One view of the metamorphic subduction system supposes that coupled deformation and prograde/metasomatic reaction between the chemically enriched slab and the depleted mantle wedge promotes the formation of complexly hybridized lithologies along the slab/mantle interface. This type of model is based upon direct observations of the structure and petrology of high-P/T metamorphic complexes (e.g.,...

Neoproterozoic and Palaeozoic rocks of the Mérida Massif (SW Iberia) have been grouped into tectonostratigraphic units. Each unit is separated from rest ones by either crustal-scale thrusts and/or extensional detachments. The lowermost (Magdalena Gneisses; lower plate) has continental crust affinity, below a mafic-ultramafic ensemble, referred to as Ophiolite (suture zone). Serie Negra Group co...

Investigation of parent magma evolution and origin chromites in Cheshmeh-Bid, ophiolite Neyriz, Fars

The Isua Supracrustal Belt, Greenland, of Early Archean age (3.81-3.70 Ga) represents the oldest crustal segment on Earth. Its complex lithology comprises an ophiolite-like unit and volcanic rocks reminiscent of boninites, which tie Isua supracrustals to an island arc environment. We here present zinc (Zn) isotope compositions measured on serpentinites and other rocks from the Isua supracrustal...

A Helly-type theorem for diameter provides a bound on the of intersection finite family convex sets in $\mathbb{R}^d$ given some information all sufficiently small subfamilies. We prove fractional and colorful versions long-standing conjecture by Bárány, Katchalski, Pach. also show that Minkowski norm admits an exact if only its unit ball is polytope version those do. Finally, we theorems prope...

We report Li isotopic compositions of olivine from the mantle sequence of the Luobusa ophiolite, southern Tibet. The olivine in the Luobusa ophiolite has Li concentrations from ~0.1 to 0.9 ppm and a broad range of δ(7)Li (+14 to -20‰). An inverse correlation of Li concentration and δ(7)Li in olivine from harzburgite suggests recent diffusive ingress of Li into the rock. Olivine from dunite enve...

The Bi’r Umq-Nakasib suture zone, 5-65 km wide and over 600 km long, consists of highly deformed ophiolite nappes and metavolcanic, metasedimentary, and intrusive rocks contained in one of the longest ophiolite-decorated shear zones in the Arabian-Nubian Shield. The rocks originated in a variety of juvenile oceanic environments and include assemblages formed in mid-ocean-ridge, subduction-zone,...

Chromite is widely distributed in the east and southeast of Afghanistan, especially in Logar Province. Chromite mineralization is podiform-type and is hosted in the stratigraphically lowest ultramafic rocks of the Logar Ophiolite Complex. This ophiolite complex represents a remnant of an early Cretaceous oceanic crust that was thrusted over a late Permian to Mid-Jurassic platform-type sequence ...