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首页> 外文学位 >Ductile shear zones and tectonic evolution of northern Qinghai - Tibet Plateau: The Qilian - Qaidam area as an example.
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Ductile shear zones and tectonic evolution of northern Qinghai - Tibet Plateau: The Qilian - Qaidam area as an example.

机译：青藏高原北部延展性剪切带与构造演化-以祁连-柴达木地区为例。

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摘要

The Qilian Mountains and Qaidam Basin occupy the northeastern quarter of the Qinghai - Tibet Plateau. The tectonic evolution can be broadly divided into 4 stages.; Stage 1 (>1,000 Ma) records the earliest history of the area, which was part of a mobile belt surrounding the Tarim Protoplatform.; Stage 2 (1,000–700 Ma) is characterized by Grenvillian-aged orogens and ∼700 Ma tillites, supporting a hypothetical model that the Tarim - Qilian (TaQi), Qaidam and Yangtze Blocks fit into the gap among East Antarctica, Australia and India in the Rodinia Supercontinent. The North China Craton was a stand-alone plate.; Stage 3 (700–250 Ma), which is the focus of this research, is associated with the formation of the Caledonian Qilian Mountains and the united plates of China (UPC). The Qilian were formed through 3 episodes of orogeny: Tulaian (∼495 Ma), Gulangian (∼460 Ma) and Qilianian (∼410 Ma) and the UPC through collisions between TaQi and Qaidam, North China and Yangtze at ∼490 Ma and TaQi and North China at ∼460 Ma.; Stage 4 (Indosinian - Himalayan) relates to re-uplift of the Qilian Mountains and the formation of the northern part of the plateau.; The Tulaian Orogeny resulted from arc accretion and closure of the North Qilian Sea back-arc basin. The basin opened by rift propagating along (Hongliugou ⇒ Lapei Springs?) ⇒ Tulai ⇒ Qilian while the North Qilian Ocean Plate (earliest Tethys?) was subducting southwards under TaQi. The paleo-geography during this period of time was analogous to that of the present-day western Pacific (between 50°N and 20°N). The Gulangian Orogeny involved the closure of the North Qilian Ocean and collision between TaQi - Qaidam and North China - Yangtze. The rates of the convergence and rift propagation were estimated at 1.57–0.7 cm/yr and 1.97–0.45 cm/yr, respectively. The Qilianian Orogeny refers to the intracontinental uplift of the Qilian Mountains during the Caledonian time.; There are three generations of shear zones. The Caledonian and Hercynian shear zones show, respectively, transpressional and transtensional senses of movement, indicating that the plates collided obliquely and then collapsed at a later stage. The Indosinian shear zones, which are all transpressional, are related to Stage 4 tectonism. The ductile shear zone in the Baiying Mining District shows a slight amount of mass volume gain (1.4% ∼ 3.99%) and hardly any bulk volume change. Paleo-temperature estimated for the first three generations of deformation are as follows: D1: 400°C ∼ 370°C, D2: ≈ 340°C and D3: 300°C ∼ 290°C. Paleo-pressure/differential stress ranged between 81.5 ± 9.6 and 100.7 ± 9.6 MPa. The P-T-t-d paths are clockwise.
机译：祁连山和柴达木盆地位于青藏高原的东北部。构造演化大致可分为四个阶段。第一阶段（> 1,000 Ma）记录了该地区的最早历史，该地区是塔里木原型平台周围移动带的一部分。第二阶段（1,000–700 Ma）的特征是格里维利纪年龄的造山带和大约700 Ma的黑岩，支持一种假设模型，即塔里木-祁连（TaQi），柴达木和扬子地块适合于南极东部，澳大利亚和印度之间的缝隙。罗迪尼亚超大陆。华北克拉通是一个独立的板块。第三阶段（700-250 Ma）是本研究的重点，与古苏格兰祁连山和中国联合板块（UPC）的形成有关。祁连系是由三段造山运动形成的：塔拉阶与柴达木，华北与扬子在490阶与塔奇之间的碰撞，由图莱期（〜495 Ma），鼓浪阶（〜460 Ma）和祁连年（〜410 Ma）和UPC形成。华北地区约为460 Ma。第四阶段（印支期－喜马拉雅期）涉及祁连山的隆升和高原北部的形成。图拉山造山运动是由于北祁连海弧后盆地的弧吸积和封闭所致。盆地由裂谷沿（红柳沟⇒拉培温泉？）⇒图莱⇒祁连传播，而北祁连海床板块（最早的特提斯？）则在塔奇的俯冲作用下向南俯冲。在这段时间内的古地理与当今的西太平洋（在50°N至20°N之间）相似。鼓浪山脉的造山运动涉及北祁连海的封闭以及塔旗-柴达木与华北地区-长江之间的碰撞。收敛和裂谷传播的速度分别估计为1.57-0.7 cm / yr和1.97-0.45 cm / yr。祁连年造山带是指喀里多尼亚时期祁连山的陆内隆升。剪切带分为三代。加里东剪切带和海西剪切带分别显示了超压和超张运动感，表明板块倾斜碰撞，然后在后期塌陷。都属于压压性的印支期剪切带与第四阶段构造有关。白营矿区的韧性剪切带仅表现出少量的体积增加（1.4％〜3.99％），几乎没有任何体积变化。前三代变形的古温度估计值如下：D1：400℃〜370℃，D2：＆ap; 340℃和D3：300℃〜290℃。古压力/微分应力在81.5±9.6和100.7±9.6 MPa之间。 P-T-t-d路径为顺时针方向。

著录项

  • 作者

    Ren, Aijun.;

  • 作者单位

    The George Washington University.;

  • 授予单位 The George Washington University.;
  • 学科 Geology.
  • 学位 Ph.D.
  • 年度 2002
  • 页码 298 p.
  • 总页数 298
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 地质学;
  • 关键词

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