8 July, 2009 (16:00 GMT), 5 Merrion Square, Dublin 2.
Speaker: Kim Welford (Memorial University of Newfoundland in St. John’s, Canada).
Title: Lithospheric density variations and Moho structure of the Irish rifted continental margin from constrained 3 D gravity inversion.
Abstract:
The structurally complex Irish margin was separated from its conjugate pair, the northern Flemish Cap/Orphan Basin region, during Late Cretaceous rifting of the North Atlantic. While crustal-scale 2-D seismic surveys have been collected across many parts of the margin, the results generated from these surveys cannot easily be interpreted in a regional sense due to their sparse sampling. We have undertaken a 3-D gravity inversion of the free air data over the Irish margin in order to generate a 3-D density anomaly model that can be compared with the seismic results and used to gain insight into regions lacking seismic coverage. We use the GRAV3D inversion algorithm and constrain our inverted model with bathymetric and sediment thickness information. We are able to closely reproduce the observed gravity anomalies over the margin and use the resultant density anomaly model to interpret the regional Moho structure by identifying a density isosurface appropriate for the crust-mantle
transition. Our interpreted Moho shows good correspondence with Moho depths from seismic results while providing a more detailed Moho depth map over the region. This map allows the lateral extent of crustal thinning beneath the Rockall Trough, the Porcupine Seabight Basin and south of Goban Spur to be investigated. We present regional cross-sections through the 3-D model to highlight lateral variations in Moho structure and lithospheric densities. We also map thickness variations in upper, middle and lower crustal densities across the margin. These maps may be revealing zones of exhumed serpentinized mantle in the Porcupine Basin, the Rockall Basin and outboard of Goban Spur and the Porcupine High. Anomalous zones of high density in the lower crust off the southern margin the Celtic Platform into the Biscay Abyssal Plain may provide evidence for underplating. Ultimately, the insights provided by our results must act as constraints for future paleoreconstructions of North Atlantic rifting.
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Last Updated: 22nd March 2016 by Anna
2009-07-08 – SEMINAR by Kim Welford: Lithospheric density variations and Moho structure of the Irish rifted continental margin from constrained 3 D gravity inversion
8 July, 2009 (16:00 GMT), 5 Merrion Square, Dublin 2.
Speaker: Kim Welford (Memorial University of Newfoundland in St. John’s, Canada).
Title: Lithospheric density variations and Moho structure of the Irish rifted continental margin from constrained 3 D gravity inversion.
Abstract:
The structurally complex Irish margin was separated from its conjugate pair, the northern Flemish Cap/Orphan Basin region, during Late Cretaceous rifting of the North Atlantic. While crustal-scale 2-D seismic surveys have been collected across many parts of the margin, the results generated from these surveys cannot easily be interpreted in a regional sense due to their sparse sampling. We have undertaken a 3-D gravity inversion of the free air data over the Irish margin in order to generate a 3-D density anomaly model that can be compared with the seismic results and used to gain insight into regions lacking seismic coverage. We use the GRAV3D inversion algorithm and constrain our inverted model with bathymetric and sediment thickness information. We are able to closely reproduce the observed gravity anomalies over the margin and use the resultant density anomaly model to interpret the regional Moho structure by identifying a density isosurface appropriate for the crust-mantle
transition. Our interpreted Moho shows good correspondence with Moho depths from seismic results while providing a more detailed Moho depth map over the region. This map allows the lateral extent of crustal thinning beneath the Rockall Trough, the Porcupine Seabight Basin and south of Goban Spur to be investigated. We present regional cross-sections through the 3-D model to highlight lateral variations in Moho structure and lithospheric densities. We also map thickness variations in upper, middle and lower crustal densities across the margin. These maps may be revealing zones of exhumed serpentinized mantle in the Porcupine Basin, the Rockall Basin and outboard of Goban Spur and the Porcupine High. Anomalous zones of high density in the lower crust off the southern margin the Celtic Platform into the Biscay Abyssal Plain may provide evidence for underplating. Ultimately, the insights provided by our results must act as constraints for future paleoreconstructions of North Atlantic rifting.
Category: Geophysics Section News & Events
Big thank you to @MartinaPQuinn of @helloalicepr for moderating the discussion, and of course to our panel @NeasaMcG @CormacORafferty and @laoneill111
@CormacORafferty "to cut yourself off from fundamental research means you could miss out on some of the biggest ideas"
@laoneill "it's our job as researchers to keep reminding governments how important basic research is" "For Dev basic research being carried out in Ireland was a badge of pride"
@NeasaMcG Schrödinger's work in causality was not well received by the religious authorities at the time At the same time DIAS did have Catholic priests working on research projects in the early days, so there was not the conflict you might think between science and religion
@laoneill111 Schrödinger was very popular in social circles in Dublin, a bit of a renaissance man
@CormacORafferty Schrödinger was gifted at explaining difficult concepts
@CormacORafferty on how unsuccessful work, in Schrödinger's case, unified field theory, is just as important part of science. And no one has managed to crack it yet! And not forgetting the cat
@laoneill111 how Schrödinger's book inspired scientists to change fields and result in the finding of the double helix.
@NeasaMcG explaining how DIAS came about and how Schrödinger was attracted to Ireland #DIASdiscovers
Panel Discussion getting underway! @laoneill111 @CormacORafferty @NeasaMcG @MartinaPQuinn
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Starting in just over an hour we have limited tickets left for tonights broadcast and panel discussion. Get your free ticket now twitter.com/DIAS_Dublin/st…
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@dias_geophysics have developed something special for @galway2020 in collaboration with composer David Stalling. It is an audio-visual composition “Palace of Ships,” based on sounds, images and seismic data from DIAS’ @SEA_SEIS Expeditions. More: dias.ie/2020/09/14/dia…
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