(S13) Carbonate Platforms Flashcards
What are the five different forms of carbonate platforms?
Homoclinical ramp, Distally steepened ramp, Unrimmed flat-top platform, Rimmed flat-top platform, Isolated flat-top platform
What is an “attached flat top platform”?
A very low gradient top connected to the continent, then a steep slope which is the front margin: Rimmed or unrimmed
What is the variation in size of an attached flat top platform?
Few km to >1000km
What is another name for an inland sea?
Epeiric sea
What is a rimmed platform?
Carbonate shelf with a reef or other carbonate body to act as a rim before the forereef slope
Give three examples of facies that a lagoon created by a rimmed platform may be associated with
Shoals, patch reefs, migrating island systems
Instead of reefs, unrimmed platform margins are often marked by the development of relatively high-energy facies such as ___.
Ooid shoals
Aside from the lack of reef system, what is the two main differences between a unrimmed and a rimmed carbonate shelf?
Unrimmed tend to have lower gradient margins, and a somewhat higher energy platform
What is the variation in size of an isolated flat top platform?
Few hundred meters to ~500km long
Give a modern example of a larger isolated flat top platform
Bahamas
What is the difference between a isolated flat top platform and a reef?
Isolated flat top platforms may be hundreds to km above the sea-floor depth which aggrigated before reef formation
What defines an asymmetrical isolated flat-top platform?
Well-developed rimmed margin on one side of platform - usually side with prevailing wind/ocean current favourable for reef growth
What forms at the leeward margin of an isolated flat-topped platform?
Grain-shoal islands
What forms at the windward margin of an isolated flat-topped platform?
Aggrading reef
What is the difference between ramp platforms and other carbonate platforms? (2)
Not flat-topped, do not have steep margin