ヨウケツ ギョウカイガン ノ フウカ ニヨル ガンセキ ブッセイ ノ ヘンカ
Rock property changes of welded tuff due to weathering
長岡, 信治 元長崎大学教育学部
Osuzu Acidic Rocks
Temporal changes in colour and physical properties due to weathering during 240 ka were examined using welded tuff gravel in fluvial terrace deposits with a known emergence time that were distributed in Miyazaki Plain, Japan. The time between the age of each terrace formation (8, 90, 120 and 240 ka) and the present was assumed to be the weathering period.
The results of the measurements are as follows: (1) effective porosity increases as the weathering period increases; (2) the a*, b*-values of colour induces increase as the weathering period increases. These results suggest that (1) the increase in pores in gravel that occurs as the weathering period increases is caused by the dissolution of biotite; (2) iron concentration and the formation of goethite occur in older gravels. Dissolution of biotite and increasing pore volume play major roles in the weathering of welded tuff.
徳島大学総合科学部自然科学研究 = Natural Science Research, The University of Tokushima
LID201312092003.pdf 1.76 MB