Uncertainties in break-up markers along the Iberia–Newfoundland margins illustrated by new seismic data
Plate tectonic modellers often rely on the identification of “break-up” markers to reconstruct the early stages of continental separation. Along the Iberian-Newfoundland margin, so-called break-up markers include interpretations of old magnetic anomalies from the M series, as well as the “J anomaly”...
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ftcopernicus:oai:publications.copernicus.org:se80138 2023-05-15T17:19:01+02:00 Uncertainties in break-up markers along the Iberia–Newfoundland margins illustrated by new seismic data Causer, Annabel Pérez-Díaz, Lucía Adam, Jürgen Eagles, Graeme 2020-03-30 application/pdf https://doi.org/10.5194/se-11-397-2020 https://se.copernicus.org/articles/11/397/2020/ eng eng doi:10.5194/se-11-397-2020 https://se.copernicus.org/articles/11/397/2020/ eISSN: 1869-9529 Text 2020 ftcopernicus https://doi.org/10.5194/se-11-397-2020 2020-07-20T16:22:20Z Plate tectonic modellers often rely on the identification of “break-up” markers to reconstruct the early stages of continental separation. Along the Iberian-Newfoundland margin, so-called break-up markers include interpretations of old magnetic anomalies from the M series, as well as the “J anomaly”. These have been used as the basis for plate tectonic reconstructions are based on the concept that these anomalies pinpoint the location of first oceanic lithosphere. However, uncertainties in the location and interpretation of break-up markers, as well as the difficulty in dating them precisely, has led to plate models that differ in both the timing and relative palaeo-positions of Iberia and Newfoundland during separation. We use newly available seismic data from the Southern Newfoundland Basin (SNB) to assess the suitability of commonly used break-up markers along the Newfoundland margin for plate kinematic reconstructions. Our data show that basement associated with the younger M-series magnetic anomalies is comprised of exhumed mantle and magmatic additions and most likely represents transitional domains and not true oceanic lithosphere. Because rifting propagated northward, we argue that M-series anomaly identifications further north, although in a region not imaged by our seismic, are also unlikely to be diagnostic of true oceanic crust beneath the SNB. Similarly, our data also allow us to show that the high amplitude of the J Anomaly is associated with a zone of exhumed mantle punctuated by significant volcanic additions and at times characterized by interbedded volcanics and sediments. Magmatic activity in the SNB at a time coinciding with M4 (128 Ma) and the presence of SDR packages onlapping onto a basement fault suggest that, at this time, plate divergence was still being accommodated by tectonic faulting. We illustrate the differences in the relative positions of Iberia and Newfoundland across published plate reconstructions and discuss how these are a direct consequence of the uncertainties introduced into the modelling procedure by the use of extended continental margin data (dubious magnetic anomaly identifications, break-up unconformity interpretations). We conclude that a different approach is needed for constraining plate kinematics of the Iberian plate pre-M0 times. Text Newfoundland Copernicus Publications: E-Journals Solid Earth 11 2 397 417 |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Plate tectonic modellers often rely on the identification of “break-up” markers to reconstruct the early stages of continental separation. Along the Iberian-Newfoundland margin, so-called break-up markers include interpretations of old magnetic anomalies from the M series, as well as the “J anomaly”. These have been used as the basis for plate tectonic reconstructions are based on the concept that these anomalies pinpoint the location of first oceanic lithosphere. However, uncertainties in the location and interpretation of break-up markers, as well as the difficulty in dating them precisely, has led to plate models that differ in both the timing and relative palaeo-positions of Iberia and Newfoundland during separation. We use newly available seismic data from the Southern Newfoundland Basin (SNB) to assess the suitability of commonly used break-up markers along the Newfoundland margin for plate kinematic reconstructions. Our data show that basement associated with the younger M-series magnetic anomalies is comprised of exhumed mantle and magmatic additions and most likely represents transitional domains and not true oceanic lithosphere. Because rifting propagated northward, we argue that M-series anomaly identifications further north, although in a region not imaged by our seismic, are also unlikely to be diagnostic of true oceanic crust beneath the SNB. Similarly, our data also allow us to show that the high amplitude of the J Anomaly is associated with a zone of exhumed mantle punctuated by significant volcanic additions and at times characterized by interbedded volcanics and sediments. Magmatic activity in the SNB at a time coinciding with M4 (128 Ma) and the presence of SDR packages onlapping onto a basement fault suggest that, at this time, plate divergence was still being accommodated by tectonic faulting. We illustrate the differences in the relative positions of Iberia and Newfoundland across published plate reconstructions and discuss how these are a direct consequence of the uncertainties introduced into the modelling procedure by the use of extended continental margin data (dubious magnetic anomaly identifications, break-up unconformity interpretations). We conclude that a different approach is needed for constraining plate kinematics of the Iberian plate pre-M0 times. |
format |
Text |
author |
Causer, Annabel Pérez-Díaz, Lucía Adam, Jürgen Eagles, Graeme |
spellingShingle |
Causer, Annabel Pérez-Díaz, Lucía Adam, Jürgen Eagles, Graeme Uncertainties in break-up markers along the Iberia–Newfoundland margins illustrated by new seismic data |
author_facet |
Causer, Annabel Pérez-Díaz, Lucía Adam, Jürgen Eagles, Graeme |
author_sort |
Causer, Annabel |
title |
Uncertainties in break-up markers along the Iberia–Newfoundland margins illustrated by new seismic data |
title_short |
Uncertainties in break-up markers along the Iberia–Newfoundland margins illustrated by new seismic data |
title_full |
Uncertainties in break-up markers along the Iberia–Newfoundland margins illustrated by new seismic data |
title_fullStr |
Uncertainties in break-up markers along the Iberia–Newfoundland margins illustrated by new seismic data |
title_full_unstemmed |
Uncertainties in break-up markers along the Iberia–Newfoundland margins illustrated by new seismic data |
title_sort |
uncertainties in break-up markers along the iberia–newfoundland margins illustrated by new seismic data |
publishDate |
2020 |
url |
https://doi.org/10.5194/se-11-397-2020 https://se.copernicus.org/articles/11/397/2020/ |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_source |
eISSN: 1869-9529 |
op_relation |
doi:10.5194/se-11-397-2020 https://se.copernicus.org/articles/11/397/2020/ |
op_doi |
https://doi.org/10.5194/se-11-397-2020 |
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Solid Earth |
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397 |
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417 |
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