Middle Triassic Radiolarians from Cherts/Siliceous Shales in an Extensional Basin in the Sukhothai Fold Belt,Northern Thailand  

作　　者：Hathaithip Thassanapak Mongkol Udchachon Qinglai Feng Clive Burrett 

机构地区：[1]Applied Paleontology and Biostratigraphy Research Unit, Department of Biology, Faculty of Science, Mahasarakham University, Mahasarakham 44150, Thailand [2]State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074, China [3]Paleontological Research and Education Center, Mahasarakham University, Mahasarakham 44150, Thailand [4]School of Physical Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia

出　　处：《Journal of Earth Science》2017年第1期9-28,共20页地球科学学刊（英文版）

基　　金：supported by the National Natural Science Foundation of China (No.41672222);the National Postdoctoral Program for Innovative Talents (No.BX201600194);Mahasarakham University

摘　　要：More than thirty species of radiolarians are described from maroon chert and siliceous shales from the Den Chai and Santisuk sections in the east of the Sukhothai fold belt. The fauna obtained from Den Chai comprises Muelleritortis cochleata cochleata, M. cochleata tumidospina, M. expansa, Triassocampe deweveri, T. coronata, T. scalaris, Annulotriassocampe companilis, A. multisegmantatus, A. sulovensis, Pseudostylosphaera coccostyla coccostyla, P. imperspicua, Canoptum inornatus, C. levis, Corum kraineri, Spongoserrula rarauana, Orbiculiforma karnica and others. The assemblage may be correlated with those reported in the Fang-Chiang Dao and Lumphun areas in the north of Thailand and in the ChangningMenglian belt of western Yunnan, South China and suggests a late Ladinian（Middle Triassic） age. The radiolarian fauna from the Santisuk Section comprises Muelleritortis cochleata cochleata, M. sp., Striatotrissocampe nodosoannulata, Triassocampe. deweveri, T. sp., Pseudogodia？ sp., Pseudostylosphaera coccostyla coccostyla, Archaeocenosphera sp., Annulotriassocampe multisegmantis, Pseudostylosphaera sp., and others which indicates a late Ladinian age. Middle Triassic radiolarian chert and siliceous shale from Den Chai and Santisuk are interpreted as having been deposited in an extensional continental margin within the Sukhothai fold belt and not in the Devonian–Permian back-arc basin of the Nan suture. These deep marine sequences were deposited in a subsiding continental margin in the Lampang-Phrae Basin. We consider these sequences to be part of the Hong Hoi Formation（Anisian–Ladinian） of the Lampang Group which, in turn, may be compared to the Choushui Formation and other associated Middle Triassic formations in the Simao Basin of South China.More than thirty species of radiolarians are described from maroon chert and siliceous shales from the Den Chai and Santisuk sections in the east of the Sukhothai fold belt. The fauna obtained from Den Chai comprises Muelleritortis cochleata cochleata, M. cochleata tumidospina, M. expansa, Triassocampe deweveri, T. coronata, T. scalaris, Annulotriassocampe companilis, A. multisegmantatus, A. sulovensis, Pseudostylosphaera coccostyla coccostyla, P. imperspicua, Canoptum inornatus, C. levis, Corum kraineri, Spongoserrula rarauana, Orbiculiforma karnica and others. The assemblage may be correlated with those reported in the Fang-Chiang Dao and Lumphun areas in the north of Thailand and in the ChangningMenglian belt of western Yunnan, South China and suggests a late Ladinian（Middle Triassic） age. The radiolarian fauna from the Santisuk Section comprises Muelleritortis cochleata cochleata, M. sp., Striatotrissocampe nodosoannulata, Triassocampe. deweveri, T. sp., Pseudogodia？ sp., Pseudostylosphaera coccostyla coccostyla, Archaeocenosphera sp., Annulotriassocampe multisegmantis, Pseudostylosphaera sp., and others which indicates a late Ladinian age. Middle Triassic radiolarian chert and siliceous shale from Den Chai and Santisuk are interpreted as having been deposited in an extensional continental margin within the Sukhothai fold belt and not in the Devonian–Permian back-arc basin of the Nan suture. These deep marine sequences were deposited in a subsiding continental margin in the Lampang-Phrae Basin. We consider these sequences to be part of the Hong Hoi Formation（Anisian–Ladinian） of the Lampang Group which, in turn, may be compared to the Choushui Formation and other associated Middle Triassic formations in the Simao Basin of South China.

关 键 词：TRIASSIC RADIOLARIANS Sukhothai fold belt Nan suture Thailand. 

分 类 号：Q915[天文地球—古生物学与地层学] P534.51[生物学—古生物学]