Only about 20 percent of the world’s identified tin resources occur as primary hydrothermal hard-rock veins, or lodes. These lodes contain predominantly high-temperature minerals and almost invariably occur in close association with silicic, peraluminous granites.

Because of the higher specific gravity of tin dioxide, about 80% of mined tin is from secondary deposits found downstream from the primary lodes. Tin is often recovered from granules washed downstream in the past and deposited in valleys or the sea.

Analyses of frequency distributions of tonnage, contained metal, tin grades and the relationships between these variables show that the deposits fall into four well-defined domains that have definite geological characteristics.

‘The Tin Lodes’ sequence stretches the catchment to the ruined tin mines on the nearby Cornish coast. It centres on the Graeco-French character Pytheas of Massalia, the first trader to come to Britain and annex the mines for the Roman Empire.

In the placer deposits, cassiterite grains are freed from the tin lodes by weathering processes and transported downslope into streams, followed by deposition when there was a reduction in the velocity of water flow. Over 90% of tin produced in Malaysia was …

primary tin deposits can be classified into a few types: vein-stock, pegmatite, skarn, carbonate replacement, porphyry and epithermal. The tin deposits in the Central Andes are largely concentrated in Bolivia. The geologic-tectonic framework of Bolivia can be divided into six physiographic provinces: Precambrian Shield, the Chaco-Beni Plains, the

Tin ore (cassiterite) occurring in veins, as distinguished from stream tin or placer tin. Compare with: stream tin

Multiple tin-bismuth bearing veins in weathered granite worked in small pits, shafts and tunnels. Dredging and sluicing operation 1871 to 1920 and intermittently to 1977. Located in Anderson parish, near Elsmore Hill approximately 1.5kms South-East of …

tin minerals been formed in situ except where the mineralization is genetically related to granite, or to the granite family rocks-mag- matic quartz veins, aplites, pegmatites, rhyolites and quartz porphyries or ‘elvans’ as they are known in Cornwall. Tin lodes may be mined some distance from the granite origin, as in the

To the west there are comparatively small tin lodes in the granite, and the "Copper Firing Line" occurs in the Older Metamorphic... This paper is based on studies made intermittently from 1937 to 1950.