Reconstruction of pre-breakup Paleozoic-suture of Gondowana continent in Australia

本学年的头两个月是在新西兰和新喀里多尼亚进行实地工作的季节。通过实地考察，我们发现了澳大利亚东部拉克兰褶皱带在新西兰西海岸地区的东南延伸。然而，新英格兰褶皱带的延伸在新西兰并没有得到积极的认可。在岩石学上，新喀里多尼亚的基底与新英格兰褶皱带相似。尽管如此，测年研究并不支持上述相关性。新西兰纳尔逊Onekaka片岩的Ar-Ar和K-Ar测年研究是解决新英格兰褶皱带公认的古生代变质作用的关键。Onekaka片岩的白垩纪年龄(约100 Ma)表明，新西兰的早古生代地体只经历了白垩纪的火成岩事件。南极洲该岩石的Ar-Ar测年也显示了相同的事件。全岩Rb-Sr年龄研究和榴辉岩K-Ar年龄研究也显示了新英格兰南部褶皱带的石炭纪活动。拉克兰的放射虫研究和其他测年研究，包括U-Pb同位素研究，表明了古太平洋的第一次俯冲和随后的幕式。

The early two months of this academic year were the season for field work in New Zealand and New Caledonia. Through the field work, we recognized the south-eastern extension of the Lachlan Fold Belt, eastern Australia in the area of the west coast in New Zealand. The extension of the New England Fold Belt, however, was, not positively recognized in New Zealand. Lithologically those of basement in New Caledonia were similar to those of the New England Fold Belt. Even so, Dating study did not support the correlation mentioned above.Ar-Ar and K-Ar dating studies for the Onekaka schist, Nelson, New Zealand were keys to solve Paleozoic metamorphism which was recognized in the New England Fold Belt. The Cretaceous ages (about 100Ma) for the Onekaka schist reveals that the early Paleozoic terrain in New Zealand has suffered only Cretaceous igneous episodes.Ar-Ar dating for the rock in Antarctica also show the same episodes. Whole rock Rb-Sr age study and Eclogite K-Ar age study also show the carboniferous activity in southern New England Fold Belt. Radiolarian study in the Lachlan and other dating studies including U-Pb isotope studies indicate the first subdution and subsequence episodes in Paleo-Pacific Ocean.