Question

Which of the following is not essential in the formation of black shale units?

Answer 1

Answer:

B. Aerobic bottom water

D. High organic productivity in the overlying oxygen rich water

Explanation:

A Shale is a sedimentary rock usually formed from silt and clay-size mineral. There are different colors of Shale. The Black Shale is formed under anaerobic conditions. This means that oxygen is deficient in the water where the Shale forms.

A little amount of organic materials is required for the formation of Black Shale and because Black Shale is formed in an environment lacking oxygen, an oxygen-rich water would not be necessary for its growth. Sediments are necessary in the formation of Black Shale.