| Morawan Formation | |
| Type: | Formation |
| Age: | Chattian |
| Period: | Chattian |
| Region: | Hokkaido |
| Unitof: | Kawakami Group |
| Subunits: | unnamed, Kamirawan, Lower Hard Shale, Middle Hard Shales, Upper tuffaceous silstone |
| Underlies: | Kiroro Formation |
| Thickness: | 500m (1,600feet) |
The Morawan Formation is a Chattian age siliceous marine geological formation of the Oligo-Miocene Japanese Kawakami Group of eastern Hokkaido prefecture.[1] [2] [3] The formation is fossil rich and contains source units where toothed baleen whales (Aetiocetidae) and Desmostylians have been discovered.[4]
The Morawan Formation is a very siliceous unit containing hard platy shales interbedded with tuffaceous mudstones and sandstones, and some pumice. The unnamed lower member is a hard platy shale alternating with beds of tuffaceous mudstones and sandstones, the Kamirawan member is a tuffaceous sandstone with pumice, the Lower Hard Shale is a very siliceous hard shale with tuffaceous sandstones and mudstones, and the Middle Hard Shales and the Upper tuffaceous siltstone are similar.[5]
Fossil species from the Morawan Formation include: