|
stratigraphy
|
The science of the description, correlation, and classification of strata in sedimentary rocks, including the interpretation of the depositional environments of those strata.
|
|
|
system (stratigraphy)
|
A stratigraphic unit larger than a series, consisting of all the rocks deposited in one period of an era.
|
|
|
Uniformitarianism, Principle of
|
The concept that the processes that have shaped the Earth through geologic time are the same as those observable today.
|
|
|
actualism
|
The interpretation of ancient rocks by applying the results of analyses of modern-day geologic processes in accordance with the principle of uniformitarianism.
|
|
|
Catastrophism
|
The doctrine that sudden violent and widespread events caused by supernatural forces formed most of the rocks that are visible at the earth's surface.
|
|
|
superposition, Principle of
|
The principle stated by Steno that, except in extremely deformed strata, a bed that overlies another bed is always the younger.
|
|
|
components principle
|
The principle stating that a body of rock is younger than any other body of rock from which any of its components are derived.
|
|
|
Original Horizontality, Principle of
|
The proposition of Steno, that all sedimentary bedding is horizontal at the time of deposition.
|
|
|
stratigraphic sequence
|
A set of bed deposited that reflects the geologic history of a region.
|
|
|
biostratigraphy
|
Relative (not absolute, i.e. number of years) age dating and time correlation of stratified rocks (mostly sedimentary plus some volcanics) by means of fossil contained in those rocks based on our knowledge of their time sequence locally regionally and globally -- all of this ultimately being a function of evolutionary change.
|
|
|
biostratigraphy
|
The study and classification of rocks and their history based on their fossil content.
|
|
|
biostratigraphic unlt
|
A body of rock uch as a zone defined on the basis of its fossil content and having approximately time-parallel upper and lower boundaries.
|
|
|
facies
|
The set of all characteristics of a sedimetary rock that indicates its particular environment of deposition and which distinguish it from other facies in the same rock.
|
|
|
conformable
|
Rock layer that were deposited in sequence without episodes of erosion between deposition of layers. .
|
|
|
unconformity
|
"The contact between older rocks and younger sedimentary rocks in which at least some erosion has removed some of the older rocks before deposition of the younger. An angular unconformity shows that the older rocks have been deformed and eroded before the younger sedimentary rocks were deposited; there is an angle between the bed of the older and the younger."
|
|
|
nonconformity
|
An type of unconformity in which young sedimentary rocks lie on top of older metamorphic or intrusive igneous rocks.
|
|
|
angular unconformity
|
An unconformity separating horizontal strata above from older strata that had been tilted and eroded.
|
|
|
transgression
|
A rise in sea level relative to the land which causes areas to be submerged and marine deposition to begin in that region.
|
|
|
regression
|
A drop in sea level that causes an area of the Earth to be uncovered by sea water, ending marine deposition.
|
|
