Monday, 19 April 2010

May 1st - Tintern Quarry

A visit to Tintern Quarry - Saturday May 1st
Leader: David Owen, Head of Geology, Gloucestershire Geology Trust
Tintern Quarry exposes the thickest section of Carboniferous Limestone in the area. The quarry face itself is some 400 ft high, with several benches and haul roads. In the base of the quarry is the Lower Dolomite which has some good dolomite crystals in it. A forestry track circling the quarry provides safe and easy access to a full sequence from Lower Dolomite, through Crease Limestone, Whitehead Limestone, Lower Drybrook Sandstone, Drybrook Limestone and Upper Drybrook Sandstone.
The junction between Lower Dolomite and Crease Limestone is uncertain in this area as dolomitisation has affected both units to a high degree. The Whitehead Limestone is variably porcelaneous, mudflake breccia and dolomitic mudstone, with many stromatolites and a significant palaeosol at the top. Lower Drybrook Sandstone is a coarse gritty sandstone but there are some curious features exposed in the track cutting that the leader will invite suggestions about. Drybrook Limestone is partly oolitic, partly porcelaineous and has palaeokarst within it (nearby is an area of limestone pavement which we could visit if we have time).
Meet at 10.30 am at Tintern Quarry (SO 550 984) Please wear stout walking shoes and suitable outdoor clothing. Bring a packed lunch.
This trip is organised by the Bath Geological Society - free to members of Bath GS, WEGA and Bristol NATs. Visitors £2 - everyone welcome. Please contact the field secretary so he knows to expect you - 07712 776117.

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