Humberside Geologist No. 13
Report of Hull Geological Society field trip to Derbyshire, Summer 2000.
By Felix Whitham.
On Saturday 10th June 2000, there was a field trip to Castleton, Derbyshire to visit the Blue John Mines, Treak Cavern and to examine the rocks and minerals of the area including the Carboniferous Limestones and Reef Knolls, also the shales and sandstones of the Millstone Grit Series which are well exposed in the area. The leader and Mini-bus driver was Terry Rockett
A group of 11 members of the Hull Geological Society set off at 9 a.m. from the University of Hull car park by Mini-bus on a fine sunny day bound for Castleton. After an uneventful but pleasant 2 hour journey via Sheffield the party arrived at the Blue John Mines set in an area of outstanding beauty about 11 am.
The Blue John Mines comprise a series of extensive underground water worn and partly mined caverns cut in Lower Carboniferous Limestone of Dinantian age. Members of the Society spent a very interesting hour underground led by a well informed local guide who described some of the very large caverns, and the very narrow- fissures which had to be negotiated to gain access to other caves. The guide highlighted many features, some naturally occurring at the same time pointing out some of the incredible feats of endurance by early miners working only with candle light to extract minerals from extremely difficult and dangerous areas high in the roof of the caverns or in the very narrow and deep water worn fissures at the base-
Emerging from the mine at mid-day members re-boarded the bus and were driven by Terry on a circular tour of the area. Terry also pointed out various geological features including the impressive Carboniferous Limestone crags in Winnats Pass and the massive face of Mam Tor exhibiting numerous beds of sandstones and interbedded sands of the Millstone Grit Series.
Returning to Castleton lunch was taken and a pleasant hour spent visiting the local shops viewing the wide range of fossils and minerals on display. After lunch a short drive was taken to Treak Cliff Caverns and here again well presented displays of local minerals and fossils were offered for sale. After a short break the party ascended Treak Cliff via a steep path which traversed Carboniferous Limestone and associated Reef Knolls. Fossils were fairly common in the loose flaky limestone path and included bivalves, brachiopods and crinoids. After a strenuous climb to reach the summit, Terry pointed out the various geological features of the area including some of the magnificent peaks. Although hammering is not permitted, fossils were quite common lying loose in rain washed gullies cut in the reel-knoll limestone. The following fossils were collected: brachiopods - Productus? llangollensis, Martinia glabra, 3 species of Rhynchonella; gastropod - ? Soleniscus acutus; corals - ? Amplex sp. ; crinoids Woodocrinus sp. ; bivalve - Posidoniella sp. ; Terebratulid - ? Hastata sp. and a fragment of a trilobite.
Afternoon tea was taken at Treak Cavern Cafe before setting of for the final visit of the day to Stannage Edge, a massive outcrop of Millstone Grit, a coarse grit stone with many quartzite pebbles, used in the past for carving out windmill corn grinding stones. Several beautifully carved examples were exhibited on the slopes towards the top of the outcrop. The view from the top of Stannage Edge was absolutely magnificent in the late afternoon sunshine. A leisurely drive back to Hull followed, arriving back at the University car park about 8 pm. Many thanks to Terry for a truly well organised outing and a pleasant and careful drive.
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