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Structural controls on the location, geometry and longevity of an intraplate volcanic system: the Tuatara Volcanic Field, Great South Basin, New Zealand

Phillips, Thomas B.; Magee, Craig

Structural controls on the location, geometry and longevity of an intraplate volcanic system: the Tuatara Volcanic Field, Great South Basin, New Zealand Thumbnail


Authors

Thomas B. Phillips

Craig Magee



Abstract

Intraplate volcanism is widely distributed across the continents, but the controls on the 3D geometry and longevity of individual volcanic systems remain poorly understood. Geophysical data provide insights into magma plumbing systems, but, as a result of the relatively low resolution of these techniques, it is difficult to evaluate how magma transits highly heterogeneous continental interiors. We use borehole-constrained 2D seismic reflection data to characterize the 3D geometry of the Tuatara Volcanic Field located offshore New Zealand's South Island and investigate its relationship with the pre-existing structure. This c. 270 km2 field is dominated by a dome-shaped lava edifice, surrounded and overlain by c. 69 volcanoes and >70 sills emplaced over 40 myr from the Late Cretaceous to Early Eocene (c. 85–45 Ma). The Tuatara Volcanic Field is located above a basement terrane boundary represented by the Livingstone Fault; the recently active Auckland Volcanic Field is similarly located along-strike on North Island. We suggest that the Livingstone Fault controlled the location of the Tuatara Volcanic Field by producing relief at the base of the lithosphere, thereby focussing lithospheric detachment over c. 40 myr, and provided a pathway that facilitated the ascent of magma. We highlight how observations from ancient intraplate volcanic systems may inform our understanding of active intraplate volcanic systems, including the Auckland Volcanic Field.

Citation

Phillips, T. B., & Magee, C. (2020). Structural controls on the location, geometry and longevity of an intraplate volcanic system: the Tuatara Volcanic Field, Great South Basin, New Zealand. Journal of the Geological Society, 177(5), 1039-1056. https://doi.org/10.1144/jgs2020-050

Journal Article Type Article
Acceptance Date Jun 2, 2020
Online Publication Date Jul 6, 2020
Publication Date 2020-09
Deposit Date Oct 8, 2020
Publicly Available Date Jul 6, 2021
Journal Journal of the Geological Society
Print ISSN 0016-7649
Electronic ISSN 2041-479X
Publisher The Geological Society
Peer Reviewed Peer Reviewed
Volume 177
Issue 5
Pages 1039-1056
DOI https://doi.org/10.1144/jgs2020-050

Files

Accepted Journal Article (50.1 Mb)
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Copyright Statement
Phillips, Thomas B. & Magee, Craig (2020). Structural controls on the location, geometry and longevity of an intraplate volcanic system: the Tuatara Volcanic Field, Great South Basin, New Zealand. Journal of the Geological Society 177(5): 1039-1056. https://doi.org/10.1144/jgs2020-050 © Geological Society of London 2020.





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