Nederbragt, Alexandra J. and Thurow, Juergen (2002): Sediment color variation and annual accumulation rates in laminated Holocene sediments, Site 1098, Palmer Deep

Leg/Site/Hole:
ODP 178
ODP 178 1098
Identifier:
2003-022398
georefid

10.2973/odp.proc.sr.178.209.2001
doi

Creator:
Nederbragt, Alexandra J.
University College London, Department of Geological Sciences, London, United Kingdom
author

Thurow, Juergen
Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Italy
author

Identification:
Sediment color variation and annual accumulation rates in laminated Holocene sediments, Site 1098, Palmer Deep
2002
In: Baker, Peter F. (editor), Camerlenghi, Angelo (editor), Acton, Gary D. (editor), Brachfeld, Stefanie A., Cowan, Ellen A., Daniels, James, Domack, Eugene W., Escutia, Carlota, Evans, Andrew J., Eyles, Nicholas, Guyodo, Yohan J. B., Hatfield, Kate L., Iorio, Marina, Iwai, Masao, Kyte, Frank T., Lauer, Christine, Maldonado, Andres, Moerz, Tobias, Osterman, Lisa E., Pudsey, Carol J., Schuffert, Jeffrey D., Sjunneskog, Charlotte M., Weinheimer, Amy L., Williams, Trevor, Winter, Diane M., Wolf-Welling, Thomas C. W., Ramsay, Anthony T. S. (editor), Proceedings of the Ocean Drilling Program, scientific results, Antarctic glacial history and sea-level change; covering Leg 178 of the cruises of the drilling vessel JOIDES Resolution; Punta Arenas, Chile, to Cape Town, South Africa; sites 1095-1103; 5 February-9 April 1998
Texas A&M University, Ocean Drilling Program, College Station, TX, United States
178
Continuous sediment color records with a resolution of one measurement per millimeter were generated for Site 1098 (Palmer Deep, Antarctic Peninsula) from digital images of the core surfaces to test if the laminated intervals at this site will allow for analysis of high-frequency climate variability in the Circum-Antarctic. Long-term variation in color values correlates with gamma-ray attenuation bulk density. Darker colors are found in laminated intervals with lower bulk density, high biogenic silica, and high total organic carbon content. Darker color values result from the addition of dark laminae to background sediments that show little variation in color. The thicknesses of dark and light laminae were measured in the top 25 meters composite depth to determine the temporal resolution of the laminae. The alternation between dark, biogenic-rich laminae and background sediment essentially represents an annual cycle, but the sediment is not consistently varved. The modal thickness of light laminae is close to the long-term average annual accumulation rate, and results indicate that approximately half of the dark/light couplets in distinctly laminated intervals represent a single year. Missing biogenic laminae are interpreted to represent reduced primary productivity during cold years with delayed breakup of the sea-ice cover.
Coverage:Geographic coordinates:
North:-64.5143
West:-64.1228East: -64.1228
South:-64.5143

Quaternary geology; annual variations; Antarctic Ocean; biogenic processes; carbon; Cenozoic; color; cores; framework silicates; gamma-ray methods; geochemistry; Holocene; ice; laminations; Leg 178; marine sediments; Ocean Drilling Program; ODP Site 1098; opal; organic carbon; paleo-oceanography; paleoclimatology; Palmer Deep; planar bedding structures; Quaternary; reconstruction; sea ice; sedimentary structures; sedimentation; sedimentation rates; sediments; silica minerals; silicates; thickness; variations;

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