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Late Quaternary Glacier Fluctuations And Vegetation Change In The Northwestern Ahklun Mountains Southwestern Alaska
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Book Synopsis Late Quaternary Glacier Fluctuations and Vegetation Change in the Northwestern Ahklun Mountains, Southwestern Alaska by : Yarrow L. Axford
Download or read book Late Quaternary Glacier Fluctuations and Vegetation Change in the Northwestern Ahklun Mountains, Southwestern Alaska written by Yarrow L. Axford and published by . This book was released on 2000 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Quaternary Glaciations - Extent and Chronology by : J. Ehlers
Download or read book Quaternary Glaciations - Extent and Chronology written by J. Ehlers and published by Elsevier. This book was released on 2004-10-02 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the second of three volumes in which the recent knowledge of the extent and chronology of Quaternary glaciations has been compiled on a global scale. This information is seen as a fundamental requirement, not only for the glacial community, but for the wider user-community of general Quaternary workers. In particular the need for accurate ice-front positions is a basic requirement for the rapidly growing field of palaeoclimate modelling. In order to provide the information for the widest-possible range of users in the most accessible form, a series of digital maps was prepared. The glacial limits were mapped in ArcView, the Geographical Information System (GIS) used by the work group. Included with the publication is a CD with digital maps, showing glacial limits, end moraines, ice-dammed lakes, glacier-induced drainage diversions and the locations of key sections through which the glacial limits are defined and dated. The last deglaciation is also shown in 500 year time-steps. The digital maps in this volume cover the USA and Canada and include Greenland and Hawaii. Both overview maps and more detailed maps at a scale 1: 1,000,000 are provided. Also available:Part I: Europe, ISBN 0-444-51462-7Part III: South America, Asia, Africa, Australia, Antarctica, ISBN 0-444-51593-3
Book Synopsis Late Pleistocene Glacial Chronology of the Western Ahklun Mountains, Southwestern Alaska by : Jason P. Briner
Download or read book Late Pleistocene Glacial Chronology of the Western Ahklun Mountains, Southwestern Alaska written by Jason P. Briner and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: New glacial mapping and 35 cosmogenic 36Cl surface exposure ages, the first ever reported from Alaska , constrain the extent and timing of late Pleistocene glacial fluctuations in the western Ahklun Mountain s, southwe stern Alaska. Morphometric and soil relativeage data characterize two main drift units deposited during the Arolik Lake and Klak Creek glaciations , named herein. During the Arolik Lake glaciation (early Wisconsin), outlet glaciers emanated from an ice cap over the central portion of the Ahklun Mountains and deposited moraines at or beyond the modern coast. These moraines have slope angles averaging about 11℗ʻ and crests averaging about 35 m wide . Four moraine boulders deposited during this glaciation have a weighted mean surface exposure age of 53.6 ℗ł 2.0 36Cl ka. During the Klak Creek glaciation (late Wisconsin), ice-cap outlet glaciers deposited moraines 20-80 km up-valley from Arolik Lake moraines. Valley glaciers expanded from high massifs that fringe the major river valleys in the western Ahklun Mountains and terminated independently from the relatively restricted ice-cap outlet glaciers. Moraines deposited during the Klak Creek glaciation have steeper slopes (mean = -18℗ʻ) and sharper crests (mean= about 17 m) than do Arolik Lake moraines. Twenty-eight 36Cl ages were obtained from six Klak Creek moraines from three valleys and reveal two phases of glaciation during the late Wisconsin, one from about 25 to 23 36Cl ka, and another from 19 to 15 36Cl ka. An ice-cap outlet glacier moraine underlies a valley glacier terminal moraine, both of which have ages of 18-19 36Cl ka, and indicates that the ice-cap outlet glacier had retreated from its maximum position shortly before the valley glacier reached its maximum position. Equilibrium-line altitudes (ELAs) for reconstructed Klak Creek valley glaciers average about 400 m, which is only about 200 m below the estimated modem altitude. The restricted extent of Klak Creek glaciers might reflect a lack of available moisture as sea ice covered the Bering Sea during the peak of the last global glacial maximum. When compared to the marine oxygen-isotope record, the timing of glacier advances in the western Ahklun Mountains indicates that glaciers responded to both regional and global climate changes.
Book Synopsis Late Holocene Glacier Fluctuations, Northeastern Ahklun Mountains, Southwestern Alaska by : Laura B. Levy
Download or read book Late Holocene Glacier Fluctuations, Northeastern Ahklun Mountains, Southwestern Alaska written by Laura B. Levy and published by . This book was released on 2002 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Late Quaternary Vegetation and Lake Level Changes in Central Alaska by : Nancy Horner Bigelow
Download or read book Late Quaternary Vegetation and Lake Level Changes in Central Alaska written by Nancy Horner Bigelow and published by . This book was released on 1997 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Late Holocene Climate Fluctuations at Cascade Lake, Northeastern Ahklun Mountains, Southwestern Alaska by : Kasey Kathan
Download or read book Late Holocene Climate Fluctuations at Cascade Lake, Northeastern Ahklun Mountains, Southwestern Alaska written by Kasey Kathan and published by . This book was released on 2006 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Late Quaternary Vegetation and Climate History of Southwestern Alaska by : Linda B. Brubaker
Download or read book Late Quaternary Vegetation and Climate History of Southwestern Alaska written by Linda B. Brubaker and published by . This book was released on 1991 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes objectives and partially reviews existing literature for a proposed research project. Objectives of that project include analyzing pollen content of sediment cores from Southwestern Alaska lakes, interpreting the late Quaternary vegetation and climate history of this region based on new and previously existing data, and comparing these histories to those from other regions of Beringia.
Book Synopsis Late Quaternary Glacial Geology, Shoreline Morphology, and Tephrochronology of the Lliamna/Naknek/Brooks Lake Area, Southwestern Alaska by : Karen B. Stilwell
Download or read book Late Quaternary Glacial Geology, Shoreline Morphology, and Tephrochronology of the Lliamna/Naknek/Brooks Lake Area, Southwestern Alaska written by Karen B. Stilwell and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This study focuses on the late-Wisconsin Brooks Lake glaciation, lake-level fluctuations, and volcanic deposits in the lliarnna/Naknek/Brooks Lake area on the northern Alaska Peninsula, southwestern Alaska. The Brooks Lake glaciation consists of five stades, from youngest to oldest: Kvichak, Uiarnna, Newhalen, Iliuk, and Ukak. This thesis reassigns the type Mak Hill moraine to a pre-late-Wisconsin glaciation, and considers the moraine enclosing Naknek Lake an early-late-Wisconsin deposit correlative to either the Kvichak stade, lliarnna stade, or both. The presence in the Iliamna Lake valley, and the absence in the Naknek Lake valley of a two-fold earliest-late-Wisconsin Kvichak/Iliamna glacial sequence suggest that the two glacial systems responded differently to climate change, or glacier/bed dynamics due to differing ice sources and glacier configurations. Plant macrofossils dated at 26,155 ℗ł 285 I4C yr BP afford a new maximum-limiting age on the type Kvichak moraine. Slope angles on the type Kvichak and Iliamna moraines are less steep (~11-15℗ʻ) than on younger Newhalen, lliuk, and Ukak moraines (~18-20℗ʻ ), indicating that a considerable length of time separated the Iliamna and Newhalen stades. Correlation of this time-stratigraphic marker with other better dated Alaskan glacial sequences suggests that the interstadial occurred -13-14 ka. Following late-Wisconsin de glaciation of the Iliamna and Naknek lake basins, lake levels lowered, creating a flight of wave-cut terraces. Horizontal terraces, formed during latest-Wisconsin/early-Holocene time, at ~40 m above Iliamna Lake, and ~15 and ~30 m above Naknek Lake, suggest that these shorelines are not tilted as a result of glacial isostatic rebound or regional tectonism. The most prominent terraces above both lakes lay about halfway between the highest terrace and present-day lake level. If these terraces are correlative, then this indicates some climate control on lake-level fluctuations. Electron-microprobe analysis of six late-Pleistocene tephra samples allows five samples to be correlated with latest-Pleistocene Lethe tephra, and extends the Lethe ash plume ~125 km westward, and ~150 km northwestward of its presumed source area. Analysis of four early-Holocene black tephras fails to support any correlations, suggesting that there are multiple black tephras in the area. Ash C, a tricolored ash, consists of more than one chemically distinct tephra, and there is little consistency between color zones of the ash at different sites.
Book Synopsis Late Holocene Climate Change and Calving Glacier Fluctuations Along the Southwestern Margin of the Stikine Icefield, Alaska by : Robert J. Viens
Download or read book Late Holocene Climate Change and Calving Glacier Fluctuations Along the Southwestern Margin of the Stikine Icefield, Alaska written by Robert J. Viens and published by . This book was released on 2001 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The retreat of large tidewater- and lake-calving glaciers, as well as nearby land-based glaciers, in southeastern Alaska during the middle to late Holocene was primarily triggered by increases in summer temperature. Shakes, LeConte, Patterson, and Baird glaciers, located along the southwestern margin of the Stikine Icefield in southeastern Alaska, experienced two or three major periods of advance and retreat during this period. Historical, stratigraphic, and dendrochronological evidence suggests that these periods of advance culminated approximately 3,500-3,300, 2,700-2,200, 1,100-900, and 220-110 years ago in the study area. Comparison with previously published regional records from glaciers located along the coast of northwestern North America suggests a general synchrony in the timing of ice advance across the region. Regional intervals of ice maxima date approximately 3,000-1,900,1,500-900, and 250-100 years ago, and encompass three of the main periods of advance represented in the study area. To determine a regional cause of glacier synchrony, glacier chronologies were compared to local and regional climate and climate proxies. Summer temperature fluctuations in the study area for the past four centuries were derived from tree-ring-width time-series from Crystal Mountain near Petersburg. Previously published precipitation and summer temperature values, inferred from palynological studies, provide a record of climate change for the last 10,000 Years. Throughout southeastern Alaska, periods of glacier retreat for both calving glaciers and land-based glaciers tend to correlate with periods of warming summer temperature. The collective data imply that the geologic record left by calving glaciers, like that left by 1and-based glaciers. has the potential to serve as an important climate-proxy record in a region where few such records have been studied. Furthermore, such a relationship helps further to quantify calving glacier dynamics and improve prediction of calving-glacier response to human-induced global warming"--Abstract.
Book Synopsis Arctic, Antarctic, and Alpine Research by :
Download or read book Arctic, Antarctic, and Alpine Research written by and published by . This book was released on 2004 with total page 670 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Encyclopedia of Snow, Ice and Glaciers by : Vijay P. Singh
Download or read book Encyclopedia of Snow, Ice and Glaciers written by Vijay P. Singh and published by Springer Science & Business Media. This book was released on 2011-07-01 with total page 1301 pages. Available in PDF, EPUB and Kindle. Book excerpt: The earth’s cryosphere, which includes snow, glaciers, ice caps, ice sheets, ice shelves, sea ice, river and lake ice, and permafrost, contains about 75% of the earth’s fresh water. It exists at almost all latitudes, from the tropics to the poles, and plays a vital role in controlling the global climate system. It also provides direct visible evidence of the effect of climate change, and, therefore, requires proper understanding of its complex dynamics. This encyclopedia mainly focuses on the various aspects of snow, ice and glaciers, but also covers other cryospheric branches, and provides up-to-date information and basic concepts on relevant topics. It includes alphabetically arranged and professionally written, comprehensive and authoritative academic articles by well-known international experts in individual fields. The encyclopedia contains a broad spectrum of topics, ranging from the atmospheric processes responsible for snow formation; transformation of snow to ice and changes in their properties; classification of ice and glaciers and their worldwide distribution; glaciation and ice ages; glacier dynamics; glacier surface and subsurface characteristics; geomorphic processes and landscape formation; hydrology and sedimentary systems; permafrost degradation; hazards caused by cryospheric changes; and trends of glacier retreat on the global scale along with the impact of climate change. This book can serve as a source of reference at the undergraduate and graduate level and help to better understand snow, ice and glaciers. It will also be an indispensable tool containing specialized literature for geologists, geographers, climatologists, hydrologists, and water resources engineers; as well as for those who are engaged in the practice of agricultural and civil engineering, earth sciences, environmental sciences and engineering, ecosystem management, and other relevant subjects.
Book Synopsis Encyclopedia of Quaternary Science by : Cary Mock
Download or read book Encyclopedia of Quaternary Science written by Cary Mock and published by Newnes. This book was released on 2013-03-25 with total page 3883 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second revised edition of the Encyclopedia of Quaternary Science, Four Volume Set, provides both students and professionals with an up-to-date reference work on this important and highly varied area of research. There are lots of new articles, and many of the articles that appeared in the first edition have been updated to reflect advances in knowledge since 2006, when the original articles were written. The second edition will contain about 375 articles, written by leading experts around the world. This major reference work is richly illustrated with more than 3,000 illustrations, most of them in colour. Research in the Quaternary sciences has advanced greatly in the last 10 years, especially since topics like global climate change, geologic hazards and soil erosion were put high on the political agenda. This second edition builds upon its award-winning predecessor to provide the reader assured quality along with essential updated coverage Contains 357 broad-ranging articles (4310 pages) written at a level that allows undergraduate students to understand the material, while providing active researchers with a ready reference resource for information in the field. Facilitates teaching and learning The first edition was regarded by many as the most significant single overview of Quaternary science ever, yet Editor-in-Chief, Scott Elias, has managed to surpass that in this second edition by securing even more expert reviews whilst retaining his renowned editorial consistency that enables readers to navigates seamlessly from one unfamiliar topic to the next
Book Synopsis How Does Climate Change Influence Alaska's Vegetation? by : Thomas Alan Ager
Download or read book How Does Climate Change Influence Alaska's Vegetation? written by Thomas Alan Ager and published by . This book was released on 1997 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Late Pleistocene Glacial Chronology of the Western Ahklun Mountains, Southwest Alaska by : Jason P. Briner
Download or read book Late Pleistocene Glacial Chronology of the Western Ahklun Mountains, Southwest Alaska written by Jason P. Briner and published by . This book was released on 1998 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Ecosystem Approach to the Study of Late-Quaternary Environmental Change in Southwestern Alaska by : Feng Sheng Hu
Download or read book An Ecosystem Approach to the Study of Late-Quaternary Environmental Change in Southwestern Alaska written by Feng Sheng Hu and published by . This book was released on 1994 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Millennial to Annual Scale Paleoclimatic Change in Central Alaska During the Late Quaternary Interpreted from Lake Sediments and Tree Rings by : Valerie Ann Barber
Download or read book Millennial to Annual Scale Paleoclimatic Change in Central Alaska During the Late Quaternary Interpreted from Lake Sediments and Tree Rings written by Valerie Ann Barber and published by . This book was released on 2002 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The theme of this dissertation is the importance of effective moisture (precipitation minus evaporation) in subarctic ecosystems. Interior Alaska has a relatively dry climate with annual precipitation ranging from 25-45 cm. Records from interior Alaska lake sediment cores show low lake levels following the Last Glacial Maximum, with significant increases at 12,000 and 9,000 14C years B.P. Using lake-level reconstructions and models based on modern hydrologic and meteorologic data, we infer precipitation of 35-75% less than modern at 12,000 yr. BP, 25-45% less than modern at 9,000 yr. BP, and 10-20% less than modern at 6,000 yr. BP. Trees were scarce on the interior Alaskan landscape during the late Pleistocene with birch species appearing about 12,000 BP and spruce species approximately 3500 years later. The correspondence between lake-level and vegetation changes suggests that moisture may have been one of the limiting factors in the establishment of these tree species. Alaska climate records show a climatic regime shift in the mid-1970s. Less effective moisture is available over the past 30 years because summer temperatures in interior Alaska have been increasing without a concurrent increase in precipitation. Radial growth of white spruce at 20 low elevation stands in interior Alaska declined corresponding with this climatic change. The observation that moisture limits spruce growth in Alaska today is consistent with our inference of moisture limitation in the early Holocene. A 200-year reconstruction was developed based on two tree ring proxies, 13C discrimination and maximum latewood density, which together show excellent agreement with the recorded Fairbanks average May through August temperatures. The first half of the 20th century is characterized by the coolest summers of the 200 year period of reconstruction, while the latter part of the 20th century, particularly from 1974 onward, is characterized by some of the warmest summers of the 200 year period. Mid-19th century summer temperatures reconstruct to be as warm as the latter part of the 20th century, which is inconsistent with reconstructions of other regions. It seems likely, based on current information, that these inconsistencies may be real and may reflect regional synoptic conditions unique to interior Alaska. Distinctive decadal scale regimes were identified throughout the record"--Leaf iii.
Book Synopsis Quaternary Glacier Fluctuations in the Chigmit Mountains, Alaska by : Margaret Marie Fritschen
Download or read book Quaternary Glacier Fluctuations in the Chigmit Mountains, Alaska written by Margaret Marie Fritschen and published by . This book was released on 1995 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
