This report, has the main aim of critically analysing two sediment samples (coarse sample taken from Clarach/ fine sample taken from Tan-y-Bwlch (6)) to identify any discrimination between their geological characteristics, the main characteristic being grain size, but shape, roundness and surface details are also important, as they can provide information to answer the wider question of what processes have occurred for the lithologies of the 2 sites to have been formed in the way that they have.
To analyse such a wide range of characteristics four methods of analysis were performed, the experiments that were conducted are as follows; dry sieve analysis for both samples, clast roundness analysis for 50 clasts collected at Clarach, …show more content…
Dry sieve analysis was performed on both samples from each site, the pipette method was performed on the fine sample and the laser granulometer method was conducted on the coarse sample, this allowed for a wide range of geological characteristics to be analysed accurately.
Dry Sieve Method:
Dry sieve analysis is a procedure (3) used to assess the gradation of a granular material (McGlinchey, 2005). The dry sieve method is performed to allow for the sorting of the grain sizes from largest to smallest, between 4Φ and -4Φ. This method also allows for the acquisition of a pan fraction from the samples taken from the two sites, which can then be further sorted and analysed more accurately using other methods of grain size separation.
Pipette Method:
The pipette method (4) is a fine grain analysis method which provides a detailed analysis of the finer particle sizes of samples. Therefore, the pipette method is used to analyse the fine sample that was collected from the fieldwork at Tan-y-Bwlch, as it provides a more in-depth analysis of the pan fraction collected by the dry sieve method, and would provide results which can be compared against the rest of the class’ to see if a trend is occurring, which would help to validate the …show more content…
Laser granulometry measures particle size distributions by measuring the angular variation in intensity of light scattered as a laser passes through a dispersed particulate sample. Large particles scatter light at small angles relative to the laser beam and small particles scatter light at large angles. The angular scattering intensity data is then analysed to calculate the size of the particles responsible for creating the scattering pattern, using Mie theory