Diversity and Evolution of Silurian Radiolarians
The three approaches followed herein aim to improve our understanding of the paleobiodiversity andevolution of Silurian radiolarians. The first approach provides an exhaustive taxonomic description ofan entirely new radiolarian fauna recovered from two sections of the Cape Phillips Formation in theC...
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Uppsala universitet, Institutionen för geovetenskaper
2016
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ftuppsalauniv:oai:DiVA.org:uu-281707 2023-05-15T15:01:51+02:00 Diversity and Evolution of Silurian Radiolarians Diversitet och evolution hos siluriska radiolarier Tetard, Martin 2016 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-281707 eng eng Uppsala universitet, Institutionen för geovetenskaper Examensarbete vid Institutionen för geovetenskaper, 1650-6553 351 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-281707 info:eu-repo/semantics/openAccess Radiolaria Silurian Canadian Arctic Paleobiodiversity Diversity trends CT-Scan silur diversitetsmönster kanadensiska Arktis Student thesis info:eu-repo/semantics/bachelorThesis text 2016 ftuppsalauniv 2023-02-23T21:38:03Z The three approaches followed herein aim to improve our understanding of the paleobiodiversity andevolution of Silurian radiolarians. The first approach provides an exhaustive taxonomic description ofan entirely new radiolarian fauna recovered from two sections of the Cape Phillips Formation in theCanadian Arctic which accumulated in two different paleoenvironmental settings. The samples are datedby graptolites of the Gorstian Lobograptus progenitor Zone. The obtained radiolarian fauna includes 28species, of which 3 are new, and exhibits some of the best preserved Silurian radiolarians known so far.The stratigraphic range of several species was also extended. Then, in a second approach, a CT-Scan3D reconstruction of a specimen of Gyrosphaera cavea was conducted in order to resolve significantinternal structure taxonomic issues. Higher level radiolarian classification is based on internal structures,and classical methods of observing these features repeatedly failed to uncover them. The 3D imagingrevealed a «double» coiling of the specimen that has proved useful in understanding how it grew.Eventually, the third approach is a completion of published taxonomic works in the Silurian with theaim of providing diversity trends through analyses of these radiolarian occurrences. A biotic crisis canbe observed in the Homerian, exhibiting both high extinction and low origination rates, and may belinked with enhanced marine productivity. De tre projekten som utvecklas här har som mål att fokusera på trender inom evolutionen ochmångfalden av en grupp planktoniska mikroorganismer från Silur (från -443 till -419 Ma). I ett förstaprojekt beskrivs en helt ny fauna radiolarier som hittats i två lokaliteter på de kanadensiska arktiskaöarna, och som har deponerats i olika miljöförhållanden under Silur. Detta material daterades med hjälpav graptoliter, en grupp utdöda svalgsträngsdjur som är mycket användbara för paleozoiska dateringar,till en ålder överensstämmande med Gorstian (-427 till -425 Ma). Denna kanadensisk-arktiska ... Bachelor Thesis Arctic Arktis Arktis* Uppsala University: Publications (DiVA) Arctic Cape Phillips ENVELOPE(-62.600,-62.600,-84.750,-84.750) |
institution |
Open Polar |
collection |
Uppsala University: Publications (DiVA) |
op_collection_id |
ftuppsalauniv |
language |
English |
topic |
Radiolaria Silurian Canadian Arctic Paleobiodiversity Diversity trends CT-Scan silur diversitetsmönster kanadensiska Arktis |
spellingShingle |
Radiolaria Silurian Canadian Arctic Paleobiodiversity Diversity trends CT-Scan silur diversitetsmönster kanadensiska Arktis Tetard, Martin Diversity and Evolution of Silurian Radiolarians |
topic_facet |
Radiolaria Silurian Canadian Arctic Paleobiodiversity Diversity trends CT-Scan silur diversitetsmönster kanadensiska Arktis |
description |
The three approaches followed herein aim to improve our understanding of the paleobiodiversity andevolution of Silurian radiolarians. The first approach provides an exhaustive taxonomic description ofan entirely new radiolarian fauna recovered from two sections of the Cape Phillips Formation in theCanadian Arctic which accumulated in two different paleoenvironmental settings. The samples are datedby graptolites of the Gorstian Lobograptus progenitor Zone. The obtained radiolarian fauna includes 28species, of which 3 are new, and exhibits some of the best preserved Silurian radiolarians known so far.The stratigraphic range of several species was also extended. Then, in a second approach, a CT-Scan3D reconstruction of a specimen of Gyrosphaera cavea was conducted in order to resolve significantinternal structure taxonomic issues. Higher level radiolarian classification is based on internal structures,and classical methods of observing these features repeatedly failed to uncover them. The 3D imagingrevealed a «double» coiling of the specimen that has proved useful in understanding how it grew.Eventually, the third approach is a completion of published taxonomic works in the Silurian with theaim of providing diversity trends through analyses of these radiolarian occurrences. A biotic crisis canbe observed in the Homerian, exhibiting both high extinction and low origination rates, and may belinked with enhanced marine productivity. De tre projekten som utvecklas här har som mål att fokusera på trender inom evolutionen ochmångfalden av en grupp planktoniska mikroorganismer från Silur (från -443 till -419 Ma). I ett förstaprojekt beskrivs en helt ny fauna radiolarier som hittats i två lokaliteter på de kanadensiska arktiskaöarna, och som har deponerats i olika miljöförhållanden under Silur. Detta material daterades med hjälpav graptoliter, en grupp utdöda svalgsträngsdjur som är mycket användbara för paleozoiska dateringar,till en ålder överensstämmande med Gorstian (-427 till -425 Ma). Denna kanadensisk-arktiska ... |
format |
Bachelor Thesis |
author |
Tetard, Martin |
author_facet |
Tetard, Martin |
author_sort |
Tetard, Martin |
title |
Diversity and Evolution of Silurian Radiolarians |
title_short |
Diversity and Evolution of Silurian Radiolarians |
title_full |
Diversity and Evolution of Silurian Radiolarians |
title_fullStr |
Diversity and Evolution of Silurian Radiolarians |
title_full_unstemmed |
Diversity and Evolution of Silurian Radiolarians |
title_sort |
diversity and evolution of silurian radiolarians |
publisher |
Uppsala universitet, Institutionen för geovetenskaper |
publishDate |
2016 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-281707 |
long_lat |
ENVELOPE(-62.600,-62.600,-84.750,-84.750) |
geographic |
Arctic Cape Phillips |
geographic_facet |
Arctic Cape Phillips |
genre |
Arctic Arktis Arktis* |
genre_facet |
Arctic Arktis Arktis* |
op_relation |
Examensarbete vid Institutionen för geovetenskaper, 1650-6553 351 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-281707 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766333864249131008 |