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Regions with high electrical conductivities in subduction zones have attracted a great deal of attention. Determining the exact origin of these anomalies could provide critical information about the water storage and cycling processes during subduction. Antigorite is the most important hydrous mineral within deep subduction zones. The dehydration of antigorite is believed to cause high-conductivity anomalies. To date, the effects of dehydration on the electrical conductivity of antigorite remain poorly understood. Here, we report new measurements of the electrical conductivity of both natural and hot-pressed antigorite at pressures of 4 and 3 GPa, respectively, and at temperatures reaching 1073 K. We observed significantly enhanced conductivities when the antigorite was heated to temperatures beyond its thermodynamic stability field. Sharp increases in the electrical conductivity occurred at approximately 848 and 898 K following the decomposition of antigorite to forsterite, enstatite and aqueous fluids. High electrical conductivities reaching 1 S/m can be explained by the presence of an interconnected network of conductive aqueous fluids. Based on these results for the electrical conductivity of antigorite, we conclude that high-conductivity regions associated with subduction zones can be attributed to dehydration-induced fluids and the formation of interconnected networks of aqueous fluids during the dehydration of antigorite.

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The dehydration of hydrous minerals is one of the causes of high-conductivity anomalies in subduction zones. To determine the origin of these anomalies, the trade-off between the dehydration and conduction mechanisms of hydrous minerals at high pressures and temperatures should be clarified. Talc is a typical hydrous mineral in hot subduction zones, and previous studies may have underestimated its contribution to high-conductivity anomalies. We report the new electrical conductivity results for talc, which were measured at 1.0-4.0 GPa and 523-1293 K using impedance spectroscopy. The pressure effect on conductivity of talc is obvious in the different heating stages. The pressure decreased the conductivity prior to dehydration and remarkably increased the conductivity during dehydration. A sharp conductivity increase was observed beyond the dehydration temperature, and the maximum conductivity was 0.1 S/m. The increase in conductivity associated with a high activation energy of 284.5 ± 11.8 kJ/mol and an activation volume of −6.2 ± 0.6 cm 3 /mol was attributed to an inhomogeneous dehydration model involving cation migration. The talc dehydration temperatures at different pressures derived from the conductivity inflection points are 1023-1093 K. The increased electrical conductivity produced by talc ongoing dehydration provides an explanation for the high-conductivity anomalies observed at deep depths in hot subduction zone. The silica-rich fluid released by talc may contribute to the silica deposition in plate interface and induce the high-conductivity anomalies observed at shallow depths in the hot subduction zones. Plain Language Summary Geophysical observations have revealed many anomalously high electrical conductivity regions in subduction zones. The dehydration of hydrous minerals may induce high-conductivity anomalies in subduction zones, but how the dehydration affects the electrical conductivity remains unclear. We report new results of high-pressure conductivity measurements on talc at 1.0-4.0 GPa and up to 1293 K. We found a sharp conductivity increase above the dehydration temperature, and the maximum conductivity was~0.1 S/m. We also found the increase in conductivity was attributed to cations migration. The experimental results were analyzed to interpret the geophysical observations in subduction zones. We conclude that dehydration provides an explanation for the high-conductivity anomalies observed in some hot subduction zones. These results will enhance our ability to figure out the distribution of hydrous minerals in slabs through interpretation of high-conductivity anomalies in subduction zones.

Limited therapeutic interventions are clinically available for treating aggressive endometrial cancer (EC). Therefore, effective therapies are urgently required. Therefore, the present study investigated the role of ∆9-tetrahydrocannabinol (THC), which is reported to impact proliferative and migratory activities during impairment of cancer progression. In the present study, cell migration in response to THC was measured using transwell assays. Using western blot analysis, the levels of cannabinoid receptors in EC tissues were detected and pathways leading to the inhibition of cell migration by THC on human EC cells were determined. Results suggested that cannabinoid receptors were highly expressed in EC tissues. Furthermore, THC inhibited EC cell viability and motility by inhibiting epithelial-mesenchymal transition (EMT) and downregulating matrix metalloproteinase-9 (MMP-9) gene expression in aggressive human EC cells. The results have the potential to promote the development of novel compounds for the treatment of EC metastasis. The presnet findings suggest that THC may inhibit human EC cell migration through regulating EMT and MMP-9 pathways.