Linking rift propagation barriers to excess magmatism at volcanic rifted margins

Koopmann etal 2014 Model EvolutionCitation
Koopman, H., Brune, S., Franke, D. and Breuer. 2014. Linking rift propagation barriers to excess magmatism at volcanic rifted margins. Geology (Pre-Issue Publication 15. Oct), doi: 10.1130/G36085.

Summary
Break-up–related extrusive magmatism, imaged in reflection seismic data as seaward-dipping reflectors (SDRs), extends sym- metrically along the volcanic margins of the Atlantic Ocean. Recent research found distinct along-margin variations in the distribution of SDRs, and abundance of volcanic material was found to be spatially linked to transfer fault systems. These segmented the propagating rift that later developed into the ocean, and are interpreted as rift propa- gation barriers. Based on these observations, we develop a numeri- cal model, which shows that rift-parallel mantle flow and locally enhanced rates of volcanism are the result of delays in rift propaga- tion and segmented opening. … Read more…

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New GPlates Portal available

GPlates Portal Figure

EarthByte have launched a new cloud-based GPlates Web Portal that was used by almost 40 000 users over the last long-weekend! It took GPlates software over ten years to get that many users, so this is a huge achievement and also makes GPlates accessible to a broader audience! The GPlates portal can be used to … Read more…

New global marine gravity model, Sandwell et al. (2014)

Indian Ocean View Westward from AustraliaCitation
Sandwell, D. T., Müller, R. D., Smith, W. H. F., Garcia, E. and Francis, R. 2014. New global marine gravity model from Cryo-Sat-2 and jason-1 reveals buried tectonic structure. Science, Vol. 346, 6205, pp. 65-67, doi: 10.1126/science.1258213.

Summary
New global marine gravity model from CryoSat-2 and Jason-1 reveals buried tectonic structure.

View the new gravity map in an online 3D portal!

Gravity models are powerful tools for mapping tectonic structures, especially in the deep ocean basins where the topography remains unmapped by ships or is buried by thick sediment. We combined new radar altimeter measurements from satellites CryoSat-2 and Jason-1 with existing data to construct a global marine gravity model that is two times more accurate than previous models. We found an extinct spreading ridge in the Gulf of Mexico, a … Read more…

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Post-Jurassic tectonic evolution of southeast Asia from Zahirovic et al. (2014)

Asia Zahirovic 20maCitation
Zahirovic, S., Seton, M., and Müller, R. D., (2014). The Cretaceous and Cenozoic tectonic evolution of Southeast Asia: Solid Earth (EGU).

Summary
Tectonic reconstructions of Southeast Asia have given rise to numerous controversies that include the accretionary history of Sundaland and the enigmatic tectonic origin of the Proto South China Sea. We assimilate a diversity of geological and geophysical observations into a new regional plate model, coupled to a global model, to address these debates.

Our approach takes into account terrane suturing and accretion histories, the location of subducted slabs imaged in mantle tomography in order to constrain the evolution of regional subduction zones, as well as plausible absolute and relative plate velocities and tectonic driving mechanisms. … Read more…

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The tectonic stress field evolution of India since the Oligocene

Muller etal India Paleostress Graphical AbstractCitation
Müller, R. D., Yatheesh, V., & Shuhail, M. (2014). The tectonic stress field evolution of India since the Oligocene. Gondwana Research.

Summary
We use a 2 dimensional finite element model with heterogeneous elastic strengths in continental areas to model the regional stress field orientation and relative magnitudes in and around India for 33 Ma, 20 Ma and the present day. The large-scale geological structure of India is embedded in our model by using published outlines of cratons, fold belts and basins, associated with estimates of their relative strengths, enabling the modelling of stress field deflections along interfaces between relatively strong and weak tectonic elements through time. … Read more…

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GPlates 1.4 now available to download

GPlates Version 1.4 has been released! This latest update of GPlates brings added functionality for the export of both numerical floating point-data and colour reconstructed rasters, for a user specified region and resolution. There is also greater flexibility for raster file import, with ERMapper, Erdas Imagine and GeoTIFF files now supported and geo-referencing is retained … Read more…

Geoscientific Model Development – A suite of early Eocene (~55 Ma) climate model boundary conditions

Herold_etal_2014_BIOME4

Herold, N., Buzan, J., Seton, M., Goldner, A., Green, J. A. M., Müller, R. D., Markwick, P., & Huber, M. (2014). A suite of early Eocene (~ 55 Ma) climate model boundary conditions. Geoscientific Model Development, 7(5), 2077-2090. doi: 10.5194/gmd-7-2077-2014.

A suite of early Eocene (~ 55 Ma) climate model boundary conditions

Supplementary data

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Topographic asymmetry of the South Atlantic from global models of mantle flow and lithospheric stretching

Flament et al EPSL 2014 - FigureCitation
Flament, N., Gurnis, M., Williams, S., Seton, M., Skogseid, J., Heine, C., & Müller, R. D. (2014). Topographic asymmetry of the South Atlantic from global models of mantle flow and lithospheric stretching. Earth and Planetary Science Letters, 387, 107-119. dx.doi.org/10.1016/j.epsl.2013.11.017.

Abstract
The relief of the South Atlantic is characterized by elevated passive continental margins along southern Africa and eastern Brazil, and by the bathymetric asymmetry of the southern oceanic basin where the western flank is much deeper than the eastern flank. We investigate the origin of these topographic features in the present and over time since the Jurassic with a model of global mantle flow and lithospheric deformation. The model progressively assimilates plate kinematics, plate boundaries and lithospheric age derived from global tectonic reconstructions with deforming plates, and predicts the evolution of mantle temperature, continental crustal thickness, long-wavelength dynamic topography, and isostatic topography. … Read more…

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The breakup of east Gondwana: assimilating constraints from Cretaceous ocean basins around India into a best-fit tectonic model, Gibbons et al. (2013)

Citation
Gibbons, A., Whittaker, J. and R. Dietmar Müller, (2013), The break up of East Gondwana: assimilating constraints from Cretaceous ocean basins around India into a best-fit tectonic model. Journal of Geophysical Research, 118, 1-15: doi:10.1002/jgrb.50079

East GondwanaSummary
Published models for the Cretaceous seafloor-spreading history of East Gondwana result in unlikely tectonic scenarios for at least one of the plate boundaries involved and/or violate particular constraints from at least one of the associated ocean basins. We link East Gondwana spreading corridors by integrating magnetic and gravity anomaly data from the Enderby Basin off East Antarctica within a regional plate kinematic framework to identify a conjugate series of east-west-trending magnetic anomalies, M4 to M0 (~126.7–120.4 Ma). … Read more…

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Seawater chemistry driven by supercontinent assembly, breakup and dispersal, Müller et al. (2013)

Muller etal Fig1 - Seawater Chemistry Driven by Supercontinental AssemblyCitation
Müller, R. D., Dutkiewicz, A., Seton, M. and Gaina, C. (2013). Seawater chemistry driven by supercontinent assembly, break-up and dispersal Geology. doi 10.1130/G34405.1.

Summary
Global oceans are known to have alternated between aragonite and calcite seas. These oscillations reflect changes in the Mg/Ca ratio of seawater, which control biomineralisation and the composition of marine carbonates and are thought to be caused by the time dependence of crustal accretion at mid-ocean ridge crests and associated high temperature mid-ocean ridge brine flux. Here we use global ocean basin reconstructions to demonstrate that these fluctuations are instead caused by the gradual growth and destruction of mid-ocean ridges and their relatively cool flanks during long-term tectonic cycles thus linking ocean chemistry to off-ridge low temperature hydrothermal flux. Early Jurassic aragonite seas were a consequence of supercontinent stability and minima in mid-ocean ridge length and basalt alteration. The break-up of Pangaea led to a gradual doubling in ridge length and a 50% increase in hydrothermal flux mainly through an enormous increase in ridge flank area, leading to enhanced alteration of basalt, lowered seawater Mg/Ca ratios and marine hypercalcification from 140 to 35 Ma. … Read more…

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A review of observations and models of dynamic topography

Citation
Flament, N., Gurnis, M., & Müller, R. D. (2013). A review of observations and models of dynamic topography. Lithosphere, 5(2), 189-210. doi: 10.1130/L245.1

Flament-et-al_fig1Summary
The topography of Earth is primarily controlled by lateral differences in the density structure of the crust and lithosphere. In addition to this isostatic topography, flow in the mantle induces deformation of its surface leading to dynamic topography. This transient deformation evolves over tens of millions of years, occurs at long wavelength, and is relatively small (<2 km) in amplitude. Here, we review the observational constraints and modeling approaches used to understand the amplitude, spatial pattern, and time dependence of dynamic topography. … Read more…

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The tectonic evolution of the Arctic since Pangea breakup: Integrating constraints from surface geology and geophysics with mantle structure

Shephard Arctic IconCitation
Shephard, G. E., Müller, R. D., & Seton, M. (2013). The tectonic evolution of the Arctic since Pangea breakup: Integrating constraints from surface geology and geophysics with mantle structure. Earth-Science Reviews, 124, 148-183. doi:10.1016/j.earscirev.2013.05.012

Summary
The tectonic evolution of the circum-Arctic, including the northern Pacific, Siberian and North American margins, since the Jurassic has been punctuated by the opening and closing of ocean basins, the accretion of autochthonous and allochthonous terranes and associated deformation. This complexity is expressed in the uncertainty of plate tectonic models of the region, with the time-dependent configurations and kinematic history remaining poorly understood. … Read more…

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Total sediment thickness of the World's Oceans & Marginal Seas, version 2

Sedthickv2 256x188This update replaces the original Total Sediment Thickness of the World’s Oceans & Marginal Seas (Divins, 2003).

Citation
Whittaker, J. M., Goncharov, A., Williams, S. E., Müller, R. D., & Leitchenkov, G. (2013). Global sediment thickness data set updated for the Australian‐Antarctic Southern Ocean. Geochemistry, Geophysics, Geosystems, 14(8), 3297-3305. doi: 10.1002/ggge.20181.

Summary
NGDC’s global ocean sediment thickness grid (Divins, 2003) has been updated for the Australian-Antarctic region (60°-155°E, 30°-70°S). New seismic reflection and refraction data have been used to add detail to the conjugate Australian and Antarctic margins and intervening ocean floor where previously regional sediment thickness patterns were poorly known.  … Read more…

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Total sediment thickness of the World’s Oceans & Marginal Seas, version 2

Sedthickv2 256x188This update replaces the original Total Sediment Thickness of the World’s Oceans & Marginal Seas (Divins, 2003).

Citation
Whittaker, J. M., Goncharov, A., Williams, S. E., Müller, R. D., & Leitchenkov, G. (2013). Global sediment thickness data set updated for the Australian‐Antarctic Southern Ocean. Geochemistry, Geophysics, Geosystems, 14(8), 3297-3305. doi: 10.1002/ggge.20181.

Summary
NGDC’s global ocean sediment thickness grid (Divins, 2003) has been updated for the Australian-Antarctic region (60°-155°E, 30°-70°S). New seismic reflection and refraction data have been used to add detail to the conjugate Australian and Antarctic margins and intervening ocean floor where previously regional sediment thickness patterns were poorly known.  … Read more…

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GPlates legacy data and documentation

GPlates legacy image*Superceded (older) tutorials for earlier GPlates versions can still be accessed here

GPlates-compatible Data Files – Features
Below is a list of GPlates-compatible data files that can be loaded seamlessly in GPlates. The feature data are available as .gpml (GPlates Markup Language), .dat (PLATES4), .shp (ESRI Shapefile) and .xy (long, lat with header record) formats.

Data by the EarthByte Group are licensed under a Creative Commons Attribution 3.0 Unported License. When using GPlates and the sample data to make figures for publications, we recommend citing the original data sources as indicated below.

For users of GPlates 1.5, you can find the complete archived Sample Data from this link.

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Towards community-driven paleogeographic reconstructions: integrating open-access paleogeographic and paleobiology data with plate tectonics

PaleobioSummary
A variety of paleogeographic reconstructions have been published, with applications ranging from paleoclimate, ocean circulation and faunal radiation models to resource exploration; yet their uncertainties remain difficult to assess as they are generally presented as low-resolution static maps. We present a methodology for ground-truthing the digital Palaeogeographic Atlas of Australia by linking the GPlates plate reconstruction tool to the global Paleobiology Database and a Phanerozoic plate motion model.

We develop a spatio-temporal data mining workflow to validate the Phanerozoic Palaeogeographic Atlas of Australia with paleoenvironments derived from fossil data. … Read more…

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From data mining to opal mining

Opal NobbyDocuments
AJES Paper
CG Paper

Opal is Australia’s national gemstone, however most significant opal discoveries were made in the early 1900’s – more than 100 years ago – until recently. Currently there is no formal exploration model for opal, meaning there are no widely accepted concepts or methodologies available to suggest where new opal fields may be found. … Read more…

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Global continental and ocean basin reconstructions since 200 Ma

Plate reconstruction 200Ma-1Global plate motion models provide a spatial and temporal framework for geological data and have been effective tools for exploring processes occurring at the earth’s surface. However, published models either have insufficient temporal coverage or fail to treat tectonic plates in a self-consistent manner. They usually consider the motions of selected features attached to tectonic plates, such as continents, but generally do not explicitly account for the continuous evolution of plate boundaries through time. … Read more…

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Australian Paleo-stress map project

Fig12_0Ma-6Ma_asmUsing the engineering finite element modelling software package ABAQUS we have modelled the horizontal compressive stress of the Indo-Australian plate for time periods dating from the mid-Cretaceous. This work was carried out as part of the Tectonic Reactivation and Palaeo-Stress (TRAPS) Linkage project in collaboration with Shell, BHP Billiton,Woodside Petroleum and SANTOS in order to create a framework for predicting the tectonic reactivation of faults through time.

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Download dataset – zip file   … Read more…

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The IntraCONtinental basinS (ICONS) atlas

The ICONS atlas is a collection of basin data for over 240 intracontinental sedimentary basins, displaying crustal structure data, computed extension factors and tectonic subsidence grids and derivatives thereof as well as the dynamic topography evolution of a given basin. The atlas was compiled by Christian Heine as part of his PhD project investigating the formation and … Read more…

Testing absolute plate reference frames and the implications for the generation of geodynamic mantle heterogeneity structure

Shephard 2012 agegrids vels 140-1Absolute reference frames are a means of describing the motion of plates on the surface of the Earth over time, relative to a fixed point or frame. Multiple models of absolute plate motion have been proposed for the Cretaceous-Tertiary period, however, estimating the robustness and limitations of each model remains a significant limitation for refining both regional and global models of plate motion as well as fully integrated and time dependent geodynamic models. Here, we use a novel approach to compare five models of absolute plate motion in terms of their consequences for forward modelled deep mantle structure since at least 140 Ma. … Read more…

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Dynamic topography and anomalously negative residual depth of the Argentine Basin

Shephard 2012 Argentine Basin-1A substantial portion of Earth’s topography is known to be caused by the viscous coupling of mantle flow to the lithosphere but the relative contributions of shallow asthenospheric flow versus deeper flow remains controversial. The Argentine Basin, located offshore of the Atlantic margin of southern South America, is one of the most anomalously deep ocean regions as it is significantly deeper than its age would suggest. … Read more…

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Constraining the Jurassic extent of Greater India: Tectonic evolution of the West Australian margin

2011GC003919-p1a-1We present the Indian Ocean plate tectonic model accompanying the study of Gibbons et al., (2012). This work details the first regional-scale tectonic model of the breakup of East Gondwana. Our model shows that the breakup of East Gondwana started with the migration of a continental sliver, Argoland, in the Late Jurassic and was followed by breakup between Greater India and Australia-Antarctica in the Early Cretaceous, involving spreading reconfigurations, which left several sunken continental plateaus of Indian crust on the Australian plate. New evidence from seafloor off northwest Australia also shows that the majority of Greater India reached only about halfway up the West Australian margin, to the Wallaby-Zenith Plateaus. … Read more…

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An open-source software environment for visualizing and refining plate tectonic reconstructions using high-resolution geological and geophysical data sets

GSA Today Cover-1We describe a powerful method to explore spatio-temporal relationships within geological and geophysical data sets by analyzing the data within the context of tectonic reconstructions. GPlates is part of a new generation of plate reconstruction software that incorporates functionality familiar from GIS software with the added dimension of geological time. Here we use GPlates to reconstruct geological terranes, geophysical grids, and paleomagnetic data within alternative tectonic models of the assembly of Western Australia and the configuration of Rodinia. With the ability to rapidly visualize a diverse range of geological and geophysical constraints within different reconstructions, users can easily investigate the implications of different tectonic models for reconciling a variety of observations and make more informed choices between different models and data. … Read more…

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Insights on the kinematics of the India-Eurasia collision from global geodynamic models

Image 002We present the input plate motion models and results from the study by Zahirovic et al. (2012) on the India-Eurasia collision using linked kinematic and geodynamic models.

Two end-member scenarios of the India-Eurasia collision were tested. The conventional model invokes long-lived Andean-style subduction along southern Eurasia until continental collision between a maximum extent Greater India and Lhasa at ~60 Ma. … Read more…

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Full-fit, palinspastic reconstruction of the conjugate Australian-Antarctic margins

AusAntCThick47Ma-1Despite decades of study the pre-rift configuration and early rifting history between Australia and Antarctica is not well established. The plate boundary system during the Cretaceous includes the evolving Kerguelen-Broken Ridge Large Igneous Province in the west as well as the conjugate passive and transform margin segments of the Australian and Antarctic continents. … Read more…

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Dynamic subsidence of eastern Australia during the Cretaceous

Dynamic Subsidence of Eastern Australia Matthews et al (2011)During the Early Cretaceous Australia’s eastward passage over sinking subducted slabs induced widespread dynamic subsidence and formation of a large eperiogenic sea in the eastern interior. Despite evidence for convergence between Australia and the paleo-Pacific, the subduction zone location has been poorly constrained. Using coupled plate tectonic-mantle convection models, we test two end-member scenarios, one with subduction directly east of Australia’s reconstructed continental margin, and a second with subduction translated ~1000 km east, implying the existence of a back-arc basin. Our models incorporate a rheological model for the mantle and lithosphere, plate motions since 140 Ma and evolving plate boundaries. While mantle rheology affects the magnitude of surface vertical motions, timing of uplift and subsidence depends on plate boundary geometries and kinematics. … Read more…

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How supercontinents and superoceans affect seafloor roughness

Tasman Sea grav SW Indian grav Pacific grav

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, as well as on the local interaction of mid-ocean ridges with mantle plumes or cold-spots.
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