SourceRock
organic‐rich sediments
Deposited under airless conditions
Types
of source rocks:
are
classified
from the types of kerogen that
they contain
• source rocks are formed from algal remains deposited under anoxic conditions in deep lakes: they tend
to generate waxy crude
oils when
submitted to thermal stress during deep burial
• Source rocks are formed from marine planktonic remains
preserved
under
anoxic conditions in marine environments: they
produce
both oil and gas when thermally cracked
during
deep burial.
• Source rocks are formed from terrestrial plant material that has been decomposed by
bacteria and fungi under oxic or sub‐oxic conditions: they tend to generate
mostly gas with associated light oils when thermally cracked during deep burial. Most coals and coaly shales
are generally Type 3 source rocks.
Example:
Shale - Limestone
