21st June 2017 – Lymm Dam Geology Walk

Pre-walk Briefing

Pre-walk Briefing

Leader Fred Owen gathered a group of SciBarians at the Lymm Dam car park for a briefing on the geological history of the area.  He explained that Lymm is situated in the centre of the northern part of the Cheshire Basin, which is one of a series of basins extending from the east Irish Sea to the English Channel. The sediments filling the basin are the familiar red sandstones eroded from a mountain range of Himalayan proportions about 230 million years ago, when the ‘English’ tectonic plate was roughly where the Sahara Desert is today. It would have been in an inland, arid desert climate, on a super-continent on the north of the mountain range. The south east of the Cheshire Basin would have been deep enough to bury the Matterhorn.

Tarporley Siltstone

Tarporley Siltstone

Later earth movements caused the sea to transgress the desert to form finer inter-tidal sediments, known as the Tarporley Siltstone, which were seen at the southern end of the lake. Today’s picturesque landscape around Lymm Dam was formed during the last Ice Age, by a combination of erosion by glacial ice and glacial melt-water around 20k to 10k years ago. The ice, 200m or more thick, flowing from the northwest, scoured out the gorge now occupied by the lake formed when the dam was built in 1824 on the site of a 3 meter waterfall in the Bradley Brook.

Meltwater Channels

Meltwater Channels

The group examined a remarkable set of seven deep, narrow, sinuous channels cut into the red Helsby Sandstone, which were aligned more or less parallel to the ice flow direction.  It is deduced that they were cut by melt-water below the water table, known as ‘phreatic’ water. Less obvious were five horizontal channels at right angles to the deep ones, believed to have been eroded later by melt-water above the water table, known as ‘vadose’ water. The only other example of such channels in England is at Thurstaston on the Wirral.  An alternative hypothesis has been proposed that these ‘melt-water’ channels were really formed by children with trainers and mountain bikes!

Vertical ‘scallops’

Vertical ‘scallops’

Further along the path a sandstone outcrop exhibited numerous vertical, elongate ‘scallops’ eroded into the sandstone, believed to have been formed by turbulent, phreatic melt-water flowing between active ice and the rock face.

Fred reflects: “It was interesting that here we were standing on the longest day in real-time on the edge of a temperate thunderstorm, on sandstone formed in an arid dessert, observing channels cut under 200m of ice by melt-water. Climate is always changing! The real issue is the rate of the change to which life can adapt to survive.”

In answer to a specific question about tectonic plate thickness Fred explained that oceanic plates are about 7 km thick while continental plates average 35 km thick. Oceanic crust is much denser than continental crust so is repeatedly ‘subducted’ beneath continents and recycled. It has a maximum ‘lifespan’ of 200 million years. There is an excellent free app ‘Earthviewer’ which shows how the plates have moved over geologic time and gives much information about fossils, mass extinctions etc.

The walk concluded with a convivial meal at the Spread Eagle in Lymm village.

Thanks to Fred for conducting the walk and for writing this blog entry.

For further reading, Fred suggests “Leviston, D. 2001. Subglacial meltwater channels at Lymm Dam, Cheshire. Proceedings of the Geologists’ Association, 112, 147-154.”

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5th June 2017 – Mersey Gateway

Mersey Gateway

Keith Bold Portrait

Keith Bold will tell the story of one of the largest construction projects in the UK.

Work started on the Mersey Gateway Project on 7th May 2014 and in autumn 2017 a new six lane toll bridge over the Mersey between the towns of Runcorn and Widnes will open to relieve congestion on the ageing Silver Jubilee Bridge.

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29th May 2017 – Lions Centenary Fair

Play Day Rocket

Play Day Rocket

The photo above is from a previous big rocket event, held as part of Playday, organized by Friends of the Moor. Please note that Friends of the Moor have said they will NOT be running Playday this year.

Three Two One!

Three Two One!

Update (June 2nd): The Lions Fair was all round a very successful event. There were lots of activities, the threatened rain did not materialize, and, after a slow start, there were a large number of visitors. On the SciBar’s big rockets stall, over 70 rockets were fired at the moon, and we were able to publicize the SciBar to many local people who did not know about us. Below are a couple of photos from the day. Thanks to all SciBarians (and others) who supported the stall.

Lions Fair 1

Rocket launched!

Posted in 2017, out_&_about

8th May 2017 – Human Leucocyte Antigen (HLA) System

Andy Canterbury is the business development manager for MC Diagnostics, a small company based in St Asaph, North Wales and they have developed a DNA microarray platform for medical diagnostic testing; the primary application being HLA typing. Andrew has an MSc in Immunology and started worked in the NHS as a clinical scientist, introducing DNA HLA typing into routine use. He then moved into the commercial world as a R&D scientist before progressing towards more business focused roles.

For your body to combat an infection, it requires a mechanism to distinguish what should be there ‘self’ and what is an invader ‘non-self’. This role is fulfilled by proteins on the cell surface of white blood cells, called Human Leukocyte Antigens (HLA). These molecules can present a major barrier to successful transplantation but by closely matching a patient and donor HLA, the risk of organ rejection is greatly reduced. The methods for HLA typing have developed over the years and today DNA based typing is routinely performed.

HLA-microarray

This image shows their technology. The black dots are a micro array printed in the bottom of a test well. Company software interprets the unique pattern of the dots to provide the HLA result.

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3rd April 2017 – Genes Regulating Ageing

Genes Regulating Ageing and the Quest for Immortality

Dr. Joao Pedro de Magalhaes, Institute of Ageing and Chronic Disease, University of Liverpool.

Ageing-and-immortaly2Hundreds of genes are now known to regulate ageing and have been shown to increase longevity by up to 10-fold in animal models. Drugs mimicking the longevity effects of these genes are now being developed. Studies of species with exceptional longevity (like bowhead whales) or disease resistance (like naked mole rats) may help to improve human health and prevent diseases.

This talk was first presented to Kirkby SciBar 16th August, 2016 and the above information is courtesy their flyer.

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Welcome to the Knutsford SciBar Website

This blog shows all our events, both future and past.

Our next meeting will be on Monday 4th December 2017 at our usual venue, when Dr Jamie Ellingford will talk about DNA in Medicine. You can see the details here.

Please note that the start time will be 19.30 until announced otherwise. The entrance fee is £2 (free to students and under 21s).

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