| 词条 | Ravenscar Group |
| 释义 |
| name = Ravenscar Group | image =File:Looking towards Herbert Hole - geograph.org.uk - 597749.jpg | caption =Sandstones and mudstones of the Saltwick Formation exposed on the cliffs near Herbert Hole, south of Ravenscar, North Yorkshire | type = Group | age = Middle Jurassic {{fossilrange|Aalenian|Bathonian|Aalenian to Bathonian}} | period = Middle Jurassic | prilithology = sandstone | otherlithology = mudstone, limestone, ironstone, coal | namedfor = Ravenscar | namedby = | region = | country = England | coordinates = | unitof = Cleveland basin | subunits = Saltwick Formation, Eller Beck Formation, Cloughton Formation, Scarborough Formation and Scalby Formation | underlies = Cornbrash Formation | overlies = Dogger Formation | thickness = 114m to c240m | extent = North Yorkshire | area = | map = | map_caption = }} The Ravenscar Group is a Jurassic lithostratigraphic group (a sequence of rock strata) which occurs within the Cleveland Basin of North Yorkshire and extends to both the Hambleton and Howardian Hills. The name is derived from Ravenscar on the North Yorkshire coast where rocks of this age occur. It was earlier known as the 'Middle Jurassic Series'.[1][2] It is the stratigraphic equivalent to the Inferior Oolite Group and most of the Great Oolite Group, being overlain by the Cornbrash Formation of the latter unit. References1. ^http://www.bgs.ac.uk/Lexicon/lexicon.cfm?pub=RAG {{UK-geologic-formation-stub}}2. ^British Geological Survey 1;50,000 scale geological map sheet (England and Wales series) no 34 Guisborough 4 : Aalenian Stage|Geology of North Yorkshire|Bajocian Stage|Bathonian Stage |
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