Yerrapalli Formation
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| Yerrapalli Formation | |
|---|---|
| Stratigraphic range: Anisian ~ | |
| Type | Geological formation |
| Underlies | Bhimaram Formation |
| Overlies | Kamthi Formation |
| Thickness | 600 m (2,000 ft) |
| Lithology | |
| Primary | Mudstone, sandstone, caliche |
| Location | |
| Coordinates | 18°54′N 79°42′E / 18.9°N 79.7°E |
| Approximate paleocoordinates | 51°24′S 48°30′E / 51.4°S 48.5°E |
| Region | Andhra Pradesh, Telangana |
| Country | India |
| Extent | Pranhita–Godavari Basin |
| Type section | |
| Named for | Yerrapalli village |
| Named by | Jain et al. |
| Year defined | 1964 |
  Yerrapalli Formation (India)  Yerrapalli Formation (Telangana) | |
The Yerrapalli Formation is a Triassic geological formation consisting primarily of mudstones that outcrops in the Pranhita–Godavari Basin in southeastern India.[1] The Yerrapalli Formation preserves fossils of freshwater and terrestrial vertebrates as well as trace fossils of invertebrates.[2] The tetrapod fauna includes temnospondyl amphibians, archosauromorph reptiles, and dicynodonts.[3]
Most of the Yerrapalli Formation consists of red mudstones. The mudstones were deposited across a floodplain during the Anisian stage of the Middle Triassic. Smaller lenses of calcareous sandstone represent ephemeral streams that branched off from the larger channels that were the source of the floodplain sediments.[3] The climate of the region during the time is thought to have been monsoonal with both wet and dry seasons.[4]
The Yerrapalli Formation overlies the Kamthi Formation, underlies the Bhimaram Formation, and is conformable with both formations. Two members of the Yerrapalli Formation have been recognized; a lower member consisting of layers of red and purple clay with lenses of pale green clay and an upper member consisting of alternating layers of clay and fine-grained sandstone.[4]
