Term
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Definition
| The process by which rocks are chemically altered or physically brokedn down into fragments at or near the Earth's surface |
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Definition
| Break down of rocks into progressively smaller grains called detritus |
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Definition
| mechanical weathering that occurs due to presure release. Sheet joints form as the pressure is released during outward expansion of the rock and form exfoliation domes |
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| Role of joints in weathering |
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Definition
Increase surface area
allow water to endter the rock
promotes chemical weather |
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Definition
| joints intersect bedding planes and eventually transform solid rock into rubble called talus |
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Term
| thermal expansion and contration |
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Definition
| volume of rock changes as it heats and cools |
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Term
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Definition
| rock expands more on its outside than inside. Causes rocks to break apart |
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Term
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Definition
Decomposition of rock materials by reaction with chemical reagents
oxidation
Dissolution
hydrolysis |
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Term
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Definition
chemical reaction where an elemnt loses electrons
These reactions produce sulfuric acid which forms the basis of acid rain and is the main component of acid mine drainage |
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Term
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Definition
to cause to pass into solution.
-easiest type of chemical decomposition
-most mienrals aren't water soluble
-some minearls are especially soluble, the most important of which are calcite and halite. |
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Term
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Definition
breaking down minearls by the addition of water
-mostly affects silicate minerals
-water combines with CO2 to form carbonic acid |
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Term
| Factors that influence weathering |
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Definition
-Mineral stability- metastable minerals are more easily weathered
-surface area- more surface area=more rapid weathering
organisms- organisms may either cause mechanical weathering (root wedging) or produce natural acids taht create chemical weathering |
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Term
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Definition
Are from mechanical and chemical breakdown of preexisting rocks are by direct precipitation from aqeous solutions
compntents:
1.fragments
2. chemical precipitates (salt or gypsum)
3. materials formed by biochemical processes |
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Term
| Why are sedimentary rocks important |
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Definition
preserve recordds
90% of mineral products use come from sedimentary rocks (coal, oil, sand, etc)
Act as reservoirs for groundwater |
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Term
| Two broad types of sedimentary rocks |
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Definition
1. clastic or detrital- from pre-existing rocks by weathering
2. chemical and biochemical- from precipitation from aqueous solutions and/or by biochemical means |
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Term
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Definition
The conversion of sediments into rock
1. compaction and dewatering: As the weight of overlying materials increases, sediment grains are packed more tightly together, squesszing out water.
2. Lithification: Once the sediments have been tightly packed, water taht is rich in mineral components will deposit mineral cements in the remaining pore spaces |
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Term
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Definition
| drawing a diagram showing the vertical and sometimes horizontal relationships among and between strata in a given region |
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Term
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Definition
| stratigraphy is the term given to the study of the characteristics and attributes of rocks. Must be at least 100 m thick. |
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Definition
| strata are divided up into even smaller layers. Separate, distinct layers based on certain criteria |
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Term
| Similar rocks are grouped together as |
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Definition
formation-
member- a distinctive smaller unit within a formation
group- a series of formations that typically are related by common lithologic attributes |
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Term
| Sedimentary rocks and geologic time |
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Definition
System: corresponds to a geologic period
series: a subdivision of a system which corresponds to a geologic epoch
stage: a subdivision of series, a way to refine specific times within a geologic epoch |
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Term
| Clastic Sedimentary Rocks |
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Definition
Making a clastic sedimentary rock involves 4 steps
1. Weathering
2. Erosion/mass wasting/transportation
3. deposition
4. Diagenesis/lithification |
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Term
| classification of sedimentary rocks is based on |
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Definition
1. grain size
2. shape
3. mineroalogy |
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Definition
| of sediment is how far it has been transported from its source. |
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Term
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Definition
| refers to the range in sizes of the sediment |
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Term
| non detrital sedimentary rocks |
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Definition
| include the chemical and biochemical sedimentary rocks |
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Term
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Definition
occur in a restricted basin with episodic influx of water.
-Water is evaporated faster than it is supplied and limestone, gypsum, and rock salt precipitate out |
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Term
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Definition
cross beds
graded beds
ripple marks
mud cracks
fossils |
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Term
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Definition
downslope transfer of material by graviety
factors
1. saturation of material with water
2.earthquakes
3. oversteeoening of slopes
4. freeze thaw cycles |
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Term
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Definition
| regolith detaches from the substrate along a glad horizone and moves downsope |
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Term
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Definition
mudflow: material is small in size
debris: material contains cobble size and larger rock fragments |
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Term
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Definition
| When rocks are weathered and turn into sediments any type of unconsolidated debris produced is called_______. |
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Term
| Regolith behaves in three ways |
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Definition
1. It can breakdown further and evolve "in situ" and become soil
2. mass wasting
3. can turn back into sedimentary rock |
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Term
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Definition
| part of the regolith that has evolved and cna support and sustain plant life |
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Term
| how soil forms and what it is made of |
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Definition
1. the action of water
2. biological interaction
air
mineral matter
water
organic matter |
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