Name, Term, or Concept | Description/Definition |
catastrophism * | the view that most of earth's geological features are the result of large-scale catastrophes such as floods, volcanic eruptions, etc. |
uniformitarianism * | the view that most of earth's geological features are the result of slow, gradual processes that have been at work for millions or even billions of years |
humus * | the decayed remains of once-living creatures |
sedimentary rock | rock that is formed from sediments which are laid down by water or some other agent and fuse together due to heat, pressure, and various chemical reactions |
sediments | sand, silt, and other components of soil |
igneous rock | rock that forms from molten rock (magma, lava from volcanoes) |
metamorphic rock | rock that has undergone extreme change due to lots of heat and pressure |
minerals * | inorganic crystalline substances found naturally in the earth |
inorganic | did not come from a living being |
crystalline | having a very sharp, geometric shape |
strata | layers |
lamination | a single layer of rock that is less than 1 centimeter (0.39 inches) thick |
laminae | several lamination layers formed right next to each other |
weathering * | the process by which rocks are broken down by the forces of nature |
erosion * | the process by which sediments and rock fragments are carried away by wind or rain |
groundwater | water that flows underground |
cavern | open space underground where groundwater has eroded the rock |
stalactite | an icicle-like structure hanging down from the ceiling of a cavern formed by groundwater dripping and leaving sediment on the ceiling |
stalagmite | a structure rising from the ground of a cavern formed by groundwater dripping and leaving sediment on the ground where it dripped |
column | a structure formed in a cavern when a stalactite and a stalagmite meet and form a single structure |
unconformity * | a surface of erosion that separates one layer of rock from another |
angular unconformity | an unconformity where the rocks below are tilted relative to the rocks above |
nonconformity | separation between stratified layers and unstratified layers |
stratified | arranged in layers |
disconformities | unconformities where there are parallel, stratified rock layers above and below the unconformity, but a clear surface of erosion between them |
paraconformities | unconformities where geologists believe there is an unconformity but cannot identify it |
intrusion | "veins" of igneous rock shooting right through several layers of sedimentary rock, formed when magma from underneath the sedimentary rock gets injected in the cracks of the sedimentary rock |
sills | the "veins" of igneous rock that run in the same direction of the strata of the sedimentary rock |
dikes | the "veins" of igneous rock that run perpendicular to the strata of the sedimentary rock |