| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Journal of Petrology Volume 42 Number 10 Pages 1813-1843 2001
© Oxford University Press 2001
Almandine Garnet in Calc-alkaline Volcanic Rocks of the Northern Pannonian Basin (Eastern–Central Europe): Geochemistry, Petrogenesis and Geodynamic Implications
1DEPARTMENT OF PETROLOGY AND GEOCHEMISTRY, EÖTVÖS UNIVERSITY, H-1088 BUDAPEST, MÚZEUM KRT. 4/A, HUNGARY
2SCHOOL OF EARTH SCIENCES, BIRKBECK COLLEGE, MALET STREET, LONDON WC1E 7HX, UK
3DEPARTMENT OF GEOLOGY, ROYAL HOLLOWAY UNIVERSITY OF LONDON, EGHAM TW20 0EX, UK
4PETROLOGY GROUP, FACULTY OF EARTH SCIENCES, UNIVERSITY OF UTRECHT, BUDAPESTLAAN 4, 3584 CD UTRECHT, THE NETHERLANDS
Almandine garnet-bearing andesites and dacites occur frequently in the Neogene calc-alkaline volcanic series of the northern Pannonian Basin (Hungary and Slovakia). They were erupted during the early stage of volcanism and occur along major tectonic lineaments. On the basis of petrographic and geochemical characteristics, garnets from these rock types are classified into (1) primary phases, (2) composite minerals containing xenocrystic cores and magmatic overgrowths and (3) garnets derived from metamorphic crustal xenoliths. Coexisting phenocrysts of primary garnets include Ca-rich plagioclase, hornblende (magnesiohastingsite to tschermakite) and/or biotite. The primary garnets have high CaO (>4 wt %) and low MnO contents (<3 wt %). They have strongly light rare earth element depleted patterns and are enriched in heavy rare earth elements. Negative Eu anomalies occur only in garnets in the more silicic host rocks. 
18O values for primary garnets are 6·1–7·3
, whereas composite garnets have elevated 18O values (>8). Chemical compositions of the primary garnets and coexisting minerals suggest that they crystallized at high pressures (7–12 kbar) and temperatures (800–940°C) from mantle-derived magmas. Sr–Nd isotopic compositions of their host rocks and O isotopic values of the garnets are consistent with two-component mixing between mantle-derived magma and lower-crustal metasedimentary material. The garnet-bearing silicic magmas were erupted during extension of the Pannonian Basin and the tensional stress field may have enhanced their fast ascent from lower-crustal depths, allowing preservation of early-formed almandine phenocrysts.
KEY WORDS: almandine; garnet; calc-alkaline volcanism; geochemistry; Pannonian Basin
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  E. Bali, Z. Zajacz, I. Kovacs, CS. Szabo, W. Halter, O. Vaselli, K. Torok, and R. J. Bodnar A Quartz-bearing Orthopyroxene-rich Websterite Xenolith from the Pannonian Basin, Western Hungary: Evidence for Release of Quartz-saturated Melts from a Subducted Slab J. Petrology, March 1, 2008; 49(3): 421 - 439. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Harangi, H. Downes, M. Thirlwall, and K. Gmeling Geochemistry, Petrogenesis and Geodynamic Relationships of Miocene Calc-alkaline Volcanic Rocks in the Western Carpathian Arc, Eastern Central Europe J. Petrology, December 1, 2007; 48(12): 2261 - 2287. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 V. Cvetkovic, G. Poli, G. Christofides, A. Koroneos, Z. Pecskay, K. Resimic-Saric, and V. Eric The Miocene granitoid rocks of Mt. Bukulja (central Serbia): evidence for pannonian extension-related granitoid magmatism in the northern Dinarides European Journal of Mineralogy, July 1, 2007; 19(4): 513 - 532. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Harangi, H. Downes, and I. Seghedi Tertiary-Quaternary subduction processes and related magmatism in the Alpine-Mediterranean region Geological Society, London, Memoirs, January 1, 2006; 32(1): 167 - 190. [Abstract] [PDF]
|
|
|
|
 |
|
 H. Kawabata and N. Takafuji Origin of garnet crystals in calc-alkaline volcanic rocks from the Setouchi volcanic belt, Japan Mineralogical Magazine, December 1, 2005; 69(6): 951 - 971. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. BERGER, O. FEMENIAS, N. COUSSAERT, and D. DEMAIFFE Magmatic garnet-bearing mafic xenoliths (Puy Beaunit, French Massif Central): P-T path from crystallisation to exhumation European Journal of Mineralogy, October 1, 2005; 17(5): 687 - 701. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y.-H. JIANG, H.-F. LING, S.-Y. JIANG, H.-H. FAN, W.-Z. SHEN, and P. NI Petrogenesis of a Late Jurassic Peraluminous Volcanic Complex and its High-Mg, Potassic, Quenched Enclaves at Xiangshan, Southeast China J. Petrology, June 1, 2005; 46(6): 1121 - 1154. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Vielzeuf, M. Veschambre, and F. Brunet Oxygen isotope heterogeneities and diffusion profile in composite metamorphic-magmatic garnets from the Pyrenees American Mineralogist, February 1, 2005; 90(2-3): 463 - 472. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. PROUTEAU and B. SCAILLET Experimental Constraints on the Origin of the 1991 Pinatubo Dacite J. Petrology, December 1, 2003; 44(12): 2203 - 2241. [Abstract] [Full Text] [PDF]
|
|