Academic Staff
Phone: +61 2 9351 8904
Madsen Building F09, Room 404See below for EarthByte content related to Simon.
AGU Science News: Billion-Year Rewind Tracks Supercontinents and Mantle Structures – EOS has featured our recent paper on tracing past pathways of tectonic plates and their boundaries back a billion years. The article highlights how our work on solid Earth system evolution is driving “a second plate tectonic revolution”., inspiring future work to test and … Read more…
Modern ocean biodiversity, which is at its highest level ever, was achieved through long-term stability of the location of so-called biodiversity hotspots, regions of especially high numbers of species, scientists have found. The findings, published in Nature, were reached through a pioneering model that reconstructs the diversity of marine animals from their origin – some … Read more…
The fossil record of marine invertebrates has long fuelled the debate as to whether or not there are limits to global diversity in the sea. Ecological theory states that, as diversity grows and ecological niches are filled, the strengthening of biological interactions imposes limits on diversity. However, the extent to which biological interactions have constrained … Read more…
Understanding the long-term evolution of Earth’s plate-mantle system is reliant on absolute plate motion models in a mantle reference frame, but such models are both difficult to construct and controversial. We present a tectonic rules-based optimisation approach to construct a plate motion model in a mantle reference frame covering the last billion years and use … Read more…
Recent progress in plate tectonic reconstructions has seen models move beyond the classical idea of continental drift by attempting to reconstruct the full evolving configuration of tectonic plates and plate boundaries. A particular problem for the Neoproterozoic and Cambrian is that many existing interpretations of geological and palaeomagnetic data have remained disconnected from younger, better-constrained … Read more…
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 number … Read more…
The sedimentary rock record suggests that global sea levels may have fluctuated by hundreds of meters throughout Phanerozoic times. Long-term (10–80 Myr) sea level change can be inferred from paleogeographic reconstructions and stratigraphic methods can be used to estimate sea level change over 1–10 Myr in tectonically quiescent regions assumed to be stable. Plate tectonic … Read more…
GPlates is a free desktop software for the interactive visualisation of plate-tectonics. The compilation and documentation of GPlates 2.3 data was primarily funded by AuScope National Collaborative Research Infrastructure (NCRIS).
GPlates is developed by the EarthByte Group (part of AuScope NCRIS) at the University of Sydney and the Division of Geological and Planetary Sciences (GPS) at California Institute of Technology (CalTech). … Read more…
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…
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…
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…
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…
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…
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…
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…
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…
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…
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 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…
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…
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…
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…
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…
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…
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…
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 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…
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…
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…
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…
