Marsh & McLennan Companies Inc. is putting a veteran of corporate turbulence in charge of its Mercer Human Resource Consulting unit.

Marsh & McLennan has promoted M. Michele Burns to succeed Michael Caulfield as chairman of Mercer.

Caulfield is retiring, Marsh & McLennan says.

Burns began working for Marsh & McLennan as a chief financial officer in March.

Before that, Burns was the CFO and chief restructuring officer at Mirant Corp., Atlanta, a power-generating company that filed for bankruptcy court protection in 2003.

From 2000 to 2003, Burns was chief financial officer at Delta Air Lines Inc., Atlanta.

Burns has a bachelor’s degree in business administration and a master’s degree in accountancy from the University of Georgia. She serves on the boards of Wal-Mart Stores Inc., Bentonville, Ark., and Cisco Systems Inc., San Jose, Calif.

“I look forward to leading Mercer Human Resource Consulting during this exciting time in the company’s history,” Burns says in a statement about her new post.

Marsh & McLennan is promoting Matthew Bartley, the company’s treasurer, to succeed Burns as CFO.

Bartley has a bachelor’s degree from the University of Pennsylvania, a master’s degree from Yale University, and a law degree from Columbia University.