Dr Simon Williams

Simon Williams on the Southern SurveyorAcademic Staff

simon.williams@sydney.edu.au

Phone: +61 2 9351 8904

Madsen Building F09, Room 404
School of Geosciences
The University of Sydney
Sydney, NSW 2006
Australia

View Simon’s Sydney Uni page

See below for EarthByte content related to Simon.

Subduction history reveals Cretaceous slab superflux as a possible cause for the mid-Cretaceous plume pulse and superswell events

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Abstract: Subduction is a fundamental mechanism of material exchange between the planetary interior and the surface. Despite its significance, our current understanding of fluctuating subducting plate area and slab volume flux has been limited to a range of proxy estimates. Here we present a new detailed quantification of subduction zone parameters from the Late Triassic … Read more…

East African topography and volcanism explained by a single, migrating plume

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Abstract: Anomalous topographic swells and Cenozoic volcanism in east Africa have been associated with mantle plumes. Several models involving one or more fixed plumes beneath the northeastward migrating African plate have been suggested to explain the space-time distribution of magmatism in east Africa. We devise paleogeographically constrained global models of mantle convection and, based on … Read more…

Reconstructing seafloor age distributions in lost ocean basins

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Abstract: Reconstructions of past seafloor age make it possible to quantify how plate tectonic forces, surface heat flow, ocean basin volume and global sea-level have varied through geological time. However, past ocean basins that have now been subducted cannot be uniquely reconstructed, and a significant challenge is how to explore a wide range of possible … Read more…

A global dataset of present-day oceanic crustal age and seafloor spreading parameters

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Abstract: We present an updated oceanic crustal age grid and a set of complementary grids including spreading rate, asymmetry, direction and obliquity. Our dataset is based on a selected set of magnetic anomaly identifications and the plate tectonic model of Müller et al. (2019). We find the mean age of oceanic crust is 64.2 Myrs, … Read more…

Kinematic and geodynamic evolution of the Isthmus of Panama region: Implications for Central American Seaway closure

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Abstract: A major topic of debate in Earth and climate science surrounds the timing of closure of the Central American Seaway. While it is clear that the gateway was closed by ~2.8 Ma, recent studies based on geological and marine molecular evidence have suggested an earlier closing time of early to mid-Miocene. Here, we examine … Read more…

Sea level fluctuations driven by changes in global ocean basin volume following supercontinent break-up

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Abstract: Long-term variations in eustatic sea level in an ice-free world, which existed through most of the Mesozoic and early Cenozoic eras, are partly driven by changes in the volume of ocean basins. Previous studies have determined ocean basin volume changes from plate tectonic reconstructions since the Mesozoic; however, these studies have not considered a … Read more…

Paper in Geological Society London Memoirs: Geodynamics of the SW Pacific: a brief review and relations with New Caledonian geology

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A book chapter in: New Caledonia: Geology, Geodynamic Evolution and Mineral Resources. Geological Society, London, Memoirs, 51, 13–26, https://doi.org/10.1144/M51-2018-5 has finally been published. The book chapter, which gives a brief overview of the geodynamics of New Caledonia, was a collaboration between colleagues from New Caledonia, New Zealand, Australia and France. Abstract below: The SW Pacific … Read more…

The interplay of dynamic topography and eustasy on continental flooding in the late Paleozoic

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Abstract: Global sea level change can be inferred from sequence stratigraphic and continental flooding data. These methods reconstruct sea level from peri-cratonic and cratonic basins that are assumed to be tectonically stable and sometimes called reference districts, and from spatio-temporal correlations across basins. However, it has been understood that long-wavelength (typically hundreds of km) and low-amplitude … Read more…

Constraining Absolute Plate Motions Since the Triassic

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Abstract: The absolute motion of tectonic plates since Pangea can be derived from observations of hotspot trails, paleomagnetism, or seismic tomography. However, fitting observations is typically carried out in isolation without consideration for the fit to unused data or whether the resulting plate motions are geodynamically plausible. Through the joint evaluation of global hotspot track … Read more…

Decoding earth’s plate tectonic history using sparse geochemical data

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Abstract: Accurately mapping plate boundary types and locations through time is essential for understanding the evolution of the plate-mantle system and the exchange of material between the solid Earth and surface environments. However, the complexity of the Earth system and the cryptic nature of the geological record make it difficult to discriminate tectonic environments through … Read more…

GPlates 2.2 software and data sets

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GPlates 1.5 PromoGPlates is a free desktop software for the interactive visualisation of plate-tectonics. The compilation and documentation of GPlates 2.2 data was primarily funded by AuScope National Collaborative Research Infrastructure (NCRIS).

GPlates is developed by an international team of scientists and professional software developers at the EarthByte Project (part of AuScope) at the University of Sydney, the Division of Geological and Planetary Sciences (GPS) at CalTech, the Geodynamics team at the Geological Survey of Norway (NGU) and the Centre for Earth Evolution and Dynamics (CEED) at the University of Oslo. … Read more…

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The interplay of dynamic topography and eustasy on continental flooding in the late Paleozoic

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Abstract: Global sea level change can be inferred from sequence stratigraphic and continental flooding data. These methods reconstruct sea level from peri-cratonic and cratonic basins that are assumed to be tectonically stable and sometimes called reference districts, and from spatio-temporal correlations across basins. However, it has been understood that long-wavelength (typically hundreds of km) and … Read more…

Magma production along the Lord Howe Seamount Chain, northern Zealandia

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Citation: Seton, M, Williams, S.E., Mortimer, N., Meffre, S., Micklethwaite, S., Zahirovic, S., 2019, Magma production along the Lord Howe Seamount Chain, northern Zealandia, Geological Magazine, 1-13, https://doi.org/10.1017/S0016756818000912 Abstract: One of the world’s most notable intraplate volcanic regions lies on the eastern Australian plate and includes two age-progressive trails offshore (Tasmantid and Lord Howe seamount chains) and the … Read more…

Rift and plate boundary evolution across two supercontinent cycles

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Citation: Merdith, Andrew & Williams, Simon & Brune, Sascha & Collins Alan, S & Müller, Dietmar. (2018). Rift and plate boundary evolution across two supercontinent cycles. Global and Planetary Change. 173. 10.1016/j.gloplacha.2018.11.006. Abstract The extent of continental rifts and subduction zones through deep geological time provides insights into the mechanisms behind supercontinent cycles and the long term evolution of the mantle. … Read more…

Rift and plate boundary evolution across two super-continent cycles

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Abstract The extent of continental rifts and subduction zones through deep geological time provides insights into the mechanisms behind supercontinent cycles and the long term evolution of the mantle. However, previous compilations have stopped short of mapping the locations of rifts and subduction zones continuously since the Neoproterozoic and within a self-consistent plate kinematic framework. … Read more…

Australian-Antarctic breakup and seafloor spreading: Balancing geological and geophysical constraints

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Abstract  The motion of diverging tectonic plates is typically constrained by geophysical data from preserved ocean crust. However, constraining plate motions during continental rifting and the breakup process relies on balancing evidence from a diverse range of geological and geophysical observations, often subject to differing interpretations. Reconstructing the evolution of rifting and breakup between Australia and Antarctica epitomizes the challenges involved in … Read more…

Oblique rifting: the rule, not the exception

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Abstract: Movements of tectonic plates often induce oblique deformation at divergent plate boundaries. This is in striking contrast with traditional conceptual models of rifting and rifted margin formation, which often assume 2-D deformation where the rift velocity is oriented perpendicular to the plate boundary. Here we quantify the validity of this assumption by analysing the kinematics … Read more…

New interactive rift obliquity globe on the GPlates Portal

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The ARC Basin Genesis Hub has made a new interactive rift obliquity globe available on the GPlates Portal at http://portal.gplates.org/cesium/?view=rift_ov, based on a recently published paper entitled “Oblique rifting: the rule, not the exception” in Solid Earth. This virtual globe visualizes extension velocities and obliquities within Earth’s major post-Pangea rift systems. Each circle depicts the … Read more…

GPlates 2.1 software and data sets

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GPlates Title Logo

GPlates 1.5 PromoGPlates is a free desktop software for the interactive visualisation of plate-tectonics. The compilation and documentation of GPlates 2.1 data was primarily funded by AuScope National Collaborative Research Infrastructure (NCRIS).

GPlates is developed by an international team of scientists and professional software developers at the EarthByte Project (part of AuScope) at the University of Sydney, the Division of Geological and Planetary Sciences (GPS) at CalTech, the Geodynamics team at the Geological Survey of Norway (NGU) and the Centre for Earth Evolution and Dynamics (CEED) at the University of Oslo. … Read more…

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PyBacktrack 1.0: a tool for reconstructing paleobathymetry on oceanic and continental crust

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The pyBacktrack software package allows the backtracking of the paleo-water depth of ocean drill sites, providing a framework for reconstructing the accumulation history of sediment components through time. The software incorporates the effects of decompaction of common marine lithologies and allows backtracking of sites on both oceanic and continental crust.  Backtracking on ocean crust is based on … Read more…

Regional volcanism of northern Zealandia: post-Gondwana break-up magmatism on an extended, submerged continent

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Abstract Abstract: Volcanism of Late Cretaceous–Miocene age is more widespread across the Zealandia continent than previously recognized. New age and geochemical information from widely spaced northern Zealandia seafloor samples can be related to three volcanotectonic regimes: (1) age-progressive, hotspot-style, low-K, alkali-basalt-dominated volcanism in the Lord Howe Seamount Chain. The northern end of the chain (c. … Read more…

Palaeolatitudinal distribution of lithologic indicators of climate in a palaeogeographic framework

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Citation: Cao, W., Williams, S., Flament, N., Zahirovic, S., Scotese, C., and Müller, R. D., 2018. Paleolatitudinal distribution of lithologic indicators of climate in a paleogeographic framework. Geological Magazine, 1-24. Abstract: Whether the latitudinal distribution of climate-sensitive lithologies is stable through greenhouse and icehouse regimes remains unclear. Previous studies suggest that the palaeolatitudinal distribution of palaeoclimate … Read more…

Improving global paleogeography since the late Paleozoic using paleobiology

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Author List: Wenchao Cao, Sabin Zahirovic, Nicolas Flament, Simon Williams, Jan Golonka, Dietmar Müller Citation: Cao, W., Zahirovic, S., Flament, N., Williams, S., Golonka, J., and Müller, R. D., 2017, Improving global paleogeography since the late Paleozoic using paleobiology: Biogeosciences, v. 14, no. 23, p. 5425-5439. Paleogeographic maps, linked to plate tectonic reconstructions, are key components required for climate models … Read more…

Degassing from Continental Rifts Controls Earth’s Thermostat

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As a greenhouse gas, carbon dioxide in the atmosphere has played a major role in regulating Earth’s climate throughout its history. There are vast stores of carbon in the subsurface, but the global carbon cycle controls how much of that carbon enters the atmosphere. As methods for monitoring and tracking the carbon dioxide that moves … Read more…

EarthByte Honours and Masters Projects 2018

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EarthByte has now released a list of Honours/Masters projects to be offered in 2018. These projects are outlined below. Project Title Supervisor(s) Dynamic Earth models, landscape dynamics and basin evolution in Australasia Dietmar Müller, Sabin Zahirovic, Tristan Salles, Rohit Chandra, Sally Cripps (Centre for Translational Data Science) Incorporating modern plate tectonic reconstructions into box models of the deep-time deep-Earth … Read more…

A reconstruction of the Eurekan Orogeny incorporating deformation constraints

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Author List:  Austin Gion, Simon Williams, Dietmar Müller Citation: Gion, A.M., Williams, S.E. and Müeller, R.D., 2017. A reconstruction of the Eurekan Orogeny incorporating deformation constraints. Tectonics, 36(2), pp.304-320. Abstract: The Eurekan Orogeny records Paleogene convergence between Greenland and the Canadian Arctic. The complexity of the region, well represented by the disputed magnitude of Cenozoic sinistral displacement of … Read more…

A global review and digital database of large-scale extinct spreading centers

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Author List: Sarah MacLeod, Simon Williams, Kara Matthews, Dietmar Müller and Xiaodong Qin Citation: MacLeod, S.J., Williams, S.E., Matthews, K.J., Müller, R.D. and Qin, X., 2017. A global review and digital database of large-scale extinct spreading centers. Geosphere, pp.GES01379-1. Abstract: Extinct mid-ocean ridges record past plate boundary reorganizations, and identifying their locations is crucial to developing a better understanding of the … Read more…

Kinematic constraints on the Rodinia to Gondwana transition

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Author List: Andrew Merdith, Simon Williams, Dietmar Müller & Alan Collins. Citation: Merdith, Andrew & Williams, Simon & Müller, Dietmar & Collins, Alan. (2017). Kinematic constraints on the Rodinia-Gondwana transition. Precambrian Research. 299. . 10.1016/j.precamres.2017.07.013. Abstract: Earth’s plate tectonic history during the breakup of the supercontinent Pangea is well constrained from the seafloor spreading record, but evolving plate configurations during … Read more…

Origin and evolution of the deep thermochemical structure beneath Eurasia

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Author List: Nicolas Flament, Simon Williams, Dietmar Müller, Michael Gurnis & Dan Bower. Citation: Flament, Nicolas & Williams, Simon & Müller, Dietmar & Gurnis, Michael & J. Bower, Dan. (2017). Origin and evolution of the deep thermochemical structure beneath Eurasia. Nature Communications. 8. . 10.1038/ncomms14164. Abstract: A unique structure in the Earth’s lowermost mantle, the Perm Anomaly, was … Read more…

Global patterns in Earth’s dynamic topography since the Jurassic: the role of subducted slabs

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Author List: Michael Rubey, Sascha Brune, Christian Heine, Rhodri Davies, Simon Williams, and Dietmar Müller. Citation: Rubey, M., Brune, S., Heine, C., Davies, D. R., Williams, S. E., and Müller, R. D.: Global patterns in Earth’s dynamic topography since the Jurassic: the role of subducted slabs, Solid Earth, 8, 899-919, https://doi.org/10.5194/se-8-899-2017, 2017. Abstract: We evaluate the spatial … Read more…