Southern East China Sea Shelf Research Articles

The Cretaceous Sedimentary Environments and Tectonic Setting of the Southern East China Sea Shelf Basin

Although the amount of oil and gas reserves and the reservoir properties in the East China Sea Shelf Basin (ECSSB) indicate good prospects for oil and gas exploration in the Mesozoic strata, there has not yet been a significant breakthrough in oil and gas production. An important reason is that there are few detailed studies on the sedimentary paleogeography of the ECSSB which make it difficult to predict the distribution of sand bodies. In this paper, well-core observations, thin-section identifications, electron probe microanalysis, trace elements analysis and seismic interpretations were synthetically applied to study the sedimentary environments and the tectonic setting of the Upper Cretaceous in the southern ECSSB. In the Oujiang Sag, red mudstones and pyroclastic rocks were deposited, accompanied by wedged, chaotic pro-grading reflections in the seismic profile, indicating a volcano-alluvial fan sedimentary system. Abundant sedimentary structures including double-mud drapes, asymmetric herringbone cross-beddings and burrows, such as Planolites and Skolithos, were developed in the Minjiang Sag, typically indicating a high-energy tidal environment. The autogenetic glauconites in situ and the fossil Tintinnid also indicate a shallow marine environment. The resulting sedimentary characteristics are in accordance with the littoral facies revealed by the seismic reflections in the Minjiang Sag. Moreover, volcanic conduit facies, effusive facies, and pyroclastic facies were also recognized in the seismic profile in the Minjiang Sag. Therefore, it was presumed that subaqueous volcanic eruptions occurred in the Minjiang Sag. In the Keelung Sag, the littoral facies were dominant. The tectonic setting of the Upper Cretaceous in the southern ECSSB is the transitional arc accompanied by large-scale volcanic activities. In conclusion, the volcano-alluvial fan sedimentary system was developed in the Oujiang Sag and volcano-littoral sedimentary system was developed from the Minjiang Sag to the Keelung Sag. This study is intended to promote the understanding of the sedimentary paleogeography of the Upper Cretaceous in the southern ECSSB and to provide help in oil and gas exploration.

Distinct Variability between Semidiurnal and Diurnal Internal Tides at the East China Sea Shelf

Breaking internal tides and induced mixing are critical to shelf dynamics, including heat and mass exchanges. Spatiotemporal variability of internal tides and modulation factors for the southern East China Sea shelf were examined based on a combination of a three-month mooring velocity and satellite altimeter data. Semidiurnal and diurnal internal tides exhibited distinct temporal trends, with the semidiurnal internal tides enhanced by an order of magnitude during the latter half of the record, while the diurnal internal tides followed quasi spring-neap cycles with a generally stable intensity except for two specific periods of strengthening. These internal tides probably originated remotely over the shelf-slope area northeast of Taiwan. Time-varying stratification was the most important factor for the internal tidal magnitude. In addition, varying background currents influenced the diurnal critical latitude band, which explains the slightly enhanced diurnal internal tides during the two periods. Although both semidiurnal and diurnal internal tides were mode-1 dominated, the semidiurnal internal tides were surface intensified while the diurnal tides were bottom intensified. The proportion of higher mode internal tides increased during robust eddy activities. Stronger background vertical shear corresponded to high-frequency events and energy transfers from tidal frequencies to high frequencies associated with turbulent mixing.

Inter-annual variability in growth and maturation of the swordtip squid Uroteuthis edulis in Yilan Bay off northeastern Taiwan

The swordtip squid Uroteuthis edulis, distributed in the temperate and tropical neritic waters in the Indo-Pacific region, is a crucial component of marine ecosystems and is a target species of fisheries in the Northwest Pacific. Although studies have elucidated the growth and maturation of the squid in the southern East China Sea (ECS) shelf, few have assessed the population biology of the squid in waters in the vicinity of the southern ECS. We collected samples of swordtip squid from a trawler in Yilan Bay (YLB) between January 2011 and December 2012 to examine the growth and maturation of the squid based on statolith microstructures and the inter-annual variability in certain parameters as well as the potential underlying mechanisms. The average dorsal mantle length (ML) of the squid was significantly higher in 2011 than in 2012 in both sexes. The ML-body weight relationship differed significantly between 2011 and 2012 in both sexes. Squid hatching peaked in summer (June and August)in 2011 and spring (March and April) in 2012. The average ML-at-age data were described using the exponential function and power function for female and male squid, respectively. Female squid matured to 139 mm at 133 days in 2011 and to 133 mm at 137 days in 2012. Male squid matured to 160 mm at 151 days in 2011 and to 148 mm at 133 days in 2012. However, the ML- and age-at-maturity of the squid in YLB were lower than those of the squid in the southern ECS shelf. These results indicate that YLB is one of the feeding grounds for squid that have hatched in the southern ECS shelf and have been transported southward intermittently to YLB. Further study of the population structure and potential population connectivity of the squid in the entire ECS shelf is warranted to obtain data for the development of effective conservation and management measures for the squid and its fisheries in the Northwest Pacific.

Interpretation of Subsurface Salinity EOFs on Southern ECS Shelf Using SODA Reanalysis: Large‐Scale Patterns and Seasonal to Interannual Variations

AbstractIn the southern East China Sea (ECS), low‐salinity shelf water is distinguished from high‐salinity Kuroshio water. Neutral density solution of subsurface salinity in southern ECS with Empirical Orthogonal Function (EOF) analysis of Simple Ocean Data Assimilation (SODA) reanalysis data (1958‐2008) is presented. This study focuses on seasonal to interannual variations of large‐scale patterns. We choose isopycnal 24.5 as the representative of subsurface layers, which is the deepest of the Kuroshio subsurface that can outcrop to sea surface during winter and early spring. We conducted EOF both including and excluding the seasonal signal. The results show that annual cycles dominate the first two leading EOF modes, EOF‐1 representing inner‐shelf oscillation, and EOF‐2 outer‐shelf oscillation. However, EOF‐2 also shows significant interannual variability. To this end, we removed the seasonal signal from the dataset and recalculated EOF. We found that the interannual EOF‐1 is of cross‐shelf in spatial pattern and shows significant interannual variability. This suggests that seaward penetration of the shelf water and shelfward intrusion of the Kuroshio that mainly occur in winter and early spring are a pair of contradictions in the two‐way intrusions, which are modulated by significant interannual variability. We also found that the isopycnal extending abnormally northward and outcropping in early spring corresponds to significant non‐intrusions of the Kuroshio. In the underlying dynamics, oceanic stratification, besides topography uplifting, plays an important role in the subsurface intrusion of Kuroshio off northeast Taiwan.

Cenozoic sill intrusion in the central and southern East China Sea Shelf Basin

Cenozoic igneous rocks dominated by basalts are exposed sporadically onshore East China, and they provide important information about the Cenozoic evolution of the region. Importantly, their geometries and distribution are still not well constrained in the 200–600 km wide offshore continental shelf region. Based on seismic profiles, this study presents the geometric characteristics of 133 igneous sills that are widely distributed in the central and southern regions of the East China Sea Shelf Basin (ECSSB). Sills in high-amplitude, continuous seismic reflections mostly occur in a time interval of 1.1–3.3 s in multiple seismic profiles, corresponding to a depth range of 1.1–4.8 km. They can be classified into five types: saucer-shaped sills, strata-concordant sills, laccoliths, inclined sheets, and hybrid sills. Of these, the saucer-shaped sills predominate. Strata deformation associated with these igneous sills indicate that sill intrusion has become intense since the Miocene, and it potentially affected petroleum systems in the ECSSB. Forced folds induced by the sills are prospective petroleum traps. We infer that sill intrusion in the ECSSB was due to magma upwelling caused by dehydration and/or small-scale convection in a large mantle wedge above the stagnant Pacific slab. The subduction of the Philippine Sea plate resulted in tectonic inversion in the ECSSB and extension in the Okinawa Trough since the Early Miocene triggered more magmatism in the tectonically thinned ECSSB. Thick sedimentary strata over a thin crust in the ECSSB may have induced more intrusive than extrusive Cenozoic magmatism.

Control of strike‐slip and pull‐apart processes to tectonic transition of the southern East China Sea Shelf Basin

The East China Sea Shelf Basin (ECSSB) lies among the Eurasian Plate, the Pacific Plate, and the Indian Plate. Its formation and evolution since the Mesozoic was controlled by the combined effect of westward subduction of the Pacific Plate and actions of the large‐scale ductile shear zone on the South China Plate—the Changle–Nan'ao Fault Zone. This paper selects the southern ECSSB with well‐developed Mesozoic strata as the study area. By analysing the basin architectures and structures of each structural unit, calculating the fault growth index, and referring to the sandbox modelling results, we consider that the Oujiang Sag belongs to a strike‐slip pull‐apart basin controlled by the Changle–Nan'ao Fault Zone, while the Minjiang Sag and the Jilong Sag are extensional basins without strike‐slip property. The Mesozoic evolutionary process of the ECSSB can be divided into three stages on the basis of the three main strike‐slip movements of the fault zone. In the Middle–Late Jurassic, the subduction of the Izanagi Plate induced the dextral shearing in a ENE direction of the Changle–Nan'ao Fault Zone, which then formed NW‐SE‐directed transpressional structures inside the ECSSB. In the Late Jurassic–Early Cretaceous, the motion sense of the Izanagi Plate gradually shifted to the northwestwards, inducing the sinistral‐thrusting of the fault zone. Following this, the initial NW‐SE‐directed compressional structures were stretched into the original sag. By the Late Cretaceous, the retreat of the subducting Paleo‐Pacific Plate led to the turning of the regional stress field from compression to transtension. Being influenced by the dextral strike‐slip‐related structures of the Changle–Nan'ao Fault Zone, the Oujiang Sag developed extensive strike slipping‐related structures and was assembled into a left‐stepping en echelon pattern. The Minjiang and Jilong sags, however, gradually grew into extensional depressions under successive extension due to the great distance from the strike‐slip fault zone.

The Mesozoic Basin‐Mountain Coupling Process of the Southern East China Sea Shelf Basin and its Adjacent Land Area

Acta Geologica Sinica - English EditionVolume 90, Issue 3 p. 1051-1052 Research Advances The Mesozoic Basin-Mountain Coupling Process of the Southern East China Sea Shelf Basin and its Adjacent Land Area YANG Changqing, Corresponding Author YANG Changqing Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071 Shandong, ChinaCorresponding author. E-mail: cqyang65@163.comSearch for more papers by this authorYANG Yanqiu, YANG Yanqiu Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071 Shandong, ChinaSearch for more papers by this authorLI Gang, LI Gang Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071 Shandong, ChinaSearch for more papers by this authorYANG Chuansheng, YANG Chuansheng Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071 Shandong, ChinaSearch for more papers by this authorYANG Jinyu, YANG Jinyu Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071 Shandong, China MLR Key Laboratory of Marine Hydrocarbon Resources and Environmental Geology, Qingdao Institute of Marine Geology, Qingdao 266071 Shandong, ChinaSearch for more papers by this author YANG Changqing, Corresponding Author YANG Changqing Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071 Shandong, ChinaCorresponding author. E-mail: cqyang65@163.comSearch for more papers by this authorYANG Yanqiu, YANG Yanqiu Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071 Shandong, ChinaSearch for more papers by this authorLI Gang, LI Gang Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071 Shandong, ChinaSearch for more papers by this authorYANG Chuansheng, YANG Chuansheng Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071 Shandong, ChinaSearch for more papers by this authorYANG Jinyu, YANG Jinyu Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071 Shandong, China MLR Key Laboratory of Marine Hydrocarbon Resources and Environmental Geology, Qingdao Institute of Marine Geology, Qingdao 266071 Shandong, ChinaSearch for more papers by this author First published: 26 June 2016 https://doi.org/10.1111/1755-6724.12748Citations: 2AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume90, Issue3June 2016Pages 1051-1052 RelatedInformation

On the tectonic problems of the southern East China Sea and adjacent regions: Evidence from gravity and magnetic data

In this paper, two sets of gravity and magnetic data were used to study the tectonics of the southern East China Sea and Ryukyu trench-arc system: one data set was from the ‘Geological-geophysical map series of China Seas and adjacent areas’ database and the other was newly collected by R/V Kexue III in 2011. Magnetic and gravity data were reorganized and processed using the software MMDP, MGDP and RGIS. In addition to the description of the anomaly patterns in different areas, deep and shallow structure studies were performed by using several kinds of calculation, including a spectrum analysis, upward-continuation of the Bouguer anomaly and horizontal derivatives of the total-field magnetic anomaly. The depth of the Moho and magnetic basement were calculated. Based on the above work, several controversial tectonic problems were discussed. Compared to the shelf area and Ryukyu Arc, the Okinawa Trough has an obviously thinned crust, with the thinnest area having thickness less than 14 km in the southern part. The Taiwan-Sinzi belt, which terminates to the south by the NW-SE trending Miyako fault belt, contains the relic volcanic arc formed by the splitting of the paleo Ryukyu volcanic arc as a result of the opening of the Okinawa Trough. As an important tectonic boundary, the strike-slip type Miyako fault belt extends northwestward into the shelf area and consists of several discontinuous segments. A forearc terrace composed of an exotic terrane collided with the Ryukyu Arc following the subduction of the Philippine Sea Plate. Mesozoic strata of varying thicknesses exist beneath the Cenozoic strata in the shelf basin and significantly influence the magnetic pattern of this area. The gravity and magnetic data support the existence of a Great East China Sea, which suggests that the entire southern East China Sea shelf area was a basin in the Mesozoic without alternatively arranged uplifts and depressions, and might have extended southwestward and connected with the northern South China Sea shelf basin.

Air–sea CO<sub>2</sub> fluxes in the East China Sea based on multiple-year underway observations

Abstract. This study reports the most comprehensive data set thus far of surface seawater pCO2 (partial pressure of CO2) and the associated air–sea CO2 fluxes in a major ocean margin, the East China Sea (ECS), based on 24 surveys conducted in 2006 to 2011. We showed highly dynamic spatial variability in sea surface pCO2 in the ECS except in winter, when it ranged across a narrow band of 330 to 360 μatm. We categorized the ECS into five different domains featuring with different physics and biogeochemistry to better characterize the seasonality of the pCO2 dynamics and to better constrain the CO2 flux. The five domains are (I) the outer Changjiang estuary and Changjiang plume, (II) the Zhejiang–Fujian coast, (III) the northern ECS shelf, (IV) the middle ECS shelf, and (V) the southern ECS shelf. In spring and summer, pCO2 off the Changjiang estuary was as low as < 100 μatm, while it was up to > 400 μatm in autumn. pCO2 along the Zhejiang–Fujian coast was low in spring, summer and winter (300 to 350 μatm) but was relatively high in autumn (> 350 μatm). On the northern ECS shelf, pCO2 in summer and autumn was > 340 μatm in most areas, higher than in winter and spring. On the middle and southern ECS shelf, pCO2 in summer ranged from 380 to 400 μatm, which was higher than in other seasons (< 350 μatm). The area-weighted CO2 flux on the entire ECS shelf was −10.0 ± 2.0 in winter, −11.7 ± 3.6 in spring, −3.5 ± 4.6 in summer and −2.3 ± 3.1 mmol m−2 d−1 in autumn. It is important to note that the standard deviations in these flux ranges mostly reflect the spatial variation in pCO2 rather than the bulk uncertainty. Nevertheless, on an annual basis, the average CO2 influx into the entire ECS shelf was 6.9 ± 4.0 mmol m−2 d−1, about twice the global average in ocean margins.

Seasonal response of the southern East China Sea shelf water to wind-modulated throughflow in the Taiwan Strait

Seasonal change of the southern East China Sea (ECS) shelf water and its relation to the throughflow in the Taiwan Strait (TS) was examined based on comparative experiments with inserting passive tracers into a regional ocean model. Through analyzing the model output results, we found that from autumn to winter strong northeasterly wind over the TS significantly weakens the outflow from the TS (i.e., flowing into the ECS) and the Kuroshio water intrudes farther shoreward across the northern shelf of Taiwan in response to the weakened outflow. On the other hand, water flowing into the shelf from the TS extends further offshore from spring to summer when the TS throughflow is enhanced by a wind change from northeasterly to southwesterly and the Kuroshio water retreats seaward off the shelf due to the offshore extension of the shelf water. It suggests that the weakening (strengthening) of the TS throughflow could allow (inhibit) shelf-ward Kuroshio water onto the northeastern shelf of Taiwan, emphasizing that the throughflow modulated by a local wind can be an important factor controlling the seasonal variation of the southern ECS shelf water.

A modelling study of inter-annual variation of Kuroshio intrusion on the shelf of East China Sea

Inter-annual variability of the Kuroshio water intrusion on the shelf of East China Sea (ECS) was simulated with a nested global and Northwest Pacific ocean circulation model. The model analysis reveals the influence of the variability of Kuroshio transport east of Taiwan on the intrusion to the northeast of Taiwan: high correlation (r = 0.92) with the on-shore volume flux in the lower layer (50–200 m); low correlation (r = 0.50) with the on-shore flux in the upper layer (0–50 m). Spatial distribution of correlations between volume fluxes and sea surface height suggests that inter-annual variability of the Kuroshio flux east of Taiwan and its subsurface water intruding to the shelf lag behind the sea surface height anomalies in the central Pacific at 162°E by about 14 months, and could be related to wind-forced variation in the interior North Pacific that propagates westward as Rossby waves. The intrusion of Kuroshio surface water is also influenced by local winds. The intruding Kuroshio subsurface water causes variations of temperature and salinity of bottom waters on the southern ECS shelf. The influence of the intruding Kuroshio subsurface water extends widely from the shelf slope northeast of Taiwan northward to the central ECS near the 60 m isobath, and northeastward to the region near the 90 m isobath.

Cenozoic Tectonic Evolution and Controlling Factor on Hydrocarbon Accumulation in the Southern East China Sea Shelf Basin

The East China Sea shelf basin, which is a fault subsidence during the Cenozoic Era, locates in the East China Sea continental shelf. In this paper, balanced section technique has been applied to analyzing the differential evolution in the East China Sea shelf basin south of Cenozoic tectonic and summarizing the control factors of tectonic activities on the petroleum accumulation. Our study results will provide essential data and basis for the distribution of the Cenozoic oil and gas and promote the development of the petroleum exploration in the East China Sea shelf basin.

STRUCTURAL STYLES AND THEIR DISTRIBUTION PATTERN IN THE SOUTHERN EAST CHINA SEA SHELF BASIN

Based on regional seismic data,we studied in this paper the structural characteristics of the southern East China Sea Shelf Basin.Our results show:(1) There are three structural styles,namely extensional,compressional,and complex structures,in the study area according to their dynamic mechanism.(2)The extensional structural style can be further subdivided into the half graben,composite graben,domino faulted graben,tilting block and magmatic structures.The compressional structural style can be subdivided into compressional anticline,faulted anticline and imbricated faults.The complex structural styles can be subdivide into positive inversion tectonics and negative flower structures.

Distribution of terrigenous lipids in marine sediments off northeastern Taiwan

Surface sediments on the continental margin off northeastern Taiwan have been analyzed for terrigenous lipids including n-alkanes, n-fatty alcohols, and sterols. Marine input to the sediments is particularly low based on the average n-C17/n-C29 alkane and n-C16/n-C28 fatty alcohol ratios, 0.15±0.13 and 0.13±0.06, respectively; this may be due to the fact that marine lipids are more prone to degradation than terrestrial ones. The study area has the highest plant wax n-alkane contribution (average carbon preference index 3.9±1.2) among the coastal marine areas surrounding Taiwan; lateral particle transport from the southern East China Sea shelf and river runoff from the east Taiwan coast are considered to be the major contributors. The distributions of plant wax n-alkane and n-alkanol concentrations normalized to total organic carbon (TOC) in the study area generally show maximum values on the upper slope of the southernmost Okinawa Trough, but not for phytosterols. Linear regression of TOC versus plant wax n-alkane concentrations show a weak relationship (r=0.64, p=0.001), and an even weaker relationship (r=0.42, p=0.05) between TOC and plant wax n-fatty alcohol concentrations is found. This could be attributed to several factors: (1) a complex input (not a point source) of terrigenous organic matter to the study area, (2) TOC also including marine organic matter, (3) temporal variations in river flow due to flooding, and (4) different rates of degradation for TOC and individual biomarkers. However, in spite of those factors, TOC and phytosterol concentrations are positively linearly correlated (r=0.85, p<0.001), implying that the dilution of phytosterols in terrigenous organic carbon with marine organic carbon with or without the phytosterols follows a nearly constant ratio, which is remarkable. In addition, the predominant source of diploptene in the sediments does not appear to be of higher plant origin.

Geochemical dynamics of iodine in marginal seas: the southern East China Sea

The distributions of iodate and iodide were determined in a transect across the southern East China Sea Shelf, the upwelling center at the outer shelf-upper slope, the adjoining Kuroshio to the Okinawa Trough. In the surface waters, the variations in the concentrations of iodate and iodide among the surface waters masses, namely, the Coastal Water, the Taiwan Current Warm Water and the Kuroshio Surface Water, were relatively small. The composition of the upwelling Kuroshio Subsurface Water was distinctly different and it could be readily distinguished from the surface water masses by its elevated concentration of iodate, depressed concentration of iodide, and the resulting elevated concentration ratio of iodate to iodide. In contrast, since the variations in salinity and temperature in the surface water masses and the upwelling water were less systematic, neither salinity nor temperature could be used effectively for distinguishing these two types of water from each other. Thus, the iodine system was a complementary, or even a superior, tracer for the upwelling water. In the subsurface, the upwelling water was depicted as a dome of cold, nitrate-rich, iodate-rich and iodide-poor water, with molar ratios of iodate to iodide exceeding 10 that extended from the outer shelf-upper slope to the middle shelf. The influence of the Coastal Water was manifested as a tongue of fresher, iodide-rich and iodate-poor surface water, with molar ratios of iodate to iodide of <2.5 that extended from the inner shelf into the middle shelf. The oligotrophic Kuroshio Surface Water was also iodide-rich and iodate-poor. A box model calculation revealed that iodate was imported into the East China Sea Shelf system by frontal exchanges with the adjoining Kuroshio and upwelling at the shelf edge. Within the Shelf system, iodate was consumed and iodide was produced. As a result, during frontal exchanges between the Shelf system and the Kuroshio, there was also a net export of iodide from the Shelf system to the Kuroshio. These behaviors of the iodine system in the East China Sea Shelf system are similar to those found in the South Atlantic Bight and suggest that the marginal seas may be a preferred site for the reduction of iodate to iodide so that exchanges between the marginal seas and the open oceans may constitute a significant net source of iodide to the ocean interior.

Lateral Transport of Lithogenic Particles from the Continental Margin of the Southern East China Sea

Geochemical compositions and fluxes of suspended and trapped (settling) particulate matter were studied to elucidate particle sources and transports from the continental margin of southern East China Sea (ECS) to the Okinawa Trough. Experimental results indicate that the abundance of suspended particulate matter (SPM) and lithogenic elements (Al, Fe and Mn) decreases with an increase of distance from the land, but increases with water depth, implying the resuspension and lateral transport of SPM over the southern ECS shelf and upper slope. This transport process is further demonstrated by a decrease of mass flux from the Mien-Hwa Canyon (MHC) to the Okinawa Trough, but an increase of mass flux with depth for trapped particulate matter (TPM). In addition, mass fluxes are anomalously high and substantially greater within the MHC (6·64–71·5gm−2day−1) than nearby slope areas (0·77–15·7gm−2day−1) and other globally analogous environments. MHC appears to function as an essential conduit for particle transport. Both SPM and TPM collected below the surface layer are mainly lithogenic. Approximately 76·2–89·3% of TPM are lithogenic materials regardless of trap sites, strongly indicating that laterally lithogenic sources must add to vertical mass fluxes across the margin. Biogenic contributions are relatively small, ranging from 1·05 to 6·54% for organic matter, from 6·33 to 14·3% for carbonate and from 0·67 to 3·50% for opal, resulting from dilution by lithogenic materials. Vertical fluxes may just contribute 8–34% of Corg fluxes collected from bottom traps. Statistical correlations among Al, K, Mn, Mg and Fe contents are highly significant, also reflecting that TPM is primarily lithogenic. However, only 40–73% of collected TPM may be regarded as recent inputs from the Yangtze River. Particles resuspended and advected from shelf and/or slope may contribute significantly to TPM collected between the upper slope and the Okinawa Trough. Furthermore, short-term variabilities of mass and lithogenic fluxes on all trap occupations may arise from episodic events of resuspension/lateral transport, rather than from temporal variations of riverine inputs and local production.