Geological characteristics of Sulit Air Copper deposit in Suma-tra Indonesia

Sulit Air copper deposit belongs to the Jurassic- early Cretaceous magma arc related copper-gold metallogenic period of Sumatra, Indonesia. In order to summarize the characteristics of this deposit and to guide the prospecting in this area, this article study the geology, petrology and geochemistry of Sulit Air. Geochemistry characteristic shows that the skarn rocks have more CaO and less Al2O3, K2O, Na2O content than the igneous rock;In the FAM diagram and FeOt-MgO-Al2O3 diagram, the skarn rock dropped near the igneous rocks area. Howev-er, the REE pattern of those two rocks are different, the Σw (REE) of igneous rock is higher than skarn rock; the skarn rocks have negative europium anomalies rather than positive anomalies in the igneous rock. In conclusion, the age of Sulit Air deposit is later than early-Jurassic and its ore-forming setting belongs to the post-orogenic and post-collisional volcanism.