Summary
Microprobe analyses and X-ray crystal structure refinement data of Mg-Fe-Al-Cr spinels from different environments are compared. The investigated crystals represent both restitic and recrystallized spinels from an Alpine peridotitic massif, and restitic spinels from four suites of ultramafic xenoliths. Within each suite the crystals represent different steps of an increasing melting process, which causes a strong increase in Cr3+ and a moderate increase in Fe2+, with depletion of Al3+ and Mg2+. Within each suite, in spite of relevant bulk chemistry changes, the ratio of the octahedral to tetrahedral coordination distances, and consequently the oxygen positional parameterx, are kept constant. Conversely,x may differ in suites with similar bulk chemistry, mainly due to different Mg-Al ordering between octahedral and tetrahedral sites. This suggests that thex parameter is strongly affected by physical environment, and that consequently, within the range of the investigated compositions, it could be used as a marker.
Zusammenfassung
EMS-Analyse und röntgenograhsch verfeinerte Kristallstrukturen von Mg-Fe-Al-Cr Spinellen aus verschiedenen petrologischen Situationen wurden verglichen. Unter den untersuchten Kristallen befinden sich sowohl restitische und rekristallisierte Spinelle aus alpinen Peridotiten, als auch restitische Spinelle aus vier Suiten von ultramafischen Xenolithen. Die Kristalle in jeder Suite gehören zu verschiedenen Stufen eines Schmelzprozesses, der ein starkes Anwachsen der Cr3+ - und ein mäßiges Anwachsen der Fe2+- Konzentration bei gleichzeitiger Verminderung des Al3+ - und Mg2+-Gehaltes, verursacht. Jede Suite zeigt, trotz bedeutender chemischer Veränderungen, ein feststehendes Verhältnis von oktaedrischen zu tetraedrischen Polyederdimensionen, weshalb der Sauerstoffparameter x unveränderlich bleibt. Jedoch sehen wir, daß sich diex von den Spinellen zweier verschiedener Suiten mit ähnlichem Chernismus unterscheiden, was auf die unterschiedliche Mg-Al- Anordnung in oktaedrischen und tetraedrischen Positionen zurückzuführen ist. Dies läßt vermuten, daß der Parameterx sehr stark von der petrogenetischen Situation abhängig ist, was bedeutet, daß er als Anhaltspunkt zum Verständnis der physikalischen Entstehungsbedingungen verwendet werden kann.
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References
Basso R, Dal Negro A, Della Diusta A, Rossi G (1979) Fe/Mg distribution in the olivines of ultramahc nodules from Assab (Ethiopia). N Jb Min Mh 5: 197–202
——Comin-Chiaramonti P, Della Giusta A, Flora O (1984) Crystal chemistry of four Mg-Fe-Al-Cr spinels from the Balmuccia peridotite (Western Italian Alps). N Jb Min Abh 150: 1–10
Blessing RH, Coppens P, Becker P (1972) Computer analysis of step-scanned X-ray data. J Appl Cryst 7: 488–492
Colby JW (1972) A computer program for quantitative electron microprobe analysis. Bell Telephone Laboratories Inc, Allentown, Pennsylvania.
Comin-Chiaramonti P, Demarchi G, Girardi VAV, Princivalle F, Sinigoi S (1986) Evidence of mantle metasomatism and heterogeneity from peridotite inclusions of northeast Brazil and Paraguay. Earth Planet Sci Letters 77: 203–217
Cundari A, Dal Negro A, Piccirillo EM, Della Giusta A, Secco L (1986) Intracrystalline relationships in olivine, orthopyroxene, clinopyroxene and spinel from a suite of spinel lherzolite xenoliths from Mt. Noorat, Victoria, Australia. Contrib Mineral Petrol 94: 523–532
Dal Negro A, Carbonin S, Domeneghetti C, Molin GM, Cundari A, Piccirillo EM (1984) Crystal chemistry and evolution of the clinopyroxene in a suite of high pressure ultramafic nodules from the Newer Volcanics of Victoria, Australia. Contrib Mineral Petrol 86: 221–229
Della Giusta A, Princivalle F, Carbonin S (1986) Crystal chemistry of a suite of natural Cr-bearing spinels with 0.15 ⩽ Cr ⩽ 1.07. N Jb Min Abh 155: 319–330
Ellis DJ (1976) High pressure cognate inclusions in the Newer Volcanics of Victoria. Contrib Mineral Petrol 58: 149–180
Frey FA, Green DH (1974) The mineralogy, geochemistry and origin of lherzolite inclusions in Victoria basanites. Geochim Cosmochim Acta 38: 1023–1059
Hafner S (1960) Metalloxide mit Spinellstruktur. Schw Mineral Petrol Mitt 40: 208–240
Hill RJ, Craig JR, Gibbs GV (1979) Systematics of the spinel structure type. Phys Chem Min 4: 317–339
Irving AJ (1974) Pyroxene-rich ultramafic xenoliths in the Newer basalts of Victoria, Australia. N Jb Min Abh 120: 147–167
Lindsley DH (1976) The crystal chemistry and structure of oxide minerals as exemplified by the Fe-Ti oxides. In:Rumble D III (ed) Oxide minerals, Mineral Soc of America, Short Course Notes, Vol 3: 1–60
O'Neill HStC, Navrotsky A (1983) Simple spinels: crystallographic parameters, cation radii, lattice energies, and cation distribution. Amer Mineral 68: 181–194
Ottonello G, Piccardo GB, Joron JL, Treuil M (1978a) Evolution of the upper mantle under the Assab Region (Ethiopia): suggestions from petrology and geochemistry of tectonitic ultramafic xenoliths and host basaltic lavas. Geol Rund 67-2: 547–575
——Piccardo GB, Mazzucotelli A, Cimmino F (1978b) Clinopyroxene-orthopyroxene major and rare earth element partitioning in spine] peridotite xenoliths from Assab (Ethiopia). Geochim Cosmochim Acta 42:1817–1828
—— (1980) Rare earth abundances and distribution in some spinel peridotite xenoliths from Assab (Ethiopia). Geochim Cosmochim Acta 44: 1885–1901
Piccardo GB, Ottonello G (1978) Partial melting effects on coexisting mineral compositions in upper mantle xenoliths from Assab (Ethiopia). Rendiconti SIMP 34: 499–526
Princivalle F, Secco L (1985) Crystal Structure Refinement of 13 Olivines in the Forsterite-Fayalite Series from Volcanic Rocks and Ultramafic Nodules. Tschermaks Min Petr Mitt 34: 105–115
——Secco L, Demarchi G (1989) Crystal chemistry of a clinopyroxene series of ultrafemic xenoliths from North-Eastern Brazil. Contrib Mineral Petrol 101: 131–135
Secco L (1988) Crystal-chemistry of high-pressure clinopyroxene from spinel lherzolite nodules: Mts. Leura and Noorat Suites, Victoria, Australia. Mineral Petrol 39: 175–185
Sinigoi S, Comin-Chiaramonti P, Demarchi G, Siena F (1983) Differentiation of partial melts in the mantle: evidence from the Balmuccia Peridotite, Italy. Contrib Mineral Petrol 82: 351–359
Urusov VS (1983) Interaction of cation on octahedral and tetrahedral sites in simple minerals. Phys Chem Min 9: 1–5
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Princivallel, F., Della Giusta, A. & Carbonin, S. Comparative crystal chemistry of spinels from some suites of ultramafic rocks. Mineralogy and Petrology 40, 117–126 (1989). https://doi.org/10.1007/BF01164322
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DOI: https://doi.org/10.1007/BF01164322