Phra Wihan Formation

The Early Cretaceous Phra Wihan Formation is the second lowest member of the Mesozoic Khorat Group which outcrops in Northeast Thailand.
Comprises fine- to coarse-grained sheet and channelled sandstone beds and rarer variegated siltstone and mudstone. Intermittent conglomerate beds.
Deposited in a fluvial environment dominated by high-energy, shallow braided rivers with subordinate lower energy meandering river systems and associated flood plains.
The Phra Wihan Formation is considered to be Berriasian-Valanginian in age based on palynological analysis.
Sauropod tracks have been recorded from this formation.