Emerging Patterns in Proterozoic Lipid Biomarker Records

Emerging Patterns in Proterozoic Lipid Biomarker Records

Author: Gordon D. Love

Publisher: Cambridge University Press

Published: 2021-03-25

Total Pages: 82

ISBN-13: 1108847536

DOWNLOAD EBOOK

Diverse and abundant lipid biomarker assemblages have been reported from a variety of Proterozoic marine environments from the careful analysis of well-preserved rocks and oils. These molecular biosignatures have provided unique insights into the communities and the environmental conditions which characterized the Proterozoic marine biosphere. We summarize some of the major temporal patterns evident in Proterozoic lipid biomarkers found to date, whilst emphasizing the scale of local heterogeneity found within Neoproterozoic oceans from region to region, and their relationship with the evolving ecological, climatic and ocean/atmospheric redox conditions. Short commentaries on a selection of papers published from the last 15 years of biomarker literature are given. The focus here is on key studies, highlighted for further reading, which have helped to better constrain the timing of the ecological expansion of eukaryotes in Proterozoic oceans or which have impacted on our knowledge of the biological sources of Proterozoic biomarkers.


Book Synopsis Emerging Patterns in Proterozoic Lipid Biomarker Records by : Gordon D. Love

Download or read book Emerging Patterns in Proterozoic Lipid Biomarker Records written by Gordon D. Love and published by Cambridge University Press. This book was released on 2021-03-25 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diverse and abundant lipid biomarker assemblages have been reported from a variety of Proterozoic marine environments from the careful analysis of well-preserved rocks and oils. These molecular biosignatures have provided unique insights into the communities and the environmental conditions which characterized the Proterozoic marine biosphere. We summarize some of the major temporal patterns evident in Proterozoic lipid biomarkers found to date, whilst emphasizing the scale of local heterogeneity found within Neoproterozoic oceans from region to region, and their relationship with the evolving ecological, climatic and ocean/atmospheric redox conditions. Short commentaries on a selection of papers published from the last 15 years of biomarker literature are given. The focus here is on key studies, highlighted for further reading, which have helped to better constrain the timing of the ecological expansion of eukaryotes in Proterozoic oceans or which have impacted on our knowledge of the biological sources of Proterozoic biomarkers.

Sr Isotopes in Seawater

Sr Isotopes in Seawater

Author: B. Lynn Ingram

Publisher: Cambridge University Press

Published: 2022-03-31

Total Pages: 51

ISBN-13: 1108998356

DOWNLOAD EBOOK

Studies of Sr isotopic composition of thousands of samples of marine sediments and fossils have yielded a curve of 87Sr/86Sr versus age for seawater Sr that extends back to 1 billion years. The ratio has fluctuated with large amplitude during this time period, and because the ratio is always uniform in the oceans globally at any one time, it is useful as a stratigraphic correlation and age-dating tool. The ratio also appears to reflect major tectonic and climatic events in Earth history and hence provides clues as to the causes, timing, and consequences of those events. The seawater 87Sr/86Sr ratio is generally high during periods marked by continent-continent collisions, and lower when continental topography is subdued, and seafloor generation rates are high. There is evidence that major shifts in the seawater ratio can be ascribed to specific orogenic events and correlate with large shifts in global climate.


Book Synopsis Sr Isotopes in Seawater by : B. Lynn Ingram

Download or read book Sr Isotopes in Seawater written by B. Lynn Ingram and published by Cambridge University Press. This book was released on 2022-03-31 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies of Sr isotopic composition of thousands of samples of marine sediments and fossils have yielded a curve of 87Sr/86Sr versus age for seawater Sr that extends back to 1 billion years. The ratio has fluctuated with large amplitude during this time period, and because the ratio is always uniform in the oceans globally at any one time, it is useful as a stratigraphic correlation and age-dating tool. The ratio also appears to reflect major tectonic and climatic events in Earth history and hence provides clues as to the causes, timing, and consequences of those events. The seawater 87Sr/86Sr ratio is generally high during periods marked by continent-continent collisions, and lower when continental topography is subdued, and seafloor generation rates are high. There is evidence that major shifts in the seawater ratio can be ascribed to specific orogenic events and correlate with large shifts in global climate.

Magnesium Isotopes

Magnesium Isotopes

Author: Edward T. Tipper

Publisher: Cambridge University Press

Published: 2022-03-03

Total Pages: 34

ISBN-13: 1108998542

DOWNLOAD EBOOK

Magnesium is a major constituent in silicate and carbonate minerals, the hydrosphere and the biosphere. Magnesium is constantly cycled between these reservoirs. Since each of the major planetary reservoirs of magnesium have different magnesium isotope ratios, there is scope to use magnesium isotope ratios to trace 1) the processes that cycle Magnesium at a spatial scales from the entire planet to microscopic and 2) the relative fluxes between these reservoirs. This review summarises some of the key motivations, successes and challenges facing the use of magnesium isotopes to construct a budget of seawater magnesium, present and past.


Book Synopsis Magnesium Isotopes by : Edward T. Tipper

Download or read book Magnesium Isotopes written by Edward T. Tipper and published by Cambridge University Press. This book was released on 2022-03-03 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnesium is a major constituent in silicate and carbonate minerals, the hydrosphere and the biosphere. Magnesium is constantly cycled between these reservoirs. Since each of the major planetary reservoirs of magnesium have different magnesium isotope ratios, there is scope to use magnesium isotope ratios to trace 1) the processes that cycle Magnesium at a spatial scales from the entire planet to microscopic and 2) the relative fluxes between these reservoirs. This review summarises some of the key motivations, successes and challenges facing the use of magnesium isotopes to construct a budget of seawater magnesium, present and past.

Local and Global Controls on Carbon Isotope Chemostratigraphy

Local and Global Controls on Carbon Isotope Chemostratigraphy

Author: Anne-Sofie Ahm

Publisher: Cambridge University Press

Published: 2022-03-31

Total Pages: 48

ISBN-13: 100903362X

DOWNLOAD EBOOK

Over million-year timescales, the geologic cycling of carbon controls long-term climate and the oxidation of Earth's surface. Inferences about the carbon cycle can be made from time series of carbon isotopic ratios measured from sedimentary rocks. The foundational assumption for carbon isotope chemostratigraphy is that carbon isotope values reflect dissolved inorganic carbon in a well-mixed ocean in equilibrium with the atmosphere. However, when applied to shallow-water platform environments, where most ancient carbonates preserved in the geological record formed, recent research has documented the importance of considering both local variability in surface water chemistry and diagenesis. These findings demonstrate that carbon isotope chemostratigraphy of platform carbonate rarely represent the average carbonate sink or directly records changes in the composition of global seawater. Understanding what causes local variability in shallow-water settings, and what this variability might reveal about global boundary conditions, are vital questions for the next generation of carbon isotope chemostratigraphers.


Book Synopsis Local and Global Controls on Carbon Isotope Chemostratigraphy by : Anne-Sofie Ahm

Download or read book Local and Global Controls on Carbon Isotope Chemostratigraphy written by Anne-Sofie Ahm and published by Cambridge University Press. This book was released on 2022-03-31 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over million-year timescales, the geologic cycling of carbon controls long-term climate and the oxidation of Earth's surface. Inferences about the carbon cycle can be made from time series of carbon isotopic ratios measured from sedimentary rocks. The foundational assumption for carbon isotope chemostratigraphy is that carbon isotope values reflect dissolved inorganic carbon in a well-mixed ocean in equilibrium with the atmosphere. However, when applied to shallow-water platform environments, where most ancient carbonates preserved in the geological record formed, recent research has documented the importance of considering both local variability in surface water chemistry and diagenesis. These findings demonstrate that carbon isotope chemostratigraphy of platform carbonate rarely represent the average carbonate sink or directly records changes in the composition of global seawater. Understanding what causes local variability in shallow-water settings, and what this variability might reveal about global boundary conditions, are vital questions for the next generation of carbon isotope chemostratigraphers.

Molybdenum as a Paleoredox Proxy

Molybdenum as a Paleoredox Proxy

Author: Stephan R. Hlohowskyj

Publisher: Cambridge University Press

Published: 2021-09-09

Total Pages: 57

ISBN-13: 1009002260

DOWNLOAD EBOOK

Molybdenum (Mo) is a widely used trace metal for investigating redox conditions. However, unanswered questions remain that concentration and bulk isotopic analysis cannot specially answer. Improvements can be made by combining new geochemical techniques to traditional methods of Mo analysis. In this Element, we propose a refinement of Mo geochemistry within aquatic systems, ancient rocks, and modern sediments through molecular geochemistry (systematically combining concentration, isotope ratio, elemental mapping, and speciation analyses). Specifically, to intermediate sulfide concentrations governing Mo behavior below the 'switch-point' and dominant sequestration pathways in low oxygen conditions. The aim of this work is to 1) aid and improve the breadth of Mo paleoproxy interpretations by considering Mo speciation and 2) address outstanding research gaps concerning Mo systematics (cycling, partitioning, sequestration, etc.). The Mo paleoproxy has potential to solve ever complex research questions. By using molecular geochemical recommendations, improved Mo paleoproxy interpretations and reconstruction can be achieved.


Book Synopsis Molybdenum as a Paleoredox Proxy by : Stephan R. Hlohowskyj

Download or read book Molybdenum as a Paleoredox Proxy written by Stephan R. Hlohowskyj and published by Cambridge University Press. This book was released on 2021-09-09 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molybdenum (Mo) is a widely used trace metal for investigating redox conditions. However, unanswered questions remain that concentration and bulk isotopic analysis cannot specially answer. Improvements can be made by combining new geochemical techniques to traditional methods of Mo analysis. In this Element, we propose a refinement of Mo geochemistry within aquatic systems, ancient rocks, and modern sediments through molecular geochemistry (systematically combining concentration, isotope ratio, elemental mapping, and speciation analyses). Specifically, to intermediate sulfide concentrations governing Mo behavior below the 'switch-point' and dominant sequestration pathways in low oxygen conditions. The aim of this work is to 1) aid and improve the breadth of Mo paleoproxy interpretations by considering Mo speciation and 2) address outstanding research gaps concerning Mo systematics (cycling, partitioning, sequestration, etc.). The Mo paleoproxy has potential to solve ever complex research questions. By using molecular geochemical recommendations, improved Mo paleoproxy interpretations and reconstruction can be achieved.

Barium Isotopes

Barium Isotopes

Author: Tristan J. Horner

Publisher: Cambridge University Press

Published: 2021-04-22

Total Pages: 44

ISBN-13: 1108857515

DOWNLOAD EBOOK

In the modern marine environment, barium isotope (δ138Ba) variations are primarily driven by barite cycling—barite incorporates 'light' Ba isotopes from solution, rendering the residual Ba reservoir enriched in 'heavy' Ba isotopes by a complementary amount. Since the processes of barite precipitation and dissolution are vertically segregated and spatially heterogeneous, barite cycling drives systematic variations in the barium isotope composition of seawater and sediments. This Element examines these variations; evaluates their global, regional, local, and geological controls; and, explores how δ138Ba can be exploited to constrain the origin of enigmatic sedimentary sulfates and to study marine biogeochemistry over Earth's history.


Book Synopsis Barium Isotopes by : Tristan J. Horner

Download or read book Barium Isotopes written by Tristan J. Horner and published by Cambridge University Press. This book was released on 2021-04-22 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the modern marine environment, barium isotope (δ138Ba) variations are primarily driven by barite cycling—barite incorporates 'light' Ba isotopes from solution, rendering the residual Ba reservoir enriched in 'heavy' Ba isotopes by a complementary amount. Since the processes of barite precipitation and dissolution are vertically segregated and spatially heterogeneous, barite cycling drives systematic variations in the barium isotope composition of seawater and sediments. This Element examines these variations; evaluates their global, regional, local, and geological controls; and, explores how δ138Ba can be exploited to constrain the origin of enigmatic sedimentary sulfates and to study marine biogeochemistry over Earth's history.

Iron Formations as Palaeoenvironmental Archives

Iron Formations as Palaeoenvironmental Archives

Author: Kaarel Mänd

Publisher: Cambridge University Press

Published: 2022-01-20

Total Pages: 66

ISBN-13: 1009002279

DOWNLOAD EBOOK

Ancient iron formations - iron and silica-rich chemical sedimentary rocks that formed throughout the Precambrian eons - provide a significant part of the evidence for the modern scientific understanding of palaeoenvironmental conditions in Archaean (4.0–2.5 billion years ago) and Proterozoic (2.5–0.539 billion years ago) times. Despite controversies regarding their formation mechanisms, iron formations are a testament to the influence of the Precambrian biosphere on early ocean chemistry. As many iron formations are pure chemical sediments that reflect the composition of the waters from which they precipitated, they can also serve as nuanced geochemical archives for the study of ancient marine temperatures, redox states, and elemental cycling, if proper care is taken to understand their sedimentological context.


Book Synopsis Iron Formations as Palaeoenvironmental Archives by : Kaarel Mänd

Download or read book Iron Formations as Palaeoenvironmental Archives written by Kaarel Mänd and published by Cambridge University Press. This book was released on 2022-01-20 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ancient iron formations - iron and silica-rich chemical sedimentary rocks that formed throughout the Precambrian eons - provide a significant part of the evidence for the modern scientific understanding of palaeoenvironmental conditions in Archaean (4.0–2.5 billion years ago) and Proterozoic (2.5–0.539 billion years ago) times. Despite controversies regarding their formation mechanisms, iron formations are a testament to the influence of the Precambrian biosphere on early ocean chemistry. As many iron formations are pure chemical sediments that reflect the composition of the waters from which they precipitated, they can also serve as nuanced geochemical archives for the study of ancient marine temperatures, redox states, and elemental cycling, if proper care is taken to understand their sedimentological context.

Petroleum Abstracts

Petroleum Abstracts

Author:

Publisher:

Published: 1992

Total Pages: 1716

ISBN-13:

DOWNLOAD EBOOK


Book Synopsis Petroleum Abstracts by :

Download or read book Petroleum Abstracts written by and published by . This book was released on 1992 with total page 1716 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Chemical Biomarkers in Aquatic Ecosystems

Chemical Biomarkers in Aquatic Ecosystems

Author: Thomas S. Bianchi

Publisher: Princeton University Press

Published: 2011-02-28

Total Pages: 417

ISBN-13: 1400839106

DOWNLOAD EBOOK

This textbook provides a unique and thorough look at the application of chemical biomarkers to aquatic ecosystems. Defining a chemical biomarker as a compound that can be linked to particular sources of organic matter identified in the sediment record, the book indicates that the application of these biomarkers for an understanding of aquatic ecosystems consists of a biogeochemical approach that has been quite successful but underused. This book offers a wide-ranging guide to the broad diversity of these chemical biomarkers, is the first to be structured around the compounds themselves, and examines them in a connected and comprehensive way. This timely book is appropriate for advanced undergraduate and graduate students seeking training in this area; researchers in biochemistry, organic geochemistry, and biogeochemistry; researchers working on aspects of organic cycling in aquatic ecosystems; and paleoceanographers, petroleum geologists, and ecologists. Provides a guide to the broad diversity of chemical biomarkers in aquatic environments The first textbook to be structured around the compounds themselves Describes the structure, biochemical synthesis, analysis, and reactivity of each class of biomarkers Offers a selection of relevant applications to aquatic systems, including lakes, rivers, estuaries, oceans, and paleoenvironments Demonstrates the utility of using organic molecules as tracers of processes occurring in aquatic ecosystems, both modern and ancient


Book Synopsis Chemical Biomarkers in Aquatic Ecosystems by : Thomas S. Bianchi

Download or read book Chemical Biomarkers in Aquatic Ecosystems written by Thomas S. Bianchi and published by Princeton University Press. This book was released on 2011-02-28 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook provides a unique and thorough look at the application of chemical biomarkers to aquatic ecosystems. Defining a chemical biomarker as a compound that can be linked to particular sources of organic matter identified in the sediment record, the book indicates that the application of these biomarkers for an understanding of aquatic ecosystems consists of a biogeochemical approach that has been quite successful but underused. This book offers a wide-ranging guide to the broad diversity of these chemical biomarkers, is the first to be structured around the compounds themselves, and examines them in a connected and comprehensive way. This timely book is appropriate for advanced undergraduate and graduate students seeking training in this area; researchers in biochemistry, organic geochemistry, and biogeochemistry; researchers working on aspects of organic cycling in aquatic ecosystems; and paleoceanographers, petroleum geologists, and ecologists. Provides a guide to the broad diversity of chemical biomarkers in aquatic environments The first textbook to be structured around the compounds themselves Describes the structure, biochemical synthesis, analysis, and reactivity of each class of biomarkers Offers a selection of relevant applications to aquatic systems, including lakes, rivers, estuaries, oceans, and paleoenvironments Demonstrates the utility of using organic molecules as tracers of processes occurring in aquatic ecosystems, both modern and ancient

The Iron Speciation Paleoredox Proxy

The Iron Speciation Paleoredox Proxy

Author: Simon W. Poulton

Publisher: Cambridge University Press

Published: 2021-03-04

Total Pages: 34

ISBN-13: 1108848591

DOWNLOAD EBOOK

In one form or another, iron speciation has had a long history as a paleoredox proxy. The technique has been refined considerably over the years, and the most recent scheme is unique in its potential to distinguish three major oceanic redox states - oxygenated, ferruginous and euxinic. This Element covers the theory behind the proxy, methods involved in applying the technique, and potential complications in interpreting Fe speciation data. A series of case studies are also provided, which highlight how more advanced consideration of the data, often in concert with other techniques, can provide unprecedented insight into the redox state of ancient oceans.


Book Synopsis The Iron Speciation Paleoredox Proxy by : Simon W. Poulton

Download or read book The Iron Speciation Paleoredox Proxy written by Simon W. Poulton and published by Cambridge University Press. This book was released on 2021-03-04 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: In one form or another, iron speciation has had a long history as a paleoredox proxy. The technique has been refined considerably over the years, and the most recent scheme is unique in its potential to distinguish three major oceanic redox states - oxygenated, ferruginous and euxinic. This Element covers the theory behind the proxy, methods involved in applying the technique, and potential complications in interpreting Fe speciation data. A series of case studies are also provided, which highlight how more advanced consideration of the data, often in concert with other techniques, can provide unprecedented insight into the redox state of ancient oceans.