CentralNotice From Wikipedia, the free encyclopedia Jump to: navigation , search For mass concentration in chemistry, see Mass concentration (chemistry) . Topography (top) and corresponding gravity (bottom) signal of lunar Mare Smythii containing a significant mascon. In astronomy and astrophysics , a mass concentration (or mascon ) is a region of a planet or moon's crust that contains a large positive gravitational anomaly . In general, the word "mascon" can be used as a noun to describe an excess distribution of mass on or beneath the surface of an astronomical body (with respect to some suitable average), such as is found around Hawaii on Earth. [1] However, this term is most often used to describe a geologic structure that has a positive gravitational anomaly associated with a feature (e.g. depressed basin) that might otherwise have been expected to have a n...