TY - JOUR
T1 - Post-rift magmatism and hydrothermal activity in the central offshore Otway Basin and implications for igneous plumbing systems
AU - Niyazi, Yakufu
AU - Warne, Mark
AU - Ierodiaconou, Daniel
N1 - Funding Information:
The authors thank Geoscience Australia and the Geological Survey of Victoria, Australia, for providing the datasets used in this study. The authors thank Schlumberger and DownUnder Geosolutions (DUG Insight) for granting academic licenses of their respective seismic interpretation and visualization software packages to Deakin University, Australia. We also would like to thank the three reviewers (Alan Bischoff, David Jolley and one anonymous reviewer) and journal editor Michele Rebesco for their review and constructive comments that helped improve this manuscript. YN is supported by a Higher Degree Research Scholarship from the Deakin University and the Victorian Department of Environment, Land, Water and Planning as part of the Victorian Coastal Monitoring Program. YN would like to thank Halinur and Ilterisch for their enourmous support during the preparation of this contribution.
Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/8
Y1 - 2021/8
N2 - Spatially and volumetrically extensive igneous rocks are exposed onshore in southeastern Australia and provide important information about the Cenozoic evolution of the region. However, the morphology and distribution of igneous rocks are still not well constrained in the ~70 km wide continental shelf of the central Otway Basin. Within this region, we present seismo-geomorphological characteristics of 30 volcanoes and 27 hydrothermal vents, as well as several lava flows and magmatic sills, based on 2D and 3D seismic reflection data. Hydrothermal vents formed mainly during the mid-Eocene, while igneous complexes developed between the mid-Eocene to late Miocene, both post-dating continental break-up in the basin. The distribution and morphology of igneous rocks and hydrothermal vents is influenced by rift-related faults, as most of these features are linked to the underlying faults by near-vertical zones of disruption and are elongated in an NW-SE direction that parallels the primary fault trend. Magma for volcanoes and heat sources for hydrothermal vents within the study area are likely supplied by deep-sourced dykes, as magmatic sills only have a scattered distribution in this region. This implies a dyke-dominated plumbing system for magmatism in the Otway Basin. In comparison, the nearby Bight Basin, which has a thin basement but a relatively thick sedimentary sequence, displays magma propogation more prone to forming igneous sills. There are significant lithological and tectonic similarities between the Otway and Bight basins; thus, we propose that a relatively thin sedimentary sequence over a thick basement in the Otway Basin produced sufficient magma pressure for a predominantly dyke-dictated igneous plumbing system. This work highlights the critical role of basin structures, such as the thickness of basement and overlying strata, in the control of igneous plumbing styles and the distribution of post-rift igneous complexes along magma-poor continental margins. Our work, therefore, aids the estimation of different magmatic components within the sedimentary basins and facilitates the understanding of their diverse impacts on the exploration of frontier basins. This result also provides some constraints on the prediction of possible future eruption centres within active volcanic fields.
AB - Spatially and volumetrically extensive igneous rocks are exposed onshore in southeastern Australia and provide important information about the Cenozoic evolution of the region. However, the morphology and distribution of igneous rocks are still not well constrained in the ~70 km wide continental shelf of the central Otway Basin. Within this region, we present seismo-geomorphological characteristics of 30 volcanoes and 27 hydrothermal vents, as well as several lava flows and magmatic sills, based on 2D and 3D seismic reflection data. Hydrothermal vents formed mainly during the mid-Eocene, while igneous complexes developed between the mid-Eocene to late Miocene, both post-dating continental break-up in the basin. The distribution and morphology of igneous rocks and hydrothermal vents is influenced by rift-related faults, as most of these features are linked to the underlying faults by near-vertical zones of disruption and are elongated in an NW-SE direction that parallels the primary fault trend. Magma for volcanoes and heat sources for hydrothermal vents within the study area are likely supplied by deep-sourced dykes, as magmatic sills only have a scattered distribution in this region. This implies a dyke-dominated plumbing system for magmatism in the Otway Basin. In comparison, the nearby Bight Basin, which has a thin basement but a relatively thick sedimentary sequence, displays magma propogation more prone to forming igneous sills. There are significant lithological and tectonic similarities between the Otway and Bight basins; thus, we propose that a relatively thin sedimentary sequence over a thick basement in the Otway Basin produced sufficient magma pressure for a predominantly dyke-dictated igneous plumbing system. This work highlights the critical role of basin structures, such as the thickness of basement and overlying strata, in the control of igneous plumbing styles and the distribution of post-rift igneous complexes along magma-poor continental margins. Our work, therefore, aids the estimation of different magmatic components within the sedimentary basins and facilitates the understanding of their diverse impacts on the exploration of frontier basins. This result also provides some constraints on the prediction of possible future eruption centres within active volcanic fields.
KW - Basin structures
KW - Buried volcanoes
KW - Hydrothermal vents
KW - Igneous plumbing system
KW - Otway Basin
UR - http://www.scopus.com/inward/record.url?scp=85108433013&partnerID=8YFLogxK
U2 - 10.1016/j.margeo.2021.106538
DO - 10.1016/j.margeo.2021.106538
M3 - Article
AN - SCOPUS:85108433013
SN - 0025-3227
VL - 438
JO - Marine Geology
JF - Marine Geology
M1 - 106538
ER -