Quaternary sea-level change on the continental shelf of Hong Kong

Abstract

High-resolution seismic reflection profiles and continuously sampled boreholes have been used to investigate the Quaternary offshore sequence that overlies weathered bedrock in Hong Kong. Four formations have been recognized: the lowermost Chek Lap Kok Formation comprises dominantly fluvial sand and mud, much of which probably accumulated prior to 130 000 years BP, during sea-level lowstands of Middle Pleistocene (Oxygen Isotope Stage 6) age and earlier. The upper surface of the Chek Lap Kok Formation is defined by a fluvial/tidal entrenchment surface that is overlain by transgressive, fine-grained, marine sediments of the Sham Wat Formation. These were deposited during the Eemian interglacial (Stage 5c) at a time when sea level was similar to that of today. In southeastern Hong Kong waters, a late Weichselian (Stage 5c) ravinement surface is overlain by submerged shoreface sands, succeeded by a back-stepping wedge of marine sediments that comprise the Waglan Formation. Fluvial/tidal entrenchment of the top of this formation occurred prior to the deposition of the uppermost dominantly marine Hang Hau Formation, deposited during the Late Weichselian to Holocene transgression, the main phase of which is represented by a ravinement surface.

A new regional, mid-Holocene palaeoprecipitation signal of the Asian Summer Monsoon

“…Values are generally high across the delta front, ranging from 0.65 to 0.99, but decrease dramatically across the delta front -pro-delta transition (0.79-0.30, Fig. 1b) probably reflecting the lower, distal sedimentation rates (Fyfe et al, 1997;Zong et al, 2009). The core is located on the pro-delta area (Fig.…”

Recent geomorphic change in LingDing Bay, China, in response to economic and urban growth on the Pearl River Delta, Southern China

“…In 1980 the PRD's population was primarily agricultural and rural, only about 16% of the population being considered urban. Between 1989 and1997, in response to the economic expansion, cropland decreased by 48% in area, matched by a similar increase of urban area (Weng, 2007). At present, about 80% of the 55 million people inhabiting the delta (www.ucer.camcom.it) are considered urban, and the number of cities on the delta has increased from 3 to 23 (Shen et al, 2006).…”

“…The seaward-most 30-60 km of the delta have accreted over the last several millennia due to falling sea level (Fyfe et al, 1997;Fyfe et al, 1999;Hanebuth et al, 2000), and, during the past 1000 years, due to land reclamation during the Tang, Song and Qing dynasties (Zheng et al, 2004;Zong et al, 2009, their Fig. 5).…”

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

“…The particle size and diatom results from the 77 surface sediment samples are shown in Figure 2 and summarized in Table 2. These samples are grouped according to the delta plain, delta front, prodelta environments and a non-deltaic marine environment, as defined by Fyfe et al (1997) and adopted by Fyfe et al (1999) and Owen (2005).…”