Economic Geology and Hydrology

Economic geology, scientific discipline concerned with the distribution of mineral deposits, the economic considerations involved in their recovery, and an assessment of the reserves available. Water is one of our most precious natural resources. Without it, there would be no life on earth. Hydrology has evolved as a science in response to the need to understand the complex water system of the earth and help solve water problems. Hydrogeology is the study of groundwater – it is sometimes referred to as geohydrology or groundwater hydrology. Hydrogeology deals with how water gets into the ground (recharge), how it flows in the subsurface (through aquifers) and how groundwater interacts with the surrounding soil and rock (the geology). An aquifer is a body of saturated rock through which water can easily move. Aquifers must be both permeable and porous and include such rock types as sandstone, conglomerate, fractured limestone and unconsolidated sand and gravel. Fractured volcanic rocks such as columnar basalts also make good aquifers. The rubble zones between volcanic flows are generally both porous and permeable and make excellent aquifers. In order for a well to be productive, it must be drilled into an aquifer. Groundwater can become depleted if we use it at a faster rate than it can replenish itself. The replenishment of aquifers by precipitation is called recharging. Depletion of aquifers has increased primarily due to expanding agricultural irrigation. Groundwater can become contaminated when an excessive amount of pesticides and herbicides are sprayed on agricultural fields, septic tanks leak, or landfills are improperly lined or managed and toxic materials seep through the soil into the aquifer. The book has a balanced coverage of conventional techniques of hydrology along with the latest topics, which makes it equally useful to practising engineers. This book is a comprehensive overview of economic geology for the general geologist and anyone else interested in the minerals industry and the global supply of raw materials.