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

• Project/Area Number: 02041063
• Research Category: Grant-in-Aid for international Scientific Research
• Allocation Type: Single-year Grants
• Section: Field Research
• Research Institution: Kochi University
• Principal Investigator: SUZUKI Takashi Department of Geology, Kochi University, Professor, 理学部, 教授 (20036528); 鈴木 堯士 高知大学, 理学部, 教授
• Co-Investigator(Kenkyū-buntansha): AITCHISON J. C. Department of Geology and Geophysics, Sydney University, Australia, 理学部(オーストラリア), 講師 ; LANDIS C. A. Geology Department, Otago University, New Zealand, 理学部(ニュージーランド), 助教授 ; COOMBS D. S. Geology Department, Otago University, New Zealand, 理学部(ニュージーランド), 教授 ; MAEJIMA Akira Department of Geology, Osaka City University, Lecturer, 理学部, 助手 (20173700) ; YOSHIKURA Shinーichi Department of Geology, Kochi University, Ass. Professor, 理学部, 助教授 (10093957) ; SUZUKI Morihisa Department of Education, Hiroshima University, Ass. Professor, 学校教育学部, 助教授 (10033888) ; HADA Shigeki Department of Geology, Kochi University, Professor, 理学部, 教授 (40036554)
• Project Period (FY): 1990
• Project Status: Completed (Fiscal Year 1990)
• Budget Amount: ¥10,000,000 (Direct Cost: ¥10,000,000); Fiscal Year 1990: ¥10,000,000 (Direct Cost: ¥10,000,000)
• Keywords: South Island / New Zealand / Caples terrane / Torlesse terrane / radiolarian fossils melange / geochemistry of greenstones

Research Abstract

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 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.

Research Products

• [Publications] SUZUKI,T.,COOMBS,D.ET AL.: "Geology and structure of the Chrystalls Beach Complex,in the South Island,New Zealand,with special reference to the question of the title to the complex."
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] HADA,S.,LANDIS,C.ET AL.: "Mesozoic radiolarian ages of the Chrystalls Beach Complex,South Island,New Zealand." Geology.
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Suzuki, T. , Coombs, D. et al.: "Geology and structure of the Chrystalls Beach complex, in the South Island, New Zealand, with special reference to the question of the title to the complex."
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] Hada, S. , Landis, C. et al.: "Mesozoic radiolarian ages of the Chrystalls Beach Complex, South Island, New Zealand." Geology.
  • Description: 「研究成果報告書概要(欧文)」より