Weathering and Soils

Weathering

the process of rocks breaking down at or near the earths surface

do rocks always weather uniformly?

no, different rock types and even variations within the same rock can weather at different rates leading to uneven weathering patterns and often called differential weathering

products of mechanical weathering

small fragments of the original rock, essentially ‘debris’ which can include sand, slit, and clay particles

mechanical weathering

the process of breaking down rocks into fragments without changing the chemical composition of the minerals within the rock.

ways weathering occurs?

frost wedging, frost heaving, salt wedging, sheeting

frost wedging

water freezing cracks, pushes rocks apartWater-freezing cracks

frost heaving

the upward or outward movement of the ground surface by the growth of ground ice

salt wedging

salt crystals grow within cracks in rocks, causing them to expand and break apart the rock as the salt water evaporates

sheeting

large igneous rock masses expand and fracture due to pressure release

products of chemical weathering

clay mineral, dissolved ions, quartz

Chemical weathering

process by which minerals rock composition changes due to chemical reactions such as water, air, acids

What are the factors that control (affect) soil formation?

parent material, topography, climate, plants, animals/ other organisms, time

parent material

the type of rock that soil forms from determines its physical and chemical properties

topography

affects the movement of water, air, and nutrients in the landscape.