Saturday, 10 November 2012

Angular whinstone layer above the Cleveland dyke

I made this excavation into the Cleveland dyke exposure at Stainsby beck Thornaby on tees today, i was surprised to find a layer of angular whinstone, averaging 350mm thick about 1 metre above the dyke, separated by a stoneless alluvial clay deposit, the same clay deposit also covers the whinstone bed.
 How this layer of whinstone got to sit a metre above the stoneless alluvial layer then be buried under the same type of stoneless deposit is beyond my understanding at the moment.

 In the above image the orange tool marks the top of the angular whinstone bed- layer ?
 In the above image the Dyke outcrop can be seen just above the water line, then the stoneless alluvial layer, then the angular whinstone deposit.
 The image above shows another piece of rounded whinstone, with pieces of decomposing whinstone around it.
 The rest of the images show some cleaned up examples of the whinstone in the deposit, there all magnetic, though for some reason the rounded pieces seem far more magnetic, than the angular whinstone.