Knowledge Geological Comments and techniques and skills a. Rock is disaggregated Distinguish between the Candidates should be by weathering and processes of weathering able to describe and erosion into particles and erosion and evaluate explain the following of various sizes and their significance in the weathering processes; dissolved materials sedimentary freeze-thaw that are transported characteristics and the (mechanical), and deposited to form geological history of carbonation (chemical) new sediments. sedimentary rock. and the action of plant roots (biological). Weathering takes place in situ, erosion involves transport/removal of weathered products from site of production. Candidates should be able to describe and explain the following erosional processes with respect to rivers, the sea, ice and wind: Abrasion, attrition, b. The grain size, shape Interpret: Candidates should be able hydraulic action, and sorting of the the distance of to describe the grain size solution. resultant sediment is transport from the characteristics of influenced by the shape and sorting of sediments from energy of the sediment photomicrographs, transporting medium the energy level of hand specimens and and the depositional the environment of photographs. environment [screes, deposition from rivers, shallow/deep sediment grain size. See Practical Guidance seas, wind- formed Sheet 4. dunes]. See Practical Guidance Sheet 5.
Knowledge and Geological techniques and skills Comments a. Rock is disaggregated by weathering and erosion into particles of various sizes and dissolved materials that are transported and deposited to form new sediments. Distinguish between the processes of weathering and erosion and evaluate their significance in the sedimentary characteristics and the geological history of sedimentary rock. Candidates should be able to describe and explain the following weathering processes; freeze-thaw (mechanical), carbonation (chemical) and the action of plant roots (biological). Weathering takes place in situ, erosion involves transport/removal of weathered products from site of production. Candidates should be able to describe and explain the following erosional processes with respect to rivers, the sea, ice and wind: Abrasion, attrition, hydraulic action, solution. b. The grain size, shape and sorting of the resultant sediment is influenced by the energy of the transporting medium and the depositional environment [screes, rivers, shallow/deep seas, wind- formed dunes]. Interpret: the distance of transport from the shape and sorting of sediment the energy level of the environment of deposition from sediment grain size. Candidates should be able to describe the grain size characteristics of sediments from photomicrographs, hand specimens and photographs. See Practical Guidance Sheet 4. See Practical Guidance Sheet 5.