A proposed new Precambrian skarn deposits in the Arabian shield

Abstract

The volcanosedimentary arc-related skarn deposits are the predominant types in the Arabian Shield (AS). However, the post-amalgamation extraordinary marine basins with carbonate successions exist in the AS, intruded by different types of granite plutons, and dissected by major shear zones. Therefore, all the recipes for skarn deposits are mature at the contact between the carbonate succession in the marine molasse basins and granite plutons. Magnetic data and ASTER data were integrated with the geochemical database to locate the preliminary areas for further exploration in the Murdama basin. The Murdama basin (72,000 km2), which is the locality for the Murdama limestone, has a higher magnetic anomaly at the contact with post-Murdama granite batholiths, but the magnetic anomaly becomes significant at the contact with the Idah granitic suite. The shallow-seated structural magnetic lineaments within the Murdama basin and at the eastern boundary of the basin are controlled by the Najd fault system (NFS). The calc-silicate mineral alteration zones were evolved at the contact between the Murdama group and the Idah suite, with no extent for the alteration zones along the fracture network or at the contact with the Abanat suite. Meanwhile, the Idah suites are the causative plutons for the Qitan and An Nimriyah South reduced skarns that were recorded from the Murdama basin. The preliminary results from this study based on the integration of different datasets suggest the existence of reduced skarn deposits at the contact between the Murdama basin and Idah causative plutons