堆積盆地の境界部に発達する断層の研究(1)

概要

論文の詳細を見る
The writers described the structure of the planeless fault and discussed its genesis, as follows: 1) The planeless faults are generally normal fault, and their throw ranges from a few millimeters to ten meters. 2) The fault breccia is completely lithified and ornamented with marks resembling to laminae of sedimentary structure along the fault planes. 3) The faults are distributed in the restricted area in which the basement of Triassic complex and Miocene flexure structure is developed. 4) The stratigraphic horizons in which the faults developed are from the Sauramachi formation (lower Miocene to middle Miocene) to the lowest Nanakita formation (upper Miocene). 5) Through the above items, the cracks of the faults were resulted from the elliptic upwarping of the basement in a certain time of the late Miocene. 6) As the angle of the contemporaneous pair cracks of faults is smaller than 45°, and as the faults are sporadical, those faults might be formed and developed under the condition of the shear stress acting from below. 7) By the Gefuge analysis of the three principal stress axes of all the pair faults (after GZOVSKY (1963)), the writers drew the stress field as Figs.10, 11.
地学団体研究会の論文
1965-01-30