Pb-210 fluxes and sedimentation rates on the lower continental slope between Taiwan and the South Okinawa Trough

Chung, Y.; Chang, Wen Sheng

doi:10.1016/0278-4343(94)e0023-f

Cited by 67 publications

(47 citation statements)

References 20 publications

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“…For nearby areas outside of the strait (see Fig. 2b), we use previously published sediment accumulation rates derived from 210 Cs (Chung and Chang 1995;Huh and Su 1999;Lin et al 2002;Lee et al 2004) and magnetic inclination (Chen and Leu 1984); the results of which must be treated with caution due to differences in methodology. Thus, the basic assumption used to calculate the burial term is that the sedimentation pattern is steady over the last 5000 years since the sea level reached its present level (see Liu et al 2007 and references therein).…”

Section: Grain Size and Mass Accumulation Data Compilationmentioning

confidence: 99%

Sediment Budget in the Taiwan Strait with High Fluvial Sediment Inputs from Mountainous Rivers: New Observations and Synthesis

Kao¹,

Jan²,

Hsu³

et al. 2008

Terr. Atmos. Ocean. Sci.

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The shallow Taiwan Strait at the southern opening of the East China Sea (ECS) receives abundant sediments from turbid mountainous rivers in Taiwan. The volume of sediment is among the highest sediment yields on the global surface. This large amount of sediment discharged from modern Taiwan (range: 175 -380 Mt y -1 based on 50-yr data) is comparable to that discharged from Changjaing (500 Mt y -1 -decreasing in recent decades), underscoring the importance of sediment budget in the Taiwan Strait and sediment flux from Taiwan into the ECS. We documented fluvial mud and sand concentrations during flash flooding with our observations indicating that fluvial materials in Taiwan's rivers are chiefly composed of mud (> 70% and up to 98%). By contrast, sand fraction dominates (> 85% for most stations) surface sediments in the Taiwan Strait. Super typhoon Herb alone delivered 130 Mt of sediments from Choshui, the largest river in Taiwan, yet only insignificant amounts of mud were found at the river mouth six months later. The actions of waves, tides, and currents apparently prevent the deposition of fine grained sediments. Assuming sand occupied 30% (the maximum) of the 60 Mt y -1 total sediment input from major western Taiwanese rivers, our annual budget estimate shows that the amount of sand input (18 ± 5 Mt y -1 ) is comparable to the burial output of sand (12 ± 10 Mt y -1 ). However, mud burial (6 ± 5 Mt y -1 ) in the strait is far below the estimated mud input (42 ± 11 Mt y -1 ), resulting in a significant shortfall. Hydrodynamic conditions were synthesized to explain the distribution pattern of limited mud patches in the strait and to reveal potential pathways by which fine-grain sediment transportation takes place in the seas surrounding Taiwan. A significant shortfall in the mud budget in the Taiwan Strait suggests that~85% of the fluvial mud left the strait. Alternatively, the 50-year modern sediment flux data used in this study reflects exacerbated sediment flux due to human activity and is possibly too high to represent loads during pre-Anthropocene. Additional studies are needed to explore the flux and fate of mud in and surrounding Taiwan over a longer time scale.

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Section: Grain Size and Mass Accumulation Data Compilationmentioning

confidence: 99%

Sediment Budget in the Taiwan Strait with High Fluvial Sediment Inputs from Mountainous Rivers: New Observations and Synthesis

Kao¹,

Jan²,

Hsu³

et al. 2008

Terr. Atmos. Ocean. Sci.

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“…One unusual feature of the SOT is that high sedimentation rates are located approximately in the lower trough, deeper than 1000 m (ranging from 0.25 to 0.52 cm a −1 estimated from the excess 210 Pb profiles of cores) while low sedimentation rates are generally in the upper trough, shallower than 1000 m [11] . Based on results from a site 1202 (24°48.24′N, 122°30.00′E) of ODP Leg 195 in the SOT, the sedimentation rate has always been high, reaching 325 cm ka −1 (0.325 cm a −1 ) since the late Holocene [12] .…”

Section: Articlesmentioning

confidence: 99%

“…chemical characteristics, mineralogy and physical properties of the sediments. Besides the primary production in the water column [16][17][18][19] , the sediments of SOT originate from two major terrestrial sources, Chinese mainland [16,19,20] and the Taiwan hinterland [11,18,21,22] , with negligible contributions from the Ryukyu Island Arc. Nonetheless, studies conducted in the past have mainly based on surficial sediments and particles collected by sediment traps, with scant attention to the temporal variations of the provenance and transport pathways of fine-grained terrigenous sediments.…”

Section: Articlesmentioning

confidence: 99%

Sedimentation rates and provenance analysis in the Southwestern Okinawa Trough since the mid-Holocene

Jiang

et al. 2009

Sci. Bull.

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As a high-sedimentation rate depocenter along the path of the Kuroshio Current, the southwesternmost part of the Okinawa Trough is a key area to understand the Kuroshio history and sediments transportation. A 34.17-m-long sediment core was obtained by the advanced piston corer of Marco Polo/IMAGES XII MARION DUFRESNE during the May 2005 from the Southern Okinawa Trough at site MD05-2908. The recovered sediments were analyzed by AMS 14 C dating, coarse size fraction (>63 μm) extraction and moisture content determination in order to study its sedimentation flux and provenance. The depth-age relationship of core MD05-2908 was well constrained by 17 14 C dating points. The sediments span across the mid-Holocene (6.8 ka B.P.) and have remarkablely high sedimentation rates between 1.8 and 21.2 m ka −1 , which is well consistent with the modern observations from sediment traps. We identified five 70-200 a periods of abnormally rapid sedimentation events at 6790-6600 a B.P., 5690-5600 a B.P., 4820-4720 a B.P., 1090-880 a B.P., and 260-190 a B.P., during which the highest sedimentation rate is up to 21.2 m/ka. In general, the lithology of the sediments were dominated by silt and clay, associated with less than 5% coarse size fraction (>63 μm). As the most significant sediment source, the Lanyang River in northeastern Taiwan annually deliver about 10Mt materials to the coastal and offshore region of northeast Taiwan, a portion of which could be carried northward by currents toward the study area. Therefore, we concluded that the 5 abnormally rapid sedimentation events may be related to intensified rainfall in Taiwan and thus increased materials to our study area at that time. However, a few extreme-rapid sedimentation events cannot be explained by normal river runoff alone. The large earthquakes or typhoons induced hyperpycnal discharge of fluvial sediment to the ocean may also act as a potential source supply to the Okinawa Trough.

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“…Sedimentation rate was estimated from Pb-210 decay as approximately 0.25 cm/year (Chung and Chang, 1995). In contrast, Suiyo Seamount is far from the land, and the caldera floor is covered with volcanic pumice fragments and volcanic debris.…”

Section: Influences Of Sediment On the Chemical Composition Of Ore Dementioning

confidence: 99%

Chemical composition of hydrothermal ores from Mid-Okinawa Trough and Suiyo Seamount determined by neutron activation analysis

et al. 2007

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Neutron activation analysis of 13 hydrothermal ore samples (70 subsamples) collected from the Mid-Okinawa Trough and Suiyo Seamount revealed higher contents of precious metal such as Au and Ag, and those of As, Sb, Ga, and Hg than those from mid-ocean ridge hydrothermal systems. In addition, the Mid-Okinawa Trough samples were richer in Ag and Sb than those from the Suiyo Seamount. The geochemical differences among these hydrothermal ore deposits are regarded as reflecting both differences in the chemical composition of the hosted magma of hydrothermal system and the abundance of sediments that is reacted with hydrothermal fluids.

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Pb-210 fluxes and sedimentation rates on the lower continental slope between Taiwan and the South Okinawa Trough

Cited by 67 publications

References 20 publications

Sediment Budget in the Taiwan Strait with High Fluvial Sediment Inputs from Mountainous Rivers: New Observations and Synthesis

Sediment Budget in the Taiwan Strait with High Fluvial Sediment Inputs from Mountainous Rivers: New Observations and Synthesis

Sedimentation rates and provenance analysis in the Southwestern Okinawa Trough since the mid-Holocene

Chemical composition of hydrothermal ores from Mid-Okinawa Trough and Suiyo Seamount determined by neutron activation analysis

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