Named after Wolfgang Märker, owner and director of the Märker cement factory at Harburg, located on the edge of the Ries {see planet  (4327)} impact crater, Germany. Märker and his forebears have maintained a long tradition of support for geological research in one of the world’s best studied impact craters. Märker’s responsible interest in the Ries geology and his involvement in the production of special cement from local impact breccias has kept quarries in operation that have yielded invaluable information about the Ries crater. This has been of fundamental importance for research opportunities in the field of impact cratering. (M 18140) _ _.