Biostratigraphy of Tak Fa Formation at Khao Wong and Khao Chakkachan, Amphoe Hong Muang, Changwat Lop Buri with reference to Fusulinids

The purposes of this study are to identify the species of fusulinids and to study biostratigraphy and determine age of rock by using the fusulinids in the area of Khao Wong and Khao Chakkachan, Amphoe Nong Muang, Changwat Lop Buri. The fusulinids found in the investigated area belong to 13 species of 9 genera 4 families : Neofusulina lantenoisi Deprat, Neofusulinella cf. saraburiensis Toriyama, Kanmera, and Ingavat, Chusenella cf. schwagerinaeformis Sheng, Parafusulina gigantea (Deprat), Parafusulina loeyensis Pitakpaivan, Parafusulina. A. Dunbar and Skinner, Pseudofusulina sp. Dunbar and Skinner, Verbeekina verbeeki (Geinitz), Metadoliolina nongmuangensis sp. nov., Pseudodoliolina pseudolepida (Deprat), Colania douvillei (Ozawa), Sumarina annae (Volz), and Sumatrina cf. Longissima Deprat. Five biozones were recognized biostratigraphic zones : Pseudodoliolina pseudolepida – Neofusulinella lantenoisi zone, Parafusulina gigantea – Parafusulina loeyensis zone, Colania douvillei zone, Metadoliolina nongmuangensis zone, and Fusulinid barren zone. The age of Tak Fa formation at the Khao Wong and Khao Chakkachan areas is Middle Wordian to Middle Capitanian.