GY 111 Lecture Notes D Haywick 2008 09 1 GY 111 Lecture Note Series Economic Geology Lecture Goals A Economic Minerals resources versus reserves B Mineral formation C Mineral extraction A Economic Minerals By now you have been introduced to the minerals that you are going to be responsible for in the lab component of GY 111L I hope that you have also begun to recognize the importance of some of these materials If not consider this table that I extracted directly from the GY 111L Lab manual Table 1 5 Economic uses of some minerals Mineral Economic Use aluminum ore bauxite Portland cement chalk antacids calcite vitamins antacid garden lime dolomite chalcopyrite copper ore lead ore galena garnet gemstones jewelry sand paper sheetrock plaster cosmetics gypsum lubricants pencil lead graphite halite table salt jewelry mineral peridot olivine abrasives girl s best friends diamond sulfur pharmaceuticals asphalt plastics dental applications steel flux fluorite clay pottery tile Kaopectate cosmetics kaolinite iron ore hematite iron ore limonite magnetite iron ore malachite jewelry copper ore quartz electronic applications sphalerite zinc ore lubricant talcum powder talc It lists the main uses of some of the GY 111L minerals in the collection Truth be told there are many other uses of geological materials that are have not listed here and of course many other minerals that are important to our society that are also not listed here Definition time Any mineral that has economic potential i e it makes someone money is defined as an economic mineral All of the minerals listed in table 1 5 are economic minerals Additional economic minerals include the native elements Gold Silver and Platinum virtually every sulfide known e g Molybdenite MoS cinnabar HgS etc GY 111 Lecture Notes 1 D Haywick 2008 09 2 2 3 4 5 Figure 1 Examples of important economic minerals 1 gold 2 silver 3 cinnabar 4 molybdenite 5 uraninite All images from http webmineral com specimens picshow php id 1478 most of the oxides e g uraninite UO2 and lots of the minerals comprising the remaining mineral classes You will not see these other economic minerals in GY 111 GY111L but if you are a geology major you will see them in GY 302 Can t wait The minerals that are underlined are pictured above Right now you are probably thinking that on minerals factor in as economicallyimportant geological materials As it turns out neither gold nor diamonds nor platinum are as economically important to the US economy as limestone sand or gravel crushed rock These rocks are considered important building materials and are used so extensively in the United States that they dwarf the economic significance of the economic minerals however that s not necessarily the case in other countries In Canada and Australia where there are much lower populations and therefore less demand for building materials and much more extensive economic mineral deposits gold diamond GY 111 Lecture Notes D Haywick 2008 09 3 Gold mining data USGS Commodities information for 2007 and sulfide mineral mining are major components of their economies In fact Canada1 and Australia are considered to be primary resource economies which is why in 2008 they are escaping the economic turndown that is really hurting the USA At least for now If the US economy does not improve soon there will be a big decrease in the demand for economic minerals so even primary resource economies will start to contract It s time to now consider two other terms Resources are defined as any substance vital or necessary for a society Obviously the term mineral resources refers to those minerals that we require Building resources are materials that we need for construction like sand gravel etc energy resources are fossil fuels that we need for energy and water resources are supplies of drinking water For your information geologists are responsible for locating and extracting all of these substances If it sounds like you owe you very existence to geology you are absolutely correct In fact there is a saying Any resource that is not grown or raised is ultimately geological in nature and when you consider that you have to grow plants in soil and raise animals on plants that grow on soil even food is somewhat geological in origin soil is a geological material too Perhaps now you can appreciate why geologists are in such high demand even despite the poor economy and why should you ever pass a geologists you should give them a hug The last definition that is required at this point in the lecture is reserves as in mineral reserves This is the total amount of an economic mineral that has been found and that is likely to be found in the future For example we can estimate the likely amount of gold in the United States based upon the known amounts that have been found in all of the active mines in the country and in the new plays currently worked see table at the start of this page Reserves are not necessarily the absolute total of a mineral that exists just how much we ve found to date In some cases e g uranium aluminum we will probably 1 This is especially true for Canada if you throw in the other major economic geology materials like oil natural gas and fresh water GY 111 Lecture Notes D Haywick 2008 09 4 never run out of reserves In most cases however e g gold platinum we will run out someday B Mineral Formation Sadly in this course it is not possible to spare the time to go over how all economic minerals form We have to choose one or two In this country much of the economic wealth in geology is courtesy of base metal sulfides These include the GY 111L minerals sphalerite chalcopyrite galena and other minerals like molybdenite cinnabar and covellite CuS The list is a long one that you need not concern yourself about here For this lecture we ll stick with copper minerals Copper bearing sulfides like chalcopyrite and covellite are mostly formed through the action of hot water Deposits like this are called hydrothermal and form in areas where either groundwater2 comes in contact with hot magma deep below the surface of the Earth or a particularly wet magma dewaters near the surface of the Earth see cartoon to the left from www answersingenesis org Under these conditions liquid water can heat up to 400 or 500 C however it remains a fluid owing to high confining pressure 1000 s of m below the surface Water this hot becomes extremely aggressive and is capable of striping normally insoluble materials from the host rocks This