T27 Challenges in Tectonics: Planetary Evolution in Four Dimensions—The New Global Tectonics

Sunday, 22 October 2017
8:00 AM - 12:00 PM
Tahoma 4

STRATIGRAPHIC FRAMEWORK FOR THE PLUME MODE OF MANTLE CONVECTION

Paper number: T27-6
Program: Technical Sessions
Time: 9:25 AM – 9:40 AM

Authors

  • Anke Friedrich Presenting Author
    Ludwig-Maximilians-Universität Munich (LMU), Munich

Abstract

Mantle convection is a fundamental planetary process. Its plate mode is well established and expressed by plate tectonics; its plume mode is equally well established and expressed by interregional-scale geological patterns; I developed a stratigraphic framework to translate the surface effects predicted by the plume mode, which also serves as a methodology to analyze continent-scale geological maps based on unconformities and hiatuses. The surface expression of ascending plumes lasts for tens of millions of years and leaves a distinct record, not only as a > 1-km-high dome above the plume center, but also above the plume head margins and in distal regions (> 1200 km). Regional-scale erosion of the uplifting dome dominates prior to arrival of the plume head at the base of the lithosphere, and is followed by extensional collapse and flood-basalt eruption. A nearly complete sedimentary record may be preserved in distal regions, which did not experience any plume-related uplift. The marginal section of the uplifted dome is the most complex, because it undergoes multiple episodes of uplift and erosion followed by subsidence and sedimentation, and renewed outward-directed uplift and erosion as the plume head collapses and spreads laterally. Thus, marginal regions contain regional-scale “double-unconformity-bounded” stratigraphic successions. Complete global stratigraphic synthesis of plate interiors requires integration of plate- and plume-stratigraphic frameworks. This plume-stratigraphic framework is event-based, interregional, but not global, with time-dependent amplitudes that are significantly larger than global eustatic sea-level fluctuations.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-308724

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