Morphological variability of Globorotalia menardii (planktonic foraminifera) in two DSDP cores from the Caribbean Sea and the Eastern Equatorial Pacific
International audience Variability in the test of Globorotalia menardii during the past 8 million years has been investigated at DSDP Site 502A (Caribbean Sea) and DSDP Site 503A (Eastern Equatorial Pacific). Measurements were made of spire height (∂x), maximum diameter (∂y), the tangent angles of t...
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ftccsdartic:oai:HAL:hal-00164930v1 2023-05-15T18:01:12+02:00 Morphological variability of Globorotalia menardii (planktonic foraminifera) in two DSDP cores from the Caribbean Sea and the Eastern Equatorial Pacific Knappertsbusch, Michael Natural History Museum Basel (NHMB) Natural History Museum Basel 2007-07-02 https://hal.archives-ouvertes.fr/hal-00164930 https://hal.archives-ouvertes.fr/hal-00164930/document https://hal.archives-ouvertes.fr/hal-00164930/file/CG2007_A04.pdf en eng HAL CCSD Carnets de Geologie hal-00164930 https://hal.archives-ouvertes.fr/hal-00164930 https://hal.archives-ouvertes.fr/hal-00164930/document https://hal.archives-ouvertes.fr/hal-00164930/file/CG2007_A04.pdf info:eu-repo/semantics/OpenAccess ISSN: 1765-2553 EISSN: 1634-0744 Carnets de Geologie https://hal.archives-ouvertes.fr/hal-00164930 Carnets de Geologie, Carnets de Geologie, 2007, CG2007 (A04), pp.1-34 Globorotalia menardii Neogene evolution Isthmus of Panama morphometrics [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology info:eu-repo/semantics/article Journal articles 2007 ftccsdartic 2020-12-26T17:33:00Z International audience Variability in the test of Globorotalia menardii during the past 8 million years has been investigated at DSDP Site 502A (Caribbean Sea) and DSDP Site 503A (Eastern Equatorial Pacific). Measurements were made of spire height (∂x), maximum diameter (∂y), the tangent angles of the upper and lower peripheral keels (Φ1, Φ2, respectively), the number of chambers in the final whorl, and the area of the silhouette in keel view. Four morphotypes alpha, beta, gamma, and delta were distinguished. Morphotype alpha was found in strata ranging in age from the Late Miocene through the Holocene. It shows a continuous increase in ∂x and ∂y until the Late Pleistocene. During and after the final closure of the ancient Central American Seaway (between 2.4 Ma and 1.8 Ma) there was a rapid increase in the area of the test in keel view. At the Caribbean Sea site, morphotype beta evolved during the past 0.22 Ma. It is less inflated than alpha and has a more delicate test. In the morphospace of ∂x vs. ∂y, morphotypes alpha and beta can be distinguished by a separation line ∂y = 3.2 * ∂x - 160 (∂x and ∂y in µm). Plots of morphotype alpha are below that line, those of beta are above it. Morphotype alpha is taken to be Globorotalia menardii menardii Parker, Jones & Brady (1865) and includes G. menardii 'A' Bolli (1970). Morphotype beta is identified as G. menardii cultrata (d'Orbigny). Morphotypes gamma and delta are extinct Upper Miocene to Pliocene forms which evolved from morphotype alpha. They have a narrower Φ1 angle and more chambers (≥7) than morphotype alpha commonly with 5 to 6 chambers (7 in transitional forms). In contemporaneous samples morphotype delta can be distinguished from gamma by a smaller value of Φ1 and 8 or more chambers in the final whorl. Morphotype gamma is taken to be G. limbata (Fornasini, 1902) and includes the junior synonym G. menardii 'B' Bolli (1970). Morphotype delta is G. multicamerata Cushman & Jarvis (1930). With the exception of the Late Pleistocene development of G. ... Article in Journal/Newspaper Planktonic foraminifera Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Pacific |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
Globorotalia menardii Neogene evolution Isthmus of Panama morphometrics [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology |
spellingShingle |
Globorotalia menardii Neogene evolution Isthmus of Panama morphometrics [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology Knappertsbusch, Michael Morphological variability of Globorotalia menardii (planktonic foraminifera) in two DSDP cores from the Caribbean Sea and the Eastern Equatorial Pacific |
topic_facet |
Globorotalia menardii Neogene evolution Isthmus of Panama morphometrics [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology |
description |
International audience Variability in the test of Globorotalia menardii during the past 8 million years has been investigated at DSDP Site 502A (Caribbean Sea) and DSDP Site 503A (Eastern Equatorial Pacific). Measurements were made of spire height (∂x), maximum diameter (∂y), the tangent angles of the upper and lower peripheral keels (Φ1, Φ2, respectively), the number of chambers in the final whorl, and the area of the silhouette in keel view. Four morphotypes alpha, beta, gamma, and delta were distinguished. Morphotype alpha was found in strata ranging in age from the Late Miocene through the Holocene. It shows a continuous increase in ∂x and ∂y until the Late Pleistocene. During and after the final closure of the ancient Central American Seaway (between 2.4 Ma and 1.8 Ma) there was a rapid increase in the area of the test in keel view. At the Caribbean Sea site, morphotype beta evolved during the past 0.22 Ma. It is less inflated than alpha and has a more delicate test. In the morphospace of ∂x vs. ∂y, morphotypes alpha and beta can be distinguished by a separation line ∂y = 3.2 * ∂x - 160 (∂x and ∂y in µm). Plots of morphotype alpha are below that line, those of beta are above it. Morphotype alpha is taken to be Globorotalia menardii menardii Parker, Jones & Brady (1865) and includes G. menardii 'A' Bolli (1970). Morphotype beta is identified as G. menardii cultrata (d'Orbigny). Morphotypes gamma and delta are extinct Upper Miocene to Pliocene forms which evolved from morphotype alpha. They have a narrower Φ1 angle and more chambers (≥7) than morphotype alpha commonly with 5 to 6 chambers (7 in transitional forms). In contemporaneous samples morphotype delta can be distinguished from gamma by a smaller value of Φ1 and 8 or more chambers in the final whorl. Morphotype gamma is taken to be G. limbata (Fornasini, 1902) and includes the junior synonym G. menardii 'B' Bolli (1970). Morphotype delta is G. multicamerata Cushman & Jarvis (1930). With the exception of the Late Pleistocene development of G. ... |
author2 |
Natural History Museum Basel (NHMB) Natural History Museum Basel |
format |
Article in Journal/Newspaper |
author |
Knappertsbusch, Michael |
author_facet |
Knappertsbusch, Michael |
author_sort |
Knappertsbusch, Michael |
title |
Morphological variability of Globorotalia menardii (planktonic foraminifera) in two DSDP cores from the Caribbean Sea and the Eastern Equatorial Pacific |
title_short |
Morphological variability of Globorotalia menardii (planktonic foraminifera) in two DSDP cores from the Caribbean Sea and the Eastern Equatorial Pacific |
title_full |
Morphological variability of Globorotalia menardii (planktonic foraminifera) in two DSDP cores from the Caribbean Sea and the Eastern Equatorial Pacific |
title_fullStr |
Morphological variability of Globorotalia menardii (planktonic foraminifera) in two DSDP cores from the Caribbean Sea and the Eastern Equatorial Pacific |
title_full_unstemmed |
Morphological variability of Globorotalia menardii (planktonic foraminifera) in two DSDP cores from the Caribbean Sea and the Eastern Equatorial Pacific |
title_sort |
morphological variability of globorotalia menardii (planktonic foraminifera) in two dsdp cores from the caribbean sea and the eastern equatorial pacific |
publisher |
HAL CCSD |
publishDate |
2007 |
url |
https://hal.archives-ouvertes.fr/hal-00164930 https://hal.archives-ouvertes.fr/hal-00164930/document https://hal.archives-ouvertes.fr/hal-00164930/file/CG2007_A04.pdf |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Planktonic foraminifera |
genre_facet |
Planktonic foraminifera |
op_source |
ISSN: 1765-2553 EISSN: 1634-0744 Carnets de Geologie https://hal.archives-ouvertes.fr/hal-00164930 Carnets de Geologie, Carnets de Geologie, 2007, CG2007 (A04), pp.1-34 |
op_relation |
hal-00164930 https://hal.archives-ouvertes.fr/hal-00164930 https://hal.archives-ouvertes.fr/hal-00164930/document https://hal.archives-ouvertes.fr/hal-00164930/file/CG2007_A04.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1766170568475803648 |