Possible links between the development of Plio-Pleistocene coral reef limestones and thrust migration in southwestern Taiwan

The southwestern Taiwan is part of a Plio-Pleistocene foreland basin filled with thick siliciclastic sediments. Embedded in these sequences are several lenticular reef limestones which are characterized by: (1) a rapid transition from underlying deep-water siliciclastic mudstones upward to reef limestones, (2) a lateral interfingering with deep-water siliciclastics, (3) an overlay of terrestrial deposits or of no other strata, implying an emergence above sea level since the reef formation, and (4) a location closely associated with anticlines. The authors propose that the majority of the Pleistocene reef limestones in southwestern Taiwan, including the Tudikungchi, Takangshan, Hsiaokangshan, Panpingshan and Kaohsiung Limestones, were deposited on local structural highs formed by thrust-induced anticlinal ridges that resulted from the cratonward migration of the orogen. They also speculate that the overall age-spatial distributions of these reef limestones could possibly represent thrust-front migration of the foreland basin.