Diabase (pronounced /ˈdaɪəbeɪs/) is a mafic, holocrystalline, igneous rock equivalent to volcanic basalt or plutonic gabbro. Mafic is an adjective describing a Silicate mineral or rock that is rich in magnesium and iron the term was derived by contracting "magnesium" and "ferric" Crystallinity refers to the degree of structural order in a Solid. Igneous rocks (etymology from Latin ignis, fire are rocks formed by solidification of cooled Magma (molten rock Plate tectonics and hotspots Divergent plate boundaries At the Basalt (bəˈsɔːlt ˈbeisɔːlt ˈbæsɔːlt is a common Extrusive Volcanic rock. In Geology, an intrusion is a body of Igneous rock that has Crystallized from molten Magma below the surface of the Earth. Gabbro (ˈɡæbrəʊ is a dark coarse-grained intrusive Igneous rock chemically equivalent to Basalt. Diabase is also called dolerite in many references outside North America^[1][2]. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine grained to aphanitic chilled margins which may contain tachylite (dark mafic glass). Tachylite (also spelled tachylyte is a Vitreous form of Basaltic Volcanic glass.

Diabase normally has a fine, but visible texture of euhedral lath shaped plagioclase crystals (62%) set in a finer matrix of clinopyroxene, typically augite (20-29%), with minor olivine (3% up to 12% in olivine diabase), magnetite (2%) and ilmenite (2%)^[3]. Euhedral Crystals are those that are well-formed with sharp easily-recognized faces A lath is a thin narrow strip of some straight-grained wood or other material including Metal or Gypsum. Plagioclase is a very important series of tectosilicate Minerals within the Feldspar family In Materials science, a crystal is a Solid in which the constituent Atoms Molecules or Ions are packed in a regularly ordered repeating The pyroxenes are a group of important rock-forming Silicate minerals found in many Igneous and metamorphic rocks. Augite is a single chain inosilicate Mineral described chemically as (CaMgFeSiO3 or Calcium Magnesium Iron The Mineral olivine (when gem-quality also called Peridot) is a Magnesium Iron silicate with the formula ( Mg Magnetite is not to be confused with Magnesite or Maghemite. Magnetite is a ferrimagnetic Mineral with chemical Ilmenite is a weakly magnetic titanium-iron oxide Mineral which is iron-black or steel-gray Accessory and alteration minerals include hornblende, biotite, apatite, pyrrhotite, chalcopyrite, serpentine, chlorite, and calcite. A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific Hornblende is a complex inosilicate series of Minerals Hornblende is not a recognized mineral in its own right but the name is used as a general or field term to Biotite is a common phyllosilicate Mineral within the Mica group with the approximate chemical formula K(Mg Fe3AlSi3O10(F Pyrrhotite is an unusual Iron Sulfide mineral with a variable iron content Fe(1-xS (x = 0 to 0 Chalcopyrite (ˌkælkoʊˈpaɪraɪt kal-co-pie-right —"kal" as in " cal endar" "co" as in co de is a Copper The serpentine group describes a group of common rock-forming hydrous Magnesium Iron phyllosilicate (()3 Minerals they The chlorites are a group of phyllosilicate Minerals Chlorites can be described by the following four endmembers based on their chemistry via substitution Calcite is a carbonate mineral and the most stable polymorph of Calcium carbonate ( Ca[[carbon C]] O 3 The texture is termed diabasic and is typical of diabases. This diabasic texture is also termed interstitial^[4]. The feldspar is high in anorthite (as opposed to albite), the calcium end member of the plagioclase Anorthite-Albite solid solution series, most commonly labradorite. Feldspar is the name of a group of rock-forming Minerals which make up as much as 60% of the Earth 's crust. Anorthite is a compositional variety of Plagioclase Feldspar. Albite is a plagioclase Feldspar Mineral. It is the sodium endmember of the Plagioclase Solid solution series Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 Labradorite ((CaNa(AlSi4O8 a Feldspar Mineral, is an intermediate to calcic member of the Plagioclase series

Contents 1 Locations 2 Diabase/dolerite 2.1 Inscription controversy 3 References

Locations

Diabase is usually found in smaller relatively shallow intrusive bodies such as dikes and sills. A dike or dyke in Geology is a type of Sheet intrusion referring to any geologic body that cuts Discordantly ' across planar In Geology, a sill is a tabular Pluton that has intruded between older layers of Sedimentary rock, beds of Volcanic Diabase dikes occur in regions of crustal extension and often occur in dike swarms of hundreds of individual dikes or sills radiating from a single volcanic center. Plate tectonics and hotspots Divergent plate boundaries At the

The Palisades Sill which makes up the New Jersey Palisades on the Hudson River, near New York City, is an example of a diabase sill. The Palisades Sill is a Triassic, 200 Ma Diabase Intrusion. It extends through portions of New York and New Jersey The Palisades, also called the New Jersey Palisades or the Hudson Palisades (some portions are also referred to as Bergen Hill) are a line of steep The Hudson River, called Muh-he-kun-ne-tuk, the Great Mohegan by the Iroquois, or as the Lenape Native Americans called it in Unami The City of New York The dike complexes of the Hebridean Tertiary volcanic province which includes Skye, Rum, Mull, and Arran of western Scotland, the Slieve Gullion region of Ireland, and extends across northern England contains many examples of diabase dike swarms. See also Hebrides (disambiguation The Hebrides (ˈhɛbrɨˌdiːz "HEB-ri-deez" Gaelic: Innse Gall) comprise a widespread and diverse The chuprichondira geological time interval covers roughly the time span between the demise of the non- avian Dinosaurs and beginning of the most recent Ice Age, approximately Scotland ( Gaelic: Alba) is a Country in northwest Europethat occupies the northern third of the island of Great Britain. Slieve Gullion ( Irish: Sliabh Cuilinn) is an extinct volcano in the south of County Armagh in Northern Ireland. Ireland (pronounced /ˈaɾlənd/ Éire) is the third largest island in Europe, and the twentieth-largest island in the world England is a Country which is part of the United Kingdom. Its inhabitants account for more than 83% of the total UK population whilst its mainland Parts of the Deccan Traps of India, formed at the end of the Cretaceous also includes dolerite^[5]. The Deccan Traps are a Large igneous province located on the Deccan Plateau of west-central India (between 17-24N 73-74E and one of the largest Volcanic The Cretaceous (kriːˈteɪʃəs, usually abbreviated 'K' for its German translation "Kreide" is a geologic period and system, reaching from the end of It is also abundant in large parts of Curaçao, an island off the coast of Venezuela. Curaçao (ˈkjuːrəsaʊ in English Dutch: Curaçao, Papiamento: Kòrsou) is an Island in the southern Caribbean Sea, Venezuela (ˌvɛnəˈzweɪlə) officially the Bolivarian Republic of Venezuela (Spanish República Bolivariana de Venezuela) is a country on the

In Western Australia a 200 km long dolerite dyke, the Norseman–Wiluna Belt^[6] is associated with the non-alluvial gold mining area between Norseman and Kalgoolie, which includes the largest gold mine in Australia^[7], the Fimiston Superpit. Western Australia is a state occupying the entire western third of the Australian continent. Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79 Norsemen is used to refer to the group of people as a whole who speak one of the North Germanic languages as their native language For a topic outline on this subject see List of basic Australia topics.

The vast areas of mafic volcanism/plutonism associated with the Jurassic breakup of Gondwanaland in the Southern Hemisphere include many large diabase/dolerite sills and dike swarms. Plutonic theory is the Geologic Theory proposed by James Hutton around the turn of the 19th century that volcanic activity was the source of The Jurassic is a geologic period and system that extends from about Ma (million years ago to  Ma that is from the end of the Triassic to the beginning Gondwana (ɡɒnˈdwɑːnə originally Gondwanaland) was a southern Supercontinent that existed about 500 to 200 Ma ago Southern Hemisphere is the half of a Planet that is South of the Equator —the word hemisphere literally means 'half ball' These include the Karoo dolerites of South Africa, the Ferrar Dolerites of Antarctica, and the largest of these, indeed the most extensive of all dolerite formations worldwide, are found in Tasmania. The Karoo (a Khoisan word of uncertain etymology) is a semi- Desert region of South Africa. The Republic of South Africa (also known by other official names) is a country located at the southern tip of the continent of Africa Tasmania is an Australian island and state of the same name It is located south of the eastern side of the Continent, being separated from it by Bass Here, the volume of magma which intruded into a thin veneer of Permian and Jurassic rocks from multiple feeder sites, over a period of perhaps a million years, may have exceeded 40,000 cubic kilometres^[8]. Magma (Plurals magmas and magmata) is molten rock that sometimes forms beneath the surface of the Earth (or any other Terrestrial planet The Permian is a geologic period and system that extends from 299 CM3 redirects here If you were looking for the 3rd game in the Cooking Mama series abbreviated as CM3 see here. In Tasmania alone dolerite dominates the landscape.

Diabase/dolerite

In non North American usage dolerite is often preferred and diabase is used to refer to an altered dolerite. Dolerite (Greek: doleros, meaning "deceptive") was the name given by Haüy in his 1822 Traité de minéralogie. Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly René Just Haüy (aɥi February 28, 1743 in Saint-Just-en-Chaussée ( Oise) &ndash June 3, 1822 in Paris) was In current geologic usage diabase is preferred.

Inscription controversy

During seven centuries a diabase formation called Runamo was famous in Scandinavia as a runic inscription, until it became the object of a famous scientific controversy in the first half of the 19th century. Runamo is a cracked Dolerite dike that was for centuries held to be a Runic inscription and gave rise to a famous scholarly controversy in the 19th century Terminology and usage As a cultural term "Scandinavia" has no official definition and is subject to usage by those who identify with the culture in question as well The 19th century of the Common Era began on January 1, 1801 and ended on December 31, 1900, according to the Gregorian calendar

References

David Edward Leaman, born in Hobart, Tasmania is an Author, structural geologist, geohydrologist and Geophysicist.

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