This paper is the fourth in a series relating the lattice vibrational properties to the thermodynamic properties of minerals. The temperature dependence of the harmonic lattice heat capacity is calculated from a model which uses only elastic, crystallographic, and spectroscopic data for the following minerals: calcite, zircon, forsterite, grossular, pyrope, almandine, spessartine, andradite, ky...

Integrated metamorphic and geochronological data place new constraints on the metamorphic evolution of a Neoproterozoic orogen in east Antarctica. Granulite-facies rocks from a 150 km stretch of the Kemp Land coast reflect peak conditions involving T 870^9908C at P 7 4^10 kbar, with pressure increasing westward towards an Archaean craton. Electron microprobe-derived (ThþU)^Pb monazite ages from...

The relations of fibrolite-biotite are discussed by presenting data from the Ardara aureole, NW Ireland. Biotite-fibrolite intergrowths are developed in all three aureole zones including: the outer kyanite-bearing andalusite zone, the middle kyanite-free andalusite zone and the inner prismatic sillimanite zone. A strain-assisted mechanism is proposed for the fibrolitisation of biotite in the Ar...

Mullite is an aluminosilicate of the composition Al2(Al212xSi222x)O102x with x generally ranging between 0.2 and 0.5. XRD and 29Si and 27Al nuclear magnetic resonance (NMR) have been used to investigate the structure of various mullite compositions (x 5 0.26, 0.36, 0.42, and 0.69) as well as sillimanite (x 5 0) and g-Al2O3 (x 5 1). 27Al magic angle spinning (MAS) NMR of the central and satellit...

Mineral compositions and reaction textures found in migmatitic gneisses from near Gilsum, New Hampshire, constrain both peak metamorphic pressure (P) and temperature (T) conditions and the PT path. Large K-feldspar porphyroblasts indicate isobaric heating of the samples at P < 4 kb (Spear et al. 1999), and relict cordierite + garnet assemblages record the occurrence of biotite vapor-absent melt...

Field, structural, and metamorphic petrology investigations of Mabja gneiss dome, southern Tibet, suggest that contractional, extensional, and diapiric processes contributed to the structural evolution and formation of the domal geometry. The dome is cored by migmatites overlain by sillimanite-zone metasedimentary rocks and orthogneiss; metamorphic grade diminishes upsection and is defined by a...

A thick succession of sedimentary rocks belonging to Tipam Group is well exposed all along the road cut sections near Buhchang village, Kolasib district, Mizoram. The heavy mineral suite of the Tipam sediments depicts a cosmopolitan nature. It comprises dominantly of non-opaque variety that includes zircon, tourmaline, rutile, staurolite, kyanite, sillimanite, apatite, epidote, garnet and hornb...