Geochemistry and Thermal analyses in subduction zone serpentine (SE Turkey)

Abstract

This Studying serpentinites requires a thorough understanding of their original rock types and their geological history before undergoing serpentinization. The chemical composition analysis and TGA analysis of serpentinites indicates that certain elements tend to remain relatively stable in terms of distribution even as the serpentinites undergo serpentinization. This stability in elements like rare earth elements (REE) can serve as a valuable tool in determining both the original rock type and potential magmatic processes that occurred prior to serpentinization. However, interpreting trace element data from serpentinites that have been subducted presents challenges. This is primarily due to the presence of elevated levels of light rare earth elements (REE), which seem to be independent of the original rock type. In such cases, we suggest that these enrichments are likely not directly linked to the serpentinization process itself, but rather stem from interactions between fluids derived from sedimentary sources and the rock within the subduction environment after serpentinization has taken place. The trace element abundances, when normalized to chondrites, exhibit a range between 30-90 ppm. In relation to chondrites, there is a distinct decrease in elements such as Sr, Rb, K, and Y while there is an increase in elements like Ba and U (by a factor of 93). Minerals display a negative anomaly for elements P, K, Sr, Ti, Zr and Y, and a pronounced positive anomaly for Ta, Nd and U.