Boulder tracing and geological mapping of the bedrockSurface till sampling
Surface till sampling can be done in different ways, with a shovel, or with a handheld drill. When sampling with a shovel, a hole is dug in the ground until one reaches unweathered till - the C-horizon, which is sampled (figure 4). The hole is usually 0.5 - 1 metres deep. The sample is collected in a sample bag, after which the hole is filled in again with the dug up material. When sampling with a handheld drill, a small hole is drilled in the till (approx. 5 cm in diameter), down to the desired depth, after which the drilling is stopped and the sample is collected in a bag. The sampler, located farther down on the drill head, captures the sample at the depth where the drilling was stopped. Surface moraine sampling generally causes no disturbance to the environment.
Fig 4. Schematic diagram illustrating a section of typical Swedish soil, the podsol. Unweathered till are sampled.