The tin zone: sediment-hosted hydrothermal tin mineralization at Rooiberg, South Africa

Abstract

The Rooiberg tin field, also known as the

A novel approach to lead isotope provenance studies of tin and bronze: applications to South African, Botswanan and Romanian artifacts

“…There are at least eleven small copper deposits within the Rooiberg Fragment that are genetically related to the LGS (Rozendaal et al, 1995;Henry and Wilson, 2006). We measured Pb isotopic ratios on five pieces of smelted copper from surface scatters in the Rooiberg valley, and on three pieces of arsenical copper ore from one of these copper deposits.…”

“…1850 AD (Recknagel, 1908;Baumann, 1919;Chirikure et al, 2007Chirikure et al, , 2010. The ores are composed of pockets, stratiform lodes, and near-vertical fracture fillings of cassiterite, tourmaline, and carbonates (siderite or ankerite), with abundant pyrite and other sulfides (mostly chalcopyrite, with rare galena and scheelite) (Leube and Stumpfl, 1963;Rozendaal et al, 1995;Crocker et al, 2001;Labuschagne, 2004). The tin deposits are emplaced within the Rooiberg fragment, a remnant of Transvaal Supergroup sediments and Rooiberg Group rhyolites that was floated up by the emplacement of the magmas of the Bushveld Magmatic Province (BMP) between 2060 and 2050 million years ago (Ma).…”

“…The tuyeres are composed of clays naturally tempered with arkose rock fragments (Chirikure et al, 2010). Arkose and shales of the Transvaal form the floor of the Rooiberg valley and are older than the tin ore deposits within them (Rozendaal et al, 1995). Since these sedimentary rocks formed through deposition of materials eroded from still older rocks, the clays derived from arkose and shales in the furnace lining and tuyeres are expected to have different Pb isotopic ratios than the tin ore.…”

The technology of tin smelting in the Rooiberg Valley, Limpopo Province, South Africa, ca. 1650–1850 CE

“…The tin mineralization occurs within metasomatically altered sediments (probably originally quartzites) in the Rooiberg Fragment, a roughly triangular remnant of older Transvaal Supergroup and Rooiberg Group rocks that was floated up by the emplacement of the BMP. The Rooiberg Fragment is surrounded and underlain by highly evolved BMP granites, one of which is thought to have been the source of the tin-bearing fluids (Rozendaal et al, 1995;Schweitzer et al, 1995;Crocker et al, 2001;Labuschagne, 2004).…”

“…The tin ores that were exploited by the ancient miners consist of fracture fillings, together with cylindrical pipes and strata-bound pockets that have penetrated into and replaced the host rock. Beyond the ore bodies the host rock was transformed into an arkose by infusion with sodium-and potassium-bearing fluids (Rozendaal et al, 1995;Labuschagne, 2004). The ore mineral assemblage is tourmaline, cassiterite, carbonates (ankerite and magnesian siderite), and sulphides (predominantly pyrite, with rare pyrrhotite, chalcopyrite, bismuthinite, sphalerite and galena) (Stumpfl, 1960;Stumpfl, 1963a, 1963b;Crocker et al, 2001).…”