£1.00 – £1.90
Boulder clay from Yorkshire, UK from the Pleistocene period, shows random sized various clasts within a glacial clay matrix. Formed through various glacial or ice sheet processes, these sedimentary rocks are available in various sizes.
Boulder clay (also known as till), in the terms of geology is in reference to clay which is formed various ground moraine material from glacier and ice sheet activity, past of present, as such, sorting of such material is practically absent and orientation of clasts is completely random. As the name suggest, boulders can be found in this variation of clay, however, the size of samples we supply do not exhibit this. It is produced from the attrition (scraping) of the top layers of rock which come in to contact with the ice in a glacier or ice sheet, this attrition of the top most layers of rock is what produces the fine silt clay, and anything of any size in the path of the glacier or ice sheet (form pebbles to boulders) become incorporated into said clay. These specimens exhibit small pebble sized clasts when viewed closely, they are date to the Pleistocene period, some 2,588,000 to 11,700 years ago and come from Yorkshire, UK. Rock specimens are available in various sizes and will come in a card tray with an information label.