Aletai meteorite

Last updated
Aletai
Tian Wai Lai Ke .Yun Shi China Xinjiang Urumqi Welcome you to tour the - panoramio.jpg
The Armanty fragment in front of the Xinjiang Geological and Mineral Museum in Ürümqi.
Type Iron
Structural classification Coarse octahedrite
Group IIIE-an
Composition9.8% Ni, 0.52% Co, 109 ppm Cu, 16.9 ppm Ga, 14.4 ppm As, 1.81 ppm Au, 0.228 ppm Ir [a]
Country China
Region Xinjiang
Coordinates 45°52′16″N90°30′17″E / 45.87111°N 90.50472°E / 45.87111; 90.50472 [a]
Observed fall No
Found date1898 [a]
TKW ~74,500 kg [1]
Strewn field Yes
Aletai (meteorite).jpg
A small fragment of the Aletai meteorite with visible Widmanstätten patterns on display at the Tianjin Natural History Museum.
Commons-logo.svg Related media on Wikimedia Commons

The Aletai meteorite, previously also known as the Armanty meteorite or Xinjiang meteorite, is one of the largest known iron meteorites, classified as a coarse octahedrite in chemical group IIIE-an. [b] In addition to many small fragments, at least five main fragments with a total mass over 74 tonnes have been recovered, the largest weighing about 28 tonnes. [1]

Contents

Among the irons of the Aletai meteorite, three pieces can be distinguished, which apparently occupy at the moment the 5-th, 6-th and 9-th places among the largest meteorites found on Earth. [3] The corresponding strewn field along its long axis is at least 430 km (and presumably even larger). It is by a margin the largest meteorite debris scattering field found on the planet, believed to be due to its unique stone skipping-like trajectory. [4]

Name

For over century after its discovery in 1898, the meteorite was known only from one fragment, and this fragment was assumed to be a single meteorite. Its name was Armanty in the original Russian reports and Western sources, but Xinjiang in Chinese literature. [5] In the early 21st century, with the discovery of other fragments, initially also thought to be separate, unconnected meteorites with their individual names, it finally became clear that they were all most likely part of a once single, larger body. And in 2016 the parent meteorite was named the Aletai meteorite after the Altay Prefecture in Nortern Xinjiang where fragments were found. The prefecture, in turn, was named after the Altai Mountains. Since then when referring generally to the irons, authors should use the name Aletai. When referring to a specific mass, authors should identify it as, for example, the "Armanty mass of Aletai" or the "Akebulake mass of Aletai". The list of recommended mass names for Aletai appears in the table below. [1]

History

The first and the largest fragment, Armanty, was discovered in 1898. In 1965, it was transported to the city of Urumqi and is now located in front of the entrance to the local museum. [6] Until the beginning of the 21st century, this fragment was considered an individual meteorite. In 2004, a second fragment was found about 130 kilometers southeast of the Armanti discovery site during fieldwork by geologist Xiaodong Li, which was dubbed the Ulasitai iron. [7] [6] The third, relatively small mass was purchased from an anonymous finder, with the find supposedly made in April 2005. [8] In 2011, Akebulake and Wuxilike, two other very large fragments were found. [1] [9] And finally, in 2021, another one (WuQilike). In the process of discovering the fragments, comparing their chemical composition and structure, it became clear that they are parts of a once single entity. [1]

Specimens

Known masses of Aletai meteorite [10]
Mass nameYear of discoveryLatitude (N)Longitude (E)LocationMass, kg
Armanty189845°52′16″90°30′17″ 45°52′16″N90°30′17″E / 45.87111°N 90.50472°E / 45.87111; 90.50472 28,000
WuQilike202148°02′17″88°23′03″ 48°02′17″N88°23′03″E / 48.03806°N 88.38417°E / 48.03806; 88.38417 23,000
Akebulake201148°06′15″88°16′34″ 48°06′15″N88°16′34″E / 48.10417°N 88.27611°E / 48.10417; 88.27611 18,000
Wuxilike [c] 201148°03′08″88°22′19″ 48°03′08″N88°22′19″E / 48.05222°N 88.37194°E / 48.05222; 88.37194 5,000
Ulasitai [d] 200444°57′24″91°24′09″ 44°57′24″N91°24′09″E / 44.95667°N 91.40250°E / 44.95667; 91.40250 430
Xinjiang (b) [e] 200547°58′42″88°13′06″ 47°58′42″N88°13′06″E / 47.97833°N 88.21833°E / 47.97833; 88.21833 35
(unnamed) [f]  ?48°04′42″ [g] 88°19′27″ [g] 48°04′42″N88°19′27″E / 48.07833°N 88.32417°E / 48.07833; 88.32417 [g] 15
Total:74,480

Composition and classification

It is an iron meteorite (coarse octahedrite) and belongs to the very rare chemical group IIIE-an (i.e. chemical group IIIE with anomalous properties [2] ). At present, only two meteorites fall into this group. [11] Different from other IIIE members, Aletai irons are characterized by higher Au and Co contents and unexcepted Ir contents that do not fall on extrapolation of the Au-Ir trend of the other IIIE irons. Overall, by combining geochemical data with petrologic observations, we concur with the conclusion of Meteoritical Bulletin 105 that Aletai is an anomalous IIIE iron. The composition of Aletai irons is so unique that no other samples in the world meteorite collection are comparable. [4] The Ulasitai meteorite consists mainly of kamacite (76 vol%), taenite (10 vol%), and plessite (10.6 vol%) with less abundant schreibersite (3.4 vol%) and minor troilite, cohenite, and daubréelite. The Widmanstätten pattern has bandwidths of kamacite in a range of 0.9–1.8 mm and an average of 1.2 ± 0.2 mm. Schreibersite mainly occurs as coarse laths with sizes up to 1.2 mm wide and 8.9 mm long observed on the etched polished sections. Small grains of schreibersite (normally <20 μm thin) were also found along grain boundaries of kamacite, taenite, and sulfides, and inside of plessite. [6] Akebulake and WuQilike in turn consist mainly of kamacite (~80 to 83 volume %), taenite (~10 to 11 volume %), plessite (~3 to 8 volume %), and schreibersite (~2 to 3 volume %) with minor troilite, haxonite, and daubréelite. Kamacite plates display a medium-sized Widmanstätten pattern with a bandwidth of ~1 to 1.4 mm. Similarity of chemical composition and internal structure and unique ratio of rare elements strongly suggest that all the Aletai masses are from the same fall event. [4]

See also

Notes

  1. 1 2 3 Data for Armanty fragment. [1]
  2. ↑ An iron meteorite belonging to chemical group IIIE with anomalous properties. [2]
  3. ↑ Was given the provisional name Xinjiang 008. [1]
  4. ↑ Published in Meteoritical Bulletin 90 as a distinct meteorite. [1]
  5. ↑ Published as a distinct IIIAB iron in Meteoritical Bulletin 104. [1]
  6. ↑ Found in the Xiaodonggou region close to the place where Wuxilike and Akebulake were found. [1]
  7. 1 2 3 Unnamed 15 kg of mass that was found in the Xiaodonggou area close to Wuxilike and Akebulake without precise latitude and longitude. Its coordinates are given for the middle between Wuxilike and Akebulake. [4]

Related Research Articles

<span class="mw-page-title-main">Kamacite</span> Alloy of iron and nickel found in meteorites

Kamacite is an alloy of iron and nickel, which is found on Earth only in meteorites. According to the International Mineralogical Association (IMA) it is considered a proper nickel-rich variety of the mineral native iron. The proportion iron:nickel is between 90%:10% and 95%:5%; small quantities of other elements, such as cobalt or carbon may also be present. The mineral has a metallic luster, is gray and has no clear cleavage although its crystal structure is isometric-hexoctahedral. Its density is about 8 g/cm3 and its hardness is 4 on the Mohs scale. It is also sometimes called balkeneisen.

<span class="mw-page-title-main">Octahedrite</span> Structural class of iron meteorites

Octahedrites are the most common structural class of iron meteorites. The structures occur because the meteoric iron has a certain nickel concentration that leads to the exsolution of kamacite out of taenite while cooling.

<span class="mw-page-title-main">Sikhote-Alin meteorite</span> 1947 meteorite impact in southeastern Russia

In southeastern Russia, an iron meteorite fell on the Sikhote-Alin Mountains in 1947. Large iron meteorite falls have been witnessed, and fragments have been recovered, but never before in recorded history has a fall of this magnitude occurred. An estimated 23 tonnes of fragments survived the fiery passage through the atmosphere and reached the Earth.

<span class="mw-page-title-main">Widmanstätten pattern</span> Crystal patterns found in some meteorites

Widmanstätten patterns, also known as Thomson structures, are figures of long phases of nickel–iron, found in the octahedrite shapes of iron meteorite crystals and some pallasites.

<span class="mw-page-title-main">Canyon Diablo (meteorite)</span> Iron meteorite from Meteor Crater used as sulfur isotopic reference material

The Canyon Diablo meteorite refers to the many fragments of the asteroid that created Meteor Crater, Arizona, United States. Meteorites have been found around the crater rim, and are named for nearby Canyon Diablo, which lies about three to four miles west of the crater.

<span class="mw-page-title-main">Meteoric iron</span> Iron originating from a meteorite rather than from the Earth since formation

Meteoric iron, sometimes meteoritic iron, is a native metal and early-universe protoplanetary-disk remnant found in meteorites and made from the elements iron and nickel, mainly in the form of the mineral phases kamacite and taenite. Meteoric iron makes up the bulk of iron meteorites but is also found in other meteorites. Apart from minor amounts of telluric iron, meteoric iron is the only naturally occurring native metal of the element iron on the Earth's surface.

<span class="mw-page-title-main">Ataxite</span> Structural class of iron meteorites

Ataxites are a structural class of iron meteorites with a high nickel content and show no Widmanstätten patterns upon etching.

<span class="mw-page-title-main">Taenite</span> Alloy of iron and nickel found in meteorites

Taenite is a mineral found naturally on Earth mostly in iron meteorites. It is an alloy of iron and nickel, with a chemical formula of Fe,Ni and nickel proportions of 20% up to 65%.

<span class="mw-page-title-main">Plessite</span> Alloy of iron and nickel found in meteorites

Plessite is a meteorite texture consisting of a fine-grained mixture of the minerals kamacite and taenite found in the octahedrite iron meteorites. It occurs in gaps between the larger bands of kamacite and taenite which form Widmanstätten patterns.

<span class="mw-page-title-main">Iron meteorite</span> Meteorite composed of iron-nickel alloy called meteoric iron

Iron meteorites, also called siderites or ferrous meteorites, are a type of meteorite that consist overwhelmingly of an iron–nickel alloy known as meteoric iron that usually consists of two mineral phases: kamacite and taenite. Most iron meteorites originate from cores of planetesimals, with the exception of the IIE iron meteorite group.

<span class="mw-page-title-main">Hadley Rille meteorite</span> Meteorite on the Moon

The Hadley Rille meteorite was a meteorite discovered on the Moon at coordinates 26° 26' 0" N, 3° 39' 20" E, or Station 9A, during the Apollo 15 mission in 1971. It was the second meteorite to be discovered on a Solar System body other than the Earth. The first was the Bench Crater meteorite, discovered in 1969 during the Apollo 12 mission.

<span class="mw-page-title-main">Seymchan (meteorite)</span>

Seymchan is a pallasite meteorite found in the dry bed of the river Hekandue, a left tributary of river Yasachnaya in the Magadan district, Russia, near the settlement of Seymchan, in June 1967.

Lac Dodon is an iron meteorite discovered by Roland Octerneau of Montreal on rural private property near Lac Dodon, Saint-Calixte, Quebec.

<span class="mw-page-title-main">IAB meteorite</span> Group of iron meteorites

IAB meteorites are a group of iron meteorites according to their overall composition and a group of primitive achondrites because of silicate inclusions that show a strong affinity to winonaites and chondrites.

<span class="mw-page-title-main">Daubréelite</span> Sulfide mineral

Daubréelite is a rare sulfide mineral. It crystallizes with cubic symmetry and has chemical composition of Fe2+Cr3+2S4. It usually occurs as black platy aggregates.

The Santa Vitoria do Palmar meteorite was found near the city of Santa Vitoria do Palmar in Brazil in 2003 and 2004.

<span class="mw-page-title-main">Stony-iron meteorite</span> Meteorites that consist of nearly equal parts of meteoric iron and silicates

Stony-iron meteorites or siderolites are meteorites that consist of nearly equal parts of meteoric iron and silicates. This distinguishes them from the stony meteorites, that are mostly silicates, and the iron meteorites, that are mostly meteoric iron.

This is a glossary of terms used in meteoritics, the science of meteorites.

<span class="mw-page-title-main">IIAB meteorites</span> Type of iron meteorite

IIAB meteorites are a group of iron meteorites. Their structural classification ranges from hexahedrites to octahedrites. IIABs have the lowest concentration of nickel of all iron meteorite groups. Most iron meteorites are derived from the metallic planetary cores of their respective parent bodies, but in the case of the IIABs the metallic magma separated to form not only this meteorite group but also the IIG group.

<span class="mw-page-title-main">Carlsbergite</span> Chromium nitride mineral found in meteorites

Carlsbergite is a nitride mineral that has the chemical formula CrN, or chromium nitride.

References

  1. 1 2 3 4 5 6 7 8 9 10 "Aletai". Meteoritical Bulletin Database. The Meteoritical Society. 2024-09-05. Retrieved 2024-09-05.
  2. 1 2 "Recommended classifications". Meteoritical Bulletin Database. The Meteoritical Society . Retrieved 2024-09-05.
  3. ↑ "Aletai Meteorite. Partial Slice of Aletai (Armanty) — A Most Notable Iron Meteorite". Sotheby's . December 2021. Retrieved 2024-09-05.
  4. 1 2 3 4 Li, Ye; et al. (24 June 2022). "A unique stone skipping–like trajectory of asteroid Aletai". Science Advances . 8 (25). doi:10.1126/sciadv.abm8890. PMC   9232108 . Retrieved 2024-09-05.
  5. ↑ Wasson, John T.; Ouyang, Xinwei; Wang, Daode (December 1988). "Compositional Study of a Suite of Samples from the 28-t Armanty (Xinjiang) Iron Meteorite" . Meteoritics . 23 (4): 365–369. doi:10.1111/j.1945-5100.1988.tb00924.x.
  6. 1 2 3 Xu, Lin; Miao, Bingkui; Lin, Yangting; Ouyang, Ziyuan (August 2008). "Ulasitai: A new iron meteorite likely paired with Armanty (IIIE)". Meteoritics & Planetary Science . 43 (8): 1263–1273. doi:10.1111/j.1945-5100.2008.tb00696.x.
  7. ↑ "Ulasitai". Meteoritical Bulletin Database. The Meteoritical Society. 2024-09-05. Retrieved 2024-09-05.
  8. ↑ "Xinjiang (b)". Meteoritical Bulletin Database. The Meteoritical Society. 2024-09-05. Retrieved 2024-09-05.
  9. ↑ Zhou, Y. Y.; Xu, W. B.; Hu, B.; Luo, H. W. (November 2021). "Microstructure, Cooling History and Its Quantitative Modelling of Wuxilike Iron Meteorite". Acta Astronomica Sinica (in Chinese). 62 (6) 60. Bibcode:2021AcASn..62...60Z.
  10. ↑ "List of Strewnfield Members of Aletai". Meteoritical Bulletin Database. Lunar and Planetary Institute. 2021-10-03. Retrieved 2024-09-08.
  11. ↑ "Meteorites with types that are exactly "Iron, IIIE-an"". Meteoritical Bulletin Database. The Meteoritical Society. 2024-09-05. Retrieved 2024-09-05.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.