Investigation of the Relationships Between Iron Oxide - (Cu-Au) and Epithermal Precious Metal Mineralizing Systems in the Ar Rayn Terrane, Saudi Arabia

Colorado School Of Mines, Golden CO

Investigators

Abstract

Hitzman EAR-0207217 Iron oxide-(Cu-Au) deposits are currently a prime exploration target worldwide. Understanding of this class of deposits has been hindered by the scarcity of examples and by the large scale of the systems themselves. There are fundamental disagreements on several key features of this deposit class, particularly in regard to the source of the fluids responsible for alteration and mineralization and the role of specific magmas. Tied to these debates is how the iron oxide-Cu-Au class of deposits relates in time and space to other deposit types. Such linkages between deposit types are critical not only for mineral exploration but also for better understanding the geochemical and hydrodynamic aspects of large-scale mineralizing systems. The Late Proterozoic Ar Rayn terrane in central Saudi Arabia provides an ideal site to test the linkages between iron oxide systems and low-sulfidation epithermal gold deposits. The terrane contains a number of well exposed mineral deposits and prospects, including iron oxide-(Cu-Au) and epithermal precious metal deposits which appear to be genetically and temporally related based on geological relationships and limited geochronology. The deposits, though described in reports by the Saudi Arabian Deputy Ministry for Mineral Resources, are virtually unknown in the literature outside of Saudi Arabia. This project will document the geology and geochemistry of the deposits. Descriptive information from detailed outcrop mapping will be supplemented by mineralogic, fluid inclusion, and stable isotope geochemical studies designed to quantify physical and chemical conditions of the hydrothermal fluids across all parts of the zone of transition from apparently deep-seated, magnetite-rich, Fe-oxide-(Cu-Au) deposits to much shallower, low-sulfidation epithermal deposits. In addition, geochronological studies will allow determination of the temporal relationships of these mineralizing systems. These data will allow critical analysis of the possible linkage between iron oxide systems and low-sulfidation epithermal systems. The project will also aid in forging relationships between the Saudi Geological Survey and research groups in the United States.