More than thirty years ago,microprobe analysis introduced the possibility of analyzing quantitatively in situ small surfaces of polished sections ,redering obsolete many of the optical measurements and other data that had been presented in many standard ore-mineralogy textbooks,and thus a new approach to the subject was called for.in addition ,it sh…
Basement rocks are exposed on the wastern and northern flanks of the ombilin II study are,they consist of metasediments,limestone and granodiorite .these rocks from the source rocks for the sediments found in the ombilin basin.they range in age from permo-carboniforous to triassic.
Coal-rich Tertiary sediments of the ombilin II coal field,west sumatra occur within a structurally complex foult bounded graben formed as a resoult of subduction of the pacific plate beneath sumatra.tectonic activity associated with foult movement appears to have influenced the caracter of the coal seams.grouth foulting my be responsible for areas o…