correlation of rocks

• Correlation or rocks is the matching of rocks, like beds of sedimentary rocks in different geographical locations. 
• Boreholes are used to sample the rock. The closer boreholes are drilled together the more information they provide and the more money they cost. 
• Biostratigraphic correlation - zone fossil content regardless of the rock type 
• Lithostratigraphic correlation - physical characteristics of the rock. 
• Chronostratigraphic correlation - matching events over large areas.