Geologic Structures Flashcards
structural geology
study of how geologic units are are arranged when first formed and how they are deformed after
Geologic units
bodies of rock or sediment
geologic map
shows the distribution of rocks at earths surface
formations
mappable units of rock
beds
individual layers of rock or sediment
contacts
boundaries between geologic units
geologic cross section
drawing of a vertical slice through earth, with the material in front of it removed
shows topography and arrangement of formations
block diagram
combination of a geologic map and cross section
strike
the direction of a line formed by the intersection of the surface of a inclined (tilted) rock layer and a horizontal plane
dip
maximum angle of inclination of the rock layer, always measured perpendicular to the line of the strike and the direction that the rock layer tilts down to the ground
attitude
orientation of a rock unit or surface
disconformity
unconformity between relatively parallel strata
angular unconformity
unconformity between nonparallel strata
nonconformity
unconformity between sedimentary rock/ sediment and non sedimentary rock (igneous/metamorphic)
where do unconformities usually occur
surface where erosion has occurred
