85 research outputs found
TectonoâStratigraphic Evolution of the Kerguelen Large Igneous Province: The Conjugate Williamâs RidgeâBroken Ridge Rifted Margins
AbstractExtensive investigation of continental rift systems has been fundamental for advancing the understanding of extensional tectonics and modes of formation of new ocean basins. However, current rift classification schemes do not account for conjugate end members formed by Large Igneous Province crust, referring to thick mafic crust, sometimes including continental fragments. Here, we investigate the rifting of William's Ridge (Kerguelen Plateau) and Broken Ridge, components of the Kerguelen Large Igneous Province now situated in the Southeast Indian Ocean, and incorporate these end members into the deformation migration concept for rifted margins. We use multichannel seismic reflection profiles and data from scientific drill cores acquired on both conjugate margins to propose, for the first time, a combined tectonoâstratigraphic framework. We interpret seismic patterns, tectonic features, and magnetic anomaly picks to determine an acrossâstrike structural domain classification. This interpretation considers the rift system overall to be âmagmaâpoorâ despite being located proximal to the Kerguelen plume but suggests that synârift interaction between the Kerguelen mantle plume and the lithospheric structure of William's Ridge and Broken Ridge has controlled the alongâstrike segmentation of both conjugates. We integrate seismic reflection and bathymetric data to test the hypothesis of predominantly transform motion, between the Australian and Antarctic plates, in Late Cretaceous and Paleogene time.</jats:p
A transdisciplinary and community-driven database to unravel subduction zone initiation
Subduction zones are pivotal for the recycling of Earthâs outer layer into its interior. However, the conditions under which new subduction zones initiate are enigmatic. Here, we constructed a transdisciplinary database featuring detailed analysis of more than a dozen documented subduction zone initiation events from the last hundred million years. Our initial findings reveal that horizontally forced subduction zone initiation is dominant over the last 100âMa, and that most initiation events are proximal to pre-existing subduction zones. The SZI Database is expandable to facilitate access to the most current understanding of subduction zone initiation as research progresses, providing a community platform that establishes a common language to sharpen discussion across the Earth Science community
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