Phra Wihan Formation
| Phra Wihan Formation | |
|---|---|
| Stratigraphic range: Berriasian-Valanginian ~ | |
| Type | Geological formation |
| Unit of | Khorat Group |
| Underlies | Sao Khua Formation |
| Overlies | Phu Kradung Formation |
| Thickness | 150 m (490 ft) |
| Lithology | |
| Primary | Sandstone |
| Other | Siltstone, mudstone, conglomerate |
| Location | |
| Coordinates | 16°06′N 103°54′E / 16.1°N 103.9°E |
| Approximate paleocoordinates | 14°18′N 111°24′E / 14.3°N 111.4°E |
| Region | Northeast Thailand (Khorat Basin) |
| Country | Thailand |
| Extent | Khorat Plateau |
| Type section | |
| Named for | Khao Phra Wihan, an 11th-century Khmer Temple (Khao Phra Wihan National Park) |
| Named by | Ward & Bunnag |
| Year defined | 1964 |
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 (fossil) tracks have been recorded from this formation.