The Kallamedu Formation is a

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

(

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

) geologic

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondary ...

located in the

Ariyalur Ariyalur () is a town and district headquarters of Ariyalur district in the South Indian state of Tamil Nadu and is rich in limestone, surrounded with seven cement factories and two sugar factories. The town is located at a distance of from ...

district of

Tamil Nadu Tamil Nadu (; , TN) is the southernmost States and union territories of India, state of India. The List of states and union territories of India by area, tenth largest Indian state by area and the List of states and union territories of Indi ...

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

that forms part of the Ariyalur Group. It dates to the

of the

Dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

remains and

petrified wood Petrified wood (from Ancient Greek meaning 'rock' or 'stone'; literally 'wood turned into stone'), is the name given to a special type of ''fossilized wood'', the fossilized remains of terrestrial plant, terrestrial vegetation. ''Petrifaction ...

samples are among the known fossils recovered from this formation.Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, Asia)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): ''

The Dinosauria ''The Dinosauria'' is an encyclopedia on dinosaurs, edited by paleontologists David B. Weishampel, Peter Dodson, and Halszka Osmólska. It has been published in two editions by the University of California Press, with the first edition in 1990 ...

'', 2nd, ''Berkeley: University of California Press''. Pp. 593–600. .

Lithology

The Kallamedu Formation likely represented a

fluvial A river is a natural stream of fresh water that flows on land or inside caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of its course if it ru ...

environment. It is composed of

siltstones Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed ...

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

s and

sandstones Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains, cemented together by another mineral. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed o ...

. The high organic carbon content of some of the rocks are consistent with a swamp.https://www.researchgate.net/publication/263426844_SEDIMENTOLOGICAL_STUDIES_OF_KALLAMEDU_FORMATION_IN_ARIYALUR_AREA_TAMIL_NADU_INDIA

Paleofauna

Dinosaurs

Crocodylomorphs

Turtles

Fish

Amphibians

References

{{reflist Geologic groups of Asia Geologic formations of India Upper Cretaceous Series of Asia Maastrichtian Stage Paleontology in India