Seafloor manifestations of fluid seepage at the top of a 2000-metre-deep ridge in the eastern Nankai accretionary wedge; long-lived venting and tectonic implications

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doi: 10.1016/0012-821X(92)90096-E
Author(s): Lallemand, Serge E.; Glaçon, Georgette; Lauriat-Rage, Agnès; Fiala-Médioni, Aline; Cadet, Jean-Paul; Beck, Christian M.; Sibuet, Myriam; Iiyama, Jean Toshimichi; Sakai, H.; Taira, Asahiko
Author Affiliation(s): Primary:
Univ. Pierre et Marie Curie, Lab. Géol. Struct., Paris, France
Other:
Ec. Norm. Supér., France
Univ. Provence, France
Mus. Natl. Hist. Nat., France
Univ. Savoie, France
IFREMER, France
Chiba Univ., Japan
Volume Title: Fluids in convergent margins
Volume Author(s): Kastner, M., editor; Le Pichon, Xavier
Source: Earth and Planetary Science Letters, 109(3-4), p.333-346; Fluids in subduction zones, Paris, France, Nov. 5-6, 1991, edited by M. Kastner and Xavier Le Pichon. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X CODEN: EPSLA2
Note: In English. 26 refs.; illus. incl. 1 table, sketch maps
Summary: The results of the 1989 Kaiko-Nankai diving cruise to this wedge show that a narrow corridor on the top of a 2000 m deep ridge is characterized by concentrated surface manifestations of fluid seepage and chaotic outcrop orientations, suggesting active faulting along a right-lateral shear zone. Modern biological indicators of fluid venting include bivalve vesicomyid species and vestimentiferan tube worms. Ancient manifestations of fluid venting consist of similar vesicomyid species found in 20 and 150 k.y. concentrations. This suggests relatively constant biotypes. Carbonate deposits including fossil cemented shells were observed near active sites, either as 'paving stones' (diffuse seepage and cementation) cut by channels or as pinnacles (local seepage and cementation). Despite its proximity (< 15 km), a nearby 300 m deep site, where substantial fluid discharge occurs, seems to be completely separate from the 200 m deep ridge site. The 3800 m deep site differs from its shallower counterpart in terms of its sea-floor manifestations and the composition of its fluids. The sediment at the top of the ridge ranges in age approx 500 +- 300 k.y., which attests that the transition from a depositional to an erosional stage was younger than 800 but older than 200 k.y. This transition can be due to either the incorporation of this unit from the trench fill into the accretionary wedge front or the uplift of a slope basin. The first hypothesis leads to a 2.5 cm/yr minimum progradation rate associated with a 2.5 mm/yr minimum uplift rate from the palaeotrench to the present ridge. The second hypothesis implies a recent uplift of a 'piggy-back' basin at the minimum rate of 1 mm/yr. [Authors' abstract]
Year of Publication: 1992
Research Program: ODP Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; 24 Surficial Geology, Quaternary Geology; Accretionary wedges; Active faults; Biostratigraphy; Bivalvia; Cementation; Cenozoic; Deep-sea environment; Dehydration; Diagenesis; Ecology; Faults; Faunal list; Fluid phase; Holocene; Invertebrata; Leg 131; Marine environment; Marine sediments; Mid-ocean ridges; Mollusca; Nankai Trough; North Pacific; Northwest Pacific; Ocean Drilling Program; Ocean floors; Oceanography; Pacific Ocean; Pore water; Quaternary; Sedimentary rocks; Sediments; Seepage; Troughs; Vents; Vermes; West Pacific
Coordinates: N334800 N335000 E1375600 E1375330
Record ID: 1992024687
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom