Maruta's exit will coincide with the arrival of new CEO Roman Deniskin.
The company only said Maruta had decided to "seek other opportunities".
He is also a director, and his resignation coincides with the appointment of Adrian Coates to the board.
The former HSBC banker has served on the Polyus Gold (LN:POLY) and Kazakhgold boards.
Petropavlovsk chairman Ian Ashby said Coates would also be sent to subsidiary iron ore company IRC Ltd (HK:01029).
"We believe Adrian's experience will be very valuable and intend to recommend to IRC Limited's board of directors that he should also become a member of its board," he said.