Sedimentary Rock  Identification

February 9, 2001

This exercise is intended for use with the CSI rock set of 8 specimens. Written by Dr. Alan I. Benimoff and last revised 02/09/01.

Photos by Donald E. Clark, Department of Engineering Science and Physics

Please report any computer program problems to Dr. Alan I. Benimoff E-mail: benimoff@postbox.csi.cuny.edu

Sedimentary Rocks  are classified on the basis of their origin. There are three classses - Detrital, Chemical and Biochemical. The detrital sedimentary rocks have a clastic(fragmental texture) - there are composed of erosional fragments of pre-existing rocks. The Chemical sedimentary rocks formed by evaporation and precipitation of minerals. The Biochemical sedimentary rocks are composed of the remains of organisms.

Determine the texture of the rock:

detrital - rock is composed of eroded fragments of pre-existing rocks .

chemical -usually fine grained .

biochemical - These range from very fine grained to very coarse grained.