The seismic low velocity zone just below the base of the lithosphere indicates _
ID: 296717 • Letter: T
Question
The seismic low velocity zone just below the base of the lithosphere indicates _______ .
A) retrograde metamorphism of mantle peridotite
B) partial melting of rocks at those depths
C) intense fracturing of the asthenosphere
D) an unavoidable inaccuracy of measuring sound velocity at those depths
Which one of the following is NOT evidence that supports the theory of plate tectonics?
A. organization of marine magnetic anomalies
B. high heat flow from mid-ocean ridges
C. extinction of dinosaurs at the K-T boundary
D. distribution of earthquakes
Explanation / Answer
1) partial melting of rocks at those depths
this low velocity zone is near the boundary of lithosphere and asthenosphere below 80 to 300Km, and its due to the partial melting of rocks.
2)extinction of dinosaurs at the K-T boundary
extinction of dinosaurs is not related to tectonics but all other factors are strong evidences of plate tectonics