The BGS Lexicon of Named Rock Units — Result Details

Gloddaeth Purple Sandstone Formation

Computer Code: GPS Preferred Map Code: notEntered
Status Code: Pending Upgrade
Age range: Westphalian Stage (CW) — Westphalian Stage (CW)
Lithological Description: Purple and red sandstone, cross-bedded with pebbly horizons. Warren et al., cite the Gloddaeth Purple Sandstone to be of Dinantian age, however, unpublished palynomorph assemblages obtained from a road cutting in the late 1980's by the Robertson Group, and which include the taxa Dictyotriletes birecticulatus and Endosporites globiformis, indicate an age no older than upper Westphalian A. The well preserved natuer of the assemblage suggested to the Robertson's palynologists that it had not been re-worked. Further investiation may allow the rank and parentage of the Gloddaeth Purple Sandstone to be revised. The possibility that it represents an early local facies of the Warwickshire Group cannot be discounted.
Definition of Lower Boundary: An unconformable contact with red and purple sandstone resting on massive to pseudobrecciated and locally dolomitised limestones of the Loggerheads Limestone Formation (Clwyd Limestone Group).
Definition of Upper Boundary: Not seen, presumed to be red and purple sandstone overlain by unconformable red Permo-Triassic sandstones of the Sherwood Sandstone Group.
Thickness: Over 23 thick.
Geographical Limits: Llandrillio-yn-Rhos area (SH 820 810), North Wales.
Parent Unit: Pennine Coal Measures Group (PCM)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Exposure 100m north of Bodysgallen, in purple sandstone resting on brown dolomite of the Loggerheads Limestone Formation (Clwyd Limestone Group). Warren et al., 1984. 
Reference Section  Old quarry 300m north of Bodysgallen, exposing 8.5 m of purple and grey sandstone with scattered pebbles. Warren et al., 1984. 
Reference(s):
Warren, P T, Price, D, Nutt, M J C and Smith, E G. 1984. Geology of the country around Rhyl and Denbigh. Memoir for 1:50 000 geological sheets 95 and 107 and parts of sheets 94 and 106. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E094