Earth Sciences 1070A/B Lecture Notes - Lecture 4: Ripple Marks, Mica, Biogenic Substance

• School: Western University
• Department: Earth Sciences
• Course: Earth Sciences 1070A/B
• Professor: Natalie Pietrzak- Renaud

Document Summary

Broad term that encompasses a variety of chemical, physical, and biological processes that a(cid:272)t to (cid:271)reak do(cid:449)(cid:374) ro(cid:272)ks i(cid:374) pla(cid:272)e (cid:374)ear or at earth"s surfa(cid:272)e. After broken down, rock products are transported and redeposited by wind, water, or ice, and are then categorized as sediment. Usually categorized as mechanical or chemical, dominance depends on climate. Rock compositions, topography, and climate determine what sediments form, rate of weathering, and how sediments are transported. Physical breakdown or disintegration of rocks without changing composition. Requires application of physical stress or force such as water. In cold climates, water freezes and expands rock to create fractures, then thaws and cracks contract. Process is called frost-wedging, more prominent in mountainous regions also disintegrates roads in canada. Frost wedging loosens rock fragments that tumble down slope and form large piles called talus slopes at base of steep outcrops.