By the end of this chapter, students should be able to:
- Describe how a resource is different from a resource.
- Compare the pros and cons of extracting and using and conventional and unconventional sources.
- Describe how are formed and extracted.
- Understand how society uses resources.
This text has previously discussed geology’s pioneers, such as scientists James Hutton and Charles Lyell, but the first real “geologists” were the hominids who picked up stones and began the stone age. Maybe stones were first used as curiosity pieces, maybe as weapons, but ultimately, they were used as tools. This was the Paleolithic , the beginning of geologic study, and it dates back 2.6 million years to east Africa.
In modern times, geologic knowledge is important for locating economically valuable materials for society’s use. In fact, all things we use come from only three sources: they are farmed, hunted or fished, or . At the turn of the twentieth century, speculation was rampant that food supplies would not keep pace with world demand, suggesting the need to develop artificial fertilizers. Sources of fertilizer ingredients are: nitrogen is processed from the , using the Haber process for the manufacture of ammonia from atmospheric nitrogen and hydrogen; potassium comes from the , such as lakes or ocean evaporation; and phosphorus is from the , such as minerals like apatite from phosphorite rock, which is found in Florida, North Carolina, Idaho, Utah, and around the world. Thus, without and processing of natural materials, modern civilization would not exist. Indeed, geologists are essential in this process.
is defined as extracting valuable materials from the Earth for society’s use. Usually, these include solid materials such as gold, iron, , diamond, sand, and gravel, but materials can also include fluid resources such as and . Modern has a long relationship with modern society. The oldest dates back 40,000 years to the Lion Cavern in Swaziland where there is evidence of concentrated digging into the Earth for hematite, an important iron used as red dye. Resources extracted by are generally considered to be .
16.1.1 Renewable versus Nonrenewable Resources
Resources generally come in two major categories: and . resources can be reused over and over or their availability replicated over a short human life span; resources cannot.
resources are materials present in our environment that can be exploited and replenished. Some common energy sources are linked with green energy sources because they are associated with relatively small or easily remediated environmental impact. For example, solar energy comes from within the Sun, which radiates electromagnetic energy. This energy reaches the Earth constantly and consistently and should continue to do so for about five billion more years. Wind energy, also related to solar energy, is maybe the oldest energy and is used to sail ships and power windmills. Both solar and wind-generated energy are variable on Earth’s surface. These limitations are because we can use energy storing devices, such as batteries or electricity exchanges between producing sites. The Earth’s heat, known as geothermal energy, can be viable anywhere that geologists drill deeply enough. In practice, geothermal energy is more useful where heat flow is great, such as zones or regions with a thinner . Hydroelectric dams provide energy by allowing water to fall through the dam under gravity, which activates turbines that produce the energy. Ocean tides are also a reliable energy source. All of these resources provide energy that powers society. Other resources are plant and animal matter, which are used for food, clothing, and other necessities, but are being researched as possible energy sources.
resources cannot be replenished at a sustainable rate. They are finite within human time frames. Many resources come from planetary, , or long-term biologic processes and include materials such as gold, lead, copper, diamonds, , sand, , , and . Most resources include specific concentrated listed on the periodic table; some are compounds of those . For example, if society needs iron (Fe) sources, then an exploration geologist will search for iron-rich deposits that can be economically extracted. resources may be abandoned when other materials become cheaper or serve a better purpose. For example, is abundantly available in England and other nations, but because and are available at a lower cost and lower environmental impact, use has decreased. Economic competition among resources is shifting use away from in many developed countries.
Earth’s materials include the periodic table . However, it is rare that these are concentrated to the point where it is profitable to extract and process the material into usable products. Any place where a valuable material is concentrated is a geologic and geochemical . A body of material from which one or more valuable substances can be mined at a profit, is called an deposit. Typically, the term is used for only metal-bearing , but it can be applied to valuable resource concentrations such as , building stones, and other nonmetal deposits, even . If a metal-bearing resource is not profitable to , it is referred to as a deposit. The term is more common than the term for non-metal-bearing materials.
It is implicit that the technology to is available, economic conditions are suitable, and political, social and environmental considerations are satisfied in order to classify a deposit as . Depending on the substance, it can be concentrated in a narrow vein or distributed over a large area as a low-concentration . Some materials are directly from bodies of water (e.g. sylvite for potassium; water through desalination) and the (e.g. nitrogen for fertilizers). These differences lead to various methods of , and differences in terminology depending on the certainty. mineral resource is used for an indication of that is potentially extractable, and the term reserve is used for a well defined (proven), profitable amount of extractable .
16.1.3 Mining Techniques
The style is determined by technology, social license, and economics. It is in the best interest of the company extracting the resources to do so in a cost-effective way. Fluid resources, such as and gas, are extracted by drilling wells and pumping. Over the years, drilling has evolved into a complex discipline in which directional drilling can produce multiple bifurcations and curves originating from a single drill collar at the surface. Using geophysical tools like imaging, geologists can pinpoint resources and extract efficiently.
Solid resources are extracted by two principal methods of which there are many variants. is used to remove material from the outermost part of the Earth. is used to target shallow, broadly disseminated resources.
requires careful study of the body through surface mapping and drilling exploratory cores. The pit is progressively deepened through additional cuts to extract the . Typically, the pit’s walls are as steep as can be safely managed. Once the pit is deepened, widening the top is very expensive. A steep wall is thus an engineering balance between efficient and profitable (from the company’s point of view) and ( from a safety p0int of view) so that there is less waste to remove. The waste is called non-valuable rock or overburden and moving it is costly. Occasionally, do occur, such as the very large in the Kennecott Bingham Canyon , Utah, in 2013. These events are costly and dangerous. The job of engineering geologists is to carefully monitor the mine; when company management heeds their warnings, there is ample time and action to avoid or prepare for any slide.
and are techniques that are used to resources that cover large areas, especially layered resources, such as . In this method, an entire mountaintop or rock layer is removed to access the below. ’s environmental impacts are usually much greater due to the large surface footprint that’s disturbed.
is a method often used to higher-, more localized, or very concentrated resources. For one example, geologists some underground by introducing chemical agents, which the target . Then, they bring the to the surface where extracts the material. But more often, a shaft tunnel or a large network of these shafts and tunnels is dug to access the material. The decision to underground or from Earth’s surface is dictated by the deposit’s concentration, depth, geometry, land-use policies, economics, surrounding rock strength, and physical access to the . For example, to use techniques for deeper deposits might require removing too much material, or the necessary method may be too dangerous or impractical, or removing the entire overburden may be too expensive, or the footprint would be too large. These factors may prevent geologists from materials and cause a project to be underground. The method and its feasibility depends on the commodity’s price and the cost of the technology needed to remove it and deliver it to market. Thus, and the towns that support them come and go as the commodity price varies. And, conversely, technological advances and market demands may reopen and revive ghost towns.
16.1.4 Concentrating and Refining
All occur mixed with less desirable components called . The process of physically separating from ore bearing is called . Separating a desired from a host by chemical means, including heating, is called . Finally, taking a metal such as copper and removing other trace metals such as gold or silver is done through the process. Typically, is done one of three ways: 1. Materials can either be mechanically separated and processed based on the ’s unique physical properties, such as recovering gold based on its high density. 2. Materials can be heated to chemically separate desired components, such as crude into . 3. Materials can be smelted, in which controlled chemical reactions unbind metals from the they are contained in, such as when copper is taken out of chalcopyrite (CuFeS2). , , , and processes require enormous energy. Continual advances in metallurgy- and mining-practice strive to develop ever more energy efficient and environmentally benign processes and practices.
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16.2 Fossil Fuels
are extractable sources of stored energy that were created by ancient ecosystems. The that typically fall under this category are , , , and . These resources were originally formed via photosynthesis by living organisms such as plants, phytoplankton, algae, and cyanobacteria. This energy is actually solar energy, since the sun’s ancient energy was converted by ancient organisms into tissues that preserved the chemical energy within the . Of course, as the energy is used, just like photosynthetic respiration that occurs today, carbon enters the as CO2, causing consequences (see chapter 15). Today humanity uses for most of the world’s energy.
Converting solar energy by living organisms into hydrocarbon is a complex process. As organisms die, they decompose slowly, usually due to being buried rapidly, and the chemical energy stored within the organisms’ tissues is buried within surrounding geologic materials. All contain carbon that was produced in an ancient environment. In environments rich with organic matter such as swamps, coral , and planktonic blooms, there is a higher potential for to accumulate. Indeed, there is some evidence that over geologic time, organic hydrocarbon material was highly produced globally. Lack of oxygen and moderate temperatures in the environment seem to help preserve these organic substances. Also, the heat and pressure applied to organic material after it is buried contribute to transforming it into higher quality materials, such as brown to anthracite and to gas. Heat and pressure can also cause mobile materials to migrate to conditions suitable for extraction.
16.2.1 Oil and Gas
Petroleum is principally derived from organic-rich shallow sedimentary deposits where the remains of micro-organisms like plankton accumulated in fine grained . ’s liquid component is called , and its gas component is called , which is mostly made up of methane (CH4). As rocks such as , , or lithify, increasing pressure and cause the and gas to be squeezed out and migrate from the to a different rock unit higher in the rock column. Similar to the discussion of good in chapter 11, if that rock is a , , or other porous and permeable rock, and involved in a suitable or structural trapping process, then that rock can act as an and gas .
A is a combination of a subsurface geologic structure, a porous and permeable rock, and an impervious layer that helps block and gas from moving further, which concentrates it for humans to extract later. A develops due to many different geologic situations. Examples include an or domal structure, an impermeable salt , or a bounded block, which is porous rock next to nonporous rock. The different have one thing in common: they pool fluid into a configuration in which extracting it is more likely to be profitable. or gas in outside of a renders it less viable to extract.
is a branch of geology that studies sedimentary both horizontally and vertically and is devoted to understanding how sea level changes create organic-rich shallow muds, , and sands in areas that are close to each other. For example, environments may have beaches, , , and deposits, all next to each other. Beach sand, lagoonal and muds, and coral reef layers accumulate into that include —good rocks— next to , next to , both of which are potential . As sea level either rises or falls, the shoreline’s location changes, and the sand, mud, and reef locations shift with it (see the figure). This places oil and gas producing rocks, such as mudstones and limestones next to oil and gas reservoirs, such as sandstones and some limestones. Understanding how the lithology and the facies/stratigraphic relationships interplay is very important in finding new petroleum resources. Using sequence stratigraphy as a model allows geologists to predict favorable locations of the source rock and .
16.2.2 Tar Sands
Conventional and gas, which is pumped from a , is not the only way to obtain hydrocarbons. There are a few fuel sources known as unconventional sources. However, they are becoming more important as conventional sources become scarce. Tar sands, or , are that contain products that are highly , like tar, and thus cannot be drilled and pumped out of the ground readily like conventional . This unconventional is bitumen, which can be pumped as a fluid only at very low recovery rates and only when heated or mixed with solvents. So, using steam and solvent injections or directly tar sands to process later are ways to extract the tar from the sands. Alberta, Canada is known to have the largest reserves in the world. Note: as with , an energy resource becomes uneconomic if the total extraction and processing costs exceed the extracted material’s sales revenue. Environmental costs may also contribute to a resource becoming uneconomic.
16.2.3 Oil Shale
, or , is a fine-grained that has significant or quantities locked tightly in the . has high but very low and is a common . To extract the directly from the , the material has to be and heated, which, like with tar sands, is expensive and typically has a negative environmental impact.
Another process used to extract the and gas from and other unconventional tight resources is called , better known as . In this method, high-pressure water, sand grains, and added chemicals are injected and pumped underground. Under high pressure, this creates and holds open in the rocks, which help release the hard-to-access mostly fluids. is more useful in tighter sediments, especially shale, which has a high porosity to store the hydrocarbons but low to allow transmission of the hydrocarbons. Fracking has become controversial because its methods contaminate and induce activity. This has created much controversy between public concerns, political concerns, and energy value.
comes from fossilized swamps, though some older deposits that predate plants are presumed to come from algal buildups. is chiefly carbon, hydrogen, nitrogen, sulfur, and oxygen, with minor amounts of other . As plant material is incorporated into , heat and pressure cause several changes that concentrate the fixed carbon, which is the ’s combustible portion. So, the more heat and pressure that undergoes, the greater is its carbon concentration and fuel value and the more desirable is the .
This is the general sequence of a swamp progressing through the various stages of and becoming more concentrated in carbon: Swamp => Peat => Lignite => Sub-bituminous => Bituminous => Anthracite => Graphite. As swamp materials collect on the swamp floor and are buried under accumulating materials, they first turn to peat.
Peat itself is an economic fuel in some locations like the British Isles and Scandinavia. As occurs, peat turns to lignite. With increasing heat and pressure, lignite turns to sub-bituminous , bituminous , and then, in a process like , anthracite. Anthracite is the highest and most desirable since it provides the highest energy output. With even more heat and pressure driving out all the and leaving pure carbon, anthracite can become graphite.
Humans have used for at least 6,000 years, mainly as a fuel source. resources in Wales are often cited as a primary reason for Britain’s rise, and later, for the United States’ rise during the Industrial Revolution. According to the US Energy Information Administration, US production has decreased due to competing energy sources’ cheaper prices and due to society recognizing its negative environmental impacts, including increased very fine-grained particulate matter as an air pollutant, greenhouse gases, acid rain, and heavy metal pollution. Seen from this perspective, the industry as a source of energy is unlikely to revive.
As the world transitions away from including , and manufacturing seeks strong, flexible, and lighter materials than steel including carbon fiber for many applications, current research is exploring as a source of this carbon.
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16.3 Mineral Resources
resources, while principally , are generally placed in two main categories: , which contain metals, and , which contain other useful materials. Most has been traditionally focused on extracting . Human society has advanced significantly because we’ve developed the knowledge and technologies to yield metal from the Earth. This knowledge has allowed humans to build the machines, buildings, and monetary systems that dominate our world today. Locating and recovering these metals has been a key facet of geologic study since its inception. Every across the periodic table has specific applications in human civilization. is the source of many of these .
16.3.1 Types of Metallic Mineral Deposits
The various ways in which and their associated concentrate to form deposits are too complex and numerous to fully review in this text. However, entire careers are built around them. In the following section, we describe some of the more common deposit types along with their associated elemental concentrations and world class occurrences.
When a magmatic body crystallizes and differentiates (see chapter 4), it can cause certain and to concentrate. Layered intrusions, typically to , can host deposits that contain copper, nickel, platinum, palladium, rhodium, and chromium. The Stillwater Complex in Montana is an example of economic quantities of layered intrusion. Associated deposit types can contain chromium or titanium-vanadium. The largest magmatic deposits in the world are the chromite deposits in the Bushveld Igneous Complex in South Africa. These rocks have an areal extent larger than the state of Utah. The chromite occurs in layers, which resemble sedimentary layers, except these layers occur within a crystallizing .
Water and other that are not incorporated into crystals when a crystallizes can become concentrated around the crystallizing ’s margins. Ions in these hot fluids are very mobile and can form exceptionally large crystals. Once crystallized, these large crystal masses are then called . They form from fluids that are expelled from the solidifying when nearly the entire body has crystallized. In addition to that are predominant in the main mass, such as , , and , bodies may also contain very large crystals of unusual that contain rare like beryllium, lithium, tantalum, niobium, and tin, as well as like gold. Such are of these metals.
An unusual magmatic process is a pipe, which is a that transports from within the to the surface. Diamonds, which are formed at great temperatures and pressures of depth, are transported by a pipe to locations where they can be . The process that created these rocks is no longer common on Earth. Most known deposits are from the .
Fluids rising from crystallizing magmatic bodies or that are heated by the cause many geochemical reactions that form various deposits. The most active process today produces (VMS) deposits, which form from chimney activity near all over the world. They commonly contain copper, zinc, lead, gold, and silver when found at the surface. Evidence from around 7000 BC in a known as the Chalcolithic shows copper was among the earliest metals smelted by humans as means of obtaining higher temperatures were developed. The largest of these VMS deposits occur in rocks. The Jerome deposit in central Arizona is a good example.
Another deposit type that draws on -heated water is a deposit. This is not to be confused with the texture, although the name is derived from the that is nearly always present in the rocks associated with a deposit. Several types of deposits exist, such as copper, molybdenum, and tin. These deposits contain low- disseminated closely associated with and rocks that are present over a very large area. deposits are typically the largest on Earth. One of the largest, richest, and possibly best studied in the world is Utah’s Kennecott Bingham Canyon Mine. It’s an , which, for over 100 years, has produced several including copper, gold, molybdenum, and silver. Underground replacement deposits produce lead, zinc, gold, silver, and copper. In the ’s past, the open pit predominately produced copper and gold from chalcopyrite and bornite. Gold only occurs in minor quantities in the copper-bearing , but because the Kennecott Bingham Canyon Mine produces on such a large scale, it is one of the largest gold in the US. In the future, this may produce more copper and molybdenum (molybdenite) from deeper .
Most copper deposits owe their high metal content, and hence, their economic value to processes called which occurs when the deposit is uplifted, eroded, and exposed to . This process occurred millions of years after the initial intrusion and expulsion ends. When the deposit’s upper pyrite-rich portion is exposed to rain, the pyrite in the oxidizing zone creates an extremely acid condition that dissolves copper out of copper , such as chalcopyrite, and converts the chalcopyrite to iron , such as hematite or goethite. The copper are carried downward in water until they arrive at the table and an environment where the primary copper are converted into secondary higher-copper content . Chalcopyrite (35% Cu) is converted to bornite (63% Cu), and ultimately, chalcocite (80% Cu). Without this enriched zone, which is two to five times higher in copper content than the main deposit, most copper deposits would not be economic to .
If or other calcareous sedimentary rocks are near the magmatic body, then another type of deposit called a deposit forms. These rocks form as -derived, highly saline metalliferous fluids react with rocks to create calcium-magnesium- like , , and garnet, as well as high- iron, copper, zinc , and gold. Intrusions that are genetically related to the intrusion that made the Kennecott Bingham Canyon deposit have also produced copper-gold skarns, which were by the early European settlers in Utah. When iron and/or deposits undergo , the commonly increases, which makes separating the from the desired or much easier.
deposits consist of low concentrations of microscopic gold as and disseminated atoms in pyrite crystals. These are formed via low- reactions, generally in the realm of , that occur in certain rock types, namely muddy and limey . This alteration is generally far removed from a source, but can be found in rocks situated with a high . The Mercur deposit in Utah’s Oquirrh Mountains was this type’s earliest locally deposit. There, almost a million ounces of gold was recovered between 1890 and 1917. In the 1960s, a metallurgical process using cyanide was developed for these low- types. These deposits are also called deposits because the disseminated deposit near Carlin, Nevada, is where the new technology was first applied and where the first definitive scientific studies were conducted. Gold was introduced into these deposits by fluids that reacted with silty calcareous rocks, removing , creating additional , and adding silica and gold-bearing pyrite in the space between grains. The Betze-Post mine and the Gold Quarry mine on the Carlin Trend are two of the largest disseminated gold deposits in Nevada. Similar deposits, but not as large, have been found in China, Iran, and Macedonia.
Non-magmatic Geochemical Processes
Geochemical processes that occur at or near the surface without ’s aid also concentrate metals, but to a lesser degree than processes. One of the main reactions is , short for reduction/ chemistry, which has to do with the amount of available oxygen in a . Places where oxygen is plentiful, as in the today, are considered oxidizing environments, while oxygen-poor places are considered reducing environments. Uranium deposits are an example of where the metal. Uranium is soluble in oxidizing environments and precipitates as uraninite when encountering reducing conditions. Many of the deposits across the Colorado Plateau, such as in Moab, Utah, were formed by this method.
reactions are also responsible for creating (BIFs), which are interbedded layers of iron —hematite and magnetite, , and . These deposits formed early in the Earth’s history as the was becoming oxygenated. Cycles of oxygenating iron-rich waters initiated of the iron . Because BIFs are generally in age, happening at the event of atmospheric oxygenation, they are only found in some of the older exposed rocks in the United States, such as in Michigan’s upper peninsula and northeast Minnesota.
Deep, saline, (trapped in spaces) within may be highly metalliferous. When expelled outward and upward as compacted, these fluids formed lead and zinc deposits in by replacing or filling open spaces, such as caves and , and in by filling spaces. The most famous are called deposits. Also known as deposits, they are large deposits of galena and sphalerite lead and zinc that form from hot fluids ranging from 100°C to 200°C (212°F to 392°F). Although they are named for occurring along the Mississippi River Valley in the US, they are found worldwide.
deposits occurring in , , and marls are enormous, and their contained resources are comparable to copper deposits. These deposits were most likely formed diagenetically by fluids in highly permeable rocks. Well-known examples are the Kupferschiefer in Europe, which has an areal coverage of >500,000 Km2, (310,685.596mi) and the Zambian Copper Belt in Africa.
and deposits that are exposed at the surface experience deep and intense , which can form surficial deposits. , an aluminum , is preserved in topography and laterites, which are formed in wet tropical environments. containing aluminum concentrate , such as , and ferromagnesian in and rocks, undergo processes that concentrate the metals. rocks that undergo form nickel-rich , and when the magnetite and hematite in undergo , it forms goethite, a friable that is easily for its iron content.
Surficial Physical Processes
At the Earth’s surface, and moving water can cause hydraulic , which forces high-density to concentrate. When these minerals are concentrated in , , and beaches, they are called deposits, and occur in modern sands and ancient lithified rocks. gold, platinum, , ilmenite, rutile, magnetite, diamonds, and other gemstones can be found in . Humans have mimicked this natural process to recover gold manually by gold panning and by mechanized means such as dredging.
16.3.2 Environmental Impacts of Metallic Mineral Mining
’s primary impact comes from the itself, including disturbing the land surface, covering landscapes with tailings impoundments, and increasing by accelerating . In addition, many metal deposits contain pyrite, an uneconomic , that when placed on waste dumps, generates (ARD) during . In oxygenated water, such as pyrite react and undergo complex reactions to release metal ions and hydrogen ions, which lowers pH to highly acidic levels. and processing of materials typically increase the surface area to volume ratio in the material, causing chemical reactions to occur even faster than would occur naturally. If not managed properly, these reactions lead to acidic and plumes that carry toxic metals. In where is a waste rock or where like or dolomite are present, their acid neutralizing potential helps reduce . Although this is a natural process too, it is very important to isolate dumps and tailings from oxygenated water, both to prevent the from dissolving and subsequently percolating the -rich water into waterways. Industry has taken great strides to prevent contamination in recent decades, but earlier projects are still causing problems with local ecosystems.
16.3.3 Nonmetallic Mineral Deposits
While receiving much less attention, resources, also known as industrial , are just as vital to ancient and modern society as . The most basic is building stone. , , , , and are common building stones and have been quarried for centuries. Even today, building stones from roof tiles to countertops are very popular. Especially pure is ground up, processed, and reformed as plaster, cement, and concrete. Some resources are not specific; nearly any rock or can be used. This is generally called aggregate, which is used in concrete, roads, and foundations. Gravel is one of the more common aggregates.
deposits form in restricted basins where water evaporates faster than it , such as the Great Salt Lake in Utah, or the Dead Sea, which borders Israel and Jordan. As the waters evaporate, soluble are concentrated and become supersaturated, at which point they from the now highly-saline waters. If these conditions persist for long stretches, thick rock salt, rock , and other deposits accumulate (see chapter 5).
, such as , are used in our food as common table salt. Salt was a vitally important food preservative and economic resource before refrigeration was developed. While still used in food, is now mainly as a chemical agent, water softener, or road de-icer. is a common used as a building material; it is the main component in dry wall. It is also used as a fertilizer. Other include sylvite—potassium chloride, and bischofite—magnesium chloride, both of which are used in agriculture, medicine, food processing, and other applications. Potash, a group of highly soluble potassium-bearing , is used as a fertilizer. In hyper-arid locations, even more rare and complex , like borax, trona, ulexite, and hanksite are . They can be found in places such as Searles Dry Lake and Death Valley, California, and in the Green River Formation’s ancient deposits in Utah and Wyoming.
Phosphorus is an essential that occurs in the apatite, which is found in trace amounts in common rocks. Phosphorite rock, which is formed in sedimentary environments in the ocean, contains abundant apatite and is to make fertilizer. Without phosphorus, life as we know it is not possible. Phosphorous is an important component of bone and DNA. Bone and guano are natural sources of phosphorus.
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Energy and resources are vital to modern society, and it is the role of the geologist to locate these resources for human benefit. As environmental concerns have become more prominent, the value of the geologist has not decreased, as they are still vital in locating the deposits and identifying the least methods of extraction.
Energy resources are general grouped as being or . Geologists can aid in locating the best places to exploit resources (e.g. locating a dam), but are commonly tasked with finding . resources are also grouped in two categories: and . have a wide variety of processes that concentrate them to economic levels, and are usually via surface or underground methods.
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Figure 16.1: A Mode 1 Oldowan tool used for chopping. José-Manuel Benito Álvarez. 2007. Public domain. https://commons.wikimedia.org/wiki/File:Canto_tallado_2-Guelmim-Es_Semara.jpg
Figure 16.2: Map of world mining areas. KVDP. 2009. Public domain. https://commons.wikimedia.org/wiki/File:Simplified_world_mining_map_1.png
Figure 16.3: Hoover Dam provides hydroelectric energy and stores water for southern Nevada. Ubergirl. 2012. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:Hoover_Dam,_Colorado_River.JPG
Figure 16.4: Natural, octahedral shape of diamond. USGS. 2003. Public domain. https://commons.wikimedia.org/wiki/File:Rough_diamond.jpg
Figure 16.5: Banded-iron formations are an important ore of iron (Fe). Wilson44691. 2008. Public domain. https://commons.wikimedia.org/wiki/File:MichiganBIF.jpg
Figure 16.6: Diagram illustrating the relative abundance of proven reserves, inferred reserves, resources, and undiscovered resources. Kindred Grey. 2022. CC BY 4.0.
Figure 16.7: McKelvey diagram showing different definitions for different degrees of concentration and understanding of mineral deposits. USGS. 1980. Public domain. https://commons.wikimedia.org/wiki/File:McKelveyDiagram.jpg
Figure 16.8: Bingham Canyon Mine, Utah. Doc Searls. 2016. CC BY 2.0. https://commons.wikimedia.org/wiki/File:Bingham_Canyon_mine_2016.jpg
Figure 16.9: A surface coal mine in Wyoming. Bureau of Land Management. Unknown date. Public domain. https://www.usgs.gov/news/science-snippet/earthword-thermal-maturity
Figure 16.10: Underground mining in Estonia of oil shale. Kaupo Kikkas. 2011. CC BY-SA 4.0. https://commons.wikimedia.org/wiki/File:VKG_Ojamaa_kaevandus.jpg
Figure 16.11: A phosphate smelting operation in Alabama, 1942. Alfred T. Palmer. 1942. Public domain. https://commons.wikimedia.org/wiki/File:TVA_phosphate_smelting_furnace.jpg
Figure 16.12: Coal power plant in Helper, Utah. David Jolley. 2007. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:Castle_Gate_Power_Plant,_Utah_2007.jpg
Figure 16.13: Modern coral reefs and other highly-productive shallow marine environments are thought to be the sources of most petroleum resources. Toby Hudson. 2010. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:Coral_Outcrop_Flynn_Reef.jpg
Figure 16.14: World oil reserves in 2013. GunnMap; generated with settings from Emilfaro and A5b. 2014. CC BY-SA 1.0. https://commons.wikimedia.org/wiki/File:Oil_Reserves.png
Figure 16.15: Examples of different forms of hydrocarbon traps: in the core region of anticlines. MagentaGreen. 2014. CC BY-SA 4.0. https://commons.wikimedia.org/wiki/File:Anticlinal_Oil_trap.png
Figure 16.16: The rising sea levels of transgressions create onlapping sediments, regressions create offlapping. Woudloper. 2009. CC BY-SA 1.0. https://commons.wikimedia.org/wiki/File:Offlap_%26_onlap_EN.svg
Figure 16.18: Global production of oil shale, 1880-2010. USGS. 2011. Public domain. https://commons.wikimedia.org/wiki/File:Production_of_oil_shale.png
Figure 16.20: USGS diagram of different coal rankings. USGS. 2009. Public domain. https://commons.wikimedia.org/wiki/File:Coal_Rank_USGS.png
Figure 16.21: Peat (also known as turf) consists of partially decayed organic matter. David Stanley. 2019. CC BY 2.0. https://commons.m.wikimedia.org/wiki/File:Peat_(49302157252).jpg
Figure 16.22: Anthracite coal, the highest grade of coal. USGS. 2007. Public domain. https://commons.wikimedia.org/wiki/File:Coal_anthracite.jpg
Figure 16.23: Gold-bearing quartz vein from California. James St. John. 2014. CC BY 2.0. https://commons.wikimedia.org/wiki/File:Mother_Lode_Gold_OreHarvard_mine_quartz-gold_vein.jpg
Figure 16.24: Layered intrusion of dark chromium-bearing minerals, Bushveld Complex, South Africa. kevinzim / Kevin Walsh. 2006. CC BY 2.0. https://commons.wikimedia.org/wiki/File:Chromitite_Bushveld_South_Africa.jpg
Figure 16.25: This pegmatite contains lithium-rich green elbaite (a tourmaline) and purple lepidolite (a mica). Parent Géry. 2011. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:Elba%C3%AFte_et_mica_(Br%C3%A9sil)_1.JPG
Figure 16.26: Schematic diagram of a kimberlite pipe. Asbestos. 2005. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:VolcanicPipe.jpg
Figure 16.27: The complex chemistry around mid-ocean ridges. NOAA. 2011. Public domain. https://commons.wikimedia.org/wiki/File:Deep_Sea_Vent_Chemistry_Diagram.svg
Figure 16.28: The Morenci porphyry is oxidized toward its top (as seen as red rocks in the wall of the mine), creating supergene enrichment. Stephanie Salisbury. 2012. CC BY 2.0. https://commons.wikimedia.org/wiki/File:Morenci_Mine_2012.jpg
Figure 16.29: Garnet-augite skarn from Italy. Siim Sepp. 2012. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:00031_6_cm_grossular_calcite_augite_skarn.jpg
Figure 16.30: In this rock, a pyrite cube has dissolved (as seen with the negative “corner” impression in the rock), leaving behind small specks of gold. Matt Affolter (QFL247). 2009. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:GoldinPyriteDrainage_acide.JPG
Figure 16.31: Underground uranium mine near Moab, Utah. Matt Affolter. 2010. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:UraniumMineUtah.JPG
Figure 16.32: Map of Mississippi-Valley type ore deposits. Kbh3rd. 2010. CC BY 3.0. https://commons.wikimedia.org/wiki/File:MV-Type_and_clastic_sediment-hosted_lead-zinc_deposits.svg
Figure 16.33: A sample of bauxite. Werner Schellmann. 1965. CC BY-SA 2.5. https://commons.wikimedia.org/wiki/File:Bauxite_with_unweathered_rock_core._C_021.jpg
Figure 16.34: Lithified heavy mineral sand (dark layers) from a beach deposit in India. Photograph taken by Mark A. Wilson (Department of Geology, The College of Wooster). 2008. Public domain. https://commons.wikimedia.org/wiki/File:HeavyMineralsBeachSand.jpg
Figure 16.35: Acid mine drainage in the Rio Tinto, Spain. Carol Stoker, NASA. 2002. Public domain. https://commons.wikimedia.org/wiki/File:Rio_tinto_river_CarolStoker_NASA_Ames_Research_Center.jpg
Figure 16.36: Carrara marble quarry in Italy, source to famous sculptures like Michelangelo’s David. Michele~commonswiki. 2006. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:Carrara_Marble_quarry.jpg
Figure 16.37: Salt-covered plain known as the Bonneville Salt Flats, Utah. Michael Pätzold. 2008. CC BY-SA 4.0. https://commons.wikimedia.org/wiki/File:Bonneville_salt_flats_pilot_peak.jpg
Figure 16.38: Hanksite, Na22K(SO4)9(CO3)2Cl, one of the few minerals that is considered a carbonate and a sulfate. Matt Affolter(QFL247). 2009. CC BY-SA 3.0.
Figure 16.39: Apatite from Mexico. Robert M. Lavinsky. Before March 2010. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:Apatite-(CaF)-280343.jpg
A resource which is replaced on human time scales.
A resource that is not able to be replaced on human time scales.
Energy resources (typically hydrocarbons) derived from ancient chemical energy preserved in the geologic record. Includes coal, oil, and natural gas.
A liquid fossil fuel derived from shallow marine rocks (also known as crude oil).
Minerals with a luster similar to metal and contain metals, including valuable elements like lead, zinc, copper, tin, etc.
A natural substance that is typically solid, has a crystalline structure, and is typically formed by inorganic processes. Minerals are the building blocks of most rocks.
Minerals that have a luster that is not similar to metal. Divided into subtypes based on the way light reflects (or doesn't), including glassy/vitreous, greasy, pearly, dull, etc.
A unit of the geologic time scale; smaller than an era, larger than an epoch. We are currently in the Quaternary period.
Place where material is extracted from the Earth for human use.
The gases that are part of the Earth, which are mainly nitrogen and oxygen.
The water part of the Earth, as a solid, liquid, or gas.
The outermost physical layer of the Earth, made of the entire crust and upper mantle. It is brittle and broken into a series of plates, and these plates move in various ways (relative to one another), causing the features of the theory of plate tectonics.
Former swamp-derived (plant) material that is part of the rock record.
A dark liquid fossil fuel derived from petroleum.
Gaseous fossil fuel derived from petroleum, mostly made of methane.
Valuable material in the Earth, typically used for metallic mineral resources.
A process inside stars where smaller atoms combine and form larger atoms.
Amount of movement during a faulting event.
Place where lava is erupted at the surface.
The outermost chemical layer of the Earth, defined by its low density and higher concentrations of lighter elements. The crust has two types: continental, which is the thick, more ductile, and lowest density, and oceanic, which is higher density, more brittle, and thinner.
The theory that the outer layer of the Earth (the lithosphere) is broken in several plates, and these plates move relative to one another, causing the major topographic features of Earth (e.g. mountains, oceans) and most earthquakes and volcanoes.
A metamorphosed limestone.
A group of all atoms with a specific number of protons, having specific, universal, and unique properties.
Data which is out of the ordinary and does not fit previous trends.
Water that is below the surface.
Items that are found within Earth that are valuable and limited. Examples include coal, water, and gold.
Energy that radiates from fault movement via earthquakes.
Mining that occurs near the Earth's surface.
Large surface mine with opening carved into the ground.
Large surface mine with opening carved into the ground.
Any downhill movement of material, caused by gravity.
Slope angle where shear forces and normal forces are equal.
General term for sudden material falling (sliding) down a slope due to gravity.
Mining that occurs as entire layers of ore and gangue are removed.
Mining that occurs within tunnels and shafts inside the Earth.
A qualitative measure of the amount of metamorphism that has occurred or the amount of a resource present in an ore.
The process in which solids (like minerals) are disassociated and the ionic components are dispersed in a liquid (usually water).
The act of taking a solid and dissolving it into a liquid. This commonly occurs with salts and other minerals in water.
The act of a solid coming out of solution, typically resulting from a drop in temperature or a decrease of the dissolving material.
Material found around ore which is less valuable and needs to be removed in order to obtain ore.
A mechanical process which takes ore and separates it from gangue material.
A process which chemically separates desired element(s) from ore minerals.
Removing trace elements from desired elements.
Deposit of heavy ores in stream or beach sediments.
Energy resources (typically hydrocarbons) derived from ancient chemical energy preserved in the geologic record. Includes coal, oil, and natural gas.
Any evidence of ancient life.
Long term averages and variations within the conditions of the atmosphere.
A topographic high found away from the beach in deeper water, but still on the continental shelf. Typically, these are formed in tropical areas by organisms such as corals.
Places that are under ocean water at all times.
Pieces of rock that have been weathered and possibly eroded.
A very fine-grained rock with very thin layering (fissile).
A rock made of primarily mud, i.e. particles smaller than sand (≤0.064 mm).
A chemical or biochemical rock made of mainly calcite.
The measure of the vibrational (kinetic) energy of a substance.
A rock that contains material which can be turned into petroleum resources. Organic-rich muds form good source rocks.
A rock or sediment that has good permeability and porosity, and allows water to move easily, making it possible to get water for human use.
A rock primarily made of sand.
The study of rock layers and their relationships to each other within a specific area.
Rocks which allow petroleum resources to collect or move.
A geologic circumstance (such as a fold, fault, change in lithology, etc.) which allows petroleum resources to collect.
Downward-facing fold, that has older rock in its core.
A rock up-warping of symmetrical anticlines.
Planar feature where two blocks of bedrock move past each other via earthquakes.
Discernible layers of rock, typically from a sedimentary rock.
The study of changes in the rock record caused by changing sea level over time.
A specific set of features that are tied together in an interpretive group. Facies can be based on mineralogy, biologic factors, fossils, rock types, etc.
Mineral group in which the carbonate ion, CO3-2, is the building block. This can also refer to the rocks that are made from these minerals, namely limestone and dolomite (dolostone).
The part of the coastline which is directly related to water-land interaction, specifically the tidal zone and the range of wave base.
Interior body of ocean water, at least partially cut off from the main ocean water.
Shore area between low tide and storm wave base. Upper part is dominated by fair weather wave base, lower part is dominated by storm wave base.
The part of the coastline which is below any wave base action.
Sands or sandstones that contain high-viscosity petroleum.
The resistance of a fluid to flow, where a high value means a fluid which does not like to flow (like toothpaste), and a low value means a fluid which flows easily (like water).
Oil which is found in low-permeability, high-porosity rocks such as shale.
Rocks that are formed by sedimentary processes, including sediments lithifying and precipitation from solution.
Amount of empty space within a rock or sediment, including space between grains, fractures, or voids.
The ability for a fluid to travel between pores, or, how connected the pores are within a rock or sediment.
A process of injecting pressurized fluids into the ground to aid in hydrocarbon migration.
A break within a rock that has no relative movement between the sides. Caused by cooling, pressure release, tectonic forces, etc.
Depositional environments that are on land.
An extensive, distinct, and mapped set of geologic layers.
The process of turning sediment into sedimentary rock, including deposition, compaction, and cementation.
Rocks and minerals that change within the Earth are called metamorphic, changed by heat and pressure. Metamorphism is the name of the process.
Components of magma which are dissolved until it reaches the surface, where they expand. Examples include water and carbon dioxide. Volatiles also cause flux melting in the mantle, causing volcanism.
An igneous rock with extremely low silica composition, being made of almost all olivine and pyroxene. Ultramafic rocks contain very low amount of silica and are common in the mantle. Primary ultramafic rocks are komatiite (extrusive) and peridotite (intrusive).
Can refer to a volcanic rock with lower silica composition, or the minerals that make up those rocks, namely olivine, pyroxene, amphibole, and biotite. Mafic rocks are darker in color and contain more minerals that are dark in color, but can contain some plagioclase feldspar. Primary mafic rocks are basalt (extrusive) and gabbro (intrusive).
A reservoir of magma below a volcano.
Liquid rock within the Earth.
A rock (or texture within a rock) with unusually-large crystals, minerals with rare trace element concentrations, and/or unusual minerals, typically forming in veins as the last dredges of magma crystallize.
Rocks that are formed from liquid rock, i.e. from volcanic processes.
SiO2. Transparent, but can be any color imaginable with impurities. No cleavage, hard, and commonly forms equant masses. Perfect crystals are hexagonal prisms topped with pyramidal shapes. One of the most common minerals, and is found in many different geologic settings, including the dominant component of sand on the surface of Earth. Structure is a three-dimensional network of silica tetrahedra, connected as much as possible to each other.
Consisting of three end members: potassium feldspar (K-spar, KAlSi3O8), plagioclase with calcium (CaAl2Si2O8, called anorthite), and plagioclase with sodium (NaAlSi3O8, called albite). Commonly blocky, with two cleavages at ~90°. Plagioclase is typically more dull white and gray, and K-spar is more vibrant white, orange, or red.
X1A2-3Z4O10(OH, F)2, where commonly X=K, Na, Ca; A=Al, Mg, Fe; Z=Si, Al. Has two more-common occurrences, light-colored (translucent and pearly tan) muscovite, and dark-colored biotite. Has one strong cleavage, and is typically seen as sheets, in stacks or "books." Common in many igneous and metamorphic rocks. Structure is two-dimensional sheets of silica tetrahedra in a hexagonal network.
Minerals made from just a single element, bonded to itself. Examples include gold, silver, copper, and diamond, which is a native version of carbon.
An ultramafic rock from deep volcanic vents that can contain diamonds.
Pipe that connects the magma chamber to the volcanic vent.
Middle chemical layer of the Earth, made of mainly iron and magnesium silicates. It is generally denser than the crust (except for older oceanic crust) and less dense than the core.
Eon defined as the time between 4 billion years ago to 2.5 billion years ago. Most of the oldest rocks on Earth, including large portions of the continents, formed at this time.
The largest span of time recognized by geologists, larger than an era. We are currently in the Phanerozoic eon. Rocks of a specific eon are called eonotherms.
The average change in temperature that is experienced as material moves into the Earth. Near the surface, this rate is about 25°C/km.
Metamorphism which occurs with hot fluids going within rocks, altering and changing the rocks.
Metallic mineral deposit which forms near mid-ocean ridges.
Mineral chimneys that form at hydrothermal vents.
A divergent boundary within an oceanic plate, where new lithosphere and crust is created as the two plates spread apart. Mid-ocean ridge and spreading center are synonyms.
A term for the collective time before the Phanerozoic (pre-541 million years ago), including the Hadean, Archean, and Proterozoic. Known for a lack of easy-to-find fossils.
Large metallic mineral deposit that forms near magma bodies like plutons. Commonly contains copper, lead, zinc, molybdenum, and gold.
An igneous rock with two distinctive crystal sizes.
Arrangement of minerals within a rock.
A volcanic rock with medium silica composition, equally rich in felsic minerals (feldspar) and mafic minerals (amphibole, biotite, pyroxene). Intermediate rocks are grey in color and contain somewhat equal amounts of minerals that are light and dark in color. Primary intermediate rocks are andesite (extrusive) and diorite (intrusive).
Can refer to a volcanic rock with higher silica composition, or the minerals that make up those rocks, namely quartz, feldspar, and muscovite mica. Felsic rocks are lighter in color and contain more minerals that are light in color. Primary felsic rocks are rhyolite (extrusive) and granite (intrusive).
Igneous rock cooling, and thus forming, inside of the Earth, i.e. under the surface.
Breaking down rocks into small pieces by chemical or mechanical means.
Oxidation that occurs in sulfide deposits which can concentrate valuable elements like copper.
Certain metallic elements (like iron) take in oxygen, causing reactions like rust.
Minerals in which ions are bonded to oxygen, such as hematite (Fe2O3).
Carbonate rock that reacts with hot magmatic fluids, creating concentrated ore deposits, which include copper, iron, zinc, and gold.
Mineral group in which the silica tetrahedra, SiO4-4, is the building block.
XY(Al,Si)2O6, in which X typically equals Na, Ca, Mg, or Fe and Y typically equals Mg, Fe, or Al. Typically black to dark green, blocky, with two cleavages at ~90°. Common in mafic igneous rocks and some metamorphic rocks. Structure is a single chain of silica tetrahedra.
A group of chain silicate minerals that form needlelike or prismatic crystals. Can be many colors but the most common form, hornblende, is dark brown to black. Has oblique cleavages at 54° and 126°. Common in many igneous rocks and some metamorphic rocks.
Minerals bonded via a sulfur (S-2) atom.
The average diameter of a grain of sediment, ranging from small, also known as fine-grained (e.g. clay, silt) to large, also known as coarse-grained (e.g. boulder).
Low grade, broad deposits of microscopic gold found in sedimentary rocks with diagenetic alteration.
A piece of a rock that is caught up inside of another rock.
Changes in sedimentary rocks due to increased (but low when compared to metamorphism) temperatures and pressures. This can include deposition of new minerals (e.g. limestone converting to dolomite) or dissolution of existing minerals.
Empty space in a geologic material, either within sediments, or within rocks. Can be filled by air, water, or hydrocarbons.
Reactions that are related to the availability of oxygen. Many minerals or ions change their solubility based on redox conditions.
An interconnected set of parts that combine and make up a whole.
A sedimentary rock that formed long ago as free oxygen changed the solubility of iron, causing layers of iron rich and iron-poor sediments to form in thin layers, or bands.
A very fine grained version of silica deposited with or without microfossils.
A specific layer of rock with identifiable properties.
Original water trapped inside a forming rock.
A local or regional depression which allows sediments to accumulate.
A down-warped feature in the crust.
Metallic mineral deposit of mainly lead and zinc from groundwater movements within sedimentary rocks.
Diagenetic copper deposit within sedimentary rocks.
A type of non-eroded sediment mixed with organic matter, used by plants. Many essential elements for life, like nitrogen, are delivered to organisms via the soil.
A highly weathered soil deposit that consists of aluminum ores.
Carbonate rocks which dissolve, leaving behind caverns and holes which affect the landscape.
Breaking down of mineral material via chemical methods, like dissolution and oxidation.
The range of sediment sizes within a sediment or sediment within sedimentary rocks. Well sorted means the sediment has the same sizes, poorly sorted means many different sizes are present.
A channelled body of water.
ZrSiO4. Relatively chemically inert with a hardness of 8.5. Common accessory mineral in igneous and metamorphic rocks, as well as detrital sediments. Uranium can substitute for zirconium, making zircon a valuable mineral in radiometric dating.
The transport and movement of weathered sediments.
Toxic waters rich in heavy metals and often of low pH that come from unregulated mining districts.
CaCO3. Pure form is clear, but can take on many different colors with impurities. It is soft, fizzes in acid, and has three cleavages that are not at 90°.
Minerals bonded via a sulfate ion, SO4-2.
Porous, concentric, or layered variety of carbonate that forms with often heated water in springs and/or caves.
General name of a felsic rock that is intrusive. Has more felsic minerals than mafic minerals.
Metamorphic rock with a strong foliation but no visible minerals, derived from mudstones or shales.
A chemical sedimentary rock that forms as water evaporates.
Area where water infiltrates into the ground and adds to the overall groundwater.
An evaporite mineral, CaSo4•2H2O. Has one cleavage, hardness of 2. Typically clear or white.
Also known as rock salt, or table salt. 3 cleavages at 90°, cubic crystal habit. Typically clear or white, hardness of 3.
Volcanic tephra that is less than 2 mm in diameter.