Dorset Geologist’s Association Group (DGAG) will host a talk on the Tuesday 21 November 2023.
Title: Aspects of the geology of the Hampshire Basin – an idiosyncratic view
Speaker: Tony Cross with an educational and entertaining talk on a “basin scale” that will be a mix of geology and human history. A talk to get everyone thinking of our place in history and geology!
Time: Talk will start at 7pm; finish approximately 8pm
Venue: Activity Meeting Room: Dorford Centre, Bridport Road, Dorchester, DT1 1RR
Lecture Entry Cost: £6 (£5 for DGAG members) collected on room entry
Booking a seat: Contact DGAG events at email: cwebb48578@aol.com
Talk Description: ‘A conscientious scientist who gives a title like this must feel that his chief debt is to the contemporaries and predecessors who actually did the work and made the discoveries’ – this paraphrases Derek Ager (1923–1993) whose book Introducing Geology (1961) started the speaker on a geological journey that has lasted a lifetime. Having been born and raised in Dorset, Tony Cross was drawn to what was on his doorstep and maintained an interest in the geology of his own county despite pursuing a career in the earth sciences which took him to many faraway places. This talk is a personal look at Dorset’s geology from many different viewpoints reinforcing the notion that what is under one’s feet is much more than an academic subject few have the opportunity to study
Photos: Courtesy of the speaker; Lulworth Cove – historical, Swanage Churchyard
Dorset Geologist’s Association Group (DGAG) will host a talk on the Tuesday 17 October 2023.
Title: Geoarchaeology of puddingstone in Hertfordshire and Dorset
Speaker: Mervyn Jones with a talk mixing in archaeology with geology. The talk is based on a recent publication co-authored by the speaker in the Proceedings of the Geologists’ Association in Feb 2023.
Time: Talk will start at 7pm; finish approximately 8pm Venue: Activity
Meeting Room: Dorford Centre, Bridport Road, Dorchester, DT1 1RR
Lecture Entry Cost: £6 (£5 for DGAG members) collected on room entry
Booking a seat: Contact DGAG events at email: cwebb48578@aol.com
Talk Description: Discontinuous lenses of pebbly conglomerate have been silicified to create concretions of Hertfordshire Puddingstone. These 2–3 m of Paleogene silt-sand and gravel draping the Chalk were investigated using geological and archaeological techniques. Dissolution features in the chalk created 93 dolines, the largest concentration in the Chilterns. These were exploited by the Romans as valuable raw material for quern-making. Shortly after the Roman Conquest in AD43 the site was cleared by felling and burning the tree cover. The cortex and poor-quality core stone were cut away from concretions with picks, manageable slices were detached using steel wedges and initial shaping was undertaken to produce blanks of querns to be finished elsewhere. Quarrying continued for, at most, fifty years. The excavated doline fills and rims around the pits taken together form the second largest remaining area of Roman ground surface in Hertfordshire. The site was abandoned and has been largely undisturbed apart from some quarrying of chalk and brickearth and offers further opportunities for research. These findings will be contrasted with the pebbly Sarsen of Dorset and its use by neolithic people, including the recent discovery of a polissoir (“polishing boulder”) in the valley of stones – see https://www.dorsetaonb.org.uk/news/polissoir
Photo: Screen shot photo courtesy of Wikipedia https://en.wikipedia.org/wiki/Hertfordshire_puddingstone
References Website links:
Feb 2023 https://www.sciencedirect.com/science/article/abs/pii/S0016787822000815
2006 https://www.researchgate.net/publication/283763995_Ancient_quarrying_of_rare_in_situ_Palaeogene_Hertfordshire_Puddingstone
