Biomarkers are any of a suite of complex organic compounds composed of carbon, hydrogen and other elements such as oxygen,nitrogen and sulfur, which are found in crude oils, bitumens and a petroleum

Petroleum

Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...

 source rock

Source rock

In petroleum geology, source rock refers to rocks from which hydrocarbons have been generated or are capable of being generated. They form one of the necessary elements of a working petroleum system. They are organic-rich sediments that may have been deposited in a variety of environments including...

 and eventually show simplification in molecular structure from the parent organic molecules found in all living organisms. Essentially, they are complex carbon-based molecules derived from formerly living organisms. Biomarker compounds are typically analyzed using gas chromatography and mass spectrometry

Mass spectrometry

Mass spectrometry is an analytical technique that measures the mass-to-charge ratio of charged particles.It is used for determining masses of particles, for determining the elemental composition of a sample or molecule, and for elucidating the chemical structures of molecules, such as peptides and...

. Some examples of biomarkers found in petroleum are pristane

Pristane

Pristane is a natural saturated terpenoid alkane obtained primarily from shark liver oil, from which its name is derived . It is also found in mineral oil and some foods...

, phytane

Phytane

Phytane is a diterpenoid alkane. In contrast to pristane, which is formed from the decarboxylation of phytol, it has one extra carbon.Phytanyl is the corresponding substituent. Phytanyl groups are frequently found in phospholipids in membranes of thermophilic Archaea...

, sterane

Sterane

Steranes are a class of 4-cyclic compounds derived from steroids or sterols via diagenetic and catagenetic degradation and saturation. Steranes have an androstane skeleton with a side chain at carbon C-17. The sterane structure constitutes the core of all sterols. Steranes are sometimes used as...

s, triterpanes

Oleanane

Oleanane is a natural triterpene. It forms the central core for a wide variety of chemical compounds found in flowering plants which are referred to collectively as oleanane triterpenes.Some oleanane triterpenes have a suppressing effect on insect pests...

 and porphyrin

Porphyrin

Porphyrins are a group of organic compounds, many naturally occurring. One of the best-known porphyrins is heme, the pigment in red blood cells; heme is a cofactor of the protein hemoglobin. Porphyrins are heterocyclic macrocycles composed of four modified pyrrole subunits interconnected at...

. Geologists and Geochemists utilize biomarkers traces found in crude oils and their related source rock

Source rock

In petroleum geology, source rock refers to rocks from which hydrocarbons have been generated or are capable of being generated. They form one of the necessary elements of a working petroleum system. They are organic-rich sediments that may have been deposited in a variety of environments including...

 to unravel the stratigraphic origin and migration pathways of presently existing petroleum

Petroleum

Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...

deposits.