1 Eocene through lower Oligocene lacustrine shales and Oligocene through lower Miocene lacustrine and deltaic coaly shales are the mature source rocks.

2 The differences between Oligocene series in the east and west are demonstrated.

3 There are four hydrocarbon source rocks, Palaeocene, Eocene, Oligocene and Miocene.

4 It peaked in the Oligocene Epoch around 34 million years ago in Eurasia, and again in the Miocene Epoch about 10 million years ago in Eurasia and Africa.

5 Paleogene Oligocene Linhe formation ( E _ 3 J ) and Eocene Wulate formation ( E _ 2 wl ).

6 In late Eocene - Oligocene, that is red coarse sediment.

7 Oligocene erosion had truncated the sediments draped over the dome.

8 The uplifting, right-lateral strike-slip shearing, tilting and southward shearing of the Altai Mountains in Xinjiang have affected, since Oligocene, the drainage systems evolution and development.

9 Venezuela, oil is produced from lenticular sandstone beds of the Oligocene oficina Formation.

10 The eastern China Continent has entered into the stage of rifting continental margin since Oligocene.

11 Beibu Wan Basin was a lake in the middle Eocence - Lower Oligocene.

12 The prototype basin in Jurassic was a weakly extending depression; Begining Oligocene epoch, the basin was becoming intensively compressed and the structure distribution framework today was formed.

13 Based on the statistics of core analysis data, the Oligocene sediment is simplified as four formation components: terrigenous elastic minerals, carbonate, clay minerals, and porosity.

14 The middle Jurassic Yeba formation volcanics, Paleocene biotite granite porphyry, Miocene quartz monzonite and Oligocene granite porphyry could be found in the ore field.

15 The high relative abundance of the fossil planktonic algae indicates the high primary surface productivity of the palaeo-lake within the Oligocene.

16 The main hydrocarbon source rocks for the basins lacustrineplain sediments from Oligocene to Middle Miocene.

17 The boundaries between the Upper Cretaceous and Paleogene, Paleocene and Eocene, and Eocene and Oligocene in China nearly accord with corresponding ones elsewhere in the world.