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Encyclopedia > Paleoclimatology

Paleoclimatology is the study of climate change taken on the scale of the entire history of the Earth.

Contents


Techniques of paleoclimatology

Paleoclimatologists employ a wide variety of skills to arrive at their theories and conclusions.


Glaciers are a widely employed instrument in Paleoclimatology. The ice in glaciers has hardened into an identifiable pattern, with each year leaving a distinct layer in an ice core. It is estimated that the polar ice caps have 100,000 of these layers or more. Austrias longest glacier, the Pasterze, winds its 8 km (5 mile) route at the foot of Austrias highest mountain, the Grossglockner A glacier is a large, long-lasting river of ice that is formed on land and moves in response to gravity. ... Ice Core sample taken from drill. ...

  • Inside of these layers scientists have found pollen, allowing them to estimate the total amount of plant growth of that year by the pollen count. The thickness of the layer can help to determine the amount of rainfall that year.
  • Because evaporation rates of water molecules with slightly heavier isotopes of hydrogen and oxygen are slightly different during warmer and colder periods, changes in the average temperature of the ocean surface are reflected in slightly different ratios between those isotopes. Various cycles in those isotope ratios have been detected.

Petrified tree rings give Paleoclimatology data over a much larger stretch of time. The fossil itself is dated with radioactive dating within a wide margin of error. The rings themselves can give some information about rainfall and temperature during that epoch. SEM image of pollen grains from a variety of common plants: sunflower (Helianthus annuus), morning glory (Ipomea purpurea), hollyhock (Sildalcea malviflora), lily (Lilium auratum), primrose (Oenothera fruticosa), and castor bean (Ricinus communis). ... // Isotopes are forms of an element whose nuclei have the same atomic number–-the number of protons in the nucleus--but different mass numbers because they contain different numbers of neutrons. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... Petrified log at the Petrified Forest National Park A petrified tree from California Petrified wood is a type of fossil, in which the tissues of a dead plant are replaced with minerals (most often a silicate, such as quartz). ... A fossil Ammonite Fossils (from Latin fossus, literally having been dug up) are the mineralized or otherwise preserved remains or traces (such as footprints) of animals, plants, and other organisms. ... Radiometric dating is a technique used to date materials based on a knowledge of the decay rates of naturally occurring isotopes, and the current abundances. ... A division of geologic time less than a period and greater than an age. ...


Sediment layers have been studied, particularly those in the bottom of lakes and oceans. Characteristics of preserved vegetation, animals, pollen, and isotope ratios provide information. Sediment is any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of water or other liquid. ...


Sedimentary rock layers provide a more compressed view of climate, as each layer of sediment is made over a period of hundreds of thousands to millions of years. Scientists can get a grasp of long term climate by studying sedimentary rock. Some scientists believe each layer designates a major change in climate. Two types of sedimentary rock: limey shale overlaid by limestone. ...


Planet's timeline

Main article: geologic time scale

Some of the mile stones that mark the history of the planet are as follows (Ma = Millions of years ago): The geologic time scale is used by geologists and other scientists to describe the timing and relationships between events that have occurred during the history of the Earth. ...

4,000 Ma earliest biogenic carbon
3,700 Ma oldest rocks
3,500 Ma oldest stromatolites
3,500 Ma first evidence of sex [ref. Origins of Sex : Three Billion Years of Genetic Recombination]
3,450 Ma earliest bacteria
3,800 Ma banded iron formations (with reduced iron)
3,000 Ma earliest precambrian ice ages [need ref]
[?] Chuos Tillites of South-West Africa
[?] Sturtian Tillites of the Finders Range, South-central Australia
3,000 Ma earliest photosynthetic bacteria
2,700 Ma oldest chemical evidence of complex cells
2,300 Ma first green algae (eukaryotes)
2,000 Ma free oxygen in the atmosphere
2,000 Ma to 1600 Ma Gowganda tillites in the Canadian shield
1,700 Ma end of the banded iron formations and red beds become abundant (non-reducing atmosphere)
700 Ma first metazoans late Proterozoic (Ediacaran Epoch) - first skeletons
570 Ma to present Phanerozic Eon [history of the phanerozoic goes in here]
100 Ma development of the angiosperms (flowering plants)
2 Ma to present modern world and man's appearance on earth [whole history of man goes in here about 1/2000th of the time scale]
0.01 Ma end of the last ice age
0.001 Ma warming trend of the middle ages
0.0001 Ma end of the mini ice age
0.00022 Ma to present industrialized world and the introduction of man made greenhouse gases.

A biogenic substance is a substance produced by natural processes. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Atomic mass 12. ... Pre-Cambrian stromatolites in the Siyeh Formation, Glacier National Park. ... Look up Sex in Wiktionary, the free dictionary This article is about biological sexes — male, female, etc. ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... 2. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Atomic mass 55. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years For the animated movie, see Ice Age (movie). ... Tillite is lithified till. ... Tillite is lithified till. ... Leaf. ... A seaweed (Laurencia) up close: the branches are multicellular and only about 1 mm thick. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Protista A eukaryote (also spelled eucaryote) is an organism with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... Phyla Radiata Cnidaria Ctenophora - Comb jellies Bilateria Protostomia Acoelomorpha Platyhelminthes - Flatworms Nemertina - Ribbon worms Gastrotricha Gnathostomulida - Jawed worms Micrognathozoa Rotifera - Rotifers Acanthocephala Priapulida Kinorhyncha Loricifera Entoprocta Nematoda - Roundworms Nematomorpha - Horsehair worms Cycliophora Mollusca - Mollusks Sipuncula - Peanut worms Annelida - Segmented worms Tardigrada - Water bears Onychophora - Velvet worms Arthropoda - Insects, etc. ... Classes Magnoliopsida - Dicots Liliopsida - Monocots The flowering plants (also angiosperms or Magnoliophyta) are one of the major groups of modern plants, comprising those that produce seeds in specialized reproductive organs called flowers, where the ovulary or carpel is enclosed. ... The Medieval Warm Period (MWP) or Medieval Climate Optimum was an unusually warm period during the European Medieval period, lasting from about the 10th century to about the 14th century. ... The Little Ice Age (LIA) was a period of cooling lasting approximately from the 14th to the mid-19th centuries, although there is no generally agreed start or end date: some confine the period to 1550-1850. ... Top: Increasing atmospheric CO2 levels as measured in the atmosphere and ice cores. ...



Millions of Years

Various notable climate-related events

Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years For the animated movie, see Ice Age (movie). ... The Snowball Earth hypothesis attempts to explain a number of phenomena noted in the geological record by proposing that an ice age that took place in the Neoproterozoic was so severe that the Earths oceans froze over completely, with only heat from the Earths planetary core causing some... The Snowball Earth, also known as the Varangian glaciation, is a recent hypothesis, largely formulated by Paul F. Hoffman, Sturgis Hooper Professor of Geology at Harvard University. ... The name Hadean refers to the geologic period before 3800 million years ago (mya). ... The Paleoproterozoic is the first of the three sub-divisions of the Proterozoic occurring between 2500 to 1600 million years ago. ... The Permian-Triassic extinction event, labeled End P here, is the most significant extinction event in this plot for marine fossiliferous genera. ... The Permian is a geologic period that extends from about 299. ... The Triassic is a geologic period that extends from about 245 to 202 Ma (million years ago). ... Climate change during the last 65 million years. ... The Paleocene epoch (65-56 MYA) (early dawn of the recent) is the first geologic epoch of the Palaeogene period in the modern Cenozoic era. ... The Eocene epoch (56-34 Ma) is a major division of the geologic timescale and the second epoch of the Palaeogene period in the Cenozoic era. ... Three temperature records, the GRIP one clearly showing the Younger Dryas event at around 11 kyr BP The Younger Dryas stadial, named after the alpine / tundra wildflower Dryas octopetala, and also referred to as the Big Freeze [1], was a brief (approximately 1300 +/- 70year [1]) cold climate period following the... The Holocene Climate Optimum was a warm period during roughly the interval 7,000 to 5,000 years B.P.. This event has also been known by many other names, including: Hypisthermal, Altithermal, Climatic Optimum, Holocene Optimum, Holocene Thermal Maximum, and Holocene Megathermal. ... (8th millennium BC – 7th millennium BC – 6th millennium BC – other millennia) // Events Circa 7000 BC – Agriculture and settlement at Mehrgarh in South Asia. ... (31st century BC - 30th century BC - 29th century BC - other centuries) (4th millennium BC - 3rd millennium BC - 2nd millennium BC) Events 2925 - 2776 BC - First Dynasty wars in Egypt 2900 BC - Beginning of the Early Dynastic Period I in Mesopotamia. ... In the years 535 and 536, several remarkable aberrations in world climate took place. ... Events Beginning of the Western Wei Dynasty in China. ... Events June 8 - St. ... The Medieval Warm Period (MWP) or Medieval Climate Optimum was an unusually warm period during the European Medieval period, lasting from about the 10th century to about the 14th century. ... Events Persian scientist, Rhazes, distinguished smallpox from measles in the course of his writings. ... Events Beginning of the Renaissance. ... The Little Ice Age (LIA) was a period of cooling lasting approximately from the 14th to the mid-19th centuries, although there is no generally agreed start or end date: some confine the period to 1550-1850. ... Events Beginning of the Renaissance. ... 1800 (MDCCC) was an common year starting on Wednesday (see link for calendar). ... The Year Without a Summer, also known as the Poverty Year and Eighteen hundred and froze to death was 1816, in which severe summer climate abnormalities destroyed crops in Northern Europe and the American Northeast. ... 1816 was a leap year starting on Monday (see link for calendar). ... Global mean surface temperatures 1856 to 2005 Mean temperature anomalies during the period 1995 to 2004 with respect to the average temperatures from 1940 to 1980 Global warming is an increase in the average temperature of the Earths atmosphere and oceans. ... 1900 (MCM) was an exceptional common year starting on Monday. ...

History of the atmosphere

Earliest atmosphere

The earliest atmosphere of the Earth was probably stripped away by solar winds early in the history of the planet. These gases were later replaced by an atmosphere derived from outgassing from the Earth. Sometime during the late Archean Era an oxygen atmosphere began to develop from photosynthesizing algae.


Carbon dioxide and free oxygen

Free oxygen did not exist until about 1,700 Ma and this can be seen with the development of the red beds and the end of the banded iron formations. This signifies a shift from a reducing atmosphere to an oxidising atmosphere. The early atmosphere and hydrosphere (up until about 2,000 Ma) were devoid of free Oxygen. After photosynthesis developed, photoautotrophs began releasing O2. Phototrophs or photoautotrophs are photosynthetic algae, fungi, bacteria and cyanobacteria which build up carbon dioxide and water into organic cell materials using energy from sunlight. ...


The very early atmosphere of the earth contained mostly carbon dioxide (CO2) : about 80%. This gradually dropped to about 20% by 3,500 Ma. This coincides with the development of the first bacteria about 3,500 Ma. By the time of the development of photosynthesis (2,700 Ma), CO2 levels in the atmosphere were in the range of 15%. During the period from about 2,700 Ma to about 2,000 Ma, photosynthesis dropped the CO2 concentrations from about 15% to about 8%. By about 2,000 Ma free O2 was beginning to accumulate. This gradual reduction in CO2 levels continued to about 600 Ma at which point CO2 levels were below 1% and O2 levels had risen to more than 15%. 600Ma corresponds to the end of the Precambrian and the beginning of the Cambrian, the end of the cryptozoic and the beginning of the Phanerozic, and the beginning of oxygen-breathing life. Carbon dioxide is an atmospheric gas comprised of one carbon and two oxygen atoms. ...


Precambrian climate

The climate of the late Precambrian was typically cold with glaciation spreading over much of the earth. At this time the continents were bunched up in a supercontinent called Rodinia. Massive deposits of tillites are found and anomalous isotopic signatures are found which are consistent with the idea that the earth at this time was a massive snowball. Mapof Rodinia at the end of the Precambrian after Australia and Antarctica rotated away from the southern hemisphere. Glaciation, often called an ice age, is a geological phenomenon in which massive ice sheets form in the Arctic and Antarctic and advance toward the equator. ... Depiction of Rodinia at time of initial breakup. ... The Snowball Earth hypothesis attempts to explain a number of phenomena noted in the geological record by proposing that an ice age that took place in the Neoproterozoic was so severe that the Earths oceans froze over completely, with only heat from the Earths planetary core causing some...


As the Proterozoic Eon drew to a close, the Earth started to warm up. By the dawn of the Cambrian and the Phanerozoic Eon, Earth was experiencing average global temperatures of about +22 °C. Hundreds of millions of years of ice were replaced with the balmy tropical seas of the Cambrian Period within which life exploded at a rate never seen before or after. (Gould). A degree Celsius (°C) is a unit of temperature named after the Swedish astronomer Anders Celsius (1701-1744), who first proposed a similar system in 1742. ...


Phanerozoic Climate

500 million years of climate change
500 million years of climate change
500 million years of changes in carbon dioxide concentrations
500 million years of changes in carbon dioxide concentrations

Qualitatively, the Earth's climate was varied between conditions that support large-scale continental glaciation and those which are extensively tropical and lack permanent ice caps even at the poles. The time scale for this variation is roughly 140 million years and may be related to Earth's motion into and out of galactic spiral arms (Veizer and Shaviv 2003). The difference in global mean temperatures between a fully glacial earth and ice free Earth is estimated at approximately 10 °C, though far larger changes would be observed at high latitudes and smaller ones at low latitudes. One key requirement for the development of large scale ice sheets is the arrangement of continental land masses at or near the poles. With plate tectonics constantly rearranging the continents, it can also shape long-term climate evolution. However, the presence of land masses at the poles is not sufficient to guarantee glaciations. Evidence exists of past warm periods in Earth's climate when polar land masses similar to Antarctica were home to deciduous forests rather than ice sheets. Description This figure shows the long-term evolution of oxygen isotope ratios during the Phanerozoic eon as measured in fossils, reported by Veizer et al. ... Description This figure shows the long-term evolution of oxygen isotope ratios during the Phanerozoic eon as measured in fossils, reported by Veizer et al. ... Image File history File links Phanerozoic_Carbon_Dioxide. ... Image File history File links Phanerozoic_Carbon_Dioxide. ... Note: This article contains special characters. ... Plate tectonics (from the Greek word for one who constructs and destroys, τεκτων, tekton) is a theory of geology developed to explain the phenomenon of continental drift and is currently the theory accepted by the vast majority of scientists working in this area. ... Deciduous means temporary or tending to fall off (deriving from the Latin word decidere, to fall off). ...


Changes in the atmosphere may also exert an important influence over climate change. The establishment of CO2-consuming (and oxygen-producing) photosythesizing organisms in the Precambrian led to the production of an atmosphere much like today's, though for most of this period it was much higher in CO2 than today. Similarly, the Earth's average temperature was also frequently higher than at present, though it has been argued that over very long time scales climate is largely decoupled from carbon dioxide variations (Veizer et al. 2000). Or more specifically that changing continental configurations and mountain building probably have a larger impact on climate than carbon dioxide. Others dispute this, and suggest that the variations of temperature in response to carbon dioxide changes have been underestimated (Royer et al. 2004). However, it is clear that the preindustrial atmosphere with only 280 ppm CO2 is not far from the lowest ever occurring since the rise of macroscopic life.


Superimposed on the long-term evolution between hot and cold climates have been many short-term fluctuations in climate similar to, and sometimes more severe than, the varying glacial and interglacial states of the present ice age. Some of the most severe fluctuations, such as the Paleocene-Eocene Thermal Maximum, may be related to rapid increases in atmospheric carbon dioxide due to the collapse of natural methane reservoirs in the oceans (see methane clathrates). Severe climate changes also seem to have occurred during the course of the Cretaceous-Tertiary, Permian-Triassic, and Ordovician-Silurian extinction events; however, it is unclear to what degree these changes caused the extinctions rather than merely responding to other processes that may have been more directly responsible for the extinctions. Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years For the animated movie, see Ice Age (movie). ... Climate change during the last 65 million years. ... R-phrases S-phrases , , , Flash point −188 °C Autoignition temperature 537 °C Explosive limits 5–15% Supplementary data page Structure and properties Thermodynamic data Spectral data UV, IR, NMR, MS Related compounds Related alkanes Ethane Propane Related compounds Methanol Chloromethane Except where noted otherwise, data are given for materials in... Burning ice. Methane, released by heating, burns; water drips. ... The Cretaceous-Tertiary (K-T or KT) extinction event, also known as the KT boundary, was a period of massive extinction of species, about 65. ... The Permian-Triassic extinction event, labeled End P here, is the most significant extinction event in this plot for marine fossiliferous genera. ... The two Ordovician-Silurian Extinction events, taken together were the second largest of the major extinction events that have occurred in the Earths history. ...


Quaternary subera

The Quaternary subera includes the current climate. There has been a cycle of ice ages for the past 2.2-2.1 million years (starting before the Quaternary in the late Neogene Period). The Quaternary Period is the geologic time period from the end of the Pliocene Epoch roughly 1. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years For the animated movie, see Ice Age (movie). ... Neogene Period is a unit of geologic time consisting of the Miocene, Pliocene, Pleistocene, and Holocene epochs. ...

Ice core data for the past 400,000 years. Note length of glacial cycles averages ~100,000 years. Blue curve is temperature, green curve is CO2, and red curve is windblown glacial dust (loess). Today's date is on the left side of the graph.
Enlarge
Ice core data for the past 400,000 years. Note length of glacial cycles averages ~100,000 years. Blue curve is temperature, green curve is CO2, and red curve is windblown glacial dust (loess). Today's date is on the left side of the graph.

Note in the graphic on the right the strong 120,000 year periodicity of the cycles, and the striking asymmetry of the curves. This asymmetry is believed to result from complex interactions of feedback mechanisms. It has been observed that ice ages deepen by progressive steps, but the recovery to interglacial conditions occurs in one big step. Graph of Vostok CO2/T/dust from Petit 1999 paper. ... Graph of Vostok CO2/T/dust from Petit 1999 paper. ...


Controlling Factors

Geologically short-term (<120,000 year) temperatures are believed to be driven by orbital factors (see Milankovitch cycles). The arrangements of land masses on the Earth's surface are believed to reinforce these orbital forcing effects. Milankovitch cycles is the name given to the collective effect of changes in the Earths movements upon its climate. ...


Continental drift obviously affects the thermohaline circulation, which transfers heat between the equatorial regions and the poles, as does the extent of polar ice coverage. The thermohaline circulation is a term for the global density-driven circulation of the oceans. ...


The timing of ice ages throughout geologic history is in part controlled by the position of the continental plates on the surface of the Earth. When landmasses are concentrated near the polar regions, there is an increased chance for snow and ice to accumulate. Small changes in solar energy can tip the balance between summers in which the winter snow mass completely melts and summers in which the winter snow persists until the following winter. See the web site Paleomap Project for images of the polar landmass distributions through time. 20 years of solar irradiance data from satellites Solar variations are fluctuations in the amount of energy emitted by the Sun. ...


Comparisons of plate tectonic continent reconstructions and paleoclimatic studies show that the Milankovitch cycles have the greatest effect during geologic eras when landmasses have been concentrated in polar regions, as is the case today. Today, Greenland, Antarctica, and the northern portions of Europe, Asia, and North America are situated such that a minor change in solar energy will tip the balance between year-round snow/ice preservation and complete summer melting. The presence of snow and ice is a well-understood positive feedback mechanism for climate. The Earth today is considered to be prone to ice age glaciations. The tectonic plates of the world were mapped in the second half of the 20th century. ... The table and timeline of geologic periods presented here is in accordance with the dates and nomenclature proposed by the International Commission on Stratigraphy. ... World map showing Europe Europe is conventionally considered one of the seven continents which, in this case, is more a cultural and political distinction than a physiogeographic one. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... World map showing North America A satellite composite image of North America. ... Positive feedback is a type of feedback. ...


Another proposed factor in long term temperature change is the alteration of the carbon cycle balance favoring the production of greenhouse gases and reduction of the geological carbon reservoir. The Uplift-Weathering Hypothesis, first put forward by T. C. Chamberlin in 1899 and later independently proposed in 1988 by Maureen Raymo and colleagues, attributes increased geochemical erosion of limestone and other calcium carbonate geological deposits to increased mountain formation and higher average surface elevation. Others have proposed similar effects due to changes in average water table levels and consequent changes in sub-surface biological activity and PH levels. The carbon cycle is the biogeochemical cycle by which carbon is exchanged between the biosphere, geosphere, hydrosphere and atmosphere of the Earth. ... Top: Increasing atmospheric CO2 levels as measured in the atmosphere and ice cores. ... Limey shale overlaid by limestone. ... Calcium carbonate is a chemical compound, with chemical formula CaCO3. ... The correct title of this article is pH. The initial letter is capitalized due to technical restrictions. ...


Over the very long term the energy output of the sun has gradually increased, on the order of 5% per billion (109) years, and will continue to do so until it reaches the end of its current phase of stellar evolution. For other uses, see Sun (disambiguation). ... In astronomy, stellar evolution is the sequence of changes that a star undergoes during its lifetime, the hundreds of thousands, millions or billions of years during which it emits light and heat. ...


See also

Dendroclimatology is the science of extracting past climate information from information in trees. ...

References

  • Bradley, R.S. (1985). Quaternary paleoclimatology: Methods of paleoclimatic reconstruction. Allen & Unwin.
  • Crowley, T.J., and North, G.R. (1991). Paleoclimatology. Oxford. ISBN 0195105338
  • Gould,Stephen Jay, Wonderful life, the story of the Burgess Shale
  • Imbrie, J., and Imbrie, K.P. (1979). Ice ages: Solving the mystery. Enslow.
  • Lynn Margulis and Dorion Sagan (1990). Origins of Sex : Three Billion Years of Genetic Recombination, Yale University Press, Hartford, Connecticut. ISBN 0300046197.
  • Royer, Dana L., Robert A. Berner, Isabel P. Montañez, Neil J. Tabor, and David J. Beerling (2004). "CO2 as a primary driver of Phanerozoic climate". GSA Today 14 (3): 4–10. DOI:10.1130/1052-5173(2004)014<4:CAAPDO>2.0.CO;2.
  • Shaviv, N. and Veizer, J. (July 2003). "Celestial driver of Phanerozoic climate?". GSA Today: 4-10.
  • Veizer, J., Godderis, Y. and Francois, L.M. (2000). "Evidence for decoupling of atmospheric CO2 and global climate during the Phanerozoic eon". Nature 408: 698–701.

A digital object identifier (or DOI) is a permanent identifier (permalink) given to a World Wide Web file or other Internet document so that if its Internet address changes, users will be redirected to its new address. ...

External links


  Results from FactBites:
 
Paleoclimatology - Wikipedia, the free encyclopedia (1947 words)
Paleoclimatology is the study of climate change taken on the scale of the entire history of the earth.
Glaciers are a widely employed instrument in Paleoclimatology.
The fossil itself is dated with radioactive dating within a wide margin of error.
The Environmental Literacy Council - Paleoclimatology (941 words)
Paleoclimatology is the study of climates in earlier periods in Earth's history.
Paleoclimatology must therefore rely on proxy measures, which are physical phenomena that record evidence of weather.
It also includes brief explanations of the process of climatic cooling, known as glaciation, and a discussion of the theory that long-term climate changes occur in response to Milankovitch Cycles, the cyclical changes in the Earth's relationship to the sun.
  More results at FactBites »

 
 

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