ORCID Profile
0000-0002-3170-3935
Current Organisation
University of Tasmania
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Geology | Geodynamics | Tectonics | Marine Geoscience | Palaeoclimatology | Geophysics | Geochemistry | Oceanography | Exploration Geochemistry | Physical Oceanography | Glaciology | Geology | Climate Change Processes | Microbial Genetics | Marine geoscience | Microbial genetics | Earth system sciences | Oceanography not elsewhere classified | Stratigraphy (incl. Biostratigraphy and Sequence Stratigraphy)
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Earth Sciences | Copper Ore Exploration | Effects of Climate Change and Variability on Antarctic and Sub-Antarctic Environments (excl. Social Impacts) | Effects of Climate Change and Variability on Australia (excl. Social Impacts) | Mineral Exploration not elsewhere classified | Expanding Knowledge in the Environmental Sciences | Precious (Noble) Metal Ore Exploration |
Related Links
Publications
A Multivariate Approach for Mapping Lithospheric Domain Boundaries in East Antarctica
Publisher: American Geophysical Union (AGU)
Date: 09-2019
DOI: 10.1029/2019GL083453
The Evolving Paleobathymetry of the Circum‐Antarctic Southern Ocean Since 34 Ma: A Key to Understanding Past Cryosphere‐Ocean Developments
Publisher: American Geophysical Union (AGU)
Date: 08-2020
DOI: 10.1029/2020GC009122
A push in the right direction: exploring the role of Zealandia collision in Eocene Pacific-Australia plate motion changes
Publisher: Authorea, Inc.
Date: 11-06-2023
Seismic stratigraphy of the Adare Trough area, Antarctica
Publisher: Elsevier BV
Date: 08-2006
Long-term interaction between mid-ocean ridges and mantle plumes
Publisher: Springer Science and Business Media LLC
Date: 25-05-2015
DOI: 10.1038/NGEO2437
Microcontinents
Publisher: Springer International Publishing
Date: 2020
Intraplate magmatism
Publisher: Springer Netherlands
Date: 2016
A tectonic model reconciling evidence for the collisions between India, Eurasia and intra-oceanic arcs of the central-eastern Tethys
Publisher: Elsevier BV
Date: 09-2015
How supercontinents and superoceans affect seafloor roughness
Publisher: Springer Science and Business Media LLC
Date: 12-2008
DOI: 10.1038/NATURE07573
Abstract: Seafloor roughness varies considerably across the world's ocean basins and is fundamental to controlling the circulation and mixing of heat in the ocean and dissipating eddy kinetic energy. Models derived from analyses of active mid-ocean ridges suggest that ocean floor roughness depends on seafloor spreading rates, with rougher basement forming below a half-spreading rate threshold of 30-35 mm yr(-1) (refs 4, 5), as well as on the local interaction of mid-ocean ridges with mantle plumes or cold-spots. Here we present a global analysis of marine gravity-derived roughness, sediment thickness, seafloor isochrons and palaeo-spreading rates of Cretaceous to Cenozoic ridge flanks. Our analysis reveals that, after eliminating effects related to spreading rate and sediment thickness, residual roughness anomalies of 5-20 mGal remain over large swaths of ocean floor. We found that the roughness as a function of palaeo-spreading directions and isochron orientations indicates that most of the observed excess roughness is not related to spreading obliquity, as this effect is restricted to relatively rare occurrences of very high obliquity angles (>45 degrees ). Cretaceous Atlantic ocean floor, formed over mantle previously overlain by the Pangaea supercontinent, displays anomalously low roughness away from mantle plumes and is independent of spreading rates. We attribute this observation to a sub-Pangaean supercontinental mantle temperature anomaly leading to slightly thicker than normal Late Jurassic and Cretaceous Atlantic crust, reduced brittle fracturing and smoother basement relief. In contrast, ocean crust formed above Pacific superswells, probably reflecting metasomatized lithosphere underlain by mantle at only slightly elevated temperatures, is not associated with basement roughness anomalies. These results highlight a fundamental difference in the nature of large-scale mantle upwellings below supercontinents and superoceans, and their impact on oceanic crustal accretion.
Revisiting the Australian‐Antarctic Ocean‐Continent Transition Zone Using Petrological and Geophysical Characterization of Exhumed Subcontinental Mantle
Publisher: American Geophysical Union (AGU)
Date: 07-2020
DOI: 10.1029/2020GC009040
Abstract: The final lithospheric breakup of the Australian‐Antarctic rift system remains controversial due to sparse geological constraints on the nature of the basement along the ocean‐continent transition (OCT) zones. We present new interpretations of multichannel seismic reflection transects and new petrological data of dredged mantle rocks along the East Antarctic margin (Seamount B, offshore Terre Adélie). By combining both data sets, we show that a 50–100 km wide domain of cold and fertile subcontinental mantle was exhumed along the magma‐poor Antarctic margin. This study represents only the second locality, along with the Iberia‐Newfoundland margins, where the importance of exhumed mantle domains along OCTs can be clearly identified. The dredged peridotites preserve characteristics similar to mantle xenoliths found in syn‐ to post‐rift volcanism at the eastern end of the Australian margin (Victoria and Tasmania), indicating the exhumation of fertile subcontinental mantle during rifting between Australia and Antarctica. Seamount B represents the initial stages of exhumation of cold subcontinental lithosphere along an OCT during rifting. This thick mantle domain was likely affected by melt impregnation at high pressure (8 kbar), leading to the formation of plagioclase‐pyroxenites. The combination of continental rifted blocks, a wide domain of volcanic‐poor subcontinental mantle and (ultra‐) slow spreading is analogous to OCTs from the Jurassic Western Tethys and Iberia‐Newfoundland rifted margins. Additionally, evidence of melt stagnation at high pressure suggests that magmatism along the Australian‐Antarctic rifted margins was sufficient to form magnetic anomalies that can be used as isochrons despite their formation in lithosphere other than mature, steady‐state ocean crust.
Pangea Rifting Shaped the East Antarctic Landscape
Publisher: American Geophysical Union (AGU)
Date: 08-2020
DOI: 10.1029/2020TC006180
Acoustic Predictors of Active Fluid Expulsion From a Hydrothermal Vent Field, Offshore Taupō Volcanic Zone, New Zealand
Publisher: Frontiers Media SA
Date: 24-01-2022
DOI: 10.3389/FEART.2021.785396
Abstract: Understanding fluid expulsion is key to estimating gas exchange volumes between the seafloor, ocean, and atmosphere for locating key ecosystems and geohazard modelling. Locating active seafloor fluid expulsion typically requires acoustic backscatter data. Areas of very-high seafloor backscatter, or “hardgrounds,” are often used as first-pass indicators of potential fluid expulsion. However, varying and inconsistent spatial relationships between active fluid expulsion and hardgrounds means a direct link remains unclear. Here, we investigate the links between water-column acoustic flares to seafloor backscatter and bathymetric metrics generated from two calibrated multibeam echosounders. Our site, the Calypso hydrothermal vent field (HVF) in the Bay of Plenty, Aotearoa/New Zealand, has an extensive catalogue of vents and seeps in & m water depth. We demonstrate a method to quantitatively link active fluid expulsion (flares) with seafloor characteristics. This allows us to develop predictive spatial models of active fluid expulsion. We explore whether data from a low (30 kHz), high (200 kHz), or combined frequency model increases predictive accuracy of expulsion locations. This research investigates the role of hardgrounds or surrounding sediment cover on the accuracy of predictive models. Our models link active fluid expulsion to specific seafloor characteristics. A combined model using both the 30 and 200 kHz mosaics produced the best results (predictive accuracy: 0.75 Kappa: 0.65). This model performed better than the same model using in idual frequency mosaics as input. Model results reveal active fluid expulsion is not typically associated with the extensive, embedded hardgrounds of the Calypso HVF, with minimal fluid expulsion. Unconsolidated sediment around the perimeter of and between hardgrounds were more active fluid expulsion sites. Fluids exploit permeable pathways up to the seafloor, modifying and refashioning the seafloor. Once a conduit self-seals, fluid will migrate to a more permeable pathway, thus reducing a one-to-one link between activity and hardgrounds. Being able to remotely predict active and inactive regions of fluid expulsion will prove a useful tool in rapidly identifying seeps in legacy datasets, as well as textural metrics that will aid in locating nascent, senescent, or extinct seeps when a survey is underway.
Authigenic monazite and detrital zircon dating from the Proterozoic Rocky Cape Group, Tasmania: Links to the Belt-Purcell Supergroup, North America
Publisher: Elsevier BV
Date: 09-2014
Erosional and depositional processes on the submarine flanks of Ontong Java and Nukumanu atolls, western equatorial Pacific Ocean
Publisher: Elsevier BV
Date: 10-2017
Mantle plumes and their role in Earth processes
Publisher: Springer Science and Business Media LLC
Date: 25-05-2021
Displacement along the Red River Fault constrained by extension estimates and plate reconstructions
Publisher: American Geophysical Union (AGU)
Date: 10-2012
DOI: 10.1029/2012TC003174
Sea-level fluctuations driven by changes in global ocean basin volume following supercontinent break-up
Publisher: Elsevier BV
Date: 09-2020
Provenance of Upper Jurassic–Lower Cretaceous strata in the Mentelle Basin, southwestern Australia, reveals a trans-Gondwanan fluvial pathway
Publisher: Elsevier BV
Date: 05-2021
GlobSed: Updated Total Sediment Thickness in the World's Oceans
Publisher: American Geophysical Union (AGU)
Date: 04-2019
DOI: 10.1029/2018GC008115
Deepening of Southern Ocean gateway leads to abrupt onset of a deep-reaching meridional overturning circulation
Publisher: Authorea, Inc.
Date: 09-02-2023
DOI: 10.22541/ESSOAR.167590830.09227890/V1
Abstract: During the Eocene-Oligocene transition, the meridional overturning circulation underwent large changes, associated with the geological evolution of Southern Ocean gateways. These are crucial for the Cenozoic climate transition from Greenhouse to Icehouse, but their dynamics still remain elusive. We demonstrate, using an idealised eddying ocean model, that the opening of a gateway leads to an abrupt onset of a vigorous, deep-reaching, meridional overturning circulation. This meridional overturning circulation has a maximum transport for a shallow gateway, and decreases with further deepening of the gateway. This abrupt change in the meridional overturning circulation can be explained through the ability with which standing meanders – turbulent features located downstream of the gateway – can induce deep vertical heat transport at high latitudes where bottom waters are produced. Our results demonstrate the crucial role of turbulent processes, associated with tectonic evolution, in setting the strength of the global ocean’s deep-reaching meridional overturning circulation.
Full-fit reconstruction of the labrador sea and baffin bay
Publisher: Copernicus GmbH
Date: 26-11-2013
Abstract: Abstract. Reconstructing the opening of the Labrador Sea and Baffin Bay between Greenland and North America remains controversial. Recent seismic data suggest that magnetic lineations along the margins of the Labrador Sea, originally interpreted as seafloor spreading anomalies, may lie within the crust of the continent–ocean transition. These data also suggest a more seaward extent of continental crust within the Greenland margin near Davis Strait than assumed in previous full-fit reconstructions. Our study focuses on reconstructing the full-fit configuration of Greenland and North America using an approach that considers continental deformation in a quantitative manner. We use gravity inversion to map crustal thickness across the conjugate margins, and assimilate observations from available seismic profiles and potential field data to constrain the likely extent of different crustal types. We derive end-member continental margin restorations following alternative interpretations of published seismic profiles. The boundaries between continental and oceanic crust (COB) are restored to their pre-stretching locations along small circle motion paths across the region of Cretaceous extension. Restored COBs are fitted quantitatively to compute alternative total-fit reconstructions. A preferred full-fit model is chosen based on the strongest compatibility with geological and geophysical data. Our preferred model suggests that (i) the COB lies oceanward of magnetic lineations interpreted as magnetic anomaly 31 (70 Ma) in the Labrador Sea, (ii) all previously identified magnetic lineations landward of anomaly 27 reflect intrusions into continental crust and (iii) the Ungava fault zone in Davis Strait acted as a leaky transform fault during rifting. This robust plate reconstruction reduces gaps and overlaps in Davis Strait and suggests that there is no need for alternative models proposed for reconstructions of this area including additional plate boundaries in North America or Greenland. Our favoured model implies that break-up and formation of continent–ocean transition (COT) first started in the southern Labrador Sea and Davis Strait around 88 Ma and then propagated north and southwards up to the onset of real seafloor spreading at 63 Ma in the Labrador Sea. In Baffin Bay, continental stretching lasted longer and actual break-up and seafloor spreading started around 61 Ma (chron 26).
Tectonic, Oceanographic, and Climatic Controls on the Cretaceous-Cenozoic Sedimentary Record of the Australian-Antarctic Basin
Publisher: American Geophysical Union (AGU)
Date: 08-2019
DOI: 10.1029/2018JB016683
Full-fit, palinspastic reconstruction of the conjugate Australian-Antarctic margins
Publisher: American Geophysical Union (AGU)
Date: 12-2011
DOI: 10.1029/2011TC002912
Response to Comment on Major Australian-Antarctic Plate Reorganization at Hawaiian-Emperor Bend Time
Publisher: American Association for the Advancement of Science (AAAS)
Date: 25-07-2008
Abstract: Accurately locating boundaries between continental and oceanic crust is topical in view of locating offshore boundaries relevant to margin formation models, plate kinematics, and frontier resource exploration. Although we disagree with Tikku and Direen's interpretations, the associated controversies reflect an absence of agreed-upon geophysical criteria for distinguishing stretched continental from oceanic crust, and a lack of s les from nonvolcanic margins.
Revised tectonic evolution of the Eastern Indian Ocean
Publisher: American Geophysical Union (AGU)
Date: 06-2013
DOI: 10.1002/GGGE.20120
Antarctic sedimentary basins and their influence on ice sheet dynamics
Publisher: Wiley
Date: 16-06-2023
Geologic and kinematic constraints on Late Cretaceous to mid Eocene plate boundaries in the southwest Pacific
Publisher: Elsevier BV
Date: 2015
Antarctica's sedimentary basins and their influence on ice sheet dynamics
Publisher: Wiley
Date: 03-04-2023
Antarctica's subglacial sedimentary basins and their influence on ice-sheet change
Publisher: Wiley
Date: 24-03-2022
Modelling the Palaeozoic tectonic evolution of the Lachlan Orogen
Publisher: Informa UK Limited
Date: 11-11-2019
Shallow Seafloor Gas emissions Near Heard and McDonald Islands on the Kerguelen Plateau, Southern Indian Ocean
Publisher: American Geophysical Union (AGU)
Date: 03-2020
DOI: 10.1029/2019EA000695
Abstract: Bubble emission mechanisms from submerged large igneous provinces remains enigmatic. The Kerguelen Plateau, a large igneous province in the southern Indian Ocean, has a long sustained history of active volcanism and glacial/interglacial cycles of sedimentation, both of which may cause seafloor bubble production. We present the results of hydroacoustic flare observations around the underexplored volcanically active Heard Island and McDonald Islands on the Central Kerguelen Plateau. Flares were observed with a split‐beam echosounder and characterized using multifrequency decibel differencing. Deep‐tow camera footage, water properties, water column δ 3 He, subbottom profile, and sediment δ 13 C and δ 34 S data were analyzed to consider flare mechanisms. Excess δ 3 He near McDonald Islands seeps, indicating mantle‐derived input, suggests proximal hydrothermal activity McDonald Islands flares may thus indicate CO 2 , methane, and other minor gas bubbles associated with shallow diffuse hydrothermal venting. The Heard Island seep environment, with subbottom acoustic blanking in thick sediment, muted 3 He signal, and δ 13 C and δ 34 S fractionation factors, suggest that Heard Island seeps may either be methane gas (possibly both shallow biogenic methane and deeper‐sourced thermogenic methane related to geothermal heat from onshore volcanism) or a combination of methane and CO 2 , such as seen in sediment‐hosted geothermal systems. These data provide the first evidence of submarine gas escape on the Central Kerguelen Plateau and expand our understanding of seafloor processes and carbon cycling in the data‐poor southern Indian Ocean. Extensive sedimentation of the Kerguelen Plateau and additional zones of submarine volcanic activity mean additional seeps or vents may lie outside the small survey area proximal to the islands.
Timing and causes of the mid-Cretaceous global plate reorganization event
Publisher: Elsevier BV
Date: 03-2020
The sensitivity of the Eocene–Oligocene Southern Ocean to the strength and position of wind stress
Publisher: Copernicus GmbH
Date: 21-12-2022
Abstract: Abstract. The early Cenozoic opening of the Tasmanian Gateway (TG) and Drake Passage (DP), alongside the synergistic action of the westerly winds, led to a Southern Ocean transition from large, subpolar gyres to the onset of the Antarctic Circumpolar Current (ACC). However, the impact of the changing latitudinal position and strength of the wind stress in altering the early Southern Ocean circulation has been poorly addressed. Here, we use an eddy-permitting ocean model (0.25∘) with realistic late Eocene paleo-bathymetry to investigate the sensitivity of the Southern Ocean to paleo-latitudinal migrations (relative to the gateways) and strengthening of the wind stress. We find that southward wind stress shifts of 5 or 10∘, with a shallow TG (300 m), lead to dominance of subtropical waters in the high latitudes and further warming of the Antarctic coast (increase by 2 ∘C). Southward migrations of wind stress with a deep TG (1500 m) cause the shrinking of the subpolar gyres and cooling of the surface waters in the Southern Ocean (decrease by 3–4 ∘C). With a 1500 m deep TG and maximum westerly winds aligning with both the TG and DP, we observe a proto-ACC with a transport of ∼47.9 Sv. This impedes the meridional transport of warm subtropical waters to the Antarctic coast, thus laying a foundation for thermal isolation of the Antarctic. Intriguingly, proto-ACC flow through the TG is much more sensitive to strengthened wind stress compared to the DP. We suggest that topographic form stress can balance surface wind stress at depth to support the proto-ACC while the sensitivity of the transport is likely associated with the momentum budget between wind stress and near-surface topographic form stress driven by the subtropical gyres. In summary, this study proposes that the cooling of Eocene Southern Ocean is a consequence of a combination of gateway deepening and the alignment of maximum wind stress with both gateways.
Australian-Antarctic breakup and seafloor spreading: Balancing geological and geophysical constraints
Publisher: Elsevier BV
Date: 2019
Community infrastructure and repository for marine magnetic identifications
Publisher: American Geophysical Union (AGU)
Date: 04-2014
DOI: 10.1002/2013GC005176
Seismic facies and stratigraphy of the Cenozoic succession in McMurdo Sound, Antarctica: Implications for tectonic, climatic and glacial history
Publisher: Elsevier BV
Date: 04-2008
Semiautomatic fracture zone tracking
Publisher: American Geophysical Union (AGU)
Date: 07-2015
DOI: 10.1002/2015GC005853
Deepening of Southern Ocean Gateway Leads to Abrupt Onset of a Deep‐Reaching Meridional Overturning Circulation
Publisher: American Geophysical Union (AGU)
Date: 04-10-2023
DOI: 10.1029/2023GL104382
The breakup of East Gondwana: Assimilating constraints from Cretaceous ocean basins around India into a best-fit tectonic model
Publisher: American Geophysical Union (AGU)
Date: 03-2013
DOI: 10.1002/JGRB.50079
Onset of Antarctic Circumpolar Current 30 million years ago as Tasmanian Gateway aligned with westerlies
Publisher: Springer Science and Business Media LLC
Date: 07-2015
DOI: 10.1038/NATURE14598
Abstract: Earth's mightiest ocean current, the Antarctic Circumpolar Current (ACC), regulates the exchange of heat and carbon between the ocean and the atmosphere, and influences vertical ocean structure, deep-water production and the global distribution of nutrients and chemical tracers. The eastward-flowing ACC occupies a unique circumglobal pathway in the Southern Ocean that was enabled by the tectonic opening of key oceanic gateways during the break-up of Gondwana (for ex le, by the opening of the Tasmanian Gateway, which connects the Indian and Pacific oceans). Although the ACC is a key component of Earth's present and past climate system, the timing of the appearance of diagnostic features of the ACC (for ex le, low zonal gradients in water-mass tracer fields) is poorly known and represents a fundamental gap in our understanding of Earth history. Here we show, using geophysically determined positions of continent-ocean boundaries, that the deep Tasmanian Gateway opened 33.5 ± 1.5 million years ago (the errors indicate uncertainty in the boundary positions). Following this opening, sediments from Indian and Pacific cores recorded Pacific-type neodymium isotope ratios, revealing deep westward flow equivalent to the present-day Antarctic Slope Current. We observe onset of the ACC at around 30 million years ago, when Southern Ocean neodymium isotopes record a permanent shift to modern Indian-Atlantic ratios. Our reconstructions of ocean circulation show that massive reorganization and homogenization of Southern Ocean water masses coincided with migration of the northern margin of the Tasmanian Gateway into the mid-latitude westerly wind band, which we reconstruct at 64° S, near to the northern margin. Onset of the ACC about 30 million years ago coincided with major changes in global ocean circulation and probably contributed to the lower atmospheric carbon dioxide levels that appear after this time.
Early India‐Australia spreading history revealed by newly detected Mesozoic magnetic anomalies in the Perth Abyssal Plain
Publisher: American Geophysical Union (AGU)
Date: 07-2013
DOI: 10.1002/JGRB.50239
Abstract: The seafloor within the Perth Abyssal Plain (PAP), offshore Western Australia, is the only section of crust that directly records the early spreading history between India and Australia during the Mesozoic breakup of Gondwana. However, this early spreading has been poorly constrained due to an absence of data, including marine magnetic anomalies and data constraining the crustal nature of key tectonic features. Here, we present new magnetic anomaly data from the PAP that shows that the crust in the western part of the basin was part of the Indian Plate—the conjugate flank to the oceanic crust immediately offshore the Perth margin, Australia. We identify a sequence of M2 and older anomalies in the west PAP within crust that initially moved with the Indian Plate, formed at intermediate half‐spreading rates (35 mm/yr) consistent with the conjugate sequence on the Australian Plate. More speculatively, we reinterpret the youngest anomalies in the east PAP, finding that the M0‐age crust initially formed on the Indian Plate was transferred to the Australian Plate by a westward jump or propagation of the spreading ridge shortly after M0 time. S les dredged from the Gulden Draak and Batavia Knolls (at the western edge of the PAP) reveal that these bathymetric features are continental fragments rather than igneous plateaus related to Broken Ridge. These microcontinents rifted away from Australia with Greater India during initial breakup at ~130 Ma, then rifted from India following the cessation of spreading in the PAP (~101–103 Ma).
Ridge subduction sparked reorganization of the Pacific plate‐mantle system 60–50 million years ago
Publisher: American Geophysical Union (AGU)
Date: 24-03-2015
DOI: 10.1002/2015GL063057
Gateway-driven weakening of ocean gyres leads to Southern Ocean cooling
Publisher: Springer Science and Business Media LLC
Date: 09-11-2021
DOI: 10.1038/S41467-021-26658-1
Abstract: Declining atmospheric CO 2 concentrations are considered the primary driver for the Cenozoic Greenhouse-Icehouse transition, ~34 million years ago. A role for tectonically opening Southern Ocean gateways, initiating the onset of a thermally isolating Antarctic Circumpolar Current, has been disputed as ocean models have not reproduced expected heat transport to the Antarctic coast. Here we use high-resolution ocean simulations with detailed paleobathymetry to demonstrate that tectonics did play a fundamental role in reorganising Southern Ocean circulation patterns and heat transport, consistent with available proxy data. When at least one gateway (Tasmanian or Drake) is shallow (300 m), gyres transport warm waters towards Antarctica. When the second gateway subsides below 300 m, these gyres weaken and cause a dramatic cooling (average of 2–4 °C, up to 5 °C) of Antarctic surface waters whilst the ACC remains weak. Our results demonstrate that tectonic changes are crucial for Southern Ocean climate change and should be carefully considered in constraining long-term climate sensitivity to CO 2 .
A new heat flux model for the Antarctic Peninsula incorporating spatially variable upper crustal radiogenic heat production
Publisher: American Geophysical Union (AGU)
Date: 12-06-2017
DOI: 10.1002/2017GL073596
Kinematics of Footwall Exhumation at Oceanic Detachment faults: Solid‐Block Rotation and Apparent Unbending
Publisher: American Geophysical Union (AGU)
Date: 04-2021
DOI: 10.1029/2021GC009681
Abstract: Seafloor spreading at slow rates can be accommodated on large‐offset oceanic detachment faults (ODFs), that exhume lower crustal and mantle rocks in footwall domes termed oceanic core complexes (OCCs). Footwall rocks experience large rotation during exhumation, yet important aspects of the kinematics—particularly the relative roles of solid‐block rotation and flexure—are not clearly understood. Using a high‐resolution numerical model, we explore the exhumation kinematics in the footwall beneath an emergent ODF/OCC. A key feature of the models is that footwall motion is dominated by solid‐block rotation, accommodated by the nonplanar, concave‐down fault interface. A consequence is that curvature measured along the ODF is representative of a neutral stress configuration, rather than a “bent” one. Instead, it is in the subsequent process of “apparent unbending” that significant flexural stresses are developed in the model footwall. The brittle strain associated with apparent unbending is produced dominantly in extension, beneath the OCC, consistent with earthquake clustering observed in the Trans‐Atlantic Geotraverse at the Mid‐Atlantic Ridge.
Plateaus from seafloor spreading
Publisher: Springer Science and Business Media LLC
Date: 08-07-2019
Southern Ocean biogenic blooms freezing-in Oligocene colder climates
Publisher: Springer Science and Business Media LLC
Date: 09-11-2022
DOI: 10.1038/S41467-022-34623-9
Abstract: Crossing a key atmospheric CO 2 threshold triggered a fundamental global climate reorganisation ~34 million years ago (Ma) establishing permanent Antarctic ice sheets. Curiously, a more dramatic CO 2 decline (~800–400 ppm by the Early Oligocene(~27 Ma)), postdates initial ice sheet expansion but the mechanisms driving this later, rapid drop in atmospheric carbon during the early Oligocene remains elusive and controversial. Here we use marine seismic reflection and borehole data to reveal an unprecedented accumulation of early Oligocene strata (up to 2.2 km thick over 1500 × 500 km) with a major biogenic component in the Australian Southern Ocean. High-resolution ocean simulations demonstrate that a tectonically-driven, one-off reorganisation of ocean currents, caused a unique period where current instability coincided with high nutrient input from the Antarctic continent. This unrepeated and short-lived environment favoured extreme bioproductivity and enhanced sediment burial. The size and rapid accumulation of this sediment package potentially holds ~1.067 × 10 15 kg of the ‘missing carbon’ sequestered during the decline from an Eocene high CO 2 -world to a mid-Oligocene medium CO 2 -world, highlighting the exceptional role of the Southern Ocean in modulating long-term climate.
Major Australian-Antarctic Plate Reorganization at Hawaiian-Emperor Bend Time
Publisher: American Association for the Advancement of Science (AAAS)
Date: 05-10-2007
Abstract: A marked bend in the Hawaiian-Emperor seamount chain supposedly resulted from a recent major reorganization of the plate-mantle system there 50 million years ago. Although alternative mantle-driven and plate-shifting hypotheses have been proposed, no contemporaneous circum-Pacific plate events have been identified. We report reconstructions for Australia and Antarctica that reveal a major plate reorganization between 50 and 53 million years ago. Revised Pacific Ocean sea-floor reconstructions suggest that subduction of the Pacific-Izanagi spreading ridge and subsequent Marianas/Tonga-Kermadec subduction initiation may have been the ultimate causes of these events. Thus, these plate reconstructions solve long-standing continental fit problems and improve constraints on the motion between East and West Antarctica and global plate circuit closure.
The Louisiade ophiolite: A missing link in the western Pacific
Publisher: Wiley
Date: 06-02-2022
DOI: 10.1111/TER.12578
Abstract: Recent dredging of a 100 km long ridge along the northernmost part of the Louisiade Plateau (LP) recovered serpentinized peridotites, MORB (mid‐ocean‐ridge basalt) and volcaniclastic breccia–conglomerates. Clinopyroxene, Cr‐spinel and bulk rocks show that the serpentinites are harzburgites to dunites, whereas hornblende phenocrysts from volcaniclastic rocks reflect hydrous, andesitic volcanism. The association of MORB, depleted mantle rocks and fingerprints of hydrous arc magmatism is typical of supra‐subduction zone ocean lithosphere formed above a nascent subduction zone. Seismic and high‐resolution bathymetry data reveal structures consistent with an extensive east–west elongated ophiolite estimated to have obducted onto the LP between 53 and 80 Ma. This represents a major eastwards continuation of the Papuan Ultramafic Belt and forms a crucial link with ophiolites farther south in New Caledonia, providing support for major subduction initiation events in marginal basins along the northern and eastern margins of Australia and Zealandia in the Palaeocene–Eocene.
The tectonic fabric of the ocean basins
Publisher: American Geophysical Union (AGU)
Date: 24-12-2011
DOI: 10.1029/2011JB008413
Cenozoic lithospheric deformation in Northeast Asia and the rapidly-aging Pacific Plate
Publisher: Elsevier BV
Date: 06-2018
Submarine sedimentary bedforms and benthos surrounding the Heard and McDonald Islands World Heritage site
Publisher: Elsevier
Date: 2020
Sunda-Java trench kinematics, slab window formation and overriding plate deformation since the Cretaceous
Publisher: Elsevier BV
Date: 03-2007
Deep convection as the key to the transition from Eocene to modern Antarctic Circumpolar Current
Publisher: Authorea, Inc.
Date: 08-07-2023
DOI: 10.22541/ESSOAR.168881813.35699121/V1
Abstract: From the Eocene (~50 million years ago) to today, Southern Ocean circulation has evolved from the existence of two ocean gyres to the dominance of the Antarctic Circumpolar Current (ACC). It has generally been thought that the opening of Southern Ocean gateways in the late Eocene, in addition to the alignment of westerly winds with these gateways or the presence of Antarctic ice sheet, was a sufficient requirement for the transition to an ACC of similar strength to its modern equivalent. Nevertheless, models representing these changes produce only a much weaker ACC. Here we show, using an eddying ocean model, that the missing ingredient in the transition to a modern ACC is deep convection around the Antarctic continent. This deep convection is caused by cold temperatures and high salinities due to sea-ice production around the Antarctic continent, leading to both the formation of Antarctic Bottom Water and a modern-strength ACC.
Global sediment thickness data set updated for the Australian‐Antarctic Southern Ocean
Publisher: American Geophysical Union (AGU)
Date: 08-2013
DOI: 10.1002/GGGE.20181
Antarctic Sedimentary Basins and Their Influence on Ice‐Sheet Dynamics
Publisher: American Geophysical Union (AGU)
Date: 31-08-2023
DOI: 10.1029/2021RG000767
Abstract: Knowledge of Antarctica's sedimentary basins builds our understanding of the coupled evolution of tectonics, ice, ocean, and climate. Sedimentary basins have properties distinct from basement‐dominated regions that impact ice‐sheet dynamics, potentially influencing future ice‐sheet change. Despite their importance, our knowledge of Antarctic sedimentary basins is restricted. Remoteness, the harsh environment, the overlying ice sheet, ice shelves, and sea ice all make fieldwork challenging. Nonetheless, in the past decade the geophysics community has made great progress in internationally coordinated data collection and compilation with parallel advances in data processing and analysis supporting a new insight into Antarctica's subglacial environment. Here, we summarize recent progress in understanding Antarctica's sedimentary basins. We review advances in the technical capability of radar, potential fields, seismic, and electromagnetic techniques to detect and characterize basins beneath ice and advances in integrated multi‐data interpretation including machine‐learning approaches. These new capabilities permit a continent‐wide mapping of Antarctica's sedimentary basins and their characteristics, aiding definition of the tectonic development of the continent. Crucially, Antarctica's sedimentary basins interact with the overlying ice sheet through dynamic feedbacks that have the potential to contribute to rapid ice‐sheet change. Looking ahead, future research directions include techniques to increase data coverage within logistical constraints, and resolving major knowledge gaps, including insufficient s ling of the ice‐sheet bed and poor definition of subglacial basin structure and stratigraphy. Translating the knowledge of sedimentary basin processes into ice‐sheet modeling studies is critical to underpin better capacity to predict future change.
Antarctic Geothermal Heat Flow Model: Aq1
Publisher: American Geophysical Union (AGU)
Date: 02-2021
DOI: 10.1029/2020GC009428
Abstract: We present a refined map of geothermal heat flow for Antarctica, Aq1, based on multiple observables. The map is generated using a similarity detection approach by attributing observables from geophysics and geology to a large number of high‐quality heat flow values ( N = 5,792) from other continents. Observables from global, continental, and regional datasets for Antarctica are used with a weighting function that allows the degree of similarity to increase with proximity and how similar the observables are. The similarity detection parameters are optimized through cross correlation. For each grid cell in Antarctica, a weighted average heat flow value and uncertainty metrics are calculated. The Aq1 model provides higher spatial resolution in comparison to previous results. High heat flow is shown in the Thwaites Glacier region, with local values over 150 mW m −2 . We also map elevated values over 80 mW m −2 in Palmer Land, Marie Byrd Land, Victoria Land and Queen Mary Land. Very low heat flow is shown in the interior of Wilkes Land and Coats Land, with values under 40 mW m −2 . We anticipate that the new geothermal heat flow map, Aq1, and its uncertainty bounds will find extended use in providing boundary conditions for ice sheet modeling and understanding the interactions between the cryosphere and solid Earth. The computational framework and open architecture allow for the model to be reproduced, adapted and updated with additional data, or model subsets to be output at higher resolution for regional studies.
Tectonics: The hydrangeas of plate tectonics
Publisher: Springer Science and Business Media LLC
Date: 04-2009
DOI: 10.1038/NGEO492
Discovery of a microcontinent (Gulden Draak Knoll) offshore Western Australia: Implications for East Gondwana reconstructions
Publisher: Elsevier BV
Date: 10-2015
Constraining the Jurassic extent of Greater India: Tectonic evolution of the West Australian margin
Publisher: American Geophysical Union (AGU)
Date: 05-2012
DOI: 10.1029/2011GC003919
Kinematics of footwall exhumation at oceanic detachment faults: solid-block rotation and apparent unbending
Publisher: Wiley
Date: 06-02-2021
A Global Data Set of Present‐Day Oceanic Crustal Age and Seafloor Spreading Parameters
Publisher: American Geophysical Union (AGU)
Date: 10-2020
DOI: 10.1029/2020GC009214
Longest continuously erupting large igneous province driven by plume-ridge interaction
Publisher: Geological Society of America
Date: 07-10-2021
DOI: 10.1130/G47850.1
Abstract: Large igneous provinces (LIPs) typically form in one short pulse of ∼1–5 Ma or several punctuated ∼1–5 Ma pulses. Here, our 25 new 40Ar/39Ar plateau ages for the main construct of the Kerguelen LIP—the Cretaceous Southern and Central Kerguelen Plateau, Elan Bank, and Broken Ridge—show continuous volcanic activity from ca. 122 to 90 Ma, a long lifespan of & Ma. This suggests that the Kerguelen LIP records the longest, continuous high-magma-flux emplacement interval of any LIP. Distinct from both short-lived and multiple-pulsed LIPs, we propose that Kerguelen is a different type of LIP that formed through long-term interactions between a mantle plume and mid-ocean ridge, which is enabled by multiple ridge jumps, slow spreading, and migration of the ridge. Such processes allow the transport of magma products away from the eruption center and result in long-lived, continuous magmatic activity.
Development of the Australian-antarctic depth anomaly
Publisher: American Geophysical Union (AGU)
Date: 11-2010
DOI: 10.1029/2010GC003276
Naturaliste Plateau: constraints on the timing and evolution of the Kerguelen Large Igneous Province and its role in Gondwana breakup
Publisher: Informa UK Limited
Date: 03-10-2017
Fingerprinting Proterozoic Bedrock in Interior Wilkes Land, East Antarctica
Publisher: Springer Science and Business Media LLC
Date: 15-07-2019
DOI: 10.1038/S41598-019-46612-Y
Abstract: Wilkes Land in East Antarctica remains one of the last geological exploration frontiers on Earth. Hidden beneath kilometres of ice, its bedrock preserves a poorly-understood tectonic history that mirrors that of southern Australia and holds critical insights into past supercontinent cycles. Here, we use new and recently published Australian and Antarctic geological and geophysical data to present a novel interpretation of the age and character of crystalline basement and sedimentary cover of interior Wilkes Land. We combine new zircon U–Pb and Hf isotopic data from remote Antarctic outcrops with aeromagnetic data observations from the conjugate Australian-Antarctic margins to identify two new Antarctic Mesoproterozoic basement provinces corresponding to the continuation of the Coompana and Madura provinces of southern Australia into Wilkes Land. Using both detrital zircon U–Pb–Hf and authigenic monazite U–Th–Pb isotopic data from glacial erratic sandstone s les, we identify the presence of Neoproterozoic sedimentary rocks covering Mesoproterozoic basement. Together, these new geological insights into the ice-covered bedrock of Wilkes Land substantially improve correlations of Antarctic and Australian geological elements and provide key constraints on the tectonic architecture of this sector of the East Antarctic Shield and its role in supercontinent reconstructions.
Tectonic drivers and the influence of the Kerguelen plume on seafloor spreading during formation of the early Indian Ocean
Publisher: Elsevier BV
Date: 07-2016
Insights on the kinematics of the India‐Eurasia collision from global geodynamic models
Publisher: American Geophysical Union (AGU)
Date: 04-2012
DOI: 10.1029/2011GC003883
The Antarctic Crust and Upper Mantle: A Flexible 3D Model and Software Framework for Interdisciplinary Research
Publisher: Frontiers Media SA
Date: 27-11-2020
DOI: 10.3389/FEART.2020.577502
Abstract: Interdisciplinary research concerning solid Earth–cryosphere interaction and feedbacks requires a working model of the Antarctic crust and upper mantle. Active areas of interest include the effect of the heterogeneous Earth structure on glacial isostatic adjustment, the distribution of geothermal heat, and the history of erosion and deposition. In response to this research need, we construct an adaptable and updatable 3D grid model in a software framework to contain and process solid Earth data. The computational framework, based on an open source software package agrid , allows different data sources to be combined and jointly analyzed. The grid model is populated with crustal properties from geological observations and geochronology results, where such data exist, and published segmentation from geophysical data in the interior where direct observations are absent. The grid also contains 3D geophysical data such as wave speed and derived temperature from seismic tomographic models, and 2D datasets such as gravity anomalies, surface elevation, subglacial temperature, and ice sheet boundaries. We demonstrate the usage of the framework by computing new estimates of subglacial steady-state heat flow in a continental scale model for east Antarctica and a regional scale model for the Wilkes Basin in Victoria Land. We hope that the 3D model and framework will be used widely across the solid Earth and cryosphere research communities.
Strike-slip tectonics during the Neoproterozoic–Cambrian assembly of East Gondwana: Evidence from a newly discovered microcontinent in the Indian Ocean (Batavia Knoll)
Publisher: Elsevier BV
Date: 11-2017
Eastern Indian Ocean microcontinent formation driven by plate motion changes
Publisher: Elsevier BV
Date: 11-2016
Impact of Deep Water Formation on Antarctic Circumpolar Transport During Gateway Opening
Publisher: Authorea, Inc.
Date: 21-12-2022
DOI: 10.22541/ESSOAR.167160849.98375746/V1
Abstract: Ambiguity over the Eocene opening times of the Tasman Gateway and Drake Passage makes it difficult to determine the initiation time of the Antarctic Circumpolar Current (ACC). If the Tasman Gateway opened later than Drake Passage, then Australia may have prevented the proto-ACC from forming. Recent modelling results have shown that only a relatively weak circumpolar transport results under Eocene surface forcing. This leads to warm and buoyant coastal water around Antarctica, which may impede the formation of deep waters and convective processes. This suggests that a change in deep water formation might be required to increase the density contrast across the Southern Ocean and increase circumpolar transport.Here we use a simple reduced gravity model with two basins, to represent the Atlantic and the Pacific. This fixes the density difference between surface and deep water and allows us to isolate the impact of deep water formation on circumpolar transport. With no obstacle on the southern boundary the circumpolar current increases its transport from 82.3 to 270.0 Sv with deep water formation. Placing an Antipodean landmass on the southern boundary reduces this transport as the landmass increases in size. However, circumpolar flow north of this landmass remains a possibility even without deep water formation. Weak circumpolar transport continues until the basin is completely blocked by the Antipodes. When the Antipodes is instead allowed to split from the southern boundary, circumpolar transport recovers to its unobstructed value. Flow rapidly switches to south of the Antipodes when the gateway is narrow.
A cryptic Gondwana-forming orogen located in Antarctica
Publisher: Springer Science and Business Media LLC
Date: 30-05-2018
DOI: 10.1038/S41598-018-26530-1
Abstract: The most poorly exposed and least understood Gondwana-forming orogen lies largely hidden beneath ice in East Antarctica. Called the Kuunga orogen, its interpolation between scattered outcrops is speculative with differing and often contradictory trends proposed, and no consensus on the location of any sutures. While some discount a suture altogether, paleomagnetic data from Indo-Antarctica and Australo-Antarctica do require 3000–5000 km relative displacement during Ediacaran-Cambrian Gondwana amalgamation, suggesting that the Kuunga orogen sutured provinces of broadly Indian versus Australian affinity. Here we use compiled data from detrital zircons offshore of East Antarctica that fingerprint two coastal subglacial basement provinces between 60 and 130°E, one of Indian affinity with dominant ca. 980–900 Ma ages (Indo-Antarctica) and one of Australian affinity with dominant ca. 1190–1140 and ca. 1560 Ma ages (Australo-Antarctica). We combine this offshore compilation with existing and new onshore U-Pb geochronology and previous geophysical interpretations to delimit the Indo-Australo-Antarctic boundary at a prominent geophysical lineament which intersects the coast east of Mirny at ~94°E.
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