https://en.wikipedia.org/w/index.php?action=history&feed=atom&title=First_appearance_datumFirst appearance datum - Revision history2025-06-12T00:57:43ZRevision history for this page on the wikiMediaWiki 1.45.0-wmf.4https://en.wikipedia.org/w/index.php?title=First_appearance_datum&diff=1215645521&oldid=prevXiphactinus88: Templates2024-03-26T10:23:06Z<p>Templates</p>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>{{Short description|Term to designate the first appearance of a species in the geologic record}}</div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>{{Short description|Term to designate the first appearance of a species in the geologic record}}</div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref name=":0">{{Cite journal|last1=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=Bowring|first4=Samuel A.|date=August 2013|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web |title=Last-appearance datum |url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526 |url-status=live |archive-url=https://web.archive.org/web/20210422144821/https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526 |archive-date=2021-04-22 |access-date=<del style="font-weight: bold; text-decoration: none;">2021</del>-<del style="font-weight: bold; text-decoration: none;">04</del>-<del style="font-weight: bold; text-decoration: none;">22</del> |website=Oxford Reference |language=en}}</ref> </div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref name=":0">{{Cite journal|last1=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=Bowring|first4=Samuel A.|date=August 2013|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web |title=Last-appearance datum |url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526 |url-status=live |archive-url=https://web.archive.org/web/20210422144821/https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526 |archive-date=2021-04-22 |access-date=<ins style="font-weight: bold; text-decoration: none;">2024</ins>-<ins style="font-weight: bold; text-decoration: none;">03</ins>-<ins style="font-weight: bold; text-decoration: none;">26</ins> |website=Oxford Reference |language=en}}</ref> </div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>FADs are frequently used to designate segments in the [[geologic time scale]]. A given FAD can be used to define a [[Global Boundary Stratotype Section and Point]] (GSSP).<ref name=":0" /> For example, the beginning of the [[Tremadocian]] Stage of the [[Ordovician]] Period is marked by the first appearance of the [[conodont]] ''Iapetognathus fluctivagus'' in the geologic record. This occurs in [[Stratigraphy|bed]] 23 of the rock formation known as the Green Point section, located in western [[Newfoundland (island)|Newfoundland]], as well as in geologically correlated [[Stratum|strata]] in many parts of the world.<ref>{{Cite web|title=International Commission on Stratigraphy|url=https://stratigraphy.org/gssps/|access-date=<del style="font-weight: bold; text-decoration: none;">2021</del>-<del style="font-weight: bold; text-decoration: none;">04</del>-<del style="font-weight: bold; text-decoration: none;">05</del>|website=stratigraphy.org}}</ref> However, [[Diachronism|diachronous]] FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances.<ref name=":0" /><ref>{{Cite journal|last1=Servais|first1=Thomas|last2=Molyneux|first2=Stewart G.|last3=Li|first3=Jun|last4=Nowak|first4=Hendrik|last5=Rubinstein|first5=Claudia V.|last6=Vecoli|first6=Marco|last7=Wang|first7=Wen Hui|last8=Yan|first8=Kui|date=2018|title=First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12248|journal=Lethaia|language=en|volume=51|issue=2|pages=248|doi=10.1111/let.12248|issn=1502-3931|hdl=20.500.12210/34398|hdl-access=free}}</ref> Use of other data, such as [[Radiometric dating|radiometric data]], may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units.<ref>{{Cite journal|last1=Pasquo|first1=Mercedes di|last2=Grader|first2=George W.|last3=Isaacson|first3=Peter|last4=Souza|first4=Paulo A.|last5=Iannuzzi|first5=Roberto|last6=Díaz-Martínez|first6=Enrique|date=2015-10-03|title=Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia|url=https://doi.org/10.1080/08912963.2014.910204|journal=Historical Biology|volume=27|issue=7|pages=891|doi=10.1080/08912963.2014.910204|issn=0891-2963|s2cid=129872538|hdl=11336/80106|hdl-access=free}}</ref></div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>FADs are frequently used to designate segments in the [[geologic time scale]]. A given FAD can be used to define a [[Global Boundary Stratotype Section and Point]] (GSSP).<ref name=":0" /> For example, the beginning of the [[Tremadocian]] Stage of the [[Ordovician]] Period is marked by the first appearance of the [[conodont]] ''Iapetognathus fluctivagus'' in the geologic record. This occurs in [[Stratigraphy|bed]] 23 of the rock formation known as the Green Point section, located in western [[Newfoundland (island)|Newfoundland]], as well as in geologically correlated [[Stratum|strata]] in many parts of the world.<ref>{{Cite web|title=International Commission on Stratigraphy|url=https://stratigraphy.org/gssps/|access-date=<ins style="font-weight: bold; text-decoration: none;">2024</ins>-<ins style="font-weight: bold; text-decoration: none;">03</ins>-<ins style="font-weight: bold; text-decoration: none;">26</ins>|website=stratigraphy.org}}</ref> However, [[Diachronism|diachronous]] FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances.<ref name=":0" /><ref>{{Cite journal|last1=Servais|first1=Thomas|last2=Molyneux|first2=Stewart G.|last3=Li|first3=Jun|last4=Nowak|first4=Hendrik|last5=Rubinstein|first5=Claudia V.|last6=Vecoli|first6=Marco|last7=Wang|first7=Wen Hui|last8=Yan|first8=Kui|date=2018|title=First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12248|journal=Lethaia|language=en|volume=51|issue=2|pages=248|doi=10.1111/let.12248|issn=1502-3931|hdl=20.500.12210/34398|hdl-access=free}}</ref> Use of other data, such as [[Radiometric dating|radiometric data]], may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units.<ref>{{Cite journal|last1=Pasquo|first1=Mercedes di|last2=Grader|first2=George W.|last3=Isaacson|first3=Peter|last4=Souza|first4=Paulo A.|last5=Iannuzzi|first5=Roberto|last6=Díaz-Martínez|first6=Enrique|date=2015-10-03|title=Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia|url=https://doi.org/10.1080/08912963.2014.910204|journal=Historical Biology|volume=27|issue=7|pages=891|doi=10.1080/08912963.2014.910204|issn=0891-2963|s2cid=129872538|hdl=11336/80106|hdl-access=free}}</ref></div></td>
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</table>Xiphactinus88https://en.wikipedia.org/w/index.php?title=First_appearance_datum&diff=1197859906&oldid=prevOAbot: Open access bot: hdl updated in citation with #oabot.2024-01-22T05:34:57Z<p><a href="/wiki/Wikipedia:OABOT" class="mw-redirect" title="Wikipedia:OABOT">Open access bot</a>: hdl updated in citation with #oabot.</p>
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Previous revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 05:34, 22 January 2024</td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref name=":0">{{Cite journal|last1=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=Bowring|first4=Samuel A.|date=August 2013|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web |title=Last-appearance datum |url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526 |url-status=live |archive-url=https://web.archive.org/web/20210422144821/https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526 |archive-date=2021-04-22 |access-date=2021-04-22 |website=Oxford Reference |language=en}}</ref> </div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref name=":0">{{Cite journal|last1=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=Bowring|first4=Samuel A.|date=August 2013|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web |title=Last-appearance datum |url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526 |url-status=live |archive-url=https://web.archive.org/web/20210422144821/https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526 |archive-date=2021-04-22 |access-date=2021-04-22 |website=Oxford Reference |language=en}}</ref> </div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>FADs are frequently used to designate segments in the [[geologic time scale]]. A given FAD can be used to define a [[Global Boundary Stratotype Section and Point]] (GSSP).<ref name=":0" /> For example, the beginning of the [[Tremadocian]] Stage of the [[Ordovician]] Period is marked by the first appearance of the [[conodont]] ''Iapetognathus fluctivagus'' in the geologic record. This occurs in [[Stratigraphy|bed]] 23 of the rock formation known as the Green Point section, located in western [[Newfoundland (island)|Newfoundland]], as well as in geologically correlated [[Stratum|strata]] in many parts of the world.<ref>{{Cite web|title=International Commission on Stratigraphy|url=https://stratigraphy.org/gssps/|access-date=2021-04-05|website=stratigraphy.org}}</ref> However, [[Diachronism|diachronous]] FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances.<ref name=":0" /><ref>{{Cite journal|last1=Servais|first1=Thomas|last2=Molyneux|first2=Stewart G.|last3=Li|first3=Jun|last4=Nowak|first4=Hendrik|last5=Rubinstein|first5=Claudia V.|last6=Vecoli|first6=Marco|last7=Wang|first7=Wen Hui|last8=Yan|first8=Kui|date=2018|title=First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12248|journal=Lethaia|language=en|volume=51|issue=2|pages=248|doi=10.1111/let.12248|issn=1502-3931}}</ref> Use of other data, such as [[Radiometric dating|radiometric data]], may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units.<ref>{{Cite journal|last1=Pasquo|first1=Mercedes di|last2=Grader|first2=George W.|last3=Isaacson|first3=Peter|last4=Souza|first4=Paulo A.|last5=Iannuzzi|first5=Roberto|last6=Díaz-Martínez|first6=Enrique|date=2015-10-03|title=Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia|url=https://doi.org/10.1080/08912963.2014.910204|journal=Historical Biology|volume=27|issue=7|pages=891|doi=10.1080/08912963.2014.910204|issn=0891-2963|s2cid=129872538|hdl=11336/80106|hdl-access=free}}</ref></div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>FADs are frequently used to designate segments in the [[geologic time scale]]. A given FAD can be used to define a [[Global Boundary Stratotype Section and Point]] (GSSP).<ref name=":0" /> For example, the beginning of the [[Tremadocian]] Stage of the [[Ordovician]] Period is marked by the first appearance of the [[conodont]] ''Iapetognathus fluctivagus'' in the geologic record. This occurs in [[Stratigraphy|bed]] 23 of the rock formation known as the Green Point section, located in western [[Newfoundland (island)|Newfoundland]], as well as in geologically correlated [[Stratum|strata]] in many parts of the world.<ref>{{Cite web|title=International Commission on Stratigraphy|url=https://stratigraphy.org/gssps/|access-date=2021-04-05|website=stratigraphy.org}}</ref> However, [[Diachronism|diachronous]] FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances.<ref name=":0" /><ref>{{Cite journal|last1=Servais|first1=Thomas|last2=Molyneux|first2=Stewart G.|last3=Li|first3=Jun|last4=Nowak|first4=Hendrik|last5=Rubinstein|first5=Claudia V.|last6=Vecoli|first6=Marco|last7=Wang|first7=Wen Hui|last8=Yan|first8=Kui|date=2018|title=First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12248|journal=Lethaia|language=en|volume=51|issue=2|pages=248|doi=10.1111/let.12248|issn=1502-3931<ins style="font-weight: bold; text-decoration: none;">|hdl=20.500.12210/34398|hdl-access=free</ins>}}</ref> Use of other data, such as [[Radiometric dating|radiometric data]], may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units.<ref>{{Cite journal|last1=Pasquo|first1=Mercedes di|last2=Grader|first2=George W.|last3=Isaacson|first3=Peter|last4=Souza|first4=Paulo A.|last5=Iannuzzi|first5=Roberto|last6=Díaz-Martínez|first6=Enrique|date=2015-10-03|title=Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia|url=https://doi.org/10.1080/08912963.2014.910204|journal=Historical Biology|volume=27|issue=7|pages=891|doi=10.1080/08912963.2014.910204|issn=0891-2963|s2cid=129872538|hdl=11336/80106|hdl-access=free}}</ref></div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==See also ==</div></td>
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</table>OAbothttps://en.wikipedia.org/w/index.php?title=First_appearance_datum&diff=1171934361&oldid=prevOAbot: Open access bot: hdl updated in citation with #oabot.2023-08-24T01:11:33Z<p><a href="/wiki/Wikipedia:OABOT" class="mw-redirect" title="Wikipedia:OABOT">Open access bot</a>: hdl updated in citation with #oabot.</p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Previous revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 01:11, 24 August 2023</td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref name=":0">{{Cite journal|last1=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=Bowring|first4=Samuel A.|date=August 2013|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web |title=Last-appearance datum |url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526 |url-status=live |archive-url=https://web.archive.org/web/20210422144821/https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526 |archive-date=2021-04-22 |access-date=2021-04-22 |website=Oxford Reference |language=en}}</ref> </div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref name=":0">{{Cite journal|last1=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=Bowring|first4=Samuel A.|date=August 2013|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web |title=Last-appearance datum |url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526 |url-status=live |archive-url=https://web.archive.org/web/20210422144821/https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526 |archive-date=2021-04-22 |access-date=2021-04-22 |website=Oxford Reference |language=en}}</ref> </div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>FADs are frequently used to designate segments in the [[geologic time scale]]. A given FAD can be used to define a [[Global Boundary Stratotype Section and Point]] (GSSP).<ref name=":0" /> For example, the beginning of the [[Tremadocian]] Stage of the [[Ordovician]] Period is marked by the first appearance of the [[conodont]] ''Iapetognathus fluctivagus'' in the geologic record. This occurs in [[Stratigraphy|bed]] 23 of the rock formation known as the Green Point section, located in western [[Newfoundland (island)|Newfoundland]], as well as in geologically correlated [[Stratum|strata]] in many parts of the world.<ref>{{Cite web|title=International Commission on Stratigraphy|url=https://stratigraphy.org/gssps/|access-date=2021-04-05|website=stratigraphy.org}}</ref> However, [[Diachronism|diachronous]] FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances.<ref name=":0" /><ref>{{Cite journal|last1=Servais|first1=Thomas|last2=Molyneux|first2=Stewart G.|last3=Li|first3=Jun|last4=Nowak|first4=Hendrik|last5=Rubinstein|first5=Claudia V.|last6=Vecoli|first6=Marco|last7=Wang|first7=Wen Hui|last8=Yan|first8=Kui|date=2018|title=First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12248|journal=Lethaia|language=en|volume=51|issue=2|pages=248|doi=10.1111/let.12248|issn=1502-3931}}</ref> Use of other data, such as [[Radiometric dating|radiometric data]], may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units.<ref>{{Cite journal|last1=Pasquo|first1=Mercedes di|last2=Grader|first2=George W.|last3=Isaacson|first3=Peter|last4=Souza|first4=Paulo A.|last5=Iannuzzi|first5=Roberto|last6=Díaz-Martínez|first6=Enrique|date=2015-10-03|title=Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia|url=https://doi.org/10.1080/08912963.2014.910204|journal=Historical Biology|volume=27|issue=7|pages=891|doi=10.1080/08912963.2014.910204|issn=0891-2963|s2cid=129872538}}</ref></div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>FADs are frequently used to designate segments in the [[geologic time scale]]. A given FAD can be used to define a [[Global Boundary Stratotype Section and Point]] (GSSP).<ref name=":0" /> For example, the beginning of the [[Tremadocian]] Stage of the [[Ordovician]] Period is marked by the first appearance of the [[conodont]] ''Iapetognathus fluctivagus'' in the geologic record. This occurs in [[Stratigraphy|bed]] 23 of the rock formation known as the Green Point section, located in western [[Newfoundland (island)|Newfoundland]], as well as in geologically correlated [[Stratum|strata]] in many parts of the world.<ref>{{Cite web|title=International Commission on Stratigraphy|url=https://stratigraphy.org/gssps/|access-date=2021-04-05|website=stratigraphy.org}}</ref> However, [[Diachronism|diachronous]] FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances.<ref name=":0" /><ref>{{Cite journal|last1=Servais|first1=Thomas|last2=Molyneux|first2=Stewart G.|last3=Li|first3=Jun|last4=Nowak|first4=Hendrik|last5=Rubinstein|first5=Claudia V.|last6=Vecoli|first6=Marco|last7=Wang|first7=Wen Hui|last8=Yan|first8=Kui|date=2018|title=First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12248|journal=Lethaia|language=en|volume=51|issue=2|pages=248|doi=10.1111/let.12248|issn=1502-3931}}</ref> Use of other data, such as [[Radiometric dating|radiometric data]], may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units.<ref>{{Cite journal|last1=Pasquo|first1=Mercedes di|last2=Grader|first2=George W.|last3=Isaacson|first3=Peter|last4=Souza|first4=Paulo A.|last5=Iannuzzi|first5=Roberto|last6=Díaz-Martínez|first6=Enrique|date=2015-10-03|title=Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia|url=https://doi.org/10.1080/08912963.2014.910204|journal=Historical Biology|volume=27|issue=7|pages=891|doi=10.1080/08912963.2014.910204|issn=0891-2963|s2cid=129872538<ins style="font-weight: bold; text-decoration: none;">|hdl=11336/80106|hdl-access=free</ins>}}</ref></div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==See also ==</div></td>
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</table>OAbothttps://en.wikipedia.org/w/index.php?title=First_appearance_datum&diff=1169898158&oldid=prevHeyElliott: Added archive2023-08-12T00:38:07Z<p>Added archive</p>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>{{Short description|Term to designate the first appearance of a species in the geologic record}}</div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref name=":0">{{Cite journal|last1=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=Bowring|first4=Samuel A.|date=August 2013|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web|title=Last-appearance datum|url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526|url-status=live|access-date=2021-04-22|website=Oxford Reference|language=en}}</ref> </div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref name=":0">{{Cite journal|last1=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=Bowring|first4=Samuel A.|date=August 2013|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web<ins style="font-weight: bold; text-decoration: none;"> </ins>|title=Last-appearance datum<ins style="font-weight: bold; text-decoration: none;"> </ins>|url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526<ins style="font-weight: bold; text-decoration: none;"> </ins>|url-status=live<ins style="font-weight: bold; text-decoration: none;"> |archive-url=https://web.archive.org/web/20210422144821/https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526 |archive-date=2021-04-22 </ins>|access-date=2021-04-22<ins style="font-weight: bold; text-decoration: none;"> </ins>|website=Oxford Reference<ins style="font-weight: bold; text-decoration: none;"> </ins>|language=en}}</ref> </div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>FADs are frequently used to designate segments in the [[geologic time scale]]. A given FAD can be used to define a [[Global Boundary Stratotype Section and Point]] (GSSP).<ref name=":0" /> For example, the beginning of the [[Tremadocian]] Stage of the [[Ordovician]] Period is marked by the first appearance of the [[conodont]] ''Iapetognathus fluctivagus'' in the geologic record. This occurs in [[Stratigraphy|bed]] 23 of the rock formation known as the Green Point section, located in western [[Newfoundland (island)|Newfoundland]], as well as in geologically correlated [[Stratum|strata]] in many parts of the world.<ref>{{Cite web|title=International Commission on Stratigraphy|url=https://stratigraphy.org/gssps/|access-date=2021-04-05|website=stratigraphy.org}}</ref> However, [[Diachronism|diachronous]] FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances.<ref name=":0" /><ref>{{Cite journal|last1=Servais|first1=Thomas|last2=Molyneux|first2=Stewart G.|last3=Li|first3=Jun|last4=Nowak|first4=Hendrik|last5=Rubinstein|first5=Claudia V.|last6=Vecoli|first6=Marco|last7=Wang|first7=Wen Hui|last8=Yan|first8=Kui|date=2018|title=First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12248|journal=Lethaia|language=en|volume=51|issue=2|pages=248|doi=10.1111/let.12248|issn=1502-3931}}</ref> Use of other data, such as [[Radiometric dating|radiometric data]], may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units.<ref>{{Cite journal|last1=Pasquo|first1=Mercedes di|last2=Grader|first2=George W.|last3=Isaacson|first3=Peter|last4=Souza|first4=Paulo A.|last5=Iannuzzi|first5=Roberto|last6=Díaz-Martínez|first6=Enrique|date=2015-10-03|title=Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia|url=https://doi.org/10.1080/08912963.2014.910204|journal=Historical Biology|volume=27|issue=7|pages=891|doi=10.1080/08912963.2014.910204|issn=0891-2963|s2cid=129872538}}</ref></div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>FADs are frequently used to designate segments in the [[geologic time scale]]. A given FAD can be used to define a [[Global Boundary Stratotype Section and Point]] (GSSP).<ref name=":0" /> For example, the beginning of the [[Tremadocian]] Stage of the [[Ordovician]] Period is marked by the first appearance of the [[conodont]] ''Iapetognathus fluctivagus'' in the geologic record. This occurs in [[Stratigraphy|bed]] 23 of the rock formation known as the Green Point section, located in western [[Newfoundland (island)|Newfoundland]], as well as in geologically correlated [[Stratum|strata]] in many parts of the world.<ref>{{Cite web|title=International Commission on Stratigraphy|url=https://stratigraphy.org/gssps/|access-date=2021-04-05|website=stratigraphy.org}}</ref> However, [[Diachronism|diachronous]] FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances.<ref name=":0" /><ref>{{Cite journal|last1=Servais|first1=Thomas|last2=Molyneux|first2=Stewart G.|last3=Li|first3=Jun|last4=Nowak|first4=Hendrik|last5=Rubinstein|first5=Claudia V.|last6=Vecoli|first6=Marco|last7=Wang|first7=Wen Hui|last8=Yan|first8=Kui|date=2018|title=First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12248|journal=Lethaia|language=en|volume=51|issue=2|pages=248|doi=10.1111/let.12248|issn=1502-3931}}</ref> Use of other data, such as [[Radiometric dating|radiometric data]], may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units.<ref>{{Cite journal|last1=Pasquo|first1=Mercedes di|last2=Grader|first2=George W.|last3=Isaacson|first3=Peter|last4=Souza|first4=Paulo A.|last5=Iannuzzi|first5=Roberto|last6=Díaz-Martínez|first6=Enrique|date=2015-10-03|title=Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia|url=https://doi.org/10.1080/08912963.2014.910204|journal=Historical Biology|volume=27|issue=7|pages=891|doi=10.1080/08912963.2014.910204|issn=0891-2963|s2cid=129872538}}</ref></div></td>
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</table>HeyElliotthttps://en.wikipedia.org/w/index.php?title=First_appearance_datum&diff=1167430334&oldid=prevFadesga: /* External links */2023-07-27T18:15:48Z<p><span class="autocomment">External links</span></p>
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</table>Fadesgahttps://en.wikipedia.org/w/index.php?title=First_appearance_datum&diff=1116599691&oldid=prevKeith D: Reverted edits by 41.113.225.129 (talk) to last version by Epolk2022-10-17T11:25:14Z<p>Reverted edits by <a href="/wiki/Special:Contributions/41.113.225.129" title="Special:Contributions/41.113.225.129">41.113.225.129</a> (<a href="/w/index.php?title=User_talk:41.113.225.129&action=edit&redlink=1" class="new" title="User talk:41.113.225.129 (page does not exist)">talk</a>) to last version by Epolk</p>
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Previous revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 11:25, 17 October 2022</td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>{{Short description|Term to designate the first appearance of a species in the geologic record}}</div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>{{Short description|Term to designate the first appearance of a species in the geologic record}}</div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are <del style="font-weight: bold; text-decoration: none;">determineG&d</del> by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref <del style="font-weight: bold; text-decoration: none;">naygyyg&Jj</del>=":0">{{Cite journal|<del style="font-weight: bold; text-decoration: none;">l]hjuu$&--jast1</del>=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=<del style="font-weight: bold; text-decoration: none;">Bowringgy</del>|first4=Samuel A.|date=August <del style="font-weight: bold; text-decoration: none;">dyhUtddrrrrh2013</del>|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web|title=Last-appearance datum|url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526|url-status=live|access-date=2021-<del style="font-weight: bold; text-decoration: none;">J$</del>-22|<del style="font-weight: bold; text-decoration: none;">websidte</del>=<del style="font-weight: bold; text-decoration: none;">rt</del> Reference|<del style="font-weight: bold; text-decoration: none;">languytage</del>=<del style="font-weight: bold; text-decoration: none;">engjgujh</del>}}<<del style="font-weight: bold; text-decoration: none;">_&$gdd</del>/ref> </div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are <ins style="font-weight: bold; text-decoration: none;">determined</ins> by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref <ins style="font-weight: bold; text-decoration: none;">name</ins>=":0">{{Cite journal|<ins style="font-weight: bold; text-decoration: none;">last1</ins>=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=<ins style="font-weight: bold; text-decoration: none;">Bowring</ins>|first4=Samuel A.|date=August <ins style="font-weight: bold; text-decoration: none;">2013</ins>|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web|title=Last-appearance datum|url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526|url-status=live|access-date=2021-<ins style="font-weight: bold; text-decoration: none;">04</ins>-22|<ins style="font-weight: bold; text-decoration: none;">website</ins>=<ins style="font-weight: bold; text-decoration: none;">Oxford</ins> Reference|<ins style="font-weight: bold; text-decoration: none;">language</ins>=<ins style="font-weight: bold; text-decoration: none;">en</ins>}}</ref> </div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>FADs are frequently used to designate segments in the [[geologic time scale]]. A given FAD can be used to define a [[Global Boundary Stratotype Section and Point]] (GSSP).<ref name=":0" /> For example, the beginning of the [[Tremadocian]] Stage of the [[Ordovician]] Period is marked by the first appearance of the [[conodont]] ''Iapetognathus fluctivagus'' in the geologic record. This occurs in [[Stratigraphy|bed]] 23 of the rock formation known as the Green Point section, located in western [[Newfoundland (island)|Newfoundland]], as well as in geologically correlated [[Stratum|strata]] in many parts of the world.<ref>{{Cite web|title=International Commission on Stratigraphy|url=https://stratigraphy.org/gssps/|access-date=2021-04-05|website=stratigraphy.org}}</ref> However, [[Diachronism|diachronous]] FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances.<ref name=":0" /><ref>{{Cite journal|last1=Servais|first1=Thomas|last2=Molyneux|first2=Stewart G.|last3=Li|first3=Jun|last4=Nowak|first4=Hendrik|last5=Rubinstein|first5=Claudia V.|last6=Vecoli|first6=Marco|last7=Wang|first7=Wen Hui|last8=Yan|first8=Kui|date=2018|title=First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12248|journal=Lethaia|language=en|volume=51|issue=2|pages=248|doi=10.1111/let.12248|issn=1502-3931}}</ref> Use of other data, such as [[Radiometric dating|radiometric data]], may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units.<ref>{{Cite journal|last1=Pasquo|first1=Mercedes di|last2=Grader|first2=George W.|last3=Isaacson|first3=Peter|last4=Souza|first4=Paulo A.|last5=Iannuzzi|first5=Roberto|last6=Díaz-Martínez|first6=Enrique|date=2015-10-03|title=Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia|url=https://doi.org/10.1080/08912963.2014.910204|journal=Historical Biology|volume=27|issue=7|pages=891|doi=10.1080/08912963.2014.910204|issn=0891-2963|s2cid=129872538}}</ref></div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>FADs are frequently used to designate segments in the [[geologic time scale]]. A given FAD can be used to define a [[Global Boundary Stratotype Section and Point]] (GSSP).<ref name=":0" /> For example, the beginning of the [[Tremadocian]] Stage of the [[Ordovician]] Period is marked by the first appearance of the [[conodont]] ''Iapetognathus fluctivagus'' in the geologic record. This occurs in [[Stratigraphy|bed]] 23 of the rock formation known as the Green Point section, located in western [[Newfoundland (island)|Newfoundland]], as well as in geologically correlated [[Stratum|strata]] in many parts of the world.<ref>{{Cite web|title=International Commission on Stratigraphy|url=https://stratigraphy.org/gssps/|access-date=2021-04-05|website=stratigraphy.org}}</ref> However, [[Diachronism|diachronous]] FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances.<ref name=":0" /><ref>{{Cite journal|last1=Servais|first1=Thomas|last2=Molyneux|first2=Stewart G.|last3=Li|first3=Jun|last4=Nowak|first4=Hendrik|last5=Rubinstein|first5=Claudia V.|last6=Vecoli|first6=Marco|last7=Wang|first7=Wen Hui|last8=Yan|first8=Kui|date=2018|title=First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12248|journal=Lethaia|language=en|volume=51|issue=2|pages=248|doi=10.1111/let.12248|issn=1502-3931}}</ref> Use of other data, such as [[Radiometric dating|radiometric data]], may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units.<ref>{{Cite journal|last1=Pasquo|first1=Mercedes di|last2=Grader|first2=George W.|last3=Isaacson|first3=Peter|last4=Souza|first4=Paulo A.|last5=Iannuzzi|first5=Roberto|last6=Díaz-Martínez|first6=Enrique|date=2015-10-03|title=Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia|url=https://doi.org/10.1080/08912963.2014.910204|journal=Historical Biology|volume=27|issue=7|pages=891|doi=10.1080/08912963.2014.910204|issn=0891-2963|s2cid=129872538}}</ref></div></td>
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</table>Keith Dhttps://en.wikipedia.org/w/index.php?title=First_appearance_datum&diff=1116581642&oldid=prev41.113.225.129 at 08:44, 17 October 20222022-10-17T08:44:32Z<p></p>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>{{Short description|Term to designate the first appearance of a species in the geologic record}}</div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are <del style="font-weight: bold; text-decoration: none;">determined</del> by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref <del style="font-weight: bold; text-decoration: none;">name</del>=":0">{{Cite journal|<del style="font-weight: bold; text-decoration: none;">last1</del>=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=<del style="font-weight: bold; text-decoration: none;">Bowring</del>|first4=Samuel A.|date=August <del style="font-weight: bold; text-decoration: none;">2013</del>|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web|title=Last-appearance datum|url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526|url-status=live|access-date=2021-<del style="font-weight: bold; text-decoration: none;">04</del>-22|<del style="font-weight: bold; text-decoration: none;">website</del>=<del style="font-weight: bold; text-decoration: none;">Oxford</del> Reference|<del style="font-weight: bold; text-decoration: none;">language</del>=<del style="font-weight: bold; text-decoration: none;">en</del>}}</ref> </div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are <ins style="font-weight: bold; text-decoration: none;">determineG&d</ins> by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref <ins style="font-weight: bold; text-decoration: none;">naygyyg&Jj</ins>=":0">{{Cite journal|<ins style="font-weight: bold; text-decoration: none;">l]hjuu$&--jast1</ins>=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=<ins style="font-weight: bold; text-decoration: none;">Bowringgy</ins>|first4=Samuel A.|date=August <ins style="font-weight: bold; text-decoration: none;">dyhUtddrrrrh2013</ins>|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web|title=Last-appearance datum|url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526|url-status=live|access-date=2021-<ins style="font-weight: bold; text-decoration: none;">J$</ins>-22|<ins style="font-weight: bold; text-decoration: none;">websidte</ins>=<ins style="font-weight: bold; text-decoration: none;">rt</ins> Reference|<ins style="font-weight: bold; text-decoration: none;">languytage</ins>=<ins style="font-weight: bold; text-decoration: none;">engjgujh</ins>}}<<ins style="font-weight: bold; text-decoration: none;">_&$gdd</ins>/ref> </div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>FADs are frequently used to designate segments in the [[geologic time scale]]. A given FAD can be used to define a [[Global Boundary Stratotype Section and Point]] (GSSP).<ref name=":0" /> For example, the beginning of the [[Tremadocian]] Stage of the [[Ordovician]] Period is marked by the first appearance of the [[conodont]] ''Iapetognathus fluctivagus'' in the geologic record. This occurs in [[Stratigraphy|bed]] 23 of the rock formation known as the Green Point section, located in western [[Newfoundland (island)|Newfoundland]], as well as in geologically correlated [[Stratum|strata]] in many parts of the world.<ref>{{Cite web|title=International Commission on Stratigraphy|url=https://stratigraphy.org/gssps/|access-date=2021-04-05|website=stratigraphy.org}}</ref> However, [[Diachronism|diachronous]] FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances.<ref name=":0" /><ref>{{Cite journal|last1=Servais|first1=Thomas|last2=Molyneux|first2=Stewart G.|last3=Li|first3=Jun|last4=Nowak|first4=Hendrik|last5=Rubinstein|first5=Claudia V.|last6=Vecoli|first6=Marco|last7=Wang|first7=Wen Hui|last8=Yan|first8=Kui|date=2018|title=First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12248|journal=Lethaia|language=en|volume=51|issue=2|pages=248|doi=10.1111/let.12248|issn=1502-3931}}</ref> Use of other data, such as [[Radiometric dating|radiometric data]], may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units.<ref>{{Cite journal|last1=Pasquo|first1=Mercedes di|last2=Grader|first2=George W.|last3=Isaacson|first3=Peter|last4=Souza|first4=Paulo A.|last5=Iannuzzi|first5=Roberto|last6=Díaz-Martínez|first6=Enrique|date=2015-10-03|title=Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia|url=https://doi.org/10.1080/08912963.2014.910204|journal=Historical Biology|volume=27|issue=7|pages=891|doi=10.1080/08912963.2014.910204|issn=0891-2963|s2cid=129872538}}</ref></div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>FADs are frequently used to designate segments in the [[geologic time scale]]. A given FAD can be used to define a [[Global Boundary Stratotype Section and Point]] (GSSP).<ref name=":0" /> For example, the beginning of the [[Tremadocian]] Stage of the [[Ordovician]] Period is marked by the first appearance of the [[conodont]] ''Iapetognathus fluctivagus'' in the geologic record. This occurs in [[Stratigraphy|bed]] 23 of the rock formation known as the Green Point section, located in western [[Newfoundland (island)|Newfoundland]], as well as in geologically correlated [[Stratum|strata]] in many parts of the world.<ref>{{Cite web|title=International Commission on Stratigraphy|url=https://stratigraphy.org/gssps/|access-date=2021-04-05|website=stratigraphy.org}}</ref> However, [[Diachronism|diachronous]] FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances.<ref name=":0" /><ref>{{Cite journal|last1=Servais|first1=Thomas|last2=Molyneux|first2=Stewart G.|last3=Li|first3=Jun|last4=Nowak|first4=Hendrik|last5=Rubinstein|first5=Claudia V.|last6=Vecoli|first6=Marco|last7=Wang|first7=Wen Hui|last8=Yan|first8=Kui|date=2018|title=First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12248|journal=Lethaia|language=en|volume=51|issue=2|pages=248|doi=10.1111/let.12248|issn=1502-3931}}</ref> Use of other data, such as [[Radiometric dating|radiometric data]], may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units.<ref>{{Cite journal|last1=Pasquo|first1=Mercedes di|last2=Grader|first2=George W.|last3=Isaacson|first3=Peter|last4=Souza|first4=Paulo A.|last5=Iannuzzi|first5=Roberto|last6=Díaz-Martínez|first6=Enrique|date=2015-10-03|title=Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia|url=https://doi.org/10.1080/08912963.2014.910204|journal=Historical Biology|volume=27|issue=7|pages=891|doi=10.1080/08912963.2014.910204|issn=0891-2963|s2cid=129872538}}</ref></div></td>
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</table>41.113.225.129https://en.wikipedia.org/w/index.php?title=First_appearance_datum&diff=1067519358&oldid=prevEpolk at 22:27, 23 January 20222022-01-23T22:27:37Z<p></p>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>{{Short description|Term<del style="font-weight: bold; text-decoration: none;"> used by geologists and paleontologists</del> to designate the first appearance of a species in the geologic record}}</div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>{{Short description|Term to designate the first appearance of a species in the geologic record}}</div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref name=":0">{{Cite journal|last1=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=Bowring|first4=Samuel A.|date=August 2013|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web|title=Last-appearance datum|url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526|url-status=live|access-date=2021-04-22|website=Oxford Reference|language=en}}</ref> </div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref name=":0">{{Cite journal|last1=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=Bowring|first4=Samuel A.|date=August 2013|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web|title=Last-appearance datum|url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526|url-status=live|access-date=2021-04-22|website=Oxford Reference|language=en}}</ref> </div></td>
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</table>Epolkhttps://en.wikipedia.org/w/index.php?title=First_appearance_datum&diff=1067519243&oldid=prevEpolk at 22:26, 23 January 20222022-01-23T22:26:41Z<p></p>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>{{Short description|Term used by geologists and paleontologists to designate the first appearance of a species in the geologic record}}</div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref name=":0">{{Cite journal|last1=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=Bowring|first4=Samuel A.|date=August 2013|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web|title=Last-appearance datum|url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526|url-status=live|access-date=2021-04-22|website=Oxford Reference|language=en}}</ref> </div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref name=":0">{{Cite journal|last1=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=Bowring|first4=Samuel A.|date=August 2013|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web|title=Last-appearance datum|url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526|url-status=live|access-date=2021-04-22|website=Oxford Reference|language=en}}</ref> </div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>FADs are frequently used to designate segments in the [[geologic time scale]]. A given FAD can be used to define a [[Global Boundary Stratotype Section and Point]] (GSSP).<ref name=":0" /> For example, the beginning of the [[Tremadocian]] Stage of the [[Ordovician]] Period is marked by the first appearance of the [[conodont]] ''Iapetognathus fluctivagus'' in the geologic record. This occurs in [[Stratigraphy|bed]] 23 of the rock formation known as the Green Point section, located in western [[Newfoundland (island)|Newfoundland]], as well as in geologically correlated [[Stratum|strata]] in many parts of the world.<ref>{{Cite web|title=International Commission on Stratigraphy|url=https://stratigraphy.org/gssps/|access-date=2021-04-05|website=stratigraphy.org}}</ref> However, [[Diachronism|diachronous]] FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances.<ref name=":0" /><ref>{{Cite journal|last1=Servais|first1=Thomas|last2=Molyneux|first2=Stewart G.|last3=Li|first3=Jun|last4=Nowak|first4=Hendrik|last5=Rubinstein|first5=Claudia V.|last6=Vecoli|first6=Marco|last7=Wang|first7=Wen Hui|last8=Yan|first8=Kui|date=2018|title=First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12248|journal=Lethaia|language=en|volume=51|issue=2|pages=248|doi=10.1111/let.12248|issn=1502-3931}}</ref> Use of other data, such as [[Radiometric dating|radiometric data]], may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units.<ref>{{Cite journal|last1=Pasquo|first1=Mercedes di|last2=Grader|first2=George W.|last3=Isaacson|first3=Peter|last4=Souza|first4=Paulo A.|last5=Iannuzzi|first5=Roberto|last6=Díaz-Martínez|first6=Enrique|date=2015-10-03|title=Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia|url=https://doi.org/10.1080/08912963.2014.910204|journal=Historical Biology|volume=27|issue=7|pages=891|doi=10.1080/08912963.2014.910204|issn=0891-2963|s2cid=129872538}}</ref><del style="font-weight: bold; text-decoration: none;"> </del></div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>FADs are frequently used to designate segments in the [[geologic time scale]]. A given FAD can be used to define a [[Global Boundary Stratotype Section and Point]] (GSSP).<ref name=":0" /> For example, the beginning of the [[Tremadocian]] Stage of the [[Ordovician]] Period is marked by the first appearance of the [[conodont]] ''Iapetognathus fluctivagus'' in the geologic record. This occurs in [[Stratigraphy|bed]] 23 of the rock formation known as the Green Point section, located in western [[Newfoundland (island)|Newfoundland]], as well as in geologically correlated [[Stratum|strata]] in many parts of the world.<ref>{{Cite web|title=International Commission on Stratigraphy|url=https://stratigraphy.org/gssps/|access-date=2021-04-05|website=stratigraphy.org}}</ref> However, [[Diachronism|diachronous]] FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances.<ref name=":0" /><ref>{{Cite journal|last1=Servais|first1=Thomas|last2=Molyneux|first2=Stewart G.|last3=Li|first3=Jun|last4=Nowak|first4=Hendrik|last5=Rubinstein|first5=Claudia V.|last6=Vecoli|first6=Marco|last7=Wang|first7=Wen Hui|last8=Yan|first8=Kui|date=2018|title=First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12248|journal=Lethaia|language=en|volume=51|issue=2|pages=248|doi=10.1111/let.12248|issn=1502-3931}}</ref> Use of other data, such as [[Radiometric dating|radiometric data]], may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units.<ref>{{Cite journal|last1=Pasquo|first1=Mercedes di|last2=Grader|first2=George W.|last3=Isaacson|first3=Peter|last4=Souza|first4=Paulo A.|last5=Iannuzzi|first5=Roberto|last6=Díaz-Martínez|first6=Enrique|date=2015-10-03|title=Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia|url=https://doi.org/10.1080/08912963.2014.910204|journal=Historical Biology|volume=27|issue=7|pages=891|doi=10.1080/08912963.2014.910204|issn=0891-2963|s2cid=129872538}}</ref></div></td>
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</table>Epolkhttps://en.wikipedia.org/w/index.php?title=First_appearance_datum&diff=1025302788&oldid=prevRVSNS: Made page range more specific for source2021-05-26T20:54:58Z<p>Made page range more specific for source</p>
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 20:54, 26 May 2021</td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref name=":0">{{Cite journal|last1=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=Bowring|first4=Samuel A.|date=August 2013|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web|title=Last-appearance datum|url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526|url-status=live|access-date=2021-04-22|website=Oxford Reference|language=en}}</ref> </div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>'''First appearance datum''' (FAD) is a term used by [[geologist]]s and [[Paleontology|paleontologists]] to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest [[fossil]] discovered, to date, of a particular species.<ref name=":0">{{Cite journal|last1=Landing|first1=Ed|last2=Geyer|first2=Gerd|last3=Brasier|first3=Martin D.|last4=Bowring|first4=Samuel A.|date=August 2013|title=Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept|url=https://ui.adsabs.harvard.edu/abs/2013ESRv..123..133L/abstract|journal=Earth-Science Reviews|volume=123|pages=135|doi=10.1016/j.earscirev.2013.03.008|bibcode=2013ESRv..123..133L|via=Astrophysics Data System}}</ref> A related term is last appearance datum (LAD), the last appearance of a species in the geologic record.<ref>{{Cite web|title=Last-appearance datum|url=https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100052526|url-status=live|access-date=2021-04-22|website=Oxford Reference|language=en}}</ref> </div></td>
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<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>FADs are frequently used to designate segments in the [[geologic time scale]]. A given FAD can be used to define a [[Global Boundary Stratotype Section and Point]] (GSSP).<ref name=":0" /> For example, the beginning of the [[Tremadocian]] Stage of the [[Ordovician]] Period is marked by the first appearance of the [[conodont]] ''Iapetognathus fluctivagus'' in the geologic record. This occurs in [[Stratigraphy|bed]] 23 of the rock formation known as the Green Point section, located in western [[Newfoundland (island)|Newfoundland]], as well as in geologically correlated [[Stratum|strata]] in many parts of the world.<ref>{{Cite web|title=International Commission on Stratigraphy|url=https://stratigraphy.org/gssps/|access-date=2021-04-05|website=stratigraphy.org}}</ref> However, [[Diachronism|diachronous]] FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances.<ref name=":0" /><ref>{{Cite journal|last1=Servais|first1=Thomas|last2=Molyneux|first2=Stewart G.|last3=Li|first3=Jun|last4=Nowak|first4=Hendrik|last5=Rubinstein|first5=Claudia V.|last6=Vecoli|first6=Marco|last7=Wang|first7=Wen Hui|last8=Yan|first8=Kui|date=2018|title=First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12248|journal=Lethaia|language=en|volume=51|issue=2|pages=248|doi=10.1111/let.12248|issn=1502-3931}}</ref> Use of other data, such as [[Radiometric dating|radiometric data]], may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units.<ref>{{Cite journal|last1=Pasquo|first1=Mercedes di|last2=Grader|first2=George W.|last3=Isaacson|first3=Peter|last4=Souza|first4=Paulo A.|last5=Iannuzzi|first5=Roberto|last6=Díaz-Martínez|first6=Enrique|date=2015-10-03|title=Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia|url=https://doi.org/10.1080/08912963.2014.910204|journal=Historical Biology|volume=27|issue=7|pages=<del style="font-weight: bold; text-decoration: none;">868–897</del>|doi=10.1080/08912963.2014.910204<del style="font-weight: bold; text-decoration: none;">|s2cid=129872538</del>|issn=0891-2963}}</ref> </div></td>
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<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>FADs are frequently used to designate segments in the [[geologic time scale]]. A given FAD can be used to define a [[Global Boundary Stratotype Section and Point]] (GSSP).<ref name=":0" /> For example, the beginning of the [[Tremadocian]] Stage of the [[Ordovician]] Period is marked by the first appearance of the [[conodont]] ''Iapetognathus fluctivagus'' in the geologic record. This occurs in [[Stratigraphy|bed]] 23 of the rock formation known as the Green Point section, located in western [[Newfoundland (island)|Newfoundland]], as well as in geologically correlated [[Stratum|strata]] in many parts of the world.<ref>{{Cite web|title=International Commission on Stratigraphy|url=https://stratigraphy.org/gssps/|access-date=2021-04-05|website=stratigraphy.org}}</ref> However, [[Diachronism|diachronous]] FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances.<ref name=":0" /><ref>{{Cite journal|last1=Servais|first1=Thomas|last2=Molyneux|first2=Stewart G.|last3=Li|first3=Jun|last4=Nowak|first4=Hendrik|last5=Rubinstein|first5=Claudia V.|last6=Vecoli|first6=Marco|last7=Wang|first7=Wen Hui|last8=Yan|first8=Kui|date=2018|title=First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician stages|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12248|journal=Lethaia|language=en|volume=51|issue=2|pages=248|doi=10.1111/let.12248|issn=1502-3931}}</ref> Use of other data, such as [[Radiometric dating|radiometric data]], may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units.<ref>{{Cite journal|last1=Pasquo|first1=Mercedes di|last2=Grader|first2=George W.|last3=Isaacson|first3=Peter|last4=Souza|first4=Paulo A.|last5=Iannuzzi|first5=Roberto|last6=Díaz-Martínez|first6=Enrique|date=2015-10-03|title=Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia|url=https://doi.org/10.1080/08912963.2014.910204|journal=Historical Biology|volume=27|issue=7|pages=<ins style="font-weight: bold; text-decoration: none;">891</ins>|doi=10.1080/08912963.2014.910204|issn=0891-2963<ins style="font-weight: bold; text-decoration: none;">|s2cid=129872538</ins>}}</ref> </div></td>
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