Mineralogy, Petrology and Geochemistry Flashcards
What are Cataclasites? And how are they formed?
Cataclasites are a cohesive, granular rocks that can be formed from any rock/ consist of any mineral assemblage. They are formed during dynamic metamorphism (at faults or when there is fracturing of the upper crust).
What facies are formed under contact metamorphism?
Albite-Epidote Hornfels
Hornblende Hornfels
Pyroxene Hornfels
Sanadinite
What facies are formed under regional metamorphism?
Zeolite
Prehnite-Pumpellyite
Blueschist
Greenschist
Amphibolite
Granulite
Eclogite
What grade (low, medium or high) of rock does burial metamorphism produce and why?
Low grade because the increased temperature and immense downward pressure causes the rock to recrystalize but not become foliated.
What are common products of impact metamorphism?
• High Pressure minerals (such as coesite or stishovite, both polymorphs of quartz)
• Highly granulated, deformed and shattered rocks
• Shatter cones
What is Bowen’s Reaction Series? What does it describe?
Based on a number of controlled laboratory experiments, it provides a generalized progression of mineral precipitation from a cooling magma, predicting mineral weathering which indicates the stability of minerals at the earths surface.
Minerals at the bottom are the most stable, and the ones at the top, being the quickest to weather- this is because minerals are the most stable at the conditions closest to which they formed under.
What are the 4 types of sedimentary rocks? Give examples of each.
- Clastic/ detrital (consist of clasts or grains)
- Conglomerate
- Sandstone
- Siltstone
- Shale - Biochemical (made from once living creatures- carbonates)
- Fossiliferous
- Oolithic
- Coquina
- Micrite - Organic (altered plant material/ containing Carbon)
- Peat
- Coal - Chemical (evaporates)
- Halite
- Gypsum
How are igneous rocks classified? What are the 7 textures of igneous rocks? And give examples of each texture with the corresponding felsic - mafic composition.
Classified by their cooling history, which dictates their texture.
1. Phaneritic (coarse grained)
- Felsic (Granite)
- Intermediate (Diorite)
- Mafic (Gabbro)
2. Aphaneritic (fine grained matrix)
- Felsic (Rhyolite)
- Intermediate (Andesite)
- Mafic (Basalt)
3. Porphyr
- intermediate (Porphyritic Diorite)
4. Glassy
- Obsidian
5. Vesicular
- Felsic (Pumice)
- Mafic (Scoria, vesicular basalt)
6. Pegmatic
-Felsic (pegmatic granite)
7. Pyroclast
- Felsic (Tuff)
Define diagenesis. What are the types of diagenesis processes?
Any change occurring within sediment during or after its deposition, and after its lithification, NOT INCLUDING weathering (because it is not representative of “normal surface conditions”).
• Compaction/ Cementation (becoming lithified or consolidated)
• Replacement (change in composition of a mineral)
• Crystallization (under normal surface conditions)
What are the different classifications of limestone and how are they linked to the deposition?
Clastic
Made up of calcium carbonate fragments that were deposited in place or were transported elsewhere within the basin in which they formed (predominantly in marine environments)
Non- clastic
Chemically or biologically precipitated calcite or aragonite that have NOT been transported since deposition
Ex. reef limestone (stromatolite)
And name and define/ give examples of the 3 types of facies for sedimentary rocks?
•Lithoclastic (differing texture, mineralogy, grain size, and depositional environment)
•Bioclastic (differing fossil content)
•Cyclothems (repeating sediments that represent the emerg/submergence of land)
And name and define/ give examples of the 7 types of facies for metamorphic rocks?
• Zeolite (Low P, Low T; ex. pyrite)
• Prehnite-pumpellyite (burial below water, shale, mafic rocks, Low P, Low T; ex. calcite and quartz)
• Green-schist (Low - Med P, Med T; chlorite, serpentine, epidote and Muscovite)
• Amphibolite (Med-High P, Med-High T; ex. amphibole and grossular garnet)
• Granulite (deep regional, Low - High P, High T; ex. biotite and olivine)
• Blue-schist (subduction zones, High P, Low T; ex. glaucophane)
• Eclogite (High P, High T; ex. garnet and pyroxene)
What does large grained igneous rocks tell us about their cooling history?
- Intrusive/ Plutonic
- Formed deep within the earth
- Cooled slowly
What do fine grained igneous rocks tell us about their cooling history?
- Extrusive
- Formed near the surface of the earth
- Cooled quickly
What can you infer from the clast sizes within sedimentary rocks - referring to their depositional environment?
(For example, large clast sizes come from (high or low?) energy environments, such as (a lake or river?)).
Large clast sizes usually mean that they were deposited from a high energy environment, such as it takes more energy to move larger particles. An example of a high energy environment is a fast-moving river.
Small clast sizes usually mean that they were deposited from a low energy environment, such as it does not take much energy to move smaller particles. An example of a low energy environment would be a lake or flood plain.
What is a mineral?
1.) naturally occurring
2.) characteristic chemical composition
3.) regular crystalline structure
4.) inorganic (cannot be made of living things)
