Cretaceous‐Paleocene Evolution and Crustal Structure of the Northern Vøring Margin (Offshore Mid‐Norway): Results from Integrated Geological and Geophysical Study

Zastrozhnov, Dmitry; Gernigon, Laurent; Gogin, I.; Abdelmalak, Mohamed Mansour; Faleide, Jan Inge; Eide, Sigurd; Myklebust, R.

doi:10.1002/2017tc004655

Cited by 43 publications

(44 citation statements)

References 135 publications

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“…In these cases the lithospheric mantle is tectonically exhumed into the rock column by asymmetric detachment faulting (Tucholke et al, 2008;Carbotte et al, 2016), exposing mantle peridotites and ultramafics to seawater where serpentinization can occur (Cannat et al, 2010; Figure 2A). We begin our analysis at the initiation of seafloor spreading, neglecting transitional crust that is exposed during continental rifting, although this can also be variably serpentinized (e.g., Zastrozhnov et al, 2018). By estimating the proportion of peridotite present, we also estimate the proportion of the magmatic component.…”

Section: Properties Of Upper Oceanic Lithospherementioning

confidence: 99%

Tectonic Controls on Carbon and Serpentinite Storage in Subducted Upper Oceanic Lithosphere for the Past 320 Ma

2019

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The subduction of upper oceanic lithosphere acts as a primary driver of Earth's deep carbon and water cycles, providing a key transportation mechanism between surface systems and the deep Earth. Carbon and water are stored and transported in altered oceanic lithosphere. In this study, we present mass estimates of the subducted carbon and serpentinite flux from 320 to 0 Ma. Flux estimates are calculated using a fullplate tectonic reconstruction to build a descriptive model of oceanic lithosphere at points along mid-ocean ridges. These points then track the kinematic evolution of the lithosphere until subduction. To address uncertainties of modeled spreading rates in synthetic ocean basins, we consider the preserved recent (83-0 Ma) spreading history of the Pacific Ocean to be representative of the Panthalassa Ocean. This analysis suggests present-day subducting upper oceanic lithosphere contains 10-39 Mt/a of carbon and 900-3500 Mt/a of serpentinite (∼150-450 Mt/a of water). The highest rates of carbon delivery to trenches (20-100 Mt/a) occurred during the Early Cretaceous, as upper oceanic lithosphere subducted during this period formed in times of warm bottom water and the Cretaceous period experienced high seafloor production and consumption rates. Additionally, there are several episodes of high serpentinite delivery to trenches over the last 100 Ma, driven by extensive serpentinization of mantle peridotites exposed at slow spreading ridges. We propose variations in subduction regimes act as the principal control on the subduction of carbon stored in upper oceanic lithosphere, as since 320 Ma the volume of stored carbon across all ocean basins varies by less than an order of magnitude. For pre-Pangea times (<300 Ma), this suggests estimates of seafloor consumption represent a reasonable first-order approximation of carbon delivery. Serpentinite and associated water flux at subduction zones appear to be primarily controlled by the spreading regime at mid-ocean ridges. This is apparent during times of supercontinent breakup where slow spreading ridges produce highly serpentinized crust, and is observed in the present-day Atlantic, Arctic and Indian oceans, where our model suggests upper oceanic lithosphere is up to ∼100 times more enriched in serpentinite than the Panthalassa and Pacific oceans.

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Section: Properties Of Upper Oceanic Lithospherementioning

confidence: 99%

Tectonic Controls on Carbon and Serpentinite Storage in Subducted Upper Oceanic Lithosphere for the Past 320 Ma

2019

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“…Their magma‐rich counterparts, on the other hand, are often lost by subduction due to metamorphic densification. Exposed crustal sections of the magma‐rich end‐member are therefore much less known, and what we do know about their architecture mainly comes from geophysical methods and drill hole data (e.g., Direen & Crawford, ; Gernigon et al, ; Theissen‐Krah et al, ; Zastrozhnov et al, ). In general, these magma‐rich rifted margins show an anomalously thick ocean‐continent transition (~20‐km thickness), commonly referred to as the outer high (Figure ).…”

Section: Introductionmentioning

confidence: 99%

Timing of Breakup and Thermal Evolution of a Pre‐Caledonian Neoproterozoic Exhumed Magma‐Rich Rifted Margin

et al. 2019

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During the terminal stages of Wilson cycles, remnants of magma‐poor margins may be incorporated into the orogens, whereas the magma‐rich margins often are lost in subduction due to low buoyancy. The understanding of magma‐rich margins is therefore mostly based on drill holes and geophysical observations. In this contribution, we explore the temporal evolution and the ambient conditions of a magma‐rich rifted margin preserved within the Scandinavian Caledonides. The Scandinavian Dike Complex was emplaced into a sedimentary basin during the initial breakup and opening of the Iapetus Ocean 615 to 590 million years ago. The dike complex constitutes 70–90% of the magma‐rich, syn‐rift basins and is locally well preserved despite the complex Caledonian history. This contribution provides new observations about the geometry, relative timing, and development of the margin. Jadeite‐in‐clinopyroxene geothermobarometry, titanium‐in‐biotite geothermometry, and garnet isopleth modeling show that the ambient pressure and temperature conditions were similar for the entire dike complex at 0.25 to 0.45 GPa, with contact metamorphic temperatures up to approximately 700 °C. In the northernmost part of the study area, U‐Pb dating of magmatic zircon shows that partial melting of the sedimentary host rock, at relatively shallow levels, occurred at 612 Ma. This shows that the crust was molten already 6 million years before the northernmost dike swarm was emplaced at 605.7 ± 1.8 Ma. We propose that the locally pervasive partial melting occurred due to high geothermal gradients and introduction of mafic melt in the lower crust. These processes significantly reduced the strength of the crust, eventually facilitating continental breakup.

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“…Sedimentary rock samples). In the NE Atlantic, subsidence was important in the Vøring and Møre basins, offshore mid-Norway, leading to the accumulation of up to 8 km of sediments in local depocentres (Scheck-Wenderoth et al, 2007;Abdelmalak et al, 2017a;Theissen-Krah et al, 2017;Zastrozhnov et al, 2018). This subsidence event was followed by another phase of rifting in the late Cretaceous / early Paleocene recorded in the whole North Atlantic area and ended with regional uplift during the Danian (65-62 Ma; Dam et al, 1998a).…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Breakup volcanism and plate tectonics in the NW Atlantic

et al. 2019

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Passive margins are the locus of tectonic and magmatic processes leading to the formation of highly variable along-strike and conjugate margins structures. Using extensive new seismic, gravity, and magnetic datasets, complemented by seabed samples and field work, we investigate the tectonomagmatic evolution of the northwest (NW) Atlantic where breakup-related igneous rocks were emplaced during several Paleogene events associated with lithospheric stretching, continental breakup, and the formation of new oceanic basins. Interpretational methods include integrated seismic-gravity-magnetic (SGM) interpretation and seismic volcanostratigraphy. In addition, seabed and field samples were collected and analyzed to constrain the basin stratigraphy, hydrocarbon potential, and the geochronology and geochemistry of the volcanic sequences. Offshore, 2D seismic data reveal several Seaward Dipping Reflector (SDR) wedges and escarpments in the Labrador Sea, Davis Strait, and Baffin Bay. Onshore, eastward prograding foreset-bedded hyaloclastite delta deposits and overlying horizontal lava successions outcrop on Nuussuaq. These hyaloclastites and lava successions are world class analogues to the Lava Delta and Landward Flows volcanic seismic facies units identified offshore. Our mapping results document an aerial extent of the Paleogene breakup-related volcanics of 0.3×10 6 km 2 , with an estimated volume of 0.5-0.6×10 6 km 3. Basalt samples recovered by dredging the Upernavik Escarpment have late Paleocene to/early Eocene ages, whereas the sedimentary samples provide an excellent seismic tie with the stratigraphy and the geology in this frontier area. From the integrated SGM interpretation, we identify a rapidly thinning crust and changes in top and intra-basement seismic reflection characteristics in the oceanic domain correlated with transition between different magnetic domains. The mapping results were subsequently integrated in a plate tectonic model. The plate tectonic reconstruction and basalt geochronology suggest that the majority of the volcanism in the NW Atlantic

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Cretaceous‐Paleocene Evolution and Crustal Structure of the Northern Vøring Margin (Offshore Mid‐Norway): Results from Integrated Geological and Geophysical Study

Cited by 43 publications

References 135 publications

Tectonic Controls on Carbon and Serpentinite Storage in Subducted Upper Oceanic Lithosphere for the Past 320 Ma

Tectonic Controls on Carbon and Serpentinite Storage in Subducted Upper Oceanic Lithosphere for the Past 320 Ma

Timing of Breakup and Thermal Evolution of a Pre‐Caledonian Neoproterozoic Exhumed Magma‐Rich Rifted Margin

Breakup volcanism and plate tectonics in the NW Atlantic

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