specific elements (cr, al, ca, and si) and loss on ignition (loi) were used for semi-quantitative determination of the normative mineralogical composition of naturally occurring chromium ores in ophiolite complexes. by far the occurring ore minerals are complex both from the mineralogical and chemical viewpoints. the secondary minerals serpentine and cr-containing chlorite (kaemmererite) form n...

Two ancient asbestos mines, one near Karystos, Greece, and the other southeast of Mount Troodos, Cyprus, were located in what we now know to be ophiolite terrane. Evidence suggests that asbestos was discovered and utilized in Cyprus, perhaps as long as 5,000 years ago, for manufacture of cremation cloths, lamp wicks, hats, and shoes. Some of the adverse health effects of asbestos became known o...

Analysis of internal structures of the Brooks Range ophiolite at the three largest and well-exposed klippen reveals a NE-SW structural grain that may parallel the original axis of magmatism of a slow spreading marginal ocean basin. Sub-parallel directions of lattice·fabrics in olivine of mantle peridotite and shape fabrics in pyroxene and plagioclase of layered gabbro indicate that asthenospher...

Integration of data from field. geochemistry, and radiometric age invcstigations of the active Banda arc-Australia collision zonc (Banda orogen) and· the Jurassic Brooks Range ophiolite provide ncw constraints for the origin and emplacement of Oman-type ophiolites. These ophiolites arc characterized by ultramafic residuals and mafic products that arc chemically modified by "anous dcgrees of pan...

Structural field relations, petrologic and geochemical studies, and radiometric age aualysis of metamorphic rocks at the base of the Brooks Range ophiolite provide a record of the time, tectonic setting, and initial conditions of ophiolite emplacement during the Middle Jurassic western Brookian orogeny. The metamorphic sole of the Misheguk, Siniktanneyak, and Avan Hills ophiolite bodies is tran...

(40)Ar/(39)Ar dates of emplacement-related metamorphic rocks beneath the Samail ophiolite in Oman show that cooling to <525 degrees C occurred within approximately 1 million years of igneous crystallization of the ophiolite. This unexpectedly short time span and rapid cooling means that old, cold continental or oceanic lithosphere must have been adjacent to the ophiolite during spreading and th...

The Upper Jurassic Galice Formation and parts of its 164 to 162 Ma Josephine ophiolite basement, both of the western Klamath terrane (WKT) have been suggested to constitute lower grade equivalents of the Condrey Mountain Schist (CMS) . The high P/T CMS is exposed through a window within the Rattlesnake Creek terrane (RCT) which has been thrust westward over the WKT. The Ga lice-CMS correlation ...

The Ophiolite Terrane of the Southern Chewore Inliers is comprised of two related, but lithologicallyand geochemically-distinct groups. The Maunde Ophiolite Group comprises a suite of lithologies similar to those within Phanerozoic ophiolites. The Kaourera Island Arc Group contains a suite of silica-variable, extrusive lithologies similar to those within present-day island-arcs. Geochemical ana...

7 The Unst Ophiolite is the best exposed of a chain of early Ordovician ophiolites in the 8 Scottish Caledonides and is widely regarded as having formed in a supra-subduction zone 9 setting within the Iapetus Ocean. Reinterpretation of sheeted dykes suggests that it formed 10 as an oceanic core complex, presumably during subduction roll-back immediately prior to 11 obduction onto the Laurentian...