Answer:
Core samples are the samples of rocks that are obtained from the sub-surface by drilling. It is an expensive method to acquire these rocks. But these core samples are very useful for a geologist. They give the following pieces of information-
(1) It is used to study the subsurface lithology.
(2) The age to which these rocks belongs can be known.
(3) Porosity as well as the permeability of the rocks can be measured.
(4) They are used to determine the probable amount of productivity in oil in that rock.
(5) The core samples are also collected from different nearby places within a particular region in order to determine the extent to which the probable oil, petroleum, natural gas, and other valuable minerals are present.