Carneal
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Geology & landscape
Geological Feature: Igneous Intrusion · Geological Period: Cretaceous, Paleogene · Rock Type: Basalt, Limestone
Landscape processes: Volcanic / Igneous
Description
Carneal Mineralogy Cameal is of importance because of its geology. Specifically the site contains rocks demonstrating the interaction between several rock types. An unusual range of minerals were formed by the intrusion of a Palaeogene age dolerite plug into the local Ulster White Limestone. There are only some 25 known sites worldwide where geochemical interactions of the type seen at Cameal occur. The central geological feature at this site is known as the Cameal Plug. Tbe dolerite plug intrudes the Lower Basalt Formation but has also dragged up a block of the older Cretaceous limestone from depth. The margins of the limestone were altered to calc-silicate rock containing spurrite and other minerals, while the adjoining dolerite was altered by the assimilation of limestone resulting in formation of coarse black pyroxenite and mixed pyroxene-Iamite rocks. A range of unusual minerals have been recorded from Cameal including calcite, lamite, spurrite, bredigite, melilite, spinel, titanaugite, wollastonite and the brown gel-like alteration product plombierite. Tobennorite is also reported from the locality. Cameal is one of a small number of important mineralogical sites featuring calc-silicate mineral assemblages, which were first described in the 1930s, most notably from nearby Scawt Hill. Such sites are of importance as they demonstrate how, at least on a small-scale, geologically distinct end products can be generated by assimilation ofand interaction between different rock types. https://www.daera-ni.gov.uk/publications/carneal-assi