The TEX86 Paleotemperature Proxy PDF Download

Author: Gordon N. Inglis
Publisher: Cambridge University Press
ISBN: 1108847528
Category : Science
Languages : en
Pages : 51

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Book Description
The TEX86 paleothermometer is based upon the distribution of archaeal membrane lipids ('GDGTs') in marine sediments. GDGTs are ubiquitous, abundant and relatively resistant to degradation; as such, the TEX86 paleothermometer has been used to reconstruct sea surface temperature (SST) during the Cenozoic and early Mesozoic. We review the principles of the TEX86 proxy and developments made over the last two decades. We also discuss its application as a paleotemperature proxy and explore existing challenges and limitations.

Author: Vivien Gornitz
Publisher: Springer Science & Business Media
ISBN: 1402045514
Category : Science
Languages : en
Pages : 1062

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Book Description
One of Springer’s Major Reference Works, this book gives the reader a truly global perspective. It is the first major reference work in its field. Paleoclimate topics covered in the encyclopedia give the reader the capability to place the observations of recent global warming in the context of longer-term natural climate fluctuations. Significant elements of the encyclopedia include recent developments in paleoclimate modeling, paleo-ocean circulation, as well as the influence of geological processes and biological feedbacks on global climate change. The encyclopedia gives the reader an entry point into the literature on these and many other groundbreaking topics.

Author: National Research Council
Publisher: National Academies Press
ISBN: 0309102251
Category : Science
Languages : en
Pages : 160

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Book Description
In response to a request from Congress, Surface Temperature Reconstructions for the Last 2,000 Years assesses the state of scientific efforts to reconstruct surface temperature records for Earth during approximately the last 2,000 years and the implications of these efforts for our understanding of global climate change. Because widespread, reliable temperature records are available only for the last 150 years, scientists estimate temperatures in the more distant past by analyzing "proxy evidence," which includes tree rings, corals, ocean and lake sediments, cave deposits, ice cores, boreholes, and glaciers. Starting in the late 1990s, scientists began using sophisticated methods to combine proxy evidence from many different locations in an effort to estimate surface temperature changes during the last few hundred to few thousand years. This book is an important resource in helping to understand the intricacies of global climate change.

Author: Jennifer Eve Hertzberg
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Paleotemperature proxies enable scientists to reconstruct past ocean temperatures from sediment recovered in deep-sea cores. This dissertation takes an in-depth look at two proxies, Mg/Ca ratios of planktonic foraminifera and the TEX86 index, and applies the Mg/Ca paleothermometer in a novel way to assess past changes in tropical Pacific climate. Chapter II is a reinvestigation of a proposed large salinity effect on Mg/Ca ratios in the foraminifera Globigerinoides ruber based on a recent Atlantic core-top meridional transect study. Shell weight analyses and scanning electron microscopy are used to assess the preservation of similar G. ruber shells used in the core-top study. Shells from the equatorial Atlantic are highly dissolved compared to those from the subtropical gyres, impacting their Mg/Ca-temperatures. When Mg/Ca-temperature calibrations that account for dissolution differences are used, there is no longer an apparent large salinity effect, suggesting that regional differences in preservation, rather than salinity, significantly affect Mg/Ca-temperatures. Chapter III investigates the TEX86 temperature proxy in the eastern Pacific by utilizing Mg/Ca paleothermometry on multiple species of planktonic foraminifera across the Holocene and Last Glacial Maximum (LGM) to determine the recording depth of the TEX86 proxy. Holocene TEX86 temperatures match sea surface temperatures, but during the LGM, there is a cold bias in TEX86 temperatures that are more representative of the upper thermocline. The best explanation for the offset is a decrease in LGM nutrient availability. Therefore, caution should be applied when interpreting TEX86 records based solely on the relationship between core-top/Holocene TEX86 temperatures and modern observational temperatures. Chapter IV reconstructs past changes in the tropical Pacific mean state across Marine Isotope Stage 3 by utilizing Mg/Ca paleothermometry on the thermocline dwelling foraminifera Neogloboquadrina dutertrei from an eastern equatorial Pacific sediment core. The thermocline temperature record reveals interstadials are characterized by a more El Niño-like mean state, with increases in thermocline temperatures up to 6°C. Thermocline warming events are more pronounced from 64-44 kyr when global climate was in a warmer state. From 44-32 kyr, the record shows cooler thermocline temperatures, suggesting a shift to a more La Niña-like mean state, as climate began transitioning into the LGM. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/155637

Author: Gerhard Fischer
Publisher: Springer Science & Business Media
ISBN: 9783540663409
Category : Science
Languages : en
Pages : 768

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Book Description
Paleoceanographic proxies provide infonnation for reconstructions of the past, including climate changes, global and regional oceanography, and the cycles of biochemical components in the ocean. These prox ies are measurable descriptors for desired but unobservable environmental variables such as tempera ture, salinity, primary productivity, nutrient content, or surface-water carbon dioxide concentrations. The proxies are employed in a manner analogous to oceanographic methods. The water masses are first characterized according to their specific physical and chemical properties, and then related to particular assemblages of certain organisms or to particular element or isotope distributions. We have a long-standing series of proven proxies available. Marine microfossil assemblages, for instance, are employed to reconstruct surface-water temperatures. The calcareous shells of planktonic and benthic microorgan isms contain a wealth of paleoceanographic information in their isotopic and elemental compositions. Stable oxygen isotope measurements are used to detennine ice volume, and MglCa ratios are related to water temperatures, to cite a few examples. Organic material may also provide valuable infonnation, e. g. , about past productivity conditions. Studying the stable carbon isotope composition of bulk organic matter or individual marine organic components may provide a measure of past surface-water CO 2 conditions within the bounds of certain assumptions. Within the scope of paleoceanographic investigations, the existing proxies are continuously evolving and improving, while new proxies are being studied and developed. The methodology is improved by analysis of samples from the water column and surface sediments, and through laboratory experiments.

Author: Heinrich D Holland
Publisher: Academic Press
ISBN: 0080967116
Category : Science
Languages : en
Pages : 750

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Book Description
After the discovery that elements were commonly composed of isotopes, there developed a range of studies of the variability of isotopic compositions in Earth materials, which was able to add to our understanding of Earth processes and history. This collection of chapters from the Treatise on Geochemistry describes the range of isotopic studies. The chapters are grouped into the following categories: light stable isotopes, radiogenic tracers, noble gases and radioactive tracers. The first three groups depend on mass spectrometric measurements. The section on radioactive tracers employs both radioactive counting techniques and the newly developed accelerator mass spectrometric techniques. Comprehensive, interdisciplinary and authoritative content selected by leading subject experts Robust illustrations, figures and tables Affordably priced sampling of content from the full Treatise on Geochemistry

Author: National Research Council
Publisher: National Academies Press
ISBN: 0309209196
Category : Science
Languages : en
Pages : 153

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Book Description
There is little dispute within the scientific community that humans are changing Earth's climate on a decadal to century time-scale. By the end of this century, without a reduction in emissions, atmospheric CO2 is projected to increase to levels that Earth has not experienced for more than 30 million years. As greenhouse gas emissions propel Earth toward a warmer climate state, an improved understanding of climate dynamics in warm environments is needed to inform public policy decisions. In Understanding Earth's Deep Past, the National Research Council reports that rocks and sediments that are millions of years old hold clues to how the Earth's future climate would respond in an environment with high levels of atmospheric greenhouse gases. Understanding Earth's Deep Past provides an assessment of both the demonstrated and underdeveloped potential of the deep-time geologic record to inform us about the dynamics of the global climate system. The report describes past climate changes, and discusses potential impacts of high levels of atmospheric greenhouse gases on regional climates, water resources, marine and terrestrial ecosystems, and the cycling of life-sustaining elements. While revealing gaps in scientific knowledge of past climate states, the report highlights a range of high priority research issues with potential for major advances in the scientific understanding of climate processes. This proposed integrated, deep-time climate research program would study how climate responded over Earth's different climate states, examine how climate responds to increased atmospheric carbon dioxide and other greenhouse gases, and clarify the processes that lead to anomalously warm polar and tropical regions and the impact on marine and terrestrial life. In addition to outlining a research agenda, Understanding Earth's Deep Past proposes an implementation strategy that will be an invaluable resource to decision-makers in the field, as well as the research community, advocacy organizations, government agencies, and college professors and students.

Author: Hodaka Kawahata
Publisher: Elsevier
ISBN: 0080469418
Category : Science
Languages : en
Pages : 531

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Book Description
To understand the global warming mechanism, global mapping of primary production was carried out under the GCMAPS program. The program was concerned with marine and terrestrial environmental changes, which affect carbon cycle on the regional and global scales. On the regional scale, warm phase of ENSO (El Niño / Southern Oscillation) has been shown to affect economic activities in many countries. The keyword for understanding mechanism of global warming is ‘primary productivity’. The earth observation satellites (EOS) like the ADEOS of Japan, and the SeaWiFS, Sea Star and Terra of the U.S.A. provided much required data for modeling and verification of primary production estimates on both land and ocean. The knowledge gained during the GCMAPS program has been documented in this book. Interpretation of the data suggests that global warming, which causes temperature and sea level rise, and changes in climate and ecosystems, is likely to have the largest influence on mankind. The first half of this book discuss changes in marine environments. Physical and chemical oceanographic properties of the equatorial Pacific and Indian Oceans are presented. Changes in partial pressure of carbon dioxide, flux and composition of settling particles and biological communities in the surface ocean have also been discussed. In addition to this, over hundred years of environmental records based upon coral skeletons are presented. Estimations of primary production and its utilization in validating satellite imagery data were conducted in the western North Pacific. Primary productivity estimates based upon the validated satellite imagery are presented on the global scale. Climate change modeling of primary production in global oceans is also presented. The latter half of this book deals with changes in terrestrial environments. Primary productivity estimates for different types of ecosystems (e.g., forest, grassland) are presented together with soil carbon dynamics. Also, biomass and productivity estimation and environmental monitoring based upon remote sensing techniques are presented with a model analysis of the relationship between climate perturbations and carbon budget anomalies in global terrestrial ecosystems. This book elucidates integrated aspects of the global carbon cycle involving marine and terrestrial environments. Discusses a current understanding of the biogeochemical processes on land and ocean Provides global mapping of primary production based on satellite imagery data and modelling Presents the latest interpretations of relationships between carbon cycle and climatic change

Author:
Publisher: Newnes
ISBN: 0080983006
Category : Science
Languages : en
Pages : 14787

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Book Description
This extensively updated new edition of the widely acclaimed Treatise on Geochemistry has increased its coverage beyond the wide range of geochemical subject areas in the first edition, with five new volumes which include: the history of the atmosphere, geochemistry of mineral deposits, archaeology and anthropology, organic geochemistry and analytical geochemistry. In addition, the original Volume 1 on "Meteorites, Comets, and Planets" was expanded into two separate volumes dealing with meteorites and planets, respectively. These additions increased the number of volumes in the Treatise from 9 to 15 with the index/appendices volume remaining as the last volume (Volume 16). Each of the original volumes was scrutinized by the appropriate volume editors, with respect to necessary revisions as well as additions and deletions. As a result, 27% were republished without major changes, 66% were revised and 126 new chapters were added. In a many-faceted field such as Geochemistry, explaining and understanding how one sub-field relates to another is key. Instructors will find the complete overviews with extensive cross-referencing useful additions to their course packs and students will benefit from the contextual organization of the subject matter Six new volumes added and 66% updated from 1st edition. The Editors of this work have taken every measure to include the many suggestions received from readers and ensure comprehensiveness of coverage and added value in this 2nd edition The esteemed Board of Volume Editors and Editors-in-Chief worked cohesively to ensure a uniform and consistent approach to the content, which is an amazing accomplishment for a 15-volume work (16 volumes including index volume)!

Author: H. Elderfield
Publisher: Elsevier
ISBN: 9780080451015
Category : Business & Economics
Languages : en
Pages : 668

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Book Description
The Treatise on Geochemistry is the first work providing a comprehensive, integrated summary of the present state of geochemistry. It deals with all the major subjects in the field, ranging from the chemistry of the solar system to environmental geochemistry. The Treatise on Geochemistry has drawn on the expertise of outstanding scientists throughout the world, creating the reference work in geochemistry for the next decade. Each volume consists of fifteen to twenty-five chapters written by recognized authorities in their fields, and chosen by the Volume Editors in consultation with the Executive Editors. Particular emphasis has been placed on integrating the subject matter of the individual chapters and volumes. Elsevier also offers the Treatise on Geochemistry in electronic format via the online platform ScienceDirect, the most comprehensive database of academic research on the Internet today, enhanced by a suite of sophisticated linking, searching and retrieval tools.