Hornblende occurs in some andesitic and basaltic rocks of calc-alkaline affini1y, where it is commonly associated with olivine. The texture, eruption history, and composition are interpreted to indicate that hornblende commonly forms as a product of reaction between olivine and basaltic and andesitic liquids. The natural hornblendes probably formed within the crust at temperatures between 960o ...

The prograde metamorphism of eclogites is typically obscured by chemical equilibration at peak conditions and by partial requilibration during retrograde metamorphism. Eclogites from the Eastern Blue Ridge of North Carolina retain evidence of their prograde path in the form of inclusions preserved in garnet. These eclogites, from the vicinity of Bakersville, North Carolina, USA are primarily co...

[1] Glacial sedimentary sequences in the north central United States record multiple advances of the Laurentide Ice Sheet (LIS) since 2 Ma. Although the tills found in these sequences were deposited by southward flowing glacial lobes, little information is available on the geometry of flow lines in the interior of the LIS during any one glaciation, and the provenance of glacial deposits older t...

The Kap Edvard Holm Layered Series forms part of the East Greenland Tertiary Province, and was emplaced at shallow crustal level (at depths corresponding to a pressure of 1-2 kbar) during continental break-up. It consists of two suites: a gabbro suite comprising olivine and oxide gabbros, leucocratic olivine gabbros and anorthosites, and a suite of wehrlites that formed from the intrusion of th...

The AI-in-hornblende barometer potentially offers a basis for estimating crystallization pressure for granitic batholiths. However, owing to the simplicity of its formulation, misuse of the barometer can occur. Many granitic intrusions are emplaced at conditions inconsistent with those of the existing experimental calibrations, including f02 < NNO and/or variable to high temperature. The barome...

Five calc-alkaline plutons; Um Tagher, Abu Zawil, Um Gidri, Um Anab and El Ghuzah, in the northern Eastern Desert of Egypt were subjected to petrographic and mineralogical investigations. They are composed of varying proportions of quartz + plagioclase +potash feldspar+ biotite + hornblende± epidote ± calcite + titanite +magnetite + apatite and zircon. Electron microprobe analyses of coexisting...