Tarn reveals evidence of its history back to glacial times (25 March 2010)

Postgraduate researchers from Exeter University spent two days at locations around Urswick Tarn assisting Mark Grosvenor, seen below third from the left, to take cores from the sediment deposits around the tarn.  Mark is working towards a Ph.D. degree in the School of Geography and Urswick Tarn is a key location for his research.  After spending one day taking exploratory cores at a number of sites, two were selected for the extraction of cores for laboratory analysis.  The team can be seen preparing to take core  sections, each half a metre in length, at The Landing fen south below the ruin of the former stone hen house which, with tongue in cheek from former times, has been known locally as 'the boathouse'.   The site produced a stratigraphic succession passing initially through the peat layers and then down through the carbonate deposits of the marl bench, all the way to the till deposits left by the last glacier that travelled down the Furness peninsula from the valleys around Coniston. The till deposit marked the end of the soft paste-like carbonate sequence which is of greatest relevance to this particular research programme.  The core segments were carefully wrapped and protected for their journey to Exeter where analysis will be primarily based on pollens and oxygen isotopes, but will also make use of radiocarbon dating techniques.  When laboratory results from these cores become known to those involved in other research programmes focussed on chironomid (non-biting midge) skeletal remains it is probable that further coring will be required around the same location.  Each of the sub-species of chironomids are extremely selective about the environment in which they live (i.e. they are stenotopic) and skeletal remains of their cast larval skins, especially their head capsules, leave an accurate record of the temperature prevailing at the stratigraphic level at which they are found in a core sequence.

The second locality where core segments were collected for laboratory analysis was the lawn of the village chapel at the north end of the tarn.  The depth of coring at both localities exceeded 8 metres.

The Exeter research programme will involve further terrestrial coring plus the taking of core samples from below the tarn itself.  The latter will necessitate the use of a specialist coring device known as a Mackereth corer, trials with which were carried out on the tarn at the beginning of March.  The next coring is expected to take place in early summer.  A particular problem hidden beneath the waters of the tarn are the deep haematite sediments transported to the tarn from the many mines around Lindal in Furness in the nineteenth century via a specially dug underground drain.  These must be penetrated before the carbonate sediments can be accessed and must therefore be shallower than the maximum coring depth of the Mackereth.

The deposits below Urswick Tarn and its surroundings hold many stories yet to be discovered, the Exeter programme being but one line of investigation.  Conservation of the remaining sites that have not already been compromised by the-hand-of-man is extremely important. 

This programme of research by the School of Geography at Exeter University is part funded by the Sir John Fisher Foundation.

News on earlier phases of this work may be seen by clicking the following dates:  15 December 2009 and 23 July 2009.  The latter shows a smaller version of a Mackereth corer than that which will be used for future coring on the tarn.

Winter memories (10 January 2010)

The current extended spell of cold weather, which has retained snow cover for much longer than is normally the case in modern times, invokes memories of when the exception was a winter which did not include such a period of snow cover and freezing conditions.  Half a century ago it was usual for the smaller ponds around Urswick to freeze over and become safe enough for skating.  But even then it was exceptional for Urswick Tarn to become covered in ice with sufficient strength to  allow the tarn to be crossed on foot.  The above photograph, taken in the winter of 1947, shows the youth of the then village community, some wearing skates -  which many villagers possessed in those times - out on the tarn during one of those very cold winters.

John Bolton recorded that in the winter of 1852-53, several days and nights of hard frost covered the tarn with clear smooth ice.  Together with joiner and skate grinder, George Kirkby, he prepared to take soundings of the depth of the tarn through the ice.  He reported that George had said, "Ye'll find it a queer spot, for I assuer ye thair is weed in Girt Ossick Tarn beath thicker an' langer than t' biggest tree i' Bardsea Park".  It is an indication of the lack of knowledge about the depth of the tarn and the influence of local folk lore at that time that Mr. Bolton equipped himself with 2000 feet of fine strong whipcord  before venturing onto the tarn with a brace fitted with a 1.125 inch diameter bit.  Using a weighted line in this way, lowered through a matrix of holes drilled through the ice across the entire tarn, he was disappointed to find that the deepest sounding was only 41 feet.

Ref: Bolton, J. 1869. Geological Fragments of Furness and Cartmel 1869.  Republished in 1978 by Michael Moon with a Gazetteer, Contents List and Dramatis Personae provided by the late Harry Kellett of Dalton.  ISBN. 09-04131-20-3.

The problem with geese (15 October 2009)

In the above photograph, over 370 geese are grazing on land immediately adjacent to Urswick Tarn.  The flock consists almost entirely of Greylags [Anser anser] and on some days the flock is even larger.  Most mornings they fly in after a night spent elsewhere and draw attention to their dramatic flight formations with their loud and distinctive voices and the noise of air turbulence produced by their powerful wings.
But they present a number of significant problems.  Geese feed on land, typically grazing on grass and harvest stubble, but spend a large amount of time on water where, unseen by the observer, they defecate, adding nutrients which cause algal growth, reduced water quality and all of the knock-on ecological consequences which result from an excess of nutrients in the water.  Further, they are responsible for damaging the reed beds which are an important habitat on which many other species depend.  Sadly, in the case of Urswick Tarn, this adds to the large amount of damage done by humans over recent decades.  Additionally, they are responsible for erosion along the land boundary with the tarn and the resulting destruction of waterside flora.  In some locations these attributes of wild geese necessitate control measures being implemented, but these are far from easy to implement.
Those with an inclination to observe the geese flocks may be interested to try and identify male-male pairings since it has been established [Reference 1] that homosociality is common, particularly amongst greylag geese, but only involving ganders. 

Ref 1: Kotrschall, K., Hemetsberger, J., Weiss, B.M.  2006.  Making the most of a bad thing: homosociality in male greylag geese; a paper within: Homosexual Behaviour in Animals - An
evolutionary perspective.   ISBN-13 978-0-521-86446-6

To the memory of John Bolton (3 August 2009)

"The tarn is almost completely encircled by a thick belt of reeds (Phragmites), flags (Iris), bullrushes (Cyperaceae), &c., except at the 'coot-stones,' where is an open space ten or fifteen yards in width, and the north-west portions of the tarn for about half an acre is flagged on the surface of the water with broad green circular leaves, and the beautiful pearl white cups of the water lily (Nymphea alba). ...."

So wrote John Bolton, geologist, of Little Urswick and later Swarthmoor, who became a national authority and whose circle of colleagues included the most eminent of geological professionals.  He died at Sedgwick Cottage, Swarthmoor in 1873, his home there having been named after his great friend Professor Adam Sedgwick of Cambridge.  Adam Sedgwick originated from Dent and his considerable contribution to the science of geology is marked by the Sedgwick Museum of Earth Sciences, part of the University of Cambridge.

The above photograph is a close-up of a very small area of White water-lily, one of only two now to be found around Urswick Tarn.  If permitted by good management and recognition of the significant opportunity for remediation that now exists around the tarn, the days may return when its character can again be described as was recorded above by this distinguished former village resident and pupil of Urswick Grammar School.

Ref: Bolton, J. 1869. Geological Fragments of Furness and Cartmel 1869.  Republished in 1978 by Michael Moon with a Gazetteer, Contents List and Dramatis Personae provided by the late Harry Kellett of Dalton.  ISBN. 09-04131-20-3.

Moorhen numbers decline & Coot population at a very low level (25 July 2009)