Comparison of serpentinization in different tectonic environments:A case study of the Tianshan and North Qilian orogenic belts
Serpentine,a hydrated mineral with a water content of about 13％,holds great significance on Earth.It is widely distributed across various tectonic environments,such as the ocean floor,subduction zones,and fore-arcs.In addition to fluids,serpentine can also be enriched with fluid-mobile elements(B,Li,As,Sb,Pb,Cs,U,Sr and Ba)through the process of serpentinization.This makes serpentine a crucial host for fluids and these elements in different geological processes.However,different tectonic environments have varying temperatures and pressures,which can result in different properties of fluids.Serpentinization in different environments not only leads to the formation of different types of serpentines(e.g.,lizardite,antigorite),but also results in varying enriched characteristics of serpentine.Thus,further studies are required to understand these differences.By comparing literature data on serpentinite produced in different tectonic environments worldwide,as well as analyzing serpentinite samples from the Southwest Tianshan and Qilian Mountains orogenic belts,we have observed distinct enriched characteristics of B,Ba,and Cs in abyssal serpentinite and serpentinite found in subduction zones:①abyssal serpentinite has significantly higher B contents,suggesting a preference for B in serpentinite formation at lower temperatures;② serpentinite formed in subduction zones displays relatively higher Ba,Cs,and Pb contents,indicating a potential contribution from subducting sediments.This conclusion is valuable in interpreting the tectonic environment associated with serpentinite based on its compositional characteristics.
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