鳥取温泉におけるボーリング･コアの組成鉱物について

鳥取温泉の深度300mに及ぶ試錐のボーリング･コアを検討した結果,主成分鉱物として,石英,長石類(斜長石,加里長石,)と二次的生成鉱物としてモンモリロナイト,カオリナイト,イライト,緑泥石,黄鉄鉱などを認めた.このうち,イライトは堆積岩中に普遍的に存在し,更に緑泥石も全般的にしかも第三紀層で多量に認められている.モンモリロナイトは方解石と共に温泉による生成が考へられ,また,カオリナイトは表土層にのみ認める事ができる.一方,加里長石,黄鉄鉱,緑泥石の産出状態,及びコアが示す粒度,酸化状態からして第四紀層の堆積環境が推定され,25mを境として下部は数回の陸化を含む浅い堆積層であるのに対し,上部は比較的深い.背後供給地から離れた海成層を示唆する.

The boring coreS of Tottori Hot Spring, Tottori city were investigated by means of X-ray powder method and differential thermal analysis. Near this district, the Quarternary sediments are perceived until at a depth of 54 meters, and they show some striking differences from the Tertiary sediments which lies under-neath the former. In the Quarternary sediments, small amounts of chlorite coexist with ilIte. Kaolinite is found only in the top soil, and montmorillonite is present just above the unconformity with the Tertiary sediments. The clays from the Tertiary sediments contain abundant amounts of chlorite that exibits regional propylitization. The amounts of the rock forming minerals, quartz and feldspars, in these sediments regularly decrease with increasing amounts of clay minerals. The pH of the thermal water at the pit bottom ranges from 7 to 8, and the maximum water temperature, 57.2℃, is observed. The secondary minerals, montmorillonite and calcite, are thought to be the alteration products by the thermal water.

Original Papers