Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 6
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

The contributions of the members of the Department of Geochemistry, Mineralogy and Petrology, University of Warsaw, to the study of the chevkinite-group of minerals (CGM) are described. The range of research topics includes: (i) geochemical and mineralogical studies of natural occurrences of the group, and attempts to relate their chemical composition to host lithology; (ii) detailed analysis of the hydrothermal alteration of CGM in various settings, with the aim of understanding element redistribution and the potential implications for ore formation. An ongoing series of high P-T experiments is providing quantitative information on the pressures, temperatures and melt water conditions under which the alteration assemblages have formed. Various spectroscopic techniques are being used to determine the structure of the CGM and to identify cation distribution in the structures.
Go to article

Authors and Affiliations

Ray Macdonald
1 2
Bogusław Bagiński
1

  1. University of Warsaw, Faculty of Geology, Department of Geochemistry, Mineralogy and Petrology, Żwirki i Wigury 93, 02-089 Warszawa, Poland
  2. Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
Download PDF Download RIS Download Bibtex

Abstract

Compositional and textural data are presented for zircon, secondary Zr-silicates, catapleiite and elpidite in a peralkaline granite from the Ilímaussaq complex, south Greenland. The zircon is essentially stoichiometric, with (Zr + Hf + Si) = 1.96–1.98 a.p.f.u. The secondary Zr-silicates show a wide range of Zr/Si atomic ratios (0.13–0.79). The catapleiite varies from close to stoichiometric to a Na-depleted type showing cation deficiency (5.2–5.8 a.p.f.u.). Elpidite shows similar variations (7.2–9.0 a.p.f.u.). Textural relationships between the Zr phases are interpreted to show that magmatic zircon interacted with hydrous fluids exsolved from the magma to form the secondary Zr-silicates. Formation of catapleiite was late‑magmatic, in equilibrium with a Na-Sibearing fluid. This was followed by the crystallization of elpidite, the fluid having a different Na/Si ratio. Both catapleiite and elpidite experienced Na-loss during late-stage hydrothermal alteration.
Go to article

Authors and Affiliations

Małgorzata Cegiełka
1 2
Bogusław Bagiński
1
Ray Macdonald
1 3
Harvey E. Belkin
4
Jakub Kotowski
1
Brian G.J. Upton
5

  1. Department of Geochemistry, Mineralogy and Petrology, Faculty of Geology, University of Warsaw, ul. Żwirki i Wigury 93, 02-089 Warsaw, Poland
  2. Institute of Geological Sciences, Polish Academy of Sciences, Research Centre in Warsaw, ul. Twarda 51/55, 00-818 Warsaw, Poland
  3. Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
  4. 11142 Forest Edge Drive, Reston, VA 20190, USA
  5. Grant Institute, University of Edinburgh, James Hutton Rd., Edinburgh EH9 3FE, UK
Download PDF Download RIS Download Bibtex

Abstract

A peralkaline granite of the Ilímaussaq Complex, South Greenland, contains the rare mineral henrymeyerite [(Ba0.92Na0.05Ca0.03)1.0(Ti6.87Fe2+1.04Nb0.03)7.9O16], a low-Fe Ba titanate [(Ba0.74Ca0.02Na0.05)0.8 (Ti4.9oFe2+0.15 Nb0.04)5.1O11], and an unidentified Ba titanosilicate. Both titanates show the coupled substitution 2Na+ + Si4+ → Ba2+ + Ti4+. The minerals are present as tiny crystals fringing ilmenite inclusions in an amphibole crystal and are thought to have formed during the hydrothermal stage of the granite’s evolution.
Go to article

Authors and Affiliations

Małgorzata Cegiełka
1 2
Bogusław Bagiński
1
Ray Macdonald
1 3
Beata Marciniak-Maliszewska
1
Marcin Stachowicz
1

  1. Department of Geochemistry, Mineralogy and Petrology, Faculty of Geology, University of Warsaw, ul. Żwirki i Wigury 93, 02-089 Warsaw, Poland
  2. Institute of Geological Sciences, Polish Academy of Sciences, Research Centre in Warsaw,Twarda 51/55, 00-818 Warsaw, Poland
  3. Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
Download PDF Download RIS Download Bibtex

Abstract

The chevkinite group of minerals are REE,Ti-silicates increasingly recognized as widespread accessory phases in a wide range of igneous and metamorphic parageneses. Members of the group are here recorded from five localities in Poland: a two-pyroxene andesite from the Kłodzko-Złoty Stok intrusion, a trachyandesite intrusion north of the Pieniny Mountains, a rapakivi-type granite from the Krasnopol intrusion, an anorthosite from the Suwałki Anorthosite Massif, and nepheline syenite from the Ełk syenite massif. Specific members found are chevkinite-(Ce), perrierite-(Ce) and, potentially, the Al-dominant analogue of perrierite-(Ce). The case is made that chevkinite-group minerals will, through systematic investigation, be found in a wide range of Polish igneous and metamorphic rocks.

Go to article

Authors and Affiliations

Krzysztof Nejbert
Bogusław Bagiński
Jakub Kotowski
Petras Jokubauskas
Edyta Jurewicz
Ray Macdonald

This page uses 'cookies'. Learn more