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 (8) Citing Articles via Google Scholar Google Scholar Articles by Brizi, E. Articles by Zanazzi, P. F. Search for Related Content GeoRef GeoRef Citation

Experimental study of intracrystalline Fe²⁺-Mg exchange in three augite crystals: Effect of composition on geothermometric calibration

¹ Dipartimento di Scienze della Terra, Universita’ di Perugia, Perugia, Italia
² Dipartimento di Mineralogia e Petrologia, Universita’ di Padova, Padova, Italia

Correspondence: ^* E-mail: zanazzi{at}unipg.it

Three augite crystals with differing chemical compositions [Fonualei dacite lava flow, Tonga (Fon39) (En₃₆Fs₂₇Wo₃₇), Alicudi andesitic dike (KC) (En₄₆Fs₁₁Wo₄₃), and Vulcano basalt dike (PD30) (En₄₂Fs₁₂Wo₄₆)] were equilibrated over the temperature range 700–1100 °C through both disordering and ordering reactions ("reversal technique") and then quenched at room temperature. Following each experiment, the partitioning of Fe²⁺-Mg between M1 and M2 sites of clinopyroxene was determined by single-crystal structure refinement. The Fe²⁺-Mg partitioning data of the order-disorder reaction, Fe²⁺_M2 + Mg_M1 = Fe²⁺_M1 + Mg_M2, in terms of the partition coefficient K_D{= [(Fe²⁺_M1)(Mg_M2)/ (Fe²⁺_M2)(Mg_M1)]}, were then used to calibrate the following geothermometric equations:

respectively for Fon39, KC, and PD30. A situation in which thermodynamic parameters depend on crystal composition may be envisaged. It should be noted that such dependence is essentially controlled by the (Ca+Na) and R³⁺ contents of the clinopyroxene. On the basis of compositional dependence, the following geothermometric equation is proposed:

This article has been cited by other articles:

				H. L. Lledo and D. M. Jenkins Experimental Investigation of the Upper Thermal Stability of Mg-rich Actinolite; Implications for Kiruna-Type Iron Deposits J. Petrology, February 1, 2008; 49(2): 225 - 238. [Abstract] [Full Text] [PDF]

				J. Driscall, D. M. Jenkins, M. D. Dyar, and K. N. Bozhilov Cation ordering in synthetic low-calcium actinolite American Mineralogist, May 1, 2005; 90(5-6): 900 - 911. [Abstract] [Full Text] [PDF]

				E. Brizi, G. Molin, P. F. Zanazzi, and M. Merli Ordering kinetics of Mg-Fe2+ exchange in a Wo43En46Fs11 augite American Mineralogist, March 1, 2001; 86(3): 271 - 278. [Abstract] [Full Text] [PDF]