Modern variations in clay minerals in mud deposits of the Yellow and East China Seas and their geological significance

Abstract

The vertical distribution of clay minerals in the short cores B44, YSZD01, and DH8-1 collected from typical mud deposits in the North Yellow Sea, Central South Yellow Sea, and East China Sea and associated geological significances were examined based on the analysis of Pb²¹⁰ and Cs¹³⁷ dating, ratios of kaolinite/illite and smectite/chlorite, illite crystallinity, and illite chemical index. The sediments of mud deposits of the North Yellow Sea are mainly from the Yellow River (Huang He) with that of the inner East China Sea being mainly from the Yangtze River (Changjiang), while sediment sources of mud deposits of the Central South Yellow Sea mainly include the Yellow River and the old Yellow River delta. For cores B44 and DH8-1 with a single main source, both illite chemical index and illite crystallinity have a close relationship with temperature and precipitation in the sediment-source river basin except for YSZD01 with a multi-source. Generally, the ratios of kaolinite/illite and smectite/chlorite indicate that chemical weathering strengthens while physical weathering weakens within the source river basin for the mud sediments from the North Yellow Sea to the Central South Yellow Sea to the East China Sea. In general, illite percentage would decrease, while kaolinite percentage would increase for cores B44, YSZD01, and DH8-1 if the East Asian Winter Monsoon was enhanced in the past 100 years.

Keywords

clay mineral East Asian Winter Monsoon East China Sea provenance weathering Yellow Sea

Introduction

Epicontinental seas of East China, as the open edges of the Western Pacific, are sensitive to the factors of land–ocean interactions, such as terrestrial rivers, the East Asian Monsoon, and ocean circulation. Massive terrestrial materials were input into the Yellow Sea and East China Sea during the Holocene, forming several large mud deposits, which are regarded as suitable paleoenvironment information carriers. Clay minerals in these muddy sediments are very useful for interpreting a number of issues such as provenance identification, sediment transport, climatic change, and oceanic circulation evolution (Liu, 1987; Liu et al., 2006; Wang et al., 2015a; Xu et al., 2009; Yang et al., 2003; Zhu et al., 1988). Main clay minerals in mud deposits on the continental shelf of East China include smectite, illite, kaolinite, and chlorite. In general, smectite forms easily in the area which is rich in alkalis, alkaline earth metal, and hydroxide ion (Tang et al., 2002). Illite exists in the environment with slightly lower temperature and alkalescence. Kaolinite is formed by strong leaching of rocks under humid climate condition (Tang et al., 2002). Chlorite exists in regions such as glaciers and arid areas where chemical weathering is weak (Rateer et al., 1969). In the mud deposits of the continental shelf of East China, smectite content decreases from north to south and increases from coast to seaward. Conversely, kaolinite content increases from north to south and decreases from coast to seaward. Chlorite and illite contents increase from coast to seaward (Li, 1990). The variation of clay mineral distribution is attributed to provenance, climate, circulation, and clay mineral characteristics.

During the past several decades, a lot of work on clay minerals in mud deposits of continental shelf of East China has been done (Dou et al., 2014; Li et al., 2014; Liu et al., 2010, 2012, 2014; Wan et al., 2010; Wang et al., 2015b). However, most of the previous studies were more focused on surface sediments than core sediments, and mainly on the provenance identification and sediment transport mechanism (Dou et al., 2014; Li et al., 2014; Liu et al., 2010; Wang et al., 2015b). Moreover, previous studies on sedimentary record with cores have often a millennial, centurial, or decadal timescale, and few are on a yearly timescale. There are few comparisons among sedimentary records with cores from different muddy areas covering a short timescale. In addition, sediment discharge of nearby rivers on the continental shelf of East China has decreased dramatically in recent decades, which is of importance to interannual variation of clay minerals (Wang et al., 2015a, 2015b; Zhou et al., 2010). The aim of this study is to examine the variations in high-resolution sedimentary records about climate features of sediment-source basin and the East Asian Winter Monsoon in the last century by investigating the clay mineral content of three cores collected from mud deposits in the North Yellow Sea, Central South Yellow Sea, and East China Sea, respectively.

Geographical setting

The Yellow Sea, a typical semi-enclosed epicontinental sea surrounded by Liaodong, Shandong, and Korean peninsulas, rests on a flat, broad, and tectonically stable seafloor with a water depth of average 55 m and a maximum of 100 m (Yang et al., 2003). The Yellow Sea, separated from the Bohai Sea at its northern extremity by the Shandong and Liaodong peninsulas and their extension cord and from the East China Sea to the south by an arbitrary line connecting the north of the Yangtze River mouth with Cheju Island, occupies a total area of about 400,000 km² (Mei et al., 2016; Yang et al., 2003). It has received massive terrestrial materials during the Holocene, forming large mud deposits in the North Yellow Sea and Central South Yellow Sea (Figure 1). The Yellow Sea is characterized by complex hydrodynamic conditions (Figure 1). In addition to tidal effects, two surface oceanic circulations occur, the Yellow Sea Warm Current and the Yellow Sea Coastal Current.

Figure 1.

Schematic map of the Yellow Sea and East China Sea and the locations of cores in the muddy deposits.

The East China Sea with a wide flat shelf is an open epicontinental sea of the Western Pacific (Figure 1). The mud deposits are located off the Yangtze River estuary and Zhemin Coast and in the southwest of Cheju Island. During the Holocene, the mud deposits have formed on the shelves of the East China Sea in a response to low-energy, shelf depositional environments dominated by the coastal currents and a condition of higher sea levels after transgression since the last glacial period (Liu et al., 2014; Xu et al., 2009). The mud wedge of Zhemin Coast, which is located on the inner shelf of the East China Sea, stretches from the subaqueous delta of the Yangtze River southward to the Taiwan Strait, with the maximum thickness of about 40 m (Liu et al., 2007). The oceanography of the inner shelf of East China Sea is dominated by the southward-flowing Zhemin Coastal Current and northward-flowing Taiwan Warm Current (Figure 1; Liu et al., 2006).

Materials and methods

Cores B44, YSZD01, and DH8-1 were collected using a gravity box sampler by the vessels of Dongfanghong 2 in 2010, Runhong in 2012, and Kesan in 2012, respectively. More information about the three cores is listed in Table 1.

Table 1.

The information about cores B44, YSZD01, and DH8-1.

Cores	Locations	Latitude (°N)	Longitude (°E)	Length (cm)	Water depth (m)
B44	North Yellow Sea	38	122.5	48	50
YSZD01	Central South Yellow Sea	35.72	123.20	28	73
DH8-1	East China Sea	26.77	120.83	43	51

The three cores were sampled at an interval of 0.5 cm for clay mineral measurement. All samples were pretreated to remove carbonate with distilled water and 0.25 mol/L HCl and organic matters with 30% H₂O₂. Then, 5 mol/L (NaPO₃)₆ was used to disperse sediment samples, and the sediment sample stood for more than 24 h. The sample was then placed into an ultrasonic disperser and vibrated for 10–15 min (Miao et al., 2016). Finally, the particles smaller than 2 µm were extracted based on Stoke’s law, and the ethylene glycol–saturated oriented slide (EG) was made.

Clay mineral measurement was carried out at the Ocean University of China, using a D/max-RB x-ray diffractometer with a Cukα radiation (40 kV, 100 mA), a scanning speed of 5°/min, a sweep range of 3–33° (2θ), and a step size of 0.02°/s. The fitting of x-ray diffraction (XRD) curves, along with the calculation of intensity value of peaks, was finished using MDI Jade software version 5.0. Semi-quantitative calculations of peak areas for smectite (17 Å), illite (10 Å), and kaolinite and chlorite (7 Å) were performed according to the Biscaye (1965) method. The empirical factors of smectite, illite, and sum of kaolinite and chlorite were 1:4:2. The sum of all four clay minerals was fixed at 100%. The percentage of kaolinite and chlorite was obtained by subdividing the 7Å peak area according to the ratio of 3.58Å (kaolinite) to 3.54Å (chlorite) peaks. Illite crystallinity was estimated with the full width half maximum (FWHM) of illite d₀₀₁ (1.0 nm) peak. In general, narrow and symmetrical diffraction peaks of illite indicate a high illite crystallinity (Yang, 1993). The lower value of FWHM means higher illite crystallinity and weaker chemical weathering (He et al., 2011; Krumm and Buggisch, 1991). The ratio of the 5Å to 10Å illite peaks is referred to as illite chemical index, with a ratio of <0.5 indicating the illite rich in Fe-Mg, formed under a strong physical weathering condition, and a ratio of >0.5 indicating the illite rich in Al, formed under a strong chemical weathering condition (Gingele, 1996). The illite chemical index has been widely used to indicate the provenance and climate change (e.g. Liu et al., 2003; Wan et al., 2008).

The Pb²¹⁰ and Cs¹³⁷ dating of cores B44, YSZD01, and DH8-1 was conducted with a γ spectrometer, showing a deposition period and yearly deposition rates of 97 years and 0.49 cm/yr, 110 years and 0.21 cm/yr, and 62 years and 0.69 cm/yr, respectively. Generally, the sedimentary record with sediment sampling at an interval of 0.5 cm has been proven to be able to show yearly changes in environment (Miao et al., 2016; Shen et al., 2015).

Results

The clay minerals in cores B44, YSZD01, and DH8-1 include illite, kaolinite, chlorite, and smectite. The statistics of clay minerals in these three cores are listed in Table 2.

Table 2.

Statistics of clay mineral percentages, their ratios, illite chemical index (CI), and illite crystallinity (FWHM) in cores B44, YSZD01, and DH8-1 of mud deposits in the Yellow Sea and East China Sea.

Core	Items	Percentage					FWHM	CI	Ratios
Core	Items	S	I	K	C	I + C	FWHM	CI	I/S	C/K	K/I	S/K	S/C
B44	Maximum	22.7	73.3	22.7	15.8	85.4	0.64	0.73	35.43	1.66	0.33	2.67	3.63
	Minimum	1.9	60.5	8.5	4.2	67.1	0.35	0.13	2.67	0.19	0.14	0.10	0.13
	Average	5.5	68.7	14.8	11.1	79.8	0.54	0.48	15.17	0.81	0.21	0.41	0.55
	SD	3.5	2.1	3.1	2.8	3.6	0.04	0.10	5.54	0.31	0.05	0.37	0.53
YSZD01	Maximum	6.9	72.4	17.9	14.3	84.4	0.56	0.71	98	1.01	0.26	0.45	0.60
	Minimum	0.7	65.8	14.2	8.8	77.6	0.41	0.45	9.53	0.49	0.20	0.04	0.06
	Average	3.3	69.4	15.9	11.4	80.8	0.53	0.61	25.50	0.72	0.23	0.21	0.30
	SD	1.2	1.1	1.1	1.2	0.1	0.03	0.05	15.65	0.11	0.02	0.08	0.13
DH8-1	Maximum	4.3	73.8	24.2	17.7	91.4	0.59	1.12	106.00	2.41	0.36	0.31	0.64
	Minimum	0.7	66.1	7.3	4.9	72.7	0.37	0.17	16.00	0.20	0.10	0.03	0.06
	Average	2.6	69.2	17.2	11.0	80.2	0.53	0.57	31.99	0.67	0.25	0.15	0.25
	SD	0.9	1.6	2.2	1.9	2.5	0.02	0.16	17.39	0.26	0.03	0.05	0.11

S: smectite; I: illite; K: kaolinite; C: chlorite; I + C: illite + chlorite; FWHM: full width half maximum; CI: illite chemical index; I/S, C/K, K/I, S/K, and S/C: ratios of illite/smectite, chlorite/kaolinite, kaolinite/illite, smectite/kaolinite, and smectite/chlorite; SD: standard deviation.

Core B44 in North Yellow Sea

For individual clay mineral in core B44, the highest average percentage is 68.7% for illite, contrasting with the lowest of 5.5% for smectite (Table 2). The average percentage of kaolinite and chlorite is 14.8% and 11.1%, respectively. The vertical changes in percentage composite of smectite and illite in core B44 are opposite (Figure 2a). In general, the percentage of kaolinite first decreases and then increases from upward, while that of chlorite has the opposite trend. The vertical changes in percentage composite of kaolinite and illite are opposite. Ratios of smectite/chlorite and smectite/kaolinite similarly change. The illite crystallinity with an average of 0.54°Δ2θ and the illite chemical index with an average of 0.48 have a similar vertical trend through core B44.

Figure 2.

The down-core distributions of clay mineral contents, their ratios, CI, and FWHM in (a) core B44 in the North Yellow Sea, (b) core YSZD01 in the Central South Yellow Sea, and (c) core DH8-1 in the East China Sea.

Core YSZD01 in Central South Yellow Sea

The dominant clay mineral in core YSZD01 is illite with an average of 69.4%, followed by kaolinite (15.9%), chlorite (11.4%), and smectite (3.3%) (Table 2). The percentage composite of smectite and illite has an opposite tendency (Figure 2b). The vertical changes in percentage composite of kaolinite and illite are opposite. The content of chlorite, sum of illite and chlorite, ratio of illite/smectite, and ratio of chlorite/kaolinite have a similar changing trend. There is no similar tendency for illite crystallinity with an average of 0.53°Δ2θ and illite chemical index with an average of 0.61 through core YSZD01.

Core DH8-1 in East China Sea

The dominant component of clay minerals in core DH8-1 is illite with an average of 69.2%, followed by kaolinite (17.2%), chlorite (11.0%), and smectite (2.6%) (Table 2). The smectite content in core DH8-1 has a decreasing–increasing–decreasing trend from bottom to top, while illite has the opposite trend (Figure 2c). Generally, the percentage curves of kaolinite and chlorite are opposite. The kaolinite content and illite content change in opposite tendency. Chlorite, sum of chlorite and illite, and ratio of chlorite/kaolinite have similar changing curves. Ratio of smectite/kaolinite and ratio of smectite/chlorite have a similar trend. The vertical curves of illite crystallinity and illite chemical index, with averages of 0.53°Δ2θ and 0.57, respectively, are similar at the bottom of the core, but opposite in the upper part of the sequence.

Discussion

Sediment provenance

Terrigenous clay minerals experience processes of migrating, diffusing, and flocculating during the transport from land to ocean. Nevertheless, the essential feature of clay minerals does not change because of their resistance to corrosion (He and Liu, 1997; Riley and Chester, 1976), which is widely used to determine the sediment provenance (Dou et al., 2014; Li et al., 2014; Liu et al., 2010; Wang et al., 2015a). In this study, the clay mineral percentage data of the Yangtze and Yellow rivers and deltas were collected and a ternary diagram was used to determine the sediment provenance of cores B44, YSZD01, and DH8-1 (Chen et al., 2010; Ren and Shi, 1986; Xu, 1983; Yang et al., 2003; Figure 3).

Figure 3.

Ternary diagram of percentage composition of illite + chlorite, kaolinite, and smectite in cores B44, YSZD01, and DH8-1 in mud deposits of the Yellow Sea and the East China Sea. The data of the Yangtze and Yellow rivers and deltas are compiled from Yang et al. (2003), Ren and Shi (1986), Xu (1983), and Chen et al. (2010).

On one hand, the clay minerals of all the three cores from the mud deposits of North Yellow Sea, Central South Yellow Sea, and Zhemin Coast include illite, kaolinite, chlorite, and smectite in a decreasing order of percentages, that is, 68.7%, 14.7%, 11.1%, and 5.5% for core B44 (Table 2; Figure 2). On the other hand, the percentages of clay minerals vary among the three cores. For smectite, the highest average percentage is 5.5% for core B44, contrasting with the lowest of 2.6% for core DH8-1, while the kaolinite percentage of core B44 is lower than that of core DH8-1. It is reported that the smectite percentage of the Yellow River material is significantly higher than that of the Yangtze River, but the kaolinite percentage is lower than that of the Yangtze River (Fan et al., 2001). Besides, as Figure 3 shows, the clay mineral assemblage of core B44 has a broad distribution area which is similar to that of the Yellow River and delta, while the clay mineral assemblages of core DH8-1 and the Yangtze River and delta have a similar distribution range. Therefore, it is suggested that sediments of core B44 from mud deposit of the North Yellow Sea are mainly from the Yellow River, whereas those of core DH8-1 from the mud deposit Zhemin Coast are mainly from the Yangtze River, which is consistent with previous studies (Fan et al., 2001; Qi et al., 2004). The percentages of smectite and kaolinite of core YSZD01 are between core B44 and core DH8-1 (Table 2). Correspondingly, the assemblage distribution of clay minerals of core YSZD01 in the ternary diagram is mainly between core B44 and core DH8-1 (Figure 3). Therefore, sediment materials of core YSZD01 from the mud deposit of Central South Yellow Sea are mainly from the Yellow River and the old Yellow River delta and partly from the Yangtze River, which is consistent with previous studies (Lan et al., 2005, 2011; Li et al., 1999, 2006; Yang et al., 1992; Zhao et al., 1991).

Climatic features of sediment-source river basin

Smectite easily forms in alternately dry–wet environments, while kaolinite exists in warm and moist environments. With the increase in temperature and rainfall, smectite is easily converted into kaolinite (Liang et al., 2015). As a result, when smectite content decreases, kaolinite content increases. The ratio of kaolinite/illite and ratio of smectite/chlorite have been used to examine the provenance and regional climatic change (Liang et al., 2015). The higher value of smectite/chlorite ratio, together with the lower value of kaolinite/illite ratio, means stronger physical weathering and weaker chemical weathering. Conversely, the higher value of kaolinite/illite ratio, together with the lower value of smectite/chlorite ratio, means stronger chemical weathering and weaker physical weathering (Liang et al., 2015; Wan et al., 2008). The ratio of smectite/chlorite has a decreasing tendency in cores B44 of North Yellow Sea, YSZD01 of Central South Yellow Sea, and DH8-1 of East China Sea, while the ratio of kaolinite/illite has a roughly opposite tendency (Figure 4). Generally, chemical weathering strengthens while physical weathering weakens within the source river basin for the mud sediments from the North Yellow Sea to the Central South Yellow Sea to the East China Sea (Figure 4).

Figure 4.

Clay mineral ratios indicating different provenance and weathering regimes of cores B44, YSZD01, and DH8-1 in mud deposits of the Yellow Sea and the East China Sea.

In order to further explore how clay minerals of cores B44, YSZD01, and DH8-1 indicate the climatic features of the sediment-source basins, the temperature and precipitation data of the Yellow River drainage and the Yangtze River drainage were collected from 104 and 115 meteorological stations, respectively, which cover the whole river basins (Chen, 2007; Yao and Wu, 2014). As the climate of the Yellow River basin is gradually getting warmer, the average temperature has been on the rise since the middle of the 20th century (Figure 5). The illite chemical index and the illite crystallinity of core B44 in North Yellow Sea show a similar tendency with the precipitation of the Yellow River basin (Figure 5). For core YSZD01 in Central South Yellow Sea, a multi-source depocenter, there is no similar tendency of illite crystallinity and chemical index with temperature and precipitation in the Yellow River basin (Figure 5). The illite chemical index and the illite crystallinity of core DH8-1 correlate well with the climatic features of the Yangtze River basin (Figure 6). In fact, precipitation and temperature are important factors influencing the physical and chemical weathering (Ludwig and Probst, 1998; Pinet and Souriau, 1988). Higher precipitation and temperature mean stronger chemical weathering (White and Blum, 1995). Therefore, the illite crystallinity and illite chemical index of core B44 in North Yellow Sea and core DH8-1 in the inner East China Sea indicate the climatic features and physical and chemical weathering.

Figure 5.

Variations in illite chemical index and illite crystallinity in cores B44 and YSZD01 in mud deposits of the Yellow Sea and the East China Sea. The data of annual temperature and precipitation in the Yellow River drainage basin are mainly from Yao and Wu (2014). Thick line in each panel denotes a 5-point running average. Vertical thick gray lines help to observe relationships.

Figure 6.

Variations in chemical index and illite crystallinity in core DH8-1 in the East China Sea. The data of annual temperature and precipitation in the Yangtze River drainage basin are mainly from Chen (2007). Thick line in each panel denotes 5-point running average. Vertical thick gray line helps to observe relationship.

The East Asian Winter Monsoon

Characteristics of clay minerals are often affected by the sediment-source and transportation mechanism (Guo et al., 2000; Liu et al., 2006; Yang et al., 2012). The sedimentation of clay minerals in mud deposits is affected by coastal currents, which are mainly controlled by the East Asian Winter Monsoon (Clift, 2016; Wang et al., 2015a). If the East Asian Winter Monsoon intensifies, the illite percentage decreases and kaolinite percentage increases because of various features of clay minerals – that illite is scaly and flake and deposits easily under quieter environment, while kaolinite is granular and platy and deposits easily under relatively strong condition (Figure 7; Li, 1990). Compared with summer monsoon, the winter monsoon has a much more crucial control on the sediment materials along the coastal areas (Wang et al., 2015a). However, summer monsoon also has an influence on the sedimentation process and grain size (Wang and Li, 2014; Wang et al., 2008). In short, clay minerals in muddy deposits in the Yellow Sea and East China Sea could indicate the change of winter monsoon.

Figure 7.

Variations in kaolinite and illite contents in cores B44, YSZD01, and DH8-1 located in mud deposits of the Yellow Sea and the East China Sea. The data of the strength of the East Asian monsoon are from Shi and Zhu (2000), He and Wang (2012), and Yang et al. (2011). Thick line denotes a 5-point running average.

From sources to sinks in the marginal seas, terrigenous clay minerals experience processes of generating, migrating, transporting, and deposition by complicated physical and chemical processes, which are roughly illustrated in Figure 8. Clay minerals in the muddy sediments provide a useful tool for interpreting important features such as the evolution of the East Asian Winter Monsoon, climate conditions in source regions, and provenance identification.

Figure 8.

Schematic diagram of clay mineral formation, transportation, and deposition processes indicating that multi-factors could affect clay minerals in the mud deposits of the Yellow Sea and the East China Sea (after Alizai et al., 2012).

The high-resolution sampling at an interval of 0.5 cm for mineral clay measurement in our study is very close to the yearly deposition rate of the three cores (0.49 cm/yr for B44, 0.21 cm/yr for YSZD01, and 0.69 cm/yr for DH8-1). In general, the sedimentary record could roughly indicate yearly changes. In this study, sources of error include reworking of older material, human activities such as agriculture (Hu et al., 2013; Yang and Zhang, 2010), topography, and vegetation of river valleys (Huang et al., 2015); however, even collectively, these were not thought to constitute a significant source of overall error relative to the goals of the project. In fact, we can see clear variations in the identification of sediment provenance (Figure 3), chemical and physical weathering (Figure 4), climatic change (Figures 5 and 6), and the East Asian Monsoon (Figure 7).

Conclusion

Based on the measurement and analysis of clay minerals in cores B44, YSZD01, and DH8-1 in mud deposits in the North Yellow Sea, Central South Yellow Sea, and East China Sea, together with Pb²¹⁰ and Cs¹³⁷ dating, the vertical distributions of clay minerals are presented and geological significance is discussed. The main conclusions are drawn in the following.

The clay minerals of all three cores include illite, kaolinite, chlorite, and smectite in a decreasing order of percentage. The percentage of smectite has a decreasing tendency among mud deposits from North Yellow Sea to Central South Yellow Sea to Zhemin Coast, while that of kaolinite has an opposite tendency.

The main sediment sources are the Yellow River for core B44 in the North Yellow Sea and the Yangtze for core DH8-1 in the East China Sea, while core YSZD01 in Central South Yellow Sea receives sediment inputs from the Yellow River, the old Yellow River delta, and the Yangtze.

Generally, the ratios of kaolinite/illite and smectite/chlorite indicate that chemical weathering strengthens and physical weathering weakens in the sediment-source environment from core B44 to core YSZD01 to core DH8-1. Both illite chemical index and illite crystallinity have a close relationship with temperature and precipitation in the sediment-source river basin except for YSZD01 with a multi-source. In general, illite percentage decreased and kaolinite percentage increased for cores B44, YSZD01, and DH8-1 when the East Asian Winter Monsoon enhanced in the past 100 years.

In summary, this research further proves that clay minerals of mud deposits in the Yellow Sea and East China Sea can be used to reconstruct East Asian Winter Monsoon as well as climate conditions in the source regions and to locate sediment provenances.

Footnotes

Acknowledgements

The authors thank Editor Fabienne Marret and two anonymous reviewers for constructive comments.

Funding

This work was supported by the National Natural Science Foundation of China (no. 41376052).

References

Alizai

Hillier

Clift

et al . (2012) Clay mineral variations in Holocene terrestrial sediments from the Indus Basin. Quaternary Research 77: 368–381.

Biscaye

(1965) Mineralogy and sedimentation of recent deep-sea clay in the Atlantic Ocean and adjacent seas and oceans. Geological Society of America Bulletin 76: 803–832.

Chen

(2007) Analysis of meteorological elements and study on the reason of the variation evaporation in Changjiang River basin in recent 50a. Master’s Thesis, Nanjing: Hohai University, pp. 1–113 (in Chinese).

Chen

Zhou

(2010) Clay minerals in the major Chinese coastal estuaries and their provenance implications. Frontiers of Earth Science in China 4: 449–456.

Clift

(2016) Assessing effective provenance methods for fluvial sediment in the South China Sea. In: Clift

Harff

et al . (eds) River-Dominated Shelf Sediments of East Asian Seas. London: Geological Society of London (Special Publication 429), pp. 9–29.

Dou

Zhao

et al . (2014) Clay mineral distributions in surface sediments of the Liaodong Bay, Bohai Sea and surrounding river sediments: Sources and transport patterns. Continental Shelf Research 73: 72–82.

Fan

Yang

Mao

et al . (2001) Clay minerals and geochemistry of the sediments from the Yangtze and Yellow Rivers. Marine Geology & Quaternary Geology 21: 7–12 (in Chinese).

Gingele

(1996) Holocene climatic optimum in Southwest Africa-evidence from marine. Palaeogeography, Palaeoclimatology, Palaeoecology 122: 77–87.

Guo

Yang

et al . (2000) Study on the comparison sedimentary geochemistry of mud area on East China Sea Continental Shelf. Acta Sedimentologica Sinica 18: 284–289 (in Chinese).

10.

Liu

(1997) Chemical characteristics of clay minerals of Yangtze and Yellow Rivers. Chinese Science Bulletin 42: 730–733 (in Chinese).

11.

Zheng

Huang

et al . (2011) Clay minerals assemblages in the Yangtze drainage and provenance implications. Acta Sedimentologica Sinica 29: 544–551 (in Chinese).

12.

Wang

(2012) An integrated East Asian winter monsoon index and its interannual variability. Chinese Journal of Atmosphere Sciences 36: 523–538 (in Chinese).

13.

Clift

Böning

et al . (2013) Holocene evolution in weathering and erosion patterns in the Pearl River delta. Geochemistry, Geophysics, Geosystems 14: 2349–2368.

14.

Huang

Liu

Chetelat

et al . (2015) Seasonal variation characteristics of weathering in the three rivers basin, southern western China. Earth and Environment 43: 512–521 (in Chinese).

15.

Krumm

Buggisch

(1991) Sample preparation effects on illite crystallinity measurements: Grain size gradation and particle orientation. Journal of Metamorphic Geology 9: 671–677.

16.

Lan

Zhang

(2005) Material sources and transportation of sediments in the southern Yellow Sea. Transactions of Oceanology and Limnology 4: 53–60 (in Chinese).

17.

Lan

Zhang

Liu

(2011) Distribution pattern of clay minerals in surface sediments of south Yellow Sea and their provenance. Marine Geology & Quaternary Geology 31: 11–16 (in Chinese).

18.

Yang

et al . (1999) Discussion on sedimentation rates material source in the east part of the South Yellow Sea. Marine Science 5: 37–40 (in Chinese).

19.

(1990) Composition, distribution and geology significance of clay mineral in surface sediments in China Sea. Acta Oceanologica Sinica 12: 470–479 (in Chinese).

20.

Huang

et al . (2014) Clay minerals in surface sediment of the north Yellow Sea and their implication to provenance and transportation. Continental Shelf Research 90: 33–40.

21.

Liang

Yang

Yin

et al . (2015) Distribution of clay mineral assemblages in the rivers entering Yellow Sea and East China Sea and the muddy shelve deposits and control factors. Marine Geology & Quaternary Geology 35: 1–15 (in Chinese).

22.

Liu

(1987) Study of the relationship between characteristics of clay minerals and depositional environments. Acta Sedimentologica Sinica 5: 48–57 (in Chinese).

23.

Liu

Yan

Chen

et al . (2012) Sediment sources and their contribution along northern coast of the South China Sea: Evidence from clay minerals of surface sediments. Continental Shelf Research 47: 156–164.

24.

Liu

et al . (2006) Sedimentary features of the Yangtze River-derived along-shelf clinoform deposit in the East China Sea. Continental Shelf Research 26: 2141–2156.

25.

Liu

et al . (2007) Flux and fate of Yangtze River sediment delivered to the East China Sea. Geomorphology 85(3–4): 208–224.

26.

Liu

Shi

Fang

et al . (2014) Spatial and temporal distributions of clay minerals in mud deposits on the inner shelf of the East China Sea: Implications for paleoenvironmental changes in the Holocene. Quaternary International 349: 270–279.

27.

Liu

Colin

et al . (2010) Clay mineral distribution in surface sediments of the northeastern South China Sea and surrounding fluvial drainage basins: Source and transport. Marine Geology 277: 48–60.

28.

Liu

Trentesaux

Clemens

et al . (2003) Clay mineral assemblages in the northern South China Sea: Implications for East Asian monsoon evolution over the past 2 million years. Marine Geology 201: 133–146.

29.

Ludwig

Probst

(1998) River sediment discharge to the ocean: Present-day controls and global budgets. American Journal of Science 298: 265–295.

30.

Mei

Zhang

et al . (2016) Evolution of the Yellow Sea warm current and the Yellow Sea cold water mass since the Middle Pleistocene. Palaeogeography, Palaeoclimatology, Palaeoecology 442: 48–60.

31.

Miao

Chu

(2016) Three Gorges Dam controls sediment coarsening of the mud patch on the Inner East China Sea shelf. Journal of Ocean University of China (Oceanic and Coastal Sea Research) 15: 414–422.

32.

Pinet

Souriau

(1988) Continental erosion and large-scale relief. Tectonics 7: 563–582.

33.

Song

et al . (2004) Sedimentation rate and the flux of the North Yellow Sea. Marine Geology & Quaternary Geology 24: 9–14 (in Chinese).

34.

Rateer

Gorbunova

Lisitzyn

et al . (1969) The distribution of clay minerals in the ocean. Sedimentology 13: 21–43.

35.

Ren

Shi

(1986) Sediment discharge of the Yellow River (China) and its effect on the sedimentation of the Bohai and the Yellow Sea. Continental Shelf Research 6: 785–810.

36.

Riley

Chester

(1976) Chemical Oceanography, vol. 5. London: Academic Press, pp. 112–115.

37.

Shen

Chu

Wang

et al . (2015) Sensitive grain size and its environmental significance of modern mud patches in southern and northern parts of the Yellow Sea. Acta Sedimentologica Sinica 33: 124–133 (in Chinese).

38.

Shi

Zhu

(2000) East Asian summer winter monsoon index for 1873–1995. Meteorological Science 3: 14–18 (in Chinese).

39.

Tang

Jia

Xie

(2002) Environment significance of clay minerals. Earth Science Frontiers 9: 337–344 (in Chinese).

40.

Wan

et al . (2008) Characteristics of clay minerals in the northern South China Sea and its implications for evolution of East Asian Monsoon since Miocene. Journal of China University of Geosciences 19: 23–37.

41.

Wan

Tian

Steinke

et al . (2010) Evolution and variability of the East Asian summer monsoon during the Pliocene: Evidence from clay mineral records of the South China Sea. Palaeogeography, Palaeoclimatology, Palaeoecology 293: 237–247.

42.

Wang

et al . (2015a) Clay mineral and grain size studies of sediment provenances and paleoenvironment evolution in the middle Okinawa Trough since 17ka. Marine Geology 366: 49–61.

43.

Wang

Zheng

et al . (2008) High-resolution paleoenvironmental record of the mud sediments of the East China Sea inner shelf. Marine Geology & Quaternary Geology 28: 1–10.

44.

Wang

(2014) High-resolution sedimentary records of the muddy area in the South Yellow Sea and East China Sea: A review of new progress. Marine Geology & Quaternary Geology 34: 167–174.

45.

Wang

Fan

et al . (2015b) The variation of clay minerals contents of inner shelf of the East China Sea in the last one hundred years and its environmental implication. Acta Oceanologica Sinica 37: 87–100 (in Chinese).

46.

White

Blum

(1995) Effects of climate on chemical weathering in watersheds. Geochimica et Cosmochimica Acta 59: 1729–1747.

47.

(1983) Mud sedimentation on the East China Sea shelf. In: Proceedings of International Symposium on Sedimentation on the Continental Shelf with Special Reference to the East China Sea, Hangzhou, 12–16 April, pp. 506–516. Beijing: China Ocean Press.

48.

Million

et al . (2009) Yangtze-and Taiwan-derived sediments on the inner shelf of East China Sea. Continental Shelf Research 29: 2240–2256.

49.

Yang

Zhi

Gao

(2011) Variation of East Asian Summer monsoon and its relationship with precipitation over China in recent 111 years. Journal of Anhui Agricultural Sciences 39: 2007–2011 (in Chinese).

50.

Yang

Zhang

(2010) Soil weathering rates and its implications: A review. Soils 42: 882–888 (in Chinese).

51.

Yang

Jung

Lim

et al . (2003) A review on the provenance discrimination of sediments in the Yellow Sea. Earth Science Review 63: 93–120.

52.

Yang

Feng

Chu

et al . (2012) Surface sediment distribution and sedimentary environment on the East China Continental Shelf. Periodical of Ocean University of China 42: 126–134 (in Chinese).

53.

Yang

(1993) Illite crystallinity and its geological significances. Acta Sedimentologica Sinica 11: 92–98 (in Chinese).

54.

Yang

Guo

Wang

et al . (1992) The transport pattern of suspended material from the continental self of Yellow and East China Seas to the deep ocean. Acta Oceanologica Sinica 14: 81–90.

55.

Yao

(2014) Characteristics and variation trends of temperature and precipitation in the Yellow River basin during 1961–2010. China Rural Water and Hydropower 8: 104–114 (in Chinese).

56.

Zhao

Qin

et al . (1991) Source and genesis of mud in the central part of the South Yellow Sea in special reference to geochemical data. Geochemica 2: 112–117.

57.

Zhou

Wan

et al . (2010) Clay minerals in surfacial sediments of the East China Sea shelf: Distribution and provenance. Oceanologia et Limnologia Sinica 41: 667–675 (in Chinese).

58.

Zhu

Gao

(1988) Research of clay minerals of sediments on the continental shelf of the East China. Donghai Marine Science 6: 40–51 (in Chinese).