FORMATION SERIES IN OROGENIC VOLCANIC BELTS: IMPLICATIONS FOR PALEOENVIRONMENTS
A.M. Kurchavov
Interdepartmental Committee for Petrography, RAS Department of Earth Sciences, 35 Staromonetny per., Moscow, 119017, Russia
Keywords: Formation series, volcanism, orogenic belts, paleoreconstructions
Pages: 1364-1372
Subsection: GEODYNAMICS
Abstract
Orogenic volcanic belts form in various tectonic settings including active continental margins, mature island arcs upon continental crust, or zones of continental collision. Orogenic belts of all environments share common evolution trends and go through the same stages of volcanism changing progressively in composition from basalt-andesite or successively differentiated basalt-andesite-dacite-rhyolite series (early orogenic stage) to mostly rhyodacite-rhyolite series (middle stage), and finally to late orogenic high-alkali mono- or bimodal series. Each evolution stage of orogenic belts produced a general lateral sequence of rock compositions from low-K rocks in the belt front to high-K and alkalic varieties at the back. Comprehensive investigation into formation series and related rock chemistry variations in space and time can provide clues to paleogeodynamic environments of volcanism associated with orogenic belts.
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