Lateral variation of phenocryst assemblages in volcanic rocks of the Japanese islands

Nature ◽  
1977 ◽  
Vol 269 (5624) ◽  
pp. 134-134 ◽  
Author(s):  
M. SAKUYAMA
Keyword(s):  
Volcanic Rocks ◽  
Lateral Variation ◽  
Japanese Islands

scholarly journals Lateral variation in 87Sr/86Sr ratios of volcanic rocks from central Japan.

1989 ◽  
Vol 23 (2) ◽  
pp. 45-55 ◽  
Author(s):  
Kenji Notsu ◽  
Yoji Arakawa ◽  
Shun Nakano ◽  
Masao Yamasaki
Keyword(s):  
Volcanic Rocks ◽  
Lateral Variation ◽  
Central Japan

scholarly journals Green-tuff landslide areas are beneficial for rice nutrition in Japan

2006 ◽  
Vol 78 (4) ◽  
pp. 749-763 ◽  
Author(s):  
Kazue Tazaki
Keyword(s):  
Microbial Mats ◽  
Volcanic Rocks ◽  
Mineral Chemistry ◽  
Mineral Surfaces ◽  
Landslide Area ◽  
Strong Earthquakes ◽  
Set Up ◽  
Main Components ◽  
Physical And Chemical ◽  
Japanese Islands

Japanese Islands are covered with weathered volcanic rocks and soils. Terraced rice field are located in green-tuff areas which are very fertile but where landslides occur associated to strong earthquakes. The Xray diffraction and X-ray fluorescence analyses of the soils in landslide area identified predominant smectite and Mg, Al, Si, K, Ti, Mn and Fe are main components. The rice leaf showed that S, Cl, K and Ca play important roles for nutrients in the area. Drainpipe systems have set up in the green- tuff areas to reduce the risks of landslides. Reddish brown microbial mats inhabited bacteria and diatom in the drainpipe outlets. The microbial mats are rich in Fe and PO4(3-). The iron bacteria in the ground water have a high metabolic rate suggesting that the weathering materials were produced by not only physical and chemical influence but also by microorganism. Many microorganisms attach to mineral surfaces and show their high impact in the water mineral chemistry in the landslide area. Bacteria in the green-tuff over landslide area play important roles for sustainable agriculture including rice nutrition.

TEM/AEM characterization of fine-grained clay minerals in very-low-grade rocks: Evaluation of contamination by empa involving celadonite family minerals

1996 ◽  
Vol 54 ◽  
pp. 694-695
Author(s):  
Gejing Li ◽  
D. R. Peacor ◽  
D. S. Coombs ◽  
Y. Kawachi
Keyword(s):  
Electron Microscopy ◽  
Volcanic Rocks ◽  
Analytical Electron Microscopy ◽  
Metamorphic Rocks ◽  
New Mineral ◽  
Chemical Compositions ◽  
Low Grade ◽  
Fine Grained ◽  
Depth Analysis ◽  
Mineral Aggregates

Recent advances in transmission electron microscopy (TEM) and analytical electron microscopy (AEM) have led to many new insights into the structural and chemical characteristics of very finegrained, optically homogeneous mineral aggregates in sedimentary and very low-grade metamorphic rocks. Chemical compositions obtained by electron microprobe analysis (EMPA) on such materials have been shown by TEM/AEM to result from beam overlap on contaminant phases on a scale below resolution of EMPA, which in turn can lead to errors in interpretation and determination of formation conditions. Here we present an in-depth analysis of the relation between AEM and EMPA data, which leads also to the definition of new mineral phases, and demonstrate the resolution power of AEM relative to EMPA in investigations of very fine-grained mineral aggregates in sedimentary and very low-grade metamorphic rocks.Celadonite, having end-member composition KMgFe3+Si4O10(OH)2, and with minor substitution of Fe2+ for Mg and Al for Fe3+ on octahedral sites, is a fine-grained mica widespread in volcanic rocks and volcaniclastic sediments which have undergone low-temperature alteration in the oceanic crust and in burial metamorphic sequences.

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