Greenstone and terrigeous clastics in the Hidaka Supergroup, northern Hokkaido

通过研究，我取得了以下研究成果。鲁罗奇组。它发生在北海道的北部。主要由黑色页岩、砂岩和蜗牛岩交替层和绿岩组成。地层中含有黑色页岩和奇异的绿色硅质页岩区块，产生始新世放射虫组合。绿岩由块状玄武岩、枕状玄武岩和基性凝灰岩组成。玄武岩经常侵入黑色页岩中。玄武岩的玻璃冷却边缘和黑色页岩的烘焙部分证实了这些火成岩接触的主要性质。玄武岩中的泥质包体和枕间黑色页岩的枕状熔岩也很常见。Makimine组主要由泥质岩和绿岩组成。绿岩包括玄武岩、块状玄武岩、枕状玄武岩和基性凝灰岩。一些双冷边厚度不到几厘米的辉绿岩岩床与黑色页岩夹层。在大多数情况下，由于榴辉岩侵位的热效应，黑色页岩在距离榴辉岩接触点几厘米的范围内显示出向浅色烘焙岩石的渐变。-榴辉岩通常含有黑色页岩包体。这些事实表明，玄武岩侵入并挤出了松散的细粒碎屑沉积。木吉组以泥质岩和绿岩为代表。一些边缘冷却的玄武岩熔岩与黑色页岩直接接触，黑色页岩在接触过程中局部遭受了热效应。黑色页岩包体局部赋存于玄武岩中。地层中的玄武岩是根据其化学特征在扩张山脊上形成的。因此，在这种情况下，我们得出结论，绿岩的侵位与山脊-弧前碰撞有关。

I have gained the following results through the research.1). The Rurochi Formation. which occurs in the northern part of Hokkaido. consists mainly of black shale, alternating beds of sandstone and snale, and greenstones. Black shale and exotic blocks of green siliceous shale withi in the formation yield Eocene radiolarian assemblages. The greenstones are composed of massive basalt, pillow basalt and basic tuff. Basalts have been intruded frequently into black shale. Glassy chilled margins of basalt and baked parts of black shale confirm the primary nature of these igneous contacts. Argillaceous xenoliths in the basaltic rock, and pillow lavas with inter-pillow black shale are also common.2). The Makimine Formation is made mainly up argillite and greenstones. The greenstones comprise dolerite, massive basalt, pillow basalt and basic tuff. Some dolerite sills with double chilled margins less than a few centimeters in thickness are interlayered with black shale. In most cases the black shale shows gradational alteration to light-colored baked rock over a range of a few centimeters from dolerite contacts, due to the thermal effect of dolerite emplacement. - Dolerites commonly contain xenoliths of black shale. These facts indicate that the basaltic rocks were intruded into and extruded upon unconsolidated fine-grained clastic sediments.3). The Mugi Formation is represented by argillite and greenstones. Some of the basalt lavas with chilled margins are in immediate contact with black shale, which has locally suffered thermal effects along its contact. Xenoliths of black shale occur locally in the basalts.4). The basaltic rocks in the formations were generated at a spreading ridge on the basis of their chemical features. In this context, we therefore conclude that the greenstones were emplaced in connection with a ridge-forearc collision.