Regional spatial distribution of multiple elements in the surface sediments of the eastern Tsushima Strait (southwestern Sea of Japan)

Ohta, Atsuyuki; Imai, Noboru; Terashima, Shigeru; Tachibana, Yoshiko; Ikehara, Ken

doi:10.1016/j.apgeochem.2013.06.010

Cited by 12 publications

(5 citation statements)

References 27 publications

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“…Data processing by GDAL followed by geo-visualization in GRASS GIS, presented in this paper, aimed at topographic modelling for regional physical geographical analysis in the area of the Okinawa Trough and Ryukyu trencharc system. Such methodology has not been qualitatively explored in the existing papers, despite some thematic overlaps (Ohta et al, 2013;Minami and Ohara, 2020;Arai et al, 2016a;Minami et al, 2020;Li et al, 20201;Xu and Chen, 2021).…”

Section: Introductionmentioning

confidence: 99%

Okinawa Trough geophysical and topographic modeling by GDAL utilities and GRASS GIS

Lemenkova

2021

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This paper presents using GDAL utilities and GRASS GIS for topographic analysis of the raster grids based on GEBCO DEM as NetCDF file at 15 arc-second intervals. The focus study area encompasses the area around Okinawa Trough, Ryukyu trench-arc system, southern Japan, East China Sea and the Philippine Sea, West Pacific Ocean. Several GDAL utilities were applied for data processing: gdaldem, gdalwarp, gdalinfo, gdal_translate. The data were imported to GRASS GIS via r.in.gdal. Data visualization highlighted high resolution and accuracy of GEBCO grid, enabling topographic modelling at the advanced level. The algorithm of DEM processing, implemented in GDAL utility gdaldem, was used for generating multi-purpose topographic models: aspect, hillshade, roughness and topographic indices, such as Topographic Position Index (TPI), Terrain Ruggedness Index (TRI). Thematic maps (topography, geoid, marine free-air gravity) were visualized using GRASS GIS modules for raster (d.rast, r.colors, r.contour) and vector (d.vect, v.in.region, d.legend) data processing. The results demonstrated smoother bathymetry in the East China Sea and rugged relief in the Philippine Sea which corresponds to their different geological and geophysical settings. The presented methodology of the topographic analysis based on DEM demonstrated technical aspects of GDAL and GRASS as scripting approach of advanced cartography.

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Section: Introductionmentioning

confidence: 99%

Okinawa Trough geophysical and topographic modeling by GDAL utilities and GRASS GIS

Lemenkova

2021

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“…The analytical methods and quality control of the geochemical data have been described by Imai (1990), Ujiie-Mikoshiba et al (2006), and Ohta et al (2013). Each sample was digested for 2 h using a mixed solution of HF, HNO 3 and HClO 4 at 120°C.…”

Section: Methodsmentioning

confidence: 99%

“…We conducted the first comprehensive survey of elemental distributions in both terrestrial and marine environments because Japan is surrounded by seas. Previously, we have established a procedure for multi-elemental analysis of geochemical mapping data sets (Ohta et al, 2007) and proposed its application in investigating particle transportation processes from land to sea and within marine environments , as well in provenance study of marine sediments (Ohta et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Influence of different sedimentary environments on multi-elemental marine geochemical maps of the Pacific Ocean and Sea of Japan, Tohoku region

Ohta

Imai

Tachibana

et al. 2017

Bull. Geol. Surv. Japan

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(2017) Influence of different sedimentary environments on multi-elemental marine geochemical maps of the Pacific Ocean and Sea of Japan, Tohoku region. Bull. Geol. Surv. Japan, vol. 68 (3), p. 87-110, 9 figs, 5 tables. Abstract:The authors present comprehensive terrestrial and marine geochemical maps of the Tohoku region and examine how marine sedimentary environments affect the spatial distribution of elemental concentrations. Marine sediments from the Sea of Japan are relatively enriched in elements abundant in felsic igneous rocks such as K 2 O, Ba, and REEs. These elements are highly enriched in sediments around submarine topographic highs, and are products of the denudation of Neogene sedimentary rocks associated with dacitic tuff and barite nodules. The silt and clay in deep basins are abundant in elements such as MnO, Cd, and Pb because of early diagenetic processes. Silty sediments on the continental shelf are supplied by large rivers; however, their geochemical features are influenced not by the adjacent terrestrial materials but simply by the effects of grain size. The sandy sediments that extensively cover the seafloor of the Pacific Ocean in the study area were sampled from depths below wave base (100 -1,000 m). Their chemical compositions are homogenous and similar to those of stream sediments that originate from mafic volcanic rocks. Therefore, they are inferred to have been deposited as relict sediments under the influence of Quaternary mafic volcanic activity that have been transported from the shelf to the deep sea by gravity currents. Although 81% of the total terrestrial sediment yield is discharged into the Sea of Japan, the spatial distributions of elemental concentrations are not always continuous between land and sea. Similar findings are recognized for the Pacific Ocean side. Notably, coarse sands distributed offshore from Kamaishi are enriched in elements abundant in sedimentary rocks of the accretionary complexes and granitic rocks that crop out in adjacent terrestrial areas. Because the river system in this region is small and has low sediment yields, these coarse sands may have been produced via coastal erosion or denudation of parent rocks during past regression and transgression.

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“…The analytical method including quality control has been described in Ohta et al (2013). First, 0.2 g of each sample was digested for 2 h using HF, HNO 3 , and HClO 4 solutions at 120°C.…”

Section: Geochemical Analysismentioning

confidence: 99%

“…However, Ohta et al (2013) In this study, we selected the area around Oki Trough bordered on the east by the eastern Tsushima Strait. The submarine geology in the area has been examined using seismic reflection profiles as described the follow by Ikehara et al (1990b), Yamamoto (1991), and Yamamoto (1993).…”

Section: Introductionmentioning

confidence: 99%

Elemental distribution of surface sediments around Oki Trough including adjacent terrestrial area: Strong impact of Japan Sea Proper Water on silty and clayey sediments

Ohta

Imai

Terashima

et al. 2015

Bull. Geol. Surv. Japan

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Four-hundred sixty marine sediment samples were collected in the western Sea of Japan and analyzed for 53 elements for a marine geochemical mapping project associated with a nationwide terrestrial geochemical map. Grain size and chemical compositions of marine sediments vary significantly with location of origin (shelf, marginal terrace, slope, or basin). Sandy sediments distributed on the shelf do not likely reflect the geochemical features of river sediments, which are the dominant source of sands in the shelf. Most of the shelf sediments sampled are composed of relict sediments (little contribution of stream sediments) formed between the regression age and the transgression age because they contain a large amount of quartz coated by iron hydroxide and highly enriched in As. The marginal terrace is covered by modern silty sediments that are selectively deposited at the water mass boundary between Tsushima Current (surface water) and Japan Sea Proper Water (deep water). Silty sediments in the western portion of marginal terrace are highly enriched in Nb, rare earth elements, Ta, and Th, which are supplied from Quaternary alkaline volcanic rocks by a denudation process. They are carried eastward by as much as 200 km by oceanic currents. In contrast, the eastern marginal terrace is covered by silty sediments that are highly abundant in Cu, Zn, and Hg, which is attributed to biogenic remains in sediments (organic complex formation). Clayey sediments are widely distributed in the Oki Trough and basin where a hemipelagic environment and highly oxic conditions are found because of the influence of Japan Sea Proper Water. A thin Mn oxide layer in the uppermost 0-4 cm and extreme enrichment of V, Co, Ni, Mo, Sb, and Pb would be caused by an early diagenetic process. Thus, the spatial distribution patterns of elements in marine sediments in the study area are strongly controlled by their depositional environments.

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Regional spatial distribution of multiple elements in the surface sediments of the eastern Tsushima Strait (southwestern Sea of Japan)

Cited by 12 publications

References 27 publications

Okinawa Trough geophysical and topographic modeling by GDAL utilities and GRASS GIS

Okinawa Trough geophysical and topographic modeling by GDAL utilities and GRASS GIS

Influence of different sedimentary environments on multi-elemental marine geochemical maps of the Pacific Ocean and Sea of Japan, Tohoku region

Elemental distribution of surface sediments around Oki Trough including adjacent terrestrial area: Strong impact of Japan Sea Proper Water on silty and clayey sediments

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