Sedimentary Budget of the Northwest Sub-Basin, South China Sea: Controlling Factors and Geological Implications

Louisiana State University LSU Digital Commons

Faculty Publications Department of Geology and Geophysics

4-1-2019

Sedimentary budget of the Northwest Sub-basin, South China Sea: controlling factors and geological implications

Peter D. Clift Louisiana State Univ, Dept Geol & Geophys, [email protected]

Follow this and additional works at: https://digitalcommons.lsu.edu/geo_pubs

Part of the Geology Commons

Recommended Citation Clift, Peter D., "Sedimentary budget of the Northwest Sub-basin, South China Sea: controlling factors and geological implications" (2019). Faculty Publications. 8. https://digitalcommons.lsu.edu/geo_pubs/8

This Article is brought to you for free and open access by the Department of Geology and Geophysics at LSU Digital Commons. It has been accepted for inclusion in Faculty Publications by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. International Geology Review

ISSN: 0020-6814 (Print) 1938-2839 (Online) Journal homepage: https://www.tandfonline.com/loi/tigr20

Sedimentary budget of the Northwest Sub-basin, South China Sea: controlling factors and geological implications

Yanmei Wu, Weiwei Ding, Peter D. Clift, Jiabiao Li, Shaoru Yin, Yinxia Fang & Hanghang Ding

To cite this article: Yanmei Wu, Weiwei Ding, Peter D. Clift, Jiabiao Li, Shaoru Yin, Yinxia Fang & Hanghang Ding (2019): Sedimentary budget of the Northwest Sub-basin, South China Sea: controlling factors and geological implications, International Geology Review, DOI: 10.1080/00206814.2019.1597392 To link to this article: https://doi.org/10.1080/00206814.2019.1597392

Published online: 31 Mar 2019.

Submit your article to this journal

Article views: 515

View related articles

View Crossmark data

Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=tigr20 INTERNATIONAL GEOLOGY REVIEW https://doi.org/10.1080/00206814.2019.1597392

ARTICLE Sedimentary budget of the Northwest Sub-basin, South China Sea: controlling factors and geological implications Yanmei Wu a,b, Weiwei Dingb, Peter D. Cliftc, Jiabiao Lib, Shaoru Yinb, Yinxia Fangb and Hanghang Dinga,b aSchool of Earth Sciences, Zhejiang University, Hangzhou, China; bKey Laboratory of Submarine Geoscience, Second Institute of Oceanography, Ministry of Natural Resources of the People’s Republic of China, Hangzhou, China; cDepartment of Geology and Geophysics, Louisiana State University, Baton Rouge, USA

ABSTRACT ARTICLE HISTORY We calculated the sedimentary budget of the Northwest Sub-basin (NWSB), South China Sea for Received 10 December 2018 different geological times based on interpretations of four multichannel seismic profiles across Accepted 17 March 2019 the basin with constraints from International Ocean Discovery Program (IODP) Expeditions 367 KEYWORDS and 368 drilling results. Sedimentation was generally dominated by regional tectonic events and Sedimentary budget; climate change, but complicated by local tectonic events and geographic position, which sediment provenance; Asian resulted in a specific sedimentary budget in the NWSB compared with other marginal basins monsoon; sea-level change; and the Southwest Sub-basin. The sedimentation rate was relatively low following the opening of International Ocean the NWSB but increased gradually during the Middle Miocene, corresponding to the uplift of the Discovery Program; Tibetan Plateau and the Asian monsoon. It reached its peak in the Late Miocene, corresponding Expeditions 367 and 368; to uplift of the Dongsha Island region that caused intensive bypass of eroded sediments from the Northwest Sub-basin Baiyun Sag into the abyssal basin, and reduced again during the Pliocene because of sediment storage on the wide northern continental shelf area compared to the abyssal basin during a period of high-stand sea level. Increase in sedimentation during the Pleistocene suggests that continental erosion and sediment transport to the abyssal basin were enhanced by an intensified Asian summer monsoon and glacial-interglacial climate fluctuations. Since the opening of the NWSB, the primary sediment provenance has been from southern China, with minor contributions from the Red River, Hainan Island, as well as local uplifts on the continental shelf.

1. Introduction Systematic reconstruction of the sedimentary budget of the SCS must consider the sediments deposited both Variations in sedimentary budgets through time in on the continental margin and the abyssal basin. Given onshore and offshore basins can be used to constrain the abundant multichannel seismic surveys and commer- erosion rates and be related to tectonic and climate cial drilling works for hydrocarbon exploration in the changes to test for possible links (Clift and Sun 2006; continental margins, sedimentary processes and tectonic Yan et al. 2011). As one of the largest marginal sea basins activities in those settings have been extensively studied, in the Western Pacific, the South China Sea (SCS) plays including the Yinggehai-Song Hong Basin (Clift and Sun asignificant role in mass transport and accumulation 2006;Yanet al. 2011;Leiet al. 2015), Qiongdongnan Basin since the initial continental rifting in the Late Cretaceous (Gong et al. 2011;Huet al. 2013), and Pearl River Mouth (e.g. Clift 2006, 2015; Huang and Wang 2006; Liu and Basin (Ding et al. 2013a;Liet al. 2016;Sunet al. 2017)in Stattegger 2014). The SCS is a significant sink and receives the northern continental margin, the Indo-China approximately 700 million tons of sediments annually, of Peninsula continental margin in the west (Lee et al. which approximately 80% are supplied by the Mekong, 2001; Murray and Dorobek 2004;Clift2006;Liuet al. Red, and Pearl Rivers, while the remainder is derived from 2007;Liet al. 2013), and the southern continental margin smaller mountainous rivers (Huang 2004;Liuet al. 2008). (Steinke et al. 2003; Charles and Hutchison 2004). All these Sedimentary flux changes in the SCS could reflect its previous works significantly contributed to our under- response to interplays between climate, tectonics, and standing of Cenozoic sedimentary processes and control- the evolution of large-scale drainage patterns during dif- ling factors in the SCS. However, the sedimentary budget ferent geological times (Clark et al. 2004;Clift2006;Clift analysis of the abyssal basin remains limited because of and Sun 2006;Yanet al. 2011). the lack of drilling wells.

CONTACT Weiwei Ding [email protected] Key of Submarine Geoscience, Second Institute of Oceanography, Ministry of Natural Resources of the People’s Republic of China, Baochubei Road 36, Hangzhou 310012, China © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way. 2 Y. WU ET AL.

In 2014, International Ocean Discovery Program 3500 m and 4000 m (Gao 2012). The NWSB is bounded (IODP) Expedition 349 drilled five sites in the abyssal by several tectonic units: the Baiyun Sag of the Pearl basin; at three sites, basalt near the fossil spreading River Mouth Basin to the north, the Xisha Islands to the ridge was penetrated and the overlying sedimentary west, the Qiongdongnan Basin to the northwest, and cover was recovered (Li et al. 2015a). In the subsequent the Zhongsha Islands to the south. The NWSB is sepa- IODP Expeditions 367 and 368 in 2017, seven sites were rated from the ESB by the Zhongnan Fault in the drilled in the continent-ocean transition zone, with two (Figure 1) (Ding et al. 2011; Gao 2012). of which penetrated the basaltic basement of the ocea- Recent results acquired from IODP Expedition 349 nic basin (Jian et al. 2018;Sunet al. 2018). With these confirmed that seafloor spreading in the East Sub- drilling results and multichannel seismic (MCS) data, well basin initiated at ~32 Ma and terminated at ~15 Ma, dated abyssal stratigraphy and the lithologies of differ- and the Southwest Sub-basin started seafloor ent sedimentary units are now possible. The sedimentary spreading at ~23.6 Ma and ceased at ~15 Ma budget of the Southwest Sub-basin has been con- (Expedition 349 Scientists 2014; Koppers 2014;Li strained using this approach (Ding et al. 2016;Wuet al. et al. 2014, 2015b). However, the study on the 2018). Results show that the uplift of Tibetan Plateau, the spreading stage of the NWSB was limited. Early mag- accelerated southeastward extrusion of the Indochina netic anomaly interpretations suggested that the Peninsula, and the East Asia monsoon dominated control spreading of the NWSB began at about 30–32 Ma of the sedimentary budget. The sedimentary provenance (Briais et al. 1993). Seismic stratigraphic correlation was mainly the Indochina, with minor contributions from also confirmed that the NWSB started spreading the Dangerous Grounds/Nansha areas and Palawan. nearly at the same time as the ESB (Sun et al. 2006; Huang and Wang (2006) calculated the sediment Li et al. 2015a). The NWSB stopped spreading after mass for the entire SCS for the first time, but their result a southward ridge jump at 25–23 Ma, and experi- remains contentious because their seismic stratigraphic enced thermal subsidence thereafter (Barckhausen and sedimentary framework was not precisely con- et al. 2014; Cameselle et al. 2015), indicating the strained. In this study, we integrated the drilling results cessation of the spreading. and downhole geophysical logging from IODP Since the opening of the SCS, terrigenous materials Expeditions 367 and 368, with MCS data to conduct were transported from the continental shelf to the abys- a detailed seismic stratigraphy study of the Northwest sal basin during the lowstand stage through canyon and Sub-basin (NWSB), and then calculated the sedimentary channel systems, including the Pearl River Canyon sys- budget through time, in doing so we reconstructed the tem in the north and the Central Canyon in the west sedimentary history of the NWSB. To better understand (Ding et al. 2013a, 2013b;Shanget al. 2015;Liet al. the significance of sediment volumes deposited in the 2017). The Pearl River Canyon was initially formed as NWSB, we compared our results with the sedimentary a result of the rapid thermal subsidence in the Baiyun budget of continental margin basins, such as the Pearl Sag and several eustatic events of the Pearl River Mouth River Mouth Basin, the Yinggehai-Song Hong Basin, and Basin since the Early Miocene, and it was the main the Qiongdongnan Basin (Clift 2006; Clift and Sun sediment transport conduit in this region (Ding et al. 2006), as well as the Southwest Sub-basin (Wu et al. 2013b). Meanwhile, the Central Canyon developed 2018). The objective of the sedimentary budget studies along the Xisha Trough, and its formation time was is to determine the flux and transport paths of terres- delayed until the Late Miocene (Su et al. 2013, 2014). trial sediments, and to identify the major controlling factors over the sedimentary budget in order to 3. Data and method increase understanding of the interaction between solid earth tectonic activity, climate change, and sedi- In this study, we reinterpret four multichannel seismic mentary evolution of the NWSB, SCS. profiles across the NWSB in two different orientations with new dating constraints from IODP Expeditions 367 and 368 (Figure 1). Seismic profiles SO49-17, SO49-18, 2. Geological setting and SO49-25 were collected during the ‘Joint Sino- The SCS is comprised of three major sub-basins: the German South China Sea Cruise’ in 1987, and seismic NWSB, the East Sub-basin (ESB), and the Southwest profile 97303 was obtained by the ‘Project 973 Cruise’ Sub-basin (SWSB) (Li et al. 2015a; Gao et al. 2018). in 2009. More details about the acquire paraments of Among the three sub-basins, the NWSB is the smallest the seismic profiles are presented in Table 1. one with a total width of nearly 200 km and a total Five sites in the continental slope and abyssal basin length of about 140 km. Its water depth is between were drilled during IODP Expeditions 367 and 368 (Sites INTERNATIONAL GEOLOGY REVIEW 3

Figure 1. (a) Major tectonic units and sedimentary basins in the South China Sea. Red dashed square shows the study area. And purple dashed square shows the location of the base map in the Figure 7. Red broken line shows the boundary between the Northwest Sub-basin, the Southwest Sub-basin and the East Sub-basin. Red solid line shows the Red River Fault Zone. (b) Bathymetric map showing geophysical context of the study area around the Northwest Sub-basin. The black lines indicate the locations of seismic proﬁles described in this paper. The red dots indicate the location of ODP Site 1148, IODP Sites U1499, U1500, U1501, U1502, and U1504. 4 Y. WU ET AL.

Table 1. Acquisition paraments for seismic lines used in this study. Expeditions 367 and 368 (Jian et al. 2018;Sunet al. profile SO49-17, SO49-18, SO49-25 97303 2018). As the resulting equation expresses, an exponential R/V SONNE TANBAO fit for shallow depths (z < 150 m below seafloor, mbsf) Acquisition date 1987 2009 coupled with a linear fit for greater depths (z > 150 mbsf) Streamer channel 48 480 Record length (s) 12 12 best describes the porosity trend. The porosity-depth Sampling rate (ms) 4 2 equation is expressed as below: Shot interval (m) 50 50 Airgun volume (L) 25.6 83.3 : e0:00759z þ : ðÞz mbsf ϕðÞ¼z 0 356 0 426 150 2:053 104z þ 0:586 ðz > 150 mbsfÞ

U1499, U1500, U1501, U1502 and U1504) (Figure 1), cor- Here, ϕðÞz is the porosity function and in decimal, and ing through Cenozoic sediments overlying basement. depth z is in mbsf. Drilling sites from these expeditions were used to inter- With this porosity-depth relationship, we decom- pret sediment units and sequence boundaries, especially pacted deeply buried stratigraphic units to sedimentary for seismic profile 97303, which lies very close to the units, assuming a constant volume of rock grains before drilling area so that the lithology and age of both sedi- and after the decompaction (Steckler and Watts 1978), ments and the basement are now well constrained by using the following equation: along-line projection from Site U1499. Age control of the x y ò ½1 ϕðÞz dz ¼ ò 2 ½1 ϕðÞz dz sequence boundaries is mostly provided by biostrati- 0 y1 graphic analysis (Sun et al. 2018). In this study, we distin- Here, ϕðÞz is the porosity-depth function, x is the guished six distinct seismic units in Cenozoic sediments decompacted thickness, and y1 and y2 are the top and corresponding to distinct tectono-sedimentary environ- bottom depths of the sedimentary unit, respectively. y1 ments, i.e. the Oligocene, the Lower Miocene, the Middle and y2 will change with the depth of different sedimen- Miocene, the Upper Miocene, the Pliocene, and the tary units. The left term is the volume of rock grains Pleistocene, from bottom to top respectively (Figure 2). after decompaction, and the right term defines the The calculation of the sedimentary budget involves volume before decompaction. time-depth conversions of the interpreted seismic sec- After obtaining the uncompacted thickness of each tions (Figures 3–6). A full suite of geophysical logging sedimentary unit (Figures 3(c), 4(c), 5(c)and6(c)), we calcu- was carried out at Site U1499, which enabled an accu- lated the sediment volume of the NWSB at different times rate time-depth conversion. With core-log-seismic inte- using Surfer software. By importing the unloaded and gration, Sun et al.(2018) built a time-depth conversion decompacted depth of each sedimentary boundary into function, expressed as follows: the Surfer software by Golden Software, LLC, the interface Z ¼ 0:000188295t2 þ 0:695896t; grid data can be generated and followed by a planar graph. Longitude and latitude data from each seismic profile are where t stands for the two-way travel time starting from also used to directly constrain the surface area of the NWSB. the seafloor (in milliseconds), and z is the depth in The sediment volume between two sequence boundaries meters below the seafloor (mbsf). can be finally determined by computing the grid volume in After time-depth conversion, we decompacted each between these two boundaries. After the sediment volume sedimentary unit in order to obtain their original thickness and average sedimentary rate for five sedimentary units are using the program Flex-Decomp™ by Kusznir et al.(1995). confirmed,thesedimentarybudgetoftheNWSBindiffer- During the decompaction process, the loss of porosity of ent geological time periods is determined. each sedimentary unit is estimated. In this study, an accu- Errors in the calculation results can be caused by various rate porosity-depth relationship was built by employing processes: (a) The time–depth conversion error is assumed porosity data obtained from Site U1502 during IODP to be 3%. Three different sites in the central SCS basin

Table 2. Calculation results of the sedimentary budget of the NWSB. Time Period Duration Sediment Volume Surface Area Average Sediment Thickness Sedimentary Budget Time (Ma) (m.y.) (km3) (km2) (m) (1000 km3/my) Pleistocene 1.8–0 1.8 4050 22,152 182 2.25 ± 0.22 Pliocene 5.3–1.8 3.5 4482 22,152 202 1.28 ± 0.13 L. Mio. 10.6–5.3 5.3 14,198 22,155 640 2.68 ± 0.26 M. Mio. 16–10.6 5.4 8577 22,154 387 1.59 ± 0.16 E. Mio.-Oli 23–16 11.5 7506 22,075 340 0.65 ± 0.07 32–16 (As the basement boundary is diachronous, the duration of the Lower Miocene-Oligocene sediment is taken the average as 11.5 Ma.) INTERNATIONAL GEOLOGY REVIEW 5

Figure 2. Calibration of seismic horizons from Site U1499. The interpreted boundaries are calibrated from recovered lithostrati- graphy. Site U1499 is located on a basement ridge within the continent-ocean transition zone of the SCS. At Site U1499, the basaltic basement was not penetrated but most Cenozoic sediments could be recovered. See location in Figure 1.

(U1431, U1432 and U1433 from IODP Expedition 349) also the sedimentary filling history. We consider the give nearly identical time-depth relationships (Li et al. Oligocene and Lower Miocene as one unit because 2015a), indicating the high accuracy of the time-depth they represent the syn-rift sediment of the SCS. conversion. (b) Errors in estimating the sediment age, lithol- Isopach maps of five sediment units, i.e. the Oligocene ogy, and compaction history rarely exceed 2% (Clift 2006). and Lower Miocene, the Middle Miocene, the Upper Especially during the decompaction process, the porosity- Miocene, the Pliocene, and the Pleistocene, are shown depth data cluster closely around the function, suggesting in Figure 7. the homogenous sedimentation in the abyssal basin. (c) During the Oligocene and Early Miocene, the sedi- Errors in calculating the sedimentary volume for different ment thickness was between 200–400 m in the slope sedimentary units are estimated to be 5% at most, because area, but decreased to less than 100 m in most parts of oflimited2Dseismicprofiles. In addition, the errors in the abyssal basin (Figure 7(a)). A sediment belt with calculating the sedimentary volume are generally set as higher thickness ran across the abyssal basin with an 5% in previous study (Clift 2006;Leiet al. 2015)Compared N-S trend. The belt started from the mouth of Pearl to previous studies, these errors are reduced because the River Canyon and thickened towards the south. confirmation of the sedimentary units is more accurate. Extremely thick sediments, reaching 1000 m, existed in Thus, we set the total error range as ±10%. the southeastern part of the NWSB. The thick sediment belt generally developed along the Zhongnan Fault. During the Middle Miocene, sedimentary rate 4. Results increased, and the sedimentary thickness of this stage was generally over 100 m, reaching up to 500 m in the 4.1. Sediment isopach mapping in five central part (Figure 7(b)). A thick N-S trending sedimen- time-periods since Oligocene tary belt can still be observed along the Zhongnan The multichannel seismic profiles constrained by the Fault, which connects with the Pearl River Canyon in biostratigraphy of Site U1499 allowed us to explore the north. Only restricted areas, such as the basement 6 Y. WU ET AL.

Figure 3. MCS section SO49-17 oriented in a SE-NW direction. (a) Original seismic section; (b) geological interpretation with line drawing; (c) time-depth conversion of the geological interpretations. Oligocene and Lower Miocene sediments that experienced the syn-rift stage of the South China Sea. Decompacted thicknesses of each sedimentary unit provide the foundation for sedimentary budget calculation of the NWSB. Vertical exaggeration is 3:1. INTERNATIONAL GEOLOGY REVIEW 7

Figure 4. MCS section SO49-18 oriented in a SE-NW direction. (a) Original seismic section; (b) geological interpretation with line drawing; (c) time-depth conversion of the geological interpretations. A buried seamount developed in the central part of the seismic proﬁle. Vertical exaggeration is 3:1. 8 Y. WU ET AL.

Figure 5. MCS section SO49-25 oriented in a NE-SW direction. (a) Original seismic section; (b) geological interpretation with line drawing; (c) time-depth conversion of the geological interpretations. Vertical exaggeration is 3:1. INTERNATIONAL GEOLOGY REVIEW 9

Figure 6. MCS section 97303 oriented in a NW-SE direction. Top: Original seismic section; Bottom: geological interpretation with line drawing. A buried seamount can be observed in the central part of the seismic profile. Vertical exaggeration is 3:1. highs in the abyssal basin, exhibited limited sedimenta- The sedimentary budget in the abyssal basin exhibits tion with thicknesses lower than 100 m. a wavy shape. As shown in Table 12 the sedimentary bud- A sharp increase in sedimentation occurred during get was 0.65 ± 0.07 × 103 km3/my from the Late Oligocene the Late Miocene, and the thickness of the Upper to the Early Miocene (32–16 Ma), and gradually increased to Miocene in the abyssal basin was generally over 500 m, 1.59 ± 0.16 × 103 km3/my during the Middle Miocene reaching ~800 m in the central part (Figure 7(c)), with (16–10.6 Ma). It reached its peak during the Late the exceptions above the buried seamounts (Figure 4). Miocene (10.6–5.3 Ma), which was approximately The isopach map also shows a similar sedimentary belt 2.68 ± 0.27 × 103 km3/my. Since the Pliocene (5.3–1.8 Ma), with thickness higher than 600 m, which again starts there was an obvious decline with the sedimentary budget from the mouth of the Pearl River Canyon and develops value reduced to 1.28 ± 0.13 × 103 km3/my, almost half of further south along the Zhongnan Fault. the previous rate. Nevertheless, it increased again Since the Pliocene, the sediments were generally to 2.25 ± 0.23 × 103 km3/my in the Pleistocene (1.8 sheet-like and have no obvious depocenter. Both of the Ma–present). sediment thickness of the Pliocene and the Pleistocene were ~200 m, reaching 300 m locally (Figure 7(d,e)). 5. Discussion 5.1. Controls on sedimentary budget 4.2. Sedimentary budget calculation results Sedimentary basins in the continental margin of the SCS, Based on the methods described above, we calculated such as the Pearl River Basin, had sufficient accommoda- the sedimentary budget of the NWSB for different geo- tion space and acquired most terrestrial sediments from logical times. Previous works on the Qiongdongnan South China since Cenozoic. Furthermore, the Baiyun Sag Basin (Clift and Sun 2006), the Pearl River Mouth Basin experienced rapid thermal subsidence from 29 Ma to (Clift 2006), and the Baiyun Sag (Xie et al. 2013) are also 23.3 Ma (Zhou et al. 2009;Xieet al. 2013), which not presented in Figure 7 for comparison. only trapped abundant terrigenous sediments, but also 10 Y. WU ET AL.

Figure 7. Isopach map showing the decompacted thicknesses of sediments for different geological times. (a) Late Oligocene to Early Miocene, (b) Middle Miocene, (c) Late Miocene, (d) Pliocene, (e) Pleistocene. The red dashed line indicates the Zhongnan Fault based on Li et al.(2014). The blue dashed line indicates the continent-ocean boundary (COB) (Li et al. 2014). Black lines indicate four multichannel seismic profiles. The red dot indicates the location of Site U1499. The question marks indicate the lack of constraints from seismic data. INTERNATIONAL GEOLOGY REVIEW 11 caused the northward migration of the continental shelf ~5.5 Ma, interpreted to be caused by magma intru- break. This could explain the extremely low sedimentary sion within the basement (Luedmann and Wong 1999; rate in most of the NWSB despite the increased sedimen- Sun et al. 2014). The region near the Dongsha Islands tary flux in the Yinggehai-Song Hong Basin, Pearl River experienced intensive erosion, as evidenced by the Mouth Basin, and Baiyun Sag. An exception is the abyssal missing Neogene sediments around the crest of the basin near the Zhongnan Fault, which preserved relatively Dongsha Uplift (Luan et al. 2012). The eroded sedi- thick sediments. This may be attributed to the dramati- ments would initially have been transported into the cally decreased relative sea level after 21 Ma (Pang et al. Baiyun Sag (Ma et al. 2015;Heet al. 2017). Studies of 2005, 2009). Terrigenous sediments carried by the Paleo- the sedimentary process have demonstrated that the Pearl River incised the continental slope area, resulting in Baiyun Sag was infilled by sediment delivered from the development of the Pearl River Canyon (Ding et al. the Pearl River with extremely low sedimentary rates 2013a, 2013b;Caoet al. 2018). As a result, some terrige- since 10.5 Ma (Wang et al. 2018)(Figure 8(d)). Thus nous sediments could be transported into the abyssal little sediments were captured by the Baiyun Sag at basin and accumulated along the negative traps due to that time, allowing overspill into the NWSB though the activities of the Zhongnan Fault during the Early the Pearl River Canyon. Consequently, the sedimen- Miocene. tary rate of the Pearl River Mouth Basin decreased During the Middle Miocene (16–10.6 Ma), the sediment while the sedimentary rate of the NWSB increased at flux to the NWSB increased dramatically, with an average thesametime(Figure 9(c,f)). increment of about 0.94 × 103 km3/my (Figure 8(f)). During the Pliocene (5.3–1.8 Ma), the East Asian Although the sediment flux to the Qiongdongnan Basin summer monsoon strengthened again, and the climate did not significantly change (Figure 8(b)), the mass of sedi- switched to warm and humid (Wang et al. 2003; Clift ments in the Yinggehai-Song Hong Basin and Pearl River et al. 2014). As shown in Figure 9(b), δ18O increased Mouth Basin showed significant increase (Figure 9(a,c)). rapidly during the Pliocene, indicating increased tem- Both basins were connected to onland rivers, i.e. the Red perature. As a result, the sedimentary budget increased River and the Pearl River. Meanwhile, the increased sedi- in marginal basins including the Pearl River Basin, ment flux from the Red River could be attributed to the Yinggehai-Song Hong Basin, and Qiongdongnan Basin, uplifting event of the Tibetan Plateau and the intensifica- and in the SWSB. However, the sedimentary budget of tion of the Asian summer monsoon (Clift 2006;Cliftand the NWSB again showed a contrasting trend, decreas- Sun 2006;Wanet al. 2010;Tadaet al. 2016), while that from ing to about 1.40 × 103 km3/my during this stage. the Pearl River was mainly controlled by a climate trigger Compared with the narrow Indochina continental shelf (Sun et al. 2008;Cliftet al. 2015)(Figure 9(c)). During this in the west of the SWSB, the northern continental shelf stage, the sedimentary rate of the Pearl River Mouth Basin exceeds 350 km in the N-S orientation, and most of the (Figure 8(c)),aswellastheBaiyunSag(Figure 8(d)), was terrestrial sediments were deposited in the continental much higher than that of the Qiongdongnan Basin, indicat- shelf area during high-stand stage (Pang et al. 2009; Xie ing that the sediment influx into the NWSB was primarily et al. 2013)(Figure 9(a)). Therefore, the sedimentary rate from the north. Sediments were transported through the increased in the Pearl River Mouth Basin but declined Pearl River Canyon, which developed and matured during both in the Baiyun Sag and NWSB (Figure 9(c,d,f)). In theMiddleMiocenewiththeapparentdeclineofrelative contrast, the SWSB showed a swift response to the sea level of the SCS (Figure 9(a)), although most sediments strengthened summer monsoon and chemical weath- were deposited in the Baiyun Sag. ering, resulting in an increased sedimentation rate. The sedimentary budget of the NWSB reached its The sedimentary budget for the entire abyssal basin peak during the Late Miocene (10.6–5.3 Ma). It is increased again during the Pleistocene (1.8–0 Ma). The noteworthy that in most other places, either in the intensification of the Asian monsoon during interglacial continental margins or in the SWSB, the sediment rate periods and the variation of glacial-interglacial climate dramatically decreased, which may be associated with (Figure 9(b)) is consistent with the observation that the the increased aridity and stronger winter monsoon Pleistocene was indeed a period of rapid sedimentation across Asia at that time (Clift 2006). This arid climate for many other basins, not only in the SCS, but also in decreased erosion rates in terrestrial drainage basins other regions, such as the European Alps region and resulted in low sedimentation rates (Wan et al. (Kuhlemann et al. 2002), or the Angola continental 2006, 2007). The opposite trend in the NWSB may be margin of West Africa (Lavier et al. 2001). Furthermore, attributed to an uplift event near the Dongsha Islands, global sea level declined during this period (Haq et al. known as the Dongsha Event, which commenced in 1987). The rejuvenation of the Pearl River Canyon and the Late Miocene and had a peak of activity at the Central Canyon System led to the increased 12 Y. WU ET AL.

Figure 8. Sedimentary budgets for the major marginal and abyssal basins in the South China Sea. (a) Yinggehai-Song Hong Basin (Clift and Sun 2006), (b) Qiongdongnan Basin (Clift and Sun 2006), (c) Pearl River Mouth Basin (Clift 2006), (d) Baiyun Sag (Xie et al. 2013), (e) Southwest Sub-basin (Wu et al. 2018), and (f) Northwest Sub-basin. INTERNATIONAL GEOLOGY REVIEW 13

Figure 9. (a) Relative eustatic fluctuations of the Pearl River Mouth Basin from Pang et al.(2005). (b) δ18O curve (red line) with global deep-sea oxygen isotope records (purple squares) indicating climatic shifts (Zachos et al. 2001). MMCO: Middle Miocene climatic optimum. (c) Chemical weathering index CRAT (errors □ 0.1) as a function of time (Clift et al. 2008). (d) Sedimentary budget changes for the entire study area. Vertical dashed lines across all frames indicate boundaries between periods of dominantly weak or strong summer monsoon. 14 Y. WU ET AL. sediment shedding from the Pearl River, Red River, and During the Pliocene, the sedimentary flux to the Hainan Island (Su et al. 2013, 2014; Ding et al. 2013a) NWSB was decreased due to the sea-level highstand. (Figure 9(d)). Most terrestrial sediments were deposited on the continental shelf to the north. Both the Pearl and Red Rivers contributed little to sedimentation in the NWSB. 5.2. Sediment provenance The isopach map for this stage shows that the sedimen- Since its opening, the SCS has received hundreds tary thickness is generally higher in the west than that of million metric tons (Mt) of fluvial sediments annually in the east, indicating active mass transportation from from numerous surrounding rivers, including the Pearl the west at that time. Using constraints from low tem- River, Red River, and Mekong River (Liu and Stattegger perature thermochronology, Shi et al.(2011) described 2014). Considering the location of the NWSB, the Pearl the Cenozoic denudation history of southern Hainan River in the north and the Red River in the northwest Island and indicated two periods of increased potential might have dominated the source-to-sink transport pro- sediment supply, which were the Late Eocene– cess of the NWSB and adjacent areas, although sediments Oligocene and since 5 Ma. Zhu et al.(2007) further from Hainan Island in the northwest, Macclesfield Bank/ argued that a fan delta developed in the south of the Zhongsha and Xisha Islands in the south, as well as local Hainan Island during 4.2–3.7 Ma. Sediments originating basement uplifts in the continental shelf area should be mainly from Hainan would have been transported into taken into account. the NWSB through the Central Canyon. As evidenced by both Nd bulk sediment and single Sediments were mainly transported from the mod- grain zircon provenance methods, the drainage of the ern Pearl River Canyon and Central Canyon during epi- Pearl River progressively expanded since the opening sodic sea-level lowstand events, as shown by the of the NWSB, evolving from relatively small rivers presence of two thick sedimentary zones near the confined to coastal South China in the Early mouths of these canyons (Figure 7(e)). After 1.8 Ma, Oligocene to a near-modern continental-scale drai- there were several potential sources of sediment, nage configuration in the Early Miocene (Liu et al. including the Red River and Hainan Island in the north- 2017;Caoet al. 2018). Bulk sediment geochemical west, small rivers in eastern Vietnam, and the Pearl analyses of Site U1435 and industrial wells indicated River to the north (Liu et al. 2016). Even suspended that the Pearl River and its tributaries have been the sediments delivered by small mountainous rivers in primary source of sediments to the northern conti- southwestern Taiwan could be deposited in the NWSB nental margin of the SCS (Liu et al. 2017). Sediments after transport by deep water currents (Liu et al. 2008). of the NWSB mainly originated from South China and Carbonate deposits, including carbonate platforms were transported by the Paleo-Pearl River through the and coral reefs on top of the basement highs, were Pearl River canyon during the sea-level lowstand. The well developed in the Xisha and Macclesfield Bank/ Central Canyon was not formed in this stage, and Zhongsha Islands since the Late Oligocene (Ma et al. sediments from northern and central Vietnam and 2011). While in the NWSB the cored sediments mainly Hainan Island were generally deposited in the comprised nannofossil-rich clay, clay with silt interbeds, Qiongdongnan Basin, contributing little to the NWSB claystone, silty sandstone, and sandstone (Sites U1499, (Yao et al. 2008;Zhaoet al. 2015). U1500, and U1502, Jian et al. 2018; Sun et al. 2018). Since the Late Miocene, Southeast Asia has been Biogenic carbonate was only recovered at Site U1500, affected by colder and drier climates due to the corresponding to Middle Miocene, but the carbonate strengthened winter monsoon, which weakened ero- contents were very low, all <0.5 wt% (Sun et al. 2018). sion, either from South China or from the Indochina We suggest that the contribution from the Xisha and Peninsula. We suggest that during this stage the Macclesfield Bank/Zhongsha Islands was extremely lim- increased sediment flux in the NWSB is mainly attribu- ited because most of the carbonate deposits were table to structural highs within the basin, such as the drowned since the middle Miocene. Dongsha Uplift. To the west, the Central Canyon within the Xisha 6. Conclusions Trough began to develop (Su et al. 2013, 2014, 2015). However, the low sedimentary rate in both the Based on geological interpretations of four seismic pro- Yinggehai-Song Hong Basin and the Qiongdongnan files across the NWSB and drilling results from IODP Basin at this time indicate slow terrestrial erosion Expeditions 367 and 368, we calculate the sedimentary (Figure 8(a,b)). We speculate that contributions to the budget of the NWSB during different geological times. NWSB from the west remained limited. The sedimentary budget of the Pearl River Mouth Basin, INTERNATIONAL GEOLOGY REVIEW 15

Yinggehai-Song Hong Basin, Qiongdongnan Basin, and was likely limited until the development of the Central SWSB were also integrated to constrain the sediment Canyon since the Late Miocene. The rejuvenation of the delivery history of the SCS. We reconstruct a relatively Central Canyon, strengthened summer monsoon, and low sedimentation rate during the Oligocene and Early episodic low-stand sea level events since the Miocene, which increased in the Middle Miocene and Pleistocene would have enhanced sediment transporta- peaked during the Late Miocene. The sedimentary rate tion into the NWSB. Local tectonic events, including the decreased sharply during the Pliocene but increased uplift event in the Dongsha Islands in the Late Miocene, again since the Pleistocene. and the uplift event in Hainan Island at ~5 Ma, also Cenozoic sediment delivery to the SCS is dominated contributed to the NWSB since the Pliocene. We suggest by major tectonic events linked to the geological history that the contribution of the Xisha and Macclesfield Bank/ of Southeast Asia, including uplift of the SE Tibetan Zhongsha Islands, as submerged banks, is extremely Plateau, continental rifting, the evolution of Asian mon- minor because almost no carbonate depositions have soon, development of the drainage systems of the Pearl been discovered in IODP drilling sites in this area. River and Red River, as well as eustatic sea level changes. However, sedimentation is complicated due to geographic position and local tectonic events. The sedimen- Acknowledgments tary budget of the NWSB shows two trends that being We thank the officers, technician, engineers, and crew members opposite to those of the SWSB and the continental of D/V JODIES Resolution for their contribution during drilling. margins of the SCS. In the late Miocene, the sedimentary We thank the Department of Geology and Geophysics, ff ’ rate peaked, while most of the continental margins Louisiana State University, for o ering a one-year visitor sposi- tion. This work was supported by the National Key Research and showed low rates because of the colder and drier cli- Development Program of China (2016YFC0600402), the mate and low intensive chemical weathering, attributa- National Programme on Global Change and Air-Sea ble to the strengthened winter Asian Monsoon and Interaction (GASI-GEOGE-01), the National Natural Science weak summer rains. Uplifting event near the Dongsha Foundation of China (91858214, 41676027), the NSFC- Islands occurred in the late Miocene, and Neogene sedi- Shandong Joint Fund of Marine Science Research Centers ’ ments with thicknesses of hundreds of meters were (U1606401). PC s involvement was supported by the Charles T. McCord Chair in Petroleum Geology. eroded and transported into the abyssal basin through the channel/canyon system, driving increasing sedimentary flux to the NWSB. The second opposite trend Disclosure statement occurred in the Pliocene, during which the sedimentary fl budget sharply decreased, while most basins in the No potential con ict of interest was reported by the authors. northern continental margin and the SWSB experienced an enhanced sedimentary budget due to the wet and Funding warm climate and enhanced chemical weathering and erosion with strengthened summer Asian monsoon. We This work was supported by the National Key R&D Program suggest that most of the terrestrial sediments would of China [2016YFC0600402]; National Natural Science Foundation of China [91858214, 41676027]; National have been deposited on the wide northern continental Programme on Global Change and Air-Sea Interaction shelf because of the high eustatic sea level during this [GASI-GEOGE-01]; NSFC-Shandong Joint Fund of Marine stage. Few sediments were transported into the abyssal Science Research Centers [U1606401]. basin. In contrast, such as offshore central Vietnam in the west of the SWSB, may be significant sources of sediment delivered to the abyssal basin even during ORCID high sea level. Yanmei Wu http://orcid.org/0000-0002-1020-1442 Structural analysis of the seismic profiles combined with bulk sediment geochemical analyses indicates that the primary sediment provenance was South China since References the opening of the NWSB. In particular, during sea level Barckhausen, U., Engels, M., Franke, D., Ladage, S., and lowstands, terrigenous sediments carried by the Pearl Pubellier, M., 2014, Evolution of the South China Sea: Revised River were probably transported directly to the slope ages for breakup and seafloor spreading: Marine and area and abyssal basin through well-developed chan- Petroleum Geology, doi:10.1016/j.marpetgeo.2014.02.022. Briais, A., Patriat, P., and Tapponnier, P., 1993, Updated inter- nel/canyon systems, such as the Pearl River Canyon, pretation of magnetic anomalies and seafloor spreading since the Early Miocene. Although the Red River or SE stages in the South China Sea: Implications for the tertiary Tibet cannot be excluded, their contribution to the NWSB tectonics of Southeast Asia: Journal of Geophysical 16 Y. WU ET AL.

Research: Solid Earth, v. 98, p. 6299–6328. doi:10.1029/ Ding, W.W., Li, M.B., Zhao, L.H., Ruan, A.G., and Wu, Z.L., 2011, 92JB02280. Cenozoic tectono-sedimentary characteristics and exten- Cameselle, A.L., Ranero, C.R., Franke, D., and Barckhausen, U., sion model of the Northwest Sub-basin, South China Sea: 2015, The continent-ocean transition on the northwestern Geoscience Frontiers, v. 2, p. 509–517. doi:10.1016/j. South China Sea: Basin Research, v. 29, p. 73–95. gsf.2011.05.010. doi;10.1111/bre.12137. Expedition 349 Scientists, 2014, South China Sea tectonics: Cao, L.C., Shao, L., Qiao, P.J., Zhao, Z.G., Douwe, J.J., and Opening of the South China Sea and its implications for Van, H., 2018, Early Miocene birth of modern Pearl River Southeast Asian tectonics, climate, and deep mantle pro- recorded low-relief, high-elevation surface formation of SE cesses since the late mesozoic: International Ocean Tibetan Plateau: Earth and Planetary Science Letters, v. 496, Discovery Program Preliminary Report, 349. p. 120–131. doi:10.1016/j.epsl.2018.05.039. Gao, H.F., 2012, Seismic facies’ characteristic of turbidites and Charles, S., and Hutchison, 2004, Marginal basin evolution: The sea level change in the northwest sub-basin of South China southern South China Sea: Marine and Petroleum Geology, Sea since late Miocene: Journal of Tropical Oceanography, v. 21, p. 1129–1148. doi:10.1016/j.marpetgeo.2004.07.002. v. 31, p. 113–119. doi;10.3969/j.issn.1009-5470.2012.03.015. Clark, M.K., Schoenbohm, L.M., Royden, L.H., Whipple, K.X., Gao, J., Peng, X.C., Wu, S.G., Ludmann, T., McIntosh, K., Ma, B.J., Burchfiel, B.C., Zhang, X., Tang, W., Wang, E., and Chen, L., and Xu, Z.Y., 2018,Different expressions of the crustal 2004, Surface uplift, tectonics, and erosion of eastern Tibet structure across the Dongsha rise along the northeastern from large-scale drainage patterns: Tectonics, v. 23, p. margin of the South China Sea: Journal of Asian Earth TC1006. doi;10.1029/2002TC001402. Sciences, doi:10.1016/j.jseaes.2018.01.034. Clift, P.D., 2006, Controls on the erosion of Cenozoic Asia and Gong, C.L., Wang, Y.M., Zhu, W.L., Li, W.G., Xu, Q., and Zhang, J. the flux of clastic sediment to the ocean: Earth and M., 2011, The central Submarine Canyon in the Planetary Science Letters, v. 241, p. 571–580. doi:10.1016/ Qiongdongnan Basin, northwest South China Sea: j.epsl.2005.11.028. Architecture, sequence stratigraphy, and depositional Clift, P.D., 2015, Assessing effective provenance methods for processes: Marine and Petroleum Geology, v. 28, p. fluvial sediment in the South China Sea, in Clift, P.D., 1690–1702. doi:10.1016/j.marpetgeo.2011.06.005. Harff, J., Wu, J.E., and Yan, Q., eds., River-dominated shelf Haq, B.U., Hardenbol, J., and Vail, P.R., 1987, Chronology of sediments of East Asian Sea: London, Special Publications fluctuating sea levels since the triassic: Science, v. 235, p. Geological Society, v. 429, p. 9-29. 1156–1167. doi;10.1126/science.235.4793.1156. Clift, P.D., Brune, S., and Quinteros, J., 2015, Cliamte changes He, M., Zhong, G.F., Liu, X.F., Liu, L.H., Shen, X.P., Wu, Z., and control offshore crustal structure at South China Sea con- Huang, K., 2017, Rapid post-rift tectonic subsidence events tinental margin: Earth and Planetary Science Letters, v. 420, in the Pearl River Mouth Basin, northern South China Sea p. 66–72. doi:10.1016/j.epsl.2015.03.032. margin: Journal of Asian Earth Sciences, v. 147, p. 271–283. Clift, P.D., Hodges, K.V., Heslop, D., Hannigan, R., Long, H.V., doi:10.1016/j.jseaes.2017.07.024. and Calves, G., 2008, Correlation of Himalayan exhumation Hu, B., Wang, L.S., Yan, W.B., Liu, S.W., Cai, D.S., Zhang, G.C., rates and Asian monsoon intensity: Nature Geoscience, v. 1, Zhong, K., Pei, J.X., and Sun, B., 2013, The tectonic evolution p. 875–880. doi;10.1038/ngeo351. of the Qiongdongnan Basin in the northern margin of the Clift, P.D., and Sun, Z., 2006, The sedimentary and tectonic South China Sea: Journal of Asian Earth Sciences, v. 77, p. evolution of the Yinggehai–Song Hong basin and the 163–182. doi:10.1016/j.jseaes.2013.08.022. southern Hainan margin, South China Sea: Implications for Huang, W., 2004, Sediment Distributional pattern and evolu- Tibetan uplift and monsoon intensification: Journal tion in the South China Sea since the Oligocene: [Doctoral Geophysical Research, v. 111, p. B06405. doi:10.1029/ Dissertation]: Shanghai, Tongji University, 113 p. 2005JB004048. Huang, W., and Wang, P.X., 2006, The statistics of sediment Clift, P.D., Wan, S.M., and Blusztajn, J., 2014, Reconstructing mass in the South China Sea: Method and results: Advances chemical weathering, physical erosion and monsoon inten- in Earth Science, v. 21, p. 465–473. sity since 25 Ma in the northern South China Sea: A review Jian, Z., Larsen, H.C., and Alvarez Zarikian, C.A., and The of competing proxies: Earth-Science Reviews, v. 130, p. Expedition 368 Scientists, 2018, Expedition 368 preliminary 86–102. doi:10.1016/j.earscirev.2014.01.002. report: South China Sea rifted margin: International Ocean Ding, W.W., Li, J.B., Clift, P.D., and IODP 349 Scientists, 2016, Discovery Program. doi:10.14379/iodp.pr.368.2018. Spreading dynamics and sedimentary process of the Koppers, A.A.P., and Expedition 349 Scientists, 2014,Onthe Southwest Sub-basin, South China Sea: Constraints from 40Ar/39Ar dating of low-potassium ocean crust basalt from multi-channel seismic data and IODP Expedition 349: IODP Expedition 349, South China Sea, Abstract T31E-03 pre- Journal of Asian Earth Sciences, v. 115, p. 97–113. sented at 2014 Fall Meeting, San Francisco, California, AGU. doi:10.1016/j.jseaes.2015.09.013. Kuhlemann, J., Frisch, W., Szekely, B., Dunkl, I., and Kazmer, M., Ding, W.W., Li, J.B., Fang, Y.X., and Tang, Y., 2013b, 2002, Post-collisional sediment budget history of the Alps: Morphotectonics and evolutionary controls on the Pearl Tectonic versus climatic control: International Journal of River canyon system, South China Sea: Marine Geophysical Earth Sciences, v. 91, p. 818–837. doi:10.1007/s00531-002- Research, v. 34, p. 221–238. doi:10.1007/s11001-013-9173-9. 0266-y. Ding, W.W., Li, J.B., Li, J., and Han, X.B., 2013a, Formation Kusznir, N.J., Roberts, A.M., and Morley, C.K., 1995, Forward process and controlling factors of the Pearl River Canyon and reverse modelling of rift basin formation: Geological in the South China Sea: Journal of Tropical Oceanography, Society London Special Publications, v. 80, p. 33–56. v. 32, p. 63–72. doi;10.3969/j.issn.1009-5470.2013.06.010. doi:10.1144/GSL.SP.1995.080.01.02. INTERNATIONAL GEOLOGY REVIEW 17

Lavier, L.L., Steckler, M.S., and Brigaud, F., 2001, Climatic and Paleogene: Marine Geology, v. 394, p. 52–68. doi:10.1016/ tectonic control on the Cenozoic evolution of the West j.margeo.2017.07.011. African margin: Marine Geology, v. 178, p. 63–80. Liu, Z.F., Colin, C., Huang, W., Le, K.P., Tong, S.Q., Chen, Z., and doi:10.1016/S0025-3227(01)00175-X. Trentesaux, A., 2007, Climatic and tectonic controls on Lee, G.H., Lee, K., and Watkins, J.S., 2001, Geologic evolution of weathering in south China and Indochina Peninsula: Clay the Cuu Long and Nam Con Son basins, offshore Southern mineralogical and geochemical investigations from the Vietnam, South China Sea: AAPG Bulletin, v. 85, p. Pearl, Red and Mekong drainage basins: Geochemistry, 1055–1082. Geophysics, Geosystems, v. 8, p. Q05005. doi;10.1029/ Lei, C., Ren, J.Y., Sternai, P., Fox, M., Willett, S., Xie, X.N., Clift, P. 2006GC001490. D., Liao, J.H., and Wang, Z.F., 2015, Structure and sediment Liu, Z.F., and Stattegger, K., 2014, South China Sea fluvial sedi- budget of Yinggehai- Song Hong basin, South China Sea: ments: An introduction: Journal of Asian Earth Sciences, v. 79, p. Implications for Cenozoic tectonics and river basin reorga- 507–508. doi:10.1016/j.jseaes.2013.11.003. nization in Southeast Asia: Tectonophysics, v. 655, p. Liu, Z.F., Tuo, S.T., Colin, C., Liu, J.T., Huang, C.Y., Selvaraj, K., 177–190. doi:10.1016/j.tecto.2015.05.024. Chen, C.T.A., Zhao, Y.L., Siringan, F.P., Boulay, S., and Li, C., Lv, C.F., Chen, G.J., Zhang, G.C., Ma, M., Shen, H.L., Chen, Z., 2008, Detrital fine-grained sediment contribution Zhao, Z., and Guo, S., 2017, Source and sink characteristics from Taiwan to the northern South China Sea and its rela- of the continental slope-parallel Central Canyon in the tion to regional ocean circulation: Marine Geology, v. 255, Qiongdongnan Basin on the northern margin of the p. 149–155. doi:10.1016/j.margeo.2008.08.003. South China Sea: Journal of Asian Earth Sciences, v. 134, Liu, Z.F., Zhao, Y.L., Colin, C., Stattegger, K., Wiensner, M.G., Huh, C. p. 1–12. doi:10.1016/j.jseaes.2016.10.014. A., Zhang, Y.W., Li, X.J., Sompongchaiyakul, P., You, C.F., Li, C.F., Li, J.B., Ding, W.W., Franke, D., Yao, Y.J., Shi, H.S., Huang,C.Y.,Liu,J.T.,Siringan,F.P., Le, K.P., Sathiamurthy, E., Pang, X., Cao, Y., Lin, J., Kulhanek, D.K., Williams, T., Hantoro, W.S., Liu, J.G., Tuo, S.T., Zhao, S.H., Zhou, S.W., He, Z. Bao, R., Briais, A., Brown, E.A., Chen, Y.F., Clift, P.D., D.,Wang,Y.C.,Bunsomboonsakul,S.,andLi,Y.L.,2016,Source- Colwell, F.S., Dadd, K.A., Almeida, I.H., Huang, X.L., to-sink transport processes of fluvial sediments in the South Hyun, S.M., Jiang, T., Koppers, A.A.P., Li, Q.Y., Liu, C.L., China Sea: Earth-Science Reviews, v. 153, p. 238–273. Liu, Q.S., Liu, Z.F., Renata, H., Nagai, R.H., Alampay, A.P., doi:10.1016/j.earscirev.2015.08.005. Su, X., Sun, Z., Tejada, M.L.G., Trinh, H.S., Yeh, Y.C., Luan, X.W., Zhang, L., and Peng, X.C., 2012, Dongsha erosive Zhang, C.L., Zhang, F., Zhang, G.L., and Zhao, X.X., 2015a, channel on northern South China Sea shelf and its induced Seismic stratigraphy of the central South China Sea basin Kuroshio South China Branch: Science China Earth Sciences, and implications for neotectonics: Journal of Geophysical v. 55, p. 149–158. doi:10.1007/s11430-011-4322-y. Research: Solid Earth, v. 120, p. 1377–1399. doi;10.1002/ Ludmann, T., and Wong, H.K., 1999, Neotectonic regime on 2014JB011686. the passive continental margin of northern South China Li, C.F., Lin, J., and Kulhanek, D.K., and The Expedition 349 Sea: Tectonophysics, v. 311, p. 113–138. doi:10.1016/ Scientists, 2015b, Proceedings of the International Ocean S0040-1951(99)00155-9. Discovery Program, 349: South China Sea Tectonics: College Ma, B.J., Wu, S.G., Sun, Q.L., Mi, L.J., Wang, Z.Z., and Tian, J., Station, TX, (International Ocean Discovery Program). 2015, The late Cenozoic deep-water channel system in the doi:10.14379/iodp.proc.349.2015. Baiyun Sag, Pearl River Mouth Basin: Development and Li, C.-F., Xu, X., Lin, J., Sun, Z., Yao, Y.J., Zhao, X.X., Liu, Q.S., tectonic effects: Deep-Sea Research II, v. 122, p. 226–239. Kulhanek, D.K., Wang, J., Song, T.R., Zhao, J.F., Qiu, N., doi:10.1016/j.dsr2.2015.06.015. Guan, Y.X., Zhou, Z.Y., Williams, T., Bao, R., Briais, A., Ma, Y.B., Wu, S.G., Lv, F.L., Dong, D.D., Sun, Q.L., Lu, Y.T., and Brown, E.A., Chen, Y.F., Clift, P.D., Colwell, F.S., Dadd, K.A., Gu, M.F., 2011, Seismic characteristics and development of Ding, W.W., Almeida, I.H., Huang, X.L., Hyun, S.M., Jiang, T., the Xisha carbonate platforms, northern margin of the Koppers, A.A.P., Li, Q.Y., Liu, C.L., Liu, Z.F., Nagai, R.H., South China Sea: Journal of Asian Earth Sciences, v. 40, p. Alampay, A.P., Su, X., Tejada, M.L.G., Trinh, H.S., Yeh, Y.C., 770–783. doi:10.1016/j.jseaes.2010.11.003. Zhang, C.L., Zhang, F., and Zhang, G.L., 2014, Ages and Murray, M.R., and Dorobek, S.L., 2004, Sediment supply, tec- magnetic structures of the South China Sea constrained tonic subsidence, and basin-filling patterns across the by deep tow magnetic surveys and IODP Expedition 349: southwestern South China Sea during Pliocene to recent Geochemistry Geophysical Geosystems, v. 15, p. time, in Clift, P., Wang, P., Kuhnt, W., and Hayes, D., eds., 4958–4983. doi;10.1002/2014GC005567. Continent-ocean interactions within East Asian marginal Li,G.,Yan,W.,andZhong,L.F.,2016, Element geochem- seas: Washington, DC, Geophysical Monograph-American istry of offshore sediments in the northwestern South Geophysical Union. V. 149, 235–254 p. China Sea and the dispersal of Pearl River sediments: Pang, X., Chen, C.M., Shi, H.-S., Shu, Y., Shao, L., He, M., and ProgressinOceanography,v.141,p.17–29. doi:10.1016/ Shen, J., 2005, Response between relative sea-level change j.pocean.2015.11.005. and the Pearl River deep-water fan system in the South Li, L., Clift, P.D., and Nguyen, H.T., 2013, The sedimentary, China Sea: Earth Science Frontiers, v. 12, p. 167–177. magmatic and tectonic evolution of the southwestern Pang, X., Chen, C.M., Zhu, M., He, M., Shen, J., Lian, S.Y., and Wu, X. South China Sea revealed by seismic stratigraphic J., 2009, Baiyun movement: A significant tectonic event on analysis: Marine Geophysical Research, v. 34, p. 341–365. Oligocene/Miocene boundary in the Northern South China doi:10.1007/s11001-013-9171-y. Sea and its regional implications: Journal of Earth Science, v. Liu, C., Clift, P.D., Carter, A., Boning, P., Hu, Z.C., Sun, Z., and 20, p. 49–56. doi:10.1007/s12583-009-0005-4. Pagnke, K., 2017, Controls on modern erosion and the Shang, Z.L., Xie, X.N., Li, X.S., Zhang, D.J., He, Y.L., Yang, X., and development of the Pearl River drainage in the late Cui, M.Z., 2015,Difference in full-filled time and its 18 Y. WU ET AL.

controlling factors in the Central Canyon of the Wan,S.M.,Clift,P.D.,Li,A.C.,andJiang,H.Y.,2006, Development of Qiongdongnan Basin: Acta Oceanologica Sinica, v. 34, p. the East Asian summer monsoon: Evidence from the sediment 81–89. doi:10.1007/s13131-015-0717-5. in the South China Sea since 8.5 Ma: Palaeogeography, Shi, X.B., Kohn, B., Spencer, S., Guo, X.W., Li, Y.M., Yang, X.Q., Palaeoclimatology, Palaeoecology, v. 241, p. 139–159. Shi, H.C., and Gleadow, A., 2011, Cenozoic denudation his- doi:10.1016/j.palaeo.2006.06.013. tory of southern Hainan Island, South China Sea: Constraints Wan, S.M., Clift, P.D., Li, A.C., Li, T.G., and Yin, X.B., 2010, from low temperature thermochronology: Tectonophysics, v. Geochemical records in the South China Sea: Implications 504, p. 100–115. doi:10.1016/j.tecto.2011.03.007. for East Asian summer monsoon evolution over the last 20 Steckler, M.S., and Watts, A.B., 1978, Subsidence of the Ma: Geological Society, London, Special Publications, v. Atlantic-type continental margin off New York: Earth and 342, p. 245–263. doi:10.1144/SP342.14. Planetary Science Letters, v. 41, p. 1–13. doi:10.1016/0012- Wan,S.M.,Li,A.C.,Clift,P.D.,andStuut,J.-B.W.,2007,Development 821X(78)90036-5. of the East Asian monsoon: Mineralogical and sedimentologic Steinke, S., Kienast, M., and Hanebuth, T., 2003, On the signifi- records in the northern South China Sea since 20 Ma: cance of sea-level variations and shelf paleo-morphology in Palaeogeography, Palaeoclimatology, Palaeoecology, v. 254, governing sedimentation in the southern South China Sea p. 561–582. doi:10.1016/j.palaeo.2007.07.009. during the last deglaciation: Marine Geology, v. 201, p. Wang, J.B., Pang, X., Liu, B.J., Zheng, J.Y., and Wang, H., 2018, 179–206. doi:10.1016/S0025-3227(03)00216-0. The Baiyun and Liwan Sags: Two supradetachment basins Su, M., Hsiung, K.-H., Zhang, C.M., Xie, X.N., Yu, H.-S., and on the passive continental margin of the northern South Wang, Z.F., 2015, The linkage between longitudinal sediment China Sea: Marine and Petroleum Geology, v. 95, p. routing systems and basin types in the northern South China 206–218. doi:10.1016/j.marpetgeo.2018.05.001. Sea in perspective of source-to-sink: Journal of Asian Earth Wang, P.X., Zhao, Q.H., Jian, Z.M., Cheng, X.R., Huang, W., Siences, v. 111, p. 1–13. doi:10.1016/j.jseaes.2015.05.011. Tian, J., Wang, J.L., Li, Q.Y., Li, B.H., and Su, X., 2003, Su, M., Xie, X.N., Wang, Z.F., Jiang, T., Zhang, C., and He, Y.L., Thirty million year deep-sea records in the South China 2013, Sedimentary evolution of the central canyon system Sea: Chinese Science Bulletin, v. 48, p. 2524–2535. in Qiongdongnan Basin, northern South China Sea: Acta doi:10.1007/BF03037016. Petrolei Sinica, v. 34, p. 467–478. Wu, Y.M., Ding, W.W., Sun, Z., Dong, C.Z., and Fang, Y.X., 2018, Su, M., Zhang, C., Xie, X.N., Wang, Z.F., Jiang, T., He, Y.L., and Sedimentary budget of the Southwest Sub-basin, South Zhang, C.M., 2014, Controlling factors on the submarine China Sea: Controlling factors and geological implications: canyon system: A case study of the Central Canyon system Geological Journal, doi:10.1002/gj.3145. in the Qiongdongnan Basin, northern South China Sea: Xie, H., Zhou, D., Pang, X., Li, Y.P., Wu, X.J., Qiu, N., Li, P.C., and Science China: Earth Science, v. 57, p. 2457–2468. Chen, G.H., 2013, Cenozoic sedimentary evolution of deep- doi;10.1007/s11430-014-4878-4. water sags in the Pearl River Mouth Basin, northern South Sun,Q.L.,Wu,S.G.,Cartwright,J.,Wang,S.,Lu,Y.,Chen,D.,and China Sea: Marine Geophysical Research, v. 34, p. 159–173. Dong, D., 2014, Neogene igneous intrusions in the northern doi;10.1007/s11001-013-9183-7. South China Sea: Evidence from high-resolution three dimen- Yan, Y., Carter, A., Palk, C., Brichau, S., and Hu, X., 2011, sional seismic data: Marine and Petroleum Geology, v. 54, p. Understanding sedimentation in the Song Hong–Yinggehai 83–95. doi:10.1016/j.marpetgeo.2014.02.014. Basin, South China Sea: Geochemistry Geophysics Sun,Q.L.,Xie,X.N.,Piper,J.W.D.,Wu,J.,andWu,S.G.,2017,Three Geosystems, v. 12, p. Q06014. doi:10.1029/2011GC003533. dimensional seismic anatomy of multi-stage mass transport Yao, G.S., Yuan, S.Q., Wu, S.G., and Zhong, C., 2008, Double deposits in the Pearl River Mouth Basin, northern South China provenance depositional model and exploration prospect Sea:Theiragesandkinematics:MarineGeology,v.393,p. in the deep-water area of Qiongdongnan Basin: Petroleum 93–108. doi:10.1016/j.margeo.2017.05.005. Exploration and Development, v. 35, p. 685–691. Sun, Z., Stock, J., and Klaus, A., and The Expedition 367 doi:10.1016/S1876-3804(09)60101-4. Scientists, 2018, Expedition 367 preliminary report: South Zachos, J., Pagani, M., Sloan, L., Thomas, E., and Billups, K., China Sea rifted margin: International Ocean Discovery 2001, Trends, rhythms, and aberrations in global climate 65 Program. doi:10.14379/iodp.pr.367.2018. ma to present: Science, v. 292, p. 686-693. Sun, Z., Zhong, Z.H., Zhou, D., Pang, X., Huang, C.J., Chen, C.M., Zhao, Z.X., Sun, Z., Wang, Z.F., Sun, Z.P., Liu, J.B., and Zhang, C. He, M., and Xu, H.H., 2008, Dynmics analysis of the Baiyun M., 2015, The high resolution sedimentary filling in Sag in the Pearl River Mouth Basin, North of the South Qiongdongnan Basin: Northern South China Sea: Marine China Sea: Acta Geologica Sinica, v. 82, p. 73–83. Geology, v. 361, p. 11–24. Sun, Z., Zhou, D., Zhong, Z.H., Xia, B., Qiu, X.L., Zeng, Z.X., and Zhou,D.,Sun,Z.,Liao,J.,Zhao,Z.X.,He,M.,Wu,X.J.,and Jiang, J.Q., 2006, Research on the dynamics of the South Pang, X., 2009, Filling history and post-breakup accel- China Sea opening: Evidence from analogue modeling: erationofsedimentationinBaiyunSag,deepwater Science in China Series D: Earth Science, v. 49, p. northern South China Sea: Journal of Earth Science, v. 1053–1069. doi;10.1007/s11430-006-1053-6. 20,p.160–171. Tada, R., Zheng, H.B., and Clift, P.D., 2016,Evolutionandvariability Zhu, W., Zhang, G., and Yang, S., 2007, Gas geology of the of the Asian monsoon and its potential linkage with uplift of the rifted basins on the northern continental margin. Himalaya and Tibetan Plateau: Progress in Earth and Planetary South China Sea: Beijing, Petroleum Industry Press. Science, v. 3. doi:10.1186/s40645-016-0080-y. 23–68 p.