- published: 02 Sep 2015
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In geology, a vein is a distinct sheetlike body of crystallized minerals within a rock. Veins form when mineral constituents carried by an aqueous solution within the rock mass are deposited through precipitation. The hydraulic flow involved is usually due to hydrothermal circulation.
Veins are classically thought of as being the result of growth of crystals on the walls of planar fractures in rocks, with the crystal growth occurring normal to the walls of the cavity, and the crystal protruding into open space. This certainly is the method for the formation of some veins. However, it is rare in geology for significant open space to remain open in large volumes of rock, especially several kilometers below the surface. Thus, there are two main mechanisms considered likely for the formation of veins: open-space filling and crack-seal growth.
Open space filling is the hallmark of epithermal vein systems, such as a stockwork, in greisens or in certain skarn environments. For open space filling to take effect, the confining pressure is generally considered to be below 0.5 GPa, or less than 3-5 kilometers. Veins formed in this way may exhibit a colloform, agate-like habit, of sequential selvages of minerals which radiate out from nucleation points on the vein walls and appear to fill up the available open space. Often evidence of fluid boiling is present. Vugs, cavities and geodes are all examples of open-space filling phenomena in hydrothermal systems.
In the circulatory system, veins (from the Latin vena) are blood vessels that carry blood toward the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart. In contrast to veins, arteries carry blood away from the heart. Veins are less muscular than arteries and are often closer to the skin. There are valves in most veins to prevent backflow.
In general, veins function to return deoxygenated blood to the heart, and are essentially tubes that collapse when their lumens are not filled with blood. The thick outermost layer of a vein is made of connective tissue, called tunica adventitia or tunica externa. There is a middle layer bands of smooth muscle called tunica media, which are, in general, much thinner than those of arteries, as veins do not function primarily in a contractile manner and are not subject to the high pressures of systole, as arteries are. The interior is lined with endothelial cells called tunica intima. The precise location of veins varies much more from person to person than that of arteries. Veins often display a lot of anatomical variation compared with arteries within a species and between species.
Geology (from the Greek γῆ, gē, i.e. "earth" and -λoγία, -logia, i.e. "study of, discourse") is an earth science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which they change. Geology can also refer generally to the study of the solid features of any celestial body (such as the geology of the Moon or Mars).
Geology gives insight into the history of the Earth by providing the primary evidence for plate tectonics, the evolutionary history of life, and past climates. Geology is important for mineral and hydrocarbon exploration and exploitation, evaluating water resources, understanding of natural hazards, the remediation of environmental problems, and for providing insights into past climate change. Geology also plays a role in geotechnical engineering and is a major academic discipline.
The majority of geological data comes from research on solid Earth materials. These typically fall into one of two categories: rock and unconsolidated material.
In geology, a "vein" is a distinct sheetlike body of crystallized minerals within a rock. Veins form when mineral constituents carried by an aqueous solution within the rock mass are deposited through precipitation. The hydraulic flow involved is usually due to hydrothermal circulation. Veins are classically thought of as being the result of growth of crystals on the walls of planar fractures in rocks, with the crystal growth occurring normal to the walls of the cavity, and the crystal protruding into open space. This certainly is the method for the formation of some veins. However, it is rare in geology for significant open space to remain open in large volumes of rock, especially several kilometers below the surface. Thus, there are two main mechanisms considered likely for the forma...
In this short 10 minute webinar, Cath Pitman, AMC Senior Geologist, discusses the importance of understanding the risks associated with the modelling and estimation of narrow veins and what measures should be taken to mitigate those risks. For more great webinars vist our website www.amcconsultants.com
Part one of a brief introduction to joints, veins, plumose structures, joint arrays, joint sets, joint systems, exfoliation, sheeting joints, columnar jointing and other various terminology and morphologies associated with jointing.
Part two of a brief introduction to joints, veins, plumose structures, joint arrays, joint sets, joint systems, exfoliation, sheeting joints, columnar jointing and other various terminology and morphologies associated with jointing.
Curt Stager on electric banjo at Paul Smith's College Open Mic September 12, 2013.
This is part one of four video segments on joint systems as defined by regional morphology. These systems include fault-related jointing, orogenic forelands and hydraulic fracturing, orogenic conjugate joint systems and theories, orthogonal joint systems and theories, mineral vein fill morphology and growth characteristics.
This is part four of four video segments on joint systems as defined by regional morphology. These systems include fault-related jointing, orogenic forelands and hydraulic fracturing, orogenic conjugate joint systems and theories, orthogonal joint systems and theories, mineral vein fill morphology and growth characteristics.
Yale Simpson, co-chairman of Extorre, explains what a vein is and how they are formed. From Wikipedia: A vein is a distinct sheetlike body of crystallized minerals within a rock. Veins form when mineral constituents carried by an aqueous solution within the rock mass are deposited through precipitation. The hydraulic flow involved is usually due to hydrothermal circulation. Veins are classically thought of as being the result of growth of crystals on the walls of planar fractures in rocks, with the crystal growth occurring normal to the walls of the cavity, and the crystal protruding into open space. This certainly is the method for the formation of some veins. However, it is rare in geology for significant open space to remain open in large volumes of rock, especially several kilometers ...
This is part two of four video segments on joint systems as defined by regional morphology. These systems include fault-related jointing, orogenic forelands and hydraulic fracturing, orogenic conjugate joint systems and theories, orthogonal joint systems and theories, mineral vein fill morphology and growth characteristics.
This is part three of four video segments on joint systems as defined by regional morphology. These systems include fault-related jointing, orogenic forelands and hydraulic fracturing, orogenic conjugate joint systems and theories, orthogonal joint systems and theories, mineral vein fill morphology and growth characteristics.
Rocks & Gold - How rocks tell you where to find gold. For more of my gold finding strategy take a look at the "20-20 Prospecting report" - Click here for 20/20 info - http://goo.gl/BeAi6m Also take a look at my recent gold prospector's hangout on "Mining Gold Traps" - https://www.youtube.com/watch?v=DT67xZU1xnA Prospector Jess from http://hunting4gold.com shows how rocks and gold clues go together. The story rocks tell about where to find gold using rock and mineral evidence. Just what you are looking for. What is the nature of the rocks that surround gold bearing placer deposits? Watch to get some ideas about how to find gold. Good Prospecting! Prospector Jess
A review of basic geological methods for studying and exploring for ore deposits. The lecture was presented at The University of Western Australian in October 2014 to First Year Geology students, but should be of interest to all undergrads and postgrads.
Veins of Gold- Story of Gold Miners, Documentary watch more documentary films https://www.youtube.com/channel/UCetPYpHqgk9_wj0T7g5Z4SA
The Wayside mine is located on the north side of Carpenter Lake at latitude 50° 52' 30", longitude 122° 49' 40", 3.2 kilometres north of Gold Bridge (Figure 9a). Access to the property is by bush roads that connect directly to Highway 40 and the Gun Lake road. The property and mine site was visited repeatedly by the writer and crew between 1986 and 1988. The geology of the property was done together with a magnetometer survey and logging of 20 drill cores provided by Chevron Minerals Limited. The history of the Wayside property has been outlined by Cairnes (1937), Kelly (1972) and McAllister et al. (1988). Details of the periods of active exploration and development from 1906 to 1937, 1946 to 1953 and 1971 to 1988 are given in the Minister of Mines Annual Reports and subsequent governmen...
The former Emancipation mine is located 1 kilometre west of the Coquihalla River, between Fifteen Mile and Ladner creeks. Hope located approximately 15 kilometres to the southwest. The Emancipation mine was developed by five adits (adits 1-4 and A) concentrated along a series of gold-bearing quartz ±carbonate veins that cut the Spider Peak Formation. These veins were the principal ore source of the mine. However, two of the lower workings (adits 3 and 4) were driven on a talc-bearing zone within the Hozameen fault that was apparently barren. In 1933, a drift on the No. 4 level intersected a 3.35-metre wide vein directly beneath the ore zone in the No. 2 winze. The central part contained abundant sulphides and a chip sample across 2.44 metres yielded 13.71 grams per tonne gold and 3.43 gr...
Ore Deposits -- Origin and Processes Host; Dr. David Pearson. Ore Deposits - Lesson 21 - Part 1 of 6 •Ore definition •Finding ore deposits •Instruments of early prospectors •Igneous intrusions •Concentrations of ore •Crystallization of magmas •How are veins produced Ore Deposits - Lesson 21 - Part 2 of 6 •Crystallization of magmas •How are veins produced •Secondary intrusions -- effects of the surrounding rock •Yellowknife Giant Mine •Refined, pouring gold bricks •Yellowknife gold deposit -- vein type •Young Sulphides deposit occur in subduction zones Ore Deposits - Lesson 21 - Part 3 of 6 Host; Dr David Pearson •Ancient subduction zone, ie. Andes mountains •Andes Mountains mineral ore deposit •Geological exploration in Canada early 70's •Geophysical equipment to detect ore deposits i...
Part 4 of Andrew Jackson's informative series on ore deposits for those interested in economic geology.
santafebotanicalgarden.org - Ortiz Mountains Educational Preserve - Discusses the geologic setting of the Ortiz Mountains and examine outcrops of pyroclastic rocks that formed in the 25-30 million year-old Dolores Gulch volcanic vent, and gold-bearing quartzite at the Florencio prospect along its margin. At the Old Ortiz Mine we can observe (but not enter) one of the earliest hard-rock mining efforts in the western United States, and discuss the 1970s-80s-era mining at Cunningham Hill, about 1 mile east of the Old Ortiz Mine. At the Loop Trail we'll ponder the relationship of the massive augite-monzonite (a type of granite) stock to the volcanic rocks.