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A study of Mesozoic (Early Cretaceous) radiolaria from DSDP Hole 534A

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dc.contributor.advisor Ling, Hsin-Yi, 1930- en_US Niebuhr, Randy R. en_US 2016-04-22T19:50:35Z 2016-04-22T19:50:35Z 1986
dc.description Bibliography: pages [59]-65. en_US
dc.description.abstract Continuous coring was attempted at Site 534 during leg 76 of the Deep Sea Drilling Project, in order to recover Middle and Upper Jurassic sediments and basalt basement rocks from the Blake-Bahama Basin in the western North Atlantic. Geographically, Site 534 is located between Florida and Bermuda at 28° 20.6' N, 75° 22.8' W and at a water depth of 4,976 m. The occurrence of Mesozoic radiolarians reported by the shipboard scientists constituted the oldest radiolarian- bearing submarine deposits yet drilled in the Atlantic Ocean. The main objectives of my research were: (1) to examine the radiolarian taxonomy and biostratigraphic distribution; and (2) to compare their geological occurrence with previously established biostratigraphic zones. It was a surprise, therefore, to find that only 13 out of 45 samples examined yielded radiolarians of any significant abundance, and all are Early Cretaceous in age. Core 51 appears to belong to the Eucyrtis tenuis zone of Barremian age, first recognized by Riedel and Sanfilippo in 1974, and Gores 69 through 82 to the Sethocapsa trachyostraca zone of Valanginian (Neocomian) age, first reported by Foreman in 1975. The absence of Dibolachras tytthopora, which defines the top of the Sethocapsa trachyostraca zone, places Cores 70 through 82 in the lower portion of that zone. Radiolarian assemblages of correlative age have been reported from several outcrop sections from Japan, thus providing the basis for future paleoceanographic consideration. The majority of radiolarians recovered from Hole 534A have had their siliceous skeletons replaced by pyrite. The replacement of silica by pyrite probably indicates a reducing environment during the early diagenesis of the sediments. A similar phenomenon was observed from Early Cretaceous sediments recovered during legs 1 and 44 in the same area. en_US
dc.format.extent ix, 85 pages en_US
dc.language.iso eng en_US
dc.publisher Northern Illinois University en_US
dc.rights NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors. en_US
dc.subject.lcsh Paleontology--Mesozoic en_US
dc.subject.lcsh Paleontology--North Atlantic Ocean en_US
dc.subject.lcsh Radiolaria, Fossil en_US
dc.title A study of Mesozoic (Early Cretaceous) radiolaria from DSDP Hole 534A en_US
dc.type.genre Dissertation/Thesis en_US
dc.type Text en_US
dc.contributor.department Department of Geology en_US M.S. (Master of Science) en_US

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