Geology Exam #2

Front 1

Anticline

Back 1

Type of deformation in which rocks are folded up into an arch (think of the top of A)

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Syncline

Back 2

Type of deformation in which rocks are folded down into a trough (think of the bottom of s)

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Basin

Back 3

Large low laying area, often below sea level that collects sediment

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Dome

Back 4

Anticlines that intersect each other

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Hinge or Axis

Back 5

Part of the deformation of an originally flat rock where it is folded

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Limb

Back 6

Flanks (sides) of the fold

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Pressure Release melting

Back 7

ff

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Volatiles

Back 8

Gasses form, in volcanoes, especially water and C02, increasing volume and pressure

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Extrusive Igneous Rocks

Back 9

Magma reaches earth's surface and cools quickly (volcanic)

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Intrusive Igneous Rocks

Back 10

When magma cools slowly in earth's surface (plutonic). Most have large, well-formed crystals.

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Felsic Igneous Rocks

Back 11

Rocks that are relatively rich in elements that form feldspar and quartz. Most common: granite

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Viscosity

Back 12

Magma's thickness or how easily it flows. Low viscosity=low silica

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Bowen's Reaction Series

Back 13

Explains why certain types of minerals tend to be found together, while others are almost never associated with one another.

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Granite

Back 14

Igneous rock with at least 20% quartz and up to 65% alkali feldspar by volume

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Basalt

Back 15

Extrusive (igneous) volcanic rock formed from the rapid cooling of basaltic lava exposed at or very near the surface of a planet or moon.

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Magma Chamber

Back 16

The chamber where the magma gathers

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Pluton

Back 17

Body of igneous rock that is crystalized from magma slowly cooling below the surface of the earth.

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Batholith

Back 18

Large emplacement of igneous intrusive rock that forms from cooled magma deep in the earth's crust. Almost always made mostly of felsic or intermediate rock types.

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Dike

Back 19

Sheet of rock that formed in a fracture in a pre-existing rock body. Intrude relatively vertical through a bedding plane.

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Sill

Back 20

A tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or even along the direction of foliation in metamorphic rock. Intrude horizontally along the bedding plane.

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Composite (strata) volcano

Back 21

Constructed from multiple eruptions, sometimes recurring over hundreds of thousands of years from layers of lava, debris, and tephra.

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Shield Volcano

Back 22

Built almost entirely from fluid, low-viscosity lava flows which travel farther than that of composite volcanos . Named for their large size and low profile, resembling a warrior's shield lying on the ground.

Front 23

Flood basalt

Back 23

Repeated eruptions and lava flows over a large area and extended time frame which results in a coating of a large stretch of land or ocean with basalt lava.

Front 24

Pyroclastics

Back 24

Ejected material that freezes in midair, or slides downslope, or flows in a wet slurry. Clastic rocks composed solely or primarily of volcanic materials.

Front 25

Crater

Back 25

Circular depression in the ground caused by volcanic activity. Typically a basin, circular in form within which occurs a vent from which magma erupts as gasses, lava, and ejecta.

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Caldera

Back 26

Formed by the collapse of land following a volcanic eruption. Sometimes confused with craters. Triggered by the emptying of the magma chamber beneath the volcano, usually as a result of a large volcanic eruption.

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Active Volcano

Back 27

One that has erupted since the last ice age

Front 28

Dormant Volcano

Back 28

One that hasn't erupted in the past 10,000 years

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Extinct Volcano

Back 29

One that no one expects to erupt ever again

Front 30

Explosive erruptions

Back 30

-Krakatau 1883: four large explosions completely destroyed the island

-79 AD: Mount Vesuvius, pyroclastic flows completely destroyed Pompeii

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Yellowstone Caldera

Back 31

Last errupted 640 KA: created 100 km caldera. Deposited ash over much of US. 1,000 times more powerful than Mt St. Helens. Continues to fuel geysers.

Front 32

Volcanoes and climate

Back 32

-Ash and aerosols high in atmosphere block sunlight, causes atmospheric cooling

-Ex: 1815 Mt Tambora ejected pyroclastic debris into atmosphere leading to 1816 "Year without a summer" in North America and Europe

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Metamorphism

Back 33

Change of minerals or geologic texture in pre-existing rocks (protoliths), without the protolith melting into liquid magma. The change occurs primarily due to heat, pressure, and the introduction of chemically active fluids.

Front 34

Contact metamorphism

Back 34

Occurs typically around intrusive igneous rocks as a result of the temperature increase caused by the intrusion of magma into cooler country rock. Rocks formed by it may not present signs of strong deformation, may be coarse grained.

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Regional metamorphism

Back 35

Covers large area of continental crust typically associated with mountain ranges, particularly those associated with convergent tectonic plates or the roots of perviously eroded mountains.

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Joints

Back 36

Break or fracture of natural origin in the continuity of either a layer or body of rock that lacks any visible or measurable movement parallel to the surface (plane) of the fracture.

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Fault

Back 37

Planar fracture or discontinuity in a volume of rock, across which there is has been significant displacement as a result of rock mass movement. Large faults result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as subduction zones or transform faults.

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Fold

Back 38

When one or a stack of originally flat and planar surfaces, such as sedimentary strata, are bent or curved as a result of permanent deformation. Due to slumping of sedimentary material before it has lithified. Vary from microscopic crinkles to mountain-sized folds.

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Brittle

Back 39

type of deformation in which the rock breaks

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Ductile

Back 40

When rock bends or flows like clay

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Strike

Back 41

Direction of horizontal line on inclined rock surface where it intersects a plane.

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Dip

Back 42

Direction in which the steepest angle is formed between the plane of the rock bed and the horizontal surface (slope)

Front 43

Dip-slip Fault

Back 43

When the two pieces separating in the fault move up and down.

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Strike-Slip Fault

Back 44

When the two pieces separating in the fault move side to side

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Hanging wall

Back 45

Block positioned over the fault

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Foot wall

Back 46

Block positioned under the fault

Front 47

Normal Fault

Back 47

Hanging wall moves downward relative to foot wall

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Thrust (reverse) fault

Back 48

Hanging wall moves up relative to footwall

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Sedimentary Rock

Back 49

Rock formed by deposition of material at the earth's surface and within bodies of water. Caused by weathering (chemical and physical breakdown), erosion (removal of sediment grains from rock), transportation (dispersal by water, wind, and ice), deposition (settling out of transporting fluid), and lithification (transformation into solid rock).

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Sediment transport

Back 50

Movement of solid particles due to gravity and movement of water, wind, and ice.

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Lithification

Back 51

Process by which sediments compact under pressure, expel connate fluids, and gradually become solid rock.

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Clastic Rocks

Back 52

Composed of fragments (or clasts) of preexisting minerals and rocks. Classified based on texture and composition. Last (grain) size, last composition, angularity and sphericity, sorting, and character of cement.

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Biochemical Rocks

Back 53

Form from gradual accumulation of biological material such as shells or dead plant material.

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Organic Rocks

Back 54

Sedimentary rock composed principally of the remains of plants and animals.

Front 55

Chemical Precipitation Rocks

Back 55

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Front 56

Sorting

Back 56

Distribution of grain size of sediments. Poorly sorted=different grain sizes together, well sorted=same grain sizes together

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Cements

Back 57

Chemically precipitated substance that binds clastic rocks

Front 58

Carbonic acid

Back 58

CO2 combined with water in soil, which intensifies corrosive ability of water percolating into the soil and moving through fractured rock.

Front 59

Sinkholes

Back 59

Circular depressions that form when water erodes easily dissolved or soluble rock located beneath the ground surface.

Front 60

Sandstone

Back 60

Clastic sedimentary rock composed of sand-sized minerals or rock grains.

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Shale

Back 61

Fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite.

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Mudstone

Back 62

Fine grained sedimentary rock whose original constituents were clays or muds.

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Limestone

Back 63

Sedimentary rock composed mostly of the minerals calcite and aragonite, which are different forms of calcium carbonate. Most limestone composed of skeletal fragments of marine organisms such as coral, forams, and molluscs.

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Ores

Back 64

-Rock with concentration of metal-rich minerals

-Present in enough abundance to be mineable

-Metal must be readily extracted from the mineral

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Magmatic Deposits

Back 65

Deposits of minerals formed deep in the earth's crust during the solidification and crystallization of basic magma containing high concentrations of valuable minerals.

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Hydrothermal Deposits

Back 66

Concentration of metallic minerals formed by the precipitation of solids from hot mineral-laden water.

Front 67

Secondary enrichment

Back 67

Groundwater leaches and oxidizes primary sulfide ores.

Front 68

Chemical weathering deposits

Back 68

Intense weathering leaches most soluble elements from the soil.

Front 69

Sedimentary Deposits

Back 69

Mineral deposits formed during the accumulation of sediment on the bottom of rivers and other bodies of water.

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Oil Window

Back 70

During the mature stage at depths of 760-4880 meters at temperatures between 65 and 150 degrees c.

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Source Rock

Back 71

Rocks from which hydrocarbons have been generated or are capable of being generated.