Exploring links between global climate and explosive arc volcanism in tephra-rich Quaternary sediments; a pilot study from IODP expedition 350 site 1437B, Izu Bonin rear-arc region

Author(s): Corry-Saavedra, Kate; Straub, Suzanne M.; Bolge, Louise; Schindlbeck, Julie Christin; Kutterolf, Steffen; Woodhead, Jon D.
Author Affiliation(s): Primary:
Barnard College, New York, NY, United States
Lamont-Doherty Earth Observatory, United States
Helmholtz Centre for Ocean Research Kiel, Germany
University of Melbourne, Australia
Volume Title: AGU 2015 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2015; American Geophysical Union 2015 fall meeting, San Francisco, CA, Dec. 14-18, 2015. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: Fallout tephra in marine sediment provide an excellent archive of explosive arc volcanism that can be directly related to the other parameters of climate change, such as ice volume data, IRD (ice-rafted debris) input, etc. Current studies are based on 'discrete' tephra beds, which are produced by major eruptions and visible with the naked eye. Yet the more common, but less explosive arc eruptions that are more continuous through time produce 'disperse' tephra, which is concealed by the non-volcanic host sediment and invisible to the eye. The proportion of disperse tephra in marine sediments is known to be significant and may be critical in elucidating potential synchronicity between arc volcanism and glacial cycles. We conducted a pilot study in young sediments of IODP Hole 1437B drilled at 31°47.3911'N and 139°01.5788'E at the rear-arc of the Izu Bonin volcanic arc. By means of δ18O (Vautravers, in revision), eleven climatic cycles are recorded in uppermost 120 meter of carbonate mud that is interspersed by cm-thick tephra fallout layers. We selected six tephra layers, ranging from 0.2 to 1.16 million years in age, and sampled those vertically, starting from carbonate mud below the basal contact throughout the typical gradational top into the carbonate mud above. From each tephra bed, volcanic particles (>125 micrometer) were handpicked. All other samples were powdered and leached in buffered acetic acid and hydroxylamine hydrochloride to remove the carbonate and authigenous fraction, respectively. Major and trace element abundances (except for SiO2) from all samples were determined by ICP-MS and ICP-OES methods. Strong binary mixing trends are revealed between the pure tephra end member, and detrital sediment component. The tephra is derived from the Izu Bonin volcanic front and rear-arc, while the sediment component is presumably transported by ocean surface currents from the East China Sea. Our data show that mixing proportions change systematically with sample percentage left after leaching and the stratigraphic position of sample, implying that the composition of the aluminosilicate fraction is an indicator of the percentage of disperse ash present in the carbonate mud. This data leave potential to investigate temporal trends. Our results are currently being refined with radiogenic isotope data.
Year of Publication: 2015
Research Program: IODP Integrated Ocean Drilling Program
IODP2 International Ocean Discovery Program
Key Words: 07 Marine Geology and Oceanography; Cenozoic; Climate change; Expedition 350; IODP Site U1437; International Ocean Discovery Program; Izu-Bonin Arc; Marine sediments; North Pacific; Northwest Pacific; Pacific Ocean; Quaternary; Sediments; Volcanism; West Pacific
Coordinates: N314723 N314724 E1390136 E1390134
Record ID: 2016106296
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