摘要
Seismic and magnetotelluric field campaigns carried out across the Himalaya and the Qinghai-Tibetan Plateau show mid-crustal low resistivity and low-velocity zones.Whether these anomalies indicate that there are molten zones present in the Tibet crust is a focus of geophysical and petrological research.Previous interpretations of MT data to infer melt fractions are often based on presumed electrical conductivity values of partial melt.Temperature,pressure,especially water content in the melt influences the melt conductivity and affects the inferred melt fractions in areas of Tibet.So accurate constraints are essential.In addition,a variety of equations have been proposed to model the conductivity of partially molten rocks in Tibetan crust.However,different rock electrical models relate to different lithological parameters of rocks.So we need to find an appropriate rock electrical model that can apply to Tibet crust.In this study,we use a general electrical conductivity model developed by the global fitting of experimental data in previous study and set up a range of temperature,pressure,and water content for five regions in Tibet.What’s more,using three widely used rock electrical models to figure out corresponding melt fractions in areas of Tibet.We find the most applicable rock electrical model in this region and know better about the distribution and morphology of medium in Tibetan crust.
