Toarcian (Lower Jurassic) ammonite biostratigraphy and ammonite fauna of North America
Toarcian ammonite collections from British Columbia, Nevada, Oregon, the Yukon, and Alaska form the basis of a detailed taxonomic study. Fifty-seven species are described, allocated to 27 genera, one of which is new ( Yakounia). Nine new species are introduced: Yakouma yakounensis, Y. pacifica, Y. f...
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ftunivbritcolcir:oai:circle.library.ubc.ca:2429/2990 2023-05-15T15:03:43+02:00 Toarcian (Lower Jurassic) ammonite biostratigraphy and ammonite fauna of North America Jakobs, ,Giselle Kathleen 1992 17619082 bytes application/pdf http://hdl.handle.net/2429/2990 eng eng For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. Text Thesis/Dissertation 1992 ftunivbritcolcir 2019-10-15T17:44:12Z Toarcian ammonite collections from British Columbia, Nevada, Oregon, the Yukon, and Alaska form the basis of a detailed taxonomic study. Fifty-seven species are described, allocated to 27 genera, one of which is new ( Yakounia). Nine new species are introduced: Yakouma yakounensis, Y. pacifica, Y. freboldi, Y. silvae, Pleydellia maudensis, P.crassiornata, Phymatoceras hillebrandti, Leukadiella n. sp. A, and Leukadiella n. sp. B. Measured sections from the Queen Charlotte Islands and other key areas in western North America were used to distinguish six successive assemblage zones: Kanense, Levisoni, lonica, Crassicosta, Hillebrandti, and Yakounensis. All six zones, which can be recognized from southern Alaska to Nevada, are defined here for the first time. The Arctic basins (Sverdrup and Brooks-MacKenzie) have a low diversity ammonite faunal sequence similar to that of Siberia and the zonation developed there can be used in Arctic North America. The Toarcian of western North America is most commonly represented by argillaceous sediments. On the craton, in t.he Sverdrup basin, a transgression in the Middle Toarcian suggests a link with eustatic sea level changes. On the terranes, two intervals of coarser grained sedimentation can be recognized, one during the Crassicosta Zone and one during the Yakounensis Zone and continuing into the Aalenian. These intervals are also probably related to eustatic sea level changes. A paleobiogeographic study of the similarity of ammonite faunas between different areas used two methods: a Monte Carlo simulation, in which randomly generated data sets provide confidence levels for similarity coefficients, and complete linkage cluster analysis. The Monte Carlo method corrects for sparseness in the data set., cluster analysis does not and should be used with caution in similar studies. The ammonite fauna of westeril North America includes taxa with pandemic, Tethyan, Boreal, Pacific, East Pacific, and Athabascan affinities. Several possible migration routes exist that could explain the similarity of western North American faunas to those of western Tethys. An analysis of the similarity of the western North American fauna to other areas, at the generic level. shows that migration of endemic forms occurred via the Hispanic Corridor, coinciding with periods of high sea level. Science, Faculty of Earth, Ocean and Atmospheric Sciences, Department of Graduate Thesis Arctic Athabascan sverdrup basin Alaska Siberia Yukon University of British Columbia: cIRcle - UBC's Information Repository Arctic Yukon Pacific Queen Charlotte ENVELOPE(-132.088,-132.088,53.255,53.255) |
institution |
Open Polar |
collection |
University of British Columbia: cIRcle - UBC's Information Repository |
op_collection_id |
ftunivbritcolcir |
language |
English |
description |
Toarcian ammonite collections from British Columbia, Nevada, Oregon, the Yukon, and Alaska form the basis of a detailed taxonomic study. Fifty-seven species are described, allocated to 27 genera, one of which is new ( Yakounia). Nine new species are introduced: Yakouma yakounensis, Y. pacifica, Y. freboldi, Y. silvae, Pleydellia maudensis, P.crassiornata, Phymatoceras hillebrandti, Leukadiella n. sp. A, and Leukadiella n. sp. B. Measured sections from the Queen Charlotte Islands and other key areas in western North America were used to distinguish six successive assemblage zones: Kanense, Levisoni, lonica, Crassicosta, Hillebrandti, and Yakounensis. All six zones, which can be recognized from southern Alaska to Nevada, are defined here for the first time. The Arctic basins (Sverdrup and Brooks-MacKenzie) have a low diversity ammonite faunal sequence similar to that of Siberia and the zonation developed there can be used in Arctic North America. The Toarcian of western North America is most commonly represented by argillaceous sediments. On the craton, in t.he Sverdrup basin, a transgression in the Middle Toarcian suggests a link with eustatic sea level changes. On the terranes, two intervals of coarser grained sedimentation can be recognized, one during the Crassicosta Zone and one during the Yakounensis Zone and continuing into the Aalenian. These intervals are also probably related to eustatic sea level changes. A paleobiogeographic study of the similarity of ammonite faunas between different areas used two methods: a Monte Carlo simulation, in which randomly generated data sets provide confidence levels for similarity coefficients, and complete linkage cluster analysis. The Monte Carlo method corrects for sparseness in the data set., cluster analysis does not and should be used with caution in similar studies. The ammonite fauna of westeril North America includes taxa with pandemic, Tethyan, Boreal, Pacific, East Pacific, and Athabascan affinities. Several possible migration routes exist that could explain the similarity of western North American faunas to those of western Tethys. An analysis of the similarity of the western North American fauna to other areas, at the generic level. shows that migration of endemic forms occurred via the Hispanic Corridor, coinciding with periods of high sea level. Science, Faculty of Earth, Ocean and Atmospheric Sciences, Department of Graduate |
format |
Thesis |
author |
Jakobs, ,Giselle Kathleen |
spellingShingle |
Jakobs, ,Giselle Kathleen Toarcian (Lower Jurassic) ammonite biostratigraphy and ammonite fauna of North America |
author_facet |
Jakobs, ,Giselle Kathleen |
author_sort |
Jakobs, ,Giselle Kathleen |
title |
Toarcian (Lower Jurassic) ammonite biostratigraphy and ammonite fauna of North America |
title_short |
Toarcian (Lower Jurassic) ammonite biostratigraphy and ammonite fauna of North America |
title_full |
Toarcian (Lower Jurassic) ammonite biostratigraphy and ammonite fauna of North America |
title_fullStr |
Toarcian (Lower Jurassic) ammonite biostratigraphy and ammonite fauna of North America |
title_full_unstemmed |
Toarcian (Lower Jurassic) ammonite biostratigraphy and ammonite fauna of North America |
title_sort |
toarcian (lower jurassic) ammonite biostratigraphy and ammonite fauna of north america |
publishDate |
1992 |
url |
http://hdl.handle.net/2429/2990 |
long_lat |
ENVELOPE(-132.088,-132.088,53.255,53.255) |
geographic |
Arctic Yukon Pacific Queen Charlotte |
geographic_facet |
Arctic Yukon Pacific Queen Charlotte |
genre |
Arctic Athabascan sverdrup basin Alaska Siberia Yukon |
genre_facet |
Arctic Athabascan sverdrup basin Alaska Siberia Yukon |
op_rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
_version_ |
1766335567388213248 |