These definitions will be part of your quiz over the introductory material for the course. They will likely be provided in the form of some matching questions; you might also be asked to define a few terms.

Note: As originally envisioned, this page would have contained dozens of internal hyperlinks in order to allow you to compare various terms. However, after spending hours typing up those improvements, I inadvertently overwrote them with an older version (gotta love the lack of version protection in Lotus products). As a result, you are on your own. If someone wants to volunteer to create the hyperlinks, feel free.

Bedding - layers of sedimentary rock separated by distinguishable planar surfaces known as bedding planes.

Calcareous sediment - Sediment mainly composed of calcium carbonate, although dolomite and other less common carbonate minerals may be present as well as siliciclastic sediments; more-or-less synonymous with carbonate sediment; calcareous sediment is typically biogenic, although some may be of chemical origin.

Carbonaceous rock - a rock consisting primarily of carbon, e.g. coal. The carbon comes from an organic source (e.g. plants or algae) is initially concentrated through organic decomposition, and becomes more concentrated as the amount of water and other volatiles decreases through diagenesis (e.g.compression) during burial.

Carbonate sediment - sedimentary grains composed of carbonate minerals, typically containing numerous biogenic components such as skeletal fragments and algae.

Chronostratigraphic unit - a body of rock deposited during a specified interval of geologic time; the upper and lower boundary ages of the unit have been determined either directly or indirectly by absolute dating techniques; each corresponds to a specific geochronologic unit and is placed in named divisions: eonothem, erathem, system, etc.; e.g. Jurassic System corresponds to the Jurassic Period.

Clastic sediment - particles composed of rock or mineral fragments and formed by erosion of bedrock primarily composed of silicate material. Grain size ranges from clay particles to boulders. Synonymous with "detrital".

Compositional maturity - A characteristic of siliclastic sediments or rock, which expresses compositional stability (i.e. resistance to chemical weathering) in terms of the abundance of quartz as compared to feldspar and rock fragments.

Conformable strata - sedimentary layers deposited in a more-or-less continuous sequence (i.e. there is no discernible time gap).

Correlation - determining that two or more geographically distant strata originated at the same time (chronocorrelation) or are the same rock unit (lithocorrelation).

Craton - ancient continental crust that may have been tectonically deformed but is now relatively stable.

*Cross-bedding - stratified layers within a bed that dip at an angle to the primary bedding orientation. These layers typically represent the preserved faces (foreset beds) of sand or gravel dunes. The term cross-bedding is usually reserved for cross-stratified layers thicker than 1 cm; if thinner, the term cross-laminations is used.

Depositional model - a graphic or descriptive representation for the sediment characteristics typical of a particular environment of deposition.

Detrital sediment - minerals and rocks derived from erosion of previously existing rocks or from weathered products of these rocks; synonymous with clastic sediment.

Diachronous strata - a rock unit that varies in age in different areas or cuts across biozones or time planes

Empirical classification - classification based on physical characteristics; c.f. genetic classification.

Epeirogeny - a series of crustal events (uplift and subsidence) that create local structures, such as domes, arches and basins. It does not result in serious deformation or faulting typical of orogenic events.

Epicontinental sea - a sea situated on the craton or along its margins, i.e. an inland sea. The term epeiric sea is synonymous. c.f. pericontinental sea

Eustasy - fluctuations in world-wide sea level due to changes in the quantity of sea water or the volume of the ocean basins; a uniform change in global sea level, which can be caused by global climate changes or tectonic activity; e.g. glaciation results in sea level fall.

Facies change - a vertical or horizontal change in the characteristics of sedimentary strata, which results from changes in the environment conditions in which they formed.

Facies - the lithologic characteristics or paleontologic makeup of a rock.

Fining upward sequence - A sequence of beds in which the average grain size gradually decreases upwards, typically as a result of increasing water depth. c.f. graded bedding

Fissility - the tendency of a rock to split apart parallel to bedding.

Framework grains - the sedimentary particle size that is the main constituent of a deposit. Clastic sedimentary rocks are usually named for their framework grains, e.g. sandstones consist primarily of sand-sized grains.

Genetic classification - subdivision of something based on specified genetic traits, i.e. traits relating to how the subject originated; c.f. empirical classification.

Geochronologic unit - intervals of geologic time measured in years and placed in named divisions such as eons, eras, and periods; serves as the basis for time-correlation and a reference system for recording events of geologic history. c.f. chronostratigraphic units.

Gradational contact - a transition between two rock bodies that is not abrupt, rather one unit gradually becomes another; typically this refers to a change in lithology between two beds or facies.

Graded bedding - a type of bedding shown by particles growing finer from bottom to top. As opposed to a fining upward sequence, graded bedding typically refers to a textural change within a single bed, typically as a result of waning current speed. c.f. fining upward sequence

Induration - the process by which sediment is compacted and cemented to form sedimentary rock, especially refers to increased hardening of rock. Also refers to the degree of sedimentary rock durability with respect to weathering and erosion.

Intracratonic basin - a sedimentary basin that resides upon the ancient, stable crust of a continent. A sea within such a basin would be termed an epicontinental sea.

Isochronous strata - strata that were deposited at the same time.

Isostasy - ideal balance attained by material of differing densities if gravity were the only force governing the height of the crustal areas relative to each other. For example, loading of the crust by sedimentation would cause subsidence, unloading of crust by erosion would cause uplift.

Lamination - the finest stratification or bedding in sedimentary rocks, known as laminae; typical of shale, siltstone, and sandstone.

Lithification - the processes through which loose sediment becomes rock, principally by compaction and cementation.

Lithofacies - a body of rock which is characterized by certain physical and chemical properties.

*Lithology - the physical characteristics of a rock including texture, composition, and color.

Lithostratigraphic unit - a relatively homogenous body of rock identified by its physical and chemical characteristics, and stratigraphical position, but not by its biological components nor by other indicators of age; the basic unit is the formation.

Matrix - smaller size sediment particles that are present between larger (i.e. framework) grains in clastic sedimentary rocks.

Orogeny - the process by which mountains are formed, including folding, faulting, volcanism, isostatic compensation, etc.

Pericontinental sea - a marine water body covering the margin of a continent, i.e. the continental shelves. c.f. epicontinental seas.

Permeability - the measure of a rock's ability to allow water to pass through it.

Porosity - the amount of void space in a rock; typically expressed as a percent of total rock volume.

Prograding shoreline - migration of the shore to seaward; typically resulting when more sediment is being supplied than space created for it, deposits will build upward and outward along shoreline. c.f. regression

Provenance - referring to the place of origin of a rock or clastic sediment.

Regression - A lowering of sea level. This may be either local (e.g. due to tectonic uplift) or global (e.g. due to glacial ice expansion). As a result, terrestrial environments typically migrate over formerly marine substrate. c.f. prograding shoreline

Roundness - the degree to which a sedimentary grain's edges and corners are rounded. This is related to the degree and duration of abrasion to which a sediment has been exposed, and is considered indicative of the distance or duration of sediment transport. c.f. sphericity

Sediment texture - the sorting, sphericity, and size of grains composing a sedimentary rock.

*Sedimentary basin - a depressed area of the crust into which sediment is or has been transported from the surrounding land surface.

Sedimentary platform - the ancient, flat-lying or gently dipping sedimentary rocks that compose the craton and lap onto the edges of the older, more deformed rocks of the continental shields.

Sedimentary structure - any of the features of sedimentary rocks produced by physical, chemical, or biological means, during or after sedimentation. Sedimentary structures often reflect the conditions under which the sediment was deposited.

Sorting - the mechanical segregation of particles during transport based on their size, shape, or density. This is related to the transport media (wind, water, or ice) and the distance and duration of transport.

*Sphericity - a measure of the deviation of a grain's outline from the shape of a perfect sphere. This is related to the degree and duration of abrasion to which a sediment has been exposed, and is considered indicative of the distance or duration of sediment transport. c.f. roundness

Terrigenous sediment - sediment eroded from subaerially exposed rock, which is later transported to and deposited in a marine environment. This refers primarily to sediment of siliciclastic composition.

Textural maturity - the degree of change in size and shape that sediment has undergone since being weathered from bedrock. It can be used to make inferences on the rock's erosional, transport, and depositional history.

*Transgression - A rise of sea level. This may be either local (e.g. due to crustal subsidence) or global (e.g. due to glacial meltwater). As a result, terrestrial environments are flooded and overlain by marine sediments.

Walther's Law - a principle developed by Johannes Walther that states that each facies in a conformable vertical sequence must have formed in a depositional environment adjacent to those facies directly above or below it in the sequence. Therefore, the vertical order of facies in a conformable sequence is indicative of the migration of sedimentary environments over time.

Student authors of these definitions are listed below in alphabetical order. After submission of the definition assignment, some were edited for content, others definitions were provided by your instructor. Hopefully, this all represents original prose, as opposed to something plagiarized from published sources. If you suspect the latter, please let me know: cdharris@mtsu.edu

Baxter, Jennifer; Bishop, Lougan; Bone, Michael; Boyte, Paul; Brown, William; Craycraft, Jessica; Cullom, Deidre; DeMarse, Jonathan; Ford, Lori; Glosson, Eva M.; Kennedy, Clay; Lowery, Greg; Popp, Daniel; Underwood, Shay.