Mawson Formation
The Mawson Formation is a geological formation in Antarctica, dating to roughly between 185-181 million years ago and covering the Pliensbachian-Toarcian stages of the Jurassic Period in the Mesozoic Era. Vertebrate remains are known from the formation.
Description
The formation was deposited in an ancient lake, with hydrothermal influences, thanks to the relationships with the Kirckpatrick Basalt. Sedimentary interbeds deposited over lava flows of the Kirkpatrick Basalt during the Early Jurassic splitting of Gondwana represent unusual freshwater paleoenvironments, with hotter conditions that allow to the diversification of the microbes.According to Barrett, "...the basalt-dominated Mawson Formation and tholeiitic flows...are included in the Ferrar Group." The Mawson Formation consists of diamictites, explosion breccias, and lahar flows, evidence of magma entering water-saturated sediments. The Kirkpatrick Basalts have interbedded lake sediments with plant and fish fossils.
Fossil content
There abundant Fossils of microorganisms, as members of the group Archea and other who take advantage of the hydrothermal activitySpinicaudata
Fish
Insects
Fossil insect wings not described to the genus level are known from the formation.| Genus | Species | Location | Stratigraphic position | Material | Notes |
| Caraphlebia | C. antartica | Carapace Nunatak | wings | A dragonfly | |
| Uralonympha | U. sehopfi | Carapace Nunatak | A nearly complete specimen | A stonefly nymph | |
| Coleoptera | Indeterminate | Carapace Nunatak | Wing | Unnamed and non compared |
Ostracoda
Fungi
Plants
One of the best preserved fossil flora of the Antarctic. Spores are Know| Genus | Species | Location | Stratigraphic position | Material | Notes |
| Nothodacrium | N. warreni | Carapace Nunatak | Specimens | A member of the family Podocarpaceae | |
| Masculostrobus | M. warrenii | Carapace Nunatak | Specimens | A member of the family Podocarpaceae | |
| Brachyphyllum | Indeterminate | Carapace Nunatak | Specimens | A member of the Coniferales | |
| Classostrobus | C. elliotii | Carapace Nunatak | Specimens | A member of the Cheirolepidiaceae | |
| Chimaerostrobus | C. minutus | Carapace Nunatak | Specimens | An indeterminate conifer pollen cone | |
| Polyphacelus | P. stormensis | Carapace Nunatak | Specimens | Fern petioles | |
| Zamites | Indeterminate | Carapace Nunatak | Specimens | Spermatophyta incertae sedis |