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Mixed Clastic–Carbonate Cycles and Sequences: Quaternary of Egypt and Carboniferous of England

M.E. Tucker

Sažetak

There are various types of mixed clastic–carbonate sequences and parasequences in the geological record and sea-level change is one of the major controls on their development, as well as the obvious availability of terrigenous material. Mixed-lithology sequences are especially well-developed in icehouse times, as in the Permo–Carboniferous and Quaternary. The two major types, lower carbonate–upper clastic and lower clastic–upper carbonate sequences, reflect the rates of sea-level change and the source of clastic sediment – whether it is brought across the carbonate platform from the adjacent landmass or supplied axially to the basin. Two examples of carbonate–clastic high-frequency sequences are discussed: 1) from the Red Sea coast of Egypt, Quaternary transgressive/highstand shallow-water carbonates and late highstand/falling-stage/lowstand clastics deposited in incised-valley fills and fan deltas, and 2) from northern England, mid-Carboniferous ‘Yoredale’ cycles of transgressive shelf carbonates passing up into highstand coarsening-up deltaic and shoreline clastics, capped by palaeosoils and coal. Locally, falling-stage incised-valleys supplied sediments to the adjoining basin. One significant difference between these two examples is the palaeoclimate: arid in the Red Sea leading to the episodic supply of sand and gravel, and humid in the Carboniferous resulting in the more continuous supply of mud and sand, each having a different effect on carbonate deposition.

Ključne riječi

Clastic–carbonate interaction; Sequences; Cycles; Quaternary Red Sea; Egypt; Yoredale cyc­les; Carboniferous cycles; England

Hrčak ID:

3789

URI

https://hrcak.srce.hr/3789

Datum izdavanja:

27.6.2003.

Posjeta: 5.479 *