Articles from Issue Number 9/3 June 2002

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S260/SXR260 FIELD TRIP TO HERNE BAY 23rd March 2002

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Guildford and the Hogs Back Geowalk Sunday 28th April 2002

S260/SXR260 FIELD TRIP TO HERNE BAY with
MEMBERS of the LOUGS
23rd March 2002


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A bright sunny day plus the infectious enthusiasm of our leaders set the scene for the whole of our day. We started out on to Beltinge Beach and due to numbers split into three groups.

There was plenty to see and I felt sorry for the general public using the beach as they had little idea of what wonders surrounded them. Our first clues were the shingle beach itself, a veritable mixed bag of different deposits. Newcomers, like myself, were introduced to the technicalities of grain size, rounding and "chatter" marks etc.,and how it all related to events long ago (geologically speaking of course).

We could see for ourselves how the coastline was receeding, the evidence including the fact that the remains of a Roman Fort, which was once far inland, was now at the cliff edge at Reculver.

Modern man is trying to prevent further erosin by various means. A curved concrete promenade wall has been built along the beach, plus large blocks of imported stone dumped at the top of the beach. These stone blocks gave us further opportunity to try out our skills in typing and dating rocks. Reduction of the angle of the cliffs and drainage were also needed to delay erosion. This is particularly necessary here due to the presence of London clay. We were also told that, tectonically, the area is sinking.

Our leaders encouraged us to take a closer look at the cliffs and their structure. Features such as London clay, parallel bedding and the Upnor formation were pointed out.

We were lucky enough to finish the morning session back on the beach, with the tide out, to look for fossils. This was a very new revelation to me. Preserved burrows of long gone sea creatures were pointed out, and shells, which I would have dismissed as just sea shells were in fact incredibly delicate fossils. I believe we all came away with a sample.

As we made our way to Reculver for lunch and our afternoon session I reflected on the fact that I had climbed up and down the cliffs and seen things I had never noticed before. My whole outlook on beaches and cliffs will never be the same again. I shall be looking for that something extra, and I will want to know what that rock is and how those pebbles reached the beach. Truely an amazing day, and a big thank you to the organisers.

Frances Gregory

Following an interesting morning at Beltinge we moved further along the coast to Reculver. It was a bright, sunny afternoon - most unusual as far as field trips go – or so I am led to believe, as this was my initiation. After a pit stop at the King Ethelbert Inn we set about examining the imported rocks that make up the sea defences and looked for evidence of what they were. Thanks to Diana I now know what the twinkle factor is!

We then went on to look at the rebuilt Roman Fort and discuss the building materials used within it. The general consensus was that it is a real mish mash of rock types with no one predominant type. However, they are mainly local rocks. Among those which we identified were:

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Flint

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Concretions from the Thanet Formation showing cross stratification, some with heavy burrowing.

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Concretions from the Harwich Formation with well preserved shell material.

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Tufa, a cold water spring precipitate.

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Roman bricks.

And ……. there was much excitement when one of the more observant of the students spotted some Oolite limestone.

Our thanks must go to all those involved in the organisation for a very interesting day. The enthusiasm of all the tutors was infectious and their patience in answering our never-ending stream of questions was remarkable.

Eleanor Phillips

What a Difference a Year Makes

March 2001 OUGS field trip and I’m freezing cold in Walton on the Naze looking at London Clay. I’m about a month into S260 and I’m finding out fast I know next to nothing about geology. The fact is I’m stuck on the principal of dip and strike in the first book and wondering whether I should have taken physics instead.

Fast-forward one year.

March 2002 OUGS field trip and it’s a lovely spring morning in Herne Bay looking at London Clay and I’ve a passed S260 respectably. Now this doesn’t mean I know everything there is to know about Geology, in fact far from it. As a geologist I am just starting out. But I do feel much more comfortable with my ability to interpret what I observe and this is the key difference a year on. Rather than guessing as I did last year (and as some students were doing this year - yes we’ve all been there) I now have a method to follow, rather like Sherlock Holmes. This enables me to build up a picture of how rocks are formed, what processes were in action, and the possible environment where formation took place. Consequently, the clues that were invisible on last year’s field trip are now more apparent.

This year I’m looking back on S260 with a great amount of nostalgia, studying physics which I’m finding out I know next to nothing about and thinking that I maybe should have chosen chemistry instead!

Bob Tarff

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Guildford and the Hogs Back Geowalk
Led by Brian Harvey
Sunday 28th April 2002


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Thirty-five people and a dog gathered at Millmead in the centre of Guildford for this seven mile geowalk. We would explore the influence of geology on topography, land use; building stones, as well as attractive countryside with some interesting local history.

The Hog’s Back is a prominent Chalk ridge on the North Downs between Guildford and Farnham, forming part of the northern limb of the Weald anticline. The strata here were deposited under marine conditions during the Cretaceous Period. They young, and, therefore, dip, steeply northwards. Guildford is situated in the gap, cut by the River Wey, through the Chalk and Lower Greensand.

Beginning the walk along the river, Paul Hetherington and Janet Philips talked about the important transport links provided by rivers and canals before the coming of the railways. For example, building stones from the Weald, could be shipped down the Wey Navigation, linking Guildford to the Thames and London. Janet Philips, a representative of the Wey and Arun Canal Trust, talked about the link between London and the south coast, via the rivers Wey and Arun. Both rise in the Weald but flow in opposite directions.

Snaking along the towpath, we looked at building stones in a wall I had walked past many times. I now know that it is built from the Bargate Beds, a calcareous sandstone with poorly sorted grains of very variable size.

I had always been curious about St. Catherine’s Hill where some orange coloured sand slopes steeply down to the river. This comes from an outcrop of sandstone further up the hill: the Folkestone Beds, part of the Lower Greensand formation. The orange colour is produced by iron oxide, derived from chemical weathering of the glauconite.

Leaving the river, we began walking westwards along the Lower Greensand ridge towards Compton, noting differences in land use. The Folkestone Beds, produce acidic soils which are unsuitable for arable farming. Therefore, this land tended to be covered by woodland. The Gault Clay is now cultivated but, being a very heavy clay, it could not be farmed or drained until the invention of the steam plough in the mid nineteenth century.

Particularly before the coming of water and rail transport, a local source of building stone was essential. Just outside village of Littleton was a small quarry of Bargate Beds, commonly used in buildings in Guildford and London, including St.Paul’s cathedral. It only occurs in this part of the Weald as thin outcrops in the Lower Greensand. Carstone is also widely used. We saw this regularly today, including in the form of cross-bedding in the Folkestone Beds. It is a very hard iron-sandstone. The harder Chalk beds have been quarried for more decorative use in buildings, as clunch.

As the footpath entered the grounds of Loseley house, we moved from the Hythe Beds onto the impermeable Atherfield Clay where there was a lake – and some mud. This is the oldest marine deposit in the Weald, laid down when the sea poured in via the Bedfordshire Straits in the north west.

Had lunch in the pretty village of Compton, taking particular interest in the building stones at St. Nicolas church. This dates from Saxon times and has the oldest carved timber in the British Isles. Inside was a font, allegedly made out of carstone (probably not) and walls decorated with clunch.

I hadn’t realised that Compton also has a memorial chapel, built in 1898, on the hill above the cemetery. This was designed by the potter Mary Watts, the wife of Frederick Watts, the local artist from whom the Watts Gallery, in the village, takes its name. Seventy-three villagers helped build it. People have had mixed feelings about its Art Nouveaux style: the intricate carvings in the red brick outside and the colourfully painted Celtic designs on the walls and roof inside; but we considered it one of the highlights of the walk.

The geese in the farm kept their distance as we left Compton; heading into the woodland on the Folkestone Beds; before reaching the high ground of the chalk ridge. Chalk, a fine-grained limestone, is the youngest of the Cretaceous formations in the Weald. There are Lower, Middle and Upper layers, the Chalk becomes progressively purer with less and less clay content.

. The Upper layer also contains chert (flint). We tried to discern these changes as we climbed up the hill but were distracted by the heavy showers which had held off until now.

Fortunately, the heaviest rain had stopped by the time we reached the clearing in the trees at the top of the ridge. Here, there was a good view south over the Weald. We recognised some local landmarks and tried to visualise the underlying geology.

Ending the walk on the hill overlooking Guildford and the Tertiary sediments of the London Basin to the north, we thanked Brian for leading a highly informative and fascinating walk.

Joan Lee

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