Taphonomy on the continental shelf and slope: two-year trends – Gulf of Mexico and Bahamas

Title:
Taphonomy on the continental shelf and slope: two-year trends – Gulf of Mexico and Bahamas
Authors:
Powell, Eric N.; Parsons-Hubbard, Karla; Callender, W. Russell; Staff, George M.; Rowe, Gilbert T.; Brett, Carlton E.; Walker, Sally E.; Raymond, Anne L.; Carlson, Donna D.; White, Suzanne; Heise, Elizabeth A.
Abstract:
The Shelf and Slope Experimental Taphonomy Initiative was established to measure taphonomic rates in a range of continental shelf and slope environments of deposition (EODs) over a multiyear period. We deployed experiments on the forereef slope off Lee Stocking Island, Bahamas, and on the continental shelf and slope of the Gulf of Mexico for 2 yr in 18 distinctive EODs at depths from 15 to 530 m. Overall, most shells deployed at most sites had relatively minor changes in shell condition. Most EODs generated relatively similar taphonomic signatures. A few sites did produce taphonomic signatures clearly distinguishable from the central group and these sites were characterized by one or more of the following: high rates of oxidation of reduced compounds, presence in the photic zone, and significant burial and exhumation events. Thus, unique taphonomic signatures are created by unique combinations of environmental conditions that include variables associated with regional gradients, such as depth and light, and variables associated with edaphic processes, such as the seepage of brine or petroleum or the resuspension and redeposition of sediment. Most sites, however, showed similar taphonomic signatures, despite the variety of EOD characteristics present, suggesting that insufficient time had elapsed over 2 yr to generate a more diverse array of taphonomic signatures. Discoloration and dissolution were by far the dominant processes over the 2-yr deployment period. Periostracum breakdown, loss of shell weight, and chipping and breakage was less noticeable. EODs were chosen based on the expectation that the process of burial and the influence of depth and sediment type should play the greatest roles in determining between-EOD differences in taphonomic signature. EOD-specific edaphic factors often overrode the influence of geographic-scale environmental gradients. Taphonomic alteration was greater on hardgrounds and in brine-exposed sites than on terrigenous muds. Dissolution was less effective at sites where burial was greatest. Discoloration occurred most rapidly at shallower sites and on hardgrounds. Water depth was less influential in determining taphonomic signature than burial state or sediment type. The limited influence of water depth is likely due to the presence of shallow sites that, for one reason or another, were protected from certain taphonomic processes and deeper sites that were characterized by unusually strong taphonomic signals.
Citation:
Powell, Eric N., Karla M. Parsons-Hubbard, W. Russell Callender, George M. Staff, Gilbert T. Rowe, Carlton E. Brett, Sally E. Walker et al. 2002. "Taphonomy on the continental shelf and slope: two-year trends–Gulf of Mexico and Bahamas." Palaeogeography, Palaeoclimatology, Palaeoecology 184(1-2): 1-35.
Publisher:
Elsevier
DATE ISSUED:
2002-08
Department:
Geology
Type:
Article
PUBLISHED VERSION:
10.1016/S0031-0182(01)00457-6
Additional Links:
http://linkinghub.elsevier.com/retrieve/pii/S0031018201004576
PERMANENT LINK:
http://hdl.handle.net/11282/595718

Full metadata record

DC FieldValue Language
dc.contributor.authorPowell, Eric N.en
dc.contributor.authorParsons-Hubbard, Karlaen
dc.contributor.authorCallender, W. Russellen
dc.contributor.authorStaff, George M.en
dc.contributor.authorRowe, Gilbert T.en
dc.contributor.authorBrett, Carlton E.en
dc.contributor.authorWalker, Sally E.en
dc.contributor.authorRaymond, Anne L.en
dc.contributor.authorCarlson, Donna D.en
dc.contributor.authorWhite, Suzanneen
dc.contributor.authorHeise, Elizabeth A.en
dc.date.accessioned2016-02-05T14:45:23Zen
dc.date.available2016-02-05T14:45:23Zen
dc.date.issued2002-08en
dc.identifier.citationPowell, Eric N., Karla M. Parsons-Hubbard, W. Russell Callender, George M. Staff, Gilbert T. Rowe, Carlton E. Brett, Sally E. Walker et al. 2002. "Taphonomy on the continental shelf and slope: two-year trends–Gulf of Mexico and Bahamas." Palaeogeography, Palaeoclimatology, Palaeoecology 184(1-2): 1-35.en
dc.identifier.issn003-10182en
dc.identifier.urihttp://hdl.handle.net/11282/595718en
dc.description.abstractThe Shelf and Slope Experimental Taphonomy Initiative was established to measure taphonomic rates in a range of continental shelf and slope environments of deposition (EODs) over a multiyear period. We deployed experiments on the forereef slope off Lee Stocking Island, Bahamas, and on the continental shelf and slope of the Gulf of Mexico for 2 yr in 18 distinctive EODs at depths from 15 to 530 m. Overall, most shells deployed at most sites had relatively minor changes in shell condition. Most EODs generated relatively similar taphonomic signatures. A few sites did produce taphonomic signatures clearly distinguishable from the central group and these sites were characterized by one or more of the following: high rates of oxidation of reduced compounds, presence in the photic zone, and significant burial and exhumation events. Thus, unique taphonomic signatures are created by unique combinations of environmental conditions that include variables associated with regional gradients, such as depth and light, and variables associated with edaphic processes, such as the seepage of brine or petroleum or the resuspension and redeposition of sediment. Most sites, however, showed similar taphonomic signatures, despite the variety of EOD characteristics present, suggesting that insufficient time had elapsed over 2 yr to generate a more diverse array of taphonomic signatures. Discoloration and dissolution were by far the dominant processes over the 2-yr deployment period. Periostracum breakdown, loss of shell weight, and chipping and breakage was less noticeable. EODs were chosen based on the expectation that the process of burial and the influence of depth and sediment type should play the greatest roles in determining between-EOD differences in taphonomic signature. EOD-specific edaphic factors often overrode the influence of geographic-scale environmental gradients. Taphonomic alteration was greater on hardgrounds and in brine-exposed sites than on terrigenous muds. Dissolution was less effective at sites where burial was greatest. Discoloration occurred most rapidly at shallower sites and on hardgrounds. Water depth was less influential in determining taphonomic signature than burial state or sediment type. The limited influence of water depth is likely due to the presence of shallow sites that, for one reason or another, were protected from certain taphonomic processes and deeper sites that were characterized by unusually strong taphonomic signals.en
dc.language.isoen_USen
dc.publisherElsevieren
dc.identifier.doi10.1016/S0031-0182(01)00457-6en
dc.relation.urlhttp://linkinghub.elsevier.com/retrieve/pii/S0031018201004576en
dc.subject.departmentGeologyen_US
dc.titleTaphonomy on the continental shelf and slope: two-year trends – Gulf of Mexico and Bahamasen_US
dc.typeArticleen
dc.identifier.journalPalaeogeography, Palaeoclimatology, Palaeoecologyen
dc.subject.keywordTaphonomyen_US
dc.subject.keywordPreservationen_US
dc.subject.keywordEnvironment of depositionen_US
dc.subject.keywordDissolutionen_US
dc.subject.keywordShell carbonateen_US
dc.subject.keywordBurialen_US
dc.identifier.volume184en_US
dc.identifier.issue1-2en_US
dc.identifier.startpage1en_US
dc.rightsArchived with thanks to Palaeogeography, Palaeoclimatology, Palaeoecologyen
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