Stratigraphic modeling of the Western Taiwan foreland basin: Sediment flux from a growing mountain range and tectonic implications

Stefan Nagel,Andrew Tien-Shun Lin,Sean Willett,Didier Granjeon,Sébastien Castelltort

doi:10.1016/j.marpetgeo.2018.05.034

Stefan Nagel, Andrew Tien-Shun Lin + Show 3 more

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https://doi.org/10.1016/j.marpetgeo.2018.05.034

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Abstract

Abstract Sediment flux signals from source to sink in foreland basins preserve a record of tectonics, sea level and climate through erosion and sedimentation. However, longitudinal sediment transport often occurs in foreland basins, thus removing part of the orogenic material flux from foreland basin records. Here we use mass balance calculation and stratigraphic simulations of sediment fluxes for the Taiwan orogen to provide an order of magnitude estimate of how much orogenic material may bypass a foreland basin. Our results indicate a significant, potentially more than 50%, mismatch between sediment volume currently preserved in the basin and the amount of material presumably eroded from the orogen since the onset of collision in Taiwan. This suggests either a significant overestimation of average erosion rates over the period concerned with orogenic development of Taiwan, or it supports previous paleogeographic work suggesting that longitudinal sediment transport in the paleo-Taiwan Strait served as a major bypass conduit of importance for the establishment of a steady state orogen. We identify candidate submarine topography in the South China Sea that may preserve Taiwan's missing erosional mass.

Highlights

Sediment fluxes within foreland basins exert a primary control on basin architecture involving interactions between tectonics, sea level and climate through erosion and sedimentation (e.g., Allen et al, 2013, Castelltort et al, 2015, Flemings and Jordan, 1989, Posamentier and Allen, 1993)
Our results indicate a significant, potentially more than 50%, mismatch between sediment volume currently preserved in the basin and the amount of material presumably eroded from the orogen since the onset of collision in Taiwan
The sedimentary system of the Taiwan foreland basin is governed by oblique collision between Luzon volcanic arc and the Asian passive margin

Summary

Introduction

Sediment fluxes within foreland basins exert a primary control on basin architecture involving interactions between tectonics, sea level and climate through erosion and sedimentation (e.g., Allen et al, 2013, Castelltort et al, 2015, Flemings and Jordan, 1989, Posamentier and Allen, 1993). The western foreland basin in Taiwan (Fig. 1A) is a suitable place to study interactions between tectonics and sediment fluxes because it is very young (5-6 Ma) and still very active (modern seismicity and extreme climate conditions). In this basin, southwestward ongoing oblique collision between the Luzon volcanic arc and the continental shelf of Eurasia Taiwan orogen is emblematic of the distinct classical evolutionary stages (underfill to overfill, flysch to molasse) that characterize many ancient foreland basin systems such as in the Molasse basin of the Alps (Allen et al, 1991), the Bradanic Trough in the Apennines (Tropeano et al, 2002), the Solomon Sea in Papua

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