Stratigraphic Architecture and Lithofacies Analysis: Evidence for Development of the Pliocene-Holocene Taichung Foreland Basin, Central Taiwan

Abstract

The Taichung foreland basin, sub-basin of the Taiwan foreland basin, has developed since Pliocene. We studied stratigraphic architecture and the lithofacies of the Taichung basin in detail. We recognized eleven lithofacies, which are grouped into ten facies associations. Based on facies association analysis, we suggest that the development of the Taichung basin can be divided into four stages accompanied by syn-depositional deformation characterized by westward propagating thrust faults.Prior to 2.78 Ma, the basin was characterized by offshore environment during underfilled stage. Later, the Shuangtung Fault located to the east of the Western Foothills began to thrust westward and uplifted the Tertiary strata, which supplied sediments to basin between the Shuangtung and Chelungpu faults in initial filled stage. About 1 Ma, the Chelungpu Fault started to thrust westward and uplifted the Western Foothills, which shed fluvial sediments to fill basin between the Chelungpu and Tachia faults. After 0.46 Ma, the Tachia Fault began to thrust westward and strata immediately to the east of the Tachia Fault were uplifted to form ramps, producing Houli and Tatushan tablelands. The basin-filling reached the overfilled stage when the Chingshui Coastal Plain is dominated with fluvial facies.The Taichung foreland basin is bounded by Tachia and Shuangtung faults with the Chelungpu Fault in the middle and formed by active, sequentially propagating westward thrust faults from Pliocene to Pleistocene. The youngest Tachia Fault carried the piggyback basin in front of the older Chelungpu Fault, representing similar style to piggyback basins of the Po Basin and the Ebro Basin in Europe.

Deciphering cumulative fault slip vectors from fold scarps: Relationships between long‐term and coseismic deformations in central Western Taiwan

“…S . Chen et al ., 2001; Chen and Chen , ; Simoes et al ., ; Lin et al ., ; Kao et al ., ]. However, present‐day river incision of the northern Taichung Basin, incised late Quaternary lateritic alluvial deposits at the northern end of the basin, and shallower depths and lower thicknesses of Plio‐Pleistocene strata than further south [e.g., Yue et al ., ] indicate the occurrence of broad tectonic uplift responsible for lower sedimentation rate in this area.…”

“…Additional base-level changes are due to sedimentation in the footwall and regional tectonic uplift. Sedimentation rates of 2 ± 1 mm/a were reported from borehole data and field survey in central Western Taiwan [W. S. Chen et al, 2001;Simoes et al, 2007a;Lin et al, 2008;Kao et al, 2013]. However, present-day river incision of the northern Taichung Basin, incised late Quaternary lateritic alluvial deposits at the northern end of the basin, and shallower depths and lower thicknesses of Plio-Pleistocene strata than further south [e.g., Yue et al, 2005] indicate the occurrence of broad tectonic uplift responsible for lower sedimentation rate in this area.…”