REGIONAL GRAVITY ANALYSIS OF THE YELLOWSTONE CALDERA, WYOMING

The Yellowstone volcanic complex (YVC) of northwestern Wyoming is the youngest part of a magmatic system that has propagated northeastward along the path of the eastern Snake River Plain starting at approximately 2 Ma. This northeastward propagation has been widely interpreted to be the result of a continental hotspot generated by the upwelling tail of a deep mantle plume or by edge convection. The YVC is composed of three calderas that formed between 0.6 to 2.1 Ma with the youngest occupying the center of Yellowstone National Park. There have been numerous seismic tomographic, regional gravity and long period magnetotelluric investigations that have studied the deeper crustal and upper mantle structures but few have concentrated on the upper crustal structure. To investigate the upper crustal structure of the latest Yellowstone caldera, approximately 2000 new gravity stations were collected. These data were merged with existing data to create a series of isostatic, decompensative, residual and derivative gravity anomaly maps. In conjunction with two-dimensional forward modeling, the structure and location of the caldera system will be investigated.