撣泰地體

撣泰地塊,又稱撣邦地塊、滇緬馬蘇地塊(Sibumasu massif)、滇緬馬來亞地塊(Sinoburmalaya massif),中國境內稱為保山地塊。位於緬甸東部撣邦的一個近南北向的長條形地體。北起中國雲南保山,向南經過緬甸、泰國、馬來半島,南至蘇門答臘島,長4000km。[1]

概述

西側以實皆斷裂緬甸中央盆地相鄰;東側以一個較寬的印支期造山帶印支地塊東馬來地塊分開。

地塊基底僅出露於滇西和緬甸,在滇西稱為公養河群,在緬甸稱為昌馬支超群,為一套砂泥質變質岩系。公養河群被含化石的上寒武統整合覆蓋,而昌馬支超群則與上寒武統不整合覆蓋。蓋層從上寒武統一直延續到三疊系,基本上是連續沉積,其上有少量侏羅、白堊紀紅層。蓋層的石炭、二疊紀沉積中含有冰水沉積和冷水動物群化石,說明本地塊原本是岡瓦納大陸的一部分。晚古生代二疊紀末從東岡瓦納分離出來[2],向北漂移,三疊紀末與印支地塊碰撞[3],成為歐亞板塊的一部分。

撣泰地塊在古特提斯洋中是一個跨越幾個維度的列島。因而可以分為幾部分,具有不同的古地理歷史。

已隱藏部分未翻譯內容,歡迎參與翻譯
"Thai" elements, bordering the Indochina block, are of 華夏古陸n type and characterised by palaeo-tropical warm-water 沉積相. The external "Shan" part has Gondwanan cold-water facies whilst the central "Sibumasu" part is transitional between the other two.

The internal parts of Shan–Thai merged with Laurasia 265 Ma when the Nan-Uttaradit suture closed.[4] Oceanic basins separated the other elements of Shan–Thai until the Late Triassic–Early Jurassic Late Indochina Orogeny.[5]

The collision between India and Eurasia during the Oligocene and Miocene resulted in clockwise rotation of south-west Asia, severe deformation of south-east Asia, and the extrusion of Shan–Thai and Indochina blocks. These two blocks are still crisscrossed by the faults from this collision.[6]

參考文獻

  1. ^ Chaodumrong, Xiangdong & Shuzhong 2007: "Permian strate of the Shan-Thai terrance in Thailand consist of the clastic sequence of the Kaeng Krachon Group and the conformably overlying carbonate sequence of the Ratburi Group ...[which] can be traced widely from Malaysia, through peninsular Thailand, Myanmar, West Yunnan, to Lhasa."
  2. ^ Fortey & Cocks 1998,Introduction, pp. 43-44
  3. ^ Bunopas & Vella 1992: "Thailand consists of Shan–Thai and Indochina Microcontinents or Terranes welded together by the subsequently deformed Nan Suture.... During the Middle Triassic Shan–Thai sutured nearly simultaneously to Indochina and to South China, the continent–continent collision being a part of the Indosinian Orogeny and Indochina tended to underthrust Shan–Thai."
  4. ^ Hirsch et al. 2006,Abstract; Paleozoic, p. 201
  5. ^ Hirsch et al. 2006,Late Permian – Triassic, p. 201
  6. ^ Hirsch et al. 2006,Cenozoic, p. 201