Phra Wihan Formation
Geologic formation in Thailand
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The Early Cretaceous Phra Wihan Formation is the second lowest member of the Mesozoic Khorat Group which outcrops in Northeast Thailand.
| 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 | 16.1°N 103.9°E |
| Approximate paleocoordinates | 14.3°N 111.4°E |
| Region | Northeast Thailand (Khorat Basin) |
| Country | Thailand |
| Extent | Khorat Plateau |
| Type section | |
| Named for | Phra Wihan, an 11th-century Khmer Temple |
| Named by | Ward & Bunnag |
| Year defined | 1964 |
  Phra Wihan Formation (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.[1][2][3]
Sauropod (fossil) tracks have been recorded from this formation.[4]