Mineral chemistry, petrogenesis and P–T conditions of formation of harzburgitic peridotites from south of Birjand, Eastern Iran

Neogene to Present paleostress field in Eastern Iran (Sistan belt) and implications for regional geodynamics

“…The Sistan belt displays a complex imbrication of thrust sheets, with rocks of various origins, variably deformed and metamorphosed. Peridotites, serpentinites, gabbros, and leucogabbros, dolerites, basalts, and radiolarites represent remnants of the lithosphere of the Sistan oceanic basin and its pelagic sedimentary cover [ Camp and Griffis , ; Moazzen et al ., ]. Biostratigraphic dating of radiolarites yielded early Aptian to late Albian ages [ Babazadeh and De Wever , ].…”

The North Sistan orogen (Eastern Iran): Tectono-metamorphic evolution and significance within the Tethyan realm

“…Associated 1058 depleted harzburgite is interpreted as residual mantle, following melting. However, depending 1059 on the proxy used (i.e., #Cr in spinel, Ti in clinopyroxene or trace element modelling), 1060 contrasting degrees of partial melting were proposed to produce these N-MORB and/or the 1061 residual depleted harzburgite, from low (Zarrinkoub et al, 2012a) to high (Moazzen et al, 1062(Moazzen et al, 2006 and in one or several melting stages (Saccani et al, 2010). Some E-MORB were 1063 interpreted as coming from an interaction between the DMM and an enriched deeper source 1064 (Saccani et al, 2010;Zarrinkoub et al, 2012a), whereas rare, supra-subduction zone affinity 1065 magmatic rocks were interpreted as produced by a DMM source fluxed by subduction-derived 1066 fluids (Saccani et al, 2010;Zarrinkoub et al, 2012a).…”

“…The Sistan belt was mapped at the 1:50.000 scale as part of an extensive regional 110 mapping and mineral exploration program with the Geological and Mineral Survey of Iran. 111 Based on lithostratigraphic (15 logs) and tectonic (three local cross-sections) investigations, 112 Tirrul et al (1983) Petrological and geochemical studies on the ophiolite (Delaloye and 150 Desmons, 1980;Moazzen et al, 2006;Saccani et al, 2010;Zarrinkoub et al, 2012a) show that 151 its mantle section mostly consists of harzburgite (less than 5% of clinopyroxene), affected by 152 variable degrees of serpentinisation. The crustal section dominantly comprises N-MORB 153 gabbros and basalts and rarer E-MORB basalts, respectively attributed to ridge-type 154 magmatism (~5-20% partial melting of DMM) and to an environment where the DMM is mixed 155 with an enriched source (e.g., interaction with a hot-spot; Saccani et al, 2010).…”