ORCID Profile
0000-0002-5919-5303
Current Organisation
Memorial University of Newfoundland
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Publisher: Copernicus GmbH
Date: 15-05-2023
DOI: 10.5194/EGUSPHERE-EGU23-7211
Abstract: There is a long-standing mystery regarding how subduction zones enter internal Atlantic-type oceans to complete their Wilson cycle. While the process of subduction initiation is challenging to tackle, the Atlantic is a natural laboratory that allows understanding of some of the different stages of the process of invasion of new subduction zones. Three different subduction zones seem to be entering the Atlantic from different edges: the Caribbean Arc, the Scotia Arc and around the Iberia Peninsula. While the first two ex les constitute fully developed subduction zones, it is unknown how they will propagate in the future. Will they spread intra-oceanically or will the subduction migrate along the Atlantic passive margins? Iberia is a good place to investigate the processes involved in the formation of new subduction zones. There have been places of aborted subduction (along the Cantabrian margin), places of incipient subduction (North, West and Southwest Iberia) and there is a subduction arc currently propagating into the Atlantic Ocean (the Gibraltar Arc). We will focus on this last case. Last year, we presented a numerical model that showed that the Gibraltar Arc may indeed further propagate into the Atlantic. This year, we present new models that investigate the factors controlling such propagation. We test different parameters such as the presence of weak zones in the adjacent margins and in the oceanic lithosphere (fracture zones) to obtain insights into the main factors controlling the first stages of propagation of new subduction zones in Atlantic-type oceans.& This work was funded by the Portuguese Funda& #231 & #227 o para a Ci& #234 ncia e a Tecnologia (FCT) I.P./MCTES through national funds (PIDDAC) & #8211 UIDB/50019/2020- IDL
Publisher: Copernicus GmbH
Date: 15-05-2023
DOI: 10.5194/EGUSPHERE-EGU23-6654
Abstract: The structure of Iberian Atlantic margins resulted from multiple Mesozoic rift events and subsequent contractional deformation occurring from the Upper Cretaceous to Cenozoic during the Alpine Orogeny. Along the southern Bay of Biscay, the North Iberian margin shows various styles of contractional deformation, ranging from mild reactivation of pre-existing extensional structures, halokynetic-related processes, to wedging and underthrusting. The Biscay accretionary wedge developed as the major structure at the base of the continental slope in the central and western parts of the North Iberian margin, which are part of the western branch of the Pyrenean-Cantabrian Orogen, together with the Cantabrian Mountains onshore. The wedge is interpreted to continue from the western North Iberian margin, where incipient subduction has been proposed, to the Galicia Margin further to the southwest. Along the West Iberian margin, thrusting and related folding and halokynetic-related processes focused contractional deformation.In this work, we describe the seismo-stratigraphy, and we map contractional structures along the North Iberian and West Iberian margins based on the interpretation of 2D seismic reflection profiles. We identify and describe structural domains along the extinct subduction zone along the North Iberian margin, describe the structure of the fossil Biscay accretionary wedge, and identify and map different styles of Alpine contractional deformation along the North Iberian and West Iberian margins. We also describe the pre-existing Mesozoic rift structure in order to analyse the overprint between different rift architectures and contractional styles of deformation. The overall goal is to define different styles and stages of Alpine contractional deformation along Iberian Atlantic margins during the first phases of the convergent cycle preceding or leading to subduction.&
Publisher: Elsevier BV
Date: 07-2020
Location: Canada
Location: No location found
No related grants have been discovered for J Kim Welford.