Topics on carbonate relevant topics by IODP

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doi: 10.5575/geosoc.2017.0081
Author(s): Kawahata, Hodaka; Yokoyama, Yusuke; Kuroda, Junichiro; Iryu, Yasufumi; Kano, Akihiro
Author Affiliation(s): Primary:
University of Tokyo, Atmosphere and Ocean Research Institute, Tokyo, Japan
Tohoku University, Japan
Volume Title: Chishitsugaku Zasshi Journal of the Geological Society of Japan
Source: Chishitsugaku Zasshi = Journal of the Geological Society of Japan, 124(1), p.35-45. Publisher: Nippon Chishitsugaku Gakkai, Tokyo, Japan. ISSN: 0016-7630
Note: In Japanese with English summary. 34 refs.; illus., incl. charts, sketch map
Summary: Integrated Ocean Drilling Program (IODP) drilled into coral reefs, deep-water coral mounds and sediments to understand the change of climate, and biogeochemical cycle. IODP Expedition 310 around Tahiti enabled to delineate the course of last deglacial sea level rise and its impact on reef growth and geometry at this island. Amplitude of the sea-level jump around melt water pulse-1A (MWP-1A) was estimated at 12-22 m (most likely 14-18 m). Sea-surface temperature variations in 20-10 kyr indicated a temperature drop of 1.5°C at the Younger Dryas. IODP Expedition 325 recovered Pleistocene reef materials around Great Barrier Reef. More than 1,000 radiometric dates revealed detailed sea level pictures before and after the last glacial maximum (LGM: 20,000 years ago). We successfully reported more than 5°C lowering of SST during the LGM. IODP Expedition 307 revealed the interior of a deep-water coral mound at ∼800 m deep in Northern East Atlantic. Our age model based on Sr isotope recognized two growth stages; the depositionally continuous lower reef (2.6-1.7 Ma) accumulated under the low-amplitude relative sea-level change, and the discontinuous upper reef (1.0 Ma to mid-Holocene) developed under the high-amplitude relative sea-level change. The reef initiation was temporally correlated to the global cooling at the beginning of Pleistocene, when modern circulation was established in Atlantic. IODP Expedition 320/321 recovered a series of equatorial Pacific sediments covering the past 53 million years. Cenozoic evolution of carbonate compensation depth in the equatorial Pacific was reconstructed. It tracks a long-term deepening from 3.0-3.8 km during the Eocene to 4.6 km at present, which is superimposed by large fluctuations during the middle to late Eocene, and ended with a sharp >500 m deepening during the Eocene-Oligocene transition. Those variations are closely linked to changes in global climate and carbon cycle.
Year of Publication: 2018
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Anthozoa; Atlantic Ocean; Carbonate sediments; Cenozoic; Cnidaria; Coral Sea; Deep-sea environment; East Pacific; Eocene; Expedition 307; Expedition 310; Expedition 325; Expeditions 320/321; French Polynesia; Great Barrier Reef; Great Barrier Reef Environmental Changes; Integrated Ocean Drilling Program; Marine environment; North Atlantic; North Pacific; Northeast Atlantic; Northeast Pacific; Oceania; Oligocene; Pacific Equatorial Age Transect; Pacific Ocean; Paleo-oceanography; Paleoclimatology; Paleoecology; Paleogene; Pleistocene; Polynesia; Porcupine Seabight; Quaternary; Reef builders; Reefs; Sea-level changes; Sediments; Society Islands; South Pacific; Southeast Pacific; Southwest Pacific; Tahiti; Tahiti Sea Level Expedition; Tertiary; Upper Pleistocene; Upper Weichselian; Weichselian; West Pacific; Younger Dryas
Coordinates: S174600 S172900 W1492400 W1493600
S195100 S152800 E1502900 E1454900
N512200 N512700 W0113300 W0114400
Record ID: 2018101226
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