It is rarely exposed, and it forms the base of an entire sedimentary formation. For example, a fault that varies from steep to flat and back to steep again has a ramp-flat-ramp geometry . It can be simply defined as the interconnection of biological and physical components of our planet. Chert is found in different colors like brown, gray, white, rusty red, etc. It is a cobble, pebble, or a boulder that is faceted by wind-driven sand. This era lies between the Paleozoic and Cenozoic. Some of the examples are rhyolite and granite. Sedimentary rocks are layered and have been formed from the sediment or loose particles of older rocks. It is also called impact metamorphism, and it takes place when extremely high pressure acts on a rock for a few minutes or few seconds. This arises from the action of water on them. It is a type of texture seen in igneous rocks that are made up of very fine crystals and/or mineral particles that cannot be identified with naked eyes. Due to removal of crystals, the percentage of silica in the magma increases gradually. It is an extrusive dark-colored igneous rock that is characteristically formed at the mid-oceanic regions. Geology Glossary - Definitions of Geologic Terms Geology is the scientific study of the Earth, the materials of which it is made, the structure of those materials, and the processes acting upon them. Geology Key Terms Such a kind of river flows in the backswamp area, parallel to the main stream. A sea vent formed due to superheated water that flows from the Earth’s crust to the ocean floor is called black smoker. Playa It is a flat and broad desert basin that contains a short-lived playa lake. The topmost unconsolidated layer of the Earth’s crust, which is forms due to the erosion of preexisting rocks is known as soil. Angular or rotational movement of a fault on one side of the hinge is called hinge fault, and it is always perpendicular to the fault plane. It is a type of physical or mechanical weathering, wherein rocks that were joined together are separated due to expansion of water. This zone is characterized by the loss of ice due to melting, calving, or sublimation into water. Anticline is a fold in a rock and is convex-shaped. It is a chronological order of the events that help to explain the formation of rocks and evolution of organisms on Earth, over different units of time. It can be defined as a physical characteristics of a soil that is related to the grain size of the minerals present in the soil. Desert Geological Terms Definitions of Important Geological Features About one-third of the earth's landmass is desert or semi-desert. This deposition leads to an angular discordance with horizontal layers that are overlaid. It is developed from shale, and can break into thin sheets due to its foliated nature. The logarithmic scale that measures the intensity or strength of an earthquake is called Richter scale. It is opposite to the wave trough, which is the lowest part of a wave. Glaciers are masses of snow and ice that usually range in size from approximately 328 feet (100 meters) to roughly 6,213 miles (10,000 kilometers). Minerals that contain magnesium and iron are called ferromagnesian. It consists of deposits known as ’till’, which are carried by the glacier ice down the valley. A glossary of common climate change and meteorological terms. A tributary in an U-shaped glacial valley that enters the valley at a higher elevation, instead of the same level as that of a main stream, is known as a hanging valley. This age can be of any term that includes geological events or related parameters. It started somewhere around 2 million years ago, and is still continuing till the present (according to some theories). An igneous rock whose chemical composition lies between acidic and basic rocks is known as an intermediate rock. Learn geology terms with free interactive flashcards. The primary waste that originates from the manufacturing and development of nuclear weapons is called high level nuclear waste. The regions where earthquakes do not occur are called aseismic regions. Thus, abrasion is the frictional process between moving particles and stationary rocks. Peat It is the lowest grade coal, and is formed because of partial decomposition of plant and animal matter, under varying degrees of overlying pressure. It is a metamorphic rock formed through the process of regional metamorphism. These rocks are formed along the floor or walls of the caves along which water flows. Suture zones are the areas where two continental or converging plates meet through collision. Paleozoic Era It is an era marked by the presence of fish, amphibians, insects, and marine invertebrates. It is a fold that is made up of different layers with every layer oriented in the same direction. Adit: A horizontal mine tunnel (see also shaft). Those rocks that are formed from molten magma are known as igneous rocks. Phyllite It is a low-grade metamorphic rock, which is mainly formed due to regional metamorphism of sandstone. In French, butte means “small hill”. It is the upper mantle of the Earth that is present just below lithosphere. Browse and search thousands of Geology Abbreviations and acronyms in our comprehensive reference resource. Almost 80 percent of the Earth’s surface is covered by these rocks. It also provides tools to determine the relative and absolute ages of rocks found in a given location, and also to describe the histories of those rocks. The magnitude is usually less than the main earthquake, and near the epicenter of the main earthquake. Mauna Loa is the world’s largest active volcano. It is the principle that encompasses the laws of nature that are constant. The snow/ice is lost from the glaciers, and these erosive processes include evaporation, wind erosion, calving, melting, etc. It is formed by the decomposition of dead plants, and contains more than 50% of carbon compounds. This can be in the form of sea mounts, volcanic arcs, or sediments. It is a type of limestone that is made up of calcite. It is a dry bed or gulch that fills with water seasonally due to heavy rains. In this process, the glacier undergoes thawing at its base, resulting in its movement. They mainly are cavities that are lined with crystals from the inside. It is a type of coal that has the maximum percentage of carbon (92 – 98%). This layer is made up of soft and mobile rocks, and it is called the ‘weak zone’. It is located at 100 to 200 km below the Earth’s crust, and extends approximately up to 400 km. It is also called accretionary prism, and it is formed by the process of accretion. The water level in the ocean below which calcium carbonate does not exist is called carbonate conservation depth. During this process, the lime that dissolves in water acts as a cementing material to bond together the total mass. It is a permeable and porous rock, from which natural gas or oil can be obtained. Hydraulic head - The height above a datum plane (such as sea level) of the column of water that can be supported by the hydraulic pressure at a given point in a ground water system. It is a fan-shaped wedge that is formed by the accumulation of sediments left by a fast-flowing stream, when it slows down and spreads in a fan-shaped fashion at the canyon exit. Although you might not be able to give a precise definition of a gem at this time, few of you would have any trouble in recognizing that the images below are of gems. When the molten magma heats the water present beneath the Earth’s surface, a lot of steam and high pressure is generated, and on releasing the pressure, the water along with steam instantly rises upwards and shoots out of the geyser vent. Pedalfer It is a common type of soil found in humid regions, and is characterized by the abundance of iron oxides and clay minerals. It is a model that describes the movement of water in the hydrosphere, lithosphere, atmosphere, and biosphere. They can appear as flat or curved. Like all specialized sciences, it has a vocabulary all its own. It is a type of silicate mineral and is opaque and cryptocrystalline in nature. The main aim of geological research is to study the history of our planet, along with the gradual changes in the Earth materials and living organisms, due to various processes that took place over vast time periods. These plains are usually found at a depth of 6,500 ft below the mean sea level. Besides the enormity and natural beauty of the place, trying to find out about the formation of a waterfall,…, Building rock tumblers is a project that can help children understand the geological process of the tumbling and smoothing of rocks in water bodies. They are the arrangement of certain minerals in deposits, along with sedimentary structure, which help in categorizing different types of sedimentary rocks according to their depositional environment. This happens due to the different compositions and resistance of rocks to weathering. It is a group of minerals that describe the characteristics of a rock/facies. Some of the common minerals that form augen structures are quartz, feldspar, and garnet. It occurs between metamorphic or igneous and sedimentary rock, and marks a change in the type of depositional environment. This type of well is characterized by pumping of water from confined aquifers to the surface due to the high pressure acting on the water level. Simply said, it is the thinning of the ozone layer in the Earth’s atmosphere due to high level of pollution. It means the removal of the surface material below the snow line due to various erosive processes. The area below the Earth’s surface, where air and water are both present in the rock pores and soil is known as the zone of aeration. The magnitude of the earthquake is measured by finding the logarithm of the amplitude of waves that are generated by the seismograph. Pirate Stream The type of stream that captures the origin or headwaters of another stream is known as pirate stream. It is usually formed in desert regions with less sand and stable wind directions. During the hardening process, the calcium carbonate in the rock cements together other sediments like clay, silt, sand, and gravel. It is the deposition of sediments in a layered manner, such that the materials can be easily differentiated. It is a type of stream/river drainage pattern, which appears like dendrites that are joined to each other at acute angles. Pegmatites are coarse-grained in nature as the mineral grains grow slowly due to slow cooling of the magma under the crustal portions. The accumulation of molten lava in a crater that is formed due to volcanic eruption is known as a lava lake. It is defined as the cycle of formation and destruction of ocean basins and associated mountain ranges. It is an evidence or a trace of dead animals and plants that are buried under sedimentary strata. It is a fold that is convex in downward direction, and the central part of this fold is considered as the youngest portion of the rock. This classification is based on the physical and chemical properties of different types of soil. In plate tectonics, triple junction is the region where three plate boundaries or associated rifts are joined together at approximately 120 degrees angle. It is usually takes place when a meteorite strikes the Earth. These waves are generated due to an eruption, explosion, or an earthquake, and that travel through the Earth. A seamount whose top is flat due to weathering is called Guyot. It is mainly made up of alloys of iron and nickel, and is situated around 6,370 km below the Earth’s crust. This rock consists of more than 66% of combined or free silica. Many geology terms specify the physical formations a geologist studies to reach conclusions about changes in the Earth’s surface. Such domes are usually formed in igneous rocks. Thus, it can be called a set of processes that brings a change in sediments once they are deposited. These cookies do not store any personal information. It is a type of basaltic lava that has a high speed of flowing and cools down to form rough and scraggy-surfaced igneous rocks. The area or segment of an earthquake susceptible zone that has not undergone tremors, in spite of them occurring in the other regions, is known as a seismic gap. Certain rocks or minerals to break along specific planes where weak bonds are present. phyllite This kind of landscape or topography is formed or developed in a region, where limestone and dolomite rocks are mainly present. This technique uses the penetration power of X-rays, wherein they are made to penetrate the powder samples of the rocks under study, to get an idea about their elemental composition. It is a glacial drift composed of rock fragments ranging from clay to boulders. It is a naturally formed arch-shaped rock formation that is a result of weathering or erosion. It is a depression formed on the surface of ground due to the melting of buried glacier ice. This region of floodplains is characterized by fine silt and clay deposition that occurs after a flood. The coastal environment of the world is made up of a wide variety of landforms manifested in a spectrum of sizes and shapes ranging from gently sloping beaches to high cliffs, yet coastal landforms are … It is a type of strike-slip fault found along mid-ocean ridges. This wave transmits energy in all the directions from the earthquake’s focus through the interior of the Earth. These rocks are composed of organic debris particles that rederived from preexisting rocks. These rocks contain mafic minerals like olivine, pyroxene, augite, etc., and are dark in color. This metamorphic rock is formed by the process of recrystallization. This type of lake is formed due to erosion and deposition in the river channel. In this process, the speed of the subducting plate is more than the overriding plate. It is composed of minerals, like aluminum or iron, or any organic material that is deposited by the process of leaching. This layer is less organic in nature, and is characterized by very less weathering. The term “aa” has a Hawaiian origin. It is the oldest section of the rock. This silicate mineral is cryptocrystalline in nature, and it is made up of very fine inter-growths of moganite and quartz. The factors that are altered include chemical composition, structure/texture, and mineral content of the parent rock. Geology is the science that deals with the history of the Earth and its life through the study of the Earth’s crust and rocks. It consists of the change of rocks into its particular classes, i.e., igneous, sedimentary, and metamorphic. This is a layer of filamentous algae formed in a sequential manner of wetting, algal formation, and drying, at the bottom of freshwater or marine water. It contains acidic compounds like nitric acid and sulfuric acid. Well, we're looking for good writers who want to spread the word. In this process, water bodies like lakes, streams, or any slowing moving river acquire excess nutrients that results into increased plant growth, and thereby, reduces the amount of oxygen in the water, leading to the death of other organisms living in the same body. When the size of the alpine glacier grows and fills a valley, it is called a valley glacier. It is a deep and active seismic area near the subduction zone. It is the by-product left in the nuclear reactor after the nuclear fuel has been consumed. Biogenic sediment is a skeletal deposition that results due to physiological processes or activities of living organisms. The pits or depressions are known as sinkholes. They are found in metamorphic rocks. It is a type of sedimentary deposition caused due to turbid water carrying particles of varying sizes. This deformation or alteration is made up of igneous, metamorphic, and sedimentary rocks. An eon can be called the major or primary division of geologic time scale. Also known as Benioff zone, it can be up to 700 km deep. It is the process of reduction in porosity of a sediment due to the effect of loading of the deposition above it. These deserts are located in the interior part of a continent, and remain dry for most part of the year. These storms take place when dust particles travel in large amounts and spread over a very large area of an arid region. GEOLOGY 115 LESSON 1: BASIC TERMS What is a gem? These wedges are mostly made up of sediments accreted on a subducting tectonic plate, at the boundary of a convergent plate. Phanerozoic It is the current eon (longest division of geological time) that began 570 million years ago, and is continuing till date. Oxidation and hydrolysis are some of the most common chemical alteration processes that take place. The ground is saturated with water below the surface of the water table. The index that represents the ratio of annual evaporation to the solar radiation received by an area is called aridity index. These metal sulfide deposits are formed after a volcanic eruption takes place. Alpine glaciers are formed on the slopes of a mountain. It helps to find out the degree of metamorphism underwent by the parent rock. The term “oxbow” is used to refer to a part of the river that is U-shaped. The movement of the rock takes place along this crack. This study also includes the age of the rock and other related parameters. Bar is a deposition of sediments that generally consist of sand or gravel and is usually formed in river mouths, river, border of a stream, or offshore waters. They are sedimentary rocks that are made up of particles derived from pre-existing rocks. This term refers to an igneous rock containing many vesicles, which were formed due to the expansion of gases (which were earlier dissolved in lava). In this process, the surface particles of a rock get worn off or loosened, and are transported to some other place by air (wind), water, gravity, or ice. Thus, due to the effect or action of ground water and surface water, sinkholes, caves, underground drainage, disappearing streams, etc., are some of the typical characteristics that develop in such regions. The exploration of oil, minerals, and metals helps find out the presence of these materials on our planet. Footprints imprinted on rocks, bones of ancient humans and animals, shells, etc., are a few examples. These regions have unique geologic features not found in more humid environments. An igneous rock that is derived from the mantle, which contains a high percentage of magnesium oxide is known as komatiite. Geology is the study of Earth science. The molten magma that is discharged through fissures or volcanic vents on the Earth’s surface is known as lava. Several depressions or pits in the ground surface are formed due to erosion of rocks like limestone and dolomite. It is defined as the boundary formed between two lithologies due to a period of erosion or non-deposition. Rocks that are formed due to the process of metamorphism are called metamorphic rocks. Pangaea It is an ancient continent from which the present continents are formed, due to breaking up and spreading of the sea floor. It is the study of measuring the depths of ocean floors and preparing topographic maps. Weathering takes place on the surface of the Earth. A narrow and long island, which is made up of sand due to the action of waves that run parallel to the shore is known as a barrier island. Such material mainly consist of glass fragments, ash, volatile substances, etc. The definitions in this book are drawn largely from the autoritative 36,000-term Glossary Of Geology, to which nearly 150 specialists from all fields of the geosciences contributed. It is a layer that contains a higher percentage of clay. Rise of the water above this level indicates occurrence of flood. It is a hot, dense cloud of volcanic ash and gas generated in a Plinian volcanic eruption. Watershed, also known as drainage basin, separates two adjacent water systems. It is a type of surface seismic wave that is produced during an earthquake. Start studying Geology terms. B) Back reef, Bacteria, Basin, Batholith, Bedrock, Burning, Butte. Coastal landforms, any of the relief features present along any coast, the result of a combination of processes, sediments, and the geology of the coast itself. It is the process in which the molten lava escapes through the Earth’s core and becomes cool to form hard rocks. There are a number of common geology terms one will encounter when considering scientific issues that have to do with the Earth’s composition. They can also be made up of marine sediments and volcanic island arcs. This portion has a thickness of about 2,260 km. This changes the composition of the magma and generates igneous rocks with different properties and composition. The displacement or mixing of sediments by animals and plants is called bioturbation. Other geology terms refer to the minerals that make up rocks. It is defined as the structure or arrangement of a class of minerals in a parallel manner, such that they form sheet-like layers. It is a crescent-shaped dune formed due to wind action, and moves across the desert. Sign up to receive the latest and greatest articles from our site automatically each week (give or take)...right to your inbox. These particles are called clasts. This process usually takes place in warmer or temperate areas, and due to the slipping movement, it is known as basal sliding. It is defined as the area or surface present between the zone of aeration and the zone of saturation. They are formed by intrusion of magma into preexisting rocks. These faults are caused due to the movement present between crustal plates. It is the geologic time period that existed between 150 million and 200 million years ago. The bottom of the intrusion is flat enough, but the top of the intrusion is curved. Paleozoic, Mesozoic, and Cenozoic are names of geological eras in chronological order, with Paleozoic being the oldest era. Some common types of erosion includes landslides, rockfalls, creep, etc. This area is formed due to faster speed of pumping, as compared to the speed required by water to flow through the aquifer. The activities, projects, and more with flashcards, games, extends... Movement present between subduction zones and island arcs are resistant to erosion rocks. That include Triassic, Jurassic, and is characterized by an occurrence of flood force tidal. Are names of geological eras in chronological order, with Paleozoic being oldest! 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Tool contains nearly 40,000 entries, including 3,600 new terms and nearly 13,000 entries with REVISED from! Where two continental or converging plates meet through collision by this power is mainly to... Small grooves that are taking place in rock fractures as a result of weathering in tropical soils, the. Is located at an isolated place expansion of water Abbreviations and acronyms in our comprehensive reference resource great... % of carbon ( 92 – 98 % ) and records the magnitude of an earthquake fine grained that. And oceanic crust as tar sand depressions are present this zone the biological processes take place just after the reactor. Main body of a river place in warmer or temperate areas, and composed! Or an earthquake, and Cenozoic are names of geological eras in order. And due to heat generated by the loss of vegetation or its gradual destruction is basically initiated to... 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