Term
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Definition
| flat surface separating rock layers. This flat surface is created by changes in sediment types. These bedding planes mark the beginning of a new episode of deposition and a new environment. |
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Definition
| sediment deposited at an inclined angle. Examples of this are sand dunes and river deltas |
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Term
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Definition
| sedimentary rocks are made up of different particles. Particle size in a single sedimentary layer gradually change from being coarse at the bottom to being fine at the top. |
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Definition
| Evidence that small waves developed at the surface of a sediment by moving water or air. The direction of flowing ancient wind or air is shown by these. The ridges form at a right angle to the direction of flow. |
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Definition
| Remains or trace of prehistoric life. This is a preservation of hard parts (bones, teeth) by rapid burial. These can be environmental and time indicators as well. If the fossil has thick, wide shells then it means it lived in a shallow area with high energy. If the fossil has a thin shell it means it lived in the deep ocean in a low energy environment. |
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Definition
| polygon-shaped cracks created by drying of clay in wet environments. This is also a sign of rich sediment. |
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Term
| Detrital Rock (other name) |
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Definition
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Term
| Major minerals in clastic rocks |
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Definition
| clay minerals, quartz, feldspar and mica |
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Term
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Definition
| this changes in size depending on the energy of the environment it is found in. The higher the energy the bigger the particle size. |
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Definition
*fine grained
*accounts for +50% of sedimentary rocks
*deposited in low energy areas such as deep ocean basin |
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Term
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Definition
1. Quartz Sandstone
2. Arkose Sandstone
3. Graywacke |
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Term
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Definition
| sandstone made with quartz |
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Term
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Definition
1. Made of quartz, sandstone and mica
2. weathered from granite
3. deposited close to the source in a dry environment |
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Term
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Definition
1. Sandstone made of quartz, feldspar, rock fragment and clay
2. poorly sorted with angular grains |
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Term
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Definition
1. sedimentary rock made of large rounded gravels
2. poorly sorted large gravels, sand and mud
3. deposited at the base of a steep slope from turbulent current |
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Term
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Definition
1. large angular gravels mixing with sand and mud
2. poorly sorted |
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Term
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Definition
| relatively uniform particle size distribution; shows transportation over long distance and time |
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Definition
| markedly different particle size; shows transportation over a short distance and time |
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Definition
| show a great deal of abrasion during transport |
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Term
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Definition
| show that the rock was transported over a short period of time |
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Definition
| formed from the evaporation of salt water |
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Term
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Definition
1. Rock Gypsum
2. Rock Salt |
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Term
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Definition
| evaporate, chemical sedimentary rock that is formed after 75% of seawater has evaporated |
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Term
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Definition
| evaporate, chemical sedimentary rock that is formed after 90% of seawater has evaporated |
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Term
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Definition
1. calcite precipitated by organic or inorganic processes
2. most abundant chemical sedimentary rock |
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Term
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Definition
| marine shell fragments cemented by calcite |
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Term
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Definition
| a soft, porous rock made of microscopic marine organisms. An example of this is the white cliff of dover in england |
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Term
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Definition
| small spherical nuclei such as sand grain and shell fragment surrounded by concentric layers of calcite |
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Term
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Definition
| CaMgCO3 minerals formed in seawater |
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Term
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Definition
| great quantity of rocks are subjected to intensive T and P. Large scale deformation in subduction zone |
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Term
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Definition
| rocks are altered with contact with non-molten magma |
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Term
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Definition
| comets and astroids impact |
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Term
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Definition
| formed from shale due to sheer stress and split along layers of mica into slabs. Examples include slate and phyllite |
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Term
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Definition
| formed from slate under a high degree of metamorphism. It is not split as easily as slate into slabs because of recrystalization. An example of this is schist. |
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Term
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Definition
| formed from schist under highest degree of metamorphism. It has a banded appearance with a segregation between dark and light minerals. This will not split into slabs like slate. |
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Term
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Definition
| parallel alignment of platy minerals (micas). Forms mainly as a consequence of pressure. |
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Term
| order of metamorphism (low to high) |
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Definition
| 1. slate 2. phyllite 3. schist 4. gneiss 5. migmatite |
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Term
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Definition
| metamorphic rocks that consist of one mineral with no preferred orientation (equi-dimensional); a mosiac (interlocking) of equi-dimensional minerals created by recrystalization. Examples of this are marble and quartzite. |
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Term
| marble (metamorphic makeup) |
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Definition
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Term
| quartzite (metamorphic makeup) |
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Definition
| metamorphic quartz sandstone |
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Term
| index minerals for intensity of metamorphism (least to greatest) |
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Definition
1. chlorite
2. biotite
3. garnet
4. staurolite
5. kyanite
6. sillimanite |
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Term
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Definition
| *shallow subduction zone near trench *Blueschist facies (amphibole glauconphane) *example: coast range in California |
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Term
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Definition
*contact metamorphism due to igneous intrusion in the continental crust
*examples: Sierra Nevada Batholith, hornfels |
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Term
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Definition
*deep subduction zone
*amphibole-granulite facies
*example: Alps in Northern Italy |
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Term
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Definition
| direction of a rock layer intersecting with a horizontal surface |
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Term
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Definition
| amount of tilting, measured at a right angle to the strike |
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Term
| compressive rock deformity |
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Definition
| pushed together; lead to reverse faults |
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Term
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Definition
| rocks pull away, lead to normal faults |
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Term
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Definition
| rocks slide past each other along a plane in opposite directions; lead to strike-slip faults |
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Term
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Definition
| undergoes little changes before it breaks suddenly. this dominates in shallow crust. an example is fault breccias |
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Term
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Definition
| undergoes smooth and continuous "plastic" deformation (ie clay); dominate deep crust and exhibit "flowing" or "rotation" deformation under high T and P; and example is mylonites |
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Term
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Definition
| parallel cracks without appreciable movements (displacement); formed tectonically or non-tectonically (by contraction of lava or erosion-expansion) |
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Term
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Definition
| a fracture with relative movement of rocks on sides of it; formed tectonically |
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Term
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Definition
| tensional stress, hanging wall moves down |
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Term
| (reverse or thrust) dip slip fault |
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Definition
| compressional stress, hanging wall moves up |
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Term
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Definition
| shear stress, lateral movement along strike |
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Term
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Definition
| involves movements in both strike and dip directions |
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Term
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Definition
| places geological events in sequential order based on their positions on geologic records. This does not tell how long ago something happened (exact time) but does tell the sequence of different events. |
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Term
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Definition
| use radioactive dating methods; this method can pinpoint the time when an event actually happened |
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Term
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Definition
| sedimentary layers or lava flow is older than the one above and younger than the one below |
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Term
| principle of original horizontality |
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Definition
| sedimentary layers are generally deposited in a nearly horizontal position (influenced by gravity) |
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Term
| principle of lateral continuity |
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Definition
| sediments extended laterally in all directions until they "pinch out" along the edge of a sedimentary basin |
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Term
| principle of cross-cutting relationship |
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Definition
| igneous intrusion or fault must be younger than the rocks it intrudes or cuts |
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Term
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Definition
| inclusions (fragments of rock contained within host layer) are older than the rock layer that contains it |
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Term
| principle of faunal succession |
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Definition
| layers with the same fossils are the same age |
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Term
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Definition
| tilted or folded sedimentary rocks overlain by younger, flat-lying rocks; older rocks dip more |
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Term
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Definition
| surface of erosion or non-disposition between younger and older rocks that are parallel |
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Term
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Definition
| erosion surface separating metamorphic or igneous rocks and younger sedimentary rocks |
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Term
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Definition
| the basis of correlation across continents |
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Term
| the two different correlation methods |
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Definition
1. match positions or rocks in different sequences
2. match lithologic identity |
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Term
| limitations of using lithology |
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Definition
| correlation based on rock type (lithology) only works for a short distance, correlation across continents is based on "index fossils" |
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Term
| radioactivity of isotopes |
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Definition
| the forces binding protons and neutrons are not strong, so the nuclei decay and break apart spontaneously |
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Term
| 3 types of radioactive decay |
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Definition
1. alpha
2. beta
3. E-capture |
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Term
| what are the two things that radioactive dating requires |
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Definition
1. Half-life
2. parent/daughter isotope ratios |
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Term
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Definition
| time required for 50% of unstable parent isotopes to decay to more stable daughter isotopes (C14 is about 5730 years) |
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Term
| what is parent/daughter isotope measured by? |
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Definition
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Term
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Definition
| if half-life of a parent isotope is 2 million years (m.y.), the sample with the p/d ratio of 1/1 has an age of 2 m.y.; sample with p/d ratio of 1/3 has an age of 4 m.y.; sample with p/d ratio of 1/7 has an age of 6 m.y. |
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