- 1Institute of Earth Sciences, University of Lausanne, Lausanne, Switzerland
- 2College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
- 3Department of Earth Sciences, Simon Fraser University, Burnaby, Canada
- 4Leibniz Institute for Applied Geophysics (LIAG), Geozentrum Hannover, Hannover, Germany
- 5Department of Earth Sciences, National Central University, Taiwan
- 6Department of Geosciences, National Taiwan University, Taipei, Taiwan
An analysis of allogenic forcing on shallow-marine strata of the Miocene–Pliocene Kueichulin Formation in the Taiwan Western Foreland Basin shows that changes in the sedimentary record were predominantly driven by: 1) orogenesis and basin subsidence, 2) precession-driven changes in hydroclimate, and 3) obliquity-driven changes in atmospheric and ocean circulation.
The transition from a wave-dominated open shelf to a tide-dominated shallow-marine deltaic environment was influenced by a combination of basin subsidence and the denudation of Taiwan. The rapid deepening of the Western Foreland Basin near 5400 Ka and low sedimentation rates resulted in the formation of lower offshore to distal delta front environments, characterized by limited fluvial and storm influences. Shallow-marine deltaic environments formed as sediment from Taiwan filled the Western Foreland Basin, as a result of accelerated uplift after 4920 Ka, and rapid erosion of the orogen by tropical cyclone precipitation intensified. Tidal currents also intensified as the paleo-Taiwan Strait became shallower and narrower with continued uplift and southwest migration of Taiwan. The sedimentary record also shows a strong link between sedimentation and hydroclimate, driven by eccentricity-modulated precession. Tropical cyclone deposition corresponds to precession maxima, with amalgamated beds that form during periods of sea-level minima. Periods of high obliquity and associated changes in atmospheric and ocean circulation also resulted in a strengthening of tidal currents, recorded as a prevalence of tidal beds in the stratal record.
The findings of this study demonstrate the effectiveness of shallow-marine strata as a paleoenvironmental archive with the potential to resolve the influence of competing allogenic controls on sedimentary systems, which is crucial for understanding how depositional systems responded to climate change, tectonic activity, and sea-level fluctuations throughout Earth’s history.
How to cite: Hsieh, A. I., Vaucher, R., MacEachern, J. A., Zeeden, C., Huang, C., Lin, A. T., Löwemark, L., and Dashtgard, S. E.: Relative influence of allogenic forcings on shallow-marine sedimentary archives, Taiwan Western Foreland Basin, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8426, https://doi.org/10.5194/egusphere-egu25-8426, 2025.
