Sedimentological and structural measurements and rock samples for radiometric dating of the Swanson Group and Ford Granodiorite of the Ford Ranges, Marie Byrd Land, West Antarctica

The purpose of the expedition was to examine in detail the pre-Cenozoic geology of the Ford Ranges which comprise the main area of exposed rock in western Marie Byrd Land and the type area of two of the four major rock groups, the Swanson Group and the Ford Granodiorite. Sites visited and examined include Mt Morgan, Wells Ridge, Ranney Nunatuk, Mt Crabtree in Swanson Mountains, Mt Passel, Mt Richardson in the Fosdick Mountains, Breeding Nunatak, Mt Jones in the Clark Mountains, the Mackay Mountains, the Allegheny Mountains, Bailey Ridge and east of Mt Warner. Extensive sedimentological and structural measurements were made on the Swanson Group, the intrusive history of the two granite complexes (Ford Granodiorite and the complex Byrd Coast Granite) were examined and described and rock samples were collected for radiometric dating to determine the time of sedimentation and the time of deformation of the Swanson Group and the times of intrusion and deformation of the Ford and Byrd Coast rock units. From the information obtained, the basement geology of Marie Byrd Land formation was evaluated.