Lecture 6-7 Sedimentary and Metamorphic Rocks. Part 1 Sedimentary Rocks. Kyanite, Sillimanite, and Andalucite. What is a sedimentary rock?. Sedimentary rocks result from mechanical and chemical weathering Comprise ~ 5% of Earth’s upper crust About 75% of rocks at surface
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Kyanite, Sillimanite, and Andalucite
Most common sedimentary rock
2. Larger mudrock grains called silts
silt-sized particles .004-.063 mm
Gritty grains can be felt
Character of detrital sediments depends on time, distance, and energy. For example, in streams:
Particles are large and
irregular, and consist of
a variety of lithologies,
including the least
Particles are mid-sized
and of intermediate
sphericity, and include
resistant and nonresistant
Particles are small and
nearly spherical, and
consist mainly of the
most resistant lithologies,
such as quartz.
in ancient sand dunes
Frosted Grains, well sorted
Metamorphism and Metamorphic Rocks
– Talc (lubricant, insulators, refractories), Corundum, Garnet (abrasives), Kyanite (ceramics), Micas (insulators), Chrysotile (“asbestos” for fireproofing), etc., etc.
Metamorphismoccurs between about 10 and 50 km of depth
Source:Kenneth Murray/Photo Researchers Inc.
3. Parent rock
Produced mostly by local heat source
Notice Quartz and Feldspars are useless
Note Quartz and Feldspar are not index minerals: Why?
Some index minerals give us temperature info
Polymorphs of Al2SiO5
Mapped by index minerals
Increasing pressure and temperature
Chlorite and muscovite
Metamorphism of a mudstone
Increasing Directed Pressure and increasing Temps
Garnets are abrasives, long lasting bearings, and jewels
Part igneous, part metamorphic