New high‐precision single grain U‐Pb zircon geochronology and whole rock Nd isotopic data provide insight into the magmatic tectonic development of Samail ophiolite. The analyzed rocks can be broadly divided two groups based on their structural position, dates, composition: an older group related to on‐axis magmatism a younger post‐ridge dikes, sills, stocks. On‐axis gabbros, tonalites trondhjemites yielded Th‐corrected 206 Pb/ 238 U dates from 96.441 ± 0.062 95.478 0.056 Ma. These combined...

New high‐precision U/Pb zircon geochronology from the Oman‐United Arab Emirates (U.A.E.) ophiolite provides insight into timing and duration of magmatism tectonic setting during formation lower crust. The new data come a well‐preserved exposed crustal section in center Wadi Tayin massif. Single grain fragment 206 Pb/ 238 U dates upper‐level gabbros, tonalites/trondhjemites gabbroic pegmatites, corrected for initial Th exclusion, range 112.55 ± 0.21 to 95.50 0.17 Ma, with most clustered...

We describe the Library of Experimental Phase Relations (LEPR), which is a new Web‐based database experiments pertaining to magmatic phase equilibria. The includes information from related natural or near‐natural silicate At present, more than 6,600 with liquids ranging in composition komatiite rhyolite performed at temperatures between 500 and 2500°C pressures up 27.5 GPa. Here we organization data metadata that are included as well structure implementation its Web interface. discuss number...

Integration of in situ and conventional ion microprobe U‐Th‐Pb zircon monazite geochronology with 40 Ar/ 39 Ar hornblende, biotite, muscovite thermochronology provides a temporal record metamorphism, partial melting, fluids, cooling exhumed midcrustal to lower crustal rocks. The Valhalla complex, southeastern British Columbia, is one series elongate gneiss domes within the Omineca belt Canadian Cordillera. We have performed age measurements on migmatitic gneisses from range structural levels...

Abstract Metamorphic core complexes are ubiquitous in collapsed orogens globally and play a primary role crustal exhumation. We investigate the metamorphic history of Ruby Mountains‐East Humboldt Range complex, Nevada, using petrochronology to understand how magmatism, metamorphism deformation interact modulate rheology, timing exhumation within Sevier orogenic belt. Field study, microstructural analysis, thermobarometry laser ablation split‐stream monazite, titanite allanite mylonitic...

In order to understand mass and heat transfer processes that operated during Himalayan orogenesis, we collected temperature, finite incremental strain, kinematic vorticity data through a 5 km thickness of Lesser Greater rocks in southern Bhutan. This transect crosses two major shear zones, the Main Central thrust (MCT) Shumar (ST). Raman spectroscopy on carbonaceous material garnet-biotite thermometry are integrated with deformation temperatures from quartz petrofabrics. These define...

Abstract Rare ultrahigh‐temperature–(near)ultrahigh‐pressure (UHT–near‐UHP) crustal xenoliths erupted at 11 Ma in the Pamir Mountains, southeastern Tajikistan, preserve a compositional and thermal record mantle depths of material subducted beneath largest collisional orogen on Earth. A combination oxygen‐isotope thermometry, major‐element thermobarometry pseudosection analysis reveals that, prior to eruption, partially equilibrated conditions ranging from 815 °C 19 kbar 1100 27 for eclogites...

Abstract Dehydration reactions within subducted oceanic crust are important for fluid‐mediated element transfer the subducting plate and potentially to mantle wedge. The effects of metamorphic fluid flow on recycling that occur during retrogression exhumation continental from depths poorly understood. We study two metabasite pods with fresh eclogite cores retrogressed amphibolite‐facies rims surrounding host gneiss Western Gneiss Region (WGR), Norway, better understand mobility mass crust....

The Sudete Mountains, NE Bohemian Massif (Czech Republic and Poland), preserve abundant eclogitic granulitic centimetre- to decimetre-scale boudins enveloped in a predominantly migmatitic matrix. Published geochronometry thermobarometry from the UHP UHT rocks broadly constrain crystallization initial stage 1 exhumation history for these units; however, timing of 2 metamorphism associated unroofing is less well constrained. New situ ion microprobe Th–Pb monazite results, together with...

The Sudete Mountains of northeastern Bohemian Massif were amalgamated during the closure Rheic ocean, culminating with Variscan orogenesis, and contain occurrences high-pressure granulite small relict ultrahigh-pressure eclogite formed subduction. We performed ⁴⁰Ar/³⁹Ar thermochronometry on primarily amphibolite-facies gneisses schists from two crustal blocks within Sudetes: Góry Sowie Orlica-Snieznik massifs. Hornblende mica plateau ages mountainous portion reflect...

Research Article| July 01, 2010 Time Scales of Metamorphism, Deformation, and Crustal Melting in a Continental Arc, North Cascades USA Stacia M. Gordon; Gordon † 1Department Earth Science, University California, Santa Barbara, California 93106, †E-mail: gordon@geol.ucsb.edu Search for other works by this author on: GSW Google Scholar Samuel A. Bowring; Bowring 2Department Planetary Sciences, Massachusetts Institute Technology, Cambridge, 02139, Donna L. Whitney; Whitney 3Department Geology...

The U-Pb age and Hf-isotope composition of detrital zircons from Jurassic to Upper Cretaceous sedimentary rocks adjacent the southern North Cascades–Coast Plutonic Complex continental magmatic arc document shifting provenance, tectonic evolution system, translation along margin. Systematic changes in detrital-zircon data provide insight that western margin America evolved from: marginal basins continent-fringing oceanic arcs (ca. 160–140 Ma); forearc mid-Cretaceous 120–90 Ma) Andean-type...

The North Cascades orogen (northwestern USA) provides an exceptional natural laboratory with which to evaluate potential temporal and kinematic links between processes operating at a wide range of crustal levels during collapse continental arc, particularly the compatibility strain upper lower crust. This magmatic arc reached thickness ≥55 km in mid-Cretaceous. Eocene regional transtension was marked by magmatism, migmatization, ductile flow, exhumation deep (8–12 kbar) rocks crystalline...

Abstract The metasupracrustal units within the north central Chelan block of North Cascades Range, Washington, are investigated to determine mechanisms and timescales supracrustal rock incorporation into deep crust continental magmatic arcs. Zircon U‐Pb Hf‐isotope analyses were used characterize protoliths metasedimentary metaigneous rocks from Skagit Gneiss Complex, Cascade River Schist, metavolcanic Napeequa Schist. Complex have (1) a wide range zircon dates Proterozoic latest Cretaceous...

The Swakane Gneiss, interpreted to represent sedimentary strata metamorphosed at 8–12 kbar, is the deepest exposed crustal levels within exhumed North Cascades continental magmatic arc, yet nature and age of its protolith mechanism by which it was transported deep-crustal remains unclear. Zircons from 11 paragneiss schist samples were analyzed for U-Pb Hf-isotope composition in order investigate tectonic history Gneiss deposition metamorphism arc. have crystallized situ during and/or...

In several places in the Himalaya, there are debates over location of and defining criteria for South Tibetan detachment (STD) system. Here, we attempt to resolve this debate central Bhutan by interpreting temperature, pressure, finite strain, shear-sense data from an 11-km-thick structural transect through Dang Chu region. Raman spectroscopy on carbonaceous material garnet-biotite thermometry define a gradual, structurally upward decrease 600–700 °C 400–500 °C, indicate pure shear-dominant...