Biostratigraphic Study of Paleozoic and Mesozoic Groups in Central and Northern Thailand

本项目的主要目的是：1、建立泰国二叠系和下三叠系的生物地层及对比；2、泰国二叠系古生物地理的区划。在风化泥岩中发现了一些具有代表性的上二叠统有孔虫，并与上覆含氨泥岩的石灰岩相区别。邻近地区也发现了三叠纪腕足类。该地区将建立包括二叠系-三叠系界线在内的地层序列。在角三山-Phetchabun地区，中二叠统石灰岩和裸岩广泛分布，石炭系和志留系裸岩也分布在Loei-Bak Chom地区，在这些地区获得了种类丰富的化石。它们对探讨志留纪和二叠纪的古环境和古生物地理的变化是非常有用的。

The main purposes of this project are summarized as follows;1,establishment of biostratigraphy and correlation of the uppermost Permian and lower Triassic,and 2,ezamination of the Permian palaeobiogeography in Thailand.The surveyed regions are represented by three areas,namely(1),Lampang-Phayao area,(2),Kok Sam Rang-Phetchabun area,and(3),Loei-Pak Chom area.In the Lampang-Phayao area the uppermost Permian ammonoids such as Pseudogastrioceras sp.,Paratirolites sp.nov.,and Paraceltites? sp.were investigated from a weathered mudstone.In addition to them some representative Upper Permian foraminifers were also discriminated from a limestone which overlies the ammonoid-bearing mudstone.Triassic brachiopods were also investigated from a neighbouring locality.Establishment of the stratigraphic succession including the Permo- Triassic boundary will be strongly expected in this area.In the Kok Sam Rang-Phetchabun area Middle Permian limestones and nudstones widely distribute,and the Carboniferous and silurian nudstones are also distributed in the Loei-Pak Chom area.Many kinds and abundant fossils were obtained from these areas. They are very useful for discussing the change of palaeoenvironments and palaeobiogeography during Silurian and Permian.