Welcome to the website of John S. Mason MPhil, Machynlleth, Wales, UK

- research - interpretation - photography - publication - conservation - site assessment -

the product of 25 years experience in the Earth sciences and information/communication technology


I graduated in geology in 1985 at Aberystwyth. Through a long-standing interest in mineralogy and ore deposits I have focussed much of my geological research towards the interplay between mineral deposits and regional geological processes through time.

I was trained in mineral exploration by the British Geological Survey and then spent time in the commercial world on a gold exploration project in the Scottish Dalradian, where a significant swarm of narrow but high-grade auriferous veins was assessed. More recently I have worked in the Dolgellau Gold-belt, North Wales, where geological controls on high-grade gold-shoots are the key to success.

Much of my academic research through the 1980s and 90s was into the metalliferous mineralisation of the old lead-mining district of Central Wales, which is now recognised as a complex orefield in which multiple phases of mineralisation involving not only Pb and Zn but also more exotic elements like Co, Ni and Sb have occurred. Please click here for details. By the mid-1990s I had started to explore all over Wales in conjunction with the Minescan project (please see the Conservation section for details). Such research involves fieldwork followed up by laboratory investigations and the information generated is not only of academic importance; it has applications in many issues surrounding metal-mining, from economic through to environmental.

One of my key research interests is in the relationship between mineralisation and deformation. This led in 1997 to my discovery that the gold-bearing veins of the Dolgellau area pre-date the regional Acadian deformation - they were for many years believed to post-date it. Click here for an account of the geology of the Dolgellau Gold-belt. Click here to learn about another project I am working on - Alpine fissure-veins in North Wales' slate-belt. More recently, I was a key writer of Volume 2 of A Mineralogy of Wales, produced in web format, available here. For a substantial bibliography of Welsh geology and mineralisation please click here. For a list of my scientific publications please click here.

Geology and metallogenesis in Wales
scientific interpretation services
conserving our geological heritage
Graphics & web design
the first UK occurrence of the Ni-Sb sulphide Tucekite from Central Wales
Electron microscope image of unusually crystallised pyrite from North Wales The lead chlorophosphate pyromorphite Banded tuff-turbidite with Alpine fissure-veins, Cwmorthin, N Wales
Tucekite - 1st UK occurrence
Reticulated pyrite - N Wales
Pyromorphite - Mid Wales
Cwmorthin Quarry, N Wales