Crude Oil Deposits in Oceans and the Role of Photosynthesis Crude oil is a black-brown liquid that is found in the earth’s crust which contains majorly of hydrocarbons (50-90% in composition), organic compounds such as, nitrogen, oxygen and sulphur (about 6-10%) and metals like copper and iron taking less than 1% of the composition total(oilprice.com, 2009). It is formed as a consequence of a process that involves the death of algae, planktons and other forms of marine life which deposit at the sea floor. This piling up of partially decomposed or decomposing organic material is covered by layers of mud, sediments and silt resulting to the formation of strata over the years. Due the pressure exerted on this matter by mass of water above, it becomes compacted leading to the formation of a substance known as kerogen