中部中新統積成盆地形成の一形式 : 鳥取県東部地域に分布する新第三系を一例として

概要

論文の詳細を見る
The Neogene Tertiary strata, the so-called "Green Tuff" Formation, are widely distributed in the eastern part of Tottori prefecture. They are stratigraphically classified as shown in Table 1. The middle Miocene strata are divided into Entsuji sandstone and conglomerate member, and Fuganji mudstone member in ascending order. The upper formation of Lower Miocene series, i.e., Kawabara pyroclastics member, is unconformablly covered with the Middle Miocene strata at some parts, while conformablly at another parts. As the result of making reinvestigation into Entsuji sandstone and conglomerate member, some talus-like basal conglomerate beds (after San'in Green Tuff Research Group 1973) were recognized at the marginal parts of the Middle Miocene sedimentary basin. These talus-like basal conglomerate beds are composed mainly of the rock fragments derived from the basement rocks, and these rock fragments are angular and subangular in form, uneven in size. It may be hypothetically proposed that the Middle Miocene sedimentary basin resulted from depression caused by faulting, after the uneven upheavals of the early Miocene sedimentary basin and the pre-Tertiary basement complex. Furthermore, sedimentary environment of the present basin are discussed on the basis of the faunal assemblages.
日本地質学会の論文
1973-07-01