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Author: Daniel Baggenstos
Publisher:
ISBN: 9781321661910
Category :
Languages : en
Pages : 134
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Book Description
The aim of this dissertation is twofold, to develop a new ice sheet margin site on Taylor Glacier as a paleo-climate archive, and to resolve the controversy of the Taylor Dome chronology. The motivation for the former is that ice from deep ice core drilling projects is a precious commodity because only a finite amount of it is available from each core. This precludes measurements of trace constituents that need large sample sizes. Ice margin sites can provide an ice archive that complements the deep drilling efforts. We present a suite of gas measurements from Taylor Glacier, Antarctica, that allow us to date the outcropping ice. We find that ice from the last glacial cycle is exposed at the glacier surface over tens of kilometers. Every climatic interval of the last 125,000 years has been identified, from the penultimate interglacial to the Holocene, laying the foundation for future work. The age of the ice generally increases as one moves down-glacier, but at most locations the across flow age gradient is at least a magnitude larger. We have developed a high resolution age model for an across flow transect covering 50,000 to 8,000 years ago, that offers the chance to study the Last Glacial Maximum and the deglaciation in detail. We also describe and interpret large scale folding observed in the stratigraphy that can provide information on the deformation history. The second focus of this dissertation is to revisit the Taylor Dome chronology, which is at the center of a controversial finding suggesting a direct link of Taylor Dome climate and changes happening in the North Atlantic during the deglaciation. We use measurements of calcium and H2O isotopes in a true horizontal ice core from Taylor Glacier to show unambiguously that the Taylor Dome area temperature history is synchronous with the warming observed in other Antarctic ice cores, and not with North Atlantic records. We also find that the accumulation rate during the Last Glacial Maximum was extremely low, the overestimation of which led to the error in the original time scale. There is evidence from noble gas isotopic composition that a substantial convective zone formed during the same period. We present a new Taylor Dome time scale to replace the now obsolete original Taylor Dome chronology.
Author: Daniel Baggenstos
Publisher:
ISBN: 9781321661910
Category :
Languages : en
Pages : 134
Get Book Here
Book Description
The aim of this dissertation is twofold, to develop a new ice sheet margin site on Taylor Glacier as a paleo-climate archive, and to resolve the controversy of the Taylor Dome chronology. The motivation for the former is that ice from deep ice core drilling projects is a precious commodity because only a finite amount of it is available from each core. This precludes measurements of trace constituents that need large sample sizes. Ice margin sites can provide an ice archive that complements the deep drilling efforts. We present a suite of gas measurements from Taylor Glacier, Antarctica, that allow us to date the outcropping ice. We find that ice from the last glacial cycle is exposed at the glacier surface over tens of kilometers. Every climatic interval of the last 125,000 years has been identified, from the penultimate interglacial to the Holocene, laying the foundation for future work. The age of the ice generally increases as one moves down-glacier, but at most locations the across flow age gradient is at least a magnitude larger. We have developed a high resolution age model for an across flow transect covering 50,000 to 8,000 years ago, that offers the chance to study the Last Glacial Maximum and the deglaciation in detail. We also describe and interpret large scale folding observed in the stratigraphy that can provide information on the deformation history. The second focus of this dissertation is to revisit the Taylor Dome chronology, which is at the center of a controversial finding suggesting a direct link of Taylor Dome climate and changes happening in the North Atlantic during the deglaciation. We use measurements of calcium and H2O isotopes in a true horizontal ice core from Taylor Glacier to show unambiguously that the Taylor Dome area temperature history is synchronous with the warming observed in other Antarctic ice cores, and not with North Atlantic records. We also find that the accumulation rate during the Last Glacial Maximum was extremely low, the overestimation of which led to the error in the original time scale. There is evidence from noble gas isotopic composition that a substantial convective zone formed during the same period. We present a new Taylor Dome time scale to replace the now obsolete original Taylor Dome chronology.
Author: David J. Drewry
Publisher: Princeton University Press
ISBN: 0691237913
Category : History
Languages : en
Pages : 448
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Book Description
"As soon as humans spied and later set foot on the remote Antarctic continent in the early nineteenth century, they became aware of its ice cover, and desired to learn about its extent, shape, thickness, and behavior. In this book, David Drewry-glaciologist and former Director of the Scott Polar Research Institute-recounts the science and history of a ground-breaking time in recent Antarctic geophysical exploration, in which scientists were finally able to "see" through the Antarctic ice sheet and take its measure. From the mid-1960s to the mid-1980s, scientists' ability to peer beneath the Antarctic ice sheet and map its thickness was revolutionized by the technology, techniques, and exploratory campaigns of the Radio Echo Sounding Programme, conducted by the Scott Polar Research Institute at Cambridge in the UK. The exploratory radar mapping campaigns of this ambitious research program were largely accomplished during the Cold War, as interest and concern in global climate change were just emerging. To those involved in this research and fieldwork, it was evident that the environment of the planet was indeed changing, and that the great ice masses of Antarctica and Greenland, and their evolving stability and behavior, would feature significantly in understanding the future of our world. This book gives an account of the Radio Echo Sounding Programme, describing the scientific background, goals, various scientific, human, political, and natural challenges, and discoveries of the research program. It follows the twists and turns of operating in a remote and hostile region, where detailed and exact planning and preparations were constantly at risk of disruption by bad weather, mechanical and electronic breakdowns, aircraft crashes, and human frailty. It also highlights the strong international cooperation that occurred in Antarctica, during this contentious time in history, speaking to the importance of the 1961 Antarctic Treaty as well as the necessity of working together to tackle problems of global significance"--
Author: John D. Castello
Publisher: Princeton University Press
ISBN: 9780691074757
Category : Science
Languages : en
Pages : 348
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Book Description
Based on a National Science Foundation-sponsored symposium organized by the editors in 2001, it comprises twenty chapters by internationally renowned scientists, including Russian experts whose decades of work has been rarely available in English."--Jacket.
Author: Golriz Golkar
Publisher:
ISBN: 9781398255654
Category :
Languages : en
Pages : 0
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Book Description
Author: Jules M. Blais
Publisher: Springer
ISBN: 940179541X
Category : Technology & Engineering
Languages : en
Pages : 515
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Book Description
The human footprint on the global environment now touches every corner of the world. This book explores the myriad ways that environmental archives can be used to study the distribution and long-term trajectories of chemical contaminants. The volume first focuses on reviews that examine the integrity of the historic record, including factors related to hydrology, post-depositional diffusion, and mixing processes. This is followed by a series of chapters dealing with the diverse archives and methodologies available for long-term studies of environmental pollution, such as the use of sediments, ice cores, sclerochronology, and museum specimens.
Author: Thomas K. Bauska
Publisher:
ISBN:
Category : Carbon cycle (Biogeochemistry)
Languages : en
Pages : 209
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Book Description
The exchange of carbon on earth is one of the fundamental processes that sustains life and regulates climate. Since the onset of the Industrial Revolution, the burning of fossil fuels and anthropogenic land conversion have altered the carbon cycle, increasing carbon dioxide in the atmosphere to levels that are unprecedented in the last 800,000 years. This rapid rise in atmospheric carbon dioxide is driving current climate change and further increases are projected to dominate future climate change. However, the fate of the carbon cycle in response to climate change remains uncertain. Insight into how the carbon cycle may change in the future can come from an understanding how it has changed in the past. Key constraints on past carbon cycle variability come from the concentration and stable isotopic composition of atmospheric carbon dioxide recorded in polar ice cores, but reconstructing these histories has been a significant analytical challenge. This thesis presents a new, more precise method for measuring the stable isotopic composition of carbon in carbon dioxide ([delta]13C of CO2) from polar ice. The new method is then used to reconstruct the atmospheric history of [delta]13C of CO2 during the last millennium (~770-1900 C.E.) and last deglaciation (~20,000-10,000 years before present). Previously, methods for measuring the [delta]13C of CO2 had been limited to precision of greater than ±0.05[per mil]. The method presented here combines an ice grater air extraction method and micro-volume equipped dual-inlet mass spectrometer to make high-precision measurements on very small samples of fossil CO2. The precision as determined by replicate analysis is ±0.018[per mil]. The method also provides high-precision measurements of the CO2 (±2 ppm) and N2O (±4 ppb). A new high-resolution (~20 year spacing) record of the [delta]13C of CO2 from 770-1900 C.E is presented that suggests land carbon controlled atmospheric CO2 variability prior to the Industrial Revolution. A deconvolution of the CO2 fluxes to the atmosphere provides a well-constrained estimate of the evolution of land carbon stocks. The relationship between climate and land carbon for this time period constrains future climate-carbon cycle sensitivity, but an additional process affecting land carbon is required to explain the data. This missing process may be related to early anthropogenic land cover change or patterns of drought. A long-standing problem in the field of paleoclimatology is a complete mechanistic understanding of the 80 ppm increase in atmospheric CO2 during the last deglaciation. A horizontal ice core on the Taylor Glacier in Antarctica allowed for the recovery of well-dated, large ice samples spanning the last deglaciation. From this unique archive, a new [delta]13C of CO2 of very high resolution (50-150 year spacing) is reconstructed. A box model of the carbon cycle is used to construct a framework of the evolution of the carbon cycle during deglaciation. During the Last Glacial Maximum, the lower CO2 concentration accompanied by only a minor shift in [delta]13C of CO2 relative to the early Holocene is consistent with a more efficient biological pump in the Southern ocean, limited air-sea gas exchange around Antarctica, and colder ocean temperatures. The temporal evolution of these factors, as informed by timing of proxy data, reconciles the non-linear relationship between CO2 and [delta]13C of CO2 from the Last Glacial Maximum to the pre-Industrial. However, the data also reveal very fast changes in [delta]13C of CO2 that suggest a rapid emission of depleted carbon to the atmosphere on the centennial timescale that is not captured in current models.
Author: D.P. Le Heron
Publisher: Geological Society of London
ISBN: 1786203979
Category : Science
Languages : en
Pages : 289
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Book Description
Understanding the sedimentary and geophysical archive of glaciated margins is a complex task that requires integration and analysis of disparate sedimentological and geophysical data. Their analysis is vital for understanding the dynamics of past ice sheets and how they interact with their neighbouring marine basins, on timescales that cannot be captured by observations of the cryosphere today. As resources, sediments deposited on the inner margins of glaciated shelves also exhibit resource potential where more sand-dominated systems occur, acting as reservoirs for both hydrocarbons and water. This book surveys the full gamut of glaciated margins, from deep time (Neoproterozoic, Ordovician and Carboniferous–Permian) to modern high-latitude margins in Canada and Antarctica. This collection of papers is the first attempt to deliberately do this, allowing not only the similarities and differences between modern and ancient glaciated margins to be explored, but also the wide spectrum of their mechanisms of investigation to be probed. Together, these papers offer a high-resolution, spatially and temporally diverse blueprint of the depositional processes, ice sheet dynamics, and basin architectures of the world’s former glaciated margins; a vital resource in advancing understanding of our present and future marine-terminating ice sheet margins.
Author: Brian M. Fagan
Publisher: Routledge
ISBN: 131735012X
Category :
Languages : en
Pages : 382
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Book Description
Author: Wallace S. Broecker
Publisher:
ISBN:
Category : Climatic changes
Languages : en
Pages : 354
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Book Description
Author: U.S. Geological Survey
Publisher:
ISBN: 9781782662174
Category : Science
Languages : en
Pages : 396
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Book Description
