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The Yellowstone hotspot resulted from interaction of a mantle plume with the overriding North America plate highly modifying the lithosphere by magmatic-tectonic processes and producing the 17 Ma Yellowstone-Snake River Plain (YSRP) volcanic system. The accessibility of the YSRP has allowed largescale geophysical experiments to seismically image the hotspot and to evaluate its kinematic and dynamic properties using geodetic measurements. Tomography reveals a Yellowstone crustal magma body with 8-15% melt that is fed by an upper-mantle plume extending from 80 km to 660 km deep and tilting 60º west. Contemporary deformation of the Yellowstone caldera is dominated by SW-extension at up to ~3 mm/yr, a fourth of the total Basin-Range opening rate, but with superimposed volcanic uplift and subsidence at decade scales, averaging ~2 cm/yr and unprecedented caldera uplift from 2004-2008 at up to 7 cm/yr. Convection models reveal eastward upper-mantle flow beneath Yellowstone at relatively high rates of 5 cm/yr and opposite in direction to the overriding N. American Plate. This strong flow deflects the ascending plume melt into a tilted configuration, i.e., the plume is caught in a mantle "wind". Dynamic models of the Yellowstone plume revealed relatively low excess temperatures, up to 120°K, with up to 1.5% melt, properties consistent with a weak buoyancy flux of ~0.25 Mg/s. The flux is several times smaller than for oceanic plumes, but it produced a ~600-km wide topographic ~300-m high swell. Employing the plume-geometry we extrapolated the location of the Yellowstone mantle-source southwestward to its initial position at 17 million years beneath eastern Oregon and the southern edge of the LIP Columbia Plateau basalt field suggesting a common origin. Our model suggests that the original plume head rose vertically behind the subducting Juan de Fuca plate, but at ~12 Ma it lost the protection of the subducting plate and encountered cooler, thicker continental lithosphere and became affected by the eastward upper-mantle flow. Regionally, excess gravitation potential energy of the swell drives the SW motion of the YSRP lithosphere that becomes part of a general clockwise rotation pattern of intraplate western U.S. tectonism. Our models thus demonstrate that plume-plate processes of the YSRP have "continentalized" oceanic lithosphere enhancing intraplate extension and highly modifying topography, deep into the continental interior. Our results demonstrate that the dynamic properties of the Yellowstone hotspot deserved its recognition as a "window into the Earth's interior". JVGR

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