EAPS 10200 Lecture Notes - Lecture 6: Graded Bedding, Depositional Environment, Lithification

• School: Purdue University
• Department: Earth Atmos Planetary Sci
• Course: EAPS 10200
• Professor: Professor Balloti

Document Summary

Sedimentary rocks: sedimentary rocks form through a complex cycle of weathering, erosion, transport, deposition, and lithification. Igneous rocks are weathered by wind and/or water and are eroded (transported) downslope by streams and rivers. They are then deposited in river valleys, lakes and oceans. Over time they accumulate into thick layers and become compacted and cemented. Only 5% of surface rocks are sedimentary but they are distributed over 75% of the surface: lithification is the process of weathered and eroded sediments becoming competent rock. First is sedimentation and then cementation: sediments come in a variety of grain size and type. In any case as the sediments are delivered to a calm lake or ocean they settle to the bottom of the water. Over time more sediments are deposited on top and the pressure forces grains into contact. These minerals will precipitate out of the water onto the sediment grains essentially cementing them together.