The ITRESC Method for Basement Morphology Modelling: the Case of Yucca Flat (Nevada)

The Yucca Flat is located in the Basin and Range province and it was one of four major nuclear test regions of the Nevada National Security Site. In the past decades, many gravity stations were acquired in this site, along with an unusually high number of boreholes. This dataset is here modelled by the ITRESC method, based on the building of a depth-gravity relationship, for which a set of depth constraints (i.e., estimates of the depth to basement at some locations) are needed. The main difference between this method and most of the approaches commonly used to model the basement morphology is that the density function is not required as an input, but it is instead a product of the interpretation process. The resulting model displays many details more than previous interpretations. The maximum thickness of sediments is found to be about 1.2 km. Information about the presence of horizontal density contrasts in the sediment filling, a complexity that the method cannot take into account, can be obtained from the misfit between the basement model and the borehole depths to basement.