The iliac crest is the curved superior border of the ilium, the largest of the three bones that merge to form the os coxa, or hip bone. It is located on the superior and lateral edge of the ilium very close to the surface of the skin in the hip region. When a person places their hands on their hips, it is the skin above the iliac crest that they rest their hands on.
1. Weathering is a term which describes the general process by which rocks are broken down at the Earthâs surface into such things as sediments, clays, soils and substances that are dissolved in water. 2. The process of weathering typically begins when the earthâs crust is uplifted by tectonic forces. After the physical breakup and chemical decay of exposed rocks by weathering, the loosened rock fragments and alterations products are carried away through the process of erosion.
Chemical Weathering. Chemical weathering is caused by rain water reacting with the mineral grains in rocks to form new minerals (clays) and soluble salts. These reactions occur particularly when the water is slightly acidic.These chemical processes need water, and occur more rapidly at higher temperature, so warm, damp climates are best.Chemical weathering (especially hydrolysis and oxidation) is the first stage in the production of soils.here are different types of chemical weathering, the most important are: Solution-removal of rock in solution by acidic rainwater. In particular, limestone is weathered by rainwater containing dissolved CO2, (this process is sometimes called carbonation).