The record of Neogene sea-level changes in the prograding carbonates along the Bahamas Transect; Leg 166 synthesis

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doi: 10.2973/odp.proc.sr.166.128.2000
Author(s): Eberli, Gregor P.
Ocean Drilling Program, Leg 166, Shipboard Scientific Party, College Station, TX
Author Affiliation(s): Primary:
Rosenstiel School of Marine and Atmospheric Science, Comparative Sedimentology Laboratory, Miami, FL, United States
Other:
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
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.167-177. Publisher: Texas A & M University, Ocean Drilling Program, College Station, TX, United States. ISSN: 0884-5891
Note: In English. 74 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. 1 table, sects.
Summary: The Bahamas Transect was designed to assess the response of the carbonate depositional system to sea-level changes and to evaluate the relationship between the sedimentary and oxygen isotope records of Neogene sea-level changes in order to establish a causal link between glacio-eustasy and the stratigraphic pattern. In addition, the timing of unconformity-bounded sequences and the question of chronostratigraphic significance of seismic sequence boundaries were of special interest. Cores from seven sites drilled during Leg 166 along the western Great Bahama Bank retrieved the sedimentary record and the timing of high- and low-frequency sea-level changes throughout the Neogene. Facies successions within the cores contain indications of sea-level changes on two different scales. First, there are high-frequency alternations between meter-thick layers with platform-derived material and thin layers with more pelagic sediments. Carbonate-rich intervals are interpreted to reflect periods of high sea level, whereas the thin intervals correspond to times of increased pelagic and siliciclastic input during sea-level lowstands. The duration of these alternations (20-40 k.y.) correlates with orbitally induced high-frequency climate and sea-level changes. Second, longer term sea-level changes with a duration of 0.5-2.0 m.y. are also recorded in slope deposits along the Great Bahama Bank. Alternating high (up to 20 cm/k.y.) and low (<2 cm/k.y.) sedimentation rates record a long-term pattern of bank flooding with concomitant shedding to the slope as well as periods of bank exposure with reduced shallow-water carbonate production, upper slope erosion, and largely pelagic sedimentation in the basin. The longer term changes coincide with progradation pulses that are imaged on the seismic data as depositional sequences. The internal facies architecture of these carbonate depositional sequences displays five major elements. In the undathem, or the platform top, the sediments are arranged in shallow-water packages separated by exposure horizons. Thick bulges of the prograding pulses are characterized by fine-grained platform-derived material that accumulates on the upper slope. The middle to lower slope has a variable facies assemblage consisting of periplatform, pelagic, and redeposited carbonates. Small-scale channeling and lobes of turbidites produce irregular depositional surfaces. At the toe-of-slope, redeposited carbonates accumulate during both sea-level highstands and lowstands. These carbonate turbidite series are arranged in mounded lobes with feeder channels. The distal portion of the sequences is dominated by cyclic marl/limestone alternations with few turbidites. The ages of the 17 observed Neogene seismic sequence boundaries yielded an excellent correlation between sites, documenting the age consistency of the sequence boundaries and chronostratigraphic significance of the seismic reflections. The ages of the sequences along the Bahamas Transect provide a data set that, in conjunction with data sets from other margins, will eventually solve the question about global synchronous longer term sea-level changes. A comparison between the sedimentary and isotope records reveals a discrepancy in the frequency of sea-level changes. Oxygen isotopes record sea-level changes at an obliquity frequency, whereas resistivity and gamma-ray values record sea-level changes dominated by orbital precession. These precessional cycles are packaged into longer term cycles of eccentricity (100, 400, and 2000 k.y.).
Year of Publication: 2000
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Biostratigraphy; Caribbean Sea; Cenozoic; Chronostratigraphy; Climate change; Climate forcing; Correlation; Eccentricity; Foraminifera; Geochemistry; Invertebrata; Isotope ratios; Isotopes; Leg 166; Lithofacies; Marine sediments; Microfossils; Neogene; North Atlantic; O-18/O-16; Ocean Drilling Program; Orbital forcing; Oxygen; Paleoclimatology; Precession; Protista; Sea-level changes; Sediments; Sequence stratigraphy; Stable isotopes; Tertiary; Turbidite
Coordinates: N233000 N243500 W0790300 W0792800
Record ID: 2001002895
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