Mineral Environments
- Marble Xenoliths -

     "The white to pale green marble xenoliths (inclusions) which are periodically exposed during quarrying operations were dragged from the Precambrian basement complex by the rising magma, and underwent a relatively low degree of thermal metamorphism during transport. They are probably Grenvillian in age, because no later regional metamorphism took place in the region, prior to the Cretaceous intrusion of MSH".*

     "The marble xenoliths average 1-2 meters across, are white to pale green in color and are an obvious feature of the quarry walls where they stand out against the darker nepheline syenite. Some of these xenoliths show dark, distinct metasomatized rims or contact zones, consisting mostly of anhedral to euhedral crystals of vesuvianite, and rarely grossular and miserite".*

Marble xenolith
© Quintin Wight

     "The composition of the marbles differs from block to block, from almost pure calcite to those rich in sodic and calcic silicates and rare element minerals".*

     "The very interesting suite of minerals found in this environment, occur embedded in the marble, or more importantly as free growing crystals in randomly distributed spherical or oblong-shaped cavities in the marble. The cavities average 5 - 15 cm in diameter with some oblong-shaped cavities attaining 35 cm in length. Cavities are characteristically lined with inter grown, fibrous pectolite with well formed pectolite crystals growing into the core. Most other minerals found in these cavities have grown on pectolite".*

* From Mineralogical Record Vol 21, Horváth L. and Gault R.A.