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Evidence of a water-rich silica gel state during the formation of a simple pegmatite

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Version 2 2023-06-23, 11:03
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journal contribution
posted on 2023-06-23, 11:03 authored by R Thomas, Paul DavidsonPaul Davidson
This study reports the discovery of inclusions, which are inferred to represent trapped primary silicate gels, in simple pegmatites genetically connected to the Precambrian Rønne granite of Bornholm Island, Denmark. These inclusions are randomly associated with more typical melt and alkali-carbonate-rich and bicarbonate-rich fluid inclusions. Their relationship to the latter and to the formation of the pegmatite bodies is discussed. The silicate gel inclusions become increasingly common towards the quartz cores of the pegmatites, and are considered to demonstrate increasing water and alkali carbonate concentrations in the pegmatite-forming liquid, and an accompanying tendency for sol/gel formation. This discovery may have important implications for the formation of the quartz cores of pegmatites. The possible origin of the alkali-carbonate concentrations in pegmatite-forming fluids is also briefly discussed.

History

Publication title

Mineralogical Magazine

Volume

76

Issue

7

Article number

7

Number

7

Pagination

2785-2801

ISSN

0026-461X

Department/School

CODES ARC

Publisher

Mineralogical Society

Publication status

  • Published

Rights statement

Copyright 2012 The Mineralogical Society

Repository Status

  • Open

Socio-economic Objectives

280107 Expanding knowledge in the earth sciences