Earth materials

Earth materials include minerals, rocks, soil and water. These are the naturally occurring materials found on Earth that constitute the raw materials upon which our global society exists. Earth materials are vital resources that provide the basic components for life, agriculture and industry. Earth materials can also include metals and precious rocks.[1][2] [3]

Active Margin
Oceanic-continental convergence resulting in subduction and volcanic arcs illustrates one effect of plate tectonics.
Cross-cutting relations
Cross-cutting relations can be used to determine the relative ages of rock strata and other geological structures. Explanations: A – folded rock strata cut by a thrust fault; B – large intrusion (cutting through A); C – erosional angular unconformity (cutting off A & B) on which rock strata were deposited; D – volcanic dyke (cutting through A, B & C); E – even younger rock strata (overlying C & D); F – normal fault (cutting through A, B, C & E).
Alluvial Gravels at the Blue Ribbon Mine Alaska
Alluvial gravels in Alaska
Estructura-suelo
A, B, and C represent the soil profile, a notation firstly coined by Vasily Dokuchaev, the father of pedology; A is the topsoil; B is a regolith; C is a saprolite, a less-weathered regolith; the bottom-most layer represents the bedrock.

Definitions

The type of materials available locally will of course vary depending upon the conditions in the area of the building site. Take considerations of what is explained below.

In many areas, indigenous stone is available from the local region, such as limestone, marble, granite, and sandstone. It may be cut in quarries or removed from the surface of the ground (flag and fieldstone). Ideally, stone from the building site can be utilized. Depending on the stone type, it can be used for structural block, facing block, pavers, and crushed stone.

Most brick plants are located near the clay source they use to make brick. Bricks are molded and baked blocks of clay. Brick products come in many forms, including structural brick, face brick, roof tile, structural tile, paving brick, and floor tile.

Caliche is a soft limestone material which is mined from areas with calcium-carbonate soils and limestone bedrock. It is best known as a road bed material, but it can be processed into an unfired building block, stabilized with an additive such as cement. Other earth materials include soil blocks typically stabilized with a cement additive and produced with forms or compression.

Rammed Earth consists of walls made from moist, sandy soil, or stabilized soil, which is tamped into form work. Walls are a minimum of 12″ thick. Soils should contain about 30% clay and 70% sand. [4]

Considerations

The use of locally available and indigenous earth materials has several advantages in terms of sustainability. They are:

Reduction of energy costs related to transportation. Reduction of material costs due to reduced transportation costs, especially for well-established industries. Support of local businesses and resource bases. Care must be taken to ensure that non-renewable earth materials are not over-extracted. Ecological balance within the region needs to be maintained while efficiently utilizing its resources. Many local suppliers carry materials that have been shipped in from out of the area, so it is important to ask for locally produced/quarried materials.

Both brick and stone materials are aesthetically pleasing, durable, and low maintenance. Exterior walls weather well, eliminating the need for constant refinishing and sealing. Interior use of brick and stone can also provide excellent thermal mass, or be used to provide radiant heat. Some stone and brick makes an ideal flooring or exterior paving material, cool in summer and possessing good thermal properties for passive solar heating. Caliche block has been produced for applications similar to stone and brick mentioned above. Caliche or earth material block has special structural and finishing characteristics.

Rammed earth is more often considered for use in walls, although it can also be used for floors. Rammed earth and caliche block can be used for structural walls, and offer great potential as low-cost material alternatives with low embodied energy. In addition, such materials are fireproof.

Caliche block and rammed earth can be produced on-site. It is very important to have soils tested for construction material use. Some soils, such as highly expansive or bentonite soils, are not suitable for structural use. Testing labs are available in most areas to determine material suitability for structural use and meeting codes.

Soils for traditional adobe construction are not found in some areas, but other soils for earth building options are available. Many areas have a high percentage of soils suitable for ramming. (Official areas are approximately 19,610 acres in the Austin, TX area, according to the US. Department of Agriculture).

Caliche is also abundant in many areas (covering 14% of the Austin geographic area, for instance) and is readily available locally. [5] [6]

See also

References

  1. ^ Study.com, Earth materials
  2. ^ Earth Materials: Introduction to Mineralogy and Petrology, by Cornelis Klein, Anthony R. Philpotts
  3. ^ Principles of Sedimentology and Stratigraphy, by Sam Boggs Jr.
  4. ^ earthlearningidea.com, Earth Materials
  5. ^ Utrecht University Library, Earth materials
  6. ^ MIT, Earth materials

External links

Caloosahatchee culture

The Caloosahatchee culture is an archaeological culture on the Gulf coast of Southwest Florida that lasted from about 500 to 1750 CE. Its territory consisted of the coast from Estero Bay to Charlotte Harbor and inland about halfway to Lake Okeechobee, approximately covering what are now Charlotte and Lee counties. At the time of first European contact, the Caloosahatchee culture region formed the core of the Calusa domain.

Some Archaic artifacts have been found in the Caloosahatchee culture region, including one site classified as early Archaic. There is evidence that Charlotte Harbor aquatic resources were being intensively exploited before 3500 BC. Undecorated pottery belonging to the early Glades culture appeared in the region around 500 BC. Pottery distinct from the Glades tradition developed in the Caloosahatchee region around 500 AD, and a complex society with high population densities developed by 800 AD. Later periods in the Caloosahatchee culture are defined by the appearance of pottery from other traditions in the archaeological record.

The coast in the Caloosahatchee culture region is a very rich estuarine environment. An extensive network of bays and sounds are protected behind barrier islands. The Caloosahatchee, Myakka and Peace rivers flow into the estuary. There are extensive areas of mangrove and seagrass in the estuary, resulting in high biological production.

The people of the Caloosahatchee culture built mounds. Some of the mounds in Caloosahatchee settlements were undisturbed shell middens, but other were constructed from midden and earth materials. The hundreds of sites identified range from simple small middens to complex sites with earthwork platform mounds, plazas, "water courts," causeways, and canals. Mound Key, in the middle of Estero Bay, covers 70–80 acres (28–32 ha), and includes mounds up to 31 feet (9.4 m) tall. A canal penetrates more than halfway into Mound Key, passing between two mounds and ending in a roughly rectangular pool.

The Caloosahatchee people derived 80% to 90% of their animal food from fish. Shellfish, including crabs were also important. Minor components of their diet included white-tailed deer, other mammals, waterfowl such as ducks, American Alligators, turtles, West Indian Manatees and sea urchins. Plants collected as food included various wild roots, mastic fruit, prickly pear cactus fruit, palm fruits, sea grapes, hogplum, and cocoplum.

Tools and ornaments made of wood, bone, stone and shell have been found. Perforated stones and plummets (oblong stones with a groove incised around one end) of limestone are though to have been used as fishing net weights. Dippers, cups, spoons, beads, cutting-edge tools and hammers were made from shells. Awls, beads, pendants, pins, gorges, barbs, and points were made from bone. Ceremonial tablets were incised on non-native stone (presumably imported from other areas).

Although outside the Caloosahatchee region proper, the artifacts found at Key Marco are closely related. These include many wood objects and cordage. The cordage found at Key Marco, probably of palm fiber, was primarily used in fishing nets. Wood artifacts found at Key Marco included masks, painted carvings of animals, incised and painted tablets and toy/model canoes.

Cosmogenic nuclide

Cosmogenic nuclides (or cosmogenic isotopes) are rare nuclides (isotopes) created when a high-energy cosmic ray interacts with the nucleus of an in situ Solar System atom, causing nucleons (protons and neutrons) to be expelled from the atom (see cosmic ray spallation). These isotopes are produced within Earth materials such as rocks or soil, in Earth's atmosphere, and in extraterrestrial items such as meteorites. By measuring cosmogenic isotopes, scientists are able to gain insight into a range of geological and astronomical processes. There are both radioactive and stable cosmogenic isotopes. Some of these radioisotopes are tritium, carbon-14 and phosphorus-32.

Certain light (low atomic number) primordial nuclides (some isotopes of lithium, beryllium and boron) are thought to have arisen not only during the Big Bang, and also (and perhaps primarily) to have been made after the Big Bang, but before the condensation of the Solar System, by the process of cosmic ray spallation on interstellar gas and dust. This explains their higher abundance in cosmic rays as compared with their ratios and abundances of certain other nuclides on Earth. This also explains the overabundance of the early transition metals just before iron in the periodic table; the cosmic-ray spallation of iron thus produces scandium through chromium on one hand and helium through boron on the other. However, the arbitrary defining qualification for cosmogenic nuclides of being formed "in situ in the Solar System" (meaning inside an already-aggregated piece of the Solar System) prevents primordial nuclides formed by cosmic ray spallation before the formation of the Solar System, from being termed "cosmogenic nuclides"— even though the mechanism for their formation is exactly the same. These same nuclides still arrive on Earth in small amounts in cosmic rays, and are formed in meteoroids, in the atmosphere, on Earth, "cosmogenically." However, beryllium (all of it stable beryllium-9) is present primordially in the Solar System in much larger amounts, having existed prior to the condensation of the Solar System, and thus present in the materials from which the Solar System formed.

To make the distinction in another fashion, the timing of their formation determines which subset of cosmic ray spallation-produced nuclides are termed primordial or cosmogenic (a nuclide cannot belong to both classes). By convention, certain stable nuclides of lithium, beryllium, and boron are thought to have been produced by cosmic ray spallation in the period of time between the Big Bang and the Solar System's formation (thus making these primordial nuclides, by definition) are not termed "cosmogenic," even though they were formed by the same process as the cosmogenic nuclides (although at an earlier time). The primordial nuclide beryllium-9, the only stable beryllium isotope, is an example of this type of nuclide.

In contrast, even though the radioactive isotopes beryllium-7 and beryllium-10 fall into this series of three light elements (lithium, beryllium, boron) formed mostly by cosmic ray spallation nucleosynthesis, both of these nuclides have half lives too short for them to have been formed before the formation of the Solar System, and thus they cannot be primordial nuclides. Since the cosmic ray spallation route is the only possible source of beryllium-7 and beryllium-10 occurrence naturally in the environment, they are therefore cosmogenic.

Duncan Haldane

Frederick Duncan Michael Haldane (born 14 September 1951), known as F. Duncan Haldane, is a British born physicist who is currently the Sherman Fairchild University Professor of Physics at Princeton University, and a Distinguished Visiting Research Chair at Perimeter Institute for Theoretical Physics. He is a co-recipient of the 2016 Nobel Prize in Physics, along with David J. Thouless and John Michael Kosterlitz.

Economic geology

Economic geology is concerned with earth materials that can be used for economic and/or industrial purposes. These materials include precious and base metals, nonmetallic minerals, construction-grade stone, petroleum minerals, coal, and water. Economic geology is a subdiscipline of the geosciences; according to Lindgren (1933) it is “the application of geology”. Today, it may be called the scientific study of the Earth’s sources of mineral raw materials and the practical application of the acquired knowledge. The term commonly refers to metallic mineral deposits and mineral resources. The techniques employed by other earth science disciplines (such as geochemistry, mineralogy, geophysics, petrology and structural geology) might all be used to understand, describe, and exploit an ore deposit.

Economic geology is studied and practiced by geologists. Economic geology may be of interest to other professions such as engineers, environmental scientists, and conservationists because of the far-reaching impact that extractive industries have on society, the economy, and the environment.

Excavatability

The excavatability of an earth (rock and regolith) material is a measure of the material to be excavated (dug) with conventional excavation equipment such as a bulldozer with rippers, backhoe, scraper and other grading equipment. Materials that cannot be excavated with conventional excavation equipment are said to be non-rippable. Such material typically requires pre-blasting or use of percussion hammers or chisels to facilitate excavation. The excavatability or rippability of earth materials is evaluated typically by a geophysicist, engineering geologist, or geotechnical engineer.

Formation evaluation gamma ray

The formation evaluation gamma ray log is a record of the variation with depth of the natural radioactivity of earth materials in a wellbore. Measurement of natural emission of gamma rays in oil and gas wells are useful because shales and sandstones typically have different gamma ray levels. Shales and clays are responsible for most natural radioactivity, so gamma ray log often is a good indicator of such rocks. In addition, the log is also used for correlation between wells, for depth correlation between open and cased holes, and for depth correlation between logging runs.

Geodiversity

Geodiversity is the variety of earth materials, forms and processes that constitute and shape the Earth, either the whole or a specific part of it. Relevant materials include minerals, rocks, sediments, fossils, soils and water. Forms may comprise folds, faults, landforms and other expressions of morphology or relations between units of earth material. Any natural process that continues to act upon, maintain or modify either material or form (for example tectonics, sediment transport, pedogenesis) represents another aspect of geodiversity. However geodiversity is not normally defined to include the likes of landscaping, concrete or other significant human influence.

Geologic hazards

A geologic hazard is one of several types of adverse geologic conditions capable of causing damage or loss of property and life. These hazards consist of sudden phenomena and slow phenomena:

Sudden phenomena include:

avalanches (snow, rock, or air & snow) and its runout

earthquakes and earthquake-triggered phenomena such as tsunamis

forest fires (espec. in Mediterranean areas) leading to deforestation

geomagnetic storms

ice jams (Eisstoß) on rivers or glacial lake outburst floods below a glacier

landslide (lateral displacement of earth materials on a slope or hillside)

mudflows (avalanche-like muddy flow of soft/wet soil and sediment materials, narrow landslides)

pyroclastic flows

rock falls, rock slides, (rock avalanche) and debris flows

torrents (flash floods, rapid floods or heavy current creeks with irregular course)

volcanic eruptions, lahars and ash falls.Gradual or slow phenomena include:

alluvial fans (e.g. at the exit of canyons or side valleys)

caldera development (volcanoes)

geyser deposits

ground settlement due to consolidation of compressible soils or due to collapseable soils (see also compaction)

ground subsidence, sags and sinkholes

liquefaction (settlement of the ground in areas underlain by loose saturated sand/silt during an earthquake event)

sand dune migration

shoreline and stream erosion

thermal springsSometime the hazard is instigated by man through the careless location of developments or construction in which the conditions were not taken into account.

Geotechnical engineering

Geotechnical engineering is the branch of civil engineering concerned with the engineering behavior of earth materials. Geotechnical engineering is important in civil engineering, but also has applications in military, mining, petroleum and other engineering disciplines that are concerned with construction occurring on the surface or within the ground. Geotechnical engineering uses principles of soil mechanics and rock mechanics to investigate subsurface conditions and materials; determine the relevant physical/mechanical and chemical properties of these materials; evaluate stability of natural slopes and man-made soil deposits; assess risks posed by site conditions; design earthworks and structure foundations; and monitor site conditions, earthwork and foundation construction.A typical geotechnical engineering project begins with a review of project needs to define the required material properties. Then follows a site investigation of soil, rock, fault distribution and bedrock properties on and below an area of interest to determine their engineering properties including how they will interact with, on or in a proposed construction. Site investigations are needed to gain an understanding of the area in or on which the engineering will take place. Investigations can include the assessment of the risk to humans, property and the environment from natural hazards such as earthquakes, landslides, sinkholes, soil liquefaction, debris flows and rockfalls.

A geotechnical engineer then determines and designs the type of foundations, earthworks, and/or pavement subgrades required for the intended man-made structures to be built. Foundations are designed and constructed for structures of various sizes such as high-rise buildings, bridges, medium to large commercial buildings, and smaller structures where the soil conditions do not allow code-based design.

Foundations built for above-ground structures include shallow and deep foundations. Retaining structures include earth-filled dams and retaining walls. Earthworks include embankments, tunnels, dikes and levees, channels, reservoirs, deposition of hazardous waste and sanitary landfills.

Geotechnical engineering is also related to coastal and ocean engineering. Coastal engineering can involve the design and construction of wharves, marinas, and jetties. Ocean engineering can involve foundation and anchor systems for offshore structures such as oil platforms.

The fields of geotechnical engineering and engineering geology are closely related, and have large areas of overlap. However, the field of geotechnical engineering is a specialty of engineering, where the field of engineering geology is a specialty of geology. Coming from the fields of engineering and science, respectively, the two may approach the same subject, such as soil classification, with different methods.

Geotechnics

Geotechnics is the application of scientific methods and engineering principles to the acquisition, interpretation, and use of knowledge of materials of the Earth's crust and earth materials for the solution of engineering problems and the design of engineering works. It is the applied science of predicting the behavior of the Earth, its various materials and processes towards making the Earth more suitable for human activities and development.

Geotechnics embraces the fields of soil mechanics and rock mechanics, and many of the aspects of geology, geophysics, hydrology, and other related sciences. Geotechnics is practiced by both engineering geologists and geotechnical engineers.

Examples of the application of geotechnics include: the prediction, prevention or mitigation of damage caused by natural hazards such as avalanches, mud flows, landslides, rockslides, sinkholes, and volcanic eruptions; the application of soil, rock and groundwater mechanics to the design and predicted performance of earthen structures such as dams; the design and performance prediction of the foundations of bridges, buildings, and other man-made structures in terms of the underlying soil and/or rock; and flood control and prediction.

Heap leaching

Heap leaching is an industrial mining process used to extract precious metals, copper, uranium, and other compounds from ore using a series of chemical reactions that absorb specific minerals and re-separate them after their division from other earth materials. Similar to in situ mining, heap leach mining differs in that it places ore on a liner, then adds the chemicals via drip systems to the ore, whereas in situ mining lacks these liners and pulls pregnant solution up to obtain the minerals. Most mining companies favor the economic feasibility of heap leaching, considering that heap leaching is a better alternative to conventional processing methods such as such as flotation, agitation, and vat leaching.Additionally, dump leaching is an essential part of most copper mining operations and etermines the quality grade of the produced material along with other factors. Due to the profitability that the dump leaching has on the mining process, i.e. it can contribute substantially to the economic viability of the mining process, it is advantageous to include the results of the leaching operation in the economic overall project evaluation. This, in effect, requires that the key controllable variables, which have an effect on the recovery of the metal and the quality of solution coming from a dump leaching process.The process has ancient origins; one of the classical methods for the manufacture of copperas (iron sulfate) was to heap up iron pyrite and collect the leachate from the heap, which was then boiled with iron to produce iron(II) sulfate.

Lehmann discontinuity

The Lehmann discontinuity is an abrupt increase of P-wave and S-wave velocities at the depth of 220±30 km, discovered by seismologist Inge Lehmann. It appears beneath continents, but not usually beneath oceans, and does not readily appear in globally averaged studies. Several explanations have been proposed: a lower limit to the pliable asthenosphere, a phase transition, and most plausibly, depth variation in the shear wave anisotropy. Further discussion of the Lehmann discontinuity can be found in the book Deformation of Earth Materials by Shun-ichirō Karato.

Lutetium–hafnium dating

Lutetium–hafnium dating is a geochronological dating method utilizing the radioactive decay system of lutetium–176 to hafnium–176. With a commonly accepted half-life of 37.1 billion years, the long-living Lu–Hf decay pair survives through geological time scales, thus is useful in geological studies. Due to chemical properties of the two elements, namely their valences and ionic radii, Lu is usually found in trace amount in rare-earth element loving minerals, such as garnet and phosphates, while Hf is usually found in trace amount in zirconium-rich minerals, such as zircon, baddeleyite and zirkelite.The trace concentration of the Lu and Hf in earth materials posed some technological difficulties in using Lu–Hf dating extensively in the 1980s. With the use of inductively coupled plasma mass spectrometry (ICP–MS) with multi-collector (also known as MC–ICP–MS) in later years, the dating method is made applicable to date diverse earth materials. The Lu–Hf system is now a common tool in geological studies such as igneous and metamorphic rock petrogenesis, early earth mantle-crust differentiation, and provenance.

Parametric array

A parametric array, in the field of acoustics, is a nonlinear transduction mechanism that generates narrow, nearly side lobe-free beams of low frequency sound, through the mixing and interaction of high frequency sound waves, effectively overcoming the diffraction limit (a kind of spatial 'uncertainty principle') associated with linear acoustics. The main side lobe-free beam of low frequency sound is created as a result of nonlinear mixing of two high frequency sound beams at their difference frequency. Parametric arrays can be formed in water, air, and earth materials/rock.

Sean Cadogan

John M. (Sean) Cadogan is Professor of Physics at the University of New South Wales and a former Canada Research Chair in Advanced Materials.Using advanced nuclear techniques, he studies the magnetic compounds formed between rare earth elements and transition elements. Materials with magnetic properties have played a central role in the development of modern technology, and are used in many every-day devices. Rare-earth materials promise magnetic properties beyond the capabilities of those used in the past and so are essential to the continued evolution and development of new technologies. They also have the potential to improve energy efficiency in applications ranging from advanced motors to new refrigeration technologies, and to reduce the environmental side effects of current technology.

Cadogan also uses nuclear techniques to explore "soft-magnetic" materials based on iron and other elements, which are found in such applications as the transformer cores used by the electrical power industry

Slaking (geology)

Slaking is the process in which earth materials disintegrate and crumble when exposed to moisture. The term can be applied to natural geologic formations, land modified by or for human use, or to the use of earth materials in manufacturing or industry.

This process can often lead to erosion if the geologic area is not flat or vegetated. The slaking property does not necessarily have to be in the A horizon, with B horizon slaking only becoming a problem when the A horizon is disturbed or eroded away.

Spoil tip

A spoil tip (also called a spoil bank, boney pile, gob pile, bing, batch, boney dump or pit heap) is a pile built of accumulated spoil – the overburden or other waste rock removed during coal and ore mining. These waste materials are typically composed of shale, as well as smaller quantities of carboniferous sandstone and various other residues. Spoil tips are not formed of slag, but in some areas they are referred to as slag heaps.

The term "spoil" is also used to refer to material removed when digging a foundation, tunnel, or other large excavation. Such material may be ordinary soil and rocks, or may be heavily contaminated with chemical waste, determining how it may be disposed of. Clean spoil may be used for land reclamation.

Spoil is distinct from tailings, which is the processed material that remains after the valuable components have been extracted from ore.

Symplectite

A symplectite (or symplektite) is a material texture: a micrometre-scale or submicrometre-scale intergrowth of two or more crystals. Symplectites form from the breakdown of unstable phases, and may be composed of minerals, ceramics, or metals. Fundamentally, their formation is the result of slow grain-boundary diffusion relative to interface propagation rate.If a material undergoes a change in temperature, pressure or other physical conditions (e.g., fluid composition or activity), one or more phases may be rendered unstable and recrystallize to more stable constituents. If the recrystallized minerals are fine grained and intergrown, this may be termed a symplectite. A cellular precipitation reaction, in which a reactant phase decomposes to a product phase with the same structure as the parent phase and a second phase with a different structure, can form a symplectite. Eutectoid reactions, involving the breakdown of a single phase to two or more phases, neither of which is structurally or compositionally identical to the parent phase, can also form symplectites.Symplectites may be formed by reaction between adjacent phases or to decomposition of a single phase. The intergrown phases may be planar or rodlike, depending on the volume proportions of the phases, their interfacial free energies, the rate of reaction, the Gibbs free energy change, and the degree of recrystallization. Lamellar symplectites are common in retrogressed eclogite. Kelyphite is a symplectite formed from the decomposition of garnet. Myrmekite is a globular or bulbous symplectite of quartz in plagioclase.Examples of symplectites formed in Earth materials include

dolomite + calcite, aragonite + calcite, and magnetite + clinopyroxene.

Symplectite formation is important in metallurgy: bainite or pearlite formation from the decomposition of austenite, for example.

William Gilbert Award

The William Gilbert Award is presented annually by the Geomagnetism and Paleomagnetism section of the American Geophysical Union and is "in recognition of outstanding and unselfish work in magnetism of Earth materials and of the Earth and planets." The awardees are chosen based on demonstrated excellence in: (1) scientific rigor, originality, and impact; (2) leadership and service to the geomagnetism and paleomagnetism research community; and/or (3) development of new cross-disciplinary research areas and methods. Every other year, the award is designated for an early-career scientist. The award is named after William Gilbert who first proposed the concept of a geomagnetic field in De Magnete (published in 1600).

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