Lithologic control of frictional strength variations in subduction zone sediment inputs

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doi: 10.1130/GES01546.1
Author(s): Ikari, Matt J.; Kopf, Achim J.; Hüpers, Andre; Vogt, Christoph
Author Affiliation(s): Primary:
University of Bremen, MARUM-Center for Marine Environmental Sciences, Bremen, Germany
Volume Title: Geosphere (Boulder, CO)
Source: Geosphere (Boulder, CO), 14(2), p.604-625. Publisher: Geological Society of America, Boulder, CO, United States. ISSN: 1553-040X
Note: In English. 137 refs.; illus., incl. 3 tables, sketch map
Summary: At convergent margins, marine sediments deposited seaward of the subduction zone forearc on the incoming plate (the "subduction inputs") represent the initial condition for geomechanical processes during subduction. The frictional strength of these sediments is a key parameter governing deformation during subduction, which is controlled to first order by lithologic composition. We combine here the results of laboratory friction experiments and quantification of mineral assemblage for scientific drilling samples recovered from three particularly well-studied subduction zones: the Nankai Trough (southwestern Japan), the Japan Trench (northeastern Japan), and Costa Rica. In the Japan Trench, frictionally weak smectite-rich pelagic clay contrasts sharply with stronger, more siliceous hemipelagic material. This strength contrast dictates the stratigraphic position of initial plate boundary formation and influences slip behavior of the shallow megathrust. In the Costa Rica subduction zone, relatively weak clay-rich hemipelagic sediment overlies frictionally strong pelagic nannofossil oozes and chalks, which could be a factor for the development of features such as a small amount of offscraping near the toe and subduction erosion where ooze or chalk dominates. In the Nankai Trough, however, a wide range of frictional strength values is observed that does not correlate with clay mineral content. In this case, mechanical behavior at Nankai is likely influenced by other factors related to diagenesis or fluid overpressuring.
Year of Publication: 2018
Research Program: DSDP Deep Sea Drilling Project
IODP Integrated Ocean Drilling Program
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 18 Geophysics, Solid-Earth; Asia; Case studies; Central America; Clay minerals; Continental margin; Cores; Costa Rica; Costa Rica Seismogenesis Project; DSDP Site 297; DSDP Site 436; Deep Sea Drilling Project; East Pacific; Expedition 344; Expeditions 343/343T; Experimental studies; Far East; Friction; IODP Site C0011; IODP Site C0012; IODP Site C0019; IODP Site U1381; IODP Site U1414; IPOD; Integrated Ocean Drilling Program; Japan; Japan Trench; Japan Trench Fast Drilling Project; Laboratory studies; Leg 170; Leg 190; Leg 205; Leg 31; Leg 56; Marine sediments; Middle America Trench; Mineral composition; NanTroSEIZE; Nankai Trough; North Pacific; Northeast Pacific; Northwest Pacific; ODP Site 1039; ODP Site 1173; ODP Site 1177; ODP Site 1253; Ocean Drilling Program; Pacific Ocean; Philippine Sea; Plate convergence; Plate tectonics; Pore pressure; Sediments; Sheet silicates; Shikoku Basin; Silicates; Soil mechanics; Strength; Subduction; Subduction zones; West Pacific
Coordinates: N324944 N324945 E1365256 E1365254
N321500 N321500 E1350200 E1350200
Record ID: 2018037248
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