Unconformity development in retroarc foreland basins: implications for the geodynamics of Andean-type margins
Open Access
- 1 December 2021
- journal article
- research article
- Published by Geological Society of London in Journal of the Geological Society
- Vol. 179 (3)
- https://doi.org/10.1144/jgs2020-263
Abstract
Unconformities in foreland basins may be generated by tectonic processes that operate in the basin, the adjacent fold-thrust belt or the broader convergent margin. Foreland basin unconformities represent shifts from high accommodation to non-depositional or erosional conditions in which the interruption of subsidence precludes the net accumulation of sediment. This study explores the genesis of long-duration unconformities (> 1-20 myr) and condensed stratigraphic sections by considering modern and ancient examples from the Andes of western South America. These case studies highlight the potential geodynamic mechanisms of accommodation reduction and hiatus development in Andean-type retroarc foreland settings, including: (1) shortening-induced uplift in the frontal thrust belt and proximal foreland; (2) the growth and advance of a broad, low-relief flexural forebulge; (3) the uplift of intraforeland basement blocks; (4) tectonic quiescence with regional isostatic rebound; (5) the end of thrust loading and flexural subsidence during oblique convergence; (6) diminished accommodation or sediment supply due to changes in sea-level, climate, erosion or transport; (7) basinwide uplift during flat-slab subduction; and (8) dynamic uplift associated with slab window formation, slab break-off, elevated intraplate (in-plane) stress, or related mantle process. These contrasting mechanisms can be distinguished on the basis of the spatial distribution, structural context, stratigraphic position, palaeoenvironmental conditions, and duration of unconformities and condensed sections.Keywords
Funding Information
- National Science Foundation (EAR-1918541)
- National Science Foundation (EAR-1925898)
- National Science Foundation (EAR-1946700)
This publication has 234 references indexed in Scilit:
- From decades to epochs: Spanning the gap between geodesy and structural geology of active mountain beltsJournal of Structural Geology, 2009
- Jurassic onset of foreland basin deposition in northwestern Montana, USA: Implications for along-strike synchroneity of Cordilleran orogenic activityGeology, 2009
- Neogene kinematic history of Nazca–Antarctic–Phoenix slab windows beneath Patagonia and the Antarctic PeninsulaTectonophysics, 2009
- Influence of pre-existing plate-margin structures on foredeep filling: Insights from the Taconian (Blountian) clastic wedge, Southeastern USASedimentary Geology, 2006
- Lithospheric evolution of the Andean fold–thrust belt, Bolivia, and the origin of the central Andean plateauTectonophysics, 2005
- Seismic ridge subduction and topography: Foreland deformation in the Patagonian AndesTectonophysics, 2005
- Formation of internally drained contractional basins by aridity‐limited bedrock incisionJournal of Geophysical Research, 2003
- Concept of continuum as opposed to periodic tectonism in the AndesTectonophysics, 1996
- Subduction of diverging plates and the principles of slab window formationTectonophysics, 1996
- Syntectonic unconformities of the Alto Cardener, Spanish Pyrenees: a genetic interpretationSedimentary Geology, 1976