1 Day Field Course with Nick Chidlaw

Nick wanted to run this course in early October; there were enough people who wanted to go on the course but there was difficulty with the date. So he is going to run the course on Sunday the 5th March. Nick has contacted the people who expressed an interest in the October date, but if you want to join, I am sure Nick can find a place for you. All you need to know is in Nicks advertisement which is below.

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  A CIRCULAR WALK IN SOUTH GLOUCESTERSHIRE: shallow tropical seas and rivers, ice age valley incision 

Sunday 5th March 2023   10.00 am - 5.00 pm

The generally low-lying landform of much of the county of South Gloucestershire is interrupted near the village of Cromhall by a steep sided, narrow meandering valley lined by rocky crags. The base of the valley was dammed in the 19th century to form a 700m+ long lake, part of the grounds of Tortworth Court (now a hotel). Some 40m deep, the valley is short: indistinguishable from the surrounding countryside only 2 miles to the south of the lake, and likewise so in the open ground on the lake’s north-west side. The stream that feeds and exits the lake is small, and is a ‘misfit’, occupying a valley cut by much more powerful waters during the ice age. Rock exposures, including the natural crags, track cuttings and old quarry workings provide an opportunity to examine the local character of successive stratigraphic units of the Carboniferous Limestone Supergroup. The strata dip 20 – 30 degrees to the south and south east, demonstrating the structural contrast between that found north and south of the ‘Variscan Front’ in the Bristol area, established by the end of the Carboniferous period some 300 Ma. No previous knowledge of geology or the area will be assumed.   

 

A handout outlining the day’s programme, including location sketch map, geological map and cross section, illustrated geological history and written log of the succession of strata, will be forwarded in advance of the course to those enrolled.

Note that enrollees will need to:

*     Arrange their own transport

*     Bring a packed lunch and any refreshments (e.g. flask of coffee, fruit juice, mineral water etc.)

*     Wear strong footwear with good tread and ankle support, and have waterproof clothing if weather is poor.

*     There will be no requirement to wear hard hats on this course. 

Attendees will be insured against accident for the duration of the course. 

Tuition fee: £30.00 

Contact tutor Dr Nick Chidlaw nickchidlaw@gmail.com to enrol and for any queries. 

Deadline for course viability: Friday 6th January. If the course has become viable (minimum of 10 enrolments) by this date, enrolments will be able to continue until 1 week (Sunday 26th February) before the course runs..   

Google Earth oblique image of the study area, looking south showing the abruptly-incised meandering valley and lake near the village of Cromhall. 

Track cutting in the Cromhall Sandstone Formation (Middle part). The character of the Carboniferous Limestone Supergroup changes notably between South Gloucestershire and the Mendips; in this area in the north, reddish quartz sandstones and mudrocks, deposited in rivers, occupy much of its upper part and are virtually absent in the south.