Prosjektleder: Laurent Gernigon
Breakup and Microcontinent formation: Investigation of the Jan Mayen and conjugate margins system
The understanding of continental break-up and margin formation and evolution is a first order problem in Geosciences and hydrocarbon exploration. Recent advances in studying passive margin formation revealed the complex transition between rifting, break-up and seafloor spreading. Moreover, the classical concept of volcanic and non-volcanic margins seems to become obsolete and new insight into the role of kinematics versus magma and rifting dynamics needs to be gained through new observations and modelling. The transition between volcanic and non-volcanic segments of passive margins and the formation of microcontinents proves to be an exciting new territory where complex processes which involve pre-existing structures, plate kinematics and mantle dynamics can be analysed and better understood.
Figures 1: 3D elevation model of the Norwegian-Greenland Sea and surrounding margins. The Jan Mayen microcontinent (JMMC) represents part of the atypical bathymetry observed north of Iceland. The JMMC is surrounded by oceanic crust, including the Norway Basin to the East and the Iceland Plateau to the East The early history of the JMMC is traditionally characterized by a first phase of continental breakup resulting in the formation of volcanic margins during the splitting of Norway and the coupled Greenland/Jan Mayen system in Early Tertiary (~55 Ma ago). Before breakup, the proto-JMMC was located between the Faeroes Plateau and the outer Vøring Basin (dashed ellipsoid area), characterized by a complexes system of Mesozoic basins partly cover by basaltic rocks. Around Oligocene time, sea-floor spreading along the Aegir Ridge decreased until it became extinct and the spreading axis "jumped” westwards to initiate the Kolbeinsey Ridge. The relocation of the spreading ridge from the aborted Aegir Ridge to the Kolbeinsey Ridge resulted in the final separation of the JMMC from the Greenland Plate around 25 Ma ago. EJMFW and WJMFZ : East and West Jan Mayen Fracture Zones.
We propose to tackle the passive margin and microcontinent formation within a complex system that involves regional plate kinematics and mantle dynamics by undertaking a detailed study of the Norwegian and Greenland margins and the adjacent Jan Mayen Microcontinent (JMMC)(Fig.1).
The spatial and temporal evolution of discrete rift systems as extensional processes localize and evolve towards the accretion of oceanic crust and the interaction between margin kinematics, magmatic and mantle processes combined with the formation or microcontinents are not thoroughly understood. The study of JMMC is not meaningful only for a deeper understanding of a classical microcontinent formation, but also for a better hydrocarbon assessment of the Norwegian and Faeroes frontier areas. Therefore, we propose to undertake an integrated approach in order to improve, test and model our current knowledge of the JMMC and its relevance for the understanding of the passive margin conjugate system (eg. the Møre and East Greenland margins) and continent-ocean transitions.
Few models have tempted to understand the mechanisms involved in microcontinent initiation and development. An integrated approach that would analyse and refine the margin architecture, breakup timing, oceanic crust evolution, change in plate boundaries, microcontinent evolution and implication of magma-tectonic processes using geophysical and geological data and several modelling techniques will constitute the first detailed study of this type.