Dolomite is formed by the action of magnesian rich sea water

dolomite-is-formed-by-the-action-of-magnesian-rich-sea-water

Dolomite is formed by the action of magnesian rich sea water on which deposit?

A. Limestone

B. Sandstone

C. Granite

D. Basalt

This question was addressed to me in exam.

My doubt stems from Formation and Descriptive Study of Minerals topic in portion The Study of Minerals of Engineering Geology

Right choice is A. Limestone

Easy explanation: As a rock constituent, dolomite is believed to have been formed by the action of magnesian rich sea water on original limestone deposit. This process is called in petrology dolomitization.