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Book Sedimentology Structural Geology and Paleomagnetism of the Ghost Rocks Formation Kodiak Islands Alaska

Download or read book Sedimentology Structural Geology and Paleomagnetism of the Ghost Rocks Formation Kodiak Islands Alaska written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Twenty-two hundred kilometers of Alaskan coastline, from Sanak to Baranof Islands, contains evidence of a Cretaceous to Eocene trench-ridge-trench (TRT) triple junction. Due to the long-term presence of inboard right-lateral strike-slip faults, the original location of the TRT triple junction with respect to North America is unknown. Previous paleomagnetic studies of the Ghost Rocks Formation of the Kodiak Islands, AK indicate a Latest Cretaceous to Early Paleocene TRT triple junction location of ~42 degrees north latitude (Plumley et al., 1983). However, this data set has proved controversial in the literature due to discordant site mean directions between the two major bays studied (Alitak and Kiliuda) as well as a 2-stage structural correction in Alitak Bay and possible remagnitization (e.g. Haeussler et al., (2003a). This study presents new sedimentologic, structural geologic, and preliminary paleomagnetic data in an attempt to resolve the location of TRT the triple junction. The Ghost Rocks Formation is part of an accretionary complex which contains turbidites interlayered with pillow lavas and intruded by gabbro and mafic sills. New structural geologic mapping of the Ghost Rocks Formation shows a mean bedding strike of ~250 degrees, and small-scale block rotations in Alitak Bay. Oriented samples across the formation were taken to include a baked contact test, conglomerate test, and fold test to ensure reliable data. 14 sites from Alitak Bay have been fully analyzed, and 12 sites have been partially analyzed. Second-removed magnetic components represent primary magnetization, and 13 sites showed reliable demagnetization behavior and bedding measurements. In-situ site mean direction for these 13 sites (D=349, I=-45, n=13, k=4.3, [alpha]95=22.8) is improved when corrected for local stratigraphy and structural block rotations (D=178, I=-63, n=13, k=29.2, [alpha]95=7.8). These results are in partial agreement with the original data, and show an improved agreement between the original Kiliuda Bay and the new Alitak Bay declination directions. Continued study of remaining sites will further constrain the data.

Book Geology of the Alaska Peninsula Island Arc and Continental Margin Part 1

Download or read book Geology of the Alaska Peninsula Island Arc and Continental Margin Part 1 written by C.A. Burk and published by Geological Society of America. This book was released on 1965 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Detrital Zircon Dating of the Kodiak Accretionary Complex South Alaska

Download or read book Detrital Zircon Dating of the Kodiak Accretionary Complex South Alaska written by Amirsasan Mahjoor and published by . This book was released on 2011 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: Southern Alaska crustal exposures provide an excellent opportunity to study the growth of collisional continental margins through the processes of terrane accretion, magmatism, accretionary prism development, and subduction of oceanic spreading ridges. Kodiak Island is one of the world's best exposed accretionary complexes, and is characterized by transport along dominant large-magnitude strike-slip faults of west North America and South Alaska. In this study we focus on detrital zircon dating of the Kodiak accretionary complex on Kodiak Island Alaska. Accretionary complexes are an important fundamental element of convergent plate margins and are also important structures in continental crust formation. Their presence in the geologic record is an indicator of past subduction zones. Six graywacke detrital zircon samples from the Kodiak and the Ghost Rocks Formations were analyzed using U/Pb dating of single crystals via laser-ablation inductively coupled plasma mass spectroscopy. The maximum depositional age of the three major formations are as follow: Kodiak Formation 56.2-69.2 Ma, and Ghost Rock 58.5 Ma. The age for the small outcrop of Narrow Cape Formation is 54.1. Kodiak and Ghost Rock Formation detrital zircon age are consistent with fossil ages of these two formations, but the fossil content of Narrow Cape is younger than the detrital zircon age we measured for this formation. Some evidence in our data like resurrection of certain age zircon grains between the accreted sequences, age gaps between the accreted sequences, different rate of sedimentation and etc. are evidenc for episodical accretion in the complex and also displacement of the accreted units along the west North America and Alaska right lateral large magnitude strike slip faults.

Book American Doctoral Dissertations

Download or read book American Doctoral Dissertations written by and published by . This book was released on 1981 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Tectonostratigraphic Terranes of the Circum Pacific Region

Download or read book Tectonostratigraphic Terranes of the Circum Pacific Region written by D. G. Howell and published by . This book was released on 1985 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Petroleum Abstracts Literature and Patents

Download or read book Petroleum Abstracts Literature and Patents written by and published by . This book was released on 1987 with total page 1348 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Comprehensive Dissertation Index

Download or read book Comprehensive Dissertation Index written by and published by . This book was released on 1973 with total page 1016 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Phanerozoic Tectonic Evolution of the Circum North Pacific

Download or read book Phanerozoic Tectonic Evolution of the Circum North Pacific written by Warren J. Nokleberg and published by . This book was released on 2001 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Mesozoic Assembly of the North American Cordillera

Download or read book Mesozoic Assembly of the North American Cordillera written by Robert S. Hildebrand and published by Geological Society of America. This book was released on 2013-01-01 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In this well-illustrated book, Hildebrand expands upon his model for the development of the North American Cordillera detailed in Special paper 457. Starting with an overview of Cordilleran geology he goes on to provide an in depth look at how the Rubian ribbon continent was assembled. He integrates the complex geology of the Cordillera into an actualistic model involving arc magmatism, arc-continent collision, slab failure magmatism, and transcurrent motion in both Rubia and the western North American margin. While much of the focus is on the assembly of the Rubian ribbon continent, Hildebrand explores its interactions with North America during the Sevier and Laramide events and concludes that North America was the lower plate in both"--Provided by publisher.

Book Geophysics Tectonics Abstracts

Download or read book Geophysics Tectonics Abstracts written by and published by . This book was released on 1987 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Tectonic Growth of a Collisional Continental Margin

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.

Book Tectonics Metallogeny and Discovery

Download or read book Tectonics Metallogeny and Discovery written by Maurice Colpron and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This summary report commences with a brief metallogenic overview of the northern Pacific Rim, with particular attention paid to the world-class Mesozoic and Cenozoic ore deposits that define the region's premier metallogenic provinces. This is followed by a summary of the relative attractiveness of the region's various mining jurisdictions, as recorded by recent exploration activity.