GEO 1111 Lecture Notes - Lecture 14: Spheroidal Weathering, Weathering, Granite Dome

• School: University of Ottawa
• Department: Geology
• Course: GEO 1111
• Professor: Robert Jack Cornett

Document Summary

Weatheri(cid:374)g i(cid:374)(cid:448)ol(cid:448)es the ph(cid:455)si(cid:272)al (cid:271)reakdo(cid:449)(cid:374) a(cid:374)d (cid:272)he(cid:373)i(cid:272)al alteratio(cid:374) of ro(cid:272)k at or (cid:374)ear earth(cid:859)s surfa(cid:272)e. Frost wedging sheeting/unloading biological activity salt crystal growth. Frost wedging: water works its way into cracks in rocks and the freezing enlarges the cracks in the rocks. Lenses of ice grow larger as they attract liquid water from surrounding areas. Large masses of igneous rock are exposed by erosion and glaciation & concentric slabs break loose: an exfoliation dome is formed after continued weathering causes the slabs to separate and spall of. Joints are fractures produced by contraction during the crystallization of magma. Biological activity: pla(cid:374)t roots gro(cid:449) i(cid:374)to fra(cid:272)tures i(cid:374) a ro(cid:272)k, (cid:272)ausi(cid:374)g the (cid:272)ra(cid:272)ks to e(cid:454)pa(cid:374)d, burro(cid:449)i(cid:374)g a(cid:374)i(cid:373)als (cid:271)reak do(cid:449)(cid:374) ro(cid:272)ks (cid:271)(cid:455) (cid:373)o(cid:448)i(cid:374)g fresh (cid:373)aterial to the surfa(cid:272)e, e(cid:374)ha(cid:374)cing physical and chemical weathering. The most important agent is water responsible for transport of ions and molecules involved in chemical processes. Types of chemical weathering dissolution oxidation hydrolysis spheroidal weathering.