EARTHSC 1G03 Study Guide - Midterm Guide: Magma Chamber, Mantle Plume, Continental Crust

• School: McMaster University
• Department: Earth Sciences
• Course: EARTHSC 1G03
• Professor: Maureen Padden

Document Summary

The angle between the direction that a compass needle points and a line of longitude at a given location is the magnetic declination: paleomagnetism- the magnetic elds of ancient rocks indicate the orientation of the magnetic. Negative anomalies form when sea- oor rock has polarity that is opposite to the present. As the magma cools, it turns into a mush of crystals. Intrusions underground juxtapose igneous rock with wall rock. Tabular intrusions (sills and dikes) are wall-like intrusions. Ux melting due to release of uids from subjecting slabs produces is probably due to decompression at the top of a mantle plume. Decompression of rising asthenosphere also triggers melting beneath rifts and mid ocean ridges. injection of hot mantle-derived magma into the crust at rifts and convergent margins causes melting of the crust. Chapter five: basaltic (ma c) lava ows long distances and has low viscosity. pahoehoe is smooth, a"a" is rubbly and sharp.