question on the practice quiz of Chapter 5greenspun.com : LUSENET : Introductory Geology, Oswego State : One Thread
Can anybody explain the question number 8 on the practice quiz for me, please? thank you.
-- Mei-Ling Chen (firstname.lastname@example.org), February 27, 2001
The reason why basalt is the primarily found rock along the mid-ocean ridge is because mid-ocean ridges are volcanic mountains on the ocean floor which spew magma that consists of mostly basalt.
-- DonnaMarie Bollmann (email@example.com), February 27, 2001.
Basalt is rock with high ferro-magnesian content. Oceanic plates are distinguished from continental plates by being more dense, due to this chemical makeup. Basalt is a common extrusive form of magma with this sort of composition and thus the expected rock type at mid- ocean spreading centers.
-- peter matt (firstname.lastname@example.org), October 08, 2004.