Geologic Time

2021 ◽  
pp. 69-81
Author(s):  
Elisabeth Ervin-Blankenheim
Keyword(s):  
Time Scale ◽  
Age Dating ◽  
Marie Curie ◽  
Ernest Rutherford ◽  
Relative Age ◽  
Geologic Time ◽  
The Earth ◽  
Geologic Time Scale ◽  
Geologic Maps ◽  
History Of

Geologists first unraveled the geologic time scale by relative age-dating, discussed in the last chapter. Once geologists sorted out the order of rock units, subsequent advances in methodologies, detailed in this chapter, by chronometric and numerical means based on radioisotopes, other atomic measures, and quantitative techniques, were employed to measure time. Many minerals and rocks have “clocks” within them that can be used to pin down the actual age of the particular geologic sample or the age of boundaries between formal units of the geologic time scale. This chapter explains how geologists decipher those clocks and determine the ages of rocks by numerical age-dating. The history of radioisotopes is tracked, starting with Ernest Rutherford and Pierre and Marie Curie. The modern geologic time scale is depicted and expanded upon, along with why it is essential for geologic maps and how the time scale can help with people-sized problems and challenges faced on the Earth.

The times they are a-changin': Australian biozones, petroleum basins, and the international geologic time scale (GTS) 2012

2014 ◽  
Vol 54 (2) ◽  
pp. 473
Author(s):  
Tegan Smith ◽  
John Laurie ◽  
Lisa Hall ◽  
Robert Nicoll ◽  
Andrew Kelman ◽  
...  
Keyword(s):  
Time Scale ◽  
Age Dating ◽  
Burial History ◽  
Geologic Time ◽  
Petroleum Systems ◽  
Geologic Time Scale ◽  
History Of ◽  
And Migration ◽  
The Times ◽  
Hydrocarbon Expulsion

The international Geologic Time Scale (GTS) continually evolves due to refinements in age dating and the addition of more defined stages. The GTS 2012 has replaced GTS 2004 as the global standard timescale, resulting in changes to the age and duration of most chronological stages. These revisions have implications for interpreted ages and durations of sedimentary rocks in Australian basins, with ramifications for petroleum systems modelling. Accurate stratigraphic ages are required to reliably model the burial history of a basin, hence kerogen maturation and hydrocarbon expulsion and migration. When the resolution of the time scale is increased, models that utilise updated ages will better reflect the true basin history. The international GTS is largely built around northern hemisphere datasets. At APPEA 2009, Laurie et al. announced a program to tie Australian biozones to GTS 2004. Now, with the implementation of GTS 2012, these ties are being updated and refined, requiring a comprehensive review of the correlations between Australian and International biozonation schemes. The use of Geoscience Australia’s Timescales Database and a customised ‘Australian Datapack’ for the visualisation software package TimeScale Creator has greatly facilitated the transition from GTS 2004 to GTS 2012, as anticipated in the design of the program in 2009. Geoscience Australia’s basin biozonation and stratigraphy charts (e.g. Northern Carnarvon and Browse basins) are being reproduced to reflect the GTS 2012 and modified stratigraphic ages. Additionally, new charts are being added to the series, including a set of onshore basin charts, such as the Georgina and Canning basins.

Sequencing Time

1996 ◽  
Vol 2 ◽  
pp. 127-136
Author(s):  
Judy Scotchmoor
Keyword(s):  
Time Scale ◽  
Geologic Time ◽  
The Earth ◽  
Geologic Time Scale ◽  
History Of

Telling the history of the earth requires placing events in sequence so that reference can be given to the relative and/or numerical time at which each event occurred. This helps to make sense out of the enormous expanse of time that has elapsed since the origin of the earth. This activity will help students to understand the methods used by geologists in creating the Geologic Time Scale.

The History of the Earth in the hallways

2020 ◽  
Author(s):  
Paloma Ramírez Vongrejova ◽  
María José Massé Rodríguez
Keyword(s):  
School Students ◽  
Learning Groups ◽  
Geologic Time ◽  
The Earth ◽  
Experience Teaching ◽  
Widespread Agreement ◽  
Geologic Time Scale ◽  
History Of ◽  
The Subject ◽  
Research Period

<p><span>There is widespread agreement among my fellow colleagues who teach Geology that the History of our planet is a tough topic for teenagers. Unfortunately, not only is the subject considered boring but also useless by the majority of our school students.</span></p><p><span>Our experience teaching these contents in a traditional way has shown us that pupils vaguely remember anything. In order to give a different approach to this issue and, therefore, to promote meaningful learning, we have designed a project where students must be fully engaged.</span></p><p><span>First, the class was organized in cooperative learning groups, so they had to collaborate to complete the task. Then, they started the research period using laptop computers available in the school. Students now dealt with specific vocabulary such as the geologic time scale terms but also a variety of events that occurred from the very first moments, from the formation of the Earth itself to the development of the big reptiles that have always fascinated children and adults, especially their dramatic extinction.</span></p><p> <span><span>Once the topic was developed in detail, they were required to make a poster on scale with the information collected. It was undeniable that pictures or photographs must cover most of the poster as long as short sentences describing both biological and geological phenomena. What we were also concerned about their learning was to improve their creativity. Because of this, they were encouraged to make their own drawings.</span></span></p><p><span>Students really liked the activity, built stronger relationships between them and the final products were so amazing that were exhibited in the walls of the hallways outside their classroom.</span></p><p><span>All these events have been recorded in the rocks so geologists could unfold part of the mysteries of our History. Our teenagers discovered them an represented them for us to enjoy.</span></p>

scholarly journals On the Anthropocene formalization and the proposal by the Anthropocene Working Group

2020 ◽  
Vol 18 ◽  
pp. 1-10
Author(s):  
C. Soriano
Keyword(s):  
Empirical Evidence ◽  
Empirical Data ◽  
Time Scale ◽  
Working Group ◽  
The Other ◽  
Comprehensive Understanding ◽  
Geologic Time ◽  
Earth History ◽  
The Earth ◽  
Geologic Time Scale

In the coming years the Anthropocene will be likely submitted to formalization by the Anthropocene Working Group as a chronostratigraphic unit of the Geologic Time Scale. This has generated an increasing debate among detractors and defenders of its formalization in general, and of the proposal by the Anthropocene Working Group in particular. Here, the main issues regarding the Geologic Time Scale and the rules to formalize units, the empirical data supporting the Anthropocene formalization and the critiques to formalize it are critically reviewed. The procedure to formalize the Anthropocene is not dissimilar from those of the other units of the Geologic Time Scale and has been essentially based on stratigraphic and geologic criteria. Following the recommendation of the Anthropocene Working Group and based on the empirical evidence on the Anthropocene as it is expressed in strata and, more important, on the immanent and structural link between the Anthropocene and the reproduction of capital, it is proposed to define Capitalian as a Stage of the Anthropocene Epoch. In this way, a truly comprehensive understanding of the Earth history is obtained, which comprises the ultimate causes of the ongoing planetary transformation and its stratatigraphic expression.

Introduction to Radiometric Dating

2006 ◽  
Vol 12 ◽  
pp. 1-23 ◽  
Author(s):  
Brent V. Miller
Keyword(s):  
Time Scale ◽  
Radiometric Dating ◽  
Current Status ◽  
Origin And Evolution ◽  
Geologic Time ◽  
The Earth ◽  
Dating Methods ◽  
Rock Record ◽  
Geologic Time Scale ◽  
Radiometric Dates

Radiometric dating of rocks and minerals to constrain the age of the Earth, timing of geological events and paleobiological histories has its roots in the works of nuclear physicists of the early Nineteenth Century during the period of discovery of radioactivity and investigations into the nature of the atom. The intervening years since have seen great progress in using the long-lived radioactive elements to constrain the origin and evolution of the Earth and to place the rock and fossil record into a consistent, numerically quantifiable temporal framework.U-Th-Pb and40Ar/39Ar dating methods have emerged as the primary tools for calibrating most of Earth history. It is important for all geoscientists to appreciate the physical basis underlying these methods and to have the ability to evaluate dates by means of currently accepted practices of data presentation. This introduction, along with the accompanying chapters, is intended to help the consumers of radiometric dates to understand better the uses and limitations of radiometric dating methods in an effort to tailor methods and techniques to address specific geochronologic needs, including calibration of the geologic time scale.The ultimate goal of a fully calibrated rock record remains an on-going endeavor. The 2004 ICS geologic time scale is the latest compilation of those efforts. The numerical age calibration is constrained by only 213 radiometric dates, the vast majority of which are U-Pb and40Ar/39Ar dates. Radiometric age control is not evenly distributed through geologic time. There are virtually no radiometric dates in the late Cenozoic where magnetostratigraphy and cyclostratigraphic methods are more precise and applicable. Radiometric dating efforts are concentrated on biostratigraphically important segments of the rock record such as the Permian-Triassic and Cretaceous-Paleocene boundary events, and this is reflected in high-precision calibration of these boundaries. Large segments of geologic time, however, are constrained by either a few radiometric dates per chronostratigraphic unit (most of the Paleozoic) or none at all (Upper Triassic). The current status of radiometric age control on the rock record largely reflects real, underlying scientific issues in biostratigraphy and geochronology, and thus can help point the way to fruitful lines of collaboration between paleontologists, stratigraphers, and geochronologists.

scholarly journals Book Review: Earth’s Landscape: An Encyclopedia of the World’s Geographic Features

2015 ◽  
Vol 55 (2) ◽  
pp. 178
Author(s):  
Lisa Presley
Keyword(s):  
Time Scale ◽  
Background Information ◽  
Surface Features ◽  
Geologic Time ◽  
The Earth ◽  
Geologic Time Scale ◽  
Major Surface

Authors Joyce Quinn and Susan Woodward combine their decades of research, teaching, and knowledge in Earth’s Landscape: An Encyclopedia of the World’s Geographic Features. The entries in this two volume set focus on 460 of the natural geographic features of the earth. The introduction provides a wealth of useful background information, including a table of the geologic time scale, a table of major climate types and descriptions of the earth’s major surface features.

The Geological Time Scale

2006 ◽  
Vol 12 ◽  
pp. 107-123 ◽  
Author(s):  
Felix M. Gradstein
Keyword(s):  
Time Scale ◽  
Best Practice ◽  
Age Dating ◽  
Geological Time ◽  
Geological Time Scale ◽  
Geologic Time ◽  
Global Correlation ◽  
Geologic Time Scale ◽  
Orbital Tuning ◽  
Stage Boundaries

This lecture reviews Geologic Time Scale 2004 (Gradstein, Ogg et al., 2004; Cambridge University Press), constructed and detailed by 40 geoscience specialists, and indicates how it will be further refined. Since Geologic Time Scale 1989 by Harland et al., many developments have taken place: (1) Stratigraphic standardization through the work of the International Commission on Stratigraphy (ICS) has greatly refined the international chronostratigraphic scale. In some cases, traditional European-based stages have been replaced with new subdivisions that allow global correlation. (2) New or enhanced methods of extracting high-precision age assignments with realistic uncertainties from the rock record. These have led to improved age assignments of key geologic stage boundaries and other global correlation horizons. (3) Orbital tuning has greatly refined the Neogene, and improved parts of Paleogene and Mesozoic. (4) Statistical techniques of compiling integrated global stratigraphic scales within geologic periods.Anticipated advances to the Geologic Time Scale during the next 8 years include: a geologically realistic Precambrian scale, formal definition of all Phanerozoic stage boundaries, orbital tuning of polarity chrons and biostratigraphic events for entire Cenozoic and Cretaceous, a detailed database of high-resolution radiometric ages that includes “best practice” procedures, full error analysis, monitor ages and conversions, resolving age dating controversies (e.g., zircon statistics and possible reworking) across Devonian/Carboniferous, Permian/Triassic, and Anisian/Ladinian boundaries, improved and standardized dating of several ‘neglected’ intervals (e.g., Upper Jurassic – Lower Cretaceous, and Carboniferous through Triassic, and detailed integrated stratigraphy for Upper Paleozoic through Lower Mesozoic.The geochronological science community and ICS are focusing on these issues. A modified version of the time scale to accompany the standardization (boundary definitions and stratotypes) of all stages is planned for 2008 (to be presented at the 33th International Geologic Congress in Oslo), with a totally revised version of GTS available in 2012.

A Geologic Time Scale 1989. W. B. Harland

1991 ◽  
Vol 99 (5) ◽  
pp. 786-786
Author(s):  
John J. Flynn
Keyword(s):  
Time Scale ◽  
Geologic Time ◽  
Geologic Time Scale

LEONARDO DA VINCI’S AND NICOLAUS STENO’S GEOLOGY

2021 ◽  
Vol 40 (2) ◽  
pp. 293-331
Author(s):  
GIAN BATTISTA VAI
Keyword(s):  
Comparative Evaluation ◽  
Geological History ◽  
Basic Principles ◽  
Founding Fathers ◽  
Angular Unconformity ◽  
Geologic Time ◽  
The Earth ◽  
Relative Chronology ◽  
History Of ◽  
Do So

Anniversaries for the two founding fathers of geology occurring in the same year prompted a comparative evaluation of how the two contributed to establishing the basic principles of the discipline. To do so, passages from their publications, codices and manuscripts have been quoted directly. The Stenonian principles (‘original horizontality’, ‘original continuity’, and ‘superposition of individual strata’) are present in Leonardo’s notebooks amazingly formulated, using similar wording when studying the same area more than 150 years earlier. Also, Stenonian priority in naming and explaining geological concepts and processes (e.g., faulting, folding, angular unconformity, relative chronology) are mirrored in Leonardo’s writings and pictorial works. While Steno enjoys priority in stepwise restoration of the geological history of a given region, Leonardo was the first to construct a 3D geological profile representation and geomorphologic maps. Lastly, the paper focuses on diverging stances of the two savants about the Noachian Deluge and the age of the Earth. Already 500 years ago, Leonardo had solved the question of marine fossil remains of organic origin found in the mountains implying the possibility of deep geologic time in a statement of ‘eternalism’. 350 years ago, Steno solved the same question in a different way in which he retained a basic role for the Deluge and assumed a short age for the Earth by focusing mainly on short-lived sedimentary and geomorphologic processes.

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