The Aroche wollastonite deposits are found in the western edge of the Aracena Metamorphic Belt, a high-temperature/low-pressure metamorphic band located in south-west Spain.
The deposit, which is west of Seville and close to the border with Portugal, hosts five types of wollastonite.
Field work included geological mapping at a scale of 1:5000 to identify wollastonite occurrences and the collecting of hundreds of samples. Some samples are drill cores taken from outcrops across skarn-marble contacts.
Type I
This type of nearly pure wollastonite skarn was discovered in the 1980s as result of an exploration venture. In terms of economic recovery, it is the most promising deposit of the region. The mineralisation consists of massive, multiple and strike-parallel layers of wollastonite between marble and numerous near-vertical quartz dykes, and locally granitic pegmatoids, that crop out almost continuously over a distance of 4km following the trend of regional structures (NE-SW).
These...