550.85(084.32)(521.77)[1 50,000](083) 109 40
... 1... 5 1... 5 2... 7 2 1... 7 2 2... 10 3... 14 3 1... 14 3 2... 19 3 3... 22 4... 23... 23 1... 23 2... 24... 24 Abstract... 1
1 1 50,000 39 109 38 22 1 4 4 200m 10m 1 Mukae Michitoshi Petrography of Shionomisaki Peninsula and Oshima Island Wakayama Prefecture 1937
2 1 2 3
3 1 4
4 500m m 10m 5 7 8m 40 60m 1 4 2 3 60m 40 50m 10m 10m 40m NW-SE N-S NE-SW NE-SW 1 ENE-WSW 40 50m 60m 171.8m NW-SE N-S NE-SW 5
5 1 20 30 2 1 2 2
6 1
7 2 3 2 1 2 2 1,300m NNE-SSW NE-SW SE 10 30 NE-SW NW W 1 2 1 3
8 600 700m m 10m 30 50cm 50m siltstone 0.5 2cm 30 50cm 6
9 7 8
10 9 10 2 2 600m 2
11 11 Cyclammina sp. 10 11 10cm Vicarya? sp. Conus sp. Pecten sp. Placopecten? sp. Crassatellites cfr. namus A. ADAMS
12 Venericardia sp. Aloidis cfr. succincta YOKOYAMA 12 13
13 14 10m 10cm 1m 3
14 2 3 3 4 3 1 E-W 20 S N60 E 40 60 S 4
15 15 15 5 16 5
16 16 16 17
17 17 3cm 18
18 18
19 3 2 ENE WSW m 3m 30cm 20m 0.5 2.5m 1 20m m Nl0 W 20 E 19 cm cm 1 3m
20 19 N30 50 W 10 cm 20
21 2O 21 2 4cm 2 3m 1m 2m N-S NE NW
22 21 3 3 10cm m 22 N40 70 W 40 80 E
23 22 4 1 N5 10 W
24 2 6 22 23 21 27 14 15 1 40 136m 200m 360m 1) :20 1,, 1903 2) :,, Vol. 3, No. 4, pp. 355-369, 1938 3) :, Vol. 53, No. 622 627, pp. 67 68, 1947 4) :, Vol. 59, No. 692, pp. 215 216, 1953 5) :5 1,, 1954 6) :,, 1,, Vol.60, No. 700, 1954 6 8 1958
25 7) :5 1,, 1957 8) :,, Vol. 67, No.4, pp. 197 200, 1958 9) :5 1,, 1964
1 EXPLANATORY TEXT OF THE GEOLOGICAL MAP OF JAPAN Scale 1 : 50,000 KUSHIMOTO Kyoto, No. 109 By OSAMU HIROKAWA & ATSUYUKI MIZUNO (Written in 1964) (Abstract) GEOLOGY The mapped area lies on the southern extremity Of Kii peninsula. It is covered by middle Miocene sediments, Post-middle Miocene igneous rocks and Quaternary sediments as shown below.
2 Middle Miocene sediments The middle Miocene sediments represent a part of the lower division Koguchi formation of the Kumano group that covers the southern-southeastern part of Kii peninsula extensively. They are predominant in mudstone, attaining more than 1,300 m in thickness, and are stratigraphically divided into two members as in the other districts of the southern Kii peninsula. The Shimosato sandstone and siltstone member is composed of sandstone, mudstone and their alternation. The Shikiya siltstone member is largely composed of mudstone but in some part it intercalates a marly very fine grained sandstone, an alternation of mudstone and sandstone and also conglomerate beds. From the marly sandstone the following molluscan fossils indicating the middle Miocene age are rarely yielded : Vicarya? sp., Placopecten? sp. and Aloidis cfr. succincta (YOKOYAMA).
3 These sediments dip southeastwards in the angle of 10 whole. 30 as a Igneous rocks They consist of basic rocks, acidic rocks and a diabase of dyke form, which have been intruded or extruded in order as cited just now. Basic rocks They are metamorphosed diabase injected into the middle Miocene, hypersthene-augite gabbro, hornblende-augite gabbro diorite and olivine gabbro, graduated into each other. They have been metamorphosed by the intrusion of the acidic rocks to produce secondary minerals such as various kinds of amphibole, biotite, chlorite, epidote, zoisite, titanite, sericite and talc. Acidic rocks They are hypersthene dacite, quartz porphyry and graphic granite. The dacite is intruded into and poured out over the middle Miocene sediments. The graphic granite and quartz porphyry are intruded and permeated into the diabase and gabbro diorite, to metamorphose and enclose them at many places. The hypersthene is found in the dacite, and the biotite in the graphic granite at some places, but the mafic minerals of the acidic rocks, in general, are too altered to determine their species. Diabase of dyke form The rock in dyke form with chilled margines is intruded into either of the acidic and basic rocks in the main direction of NW-SE. It is composed of plagioclase and augite showing a graphic texture. Alluvium It is distributed in narrow areas along rivers and beaches, and consists of sand, mud and gravel.