Mineralogy and sedimentology of the Pleistocene to Holocene on the leeward margin of Great Bahama Bank

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doi: 10.2973/odp.proc.sr.166.114.2000
Author(s): Rendle, Rebecca H.; Reijmer, John J. G.; Kroon, Dick; Henderson, Gideon M.
Ocean Drilling Program, Leg 166, Shipboard Scientific Party, College Station, TX
Author Affiliation(s): Primary:
GEOMAR Forschungszentrum für Marine Geowissenschaften, Kiel, Federal Republic of Germany
Ocean Drilling Program, United States
Geological Survey of Japan, Japan
Johann Wolfgang Goethe-Universität, Federal Republic of Germany
University of South Carolina, United States
University of Hawaii, United States
CNRS-Centre de Sédimentologie et de Géochimie de la Surface, France
University of Bourgogne, France
University of Michigan, United States
Rice University, United States
University of Sydney, Australia
Lamont-Doherty Earth Observatory, United States
Vrije Universiteit, Netherlands
Nova University, United States
University of Edinburgh, United Kingdom
ETH-Zentrum, Switzerland
University of East Anglia, United Kingdom
University of Houston, United States
Christian-Albrechts-Universität zu Kiel, Federal Republic of Germany
Akita University, Japan
University of Copenhagen, Denmark
Leicester University, United Kingdom
University of Maine, United States
Oxford University, United Kingdom
Volume Title: Proceedings of the Ocean Drilling Program, scientific results, Bahamas Transect; covering Leg 166 of the cruises of the drilling vessel JOIDES Resolution, San Juan, Puerto Rico, to Balboa Harbor, Panama, sites 1003-1009, 17 February-10 April 1996
Volume Author(s): Swart, Peter K.; Eberli, Gregor P.; Malone, Mitchell J.; Anselmetti, Flavio S.; Arai, Kohsaku; Bernet, Karin H.; Betzler, Christian; Christensen, Beth A.; De Carlo, Eric Heinen; Déjardin, Pascale M.; Emmanuel, Laurent; Frank, Tracy D.; Haddad, Geoffrey A.; Isern, Alexandra R.; Katz, Miriam E.; Kenter, Jeroen A. M.; Kramer, Philip A.; Kroon, Dick; McKenzie, Judith A.; McNeill, Donald F.; Montgomery, Paul; Nagihara, Seiichi; Pirmez, Carlos; Reijmer, John J. G.; Sato, Tokiyuki; Schovsbo, Niels H.; Williams, Trevor; Wright, James D.; Lowe, Ginny
Source: Proceedings of the Ocean Drilling Program, scientific results, Bahamas Transect; covering Leg 166 of the cruises of the drilling vessel JOIDES Resolution, San Juan, Puerto Rico, to Balboa Harbor, Panama, sites 1003-1009, 17 February-10 April 1996, Peter K. Swart, Gregor P. Eberli, Mitchell J. Malone, Flavio S. Anselmetti, Kohsaku Arai, Karin H. Bernet, Christian Betzler, Beth A. Christensen, Eric Heinen De Carlo, Pascale M. Déjardin, Laurent Emmanuel, Tracy D. Frank, Geoffrey A. Haddad, Alexandra R. Isern, Miriam E. Katz, Jeroen A. M. Kenter, Philip A. Kramer, Dick Kroon, Judith A. McKenzie, Donald F. McNeill, Paul Montgomery, Seiichi Nagihara, Carlos Pirmez, John J. G. Reijmer, Tokiyuki Sato, Niels H. Schovsbo, Trevor Williams, James D. Wright and Ginny Lowe; Ocean Drilling Program, Leg 166, Shipboard Scientific Party, College Station, TX. Proceedings of the Ocean Drilling Program, Scientific Results, Vol.166, p.61-76. Publisher: Texas A & M University, Ocean Drilling Program, College Station, TX, United States. ISSN: 0884-5891
Note: In English. 67 refs.CD-ROM format, ISSN 1096-2514; WWW format, ISSN 1096-7451; all chapters are also available on the included CD-ROM and on the Web in PDF format; illus., incl. sketch map
Summary: The mineralogy of periplatform carbonates is well documented in the literature. However, little is written about the grain-size properties for carbonate rocks. This fundamental property forms a controlling factor for other derived physical properties such as bulk density, porosity, and permeability. Thus, grain-size distribution and sorting might also steer fluid flow through the sediments, and combined with the mineralogy, might affect the development of the initial diagenetic pattern, which is significant in the interpretation of ancient depositional environments and transport conditions. This study, therefore, documents grain-size variations in conjunction with carbonate mineralogy for periplatform oozes of Sites 1003 (mid-slope) and 1006 (basin) on the leeward side of the Great Bahama Bank. The results reveal some distinct differences between glacial periods (glacials) and interglacial periods (interglacials) through both time and space. The δ18O and aragonite stratigraphy shows an almost complete sedimentary record for Site 1006, which is supported in the upper section by the U/Th dates assigned to interglacial Stages 1, 5, 9, and 11. However, Site 1003 stratigraphy indicates that large hiatuses exist within the sedimentary record and that there is evidence for diagenetic overprinting. This interpretation is further supported by the U/Th dates provided. Glacials are represented by sediment dominated by high-Mg calcite (HMC) and low-Mg calcite (LMC). The HMC probably originates from erosion of magnesium-calcite micrite cements formed in the upper slope deposits or HMC cements formed during early diagenesis. Detrital dolomite is also present at the distal site (Site 1006). Quartz also occurs preferentially during these periods. Although the grain-size distribution shows dominance by silts and clays (i.e., fine fraction [<63 µm]) the percentage of the coarse fraction (>63 µm) increases markedly during glacials. The latter fraction shows an increased dominance by the coarse (500-1000 µm) to very coarse (>1000 µm) sand-size fractions. Interglacials, in contrast, are dominated by aragonite, mainly in the form of fine-grained, bank-top -derived aragonite needles. This is supported by the grain-size distribution, which again shows dominance by silts and clays (<63 µm). Dolomite is present at Site 1003, originating from early diagenesis. The coarse fraction (>63 µm) is dominated by the very fine (63-125 µm) to medium (250-500 µm) sand-sized particles. Therefore, the fine-grained interglacial deposits will have a low diagenetic potential because of restricted fluid flow and low permeability, whereas the glacials will show the reverse pattern where the coarse-grained sediment facilitates early diagenesis. The diagenetic potential of the sediment on the leeward side of the Great Bahama Bank, therefore, varies through both time (between glacial and interglacials) and space (decreasing in potential with increasing distance from the platform). The composition of the coarse grains (63 µm) exported from the platform during glacial and interglacials forms the key link in understanding the mineralogy and grain-size data, and thus is the main topic of work in progress.
Year of Publication: 2000
Research Program: ODP Ocean Drilling Program
Key Words: 03 Geochronology; 24 Surficial Geology, Quaternary Geology; Absolute age; Aragonite; Atlantic Ocean; Bulk density; Carbonates; Caribbean Sea; Cenozoic; Dates; Depositional environment; Diagenesis; Geochemistry; Glacial environment; Grain size; Great Bahama Bank; Holocene; Interglacial environment; Isotope ratios; Isotopes; Leg 166; Marine sediments; Mineral composition; North Atlantic; O-18/O-16; ODP Site 1003; ODP Site 1006; Ocean Drilling Program; Oxygen; Paleoclimatology; Physical properties; Pleistocene; Porosity; Quaternary; Reconstruction; Sediments; Size distribution; Stable isotopes; Th/U; Variations
Coordinates: N241000 N245000 W0790000 W0795000
N243245 N243245 W0791539 W0791539
Record ID: 2001002885
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