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2002-2003
Science Planning Summary
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Geology & Geophysics
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Dr. Scott Borg
Program Manager
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GO-152-O
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NSF/OPP
00-88143
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Station:
RV/IB Nathaniel B Palmer
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RPSC POC:
Jim Holik
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Research Site(s):
RV/IB NBP
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Antarctic cretaceous-cenozoic climate, glaciation, and tectonics: Site surveys for drilling from the edge of the Ross Ice Shelf
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Deploying Team Members:
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Louis R Bartek
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Tom M Carpenter
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Emily W Crawford
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Robert C Decesari
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John Diebold
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Bruce P Luyendyk
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Jared P Marske
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Zenon R Mateo
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Robin S Matoza
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Heather N Ramsey
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Joan Rosenburg
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Christopher C Sorlien
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Kathryn D Sowder
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Michelle E Thibault
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Karen N Vasko
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Jeffrey D Warren
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Brandon J Wood
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Research Objectives:
Many of the outstanding problems concerning the evolution of the East and West Antarctic Ice Sheets, antarctic climate, global sea level, and the tectonic history of the West Antarctic Rift System will be solved by drilling into the seafloor of the Ross Sea.
Climate data for Cretaceous and Early Cenozoic time are lacking for this sector of Antarctica. Climate questions include, Was there any ice in Late Cretaceous time? What was the antarctic climate during the Paleocene-Eocene global warming? When was the Cenozoic onset of antarctic glaciation? When did glaciers reach the coast and when did they advance out onto the margin? Was the Ross Sea shelf non-marine in Late Cretaceous time? When did it become marine?
Tectonic questions include, What was the timing of the Cretaceous extension in the Ross Sea rift? Where was it located? What is the basement composition and structure? Where are the time and space limits of the effects of Adare Trough spreading?
This group will conduct sites surveys for drilling from the Ross Ice Shelf into the seafloor beneath it. Another drilling objective is to sample and date the sedimentary section bounding the mapped RSU6 unconformity in the Eastern Basin and Central Trough to resolve questions about its age and regional extent. Deep Sea Drilling Project Leg 28 completed sampling at four drill sites in the early 1970's but had low recovery and did not sample the Early Cenozoic. Other drilling has been restricted to the McMurdo Sound area of the western Ross Sea and results can be correlated into the Victoria Land Basin but not eastward across basement highs. Further, Early Cenozoic and Cretaceous rocks have not been sampled.
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Field Season Overview:
The researchers will collect swath bathymetry, gravity, magnetic, sub-bottom profile, high-resolution and deep-penetration seismic profiling data. Sediment cores will be collected to obtain samples for geotechnical properties, to study sub-ice shelf modern sedimentary processes, and to study locations where deeper strata is exposed.
The survey will include long profiles and detailed grids over potential Ocean Drilling Project (ODP) drill sites. Survey lines will be tied to existing geophysical profiles and deep sea drilling project's (DSDP) 270 sites.
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