Ben Crom () is a mountain in the

Mourne Mountains The Mourne Mountains ( ; ), also called the Mournes or the Mountains of Mourne, are a predominantly granite mountain range in County Down in the south-east of Northern Ireland. They include the highest mountain in all of Ulster, Slieve Donard ...

County Down County Down () is one of the six counties of Northern Ireland, one of the nine counties of Ulster and one of the traditional thirty-two counties of Ireland. It covers an area of and has a population of 552,261. It borders County Antrim to the ...

Northern Ireland Northern Ireland ( ; ) is a Countries of the United Kingdom, part of the United Kingdom in the north-east of the island of Ireland. It has been #Descriptions, variously described as a country, province or region. Northern Ireland shares Repub ...

. It is situated beside

Ben Crom Reservoir Ben Crom Reservoir is a reservoir located in the Mourne Mountains near Kilkeel, County Down, Northern Ireland. Along with Silent Valley Reservoir, which is situated further down the Kilkeel River valley, it supplies water for County Down, surroun ...

, which is upstream from

Silent Valley Reservoir The Silent Valley Reservoir is a reservoir located in the Mourne Mountains near Kilkeel, County Down in Northern Ireland. It supplies most of the water for County Down, surrounding counties and most of Belfast. It is owned and maintained by Northe ...

. The mountain is composed of

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

. An exposed area on the south west of the mountain shows where the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

aplitic granite meets the

laccolith A laccolith is a body of intrusive rock with a dome-shaped upper surface and a level base, fed by a conduit from below. A laccolith forms when magma (molten rock) rising through the Earth's crust begins to spread out horizontally, prying apart ...

top of the older

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

granite

ring dike A ring dike or ring dyke is an Intrusive rock, intrusive igneous body that is circular, oval or arcuate in plan and has steep contacts. While the widths of ring dikes differ, they can be up to several thousand meters. The most commonly accepted me ...

. The summit of the mountain features granite crags which are crossed by basic and

feldspar Feldspar ( ; sometimes spelled felspar) is a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagiocl ...

porphyry Porphyry (; , ''Porphyrios'' "purple-clad") may refer to: Geology * Porphyry (geology), an igneous rock with large crystals in a fine-grained matrix, often purple, and prestigious Roman sculpture material * Shoksha porphyry, quartzite of purple c ...

dikes Dyke or dike may refer to: General uses * Dyke (slang), a slang word meaning "lesbian" * Dike (geology), formations of magma or sediment that cut through and across the layering of adjacent rocks * Dike (mythology), ''Dikē'', the Greek goddess ...

. The mountain is used for sheep grazing and hill walking. Silent Valley and Ben Crom from Slievenaglogh - geograph.org.uk - 1205677.jpg, View of Ben Crom (centre),

(bottom) and Ben Crom Reservoir (top right) from Slievenaglogh.

Slieve Bearnagh Slieve Bearnagh () is one of the Mourne Mountains in County Down, Northern Ireland. It has a height of . Its summit is crowned by two tors with a gap between them, giving it a distinctive shape. The Mourne Wall crosses the summit of Slieve Bea ...

is in the top left of the photo.

References

Mountains and hills of County Down Eocene magmatism Granite formations Ring dikes {{Down-geo-stub