What is carbonate ramp?
Carbonate ramps are carbonate platforms which have a very low gradient depositional slope (commonly less than 0.1°) from a shallow-water shoreline or lagoon to a basin floor (Burchette & Wright 1992). A large proportion of carbonate successions in the geological record were deposited in ramp-like settings.
How do you distinguish between ramp and shelf environments?
Ramps differ from rimmed shelves in the absence of continuous shelf-marginal reef trends, the location of high-energy deposits near the shoreline and not at the shelf edge, and the lack of shallow-water derived clasts in deep-water parts of the ramp.
What are carbonate slopes?
Commonly the carbonate slope lies above the lower limit of oxygenated water and so is able to support aerobic life forms. carbonate slopes can range in morphology from gentle gradients to steep cliffs. These differences in gradient are influenced by the sediment budget.
What is a rimmed shelf?
A rimmed carbonate shelf is a flat-topped platform that has a rim of reefs or carbonate sand shoals along the seaward margin. The reef or shoal forms a barrier that absorbs most of the wave energy from the open ocean.
How are carbonate platforms formed?
A carbonate platform is a sedimentary body which possesses topographic relief, and is composed of autochthonic calcareous deposits. Platform growth is mediated by sessile organisms whose skeletons build up the reef or by organisms (usually microbes) which induce carbonate precipitation through their metabolism.
What is carbonate deposition?
Depositional environments. Carbonate sediments accumulate in depositional environments that range from tidal flats to deepwater basins. Most carbonate sediments originate on a shallow-water platform, shelf, or ramp and are transported landward and basinward.
What are carbonates in geology?
Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals. The two major types are limestone, which is composed of calcite or aragonite (different crystal forms of CaCO3), and dolomite rock (also known as dolostone), which is composed of mineral dolomite (CaMg(CO3)2).
What are shelf carbonates?
Definition: A type of carbonate platform that is attached to a continental landmass and a region of sedimentation that is analogous to shelf environments for terrigenous clastic deposition. A carbonate shelf may receive some supply of material from the adjacent landmass.
Where are carbonate platforms found?
The reef
The reef is the rigid structure of carbonate platforms and is located between the internal lagoon and the slope, in the platform margin, in which the framework produced by large-sized skeletons, as those of corals, and by encrusting organisms will resist wave action and form a rigid build up that may develop up to sea- …
What is a platform in geography?
In geology, a platform is a continental area covered by relatively flat or gently tilted, mainly sedimentary strata, which overlie a basement of consolidated igneous or metamorphic rocks of an earlier deformation. Platforms, shields and the basement rocks together constitute cratons.
What is micrite and sparite?
If one compares the two classifications, a Rock rich in carbonate mud is termed a micrite by Folk and a mudstone or wackestone by Dunham. Moreover, a Rock containing little matrix is termed a sparite by Folk and a grainstone or packstone by Dunham.
What is a hydrogenous sediment?
Hydrogenous sediments include evaporites, meaning any type of sediment that forms from the evaporation of seawater. As seawater evaporates, the ions that remain behind can become so concentrated that they will combine with one another to form crystals that precipitate.
What is a homoclinal ridge?
A homoclinal ridge or strike ridge is a hill or ridge with a moderate, generally between 10° to 30°, sloping backslope. Its backslope is a dip slope, that conforms with the dip of a resistant stratum or strata, called caprock.
What is the meaning of ramp?
Definition of ramp (Entry 1 of 5) 1 : a sloping way or plane: such as a : a sloping floor, walk, or roadway leading from one level to another
What is a distally steepened ramp?
In distally steepened ramps, a distal step is formed between the middle and outer ramp, by the in situ accumulation of gravel-sized carbonate grains These factories are characterised by abiotic precipitation and biotically induced precipitation.
What is the difference between outer and middle ramp?
In the outer ramp, below the storm wave base, fine sediments may accumulate. In distally steepened ramps, a distal step is formed between the middle and outer ramp, by the in situ accumulation of gravel-sized carbonate grains (e.g., rhodoliths) only episodically moved by currents.