Reidite | |
---|---|
General | |
Category | Zircon group |
Formula (repeating unit) | ZrSiO4 |
IMA symbol | Rei [1] |
Strunz classification | 9.AD.45 |
Crystal system | Tetragonal |
Crystal class | Dipyramidal (4/m) H-M symbol: (4/m) |
Space group | I41/a |
Unit cell | a = 4.738, c = 10.506 [Å], Z = 4 |
Identification | |
Formula mass | 183.31 g/mol |
Color | Colorless to white |
Crystal habit | Epitaxial - crystallographic alignment with a precursor mineral, occurs as inclusions in other minerals. |
Cleavage | None |
Fracture | Irregular/uneven |
Tenacity | Brittle |
Mohs scale hardness | 7.5 |
Luster | Adamantine |
Streak | White |
Diaphaneity | Translucent |
Specific gravity | 5.16 |
Optical properties | Uniaxial (+) |
Refractive index | nω=1.64, nε=1.655 |
Birefringence | 0.0150 |
Pleochroism | None |
References | [2] [3] |
Reidite is a rare polymorph of ZrSiO4 created when zircon experiences high pressure and temperature. Reidite is denser than zircon and has the same crystal structure as scheelite. All natural occurrences of reidite are associated with meteorite impact events.
On Earth, reidite has been reported from ten impact structures: the Chesapeake Bay Crater in Virginia; Ries Crater in Germany; Xiuyan Crater in China; Woodleigh Crater in Western Australia; [4] Rock Elm Crater in Wisconsin; [5] Dhala Crater in India; [6] Stac Fada in Scotland; Haughton in Canada; Steen River in Canada, and Rochechouart in France. Reidite has also been found in one lunar meteorite. [7]
Reidite is named after Alan F. Reid, the scientist who first synthesized it during high-pressure experiments in the laboratory in 1969. [8]
Reidite was first discovered in natural samples by B.P. Glass and Shaobin Liu in 2001. [9]
Reidite is formed from zircon above ~30GPa in shock recovery experiments. However, the temperatures generated during meteorite impacts are much higher, and reidite can be formed down to ~9GPa under natural impact conditions. [10] Reidite has been found in lamellar, granular, and dendritic forms within host zircon, typically making up less than 10% of the grain. Reidite from Rochechouart impact structure has also been reported as bladed, wedged, and massive. [11]
Libyan desert glass may show lattice deformation in zircon that is interpreted as evidence of this material having previously contained reidite, and as such constitutes strong evidence for its impact origin. [12]
9.AD.25 | Uvarovite | Ca3Cr2(SiO4)3 |
9.AD.25 | Wadalite | (Ca,Mg)6(Al,Fe3+)4((Si,Al)O4)3O4Cl3 |
9.AD.25 | Holtstamite | Ca3(Al,Mn3+)2(SiO4)2(OH)4 |
9.AD.25 | Kerimasite | Ca3Zr2(SiO4)(Fe3+O4)2 |
9.AD.25 | Toturite | Ca3Sn2(SiO4)(Fe3+O4)2 |
9.AD.25 | Momoiite | (Mn2+,Ca)3V23+(SiO4)3 |
9.AD.25 | Eltyubyuite | Ca12Fe103+Si4O32Cl6 |
9.AD.25 | Hutcheonite | Ca3Ti2(SiAl2)O12 |
9.AD.30 | Coffinite | (U4+,Th)(SiO4)1-x(OH)4x |
9.AD.30 | Hafnon | HfSiO4 |
9.AD.30 | Thorite | (Th,U)SiO4 |
9.AD.30 | Zircon | ZrSiO4 |
9.AD.30 | Stetindite | Ce4+SiO4 |
9.AD.35 | Huttonite | ThSiO4 |
9.AD.35 | Tombarthite-(Y) | Y4(Si,H4)4O12−x(OH)4+2x |
9.AD.40 | Eulytine | Bi4(SiO4)3 |
Zircon is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is ZrSiO4. An empirical formula showing some of the range of substitution in zircon is (Zr1–y, REEy)(SiO4)1–x(OH)4x–y. Zircon precipitates from silicate melts and has relatively high concentrations of high field strength incompatible elements. For example, hafnium is almost always present in quantities ranging from 1 to 4%. The crystal structure of zircon is tetragonal crystal system. The natural color of zircon varies between colorless, yellow-golden, red, brown, blue, and green.
Manicouagan Reservoir is an annular lake in central Quebec, Canada, covering an area of 1,942 km2 (750 sq mi). The lake island in its centre is known as René-Levasseur Island, and its highest point is Mount Babel. The structure was created 214 (±1) million years ago, in the Late Triassic, by the impact of a meteorite 5 km (3 mi) in diameter. The lake and island are clearly seen from space and are sometimes called the "eye of Quebec". The lake has a volume of 137.9 km3 (33.1 cu mi).
Coesite is a form (polymorph) of silicon dioxide (SiO2) that is formed when very high pressure (2–3 gigapascals), and moderately high temperature (700 °C, 1,300 °F), are applied to quartz. Coesite was first synthesized by Loring Coes, Jr., a chemist at the Norton Company, in 1953.
Impactite is rock created or modified by one or more impacts of a meteorite. Impactites are considered metamorphic rock, because their source materials were modified by the heat and pressure of the impact. On Earth, impactites consist primarily of modified terrestrial material, sometimes with pieces of the original meteorite.
Rochechouart impact structure or Rochechouart astrobleme is an impact structure in France. Erosion has over the millions of years mostly destroyed its impact crater, the initial surface expression of the asteroid impact leaving highly deformed bedrock and fragments of the crater's floor as evidence of it.
The Rock Elm Disturbance is an impact crater in Pierce County, Wisconsin, United States, roughly 40 kilometres (25 mi) southwest of Menomonie. The disturbance is named for Rock Elm, Wisconsin, a nearby town.
The Vredefort impact structure is the largest verified impact structure on Earth. The crater, which has since been eroded away, has been estimated at 170–300 kilometres (110–190 mi) across when it was formed. The remaining structure, comprising the deformed underlying bedrock, is located in present-day Free State province of South Africa. It is named after the town of Vredefort, which is near its centre. The structure's central uplift is known as the Vredefort Dome. The impact structure was formed during the Paleoproterozoic Era, 2.023 billion years ago. It is the second-oldest known impact structure on Earth, after Yarrabubba.
The Yarrabubba impact structure is the eroded remnant of an impact crater, situated in the northern Yilgarn Craton near Yarrabubba Station between the towns of Sandstone and Meekatharra, Mid West Western Australia. With an age of 2.229 billion years, it is the oldest known impact structure on Earth.
Meteoritics is the science that deals with meteors, meteorites, and meteoroids. It is closely connected to cosmochemistry, mineralogy and geochemistry. A specialist who studies meteoritics is known as a meteoriticist.
Libyan desert glass or Great Sand Sea glass is an impactite, made mostly of lechatelierite, found in areas in the eastern Sahara, in the deserts of eastern Libya and western Egypt. Fragments of desert glass can be found over areas of tens of square kilometers.
Pseudotachylyte is an extremely fine-grained to glassy, dark, cohesive rock occurring as veins that form through frictional melting and subsequent quenching during earthquakes, large-scale landslides, and impacts events. Chemical composition of pseudotachylyte generally reflects the local bulk chemistry, though may skew to slightly more mafic compositions due to the preferential incorporation of hydrous and ferro-magnesian minerals into the melt phase.
The term iridium anomaly commonly refers to an unusual abundance of the chemical element iridium in a layer of rock strata at the Cretaceous–Paleogene (K–Pg) boundary. The unusually high concentration of a rare metal like iridium is often taken as evidence for an extraterrestrial impact event.
Wadsleyite is an orthorhombic mineral with the formula β-(Mg,Fe)2SiO4. It was first found in nature in the Peace River meteorite from Alberta, Canada. It is formed by a phase transformation from olivine (α-(Mg,Fe)2SiO4) under increasing pressure and eventually transforms into spinel-structured ringwoodite (γ-(Mg,Fe)2SiO4) as pressure increases further. The structure can take up a limited amount of other bivalent cations instead of magnesium, but contrary to the α and γ structures, a β structure with the sum formula Fe2SiO4 is not thermodynamically stable. Its cell parameters are approximately a = 5.7 Å, b = 11.71 Å and c = 8.24 Å.
Shock metamorphism or impact metamorphism describes the effects of shock-wave related deformation and heating during impact events.
Dhala crater is an impact structure formed by an asteroid impact. It is situated near Bhonti village in Pichhore block of Shivpuri district of Madhya Pradesh state in India. It is the largest impact structure in India, and between the Mediterranean and Southeast Asia. The diameter of the structure is estimated at 3 kilometres (1.9 mi), while other sources estimate its diameter to be 11 km diameter. It is the second such structure found in India, after Lonar lake.
Elephant Moraine 79001, also known as EETA 79001, is a Martian meteorite. It was found in Elephant Moraine, in the Antarctic during the 1979–1980 collecting season.
Lunar Sample 14321, better known as "Big Bertha", is a lunar sample containing an embedded Earth-origin meteorite collected on the 1971 Apollo 14 mission. It was found in the Fra Mauro region of the Moon. Big Bertha is the first discovered meteorite from Earth, and the embedded meteorite portion is the oldest known Earth rock. At 8.998 kg (19.84 lb), this breccia rock is the third largest Moon sample returned during the Apollo program, behind Big Muley and Great Scott.
Ludovic Ferrière is a geologist and curator of the meteorite collection and of the impactite collection at the Natural History Museum, Vienna, Austria. He is known for his research on meteorite impact craters.
Diane Seward is a low temperature thermochronologist. She is currently a Teaching Fellow at Victoria University of Wellington and affiliated with GNS Science. Seward's work has predominantly focused on thermochronology applied to basin analysis and tectonic evolution. Her research has also been instrumental in developing dating of volcanic deposit through fission track analysis.