Meteoric Be-10 reveals a young, active accretionary prism and structurally complex decollement in the vicinity of the 2011 Tohoku Earthquake rupture
File(s)
Accepted version
Author(s)
Regalla, Christine
Bierman, Paul
Rood, Dylan H
Type
Journal Article
Abstract
We present new meteoric 10Be concentration data from marine sediment cores recovered during Integrated Ocean Drilling Program Expedition 343 (JFAST) that help constrain the age, origin, and internal structure of the frontal prism at the Japan trench in the vicinity of the 2011 Tohoku‐oki M9 earthquake rupture. 10Be sediment ages from the lower portion of the frontal prism range from ~0–10 Ma, with >60% of analyzed samples above the décollement yielding young ages <2 Ma. Repetition and inversion of high‐over‐low 10Be‐concentration sediments indicate the presence of stratigraphic inversions that correspond to faulting and imbrication of late Miocene and Quaternary sediments. The density of faults inferred indicates that the frontal prism has a fault spacing on the order of 10 s of meters, and the identification of faults in the underthrust section suggests that the plate boundary décollement may be a zone with multiple slip surfaces. Comparison of 10Be concentrations in the frontal prism with those of the incoming and forearc slope sediments indicates that the majority of the prism is sourced from accretion of Pacific Plate sediments, rather than from reworked frontal prism or slope sediments. These data suggest that over at least the past ~1–2 Ma, the décollement preferentially has localized at or near the base of the incoming sediment section, with relatively efficient sediment accretion occurring even in the presence of subducted horst‐and‐graben topography.
Date Issued
2019-11-10
Date Acceptance
2019-10-18
Citation
G3: Geochemistry, Geophysics, Geosystems: an electronic journal of the earth sciences, 2019, 20 (11), pp.4956-4971
ISSN
1525-2027
Publisher
American Geophysical Union
Start Page
4956
End Page
4971
Journal / Book Title
G3: Geochemistry, Geophysics, Geosystems: an electronic journal of the earth sciences
Volume
20
Issue
11
Copyright Statement
©2019. American Geophysical Union. All Rights Reserved. This is the accepted version of the following article: Regalla, C., Bierman, P., & Rood, D. H. ( 2019). Meteoric 10Be reveals a young, active accretionary prism and structurally complex décollement in the vicinity of the 2011 Tohoku earthquake rupture. Geochemistry, Geophysics, Geosystems, 20, 4956– 4971, which has been published in final form at https://doi.org/10.1029/2019GC008483
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000495511700001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Physical Sciences
Geochemistry & Geophysics
PLATE BOUNDARY FAULT
JAPAN TRENCH
TECTONIC EROSION
SUBDUCTION
ZONE
BERYLLIUM
OCEAN
SLIP
PA-231
Publication Status
Published
Date Publish Online
2019-10-26