Abstract
The chemical changes in oceanic crustal rocks during hydrothermal alteration were investigated through the Oman and Troodos ophiolite in order to evaluate seawater-rock interaction through the oceanic crust including Layer 3. Based upon the depth-profile and the correlation among 20 elements analyzed in this study, elements were classified into 6 groups: Group 1 (Ca, P, Al), Group 2 (Mg, Ni, Co, Cr), Group 3 (Fe, Ti, Na, Mn, Zn, Y), Group 4 (K, Rb, Ba), Group 5 (Li, Cd) and Group 6 (other elements such as Sr, Cu). Each profile reflects original rock composition and its modification during high and low temperature alteration. The degree of alteration was assessed by 87Sr/86Sr ratios of rocks and the abundance of secondary minerals. Heavy metals were leached from the lower oceanic crust.
