Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (10) Citing Articles via Google Scholar Google Scholar Articles by Schmidt, M. W. Articles by Poli, S. Search for Related Content GeoRef GeoRef Citation

Magmatic Epidote

Institute for Mineralogy and Petrology ETH 8092 Zürich, Switzerland

Stefano Poli

Dipartimento Scienze della Terra Via Botticelli 23 Universitàdegli Studi di Milano 20133 Milano, Italy

The first 20% of the full text of this article appears below.

	INTRODUCTION

 
Epidote was first recognized as a magmatic mineral in the alpine Bergell tonalite by Cornelius (1915). Field observations and microscopic textures let Cornelius to conclude "... the only possibility is, that epidote is a primary mineral in our tonalite, crystallizing early from the magma, i.e., before (in part also contemporaneous with) biotite" (translated from German, Cornelius (1915), p. 170). This knowledge disappeared and for the following 70 years, epidote and zoisite were categorized as metamorphic minerals. The petrologic significance of magmatic epidote was then rediscovered when Zen and Hammarstrom (1984) identified epidote as an important magmatic constituent of intermediate calc-alkaline intrusives in plutons of the North American Cordillera. Zen and Hammarstrom (1984) also suggested that epidote indicates a minimum intrusive pressure of about 0.5 to 0.6 GPa. Subsequently, magmatic epidote was described from many granodioritic to tonalitic plutons, but also from monzogranite (e.g., Leterrier 1972), dikes of dacitic composition (Evans and Vance 1987), and orbicular diorite (Owen 1991, 1992). Furthermore, epidote was not only recognized in crystallizing plutons or dikes but also in high pressure migmatites and pegmatites derived from eclogites (Nicollet et al. 1979; Franz and Smelik 1995).

The role of epidote during magmatic crystallization is relatively well understood, and crystallization temperatures and sequences involving epidote in intermediate magmas (granodiorite-tonalite-trondhjemite, TTG) are experimentally determined and confirmed from natural intrusives. In contrast, little attention is directed towards the inverse process, i.e., melting of epidote bearing lithologies. Epidote is omnipresent in eclogite of intermediate temperature (Enami et al. 2004) and denominates three subfacies (i.e., epidote-blueschist, epidote-amphibolite, and epidote-eclogite facies). Indeed the epidote-amphibolite facies intersects the wet granite solidus near 0.5 GPa at 680°C, defining the pressure above which epidote may be present during melting processes. Experiments on . . . [Full Text of this Article]

This article has been cited by other articles:

				S. Giorgis, W. McClelland, A. Fayon, B. S. Singer, and B. Tikoff Timing of deformation and exhumation in the western Idaho shear zone, McCall, Idaho Geological Society of America Bulletin, September 1, 2008; 120(9-10): 1119 - 1133. [Abstract] [Full Text] [PDF]

				G. Franz and A. Liebscher Physical and Chemical Properties of the Epidote Minerals-An Introduction- Reviews in Mineralogy and Geochemistry, January 1, 2004; 56(1): 1 - 81. [Full Text] [PDF]

				S. Poli and M. W. Schmidt Experimental Subsolidus Studies on Epidote Minerals Reviews in Mineralogy and Geochemistry, January 1, 2004; 56(1): 171 - 195. [Full Text] [PDF]

				D. Frei, A. Liebscher, G. Franz, and P. Dulski Trace Element Geochemistry of Epidote Minerals Reviews in Mineralogy and Geochemistry, January 1, 2004; 56(1): 553 - 605. [Full Text] [PDF]

				J. Morrison Stable and Radiogenic Isotope Systematics in Epidote Group Minerals Reviews in Mineralogy and Geochemistry, January 1, 2004; 56(1): 607 - 628. [Full Text] [PDF]