(Figure 2) Distribution of planktonic foraminifera in the upper Paleocene of DSDP Hole 93-605


Autoria(s): Nederbragt, Alexandra J; von Hinte, JE
Cobertura

LATITUDE: 38.742200 * LONGITUDE: -72.609200 * DATE/TIME START: 1983-06-11T00:00:00 * DATE/TIME END: 1983-06-11T00:00:00 * MINIMUM DEPTH, sediment/rock: 570.71 m * MAXIMUM DEPTH, sediment/rock: 681.62 m

Data(s)

26/10/1987

Resumo

Good faunal preservation in the upper part of the Planorotatites pseudomenardii Zone at Deep Sea Drilling Project Site 605, northwestern Atlantic, allows a biometric analysis of the upper Paleocene planktonic foraminiferal species Planorotatites pseudomenardii (Belli), a keeled species that probably developed from a middle Paleocene unkeeled Planorotalites form. Multivariate analysis shows a consistent separation of all Planorotatites specimens into two groups, which are differentiated by the presence or absence of a complete keel; other variables are only of minor importance. The keeled group coincides with P. pseudomenardii. We recognize only one unkeeled species, Planorotalites chapmani (Parr), with Planorotalites ehrenbergi (Bolli), Planorotalites imitata (Subbotina), Planorotalites planoconica (Subbotina), Planorotalites troelseni (Loeblich and Tappan), and Planorotalites hausbergensis (Gohrbrandt) as junior synonyms. P. chapmani ranges from the middle Paleocene to at least the top of the upper Paleocene. The morphology of P. pseudomenardii does not change significantly, and although the frequency of Planorotalites is variable, the proportion of P. pseudomenardii to all Planorotalites varies only slightly around 65% in the upper two-thirds of its range at Site 605. However, in the top 1.5 m of its range the proportion of P. pseudomenardii decreases; in the same section, all Planorotalites specimens show a reduction in the size of their tests, suggesting that a temporary change in environmental conditions led to the exit of P. pseudomenardii\ in Magnetozone C24R at Site 605-apparently higher than expected from current standard zonations. Unkeeled Planorotalites, in contrast to R. pseudomenardii, persisted and regained normal size. The entry of P. pseudomenardii at Site 605 cannot be described in the same detail because of low frequencies of Planorotalites specimens and an erratic distribution of P. pseudomenardii in the lower part of its range. Many of the washed residues of the samples from these sediments are dominated by radiolarians, and the poorly preserved foraminiferal faunas may have abundant benthics, indicating carbonate dissolution. The initially low frequencies of P pseudomenardii relative to the unkeeled Planorotalites show a strong negative correlation with the total amount of radiolarians per sample and could be the result of preferential preservation, as well as of the same environmental conditions that caused the abundance of radiolarians.

Formato

text/tab-separated-values, 675 data points

Identificador

https://doi.pangaea.de/10.1594/PANGAEA.250715

doi:10.1594/PANGAEA.250715

Idioma(s)

en

Publicador

PANGAEA

Relação

DSDP (1989): Data from the Deep Sea Drilling Project. Sediment, hard rock and reference files. National Geophysical Data Center, National Environmental Satellite, Data and Information Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce, 1, CD-ROM

Paleontology data base - background and methods (URI: hdl:10013/epic.32352.d001)

Direitos

CC-BY: Creative Commons Attribution 3.0 Unported

Access constraints: unrestricted

Fonte

Supplement to: Nederbragt, Alexandra J; van Hinte, Jan E (1987): Biometric analysis of Planorotalites pseudomenardii (upper Paleocene) at Deep Sea Drilling Project Site 605, Northwestern Atlantic. In: van Hinte, JE; Wise, SW Jr; et al. (eds.), Initial Reports of the Deep Sea Drilling Project, Washington (U.S. Govt. Printing Office), 93, 577-591, doi:10.2973/dsdp.proc.93.114.1987

Palavras-Chave #93-605; Acarinina mckannai; Acarinina soldadoensis; Deep Sea Drilling Project; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP; Foraminifera, benthic; Glomar Challenger; Leg93; Morozovella acuta; Morozovella aequa; Morozovella angulata; Morozovella occlusa; Morozovella pusilla; North Atlantic; ODP sample designation; Planorotalites chapmani; Planorotalites pseudomenardii; Radiolarians abundance; Sample code/label; Subbotina primitiva; Subbotina triloculinoides; Subbotina velascoensis
Tipo

Dataset