A Monte Carlo algorithm to simulate the isothermal recrystallization process of snow is presented. The snow metamorphism is approximated by two mass redistribution processes: surface diffusion and sublimation-deposition. The algorithm is justified and its parametrization is determined. The simulation results are compared to experimental data, in particular, the temporal evolution of the specifi...

Introduction: In this work, we report on the results of a combined scanning electron microscopy and micro-Raman spectroscopy investigation of stishovite and coesite in shocked Hospital Hill quartzite from the Vredefort impact structure of South Africa. Sanples have investigated using optical microscopy and under the scanning electron microscope, using energy dispersive x-ray spectrometry (EDS),...

This paper argues that the presence of external control of fluid composition during metamorphism of iron-formation should be indicated by the occurrence of high-grade rocks which either lack the bufering assemblages such as olivine-magnetite-quartz or by the presence of such assemblages in which the silicates show a very restricted range in composition. A review of high-grade iron-formations fr...

Where plates converge, one-sided subduction generates two contrasting thermal environments in the subduction zone (low dT/dP) and in the arc and subduction zone backarc or orogenic hinterland (high dT/dP). This duality of thermal regimes is the hallmark of modern plate tectonics, which is imprinted in the ancient rock record as penecontemporaneous metamorphic belts of two contrasting types, one...

Microdiamonds from the Akluilâk minette dykes (Nunavut, Canada) are similar to diamonds formed in subducted metamorphic rocks. High concentrations of unaggregated nitrogen and positive delta(15)N suggest that the microdiamonds formed within rocks subducted to ultrahigh pressures before being sampled by the minette magma 1.8 billion years ago. This ultrahigh pressure metamorphism in North Americ...