Theory question 303
Rocks(a) What is a metamorphic rock? (b) List two examples of metamorphic rocks (c) Outline five differences between a sedimentary rock and a metamorphic rock
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(a) A metamorphic rock is a rock formed when an existing igneous or sedimentary rock is changed in form and composition by great heat and/or pressure.
(b) Marble; slate; gneiss; schist; quartzite; graphite.
(c) Sedimentary rocks form from deposited sediments, metamorphic from existing rocks changed by heat/pressure; sedimentary are stratified, metamorphic foliated or banded; sedimentary may contain fossils, metamorphic rarely; sedimentary are usually soft and porous, metamorphic hard and compact; sedimentary form at or near the surface, metamorphic deep in the crust or near intrusions; sedimentary are not crystalline, metamorphic often crystalline.
Compare both rocks in each point.