
TY  - JOUR
A1  - Webster, S.S. 
T1  - A magnetic signature for tin deposits in south-east Australia
JF  - Exploration Geophysics
JO  - Explor. Geophys.
Y1  - 1984
VL  - 15
IS  - 1
SP  - 15
EP  - 31
KW  - 
UR  - https://doi.org/10.1071/EG984015 
N2  - The major hardrock tin deposits in south-east Australia have a characteristic magnetic signature in the vicinity of each deposit. This magnetic signature is due to the high temperatures of intrusion, being close to the Curie point of magnetite, imposing a remanent effect within the metamorphic aureole. The tin deposits are intimately related to the ilmenite series granitoids of lshihara (1978) which have been linked with the S-type granitoids of Chappell and White (1974). These granites are usually non-magnetic and circumscribed by magnetic aureoles in the country rock. These magnetic parameters can be explained by the temperature - oxygen fugacity characteristics of the parent melt. The non-tin-mineralized granitoid suite, labelled magnetite series by lshihara and I-type by Chappell and White, are moderately to strongly magnetic in south-east Australia. Non-magnetic I-type granitoids are common elsewhere, and can be caused by the replacement of Ti-magnetite by secondary sphene. The I-type granitoids (magnetite + sphene series) have a Cu - Mo - W mineral association. The relationship of tin mineralization to the S-type granitoids is that the deposits are found peripheral to the granitoids, in close association with their late and fine grained derivatives. The S-type granitoids may themselves be quite barren (Strong 1981). The mineralized late phase intrusions of north-west Tasmania exhibit a similar magnetic aureole to that surrounding the granitoids, as evidenced near the carbonate-replacement deposits at Mt Lindsay, Cleveland and Severn at Zeehan. Examples are given from north-west Tasmania to illustrate the signature of the Renison-Bell, Cleveland, Mt Lindsay and Severn deposits. Regional and local geophysical data from central New South Wales are presented to further illustrate the model for granites and mineralization at Ardlethan, Kikoira and Tallebung. 
ER  -

