Evolution of the Pacific Margin: Progress and Future Jeremy Hourigan, Yale University


Download 490 b.
Sana22.02.2017
Hajmi490 b.
#1008


Evolution of the Pacific Margin: Progress and Future

  • Jeremy Hourigan, Yale University

  • Sergei D. Sokolov, GIN-RAS Moscow

  • Aleksandr I. Khanchuk, FEGI-RAS, Vladivostok


Outline of Progress

  • Pre-Late Cretaceous Pacific Convergent Margin

  • Sea of Okhotsk

  • Olyutorsky Arc-Collision zone, Kamchatka

  • Neotectonics - upper crustal response to plate margin processes

  • Geophysics - structure of the modern subduction zone



Terrane Map: Nokleberg et al, 1998



Progress: Pre-Late Cretaceous Convergent Margin evolution

  • Laboratory of Tectonics of Oceanic and Perioceanic zones (Sokolov)

    • Pekul’ney Range
    • Koryak Highlands
    • Taigonos Peninsula
  • Transform-margin evolution in Primoriye (Khanchuk)



Outline of Progress

  • Uda-Murgal Arc evolution

    • Improved understanding of Pacific plate geometry and kinematics from the record far-traveled material in accretionary prism (geochemistry, radiolarian stratigraphy, and paleomagnetic)
    • Tectonic reconstruction of Pre-mid Cretaceous NE Russian Margin


Modern extent of the Uda-Murgal Arc

























Okhotsk-Chukotka Volcanic Belt



Okhotsk Chukotka Volcanic Belt



Outline of Progress

  • Sea of Okhotsk

    • Sredinniy Range (eastern edge of Okhotsk Sea microplate?)
    • Seasat gravity dataset
    • Analog modeling asymmetric back arc extension
    • S-wave tomography of sub-Okhotsk mantle
    • Thermochronologic constraints for extension in the Magadan Basin




Existing models for the origin of the Okhotsk Sea Basement



Structure of the Exterior OCVB



Reconstruction of the Late Cretaceous – Early Tertiary margin



Surface Wave Diffraction Tomography



Outline of Progress

  • Olyutorsky arc-continent collision zone

    • New timing constraints for arc-continent collision (Soloviev, Garver and Brandon)
    • High-grade roots of the Collision zone in the Sredinniy Range


Arc-continent collision between Late K – Paleocene Olyutorsky Arc and the northeast Russian continental margin

  • Arc-continent collision between Late K – Paleocene Olyutorsky Arc and the northeast Russian continental margin

  • Timing constrained by fission-track grain-age stratigraphy and biostratigraphy from marginal sandstone units in the lower plate

  • Timing estimates: 55 – 45 Ma

  • Cross-cutting granite and overlapping Kinkil volcanic rocks of the West Kamchatka Belt: 45 Ma (U/Pb zircon TIMS, Garver, 2001)









Simplified geologic map of the Sredinniy Range



Kolpakova Gneiss: migmatite



Accumulation of protoliths



Outline of Progress

  • Neotectonics

    • Tephrachronologic, marine terrace record of vertical motion along coastal Kamchatka (Bourgeois group)
    • Accretion history of Cape Terranes (Mann and co-workers; Gaedicke and others)












Outline of Progress

  • Geophysics – Modern subduction zone structure

    • SEKS experiment (Side-Edge of the Kamchatka Slab)
    • Crustal Structure of Kamchatka and Mainland Russia
    • Mantle velocity structure beneath the Sea of Okhotsk


Workshop objective

  • Establish links between geodetic, neotectonic, structural, thermochronologic, and geophysical disciplines to understand the evolution of the Pacific margin at a range of time and length scales.



Discussion objectives

  • Establish links between geodetic, neotectonic, structural, thermochronologic, and geophysical disciplines to understand the evolution of the Pacific margin at a range of time and length scales  cross-disciplinary approach.



Discussion objectives

  • The southern continuation  Understanding linkages with Mongol-Okhotsk Belt and Sikhote-Alin Margin

  • Radiation of angiosperms – climatic and paleobotanical implications (EARTHTIME Iniative)

  • The Sea of Okhotsk

  • Origin of basement

  • Time-space patterns of extensional basin formation and strike-slip faulting

  • Role of Pacific plate roll-back, strike-slip modification, and Asian extrusion

  • If the Sea of Okhotsk is a microplate, when did it achieve the microplate character?



Discussion objectives

  • Kamchatka

    • Cross disciplinary projects that address the evolution of the Aleutian Kamchatka junction
    • Evolution of high grade metamorphic rocks in a collage of low-grade accreted terranes (Sredinniy, Ganal and Khavyven Ranges)


Download 490 b.

Do'stlaringiz bilan baham:




Ma'lumotlar bazasi mualliflik huquqi bilan himoyalangan ©fayllar.org 2024
ma'muriyatiga murojaat qiling