5.2 Chemical Weathering – Physical Geology - opentextbc.ca
Figure 5.10 A granitic rock containing biotite and amphibole which have been altered near to the rock's surface to limonite, which is a mixture of iron oxide minerals. [SE] A special type of oxidation takes place in areas where the rocks have elevated levels of sulphide minerals, especially pyrite (FeS 2). Pyrite reacts with water and oxygen ...