Sulfide Dissolution and Awaruite Formation in Continental Serpentinization Environments and Its Implications to Supporting Life

Serpentinization environments are key locations that support microbial communities by the abiogenic formation of reduced species associated with peridotite alteration. Here we studied partially serpentinized peridotites from Chimaera seeps (Turkey), an active continental serpentinization system vents highly methane-rich fluids, to investigate impact water-rock interaction on sulfide and metal mineralogy its implications supporting communities. Using high-resolution scanning electron microscopy, microprobe analysis, transmission microscopy found diverse pentlandite decomposition features precipitation secondary sulfides including millerite, heazlewoodite, as well Cu-bearing sulfides, native Cu, awaruite (Ni3Fe). Awaruite forms dense veinlets single crystal platelets tens nanometers in size, which is formed desulphurization pentlandite. In addition, nanometer-sized intimately intergrown serpentine suggesting growth during alteration a dissolution-precipitation process, likely methane- H2-rich but sulfur-undersaturated fluids. Based sulfur isotope signatures infer mantle mid-ocean ridge origin minerals first stage partial formation. Subsequent ongoing fluid-rock causes significant resulting porosity release of, amongst others, H2S Fe. These may provide source nutrients for these comparatively nutrient-starved, low-temperature environments.