Fluid-driven Hydrovolcanic Activity along Fracture Zones and near Seamounts:Evidence from Deep-sea Fe-rich Spherules,Central Indian Ocean Basin  

作　　者：Ankeeta AMONKAR Sridhar D.IYER Elapavalooru V.S.S.K.BABU Natarajan SHAILAJHA Areef SARDAR S.MANJU 

机构地区：[1]CSIR-National Institute of Oceanography,Dona Paula,Goa 403004,India [2]Marine Science,School of Earth,Ocean and Atmospheric Sciences,Goa University,Goa 403206,India [3]Formerly with CSIR-National Institute of Oceanography,Dona Paula,Goa 403004,India [4]CSIR-National Geophysical Research Institute,Hyderabad,Telangana 500007,India [5]Department of Earth Science,Pondicherry University,Pondicherry 605014,India

出　　处：《Acta Geologica Sinica(English Edition)》2021年第5期1591-1603,共13页地质学报（英文版）

基　　金：The sediment samples were collected during several cruises(AAS-22,AAS-38 and SSD-48)under the auspices of the project“Surveys for Polymetallic Nodules”(GAP 2175)funded by the Ministry of Earth Sciences,New Delhi,India。

摘　　要：An insight on occurrence of Fe-rich spherules from the Central Indian Ocean Basin(CIOB)provides an understanding of their distribution at a water depth of>5,000 m.In the present study,Fe-rich spherules are identified to occur in two different sediment types(i.e.,siliceous and pelagic)and tectonic settings(i.e.near seamounts and fracture zones).These are single spheres or aggregates,of different sizes(63 to 390μm)and show textural variability(smooth/quenched,brickwork,corkscrew,interlocking and dendritic).A comparative study based on physical morphology and chemical composition suggests a common mechanism of formation.The association of spherules with fracture zones(FZ)and seamounts signifies that morpho-tectonic features play an important role in fluid-driven hydrovolcanism.Based on the evidence and geologic conditions existing in the basin,we conclude that molten fuel-coolant interaction(MFCI)coupled with submarine hydrothermal exhalations could be an ideal mechanism for the formation of spherules and Fe-particles.The accretion of the spherules on the surface sediments could be a result of recent volcanic phenomena,while those occurring at different depths(280-355,and 460-475 cm-bsf)within the sediment core indicate two different episodes.The study provides a global implication in understanding fluid-driven magmatism in a deep-sea intraplate environment.

关 键 词：Fe-rich spherules deep-sea sediments hydrovolcanic activity CIOB 

分 类 号：P736[天文地球—海洋地质]