Geochemistry of Carboniferous Sandstones （Sardar Formation）, East-Central Iran： Implication for Provenance and Tectonic Setting
摘要
Geochemical analysis of sandstones from the Sardar Formation (from two stratigraphic successions) in east-central Iran were used for identification of geochemical characterization of sandstones, provenance and tectonic setting. Sandstones in the two lithostratigraphic successions have similar chemical compositions suggesting a common provenance. Bulk-rock geochemistry analysis of Carboniferous sandstones from Sardar Formation indicates that they are mainly quartz dominated and are classified as quartzarenites, sublitharenites and subarkoses, derived from acid igneous to intermediate igneous rocks. Discrimination function analysis indicates that the sandstones of Sardar Formation were derived from quartzose sedimentary provenance in a recycled orogenic setting. Also, major and trace elements in sandstones of Sardar Formation (e.g., K 2 O/Na 2 O vs. SiO 2 ) indicate deposition in a stable passive continental margin (PM). Chemical index of alteration (CIA) for these rocks (>65%) suggests a moderate to relatively high degree of weathering in the source area.