The Oligocene Epoch. The Oligocene Epoch, right smack in the middle of the Tertiary Period (and end of the Paleogene), lasted from about 33.9 to 23 million years ago.*. Although it lasted a "short" 11 million years, a number of major changes occurred during this time.

Oligocene Epoch, third and last major worldwide division of the Paleogene Period (65.5 million to 23 million years ago), spanning the interval between 33.9 million to 23 million years ago. The Oligocene Epoch is subdivided into two ages and their corresponding rock stages: the Rupelian and the Chattian .

31/01/2022 · The Oligocene is an epoch of the Paleogene period and the Cenozoic era, extending from 33.9 to 23.0 million years ago. The Oligocene marked the start of the cooling trend that would continue for the rest of the Cenozoic, until today.

major early Oligocene unconformity. 3- Following a stable 87Sr/86S ratio during latest Cretaceous - Eocene (Elderfield, 1986), the increasing rate of 87Sr/86Sr during the Oligocene-Present interval (Fig. 3) suggests enrichment of ocean waters by sialic material, corresponding to a period of enhanced continental erosion. This

Second period (syn-rift): This period took place from Late Eocene to Early Miocene. A series of NE-SW faults were formed due to vigorous subduction and extension activities [1]. The Cuu Long basin was formed during this period and underwent two rifting phases: true rift phase from Middle Eocene to Oligocene and late rift phase in Early Miocene [6].