Among the largest mistakes in cosmogenic nuclide matchmaking dabei from a bad sampling plan. Because cosmic rays merely infiltrate the top of very few centimetres of a rock, activity of a boulder downslope may lead to big problems during the age measured.
Before trying a rock, geologists has to take detail by detail and mindful data of this landsurface, and match on their own that rock is actually a stable position, haven’t rolled, fallen downslope, started over and over buried and exhumed during periglacial stone bicycle within productive level (usually an issue with tiny big river rocks), and it has not just started covered with considerable amounts of soil, accumulated snow or vegetation.
Signs of subglacial transport
Geologists also must make sure that the rock offers withstood adequate glacial erosion to get rid of any stone that could get previously become subjected inside the Earths surface, and so have actually amassed cosmogenic nuclides.
They would like to taste a rock they are yes provides undergone subglacial transfer. Might thus test stones which happen to be subrounded, faceted, bear striations, or demonstrate some other signs and symptoms of subglacial transportation.