Petrography and Geochemistry of the Tosham Hill Felsic Volcanics, Haryana

Abstract

Explosion breccia, tuff and felsite constitute the felsic volcanic rocks at Tosham Hill. Petrographically, the groundmass of tuff is distinct from that of felsite in being associated intimately with particles of iron ores. Geochemically, these rocks arc classified as potassic rhyolites and dacites. The trace elemental data show that explosion breccia is higher in Ba (230, 250ppm) than tuff and felsite (1O-60ppm); B(220ppm) and Sn (180 ppm) values predict significant economic concentrations of the latter at depth: quartz-porphyry dyke may perhaps be correlated with the Malani episode.