EPSC 201 Lecture Notes - Lecture 16: Bulgarian Lev, Evaporite, Ripple Marks
Document Summary
There are two types of weather; physical and chemical. In the desert, there is predominantly physical weathering. The chemical reactions need water and heat to occur. The breakdown of limestone and marble requires acid. Acid can be found naturally from the breakdown of organic material, such as pine needles. Carbon dioxide is generated from the breakdown of limestone, which easily leaves. The products of the breakdown are either gaseous, or soluble in water, which makes the breakdown very easy. Potassium feldspar when exposed to acid breaks down into clay and quartz, along with potassium ion. If the structure hasn"t broken down after weathering, there will be lots of clay and quartz present, because that what granite breaks down into. Quartz is resistant to weathering, and this is why we see nice sandy beaches of quartz. Water is a polar molecule, and helps dissolve ions through its dipoles. The water molecules point their negative oxygen towards positive ions, such as potassium.