High heat flow at the SW passive margin of the Gulf of California

Abstract

AbstractNew high heat flow data confirm the presence of a heat source in the passive margin of the southern Baja California Peninsula that is not linked with volcanic activity. The high heat discharge is spatially associated with low seismic velocity, crustal thinning, intense seismic activity, documented local extension, shallow Curie Point Depth and silica geothermometer temperatures above 100°C. The highly oblique rifting regime in the centre of the Gulf of California generates a transtensional setting conducive to local extension in its southwest margin. Similar high heat flow in a rifted margin has been reported only in the Gulf of Aden that is also an obliquely spreading ridge. The intense heat discharge, with heat flow values as high as 613 mW/m2, indicates the presence of a heat source consistent with mantle upwelling. Heat transfer calculations indicate that the heat source emplacement would be at most 2 Ma old.