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Fluid discharge linked to bending of the incoming plate at the Mariana subduction zone

M. Du1,

1Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan 572000, China

X. Peng1,

1Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan 572000, China

W.E. Seyfried Jr.2,

2Department of Earth Science, University of Minnesota, 310 Pillsbury Drive E, Minneapolis, Minnesota 55455, USA

K. Ta1,

1Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan 572000, China

Z. Guo1,

1Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan 572000, China

S. Chen1,

1Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan 572000, China

I.-M. Chou1,3,

1Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan 572000, China
3954 National Center, U.S. Geological Survey, Reston, Virginia 20192, USA

J. Li1,

1Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan 572000, China

H. Xu1

1Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan 572000, China

Affiliations  |  Corresponding Author  |  Cite as  |  Funding information

Du, M., Peng, X., Seyfried Jr., W.E., Ta, K., Guo, Z., Chen, S., Chou, I.-M., Li, J., Xu, H. (2019) Fluid discharge linked to bending of the incoming plate at the Mariana subduction zone. Geochem. Persp. Let. 11, 1–5.

The Strategic Priority Research Program of the Chinese Academy of Sciences (XDB06020000) and the National key research and development plan of China (2016YFC0304900).

Geochemical Perspectives Letters v11  |  doi: 10.7185/geochemlet.1916
Received 31 January 2019  |  Accepted 9 May 2019  |  Published 5 June 2019
Copyright © The Authors

Published by the European Association of Geochemistry
under Creative Commons License CC BY-NC-ND 4.0




Figure 1 (a) Location of the newly discovered fluid discharge field at site M and two pockmarks at sites N and P (red dots) on the incoming plate of Mariana trench. (b) Enlarged shaded-relief map of red box in (a). The sites M, N and P (green circles) are situated on the base of the slopes of bending-related faults that have been extensively developed and pervasively cross the entire trench slope of the incoming plate in response to plate flexure. White triangles show the axis of the southern Mariana trench. The known serpentinite mud volcanoes (black dots in (a)) are exclusively located on the overriding plate of Mariana trench. White bars in (b) show blank areas where no multi-beam bathymetric data are available.
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Figure 2 Fluid discharge points and pockmarks in the southern Mariana trench. (a) A small fluid discharge point (#JL114-1 at 5445 m) in the eastern portion of site M. The yellow-reddish solidified materials marked by arrows at the margin of the crater consist mostly of iddingsite. (b) Close-up of the top of a fluid discharge point (#JL114-1 at 5445 m) showing a feeder channel with a diameter of ~ 0.6 m. (c) A pockmark (#JL115-1 at 5445 m) of ~5 m in diameter in the western portion of site M. The muds are primarily composed of iddingsite. (d) A shallow pockmark (#JL114-2 at 5445 m) that consists primarily of iddingiste in the western portion of site M. White materials marked by arrows are zeolites that are also low grade alteration products of basaltic rocks. (e) A fluid discharge point (#JL114-3 at 5445 m) with a blocked feeder channel in the eastern portion of site M. (f) An iddingsite pockmark (#JL144-1 at 6300 m) with a diameter of ~4 m and a depth of ~3 m at site N. (g) A small iddingsite pockmark (#JL146-1 at 6669 m) at site P. (h) A white Galatheid crab on a dark manganese crust that forms within iddingsite-rich muds at site M. (i) Blanket-like iddingsite muds with a dark manganese coating on the base of a fluid discharge point at site M.
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Figure 3 Highly altered and partly altered basement rocks associated with fluid discharge points. (a) A dark-green, fragile and highly altered basement rock (#JL115-Rock-11) recovered from site M. (b) Image in plane polarised light showing that the rock in (a) exhibits a mesh-like structure composed of reddish iddingsite (Idd) and black birnessite (Bi). The latter probably precipitated from seawater along fractures of the altered rocks in the late stage. (c) A partly altered basement rock recovered from the vicinity of site M (#JL116-Rock-6). Dotted cycles point out reddish iddingsite in the basaltic host. (d) Image in plane polarised light showing that the rock in (c) is primarily composed of augite (Aug), labradorite (La) and a cluster of reddish iddingsite (Idd).
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