81. Radiocarbon Dating Definition Meaning Information Explanation radiocarbon dating definition, meaning and explanation and more about radiocarbon dating. FreeDefinition - Online Glossary and Encyclopedia, radiocarbon dating. http://www.free-definition.com/Radiocarbon-dating.html

A B C D ... Contact Beta 0.71 powered by: akademie.de PHP PostgreSQL Google News about your search term Radiocarbon dating Radiocarbon dating is the use of a naturally occurring isotope of carbon in radiometric dating to determine the age of organic materials Carbon has two stable isotopes: carbon-12 ( C), and carbon-13 ( C). In addition, there are tiny amounts of the unstable ( radioactive ) isotope carbon-14 C) on earth C has a half-life of just under 6000 years, and so would have long ago vanished from the earth, were it not for its constant formation by cosmic ray impacts on nitrogen in the earth's atmosphere . When cosmic rays enter the atmosphere they undergo various transformations, including the production of neutron s. The resulting neutrons participate in the following reaction: n C + H This reaction is relatively common, as nitrogen constitutes nearly 80% of Earth 's atmosphere. The highest rate of carbon-14 production takes place at altitudes of 30,000-50,000 feet , and at higher geomagnetic lattitudes, but the carbon-14 spreads evenly throughout the atmosphere and reacts with oxygen to form carbon dioxide . Carbon dioxide also permeates the ocean s, dissolving in the water. Since it is assumed that the cosmic ray flux is constant over long periods of time, carbon-14 is assumed to be continuously produced at a constant rate and therefore that the proportion of radioactive to non-radioactive carbon throughout the Earth's atmosphere and oceans is constant.

82. Radiocarbon Dating Of The Angel Site And Phase In Regional Perspective By Sherri Indiana University, Bloomington) radiocarbon dating OF THE ANGEL SITE AND PHASE IN REGIONAL PERSPECTIVE. Fifteen radiocarbon samples http://www.gbl.indiana.edu/abstracts/90/hilgeman_90.html

Sherri L. Hilgeman and Mark R. Schurr (Glenn A. Black Laboratory of Archaeology, Indiana University, Bloomington) RADIOCARBON DATING OF THE ANGEL SITE AND PHASE IN REGIONAL PERSPECTIVE Fifteen radiocarbon samples from the Angel site and an additional ten samples from smaller Angel phase sites have been assayed over a number of years (Figure l). Collectively, they suggest a temporal span for the phase of about 400 years, from AD 1050 to 1450. As a part of our continuing research interests, we have been re-evaluating the extant dates for the Angel site and phase as well as those for Mississippian sites in the Kincaid vicinity in Illinois. The general result of this resurvey is the realization that, typically, one-third to one-half of the radiocarbon assays do not appear to accurately date the archaeological context from which they were recovered. In the case of the Mississippian period occupations of the lower Ohio Valley, this observation means that the radiocarbon dates do not fit well with the temporal ranges established for the ceramic chronology, itself based on valley-wide and regional trends. The initial radiocarbon dates from the Angel site were among the first samples run by the University of Michigan laboratory. The intent was to place the site in time. Three dates (of the six charcoal and mussel shell samples assayed) are generally accepted; that is, they fall within the expected span of a Mississippian period site. Two of these acceptable dates (M-5 and M-7) cannot be evaluated further because the samples were not associated with any artifactual material.

83. Science, Social Sciences, Archaeology, Topics, Geoarchaeology: Radiocarbon Datin Beta Analytic Inc. Professional radiocarbon dating service. Beta Analytic - Commercial radiocarbon dating laboratory in Miami, Florida, US. http://www.combose.com/Science/Social_Sciences/Archaeology/Topics/Geoarchaeology

Top Science Social Sciences Archaeology ... Radiocarbon Dating Related links of interest: Science:Methods and Techniques Science:Earth Sciences:Geology:Geochronology:Radiometric Dating Beta Analytic Inc. - Professional radiocarbon dating service. Beta Analytic - Commercial radiocarbon dating laboratory in Miami, Florida, US. Detailed description of methods and services. CalPal - The Cologne Radiocarbon Calibration and Paleoclimate Research Package is designed to support research on hominid behavioural response to pleistocene climate change. Canadian Archaeological Radiocarbon Database (CARD) - Compilation of radiocarbon measurements that indicate the ages of archaeological and vertebrate palaeontological sites in North America. Carbon Clock Could Show the Wrong Time - From PhysicsWeb, Carbon dating is a mainstay of geology and archaeology, but an enormous peak discovered inthe amount of carbon-14 in the atmosphere between 45 thousand and 11 thousand years ago casts doubt on the biological carbon cycle that underpins the technique. How Stuff Works: Carbon-14 Dating - Introductory tutorial.

84. Roberts Et Al., Optical And Radiocarbon Dating At Jinmium Rock Shelter others. Optical and radiocarbon dating at Jinmium rock shelter in northern Australia. Nature 393. 6683 (May 28, 1998) 358 (5 pages). http://cogweb.ucla.edu/ep/Art/Roberts_98.html

Roberts, Richard; Bird, Michael; Olley, Jon; Galbraith, Rex; and others. Optical and radiocarbon dating at Jinmium rock shelter in northern Australia Nature 393. 6683 (May 28, 1998): 358 (5 pages). Abstract Research shows that quartz sand found with at ancient human dwelling sites in the Jinmium rock shelter, Northern Australia, is 22 thousand years old. Multi-grain optical radiocarbon dating methods demonstrate that the quartz sand consists of relatively young grains dated less than ten thousand years old. Evidence suggests that some grains of sand appear to be older because they were not exposed to sunlight prior to their burial. [Initial thermoluminescent dates had been set at 116,000.] top Home Debate Evolution ... Bibliography Maintained by Francis F. Steen , Communication Studies, University of California Los Angeles

85. Informationsphere.com: Radiocarbon Dating radiocarbon dating SendTo Print More Category Science Editor s Choice 195 views Texts Images Related Terms Related Web Sites http://www.informationsphere.com/html/1456.htm

@import url(http://www.informationsphere.com/styles/style.css); Home Contributors Site Info Newsletter ... Contact Browse by Alphabet Letter A Letter B Letter C Letter D Letter E Letter F Letter G Letter H Letter I Letter J Letter K Letter L Letter M Letter N Letter O Letter P Letter Q Letter R Letter S Letter T Letter U Letter V Letter W Letter X Letter Y Letter Z Numbers Browse by Category Anthropology Arts Astronomy Biology Chemistry Entertainment Environment Geology History Mathematics Meteorology Military Miscellaneous Physics Politics Regional Science (General) Social Science Home Categories Alphabet Quickfinder Random Terms Top Terms FREE Newsletter About Contact 2762 Subscribers can't be wrong: Get your FREE copy today and join now! click here... Sexual Intercour... Male Orgasm Orgasm Lunitidal Interv... Air-Condition Chemical Weather... Barrel Of Oil Eq... Law Of Conservat... Desert Climate Law Of Supply An... Thailand : According to WHO bird flu may have passed between humans Search the Web! Radiocarbon Dating Send-To Print More Category: Science Editor's Choice 202 views Texts Images Related Terms Related Web Sites Available Texts Southern Mehodist University, Dept. Anthropology

86. Radiocarbon Dating next up previous Next The Differential Equation y = Up Differential Equations Previous Malthusian (unlimited) growth radiocarbon dating. http://www.math.jhu.edu/courses/107/archives/notes/f01coursenotes/node6.html

Next: The Differential Equation y'= Up: Differential Equations Previous: Malthusian (unlimited) growth Radiocarbon Dating The technique of radiocarbon dating, discovered by the American chemist A. F. Libby in 1947, uses the law of radioactive decay to determine the age of once living organisms. The idea is based on the fact that that there are two forms of carbon, C (most common) and a radioactive isotope C formed high in the atmosphere. Moreover, the ratio of C to C has been fairly constant over a long period (roughly 50,000 years) of time. Both forms of carbon are absorbed by living tissue in the same ratio as in the atmosphere. When the tissue dies, carbon is no longer absorbed and the radioactive decay of C causes the ratio of C to C to decline over time. The half-life of C (that is the time required for a sample to decay to half its original amount) is known to be 5730 years. Therefore to date some material, a small sample is burned to form C O and the C content is then measured. Since the amount of C in living tissue is known, the age of the material can be determined.

87. Radiocarbon Dating - Wikipedia radiocarbon dating. radiocarbon dating is the use of a naturally occurring isotope of carbon to determine the age of organic materials. http://www.phatnav.com/wiki/wiki.phtml?title=Radiocarbon_dating

88. Radiocarbon Dating radiocarbon dating is a scientific method of dating which can be used on any material which came from a living source within the last 40,000 years. http://www.creswell-crags.org.uk/virtuallytheiceage/Discover the past/Nick/Radio

Home Discover the past Excavation in the late 20th century : Radiocarbon dating Radiocarbon dating is a scientific method of dating which can be used on any material which came from a living source within the last 40,000 years. Such organic materials include things often found by archaeologistgists such as bone, antler, ivory, teeth and charcoal. What is radiocarbon ? Radiocarbon or carbon-14 (C14) is a radioactive isotope of carbon. It is produced in the upper atmosphere by radiation from the sun. It is absorbed by plants with carbon dioxide from the air. Animals eat the plants and, in turn, absorb C14 from them. How is radiocarbon useful for dating ? When plants and animals die they stop taking in C14 and, the C14 they have absorbed begins radioactive decay. After 5730 years only half of it will be left. This decreases to 25% after 11,460 years, 12.5% after 17,190 years, 6.25% after 22,290 years and so on. After 37,000 years less than 1% of the original radiocarbon will remain. Eventually, in about 70,000 years, it will all be gone. Given this known rate of decay, it is possible to calculate the age of an organic material by measuring the amount of radiocarbon remaining in a sample from it.

89. FSTS Doing Archaeology In Minnesota - Radiocarbon Dating radiocarbon dating. Since then measurement of radiocarbon has been used extensively in archaeology, especially in the dating of human and animal bones. http://www.fromsitetostory.org/sources/archinmn/archinmndating.asp

Doing Archaeology in Minnesota Radiocarbon Dating Contents Stories Sources Search ... Home The possibility of dating organic material by measuring its loss of the radiocarbon (C-14) atoms that were present when the organism was alive was first suggested in the 1940s. Since then measurement of radiocarbon has been used extensively in archaeology, especially in the dating of human and animal bones. Although it has been a tool of enormous value to archaeologists in the past 50 years, it has been limited by several factors. In most cases it requires a fairly large sample of material; samples can be easily contaminated in the process of handling; it yields a relatively wide range of possible dates; and its effective use is limited to the furthest age of 40,000 or 50,000 years. Improvements and refinements of the technique have been made over the years, and since the mid-1980s there has been a significant advance in developing a process for high-precision radiocarbon dating using accelerated mass spectrometry (AMS). This can be used to analyze very small samples, extends the range of possible dating to nearly 100,000 years, and yields more precise dates. Its chief drawback is cost. Meanwhile, thermoluminescence, a technique for dating pottery or any material that has been baked or fired at a high temperature, offers still more possibility for accurate dating of archaeological sites and the ancient cultures that created them.

90. Radiocarbon Dating - InformationBlast radiocarbon dating Information Blast. radiocarbon dating. The accuracy of radiocarbon dating is lower for samples originating from such plateau periods. http://www.informationblast.com/Radiocarbon_dating.html

Radiocarbon dating Radiocarbon dating is the use of a naturally occurring isotope of carbon in radiometric dating to determine the age of organic materials Carbon has two stable isotopes: carbon-12 ( C), and carbon-13 ( C). In addition, there are tiny amounts of the unstable ( radioactive ) isotope carbon-14 C) on earth C has a half-life of just under 6000 years, and so would have long ago vanished from the earth, were it not for its constant formation by cosmic ray impacts on nitrogen in the earth's atmosphere . When cosmic rays enter the atmosphere they undergo various transformations, including the production of neutrons . The resulting neutrons participate in the following reaction: n C + H This reaction is relatively common, as nitrogen constitutes nearly 80% of Earth 's atmosphere. The highest rate of carbon-14 production takes place at altitudes of 30,000-50,000 feet , and at higher geomagnetic lattitudes, but the carbon-14 spreads evenly throughout the atmosphere and reacts with oxygen to form carbon dioxide . Carbon dioxide also permeates the oceans , dissolving in the water. Since it is assumed that the cosmic ray flux is constant over long periods of time, carbon-14 is assumed to be continuously produced at a constant rate and therefore that the proportion of radioactive to non-radioactive carbon throughout the Earth's atmosphere and oceans is constant.

91. How Good Are Those Young-Earth Arguments: Radiocarbon Dating Treering dating (see Topic 27) gives us a wonderful check on the radiocarbon dating method for the last 8000 years. That is, we http://www.talkorigins.org/faqs/hovind/howgood-c14.html

How Good Are Those Young-Earth Arguments? A Close Look at Dr. Hovind's List of Young-Earth Arguments and Other Claims by Dave E. Matson Previous Contents Next The following material has been taken from a sheet entitled Several Faulty Assumptions Are Used in all Radiometric Dating Methods. Carbon 14 is used for this example:, which was put out by Dr. Hovind. Dr. Hovind (R1): The atmospheric C-14 is presently only 1/3 of the way to an equilibrium value which will be reached in 30,000 years. This nullifies the carbon-14 method as well as demonstrating that the earth is less than 10,000 years old. The above is offered as a simple fact of research. Knowing how faulty creationist "facts" can be, let's do a little research of our own. One suspects that the scientific world would not be using the carbon-14 method if it were so obviously flawed. Could it be that the whole scientific community has missed this point, or is it another case of creationist daydreaming? This argument was popularized by Henry Morris ( , p.164), who used some calculations done in 1968 by Melvin Cook to get the 10,000-year figure. In 1968 another creationist, Robert L. Whitelaw, using a greater ratio of carbon-14 production to decay, concluded that only 5000 years passed since carbon-14 started forming in the atmosphere!

92. Lukol Directory - Science Social Sciences Archaeology Topics Geoarchaeology Radi WebInfo Extensive information concerning the radiocarbon dating method from Tom Higham, Radiocarbon Laboratory, University of Waikato, New Zealand. http://www.lukol.com/Top/Science/Social_Sciences/Archaeology/Topics/Geoarchaeolo

Lukol Directory - Science Social Sciences Archaeology ... Radiocarbon Web-Info Extensive information concerning the radiocarbon dating method from Tom Higham, Radiocarbon Laboratory, University of Waikato, New Zealand. http://www.c14dating.com/ RadioCarbon International journal of radio-isotope dating: Article indexes; sales of subscriptions and back issues. http://www.radiocarbon.org/ Rafter Radiocarbon Laboratory At the Institute of Geological and Nuclear Sciences, New Zealand, provides radiocarbon dating services to international scientific, academic, and art/antiquities clients. http://www.RafterRadiocarbon.co.nz Canadian Archaeological Radiocarbon Database (CARD) Compilation of radiocarbon measurements that indicate the ages of archaeological and vertebrate palaeontological sites in North America. http://www.canadianarchaeology.com/radiocarbon/... Beta Analytic Commercial radiocarbon dating laboratory in Miami, Florida, US. Detailed description of methods and services. http://www.radiocarbon.com/ Beta Analytic Inc.

93. Forest:How Do We Know?:Radiocarbon Dating This section will describe two methods that scientists use today to date objects and events relative dating and radiocarbon dating. http://www.museum.state.il.us/muslink/forest/htmls/how_rcarbon.html

This section will describe two methods that scientists use today to date objects and events: relative dating and radiocarbon dating. Relative Dating Prior to the availability of radiocarbon dates (and when there is no material suitable for a radiocarbon date) scientists used a system of relative dating. Relative dating establishes the sequence of physical or cultural events in time. Knowing which events came before or after others allows scientists to analyze the relationships between the events. For example, archaeologists might date materials based upon relative depth of burial in a site. The archaeologists record and analyze the changes in types and styles of human-made items from different levels according to the principle explained below. General principle Archaeologists, geologists, and other scientists make use of this principle when dating sediments or layers relative to one another: The principle of superposition states that in an undisturbed sequence of sediments, layers increase in age from top to bottom. Drawbacks of relative dating methods Relative methods do not always reflect the true sequence of events in time. There are potential problems with relative dating.

94. RADIOCARBON DATING - Meaning And Definition Of The Word Dictionary, Medical Dictionary. Search Dictionary radiocarbon dating Dictionary Entry and Meaning. WordNet Dictionary. Definition n a http://www.hyperdictionary.com/dictionary/radiocarbon dating

English Dictionary Computer Dictionary Thesaurus Dream Dictionary ... Medical Dictionary Search Dictionary: RADIOCARBON DATING: Dictionary Entry and Meaning WordNet Dictionary Definition: [n] a chemical analysis used ... years Synonyms: carbon dating carbon-14 dating See Also: dating Glossary Definition: an absolute dating method based on the radioactive decay of Carbon-14 contained in organic materials. HOME ABOUT HYPERDICTIONARY

95. Nabo: Dating radiocarbon dating. Reports and discussion documents on radiocarbon dating are available from here. Further reports will added in http://www.geo.ed.ac.uk/nabo/c14_nabo.html

NABO: Dating Home Page Introduction NABO News Newsletters ... Field Research Dating Publications Search WEBBONE NABONE Radiocarbon Dating Reports and discussion documents on radiocarbon dating are available from here. Further reports will added in time and it is hoped that this seciton will become a useful information source for a wide range of researchers. Radiocarbon reports Update on Analysis of Materials from Akurvik, Strandir, NW Iceland

96. American Scientist Online - Fifty Years Of Radiocarbon Dating Fifty Years of radiocarbon dating. But a few of the key archaeological findings from radiocarbon dating are noted. Go to Article. http://www.americanscientist.org/template/AssetDetail/assetid/14715

Home Current Issue Archives Bookshelf ... Subscribe In This Section Search Book Reviews by Issue Issue Index Topical Index ... Classics Site Search Advanced Search Visitor Login Username Password Help with login Forgot your password? Change your username see full issue: January-February 2000 Volume: Number: Page: DOI: Fifty Years of Radiocarbon Dating This widely applied technique has made major strides since its introduction a half-century ago at the University of Chicago R. E. Taylor Since its introduction a half-century ago at the University of Chicago, radiocarbon dating has proven invaluable to investigators working in many different disciplines. R. E. Taylor, an archaeologist, describes the origins of this technique and the progress that has ensued, including advances that have made it possible to calibrate radiocarbon ages precisely and to date a sample that contains only milligrams of carbon. Because many tens of thousands of radiocarbon measurements have been conducted over the years, a comprehensive summary of results is impossible. But a few of the key archaeological findings from radiocarbon dating are noted. Go to Article ADVERTISEMENTS About American Scientist Site Map Text Archive ... Contact Us

97. NS&T : Industry : Radiocarbon Dating Industry radiocarbon dating. Archeologists determine dates of samples, that were once alive (eg in bone, charcoal, leather) by http://www.aboutnuclear.org/view.cgi?fC=Industry,Radiocarbon_Dating

98. Radiocarbon Dating Of Delta Materials Deltas, radiocarbon dating, and measurements of sediment storage and subsidence In Holocene marine deltaic sequences there is no simple relationship between http://www.nmnh.si.edu/paleo/deltas/radiocarbon.htm

The Deltas-Global Change Program (DCP) Modern deltas Geoarchaeology Anthropogenic influences Radiocarbon dating Research opportunities Stanley CV Papers Home Deltas, radiocarbon dating, and measurements of sediment storage and subsidence In Holocene marine deltaic sequences there is no simple relationship between radiocarbon age and depth of sampling. The Nile and Ganges-Brahmaputra deltas show remarkably similar radiocarbon age-depth relationships: (1) most radiocarbon dates, by conventional and accelorator mass spectrometric (AMS) analyses, are older (some by 4000 yr) than reasonably expected; (2) dates are commonly inverted (i.e., older upcore); and (3) sample dates at delta surfaces commonly exceed 2000 yr B.P. These anomalous age-depth phenomena are in part a response to reservoir effects, introduction of old carbon, and, emphasized herein, influence of sediment storage and remobilization that prevail in fluvial and delta plains. In fluvial systems, sediment generally is not transported in a single episode from its original source area to the sea. Rather, material transported from upland reaches and river valley to coast is subject to a repeated series of depositional, burial, and erosional events induced by episodic flooding, overbank sedimentation, and channel migration. Because sediment is likely to be temporarily stored in the delta plain, it is difficult to determine the time of a sediment's final deposition and burial at a delta site. A successful strategy requires use of several independent dating methods, including

99. Using Radiocarbon Dating To Establish The Age Of Iron-Based Artifacts Feature Archaeotechnology. Using radiocarbon dating to Establish the Age of IronBased Artifacts. radiocarbon dating IRON-BASED MATERIALS. http://www.tms.org/pubs/journals/JOM/0305/Cook-0305.html

TMS ONLINE TMS PUBLICATIONS SITE MAP An Article from the May 2003 JOM : A Hypertext-Enhanced Article Andrea C. Cook is a teacher at High Tech High in San Diego, California. John R. Southon is with the University of California at Irvine . Jeffrey Wadsworth is with Battelle Memorial Institute in Columbus, Ohio. Exploring traditional, innovative, and revolutionary issues in the minerals, metals, and materials fields. OUR LATEST ISSUE READ JOM ON-LINE ... COVER GALLERY JOM MENU JOM HOME PAGE MEMBER-ONLY ACCESS TABLES OF CONTENTS ... LETTER TO EDITOR Feature: Archaeotechnology Using Radiocarbon Dating to Establish the Age of Iron-Based Artifacts Andrea C. Cook, John R. Southon, and Jeffrey Wadsworth Dawn Ueda and Tom Brown next to the accelerator mass spectrometer at Lawrence Livermore Laboratory . (Photo courtesy of the Center for Accelerator Mass Spectrometry at Lawrence Livermore National Laboratory Over the last 40 years, there has been a discernible increase in the number of scholars who have focused their research on early industrial organizations, a field of study that has come to be known as Archaeotechnology. Archaeologists have conducted fieldwork geared to the study of ancient technologies in a cultural context and have drawn on the laboratory analyses developed by materials scientists as one portion of their interpretive program. Papers for this department are solicited and/or reviewed by Michael Notis, a professor and director of the

100. Radiocarbon Dating. The American Heritage® Dictionary Of The English Language: radiocarbon dating. The American Heritage® Dictionary of the English Language Fourth Edition. 2000. 2000. radiocarbon dating. NOUN http://www.bartleby.com/61/42/R0014200.html

Select Search All Bartleby.com All Reference Columbia Encyclopedia World History Encyclopedia Cultural Literacy World Factbook Columbia Gazetteer American Heritage Coll. Dictionary Roget's Thesauri Roget's II: Thesaurus Roget's Int'l Thesaurus Quotations Bartlett's Quotations Columbia Quotations Simpson's Quotations Respectfully Quoted English Usage Modern Usage American English Fowler's King's English Strunk's Style Mencken's Language Cambridge History The King James Bible Oxford Shakespeare Gray's Anatomy Farmer's Cookbook Post's Etiquette Bulfinch's Mythology Frazer's Golden Bough All Verse Anthologies Dickinson, E. Eliot, T.S. Frost, R. Hopkins, G.M. Keats, J. Lawrence, D.H. Masters, E.L. Sandburg, C. Sassoon, S. Whitman, W. Wordsworth, W. Yeats, W.B. All Nonfiction Harvard Classics American Essays Einstein's Relativity Grant, U.S. Roosevelt, T. Wells's History Presidential Inaugurals All Fiction Shelf of Fiction Ghost Stories Short Stories Shaw, G.B. Stein, G. Stevenson, R.L. Wells, H.G. Reference American Heritage Dictionary radiocarbon ... BIBLIOGRAPHIC RECORD The American Heritage Dictionary of the English Language: Fourth Edition.

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

Page 5     81-100 of 115    Back | 1  | 2  | 3  | 4  | 5  | 6  | Next 20