The BGS Lexicon of Named Rock Units — Result Details
Dart Formation
Computer Code: | DART | Preferred Map Code: | DA |
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Status Code: | Full | ||
Age range: | Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ) | ||
Lithological Description: | Medium-grained gritty psammites and intercalated slightly graphitic mica schist. | ||
Definition of Lower Boundary: | Conformably overlying rocks of the Dungiven Formation (q.v.) | ||
Definition of Upper Boundary: | Overlain conformably by rocks of the Glenelly Formation (q.v.). | ||
Thickness: | c.2.5km | ||
Geographical Limits: | Dart Mountain and South Sperrins, Co. Londonderry, Northern Ireland. | ||
Parent Unit: | Argyll Group (ARGY) | ||
Previous Name(s): | Dart Formation [Obsolete Code: Use DART]
(DCDF)
Dart Formation [Obsolete Entry: Use DART] (DCDS) Dart Formation [Obsolete Name and Code: Use DART] (-2137) Schistose Grit Group of Dart [Obsolete Name and Code: Use DART] (-3346) |
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Alternative Name(s): | none recorded or not applicable | ||
Stratotypes: | |||
Reference Section | Butterhope Glen to 500m south east of Drumnaspar Bridge. | ||
Partial Type Section | Boundary stratotype, top of formation: Oughtboy Burn. Transition from medium-grained gritty psammites and graphitic mica schists (Dart Formation) to silvery green semi-pelite, flags and tourmaline schists (Glenelly Formation). | ||
Partial Type Section | Boundary stratotype, bottom of formation: green beds (amphibolitic) above uppermost limestone unit of Dungiven Formation, Butterhope Glen. | ||
Reference(s): | |||
Arthurs, J W. 1976. The geology and metalliferous mineral potential of the Sperrin Mountains area. Geological Survey of Northern Ireland, Special Report No. 1, 119pp, 2app, 2 figs, 7 tables, 102 maps. | |||
Hartley, J J, 1938. The Dalradian rocks of the Sperrin Mountains and adjacent areas in Northern Ireland. Proceedings of the Royal Irish Academy, Vol.XLIV, section B, 141-171. | |||
1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
none recorded or not applicable |