Download or read book Detrital Zircon Uranium lead Geochronology and Hafnium isotope Analyses of Passive Margin and Roberts Mountains Allochthon Strata written by Gwen Margaret Linde and published by . This book was released on 2016 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation investigated Neoproterozoic–Devonian units of the western Laurentian passive margin and Roberts Mountains allochthon (RMA) and determined U-Pb detrital ages and Hf isotope zircon analyses that provide new insights into the early Paleozoic tectonics of western Laurentia. The three chapters investigate several difficult questions and contradictions in the understanding of early Paleozoic tectonism in western Laurentia through analysis of sedimentary units. The provenance, depositional histories, and tectonic evolution of the lower Paleozoic sedimentary strata of north-central Nevada have long been subjects of speculation and debate. Detrital zircon U-Pb geochronology and Hf-isotope analyses indicate the provenance, sedimentary distribution patterns, and tectonic evolution of Upper Neoproterozoic–Cambrian passive margin strata and Ordovician–Devonian strata of the RMA, with a special emphasis on the enigmatic Harmony Formation. The study reported in Chapter 1 uses detrital zircon U-Pb geochronology to determine whether or not the Upper Neoproterozoic–Lower Cambrian Osgood Mountain Quartzite and the Upper Cambrian–Lower Ordovician Preble Formation in the Osgood Mountains of northern Nevada were units of the western Laurentian passive margin. Within the Osgood Mountain Quartzite, U-Pb age populations of the detrital zircons shift with stratal age. This shift indicates that the zircons were shed in different proportions from the source terranes, which suggests a change in provenance within the Osgood Mountain Quartzite. These changes are consistent across a Great Basin transect of coeval passive margin strata. The change in provenance is due to a shift in sedimentary transport patterns, which was caused by the Late Neoproterozoic-Early Cambrian uplift of the Transcontinental Arch. This study provided independent corroboration of the existence of the Transcontinental Arch and better precision for the timing at which the Arch uplifted. The study also recorded the impact of the uplifted Arch on continent-wide sediment dispersal patterns—the change in predominant source terranes—and confirmed the Arch as a sediment source for passive-margin strata. Regional coeval changes in detrital zircon U-Pb age patterns provide a correlative tool in unfossiliferous sediments and could be useful in future studies. Chapter 2 describes how detrital zircon U-Pb geochronology and Hf-isotope analyses were used to determine the provenance, sedimentary transport, and tectonic evolution of RMA strata. Workers have speculated for decades, with little agreement, on the origin, depositional basin(s), and subsequent tectonic transport of the RMA. Zircon grains from six Ordovician to Devonian arenite samples were analyzed for U-Pb ages; approximately one-quarter of these grains were further analyzed for Hf isotope ratios. Five of the studied units have similar U-Pb age populations and Hf-isotope ratios, while the U-Pb ages and Hf-ratios of the Ordovician lower Vinini Formation are significantly different. Comparison of these data with known analyses of igneous basement rocks and other sedimentary units of Laurentia reveals that the lower Vinini Formation originated in the north-central Laurentian craton. The other five units, as well as Ordovician passive margin sandstones of the western Laurentian margin, had a common source in the Peace River Arch region of western Canada. All of the RMA strata were deposited near the Peace River Arch region and subsequently tectonically transported south along the Laurentian margin, from where they were emplaced onto the craton during the Antler orogeny. This study determined the origin, location of the depositional basin, and proposed a subsequent tectonic evolution that accounts for origin, deposition, and current location of the RMA strata. Chapter 3 describes the origin, age, and tectonic development of the Harmony Formation. The Harmony Formation has always been difficult to explain—it is mostly an immature feldspathic arenite, which would argue for minimal transport from origin to deposition. However, its general position as the top thrust plate in the RMA stack argues for deposition oceanward of other more texturally mature RMA strata. The age of the Harmony Formation is equally contentious—published age determinations range from Cambrian to Mississippian. Zircon grains from ten arenite samples were analyzed for U-Pb ages; grains from eight of these samples were further analyzed for Hf-isotope ratios. Seven of the arenite units have similar U-Pb age peaks and Hf isotope ratios, whereas three differ significantly. The data confirmed the subdivision of the Harmony Formation into two petrofacies, quartzose (Harmony A) and feldspathic (Harmony B). Harmony A originated in the central Laurentian craton. Harmony B had a common source in eastern Alberta–western Saskatchewan, north of the source of the Harmony A. All of the Harmony Formation strata were deposited near eastern Alberta in Late Neoproterozoic through Cambrian time and subsequently tectonically interleaved with the Roberts Mountains allochthon strata. The entire package was tectonically transported south along the Laurentian margin. Subsequently, it was emplaced eastward onto the craton during the Late Devonian to Early Mississippian Antler orogeny. This study proposed a reasonable solution to one of the longest enduring and most puzzling conundrums of the western Cordillera—the origin, age, and transport of the Harmony Formation. These three studies demonstrated the utility of detrital zircon U-Pb geochronology and Hf-isotope analyses in better understanding difficult sedimentary and tectonic problems. The studies also provided new insights into the Early Paleozoic tectonic evolution of western Laurentian.
Download or read book Detrital Zircon Uranium lead Geochronology of the Schoonover Sequence Golconda Allochthon and the Yokuts Pendants Western Sierra Nevada Mountains written by Nancy Chen and published by . This book was released on 2016 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Uranium lead zircon geochronology hafnium isotope and trace element geochemistry of a unique lower crustal upper mantle section of a dying slow spreading mid ocean ridge Macquarie Island Southern Ocean written by Charles Ryan Jeffcoat and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book In situ hafnium and lead isotope analyses of detrital zircons from the Devonian sedimentary basin of NE Greenland written by T.-L. Knudsen and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Isotopic Geochemistry of Uranium and Lead written by John Laurence Kulp and published by . This book was released on 1960 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Provisional Zircon and Monazite Uranium Lead Geochronology for Selected Rocks from Vermont written by U.S. Department of the Interior and published by CreateSpace. This book was released on 2014-03 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the results of zircon uranium-lead geochronologic analysis of 24 rock samples collected and analyzed in support of the "Bedrock Geologic Map of Vermont" by Ratcliff and others. The samples in this study were collected from mapped exposures identified while conducting either new, detailed geologic quadrangle mapping or reconnaissance mapping, both of which were used for compilation of the bedrock geologic map of Vermont.
Download or read book U Pb and Hf Analysis of Detrital Zircons written by Kylie J. Matonia and published by . This book was released on 2009 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Provision Zircon and Monazite Uranium Lead Geochronology for Selected Rocks from Vermont written by U.S. Department of the Interior and published by CreateSpace. This book was released on 2014-04-28 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the results of zircon uranium-lead geochronologic analyses of 24 rock samples collected and analyzed in support of the "Bedrock Geological Map of Vermont" by Ratcliffe and others (in press).
Download or read book Constraints on the Formation of the Bitterroot Lobe of the Idaho Batholith Idaho and Montana from U Pb Zircon Geochronology and Feldspar Pb Isotopic Data written by Margo I. Toth and published by . This book was released on 1992 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geological Survey s Work on Isotope Geology of Uranium Thorium and Their Decay Products written by Ralph Smyser Cannon and published by . This book was released on 1952 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Preliminary Determination of the Age of Some Colorado Plateau Uranium Ores by the Lead uranium Method written by Lorin Rollins Stieff and published by . This book was released on 1953 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Zircon written by John M. Hanchar and published by de Gruyter. This book was released on 2003 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chapter titles: Structure and chemistry of zircon and zircon-group minerals; The composition of zircon and igneous and metamorphic petrogenesis; Melt inclusions in zircon; Zircon saturation thermometry; Diffusion in zircon; Historical development of zircon geochronology; Zircon U-Th-Pb geochronology by ID-TIMS; Considerations in zircon geochronology by SIMS; Present trends and the future of zircon in geochronology: laser ablation ICPMS; Detrital zircon analysis of the sedimentary record; High-precision U-Pb zircon geochronology and the stratigraphic record; Lu-Hf and Sm-Nd isotope systems in zircon; Oxygen isotopes in zircon; Radiation effects in zircon; Spectroscopic methods applied to zircon; Atlas of zircon textures.
Download or read book Spot U Pband Hf Isotope Analyses of Detrital Zircons from the Khondalites in the Western Block of the North China Craton written by Xiaoping Xia and published by . This book was released on 2017-01-26 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Combined U Pb geochronology and Hf isotope geochemistry of detrital zircons from early Paleozoic sedimentary rocks Ellsworth Whitmore Mountains block Antarctica written by M.J. Flowerdew and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Compilation of SHIRMP U Pb Zircon Geochronology Data 1994 written by D. R. Nelson and published by . This book was released on 1995 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applications of Detrital Zircon Geochronology and Isotope Geochemistry in Provenance Study written by and published by . This book was released on 2013 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provenance study is a fundamental element of basin analysis, where understanding of sedimentation patterns and their driving mechanisms often requires information about the source of basin sediments. Many recent studies have turned to the geochronology (particularly single detrital zircon ages) and isotope geochemistry in sedimentary rocks to derive detailed information about sediment sources. This dissertation applies geochronology and isotope geochemistry to provenance questions in different settings, utilizing zircon U/Pb ages, feldspar common Pb isotope ratios, and carbonate 87Sr/86Sr ratios to gain new insights into provenance in three well-studied sedimentary systems. The first chapter, set in the Gualala Basin of northern California, provides an example of how conventional provenance indicators, detailed study of conglomerate clasts, U/Pb zircon ages, and common Pb isotope ratios of feldspar from the sand-sized fraction can all provide useful information. Combined, these different data types can produce a more complete picture of sedimentary source areas than any of them would be able to alone. In a continued investigation of applications for detrital zircon ages in provenance study, the second chapter develops a new "Confidence Envelope" method for comparing age distributions. The method developed here is based on characterizing the expected range of variability in samples drawn from the age distribution of a proposed sediment source area, and testing whether a sample of unknown provenance falls within that range. Using the uniquely well-constrained setting of the Green River Formation in Wyoming, the last two chapters investigate paleo-water provenance using an unprecedented dataset of 87Sr/86Sr ratios and Sr concentrations, compiled from both new data and data collected from previous studies. These data demonstrate that isotopic ratios in the Green River Formation lacustrine system changed rapidly, therefore lacustrine sediments were an extremely high-resolution recorder of lacustrine Sr evolution.
Download or read book Geochronology written by Christopher T. Harper and published by . This book was released on 1973 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt:
