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Distinct Responses of Intraplate Sedimentation to Different Subsidence Mechanisms: Insights From Forward Landscape Evolution Simulations
Author(s) -
Chang Ching,
Liu Lijun
Publication year - 2019
Publication title -
journal of geophysical research: earth surface
Language(s) - English
Resource type - Journals
eISSN - 2169-9011
pISSN - 2169-9003
DOI - 10.1029/2018jf004905
Subject(s) - geology , intraplate earthquake , thermal subsidence , lithosphere , tectonic subsidence , subsidence , lithospheric flexure , gravity anomaly , ocean surface topography , tectonics , back stripping , tectonic uplift , geomorphology , fluvial , structural basin , paleontology , sedimentary basin , sedimentary basin analysis , geodesy , oil field
Both the surface processes associated with large intracontinental basins and their underlying geodynamic mechanisms remain unclear. Proposed models include flexural deformation due to orogenic loading, isostatic subsidence in response to lithosphere extension, and dynamic subsidence arising from sublithospheric mantle downwelling. Here we use forward landscape evolution modeling to quantitatively investigate the surface process response to various types of tectonic subsidence during intraplate sedimentation. We find that isostatic subsidence causes continuous accumulation of sediment through time with a largely stable pattern of fluvial drainage. In contrast, dynamic subsidence results in fast intraplate sedimentation followed by regional unconformities and continental‐scale reorganization of fluvial networks. Our quantitative simulations reveal that the traditional 1‐D isostatic backstripping approach may lead to erroneous estimates of the past tectonic subsidence from the preserved sedimentary records: for lithospheric elastic thickness ( T e ) < 50 km, the flexural effect leads to larger (smaller) apparent subsidence at the center (rim) of the basin, compared to the true subsidence; for T e > 50 km, broadscale flexural support leads to underestimated subsidence throughout the basin. Subparallel tilted strata are a unique stratigraphic feature associated with spatially migratory dynamic subsidence followed by dynamic rebound. Their characteristic slope provides a quantitative constraint on the spatiotemporal pattern of dynamic subsidence. The Cretaceous Western Interior Seaway provides an example of this type of basin fill. We demonstrate that quantitative, forward landscape evolution modeling can help decipher the relationship between intraplate sedimentation and the underlying tectonic drivers.