Geology Seminar 12 - Geological Maps Part 1

Virtually every second year geology degree student will spend several weeks of their summer vacation in the filed producing their own 1 to 10,000 scale geological map by overlaying geological information obtained from the study of outcrops in the field onto a 1 to 10,000 base map.  Nowadays modern technology has replaced paper at least in part but I image that paper field slips are still used to record the geology in the field for transfer to a clean back-up copy in the evening and eventual transfer to the final map.  This process has not changed for many years. UK students studying geology at GCSE or A-Level will also spend time learning about geological maps and using them, although the basics will be taught using simplified or idealised "cartoon maps" which have been prepared to demonstrate certain features.  Often these are based on real geological settings but they have been simplified because real geology is often far more complex and variable. 

The first geological map can be traced back to the ancient Egyptians and it shows several features that are used on modern geological maps such as those produced for the UK by the British Geological Survey.

In Seminar 12 I introduce geological maps an cover their history, focusing particularly on the history of maps in the UK, key features and their use.  In the final part I demonstrate through use of a cartoon (i.e. simplified) geological map how a student would go about constructing a geological cross section from the map on a blank template.

Those attending the seminar at the time of the drawing were given the cartoon map and blank section to have a go at completing the cross section as "homework".  I wait to see if anyone has a go.

Geology Seminar 7 - Palaeontology Part 1

Seminar 7 has now been re-recorded - required because there were problems with the recording file when I last ahve the talk to a live audience.

In Seminar 7 I introduce the subject of palaeontology, a topic which geology students spend a considerable proportion of the GSCE, A-Level or Degree Level geology courses studying.  I start by looking at the evolution of life on Earth including the Cambrian "Explosion".  I also look at the fossilisation processes and methods of preservation. 

The set of seminars produced to date includes several presentations on the major fossil groups, the first of which, the Trilobites, was covered in Seminar 8. 

Geology Seminar 10 - Geological Structures

Happy New Year to those viewing my blog.

Continuing the series of Seminars has resumed after the Christmas break.  Seminar No. 10 on Geological Structures has been delivered for the second time to interested Graduates within the company.

Within the category of Geological Structures I look at geological folds, faults and diapirs together with unconformities and non-conformities.


The sharp-eyed reader will have spotted that I still have not got round to posting recordings for Seminars No. 7 (which I promised to do previously) and No. 9 due to a lack of suitable recording for No. 7 and a perceived relative lack of interested in Palaeontology in the case of No. 9.  I am intending to record files for both and post them over the next few weeks.

Geology Seminar 19 - The Brachiopods

A seventh Seminar on Palaeontology looking at a fifth group of fossils, the Brachiopods.  These are a group of twin shelled marine organisms which were common in the Palaeozoic Era but declined during the Mesozoic Era until becoming rare in the present day as a result of competition with more successful life forms and no doubt climatic change.  Good indicators in the fossil record of shallow marine tropical conditions and intolerant of pollution in the present day.

Geology Seminar 8 - Palaeontology (The Study of Fossils) - Part 2

There was a problem with the recording file for Seminar 7, which was an Introduction to the subject of Palaeontology or the Study of Fossils, but the recording files for Seminar 8 - Palaeontology - Part 2 came out fine after holding the Seminar on 9th November at 12.30 (UK GMT). 

Seminar 8 has been delivered in two parts.  I start with a demonstration of some of the fossils in my own personal collection, most of which I have collected myself during various field trips from studying GSCE geology back in 1991 through to field trips in more recent years.  There are also a few fossils I have either received as gifts from relatives / friends and even a couple I have bought, either because I particularly liked the look of them or I knew I was not likely to be visiting anywhere to acquire an example myself or a combination of the two.  Most of the specimens are not of museum quality but are typical of the type of fossils you can (or could in some cases) collect from the various locations described.  Most if not all of the fossil groups represented in the slides will be talked about in more detail during subsequent Seminars on the topic of Palaeontology.

I should note, unless the collection locations are publicly accessible, e.g. beach locations in Dorset) and their is no ban on collecting specimens that any access or collecting should only be done with permission of the landowner.  Safety is also important, particularly with working and even closed quarries.  All visits to quarries, particularly working ones, was with permission and as part of a party of geologists. 

The second part of Seminar 8 looks at a group of fossils that were important during the Palaeozoic Era (Cambrian, Ordovician, Silurian, Devonian Carboniferous and Permian periods), say 542 to 252 Million years ago.  This is the Trilobites, a now extinct group of Marine Arthropods. 

Although out of sequence, Seminar 7 will be posted as soon as I get the file re-recorded on Lync.

The next planned Seminar will be another new one, number 19 which will cover The Brachiopods a group of marine twin-shelled organisms which may look superficially like bivalves (which are molluscs) but have a totally different morphology. 

St. Albans Sinkhole - Update

According to the BBC's web site today, the void which opened up at Fontmell Close at the beginning of the month has now been backfilled, but that geophysical surveys (gravity) below the surrounding roads and footpaths suggest that there is at least one other void in the same area.  A copy of the image showing the survey reuslts (corutesy Hertfordshire County Council via the BBC News Web Site) is shown at the bottom of this post.

It does also appear that the site is a former clay pit on which housing was later built.  It is suspected, as was the case in Reading (e.g. Field Road), that there has been mining of the Chalk below the clay pit and it is these mine workings that have collapsed leading to the formation of the void.

The next step is expected to be intrusive investigations to search for voids and back up the geophysical surveys. 

Backfilling the existing void apparently required 48 lorry loads of foamed concrete.  Sadly the residents closest to the now backfilled void have still not been able to return home due to ongoing safety concerns.