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Hot Dry Rock Geothermal Energy
Hot dry rock (HDR) is an extremely abundant source of geothermal energy that is difficult to access. A vast store of thermal energy is contained within hot – but essentially dry and impervious crystalline basement rocks found almost everywhere deep beneath Earth's surface. A concept for the extraction of useful amounts of geothermal energy from HDR originated at the Los Alamos National Laboratory in 1970, and Laboratory researchers were awarded a U.S. patent covering it. This technology has been tested extensively with multiple deep wells drilled in several field areas around world including the USA, Japan, Australia, France, and the UK and investment of billions of research funds. It continues to be the focus along with a related technique called EGS for sizable government-led research studies involving costly deep drilling and rock studies. Thermal energy has been recovered in reasonably sustainable tests over periods of years and in some cases electrical power generation was also achieved. However no commercial projects are ongoing or likely due to the high cost and limited capacity of the engineered reservoirs, associated wells, and pumping systems. Commonly tests have opened just one or more fractures such that the reservoir surface heat exchange areas are limited. For this technology to successfully compete with other energy sources, drilling costs would have to drop drastically or new approaches that result in much more extensive, complex, and higher rate flow paths through actual fracture networks would have to be established. The enthusiasim evident here on Wikipedia and in the research community is justified by the vast extent of the energy supply and the low environmental impact of the method however significant breakthroughs will be required to make this a commercial energy resource.
  • 6.4K
  • 30 Oct 2022
Topic Review
Southern European People
Southern European people are a pan-ethnic group, or multi-ethnic regional grouping, and the inhabitants of Southern Europe. South or Southern Europeans can usually trace back full or partial heritage to Greece, Italy, Spain , Portugal, as well as nations bordering with, or ethnoculturally related to, the region. As the pan-ethnic group is also culturally defined, rather than exclusively a geographical category, it often includes peoples inhabiting areas that are, at times, considered outside of the region. This can include people with heritage from Southern France, the Mediterranean islands of Corsica (also part of France ), Malta and Cyprus (geographically part of West Asia), Southeastern Europe's Albania and European Turkey. There are also descriptions of Southern Europeans which include ancestry from other nations in Southeast Europe, and countries of the South Slavs, particularly in diasporic identification. As Slavs, they are also often identified as Eastern Europeans. There is a large Southern European diaspora, with significant concentrations in the United Kingdom, North America (Southern European Americans and Canadians), and Southern European Australians in Oceania. Other subgroups of Europeans include Eastern European people and Northwestern European people.
  • 5.9K
  • 29 Sep 2022
Topic Review
Indian Remote Sensing Programme
India's remote sensing program was developed with the idea of applying space technologies for the benefit of human kind and the development of the country. The program involved the development of three principal capabilities. The first was to design, build and launch satellites to a sun synchronous orbit. The second was to establish and operate ground stations for spacecraft control, data transfer along with data processing and archival. The third was to use the data obtained for various applications on the ground.
  • 5.5K
  • 17 Nov 2022
Topic Review
History of Geography
This article explores the history of geography.
  • 5.5K
  • 20 Oct 2022
Topic Review
Geography of Middle-Earth
The geography of Middle-earth encompasses the physical, political, and moral geography of J. R. R. Tolkien's fictional world of Middle-earth, strictly a continent on the planet of Arda but widely taken to mean the physical world, and Eä, all of creation, as well as all of his writings about it. Arda was created as a flat world, incorporating a Western continent, Aman, which became the home of the godlike Valar, as well as Middle-earth. At the end of the First Age, the Western part of Middle-earth, Beleriand, was drowned in the War of Wrath. In the Second Age, a large island, Númenor, was created in the Great Sea, Belegaer, between Aman and Middle-earth; it was destroyed in a cataclysm at the end of the Second Age, in which Arda was remade as a spherical world, and Aman was removed so that Men could not reach it. In The Lord of the Rings, Middle-earth at the end of the Third Age is described as having free peoples, namely Men, Hobbits, Elves, and Dwarves in the West, opposed to peoples under the control of the Dark Lord Sauron in the East. Some commentators have seen this as implying a moral geography of Middle-earth.
  • 5.5K
  • 25 Oct 2022
Topic Review
Upper Mantle (Earth)
The upper mantle of the Earth begins just beneath the crust about 35 km (22 mi) and ends at the top of the lower mantle at 670 km (420 mi). Temperatures range from approximately 200 °C (392 °F) at the upper boundary with the crust to approximately 900 °C (1,650 °F) at the boundary with the lower mantle. Upper mantle material which has come up onto the surface is made up of about 55% olivine, 35% pyroxene and 5 to 10% of calcium oxide and aluminum oxide minerals such as plagioclase, spinel or garnet, depending upon depth.
  • 5.4K
  • 29 Sep 2022
Topic Review
Koh-i-Sultan
Koh-i-Sultan is a volcano in Balochistan, Pakistan. It is part of the tectonic belt formed by the collision of India and Asia: specifically, a segment influenced by the subduction of the Arabian plate beneath the Asian plate and forming a volcanic arc which includes the Bazman and Taftan volcanoes in Iran. The volcano consists of three main cones, with heavily eroded craters running west-northwest and surrounded by a number of subsidiary volcanic centres. Its summit is 2,334 metres (7,657 ft) high, and the crater associated with the Miri cone has a smaller crater inside. The volcano is formed by andesite and dacite rocks, with fragmentary rocks prevailing over lava flows. The rocks have typical arc-volcano chemistry and composition, with a progression from andesite to dacite in the eruption products with younger age. Potassium-argon dating has indicated an age range from 5,900,000 to 90,000 years. Subsequent erosion has generated a large debris apron around the base of the volcano and carved rock formations which impressed early explorers; one well-known rock formation is Neza e Sultan. Geothermal activity and the emission of volcanic gases are ongoing, and the volcano has been prospected for the possibility of obtaining geothermal energy. The geothermal activity has resulted in widespread rock alteration and the formation of sulfur deposits, which were mentioned in a 1909 report and later mined. Koh-i-Sultan also has deposits of other minerals.
  • 5.2K
  • 04 Oct 2022
Topic Review
2020–2021 Taal Volcano Eruptions
Taal Volcano in Batangas, Philippines began to erupt on January 12, 2020, when a phreatomagmatic eruption from its main crater spewed ashes over Calabarzon, Metro Manila, and some parts of Central Luzon and Ilocos Region, resulting in the suspension of school classes, work schedules, and flights in the area. The Philippine Institute of Volcanology and Seismology (PHIVOLCS) subsequently issued an Alert Level 4, indicating "that a hazardous explosive eruption is possible within hours to days." Volcanic activity continued into 2021, when smaller eruptions occurred in July 2021.
  • 5.2K
  • 24 Nov 2022
Topic Review
Chalk
Chalk is a soft, white, porous, sedimentary carbonate rock, a form of limestone composed of the mineral calcite. Calcite is an ionic salt called calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite shells (coccoliths) shed from micro-organisms called coccolithophores. Flint (a type of chert) is very common as bands parallel to the bedding or as nodules embedded in chalk. It is probably derived from sponge spicules or other siliceous organisms as water is expelled upwards during compaction. Flint is often deposited around larger fossils such as Echinoidea which may be silicified (i.e. replaced molecule by molecule by flint). Chalk, as seen in Cretaceous deposits of Western Europe, is unusual among sedimentary limestones in the thickness of the beds. Most cliffs of chalk have very few obvious bedding planes unlike most thick sequences of limestone such as the Carboniferous Limestone or the Jurassic oolitic limestones. This may indicate very stable conditions over tens of millions of years. Chalk has greater resistance to weathering and slumping than the clays with which it is usually associated, thus forming tall, steep cliffs where chalk ridges meet the sea. Chalk hills, known as chalk downland, usually form where bands of chalk reach the surface at an angle, so forming a scarp slope. Because chalk is well jointed it can hold a large volume of ground water, providing a natural reservoir that releases water slowly through dry seasons.
  • 5.1K
  • 29 Nov 2022
Topic Review
Iranian Plateau
The Iranian Plateau or the Persian Plateau is a geological feature in Central Asia, South Asia, and Western Asia. It is the part of the Eurasian Plate wedged between the Arabian and Indian plates, situated between the Zagros Mountains to the west, the Caspian Sea and the Kopet Dag to the north, the Armenian Highlands and the Caucasus Mountains in the northwest, the Strait of Hormuz and the Persian Gulf to the south and the Indo-Gangetic Plain to the east in Indian subcontinent. As a historical region, it includes Parthia, Media, Persis, the heartlands of Iran and some of the previous territories of Greater Iran. The Zagros Mountains form the plateau's western boundary, and its eastern slopes may be included in the term. The Encyclopædia Britannica excludes "lowland Khuzestan" explicitly and characterizes Elam as spanning "the region from the Mesopotamian Plain to the Iranian Plateau". From the Caspian in the northwest to Balochistan in the south-east, the Iranian Plateau extends for close to 2,000 km. It encompasses the greater part of Iran, all of Afghanistan, and Pakistan west of the Indus River containing some 3,700,000 square kilometres (1,400,000 sq mi). In spite of being called a "plateau", it is far from flat but contains several mountain ranges, the highest peak being Damavand in the Alborz at 5610 m, and the Dasht-e Lut east of Kerman in Central Iran falling below 300 m.
  • 5.1K
  • 22 Nov 2022
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