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The fluid regime of crystallization of water-saturated granitic and pegmatitic magmas : A physicochemical analysis. / Smirnov, S. Z.
In: Russian Geology and Geophysics, Vol. 56, No. 9, 01.09.2015, p. 1292-1307.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - The fluid regime of crystallization of water-saturated granitic and pegmatitic magmas
T2 - A physicochemical analysis
AU - Smirnov, S. Z.
PY - 2015/9/1
Y1 - 2015/9/1
N2 - Miarolitic granite pegmatites are a unique natural object that makes it possible to study magmatic processes that lead to the formation of ore-forming media and systems. This paper summarizes modern views on phase transformations in aqueous silicate systems at parameters close to those of the transition from magmatic to hydrothermal crystallization. Comparison of phase diagrams and the results of study of pegmatite-forming media permits making conclusions about the crystallization of the water-saturated magmas of miarolitic granite pegmatites. The fluid regime of aqueous granite systems of simple composition, not enriched in fluxing components, is determined mainly by magma degassing or the supply of volatiles with flows of transmagmatic fluids. These processes cause the separation of essentially carbon dioxide or essentially hydrous fluid. During the evolution of such magmas, crystallization from silicate melt is separated in PT-space and, possibly, in time from the crystallization from aqueous or mixed carbon dioxide-aqueous super- and subcritical solutions. The evolution of chambers of water-saturated granitic and pegmatitic magma enriched in F, B, and alkali metals presupposes the formation of a heterogeneous mineral-forming medium in which crystallization occurs in the magmatic melt at high-temperature stages; as temperature decreases, crystallization can proceed in hydrous fluid, hydrosilicate, and/or hydrosaline liquids simultaneously. Hydrothermal crystallization can also take place in a heterogeneous medium consisting of aqueous solutions of different salinities and vapor or vapor-carbon dioxide gas mixture. The relationship between different fluid regimes during the evolution of volatile-saturated granitic and pegmatitic magmas determines the variety of postmagmatic rocks accompanying granite massifs.
AB - Miarolitic granite pegmatites are a unique natural object that makes it possible to study magmatic processes that lead to the formation of ore-forming media and systems. This paper summarizes modern views on phase transformations in aqueous silicate systems at parameters close to those of the transition from magmatic to hydrothermal crystallization. Comparison of phase diagrams and the results of study of pegmatite-forming media permits making conclusions about the crystallization of the water-saturated magmas of miarolitic granite pegmatites. The fluid regime of aqueous granite systems of simple composition, not enriched in fluxing components, is determined mainly by magma degassing or the supply of volatiles with flows of transmagmatic fluids. These processes cause the separation of essentially carbon dioxide or essentially hydrous fluid. During the evolution of such magmas, crystallization from silicate melt is separated in PT-space and, possibly, in time from the crystallization from aqueous or mixed carbon dioxide-aqueous super- and subcritical solutions. The evolution of chambers of water-saturated granitic and pegmatitic magma enriched in F, B, and alkali metals presupposes the formation of a heterogeneous mineral-forming medium in which crystallization occurs in the magmatic melt at high-temperature stages; as temperature decreases, crystallization can proceed in hydrous fluid, hydrosilicate, and/or hydrosaline liquids simultaneously. Hydrothermal crystallization can also take place in a heterogeneous medium consisting of aqueous solutions of different salinities and vapor or vapor-carbon dioxide gas mixture. The relationship between different fluid regimes during the evolution of volatile-saturated granitic and pegmatitic magmas determines the variety of postmagmatic rocks accompanying granite massifs.
KW - Fluid
KW - Fluid and melt inclusions
KW - Granite pegmatites
KW - Silicate-water
UR - http://www.scopus.com/inward/record.url?scp=84939600330&partnerID=8YFLogxK
U2 - 10.1016/j.rgg.2015.08.006
DO - 10.1016/j.rgg.2015.08.006
M3 - Article
AN - SCOPUS:84939600330
VL - 56
SP - 1292
EP - 1307
JO - Russian Geology and Geophysics
JF - Russian Geology and Geophysics
SN - 1068-7971
IS - 9
ER -
ID: 25762657