Can anybody explain the question number 8 on the practice quiz for me, please? thank you.

-- Mei-Ling Chen (mchen@oswego.edu), February 27, 2001

Answers

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 (donnabollmann@hotmail.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 (peter@mattbrothers.com), October 08, 2004.