Two 1-day field courses. These are independent of each other – enrolment can be on either, or both courses, according to interests / availability.
Tutor: Dr Nick Chidlaw
Saturday 20th and Sunday 21st July 2019
10.00 am – 5.00 pm each day
ICE AGE & HOT DESERT: TWO GEOLOGICAL WALKS NEAR GLOUCESTER Saturday 20th July
The Severn Valley immediately north of Gloucester comprises a rural landscape of farmland and scattered villages, punctuated by abrupt, flat-topped hills, and extensive tracts of valley floor over which the tidal rivers flows south. The geological history of the area is fascinating and contrasting. The oldest strata, c. 200 million year old, were laid down in hot deserts which gave way to shallow tropical seas; they can be seen in a cliff along the river. The hill tops preserve glacial deposits, and on the valley sides below is found a legacy of past valley floors now remaining as a series of ‘terraces’, as the river progressively incised its course. These hill top and terrace deposits were laid down during the Ice Age of recent geological time. Towards the end of the last glaciation, the river here was flowing in a ravine below its present level. With the ending of the Ice Age some 10,000 year ago, and the associated rise in sea level, the river has built up its broad clayey plain, frequently prone to hazardous winter floods. This course comprises a morning walk (c. 4 miles) and an afternoon walk (c. 3 miles), both gently-paced with frequent stops to discuss the geology and landforms.
A GEOLOGICAL WALK IN ESCARPMENT COUNTRY, MID COTSWOLDS: Jurassic strata and landforms near and far Sunday 21st July
The steep escarpment of Jurassic rocks in the mid Cotswolds looks north-west across the broad low-lying Severn Vale, to the Welsh Borderland hills and beyond. This mainly rural, highly attractive landscape overlies a geological legacy of repeated tectonic plate collision and extension, uplift and erosion, going back to Precambrian times. On this course you can learn to recognise these landforms, know of their underlying geology and understand how both came into being. Walking c. 4 miles between Doverow Hill near Stonehouse across the valley of the River Frome to Selsley Common, we examine exposures of Early and Middle Jurassic strata in old quarries and pits, and lane cuttings. These rocks, many of which are highly fossiliferous, were laid down in warm tropical seas overlying an active rift complex. In the Ice Age of recent geological times, the River Severn and its tributaries progressively incised their courses, and landslides occurred on the escarpment as it came into being; these landslides continued to take place, notably at the end of the last cold climatic episode c. 10,000 year ago, with some local movement continuing today.
Attached photograph is of Sandhurst Hill near Gloucester: this flat-topped hill (88m OD) has a veneer of glacial till and associated outwash deposits, laid down by a glacier during the Anglian Glaciation (480,000 – 420,000 years ago). Sandhurst Hill is a remnant of what was the valley floor of the Severn Vale at that time, since deepened by erosion to its present level.
No prior knowledge of geology, or the areas to be studied, is assumed. Attendees arrange their own travel, and if they do not live locally, arrange their own meals and accommodation – tutor can advise.
Meeting locations provided to those enrolled.
Volunteer drivers will be needed to facilitate the planned walking on both courses – please indicate if you would be willing to be a volunteer driver when enrolling
Tuition fee £27.00 per person per course.
If you/ anyone else you know would like to attend either or both these courses, please forward cheque payable to me to:
Dr N Chidlaw
8, Silver Street,
Dursley,
Glos.
GL11 4ND
Bank trans can be arranged if you do not use cheques – let me know.
Please provide me with your postal address – I will then be able to send you your course handout(s) in good time before the courses run, should they become viable.
Deadline for minimum number (10) of enrolments for both courses is Saturday 18th May. Maximum number of enrolments is 30. If the minimum of enrolments for either or both courses is reached by this deadline, arrangements will continue; if not, the course / courses will be cancelled and fees received will be returned soon afterwards to those who have sent them in. Once viable, enrolments on the course can continue up to 1 week before they are due to run (Saturday 13th July)
Any queries, contact tutor nickchidlaw@gmail.com
