Variation in styles of rifting in the Gulf of California

Results from the PESCADOR seismic experiment in the Gulf of California provide new insight into rifting — the process that ruptures continents and forms new ocean basins. Unpredicted variations in magmatic activity in continental rifts are commonly attributed to variations in mantle temperature, but such thermal variations tend to occur over large length scales. The new results reveal large differences in rifting style and magmatism over short lateral distances. This suggests that the observed range in magmatism is caused not by variation in temperature, but rather by variability in mantle composition and fertility — the intrinsic capacity of the underlying mantle to produce melt.