Download or read book Thermal History of the Susitna Glacier Thrust Fault Eastern Alaska Range written by Steven Riccio and published by . This book was released on 2012 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Topographically Asymmetrical Alaska Range written by Jeff Apple Benowitz and published by . This book was released on 2011 with total page 582 pages. Available in PDF, EPUB and Kindle. Book excerpt: The topographically segmented, ~700 km long Alaska Range evolved over the last ~50 Ma in response to both far-field driving mechanisms and near-field boundary conditions. The eastern Alaska Range follows the curve of the Denali Fault strike-slip system, forming a large arc of high topography across southern Alaska. The majority of the topography in the eastern Alaska Range lies north of the Fault. A region of low topography separates the eastern Alaska Range from the central Alaska Range, where most of the high topography lies south of the Denali Fault. To the west, there is a restraining bend in the Fault. Southwest of the bend, the north-south trending western Alaska Range takes an abrupt 90 degree turn away from the Denali Fault. I applied 40Ar/39Ar thermochronology to over forty granitic samples to constrain the thermal history of the western and eastern Alaska Range. I combine the 40Ar/39Ar analyses with available apatite fission track and apatite (U-Th)/He dating. I then inferred the Alaska Range's exhumation history from the region's rates and patterns of rock cooling. Periods of mountain building within the Alaska Range are related to Paleocene-Eocene ridge subduction and an associated slab window (~50 Ma to ~35 Ma), Neogene flat-slab subduction of the Yakutat microplate (~24 Ma to present), Yakutat microplate latitudinal variation in thickness (~6 Ma to present), block rotation/migration, and fault reorganization along the Denali Fault. However, it is clear from basin, petrological and thermochronological constraints that not all of the far-field driving mechanisms affected every segment of the Alaska Range to the same degree or at the same time. Alaska Range tectonic reconstruction is also complicated by near-field structural controls on both the timing and extent of deformation. Fault geometry affects both the amount of exhumation (e.g., ~14 km in the Susitna Glacier region of the eastern Alaska Range) and location of topographic development (e.g., north or south of the Denali Fault). The topographic signature we see today is also in part the result of a pre-existing landscape modified by Plio-Quaternary (~3 Ma to present) surface processes.
Download or read book Fission Track Thermochronology and its Application to Geology written by Marco G. Malusà and published by Springer. This book was released on 2018-07-14 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is focused on the basics of applying thermochronology to geological and tectonic problems, with the emphasis on fission-track thermochronology. It is conceived for relatively new practitioners to thermochronology, as well as scientists experienced in the various methods. The book is structured in two parts. Part I is devoted to the fundamentals of the fission-track method, to its integration with other geochronologic methods, and to the basic principles of statistics for fission-track dating and sedimentology applied to detrital thermochronology. Part I also includes the historical development of the technique and thoughts on future directions. Part II is devoted to the geological interpretation of the thermochronologic record. The thermal frame of reference and the different approaches for the interpretation of fission-track data within a geological framework of both basement and detrital studies are discussed in detail. Separate chapters demonstrate the application of fission-track thermochronology from various perspectives (e.g., tectonics, petrology, stratigraphy, hydrocarbon exploration, geomorphology), with other chapters on the application to basement rocks in orogens, passive continental margins and cratonic interiors, as well as various applications of detrital thermochronology.
Download or read book Sedimentary System Responses to External Forcings a Process Based Perspective written by Brian W. Romans and published by Frontiers Media SA. This book was released on 2020-12-01 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.
Download or read book The Denali Fault in the Canwell Glacier Area East Central Alaska Range written by John Raymond Kleist and published by . This book was released on 1971 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evolution of a Range boundary Thrust in a Strike slip Fault System written by Trevor Waldien and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The McCallum Creek thrust system consists of the McCallum Creek fault and a kinematically linked foreland blind thrust system that splay south from the Denali fault in the eastern Alaska Range. Apatite fission track cooling ages, tephrachronology, and balanced cross sections indicate that convergence partitioned to the McCallum Creek thrust system from the Denali fault has accommodated 3.3-3.6 km of rock exhumation resulting in 4.6-5.3 km of shortening directed toward ~005-185 since hanging wall samples passed through apatite fission track closure at ~6 Ma. Thrusting on the main McCallum Creek fault resulted in deposition of foreland strata in the footwall broadly coeval with apatite fission track cooling ages in the hanging wall of the fault. The blind foreland thrust system developed after ~3.7 Ma and was subsequently overtaken by out-of-sequence slip on the main McCallum Creek fault. Incised segments of modern streams and tilted Quaternary deposits suggest that foreland structures are the most recently active part of the thrust system. Shortening on the McCallum Creek fault results in internal contraction of the Southern Alaska Block and advocates for a combined rotational and indenter model for Southern Alaska Block motion. The onset of thrusting in the McCallum Creek area likely records a far-field response to plate-kinematic adjustments in the Alaska syntaxis at ~6 Ma.
Download or read book Tectono thermal History Modeling and Reservoir Simulation Study of the Nenana Basin Central Alaska written by Nilesh C. Dixit and published by . This book was released on 2017 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt: Central Interior Alaska is an active tectonic deformation zone highlighted by the complex interactions of active strike-slip fault systems with thrust faults and folds of the Alaska Range fold-and-thrust belt. This region includes the Nenana basin and the adjacent Tanana basin, both of which have significant Tertiary coal-bearing formations and are also promising areas (particularly the Nenana basin) with respect to hydrocarbon exploration and geologic carbon sequestration. I investigate the modern-day crustal architecture of the Nenana and Tanana basins using seismic reflection, aeromagnetic and gravity anomaly data and demonstrate that the basement of both basins shows strong crustal heterogeneity. The Nenana basin is a deep (up to 8 km), narrow transtensional pull-apart basin that is deforming along the left-lateral Minto Flats fault zone. The Tanana basin has a fundamentally different geometry and is a relatively shallow (up to 2 km) asymmetrical foreland basin with its southern, deeper side controlled by the northern foothills of the central Alaska Range. NE-trending strike-slip faults within the Tanana basin are interpreted as a zone of clockwise crustal block rotation. Seismic refection data, well data, fracture data and apatite fission track data further constrain the tectonic evolution and thermal history of the Nenana basin. The Nenana basin experienced four distinct tectonic phases since Late Paleocene time. The basin initiated as a narrow half-graben structure in Late Paleocene with accumulation of greater than 6000 feet of sediments. The basin was then uplifted, resulting in the removal of up to 5000 feet of Late Paleocene sediments in Eocene to Oligocene time. During Middle to Late Miocene time, left lateral strike-slip faulting was superimposed on the existing half-graben system. Transtensional deformation of the basin began in the Pliocene. At present, Miocene and older strata are exposed to temperatures > 60°C in the deeper parts of the Nenana basin. Coals have significant capacity for sequestering anthropogenic CO2 emissions and offer the benefit of enhanced coal bed methane production that can offset the costs associated with the sequestration processes. In order to do a preliminary assessment of the CO2 sequestration and coal bed methane production potential of the Nenana basin, I used available surface and subsurface data to build and simulate a reservoir model of subbituminous Healy Creek Formation coals. The petroleum exploration data were also used to estimate the state of subsurface stresses that are critical in modeling the orientation, distribution and flow behavior of natural coal fractures in the basin. The effect of uncertainties within major coal parameters on the total CO2 sequestration and coal bed methane capacity estimates were evaluated through a series of sensitivity analyses, experimental design methods and fluid flow simulations. Results suggest that the mature, unmineable Healy Creek Formation coals of the Nenana basin can sequester up to 0.41 TCF of CO2 while producing up to 0.36 TCF of CH4 at the end of 44-year forecast. However, these volumes are estimates and they are also sensitive to the well type, pattern and cap rock lithology. I used a similar workflow to evaluate the state of in situ stress in the northeastern North Slope province of Alaska. The results show two distinct stress regimes across the northeastern North Slope. The eastern Barrow Arch exhibits both strike-slip and normal stress regimes. Along the northeastern Brooks Range thrust front, an active thrust-fault regime is present at depths up to 6000 ft but changes to a strike-slip stress regime at depths greater than 6000 ft.
Download or read book Notes on Glaciers of South Eastern Alaska and Adjoining Territory written by Otto Julius 1852-1923 Klotz and published by Palala Press. This book was released on 2016-05-04 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Download or read book Cenozoic Tectono thermal History of the Southern Talkeetna Mountains Alaska written by Patrick J. Terhune and published by . This book was released on 2018 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intraplate mountain ranges can have polyphase topographic development histories reflecting diverse plate boundary conditions. We apply 40Ar/39Ar, apatite fission track (AFT) and apatite (U-Th)/He (AHe) geochronology-thermochronology to plutonic and volcanic rocks in the southern Talkeetna Mountains of Alaska to document regional magmatism, rock cooling and inferred exhumation patterns as proxies for the deformation history of this long-lived intraplate mountain range. High-temperature 40Ar/39Ar geochronology on muscovite, biotite and K-feldspar from Jurassic granitoids indicates post-emplacement (~158-125 Ma) cooling and Paleocene (~61 Ma) thermal resetting. 40Ar/39Ar whole rock volcanic ages and AFT cooling ages in the southern Talkeetna Mountains are predominantly Paleocene-Eocene, suggesting that the Range is partially paleotopography that formed during an earlier tectonic setting. Miocene AHe cooling ages within ~10 km of the Castle Mountain Fault suggest ~2-3 km of vertical displacement that also contributed to mountain building, likely in response to the inboard progression of the subducted Yakutat microplate. Paleocene-Eocene volcanic and exhumation ages across interior southern Alaska north of the Border Ranges Fault System are similar and show no N-S or W-E progressions, suggesting a broadly synchronous and widespread volcanic and exhumation event that conflicts with the proposed diachronous subduction of an active west-east sweeping spreading ridge beneath south-central Alaska. To reconcile this, we propose a new model for the Cenozoic tectonic evolution of southern Alaska. We infer that slab breakoff sub-parallel to the trench and subsequent mantle upwelling drove magmatism, exhumation and rock cooling synchronously across south-central Alaska and played a primary role in the development of the southern Talkeetna Mountains.
Download or read book Stratigraphy and Structural Geology of the Yanert Glacier Area East Central Alaska Range Alaska written by Theodore Francis Cota and published by . This book was released on 1975 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tectonic Growth of a Collisional Continental Margin written by Kenneth D. Ridgway and published by Geological Society of America. This book was released on 2007 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The convergent margin of southern Alaska is considered one of the type areas for understanding the growth of continental margins through collisional tectonic processes. Collisional processes that formed this margin were responsible for multiple episodes of sedimentary basin development, subduction complex growth, magmatism, and deformation. Two main collisional episodes shaped this Mesozoic-Cenozoic continental margin. The first event was the Mesozoic collision of the allochthonous Wrangellia composite terrane. This event represents the largest addition of juvenile crust to western North America in the past 100 m.y. The second event is the ongoing collision of the Yakutat terrane along the southeastern margin of Alaska. This Cenozoic event has produced the highest coast mountain range on Earth (Saint Elias Mountains), the Wrangell continental arc, and sedimentary basins throughout southern Alaska. Active collisional processes continue to shape the southern margin of Alaska, mainly through crustal shortening and strike-slip deformation, large-magnitude earthquakes, and rapid uplift and exhumation of mountain belts and high sedimentation rates in adjacent sedimentary basins. This volume contains 24 articles that integrate new geophysical and geologic data, including many field-based studies, to better link the sedimentary, structural, geochemical, and magmatic processes that are important for understanding the development of collisional continental margins."--Publisher's website.
Download or read book Active Tectonics and Seismic Potential of Alaska written by Jeffrey T. Freymueller and published by American Geophysical Union. This book was released on 2008-01-14 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This multi-disciplinary monograph provides the first modern integrative summary of the most spectacular active tectonic systems in North America. Encompassing seismology, tectonics, geology, and geodesy, it includes papers that summarize the state of knowledge, including background material for those unfamiliar with the region; address global hypotheses using data from Alaska; and test important global hypotheses using data from this region. It is organized around four major themes: subduction and great earthquakes at the Aleutian Arc; the transition from strike-slip to collision tectonics in the Yakutat Block accretion; the Denali fault and related structures and their role in accommodating permanent deformation of the overriding plate, and; regional integration and large-scale models, and the use of data from Alaska to address important global questions and hypotheses."--Cover description.
Download or read book Paleozoic to Neogene Stratigraphic and Structural History of the Alaska Range Suture Zone North of the Denali Fault East Central Alaska Range written by Casey Jean Huff and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cretaceous to Neogene significance and evolution of the ~2000 km long Denali fault, which extends from southern Alaska into the Yukon Territory, including its role in the development of the Alaska Range suture zone, is poorly understood. The Denali fault within the Alaska Range suture zone is addressed on two different timescales in this study. First, this study presents stratigraphic evidence for the evolution of the collision of the allocthonous Wrangellia composite terrane (WCT) into the margin of Mesozoic North America. The collision resulted in the formation Alaska Range suture zone in south-central Alaska. This study focused on the northern edge of the suture zone within the east central Alaska Range just north of the Denali fault. The stratigraphy of Devonian to Upper Cretaceous sedimentary strata are examined using U-Pb ages and Hf isotopic compositions on detrital zircons along with point counts on sandstones. The data show that a pre-collisional sandstone of the Devonian Yanert Fork assemblage has a maximum depositional age (MDA) of ~384 Ma and a strong affinity for the continental margin of North America. The Upper Jurassic-Lower Cretaceous east central Alaska Range Kahiltna assemblage (MDA ~145 Ma) is in a faulted, unconformable contact with the Devonian Yanert Fork formation. Hf isotopic data from this unit indicates sediment was sourced from both the WCT and Mesozoic North America. These data suggest that deposition from North America into the Kahiltna basin occurred 20 m.y. earlier than previous studies have suggested. The deposition of the transitional marine to non-marine Upper Cretaceous Panorama Peak unit (MDA ~84 Ma) indicates collision ended by the late Cretaceous. Second, this study examines the brittle structures accommodating the ~22 Ma to recent exhumation of the east central Alaska Range immediately north of the active, dextral-slip Denali fault. Using the graphical kinematic method on slickenlines in brittle fault zones from the region of youngest (~1 Ma apatite fission track age) exhumation and comparing it to the region of minor Neogene exhumation (~15 Ma apatite fission track age), this study shows that most faults in the region are NW-SE striking, moderately-to-steeply dipping normal faults and E-W striking dextral strike-slip faults. The fault plane solutions are compatible with right-lateral simple shear along the E-W striking right-lateral strike-slip Denali fault. The prevalence of these normal faults suggests that the youngest exhumation within the east central Alaska Range is accommodated at the surface by normal faults.
Download or read book Moletrack Scarps to Mountains written by Sean Patrick Bemis and published by . This book was released on 2010 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Deformation across plate boundaries often occurs over broad zones with relative motions between plates typically accommodated by faults of different styles acting together in a complex system. Collision of the Yakutat microplate within the Alaskan portion of the Pacific-North America plate boundary drives deformation over 600 km away where the Denali fault divides predominantly rigid crustal block motions of southern Alaska from distributed deformation in central Alaska. Quaternary geologic mapping along the Nenana River valley and the Japan Hills of the northern foothills of the Alaska Range defines zones of Quaternary thrust faulting recorded in the progressive deformation of Pleistocene fluvial terraces. I use topographic profiles of these terraces and paleoseismic trenching of fault scarps to characterize the Quaternary activity and constrain the subsurface geometry of these faults. Radiocarbon and cosmogenic exposure dating methods provide age control on the stratigraphy in the trenches and landforms offset by these faults. These observations define a 1-1.5 mm/yr slip rate for the Gold King fault which changes laterally from a north-vergent thrust into a north and south vergent thrust wedge that uplifts the Japan Hills. Along the Nenana River valley, the progressive deformation of Pleistocene surfaces defines a north-vergent critically-tapered thrust wedge. The geometry of progressive uplift and folding requires a near planar, south-dipping basal thrust fault with two major north-dipping backthrusts. All three faults were active simultaneously on a scale of 10 4 yrs with slip rates of 0.25-1 mm/yr, until the late Pleistocene when we infer the retreat of glacial ice from the main axis of the Alaska Range caused a change in thrust wedge dynamics. I use the orientation of Quaternary deformation north of the Denali fault to show that strain is highly partitioned and establish geologic constraints on the regional horizontal stress orientation. North of the Denali fault, fault-normal principal shortening accommodates 3-5 mm/yr of strain transfer across the Denali fault system. Two appendices contain additional results of paleoseismic trenching and neotectonic investigations across 4 active faults near the Nenana River. This dissertation includes previously unpublished co-authored material.
Download or read book Recent Glacial History of Gulkana and College Glaciers Central Alaska Range Alaska written by Richard D. Reger and published by . This book was released on 1964 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fission track Thermochronology and Its Application to Geology written by Marco G. Malusà and published by . This book was released on 2019 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is focused on the basics of applying thermochronology to geological and tectonic problems, with the emphasis on fission-track thermochronology. It is conceived for relatively new practitioners to thermochronology, as well as scientists experienced in the various methods. The book is structured in two parts. Part I is devoted to the fundamentals of the fission-track method, to its integration with other geochronologic methods, and to the basic principles of statistics for fission-track dating and sedimentology applied to detrital thermochronology. Part I also includes the historical development of the technique and thoughts on future directions. Part II is devoted to the geological interpretation of the thermochronologic record. The thermal frame of reference and the different approaches for the interpretation of fission-track data within a geological framework of both basement and detrital studies are discussed in detail. Separate chapters demonstrate the application of fission-track thermochronology from various perspectives (e.g., tectonics, petrology, stratigraphy, hydrocarbon exploration, geomorphology), with other chapters on the application to basement rocks in orogens, passive continental margins and cratonic interiors, as well as various applications of detrital thermochronology.
Download or read book Detrital thermochronology written by Matthias Bernet and published by Geological Society of America. This book was released on 2004-01-01 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
