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Showing 1 to 20 of 47 for “"Ophiolite"”.
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Platinum-group element mineralisation in the Shetland ophiolite complex
The Shetland ophiolite complex exhibits the lower part of the definitive Penrose sequence, but chromitites from the Cliff locality contain levels of Pt and Pd which are unusual in ophiolites. Aspects of this mineralisation suggest both magmatic and hydrothermal concentration processes, although …
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THE TECTONIC EVOLUTION OF THE HATAY OPHIOLITE OF SOUTHEAST TURKEY
… to constrain rotations in the Hatay (Kizildag) ophiolite of southeast Turkey in the eastern Mediterranean region and to produce a tectonic model for its evolution. The ophiolite comprises part of a prominent chain of southern Neotethyan ophiolites that stretches from the Troodos ophiolite of …
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The petrology, geochemistry and structure of the plutonic rocks of the Oman ophiolite
The Oman Ophiolite represents a fragment of oceanic crust and upper mantle that was emplaced onto the Arabian continental margin during the late Cretaceous. An area of 3000km2, comprising the Haylayn and Rustaq Blocks, has been mapped and specific localities were investigated in order to examine …
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Geochemistry, structure, and tectonic evolution of the Eldivan ophiolite, Ankara Melange, central Turkey
<p>The Eldivan ophiolite, in the Ankara Mélange, represents the remnant of an ocean basin that developed in the İzmir-Ankara-Erzincan Ocean and collapsed the form the İzmir -Ankara-Erzincan suture zone (İAESZ) through continental block collision. Whole-rock and mineral geochemical evidence show …
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Determining timescales of natural carbonation of peridotite in the Samail Ophiolite, Sultanate of Oman
… investigated in the mantle layer of the Samail Ophiolite, Sultanate of Oman. Rates of ongoing, low-temperature CO2 uptake were estimated through 14C and 230Th dating of carbonate alteration products. Approximately 1-3 x 106 kg CO2/yr is sequestered in Ca-rich surface travertines and …
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Determining timescales of natural carbonation of peridotite in the Samail Ophiolite, Sultanate of Oman
… investigated in the mantle layer of the Samail Ophiolite, Sultanate of Oman. Rates of ongoing, low-temperature CO₂ uptake were estimated through ¹⁴C and ²³⁰Th dating of carbonate alteration products. Approximately 1-3 x 10⁶ kg CO₂/yr is sequestered in Ca-rich surface travertines and …
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Making oceanic plagiogranite bodies by thermal migration: evidence from the Agros transect, Troodos ophiolite, Cyprus
… at the sheeted dike-gabbro boundary of most ophiolites, represent highly differentiated compositions produced in a steady state temperature gradient of a spreading center melt lens via thermal migration. For this study, twelve samples were collected along a spatial transect from the uppermost …
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The primary structures and fabrics of the upper mantle and lower oceanic crust from ophiolite complexes
… of areas from the lower sequences of the Oman Ophiolite, the Troodos Ophiolite, Cyprus, and the Shetland Ophiolite have been studies in order to gain an understanding of the structural and kinematic history of the upper mantle and lowermost oceanic crust at accretionary margins. In all areas …
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Deciphering the signature of fluid/rock reactions in the lower oceanic crust: The Oman ophiolite analogue
… in the lower oceanic crust of the Semail ophiolite. Hole GT1A located in Wadi Gideah targeted a hydrothermal fault zone, recovering multiple deformed intervals throughout the whole section of layered gabbros. This study recognizes two main categories and a further 7 sub-categories of …
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The Sheeted Dyke-Gabbro Transition Zone: the Key to Unravelling the Palaeomagnetic Record of the Oman Ophiolite
The Oman ophiolite is a natural laboratory for the study of processes operating above a nascent subduction zone. It formed in the Late Cretaceous by supra-subduction zone spreading and shortly afterwards was emplaced onto the Arabian continental margin. Twelve massifs in the ophiolite expose …
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The metamorphic sheet and underlying volcanic rocks beneath the Semail ophiolite in the northern Oman mountains of Arabia
… structural analysis along the base of the Semail ophiolite thrust sheet in the northern Oman mountains has revealed a distinct and separate thrust sheet between the underlying marine sediments of the Hawasina Complex, and the overlying 12 km+ thick Semail ophiolite. This thrust sheet is termed the …
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Structural Re-orientation of Magmatic Fabrics and Layering in the Lower Oceanic Crust: Hole GT1, Wadi Tayin Massif, Samail Ophiolite
… Hole GT1 in the Wadi Tayin massif of the Oman ophiolite by the Oman Drilling Project to better constrain models of crustal accretion. The gabbro glacier model proposes that crystallized basalt flows down and away from the crystallization site to form the lower crust while the sheeted sill model …
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ΚΑΤΑΝΟΜΗ ΤΩΝ ΣΤΟΙΧΕΙΩΝ ΤΗΣ ΟΜΑΔΑΣ ΤΟΥ ΛΕΥΚΟΧΡΥΣΟΥ (PGE) ΚΑΙ ΤΟΥ ΧΡΥΣΟΥ ΣΕ ΧΡΩΜΙΤΙΚΑ ΜΕΤΑΛΛΕΥΜΑΤΑ ΚΑΙ ΠΕΤΡΩΜΑΤΑ ΤΟΥ ΟΦΙΟΛΙΘΙΚΟΥ ΣΥΜΠΛΕΓΜΑΤΟ...
… OF PLATINUM GROUP ELEMENTS IN VOURINOS OPHIOLITE COMPLEX REVEALED A SIGNIFICANT VARIATION IN THE COMPOSITION OF CHROMITE ORES AND HOST ROCKS,WHICH WAS CONSIDERED BY PREVIOUS AUTHORS TO BE VERY RESTRICTED. CHROMITE AND HOST ROCK GEOCHEMISTRY STUDY THROUGHOUT THE VOURINOS OPHIOLITE COMPLEX …
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Novel Insights into the Palaeomagnetism of Serpentinized Peridotites from the Troodos and Oman Ophiolites
… peridotite are exposed at the Earth’s surface in ophiolites, becoming vulnerable to the concurrent chemical alteration processes of serpentinization and carbonation. Serpentinization frequently results in the production of secondary magnetite that can record the direction of the Earth’s magnetic …
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From the Appalachians to the Alps: Constraints on the Timing, Duration, and Conditions of Metamorphism at Convergent Margins
… is applied to eclogite breccias from the Monviso ophiolite to quantify the periodicity of transient deformation and metamorphism at eclogite facies P-T conditions. The maximum timescale for repeated fracturing is constrained to ~1 Myr., likely caused by cyclic variations in fluid pressure and …
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Formation of mineralogical zonations in ophiolites through reactive porous flow : a modeling study
In the mantle section of many ophiolite sequences, dunite dikes are present. Around dunite dikes at the Josephine and Trinity ophiolite, a sequence of lithologies consisting of plagioclase lherzolite, lherzolite, and harzburgite is present. This sequence of rocks has been interpreted to be the …
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The origin and tectonic significance of the mafic-ultramafic association in the central Virginia Blue Ridge post-Grenville cover sequence
… are part of a Late Proterozoic to Ordovician ophiolite-bearing sequence or part of an intrusive-extrusive sequence related to the Late Proterozoic Iapetan rifting has major implications for Appalachian tectonic models. Current models consider most of the Blue Ridge cover sequence to be …
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Magma genesis in the northern Lau Basin, S.W. Pacific
… Junction. The 1982 'Kallisto' cruise dredged two ophiolite sections, one containing boninitic, and the other tholeiitic, lavas, from the inner wall of the northern Tonga trench. The magma genesis of these lava suites is related to the structural and geochemical controls imposed during the tectonic …
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