The BGS Lexicon of Named Rock Units — Result Details

Cressbrook Dale Lava Member

Computer Code: CBDL Preferred Map Code: notEntered
Status Code: Full
Age range: Brigantian Substage (CX) — Brigantian Substage (CX)
Lithological Description: Typically comprises hyaloclastite, basalt and tuff, the latter locally with some limestone grains. At Cressbrook Dale the member is dominated by amygdaloidal basalt. At the type locality the lower part comprises brecciated lavas, with oxidised angular fragments of vesicular or non- vesicular basalt and a matrix of silica and chlorite, interdigitated with non-brecciated basalt lavas. At this locality, the top of the member is a 0.75m thick pale green, pyritic tuff
Definition of Lower Boundary: At the type locality, the basalt at the base of the member is underlain by dark grey cherty limestones of the Monsal Dale Limestone Formation.
Definition of Upper Boundary: At the type locality, the pale green tuff at the top of the member is overlain by dark grey biomicrosparite limestones of the Monsal Dale Limestone Formation
Thickness: Maximum thickness of 80.88m proved in the Longstone Edge Borehole, SK27SW/5 [SK 2088 7335).
Geographical Limits: The member has a limited poorly exposed outcrop at Cressbrook Dale (SK17 74), with a thicker and extensive development in the subsurface to the north and east of this locality.
Parent Unit: Monsal Dale Limestone Formation (MO)
Previous Name(s): Cressbrook Dale Lava (-4519)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Eyam Borehole, SK27NW/15: includes a 76.59 m thickness of basalt and brecciated basalt Dunham, 1973. 
Reference(s):
Dunham, K C. 1973. A recent deep borehole near Eyam, Derbyshire. Nature Physical Science, Vol. 241, 84-85. 
Stevenson, I P and Gaunt, G D, 1971. Geology of the country around Chapel-en-le-Frith. Memoir of the Geological Survey of Great Britain, England and Wales, Sheet 99. 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E099 E111