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Testing And Refining The Glacial Chronologies In The Sierra Nevada Using 10be Cosmogenic Nuclide Surface Exposure Dating And Schmidt Hammer Methods
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Book Synopsis Testing and Refining the Glacial Chronologies in the Sierra Nevada Using 10Be Cosmogenic Nuclide Surface Exposure Dating and Schmidt Hammer Methods by : Michelle J Morency
Download or read book Testing and Refining the Glacial Chronologies in the Sierra Nevada Using 10Be Cosmogenic Nuclide Surface Exposure Dating and Schmidt Hammer Methods written by Michelle J Morency and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Surface Exposure Geochronology Using Cosmogenic Nuclides by : Edward Jeremy Brook
Download or read book Surface Exposure Geochronology Using Cosmogenic Nuclides written by Edward Jeremy Brook and published by . This book was released on 1993 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cosmogenic 3He, 26A1, and 10Be have been measured in a variety of Antarctic glacial deposits in the McMurdo Sound-Dry Valleys region. The goals of this project were to provide age constraints for Antarctic glacial events, to investigate production mechanisms of 3He, lOBe, and 26 A1 in terrestrial rocks, to constrain the importance of loss of 3He from quartz due to diffusion, and to refine methods of exposure-age dating. Moraines deposited in Arena Valley by the Taylor Glacier, an outlet glacier of the East Antarctic Ice Sheet, have exposure ages from ~120 kyr to 2 myr. 10Be and 3He ages of 122 ± 29 and 134 ±54 kyr, respectively, for the Taylor II moraine are consistent with deposition during isotope stage Se (~ 120 kyr) and with aerial expansions of the East Antarctic Ice Sheet during interglacial periods. Mean 10Be exposure ages for older moraines in the valley are 362 ± 26 kyr (Taylor III), 1.1 ± 0.1 myr (Taylor IVa) and 1.9 ± 0.1 myr (Taylor IVb). Because these older moraines were deposited at most ~200m above the Taylor II limit their ages suggest that major ice sheet advances during the last 2 myr have been broadly similar in magnitude to changes during the last glacial-interglacial cycle. 10Be ages for stratigraphically older drift deposited by the Taylor Glacier allow extension of this conclusion to ~ 3 myr. lOBe measurements in high altitude, pre-Pleistocene glacial deposits in the Dry Valleys preclude rapid uplift of the Transantarctic Mountains (400-1000 m/myr) suggested by controversial biostratigraphic studies of Sirius Group tills. Comparison of measured lOBe concentrations in Sirius Group deposits with those predicted with a model of the effects of uplift on 10Be production suggests minimal uplift of the Transantarctic Mountains over the last 3 myr. 3He, 10Be and 26A1 ages for the "late Wisconsin" Ross Sea Drift, a glacial drift deposited on the coast of McMurdo Sound by the Ross Sea Ice Sheet, range from 8-106 kyr. The age range suggests that this deposit does not, as previous studies suggested, represent a single ice advance in response to lowered sea level at the last glacial maximum. The age range may reflect several ice sheet advances during the last glacial period. Paired measurements of 3He and 10Be in a number of quartz sandstones from the Dry Valleys region show that cosmogenic 3He is not completely retained on time scales of greater than 200 kyr. The 3He and 10Be data, combined with measurements of 3He concentrations in quartz as a function of grain size, suggest effective 3He diffusion coefficients in quartz from ~10-19 to 10-17 cm2 s-1. These values are one to three orders of magnitude greater than previous experimental determinations extrapolated to low temperature. The data also suggest that 3He diffusion rates in quartz do not follow simple volume diffusion trends and are probably sample dependent. Crushing quartz grains in vacuo releases variable concentrations of 3He and 4He and releases helium with surprisingly high isotopic compositions, up to 148 x Ra (Ra = atmospheric 3He/4He ratio: 1.384 x 10-6). The high ratios suggest that crushing releases cosmogenic 3He. As a result, in vacuo crushing cannot be used to correct 3He concentrations in quartz for a magmatic or "non-cosmogenic" component, as is possible in olivine and clinopyroxene phenocrysts in volcanic rocks. Replicate analyses of quartz samples show widely varying 4He concentrations and constant 3He concentrations. These data allow constraint of the nucleogenic 3He/4He production ratio to less than 0.05 ± 0.2 Ra. Corrections to exposure ages for nucleogenic 3He are in most cases
Book Synopsis Development and Calibration of the Cosmogenic 36Cl Surface Exposure Dating Method and Its Application to the Chronology of Late Quaternary Glaciations by : Marek G. Zreda
Download or read book Development and Calibration of the Cosmogenic 36Cl Surface Exposure Dating Method and Its Application to the Chronology of Late Quaternary Glaciations written by Marek G. Zreda and published by . This book was released on 1994 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Development and Calibration of the Cosmogenic 36C1 Surface Exposure Dating Method and Its Application to the Chronology of Late Quaternary Glaciations by : Marek G. Zreda
Download or read book Development and Calibration of the Cosmogenic 36C1 Surface Exposure Dating Method and Its Application to the Chronology of Late Quaternary Glaciations written by Marek G. Zreda and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Regional Correlations of Late Pleistocene Climatic Changes Based on Cosmogenic Nuclide Exposure Dating of Moraines in Idaho by : Cody Sherard
Download or read book Regional Correlations of Late Pleistocene Climatic Changes Based on Cosmogenic Nuclide Exposure Dating of Moraines in Idaho written by Cody Sherard and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiple post-last glacial maximum (LGM) moraines occur in the Sawtooth Range of the Rocky Mountains in central Idaho. Although relative ages of the moraines have been studied, few numerical ages exist for these moraine sequences. In this study, the ages of LGM and late glacial (Younger Dryas) moraines in the Redfish Lake drainage of Idaho are constrained with 23 new, cosmogenic, 10Be dates. Results of this study include developing a new chronology for the Redfish Lake late Pleistocene moraines that are consistent with regional morainal ages. New cosmogenic 10Be data from boulders on Bull Lake moraines at Redfish Lake are consistent with other dates obtained from Bull Lake moraines elsewhere in the Rocky Mountains. Ages of 107 to 206 ka and 238 to 323 ka suggest synchroniety with other Bull Lake glacial advances in the Wind River Range, Tetons, and Yellowstone. New cosmogenic 10Be data from boulders on terminal moraines in Redfish Lake valley, Idaho, show a LGM at 18.5 ± 0.9 ka to 15.6 ± 0.8 ka, recessional (or minor readvance) moraines deposited between 15.4 ± 0.7 ka and 14.2 ± 0.7 ka; and a Younger Dryas (YD) phase at 11.4-11.7 ± 0.5 ka. Boulders on an LGM moraine at Alturas Lake, Idaho were 10Be dated in order to supplement and test the existing concepts of glaciation there. Ages of 17.2 ± 1.0 ka and 16.8 ± 0.8 ka indicate that this moraine is late Pinedale, not mid-Pinedale as previously suggested by Thackray et al. (2004). The late Pleistocene ice chronology at Redfish Lake is consistent with the glacial chronology in the Wind River Range, WY (LGM 24 ka to l8 ka; recessional deposits 18 ka to 16 ka and YD 11.5 ka); Yellowstone, WY (LGM advances: 29.5-22.5 ka, and 19.5- 5.5 ka); Wallowa Mountains, OR (two 10Be dated LGM advances: 21.1 ± 0.4 ka and 17.0 ± 0.3 ka, and YD advance: 10.2 ± 0.6 ka); Crowfoot Lake, Canada (YD advance: 11,330 ± 220-10,100 ± 70 14C yrs B.P.); and many other places throughout western North America. This research provides chronological constraints on Pinedale LGM (~18.5 ka) moraines, Pinedale recessional (between 18.5 and 14.2 ka) moraines, and Younger Dryas (~11.4 ka) moraines in the Sawtooth Range of the Rocky Mountains, and assists in determining the areal extent of the late Pleistocene cold period in the Western United States.
Book Synopsis Quaternary Dating Methods by : Mike Walker
Download or read book Quaternary Dating Methods written by Mike Walker and published by John Wiley & Sons. This book was released on 2013-04-30 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: This introductory textbook introduces the basics of dating, the range of techniques available and the strengths and limitations of each of the principal methods. Coverage includes: the concept of time in Quaternary Science and related fields the history of dating from lithostratigraphy and biostratigraphy the development and application of radiometric methods different methods in dating: radiometric dating, incremental dating, relative dating and age equivalence Presented in a clear and straightforward manner with the minimum of technical detail, this text is a great introduction for both students and practitioners in the Earth, Environmental and Archaeological Sciences. Praise from the reviews: "This book is a must for any Quaternary scientist." SOUTH AFRICAN GEOGRAPHICAL JOURNAL, September 2006 “...very well organized, clearly and straightforwardly written and provides a good overview on the wide field of Quaternary dating methods...” JOURNAL OF QUATERNARY SCIENCE, January 2007
Book Synopsis Antarctic Glacial Chronology: New Constraints from Surface Exposure Dating by :
Download or read book Antarctic Glacial Chronology: New Constraints from Surface Exposure Dating written by and published by . This book was released on 2000 with total page 215 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface exposure dating using 3He, Ne-21 and Cl-36 combined with mapping of moraines, provide new constraints on West Antarctic Ice Sheet (WAIS) chronology. New He-3 production rates are determined from a 125 ka lava flow. Measurements of inherited He-3/He-4 in two common Antarctic lithologies allow measurement of exposure ages 6000 years. At Mt. Waesche, a moraine band records interior WAIS elevations higher than present. Surface exposure ages indicate that the last ice highstand occurred 10 +/- 1 ka. The data constrain past WAIS behavior and ice volume. Surface exposure ages place age constraints on six Beardmore Glacier drifts. Two drifts record damming of the glacier during the last glacial maximum (10-20 ka) by an expanded WAIS. The four older drifts record similar damming by the WAIS approx. 600 ka, approx. 1 Ma, and approx. 2 Ma. Moraines of Koettlitz Glacier also record damming by the WAIS prior to the LGM. The oldest moraines are 400 ka. Independent stratigraphic control allows evaluation of prior exposure, cover and determination of erosion rates. Taken together, the results are consistent with sea level control of WAIS extent; the WAIS probably has fluctuated synchronously with the Northern Hemisphere ice sheets for at least the last 1 million years.
Book Synopsis Glacial Response to Global Climate Changes by : Stefan Strasky
Download or read book Glacial Response to Global Climate Changes written by Stefan Strasky and published by . This book was released on 2008 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Application of Cosmogenic Nuclides and Argon Geochronology to Paleoclimate, Paleomagnetism, and Paleohydrology by : Andrea M. Balbas
Download or read book Application of Cosmogenic Nuclides and Argon Geochronology to Paleoclimate, Paleomagnetism, and Paleohydrology written by Andrea M. Balbas and published by . This book was released on 2016 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation uses argon geochronology and cosmogenic nuclide surface exposure dating methods to address three research questions. The first question concerns a geomagnetic instability recorded in lava flows on the island of Floreana in the Galapagos Archipelago. Changes in the Earth’s magnetic field (intensity and orientation) occur frequently throughout geologic time for reasons not yet fully understood. Accurately dating these changes is important because these events provide critical stratigraphic markers in many natural archives, and constraints on the timing of geomagnetic change help better our understanding of the geodynamo. The lava flow on Floreana records an 86% reduction in field strength and intermediate virtual geomagnetic pole (VGP) orientations. Our age determination of 925.7 ± 4.6 ka (2[sigma]; n = 6; MSWD = 1.23) indicates that this flow and the flows associated with it that record nearly identical VGP’s, record the Santa Rosa Excursion. We confirm that this site records the second reported terrestrial evidence of this geomagnetic excursion. Our age is in agreement with sediment records, which indicate this event spanned 3 kyrs. The Santa Rosa Excursion can now be characterized as a global short-lived geomagnetic anomaly associated with an 86% reduction in field strength in equatorial regions (as compared to modern day field strength). Similarities between the Santa Rosa and Laschamp excursions illustrate that such events can occur when the geomagnetic field is either in its reversed or normal polarity state. The second research question addresses the timing of the most recent polarity transition of Earth's magnetic field. The Matuyama-Brunhes (M-B) polarity transition is the most well-studied of all polarity transitions however it's timing remains in debate. A ~10 kyrs mismatch between volcanic and sedimentary archives that record the reversal have been reported. Important geodynamic insights can be gained by examining the structure of a reversing field through time, and the reliability of such studies requires accurate and precise timing of geomagnetic change. We use argon geochronology to date 13 Tahitian lava flows known to record the M-B reversal. A reconciliation between our new ages and those from previous literature from sedimentary and volcanic archives resolves this apparent temporal mismatch and suggests ~35 kyrs of instability and millennial to centennial timescale changes in VGP orientations prior to the Brunhes chron. This new illustration of the structure of a reversing field through time offers new insights into the short precursor history of a reversing field and the rapid -- if not erratic -- changing field dynamics during periods of low-dipole intensity. The final research question involves establishing the timing of intermittent catastrophic drainage of Glacial Lake Missoula in Montana and the associated large-scale flooding across the Columbia Basin and down the Columbia River to the Pacific Ocean during the last ice age. During the period from ~22,000 to ~13,000 years ago, there were perhaps 100 such flooding events that each lasted perhaps several weeks, with the amount of water in each flood being equivalent to ~20 times all of the world’s river flow combined. Surface exposure ages of boulders deposited by such floods at key geomorphic features can be used to determine flood routing, timing, and magnitude. This data may also suggest a source region of floods through time and help constrain the timing of Okanogan Lobe retreat. Eleven new site ages for flood related geomorphic features reveal the interplay between the Cordilleran Ice Sheet and the megafloods. We show that a large megaflood occurred at ~17.2 ka and traveled through an open northern Columbia River throughway before the advance of the Okanogan Lobe and impoundment of Glacial Lake Columbia. Okanogan Lobe retreat occurred between 14.0 to 14.8 ka and floods that occurred after Okanogan retreat were not as large as those before blockage of the northern Columbia. The relatively late retreat of the Okanogan Lobe as compared to the Puget Lobe may reflect independent controls on ice-sheet behavior. Radiocarbon ages indicating the minimum age of human occupation of the Pacific Northwest of the United States in combination with our most recent site ages suggest humans may have witnessed some of the youngest megafloods, which dramatic character likely influenced their oral traditions.
Book Synopsis 10Be Surface Exposure Dating of the Rhone- and the Aare-glacier by : Melissa Martina Graber
Download or read book 10Be Surface Exposure Dating of the Rhone- and the Aare-glacier written by Melissa Martina Graber and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Glacial World According to Wally by : Wallace S. Broecker
Download or read book The Glacial World According to Wally written by Wallace S. Broecker and published by . This book was released on 1995 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Cosmogenic Nuclides by : Tibor J. Dunai
Download or read book Cosmogenic Nuclides written by Tibor J. Dunai and published by Cambridge University Press. This book was released on 2010-03-04 with total page 199 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first book to provide a comprehensive and state-of-the-art introduction to the novel and fast-evolving topic of in-situ produced cosmogenic nuclides. It presents an accessible introduction to the theoretical foundations, with explanations of relevant concepts starting at a basic level and building in sophistication. It incorporates, and draws on, methodological discussions and advances achieved within the international CRONUS (Cosmic-Ray Produced Nuclide Systematics) networks. Practical aspects such as sampling, analytical methods and data-interpretation are discussed in detail and an essential sampling checklist is provided. The full range of cosmogenic isotopes is covered and a wide spectrum of in-situ applications are described and illustrated with specific and generic examples of exposure dating, burial dating, erosion and uplift rates, and process model verification. Graduate students and experienced practitioners will find this book a vital source of information on the background concepts and practical applications in geomorphology, geography, soil-science, and geology.
Book Synopsis Geomorphology by : Robert S. Anderson
Download or read book Geomorphology written by Robert S. Anderson and published by Cambridge University Press. This book was released on 2010-06-17 with total page 655 pages. Available in PDF, EPUB and Kindle. Book excerpt: A modern, quantitative, process-oriented approach to geomorphology and the role of Earth surface processes in shaping landforms, starting from basic principles.
Book Synopsis Geomorphological Techniques by : Andrew Goudie
Download or read book Geomorphological Techniques written by Andrew Goudie and published by Routledge. This book was released on 2003-09-02 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt: The specialist contributors to Geomorphological Techniques have thoroughly augmented and updated their original, authoritative coverage with critical evaluations of major recent developments in this field. A new chapter on neotectonics reflects the impact of developments in tectonic theory, and heavily revised sections deal with advances in remote sensing, image analysis, radiometric dating, geomorphometry, data loggers, radioactive tracers, and the determination of pore water pressure and the rates of denudation.
Book Synopsis Geomorphological Landscapes of the World by : Piotr Migon
Download or read book Geomorphological Landscapes of the World written by Piotr Migon and published by Springer Science & Business Media. This book was released on 2010-01-22 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: Physical landscapes are one of the most fascinating facets of our Planet, which tell stories about the evolution of the surface of the Earth. This book provides up-to-date information about the geomorphology of the selected ‘classic’ sites from around the world and shows the variety of geomorphological landscapes as moulded by different sets of processes acting over different timescales, from millions of years to days. The volume is written by nearly fifty geomorphologists from more than twenty countries who for many years have researched some of the unique sceneries on the planet. The thirty six chapters present each continent of the world. They describe landscapes of different origin, so that the reader can learn about the complexity of processes behind the sceneries. This is a useful reference book, linking geomorphology with global initiatives focused on nature conservation.
Book Synopsis A Practical Guide to the Study of Glacial Sediments by : David J. A. Evans
Download or read book A Practical Guide to the Study of Glacial Sediments written by David J. A. Evans and published by Routledge. This book was released on 2014-04-23 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sediments are the most valuable form of physical evidence for past Earth surface processes. They have the potential to build up an archive of events and provide a window into the past. Through careful examination of sediments the shifting patterns of surface processes across space and time are revealed, allowing us to reconstruct past environments and environmental change. A Practical Guide to the Study of Glacial Sediments is a guide to the standard techniques employed to read the sedimentary record of former glaciers and ice sheets. It demonstrates that the often complex and fragmentary glacial sedimentary record can, when examined systematically and rationally, provide detailed insights into former environments and climates in places where no other evidence is available. The complementary techniques covered in this book include: facies description, grain size analysis, clast form assessment, clast macrofabric analysis, micromorphology, particle lithology and assessment of engineering properties. They yield consistent and meaningful results in a range of glacial depositional environments throughout the world, from the high Arctic to the Himalayas. A Practical Guide to the Study of Glacial Sediments provides students and researchers with a clear and accessible guide to recording and interpreting glacial successions wherever the location.
Book Synopsis The Magnetic Field of the Earth by : Ronald T. Merrill
Download or read book The Magnetic Field of the Earth written by Ronald T. Merrill and published by Academic Press. This book was released on 1998 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: Topics involved in studies of the Earth's magnetic field and its secular variation range from the intricate observations of geomagnetism, to worldwide studies of archeomagnetism and paleomagnetism, through to the complex mathematics of dynamo theory. Traditionally these different aspects of geomagnetism have in the main been studied and presented in isolation from each other. This text draws together these lines of inquiry into an integrated framework to highlight the interrelationships and thus to provide a more comprehensive understanding of the geomagnetic field.
