The pelagic ooze-chalk-limestone transition and its implications for marine stratigraphy

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doi: 10.1002/9781444304855.ch6
Author(s): Schlanger, Seymour O.; Douglas, Robert G.
Author Affiliation(s): Primary:
Univ. Calif., Dep. Earth Sci., Riverside, Calif., United States
Volume Title: Special Publication of the International Association of Sedimentologists
Source: Special Publication of the International Association of Sedimentologists, 1, p.117-148. Publisher: Blackwell, Oxford, International. ISSN: 0141-3600. ISBN: 978-1-444-30485-5 CODEN: SPISDS
Note: In English. Benthonic and planktonic foraminifera and nannofossils from the Pacific Ocean, Magellan Rise, from the Cretaceous to the Quaternary; illus. incl. sketch map, tables, charts
Summary: Recovery of long sequences of cores, at Deep Sea Drilling Project sites, from Recent to Upper Jurassic pelagic ooze-chalk-limestone sections has shown that in general lithification increases with age and depth of burial. However, the relationship between degree of lithification and depth of burial in any core is not a direct one. A diagenetic model is presented that accounts for the major reduction in porosity and foraminiferal content with depth and age and the development of cement and overgrowth on those microfossils which are not dissolved. The primary diagenetic mechanism functions through the solution of less stable, very small, calcite crystals such as make up small coccolith elements and the walls of Foraminifera, and reprecipitation of calcite upon large crystals such as make up discoasters and large coccoliths. The concomitant decrease in surface energy probably provides the driving force for this process. The variation in the degree of cementation of ooze-chalk-limestone sequences when plotted as a function of depth is ascribed to initial variations in the diagenetic potential of the sediments as they are buried. The diagenetic potential of a sediment is defined as the length of the diagenetic pathway the sediment has left to traverse before it becomes a crystalline aggregate. In marine acoustistratigraphy, the concept of the diagenetic potential relates seismic reflectors to original intrastratal differences in microfossil content. Seismic reflectors in this context therefore record palaeo-oceanographic events such as changes in the calcite compensation depth, surface water temperature, plankton productivity and glacio-eustatic sea level. Abstract Copyright (1974), The International Association of Sedimentologists.
Year of Publication: 1974
Research Program: DSDP Deep Sea Drilling Project
Key Words: 07 Marine Geology and Oceanography; Acoustistratigraphy; Algae; Calcite; Carbonate compensation depth; Carbonate rocks; Carbonates; Cenozoic; Chalk; Changes of level; Clastic sediments; Coccolithophoraceae; Cores; Cretaceous; Deep Sea Drilling Project; Diagenesis; Discoasteridae; Foraminifera; Geophysical methods; Geophysical surveys; Glacio-eustatic; Invertebrata; Limestone; Lithification; Lysocline; Magellan Rise; Marine; Marine geology; Mesozoic; Microfossils; Models; Nannofossils; Oceanography; Ooze; Pacific Ocean; Plankton; Plantae; Protista; Sedimentary rocks; Sedimentation; Sediments; Seismic methods; Solution; Stratigraphy; Surveys; Temperature; Tertiary; Thallophytes; Transition
Record ID: 1975025993
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.

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