Geochemistry and genesis of igneous rocks and skarn of Shahrak iron ore (Northeast of Kurdistan)

摘要

Shahrak iron deposit is located at the north of Sheikh-Besharat village, northwest of the city Hassan-Abad Yasukand, Kurdistan province. The study area includes igneous rocks, skarn zone, metamorphic zone (marble), and iron ore. Igneous rocks exposed in the district include calc-alkaline volcanic rocks with the dominant composition of rhyolite, andesite, dacite, trachyandesite, volcanoclastic (tuff) and intrusive rocks of diorite and granodiorite type, and carbonate rocks of Qom Formation (Miocene). Based on field studies, petrography of volcanic rocks and the skarn zone and Fe ore mineralography in the area, it can be said that iron mineralization and skarn formation occur adjacent to the igneous masses. The skarn index minerals are evidence of this event. The spider diagram patterns of rare earth elements of the Shahrak deposit samples normalized to the chondrite indicate more enrichment in light rare earth elements (LREE) than heavy rare earth elements (HREE). Positive Eu and negative Ce anomalies are characteristic of hydrothermal iron ore deposits. The different pattern of trace elements in the igneous rocks and the ore indicates their various geneses. The less important role of low salinity non-magmatic fluids in ore formation is concluded by chemical analysis results.