved at low structural levels in the culmination where the DE coaxial
stretching overprint is weak. DE normal shear bands and boudins overprint all earlier
structures. A complex high-strain zone, the Thor–Odin High-Strain Zone, outcrops at
high structural levels and along the margins of the culmination. The Thor–Odin High-
Strain Zone developed as a result of material moving away from the crest of the
culmination, outwards toward the flanks.
Eocene brittle faults (DB) and fractures within the Thor–Odin Culmination of the
Monashee Complex are divisible into three distinct sets. Initial 340–010º trending strikeslip
faults (Set 1) were locally overprinted and reactivated by normal faults with a 325–
020º trend (Set 2). A third set of 255–275º trending fractures (Set 3) are interpreted as
conjugates to Set 1, reactivated as transfer faults to the Set 2 normal faults. Large
regional faults weather recessively forming topographic lineaments that transect the
Monashee Complex. The Victor Creek Fault defines one such lineament. Detailed
mapping within the northern Thor–Odin Culmination, reveals piercement points (fold
hinges) on the east side of the fault, which are not readily matched on the west side. The
minimum displacement required on the Victor Creek Fault to down-drop the fold hinge
below the level of exposure on the west side is 1370 m, assuming normal down-to-the
west displacement. However, the geometry of the fault is consistent with a Set 1 dextral
strike-slip fault. Matching the piercement points in the study area with possible
equivalents to the north indicates 55–60 kms of dextral strike-slip displacement.
The Monashee Reflection (MR) is a major crustal-scale, cross-cutting reflection
appearing on two mutually perpendicular Lithoprobe seismic profiles in the southern
Omineca Belt of the Canadian Cordillera. It has previously been interpreted as the downplunge
extension of an arched regional ductile thrust fault, the Monashee Décollement,
and is described as separating the Monashee Complex from the overlying Selkirk
Allochthon. Recent mapping demonstrates that this boundary is not a discrete ductile
thrust, but rather transposed and gradational. Overprinting the transition zone is a
complex, outward-dipping, normal, structure; the Thor−Odin High-Strain Zone.
Three alternative 3-D geometric models have been developed for the MR in order
to project the reflection to the surface. The favoured model correlates the surface trace of
the Thor−Odin High-Strain Zone with MR.
Normal shear sense kinematics are interpreted for the MR based on: 1) the
overall geometry and asymptotic relationship between the MR and reflections in the
hanging wall and footwall; 2) offset of metamorphic and geochronological gradients,
consistent with an extensional zone, rather than with thrust fault interpretation and 3) the
cross-cutting nature of the MR is consistent with normal structures throughout the region.
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Shunqukela, Tokozani. "A study of the structural geology of an area between the Neusspruit shear zone and the Brakfontein shear zone near Kakamas, Northern Cape." University of the Western Cape, 2014. http://hdl.handle.net/11394/4359.
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>Magister Scientiae - MSc<br>The study area Koekoeb B is a farm that falls under the Kakamas Terrane which in turn falls under the Gordonia Subprovince in the Namaqua-Natal Metamorphic Province, South Africa. This area was chosen due to lack in literature about its lithology. Koekoeb B is comprised of metasedimentary rocks of the Biesje Poort Subgroup and granitoids of the Keimoes Suite. The Kakamas Terrane was deposited in an intracratonic basin between the Kaapvaal Craton and the Namaqua continental mass. The sediments were buried with time and experienced metamorphism due to burial pressures and temperatures. The area experienced folding as a result of the collision of the newly formed Kakamas Terrane and the Bushmanland segment with the Kaapvaal Craton during a Wilson Cycle. During subduction and collision the metasedimentary rocks were intruded by what is known as the Keimoes Suite. The most abundant intrusive rock in Koekoeb B is the Friersdale Charnockite. It is considered the youngest with Rb-Sr ages around 1080-1090 Ma. The Gordonia Subprovince experienced such intense deformation that continuous folds formed and there is even evidence of parasitic folds. Northwest striking shear zones developed as a result of the continued compression of the Namaqua mass with the adjacent north easterly Kaapvaal Craton. The folds and shear zones formed under four major deformational events Two months were spent acquiring orientation data (direction of dip and dip) in the field. A Clar compass was used to measure the dip direction and dip readings of bedding, cleavage, joints and lineations. The orientation data was imported into Move® software to create a geological map. Samples collected from the field were used to produce thin sections for petrography studies using the petrographic microscope. Conclusions were drawn from the analysis of the data. Koekoeb B experienced regional metamorphism and folding when the Kakamas Terrane collided with the Kaapvaal Craton. The area was subdivided into four subareas based on the strike and dip data generated on the geological map. The synoptic β-axis diagram determined that the subareas are of the same generation but the fold axes orientations vary slightly. Because the study area did not include the shear zones no conclusive reason can be given but it can be assumed that the variation is due to movement along the shear zone or as a result of the intrusion of the Keimoes Suite. The area later experienced brittle deformation which is evident from the large number of joints found; the joints cut across the folds and show a different stress regime from the folds. Conjugate joints were observed on the field and plotted on stereonets. The results showed a vertical sigma two which confirmed that Koekoeb had been affected not only by compression tectonics but by the strike-slip movement on the shear zone.
19
Yuan, Tianson. "Seismic studies of the northern Cascadia accretionary prism, sediment consolidation and gas hydrates." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq21957.pdf.
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Loundagin, Nicholas R. "Geophysical Characterization of the Structural Configuration and Tectonic Evolution along the Northern Margin of the Gulf of Mexico Basin, Northwestern Mississippi." Thesis, University of Louisiana at Lafayette, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13422120.
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<p> The tectonic history of the Gulf of Mexico Basin in northwestern Mississippi is poorly understood due to a lack of publicly available data and overlying Mesozoic sediments. Using an extensive set of geophysical data including: well data, potential field data, and 2-D seismic data, we define distinct zones of varying structural styles across the region and provide new insight into the tectonic evolution of the northern margin of the Gulf of Mexico. </p><p> The cratonal region is defined by the extent of Precambrian basement across the region and is characterized by an orthogonal set of normal faults related to Precambrian – Cambrian rifting and subsidence along the southern Paleozoic shelf margin. The, now, foreland basin is composed primarily of Cambrian-Devonian shelf carbonates and Carboniferous clastics deposited along the southern continental margin, coinciding with the southern limit of Precambrian cratonal material. </p><p> Divisible into two structural domains, the Frontal and Allochthonous Domain, the sub-cropping Ouachita orogenic belt is defined by geophysical data in northwestern Mississippi. The Frontal Domain of the Ouachita zone is restricted to the western study area and is characterized by small, imbricate thrusts branching from a lower detachment within autochthonous sediments and an upper detachment along the base of back thrusted Carboniferous sediments. Large thrust sheets of the Allochthonous Domain are correlatable across the study area and are truncated to the north by large intrusions or basement blocks. </p><p> The seismically defined limit of the basinal zone corresponds to a linear gravity minima separating Mesozoic rift-related basins to the south from Precambrian and intrusive bodies to the north. Geophysical data of the basinal zone characterize multiple igneous bodies of varying ages. Syn-rift Triassic graben clastics confined to grabens paralleling the basinal zone limit are interpreted to be related to a Mesozoic rift-related transform across Mississippi separating rift basins of the larger region.</p><p>
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Al, Tarawneh Maha Atallah. "Structural setting of the Jordan Northern Highlands : an integrated study using surface and sub-surface geological data by utilizing GIS Technology." Doctoral thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/10001.
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This study was designed, for the identification of the General structural style of this part of Jordan by: (1) Definition of dominant structural styles in the JNH: such as the main structural elements, basins, and highs; (2) Inference of the structural setup and its tectonic significance, and (3) Identification of the influence of the Dead Sea Transform on the geological setting of the JNH area.
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Eagan, Keith E. "Paleoenvironmental and Stratigraphic Interpretation of the Middle Cambrian Ute Formation, Northern Utah." DigitalCommons@USU, 1996. https://digitalcommons.usu.edu/etd/6791.
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The Middle Cambrian Ute Formation includes some 200 m of cyclically alternating carbonates and mud rocks. These are arranged in eight to nine, meter-scale, shallowing-upwards packages, representing deposition under predominantly subtidal conditions. The packages consist of vertical sequences of shale, silty limestone, oncolitic packstone, and oolitic grainstone that exhibit little variance in this general pattern. Small-scale unconformities separate the packages. The inferred depositional environment consists of an intrashelf basin that has a peritidal platform near its margins. The craton, which supplied most of the terrigenous sediment, was situated to the south (Cambrian orientation), and located near the equator. One cycle includes a stromatolite biostrome that is distributed across more than 1500 km2 in northern Utah and southern Idaho. Stromatolites range from mound-like to club-shaped to columnar and reach up to 2 min vertical dimension, and 0.15 min diameter.
These large columnar structures were apparently established just basinward of an oolitic shoal. These ancient stromatolites, which are in many ways similar to those stromatolites recently reported from the Bahamas, contain many clues that suggest that they grew in normal marine conditions. These findings require a rethinking of the commonly held belief that Phanerozoic columnar stromatolites are indicators of restricted, hypersaline conditions. Analysis of several orders of laminae in Ute Formation stromatolites indicates periodicity in accumulation from which yearly accumulation rates may be inferred. Values obtained for growth rate range from 4.39-4.88 cm/yr. Such rates of accumulation are in accord with those documented for ancient stromatolites from the Bitter Springs Formation. Thus, even considering the occurrence of hiatal surfaces within the stromatolites, the duration of the columnar-stromatolite horizon probably encompasses 10-2 - 10-3 yr.
The biostrome's position in the sequence of cycles and the changes in stromatolite morphology across depositional dip suggest that the biostrome may be essentially isochronous across its outcrop area and, thus, may be viewed as a bioevent horizon. The stromatolites also contribute to a better understanding of the paleogeography of the study area during the Middle Cambrian by providing information on relative energy levels and flow directions. (212 pages)
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Moore-Nall, Anita Louise. "Structural controls and chemical characterization of brecciation and uranium vanadium mineralization in the Northern Bighorn Basin." Thesis, Montana State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10251316.
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<p> The goals of this research were to determine if the mode of mineralization and the geology of two abandoned uranium and vanadium mining districts that border the Crow Reservation might be a source for contaminants in the Bighorn River and a source of elevated uranium in home water wells on the Reservation. Surface and spring waters of the Crow Reservation have always been greatly respected by the Crow people, valued as a source of life and health and relied upon for drinking water. Upon learning that the Bighorn River has an EPA 303d impaired water listing due to elevated lead and mercury and that mercury has been detected in the fish from rivers of the Crow Reservation this study was implemented. Watersheds from both mining districts contribute to the Bighorn River that flows through the Crow Reservation.</p><p> Initial research used the National Uranium Resource Evaluation database to analyze available geochemistry for the study areas using GIS. The data showed elevated concentrations of lead in drainages related to the mining areas. The data also showed elevated uranium in many of the surface waters and wells that were tested as a part of the study on the Crow Reservation. The author attended meetings and presented results of the National Uranium Resource Evaluation data analyses to the Crow Environmental Health Steering Committee. Thus, both uranium and lead were added to the list of elements that were being tested in home water wells as part of a community based participatory research project addressing many issues of water quality on the Crow Reservation. Results from home wells tested on the reservation did show elevated uranium. </p><p> Rock samples were collected in the study areas and geochemically analyzed. The results of the analyses support a Permian Phosphoria Formation oil source of metals in the two mining districts. Structural data support fracturing accompanied by tectonic hydrothermal brecciation as a process that introduced oil and brines from the Bighorn Basin into the deposits where the uranium vanadium deposits later formed.</p>
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Robinson, Delores Marie, and Delores Marie Robinson. "Structural and neodymium-isotopic evidence for the tectonic evolution of the Himalayan fold-thrust belt, western Nepal and the northern Tibetan Plateau." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/289761.
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The Himalayan fold-thrust belt and Tibetan Plateau are the result of the collision between the Indian and Eurasian continents. This dissertation documents the kinematics and tectonic history of the Himalayan fold-thrust belt of western Nepal and the northern Tibetan Plateau. In the Himalayan fold-thrust belt, the Main Central thrust emplaced a hanging wall flat of Greater Himalayan rock over a footwall flat of Lesser Himalayan rock in Early Miocene time. Subsequent growth of the Lesser Himalayan duplex (LHD) uplifted and rotated the Ramgarh thrust sheet, Main Central thrust, and overlying Greater Himalayan rock to the surface. Thus, growth of the LHD is responsible for the northward dips in the Greater Himalaya. New Nd isotopic data from throughout Nepal indicate that Lesser Himalayan rocks consistently have more negative epsilonNd values than Greater and Tibetan Himalayan rocks. Growth of the LHD is documented in the syntectonic sediments of the Neogene Siwalik Group. At ∼10-11 Ma in central and western Nepal, the epsilonNd values of the Siwalik Group shift toward more negative values which indicate detrital input from rocks in the LHD. Regional mapping in western Nepal and three balanced cross sections provide a three-dimensional view of the fold-thrust belt. These cross sections suggest over 900 km of shortening in upper crustal rock from the Indus suture to the Main Frontal thrust. This suggests a corresponding ∼900 km long wedge of lower crustal rock was consumed by the Himalayan-Tibetan orogen. This wedge may have been inserted under the Tibetan Plateau, helping it obtain its anomalously thick crust. If lower crustal rocks have been inserted under the Tibetan Plateau, the Himalayan collision can account for ∼70% of the overthickened crust. This leaves ∼30% to be accounted for by other mechanisms. The Tula uplift documents shortening along the northern edge of the Tibetan Plateau. The lithic composition of its sandstone, deformation, and erosion of strata suggests that significant regional uplift and thickening occurred since Late Jurassic time and is still occurring. These relationships suggest that the northern Tibetan Plateau region was tectonically active, and undergoing shortening, long before the early Tertiary India-Eurasian collision.
25
Greenfield, John Edward. "Migmatite formation at Mt. Stafford, Central Australia." Phd thesis, Department of Geology and Geophysics, 1997. http://hdl.handle.net/2123/10592.
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Li, Hongyan. "Seismic calibration of northern Eurasia using regional phases from nuclear explosions and 3-D Moho configuration of accreted terranes in western British Columbia." Laramie, Wyo. : University of Wyoming, 2006. http://proquest.umi.com/pqdweb?did=1188873741&sid=3&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Delwiche, Benjamin M. "Oligocene paleotopography and structural evolution of the Pah Rah Range, western Nevada implications for constraining slip on the right-lateral Warm Springs Valley fault in the northern Walker Lane /." abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1446438.
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Winker, Charles David 1952. "Neogene stratigraphy of the Fish Creek-Vallecito section, southern California : implications for early history of the northern Gulf of California and Colorado Delta." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/191123.
Full textAbstract:
The Fish Creek-Vallecito section is the most stratigraphically complete and structurally intact Neogene exposure in the Salton Trough, and thus provides a useful reference section for regional stratigraphie revision and historical interpretation of the early Gulf of California and Colorado Delta. The section comprises a marine sequence (Imperial Formation) bracketed by nonmarine units (Split Mountain and Alverson Formations below, Palm Spring Formation and Canebrake Conglomerate above). Recognition of distinct suites of locally-derived and Colorado River-derived sediment, combined with sedimentological evidence, led to revision of this sequence in terms of informal members and geneticstratigraphic units: (1) pre-rift braided-stream deposits (2) syn-rift fanglomerates and volcanics, with local pre-marine evaporites; (3) pre-deltaic marine units, deposited primarily as small fan deltas; a progradational sequence of the ancestral Colorado delta, consisting of (4) an upward-shoaling marine sequence, and (5) a nonmarine deltaplain sequence; (6) lacustrine units; and (7) locally-derived basinmargin alluvium that interfingers with (4), (5) and (6). Neogene palinspastic base maps for paleogeographic mapping were based on displacement histories for the Pacific-North American plate boundary and its constituent faults. The tectonic-sedimentary history consists of: (1) early to middle Miocene rifting that propagated southward from southern California to the Gulf mouth; (2) northward marine transgression of the rift basin, reaching southern California by the late Miocene; (3) development of the San Andreas-Gulf of California transform boundary by inboard transfer of intraplate slip; (4) earliest Pliocene initiation of the lower Colorado River and Delta by rapid epeirogenic uplift of the Bouse Embayment; and (5) late Pliocene or Pleistocene transpressive uplift in the western Salton Trough caused by outboard transfer of slip from the San Andreas fault. The stratigraphic succession in the western Salton Trough resulted largely from tectonic transport through a series of paleoenvironments anchored to the North American plate by the entry point of the Colorado River.
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Kaenmee, Kwanjai. "Structural Interpretation and Investigation of the Displacement Gradients of the Normal Fault System beneath the Horda Platform, the northern North Sea." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for petroleumsteknologi og anvendt geofysikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19211.
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The North Sea basin is one of the best-studied areas in the world with respect to thestructural and sedimentary architecture of rift zones. The Base Cretaceous Unconformity,which defines a mappable horizon at the transition from synrift to postrift sequencesassociated with the Jurassic–Cretaceous rift, is well known as a reference marker for bothseismic and well log interpretations and covers most of the basin. This unconformity isinterpreted at the locations of the Øygarden Fault Zone, the Troll Fault Block, the NorthViking Graben, the Tampen Spur, the Snorre Fault Block, the Sogn Graben and the HordaPlatform. The complexities of the unconformity have been established and vary with thestructural and geographical position within the basin. However, as the Base CretaceousUnconformity covers most of the northern North Sea, its structural time map, is used to derivethe picture of post-structural framework of a rift basin and to locate essential structures in thedeeper sections.Three main reflectors (Pre-Jurassic 1, Pre-Jurassic 2 and Top seismic basement)located beneath the Base Cretaceous Unconformity on the Horda Platform, and have beeninterpreted using 2D seismic reflection data. These three reflectors have been studied in orderto investigate in detail the displacement gradients and possible linkage of the early faultsystem under the Horda Platform, and to evaluate their effect on the large-scale sedimentarchitecture. A main reason to work on the structures under the Horda Platform is due to thefact that these structures are believed to have existed already in the early stages of thenorthern North Sea basin development.The extensional normal fault systems of both the Permo-Triassic and the Late Jurassicrifts are considered a key control on the geological structures and sedimentary architecture ofthe region as presently seen. The basin evolution related Permo-Triassic rifting is mostpronounced on the eastern part of the Horda platform where its synrift geometry is obviouslyseen with the huge segment length and largest uplift explainable by a flexural stretchingmodel. The rift axis is transferred to position at base of the Viking graben during the Late-Jurassic rifting with the smaller magnitude of extension than the Permo-Triassic as clearlyseen by the less thickness of the synrift geometry. However, the structural evolution of normalfaults and the basin architecture under the Horda Platform is particularly affected by thecomplex interaction of fault linkage, fault propagation, fault growth, and death of faultthrough times from the early stage to the final stage of the basin development. Apart from theeffects of major tectonic controls, additionally, non-tectonic parameters, such as climate, seaor lake level changes, and differences in amount and type of sediment supply, should be takeninto account to influence the stratigraphic and sedimentation patterns in the basin.
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Ambrose, Tyler. "Structure, metamorphism, and tectonics of the northern Oman-UAE ophiolite and underlying metamorphic sole." Thesis, University of Oxford, 2017. http://ora.ox.ac.uk/objects/uuid:e9520624-0f91-4c9d-a9b9-e9e2fc5d5517.
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Ophiolites - thrust sheets of oceanic lithosphere that have been emplaced onto the continental margin - provide the opportunity to explore the structure and genesis of oceanic crust. As many ophiolites formed above subduction zones, they also allow for the investigation of mantle wedge and subduction interface processes. This the- sis examines the Oman-United Arab Emirates (UAE) ophiolite, which is the largest and most intensely studied ophiolite on Earth. Three distinct problems are addressed. (1) Recent research has proposed that the architecture and tectonic evolution of the ophiolite in the UAE differs from in Oman. In Chapter 2, I test this hypothesis by integrating new geological mapping and field observations with previously published maps of the ophiolite in the UAE. My results indicate that the ophiolite is gently folded, but otherwise largely intact. I demonstrate that the architecture of the ophi- olite in the UAE is not significantly different from in Oman. Thus, there is no basis for a different tectonic evolution as recently proposed. (2) Observations from exper- iments and small-scale natural shear zones indicate that volumetrically-minor phases can control strain localization. In Chapter 3, I test the hypothesis that minor phases control strain-localisation at plate boundaries. To do so, I analyzed peridotites from the base of the ophiolite, a palaeosubduction interface. My results demonstrate that minor phases limited olivine grain growth, which led to rheological weakening. (3) The mechanisms by which metamorphic soles detached from the downgoing slab and accreted to the hanging-wall mantle is unclear. In Chapter 4, I examine a transect across the metamorphic sole in the UAE. My results reveal that granulite formation was more extensive than is typically considered. I propose that granulite formation resulted in rheological strengthening, which caused the subduction interface to migrate into the downgoing slab and accrete the metamorphic sole.
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Yakovlev, Petr V. "Transitions in Structural Styles and Trends within the Northern Appalachian Hudson Valley Fold-Thrust Belt Near Catskill, New York." Thesis, Boston College, 2010. http://hdl.handle.net/2345/1191.
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Thesis advisor: Yvette D. Kuiper<br>The Hudson Valley fold-thrust belt (HVB) is a narrow belt of deformed Upper Ordovician to Middle Devonian clastic and carbonate strata exposed in the western Hudson Valley of New York State. Geologic mapping at a scale of 1:10,000 was carried out near the town of Catskill. The southern portion of the map area includes a large doubly-plunging structure which features a fault-dominated southern portion plunging towards 017° and a northern fold-dominated, 206° trending, southerly plunging segment. A relay structure between two major faults or fault systems is interpreted as existing between the two domains. Farther north, the HVB narrows and folds plunge shallowly towards 212°, and then widens with folds plunging shallowly towards 017°. The changes can be explained by a localized increase in slip on the Austin Glen Detachment in the center of the map area, and subsequent loss of slip towards the north<br>Thesis (BA) — Boston College, 2010<br>Submitted to: Boston College. College of Arts and Sciences<br>Discipline: College Honors Program<br>Discipline: Geology and Geophysics
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Whiting, Thomas H. "A study of the lithology and structure of the eastern Arunta Inlier based on aeromagnetic interpretation : a lithological subdivision and structural history of the eastern Arunta Inlier, with particular emphasis on the relationship between magnetic mineral petrogenesis, rock magnetism and aeromagnetic signature /." Title page, contents and abstract only, 1987. http://web4.library.adelaide.edu.au/theses/09PH/09phw6125.pdf.
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Boelema, Robert. "The metallogeny of the Upington and Kenhardt area, northern Cape." Thesis, Rhodes University, 1995. http://hdl.handle.net/10962/d1005587.
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In the Upington region, there are three major- tectonic crustal provinces; namely the Kaapvaal Craton, Kheis and Namaqua tectonic provinces. The Eburnian-aged (early Proterozoic) Kheis Province developed along the western flank of the Archaean Kaapvaal Craton while the Kibaran-aged (middle Proterozoic) Namaqua Metamorphic Province, superimposed on the Eburnian-aged basement, developed to the east of the Kheis Province. The Namaqua Metamorphic Province is divided into the Gordonia and Bushmanland Subprovinces, the former being further subdivided into various tectonostratigraphic terranes. These are termed, from west to east, the Kakamas, Areachap, and Upington Terranes. The Upington Terrane includes fault bounded grabens with accompanied bimodal volcanism and sedimentation of the Wilgenhoutsdrif and Koras Groups. The Areachap Terrane consists predominantly of amphibolites generated in an island arc environment while the Kakamas Terrane is characterised by volcano-sedimentary sequences which have been extensively intruded by syn to late-tectonic predominantly I-type Keimoes Suite granitoids. The main styles of mineralisation correlate well with the various tectonostratigraphic terranes. Sedimentary exhalative massive sulphide deposits are characteristic of the Bushmanland Subprovince and are thought to be associated with the deposits at Aggeneys and Putsberg to the west of the area under investigation. These deposits are considered to have been deposited in an east-west-elongated intracontinental basin. The Kakamas Terrane is typified by granite-related mineralisation. In the eastern portion of the Kakamas Terrane, Sn-Wand base metal-bearing veins occur while pegmatites are developed in the western portion. These two styles of granite-related mineralisation is considered to reflect differing depths of formation due mainly to varying degrees of thrusting. The Areachap Terrane consists of volcanogenic massive sulphide deposits of the Besshi-type and is considered to have formed in a back-arc environment. In the Upington Terrane, the Wilgenhoutsdrif and Koras Groups consists essentially of minor Cu occurrences mainly disseminated within basalts and in structural trap sites. The possibility for sediment-hosted Cu deposits is not ruled out. More recent surface processes have led to uranium and gypsum deposits in pans, river beds and calcretes. Eburnian aged tectonic setting remains enigmatic. Kibaran-aged tectonics which best fits the metallogeny of the area under investigation is considered to be of a subduction zone from west to east formed by the collision of the Bushmanland "microcontinent" against the Kaapvaal Craton. Subduction fbrmed an island arc setting in which the massive sulphide deposits were formed in the Areachap Terrane while the Wilgenhoutsdrif Groups developed in a marginal basin. Further convergence led to collision of the two continents and underriding of the Bushmanland "microcontinent" which generated predominantly I-type granitoids represented by the Keimoes Suite. The level of emplacement of these granitoids is a reflection of the degree of foreland thrusting and produced shallower level Sn-W and base metal vein-type mineralisation closer to the suture zone and deeper level pegmatites further from the suture zone to the west. The final period of deformation is represented by northward lateral movement which created "pull apart" fault-bounded basins into which the Koras Group was deposited.
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Wu, Kam-kuen, and 胡淦權. "Metamorphism of the Northern Liaoning Complex: implications for the tectonic evolution of the latearchean basement of the eastern block, North China Craton." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46935605.
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Nukman, Mochamad [Verfasser], Wilhelm [Akademischer Betreuer] Dominik, and Inga [Akademischer Betreuer] Moeck. "Geothermal exploration involving structural geology and hydrochemistry in the Tarutung Basin, Northern Central Sumatra (Indonesia) / Mochamad Nukman. Gutachter: Inga Moeck. Betreuer: Wilhelm Dominik." Berlin : Technische Universität Berlin, 2014. http://d-nb.info/1065669704/34.
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Hoffmann, Markus [Verfasser], and Anke M. [Akademischer Betreuer] Friedrich. "Young tectonic evolution of the Northern Alpine Foreland Basin, southern Germany, based on linking geomorphology and structural geology / Markus Hoffmann ; Betreuer: Anke Friedrich." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2017. http://d-nb.info/1139977849/34.
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Hoffmann, Markus Verfasser], and Anke M. [Akademischer Betreuer] [Friedrich. "Young tectonic evolution of the Northern Alpine Foreland Basin, southern Germany, based on linking geomorphology and structural geology / Markus Hoffmann ; Betreuer: Anke Friedrich." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2017. http://d-nb.info/1139977849/34.
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Hansen, Christel Dorothee. "The characterisation of an openwork block deposit, northern buttress, Vesleskarvet, Dronning Maud Land, Antarctica." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1013138.
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Investigating openwork block accumulation has the potential to further our understanding of rock weathering, the control of geological structure on landforms, the production of substrates for biological colonisation and the impacts of climate change on landform development and dynamics. Various models for the development of these landforms have been proposed. This includes in situ weathering, frost heave and wedging. Furthermore, it has been suggested that cold-based ice has the potential to preserve these features rather than to obliterate them. Blocky deposits are also frequently used as proxy evidence for interpreting palaeoclimates. The morphology and processes acting on a blockfield located on the Northern Buttress of the Vesleskarvet Nunataks, Dronning Maud Land, Antarctica (2°W, 71°S) were investigated and characterised. Given block dimensions and orientations that closely resembled the parent material and only small differences in aspect related characteristics observed, the blockfield was found to be autochthonous with in situ block production and of a young (Holocene) age. Small differences in rock hardness measurements suggest some form of aspect control on rock weathering. South-facing sides of clasts were found to be the least weathered. In comparison, consistently low rock hardness rebound values for the north-facing aspects suggest that these are the most weathered sides. Additional indicators of weathering, such as flaking and pitting, support analyses conducted for rock hardness rebound values. Solar radiation received, slope gradients and snow cover were found to influence weathering of clasts across the study site. Furthermore, ambient temperatures and wind speed significantly influenced near-surface ground temperatures dynamics. However, the lack of a matrix and paucity of fine material in textural analyses suggest a limited weathering environment. It is suggested that the retreat of the Antarctic ice sheet during the last LGM led to unloading of the surface, causing dilatation and subsequent fracturing of the bedrock along pre-existing joints, leading to in situ clast supply. Subsequent weathering and erosion along other points or lines of weakness then yielded fines and slight edge rounding of clasts.
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Morrison, William F. "Vertical and Lateral Hydraulic Connectivity of the Wilcox Formation for Tiber Field and the Outbound Structural Province of Keathley Canyon and Walker Ridge, Northern Gulf of Mexico." ScholarWorks@UNO, 2018. https://scholarworks.uno.edu/td/2569.
Full textAbstract:
Hydraulic connectivity for the Tiber field and 17 other Wilcox penetrations in Keathley Canyon (KC) and 5 fields in Walker Ridge (WR) protraction areas was assessed. All five chronostratigraphic Wilcox units are not in vertical communication across both protraction areas. Four of these units are in lateral communication across Tiber field except where faults isolate portions of the structure. Five “areas of connectivity,” where two or more fields are in communication, were found in KC. The fields in WR show no evidence of connectivity despite a relatively simpler structural environment than KC. I propose that the wells in WR are isolated due to a combination of diagenetic cementation and increased vertical effective stress acting to decrease permeability between structures. I also attempted to assess the possibility of hydrodynamic flow in the primary basin encompassing Tiber by geophysically identifying the field’s oil water contact and determining its orientation. This was unsuccessful.
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Rohrer, Lucas P. "BEDROCK GEOLOGIC MAPPING AND STRUCTURAL ANALYSIS OF THE WESTERN HALF OF THE PETERSHAM QUADRANGLE, CENTRAL MASSACHUSETTS: FURTHER TESTS OF THE MODEL FOR MIDDLE TO LATE PALEOZOIC DUCTILE TRANSPRESSION, VERTICAL EXTRUSION, AND LATERAL ESCAPE IN THE NORTHERN APPALACHIANS." UKnowledge, 2015. http://uknowledge.uky.edu/ees_etds/32.
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Bedrock mapping, structural analysis, and geochronology reveal the distribution of lithologies and timing of metamorphism and deformation in the western half of the Petersham 7.5’ quadrangle, western Massachusetts. Underlying lithologies are: (from west to east) the Ordovician Monson granitic orthogneiss, Silurian Rangeley migmatitic paragneiss, and Late Devonian (357 Ma) Hardwick tonalitic orthogneiss. Their tightly folded contacts strike north to south. The 361 Ma, unfoliated, strike-parallel Nichewaug quartz-diorite (10-100 m wide) intrusion spans the map area within the Rangeley. Evidence for vertical and lateral extrusion/escape of the Monson orthogneiss, as observed in the Palmer MA area, is absent. Instead, petrofabrics (foliations and lineations) indicate E-W shortening and N-S stretching concentrated within the Rangeley Fm. and orthogneiss margins. Asymmetric structures at the Rangeley-Hardwick contact indicate localized sinistral displacement parallel to unit boundaries and tectonic fabrics. U-Th-Pb chemical age dating of Rangeley monazite revealed three precise age populations (1 = 344 Ma; 3 = 377 Ma; 4 = 405 Ma) and one broad population divided into two subpopulations: 2b (~370 Ma) and 2a (~ 360 Ma). The similarity in age between tonalitic/dioritic magmatism and monazite growth in the Rangeley suggests regional metamorphism was driven by magmatic heat input from latest Devonian/earliest Carboniferous plutonism.
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Sonwa, Cyrille Stephane Tsakou. "Analysis of the structural geology of the high-grade metamorphic rocks in part of the Kakamas terrane of an area adjacent to the Neusspruit shear zone South of the orange river, Northern Cape, South Africa." University of the Western Cape, 2021. http://hdl.handle.net/11394/8257.
Full textAbstract:
>Magister Scientiae - MSc<br>The Proterozoic Namaqua-Natal Province comprises highly deformed rocks of medium to high grade metamorphism and is bordering the Archean Kaapvaal Craton to the west, south and east in South Africa. The sector to the west of the Craton, namely the Namaqua Sector, is structurally complex and subdivided from west to east into the Bushmanland Subprovince, the Kakamas and Areachap terranes of the Gordonia Subprovince and the Kheis Subprovince. The prominent Neusberg Mountain Range, with exposures to the north and south of the Orange River in the Kakamas Terrane constitutes evidence of crustal shortening as a result of continental collision of the Namaqua Sector block with the Kaapvaal Craton during the Namaquan Orogeny. The Mesoproterozoic Korannaland Group in the Kakamas Terrane is affected by faulting, folding and shearing.
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Holm, OH. "Structural and metamorphic evolution of the Arthur Lineament, northwestern Tasmania, Australia." Thesis, 2002. https://eprints.utas.edu.au/20519/7/whole_HolmOliverHakan2002.pdf.
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The aim ofthis project is to investigate the origin and deformational history ofthe Arthur
Lineament, using amulti-disciplinary approach. The field-based research concentrated on
the structural deformation ofthe study area. Laboratory-based research included
microstructural investigations, whole-rock geochemistry to investigate the mafic igneous
rocks in the study area, and metamorphic petrology and geochronology to characterise the
timing and nature ofthe metamorphic events that affected the lineament and surrounding
region.
TheArthur Lineament is a Cambrian age, high strain metamorphic belt located innorthwest
Tasmania, Australia. It is east-dipping, NE-trending, 5to 10 km wide and approximately
110 km long. The lineament consists ofphyllitic to schistose lithologies that have been
subject to medium- to high strain, and variably metamorphosed to blueschist, or greenschist
grade. The high strain belt comprises several different units. The major lithological unit in
the southern Arthur Lineament isthe Late Neoproterozoic "eastern" Ahrberg Group, which
comprises metamorphosed psammite and psammopelite units, transitional to tholeiitic
metabasalts and mafic volcanogenic metasediments. The southern Arthur Lineament also
contains the Bowry Formation, which contains basalt/dolerite-derived tholeiitic amphibolites
that are intruded by minor deformed 777±7 Ma granitoids, aunit correlated with the Ahrberg
Group (AGC) and Neoproterozoic high strain turhidite sequences (Bumie and Oonah
Formations).
Whole rock geochemistry ofthe metabasites in the "eastem" and "western" Ahrberg Groups,
the Bowry Formation and the AGC have been examined in order to enable an understanding
ofthe tectonic setting, into which the igneous rocks were emplaced. The "eastem" and
"western" Ahrberg Group sequences, and the AGC, are interpreted to be lithostratigraphic
correlates. The units have sequences oftransitional tholeiites, that are enriched relative to
MORB, and are increasingly tholeiitic towards the top ofthe stratigraphic pile. The Bowry
Formation also comprises transitional tholeiites, however they are more evolved than the
other units, and have REE pattems only slightly enriched relative to MORB.
The main orogeny to affect northwestem Tasmania was inthe Early to Middle Cambrian.
This event (the Tyennan Orogeny) consisted ofthree deformational episodes. The first two
episodes (CaD, and CaDz) were high strain events, related to arc-continent collision. These involved the emplacement of allochthonous slices, and the structuralrepetitionof units
within the lineament. CaDi produced isoclinalfolding, a schistose axial planar fabric and
shearingparallel to the CaFi axial plane. CaD2 wasmorepervasive than CaDi, and
produced tightto isoclinal folds with a schistose axial planarfabric. The CaSi and CaS2
axialplanar foliations are commonly sub-parallel, and the fold axesare close to parallel. The
orientation of CaFi and CaF2 folds changes from the low to high strain domains. In the low
strain domains, CaFi folds are variable in their orientation. CaF2 folds in the low strain
domains are gently east- and west-plunging, with south-dipping axial planes. In the high
strain domains, CaFi and CaF2 folds have east-southeastdipping axial planes, and southplunging
fold axes. This is consistent in both thenorth andthe southof the lineament.
Structural analysis suggests that the change in orientation is due to a strongly rotational shear
component during the CaD2 event, and thisisinterpreted as evidence forsouth-directed
transport.
The subsequent CaDs event, in the latest Cambrian, involvedeast-directed thrust. It
produced asymmetric folds with gentlywest-dipping longlimbsand steeply east-dipping
short limbs. The CaFs are gently south plunging, with gently west-dipping axial planes and
associated thrust faults. During the Devonian, and associated with extensive granitoid
intrusion, two episodes of open, east-west trending folding occurred.
Metamorphic investigations show that twometamorphic events occurred in the Arthur
Lineament. The earliest event corresponds to CaDi. This event has been pervasively
overprinted by the CaD2 event, whichhaslargely obliterated CaDi metamorphic textures.
Where observed, CaDi occurred at greenschistgradein allochthonous units. However in
units that are interpreted to be allochthonous, in theBowryFormation and withinpart of the
"eastern" Afrrberg Group, CaDi occurredat blueschist gradewith amphibole coresrecording
conditions of approximately 700-1000 MPa and 450-500°C. Syn-CaD2 metamorphism
varies across the Arthur Lineament. Early in the CaD2 event in the western parts of the
lineament, amphibole compositions indicate thatpressures were around500MPa, and the
metamorphic grade was in the upper greenschist facies. However in parts of the Bowry
Formation and the AGC, early CaD2 temperatures were around 460 ± 40°C, and pressures
were around 500-600 MPa. In these rocks, hornblende was stable in the metabasites, and
syn-CaD2 garnet, indicative of localised temperatures of approximately 500°C (greenschistamphibolitefacies
transition) were found. Duringlate CaD2, pressures were around300-400
MPa and the metamorphic grade was lower greenschist facies. Outside ofthe lineament,
metamorphic conditions duringCaDi and CaD2 didnot exceedgreenschist grade, with
temperatures of approximately 400°C and pressures of around 350 MPa. Metamorphic monazites in northwestern Tasmania andKingIslandwere investigated to
define the extent ofthe Cambrian deformation, and provide insight into other metamorphic
events. King Island has experienceda complexmetamorphic history. There is no evidence
ofthe Cambrian deformation, however a pronounced 1270 Ma regional metamorphic event,
contact metamorphism related to the 760 MaWickham Orogeny, and localised, mylonite
zone-related metamorphismat 380 Ma were observed. In the Arthur Lineament, the
dominantmetamorphic event occurredbetween510-540 Ma. Monazite growthin
metasedimentarysamples from within the lineament is attributed to the early-CaDa event.
However, awayfromthe lineament the Cambrian event is much weakerand significantly
older monazites of detrital origin, are common. No strong Devonian peak was observed.
In summary, in northwestem Tasmania, following theCambrian arc-continent collision, the
blueschistgrade (CaDi) allochthonous slices wereobducted and transported to the southof
the subductionzone, in a progressive deformational event. Other parautochthonous rocks
were also transported to the south duringthis high strainevent, with associated shearingand
folding occurring at greenschist grademetamorphic conditions. Sequential to this, a near
coaxial high straindeformational event took place, detaching other parautochthonous slices
that were variablymetamorphosed to greenschist andupper greenschist-amphibolite facies
(earlyCaD2), and overthrusting the different grade slices to the south. During these events,
strain-related rotation of the developingfolds took place, resulting in a change in orientation
ofthe fold axes from east-west to north south, and foliations from south-dipping to eastdipping,
from thelow strainzones into thehigh strain zones. The revised metamorphic
geochronology of the ArthurLineament indicates the earlyCaDi eventoccurred around 505-
510 Ma. DuringCaDx and early CaDj, the allochthonous and parautochthonous lithologies
were structurally emplacedon top of the less deformed, autochthonous units. In the final
stage of assembling the tectonostratigraphic 'pile', the various sliceswere stacked together,
and lower greenschist facies metamorphic conditions were developeduniformly in all
allochthonous, parautochthonous and autochthonous blocks(late CaD2). Subsequent to this,
the CaDs event caused the tilting ofthe tectonostratigraphy, to complete the evolution of the
Arthur Lineament.
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Pogue, Kevin R. "Stratigraphic and structural framework of Himalayan foothills, northern Pakistan." Thesis, 1993. http://hdl.handle.net/1957/35578.
Full textAbstract:
The oldest sedimentary and metasedimentary rocks exposed
in the Himalayan foothills of Pakistan record a gradual transition
seaward from the evaporites of the Salt Range Formation to pelitic
sediments deposited in deeper water to the north. The Upper
Proterozoic Tanawal Formation was derived from erosion of a
northern highland produced during the early stages of Late
Proterozoic to early Ordovician tectonism. Early Paleozoic tectonism
is indicated by an angular unconformity at the base of the Paleozoic
section, the intrusion of the Mansehra Granite, and the local
removal of Cambrian strata. Paleozoic shallow-marine strata are
preserved in half-grabens created during extensional tectonism
that began during the Carboniferous and climaxed with rifting
during the Permian. Paleozoic rocks were largely or completely
eroded from northwest-trending highlands on the landward side of
the rift shoulder. Thermal subsidence of the rifted margin resulted
in transgression of the highlands and deposition of a Mesozoic
section dominated by carbonates. Compressional tectonism related
to the impending collision with Asia commenced in the Late
Cretaceous. Rocks north of the Panjal-Khairabad fault were
deformed and metamorphosed during Eocene subduction of
northern India beneath the Kohistan arc terrane. Following their
uplift and exhumation, rocks metamorphosed beneath Kohistan
were thrust southward over unmetamorphosed rocks along the
Panjal and Khairabad faults which are inferred to be connected
beneath alluvium of the Haripur basin. Contrasts in stratigraphy
and metamorphism on either side of the Panjal-Khairabad fault
indicate that shortening on this structure exceeds that of any other
fault in the foothills region. The migration of deformation towards
the foreland produced south- or southeast-vergent folds and thrust
faults in strata south of the Panjal-Khairabad fault and reactivated
Late Cretaceous structures such as the Hissartang fault. The
Hissartang fault is the westward continuation of the Nathia Gali
fault, a major structure that thrusts Proterozoic rocks in the axis of
a Late Paleozoic rift highland southward over Mesozoic strata.
Fundamental differences in stratigraphy, metamorphism, and
relative displacement preclude straightforward correlation of faults
and tectonic subdivisions of the central Himalaya of India and
Nepal with the northwestern Himalaya of Pakistan.<br>Graduation date: 1994
44
Chernicoff, Carlos Jorge. "Synthesis of the structural geology of the Northern Transvaal." Thesis, 2014. http://hdl.handle.net/10210/10229.
Full textAbstract:
M.Sc. (Geology)<br>The study area is subdivided into seven tectonic domains, viz. Bandelierkop, Southern Beit Bridge Complex, Alldays, Hestern Transvaal, Soutpansberg, Waterberg and Lebombo domains. The Bandelierkop domain comprises the Southern Marginal Zone of the Limpopo Belt (Bdl) and the northern portion of the Kaapvaal craton (Bd2). Bdl is characterized by the presence of highly disrupted xenoliths of pelitic and mafic supracrustal rocks distributed in a "s ea " of granitic ·material. This contrasts with the much bigger supracrustal xenoliths in Bd2, i.e. the greenstone belt relicts. The granulite facies rocks of Bdl may have been upthrust roughly from south to north along one or more south-dipping thrust faults soling into a gently-dipping to flatlying basal shear zone. Since this model reveals the existence of the Kaapvaal craton partly on edge, the progressively higher grade of regional metamorphism (from greenschist to granulite facies) encountered in the Bandelierkop domain, from south (Bd2) to north (Bdl), could express the transition from upper crust to lower crust as exposed on the present land surface. The structural trends found in Bdl and Bd2 are not strictly confined to either area, and some overlapping exists. The most distinct structural trend in Bdl is a west-northwest fold trend, a northeast fold trend also being recognized in the eastern portion of Bdl. Bd2 exhibits f~ld trends varying from west-northwest to northeast in orientation; in this area there is ample evidence for the later nature of the northwest- to west-northwest oriented folding event. The east-northeast- to northeast folding is con~ dered to represent an event independent of the effect of deformation of the Kudus River shear zone to which this folding was previously thought to be related.The portion of the Central Zone of the Limpopo Belt falling within South African territory comprises the Alldays and Southern Beit Br_idge Compl ex (SBBCd) doma tn s., There exists a marked contrast between the roughly north trending fold trends of the Alldays domain and the east-northeast fold structure of the southernmost part of the Central Zone, the SBBCd. The relatively gentle plunges of the fold structure of the Alldays domain may have accentuated the size of the regional folds in this region. The SBBCd occupies a narrow east-northeast oriented strip extending immediately south of the Alldays domain, where tightly folded gneisses and metasedim~nts are exposed. all strata are strongly aligned in the regionally extensive eastnortheast direction. A contrasting difference between the SBBCd and the surrounding Precambrian terranes is clear, as the former domain conveys a relatively higher strain; this evidence of heterogeneous strain suggests that the SBBCd represents a shear zone. The shearing movement may have been of thrust type, consistent with the thrust model referred to above, and the SBBCd may be regarded as the thrust plane. In'iiew of the steeply-dipping, south-southwest oriented fold axes known to exist along part of the SBBCd (area south of Messina), it would appear that, at least in that area, the thrust movement would have been towards the north-northeast. A late, involved history of deformation followed in the SBBCd, during which one or more episodes of wrench-type movement may have taken place. The Soutpansberg domain is a relatively narrow and long fault zone of Proterozoic to Phanerozoic age that separates 'mobile belt' environment to the north, from 'cratonic' environment to the south. A linked fault system characterized by south-dipping, normal listric faults soling into ? gently-dipping major detachment surface may account for the structural pattern of this domain. The thrust system referred to above, which developed earlier in the geological history of the region along the Limpopo Belt - Kaapvaal craton boundary, may have controlled the late extensional displacement in the Soutpansberg domain. The overall structure of the Waterberg domain would seem to be controlled by the superimposition of northeastand northwest oriented gentle folds and, with the exception of locally intense deformation in the early Waterberg basin, would appear to have developed on a relatively stable portion of crust. The structure of the Lebombo domain is characterized by a north-south striking monocline with gentle east dip. Most of the lineaments inferred from the aeromagnetic survey of the study area originate from dyke intrusions. Faulting, fracturing and shearing are less clearly manifested in the pattern of the aeromagnetic contour maps, instead they are better correlated with the lineaments inferre~ from LANDSAT imagery and from the drainage patterns of the region.
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Van, Heeswijck Aldo. "The structure, sedimentology, sequence stratigraphy and tectonics of the northern Drummond and Galilee Basins, Central Queensland, Australia." Thesis, 2006. https://researchonline.jcu.edu.au/1557/1/01front.pdf.
Full textAbstract:
The Late Devonian-Early Carboniferous Drummond Basin and overlying Late Carboniferous-Middle Triassic Galilee Basin are extensive intracratonic basins with predominantly fluvial sediment infill. They are inferred to have developed on Proterozoic and Early Palaeozoic basement similar to the adjacent Charters Towers Province and Anakie Inlier. Depositional and structural architecture of the basins have been investigated through a combination of seismic, geophysical well log and gravity data sets with lithologic information obtain from well cores, surface mapping and sedimentary petrography.
Comprehensive interpretation of 750 km of seismic traverse resulted in the recognition of eleven seismic facies, several of which have distinctive internal signatures, separated by reflection boundaries that can be traced basin wide. Lithologic and geophysical logs from sixteen wells and boreholes can be matched to seismic stratigraphic units and allow the basinal infill to be described in terms of the lithostratigraphic frameworks already established in the literature. The construction of structure contours for unit boundary surfaces has identified extensional structures associated with rift phases of basinal development and the pattern of thrust and thrust fold features associated with basin inversion. Eleven new structural features that have continuity through the Drummond and Galilee Basins have been defined and other features noted in the literature have been reinterpreted based on evidence from seismic profiles. The construction of isopachs for each unit has allowed tracking of basinal infill thickness trends through time.
Analysis of geophysical and lithologic logs from petroleum wells and boreholes, augmented by sections documented from surface exposure has resulted in the recognition of some 16 discrete sequences, each based on a repeating pattern of three types of non-marine systems tract that mainly reflect basinal tectonics but also the influence of climate and eustatic sea level change. Both basins share a common style of sequence development that is not reflected in the current literature.
Provenance interpretation based on petrographic data from 121 thin sections representative of most of the Drummond Basin and all of the Galilee Basin suggests that the majority of basin infill was derived from a recycled cratonic source, such as the Thomson Fold Bel to the west, and less material derived from an eastern volcanic arc than previously thought. However SHRIMP-derived U-Pb age data for zircon populations from two samples broadly representative of quartz arenites prominent in the basinal successions conflict with this view. Such data for a sample from the Mount Hall Formation of the Drummond Basin indicates that its source was largely from Early to Mid Palaeozoic igneous terranes like those represented in the Charters Towers Province to the north and inferred for the Thomson Fold Belt to the west. Zircon ages of a sample of Warang Sandstone of the Galilee Basin indicates a Late Palaeozoic igneous source, with derivation largely from an eastern magmatic arc.
The Drummond Basin commenced as a back-arc extensional basin, progressed through a thermal sag phase and ceased development during mild compression associated with a far-field expression of the Kanimblan Orogeny. Structural patterns show initial rift architecture, with compartments separated by newly defined transfer fault zones. Extensional faults between the transfer structures extend further through the basinal succession than previously thought. This basin developed a broad sag phase but the final stages show a foreland influence induced by Kanimblan thrust loading on its eastern margin. Basinal structure has been strongly modified by inversion in the Middle Triassic associated with the Hunter-Bowen Orogeny.
The Galilee Basin commenced as a foreland basin expressing continuity with the late-stage development of the underlying Drummond Basin from which its division is arbitrary and based on historical misconceptions of Kanimblan tectonism. Thermal subsidence related to the rift phase of the Drummond Basin continued as an influence in addition to foreland subsidence. Tectonic quiescence marks a mid-stage of basinal development reflected in a regionally developed paraconformity and deposition of a basinwide coal measure sequence related to eustatic sea level rise over a stable substrate. The upper part of Galilee Basin infill reflects a foreland phase of development and records two episodes of thrust loading on the eastern margin associated with the Hunter-Bowen Orogeny.
Ongoing crustal contraction during the Hunter-Bowen Orogeny resulted in inversion of the Drummond and Galilee Basins with the development of large-scale thrust dislocations and associated fault bend anticlinal structures. The Middle Triassic Clematis Group is the youngest unit that shows folding due to inversion. Much of the western parts of both basins remain relatively undisturbed apart from gentle regional pre-Middle Jurassic tilting that marked the final phase of Hunter-Bowen tectonism.
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Van, Heeswijck Aldo. "The structure, sedimentology, sequence stratigraphy and tectonics of the northern Drummond and Galilee Basins, Central Queensland, Australia." 2006. http://eprints.jcu.edu.au/1557/1/01front.pdf.
Full textAbstract:
The Late Devonian-Early Carboniferous Drummond Basin and overlying Late Carboniferous-Middle Triassic Galilee Basin are extensive intracratonic basins with predominantly fluvial sediment infill. They are inferred to have developed on Proterozoic and Early Palaeozoic basement similar to the adjacent Charters Towers Province and Anakie Inlier. Depositional and structural architecture of the basins have been investigated through a combination of seismic, geophysical well log and gravity data sets with lithologic information obtain from well cores, surface mapping and sedimentary petrography. Comprehensive interpretation of 750 km of seismic traverse resulted in the recognition of eleven seismic facies, several of which have distinctive internal signatures, separated by reflection boundaries that can be traced basin wide. Lithologic and geophysical logs from sixteen wells and boreholes can be matched to seismic stratigraphic units and allow the basinal infill to be described in terms of the lithostratigraphic frameworks already established in the literature. The construction of structure contours for unit boundary surfaces has identified extensional structures associated with rift phases of basinal development and the pattern of thrust and thrust fold features associated with basin inversion. Eleven new structural features that have continuity through the Drummond and Galilee Basins have been defined and other features noted in the literature have been reinterpreted based on evidence from seismic profiles. The construction of isopachs for each unit has allowed tracking of basinal infill thickness trends through time. Analysis of geophysical and lithologic logs from petroleum wells and boreholes, augmented by sections documented from surface exposure has resulted in the recognition of some 16 discrete sequences, each based on a repeating pattern of three types of non-marine systems tract that mainly reflect basinal tectonics but also the influence of climate and eustatic sea level change. Both basins share a common style of sequence development that is not reflected in the current literature. Provenance interpretation based on petrographic data from 121 thin sections representative of most of the Drummond Basin and all of the Galilee Basin suggests that the majority of basin infill was derived from a recycled cratonic source, such as the Thomson Fold Bel to the west, and less material derived from an eastern volcanic arc than previously thought. However SHRIMP-derived U-Pb age data for zircon populations from two samples broadly representative of quartz arenites prominent in the basinal successions conflict with this view. Such data for a sample from the Mount Hall Formation of the Drummond Basin indicates that its source was largely from Early to Mid Palaeozoic igneous terranes like those represented in the Charters Towers Province to the north and inferred for the Thomson Fold Belt to the west. Zircon ages of a sample of Warang Sandstone of the Galilee Basin indicates a Late Palaeozoic igneous source, with derivation largely from an eastern magmatic arc. The Drummond Basin commenced as a back-arc extensional basin, progressed through a thermal sag phase and ceased development during mild compression associated with a far-field expression of the Kanimblan Orogeny. Structural patterns show initial rift architecture, with compartments separated by newly defined transfer fault zones. Extensional faults between the transfer structures extend further through the basinal succession than previously thought. This basin developed a broad sag phase but the final stages show a foreland influence induced by Kanimblan thrust loading on its eastern margin. Basinal structure has been strongly modified by inversion in the Middle Triassic associated with the Hunter-Bowen Orogeny. The Galilee Basin commenced as a foreland basin expressing continuity with the late-stage development of the underlying Drummond Basin from which its division is arbitrary and based on historical misconceptions of Kanimblan tectonism. Thermal subsidence related to the rift phase of the Drummond Basin continued as an influence in addition to foreland subsidence. Tectonic quiescence marks a mid-stage of basinal development reflected in a regionally developed paraconformity and deposition of a basinwide coal measure sequence related to eustatic sea level rise over a stable substrate. The upper part of Galilee Basin infill reflects a foreland phase of development and records two episodes of thrust loading on the eastern margin associated with the Hunter-Bowen Orogeny. Ongoing crustal contraction during the Hunter-Bowen Orogeny resulted in inversion of the Drummond and Galilee Basins with the development of large-scale thrust dislocations and associated fault bend anticlinal structures. The Middle Triassic Clematis Group is the youngest unit that shows folding due to inversion. Much of the western parts of both basins remain relatively undisturbed apart from gentle regional pre-Middle Jurassic tilting that marked the final phase of Hunter-Bowen tectonism.
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Jones, James V. Connelly James N. "Proterozoic tectonic evolution of southern Laurentia new constraints from field studies and geochronology in southern Colorado and northern New Mexico, U.S.A. /." 2005. http://repositories.lib.utexas.edu/bitstream/handle/2152/1945/jonesiiij96843.pdf.
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Rogers, Robert Douglas Mann Paul. "Jurassic-recent tectonic and stratigraphic history of the Chortis block of Honduras and Nicaragua (northern Central America)." 2003. http://wwwlib.umi.com/cr/utexas/fullcit?p3122784.
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Davies, Richard Charles Idris. "Tectonic, magmatic and metallogenic evolution of the Cajamarca mining district, Northern Peru." Thesis, 2002. https://researchonline.jcu.edu.au/10/1/01front.pdf.
Full textAbstract:
In the Cajamarca region of northern Peru periods of peak Tertiary magmatism
had a close association with orogenic episodes and high plate convergence rates. New
40Ar/39Ar dates show magmatism in the region had commenced by late Palaeocene
times, some 15 m.y. earlier than suggested by previous geochronological studies.
Palaeogene (57-43 Ma) intrusive and volcanic rocks are intermediate in composition
with flat REE profiles and primitive isotope compositions. These magmas were derived
from an immature sub-Andean mantle dominated by pyroxene and olivine. This
magmatic interval coincided with development of an early fold-thrust fabric in
deformed sedimentary rocks.
Early Miocene onset of high plate convergence rates triggered the generation of
oxidised hydrous melts from the breakdown of a sub-Andean amphibole-rich upper
mantle to lower crust. These melts rose into large magma ponds deep within the crust.
Sr, Nd and Pb isotope compositions indicate synmineralisation magmas and metals
were derived from a common deep source and that magmas underwent minimal upper
crustal contamination. During brief changes in the tectonic stress, primitive hydrousrich
magmas were released from these chambers and ascended rapidly along deeply
tapping faults. Dioritic intrusions with HREE-depleted profiles were emplaced during
periods of extension in a highly fractured upper crust. New 40Ar/39Ar dates indicate this
occurred from 23.2 to 16.5 Ma. Mineralised stocks are commonly located in the
hanging wall of a regional thrust fault and situated at structural intersections, such as
oblique secondary structures superimposed on pre-existing regional-scale faults.
Mineralisation-controlling structures, e.g. fault, vein and fracture arrays, at the porphyry
deposits have subparallel NNW and NE-NNE trends that suggest they were directly
controlled by a regionally extensive stress regime. The physiochemical conditions that
prevailed during early stage hypogene mineralisation strongly influenced the Au
enrichment at the various porphyry deposits. Au-rich deposits are typically hosted in
carbonates, tend to have well-developed potassic alteration zones, high temperature and
oxygen fugacity hypogene sulphide mineral assemblages (bornite + chalcopyrite) and
abundant hydrothermal magnetite. In contrast, mineralised stocks in contact with
fractured quartzites ± carbonates are Cu-Au-Mo deposits with lower temperature hypogene sulphide assemblages of chalcopyrite and pyrite, and potassic alteration zones
overprinted by low-grade pyritic phyllic alteration.
Late Miocene high-sulphidation deposits (~11 Ma) near Cajamarca formed
during the cessation of intense crustal thickening and uplift that was associated with
shallowing of the slab dip angle. Location of ore bodies at the Yanacocha mine was
largely controlled by WNW structures, indicating rotation of the dominant fault
orientation from NNE-NNW to WNW with time. A mineralised dioritic-tonalitic
intrusion beneath the Yanacocha high-sulphidation system has a steep HREE-depleted
profile and more evolved radiogenic Sr-Nd isotope compositions than the early Miocene
intrusions. However, a pyrite Pb isotope composition from this intrusion is significantly
less radiogenic than sulphides from early Miocene deposits. These features indicate late
Miocene magmas were formed beneath a thickened crust, similar to that at the present
day, and require a higher garnet content in the source.
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Davies, Richard Charles Idris. "Tectonic, magmatic and metallogenic evolution of the Cajamarca mining district, Northern Peru /." 2002. http://eprints.jcu.edu.au/10.
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