济阳坳陷早第三纪的两次海侵及其后的地质演化

TWICE TRANSGRESSIONS AND THE FOLLOWINC GEOLOGIC EVOLUTION OF THE JIYANG DEPRESSION DURING THE EOGENE PERIOD

摘要:

Abstract:

It was proved by the palaeontological, mineralogical, petrological and geochemical studies that the transgressions had twice taken place in the Eogene period in the Jiyang depression. The first one took place when the middle and upper parts of the Shahejie-4 Formation in the Eocene series was deposited; the second one occurred when the lower and middle parts of the Shahejie—1 Formation in the Oligocene was formed. The transgressions changed the continent into a lagoon in this area. After the transgressions ...