As compared to subaerial basaltic lavas,submarine basaltic lavas differ in that they ____________.
A) always produce violent pyroclastic debris flows
B) produce large crystals of pyroxene and plagioclase
C) form pillow-like mounds because they cannot flow as far from their source
D) all of the above

Question

Quizplus · Accepted Answer

Submarine basaltic lavas form pillow-like mounds due to the rapid cooling of the lava when it comes into contact with cold seawater. Unlike subaerial flows, they cannot flow as far from their source. They may also contain small amounts of pyroclastic debris and may have small crystals of pyroxene and plagioclase, but not to the same extent as subaerial lavas. They do not always produce violent pyroclastic debris flows, so option A is incorrect. Option B is partly right, but does not fully capture the differences between submarine and subaerial basaltic lavas.

As Compared to Subaerial Basaltic Lavas,submarine Basaltic Lavas Differ in That