University of Tasmania
Browse

File(s) under permanent embargo

The geochronology of Tasmanian tin deposits using LA-ICP-MS U-Pb cassiterite dating

journal contribution
posted on 2023-05-20, 22:07 authored by Denholm, JL, Stepanov, AS, Sebastien MeffreSebastien Meffre, Bottrill, RS, Thompson, JM

The island state of Tasmania is the most important tin producer in Australia. The spatial and genetic relationship between Tasmanian tin deposits and Devonian-Carboniferous granites, which intruded throughout the Tabberabberan orogeny, has long been understood. However, little geochronological data is available to link mineralization to nearby intrusions. In this study, we investigate the connection between 19 Tasmanian tin deposits and their potential source granites, using U-Pb cassiterite dating by laser ablation-inductively coupled plasma-mass spectrometry. Archean pegmatitic cassiterite was also characterized and used for the calibration of U-Pb ratios.

Tin mineralization in Tasmania occurred between 391 ± 6.3 and 359 ± 7.8 Ma, which is coincident with most postorogenic granites of the Tabberabberan orogeny. In conjunction with the granite ages, cassiterite ages become younger from the east of the state to the west, and tin mineralization occurred over a protracted period spanning 32 m.y. Dating of several placer cassiterite samples produced unexpected results, such as the occurrence of 374 ± 4.7 Ma cassiterite on eastern King Island, an area known only to contain the 350 Ma Grassy granite, suggesting a distant provenance.

Tasmanian cassiterite rarely shows evidence of Pb loss; however, some analyses are characterized by elevated Th and U, likely caused by microinclusions such as monazite, which may have a detrimental effect on cassiterite U-Pb dating. This study demonstrates the utility of cassiterite dating for understanding the origin of tin deposits in complex terrains with protracted periods of tin mineralization.

Funding

Australian Research Council

Alkane Exploration NL

AngloGold Ashanti Australia Limited

CMOC Mining Services Pty Ltd T/A Northparkes Mines

Department of Economic Development, Jobs, Transport and Resources

Department of State Growth (Tas)

Emmerson Resources Limited

Evolution Mining

Geological Survey of New South Wales - Department of Industry

Geoscience Australia

Heron Resources Limited

New South Resources Limited

Rio Tinto Limited

Sandfire Resoures NL

History

Publication title

Economic Geology and The Bulletin of The Society of Economic Geologists

Pagination

1-22

ISSN

0361-0128

Department/School

School of Natural Sciences

Publisher

Economic Geology Publ Co

Place of publication

5808 South Rapp St, Ste 209, Littleton, USA, Co, 80120-1942

Rights statement

Copyright 2021 2021 Society of Economic Geologists, Inc.

Repository Status

  • Restricted

Socio-economic Objectives

Other mineral resources (excl. energy resources) not elsewhere classified; Expanding knowledge in the earth sciences

Usage metrics

    University Of Tasmania

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC