T7 Earth Surface Processes in Tectonically Active and Unstable Regions I

Sunday, 22 September 2024
8:00 AM - 12:00 PM
210B

GEODYNAMIC STRATIGRAPHY — MAPPING STRATEGIES TO LINK MODELS OF MANTLE DYNAMICS TO SURFACE PROCESSES ON GEOLOGICAL SCALES

Paper number: T7-2
Program: Technical Sessions
Time: 8:10 AM – 8:25 AM

Authors

Abstract

Geodynamicists suggest that mantle convection in terrestrial planets creates dynamic topography — a long-wavelength, low-amplitude signal. This predicts transient vertical Earth surface movements of 1–2 km across thousands of kilometers, including continental interiors. However, experts using high-resolution geological, sedimentological, and geomorphological data struggle to find clear evidence supporting such dynamic models. Regional-scale stratigraphic techniques, like sequence stratigraphy used in hydrocarbon exploration, invoke unconformities on multiple scales but make it difficult to correlate distinct geodynamic events.

To address this problem, I propose an event-based stratigraphic mapping approach based on a theoretical geodynamic framework. This involves identifying tectonic events and features (e.g., magmatic arcs, flood basalts, uplifted domes) and mapping regional-scale stratigraphic unconformities to distal regions. This approach is similar to how paleoseismologists examine event horizons, small unconformities adjacent to fault scarps that preserve records of the Earth's surface at the time of earthquake rupture.

This event-based stratigraphic mapping method (EVENT-STRAT) allows analysis of geological events on maps compiled at regional to continental scales. The technique connects local work to a continent-scale framework, identifying transient patterns related to plate tectonics and other mantle-derived dynamic events. EVENT-STRAT visualizes geological effects from both the plate and plume modes of mantle convection. The toolbox includes the hiatus mapping method (Friedrich 2019, Geological Magazine) and the event-based stratigraphic framework mapping (Friedrich et al. 2018, Gondwana Research). EVENT-STRAT involves multiple polygonal stacking to analyze various stratigraphic event horizons, such as hiatus surfaces and unconformities.

The main challenge is merging high-temporal resolution on chronostratigraphic charts with continent-scale geological maps. This effort requires international collaboration involving geological surveys to compile the next generation of global and continent-scale geological maps to test interregional-scale tectonic and geodynamic models.

Geological Society of America Abstracts with Programs. Vol. 56, No. 5

doi: 10.1130/abs/2024AM-405616

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