Houston-based Marathon Oil (NYSE:MRO) is about to get a new CFO.

On Tuesday, Marathon announced that after nearly 10 years at her post, Chief Financial Officer Janet F. Clark intends to step down on Sept. 3, and to retire from the company entirely on Oct. 1. Replacing her will be new hire John R. Sult, a former executive at El Paso Corp., and currently a director of Dynegy.

Sult brings nearly a decade of experience at the highest levels of the oil and gas industry, having served as CFO at El Paso Corp., and before that, as controller at Halliburton Energy Services. Prior to joining the industry, he worked at Arthur Andersen for more than 20 years.