Tissintit

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Tissintit
General and classification
other names

Calcium Eskola Component, Ca-Eskola, IMA 2013-027

chemical formula (Ca, Na, □) AlSi 2 O 6
Mineral class
(and possibly department) 		Silicates and Germanates
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group C 2 / c (No. 15)Template: room group / 15
Lattice parameters a  = 9.21 (17)  Å ; b  = 9.09 (4) Å; c  = 5.20 (2) Å
α  = 90 °; β  = 109.6 (9) °°; γ  = 90 °
Formula units Z  = 4
Physical Properties
Mohs hardness not determined
Density (g / cm 3 ) natural: 3.32 (calculated)
Cleavage not determined
Break ; Tenacity not determined
colour not determined
Line color not determined
transparency not determined
shine not determined
radioactivity -
magnetism -
Crystal optics
Refractive index n  = not determined
Birefringence δ = not determined
Optical character not determined
Axis angle 2V = not determined

The mineral Tissintit is a very rare chain silicate from the pyroxene group with the idealized chemical composition (Ca, Na, □) AlSi 2 O 6 .

Tissintite crystallizes with monoclinic symmetry and forms crystals of a few µm in size.

Tissintite is formed from maskelynite during impact metamorphosis as a result of meteorite impacts. The type locality is the Tissint Martian meteorite , a shergottite that was found southeast of Tata in Morocco .

Etymology and history

The story of the discovery of Tissintite probably began about a million years ago with a minor meteorite impact on Mars . For a brief moment of 10-20 ms, ~ 2500 ° C and a pressure of at least 30 GPa were reached. The force of the impact was enough to throw rocks from Mars into space.

One of these boulders crossed earth's orbit after ~ 1,000,000 years and hit Tissint southeast of Tata in Morocco on June 18, 2011 at around 2 a.m. It was the 5th Martian meteorite whose impact was observed. Nevertheless, it took until the end of December for nomads to find the point of impact and recover fragments of the meteorite. Soon after, the fragments were trading at prices of up to US $ 1,000 / g. At the beginning of January 2012, a nomad finally contacted Professor Ibhi Abderrahmane from Ibnou Zohr University in Agadir , who initiated a systematic search.

During the nanomineralogical investigation of a fragment of this meteorite, the working group led by Ci Ma from the California Institute of Technology in Pasadena discovered the high-pressure minerals ahrensite and the pyroxene Tissintite, which they named after the place Tissint in Morocco, in the vicinity of the place also after the place named Tissint meteorite went down.

Tissintite is the first void-containing pyroxene to be recognized as a mineral by the International Mineralogical Association (IMA). 12 years earlier, CA Goodrich from the Max Planck Institute for Chemistry in Mainz and GE Harlow from the American Museum of Natural History in New York described a chrome eskola pyroxene whose M2 position is only half occupied by magnesium. It has the composition (□ 0.5 Mg 0.29–0.45 Fe 0.06–0.19 Ca 0.01 ) (Cr 0.78–0.90 Al 0.08–0.21 Ti 0, 01 ) (Si 1.98 Al 0.02 ) O 6 and occurs together with Uwarowit -containing Knorringite in the meteorite LEW88774. A full description and recognition as a mineral is still pending.

The Finnish geologist Pentti Eskola found the first indications of pyroxenes with incompletely occupied cation positions of terrestrial origin in Norwegian eclogites in 1921 when he described the adhesions of omphacite with plagioclase. He interpreted it as a conversion product of a pyroxene stable at high pressure, from which a plagioplasmic component dissolved in the pyroxene separates when the pressure drops. DE Vogel described comparable clinopyroxen plagioclase symplektites in 1966 in eclogites from northwest Spain. For the composition of this high pressure pyroxene, Vogel calculated an excess of silicon relative to the other cations or a deficit of calcium, which he found as a mixed crystal with the hypothetical pyroxene [M2] (Ca 0.5 □ 0.5 ) [M1] Al [T ] Si 2 O 6 declared. In the following literature, this mixed crystal component is referred to as calcium eskola component or Ca eskola for short. Pyroxenes with up to 18 mol% of the Ca-Eskola component or their breakdown products have been found in ultra-high pressure rocks worldwide.

Experimental investigations on non-stoichiometrically composed pyroxenes with incompletely occupied cation positions have existed since the 1970s. Bernard J. Wood and CMB Henderson from the University of Manchester synthesized pyroxenes with ~ 10 mol% Ca-Eskola component at 25–32 kbar and found that the density of these pyroxenes is comparatively high despite vacancies. You observe an increase in the vacancy content with increasing pressure.

Masato Okui's group from Nihon University in Tokyo demonstrated in 1998 that void-rich pyroxenes are not necessarily high-pressure minerals. At 1 bar pressure they synthesized a diopside kushiroite mixed crystal with a very high proportion of the Ca-Eskola component of ~ 32 mol%.

In 2007, Jürgen Konzett and colleagues investigated how the Ca-Eskola content of pyroxenes depends on the educational conditions. For eclogitic rock compositions they found a high dependence of the Ca-Eskola content on the aluminum and sodium content as well as the temperature. They found the highest Ca-Eskola content (18 mol%) at 6 GPa (60 kbar), 1350 ° C and the presence of kyanite . They could not observe a pressure dependence of the Ca-Eskola content in the range of 2.5-15 GPa and concluded with the finding that the incorporation of voids in pyroxene is not an indicator of very high pressure. They explain the segregation of quartz in clinopyroxene as the result of a cooling of Ca-Eskola-rich pyroxenes.

Sutao Zhao and co-workers at the University of California, Riverside conducted similar research . They found the highest Ca-Eskola levels (32–38 mol%) also at 6 GPa. At higher pressures they observe a decrease in the Ca-Eskola content of their pyroxenes, which they attribute on the one hand to the increasing dissolution of pyroxene in garnet as majorite and on the other hand to the conversion of coesite into stishovite . They explain the segregation of quartz in clinopyroxene as the result of a depressurization of Ca-Eskola-rich pyroxene. The decrease in Ca-Eskola levels above 6 GPa was later observed by a working group at the Johann Wolfgang Goethe University in Frankfurt am Main .

The first syntheses of Tissintite with a composition similar to that of the meteoritic material were made by Melinda J. Backpack and colleagues from Stony Brook University in New York State . They synthesized clinopyroxene with ~ 50 mol% Ca-Eskola component from anorthite-rich plagioclase (labradorite) at 6-8 GPa and 1000-1350 ° C.

classification

In the structural classification of the International Mineralogical Association (IMA), Tissintite was not assigned to any of the pyroxene groups. As the calcium-to-analog of Jadeit Si or analog of Kushiroit he could with augite , Burnettit , Davisit , diopside , Esseneit , Grossmanit , Petedunnit , Hedenbergit , Johannsenite and Kushiroit be placed in the subset of Kalziumpyroxene.

The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and has so far been used by the IMA, does not yet list Tissintit. It would have been assigned to the class of "silicates and germanates" and there in the department of "chain and band silicates (inosilicates)". This section is further subdivided according to the type of chain formation, so that the mineral is classified according to its structure in the sub-section “Chain and band silicates with 2-periodic single chains Si2O6; Pyroxene Family ”would be found.

Even the outdated, but still in use, 8th edition of the mineral classification according to Strunz does not know the Tissintit. Here it would belong to the mineral class of "silicates and germanates" and there to the department of "chain silicates and band silicates (inosilicates)", where together with aegirine , augite, diopside, petedunnite, esseneit, hedenbergite, jadeite , jervisite , johannsenite, kanoite , clino , Klinoferrosilit , Kosmochlor , Namansilit , Natalyit , omphacite , pigeonite and spodumene the "pyroxene, clinopyroxene subgroup" with the system no. VIII / F.01 .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , would place Tissintit in the class of "silicates and Germanates" and there in the department of "chain silicate minerals". Here it could be found in the subsection “ Chain Silicates: Simple unbranched chains, W = 1 with chains P = 2 ”.

Chemism

Tissintit is the calcium analogue of jadeite and has the composition of plagioclase . An idealized composition that corresponds to pure anorthite would be [M2] (Ca 0.75 □ 0.25 ) [M1] Al [T] (Si 1.5 Al 0.5 ) O 6 , where [M2], [M1 ] and [T] are the positions in the pyroxene structure. A requirement for a final link composition is that a maximum of two different ions , atoms or molecules occur in only one lattice position (M1, M2 or T) . The end link known as the Ca-Eskola component [M2] (Ca 0.5 □ 0.5 ) [M1] Al [T] Si 2 O 6 is sufficient for this .

The composition of the Tissintit is from the type locality

  • [M2] (Ca 0.45 Na 0.31 □ 0.24 ) [M1] (Al 0.97 Fe 0.03 Mg 0.01 ) [T] (Si 1.8 Al 0.2 ) O 6

and is a mixed crystal of the Ca-Eskola terminal link with jadeite and kushiroite , corresponding to the exchange reactions

  • [M2] □ + [T] Si 4+ = [M2] Na + + [T] Al 3+ (jadeite)
  • [M2] □ + 2 [T] Si 4+ = [M2] Ca 2+ + 2 [T] Al 3+ (kushiroite)

In the presence of free SiO 2 , the kushiroite and Ca-Eskola content in Clinopyroxene is coupled via the decomposition reaction of the Ca-Eskola component:

  • 2 (Ca 0.5 □ 0.5 ) AlSi 2 O 6 = CaAl 2 SiO 6 + 3 SiO 2 .

A second type of tissintite from the Zagami meteorite is richer in magnesium and iron and has the composition

  • [M2] (Ca 0.42 Mg 0.24 Na 0.20 K 0.01 □ 0.13 ) [M1] (Al 0.52 Fe 0.38 Mg 0.08 Ti 0.01 Mn 0.01 ) [T] (Si 1.93 Al 0.07 ) O 6

This corresponds to a mixed crystal from Tissintit with Augite and Pigeonit , which occur in the vicinity of this Tissintite.

Crystal structure

Tissintite crystallizes with monoclinic symmetry in the space group C 2 / c (space group no. 15) with 4 formula units per unit cell . The lattice parameters of the natural tissue titanium are a  = 9.21 (17) Å, b  = 9.09 (4) Å, c  = 5.20 (2) Å and β = 109.6 (9) °. The volume of the unit cell at ~ 410 Å 3 is unusually small for clinopyroxenes and is still below that of diopside-jadeite mixed crystals of comparable composition. Template: room group / 15

The structure is that of clinopyroxene. Silicon (Si 4+ ) and aluminum (Al 3+ ) occupy the tetrahedral T-position surrounded by 4 oxygen ions, the octahedral M1 position surrounded by 6 oxygen is occupied by aluminum (Al 3+ ) and the octahedral-coordinated M2 position is only partially occupied with calcium (Ca 2+ ) and sodium (Na + ). Up to ~ 1/3 of the calcium position M2 can be unoccupied.

Education and Locations

Tissintite has so far only been found in some Martian meteorites (shergottites) and a eukrit . It forms during impact metamorphosis as a result of meteorite impacts and crystallizes in melt pockets of maskelynite , an anothite-rich plagioclase that was converted into glass during impact metamorphosis and partially melted. Experiments on the conversion of labradorite, an anorthite-rich plagioclase, showed that maskelynite forms from plagioclase at up to ~ 29 GPa at the beginning of the impact metamorphosis. Tissintite then forms from maskelynite when the pressure drops at 6–8 GPa and 1350–1000 ° C.

Meteorites

The type locality is the Tissint meteorite, a shergottite that fell on June 18, 2011 at around 2 a.m. southeast of Tata in Morocco . Tissintite occurs here in melting pockets with a plagioclase composition, which are surrounded by pigeonite and fayalite. Other high-pressure minerals that do not come into direct contact with Tissintit are ringwoodite , ahrensite , and chenmingite .

Tissinite occurs together with maskelynite in meteorite NWA 8159, an augite-rich basalt from Mars. Other high-pressure minerals here are ahrensite, stishovite and majorite - rich garnet.

In the Northwest Africa (NWA) 8003 meteorite, a basaltic eucrite whose origin is assumed to be in the asteroid (4) Vesta , Tissintite was observed in maskelynite in the immediate vicinity of melt ducts. Other high-pressure minerals here are coesite , stishovite and silicon-rich garnet.

In the Zagami meteorite, also a basaltic shergottite, a Tissintite-Pigeonite mixed crystal occurs together with a hexagonal calcium aluminosilicate, which also has the composition of plagioclase.

Terrestrial ultra-high pressure rocks

Tissintite has not yet been detected in the rocks of the earth. Pyroxenes from rocks of the earth's mantle, mainly eclogites containing kyanite, can contain a considerable amount of tissue and are an important indicator of their origin in the earth's mantle. In eclogites, the Ca-Eskola content of the pyroxenes reaches a maximum of ~ 15-20 mol% at a depth of ~ 130-180 km (4-6 GPa) under the conditions of the upper mantle .

These rocks only rarely reach the earth's surface in the course of mountain formation processes or as foreign rock inclusions in kimberlites. The pyroxenes found so far usually contain 10–15 mol% Ca-Eskola. Adhesions of clinopyroxene with quartz or plagioclase, which are interpreted as degradation products of Ca-Eskloa-rich pyroxene, are often observed.

The working group around NV Sobolev reported in 1968 about aluminum-rich clinopyroxenes with a cation deficit from garnet-pyroxene- kyanite - foreign rock inclusions in Siberian kimberlites and Joseph R. Smyth from Los Alamos Scientific Laboratory described milky white, very aluminum-rich clinopyroxenes from coesite - leading eclogites of Roberts- Victor kimberlits. He attributed the turbidity to the segregation of quartz and Ca-Tschermak- Pyroxen ( Kushiroite ), which separate from the vacancy pyroxene component (Ca 0.5 □ 0.5 AlSi 2 O 6 ) during the breakdown .

Omphazites from kyanite eclogites of the upper mantle, which were transported to the surface in the South African kimberlites Roberts-Victor and Bellsbank, were also examined by Tamsin C. McCormick in 1986. He found Ca-Eskola levels of ~ 13 mol%.

Oriented segregation of quartz in clinopyroxene was also observed in ultra-high pressure rocks of the Kokchetav massif in Kazakhstan , which uncrystallized in the stability range of diamond at pressures above 6 GPa and temperatures above 1000 ° C. Pyroxene inclusions in zircon contain up to 18 mol% Ca-Eskola component. Katayama and his colleagues at the Tokyo Institute of Technology, like Smyth 20 years earlier, interpret the segregation of quartz as a decomposition reaction from Ca-Eskola to kushiroite and quartz.

In the Dora Maira massif in the western Alps, geoscientists from the University of Turin found jadeite - pseudomorphoses after plagioclase with 10–17 mol% Ca-Eskola component in 2002 . In the same year Lifei Zhang and colleagues from Peking University described quartz segregation in clinopyroxenes from eclogites in western Tian Shan , China . Here, too, the Ca-Eskola contents are 11-17 mol%.

Web links

Individual evidence

  1. ↑ Tissintit in: IMA Database of Mineral Properties
  2. ↑ a b c d Chi Ma, Yang Liu and Oliver Tschauner: Tissintite, IMA 2013-027. NMNC Newsletter No. Aug 16, 2013, page 2707; . In: Mineralogical Magazine . tape 77 , 2013, p. 2695-2709 ( degruyter.com [PDF; 259 kB ; accessed on January 19, 2019]).
  3. ↑ a b c d e f g h i j k l Chi Ma, Oliver Tschauner, John R. Beckett, Yang Liu, George R. Rossman, Kirill Zuravlev, Vitali Prakapenka, Przemyslaw Dera, Lawrence A. Taylor: Tissintite, (Ca , Na, □) AlSi2O6, a highly-defective, shock-induced, high-pressure clinopyroxene in the Tissint martian meteorite . In: Earth and Planetary Science Letters . tape 422 , 2015, p. 194–205 ( https://www.osti.gov/pages/servlets/purl/1332404 (preprint) [PDF; 1.8 MB ; accessed on January 19, 2019]).
  4. ↑ a b c Chi Ma, Oliver Tschauner, John R. Beckett, Yang Liu, George R. Rossman, Kirill Zuravlev, Vitali Prakapenka, Przemyslaw Dera, Stanislav Sinogeikin, Jesse Smith, Lawrence A. Taylor: FIRST NEW MINERALS FROM MARS: DISCOVERY OF AHRENSITE γ-Fe2SiO4 AND TISSINTITE (Ca, Na, □) AlSi2O6, TWO HIGH PRESSURE PHASES FROM THE TISSINT MARTIAN METEORITE. In: Eighth International Conference on Mars . 2014, p. 1317–1318 ( usra.edu [PDF; 842 kB ; accessed on January 19, 2019]).
  5. ↑ EL Walton, TG Sharp, J. Hu, J. Filiberto: Heterogeneous mineral assemblages in martian meteorite Tissint as a result of a recent small impact event on Mars . In: Geochimica et Cosmochimica Acta . tape 140 , 2014, p. 334–348 ( researchgate.net [PDF; 3.2 MB ; accessed on April 29, 2020]).
  6. Jump up ↑ A. Ibhi, H. Nachit, El H. Abia: Tissint Meteorite: New Mars Meteorite fall in Morocco . In: J. Mater. Environ. Sci. tape 4 (2) , 2013, pp. 293–298 ( jmaterenvironsci.com [PDF; 365 kB ; accessed on January 21, 2019]).
  7. ↑ CA Goodrich & GE Harlow: Knorringite-Uvarovite Garnet and Cr-Eskola Pyroxene in Ureilite LEW 88774 . In: Meteoritics & Planetary Science . 36, Supplement, 2002, pp. A68 , bibcode : 2001M & PSA..36R..68G .
  8. ^ Pentti Eskola: On the eclogites of Norway . 1921, p. 118 ( google.de [accessed on February 2, 2019]).
  9. ↑ a b DE Vogel: Nature and chemistry of the formation of clinopyroxene-plagioclase symplectite from omphacite . In: New yearbook for mineralogy monthly books . tape 6 , 1966, pp. 185–189 ( eurekamag.com [accessed February 3, 2019]).
  10. ↑ Bernard J. Wood and CMB Henderson: Compositions and unit-cell parameters of synthetic non-stoichiometric tschermakitic clinopyroxen . In: American Mineralogist . tape 63 , 1978, pp. 66–72 ( minsocam.org [PDF; 659 kB ; accessed on February 10, 2019]).
  11. ↑ Masato Okui, Haruo Sawada, Fumiyuki Marumo: Structure refinement of a nonstoichiometric pyroxene synthesized under ambient pressure . In: Physics and Chemistry of Minerals . tape 25 , 1998, pp. 318-322 , doi : 10.1007 / s002690050121 .
  12. ^ Jürgen Konzett, Daniel J. Frost, Alexander Proyer, Peter Ulmer: The Ca-Eskola component in eclogitic clinopyroxene as a function of pressure, temperature and bulk composition: an experimental study to 15 GPa with possible implications for the formation of oriented SiO2-inclusions in omphacite . In: Contributions to Mineralogy and Petrology . tape 155 (2) , 2008, pp. 215-228 ( researchgate.net [PDF; 944 kB ; accessed on February 10, 2019]).
  13. ↑ a b Sutao Zhao, Philip Nee, Harry W. Green, Larissa F. Dobrzhinetskaya: Ca-Eskola component in clinopyroxene: Experimental studies at high pressures and high temperatures in multianvil apparatus . In: Earth and Planetary Science Letters . tape 307 , 2011, pp. 517-524 , doi : 10.1016 / j.epsl.2011.05.026 .
  14. ↑ a b c NADIA KNAPP, ALAN B. WOODLAND and KEVIN KLIMM: Experimental constraints in the CMAS system on the Ca-Eskola content ofeclogitic clinopyroxene . In: European Journal of Mineralogy . tape 25 , 2013, p. 579-596 ( researchgate.net [PDF; 1.5 MB ; accessed on February 10, 2019]).
  15. ^ A b MJ Rucksack, ML Whitaker, TD Glotch, and JB Parise: Tissintite: An Experimental Investigation into an Impact-Induced, Defective Clinopyroxene. In: Acta Crystallographica . A73, 2017, p. 245 ( iucr.org [PDF; 593 kB ; accessed on January 16, 2019]).
  16. ^ A b Melinda J. Rucksack, Matthew L. Whitaker, Timothy D. Glotch, John B. Parise, Steven J. Jaret, Tristan Catalano, and M. Darby Dyar: Making tissintite: Mimicking meteorites in the multi-anvil . In: American Mineralogist . tape 103 , 2018, p. 1516–1519 ( sunysb.edu [PDF; 1.1 MB ; accessed on January 16, 2019]).
  17. ↑ Hawthorne FC: The Use Of End-Member Charge-Arrangements In Defining New Mineral Species And Heterovalent Substitutions In Complex Minerals. In: The Canadian Mineralogist. 40, 2002, pp. 699-710. ( PDF (309 kB) )
  18. ↑ a b Chi Ma and John R. Beckett: A NEW TYPE OF TISSINTITE, (Ca, Mg, Na, □ 0.14) (Al, Fe, Mg) Si2O6, IN THE ZAGAMI MARTIAN METEORITE: A HIGH-PRESSURE CLINOPYROXENE FORMED BY SHOCK . In: Lunar and Planetary Science XLVIII . 2017, p. 1639–1640 ( usra.edu [PDF; 1,4 MB ; accessed on January 19, 2019]).
  19. ↑ Chi Ma, Oliver Tschauner, John R. Beckett, Yang Liu: DISCOVERY OF CHENMINGITE, FeCr2O4 WITH AN ORTHORHOMBIC CaFe2O4-TYPE STRUCTURE, A SHOCK-INDUCED HIGH-PRESSURE MINERAL IN THE TISSINT MARTIAN METEORITE. In: 49th Lunar and Planetary Science Conference . 2018, p. 1564–1565 ( usra.edu [PDF; 1.7 MB ; accessed on January 16, 2019]).
  20. ↑ Tom G. Sharp, Erin L. Walton, Jinping Hu, Carl Agee: Shock conditions recorded in NWA 8159 martian augite basalt with implications for the impact cratering history on Mars (Accepted Manuscript) . In: Geochimica et Cosmochimica Acta . 2018 ( caltech.edu [PDF; 1.5 MB ; accessed on January 16, 2019]).
  21. ↑ Run-Lian Pang, Ai-Cheng Zhang, Shu-Zhou Wang, Ru-Cheng Wang & Hisayoshi Yurimoto: High-pressure minerals in eucrite suggest a small source crater on Vesta . In: Scientific Reports . tape 6 , 2016 ( nature.com [accessed January 20, 2019]).
  22. ↑ Chi Ma, Oliver Tschauner, John R. Beckett: A NEW HIGH-PRESSURE CALCIUM ALUMINOSILICATE (CaAl2Si3.5O11) IN MARTIAN METEORITES: ANOTHER AFTER-LIFE FOR PLAGIOCLASE AND CONNECTIONS TO THE CAS PHASE. In: Lunar and Planetary Science XLVIII . 2017, p. 1128–1129 ( semanticscholar.org [PDF; 1.4 MB ; accessed on January 19, 2019]).
  23. ↑ F. Schroeder-Frerkes, AB Woodland, L. Uenver-Thiele, K. Kliomm, N. Knapp: Ca-Eskola incorporation in clinopyroxene: limitations and petrological implications for eclogites and related rocks . In: Contributions to Mineralogy and Petrology . tape 171 , 2016, doi : 10.1007 / s00410-016-1311-3 .
  24. ^ A b JR Smyth: Silica-bearing eclogites from the Roberts-Victor kimberlite . In: International Kimberlite Conference: Extended Abstracts . 1977, p. 322–324 (ikcabstracts.com/index.php/ikc/article/download/1036/1036 [PDF; 728 kB ; accessed on February 3, 2019]).
  25. ^ A b Joseph R. Smyth: Cation vacancies and the crystal chemistry of breakdown reactions in kimberlitic omphacite . In: American Mineralogist . tape 65 , 1980, pp. 1185–1191 ( minsocam.org [PDF; 665 kB ; accessed on February 5, 2019]).
  26. ↑ a b IKUO KATAYAMA, CHRISTOPHER D. PARKINSON, KAZUAKI OKAMOTO, YOUICHI NAKAJIMA, AND SHIGENORI MARUYAMA: Supersilicic clinopyroxene and silica exsolution in UHPM eclogite and pelitic gneiss from the Kokchetav massif, Kazakhstan . In: American Mineralogist . tape 85 , 2000, pp. 1368-1374 ( researchgate.net [PDF; 908 kB ; accessed on February 9, 2019]).
  27. ↑ NV SOBOLEV, JR. IK KUZNETSOVA NI ZYUZIN: The Petrology of Grospydite Xenoliths from the Zagadochnaya Kimberlite Pipe in Yakutia . In: Journal of Petrology . tape 9 , 1968, p. 253-280 , doi : 10.1093 / petrology / 9.2.253 .
  28. ^ Tamsin C. McCormick: Crystal-chemical aspects of nonstoichiometric pyroxenes . In: American Mineralogist . tape 71 , 1986, pp. 1434–1440 ( minsocam.org [PDF; 849 kB ; accessed on February 9, 2019]).
  29. ↑ Marco Bruno, Roberto Compagnoni, Takao Hirajima, Marco Rubbo: Jadeite with the Ca-Eskola molecule from an ultra-high pressure metagranodiorite, Dora-Maira Massif, Western Alps . In: Contributions to Mineralogy and Petrology . tape 142 , 2002, p. 515-519 ( amazonaws.com [PDF; 254 kB ; accessed on February 9, 2019]).
  30. ↑ LIFEI ZHANG, DAVID J. ELLIS, AND WENBO JIANG: Ultrahigh-pressure metamorphism in western Tianshan, China: Part I. Evidence from inclusions of coesite pseudomorphs in garnet and from quartz exsolution lamellae in omphacite in eclogites . In: American Mineralogist . tape 87 , 2002, pp. 853-860 ( psu.edu [PDF; 1.5 MB ; accessed on February 9, 2019]).
  31. ↑ LIFEI ZHANG, YONGLIANG AI, SHUGUANG SONG, JUHN LIOU AND CHUNJING WEI: A Brief Review of UHP Meta-ophiolitic Rocks, Southwestern Tianshan, Western China . In: International Geology Review . tape 49 , 2007, p. 811–823 ( edu.cn [PDF; 3.5 MB ; accessed on February 9, 2019]).