scholarly journals Discovery of an early Middle Pleistocene marker tephra around the Ariake Bay area, Southwest Japan

2012 ◽  
Vol 118 (11) ◽  
pp. 709-722 ◽  
Author(s):  
Shoichi Shimoyama ◽  
Hirohisa Matsuura ◽  
Kiyohide Mizuno ◽  
Masakazu Kubota ◽  
Takenori Hino ◽  
...  
Keyword(s):  
Middle Pleistocene ◽  
Ariake Bay ◽  
Southwest Japan ◽  
Bay Area

scholarly journals Quick Clay Development and Cation Composition of Pore Water in Marine Sediments from the Ariake Bay Area, Japan

2014 ◽  
Vol 05 (06) ◽  
pp. 595-606 ◽  
Author(s):  
Phanny He ◽  
Masami Ohtsubo ◽  
Hiroshi Abe ◽  
Takahiro Higashi ◽  
Motohei Kanayama
Keyword(s):  
Pore Water ◽  
Marine Sediments ◽  
Ariake Bay ◽  
Cation Composition ◽  
Bay Area ◽  
Quick Clay

scholarly journals Age and Sedimentary Environment of Newly Discovered Middle Pleistocene Marine Deposits beneath the Northern Coast Region of Ariake Bay, Kyushu, Japan

2013 ◽  
Vol 122 (5) ◽  
pp. 841-853
Author(s):  
Keitaro YAMADA ◽  
Takenori HINO ◽  
Shoichi SHIMOYAMA ◽  
Keiji TAKEMURA ◽  
Tohru DANHARA ◽  
...  
Keyword(s):  
Sedimentary Environment ◽  
Middle Pleistocene ◽  
Northern Coast ◽  
Ariake Bay ◽  
Marine Deposits ◽  
Coast Region

Properties of a low-swelling smectitic marine clay of interest in soil engineering

1985 ◽  
Vol 22 (2) ◽  
pp. 241-245 ◽  
Author(s):  
Masami Ohtsubo ◽  
Kazuhiko Egashira ◽  
Masateru Takayama
Keyword(s):  
Paddy Soil ◽  
Swelling Pressure ◽  
Ariake Bay ◽  
Marine Clay ◽  
Swelling Properties ◽  
Air Drying ◽  
Swelling Clay ◽  
Bay Area ◽  
Nacl Concentration ◽  
Marine Clays

Smectite is generally a high-swelling clay. However, the smectite found in marine quick clays in the Ariake Bay area of Japan is a low-swelling clay like illite and kaolinite. The low swelling properties of an Ariake marine clay are investigated here in terms of consolidation, swelling, and shrinkage characteristics. The void ratios in compression curves of soils containing sodium are lower at 0.01 N than at 1.0 N NaCl concentration, and the slopes of swelling curves are independent of salt concentration in the pore water and cation valency. These tendencies are contrary to those observed for montmorillonite and a paddy soil containing high-swelling smectite. Measurements of swelling pressure suggest that the smectite in the Ariake marine clay exhibits little intracrystalline swelling even after saturation with Na. The volume shrinkage of the Ariake marine clay by air-drying is smaller than that of the paddy soil. Key words: compressibility, marine clays, smectite, swelling.

Bed-thickness frequency distributions and recurrence intervals of sediment-gravity-flow deposits intercalated in lacustrine varved diatomite: examples from the middle Pleistocene Hiruzenbara Formation, southwest Japan

2020 ◽  
Vol 90 (6) ◽  
pp. 561-572
Author(s):  
Hana Sasaki ◽  
Yasunori Sasaki ◽  
Megumi Saito-Kato ◽  
Hajime Naruse ◽  
Yoshiro Ishihara
Keyword(s):  
Power Law ◽  
Slope Failure ◽  
Gravity Flow ◽  
Middle Pleistocene ◽  
Southwest Japan ◽  
Frequency Distributions ◽  
Base Section ◽  
Sediment Gravity Flow ◽  
Recurrence Intervals ◽  
Bed Thickness

ABSTRACT Bed-thickness frequency distributions of sediment-gravity-flow deposits, especially turbidites, are one of the major interests of sedimentology. Lognormal, power-law, exponential, and truncated normal distributions have all been proposed for their frequency distributions. Although these frequency distributions have been obtained from many field observations and estimated from statistical models, problems associated with the complexity of sedimentary processes have remained. In this study, bed-thickness frequency distributions and the recurrence intervals of sediment-gravity-flow deposits intercalated in the Pleistocene lacustrine varved diatomite in southwest Japan were analyzed. The results reveal that the bed thicknesses of sediment-gravity-flow deposits induced by different mechanisms show different types of frequency distribution. For example, flood-induced sediment-gravity-flow deposits show power-law-like distributions, whereas such deposits caused by lake-slope-failure show lognormal distributions. The suggestion is that flood-induced types are deposited from floods having a power-law scale. However, the bed thicknesses of the deposits induced by lake-slope-failure do not purely reflect the event scale, because the lateral variation of their thicknesses reflects the depositional processes. The recurrence intervals of both types of event show Poisson-like distributions except for lake-slope-failure deposits at the slope-base section. Despite observed ranges, the distributions of lake-slope-failure deposits at the slope-base section have a high amount of zero value and the recurrence interval show exponentially decreasing. These results suggest that both events were generated randomly, despite different origins. In addition, the incompleteness of the records was also suggested from sediment bypass of a lake-slope-failure event at the slope-base section.

Sensitivity of Salt-leached Clay Sediments in the Ariake Bay Area, Japan

2014 ◽  
Vol 33 (5) ◽  
pp. 429-436 ◽  
Author(s):  
Phanny He ◽  
Masami Ohtsubo ◽  
Takahiro Higashi ◽  
Motohei Kanayama
Keyword(s):  
Ariake Bay ◽  
Bay Area
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