Sanya Fm

Hainan-offshore SW. The named section is located in No.6 Ying drill offshore, 69 km southwest of Sanya, Hainan. Named in 1981 by Hu Pingzhong and Su Houxi, the Nanhai Petroleum Branch of China National Petroleum Corporation.

The Sanya Formation is located between the Lingshui Fm and the Meishan Fm. It is a set of littoral-neritic clastic rocks, dominated by grayish-white sandy conglomerate, with a thin layer of variegated mudstone on the top. The 1768 to 1856 m section of No.6 Ying drill is the type section. No.6 Ying drill is dominated by terrestrial facies. The lithology is gray-white sandy conglomerate with thin layers of brown-red, yellow-green, brown-yellow, and other variegated mudstones. To the east, No.9 Ying drill transitions into marine gray-white sandstone, conglomerate sandstone, interbedded siltstone and gray mudstone. There is about 20-40m gray mudstone on the top. The total thickness is 88 to 429 m.

This group contains a small number of planktonic foraminifers Globigerina ciperoensis, Cassigerinella chipollensis, and more benthic species Asterigerina tentoria, Ammonia indica, Nephrolepidina sumatrensis, Autrotrilina howchini, Miogypsina polymorpha, etc., belonging to the upper part of the N4 zone to the N8 zone; calcareous nannofossils See Discoaster druggii, Sphenolithus belemnos, Helicosphaera ampliapertuta and other NN2-NN4 band molecules. Pollen is the combination of Alnipollenites-Dicolpopollis-Extrapunctatosporis.

Littoral facies. The west is dominated by terrestrial facies with coarser deposits, and the transition to the east is marine facies with finer deposits.