Stratiform and stratabound tungsten mineralisation in the Broken Hill Block, N.S.W.
Titel:
Stratiform and stratabound tungsten mineralisation in the Broken Hill Block, N.S.W.
Auteur:
Barnes, Robert G.
Verschenen in:
Australian journal of earth sciences
Paginering:
Jaargang 30 (1983) nr. 1-2 pagina's 225-239
Jaar:
1983-07
Inhoud:
The Early-Middle Proterozoic Broken Hill Block contains three types of W occurrences, which show close stratigraphic control. All three types occur within a relatively narrow stratigraphic interval (the 'Mine Sequence' Suite of Stevens et al., 1980) comprising a highly variable group of metamorphosed silicic and mafic volcanics, clastic sediments, and exhalative and chemical sediments containing base metals. The first type includes occurrences of W and base metals in bedded calc-silicate rocks. In the second type, W occurs in layered to non-layered calcsilicate rocks associated with amphibolite; these are intimately associated in a narrow stratigraphic interval containing abundant, small, Broken Hill type deposits. The third type comprises stratabound, W-bearing pegmatites, which have been remobilised from quartz-feldspar-biotite gneiss and bedded quartz-tourmaline rocks. Tungsten has been mined only from the third type and only in small quantities. The three types of tungsten deposits show a close spatial relationship with stratiform and stratabound Pb-Zn mineralisation, including the Broken Hill type. The Pb-Zn and W deposits are inferred to be genetically related.
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