CalicheCaliche (kəˈliːtʃiː) is a sedimentary rock, a hardened natural cement of calcium carbonate that binds other materials—such as gravel, sand, clay, and silt. It occurs worldwide, in aridisol and mollisol soil orders—generally in arid or semiarid regions, including in central and western Australia, in the Kalahari Desert, in the High Plains of the western United States, in the Sonoran Desert, Chihuahuan Desert and Mojave Desert of North America, and in eastern Saudi Arabia at Al-Hasa.
StyloliteStylolites (Greek: stylos, pillar; lithos, stone) are serrated surfaces within a rock mass at which mineral material has been removed by pressure dissolution, in a deformation process that decreases the total volume of rock. Minerals which are insoluble in water, such as clays, pyrite and oxides, as well as insoluble organic matter, remain within the stylolites and make them visible. Sometimes host rocks contain no insoluble minerals, in which case stylolites can be recognized by change in texture of the rock.
GeomechanicsGeomechanics (from the Greek prefix geo- meaning "earth"; and "mechanics") is the study of the mechanical state of the Earth's crust and the processes occurring in it under the influence of natural physical factors. It involves the study of the mechanics of soil and rock. The two main disciplines of geomechanics are soil mechanics and rock mechanics. Former deals with the soil behaviour from a small scale to a landslide scale.
PetrologyPetrology () is the branch of geology that studies rocks and the conditions under which they form. Petrology has three subdivisions: igneous, metamorphic, and sedimentary petrology. Igneous and metamorphic petrology are commonly taught together because both make heavy use of chemistry, chemical methods, and phase diagrams. Sedimentary petrology is commonly taught together with stratigraphy because it deals with the processes that form sedimentary rock. Modern sedimentary petrology is making increasing use of chemisty.
DiagenesisDiagenesis (ˌdaɪ.əˈdʒɛnəsɪs) is the process that describes physical and chemical changes in sediments first caused by water-rock interactions, microbial activity, and compaction after their deposition. Increased pressure and temperature only start to play a role as sediments become buried much deeper in the Earth's crust. In the early stages, the transformation of poorly consolidated sediments into sedimentary rock (lithification) is simply accompanied by a reduction in porosity and water expulsion (clay sediments), while their main mineralogical assemblages remain unaltered.
Mohorovičić discontinuityThe Mohorovičić discontinuity (ˌmoʊhəˈroʊvɪtʃɪtʃ ; moxorôʋiːtʃitɕ) - usually called the Moho discontinuity, Moho boundary, or just Moho - is the boundary between the crust and the mantle of Earth. It is defined by the distinct change in velocity of seismic waves as they pass through changing densities of rock. The Moho lies almost entirely within the lithosphere (the hard outer layer of the Earth, including the crust). Only beneath mid-ocean ridges does it define the lithosphere–asthenosphere boundary (the depth at which the mantle becomes significantly ductile).
HornblendeHornblende is a complex inosilicate series of minerals. It is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole. Hornblende minerals are common in igneous and metamorphic rocks. The general formula is . Hornblende has a hardness of 5–6, a specific gravity of 3.0 to 3.6, and is typically an opaque green, dark green, brown, or black color. It tends to form slender prismatic to bladed crystals, diamond-shaped in cross-section, or is present as irregular grains or fibrous masses.
Dependency grammarDependency grammar (DG) is a class of modern grammatical theories that are all based on the dependency relation (as opposed to the constituency relation of phrase structure) and that can be traced back primarily to the work of Lucien Tesnière. Dependency is the notion that linguistic units, e.g. words, are connected to each other by directed links. The (finite) verb is taken to be the structural center of clause structure. All other syntactic units (words) are either directly or indirectly connected to the verb in terms of the directed links, which are called dependencies.
LithologyThe lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples, or with low magnification microscopy. Physical characteristics include colour, texture, grain size, and composition. Lithology may refer to either a detailed description of these characteristics, or a summary of the gross physical character of a rock. Examples of lithologies in the second sense include sandstone, slate, basalt, or limestone.
Archaeological excavationIn archaeology, excavation is the exposure, processing and recording of archaeological remains. An excavation site or "dig" is the area being studied. These locations range from one to several areas at a time during a project and can be conducted over a few weeks to several years. Excavation involves the recovery of several types of data from a site.
