Examining the influence of tectonic inheritance on the evolution of the North Atlantic using a palinspastic deformable plate reconstruction

2018 ◽  
Vol 470 (1) ◽  
pp. 245-264 ◽  
Author(s):  
Bridget E. Ady ◽  
Richard C. Whittaker
Keyword(s):  
North Atlantic ◽  
Kinematic Model ◽  
Spatial Relationship ◽  
Structural Features ◽  
Plate Model ◽  
Tectonic Inheritance ◽  
The North ◽  
Rifted Margins ◽  
Plate Reconstruction ◽  
Conjugate Margins

AbstractTo accurately reconstruct plate configurations, there is a need for a quantitative method to calculate the amount and timing of crustal extension independent of any one model for the formation of rifted margins. This paper evaluates the suitability of the various plate modelling methods for structural inheritance studies and proposes a classification scheme for the methods that are currently in use. A palinspastic deformable margin plate kinematic model is most suitable for tectonic inheritance studies, particularly at hyperextended margins. This type of plate model provides a valuable analytical tool that can be used to show the temporal and spatial relationship between pre-existing orogenic structures, evolving rift axes and global plate reorganization events. We use a palinspastic deformable margin plate model for the southern North Atlantic and Labrador Sea to quantitatively restore up to 350 km of Mesozoic–Cenozoic extension. This provides us with a pre-rift restoration of the Proterozoic and Paleozoic terranes and structural lineaments on the conjugate margins that helps us to analyse their relationship to evolving rift axes and global plate reorganization events through time. Interpretation of these modelling results has led to a clearer understanding of the relationship between inherited structural features and their control on rifting and the break-up history.

The importance of Iberia for the restoration of the Mesozoic Alpine Tethys

2021 ◽  
Author(s):  
Gianluca Frasca ◽  
Gianreto Manatschal ◽  
Patricia Cadenas ◽  
Jordi Mirò ◽  
Rodolphe Lescoutre
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Kinematic Model ◽  
Direct Access ◽  
Published Data ◽  
The North ◽  
Rifted Margins ◽  
Key Points ◽  
Western Side ◽  
The Impact

<p>Fossil remnants of rifted margins sampled in orogens enable to unravel the nature of rocks, structures and conditions controlling the formation of rifted margins and lithosphere breakup. However, a major problem in orogens is that disconnected remnants of only one margin are preserved, while the conjugate has often been subducted and/or obliterated during convergence. Thus, our understanding of rift processes leading to lithosphere breakup is hampered by the impossibility to direct access to well-preserved examples of conjugate rifted margins fossilised onshore. Here we focus our attention on the Mesozoic Alpine Tethys, bounded by the European and African plates and interleaving crustal blocks such Iberia and Adria. Two key points have to be resolved in order to reconstruct conjugate distal margins in the Alpine Tethys paleogeographic setting. First, a restoration of the European western side of the Alpine Tethys has to be performed. Second, the position of Iberia during the Mesozoic has to be restored taking into account the evolution and opening of the southern North Atlantic and the Bay of Biscay. Here we propose a new Mesozoic kinematic model for Iberia, which is compatible at a first order and large scale with recently published data and interpretations from the North Iberian margin and the Pyrenean domain. We discuss the impact of the results for the reconstruction of the Alpine Tethys.</p>

scholarly journals Two deep-mantle sources for Paleocene doming and volcanism in the North Atlantic

2019 ◽  
Vol 116 (27) ◽  
pp. 13227-13232 ◽  
Author(s):  
Petar Glišović ◽  
Alessandro M. Forte
Keyword(s):  
North Atlantic ◽  
Lower Mantle ◽  
North Atlantic Ocean ◽  
Small Scale ◽  
The North ◽  
Rifted Margins ◽  
Mantle Sources ◽  
Cenozoic Era ◽  
The North Atlantic ◽  
North Atlantic Igneous Province

The North Atlantic Igneous Province (NAIP) erupted in two major pulses that coincide with the continental breakup and the opening of the North Atlantic Ocean over a period from 62 to 54 Ma. The unknown mantle structure under the North Atlantic during the Paleocene represents a major missing link in deciphering the geodynamic causes of this event. To address this outstanding challenge, we use a back-and-forth iterative method for time-reversed global convection modeling over the Cenozoic Era which incorporates models of present-day tomography-based mantle heterogeneity. We find that the Paleocene mantle under the North Atlantic is characterized by two major low-density plumes in the lower mantle: one beneath Greenland and another beneath the Azores. These strong lower-mantle upwellings generate small-scale hot upwellings and cold downwellings in the upper mantle. The upwellings are dispersed sources of magmatism and topographic uplift that were active on the rifted margins of the North Atlantic during the formation of the NAIP. While most studies of the Paleocene evolution of the North Atlantic have focused on the proto-Icelandic plume, our Cenozoic reconstructions reveal the equally important dynamics of a hot, buoyant, mantle-wide upwelling below the Azores.

scholarly journals A reconstruction of Iberia accounting for Western Tethys–North Atlantic kinematics since the late-Permian–Triassic

Solid Earth ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 1313-1332 ◽  
Author(s):  
Paul Angrand ◽  
Frédéric Mouthereau ◽  
Emmanuel Masini ◽  
Riccardo Asti
Keyword(s):  
North Atlantic ◽  
Kinematic Model ◽  
Plate Boundary ◽  
Strike Slip ◽  
Late Permian ◽  
Geological Evidence ◽  
Western Tethys ◽  
The North ◽  
Kinematic Evolution ◽  
Strike Slip Movement

Abstract. The western European kinematic evolution results from the opening of the western Neotethys and the Atlantic oceans since the late Paleozoic and the Mesozoic. Geological evidence shows that the Iberian domain recorded the propagation of these two oceanic systems well and is therefore a key to significantly advancing our understanding of the regional plate reconstructions. The late-Permian–Triassic Iberian rift basins have accommodated extension, but this tectonic stage is often neglected in most plate kinematic models, leading to the overestimation of the movements between Iberia and Europe during the subsequent Mesozoic (Early Cretaceous) rift phase. By compiling existing seismic profiles and geological constraints along the North Atlantic margins, including well data over Iberia, as well as recently published kinematic and paleogeographic reconstructions, we propose a coherent kinematic model of Iberia that accounts for both the Neotethyan and Atlantic evolutions. Our model shows that the Europe–Iberia plate boundary was a domain of distributed and oblique extension made of two rift systems in the Pyrenees and in the Iberian intra-continental basins. It differs from standard models that consider left-lateral strike-slip movement localized only in the northern Pyrenees in introducing a significant strike-slip movement south of the Ebro block. At a larger scale it emphasizes the role played by the late-Permian–Triassic rift and magmatism, as well as strike-slip faulting in the evolution of the western Neotethys Ocean and their control on the development of the Atlantic rift.

Assessing the rotation and segmentation of the Porcupine Bank, Irish Atlantic margin, during oblique rifting using deformable plate reconstruction

2021 ◽  
Author(s):  
Pei Yang ◽  
J. Kim Welford ◽  
Michael King
Keyword(s):  
North Atlantic ◽  
Seismic Refraction ◽  
Gravity Inversion ◽  
Geological Time ◽  
Potential Field Data ◽  
The North ◽  
Porcupine Basin ◽  
Four Blocks ◽  
Seismic Refraction Data ◽  
Plate Reconstruction

<p>With an increasing number of global and regional plate reconstruction models established in recent years, the motion of the Porcupine Bank, Irish Atlantic continental margin, underlain by orogeny-related pre-rift crustal basement terranes, have been investigated and restored as well.  However, these reconstructed models of the Porcupine Bank margin mainly depend on potential field data analysis and lack seismic constraints, failing to reveal the role of inherited crustal sutures during rifting and associated crustal deformation over geological time. In this study, five deformable models with distinct structural inheritance trends are established in GPlates by adjusting a previously published regional restoration model for the North Atlantic realm. For each model, driving factors (e.g., such as whether the Orphan Knoll is included, the altered rotational poles of the Flemish Cap, and the motion of the eastern border of the Porcupine Basin) are also taken into consideration. Crustal thicknesses from gravity inversion and seismic refraction data modelling are compared against those from these deformable plate reconstruction models to identify the most geologically reasonable one. The resulting preferred model has the Porcupine Bank subdivided into four blocks with each experiencing polyphase rotations and shearing prior to final continental breakup, implying strong inheritance and segmentation of the Porcupine Bank and the Porcupine Basin. The derived reconstructed paleo-positions over time of the Flemish Cap and the Porcupine Bank within the deforming topological network reveal new and evolving conjugate relationships during rifting, which are assessed using regional seismic transects from both margins. Finally, extensional obliquity between both margins is quantitatively restored, showing time-variant orientations due to the rotation and shearing of associated continental blocks, which contributes to unraveling the spatial and temporal evolution of southern North Atlantic rifting during the Mesozoic, prior to the initiation of seafloor spreading.</p>

scholarly journals The Tertiary opening of the North Atlantic: DLC investigations along the east coast of Greenland

1995 ◽  
Vol 165 ◽  
pp. 106-115
Author(s):  
H.C Larsen ◽  
C.K Brooks ◽  
J.R Hopper ◽  
T Dahl-Jensen ◽  
A.K Pedersen ◽  
...  
Keyword(s):  
North Atlantic ◽  
Time Scale ◽  
Tectonic Evolution ◽  
East Coast ◽  
Thermal State ◽  
The North ◽  
Rifted Margins ◽  
The North Atlantic ◽  
Break Up

Work along the east coast of Greenland in the summer of 1994 represents the initiation of the Danish Lithosphere Centre (DLC) investigations into the magmatic and tectonic evolution accompanying initial break-up of the North Atlantic in this area. As described by Larsen (this report), the aims of DLC are the understanding of the composition and thermal state of the asthenosphere and the deformation of the lithosphere during continental break-up and formation of volcanic rifted margins. Furthermore, the time scale of these events is crucial to any model of break-up.

The Politics of Collective Inaction: NATO's Response to the Prague Spring

1999 ◽  
Vol 1 (3) ◽  
pp. 111-138 ◽  
Author(s):  
John G. McGinn
Keyword(s):  
North Atlantic ◽  
North Atlantic Treaty Organization ◽  
Structural Features ◽  
Military Action ◽  
The North ◽  
Prague Spring ◽  
The North Atlantic

The North Atlantic Treaty Organization (NATO) kept close track of developments in Czechoslovakia throughout 1968, but the alliance did not pursue a coherent policy toward the uprising. A close examination of NATO actions from January 1968 until the invasion on 20–21 August helps explain why a coordinated approach never materialized. Certain structural features of the alliance and a host of domestic and external distractions precluded a joint response. NATO members worked individually rather than collectively to avert Soviet military action through quiet diplomacy, but these efforts made almost no difference.

scholarly journals Trace element and isotope constraints on crustal anatexis by upwelling mantle melts in the North Atlantic Igneous Province: an example from the Isle of Rum, NW Scotland

2009 ◽  
Vol 146 (3) ◽  
pp. 382-399 ◽  
Author(s):  
ROMAIN MEYER ◽  
GRAEME R. NICOLL ◽  
JAN HERTOGEN ◽  
VALENTIN R. TROLL ◽  
ROBERT M. ELLAM ◽  
...  
Keyword(s):  
Trace Element ◽  
North Atlantic ◽  
Trace Element Content ◽  
Crustal Anatexis ◽  
The North ◽  
Rock Types ◽  
Rifted Margins ◽  
Igneous Province ◽  
The North Atlantic ◽  
North Atlantic Igneous Province

AbstractSr and Nd isotope ratios, together with lithophile trace elements, have been measured in a representative set of igneous rocks and Lewisian gneisses from the Isle of Rum in order to unravel the petrogenesis of the felsic rocks that erupted in the early stages of Palaeogene magmatism in the North Atlantic Igneous Province (NAIP). The Rum rhyodacites appear to be the products of large amounts of melting of Lewisian amphibolite gneiss. The Sr and Nd isotopic composition of the magmas can be explained without invoking an additional granulitic crustal component. Concentrations of the trace element Cs in the rhyodacites strongly suggests that the gneiss parent rock had experienced Cs and Rb loss prior to Palaeogene times, possibly during a Caledonian event. This depletion caused heterogeneity with respect to87Sr/86Sr in the crustal source of silicic melts. Other igneous rock types on Rum (dacites, early gabbros) are mixtures of crustal melts and and primary mantle melts. Forward Rare Earth Element modelling shows that late stage picritic melts on Rum are close analogues for the parent melts of the Rum Layered Suite, and for the mantle melts that caused crustal anatexis of the Lewisian gneiss. These primary mantle melts have close affinities to Mid-Oceanic Ridge Basalts (MORB), whose trace element content varies from slightly depleted to slightly enriched. Crustal anatexis is a common process in the rift-to-drift evolution during continental break-up and the formation of Volcanic Rifted Margins systems. The ‘early felsic–later mafic’ volcanic rock associations from Rum are compared to similar associations recovered from the now-drowned seaward-dipping wedges on the shelf of SE Greenland and on the Vøring Plateau (Norwegian Sea). These three regions show geochemical differences that result from variations in the regional crustal composition and the depth at which crustal anatexis took place.

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