| Popis: |
The crust across each margin of the Labrador Sea, a conjugate rift margin pair, consists of three well-defined zones: thinned continental crust, 70–80-km-wide transitional crust, and oceanic crust. The transition zone is characterized by a low-velocity upper crust (4–5 km/s) underlain by a 6.4–7.7 km/s layer. We propose that the lower layer is serpentinized upper mantle; it is less likely to be gabbroic igneous lower crust. The low-velocity upper crust may be either an oceanic basaltic layer or very thin ( |
