The Open University's repository of research publications and other research outputs Late Cretaceous (81Ma) high-temperature metamorphism in the southeastern Lhasa terrane: implication for the Neo-Tethys ocean ridge subduction. (2013). Late Cretaceous (81Ma) high-temperature metamorphism in the southeastern Lhasa terrane: implication for the Neo-Tethys ocean ridge subduction. Tectonophysics, 60...

The crystalline basement of New Zealand shows a chi-shaped combination of the straight Alpine Fault and a curved late Paleozoic continental margin, so that the plutonic basement of northern Fiordland converges toward the plane of the Alpine Fault. On the ground along Milford Sound the petrography suggests (1) a gradual change from amphibolite and granulite fades in the west to igneous fabrics d...

Charnockitic rocks form extensive orthogneiss plutons in many granulite terranes and are less commonly found in unmetamorphosed plutons, which have formed in various tectonic regimes. Geochemically, clearly igneous charnockites cover nearly the whole range of granite chemistry, from magnesian to ferroan and from calcic to alkalic. Pyroxenes from unmetamorphosed charnockitic rocks have compositi...

Rb–Sr and U–Pb isotopic data for granulite facies rocks, forming textural relics with respect to eclogite facies metamorphism in the Western Gneiss Region (WGR) of Norway, highlight the importance of textures and mineral reaction kinetics for the interpretation of geochronological data. Studied rocks from Bårdsholmen, southern WGR, were subjected to granulite facies metamorphism at 955 ± 3 Ma (...

Detailed electron-microprobe line profiles and small-area compositional maps of zoned garnets in a sample of high-pressure–high-temperature granulite show features inconsistent with commonly applied diffusion models. Larger grains of an early garnet generation have their highest Ca contents in domains away from the rim or inclusions but show a sharp fall in Ca balanced by increased Mg and Fe (a...

Metamorphism associated with orogenesis provides a mineral record that may be inverted to yield ambient apparent thermal gradients. On modern Earth, tectonic settings with lower thermal gradients are characteristic of subduction zones whereas those with higher thermal gradients are characteristic of backarcs and orogenic hinterlands. The duality of thermal environments reflects the asymmetry of...

Thermodynamic calculations for selected silicate-oxide-fluorite assemblages indicate that several commonly occurring fluorite-bearing assemblages are restricted to relatively narrow fo,-fF> fields at constant P-T. The presence of fayalite-ferrohedenbergite-fluorite-quartz *magnetite and ferrosalite-fluorite-quartz-magnetite assemblages in orthogneisses from Au Sable Forks, Wanakena and Lake Ple...