High Quality Content by WIKIPEDIA articles! Clarence P. Cazalot, Junior (born 1950) is president and chief executive of the Houston-based Marathon Oil Corporation. Since he took over control of the company in 2002, Marathon has expanded abroad with investments in the nascent gas industry of Equatorial Guinea and oil in Gabon, Libya and Norway. Its upstream earnings from overseas projects have been tripled and Marathon is beginning to sell off the smaller assets.