The BGS Lexicon of Named Rock Units — Result Details
Dart Formation
| Computer Code: | DART | Preferred Map Code: | DA |
|---|---|---|---|
| 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) |
||
| 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 | |||