Serpentinites of the Ural: Mineralogical Features, Petrophysical Properties and Subduction Processes

Abstract

The article presents the results of study of composition, structure and properties of three genetic types of serpentinites from Ural: developed by chromite-bearing ultrabasic rocks, by metamorphic zones of carbonate rocks and within the zone of weathering of ultrabasic rocks. The samples were selected from deposits, located along the Main Ural Faultthe Paleozoic subduction zone (named GUR). Peculiarities of microstructure, chemical composition and properties of serpentinites formed in different geological conditions were investigated and their comparative study was held. Three groups of serpentinites with oriented and non-oriented structure, which formed by different protholites, were devided: mantle, lithosphere and crust.

Listvenite Formation During Mass Transfer into the Leading Edge of the Mantle Wedge: Initial Results from Oman Drilling Project Hole BT1B

“…Spherulites form during devitrification of amorphous opal as well as rhyolite glass, so Falk and Kelemen (2015) and the Shipboard Science Party (Kelemen, Matter, et al, 2020) interpreted these as replacing opal, which would have been among the earliest SiO 2 minerals to form in many of the listvenites. Importantly, opal is commonly found in other listvenites and serpentine-magnesite associations worldwide (Abu-Jaber & Kimberley, 1992;Aftabi & Zarrinkoub, 2013;Akbulut et al, 2006;Arisi Rota et al, 1971;Barnes et al, 1973;Beinlich et al, 2010, Borojević Šoštarić et al, 2014Boschi et al, 2009;Ece Öi et al, 2005;Jurković et al, 2012;Lacinska & Styles, 2013;Lapham, 1961;Oskierski, Bailey, et al, 2013;Posukhova et al, 2013;Quesnel et al, 2016;Searston, 1998;Ulrich et al, 2014;Zarrinkoub et al, 2005). Vein types cutting this fine-grained matrix generally record a progression from texturally early, antitaxial magnesite veins-some with cores of hematite + other Fe-oxides (Figure 6)-and related, early Fe-oxide veins, to syntaxial dolomite veins and carbonate-quartz veins, and lastly to syntaxial calcite veins.…”