The low-pressure partial-melting behaviour of natural boron-bearing metapelites from the Mt. Stanford area, central Australia

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doi: 10.1007/s00410-004-0577-z
Authors:Spicer, Esmé M.; Stevens, Gary; Buick, Ian S.
Author Affiliations:Primary:
Stellenbosch University, Geology Department, Matieland, South Africa
Other:
La Trobe University, Australia
Volume Title:Contributions to Mineralogy and Petrology
Source:Contributions to Mineralogy and Petrology, 148(2), p.160-179. Publisher: Springer International, Heidelberg-New York, International. ISSN: 0010-7999
Publication Date:2004
Note:In English. 57 refs.; illus., incl. 8 tables, 2 plates
Summary:The ∼ 300 MPa partial melting behaviour of four metapelites collected from the highest grade rocks occurring below the anatectic zone of the Mt. Stafford area, Arunta Inlier, central Australia is examined. In this area, metasediments are interpreted to have undergone partial melting within the andalusite stability field; possibly as a result of a lowering of the metapelite solidus by the presence of boron in the rocks. Two of the samples were two mica metapelites (MTS70 and MTS71). These both contained significant quantities of tourmaline and were thus boron enriched. The other two samples are biotite metapelites. One of these rocks contains only a trace of tourmaline (MTS8) and the other is tourmaline free (MTS7). Muscovite was stable to above 750°C due to the incorporation of Ti, phengitic and possibly F components into its structure. Between 750 and 800°C, muscovite melted out completely via a coupled muscovite + biotite fluid-absent incongruent reaction. Tourmaline was partially consumed in this reaction, with the elbaitic component being preferentially consumed. Under the fluid-absent conditions of this study, tourmaline is clearly a reactant in the partial melting process, but does not appear to shift the fluid-absent incongruent melting reactions markedly. In the tourmaline-rich two mica metapelites, tourmaline only disappears from the run products at a T above 850°C, where it coexisted with a substantial melt proportion. This appears to coincide with the point of maximum boron concentration in the melts. [G.L.B.]
Sections:Experimental mineralogy; Petrology
Subsections:Metamorphic rocks; Silicates
Subjects:Andalusite; Boron; Chemical composition; Electron probe data; Low pressure; Major elements; Metamorphic rocks; Metapelite; Metasedimentary rocks; Mineral assemblages; Mineral composition; Nesosilicates; Orthosilicates; Partial melting; Petrography; Phase equilibria; Pressure; Ring silicates; SEM data; Silicates; Spectra; Temperature; Textures; Tourmaline group; X-ray fluorescence spectra; Arunta Block; Australasia; Australia; Northern Territory Australia; Mount Stanford
Abstract Numbers:04M/4549
Record ID:2005064616
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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