What general environmental condition is represented by this

What general environmental condition is represented by this assemblage - marine or nonmarine? (b) Based on the fossil assemblage, describe the energy of each environment (e.g. turbulent wave environment, calm offshore or lagoon) Shale: Sandstone: Limestone: (c) Which unit shows the greatest biological diversity?

Solution

b. Shale - Shale is said to be deposited by the lower to outer shelf below wave base under low energy conditions. Black shale containing fossil plants represents swamp environments.

Sandstone - Siliclastic carbonate sandstone contains deposition from shallow marine with high energy near shore depositional environment . Pebbly sand stone also contains high energy environments of the shore face. The cross bed sandstone which is deposited in the upper part also is deposited by high energy environment like storm.

Limestone - limestone units of packstone - rudstone are high energy deposits whereas wackestone - floatstone are deposits of low energy below wave base. Limestone composed of float stone to rug stone deposition indicates its transition from low to high energy deposition. Sandy lime stone contains deposits of high energy.

c. Limestone contains calcium carbonate and it gives the property to the rock for identification. It has greater biodiversity compared to other types of rocks.