Term
|
Definition
| A fold with an arch-like shape in which the limbs dip away from the hinge |
|
|
Term
|
Definition
| the angle of the steepest slope that a pile of uncemented material can attain without collapsing from the pull of gravity |
|
|
Term
|
Definition
| a turbulent cloud of debris mixed with air that rushes down a steep hill slope at high velocity; the debris can be rock/ and or snow |
|
|
Term
|
Definition
| in the context of folds, this is the imaginary plane that contains the hinge lines of successive layers in the fold; it is the surface that divides a fold into its two separate limbs |
|
|
Term
|
Definition
| a fold or depression shaped like a right side up bowl |
|
|
Term
|
Definition
| the cracking and fracturing of a material subjected to stress |
|
|
Term
|
Definition
| the remarkable diversification of life, indicated by the fossil record, that occurred at the beginning of the cambrian period |
|
|
Term
|
Definition
| the boundary surface between two rock bodies |
|
|
Term
|
Definition
| the process of defining the age relations between the strata at one locality and the strata at another |
|
|
Term
|
Definition
| the gradual downslope movement of regolith |
|
|
Term
|
Definition
| a means of determining the relative age of rock by looking at which rock or structure cuts another, the feature that has been cut is older |
|
|
Term
|
Definition
| a push or squeezing felt by a body |
|
|
Term
|
Definition
| a long lived block of durable continental crust commonly found in the stable interior of a continent |
|
|
Term
|
Definition
| the decay product of radioactive decay |
|
|
Term
|
Definition
| a sudden collapse of disaggregated material on a steep slope |
|
|
Term
|
Definition
| a downslope movement of mud mixed with larger rock fragments |
|
|
Term
|
Definition
| a sudden downslope movement of material consisting only of regolith |
|
|
Term
|
Definition
| a change in the shape, position, or orientation of a material, by bending, breaking, or flowing |
|
|
Term
|
Definition
| the angle at which a layer tilts, relative to horizontal; the angle is measured in an imaginary vertical plane that trends perpendicular to the strike |
|
|
Term
|
Definition
| the amount of movement or slip across a fault plane |
|
|
Term
|
Definition
| folded or arched layers with the shape of an overturned bowl |
|
|
Term
|
Definition
| the bending and flowing of a material subjected to stress |
|
|
Term
|
Definition
| the largest subdivision of geologic time |
|
|
Term
|
Definition
| an interval of geologic time representing the largest subdivision of a period |
|
|
Term
|
Definition
| an interval of geologic time representing the largest subdivison of the phanerozoic eon. |
|
|
Term
|
Definition
| the detachment or sliding horizon on which downslope movement of rock or debris occurs |
|
|
Term
|
Definition
| a fracture on which one body of rock slides past another |
|
|
Term
|
Definition
| a small step on the ground surface where one side of a fault has moved vertically with respect to the other |
|
|
Term
|
Definition
| a bend or wrinkle of rock layers or foliation; folds form as a consequence of ductile deformation |
|
|
Term
|
Definition
| layering formed as a consequence of the alignment of mineral grains, or of compositional banding in a metamorphic rock |
|
|
Term
|
Definition
| the principle that the assemblage of fossil species in a given sequence of sedimentary strata differs from that found in older sequences or in younger sequences; a given species appears at a certain level and then disappears at a higher level |
|
|
Term
| global positioning system |
|
Definition
| a satellite system people can use to measure rates of movement of the earth's crust relative to one another, or simply to locate their position on the earth's surface |
|
|
Term
|
Definition
| a composite stratirgraphic chart that represents the entirety of the Earth's history |
|
|
Term
|
Definition
| a map showing the distribution of rock units and structures across a region |
|
|
Term
|
Definition
| the span of time since the formation of the earth |
|
|
Term
|
Definition
| a scale that describes the intervals of geologic time |
|
|
Term
|
Definition
| the time it takes for half of a group of a radioactive element's isotopes to decay |
|
|
Term
|
Definition
| the distinct step along the upslope edge of a slump where the regolith detached |
|
|
Term
|
Definition
| the portion of a fold where curvature is greatest |
|
|
Term
|
Definition
| different versions of a given element that have the same atomic number but different atomic weights |
|
|
Term
|
Definition
| the science of dating geologic events in years by measuring the ratio of parent radioactive atoms to daughter product atoms |
|
|
Term
|
Definition
| the condition that exists when the buoyancy force pushing lithosphere up equals the gravitational force pulling lithosphere down. |
|
|
Term
|
Definition
| naturally formed cracks in rocks |
|
|
Term
|
Definition
| a thick slurry formed when volcanic ash and debris mix with water, either in rivers or from rain or melting snow and ice on the flank of a volcano |
|
|
Term
|
Definition
| a sudden movement of rock and debris down a nonvertical slope |
|
|
Term
|
Definition
| the transformation of seemingly solid sediment into a liquid like slurry, in response to ground shaking |
|
|
Term
|
Definition
| the side of a fold, showing less curvature than at the hinge |
|
|
Term
|
Definition
| the gravitationally caused downslope transport of rock, regolith, snow, or ice |
|
|
Term
|
Definition
| a downslope movement of mud at slow to moderate speed |
|
|
Term
|
Definition
| a fold in the land surface whose shape resembles that of a carpet draped over a stair step |
|
|
Term
|
Definition
| a situation or setting caused by natural processes that can result in damage to society |
|
|
Term
|
Definition
| the age of a rock or structure as specified in years; referred to as "absolute age" in older literature |
|
|
Term
|
Definition
| a fualt in which the hanging wall block moves down the slope of the fault |
|
|
Term
|
Definition
| the principle that sediments are deposited in nearly horizontal layers |
|
|
Term
|
Definition
| the process in which mountains begin to collapse under their own weight and spread out laterally |
|
|
Term
|
Definition
| a linear range of mountains |
|
|
Term
|
Definition
| a radioactive isotope that undergoes decay |
|
|
Term
|
Definition
| an interval of geologic time representing a subdivision of a geologic era |
|
|
Term
|
Definition
| the interval of geologic time between earth's formation about 4.57 Ga and the beginning of the Phanerozoic Eon 542 Ma |
|
|
Term
|
Definition
| force per unit area, or the "push" acting on a material in cases where the push is the same in all directions |
|
|
Term
|
Definition
| the process by which a radioactive atom undergoes fission or releases particles, thereby transforming into a new element |
|
|
Term
|
Definition
| the age of one geologic feature with respect to another |
|
|
Term
|
Definition
| a steeply dipping fault on which the hanging-wall block slides up |
|
|
Term
|
Definition
| a sudden collapse of bedrock down a steep slope |
|
|
Term
|
Definition
| a sudden downslope movement of rock |
|
|
Term
|
Definition
| a stress that moves one part of a material sideways past another part |
|
|
Term
|
Definition
| an older, interior region of a continent |
|
|
Term
|
Definition
| downslope movement in which a mass of regolith detaches from its substrate along a spoon-shaped sliding surface and slips downward semicoherently |
|
|
Term
|
Definition
| the type of creep characteristic of tundra regions; during the summer, the uppermost layer of permafrost melts, and the soggy, weak layer of ground then flows slowly downslope in overlapping sheet. |
|
|
Term
|
Definition
| the change in shape of an object in response to deformation |
|
|
Term
|
Definition
| the push, pull, or shear that a material feels when subjected to a force; formally, the force applied per unit area over which the force acts. |
|
|
Term
|
Definition
| the compass trend of an imaginary horizontal line on a plane |
|
|
Term
|
Definition
| a fault in which one block slides horizontally past another, so there is no relative vertical motion |
|
|
Term
|
Definition
| a cross-section diagram of a sequence of strata summarizing information about the sequence |
|
|
Term
|
Definition
| a recognizable layer of a specific sedimentary rock type or set of rock types, deposited during a certain time interval, that can be traced over a broad region |
|
|
Term
|
Definition
| the principle that younger layers of sediment are deposited on older layers of sediment; thus, in a sequence of strata, the oldest layer is at the base |
|
|
Term
|
Definition
| a trough-shaped fold whose limbs dip toward the hinge |
|
|
Term
|
Definition
| a wedge shaped pile of rock fragments that accumulates at the base of a cliff |
|
|
Term
|
Definition
| a stress that pulls on a material and could lead to stretching |
|
|
Term
|
Definition
| a gently dipping reverse fault; the hanging wall lock moves up the slope of the fault |
|
|
Term
|
Definition
| excavation at the base of a slope that results in the formation of an overhang |
|
|
Term
|
Definition
| a boundary between two different rock sequences representing an interval of time during which new strata were not deposited |
|
|
Term
|
Definition
the principle that the same physical processes observed today are responsible for the formation of ancient geologic features;
"the present is the key to the past" |
|
|
Term
|
Definition
| the upward vertical movement of the ground surface as occurs during mountain building |
|
|
Term
|
Definition
| a seam of minerals that forms when dissolved ions carried by water solutions precipitate in cracks |
|
|
