The Placentian Series: appearance of the oldest skeletalized faunas in southeastern Newfoundland
The lowest Cambrian of Avalon, or Placentian Series, is a relatively thick sequence (1,400 m) in southeastern Newfoundland. A newly proposed body fossil zonation supplements an existing trace fossil zonation of the lower part of the Placentian Series and includes strata to the top of the sub-trilobi...
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Cambridge University Press (CUP)
1989
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Online Access: | http://dx.doi.org/10.1017/s0022336000036465 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022336000036465 |
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crcambridgeupr:10.1017/s0022336000036465 2024-10-13T14:09:07+00:00 The Placentian Series: appearance of the oldest skeletalized faunas in southeastern Newfoundland Landing, Ed Myrow, Paul Benus, Alison P. Narbonne, Guy M. 1989 http://dx.doi.org/10.1017/s0022336000036465 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022336000036465 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Journal of Paleontology volume 63, issue 6, page 739-769 ISSN 0022-3360 1937-2337 journal-article 1989 crcambridgeupr https://doi.org/10.1017/s0022336000036465 2024-09-25T04:02:55Z The lowest Cambrian of Avalon, or Placentian Series, is a relatively thick sequence (1,400 m) in southeastern Newfoundland. A newly proposed body fossil zonation supplements an existing trace fossil zonation of the lower part of the Placentian Series and includes strata to the top of the sub-trilobitic Lower Cambrian. The Sabellidites cambriensis Zone brackets the Precambrian–Cambrian boundary and comprises peritidal and wave-influenced subtidal facies deposited during deepening through the lower part of the Chapel Island Formation. Younger “ Ladatheca ” cylindrica Zone strata include the deepest facies of the Chapel Island Formation. The base of the overlying Watsonella crosbyi Zone (a post-Nemakit Daldyn and pre-Tommotian equivalent) is significantly diachronous because the diagnostic mollusks were preferentially preserved in pyritiferous offshore muds rather than in coeval nearshore muds. High diversity, upper Watsonella crosbyi Zone faunas (18 species) are limited to peritidal limestones of member 4 and are dominated by calcareous small shelly fossils. A thick interval (ca. 430 m) without body fossils and an important episode of block faulting that led to 750 m of differential erosion preceded deposition of the lower part of the Bonavista Group (= Sunnaginia imbricata Zone, an interval considered to be largely older than the Tommotian). Although much Early Cambrian time may be lost as a result of erosion at Random Formation–Bonavista Group unconformities, many Watsonella crosbyi Zone species reappear in the Sunnaginia imbricata Zone. Shoaling accompanied the immigration event defining the base of the Camenella baltica Zone, and an unconformity following regional offlap marks the top of the Placentian Series. Calcareous, and not phosphatic, composition is most common in earliest Cambrian shelly remains. Little evidence suggests that a global, Precambrian–Cambrian boundary interval “phosphogenic” event either resulted in deposition of local phosphate deposits in the Tethyan region or had a role in the ... Article in Journal/Newspaper Newfoundland Cambridge University Press Chapel Island ENVELOPE(-55.715,-55.715,52.467,52.467) Journal of Paleontology 63 6 739 769 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
The lowest Cambrian of Avalon, or Placentian Series, is a relatively thick sequence (1,400 m) in southeastern Newfoundland. A newly proposed body fossil zonation supplements an existing trace fossil zonation of the lower part of the Placentian Series and includes strata to the top of the sub-trilobitic Lower Cambrian. The Sabellidites cambriensis Zone brackets the Precambrian–Cambrian boundary and comprises peritidal and wave-influenced subtidal facies deposited during deepening through the lower part of the Chapel Island Formation. Younger “ Ladatheca ” cylindrica Zone strata include the deepest facies of the Chapel Island Formation. The base of the overlying Watsonella crosbyi Zone (a post-Nemakit Daldyn and pre-Tommotian equivalent) is significantly diachronous because the diagnostic mollusks were preferentially preserved in pyritiferous offshore muds rather than in coeval nearshore muds. High diversity, upper Watsonella crosbyi Zone faunas (18 species) are limited to peritidal limestones of member 4 and are dominated by calcareous small shelly fossils. A thick interval (ca. 430 m) without body fossils and an important episode of block faulting that led to 750 m of differential erosion preceded deposition of the lower part of the Bonavista Group (= Sunnaginia imbricata Zone, an interval considered to be largely older than the Tommotian). Although much Early Cambrian time may be lost as a result of erosion at Random Formation–Bonavista Group unconformities, many Watsonella crosbyi Zone species reappear in the Sunnaginia imbricata Zone. Shoaling accompanied the immigration event defining the base of the Camenella baltica Zone, and an unconformity following regional offlap marks the top of the Placentian Series. Calcareous, and not phosphatic, composition is most common in earliest Cambrian shelly remains. Little evidence suggests that a global, Precambrian–Cambrian boundary interval “phosphogenic” event either resulted in deposition of local phosphate deposits in the Tethyan region or had a role in the ... |
format |
Article in Journal/Newspaper |
author |
Landing, Ed Myrow, Paul Benus, Alison P. Narbonne, Guy M. |
spellingShingle |
Landing, Ed Myrow, Paul Benus, Alison P. Narbonne, Guy M. The Placentian Series: appearance of the oldest skeletalized faunas in southeastern Newfoundland |
author_facet |
Landing, Ed Myrow, Paul Benus, Alison P. Narbonne, Guy M. |
author_sort |
Landing, Ed |
title |
The Placentian Series: appearance of the oldest skeletalized faunas in southeastern Newfoundland |
title_short |
The Placentian Series: appearance of the oldest skeletalized faunas in southeastern Newfoundland |
title_full |
The Placentian Series: appearance of the oldest skeletalized faunas in southeastern Newfoundland |
title_fullStr |
The Placentian Series: appearance of the oldest skeletalized faunas in southeastern Newfoundland |
title_full_unstemmed |
The Placentian Series: appearance of the oldest skeletalized faunas in southeastern Newfoundland |
title_sort |
placentian series: appearance of the oldest skeletalized faunas in southeastern newfoundland |
publisher |
Cambridge University Press (CUP) |
publishDate |
1989 |
url |
http://dx.doi.org/10.1017/s0022336000036465 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022336000036465 |
long_lat |
ENVELOPE(-55.715,-55.715,52.467,52.467) |
geographic |
Chapel Island |
geographic_facet |
Chapel Island |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_source |
Journal of Paleontology volume 63, issue 6, page 739-769 ISSN 0022-3360 1937-2337 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0022336000036465 |
container_title |
Journal of Paleontology |
container_volume |
63 |
container_issue |
6 |
container_start_page |
739 |
op_container_end_page |
769 |
_version_ |
1812815977267593216 |