Geological Studies on the Mobile Belts of Asian-Pacific Ocean Region, Especially Tectonics of the South Island of New Zealand

这是一份关于新西兰南岛奥塔哥海岸部分研究联合项目的报告。项目名称为“高知大学-奥塔哥大学联合研究吸积复杂地质：奥塔哥海岸剖面”。这项实地工作于1990年9月至10月进行。本研究的主要目的是在亚太地区活动带的框架下，比较新西兰南岛与日本西南外带的增生过程，阐明其地质构造发育的构造史。本研究采用的方法如下：(1)沿达尼丁西南Chrystalls Beach地区海岸线构造图的构建。(2)收集含微化石的岩石标本进行放射虫生物地层研究；(3)收集典型岩石标本进行岩石学和岩石化学研究；(4)综合研究区所有新的地质和岩石学资料。以下几点对准备未来的报告和论文发表感兴趣，(1)凝灰质成分：玄武质透明质碎屑可能存在于枕状-熔岩变质岩组合中。更有问题的是硅质灰对樱桃质沉积物的体积贡献，特别是对浅灰色、绿灰色和粉红色泥质沉积的体积贡献。有充分的证据表明，有几厘米厚的分级灰层，伴随着玻璃碎片向上延伸。(2)克里斯托斯海滩复合体的地体亲缘性：过去，许多研究人员倾向于认为克里斯托斯海滩复合体是凯普斯地体的一部分。然而，我们的一些岩石学研究表明，水晶滩杂岩的变质砂岩中碎屑石英、斜长石和钾长石的相对比例，特别是石英的优势和火山岩屑碎片的稀疏性，与凯普斯地体的已知单元有很大不同。与枕状玄武岩、燧石和浅色泥质岩的关联更适合于Torlesse或Aspiring而不是capples。(3)磷化结核：存在两种类型的磷化结核。一个含有或多或少丰度的放射虫和极少量的陆源碎屑。另一种类型含有丰富的淤泥或细砂颗粒。由于第一种类型中没有陆源碎屑，我们怀疑它们一定是在浊积岩沉积暂停期间在海底形成的地壳，(4)渗透变形，(5)K-Ar测年。少

This note is a report of a research joint project on the Otago coast section in the South Island, New Zealand. The title of the project is "Kochi University-Otago University Joint Study of Accretion Complex Geology : Otago Coast Section". This field work was carried out from September to October, 1990. The main purpose of this study is to compare the accretionary process of the South Island in New Zealand with that of the Outer Zone of Southwest Japan in the framework of the mobile belts of Asian-Pacific Ocean regions and to elucidate tectonic histories of development of their geological structures.The methods applied in this study were as follows :(1) Construction of structural map along the coastline of the Chrystalls Beach area, southwest of Dunedin.(2) Collection of microfossil-bearing rock specimens to investigate radiolarian biostratigraphy,(3) Collection of typical rock specimens and investigation of their petrography and petrochemistry, and(4) Synthesis of all new data on the g … More eology and petrology of the study area.Following points are interested in the preparation of future reports and papers for publication arising from our project,(1) Tuffaceous component : Basaltic hyaloclastites may be present in the pillow-lava metabasite association. Much more problematic is the volumetric contribution of more siliceous ash to the cherty sediments and especially to the pale gray, greenish gray, and pink shaly metasediments. There is good evidence for graded ash beds, a few centimeters thick, accompanied and followed upwards by glass shards. These no doubt originated from distant plinian eruptions in the acid andesite to ryolite composition range,(2) Terrane affinities of the Chrystalls Beach Complex : Various workers have tended to assume in the past that the Chrystalls Beach complex is part of the Caples terrane. Nevertheless as shown by some of our petrological study, the relative proportions of detrital quartz, Plagioclase, and K-feldspar, and in particular the dominance of quartz and sparsity of volcanic lithic fragments in the metasandstones of the Chrystalls Beach Complex, are very different from those in known units in the Caples terrane. The association with pillow basalts, cherts, and light-coloured shaly rocks fits better with Torlesse or Aspiring than with Caples,(3) Phosphatic nodules : Two types of phosphatic nodules are present. One contains radiolaria in greater or less abundance, and extremely little terrigenous detritus. The other type contains abundant silt or fine sand grains. From the absence of terrigenous detritus in the first type, we suspect they must form as a crust on the sea floor during pauses in turbidite sedimentation,(4) Penetrative deformation, and (5) K-Ar dating. Less