Kota formation
The Kota Formation is a lithostratigraphic formation in the Indian Deccan known for its vertebrate fossils. These are continental sedimentary rocks that are dated to the Lower and Middle Jurassic ( Sinemurian to Aalenian ).
Geological framework
The formation belongs to the Pranhita Godavari Basin , which extends as a thin strip from central India in a south-easterly direction to the vicinity of the Bay of Bengal . Below the Kota Formation follows the Dharmaram Formation , which was deposited at the time of the Triassic-Jura border and from which numerous vertebrate finds also originate; In the hanging wall of the formation, meanwhile, follows a discordance , on which the early Cretaceous sediments of the Gangapur formation follow.
Structure and lithology
The formation can be divided into two lithostratigraphic units - the lower and the upper unit. The lower unit is mainly formed by a 15 to 25 meter thick layer of compact, coarse-grained sandstone , which is laterally and vertically replaced by finer sandstones, siltstones and claystones . The upper unit, meanwhile, consists of marl, a 1 to 2 meter thick layer of limestone , as well as alternating sequences of sandstones and iron-containing clay slate.
Presumably the lower unit was deposited by a meandering river system, while the upper unit was mainly deposited by a pigtail system . The intermediate limestone layer was probably deposited within a lake. The lower unit is dated to the Sinemurian to Pliensbachian ; the upper unit on the toarcium up? Aalenium .
Vertebrate fossils
The very original sauropod dinosaurs Barapasaurus and Kotasaurus come from the lower unit . In addition, three mammalian genera were found: Kotatherium from the Kuehneotheriidae family , Indotherium from the Amphilestidae family and Indozostrodon from the Morganucodontidae family .
From the upper unit there are fish such as Lepidotes deccanensis , Paradapedon egertoni , Tetragonolepis oldhami , Pholidophorus kingii , Polidophorus indicus and Indocoelacanthus robustus . Reptiles include the turtle Indochelys , the pterosaurs campylognathoides that Sphenodontier Rebbanasaurus and Godavarisaurus and scales lizard Bharatagama with one. Mammals were with the docodontids Gondtherium and Godavariodon , the amphilestids? Paikasigudodon Yadagiri and the non-allocable genres Dyskritodon , Nakunodon and Trishulotherium detected, further there is the well-known even from the lower unit Indotherium .
Individual evidence
- ↑ a b c d e f Saswati Bandyopadhyay, David D. Gillette, Sanghamitra Ray, Dhurjati P. Sengupta: Osteology of Barapasaurus tagorei (Dinosauria: Sauropoda) from the Early Jurassic of India . In: Palaeontology . tape 53 , no. 3 , 2010, section Geological Setting and Table 3, p. 537-539 , doi : 10.1111 / j.1475-4983.2010.00933.x ( [1] ).