Structural controls on the location of hydrothermal activity at the inside corner revealed by stress state

Abstract

The increased hydrothermal activity at the inside corners is interpreted to be controlled by the high-permeability detachment faults at mid-ocean ridges. Paradoxically, no hydrothermal activity is confirmed to be located at the detachment terminations, where the permeability is theoretically maximal. Here, we use a numerical model to investigate the stress state of the Longqi hydrothermal field and Trans‐Atlantic Geotraverse (TAG) hydrothermal field, which are both located on the hanging wall of a detachment fault rather than at detachment terminations. Our results show that the maximum horizontal stress SHmax at the inside corner is deviated from the observed spreading direction by more than 45°. Meanwhile, shear strain is much higher at the insider corner and the distributions of maximal shear strain is consistent with locations of hydrothermal field. We speculate that regional stress rotation and shear strain enhance the regional permeability of the shallow crust, facilitate hydrothermal circulation on the hanging wall and therefore control the location of the hydrothermal field. Our model provides a potential mechanism for the location of the hydrothermal activity in similar geological settings and therefore provides an important constrain for the exploration of seafloor massive sulfide deposits in the future.