Complex sentence: Large amounts of coarse gravel and boulders carried along underneath the glacier provide the abrasive power to cut trough-like glacial grooves, and finer sediments also in the base of the moving glacier further scour and polish the bedrock surface, forming a glacial pavement.
Split into simpler sentences: Large amounts of coarse gravel and boulders carried along underneath the glacier provide the abrasive power to cut trough-like glacial grooves. Finer sediments also in the base of the moving glacier further scour and polish the bedrock surface, forming a glacial pavement.