Sedimentary Environmental Evolution of the Western Taiwan Shoal Area since the Late Pleistocene

Chipeng He,Dongling Li,Longbin Sha,Zheng Li,Xianfu Li,Lu Dai,Jiabing Tang,Dongbo Zhao

doi:10.3390/jmse9101150

Chipeng He, Dongling Li + Show 6 more

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https://doi.org/10.3390/jmse9101150

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Abstract

A new pollen analysis and major and trace element contents were conducted on a 40 m long gravity core recovered from the Taiwan Shoal (sand ridges), south of the Taiwan Strait, beginning in the Late Pleistocene. The changes in the pollen assemblage and concentration represent the climate change around the Taiwan Shoal and the strength of the Zhe-Min Coastal Current, whereas variations in major and trace element contents can imply the source of the sediments in the Taiwan Shoal, which are correlated with the rise or fall of the sea level with increased marine dinoflagellate cysts. The interval of 40–30 m was characterized by high pollen and spore concentrations, and evergreen Quercus was dominant taxon, which indicates a warm sedimentary environment, and the surrounding area of the Taiwan Shoal were covered by a tropical and subtropical broad-leaved forest. There were no pollen and spores from 30–24 m, which indicates a strong hydrodynamic sedimentary environment, and most of the Taiwan Shoal might have been experience subaerial exposure. The interval of 24–17 m was characterized by the reappearance of pollen and spores, as well as marine dinoflagellate cysts and foraminifera, suggesting the climate was warm and wet in the study area and an apparent marine sedimentary environment with relatively high sea level. Deciduous Quercus dominated the interval of 17–12 m, which indicated that the climate was relatively cool, corresponding to the end of Marine isotope stages3 (MIS3) to the Last Glacial Maximum accompanied by weathering and denudation. Above 12 m, the low pollen concentration with increased marine dinoflagellate cysts and foraminifera abundance suggested a marine sedimentary environment in the Taiwan Shoal. The high concentrations in Pinus corresponds to Holocene high sea level.

Highlights

IntroductionThe Taiwan Strait, a waterway between Mainland China and Taiwan, is a relatively shallow shelf sea (average 60 m in water depth) dominated by tidal currents [1]
The Taiwan Strait, a waterway between Mainland China and Taiwan, is a relatively shallow shelf sea dominated by tidal currents [1]
The foraminifera analysis of 16 cores in the western Taiwan Strait shows that the strata of the Taiwan Strait since the late Quaternary can be divided into five layers, and the Taiwan Strait was a neritic environment in the Last Glacial period [4]

Summary

Introduction

The Taiwan Strait, a waterway between Mainland China and Taiwan, is a relatively shallow shelf sea (average 60 m in water depth) dominated by tidal currents [1]. It is considered an important channel for material and energy resource exchange (Figure 1). Wu [3] found that the distribution pattern of rare-earth elements in the Taiwan Shoal is similar to that of granite in Fujian and the East China. Lan et al [5,6] reported that the coarse sand at ~20 ka BP in the Taiwan Shoal contained The foraminifera analysis of 16 cores in the western Taiwan Strait shows that the strata of the Taiwan Strait since the late Quaternary can be divided into five layers, and the Taiwan Strait was a neritic environment in the Last Glacial period [4].

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