Assessing discrepancies between previous plate kinematic models of Mesozoic Iberia and their constraints

Abstract

Currently, there are several published end-member plate models that describe the evolution of Iberia during the Mesozoic. We review key geological and geophysical data sets previously used as constraints on these models including (1) geological interpretations of Pyrenean geology; (2) end-member interpretations of magnetic anomalies along the West Iberian and Newfoundland margins and Bay of Biscay;(3) the paleomagnetic data set of Iberia; and (4) seismic tomography models, which have previously been used to support Cretaceous subduction between Iberia and Eurasia. From this review we identify key constraints and argue that a reasonable plate kinematic model of Iberia should satisfy all of these. Instead, we determine inconsistencies between these key constraints and several published end-member plate models through a kinematic analysis using the GPlates software. We also analyze published seismic tomography models, not previously considered, across northern Africa and Iberia, and identify no slab preserved within the mantle supposedly linked to Cretaceous subduction between Iberia and Eurasia. A lack of published geological evidence along the Pyrenees supporting this subduction history also casts doubt on this scenario. Our kinematic analysis highlights that, first, the cessation in transtensional motion between Iberia and Eurasia by the Albian cannot be kinematically reconciled with the concurrent breakup between Iberia and Newfoundland in the Atlantic when reconstructing existing continent-ocean boundary interpretations along their respective margins. Second, either fit of the contentious end-member M 0 interpretations (~120.6 Ma) between Iberia and Newfoundland implies plate velocities of Iberia that results in its undocumented transpressional or compressional motion relative to Eurasia until C 34 .

A New Southern North Atlantic Isochron Map: Insights Into the Drift of the Iberian Plate Since the Late Cretaceous

“…The kinematics of Iberia during the first phase have been the subject of recent debate (Barnett-Moore et al, 2016;Bronner et al, 2011;Eddy et al, 2017;Nirrengarten et al, 2017;Norton et al, 2007;Péron-Pinvidic & Manatschal, 2009;Tucholke et al, 2007). Currently, three competing kinematic models have been proposed for the time interval from the Jurassic to the Cretaceous (154-83.5 Ma).…”

Crustal structure and evolution of the Pyrenean-Cantabrian belt: A review and new interpretations from recent concepts and data

“…oceanic magnetic anomalies, rotation poles). In addition to the uncertainties in the early Cretaceous history arising from the diverse interpretation of the J-anomalies in the North Atlantic (chrons M0 to M4; Sibuet , 2004;Bronner et al, 2011;Nirrengarten et al, 2017), the reconstructed separation between the Iberian and Eurasian plates in the late Cretaceous, previous to the widely accepted onset of the Pyrenean orogeny at ~84 Ma, range from 200 km in the east of the Pyrenees and 100 km in the west (Roest and Srivastava, 1991) to 180 km or 150-140 km in the central Pyrenees (Olivet, 1996;Barnett-Moore et al, 2016). To this discrepancy we can affix the purported separation of 400 km consumed by scissor-like convergence since the early Cretaceous envisaged by Sibuet et al (2004) and Vissers and Meijer (2011), discussed above.…”

Reply to Comment by Pedreira et al. on “Reconstruction of the Exhumed Mantle Across the North Iberian Margin by Crustal‐Scale 3‐D Gravity Inversion and Geological Cross Section”

“…Pedreira et al () indicate that the shortening estimate in the Gernika section is considerably lower than the one predicted by some plate kinematic models (Macchiavelli et al, ; Rosenbaum et al, ; Vissers & Meijer, ). However, contradictory kinematic models have been proposed to explain the evolution of Iberia with dissimilar timing, direction, and amount of convergence (Barnett‐Moore et al, ). Among other difficulties, plate kinematic reconstructions are hampered by large strike‐slip movements of Iberia that are not registered by the architecture of sedimentary basins.…”