Geologic time scale: Wikis

  
  
  
  

Did you know ...


More interesting facts on Geologic time scale

Include this on your site/blog:










Encyclopedia

From Wikipedia, the free encyclopedia

.
This clock representation shows some of the major units of geological time and definitive events of Earth history.
^ The time scale used to describe events in the history of Earth.
  • Evolution: Glossary 3 February 2010 15:51 UTC www.pbs.org [Source type: Academic]

^ The chronological sequence of units of Earth time.
  • Department of Geological & Atmospheric Sciences 3 February 2010 15:51 UTC www.ge-at.iastate.edu [Source type: FILTERED WITH BAYES]
  • Department of Geological & Atmospheric Sciences 3 February 2010 15:51 UTC www.ge-at.iastate.edu [Source type: FILTERED WITH BAYES]

^ It encompasses the great majority of geologic time.
  • GG101 Geologic Time 3 February 2010 15:51 UTC honolulu.hawaii.edu [Source type: FILTERED WITH BAYES]

.The Hadean eon represents the time before fossil record of life on Earth; its upper boundary is now regarded as 4.0 Ga [1].^ Ma: The activity of the algae had by now increased the earth's oxygen content to about 20% thus allowing more complex life forms to evolve.
  • Geological Time Scale 3 February 2010 15:51 UTC www.namibia-1on1.com [Source type: FILTERED WITH BAYES]

^ The only evidence (apart from divine revelation, which the evolutionist refuses to accept) concerning pre-historic life on the earth is that which can be deduced from the fossil remains of creatures now buried in the rocks of the earths crust.
  • "The Geologic History" by Henry M. Morris 3 February 2010 15:51 UTC www.the-highway.com [Source type: Original source]

^ So vast is the span of time recorded in the history of the Earth that it's generally distinguished from the more modest kinds of time by being called "geologic time."
  • GG101 Geologic Time 3 February 2010 15:51 UTC honolulu.hawaii.edu [Source type: FILTERED WITH BAYES]

.Other subdivisions reflect the evolution of life; the Archean and Proterozoic are both eons, the Palaeozoic, Mesozoic and Cenozoic are eras of the Phanerozoic eon.^ The current eon, the Phanerozoic, has had three eras, the Paleozoic, Mesozoic, and Cenozoic, which is the current era.

^ Most geologists recognize three eons: the Archean, the Proterozoic, and the Phanerozoic.

^ CENOZOIC ERA ("recent life") zero to 65 Mya.: [ see map and Geological data .
  • Geological Time Scale for the origins and evolution of life. 3 February 2010 15:51 UTC www.ecotao.com [Source type: FILTERED WITH BAYES]

The two million year Quaternary period, the time of recognizable humans, is too small to be visible at this scale.
.The geologic time scale provides a system of chronologic measurement relating stratigraphy to time that is used by geologists, paleontologists and other earth scientists to describe the timing and relationships between events that have occurred during the history of the Earth.^ The time scale used to describe events in the history of Earth.
  • Evolution: Glossary 3 February 2010 15:51 UTC www.pbs.org [Source type: Academic]

^ Given the background above, the information used for a geologic time scale can be related like this: .
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

^ A Geologic Time Scale: 1982 edition.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

.The table of geologic time spans presented here agrees with the dates and nomenclature proposed by the International Commission on Stratigraphy, and uses the standard color codes of the United States Geological Survey.^ State geological survey office links .
  • Fogler Library Resources by Subject: Geology 3 February 2010 15:51 UTC www.library.umaine.edu [Source type: Academic]

^ Color landform atlas of the United States .
  • Fogler Library Resources by Subject: Geology 3 February 2010 15:51 UTC www.library.umaine.edu [Source type: Academic]

^ This is a Geologically short time span.
  • Galactic Geologic Interval Theory - Astronomy.com Forums 17 January 2010 12:35 UTC cs.astronomy.com [Source type: FILTERED WITH BAYES]

.Evidence from radiometric dating indicates that the Earth is about 4.570 billion years old.^ What were these organisms that evolved on earth about 4 billion years ago?
  • Geological Background 3 February 2010 15:51 UTC uts.cc.utexas.edu [Source type: FILTERED WITH BAYES]

^ Evidence from radiometric dating indicates that the Earth is about 4,570 million years old (expressed with m.y.a., i.e.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ Based on radioactive dating techniques scientists calculate the Earth is about 4.5 billion years old.
  • GEOLOGY OF FLORIDA 3 February 2010 15:51 UTC www.clas.ufl.edu [Source type: FILTERED WITH BAYES]

.The geological or deep time of Earth's past has been organized into various units according to events which took place in each period.^ The order of events according to time.
  • Evolution: Glossary 3 February 2010 15:51 UTC www.pbs.org [Source type: Academic]

^ The geological or deep time of Earth's past has been organized into various units according to events which took place in each period.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ The chronological sequence of units of Earth time.
  • Department of Geological & Atmospheric Sciences 3 February 2010 15:51 UTC www.ge-at.iastate.edu [Source type: FILTERED WITH BAYES]
  • Department of Geological & Atmospheric Sciences 3 February 2010 15:51 UTC www.ge-at.iastate.edu [Source type: FILTERED WITH BAYES]

.Different spans of time on the time scale are usually delimited by major geological or paleontological events, such as mass extinctions.^ The geological time scale is far from dogma.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

^ Different spans of time on the time scale are usually delimited by major geological or paleontological events, such as mass extinctions .
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ This is a Geologically short time span.
  • Galactic Geologic Interval Theory - Astronomy.com Forums 17 January 2010 12:35 UTC cs.astronomy.com [Source type: FILTERED WITH BAYES]

.For example, the boundary between the Cretaceous period and the Paleogene period is defined by the Cretaceous–Tertiary extinction event, which marked the demise of the dinosaurs and of many marine species.^ In 1977, the Global Commission on Stratigraphy (now the International Commission on Stratigraphy ) started an effort to define global references ( Global Boundary Stratotype Sections and Points ) for geologic periods and faunal stages.

^ For example, the boundary between the Cretaceous and Tertiary periods is recognized on the basis of the extinction of a large number of organisms globally (including ammonites, dinosaurs, and others), the first appearance of new types of organisms, the presence of geochemical anomalies (notably iridium), and unusual types of minerals related to meteorite impact processes (impact spherules and shocked quartz).
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

^ DINOSAURS became extinct around 65 MYA during a mass extinction known as the CRETACEOUS-TERTIARY Mass Extinction Event or K/T BOUNDARY EVENT. It is widely believed that the event resulted from the collision of an asteroid with Earth, at a point on the northwest coastline of the Yucatan Peninsula in Mexico called the Chicxulub crater (named for a local village).
  • Serpo.org - The Zeta Reticuli Exchange Program (Release 30) 3 February 2010 15:51 UTC www.serpo.org [Source type: FILTERED WITH BAYES]

.Older periods which predate the reliable fossil record are defined by absolute age.^ Older periods which predate the reliable fossil record are defined by absolute age.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ Periodic surges at its lobes and edges produced local burial of slightly older tills, all of essentially the same age.
  • OPPOSITION TO CREATIONISM 7 OF 9 3 February 2010 15:51 UTC www.csun.edu [Source type: Academic]

^ By itself, relative dating cannot assign any absolute age to rocks or fossils.
  • Evolution: Glossary 3 February 2010 15:51 UTC www.pbs.org [Source type: Academic]

.Each era on the scale is separated from the next by a major event or change.^ Different spans of time on the time scale are usually delimited by major geological or paleontological events, such as mass extinctions .
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ One version (Froede, 1995) has a rudimentary scale with major eras being Creation Week, Antediluvian Ages, Flood Event, Ice Age, and Present.
  • OPPOSITION TO CREATIONISM 7 OF 9 3 February 2010 15:51 UTC www.csun.edu [Source type: Academic]

^ The following table summarizes the major events and characteristics of the periods of time making up the geologic time scale.

Contents

Graphical timelines

.The second and third timelines are each subsections of their preceding timeline as indicated by asterisks.^ The second and third timelines are each subsections of their preceding timeline as indicated by asterisks.

Millions of Years
The Holocene (the latest epoch) is too short to be shown clearly on this timeline.

Terminology

e  h
Units in geochronology and stratigraphy[2]
Segments of rock (strata) in chronostratigraphy Periods of time in geochronology Notes
Eonothem
Eon
4 total, half a billion years or more
Erathem
Era
12 total, several hundred million years
System
Period
Series
Epoch
tens of millions of years
Stage
Age
millions of years
Chronozone
Chron
smaller than an age/stage, not used by the ICS timescale
.The largest defined unit of time is the supereon, composed of eons.^ Era A unit of geological time, next in order of magnitude below an Eon.
  • Glossary of Common Geoscience Terms - Geoscience Australia 17 January 2010 12:35 UTC www-a.ga.gov.au [Source type: FILTERED WITH BAYES]

^ The end of the Proterozoic eon, once again, is not sharply defined in the stratigraphic record, such that there is considerable dispute as to the time periods involved.

^ For this reason, when discussing Precambrian time, it is usually necessary to consider only the three eons that composed it.

.Eons are divided into eras, which are in turn divided into periods, epochs and ages.^ Eons are divided into Eras, which are in turn divided into Periods, Epochs and Stages.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ The orders in turn are divided into families; the order Carnivora includes the families Felidae (the cats), Canidae (the dogs), and Ursidae (the bears), among others.
  • Evolution: Glossary 3 February 2010 15:51 UTC www.pbs.org [Source type: Academic]

^ Example: The Tertiary period was the earliest period in the Cenozoic era and included, among others, the Eocene epoch.
  • Department of Geological & Atmospheric Sciences 3 February 2010 15:51 UTC www.ge-at.iastate.edu [Source type: FILTERED WITH BAYES]
  • Department of Geological & Atmospheric Sciences 3 February 2010 15:51 UTC www.ge-at.iastate.edu [Source type: FILTERED WITH BAYES]

.The terms eonothem, erathem, system, series, and stage are used to refer to the layers of rock that correspond to these periods of geologic time.^ Ages of rocks are linked to distribution maps for each geologic time period.
  • California Maps - HSU Library 17 January 2010 12:35 UTC library.humboldt.edu [Source type: Academic]

^ Period A geological time subdivision of an Era , during which the rocks of the corresponding system were formed.
  • Glossary of Common Geoscience Terms - Geoscience Australia 17 January 2010 12:35 UTC www-a.ga.gov.au [Source type: FILTERED WITH BAYES]

^ The time corresponding to most of these intervals of rock became known as geologic "ages" and "periods", respectively.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

.Geologists qualify these units as Upper, Middle, and Lower.^ Upper , Middle , and Lower are terms applied to the rocks themselves, as in "Upper Jurassic sandstone," while Late , Middle , and Early are applied to time, as in "Early Jurassic deposition" or "fossils of Early Jurassic age."
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ These should be selected from the following list (to include at least 11 units of upper division Geology courses): .
  • Geological Sciences 3 February 2010 15:51 UTC tracs.csun.edu [Source type: Academic]

^ Geologists tend to talk in terms of Upper/Late, Lower/Early and Middle parts of periods and other units , such as "Upper Jurassic ", and "Middle Cambrian ".
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

Examples are "Upper Jurassic" and "Middle Cambrian". The adjectives are capitalized when the subdivision is formally recognized, and lower case when not; thus "early Miocene" but "Early Jurassic." The names of subdivisions can vary when discussing either position in the geologic record or corresponding time period, by use of either upper/lower (for series) or late/early (for epochs). .For example, the Lower Jurassic Series in geochronology corresponds to the Early Jurassic Epoch in chronostratigraphy.^ Epoch: One subdivision of a geologic period, often chosen to correspond to a stratigraphic series.
  • Glossary of Geological Terms 17 January 2010 12:35 UTC www.geotech.org [Source type: FILTERED WITH BAYES]

[3]
.Geologic units from the same time but different parts of the world often look different and contain different fossils, so the same period was historically given different names in different locales.^ TIMENAME Name of the geologic time unit (Source: Geological Society of America) .
  • Digital Geologic Map Database of the Nevada Test Site Area, Nevada 17 January 2010 12:35 UTC geo-nsdi.er.usgs.gov [Source type: Academic]

^ Because geologic units occurring at the same time but from different parts of the world can often look different and contain different fossils, there are many examples where the same period was historically given different names in different locales.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ A name for a time unit .
  • Digital Geologic Map Database of the Nevada Test Site Area, Nevada 17 January 2010 12:35 UTC geo-nsdi.er.usgs.gov [Source type: Academic]

.For example, in North America the Lower Cambrian is called the Waucoban series that is then subdivided into zones based on succession of trilobites.^ For example, in North America the Lower Cambrian is referred to as the Waucoban series that is then subdivided into zones based on trilobites .
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ Possible location of the Mesozoic suture zone, the boundary between ancient Africa and ancient North America, formed by their collision (Nelson et al ., 1985).
  • GEOLOGY OF FLORIDA 3 February 2010 15:51 UTC www.clas.ufl.edu [Source type: FILTERED WITH BAYES]

^ The Arctic Platform merges northward into a Cambrian-Lower Devonian southern shelf assemblage of 5 km of carbonate, shale and evaporite.

.In East Asia and Siberia, the same unit is split into Tommotian, Atdabanian, and Botomian stages.^ Another by Walker (1994) splits geologic time into eras and stages, based largely on numbers of days during creation week and the flood event.
  • OPPOSITION TO CREATIONISM 7 OF 9 3 February 2010 15:51 UTC www.csun.edu [Source type: Academic]

.A key aspect of the work of the International Commission on Stratigraphy is to reconcile this conflicting terminology and define universal horizons that can be used around the world.^ It is a key aspect of the work of the International Commission on Stratigraphy to reconcile this conflicting terminology and define universal horizons that can be used around the world.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ Note: The time scale used is as determined by the International Committee on Stratigraphy (ICS) .
  • Geological Time Scale Namibia 17 January 2010 12:35 UTC www.namibia-1on1.com [Source type: FILTERED WITH BAYES]

^ However, the International Commission on Stratigraphy has recently decided to stop endorsing the terms Quaternary and Tertiary as part of the formal nomenclature.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

[4]

History of the time scale and names

Animation showing Earth's palaeogeographic reconstruction beginning from early Cambrian period.
Diagram of geological time scale, where the past is toward the bottom of the spiral
.In classical antiquity, Aristotle saw that fossil seashells from rocks were similar to those found on the beach and deduced that the fossils were once part of living animals.^ Aristotle realized that fossil seashells from rocks were similar to those found on the beach, indicating the fossils were once living animals.

^ In many locations in the world are found extensive rock strata containing sometimes billions of fossilized animals, frequently densely packed together.
  • Geological Evidences for a Flood 17 January 2010 12:35 UTC www.cs.unc.edu [Source type: FILTERED WITH BAYES]

^ The geographic boundary between rocks of the Pacific Basin, which are basaltic, and those around the rim of the basin, which are in part andesitic.
  • Department of Geological & Atmospheric Sciences 3 February 2010 15:51 UTC www.ge-at.iastate.edu [Source type: FILTERED WITH BAYES]
  • Department of Geological & Atmospheric Sciences 3 February 2010 15:51 UTC www.ge-at.iastate.edu [Source type: FILTERED WITH BAYES]

.He reasoned that the positions of land and sea had changed over long periods of time.^ He deduced that the positions of land and sea had changed and these changes occurred over long periods of time.

^ The emails stretch from 1996 to last year and have been a key element in measuring climate change over long periods.
  • Tips & Notes to WUWT « Watts Up With That? 3 February 2010 15:51 UTC wattsupwiththat.com [Source type: FILTERED WITH BAYES]

^ A vague term generally used to refer to evolution on a grand scale, or over long periods of time.
  • Evolution: Glossary 3 February 2010 15:51 UTC www.pbs.org [Source type: Academic]

.Leonardo da Vinci concurred with Aristotle's view that fossils were the remains of ancient life.^ Leonardo da Vinci concurred with Aristotle's view that fossils were the remains of ancient life.

^ Faunal succession: The evolutionary sequence of life forms, especially as recorded by the fossil remains in a stratigraphic sequence.
  • Glossary of Geological Terms 17 January 2010 12:35 UTC www.geotech.org [Source type: FILTERED WITH BAYES]

^ Paleontology: The science of fossils, of ancient life-forms, and their evolution.
  • Glossary of Geological Terms 17 January 2010 12:35 UTC www.geotech.org [Source type: FILTERED WITH BAYES]

[5]
.The 11th-century Persian geologist Avicenna (Ibn Sina) examined various fossils and deduced that they originated from the petrifaction of plants and animals.^ The identification of strata by the fossils they contained, pioneered by William Smith , Georges Cuvier , Jean d'Omalius d'Halloy and Alexandre Brogniart in the early 19th century, enabled geologists to divide Earth history more precisely.

^ One of the principles underlying geologic time scales was the principle of superposition of strata, first proposed in the 11th century by the Persian geologist , Avicenna (Ibn Sina).

^ In a local area, biostratigraphic units may have subunits that are recognized by variations in physical and chemical properties even though they share similar fossil assemblages.
  • Geological Background 3 February 2010 15:51 UTC uts.cc.utexas.edu [Source type: FILTERED WITH BAYES]

[6] .He also first proposed one of the principles underlying geologic time scales: the law of superposition of strata.^ The geological time scale is far from dogma.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

^ A proposal for a creationist geological time scale.
  • OPPOSITION TO CREATIONISM 7 OF 9 3 February 2010 15:51 UTC www.csun.edu [Source type: Academic]

^ Geologic Time Scale Geologic time scale .

While discussing the origins of mountains in The Book of Healing in 1027, he outlined the principle as follows:[7][8]
.
It is also possible that the sea may have happened to flow little by little over the land consisting of both plain and mountain, and then have ebbed away from it.^ "It is also possible that the sea may have happened to flow little by little over the land consisting of both plain and mountain, and then have ebbed away from it.

^ It is possible that each time the land was exposed by the ebbing of the sea a layer was left, since we see that some mountains appear to have been piled up layer by layer, and it is therefore likely that the clay from which they were formed was itself at one time arranged in layers.

^ Rip current: A current that flows strongly away from the sea shore through gaps in the surf zone at intervals along the shoreline.
  • Glossary of Geological Terms 17 January 2010 12:35 UTC www.geotech.org [Source type: FILTERED WITH BAYES]

... .It is possible that each time the land was exposed by the ebbing of the sea a layer was left, since we see that some mountains appear to have been piled up layer by layer, and it is therefore likely that the clay from which they were formed was itself at one time arranged in layers.^ It is possible that each time the land was exposed by the ebbing of the sea a layer was left, since we see that some mountains appear to have been piled up layer by layer, and it is therefore likely that the clay from which they were formed was itself at one time arranged in layers.

^ Tyrannosaurs , Titanosaurs , duck bills , and horned dinosaurs ) evolve on land, as do Eusuchia ( modern crocodilians ); and mosasaurs and modern sharks appear in the sea.

^ In Namibia: 540 Ma: Rise of the Damara Granites, Moon Landscape Rocks , Rossing Mountain, Armour plated fish appear in the seas with the first shell fish.
  • Geological Time Scale Namibia 17 January 2010 12:35 UTC www.namibia-1on1.com [Source type: FILTERED WITH BAYES]

.One layer was formed first, then at a different period, a further was formed and piled, upon the first, and so on.^ The evolving marine life of the Ordovician becomes even more diverse and this period records the first appearance of vertebrates in the form of ostracoderms, jawless, backboned fish.
  • Geological Background 3 February 2010 15:51 UTC uts.cc.utexas.edu [Source type: FILTERED WITH BAYES]

^ As predicted by evolutionary theory Humans are similar to our closest cousins, chimpanzees and only differ by one amino acid to our further away cousins, the Rhesus monkeys.
  • Victoria Advocate | "Why We Shouldn't Teach Creationism" by Crobar 3 February 2010 15:51 UTC www.victoriaadvocate.com [Source type: Academic]

^ Isotope: One of several forms of one element, all having the same number of protons in the nucleus, but differing in their number of neutrons and thus atomic weight.
  • Glossary of Geological Terms 17 January 2010 12:35 UTC www.geotech.org [Source type: FILTERED WITH BAYES]

.Over each layer there spread a substance of different material, which formed a partition between it and the next layer; but when petrification took place something occurred to the partition which caused it to break up and disintegrate from between the layers (possibly referring to unconformity).^ Over each layer there spread a substance of different material, which formed a partition between it and the next layer; but when petrification took place something occurred to the partition which caused it to break up and disintegrate from between the layers (possibly referring to unconformity).

^ Duricrust A general term for a hard crust on or near the surface of a soil formed in a semi-arid climate and is made up of material such as calcrete and silcrete .
  • Glossary of Common Geoscience Terms - Geoscience Australia 17 January 2010 12:35 UTC www-a.ga.gov.au [Source type: FILTERED WITH BAYES]

^ The presence of planktonic forms, aquatic macrophytes, and marsh plants indicates that deposition of the sediments took place in a body of water, probably a pond or lake.

... .As to the beginning of the sea, its clay is either sedimentary or primeval, the latter not being sedimentary.^ Sedimentary rocks are those that were formed at the Earth’s surface, either by accumulation and cementation of fragments of rocks, minerals, and organisms, or as precipitates from sea water, surface water or ground water.
  • GEOLOGY OF FLORIDA 3 February 2010 15:51 UTC www.clas.ufl.edu [Source type: FILTERED WITH BAYES]

.It is probable that the sedimentary clay was formed by the disintegration of the strata of mountains.^ Shale A fine-grained sedimentary rock formed by the consolidation of clay or mud.
  • Glossary of Common Geoscience Terms - Geoscience Australia 17 January 2010 12:35 UTC www-a.ga.gov.au [Source type: FILTERED WITH BAYES]

Such is the formation of mountains.
.His contemporary, Abu Rayhan Biruni (973-1048), discovered the existence of shells and fossils in regions that once were seas and later became dry land, such as the Indian subcontinent.^ The largest two groups of index fossils are the brachiopods (bivalve shells) and mollusks (various kinds of other shell creatures such as snails, nautiloids, etc).
  • The Historical Development of the Old-Earth Geological Time-Scale - Answers in Genesis 3 February 2010 15:51 UTC www.answersingenesis.org [Source type: FILTERED WITH BAYES]

^ Florida Bay, stranded as dry land during glacial periods, was most likely a Pleistocene lagoon during high stands of sea level.
  • GEOLOGY OF FLORIDA 3 February 2010 15:51 UTC www.clas.ufl.edu [Source type: FILTERED WITH BAYES]

^ Transgression: A rise in sea level relative to the land which causes areas to be submerged and marine deposition to begin in that region.
  • Glossary of Geological Terms 17 January 2010 12:35 UTC www.geotech.org [Source type: FILTERED WITH BAYES]

.Based on this evidence, he realized that the Earth is constantly evolving and proposed that the Earth had an age, but that its origin was too distant to measure.^ While creationists had been proposing dates of around six or seven thousand years for the age of the Earth based on their Christian heritage, early geologists were suggesting millions of years for geologic periods with some even suggesting a virtually infinite age for the Earth.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ An excellent introduction to radiometric dating can also be found in the talk.origins FAQ archive: Age of the Earth FAQ Isochron dating FAQ .
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

^ "That's not a real estimate but something based on just a few measurements," Abbott said.
  • YELLOWSTONE SUPERVOLCANO GETTING READY TO BLOW ITS CORK 3 February 2010 15:51 UTC www.earthmountainview.com [Source type: FILTERED WITH BAYES]

[9] Later in the 11th century, the Chinese naturalist, Shen Kuo (1031–1095), also recognized the concept of 'deep time'.[10]
.The principles underlying geologic (geological) time scales were later laid down by Nicholas Steno in the late 17th century.^ The geological time scale is far from dogma.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

^ Earth history mapped to 24 hours The principles underlying geologic (geological) time scales were laid down by Nicholas Steno in the late 17th century.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ The calibration of the geological time scale is extended into the late Paleogene.
  • e-Prints Soton - Extending the geological calibration of the geological time scale 3 February 2010 15:51 UTC eprints.soton.ac.uk [Source type: Academic]

.Steno argued that rock layers (or strata) are laid down in succession, and that each represents a "slice" of time.^ Steno argued that rock layers (or strata) are laid down in succession, and that each represents a "slice" of time.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ Thus, the rock layer cannot represent a long period of time.
  • Geological Evidences for a Flood 17 January 2010 12:35 UTC www.cs.unc.edu [Source type: FILTERED WITH BAYES]

^ The layers of rock are known as "strata", and the study of their succession is known as "stratigraphy".
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

.He also formulated the law of superposition, which states that any given stratum is probably older than those above it and younger than those below it.^ The stratum should not be younger than the object.
  • Geological Background 3 February 2010 15:51 UTC uts.cc.utexas.edu [Source type: FILTERED WITH BAYES]

^ He also formulated the principle of superposition , which states that any given stratum is probably older than those above it and younger than those below it.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ One fundamental principle of relative age dating is the Law of Superposition , which states that: in any sequence of sedimentary strata that has not been disturbed by folding or overturning since accumulation, the youngest stratum is at the top and the oldest is at the bottom.
  • GEOLOGY OF FLORIDA 3 February 2010 15:51 UTC www.clas.ufl.edu [Source type: FILTERED WITH BAYES]

.While Steno's principles were simple, applying them to real rocks proved complex.^ While Steno's principles were simple, applying them to real rocks proved complex.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ Fundamental to stratigraphy are a set of simple principles, based on elementary geometry, empirical observation of the way these rocks are deposited today, and gravity.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

^ The stock explanation in such cases is that a "thrust fault" allowed older strata containing simple fossils to be slid out on top of younger rocks contain complex fossils.
  • Geological Evidences for a Flood 17 January 2010 12:35 UTC www.cs.unc.edu [Source type: FILTERED WITH BAYES]

Over the course of the 18th century geologists realized that:
  1. Sequences of strata were often eroded, distorted, tilted, or even inverted after deposition;
  2. Strata laid down at the same time in different areas could have entirely different appearances;
  3. The strata of any given area represented only part of the Earth's long history.
A comparative geological timescale
.The first serious attempts to formulate a geological time scale that could be applied anywhere on Earth were made in the late 18th century.^ The geological time scale is far from dogma.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

^ The calibration of the geological time scale is extended into the late Paleogene.
  • e-Prints Soton - Extending the geological calibration of the geological time scale 3 February 2010 15:51 UTC eprints.soton.ac.uk [Source type: Academic]

^ The first serious attempts to formulate a geological time scale that could be applied anywhere on Earth took place in the late 18th century.

.The most influential of those early attempts (championed by Abraham Werner, among others) divided the rocks of the Earth's crust into four types: Primary, Secondary, Tertiary, and Quaternary.^ The most influential of those early attempts (championed by Abraham Werner , among others) divided the rocks of the Earth's crust into four types: Primary, Secondary, Tertiary, and Quaternary.

^ (The other types of rock are igneous and metamorphic.

^ One of the earliest (1759) relative time scales based upon this observation was the subdivision of the Earth's stratigraphy (and therefore its history), into the "Primary", "Secondary", "Tertiary", and later (1854) "Quaternary" strata based mainly on characteristic rock types in Europe.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

.Each type of rock, according to the theory, formed during a specific period in Earth history.^ Each type of rock, according to the theory, formed during a specific period in Earth history.

^ A lake formed during a pluvial period.
  • Department of Geological & Atmospheric Sciences 3 February 2010 15:51 UTC www.ge-at.iastate.edu [Source type: FILTERED WITH BAYES]
  • Department of Geological & Atmospheric Sciences 3 February 2010 15:51 UTC www.ge-at.iastate.edu [Source type: FILTERED WITH BAYES]

^ Thus, only in newly forming or liquid rock would the molecules be able to line up with the current polarity of the Earth.

.It was thus possible to speak of a "Tertiary Period" as well as of "Tertiary Rocks."^ It was thus possible to speak of a "Tertiary Period" as well as of "Tertiary Rocks."

^ Indeed, "Tertiary" (now Paleocene-Pliocene) and "Quaternary" (now Pleistocene-Holocene) remained in use as names of geological periods well into the 20th century.

^ Historically, the Cenozoic has been divided up into the Quaternary and Tertiary sub-eras, as well as the Neogene and Paleogene periods.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

.Indeed, "Tertiary" (now Paleocene-Pliocene) and "Quaternary" (now Pleistocene-Holocene) remained in use as names of geological periods well into the 20th century.^ Indeed, "Tertiary" (now Paleocene-Pliocene) and "Quaternary" (now Pleistocene-Holocene) remained in use as names of geological periods well into the 20th century.

^ Example: the Pleistocene epoch is in the Quaternary period.
  • Department of Geological & Atmospheric Sciences 3 February 2010 15:51 UTC www.ge-at.iastate.edu [Source type: FILTERED WITH BAYES]
  • Department of Geological & Atmospheric Sciences 3 February 2010 15:51 UTC www.ge-at.iastate.edu [Source type: FILTERED WITH BAYES]

^ In 1977, the Global Commission on Stratigraphy (now the International Commission on Stratigraphy ) started an effort to define global references ( Global Boundary Stratotype Sections and Points ) for geologic periods and faunal stages.

.The Neptunist theories popular at this time (expounded by Werner) proposed that all rocks had precipitated out of a single enormous flood.^ In opposition to the then-popular Neptunist theories expounded by Werner (that all rocks had precipitated out of a single enormous flood), a major shift in thinking came with the reading by James Hutton of his Theory of the Earth; or, an Investigation of the Laws Observable in the Composition, Dissolution, and Restoration of Land Upon the Globe before the Royal Society of Edinburgh in March and April 1785, events which "as things appear from the perspective of the twentieth century, James Hutton in those reading became the founder of modern geology" [10] What Hutton proposed was that the interior of the Earth was hot, and that this heat was the engine which drove the creation of new rock: land was eroded by air and water and deposited as layers in the sea; heat then consolidated the sediment into stone, and uplifted it into new lands.

^ Even the Grand Canyon, which probably is the greatest single sequence of rocks anywhere on the Earth's surface and spans a period of time of two billion years has gaps.
  • GG101 Geologic Time 3 February 2010 15:51 UTC honolulu.hawaii.edu [Source type: FILTERED WITH BAYES]

^ He knew that his proposal of small random changes guided by natural selection would require enormous amounts of time for the production of successful complex organisms.
  • SOME QUESTIONS ABOUT GEOCHRONOLOGY 3 February 2010 15:51 UTC origins.swau.edu [Source type: Academic]

.A major shift in thinking came when James Hutton presented his Theory of the Earth; or, an Investigation of the Laws Observable in the Composition, Dissolution, and Restoration of Land Upon the Globe before the Royal Society of Edinburgh in March and April 1785. It has been said that "as things appear from the perspective of the twentieth century, James Hutton in those reading became the founder of modern geology"[11] Hutton proposed that the interior of the Earth was hot, and that this heat was the engine which drove the creation of new rock: land was eroded by air and water and deposited as layers in the sea; heat then consolidated the sediment into stone, and uplifted it into new lands.^ In opposition to the then-popular Neptunist theories expounded by Werner (that all rocks had precipitated out of a single enormous flood), a major shift in thinking came with the reading by James Hutton of his Theory of the Earth; or, an Investigation of the Laws Observable in the Composition, Dissolution, and Restoration of Land Upon the Globe before the Royal Society of Edinburgh in March and April 1785, events which "as things appear from the perspective of the twentieth century, James Hutton in those reading became the founder of modern geology" [10] What Hutton proposed was that the interior of the Earth was hot, and that this heat was the engine which drove the creation of new rock: land was eroded by air and water and deposited as layers in the sea; heat then consolidated the sediment into stone, and uplifted it into new lands.

^ J. Hutton, Theory of the Earth: with proofs and illustrations.
  • e-Prints Soton - Extending the geological calibration of the geological time scale 3 February 2010 15:51 UTC eprints.soton.ac.uk [Source type: Academic]

^ Sediments deposited from flood water on the flood plain.
  • Department of Geological & Atmospheric Sciences 3 February 2010 15:51 UTC www.ge-at.iastate.edu [Source type: FILTERED WITH BAYES]
  • Department of Geological & Atmospheric Sciences 3 February 2010 15:51 UTC www.ge-at.iastate.edu [Source type: FILTERED WITH BAYES]

.This theory was dubbed "Plutonist" in contrast to the flood-oriented theory.^ This theory was dubbed "Plutonist" in contrast to the flood-oriented theory.

.The identification of strata by the fossils they contained, pioneered by William Smith, Georges Cuvier, Jean d'Omalius d'Halloy, and Alexandre Brogniart in the early 19th century, enabled geologists to divide Earth history more precisely.^ Timelines of earth history according to the three views of the early 19th century.
  • The Historical Development of the Old-Earth Geological Time-Scale - Answers in Genesis 3 February 2010 15:51 UTC www.answersingenesis.org [Source type: FILTERED WITH BAYES]

^ The identification of strata by the fossils they contained, pioneered by William Smith , Georges Cuvier , Jean d'Omalius d'Halloy and Alexandre Brogniart in the early 19th century, enabled geologists to divide Earth history more precisely.

^ Earth history is divided.
  • GEOLOGY OF FLORIDA 3 February 2010 15:51 UTC www.clas.ufl.edu [Source type: FILTERED WITH BAYES]

It also enabled them to correlate strata across national (or even continental) boundaries. .If two strata (however distant in space or different in composition) contained the same fossils, chances were good that they had been laid down at the same time.^ The sex with two of the same kind of chromosomes (females in mammals, because they are XX).
  • Evolution: Glossary 3 February 2010 15:51 UTC www.pbs.org [Source type: Academic]

^ So-called “living fossils” are strong evidence of the fallacy of this assumption that absence of the fossils in a particular layer of rock means that the creature did not live at the same time as the fossilized creatures in that layer.
  • The Historical Development of the Old-Earth Geological Time-Scale - Answers in Genesis 3 February 2010 15:51 UTC www.answersingenesis.org [Source type: FILTERED WITH BAYES]

^ However, the model provides no basis for assuming a time correlation on an inter-regional scale based on fossil evidence because this would require each index fossil to be deposited worldwide at the same time during the whole of the Flood event.
  • Tas Walker's Biblical Geology - Brisbane basement 17 January 2010 12:35 UTC biblicalgeology.net [Source type: FILTERED WITH BAYES]

.Detailed studies between 1820 and 1850 of the strata and fossils of Europe produced the sequence of geological periods still used today.^ Many of their biblical and geological objections are similar to arguments used by young-earth geologists today.
  • The Historical Development of the Old-Earth Geological Time-Scale - Answers in Genesis 3 February 2010 15:51 UTC www.answersingenesis.org [Source type: FILTERED WITH BAYES]

^ And without a calibration of geologic time, we can't study the rates of geologic change that are used to make forecasts about future events.
  • GG101 Geologic Time 3 February 2010 15:51 UTC honolulu.hawaii.edu [Source type: FILTERED WITH BAYES]

^ This was the only representation of geologic time before radioactive decay was discovered, but it is still widely used in the current geologic practice and research.
  • Geologic ages of earth history - encyclopedia article - Citizendium 3 February 2010 15:51 UTC en.citizendium.org [Source type: FILTERED WITH BAYES]

.The process was dominated by British geologists, and the names of the periods reflect that dominance.^ British geologists dominated the process, and the names of the periods reflect that dominance.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ The "Permian" was named after Perm , Russia , because it was defined using strata in that region by a British geologist Roderick Murchison .
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ The "Devonian" was named for the English county of Devon , and the name "Carboniferous" was simply an adaptation of "the Coal Measures," the old British geologists' term for the same set of strata.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

.The "Cambrian," (the Roman name for Wales) and the "Ordovician," and "Silurian", named after ancient Welsh tribes, were periods defined using stratigraphic sequences from Wales.^ The "Cambrian," "Ordovician," and "Silurian" periods were named after ancient British tribes (and defined using stratigraphic sequences from Wales).
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ The "Permian" was named after Perm , Russia , because it was defined using strata in that region by a British geologist Roderick Murchison .
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ Cambrian (about 545 to 495 Ma) Ordovician (about 495 to 443 Ma) Silurian (about 443 to 417 Ma) Devonian (about 417 to 354 Ma) Carboniferous (about 354 to 290 Ma) Permian (about 290 to 248.2 Ma) Periods of the Mesozoic Era .

[12] .The "Devonian" was named for the English county of Devon, and the name "Carboniferous" was simply an adaptation of "the Coal Measures," the old British geologists' term for the same set of strata.^ The "Devonian" was named for the English county of Devon , and the name "Carboniferous" was simply an adaptation of "the Coal Measures," the old British geologists' term for the same set of strata.

^ The "Permian" was named after Perm , Russia , because it was defined using strata in that region by a British geologist Roderick Murchison .
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ British geologists dominated the process, and the names of the periods reflect that dominance.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

.The "Permian" was named after Perm, Russia, because it was defined using strata in that region by Scottish geologist Roderick Murchison.^ The "Permian" was named after Perm , Russia , because it was defined using strata in that region by a British geologist Roderick Murchison .
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ The "Devonian" was named for the English county of Devon , and the name "Carboniferous" was simply an adaptation of "the Coal Measures," the old British geologists' term for the same set of strata.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ The "Cretaceous" (from Latin creta meaning ' chalk ') as a separate period was first defined by a Belgian geologist Jean d'Omalius d'Halloy in 1822, using strata in the Paris basin [1] and named for the extensive beds of chalk ( calcium carbonate deposited by the shells of marine invertebrates ).
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

.However, some periods were defined by geologists from other countries.^ However, some periods were defined by geologists from other countries.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ Geologists tend to talk in terms of Upper/Late, Lower/Early and Middle parts of periods and other units , such as "Upper Jurassic ", and "Middle Cambrian ".
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

.The "Triassic" was named in 1834 by a German geologist Friedrich Von Alberti from the three distinct layers (Latin trias meaning triad) —red beds, capped by chalk, followed by black shales— that are found throughout Germany and Northwest Europe, called the 'Trias'. The "Jurassic" was named by a French geologist Alexandre Brogniart for the extensive marine limestone exposures of the Jura Mountains.^ The "Jurassic" was named by a French geologist Alexandre Brogniart for the extensive marine limestone exposures of the Jura Mountains .

^ The "Triassic" was named in 1834 by a German geologist Friedrich Von Alberti from the three distinct layers (Latin trias meaning triad) — red beds , capped by chalk , followed by black shales — that are found throughout Germany and Northwest Europe, called the 'Trias'.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ The "Triassic" was named in 1834 by a German geologist Friedrich Von Alberti from the three distinct layers ( Latin trias meaning triad) red beds , capped by chalk , followed by black shales that are found throughout Germany and Northwest Europe , called the 'Trias'.

.The "Cretaceous" (from Latin creta meaning 'chalk') as a separate period was first defined by Belgian geologist Jean d'Omalius d'Halloy in 1822, using strata in the Paris basin[13] and named for the extensive beds of chalk (calcium carbonate deposited by the shells of marine invertebrates).^ The "Cretaceous" (from Latin creta meaning ' chalk ') as a separate period was first defined by a Belgian geologist Jean d'Omalius d'Halloy in 1822, using strata in the Paris basin [12] and named for the extensive beds of chalk ( calcium carbonate deposited by the shells of marine invertebrates ).

^ The "Cretaceous" (from Latin creta meaning ' chalk ') as a separate period was first defined by a Belgian geologist Jean d'Omalius d'Halloy in 1822, using strata in the Paris basin [1] and named for the extensive beds of chalk ( calcium carbonate deposited by the shells of marine invertebrates ).
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ The "Permian" was named after Perm , Russia , because it was defined using strata in that region by a Scottish geologist Roderick Murchison .

.British geologists were also responsible for the grouping of periods into Eras and the subdivision of the Tertiary and Quaternary periods into epochs.^ Cenozoic is a grouping of Quaternary and Tertiary periods.
  • Galactic Geologic Interval Theory - Astronomy.com Forums 17 January 2010 12:35 UTC cs.astronomy.com [Source type: FILTERED WITH BAYES]

^ Eons are divided into Eras, which are in turn divided into Periods, Epochs and Stages.
  • Geologic time scale - Paleontology Wiki 3 February 2010 15:51 UTC paleontology.wikia.com [Source type: FILTERED WITH BAYES]

^ The eras have since been renamed and Tertiary and Quaternary were merged into the Cenozoic as “periods” not eras.
  • Geologic ages of earth history - encyclopedia article - Citizendium 3 February 2010 15:51 UTC en.citizendium.org [Source type: FILTERED WITH BAYES]

.When William Smith and Sir Charles Lyell first recognized that rock strata represented successive time periods, time scales could be estimated only very imprecisely since various kinds of rates of change used in estimation were highly variable.^ When William Smith and Sir Charles Lyell first recognized that rock strata represented successive time periods, time scales could be estimated only very imprecisely since various kinds of rates of change used in estimation were highly variable.

^ The next phase of development in this field was from a canal builder in 19th century England, William Smith , In 1815 Smith produced a geologic map of England demonstrating the principle of biotic succession : The different types of animals that had lived and died in that region over immense periods of time had changed and left their fossils attesting to their existence.
  • Geologic ages of earth history - encyclopedia article - Citizendium 3 February 2010 15:51 UTC en.citizendium.org [Source type: FILTERED WITH BAYES]

^ Sequences of strata were often eroded, distorted, tilted, or even inverted after deposition ; Strata laid down at the same time in different areas could have entirely different appearances; The strata of any given area represented only part of the Earth's long history.

.While creationists had been proposing dates of around six or seven thousand years for the age of the Earth based on the Bible, early geologists were suggesting millions of years for geologic periods with some even suggesting a virtually infinite age for the Earth.^ The Quaternary Period encompasses the last 1.8-million years of geologic history.
  • GEOLOGY OF FLORIDA 3 February 2010 15:51 UTC www.clas.ufl.edu [Source type: FILTERED WITH BAYES]

^ Is it really a record of millions and even billions of years of Earth's history?

^ Geologic ages of earth history .
  • Geologic ages of earth history - encyclopedia article - Citizendium 3 February 2010 15:51 UTC en.citizendium.org [Source type: FILTERED WITH BAYES]

.Geologists and paleontologists constructed the geologic table based on the relative positions of different strata and fossils, and estimated the time scales based on studying rates of various kinds of weathering, erosion, sedimentation, and lithification.^ A recent geological time scale, based on Harland et al.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

^ Geologic time scale [hide] .

^ A Geologic Time Scale: 1982 edition.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

.Until the discovery of radioactivity in 1896 and the development of its geological applications through radiometric dating during the first half of the 20th century (pioneered by such geologists as Arthur Holmes) which allowed for more precise absolute dating of rocks, the ages of various rock strata and the age of the Earth were the subject of considerable debate.^ Until the discovery of radioactivity in 1896 and the development of its geological applications through radiometric dating during the first half of the 20th century (pioneered by such geologists as Arthur Holmes ) which allowed for more precise absolute dating of rocks, the ages of various rock strata and the age of the Earth were the subject of considerable debate.

^ The secrets of Earth’s age are hidden in its rocks.
  • GEOLOGY OF FLORIDA 3 February 2010 15:51 UTC www.clas.ufl.edu [Source type: FILTERED WITH BAYES]

^ Geologic ages of earth history .
  • Geologic ages of earth history - encyclopedia article - Citizendium 3 February 2010 15:51 UTC en.citizendium.org [Source type: FILTERED WITH BAYES]

.The first geologic time scale was eventually published in 1913 by the British geologist Arthur Holmes.^ A Geologic Time Scale: 1982 edition.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

^ Standard geologic column and time scale.
  • GEOLOGY OF FLORIDA 3 February 2010 15:51 UTC www.clas.ufl.edu [Source type: FILTERED WITH BAYES]

^ A Geologic Time Scale, 1989 edition.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

[14] .He greatly furthered the newly created discipline of geochronology and published the world renowned book The Age of the Earth in 1913 in which he estimated the Earth's age to be at least 1.6 billion years.^ The estimated age of Earth itself is over 4.6 billion years, an incomprehensibly vast period of time.
  • GG101 Geologic Time 3 February 2010 15:51 UTC honolulu.hawaii.edu [Source type: FILTERED WITH BAYES]

^ Potassium-40 has a half-life of 1.3 billion years, and with the help of argon-40, geologists have been able to estimate the age of volcanic layers above and below fossil and artifact remains in eastern Africa.

^ Although the long half-life allows theoretically permits the dating of the age of the earth, it is not useful for specimens younger than a few hundred thousand years...
  • Geological Background 3 February 2010 15:51 UTC uts.cc.utexas.edu [Source type: FILTERED WITH BAYES]

[15]
.In 1977, the Global Commission on Stratigraphy (now the International Commission on Stratigraphy) started an effort to define global references (Global Boundary Stratotype Sections and Points) for geologic periods and faunal stages.^ Stratigraphic boundaries are proposed to the sub-commission on a particular geologic stage who then submit their recommendations to the International Commission on Stratigraphy (ICS) for official acceptance.
  • Geologic ages of earth history - encyclopedia article - Citizendium 3 February 2010 15:51 UTC en.citizendium.org [Source type: FILTERED WITH BAYES]

^ The recommendations for Global Standard Stratotype-section and Points (GSSP) which demarcate the boundaries of the strata and ultimately define the age of the earth are processed through a sequence of stages.
  • Geologic ages of earth history - encyclopedia article - Citizendium 3 February 2010 15:51 UTC en.citizendium.org [Source type: FILTERED WITH BAYES]

^ Global definitions of chronostratigraphic boundaries are the purview of the International Union of Geological Sciences (IUGS).
  • Geologic ages of earth history - encyclopedia article - Citizendium 3 February 2010 15:51 UTC en.citizendium.org [Source type: FILTERED WITH BAYES]

.The commission's most recent work is described in the 2004 geologic time scale of Gradstein et al.^ The methods work too well most of the time.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

^ A recent geological time scale, based on Harland et al.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

^ A Geologic Time Scale: 1982 edition.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

[16]. A UML model for how the timescale is structured, relating it to the GSSP, is also available[17].

Table of geologic time

.The following table summarizes the major events and characteristics of the periods of time making up the geologic time scale.^ A Geologic Time Scale: 1982 edition.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

^ So scaling intervals to the Geologic Periods makes a nice correlation.
  • Galactic Geologic Interval Theory - Astronomy.com Forums 17 January 2010 12:35 UTC cs.astronomy.com [Source type: FILTERED WITH BAYES]

^ Standard geologic column and time scale.
  • GEOLOGY OF FLORIDA 3 February 2010 15:51 UTC www.clas.ufl.edu [Source type: FILTERED WITH BAYES]

.As above, this time scale is based on the International Commission on Stratigraphy.^ As above, this time scale is based on the International Commission on Stratigraphy.

^ The table of geologic time spans presented here agrees with the dates and nomenclature proposed by the International Commission on Stratigraphy , and uses the standard color codes of the United States Geological Survey .

^ In 1977, the Global Commission on Stratigraphy (now the International Commission on Stratigraphy ) started an effort to define global references ( Global Boundary Stratotype Sections and Points ) for geologic periods and faunal stages.

.(See lunar geologic timescale for a discussion of the geologic subdivisions of Earth's moon.^ (See lunar geologic timescale for a discussion of the geologic subdivisions of Earth's moon.

^ It is easy to see that the mutual action between the moon and the earth must tend, in virtue of the tides, to diminish the rapidity of the earth's rotation, and increase the moment of the moon's motion round the earth.
  • Lord Kelvin | On Geological Time 17 January 2010 12:35 UTC zapatopi.net [Source type: Original source]

^ You see, there's really no need for supernatural intervention if time can explain the existing geologic features on Earth.
  • GG101 Geologic Time 3 February 2010 15:51 UTC honolulu.hawaii.edu [Source type: FILTERED WITH BAYES]

) .This table is arranged with the most recent geologic periods at the top, and the most ancient at the bottom.^ In geologic time starting with the most recent...
  • Lindsay Geologic Time Scale / Flashcards - Create Free Flashcards 3 February 2010 15:51 UTC www.proprofs.com [Source type: Academic]

^ Phanerozoic the most recent eon of geologic time beginning 570 million years ago and continuing to the present.
  • Department of Geological & Atmospheric Sciences 3 February 2010 15:51 UTC www.ge-at.iastate.edu [Source type: FILTERED WITH BAYES]
  • Department of Geological & Atmospheric Sciences 3 February 2010 15:51 UTC www.ge-at.iastate.edu [Source type: FILTERED WITH BAYES]

^ Map courtesy of U.S. Geological Survey The U.S. Geological Survey recently completed a four-year project mapping the bottom of Yellowstone Lake in Yellowstone National Park.
  • YELLOWSTONE SUPERVOLCANO GETTING READY TO BLOW ITS CORK 3 February 2010 15:51 UTC www.earthmountainview.com [Source type: FILTERED WITH BAYES]

.The height of each table entry does not correspond to the duration of each subdivision of time.^ The height of each table entry does not correspond to the duration of each subdivision of time.

^ Period A geological time subdivision of an Era , during which the rocks of the corresponding system were formed.
  • Glossary of Common Geoscience Terms - Geoscience Australia 17 January 2010 12:35 UTC www-a.ga.gov.au [Source type: FILTERED WITH BAYES]

.The content of the table is based on the current official geologic time scale of the International Commission on Stratigraphy,[18] with the epoch names altered to the early/late format from lower/upper as recommended by the ICS when dealing with chronostratigraphy.^ The geological time scale is far from dogma.
  • Radiometric Dating and the Geological TimeScale 3 February 2010 15:51 UTC www.talkorigins.org [Source type: FILTERED WITH BAYES]

^ Table of geologic time .

^ A proposal for a creationist geological time scale.
  • OPPOSITION TO CREATIONISM 7 OF 9 3 February 2010 15:51 UTC www.csun.edu [Source type: Academic]

[3]

See also

References and footnotes

  1. ^ International Commission on Stratigraphy 2008:http://www.stratigraphy.org/column.php?id=Chart/Time%20Scale, retrieved 9 March 2009.
  2. ^ International Commission on Stratigraphy. "International Stratigraphic Chart". http://www.stratigraphy.org/upload/ISChart2009.pdf. Retrieved 2009-09-25. 
  3. ^ a b International Commission on Stratigraphy. "Chronostratigraphic Units." International Stratigraphic Guide. Accessed 14-DEC-2009. [1]
  4. ^ Statutes of the International Commission on Stratigraphy, retrieved 26 November 2009
  5. ^ Correlating Earth's History, Paul R. Janke
  6. ^ Rudwick, M. J. S. (1985). The Meaning of Fossils: Episodes in the History of Palaeontology. University of Chicago Press. p. 24. ISBN 0226731030. 
  7. ^ Munim M. Al-Rawi and Salim Al-Hassani (November 2002). "The Contribution of Ibn Sina (Avicenna) to the development of Earth sciences". FSTC. http://www.muslimheritage.com/uploads/ibnsina.pdf. Retrieved 2008-07-01. 
  8. ^ Stephen Toulmin and June Goodfield (1965), The Ancestry of Science: The Discovery of Time, p. 64, University of Chicago Press (cf. The Contribution of Ibn Sina to the development of Earth sciences)
  9. ^ Scheppler, Bill (2006), Al-Biruni: Master Astronomer and Muslim Scholar of the Eleventh Century, The Rosen Publishing Group, p. 86, ISBN 1404205128 
  10. ^ Sivin, Nathan (1995). Science in Ancient China: Researches and Reflections. Brookfield, Vermont: Ashgate Publishing Variorum series. III, 23–24. 
  11. ^ John McPhee, Basin and Range, New York:Farrar, Straus and Giroux, 1981, pp.95-100.
  12. ^ John McPhee, Basin and Range, pp.113-114.
  13. ^ (in Russian) Great Soviet Encyclopedia (3rd ed.). Moscow: Sovetskaya Enciklopediya. 1974. vol. 16, p. 50. 
  14. ^ Geologic Time Scale
  15. ^ How the discovery of geologic time changed our view of the world, Bristol University
  16. ^ Felix M. Gradstein, James G. Ogg, Alan G. Smith (Editors); A Geologic Time Scale 2004, Cambridge University Press, 2005, (ISBN 0-521-78673-8)
  17. ^ Cox & Richard, A formal model for the geologic time scale and global stratotype section and point, compatible with geospatial information transfer standards, Geosphere, volume 1, pp 119-137, Geological Society of America, 2005
  18. ^ International Commission on Stratigraphy. "International Stratigraphic Chart". http://www.stratigraphy.org/upload/ISChart2009.pdf. Retrieved 2009-09-25. 
  19. ^ Paleontologists often refer to faunal stages rather than geologic (geological) periods. The stage nomenclature is quite complex. See "The Paleobiology Database". http://flatpebble.nceas.ucsb.edu/cgi-bin/bridge.pl?action=startScale. Retrieved 2006-03-19.  for an excellent time ordered list of faunal stages.
  20. ^ a b Dates are slightly uncertain with differences of a few percent between various sources being common. This is largely due to uncertainties in radiometric dating and the problem that deposits suitable for radiometric dating seldom occur exactly at the places in the geologic column where they would be most useful. The dates and errors quoted above are according to the International Commission on Stratigraphy 2004 time scale. Dates labeled with a * indicate boundaries where a Global Boundary Stratotype Section and Point has been internationally agreed upon: see List of Global Boundary Stratotype Sections and Points for a complete list.
  21. ^ a b Historically, the Cenozoic has been divided up into the Quaternary and Tertiary sub-eras, as well as the Neogene and Paleogene periods. The 2009 version of the ICS time chart recognizes a slightly extended Quaternary as well as the Paleogene and a truncated Neogene, the Tertiary having been demoted to informal status.
  22. ^ a b c d e f For more information on this, see the following articles: Earth's atmosphere, carbon dioxide, Carbon dioxide in the Earth's atmosphere, Image:Phanerozoic_Carbon_Dioxide.png, Image:65 Myr Climate Change.png, Image:Five Myr Climate Change.png, and Template:DF temperature
  23. ^ The start time for the Holocene epoch is here given as 11,430 years ago ± 130 years (that is, between 9610 BC-9560 BC and 9350 BC-9300 BC). For further discussion of the dating of this epoch, see Holocene.
  24. ^ a b In North America, the Carboniferous is subdivided into Mississippian and Pennsylvanian Periods.
  25. ^ The Precambrian is also known as Cryptozoic.
  26. ^ a b c d e f g h i j k l m n The Proterozoic, Archean and Hadean are often collectively referred to as the Precambrian Time or sometimes, also the Cryptozoic.
  27. ^ a b c d e f g h i j k l Defined by absolute age (Global Standard Stratigraphic Age).
  28. ^ The age of the oldest measurable craton, or continental crust, is dated to 3600-3800 Ma
  29. ^ Though commonly used, the Hadean is not a formal eon and no lower bound for the Archean and Eoarchean have been agreed upon. The Hadean has also sometimes been called the Priscoan or the Azoic. Sometimes, the Hadean can be found to be subdivided according to the lunar geologic time scale. These eras include the Cryptic and Basin Groups (which are subdivisions of the pre-Nectarian era), Nectarian, and Early Imbrian units.
  30. ^ a b c d These unit names were taken from the Lunar geologic timescale and refer to geologic events that did not occur on Earth. Their use for Earth geology is unofficial.
  31. ^ Bowring, Samuel A. (1999). "Priscoan (4.00-4.03 Ga) orthogneisses from northwestern Canada". Contributions to Mineralogy and Petrology 134: 3. doi:10.1007/s004100050465.  The oldest rock on earth is the Acasta Gneiss, and it dates to 4.03 Ga, located in the Northwest Territories of Canada.
  32. ^ http://www.geology.wisc.edu/%7Evalley/zircons/Wilde2001Nature.pdf

External links

.

Citable sentences

Up to date as of December 26, 2010

Here are sentences from other pages on Geologic time scale, which are similar to those in the above article.








Got something to say? Make a comment.
Your name
Your email address
Message