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Upper Paleocene-Lower Eocene Radiolarian Biostratigraphy of the San Francisco de Paula Section, Western Cuba: Regional and Global Comparisons
In response to a growing need to define the Paleocene/Eocene boundary and record the events which immediately preceded and followed it within a 5 my span, the San Francisco de Paula section of western Cuba was evaluated for its potential as a boundary stratotype. Radiolarians, reported in previous s...
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Published in: | Micropaleontology 1999-01, Vol.45, p.57-82 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that cite this one |
Online Access: | Get full text |
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Summary: | In response to a growing need to define the Paleocene/Eocene boundary and record the events which immediately preceded and followed it within a 5 my span, the San Francisco de Paula section of western Cuba was evaluated for its potential as a boundary stratotype. Radiolarians, reported in previous studies by Cuban geologists as a major component of the faunal assemblages in this section, have been recollected and reanalyzed to determine their stratigraphic utility for recognition of the Paleocene/Eocene boundary in Cuba. On the basis of this and other recent microfossil studies of the San Francisco de Paula section, it is now known that the Paleocene/Eocene boundary in this succession is within an unconformity. Its placement herein is based on the highest occurrence of the planktonic foraminifera Morozovella velascoensis (Fernández-Rodríguez et al. 1999, this volume). Radiolarians are present throughout the San Francisco de Paula succession with the exception of a barren interval in the middle of the section and two thin barren intervals near the top and the base. The most diverse radiolarian assemblages are from the shaley mudstones, which contain poorly preserved radiolarians that range from abundant to very rare. Other lithologies contain sparse, poorly preserved assemblages that appear strongly affected by dissolution. Thirty-five lowest and highest occurrences are noted within the section; however, because of poor preservation, several of these datums are higher or lower than expected when compared with the known global ranges of these species. The radiolarians from this study of the San Francisco de Paula section can be assigned to the stratigraphic interval from the upper Paleocene Bekoma campechensis to the lower Eocene Buryella clinata Zones. Species typical of the B. campechensis Zone include Bekoma campechensis, B. demissa, Bekoma spp., Buryella pentadica, B. tetradica, B. foremanae and Lamptonium pennatum. Faunas of the Bekoma bidartensis Zone contain Buryella tetradica, Giraffospyris lata, Phormocyrtis turgida, Podocyrtis (Podocyrtis) papalis, Pterocodon tenellus, Theocorys phyzella, Theocotyle nigriniae, Theocotylissa alpha, T. auctor and Thyrsocyrtis (Thyrsocyrtis) hirsuta. The radiolarian assemblage representing the lower part of the Buryella clinata Zone is similar to that of the Bekoma bidartensis Zone, and also includes the marker species Buryella clinata. Assignment of the upper part of the San Francisco de Paula section to the Buryella |
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ISSN: | 0026-2803 1937-2795 |
DOI: | 10.2307/1486105 |