Geologic and Petrologic re-examination of the "Hayachine Tectonic Belt"

重新研究了川外和龟石地区“海马赫构造带”内及周围基性-超基性岩的地层、地质结构和地球化学性质。研究结果如下：1.川西地区古生界岩石按升序划分为哈马赫杂岩(中田克蛇纹岩、卡古拉杂岩和高古拉组；奥陶系-志留系？)、牙溪川组(奥陶系-志留系)和奥达古组(志留系)。在Kamaishi地区，它被划分为Hayachine杂岩(健山杂岩和岩山杂岩；志留系？)、Senjyoataki组(泥盆系)、小川组(石炭系)和栗叶组(二叠系)。“哈马赫构造带”东缘带地质构造以逆断裂和富尔根兹向东的褶皱为特征。而西缘则以逆断层和不对称褶皱为特征，费尔根兹向西。因此，“哈马赫构造带”似乎形成了一个背斜。Hayachine杂岩的基性岩和奥长花岗岩的化学性质与大洋斜长花岗岩中的大洋玄武岩的化学性质相似。Hayachine杂岩形成于奥陶纪或志留纪洋壳，并被志留纪厚重的陆源沉积覆盖。志留纪前后，“Hayachine构造带”为被动边缘，可能是在晚侏罗世，形成了一个宽阔的背斜，与南北北上地块沿被动边缘由逆断层隔开。该背斜带被称为“海马赫构造带”。

Stratigraphy,geologic structure and geochemical nature of the basic to ultrabasic rocks in and around the "Hayachine Tectonic Belt" in the Kawai and Kamaishi district are re-examined. The results of the investigation are as follows:1. In the Kawai district, the Palaeozoic rocks are divided, in ascending order, into the Hayachine Complex (Nakadake Serpentinite, Kagura Complex and Koguro Formation; Ordovi-cian-Silurian ?), Yakushigawa Formation (Ordovician?-Silurian) and Odagoe Formation (Silurian). In the Kamaishi district, it is divided into the Hayachine Complex (Kentosan Complex and Iwakurayama Complex; Silurian ?), Senjyogataki Formation (Devonian), Kogawa Formation (Carboniferous)and Kuribayashi Formation (Permian).2. Geologic structure in the eastern marginal zone of the "Hayachine Tectonic Belt" is characterized by reverse faults and overterned folds with eastward Fergenz. On the contrary, in the western marginal zone it is characterized by reverse faults and asymmetric folds with westward Fergenz. Thus the "Hayachine Tectonic Belt" seems to form an anticlinorium.3. The chemical nature of the basic rocks and trondhjemites of the Hayachine Complex is similar to that of oceanic basalt of oceanic plagiogranite.4. The Hayachine Complex was formed as an oceanic crust in Ordovician or Silurian time, and is overlain by thick terrigenous sediments of Silurian age. On and after the Silurian, the "Hayachine Tectonic Belt" was a site of passive margin, then, probably in the late jurassic, a broad anticline was formed in the zone, which separated from the Southern and Northern Kitakami Massif by reverse faults, along the passive margin. The anticlinal zone is called the "Hayachine Tectonic Belt".