Although a significant volume of crust was extracted from the mantle early in Earth’s history, the contribution of felsic rocks to the sedimentary record was minimal until ~3.0 Ga. On a hotter Earth, this conundrum dissipates if we consider that the felsic crust was buried under thick basaltic covers, continents were flooded by a near-global … Read more…
We evaluate four mantle convection models that use tectonic reconstructions to specify kinematic boundary conditions to explore the development of the lower mantle large low shear velocity provinces (LLSVP) structures and their relationship with mantle plumes. Evolution of mantle plumes in our spherical models is broadly consistent with observations including the number of plumes generated … Read more…
Our capability to reconstruct past landscapes and the processes that shape them underpins our understanding of paleo-Earth. We take advantage of a global-scale landscape evolution model assimilating paleoelevation and paleoclimate reconstructions over the past 100 million years. This model provides continuous quantifications of metrics critical to the understanding of the Earth system, from global physiography … Read more…
In the context of continental extension, transient compressional episodes (stress inversion) and phases of uplift (depth inversion) are commonly recorded with no corresponding change in plate motion. Changes in gravitational potential energy during the rifting process have been invoked as a possible source of compressional stresses, but their magnitude, timing, and relationship with depth inversions … Read more…
Dynamic subsidence and uplift of plates are often explained by the vertical motion of density anomalies in the mantle. Such models predict surface vertical motion rates of less than 100 m Myr−1 at long-wavelengths with a timespan of tens of Myr. However, during periods of relative sea-level stability, some of the phases of vertical motion … Read more…
The Tibetan Plateau plays a central role in global atmospheric circulation, acts as a key biodiversity hotspot, and delivers fresh water for more than 20% of the global population. Projecting its future uplift and erosion trajectory over geological time can offer potential testable hypotheses into interactions between tectonic and surface processes. Rey, P., Salles, T., … Read more…
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…
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…
How can the sluggish, long-wavelength mantle convection be expressed by so many time and space scales of morphotectonic activity? To investigate these relationships, we explore the Java-Banda subduction zone, where geodynamic records cluster. In the far-East Tethys, the exceptionally arcuate Banda subduction zone circumscribes the deepest oceanic basin on Earth, seismotectonic activity slices the upper … Read more…
A drastic change in plate tectonics and mantle convection occurred around 50 Ma as exemplified by the prominent Hawaiian– Emperor Bend. Both an abrupt Pacific Plate motion change and a change in mantle plume dynamics have been proposed to account for the Hawaiian–Emperor Bend, but debates surround the relative contribution of the two mechanisms. Here … Read more…
Seismic studies have revealed two Large Low-Shear Velocity Provinces (LLSVPs) in the lowermost mantle. Whether these structures remain stable over time or evolve through supercontinent cycles is debated. Here we analyze a recently published mantle flow model constrained by a synthetic plate motion model extending back to one billion years ago, to investigate how the … Read more…
Significance We report the discovery of anomalously high 3He/4He in “cold” geothermal fluids of central Panama, far from any active volcanoes. Combined with independent constraints from lava geochemistry, mantle source geochemical anomalies in Central America require a Galapagos plume contribution that is not derived from hotspot track recycling. Instead, these signals likely originate from large-scale … Read more…
Widespread flooding of the Australian continent during the Early Cretaceous, referred to as the Eromanga Sea, deposited extensive shallow marine sediments throughout the Great Artesian Basin (GAB). This event had been considered ‘out of sync’ with eustatic sea level and was instead solely attributed to dynamic subsidence associated with Australia’s passage over eastern Gondwanan subducted … Read more…
Ben Mather won the People’s Choice Award at the recent #AuScope2021 Conference for his fantastic presentation explaining the evolution of seafloor volcanoes off the eastern Australian coast. Watch it here.
The existence of mantle plumes was first proposed in the 1970s to explain intra-plate, hotspot volcanism, yet owing to difficulties in resolving mantle upwellings with geophysical images and discrepancies in interpretations of geochemical and geochronological data, the origin, dynamics and composition of plumes and their links to plate tectonics are still contested. In a recently … Read more…