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Similar to Parry_2012_30th_Nordic_Geological_Winter_Meetin_Rekjavik_Opening_of_the_ North_ Atlantic_&_Norwegian – Greenland_Sea_Basin_Lessons_from_the_South_Atlantic
Similar to Parry_2012_30th_Nordic_Geological_Winter_Meetin_Rekjavik_Opening_of_the_ North_ Atlantic_&_Norwegian – Greenland_Sea_Basin_Lessons_from_the_South_Atlantic (20)
Parry_2012_30th_Nordic_Geological_Winter_Meetin_Rekjavik_Opening_of_the_ North_ Atlantic_&_Norwegian – Greenland_Sea_Basin_Lessons_from_the_South_Atlantic
- 1. • Chris Parry OPENING OF THE NORTH ATLANTIC & NORWEGIAN – GREENLAND SEA BASIN – LESSONS FROM THE SOUTH ATLANTIC
- 2. Fracture Zones: Origins, Expression and Evidence Northeast Greenland 12/2011 Oceanic Fracture Zones: • Archaean basement control, • Set up initial basin architecture, • Influence reservoir distribution, • Provide migration pathways, • Set up traps. USA Eastern Seaboard: Fracture Zones first set up during opening of Iapetus Ocean, re-used during Atlantic opening, still active!
- 3. Wilson Cycles and Tectonic Inheritance: Eastern Seaboard USA 1, Grenville Orogeny: Pre-Iapetus Ocean closed 2, Iapetus Ocean opens 3, Caledonian Orogeny: Iapetus Ocean closed 4, Iapetus Ocean opens again a.k.a. Atlantic Modern Fracture Zones linked to Iapetus Fracture Zones Thomas, W.A., 2006, GSA Today, pp. 4 - 11 1889 Charleston Earthquake (magnitude 6.6 - 7.3) located on Pangaea break up fault. Similar faults found along entire East Coast, which are active due to present day plate movements. 1929 Grand Banks Earthquake (magnitude 7.2) 2011 Virginia Earthquake (magnitude 5.8). Reverse fault formed during Taconic and Alleghenian Orogenies, reactivated during Pangaea breakup in Mesozoic and further reactivated during Cenozoic
- 4. Modified after Lowell, J.D., 1972, Geol. Soc. Am. Bull., pp. 3091 - 3102 Eurasian Plate North American Plate • Two plates moving at low convergent angle causes space problem. • Easiest direction for relief is upwards. • Upthrusts are not necessarily symmetrical. • Faults coalese and anastomose with depth. Svalbard: Convergent Strike Slip or Transform Motion Upthrust Zone
- 5. Tectonic lineaments of Norway & Sweden Finnmark North MTFC West Southwest East Norway NW-SE to WNW-ESE lineament populations: - clearly different from other populations, since almost evenly distributed throughout study area. - represent inherited structural grain, arising from a megafracture pattern imposed on the western Fennoscandian Shield during Proterozoic time. - evidence from northern Scandinavia and Russia shows, in fact, that several of these NW-SE to ENE-WSW lineaments originated during the Archaean. After: Gabrielsen, R. H. et al., 2002, Norsk Geologisk Tidsskrift, Vol. 82, pp. 153 - 174.
- 6. • Accreted as series of terranes in the Precambrian • Accretion occurred before most brittle deformation Pless, J. et al, 2010, AAPG, New Orleans – oral & poster presentation & Williams, G.E. & Foden, J., 2011, Earth-Sci. Rev., pp 34 - 49. • Prominent NE-SW & NW-SE fault trends • NW-SE faults produce the longest lineaments • Originate in Archean (2490-2400 Ma): Steep NW-SE shear zones formed due to dextral transpression • Reactivated during all subsequent tectonic episodes Lewisian Gneiss Complex
- 7. I – Intra-Palaeocene Unconformity North Atlantic & Norwegian - Greenland Sea Deformation History 1 2 3 4 5 7 1 2 3 4 5 6 7 8 9 6 Iapetus Ocean Spreading Variscan Orogeny 1 2 3 4 5 6 7 8 NE Greenland AFTA Cooling Events Break-up & early opening of Central Atlantic Regional extension in North Atlantic region Limited seafloor spreading southern North Atlantic Focus of rifting in North Atlantic region Opening of southern North Atlantic I - Main rift axis northern North Atlantic Main rift axis moved to Labrador Sea Seafloor spreading Labrador Sea Rifting in Norwegian-Greenland Sea area Break-up Norwegian-Greenland Sea area - Magmatism Seafloor spreading Ægir Ridge Change in spreading direction Norwegian-Greenland Sea area Uplift of areas surrounding Norwegian-Greenland Sea area Glaciations – continued uplift & erosion Seafloor spreading Kolbeinsey Ridge Seafloor spreading Mohns Ridge Seafloor spreading Lena Trough - Knipov Ridge (Fram Strait) Break-up & early opening of Southern Atlantic Caledonidian Orogeny Gravitational Collapse 8 9 Principal stress/strain axes at low angle to foliation Reactivation of pre-existing ”weak” foliation planes U Cretaceous Inversion Early Cimmerian Mid Cimmerian Late Cimmerian Laramide Orogeny Extension/Seafloor Spreading Inversion/Compression Legend Block Diagrams from Pless, J. et al, 2010. Grenville Orogeny I – Base Tertiary Unconformity I – Mid-Miocene Unconformity I - Plate reorganization I – Upper Eocene Unconformity I – Mid-Oligocene Unconformity I – Base Neogene Unconformity
- 8. SE Greenland Guarnieri, P., 2011, Bull. Geol. Soc. Den., 23, pp. 65-68. Simplified after Tegner, C. et al, 2008, Lithos, pp. 480 - 500 Bathymetric data clearly illustrate the presence of additional Fracture Zones, (not illustrated for sake of clarity).
- 9. UK Norway Ritchie, J. D. et al., 2008, Geol. Soc. Lond. Spec. Publ., 306, pp. 121 – 136. Reproduced with permission of the Geol. Soc. • Two plates moving at low convergent angle causes space problem (plate reorientation due to opening of Fram Strait?) • Easiest direction for relief is upwards. • Wrench fault flower structures are not necessarily symmetrical. • Faults coalese and anastomose with depth. . . ++ ? ? Oceanic CrustContinental Crust Pelagic sediments inversion Gaina et al., 2009* ”mild inversion”, ”several compressive events” Oceanic crust inversion East Jan Mayen Fracture Zone Central Jan Mayen Fracture Zone * Gaina, C. et al, 2009, J. Geol. Soc., pp. 601 – 616.
- 10. Norwegian - Greenland Sea The Central and Southern Atlantic Ocean simple symmetric spreading model can be used to explain the opening of the Norwegian – Greenland Sea.
- 11. Eocene - Oligocene A. Symmetrical opening in Early Eocene LEGEND Spreading Ridge Hot spot Fracture Zones Relative Plate Motion: C13 C24 Present Age of Oceanic Crust: Chron 24 – 21 E Eocene Chron 21 – 13 M/L Eocene Chron 13 – 6 Oligo/E Mio C21 C24 C24 C21 Additional FZs present e.g. Westray A 0 Kilometers 250 C. Oligocene plate re-organisation, change of spreading direction: Fram Strait opening - relative plate motion changes from right-lateral shear to oblique divergence (left-lateral shear on Victory FZ) C13C6 C6C13 Slower spreading rate C 0 Kilometers 250 B. Symmetrical spreading Middle - Late Eocene Slower spreading rate C13 C21 C21 C13 B 0 Kilometers 250
- 12. C6Present PresentC6 F 0 Kilometers 250 F. Middle Miocene – Present: Kolbeinsey Ridge spreading C13C6 C6C13 E 0 Kilometers 250 E. Early Miocene: Kolbeinsey Ridge becoming active C13C6 C6C13 D 0 Kilometers 250 LEGEND Spreading Ridge Hot spot Fracture Zones Relative Plate Motion: C13 C24 Present Age of Oceanic Crust: Chron 24 – 21 E Eocene Chron 21 – 13 M/L Eocene Chron 13 – 6 Oligo/E Mio Chron 6 – 0 M Mio/Recent Oligocene volcanics Miocene volcanics Miocene - Recent D. Oligocene: change of spreading from Ægir- Kolbeinsey Ridge. Westerly migration of volcanic centre, lava flows locally obscure Eocene magnetic anomalies Flood basalts cover future Jan Mayen Micro-Continent
- 13. C24 C13 Present C13 C24 Present C13 C24 Present C24 C13 Present NW European plate N American plate Plate vectors from Engen et al., 2008* * Engin, Ø. et al, 2009, Tectonophysics, pp. 51 – 69.
- 14. CONCLUSIONS A simple symmetric spreading model can be used to explain the opening of the Norwegian – Greenland Sea. NW-SE trending, coast perpendicular fracture zones, are recognized regionally in the deepwater and adjacent shelf, linked to onshore pre-Cambrian basement fabric. Transtensional, transpressional and inversion structuring associated with reactivation of the Mid - Ocean Ridge transform boundaries/fracture zones is pervasive throughout the North Atlantic and Norwegian – Greenland Sea (as seen throughout the Atlantic Ocean). FZ Offshore/Onshore linked shear zones control: Sediment entry points, Provide hydrocarbon migration routes, Create trapping geometries, & Allow development of new exploration models. Acknowledgements: ConocoPhillips management for support for the publication of this article, Jennifer Pless and Professor Bob Holdsworth, Durham University (Lewisian Outcrop Project), Clair Field partnership (permission to share the Lewisian Outcrop Project ongoing research).
- 15. Takk fyrir athyglina og takk fyrir mig! Skjaldargrunn Eo - Oligocene Iceland! Iceland SE Greenland 3D Topography/Bathymetry