Explain with examples how climate affects weathering
Answers
Weathering occurs one of three ways: through physical processes such as freezing and thawing, because of live organisms whose roots break rocks or through chemical processes that occur when carbon dioxide in the soil and air and mixes with water and specific minerals in rocks to form a weak acid that reduces rocks into silt, soil and sediment.
Chemical weathering typically increases as temperatures rise and rain falls, which means rocks in hot and wet climates experience faster rates of chemical weathering than do rocks in cold, dry climates.
Physical weathering occurs more often in cold climates, because the different minerals within rocks expand and contract at different rates when they are heated and cooled. Repeated heating and cooling cycles eventually cause rocks to fracture. Desert and mountain climates experience a wide range of temperatures from low to high during a day and night, which accounts for the breakdown of rocks known as physical weathering.
Biological weathering occurs when living organisms break up rocks. Tree roots, for example, can fracture rocks in the same way they buckle pavement. Warm, humid climates are most favorable to life. Contrast the rich diversity of life in a rainforest, for example, with the scarcity of life in the dry Sahara or the frigid Antarctic. Consequently, rates of biological weathering are most rapid in warm humid climates like those in tropical regions.
Climate Affects Weathering
Average temperatures, precipitation, wind and sun over the course of a year define a region’s seasonal weather patterns known as climate. Some types of rocks weather more rapidly in humid climates, while dry climates make other rocks more susceptible to attack. Limestone weathers rapidly in areas with wet climates, where rainwater mixed with carbon dioxide in soil or creates a weak acid that dissolves the limestone to form crevices and valleys. Sandstone, by contrast, weathers more rapidly in dry climates, because the quartz in the sandstone is largely invulnerable to chemical weathering but can fall prey to fracturing caused by ice formed when water freezes and expands in cracks in the stone.