Stratigraphic correlations presented here for the ductilely deformed and metamorphosed rocks exposed in the Shadow Mountains indicate that they formed on the North American continental margin and are not exotic or significantly displaced from their site of origin. These strata represent a depositional history that spans Late Proterozoic and Paleozoic passive margin development, late Paleozoic t...

Geology is a complex, semantically rich domain involving the interpretation of geological maps as external visualizations. Geological maps are complex in particular because 3-dimensional features must be inferred from 2-dimensional representations depicted by differing line types and weights. Modeling building, as an internal mental activity, is also required in order to achieve deep understand...

Eoarchean [3.6 to 4.0 billion years ago (Ga)] tonalite-trondhjemite-granodiorite (TTG) is the major component of Earth's oldest remnant continental crust, thereby holding the key to understanding how continental crust originated and when plate tectonics started in the early Earth. TTGs are mostly generated by partial melting of hydrated mafic rocks at different depths, but whether this requires...

Plate tectonics, a special class of mantle convection so far observed only on the Earth, is responsible for a vast array of geological processes, from the generation of continental crust to the modulation of atmospheric composition. Whereas conditions for its operation are still debated, the minimum requirement is generally thought that surface plates become denser than the underlying asthenosp...

The habitable zones of main sequence stars have traditionally been defined as the range of orbits that intercept the appropriate amount of stellar flux to permit surface water on a planet. Terrestrial exoplanets discovered to orbit M stars in these zones, which are close-in due to decreased stellar luminosity, may also undergo significant tidal heating. Tidal heating may span a wide range for t...

The calculation of the uncertainty in an estimated rotation requires a parametrization of the rotation group; that is, a unique mapping of the rotation group to a point in 3-D Euclidean space, R3. Numerous parametrizations of a rotation exist, including: (1) the latitude and longitude of the axis of rotation and the angle of rotation; (2) a representation as a Cartesian vector with length equal...