| | The Cornubian Batholith (Site not responding. Last check: 2007-10-23) |
 | | Metasomatic tourmaline granites show every gradation from the above, with progressive elimination of micas and feldspars, to a quartz-tourmaline tourmalinite (some of which appear to be intrusive - products of extreme fractionation, such as the dyke at Roche Rock [SW992594] and the tourmalinite at Porth Ledden [SW354320] near Cape Cornwall). |
 | | Examples include rocks such as Luxullianite and Trevalganite. |
 | | Boron (and hence, tourmaline) has played a major part in the transport of metals during the high temperature phases of mineralisation (Charoy, 1982) and is a common constituent of main stage Sn lodes (Farmer, 1991) at depth (e.g., South Crofty Mine). |
| www.phdcsm.freeserve.co.uk /batholith.htm (8198 words) |