Cretaceous tungsten-tin mineralisation in the Tin Range, Stewart Island, New Zealand

• Main Authors: Lilley, Hamish C., Scott, James M., Schwartz, Josh J., Turnbull, Rose E., Tulloch, Andy J.
• Format: Dataset
• Language: unknown
• Published: Taylor & Francis 2021
• Subjects: Microbiology; FOS Biological sciences; 59999 Environmental Sciences not elsewhere classified; FOS Earth and related environmental sciences; 39999 Chemical Sciences not elsewhere classified; FOS Chemical sciences; Ecology; Developmental Biology; 60506 Virology; New Zealand; Antarc*; Antarctica
• Online Access: https://dx.doi.org/10.6084/m9.figshare.13554155; https://tandf.figshare.com/articles/dataset/Cretaceous_tungsten-tin_mineralisation_in_the_Tin_Range_Stewart_Island_New_Zealand/13554155

The discovery of placer tin in southern Stewart Island caused New Zealand's only known tin-rush. The source of at least some of the placer tin is greisenised granodiorite and metasedimentary rocks on the crest of the Tin Range. There are three mineralised lithologies: a sericite-quartz greisen, a quartz-topaz greisen, and a gahnite-schist greisen. However, very little cassiterite (SnO2) is observed and instead wolframite ((Fe,Mn)WO4) and gahnite (ZnAl2O4) are common. U-Pb dating of host early Paleozoic Pegasus Group metasediments indicate the area experienced metamorphism at ∼117 Ma (monazite), with granodiorite emplacement at 107.9 ± 2.2 Ma (zircon). U-Pb isotope and trace element analysis of xenotime in the mineralised zone reveals three distinct growth phases: one at 107.5 ± 1.8 Ma that overlaps with granodiorite emplacement, and then 94.2 ± 0.9 Ma and 91.6 ± 0.6 Ma. Although it is not clear precisely which growth phase correlates with mineralisation, it must have been a mid-Cretaceous event and we correlate it with the ∼108 Ma Tin Range Granodiorite. The window of mineralisation, ∼ 108-92 Ma, means that this event was likely associated with the initiation of thinning of the Zealandia lithosphere as a precursor to separation from Australia and Antarctica.