The Yamato 691 (abbreviated Y-691) is the 4.5 billion year old
chondrite meteorite discovered by members of the
Japanese Antarctic Research Expedition
The refers to a series of Japanese Antarctic expeditions for scientific research.
The first JARE expedition was launched in 1957 to coordinate with the International Geophysical Year. This was the team which left 15 dogs, including Taro and Ji ...
on the
blue ice field of the
Queen Fabiola Mountains
Queen Fabiola Mountains is a group of mountains in Antarctica, long, consisting mainly of seven small massifs which trend north–south, forming a partial barrier to the flow of inland ice. The mountains stand in isolation about southwest of th ...
(Yamato Mountains) in
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...
, on December 21, 1969.
History
Yamato 691 was one among 9 meteorite specimens identified by the Japanese Expedition Team in 1969. It was later studied at the
Max Planck Institute for Chemistry
The Max Planck Institute for Chemistry (Otto Hahn Institute; german: Max Planck Institut für Chemie - Otto Hahn Institut) is a non-university research institute under the auspices of the Max Planck Society (German: Max-Planck-Gesellschaft) in Ma ...
,
Mainz, Germany
Mainz () is the capital and largest city of Rhineland-Palatinate, Germany.
Mainz is on the left bank of the Rhine, opposite to the place that the Main (river), Main joins the Rhine. Downstream of the confluence, the Rhine flows to the north-we ...
.
In April 2011, NASA and co-researchers from the United States, South Korea and Japan have found a new mineral named "
Wassonite" in Yamato 691.
Composition and classification
This meteorite is a stony
enstatite chondrite. Minerals reported from the meteorite include:
*
Troilite
*
Spinel
Spinel () is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula in the cubic crystal system. Its name comes from the Latin word , which means ''spine'' in reference to its pointed crystals.
Properties
S ...
*
Augite
Augite is a common rock-forming pyroxene mineral with formula . The crystals are monoclinic and prismatic. Augite has two prominent cleavages, meeting at angles near 90 degrees.
Characteristics
Augite is a solid solution in the pyroxene group. ...
*
Diopside
*
Enstatite
Enstatite is a mineral; the magnesium endmember of the pyroxene silicate mineral series enstatite (MgSiO3) – ferrosilite (FeSiO3). The magnesium rich members of the solid solution series are common rock-forming minerals found in igneous and m ...
*
Pigeonite
*
Albite
Albite is a plagioclase feldspar mineral. It is the sodium endmember of the plagioclase solid solution series. It represents a plagioclase with less than 10% anorthite content. The pure albite endmember has the formula . It is a tectosilicate. I ...
*
Nepheline
Nepheline, also called nephelite (), is a rock-forming mineral in the feldspathoid groupa silica-undersaturated aluminosilicate, Na3 K Al4 Si4 O16, that occurs in intrusive and volcanic rocks with low silica, and in their associated pegmatites ...
*
Iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
*
Olivine
The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickl ...
*
Wassonite - discovered in April, 2011
See also
*
Glossary of meteoritics
This is a glossary of terms used in meteoritics, the science of meteorites.
#
* 2 Pallas – an asteroid from the asteroid belt and one of the likely parent bodies of the CR meteorites.
* 4 Vesta – second-largest asteroid in the asteroid b ...
References
External links
Mindat.orgPetrochemical study of the Yamato-691 enstatite chondrite (EH3) II: Descriptions and mineral compositions of unusual silicate-inclusions(1988)
Trace element composition and distribution of Yamato-691, an unequilibrated enstatite chondrites(1988)
{{Meteorites by name
Meteorites found in Antarctica