The Geologic Time Scale 2012

Author by : F M Gradstein
Languange : en
Publisher by : Elsevier
Format Available : PDF, ePub, Mobi
Total Read : 81
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Description : The Geologic Time Scale 2012, winner of a 2012 PROSE Award Honorable Mention for Best Multi-volume Reference in Science from the Association of American Publishers, is the framework for deciphering the history of our planet Earth. The authors have been at the forefront of chronostratigraphic research and initiatives to create an international geologic time scale for many years, and the charts in this book present the most up-to-date, international standard, as ratified by the International Commission on Stratigraphy and the International Union of Geological Sciences. This 2012 geologic time scale is an enhanced, improved and expanded version of the GTS2004, including chapters on planetary scales, the Cryogenian-Ediacaran periods/systems, a prehistory scale of human development, a survey of sequence stratigraphy, and an extensive compilation of stable-isotope chemostratigraphy. This book is an essential reference for all geoscientists, including researchers, students, and petroleum and mining professionals. The presentation is non-technical and illustrated with numerous colour charts, maps and photographs. The book also includes a detachable wall chart of the complete time scale for use as a handy reference in the office, laboratory or field. The most detailed international geologic time scale available that contextualizes information in one single reference for quick desktop access Gives insights in the construction, strengths, and limitations of the geological time scale that greatly enhances its function and its utility Aids understanding by combining with the mathematical and statistical methods to scaled composites of global succession of events Meets the needs of a range of users at various points in the workflow (researchers extracting linear time from rock records, students recognizing the geologic stage by their content)


Geologic Time Scale 2020

Author by : Felix M. Gradstein
Languange : en
Publisher by : Elsevier
Format Available : PDF, ePub, Mobi
Total Read : 98
Total Download : 877
File Size : 43,9 Mb
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Description : Geologic Time Scale 2020 contains contributions from 80 leading scientists who present syntheses in an easy-to-understand format that includes numerous color charts, maps and photographs. In addition to detailed overviews of chronostratigraphy, evolution, geochemistry, sequence stratigraphy and planetary geology, the GTS2020 volumes have separate chapters on each geologic period with compilations of the history of divisions, the current GSSPs (global boundary stratotypes), detailed bio-geochem-sequence correlation charts, and derivation of the age models. The authors are on the forefront of chronostratigraphic research and initiatives surrounding the creation of an international geologic time scale. The included charts present the most up-to-date, international standard as ratified by the International Commission on Stratigraphy and the International Union of Geological Sciences. As the framework for deciphering the history of our planet Earth, this book is essential for practicing Earth Scientists and academics. Completely updated time scale Provides the most detailed international geologic time scale available that compiles and synthesize information in one reference Gives insights on the construction, strengths and limitations of the geological time scale that greatly enhances its function and its utility


Geologic Time Scale 2020

Author by : Felix M. Gradstein
Languange : en
Publisher by : Elsevier
Format Available : PDF, ePub, Mobi
Total Read : 92
Total Download : 871
File Size : 44,9 Mb
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Description : Geologic Time Scale 2020 contains contributions from leading scientists, with information presented in an easy-to-understand way including numerous color charts, maps, and photographs. Including recent information from such projects as GTSNext, Earth Time Europe, and Chronos, this updated edition explains in detail how and why the time scale is being updated and offers expanded coverage of paleontology and stratigraphy. Twelve mini chapters in Geologic Time Scale 2020 address Evolution and Biostratigraphy in key (micro-) fossil groups. These chapters assist readers of the Geological Period chapters to better understand and appreciate the role played by paleontology in describing and understanding life on Earth in Deep Time. The authors of Geologic Time Scale 2020 have been at the forefront of chronostratigraphic research and initiatives to create an international geologic time scale for many years, and the charts in this book present the most up-to-date, international chronostratigraphic standard as ratified by the International Commission on Stratigraphy and the International Union of Geological Sciences. As the framework for deciphering the history of our planet Earth, this book is essential for practicing Earth Scientists and academics. The most detailed international geologic time scale available that contextualizes information in one reference Gives insights in the construction, strengths, and limitations of the geological time scale that greatly enhances its function and its utility Aids understanding by combining mathematical and statistical methods to create scaled composites of the global succession of events Meets the needs of a range of users at various points in the workflow (researchers extracting linear time from rock records, students recognizing the geologic stage by their content) Completely updated time scale including research from projects such as GTSNext, Earth Time Europe, and Chronos Addresses Evolution and Biostratigraphy in key (micro-) fossil groups with atlas style range charts which provide detailed explanation of the index fossils and key zonations building the stratigraphic framework of the Geological Periods


The Geologic Time Scale 2012 2 Volume Set

Author by : F. M. Gradstein
Languange : en
Publisher by : Elsevier
Format Available : PDF, ePub, Mobi
Total Read : 54
Total Download : 579
File Size : 41,8 Mb
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Description : The Geologic Time Scale 2012, winner of a 2012 PROSE Award Honorable Mention for Best Multi-volume Reference in Science from the Association of American Publishers, is the framework for deciphering the history of our planet Earth. The authors have been at the forefront of chronostratigraphic research and initiatives to create an international geologic time scale for many years, and the charts in this book present the most up-to-date, international standard, as ratified by the International Commission on Stratigraphy and the International Union of Geological Sciences. This 2012 geologic time scale is an enhanced, improved and expanded version of the GTS2004, including chapters on planetary scales, the Cryogenian-Ediacaran periods/systems, a prehistory scale of human development, a survey of sequence stratigraphy, and an extensive compilation of stable-isotope chemostratigraphy. This book is an essential reference for all geoscientists, including researchers, students, and petroleum and mining professionals. The presentation is non-technical and illustrated with numerous colour charts, maps and photographs. The book also includes a detachable wall chart of the complete time scale for use as a handy reference in the office, laboratory or field. The most detailed international geologic time scale available that contextualizes information in one single reference for quick desktop access. Gives insights in the construction, strengths, and limitations of the geological time scale that greatly enhances its function and its utility. Aids understanding by combining with the mathematical and statistical methods to scaled composites of global succession of events. Meets the needs of a range of users at various points in the workflow (researchers extracting linear time from rock records, students recognizing the geologic stage by their content).


Geologic Time Scale 2020

Author by : Felix M. Gradstein
Languange : en
Publisher by : Unknown
Format Available : PDF, ePub, Mobi
Total Read : 53
Total Download : 883
File Size : 48,7 Mb
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Description : Geologic Time Scale 2020 contains contributions from leading scientists, with information presented in an easy-to-understand way including numerous color charts, maps, and photographs. Including recent information from such projects as GTSNext, Earth Time Europe, and Chronos, this updated edition explains in detail how and why the time scale is being updated and offers expanded coverage of paleontology and stratigraphy with an all-new atlas of index taxa at the end of each time period. The authors of Geologic Time Scale 2020 have been at the forefront of chronostratigraphic research and initiatives to create an international geologic time scale for many years, and the charts in this book present the most up-to-date, international standard as ratified by the International Commission on Stratigraphy and the International Union of Geological Sciences. As the framework for deciphering the history of our planet Earth, this book is essential for practicing Earth Scientists and academics.


A Concise Geologic Time Scale

Author by : J G Ogg
Languange : en
Publisher by : Elsevier
Format Available : PDF, ePub, Mobi
Total Read : 24
Total Download : 112
File Size : 45,9 Mb
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Description : A Concise Geologic Time Scale: 2016 presents a summary of Earth's history over the past 4.5 billion years, as well as a brief overview of contemporaneous events on the Moon, Mars, and Venus. The authors have been at the forefront of chronostratigraphic research and initiatives to create an international geologic time scale for many years, and the charts in this book present the most up-to-date international standard, as ratified by the International Commission on Stratigraphy and the International Union of Geological Sciences. This book is an essential reference for all geoscientists, including researchers, students, and petroleum and mining professionals. The presentation is non-technical and illustrated with numerous colour charts, maps and photographs. The book also includes a detachable laminated card of the complete time scale for use as a handy reference in the office, laboratory, or field. Presents a summary of Earth's history over the past 4.5 billion years Includes a brief overview of contemporaneous events on the Moon, Mars, and Venus Includes full-color figures including charts, stratigraphic profiles, and photographs to enhance understanding of each geologic period Correlates regional geologic stages to the standard definitions approved by the International Commission on Stratigraphy Offers an explanation of the methods used to create the time scale


Geologic Time Scale 2020

Author by : Felix M. Gradstein
Languange : en
Publisher by : Elsevier
Format Available : PDF, ePub, Mobi
Total Read : 29
Total Download : 576
File Size : 55,8 Mb
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Description : Geologic Time Scale 2020 (2 volume set) contains contributions from 80+ leading scientists who present syntheses in an easy-to-understand format that includes numerous color charts, maps and photographs. In addition to detailed overviews of chronostratigraphy, evolution, geochemistry, sequence stratigraphy and planetary geology, the GTS2020 volumes have separate chapters on each geologic period with compilations of the history of divisions, the current GSSPs (global boundary stratotypes), detailed bio-geochem-sequence correlation charts, and derivation of the age models. The authors are on the forefront of chronostratigraphic research and initiatives surrounding the creation of an international geologic time scale. The included charts display the most up-to-date, international standard as ratified by the International Commission on Stratigraphy and the International Union of Geological Sciences. As the framework for deciphering the history of our planet Earth, this book is essential for practicing Earth Scientists and academics. • Completely updated geologic time scale • Provides the most detailed integrated geologic time scale available that compiles and synthesize information in one reference • Gives insights on the construction, strengths and limitations of the geological time scale that greatly enhances its function and its utility


The Geologic Time Scale 2020

Author by : Felix M. Gradstein
Languange : en
Publisher by : Unknown
Format Available : PDF, ePub, Mobi
Total Read : 40
Total Download : 549
File Size : 51,8 Mb
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Description :


Strata And Time

Author by : D.G. Smith
Languange : en
Publisher by : Geological Society of London
Format Available : PDF, ePub, Mobi
Total Read : 80
Total Download : 205
File Size : 43,5 Mb
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Description : This Special Publication explores the relationship between the preserved strata of the rock record and the passage of time. It covers the controls on preservation of strata in the record, through the qualitative and statistical properties of statigraphic data, to the implications for analysis, interpretation, modelling and prediction.


Studyguide For The Geologic Time Scale 2012 2 Volume Set By Gradstein F M

Author by : Cram101 Textbook Reviews
Languange : en
Publisher by : Cram101
Format Available : PDF, ePub, Mobi
Total Read : 96
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File Size : 41,9 Mb
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Description : Never HIGHLIGHT a Book Again Includes all testable terms, concepts, persons, places, and events. Cram101 Just the FACTS101 studyguides gives all of the outlines, highlights, and quizzes for your textbook with optional online comprehensive practice tests. Only Cram101 is Textbook Specific. Accompanies: 9780872893795. This item is printed on demand.


Geomathematics Theoretical Foundations Applications And Future Developments

Author by : Frits Agterberg
Languange : en
Publisher by : Springer
Format Available : PDF, ePub, Mobi
Total Read : 24
Total Download : 277
File Size : 52,8 Mb
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Description : This book provides a wealth of geomathematical case history studies performed by the author during his career at the Ministry of Natural Resources Canada, Geological Survey of Canada (NRCan-GSC). Several of the techniques newly developed by the author and colleagues that are described in this book have become widely adopted, not only for further research by geomathematical colleagues, but by government organizations and industry worldwide. These include Weights-of-Evidence modelling, mineral resource estimation technology, trend surface analysis, automatic stratigraphic correlation and nonlinear geochemical exploration methods. The author has developed maximum likelihood methodology and spline-fitting techniques for the construction of the international numerical geologic timescale. He has introduced the application of new theory of fractals and multi fractals in the geostatistical evaluation of regional mineral resources and ore reserves and to study the spatial distribution of metals in rocks. The book also contains sections deemed important by the author but that have not been widely adopted because they require further research. These include the geometry of preferred orientations of contours and edge effects on maps, time series analysis of Quaternary retreating ice sheet related sedimentary data, estimation of first and last appearances of fossil taxa from frequency distributions of their observed first and last occurrences, tectonic reactivation along pre-existing schistosity planes in fold belts, use of the grouped jackknife method for bias reduction in geometrical extrapolations and new applications of the theory of permanent, volume-independent frequency distributions.


Paleobiology Of The Polycystine Radiolaria

Author by : David Lazarus
Languange : en
Publisher by : John Wiley & Sons
Format Available : PDF, ePub, Mobi
Total Read : 35
Total Download : 829
File Size : 47,6 Mb
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Description : Polycystine radiolaria are exclusively marine protists and are found in all ocean waters, from polar regions to the tropics, and at all water depths. There are approximately 600 distinct described living species and several thousand fossil species of polycystines. Radiolarians in general, and polycystines in particular, have recently been shown to be a major component of the living plankton and important to the oceanic carbon cycle. As fossils radiolarians are also fairly common, and often occur in sediments where other types of fossils are absent. This has made them very valuable for certain types of geologic research, particularly estimating the geologic age of the sediments containing them, and as guides to past oceanic water conditions. As our current understanding of the biology, and even taxonomy of the living fauna is still very incomplete, evolutionary studies based on living polycystines are still rare. However, the common occurrence of numerous specimens for many species, and in a wide variety of oceanic environments, provides an excellent opportunity to study the processes of biologic evolution in the fossil record. Paleobiology of the Polycystine Radiolaria is the first major book on radiolarians to appear in the western literature since 2001. Focusing on living and fossil siliceous shelled radiolarians, it is notable for its emphasis not upon morphologic or taxonomic detail but on concepts and applications. The book attempts to provide a balanced, critical review of what is known of the biology, ecology, and fossil record of the group, as well as their use in evolutionary, biostratigraphic and paleoceanographic research. Full chapters on the history of study, and molecular biology, are the first ever in book form. Written for an audience of advanced undergraduate to doctoral students, as well as for a broad range of professionals in the biological and Earth sciences, Paleobiology of the Polycystine Radiolaria summarizes current understanding of the marine planktonic protist group polycystine radiolaria, both in living and fossil form.


The Late Triassic World

Author by : Lawrence H. Tanner
Languange : en
Publisher by : Springer
Format Available : PDF, ePub, Mobi
Total Read : 37
Total Download : 403
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Description : This volume presents the latest science on all significant geological and paleontological aspects of the Earth during the Late Triassic Period. Rather than presenting a collection of narrowly focused research papers, the volume consists of a series of peer-reviewed chapters on specific aspects of the Late Triassic world (e.g., tectonics, magmatism, paleobotany, climate, etc.), all authored by experts in the subject of their respective chapters. Each chapter reviews and summarizes the latest findings in these fields and also includes a review of the pertinent literature. The author list is very broadly international and forms a veritable who’s who of expertise in these fields. The book is loosely organized to present the physical aspects of Earth during the Late Triassic at the outset, followed by the paleontological aspects. The latter section is further organized to present the record of the marine environment first before moving onto land, with fauna followed by flora. The volume closes with a review of the end-Triassic extinctions.


Earth System Evolution And Early Life

Author by : A.T. Brasier
Languange : en
Publisher by : Geological Society of London
Format Available : PDF, ePub, Mobi
Total Read : 40
Total Download : 791
File Size : 42,8 Mb
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Description : This volume in memory of Professor Martin Brasier, which has many of his unfinished works, summarizes recent progress in some of the hottest topics in palaeobiology including cellular preservation of early microbial life and early evolution of macroscopic animal life, encompassing the Ediacara biota. The papers focus on how to decipher evidence for early life, which requires exceptional preservation, employment of state-of-the-art techniques and also an understanding gleaned from Phanerozoic lagerstätte and modern analogues. The papers also apply Martin’s MOFAOTYOF principle (my oldest fossils are older than your oldest fossils), requiring an integrated approach to understanding fossils. The adoption of the null-hypothesis that all putative traces of life are abiotic until proven otherwise, and the consideration of putative fossils within their spatial context, characterized the work of Martin Brasier, as is well demonstrated by the papers in this volume.


The Stratigraphic Record Of Gubbio

Author by : Marco Menichetti
Languange : en
Publisher by : Geological Society of America
Format Available : PDF, ePub, Mobi
Total Read : 25
Total Download : 310
File Size : 44,7 Mb
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Description : Since the beginning of the last century, the lower Jurassic to mid-Miocene pelagic succession exposed along the valleys of the Umbria and Marche Apennines of Italy represented a fertile playground for generations of earth scientists. This GSA Special Paper provides a reappraisal of the geological and integrated stratigraphic research, which was carried out by scores of earth scientists in the gorges around the medieval city of Gubbio over the past fifty years. Following review chapters about pioneering sedimentologic, biostratigraphic, and magnetostratigraphic studies of the Gubbio sections, a series of papers presents new, original data addressing different stratigraphical, paleoenvironmental, and structural geological aspects of particular Cretaceous to Paleogene intervals, including the still much-debated K-Pg Boundary Event in the worldwide famous site of the Bottaccione Gorge, where the Alvarez theory of global mass extinction caused by a catastrophic extraterrestrial impact was born in 1980.


A Concise Geologic Time Scale

Author by : J G. Ogg
Languange : en
Publisher by : Elsevier
Format Available : PDF, ePub, Mobi
Total Read : 54
Total Download : 170
File Size : 49,7 Mb
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Description : "A Concise Geologic Time Scale: 2016" presents a summary of Earth's history over the past 4.5 billion years, as well as a brief overview of contemporaneous events on the Moon, Mars, and Venus. The authors have been at the forefront of chronostratigraphic research and initiatives to create an international geologic time scale for many years, and the charts in this book present the most up-to-date international standard, as ratified by the International Commission on Stratigraphy and the International Union of Geological Sciences. This book is an essential reference for all geoscientists, including researchers, students, and petroleum and mining professionals. The presentation is non-technical and illustrated with numerous colour charts, maps and photographs. The book also includes a detachable laminated card of the complete time scale for use as a handy reference in the office, laboratory, or field. Presents a summary of Earth's history over the past 4.5 billion yearsIncludes a brief overview of contemporaneous events on the Moon, Mars, and VenusIncludes full-color figures including charts, stratigraphic profiles, and photographs to enhance understanding of each geologic periodCorrelates regional geologic stages to the standard definitions approved by the International Commission on StratigraphyOffers an explanation of the methods used to create the time scale


Unfolding The Geology Of The West

Author by : Stephen M. Keller
Languange : en
Publisher by : Geological Society of America
Format Available : PDF, ePub, Mobi
Total Read : 68
Total Download : 208
File Size : 48,7 Mb
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Description : "Sixteen geologic field guides explore areas in Colorado, New Mexico, Utah, and Montana"--


Resolving The Timing Of Events Around The Cretaceous Paleogene Boundary

Author by : Courtney Jean Sprain
Languange : en
Publisher by : Unknown
Format Available : PDF, ePub, Mobi
Total Read : 60
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Description : Despite decades of study, the exact cause of the Cretaceous-Paleogene boundary (KPB) mass extinction remains contentious. Hypothesized scenarios center around two main environmental perturbations: voluminous (>10^6 km3) volcanic eruptions from the Deccan Traps in modern-day India, and the large impact recorded by the Chicxulub crater. The impact hypothesis has gained broad support, bolstered by the discoveries of iridium anomalies, shocked quartz, and spherules at the KPB worldwide, which are contemporaneous with the Chicxulub impact structure. However, evidence for protracted extinctions, particularly in non-marine settings, and paleoenvironmental change associated with climatic swings before the KPB, challenge the notion that the impact was the sole cause of the KPB mass extinction. Despite forty years of study, the relative importance of each of these events is unclear, and one key inhibitor is insufficient resolution of existing geochronology. In this dissertation, I present work developing a high-precision global chronologic framework for the KPB that outlines the temporal sequence of biotic changes (both within the terrestrial and marine realms), climatic changes, and proposed perturbations (i.e. impact, volcanic eruptions) using 40Ar/39Ar geochronology and paleomagnetism. This work is focused on two major areas of study: 1) refining the timing and tempo of terrestrial ecosystem change around the KPB, and 2) calibrating the geomagnetic polarity timescale, and particularly the timing and duration of magnetic polarity chron C29r (the KPB falls about halfway into C29r). First I develop a high-precision chronostratigraphic framework for fluvial sediments within the Hell Creek region, in NE Montana, which is one of the best-studied terrestrial KPB sections worldwide. For this work I dated 15 tephra deposits with ± 30 ka precision using 40Ar/39Ar geochronology, ranging in time from ~300 ka before the KPB to 1 Ma after. By tying these results to paleontological records, this work is able to constrain the timing of terrestrial faunal decline and recovery in addition to calibrating late Cretaceous and early Paleocene North American Land Mammal Ages biostratigraphy. To aid in global correlation, I next sought to calibrate the timing and duration of C29r. However, based on discrepancies noticed between a calculated duration for C29r, from new dates collected as part of this dissertation and previously published magnetostratigraphy for the Hell Creek region, and the duration provided within the Geologic Time Scale 2012, it became clear that reliability of sediments from the Hell Creek as paleomagnetic recorders was suspect. To test this claim, a complete characterization of the rock magnetic properties of sediments from the Hell Creek region was undertaken. To aid characterization, a new test to determine the presence of intermediate composition titanohematite (Fe2-yTiyO3; 0.5 ≤ y ≤ 0.7) was developed. Results from rock magnetic characterization show that sediments from the Hell Creek should be reliable paleomagnetic recorders, so long as care is taken to remove goethite (a secondary mineral that previous magnetostratigraphic studies in the Hell Creek did not remove), and to avoid samples that have been heated above ~200oC. With the knowledge that sediments from the Hell Creek region are reliable magnetic recorders, I collected 14 new magnetostratigraphic sections, and 18 new high-precision 40Ar/39Ar dates which together provide constraints on the timing and duration of chron C29r, at unprecedented precision. This work enables correlation of our record in the Hell Creek to other KPB records around the globe, in addition to providing a test of the Paleocene astrochronologic timescale.


Contributions In Science

Author by : Anonim
Languange : en
Publisher by : Unknown
Format Available : PDF, ePub, Mobi
Total Read : 46
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Description :


Ku Chi Chui Tung Wu Hs Eh Pao

Author by : Anonim
Languange : en
Publisher by : Unknown
Format Available : PDF, ePub, Mobi
Total Read : 66
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File Size : 48,8 Mb
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Description :


Geological Quarterly

Author by : Anonim
Languange : en
Publisher by : Unknown
Format Available : PDF, ePub, Mobi
Total Read : 64
Total Download : 954
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Description :


Report

Author by : National Research Council (U.S.) Committee on the Measurement of Geologic Time
Languange : en
Publisher by : Unknown
Format Available : PDF, ePub, Mobi
Total Read : 76
Total Download : 378
File Size : 53,5 Mb
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Description :


Practical Hydrogeology Principles And Field Applications Third Edition

Author by : Willis D. Weight
Languange : en
Publisher by : McGraw Hill Professional
Format Available : PDF, ePub, Mobi
Total Read : 24
Total Download : 242
File Size : 52,6 Mb
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Description : Master the latest advances in hydrogeology using this fully updated resource This thoroughly revised guide clearly explains cutting-edge hydrogeology techniques that can be applied in the field. Featuring contributions from leading experts, Practical Hydrogeology: Principles and Field Applications, Third Edition, shows how to plan and conduct site investigations, avoid pitfalls in the field, interpret a wide array of data types gathered, and prepare water-quality reports. You will get complete coverage of key procedures, including aquifer testing, groundwater sampling, water-quality assessment, aquifer characterization, and tracer tests. This third edition has been reorganized and expanded with up-to-date information, a new chapter, review questions, and real-world examples. Coverage includes:•Field hydrogeology•The geology of hydrogeology•Aquifer properties•Groundwater flow•Pumping tests•Slug testing•Aquifer hydraulics•Water chemistry sampling•Groundwater/surface-water interaction•Vadose-zone analysis•Karst hydrogeology and tracer tests•Drilling and well completion


The First 40ar 39ar Ages And Tephrochronologic Framework For The Jurassic Entrada Sandstone In Central Utah

Author by : Toby S. Dossett
Languange : en
Publisher by : Unknown
Format Available : PDF, ePub, Mobi
Total Read : 44
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Description : The first 40Ar/39Ar ages of the Middle Jurassic Entrada Sandstone were derived from tephra beds found in central Utah. Eight air fall ash beds in the Entrada Sandstone, with 40Ar/39Ar biotite ages ranging from 168.1 ± 0.2 to 160.8 ± 0.2 Ma, help to establish the age of Entrada deposition. They were also used to create the first chronostratigraphic divisions within the mudstone-dominated Entrada Sandstone. Statistical cluster analysis of chemical data from electron microprobe analyses of phenocrysts were used as a second line of evidence to test absolute age and stratigraphic correlations. The first direct correlations of two distinct air fall ash beds within Jurassic rocks were correlated using three criteria: (1) stratigraphic position, (2) absolute ages, and (3) mineral chemistry. These tephra beds were identified and correlated across significant lateral distances (~40 km) of the San Rafael Swell in central Utah, and one can be correlated farther southwest to Cannonville, Utah (~160 km) using absolute age relationships. This latter tephra bed allows for stratigraphic correlation across significant facies and thickness changes thereby establishing a regional framework that future studies can use to make more accurate and precise litho- and sequence stratigraphic correlations. Absolute ages from a tephra bed ~20 m below the J-3 unconformity provide a lower age boundary for formation of the J-3 surface. Mega- and microfossil assemblages in the overlying Curtis Formation together with the radiometric ages reported in this study indicate that the age of the Callovian-Oxfordian boundary in the 2004 geologic time scale (161.2 ± 4.0 Ma) is more correct than the current boundary age (163.5 ± 1.1 Ma) in the 2012 geologic time scale.