Leg 198 synthesis; a remarkable 120-m.y. record of climate and oceanography from Shatsky Rise, Northwest Pacific Ocean

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doi: 10.2973/odp.proc.sr.198.101.2006
Author(s): Bralower, Timothy J.; Premoli Silva, Isabella; Malone, Mitchell J.
Ocean Drilling Program, Leg 198, Shipboard Scientific Party, College Station, TX
Author Affiliation(s): Primary:
University of North Carolina at Chapel Hill, Department of Geological Sciences, Chapel Hill, NC, United States
Other:
Universita di Milano, Italy
Ocean Drilling Program, United States
Pennsylvania State University, United States
Stanford University, United States
University College London, United Kingdom
Indiana University at Bloomington, United States
University of Florida, United States
University of Wales, United Kingdom
University of Michigan, United States
University of Queensland, Australia
Stockholm Universitet, Sweden
James Cook University of North Queensland, Australia
Tohoku University, Japan
University of Massachusetts at Amherst, United States
California State University, United States
Japan Marine Science and Technology Center, Japan
University of Oxford, United Kingdom
Universität Bremen, Federal Republic of Germany
Lamont-Doherty Earth Observatory, United States
University of California at Santa Cruz, United States
Volume Title: Proceedings of the Ocean Drilling Program; scientific results; extreme warmth in the Cretaceous and Paleogene; a depth transect on Shatsky Rise, Central Pacific; covering Leg 198 of the cruises of the drilling vessel JOIDES Resolution; Yokohama, Japan, to Honolulu, Hawaii; Sites 1207-1214; 27 August-23 October 2001
Volume Author(s): Bralower, Timothy J.; Premoli Silva, Isabella; Malone, Mitchell J.; Arthur, Michael A.; Averyt, Kristen B.; Bown, Paul R.; Brassell, Simon C.; Channell, James E. T.; Clarke, Leon J.; Dutton, Andrea; Eleson, Jason W.; Frank, Tracy D.; Gylesjo, Susanne; Hancock, Haidi J. L.; Kano, Harumasa; Leckie, R. Mark; Marsaglia, Kathleen M.; McGuire, Jennifer; Moe, K. T.; Petrizzo, Maria Rose; Robinson, Stuart A.; Röhl, Ursula; Sager, William W.; Takeda, Kotaro; Thomas, Deborah; Williams, Trevor; Zachos, James C.
Source: Proceedings of the Ocean Drilling Program; scientific results; extreme warmth in the Cretaceous and Paleogene; a depth transect on Shatsky Rise, Central Pacific; covering Leg 198 of the cruises of the drilling vessel JOIDES Resolution; Yokohama, Japan, to Honolulu, Hawaii; Sites 1207-1214; 27 August-23 October 2001, Timothy J. Bralower, Isabella Premoli Silva, Mitchell J. Malone, Michael A. Arthur, Kristen B. Averyt, Paul R. Bown, Simon C. Brassell, James E. T. Channell, Leon J. Clarke, Andrea Dutton, Jason W. Eleson, Tracy D. Frank, Susanne Gylesjo, Haidi J. L. Hancock, Harumasa Kano, R. Mark Leckie, Kathleen M. Marsaglia, Jennifer McGuire, K. T. Moe, Maria Rose Petrizzo, Stuart A. Robinson, Ursula Röhl, William W. Sager, Kotaro Takeda, Deborah Thomas, Trevor Williams and James C. Zachos; Ocean Drilling Program, Leg 198, Shipboard Scientific Party, College Station, TX. Proceedings of the Ocean Drilling Program, Scientific Results (CD ROM), Vol.198, 47p. Publisher: Texas A&M University, Ocean Drilling Program, College Station, TX, United States. ISSN: 1096-2514
Note: In English. Also available on CD-ROM in PDF format and on the Web in PDF or HTML. 100 refs.CD-ROM, ISSN 1096-2514; WWW, ISSN 1096-7451; illus., incl. strat. cols., sketch map
Summary: Samples collected from a depth transect of eight sites during Ocean Drilling Program Leg 198 to Shatsky Rise contain a remarkable sedimentary record of surface and deepwater circulation in the tropical Pacific over the past 120 m.y. In addition, basement sills recovered provide valuable constraints on the age and origin of the volcanic foundations of the rise. The sediments recovered contain evidence of the long-term transition from greenhouse to icehouse climate state and of several abrupt climate change events. Shatsky Rise cores contain an exceptional record of an Oceanic Anoxic Event in the early Aptian, with some of the highest organic carbon contents measured in pelagic sediments. These strata contain exceptionally preserved organic compounds including the oldest known alkenones. Organic geochemistry suggests that bacterial activity played a significant role in sequestering organic carbon. Stable isotope data from Upper Cretaceous and Paleogene sediments reveal several abrupt switches in the sources of intermediate waters bathing Shatsky Rise. Neodymium isotopes also show evidence for these changes and help to identify source regions in the North Pacific, Southern Ocean, and, possibly, Tethys. Strong evidence exists in Shatsky cores for the mid-Maastrichtian (∼69 Ma) global extinction of inoceramids, a long-ranging, widespread group of bottom-dwelling clams. Stable and neodymium isotopes combined with biotic data show changes in intermediate water sources at this time as well as significant changes in surface water oceanography. Shatsky Rise sites contain high-quality records of the Cretaceous/Tertiary boundary event. Detailed nannofossil assemblage studies demonstrate that the survivor taxa are those that were adapted to unstable environmental conditions of shelves, including taxa that have cyst stages. The Paleogene sedimentary record from Shatsky Rise is strongly cyclic with variations in the amount of dissolution. Superimposed on this record are "hyperthermal" episodes including the Paleocene/Eocene Thermal Maximum and events in the early late Paleocene and early Eocene. The PETM on Shatsky Rise contains evidence for 5°C warming of tropical sea-surface temperatures, major reorganization of benthic and planktonic communities, and pronounced short-term shoaling of the lysocline. Oxygen isotope and Mg/Ca data demonstrate warming of surface and intermediate waters during the early Eocene and help constrain the timing of the acceleration of Antarctic glaciation during the middle Eocene. Recovery of basaltic sills provides valuable age and geochemical constraints for interpreting the origin of Shatsky Rise. Radiometric ages confirm previous suggestions that this large igneous province was emplaced rapidly.
Year of Publication: 2006
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Algae; Aptian; Basalts; Biostratigraphy; Cenozoic; Climate change; Cores; Cretaceous; Foraminifera; Geochemistry; Igneous rocks; Invertebrata; K-T boundary; Leg 198; Lower Cretaceous; Lower Paleocene; Marine sediments; Mesozoic; Microfossils; Mid-ocean ridge basalts; Nannofossils; North Pacific; Northwest Pacific; Ocean Drilling Program; Ocean floors; Pacific Ocean; Paleo-oceanography; Paleocene; Paleoclimatology; Paleoenvironment; Paleogene; Plantae; Protista; Radiolaria; Reconstruction; Sediments; Shatsky Rise; Stratigraphic boundary; Tertiary; Upper Cretaceous; Volcanic rocks; West Pacific
Coordinates: N313400 N374800 E1624600 E1571500
Record ID: 2006077738
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