1 / 12

Evolution of the Magnitogorsk oceanic arc system (Devonian, southern Urals)

Evolution of the Magnitogorsk oceanic arc system (Devonian, southern Urals). Bernd Buschmann (TU Bergakademie Freiberg) based on major cooperation with: Peter Jonas (Freiberg) Victor Puchkov (Ufa) Valery Maslennikov, Victor Zaykov (Miass).

decker
Download Presentation

Evolution of the Magnitogorsk oceanic arc system (Devonian, southern Urals)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Evolution of the Magnitogorsk oceanic arc system (Devonian, southern Urals) Bernd Buschmann (TU Bergakademie Freiberg) based on major cooperation with: Peter Jonas (Freiberg)Victor Puchkov (Ufa)Valery Maslennikov, Victor Zaykov (Miass) IGCP 453 – Uralides / August 2nd – 12th, 2004

  2. Major tectonostratigraphic-structural zones of the southern Urals

  3. Tectonostratigraphic-structural zones related to arc-continent accretion

  4. Scheme of arc-continent collision in the southern Urals(from Matte 1998, after Chemenda et al. 1997)

  5. Generalizedgeological mapof the Magnitogorsk Zone

  6. Schematic tectonostratigraphic column for N part of Magnitogorsk Zone

  7. Schematic cross section of N part of MOAS in Early Frasnian time (onset of arc-continent docking)

  8. 2D scheme of evolution of the MOAS

  9. Some major points to discuss • environment responsible for generation of boninitic rocks in initial arc complex • vergency of subducting slab during oceanic arc growth • geotectonic environment of formation of Famennian calc-alkaline volcanics a eastern margin of Magnitogorsk Zone • structure development of the accretionary complex by 1. arc-continent docking 2. subsequent compression (hypercollision - wrench tectonics)

  10. Some arguments against W-vergent subduction at eastern margin of MOAS Southern Urals situation • mineral closing ages (garnet, sphene, phengite) in HP-rocks of subducted continental margin 380-370 Ma • requires presence of E-vergent subducted slab at western board of MOAS before 370 Ma • contemporaneous W-vergent subduction at eastern margin of MOAS (if feasible at all) should have resulted in strong extension in overriding plate – no signs for such extension

  11. Some arguments against W-vergent subduction at eastern margin of MOAS Modern examples W Pacific – no microcontinents involved in arc-continent collision Timor subduction beneath NW Australian margin, Banda arc approaching island of Timor is emerged part of accretionary complex Taiwan oblique arc-continent collision accretionary complex first to emerge in front of docking arc Timor + Taiwan – shelfal sea between emerged accretionary complex and continental coastline - seastrait between emerged accretionary complex and extinct arc

  12. Good weather and fruitful discussions for our field trip! Landscape of contact between Irendyk arc complexes (foreground) and Karamalytash rocks (background) W of Sibai town

More Related