An evolutionary model for the Holocene formation of the Pearl River delta, China

Abstract

This paper reconstructs the evolutionary history of the Pearl River delta over the last 9000 years and investigates land—sea interaction in a large deltaic complex which formed under the influence of Asian monsoon climate. Specifically, this research examines the delta evolution in the context of three driving mechanisms: (1) rising sea level that influences the available accommodation space, (2) fluvial discharge as influenced by monsoon climate and (3) human activities that alter sedimentation within the deltaic system. Results reveal that the formation of deltaic sequences was initiated as a consequence of rapid sea-level rise between 9000 and 7000 cal. yr BP. The rate of sea-level rise slowed down markedly around 7000 cal. yr BP and sedimentation switched from transgressive to regressive. Initially, both the progradation of the delta plains near the apex and aggradation of delta front sedimentation in the central and lower parts of the receiving basin were fast owing to strong monsoonal-driven runoff. The progradation rate gradually slowed down between 6800 and 2000 cal. yr BP as monsoonal-driven runoff weakened. Rapid shoreline advances during the last 2000 years were the result of significantly increased human activities, a practice that trapped sediments in the encircled tidal flats along the front of delta plains. The evolutionary history of the Pearl River delta demonstrates the interplay between the three driving mechanisms.

Mid-Holocene variability of the East Asian monsoon based on bulk organic δ13C and C/N records from the Pearl River estuary, southern China

“…Results of this study are supported by other records, especially the highresolution stalagmite record from Dongge Cave (Wang et al, 2005). However, mismatches between millennial cycles from the δ (Zong et al, 2009a). Figure 2 Sediment input into the Pearl River estuary from three main sources including terrestrial, brackish-water and marine areas (adapted from Zong et al, 2006).…”

“…Before the Late Quaternary, sediment from the river system bypassed the current deltaic basin and was deposited on the continental slope and shelf (Zong et al, 2009a). Only since the Late Pleistocene has the deltaic basin started to receive sediments from the river system (Huang et al, 1982;Xu et al, 1985).…”

“…Only since the Late Pleistocene has the deltaic basin started to receive sediments from the river system (Huang et al, 1982;Xu et al, 1985). The lower fluvial/deltaic plains of Guangdong and Guangxi provinces have been gradually infilled during the Late Quaternary with progradation of the delta front since 6800 cal BP (Zong et al, 2009a; Figure 1b). …”

“…Thus, the influence of sea-level changes on the δ 13 C signal is assumed to be relatively minor. As a consequence of the stable sea level, the deltaic shoreline advanced slowly seawards between 6800 and 2000 cal yr BP (Figure 1b, Zong, et al, 2009a). Delta progradation during the mid-Holocene has led to core UV1 being more proximal to terrestrial source areas through time (Figure 1b).…”

Morphotectonics and evolutionary controls on the Pearl River Canyon system, South China Sea

“…Rising sea level, however, would reverse such depositional phenomena. Most of the terrestrial input would accumulate in the Pearl River Delta on the continental shelf and thalweg deposits would cease growing, as it does today (Zong et al 2009). …”