Final Exam Prep Flashcards
Definiton of a mineral?
a mineral consists of an ordered array of atoms chemically bonded to form a particular crystalline structure
What is Igneous rock/ how is it formed?
usually magma, formed from partial melting of rock inside the earth
3 types of Igneous rocks?
- felsic (mature/ feldspar quartz)
- Intermediate (mixture of both felsic and mafic)
- Mafic/ ultramafic (oceanic/ magnesium)
What is a sedimentary rock?
formed from precipitation, sedimentation, and accumulation/ erosion of weathered rock material or soil.
contains evidence of past life/ past environments/ sedimentary transport
3 types of sedimentary rock?
- detrial (transported fragments)
- chemical (precipitate from solution)
- Organic (remains of organisms) ex: coal, fossils, limestone
What is a metamorphic rock?
changes in solid rock when a rock is subjected to temperatures or pressures very different from where they were formed. The parents rock can be of any type.
The 2 types of Metamorphism?
- Contact (rocks around an igneous body are cooked as magma invades the host. aka direct contact to the rock)
- Regional (more common) (pressure or movement from far away, creates mountains, develops foliated rocks)
Principle of Original Horizontality
Most sedimentary rocks are deposited in horizontal beds (there are exceptions, such as inclined sedimentation in alluvial fans, dunes, and deltas, but the overall bed is still more or less horizontal)
Principle of Superposition
If the rocks are still in their original depositional position (horizontal), then the oldest bed will be at the bottom and the beds will get progressively younger towards the top.
Principle of Cross-Cutting Relations
If one rock unit/type cuts across another, it must be younger than the rock it cuts. We also use cross-cutting relations for features that physically cut the rocks (like faults) or processes that have affected the rocks (like folds)
Principle of Inclusions
Pieces of one rock are sometimes enclosed (included in) another. This can be in sedimentary rocks (conglomerate, breccia) or in igneous rocks when an intrusion encloses a piece of host rock (xenoliths). The rock inside must then be older.
The 3 types of Unconformities?
- Angular Unconformity (where horizontal, parallel layers of sedimentary rock are deposited on top of tilted and folded eroded layers)
- Disconformity (separates parallel beds when time is missing due to erosion or non-deposition
- Nonconformity (an erosional surface that separates older igneous or metamorphic rocks from sedimentary rocks deposited on top)
The 3 types of Faults
- Normal Fault (the hanging wall moves down compared to the foot wall. These fault form in extensional environments, or parallel to the main stress direction)
- Reverse/thrust fault ( the hanging wall moves up, or over, compared to the foot wall.
- Strike-Slip Fault (has no component of vertical movement, and only accommodates movement in the horizontal sense. There are two types of strike-slip faults, sinistral (left-handed movement) and dextral (right-handed movement)
Thrust fault?
A thrust fault is a type of reverse fault in which the angle between the fault and the horizontal is low (ca. 10-40°). A thrust fault is still classified as a reverse fault. These faults form in compressional environments, or perpendicular to the main stress direction
The 2 types of Folds
- Antiform (Forms a sad face/ classify an antiform as an anticline if the units get older towards the inside. If we are unsure of relative ages, OR if they get younger towards the inside, we just call it an antiform fold)
- Synform (Forms a happy face/ classify a synform as a syncline if the units get younger towards the inside. If we are unsure of relative ages, OR if they get older towards the inside, we just call it a synform fold)
2 Types of Mass Wasting
- Rotational Slide/ Slump (Results from a failure of the rock or material itself. falls right down into ground)
- Translational Slide/ Rockslide (the slip surface occurs along a plane of weakness, commonly a bedding plane, joint, or fault. In this case, the rock itself is stronger than the force of friction (resistance) along this plane, and when the slope fails, the plane fails first)
LNAPL
Light Non-Aqueous Phase Liquid:
- lower density than water/ lighter (travels above)
- Travels with groundwater
- NOT water soluble
Ex: hydrocarbons (methane, propane), oils
DNAPL
Dense Non-Aqueous Phase Liquid - higher density that water/ heavier (travels under) - NOT water soluble - Travels along bedrock Ex: mercury, dry cleaning fluid
How Hydrocarbons are mined (oil and gas)
- source rock (where it originates)
- cap rock (to trap it in)
- reservoir (to hold and mine from)
What is a “hot spot”?
volcanic: an area in the mantle from which heat rises in the form of a thermal plume from deep within the Earth. Forms strings of islands (Hawaii)
Aphanitic
Fine-grained texture, fast cooling, tiny crystals
Phaneritic
Course-grained texture, slow cooling larger crystals
Pegmatitic
Very course-grained
Porphyritic
Mixture of fine and course grains
Pyroclastic
Fragments of grains
Glassy
No crystals, very fast cooling (obsidian)
3 Types of soils
- Pedalfer (humid, organic-rich)
- Pedocal (low clay, high calcium carbonate)
- Laterite (hot, wet, red colour due to iron and aluminum)
Tidal Flats
Areas affected by tidal currents
Estuaries
Inlet of the sea formed at the mouths of a stream
Diagenesis
All chemical, physical, and biological changes on sediments before metamorphism.
Lithification
Sediments transformed into solid sedimentary rock due to complication and cementation.
Three factors of Foliation
- Rotation of platy and/or elongated material grains into a new orientation.
- Changing the shape of equity-dimensional grains to elongate shapes aligned in the preferred orientation
- Re-crystallization of minerals to form new grains growing in direction of preferred orientation.
Advection
Contaminants “go with the flow”
Global Warming
increase in fossil fuel emissions cause an overall earth increase in temperature (0.8 degree increase since mid 20th century)
Climate Change
Ice melting earlier, glaciers shrinking, plant and animal ranges shifting, plants blooming earlier
