Salt Crystal Growth • Definition: Salt crystallization (haloclasty) • Grouped under Physical Weathering(rocks break down under environmental conditions under heat, pressure or ice), but involves some chemical weathering (hydration) • Formation of salt crystals in weathering • Usually occurs in dry and arid conditions like deserts (warm climates)
Salt Crystal Growth • Process: => When saline solutions enter the rocks through cracks and evaporate, salt crystals are then left behind • They expand when the surroundings increase in temperature • Rocks receive the pressure exerted by the salt crystals and they disintegrate • Over time grains of sand can be dislodged or soil can be forced upwards and out.
Salt Crystal Growth • Factors • Climate (Salt Crystal growth works best under arid and hot climates--- strong heating =>higher evaporation rate=> more salt’ll crystallize) • Environment (common among coastlines and sea walls) • Physical Conductivity (poor heat conductivity=> different rates of expansion and contraction=> surface’ll expand more=> more stress/pressure exerted
Salt Crystal Growth • Locations: • Beaches (seawater is blown onto rocks by strong coastal winds, then water evaporates and salt crystallizes) • Arid areas like deserts • Atacama (South America) and Namib (South Africa)
Salt Crystal Growth Landforms formed: • Tafoni (small cave-like features found in granular rock, with smooth concave-like walls) • Honeycomb weathering Resultant processes: • Granular disintegration • Spalling (occurs in porous building materials ; dissolved salts crystallises near the surface of the rock as the water evaporates)