Integrated Ocean Drilling Program Expedition 320/321 scientific prospectus; Pacific equatorial age transect

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doi: 10.2204/iodp.sp.320321.2008
Author(s): Palike, Heiko; Lyle, Mitchell W.; Ahagon, Naokazu; Raffi, Isabella; Gamage, Kusali; Alvarez Zarikian, Carlos A.
Author Affiliation(s): Primary:
University of Southampton, National Oceanogarphy Centre, Southampton, United Kingdom
Other:
Texas A&M University, United States
Hokkaido University, Japan
Universita G. D'Annunzio, Italy
Source: Scientific Prospectus (Integrated Ocean Drilling Program), Vol.320/321, 101p. Publisher: IODP Management International, College Station, TX, United States. ISSN: 1932-9415
Note: In English. 73 refs.
Summary: As the world's largest ocean, the Pacific is intricately linked to major changes in the global climate system. Throughout the Cenozoic, Pacific plate motion has had a northward component. Thus, the Pacific is unique in that the thick sediment bulge of biogenic-rich deposits from the currently narrowly focused zone of equatorial up- welling is slowly moving away from the Equator. Hence, older sections are not deeply buried and can be recovered by drilling. Previous drilling in this area during Ocean Drilling Program (ODP) Legs 138 and 199 was remarkably successful in giving us new insights into the workings of the climate and carbon system, productivity changes across the zone of divergence, time-dependent calcium carbonate dissolution, bio- and magnetostratigraphy, the location of the Intertropical Convergence Zone (ITCZ), and evolutionary patterns for times of climatic change and upheaval. Together with older Deep Sea Drilling Project drilling in the eastern equatorial Pacific, both legs also helped to delineate the position of the paleoequator and variations in sediment thickness from ∼150°W to 110°W. The Pacific equatorial age transect (PEAT) science program is based on Integrated Ocean Drilling Program (IODP) Proposal 626 and consists of Expeditions 320 and 321, grouped into one science program. The goal is to recover a continuous Cenozoic record of the equatorial Pacific by drilling at the paleoposition of the Equator at successive crustal ages on the Pacific plate. Records collected from Expeditions 320 and 321 are to be joined with records of previous drilling during ODP Legs 138 and 199 to make a complete equatorial Pacific record from 0 to 55 Ma. Previously, ODP Legs 138 and 199 were designed as transects across the paleoequator in order to study the changing patterns of sediment deposition across equatorial regions at critical time intervals. As we have gained more information about the past movement of plates and when in Earth's history "critical" climate events took place, it becomes possible to drill an age transect ("flow-line") along the position of the Pacific paleoequator. The goal of this transect is to target important time slices where calcareous sediments have been best preserved and the sedimentary archive will allow us to reconstruct past climatic and tectonic conditions. Leg 199 enhanced our understanding of extreme changes of the calcium carbonate compensation depth (CCD) across major geological boundaries during the last 55 m.y. A very shallow CCD during most of the Paleogene makes it difficult to obtain well-preserved sediments during these stratigraphic intervals, but the strategy of site locations for the current two expeditions is designed to occupy the most promising sites and to obtain a unique sedimentary biogenic sediment archive for time periods just after the Paleocene/Eocene boundary event, Eocene cooling, the Eocene-Oligocene transition, the "one cold pole" Oligocene, the Oligocene-Miocene transition, and the Miocene. These new cores and data will significantly contribute to the objectives of the IODP Extreme Climates Initiative and will provide material that the previous legs were not able to recover. For logistical reasons, the PEAT science program is composed of two expeditions but is being implemented as a single science program to best achieve the overall objectives of Proposal 626. Participants on both expeditions (as well as approved shore-based scientists) will comprise a single science party with equal access to data and materials from both cruises. Sampling aboard the ship will be minimal, and the bulk of the sampling will be completed postcruise. The operational plan is to occupy eight sites along the age transect with the goal of recovering as complete a sedimentary succession as possible. This will probably require three holes to be cored at each site with wireline logging operations in one hole. Basement will be tagged in at least one of the holes. Expedition 320 will primarily sample the Paleogene sites (proposed Sites PEAT-5C, 4C, 3C, and 1C). Expedition 321 will core the Neogene sites (proposed Sites PEAT-2C, 6C, and 7C).
Year of Publication: 2008
Research Program: IODP Integrated Ocean Drilling Program
ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; 20 Geophysics, Applied; Basalts; Basement; Calcium carbonate; Carbon; Carbon cycle; Carbon dioxide; Carbonate sediments; Cenozoic; Downhole methods; Drilling; Equatorial Pacific; Expedition 320; Expedition 321; Geochemical cycle; Geophysical methods; Geophysical profiles; Geophysical surveys; Geotraverses; Igneous rocks; Integrated Ocean Drilling Program; Isotope ratios; Isotopes; Leg 199; Marine drilling; Marine sediments; Mid-ocean ridge basalts; O-18/O-16; ODP Site 1218; ODP Site 1219; Ocean Drilling Program; Ocean circulation; Oxygen; Pacific Ocean; Paleo-oceanography; Paleoclimatology; Paleoecology; Paleoenvironment; Paleomagnetism; Planning; Productivity; Programs; Reconstruction; Sea-surface temperature; Sediments; Seismic methods; Seismic profiles; Stable isotopes; Surveys; Tertiary; Upwelling; Volcanic rocks; Well logs
Coordinates: N051844 N120405 W1261700 W1420942
N023028 N035000 W1175811 W1231222
N085300 N085300 W1352200 W1352200
N074800 N074800 W1420100 W1420100
Record ID: 2008116954
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