Dansirit Formation

Dansirit Formation
Stratigraphic range: Aalenian-Bajocian ~175–165  Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Unit of	Shemshak Group
Underlies	Dalichai Formation
Overlies	Fillzamin & Shirindasht Formations
Thickness	over 200 metres (660 ft)
Lithology
Primary	Sandstone
Other	Shale, siltstone, Coal
Location
Coordinates	36°12′N51°42′E / 36.2°N 51.7°E / 36.2; 51.7
Approximate paleocoordinates	29°06′N59°48′E / 29.1°N 59.8°E / 29.1; 59.8
Region	Mazandaran
Country	Iran
Extent	Alborz Mountains
Dansirit Formation (Iran)

The Dansirit Formation is a geological formation in Iran. It is Middle Jurassic in age, dating from the Aalenian to Bajocian.

Fossils

The fossils of Dansirit Formation mainly include plant fossils and dinosaur footprints ^{[1] [2] [3]}

Plant fossils

Plant fossils of the Dansirit Formation mostly include Filicales, Bennettitales, Cycadales, Corystospermales, Caytoniales, Czekanowskiales, Ginkgoales and Pinales. Filicophyta, Coniferales, Bennetitales and Equisetales dominate the flora, which indicates the deposition of this formation in relatively tropical and rainy environments in islands, deltas and river banks. ^{[1] [4]}

Dinosaur footprints

The dinosaur footprints of this formation in Mazandaran province include theropods with an average length of about 2 meters, small two-toed Deinonychosaurs, relatively giant sauropods about 9 meters long, and small two-legged ornithopods. These works are limited to footprints and dinosaur fossils have not been reported in this formation. ^{[3] [2]}

Description

It is part of the Shemshak Group, a Late Triassic to Callovian set of coal bearing largely fluvio-lacustrine sediments up to 4000 metres thick located within the Alborz Mountains. ^[4] The outcrop of sediments is strongly controlled by numerous fault structures in the region. The formation predominantly consists of sandstone, with subordinate siltstone and shale. Dinosaur tracks are known from the formation, including sauropods, and tridactyl ^[3] and didactyl theropods. ^[2] A diverse fossil flora is also known from the formation. ^[1]

See also

Shemshak Group

References

1. Vaez-Javadi, Fatemeh (March 2011). "Middle Jurassic flora from the Dansirit Formation of the Shemshak Group, Alborz, north Iran". Alcheringa: An Australasian Journal of Palaeontology. 35 (1): 77–102. Bibcode:2011Alch...35...77V. doi:10.1080/03115518.2010.489424. ISSN   0311-5518.
2. Xing, Lida; Abbassi, Nasrollah; Lockley, Martin G. (2018-11-17). "Enigmatic didactyl tracks from the Jurassic of Iran". Historical Biology. 30 (8): 1132–1138. Bibcode:2018HBio...30.1132X. doi:10.1080/08912963.2017.1339700. ISSN   0891-2963.
3. Abbassi, Nasrollah; Madanipour, Saeed (2014-04-01). "Dinosaur tracks from the Jurassic Shemshak Group in the Central Alborz Mountains (Northern Iran)". Geologica Carpathica. 65 (2): 99–115. Bibcode:2014GCarp..65...99A. doi: 10.2478/geoca-2014-0007 . ISSN   1336-8052.
4. Fürsich, Franz Theodor; Wilmsen, Markus; Seyed-Emami, Kazem; Majidifard, Mahmoud Reza (2009). "Lithostratigraphy of the Upper Triassic–Middle Jurassic Shemshak Group of Northern Iran". Geological Society, London, Special Publications. 312 (1): 129–160. Bibcode:2009GSLSP.312..129F. doi:10.1144/SP312.6. ISSN   0305-8719.