hypocentre

 
2012 01 11 Stoke Earthquake

Yesterday Stoke-on-Trent experienced a minor, magnitude 2.4 tremor that we picked up on our seismometer at Keele.

I think that the official location, near Light Oaks, is a bit too far east as it is almost certainly a former coal mining induced event and the main coal measure sequence is further west. It will be interesting to find out where the felt reports come from.

We haven’t had earthquakes in the north of the city since the Smallthorne sequence of 1988-1990.

It is interesting that we have coal mining induced events of this size and nobody turns a hair, however, if it had been shale gas extraction related, the world would be about to end.

Jan 112012
 
Malvern 2

I have been out the last couple of days undertaking fieldwork for a building stones project, but today I was treated to a glimpse of a gem of a little geological section being prepared. Those of us who work in geoconservation talk a lot about geodiversity but this must be the most geodiverse section I have come across. It is a trench, only about 100m long but displays rocks from the Precambrian, Cambrian, Silurian, Carboniferous and Triassic.

The trench runs across the crest of the ‘Malvern Axis’, a major monoclinal fold trending north-south through central England that brings up Precambrian (~677 Ma; Cryogenian) to the surface. The Malvern line separates the two Precambrian terranes of the Midlands Microcraton, Wrekin Terrane to the west and Charnian Terrane to the east, that forms the solid basement of England. These Precambrian igneous rocks are unconformably overlain by Middle Cambrian Malvern Quartzite, and then Upper Silurian (Pridoli) Raglan Mudstone, and Upper Carboniferous (Moscovian) Halesowen Fm. This sequence was folded and thrust during the Variscan Orogeny at the end of the Carboniferous into the north-south Malvern Axis. Extension during the Triassic produced normal faulting along the Malvern Line and deposition of Middle Triassic (Anisian) Bromsgrove Sandstone to the east in the Worcester Graben. All this is being exposed in just one 100m trench, albeit somewhat tectonically shortened.

Standing on the axis, this is the view to the east. In the trench, the light coloured material in the foreground is Precambrian Malvern Complex, succeeded by grey/green and grey Carboniferous, red Silurian muds and Triassic sands towards the car.

To the west, the white is Cambrian followed by Carboniferous and Silurian on the other side of the axis. Note that many of the lithological identifications are still tentative.

The section is still in the process of being created and is on private land, but should be stunning when finished.

 
Rock3660021

Photographically 2011 was a poor year for me, most of my better shots were taken on a single photoshoot weekend in Liverpool. After Rock365 in 2010 I was a bit jaded photographically and even when I went out I tended not to take the 5D with me. I experimented with a few iPhone pictures and the instagram app which was interesting but they are not good enough to post here. With Rock366 already on the go and a Baltic cruise scheduled for the summer, 2012 already looks like being a better year. However, from the scant pickings of 2011 here are my best five.

New Year's fireworks display, Funchal, Madeira

Dinas Bran, Llangollen

Stained glass window in Anglican Cathedral, Liverpool

Port of Liverpool Building

Altar piece, Catholic Cathedral, Liverpool

 
Buttermere Formation Olistostrome

I must be mad. In 2010 I misguidedly decided to photograph a rock on each day of the year and project Rock365 was born. And 365 days and photographs later I managed it. It took me a whole year to recover.

So, how to better Rock365? The answer is to wait for a leap year and launch Rock366, the project to photograph a rock on each day of 2012. Now, this is going to present a few challenges like I’m going on a cruise this summer to celebrate the big five-oh, but I’ve managed similar things before.

For the past fortnight I have been out walking and recuperating from the autumn semester’s teaching in the Lake District of northwest England. The first images therefore are from here.

Day 1 : The Buttermere and Ennerdale Granophyre

This the the Buttermere and Ennerdale Granophyre – a granophyric microgranite from the shores of Buttermere in the Lake District. It was intruded as a laccolith, just over 1 kilometre thick, in the Late Ordovician.

Day 2 : Buttermere Formation Olistostrome

The Lower Ordovician (Tremadocian / Floian [Arenig]) Buttermere Formation is an olistostrome deposit at least 1.5 kilometres thick. The unit, of which this sample is fairly coarse, was believed to have been emplaced as a single massive slumping event in the late Floian. This breccia was found as a loose block in Yewthwaite Comb on the western flank of Catbells in the Newlands Valley.

Day 3 : Sphalerite in vein quartz

This is a sample collected on the previous day from the mine spoil heaps at Yewthwaite Comb. The Lake District is quite heavily mineralised with Ordovician copper mineralisation along east-west faults and Carboniferous lead-zinc veins trending north-south. The fireplace in the Swinside Inn in the Newlands Valley has large samples of galena and sphalerite rich vein rock built into the surround. I found the sphalerite zinc-ore sample here in the mine dumps on the walk back from the pub.

As a bonus, I have a few more rock photographs taken on my stroll up Catbells.

Buttermere Formation, Catbells Summit

Here is the more typical finer-grained Buttermere Formation on the summit of CatBells, displaying some slump folding.

Quartz vein, Yewthwaite Comb, Cumbria

Back at the mining area, here is some vein quartz and some brecciated wall rock.

If you are interested in following Rock366 the daily posts will be on my posterous blog so as not to clog up this site [RSS feed].

The photographs will also be on my Rock366 flickr set [RSS feed]. The 2010 Rock365 set is here.

I shall also endeavour, like last time, to georeference the rocks using google maps.


View Rock366 in a larger map

 
Park Hall Kidderminster Fm

These are some troubling times in British Geoconservation with several geoconservation sites around the country coming under attack from various sources.

First, let’s start close to home at Park Hall, Staffordshire.


[image: Kidderminster Fm, Park Hall, Staffordshire. source: Ian G. Stimpson]

Park Hall is a SSSI (Site of Special Scientific Interest) and National Nature Reserve (NNR) for its geology (Lower Triassic Kidderminster Formation [formerly known as the Bunter Pebble Beds]) exposed in former aggregate quarries. Situated on the edge of Stoke-on-Trent its Visitor Centre hosted visits from school children to study the local geology and biology. The GeoconservationUK Education Project [Earth Science On-Site] uses former aggregates sites like Park Hall to develop examples of high quality Earth Science field teaching activities for schools. Education for primary school students in Stoke-on-Trent is some of the worst in the country. It is hard to get schools to get the children outdoors and studying their natural environment but Park Hall Visitor Centre was a success. Instead of the centre having to chase the schools, the schools contacted the centre. Many had repeat visits booked annually in their diaries. Then on the night of November 6 thoughtless vandals broke into the centre, set a fire and razed it to the ground. The conflagration took with it tens of thousands of pounds worth of education materials for the school children of Stoke-on-Trent and the wider area.


[image: Demolition work at the Park Hall vistor centre after the fire. source: John Reynolds]

Other display material was lost including examples of local Carboniferous Coal Measure plant fossils had been lost in the blaze. It is the shear mindless thuggery of it all that saddens me. They also targeted a saddlery and several horses could easily have died.

Attempts are now under way to try to persuade Stoke-on-Trent City Council to rebuild the centre and have geology teaching as a showcase part of the new centre. However, in these straitened times it is always possible that this will prove impossible.

Another Earth Science On-Site location on the Kidderminster Formation has also been targeted by vandals. Barr Beacon, Walsall has had its war memorial roof stripped of copper by metal thieves. Whilst not affecting the geology of the site, including the Staffordshire Tixall Stone used for the memorial steps, this is still sickening.


[image: Barr Beacon War Memorial targeted by metal thieves : source Express and Star]

From England to Scotland where they have been having their own problems. On the beautiful Isle of Skye, perhaps more famous for its igneous rocks than its sedimentary ones, there are exposures of fossiliferous Jurassic rocks that have yielded the only Scottish dinosaur remains. Bearreraig Bay, north of Portree, is another SSSI, where any collecting is limited to that for scientific use, and that by permission only. Those convicted for either damaging a SSSI or collecting without permission can be subject to an unlimited fine. The section appears to have been attacked with a crowbar with several tonnes of rock moved in an attempt to extract fossils and dinosaur footprints may also have been removed from Valtos.


[image: Damaged fossils at Bearreraig Bay. source: Scottish Natural Heritage / BBC]

It would appear that the recession is driving a minority to increasing levels of theft, be it metals or fossil material. Another sign of the recession is the loss of UNESCO Geopark status by the Lochaber Geopark. UNESCO require that a permanent project officer be employed. It has been increasingly difficult to obtain funds for geoconservation funding. Where I am in Staffordshire all regular sources of funding have dried up (or appropriated by the national government), so it is little surprise that the volunteers in Scotland have struggled to raise the money for a salaried member of staff. This is the real Big Society, volunteers working for the good of the community and it is failing through lack of proper funding and support.

The Lochaber Geopark includes Glen Roy with its famous “parallel roads”, the shorelines of glacially dammed lakes. Charles Darwin visited Glen Roy in 1838 and described it as “far the most remarkable area I ever examined.” Darwin, however, was a much better geologist than a glaciologist, and ascribed the roads to marine effects.

The general mood in British geoconservation is on a downer. Funding has largely dried up and the government’s new planning laws appear to be ignoring any special consideration of local geodiversity or biodiversity sites. And, to top it all, the government has issued a new White Paper, the first such on the natural environment in over twenty years, called Natural Choice. It fails to mention ‘geology, geoconservation or geodiversity’ anywhere in the document. Here is their definition of ‘natural environment’

“In this White Paper, we have given ‘natural environment’ a broad meaning [sic]. wildlife, rivers and streams, lakes and seas, urban green space and open countryside, forests and farmed land. It includes the fundamentals of human survival: our food, fuel, air and water, together with the natural systems that cycle our water, clean out pollutants, produce healthy soil, protect us from floods and regulate our climate. And it embraces our landscapes and our natural heritage, the many types of contact we have with nature in both town and country.”

The definition simply isn’t broad enough. Perhaps they should have used Wikipedia

“The natural environment encompasses all living and non-living things”.

The lack of mention of geodiversity means that councils are already cutting back on their geoconservation work as they say that it isn’t now covered by government thinking.

At the moment those of us who work in geoconservation are feeling unloved, underfunded and under attack. Dark days indeed.

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