Fig. 1From: Distribution, morphology, and morphometry of circular mounds in the elongated basin of northern Terra Sirenum, MarsColor-coded topographic map of the northern part of Terra Sirenum. Base map is the gridded MOLA topography data (512 pixels/degree) overlying the corresponding MOLA-shaded relief map (Smith et al. 2001) in simple cylindrical projection. Regional structures, interpreted by Tanaka et al. (2014), are drawn as solid black lines with symbols. A white rectangle indicates the location of Fig. 2. The inset shows the location of the study area on MOLA global topography map rendered with the Google EarthBack to article page