Sensitive grain-size records of Holocene East Asian summer monsoon in sediments of northern South China Sea slope

Abstract

Changes in paleoenvironments over the last 17,500 yr have been documented by a high-resolution clay mineralogy and grain–size records of Core KNG5 from the northern slope of the South China Sea. Our results indicate that clay minerals are mainly from the Pearl River from 17,500 to 12,500 cal yr BP, and the South China Sea modern current system began to form since 12,500 cal yr BP, as a result, Taiwan turns to be the major contributor of clay minerals after 12,500 cal yr BP. Two grain-size populations with high variability through time were identified in the 13–28 μm and 1–2.2 μm grain-size intervals. The 1–2.2 μm grain-size population are mainly controlled by provenance supply and current transport. The 13–28 μm grain-size fraction could be controlled mainly by the sea-level change. The 1–2.2 μm grain-size population record demonstrates that East Asian Summer Monsoon intensity generally follows changes in insolation and that the response is similar for a large area of China and other northern low-latitude records, implying the globality of the monsoon evolution since Holocene. The anomalous environmental conditions in the northern South China Sea may imply intensified ENSO activity during the late Holocene.

Sedimentary responses to the Indian Summer Monsoon variations recorded in the southeastern Andaman Sea slope since 26ka

“…Increased terrigenous MAR and mean grain-size were found during periods of low sea-level in the sea-level-dominated continental margin, such as northern and western South China Sea (Liu et al, 2005;Boulay et al, 2007;Huang et al, 2011). However, the increase in terrigenous MAR and mean grain-size noted here was found during the period of high sea-level, implying that sedimentation on the southeastern Andaman continental slope might be more related to monsoon intensification than to sea-level change.…”

“…Several mathematical methods have been developed to extract grain-size population; these methods primarily include end-member modeling (Prins et al, 2000) and grain-size versus standard deviation (Boulay et al, 2003). Sensitive grain size populations were extracted in this study using the method of grain-size versus standard deviation (Boulay et al, 2003); this method has been used to indicate marine sedimentary paleoenvironment and paleoclimate, as shown in several studies of the East China Sea (Xiao et al, 2006;Liu et al, 2010) and the South China Sea (Boulay et al, 2003;Liu et al, 2005;Huang et al, 2011). Standard deviations were calculated for 100 grain-size classes for each sample based on the grain size analysis.…”

Responses of the East Asian Summer Monsoon in the Low‐Latitude South China Sea to High‐Latitude Millennial‐Scale Climatic Changes During the Last Glaciation: Evidence From a High‐Resolution Clay Mineralogical Record

“…During the typical glacial-interglacial cycles, increase of illite and chlorite contents under reinforced physical erosion is considered to be associated with strengthened winter monsoon, while increase of smectite and kaolinite contents is related to intensive chemical weathering and then indicates strengthened summer monsoon (Liu et al, 2003(Liu et al, , 2004. Recently, clay mineralogical records have been demonstrated well displaying the H1 stadial occurred at around 16 ka BP in several northern SCS sediment cores Huang et al, 2011), implying that clay minerals could be used potentially as an efficient proxy to reflect the millennial-scale climate changes in the East Asian marginal seas. This mineralogical proxy has been realized by high-resolution paleoenvironmental studies in the Cariaco Basin, the Andaman Sea, and the Mediterranean Sea, indicating that clay mineralogy is sensitive enough to respond to interannual-to millennial-scale paleoenvironmental changes, such as interannual paleostorm activity, decadal lunar nodal tidal periodicity (16.8 yr), and millennial Intertropical Convergence Zone (ITCZ) shifts and monsoon variations (Ali et al, 2015;Black et al, 2009;Riboulleau et al, 2014;Sabatier et al, 2010).…”

An Integrated Sediment Mobility and Scour Assessment: Characterisation, Calibration and Mitigation Studies for a Pipeline in the South China Sea

“…During glacial periods, the South China Sea became a semi-restricted basin; the gateways to the Sulu Sea closed, the Sunda Shelf emerged and only the Bashi Strait was open to the Pacific Ocean (Huang et al, 2011;Wang, 1999). The Pearl River Mouth Basin was influenced by changes in climatic conditions throughout the Pleistocene and Holocene, which had a direct impact on the sediment deposition and the seafloor morphology.…”

“…The Pearl River Mouth Basin was influenced by changes in climatic conditions throughout the Pleistocene and Holocene, which had a direct impact on the sediment deposition and the seafloor morphology. The predominant clay mineral assemblage of river discharge in Taiwan is illite and chlorite with scarce smectite and kaolinite (Huang et al, 2011;Liu et al 2008). During glacial periods, the South China Sea became a semi-restricted basin; the gateways to the Sulu Sea closed, the Sunda Shelf emerged and only the Bashi Strait was open to the Pacific Ocean (Huang et al, 2011;Wang, 1999).…”