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Ravenstonedale Group
The Ravenstonedale Group is a Carboniferous lithostratigraphic group (a sequence of rock strata) in the Pennines of northern England. The name is derived from the locality of Ravenstonedale in southeast Cumbria. The rocks of the Ravenstonedale Group have also previously been referred to as the Ravenstonedale Limestone. The group comprises limestones and oolites and some sandstones and shales which reach a maximum thickness of 380m in the Brough area. It is divided into a lower Raydale Dolomite Formation which is overlain by the Marsett Formation and then by an upper Penny Farm Gill Formation.Its base is everywhere an unconformity An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval o ... with Ordovician and Devonian rocks beneath. References * {{Refend Carboniferous System of Europe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group (stratigraphy)
In geology, a group is a lithostratigraphic unit consisting of a series of related formations that have been classified together to form a group. Formations are the fundamental unit of stratigraphy. Groups may sometimes be combined into supergroups. Groups are useful for showing relationships between formations, and they are also useful for small-scale mapping or for studying the stratigraphy of large regions. Geologists exploring a new area have sometimes defined groups when they believe the strata within the groups can be divided into formations during subsequent investigations of the area. It is possible for only some of the strata making up a group to be divided into formations. An example of a group is the Glen Canyon Group, which includes (in ascending order) the Wingate Sandstone, the Moenave Formation, the Kayenta Formation, and the Navajo Sandstone. Each of the formations can be distinguished from its neighbor by its lithology, but all were deposited in the same vast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
