Morphological variability of Globorotalia menardii in DSDP Sites 68-502 and 68-503 ...
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 (delta x), maximum diameter (delta y), the tangent angles of the upper and...
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| Format: | Article in Journal/Newspaper |
| Language: | English |
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PANGAEA
2007
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| Online Access: | https://dx.doi.org/10.1594/pangaea.863580 https://doi.pangaea.de/10.1594/PANGAEA.863580 |
| Summary: | 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 (delta x), maximum diameter (delta y), the tangent angles of the upper and lower peripheral keels (phi 1, phi 2, 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 delta x and delta 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 delta x vs. ... : Supplement to: Knappertsbusch, Michael W (2007): Morphological variability of Globorotalia menardii (planktonic foraminifera) in two DSDP cores from the Caribbean Sea and the Eastern Equatorial Pacific. Carnets de Geologie, CG2007_A04 ... |
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