Name: Karatau Location: South Kazakhstan Age: Jurassic

Geological setting and age

These rocks are believed to have formed in two different environments:

1. In the early-middle Jurassic, the sediments were deposited on a flood plain and there were also several rivers flowing in the area.

2. In the late Jurassic, a lake formed and the flood plain disappeared. The lake contained either fresh or slightly salty water and the rocks that formed here are where the fossils are found.

The Karatau fossils are of land animals and they have somehow ended up in a lake and been fossilized. The lake has been named Lake Karatau, and the rocks are very fine grained carbonates, dolomites, marls and shales.

The plant fossils found here include ferns, seed ferns, conifers, cycads and gingkos.
Wide ranges of vertebrate and invertebrate fossils have also been found. Fish are the most common, but turtles, pterosaurs, insects, crocodiles, a lizard, a salamander and a feather fragment have been found as well, indicating that the environment was suitable for several different types of animal life.