| Computer Code: |
KVG |
Preferred Map Code: |
notEntered |
| Status Code: |
Full, without ratification |
| Age range: |
Eifelian Age (DI)
— Eifelian Age (DI) |
| Lithological Description: |
Spilitic lavas, tuffs, (dominantly) crinoidal limestone and mudstone (slate) comprise the lithologies within the Kingsteignton Volcanic Group. At the base of the succession, interbedded tuffs and slates with thin (< 0.3 m) lavas are succeeded by tuffs with subordinate lavas, mudstone (slate) horizons and limestone lenses up to 30 m thick. Lavas are commonly deeply weathered; in the upper part of the succession they are amygdaloidal or vesicular. Tuffs of the Kingsteignton Volcanic Group are spilitic, chlorite-rich with evidence of recrystallisation and development of secondary minerals. The tuffs are dark green when fresh, and brown to buff when weathered. Limestones in the lower part of the succession are dominantly crinoidal with layers of fine-grained thin-bedded limestones and massive stromatoporoid limestone; they form impersistent lenses that inter-digitate with tuffs. Crinoidal limestone with laminar and massive stromatoporoids are found higher in the sequence. |
| Definition of Lower Boundary: |
The Kingsteignton Volcanic Group occurs only in the Ugbrooke Unit (i.e. in the thickness of rock that is bound by the Bickington Thrust in the north and by the Ware Barton Thrust in the south); within this Unit it has a conformable boundary with the stratigraphically lower Nordon Slate; the sequence is inverted where it is exposed in an old quarry at [SS 8993 7372]. The contact between the Kingsteignton Volcanic Group and the Norden Slate is characterised by a transition from a sequence of greenish-weathering black or bluish-grey slates with local interbeds of dark grey / black limestones in which the bedding is obscured by cleavage, with local spilites, tuffs and small intrusions of dolerite to the rock types characteristic of the Kingsteignton Volcanic Group, as described in the the lithology description above. |
| Definition of Upper Boundary: |
The top of the Kingsteignton Volcanic Group is conformable with the overlying Chercombe Bridge Limestone Group. |
| Thickness: |
0 to 105 m. |
| Geographical Limits: |
Teign Estuary area, south Devon. |
| Parent Unit: |
Not Applicable (-)
|
| Previous Name(s): |
Volcanic Rocks and Greenstones
(VRGN)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Chudleigh, Devon. |
| Reference(s): |
| Ussher, W A E. 1913. Geology of the country around Newton Abbot. Memoir of the British Geological Survey, Sheet 339. (England and Wales). |
| Selwood, E B, Edwards, R A, Simpson, S, Chesher, J A, Hamblin, R J O, Henson, M R, Riddolls, B W and Waters, R A. 1984. Geology of the countryside around Newton Abbot. Memoir of the British Geological Survey, Sheet 339 (England and Wales). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E339
|
