Schorlomit

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Schorlomit
Mélanite-Mali.jpg
Melanite from Deacon, Kayes Region, Mali
General and classification
other names

Ferrotitanite, Ivaarite, Iiwaarite

chemical formula Ca 3 Ti 2 Fe 3+ 2 SiO 12
Mineral class
(and possibly department) 		Silicates and Germanates
System no. to Strunz
and to Dana 		9.AD.25 ( 8th edition : 8 / A.08-120)
51.4.3c.1
Similar minerals Titanandradite (melanite), morimotoite, augite, schörl
Crystallographic Data
Crystal system cubic
Crystal class ; symbol cubic hexakisoctahedral; 4 / m  3  2 / m
Space group Ia 3 d (No. 230)Template: room group / 230
Lattice parameters a  = 12.1524  Å
Formula units Z  = 8
Physical Properties
Mohs hardness 7 - 7.5
Density (g / cm 3 ) natural mixed crystal: measured: 3.862; calculated: 3.800
Cleavage indistinct
Break ; Tenacity shell-like
colour black
Line color grey black
transparency Please complete!
shine Glass gloss
Crystal optics
Refractive index n  = 1.95 (natural mixed crystal)
Birefringence δ = -

The mineral schorlomite , outdated also known as ferrotitanite and ivaarite or Iiwaarite , is a very rare island silicate from the upper group of garnets with the idealized chemical composition Ca 3 Ti 2 Fe 3+ 2 SiO 12 . It crystallizes in the cubic crystal system with the structure of garnet.

Schorlomit is translucent, orange-brown to black, often rhombendodekaedrische crystals with glass to slightly metallic sheen that a few centimeters can be large. The color becomes more intense as the titanium content increases. With increasing Fe 2+ content, the color changes from yellow to dark red-violet and the crystals then appear opaque black with an almost metallic sheen. Often the crystals show a complex and rhythmic zoning as well as sector zoning. Even crystals that appear microscopically uniform can be adhesions of two to three garnets that can be distinguished by radiography . The resulting distortions of the crystal lattice make these garnets optically birefringent .

Finds have been described from basic igneous rocks, carbonatites and contact metamorphic calcareous rocks and skarns . In addition to its type locality , the Magnet Cove carbonatite complex in Hot Spring County , Arkansas , USA , around 60 other sites have been documented for Schorlomit worldwide. Strictly speaking, many of the grenades referred to as schorlomite are titanium andradite ( melanite ). A schorlomite composition could only be confirmed for very few samples with the help of very complex analyzes.

Etymology and history

Schorlomite (black) from the Magnet Cove carbonatite complex, together with cream-colored thomsonite-Ca, the ozarkite from Shepard

The first scientific description of Schorlomit comes from the year 1846 and the exact location is not known. Chemistry professor Charles Upham Shepard , of South Carolina Medical College , received the samples from Reverend ER Beadle, who is believed to have collected them on a trip to the Hot Springs area. This legacy of the former missionary still occupies science today. First, Shepard was able to describe three new minerals in addition to diamond : arkansite, which was already known as brookite , ozarkite, which is thomsonite-Ca and a black, strongly shiny mineral that he called schorlomite because of its similarity to Schörl .

The first chemical analyzes of these Schorlomites come from Whitney (1849) and Carl Rammelsberg (1850). They characterized schorlomite as a Ca-Fe-Ti silicate.

Two years later, in 1852, a similar mineral was described in the Iivaara complex ( Finland ) under the name Iivaarit and in 1877 Schorlomite vom Kaiserstuhl in Germany. This was followed by numerous finds of titanium-rich grenades at many sites around the world and a discussion that has now been going on for over 160 years as to what exactly schorlomite is and how it can be distinguished from other grenades. This was done first through various Ti contents in the empirical formula and later through the occupation of the various positions of the garnet structure with iron, titanium and silicon.

In 1933, Zedlitz designated grenades with more than 15% by weight of TiO 2 as schorlomite, in 1962 Kukharenko and Bagdasarov suggested 0.75 apfu Ti as the minimum Ti content of schorlomite (~ 11% by weight), which Howie and Woolley undercut in 1968 (0.5 apfu Ti). In 1972, Roberts and his colleagues went even further and did not even list the schorlomite in their Encyclopedia of Minerals , but only spoke of "titanium-containing andradite".

The currently accepted formula for the Schorlomite terminal link Ca 3 Ti 2 Fe 3+ 2 SiO 12 was proposed by Ito and Frondel in 1967, while Rickwood in 1968 defined the Schorlomite terminal link entirely without Si (Ca 3 Ti 2 Fe 3+ 2 TiO 12 ). Both formulas determine in which oxidation state iron (Fe 3+ ) and titanium (Ti 4+ ) occur in which lattice position of the garnet, albeit differently - information that can only be obtained with a high level of analytical effort and for hardly anyone as schorlomite designated grenade are present. Many of the structural formulas proposed later are kept more general and describe mixed crystals without specifying a specific end link. Deer, Howie and Zussman, in their standard work on rock-forming minerals in 1982, defined schorlomite as a garnet with more Ti than Fe 3+ in the octahedral Y position. In 1995 Anthony and his co-workers state the schorlomite formula with Ca 3 (Ti 4+ , Fe 3+ ) 2 (Si, Fe 3+ ) 3 O 12 in the Handbook of Mineralogy, and Gaines et al. in Dana's new mineralogy 1997 with Ca 3 (Ti 4+ , Fe 3+ , Al) 2 (Si, Fe 3+ , Fe 2+ ) 3 O 12 .

In 1997, Rass and Dubrovinskii proposed the novel end link Ca 3 Ti 3+ 2 Ti 4+ 3 O 12 and Yakovenchuk et al. 1999 brought a Ti hydrogranate with the composition Ca 3 (Ti 4+ , Fe 2+ ) 2 [(SiO 2 ) 2 (OH) 4 ] into play.

Chakhmouradian and McCammon defined schorlomite as Ca 3 Ti 4+ 2 [Si 3-x (Fe 3+ , Al, Fe 2+ ) x ] O 12 in 2005 , before Grew's working group restructured the garnet group in 2013 and added the schorlomite the ideal composition Ca 3 Ti 2 Fe 3+ 2 SiO 12 accepted by the IMA today in the schorlomite group. They give a scheme with which, in the absence of a direct determination of the cation distribution on the lattice positions of the garnet structure (spectroscopic, X-ray diffraction), this can be calculated and found that a large part of the garnets called schorlomite are in the composition range of andradite .

In 2016, Emanuela Schingaro and her co-authors investigated the crystal chemistry of Ti-Fe garnets, which according to the calculation scheme of Grew et al. is schorlomite and was able to show that their compositions are also in the field of andradite. After more than 160 years of research on Ti-containing garnets and numerous, mostly hypothetical, solid solution pendants, the assessment of Roberts and his colleagues from 1972 is almost confirmed: Schorlomite is an important solid solution component in Ti garnets, but almost does not occur in nature as an independent mineral . The few exceptions include some analyzes of schorlomite from the Magnet Cove type locality in the Hot Springs region, the origin of the legacy of Reverent ER Beadle.

classification

The current classification of the International Mineralogical Association (IMA) counts the schorlomite to the garnet upper group, where together with kimzeyite , irinarassite , hutcheonite , kerimasite and toturite it forms the schorlomite group with 10 positive charges on the tetrahedral coordinated lattice position.

The obsolete, but still used the eighth edition of the mineral classification by Strunz takes the Schorlomit along with almandine Andradite , Calderit , Goldmanit , Grossular , Henritermierit , Hibschite , Holtstamit , Hydrougrandit , katoite , Knorringit , majorite , Morimotoit , pyrope , Spessartin , Uwarowit , wadalite and Yamatoit (discredited because it is identical to Momoiit ) in the "garnet group" with the system no. VIII / A.08 in the department of " Island Silicates (Nesosilicates)".

Also the 9th edition of the Strunz'schen mineral systematics, valid since 2001, counts the Schorlomit to the "garnet group" with the system no. 9.AD.25 within the department of "Island Silicates (Nesosilicates)". This is further subdivided according to the possible presence of further anions and the coordination of the cations involved , so that the mineral is classified according to its composition in the subsection “Island silicates without additional anions; Cations in octahedral [6] and usually greater coordination ”can be found. The garnets irinarassite , hutcheonite , kerimasite , toturite , menzerite- (Y) and eringaite , described after 2001, would also have been classified in the garnet group.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Schorlomit to the section of "island silicate minerals ". Here he is together with Kimzeyit and Morimotoit in the "Garnet group (Schorlomit-Kimzeyit-series)" with the system no. 51.04.03c within the subsection “ Island silicates: SiO 4 groups only with cations in [6] and> [6] coordination ”.

Chemism

Schorlomite with the idealized composition [X] Ca 3 [Y] Ti 2 [Z] (Fe 3+ 2 Si) O 12 is the Fe analogue of hutcheonite ( [X] Ca 3 [Y] Ti 2 [Z] (Al 3+ 2 Si) O 12 ) and forms complex mixed crystals especially with andradite according to the exchange reaction

  • [Y] Ti 4+ + [Z] Fe 3+ = [Y] Fe 3+ + [Z] Si 4+ ,

Morimotoite corresponding to the exchange reaction

  • [Y] Ti 4+ + 2 [Z] Fe 3+ = [Y] Fe 2+ + 2 [Z] Si 4+

and Kerimasit on the reaction

  • [Y] Ti 4+ = [Y] Zr 4+ ,

where [X], [Y] and [Z] indicate the positions in the garnet structure.

For schorlomitic grenades from the type locality Magnet Cove the following compositions are given:

  • [X] (Ca 2.790 Mn 0.050 Fe 2+ 0.237 Mg 0.180 ) [Y] (Ti 4+ 0.169 Fe 3+ 1.071 Al 0.532 ) [Z] (Si 2.254 Ti 4+ 0.746 ) O 12
  • [X] (Ca 2.790 Mn 0.050 Fe 2+ 0.148 Mg 0.012 ) [Y] (Ti 4+ 1.003 Ti 3+ 0.06 Fe 3+ 0.770 Mg 0.168 Fe 2+ 0.029 Mn 0.026 ) [Z] (Si 2.254 Fe 3 + 0.361 Al 0.385 ) O 12
  • [X] (Ca 2.915 Mn 0.034 Fe 2+ 0.031 Na 0.020 ) [Y] (Ti 4+ 1.054 Zr 4+ 0.065 Fe 3+ 0.530 Mg 0.158 Fe 2+ 0.200 Nb 0.002 ) [Z] (Si 2.263 Fe 3+ 0.580 Al 0.157 ) O 12
  • [X] (Ca 2.98 Mn 0.01 Na 0.01 ) [Y] (Ti 4+ 0.54 Ti 3+ 0.06 Fe 3+ 1.18 Al 0.09 Mg 0.13 ) [Z ] (Si 2.58 Fe 3+ 0.28 Al 0.12 □ 0.02 ) O 11.92 (OH) 0.08

The determination of the composition of natural Ti-Fe garnets is problematic in several respects. On the one hand, the crystals are usually very inhomogeneous, zoned and contain inclusions, which makes all investigations that require larger sample quantities (wet chemical analyzes, crystal structure analysis , Mössbauer spectroscopy ) difficult. Birefringent crystals can consist of submicroscopic adhesions of several garnets. Even point analyzes with a size of a few µm such as B. Electron beam microanalyses , which make up the majority of all chemical analyzes, should be interpreted with caution against this background if they come from birefringent crystals.

On the other hand, the elements iron (Fe) and titanium (Ti) can occur in several oxidation states and in different positions of the garnet structure. If there are no direct measurements of the oxidation states of iron (Fe 2+ , Fe 3+ ) and titanium (Ti 3+ , Ti 4+ ), they are determined mathematically by normalizing the analyzes to 8 cations and 12 oxygen atoms. Here all measurement inaccuracies accumulate in the calculated Fe 2+ / Fe 3+ and Ti 4+ / Ti 3+ ratios. The distribution to the various grid positions is also done mathematically, guided by comparisons with other minerals and crystal-chemical plausibility considerations. These assumptions often turned out to be imprecise. Overall, this leads z. B. on fictitious Ti 3+ contents or incorrect distribution of Ti and Fe on the grid positions and, as a result, incorrect assignments of mineral names (schorlomite instead of morimotoite or andradite).

A few Ti-Fe grenades from different deposits were examined by means of a Mössbauer spectroscopy, which allows different oxidation states and lattice positions of iron to be distinguished. The spectra are often complex with strong overlapping of the individual signals and have been interpreted differently for Fe 2+ by different working groups . Some find here evidence of Fe 2+ on the tetrahedral Z-position normally occupied by Si 4+ . This interpretation is supported by infrared spectra . Other working groups argue against tetrahedral Fe 2+ and interpret the same signal as an electron exchange between Fe 2+ on the dodecahedron position (X) or octahedral position (Y) and Fe 3+ on the tetrahedral position (Z). A Chinese working group sees both electron exchange reactions side by side in their Mössbauer spectra.

The oxidation state and spatial distribution of titanium in the garnet has rarely been determined directly. Early considerations assume the incorporation of Ti 4+ in the tetrahedral Z position and Ti 3+ in the octahedral Y position. X-ray near-edge absorption spectra of titanium in garnet, on the other hand, show that titanium is only incorporated in the octahedral Y position and gives no indication of Ti 3+ . With a few exceptions, the oxygen fugacities in the earth's crust are too high for Ti 3+ and significant amounts of Ti 3+ in garnet are only assumed for garnets of meteoritic origin ( eringaite ).

Crystal structure

Schorlomite crystallizes with cubic symmetry in the space group Ia 3 d (space group no. 230) with 8 formula units per unit cell . The natural mixed crystal from the type locality has the lattice parameter a  = 12.187  Å . Template: room group / 230

The crystal structure is that of garnet . Calcium (Ca 2+ ) occupies the dodecahedral X positions surrounded by 8 oxygen ions, titanium (Ti 4+ ) the octahedral Y position surrounded by 6 oxygen ions and the tetrahedral Z position surrounded by 4 oxygen ions is iron (Fe 3+ ) and silicon (Si 4+ ) occupied.

Education and Locations

Shorlimite-rich garnets form magmatically in alkali-rich, basic to ultra-basic magmatites or metamorphically in skarns during the contact metamorphosis of calcareous silicate rocks such as B. Marl . Around 60 sites around the world are documented, almost all of which do not contain schorlomite but titanium andradite ( melanite ).

Carbonatite complexes

Schorlomite (black) and nepheline (white) from Bou-Agrao Mountain, Tamazeght complex, High Atlas Mts, Khénifra Province, Meknes-Tafilalet Region, Morocco

Schorlimit-rich garnets of igneous origin are found worldwide in both carbonatites and in the accompanying alkali-rich, basic to ultra-basic igneous rocks .

The type locality of schorlomite is the Magnet Cove carbonatite complex in Hot Spring County , Arkansas , USA . There, schorlomite occurs in Ijolit , associated with diopside-rich clinopyroxene, biotite , cancrinite , natrolite , calcite , apatite , magnetite , perovskite and thomsonite-Ca . Deposits in the Ijolit from Iivaara (Ijola) in the Kuusamo region , Northern Ostrobothnia , Finland are comparable .

In the melteigite of the Ice River Alkali Complex in British Columbia , Canada , garnet rich in chorlomite occurs together with diopside, calcite, nepheline , apatite and pyrite .

In the silicocarbonatite of the Afrikanda Complex on the Kola Peninsula in the Murmansk Oblast of the Northwestern Federal District, shorlomite-rich garnet occurs together with magnesiohastingsite , calcite, magnetite, perovskite, titanite , clinochlor and various zirconium minerals.

In the polino-monticellite- calcite carbonatite in the Italian province of Terni (Umbria), schorlomitic andradite occurs together with forsterite- rich olivine, phlogopite , monticellite , thorium-containing perovskite and apatite in a finely crystalline matrix of calcite.

In the Tamazeght carbonatite complex south of Midlet in the High Atlas in Morocco , Ti-Andradite occurs in various rocks. In pyroxenites melanite occurs with clinopyroxene, nepheline, apatite, calcite, mica, magnetite, titanite and pyrite, in mica together with biotite, clinopyroxene, perovskite, magnetite and apatite. Andradites from olivine shonkinite show the highest titanium contents here , where they occur together with olivine , clinopyroxene, magnetite, apatite, alkali feldspar and nepheline.

The only occurrence of this kind in Germany, the Phonolith - tuffs and transitions of the Kaiserstuhl z. B. near Oberrotweil in Baden-Württemberg , have been known since the end of the 19th century.

Kimberlite

Ti-Fe garnets with up to 90 mol% schorlomite (calculated on the basis of chemical analyzes) were found in kimberlites of the Wajrakarur kimberlite field in the Anantapur district , Andhra Pradesh , India . They occur in the matrix of kimberlites of type II and were probably formed during the late phase of crystallization when spinels react with residual igneous solutions. Similar occurrences can be found in the Swartruggens Orangeit on the Kaapvaal craton in South Africa .

Skarns and Contalt Metamorphic Xenolites

Most of the German sites of grenade rich in schorlomite are in the Eifel . Here, Ti-rich andradites occur in Ca-rich xenolites in alkali basalts .

In the calcium silicate rock inclusions of the gabbro in the Radautal , Harz , schorlomitic garnets were described as early as the beginning of the 20th century.

At Flekkeren in the municipality of Skien in Telemark , Norway, there is a 100 m thick calcium silicate clod enclosed in larvikite , from which it has undergone contact metamorphosis at 820 to 870 ° C and low pressure. Here, schorlomitic garnet occurs together with wollastonite , augite , potassium feldspar and scapolite . In calcite-bearing areas, phlogopite and melilite are added.

A similar paragenesis can be found e.g. B. in the Zvezdel-Pcheloyad ore deposit in Eastern Rhodopes, Bulgaria . Here Ti-rich andradite occurs together with clinopyroxene , wollastonite, plagioclase and subordinate calcite, quartz, epidote , prehnite , melilite, chlorite , thaumasite and zeolites in skarn xenolites in monzonite.

See also

Web links

Individual evidence

  1. ↑ a b c d e f g h i j k AR Chakhmouradian, CA McCammon: Schorlomite: a discussion of the crystal chemistry, formula, and inter-species boundaries . In: Physics and Chemistry of Minerals . tape 32 , 2005, pp. 277–289 ( researchgate.net [PDF; 478 kB ; accessed on October 22, 2017]).
  2. ↑ a b c d e f g h i Charles U. Shepard: On three new mineral species from Arkansas, and the discovery of the diamond in North Carolina . In: American Journal of Science and Arts . tape 52 , no. 2 , 1846, p. 249–254 ( rruff.info [PDF; 486 kB ; accessed on October 22, 2017]).
  3. ↑ a b c d Howie, RA, AR Wooley, JH Scoon, RC Tyler & JN Walsh: The role of titanium and the effect of TiO2 on the cell size, refractive index, and specific gravity in the andradite-melanite-schorlomite series . In: Mineralogical Magazine . tape 36 , 1968, pp. 775–790 ( rruff.info [PDF; 2,3 MB ; accessed on November 6, 2017]).
  4. ^ A b Frank E. Huggins, David Virgo and H. Gerhard Huckenholz: Titanium-containing silicate garnets. II. The crystal chemistry of melanites and schorlomites . In: American Mineralogist . tape 62 , no. 7-8 , 1977, pp. 646 - 665 ( minsocam.org [PDF; 1.9 MB ; accessed on December 28, 2017]).
  5. ↑ a b S. Anato: The mystery of birefringent garnet: Is the symmetry lower than cubic? In: Powder Diffraction . tape 28 (4) , 2013, pp. 281-288 , doi : 10.1017 / S0885715613000523 .
  6. ↑ a b Sytle M. Antao, Shaheera Mohib, Mashrur Zaman, Robert A. Marr: Ti-rich Andraditres: Chemistry, Structure, Multi-Phases, Optical Anisotropy, And Oscillatory Zoning . In: The Canadian Mineralogist . tape 53 (1) , 2015, pp. 133-158 , doi : 10.3749 / canmin.1400042 .
  7. ↑ a b c d e Emanuela Schingaro, Maria Lacalamita, Ernesto Mesto, Gennaro Ventruti, Giuseppe Edrazzi, Luisa Ottolini, and Fernando Scordari: Crystal chemistry and light elements analysis of Ti-rich garnets . In: American Mineralogist . tape 101 , 2016, p. 371–384 ( minsocam.org [PDF; 1.1 MB ; accessed on October 22, 2017]).
  8. ↑ a b c d List of localities for Schorlomite at the Mineralienatlas and at Mindat
  9. ↑ a b c d e f Edward S. Grew, Andrew J. Locock, Stuart J. Mills, Irina O. Galuskina, Evgeny V. Galuskin and Ulf Hålenius: IMA Report - Nomenclature of the garnet supergroup . In: American Mineralogist . tape 98 , 2013, p. 785–811 ( main.jp [PDF; 2,3 MB ; accessed on July 8, 2017]).
  10. ↑ a b A. Knop: About the Schorlomit from the Kaiserstuhl. In: Journal of Crystallography - Crystalline Materials . tape 1 , no. 1-6 , 1877, pp. 58-65 , doi : 10.1524 / zkri.1877.1.1.58 .
  11. ↑ Jun Ito and Clifford Frondel: Synthetic zirconium and titanium garnets . In: American Mineralogist . tape 52 , no. 5-6 , 1967, pp. 773–781 ( minsocam.org [PDF; 545 kB ; accessed on July 8, 2017]).
  12. ↑ a b Kenneth B. Schwartz, Daniel N. Nolet and Roger G. Burns: Mössbauer spectroscopy and crystal chemistry of natural Fe-Ti garnet . In: American Mineralogist . tape 65 , 1980, pp. 142–153 ( minsocam.org [PDF; 1.4 MB ; accessed on December 11, 2017]).
  13. ^ A b Eric Dowty: Crystal chemistry of titanian and zirconian garnet: I. Review and spectral studies . In: The American Mineralogist . tape 56 , no. 11-12 , 1971, pp. 1983–2009 ( minsocam.org [PDF; 1.8 MB ; accessed on January 6, 2018]).
  14. ↑ G. Amthauer, H. Annersten, and SS Hafner: The Mössbauer Spectrum of 57Fe in Titanium-Bearing Andradites . In: Physics and Chemistry of Minerals . tape 1 , 1977, pp. 399-413 ( researchgate.net [PDF; 878 kB ; accessed on December 11, 2017]).
  15. ^ A Kühberger, T. Fehr, HG Huckenholz and G. Amthauer: Crystal Chemistry of a Natural Schorlomite and Ti-Andradites Synthesized at Different Oxygen Fugacities . In: Physics and Chemistry of Minerals . tape 16 , 1989, pp. 734-740 ( researchgate.net [PDF; 736 kB ; accessed on October 22, 2017]).
  16. ^ A b c Andrew Locock, Robert W. Luth, Ronald G. Cavell, Dorian GW Smith, M. John, M. Duke: Spectroscopy of the cation distribution in the schorlomite species of garnet . In: American Mineralogist . tape 80 , 1995, pp. 27–38 ( minsocam.org [PDF; 1.7 MB ; accessed on December 11, 2017]).
  17. ^ Raymond K. Moore and William B. White: Intervalence electron transfer effects in the spectra of the melanite garnets . In: The American Mineralogist . tape 56 , no. 5 - 6 , 1971, pp. 826-840 ( minsocam.org [PDF; 905 kB ; accessed on January 6, 2018]).
  18. ↑ Wu Gongbao, Mu Baolei: The crystal chemistry and Mössbauer study of schorlomite . In: Physics and Chemistry of Minerals . tape 13 , no. 3 , 1986, pp. 198-205 , doi : 10.1007 / BF00308162 .
  19. ↑ Emil Dittler: On the question of the oxidation level of titanium in the silicates . In: Meeting reports d. mathem. natural Kl . tape 8 issue 28, 1929, pp. 371–411 ( PDF on ZOBODAT [accessed December 11, 2017]).
  20. ↑ Chi Ma: Discovery Of Meteoritic Eringaite, Ca3 (Sc, Y, Ti) 2Si3O12, The First Solar Garnet? In: 75th Annual Meteoritical Society Meeting (2012) . 2012 ( usra.edu [PDF; 70 kB ; accessed on September 9, 2017]).
  21. ^ Marta JK Flor, Malcom Ross: Alkaline igneous rocks of Magnet Cove, Arkansas: Metasomatized ijolite xenoliths from Diamond Jo quarry . In: The American Mineralogist . tape 74 , 1989, pp. 113–131 ( minsocam.org [PDF; 2.5 MB ; accessed on January 1, 2018]).
  22. ↑ F. Stoppa, L. Lupini: Mineralogy and petrology of the Polino Monticellite Calciocarbonatite (Central Italy) . In: Mineralogy and Petrology . tape 49 , no. 3-4 , 1993, pp. 213-231 ( researchgate.net [PDF; 2.0 MB ; accessed on January 7, 2018]).
  23. ↑ Michael AW Marks, Julian Schilling, Ian M. Coulson, Thomas Wenzel, Gregor Markl: The Alkaline – Peralkaline Tamazeght Complex, High Atlas Mountains, Morocco: Mineral Chemistry and Petrological Constraints for Derivation from a Compositionally Heterogeneous Mantle Source . In: Journal of Petrology . tape 49 , no. 6 , 2008, p. 1097-1131 , doi : 10.1093 / petrology / egn019 .
  24. ↑ Ashish N. Dongre, KS Viljoen, NV Chalapathi Rao, A. Gucsik: Origin of Ti-rich garnets in the groundmass of Wajrakarur field kimberlites, southern India: insights from EPMA and Raman spectroscopy . In: Mineralogy and Petrology . tape 110 (2-3) , 2016, pp. 295-307 , doi : 10.1007 / s00710-016-0428-4 .
  25. ↑ S. Koritnig, H. Rösch, A. Schneider, F. Seifert: The titanium zirconium garnet from the calcium silicate rock inclusions of the gabbro in the Radautal, Harz, Federal Republic of Germany . In: TMPM Tschermaks Mineralogische und Petrographische Mitteilungen . tape 25 , no. 4 , December 1978, p. 305-313 , doi : 10.1007 / BF01180234 .
  26. ↑ Bjørn Jamtveit, Sven Dahlgren, and Haakon Austrheim: High-grade contact metamorphism of calcareous rocks from the Oslo Rift, Southern Norway . In: The American Mineralogist . tape 82 , no. 11-12 , 1997, pp. 1241–1254 ( minsocam.org [PDF; 1.9 MB ; accessed on January 7, 2018]).
  27. ↑ Yana Tzvetanova, Mihail Tarassov, Valentin Ganev, Iskra Piroeva: Ti-rich andradites in skarns from Zvezdel-Pcheloyad ore deposit, Eastern Rhodopes, Bulgaria . In: BULGARIAN GEOLOGICAL SOCIETY, National Conference with international participation “GEOSCIENCES 2015” . 2015, p. 41–42 ( bgd.bg [PDF; 1.3 MB ; accessed on January 7, 2018]).