Observed sediment fluxes in the southwesternmost Okinawa Trough enhanced by episodic events: flood runoff from Taiwan rivers and large earthquakes

Hsu, Shih-Chieh; Lin, Fei-Jan; Jeng, Woei‐Lih; Chung, Y.; Shaw, L.C.; Hung, Kevin

doi:10.1016/j.dsr.2004.01.009

Cited by 56 publications

(63 citation statements)

References 37 publications

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“…Some scholars believe that a large volume of sediments from eastern Taiwan Island could be transported by the KC to the southern Okinawa Trough, even dispersing further north into the middle and northern part of the trough (Hsu et al, 2004;Lee et al, 2004;Dou et al, 2012). Others, however, have demonstrated that sediments along the middle and northern slope of the trough derive mainly from the Changjiang or old Huanghe River.…”

Section: Clay Mineral and Provenance Implicationmentioning

confidence: 92%

“…Interdisciplinary studies in sedimentology, geochemistry/biogeochemistry, mineralogy and physical oceanology concur that sediments in the Okinawa Trough are mainly terrigenous; however, dispute persists concerning the sediment origin and transport mechanisms Hsu et al, 2004;Lee et al, 2004;Kao et al, 2005;Yuan et al, 2008;Bian et al, 2010;Dou et al, 2010). Some scholars believe that a large volume of sediments from eastern Taiwan Island could be transported by the KC to the southern Okinawa Trough, even dispersing further north into the middle and northern part of the trough (Hsu et al, 2004;Lee et al, 2004;Dou et al, 2012).…”

Section: Clay Mineral and Provenance Implicationmentioning

confidence: 95%

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Formation of the modern current system in the East China Sea since the early Holocene and its relationship with sea level and the monsoon system

Zheng

Wan

et al. 2015

Chin. J. Ocean. Limnol.

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The Okinawa Trough is a natural laboratory for the study of air-sea interaction and paleoenvironmental change. It has been demonstrated that present offshore export of particles in the bottom nepheloid layer occur primarily with downwelling from the northeast winter monsoon, which is inhibited by a transverse circulation pattern in summer. This current system was very different during the Last Glacial Maximum owing to low sea level (-120 m) and exposure of a large shelf area. We collected sediment core Oki01 from the middle Okinawa Trough during 2012 using R/V Kexue No . 1 to elucidate the timing and cause of the current system transition in the East China Sea. Clay mineral, dry density, and elemental (Ti, Ca) composition of core Oki01 was analyzed. The results indicate that clay minerals derived mainly from the Huanghe (Yellow) and the Changjiang (Yangtze) Rivers during 16.0-11.6 ka, and the modern current system in the East China Sea formed beginning in the early Holocene. Therefore, mixing of East China Sea continental shelf, Changjiang River and partially Taiwan Island sediment are the major contributors. The decrease of log(Ti/Ca) and alternating provenance since the early Holocene indicate less sediment from the East China in summer because of resistance of the modern current system, i.e., a "water barrier" and upwelling. Conversely, sediment delivery persists in winter and log(Ti/Ca) indicates the winter monsoon signal since the early Holocene. Our evidence also suggests that sediment from Taiwan Island could be transported by the Kuroshio Current to the middle Okinawa Trough, where it mingles with winter monsooninduced export of sediment from the Changjiang River and East China Sea continental shelf. Although the present research advances understanding of the evolutionary history of paleoenvironmental change in the Okinawa Trough, more sediment cores should be retrieved over wide areas to construct a larger scenario.

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Section: Clay Mineral and Provenance Implicationmentioning

confidence: 92%

Section: Clay Mineral and Provenance Implicationmentioning

confidence: 95%

Formation of the modern current system in the East China Sea since the early Holocene and its relationship with sea level and the monsoon system

Zheng

Wan

et al. 2015

Chin. J. Ocean. Limnol.

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“…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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“…Mineral and geochemistry indexes from adjacent core ODP1202 demonstrated that the provenance of this area was mainly the northeastern rivers of Taiwan since the Holocene [42]. Modern sedimentary dynamical observations showed that a large amount of eroded materials of Taiwan mountains was transported to the southern Okinawa Trough during the summer season [22]. In addition, a large amount of terrigenous materials was transported to the southern Okinawa Trough by the Taiwan rivers during the stronger EASM stage, which can induce stronger turbulence of the upper waters and the shallower nutricline eventually increasing the PP.…”

Section: The Impact Mechanism Of Pp Variations Of the Southern Okinawmentioning

confidence: 99%

“…ODP-1202 [12], Retreat Lake [17] and Kuroshio Current [18]. abundant summer rainfall [22]. Approximately 6-9 Mt sediments empty into the South Okinawa Trough each year through the Lanyang River of northern Taiwan.…”

Section: Study Areamentioning

confidence: 99%

Paleoproductivity variations in the southern Okinawa Trough since the middle Holocene: Calcareous nannofossil records

Zhao

et al. 2012

Chin. Sci. Bull.

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Based on 17 AMS14 C age data, we reconstructed high-resolution records of sea surface primary productivity (PP) in the southern Okinawa Trough (MD05-2908) over the last 6.8 ka BP using the calcareous nannofossil carbon isotope and the relative percentage contents of Florisphaera profunda indexes. The underlying mechanism controlling the sea surface PP was then discussed. The sea surface PP, indicated by the coccolith δ 13 C and %Fp conversional equations, decreased with some fluctuations since 6.8 ka BP. This decrease may be connected to the decreased terrigenous input resulting from the reduced East Asian Summer Monsoon (EASM) precipitation. Both the periods of 4-2 ka BP (PME) and 6.8-4.8 ka BP were characterized by relatively higher PP. The former was mainly controlled by the weakening of the Kuroshio Current, whereas the latter mainly resulted from the greater terrigenous input associated with the stronger EASM.

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Observed sediment fluxes in the southwesternmost Okinawa Trough enhanced by episodic events: flood runoff from Taiwan rivers and large earthquakes

Cited by 56 publications

References 37 publications

Formation of the modern current system in the East China Sea since the early Holocene and its relationship with sea level and the monsoon system

Formation of the modern current system in the East China Sea since the early Holocene and its relationship with sea level and the monsoon system

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

Paleoproductivity variations in the southern Okinawa Trough since the middle Holocene: Calcareous nannofossil records

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