Fusulinacean biostratigraphy and carbonate petrography of Khao Khwang and Khao Khad formations, Saraburi province

Abstract

These research purposes are to study petrography, fusulinids assemblage and age and study biostratigraphy correlation of Khao Khwang and Khao Khad Formations, Saraburi province.

The fusulinids from the study area belong to 5 families, 11 subfamilies, 15 genera and 15 species including Robustoschwagerina, Yangchienia, Parafusulina loeyensis, Parafusulina gigantea, Laosella edoensis, Pseudofusulina, Chusenella chihsiaensis, Chusenella (Chusenella) shengi, Verbeekina verbeeki, Misellina, Pseudodoliolina, Thailandina buravasi, Neoschwagerina megasphaerica, Colania douvillei, Lepidolina shiraiwensis, Presumatrina ciryi, Sumatrina annae and Sumatrina cf. longissima. These fusulinids indicated that Khao Khad Formation was deposited oldest in Sakmarian to Yakhtashian and youngest in Midian age and Khao Khwang Formation was deposited oldest in Murgabian and youngest in Midian age. The petrographic study indicates that the carbonate rocks of the study area could be classified to calcimudstone, bioclastic wackestones, bioclastic floatstone, bioclastic packstone, bioclastic rudstone and microbial boundstone. The depositional environments of these carbonate rocks were varied from tidal, shelf and slope deposit.

The Khao Khwang and Khao Khad Formations correlation indicated that these formations were deposited in different localities in the same age at least in Early Middle Permian to Late Middle Permian (Murgabian to Midian).