| 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′N103°54′E / 16.1°N 103.9°E | 
| Approximate paleocoordinates | 14°18′N111°24′E / 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 | 
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. [1] [2] [3]
Sauropod (fossil) tracks have been recorded from this formation. [4]
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