The BGS Lexicon of Named Rock Units — Result Details

Upper Matlock Lava Member

Computer Code: URB Preferred Map Code: URB
Status Code: Full
Age range: Brigantian Substage (CX) — Brigantian Substage (CX)
Lithological Description: Mainly vesicular and non-vesicular basalts. At Groaning Tor adit, Via Gellia (SK 283 572) the Member is seen as a 1m-thick clay wayboard (Walters and Ineson, 1981).
Definition of Lower Boundary: The basalt lava (or clay derived from weathered lava) of the Upper Matlock Lava Member rests upon thickly bedded limestones of the Monsal Dale Limestone Formation.
Definition of Upper Boundary: The basalt lava (or clay derived from weathered lava) of the Upper Matlock Lava Member is overlain by thickly bedded limestones of the Monsal Dale Limestone Formation.
Thickness: 36m thick in boreholes at Cawdor Quarry, Matlock (SK 285 605) (Smith et al., 1967)
Geographical Limits: The Member has a more restricted outcrop in comparison with the Lower Matlock Lava Member, extending from Tearsall Mine (SK 262 600) in the west to Masson Hill (SK 286 587) and the Derwent Valley (SK 296 587) in the east. The southernmost extent is Groaning Tor adit, Via Gellia (SK 283 572).
Parent Unit: Monsal Dale Limestone Formation (MO)
Previous Name(s): Matlock Upper Lava (-1898)
Upper Matlock Lava (-1899)
Matlock Upper Basalt (-3746)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Railway cutting south of High Tor, displaying 14m of basalt, amygdaloidal in upper 4.9m, possibly overlain and underlain by clay (weathered basalt). Smith et al., 1967. 
Reference(s):
Walters, S G and Ineson, P R. 1981. A review of the distribution of and the correlation of igneous rocks in Derbyshire, England. Mercian Geologist, Vol. 8, 81-132. 
Aitkenhead, N, Chisholm, J I and Stevenson, I P. 1985. Geology of the country around Buxton, Leek and Bakewell. Memoir of the British Geological Survey, England and Wales Sheet 111. 
Smith, E G, Rhys, G H and Eden, R A. 1967. Geology of the country around Chesterfield, Matlock, and Mansfield. Memoir of the Geological Survey of Great Britain. England and Wales Sheet 112. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E111 E112