February 4- sedimentary rocks

February 4- sedimentary rocks - GEO 1401 Notes Test 1...

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GEO 1401 Notes Test 1 February 4, 2008 Sedimentary Rocks More sedimentary structures 4. Mud cracks - form when wet mud dries out, it shrinks and pulls apart, creating cracks. 5. Cross beds - inclined layers within beds a. Forms as ripples or dunes migrate. Wind b. Sand grains tumble down the down-wind face of the sand dune and form inclined layers. Can tell direction that wind is blowing. c. Cross beds tell us that a current was moving sediment 6. Sedimentary rocks have porocity - empty space that can be occupied by a fluid a. Can be occupied by water (water well), oil b. Water and oil are most often recovered from sedimentary rocks Metamorphic Rocks Metamorphic rock - rocks that have formed in the solid state in response to changes in temperature and pressure Parent rock - rock that recrystallizes (changes in the shape and orientation of crystals) Classification of metamorphic rocks- the presence or absence of a foliation Foliation - planar feature caused by parallel alignment of platy minerals or banding (layering). ( why people want them as their countertops) 2 groups of metamorphic rocks Foliated metamorphic rocks Slate- fine grained Excellent foliation- slaty cleavage Breaks along parallel planes Forms under Low grade metamorphism (doesn’t have to be hot or have very much pressure) Parent rock- shale Used in slate roofing Schist - coarse grained foliated metamorphic rock Higher temp and pressure Parallel alignment of micas Parent rock is a slate Ex: Mica schist rock Gneiss - croarse grained banded metamorphic rock High grade metamorphism Parent rock is a schist Represent extreme high temperature and pressure
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Non Foliated metamorphic rock
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This note was uploaded on 04/30/2008 for the course GEO 1401 taught by Professor Dworkin during the Spring '08 term at Baylor.

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February 4- sedimentary rocks - GEO 1401 Notes Test 1...

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