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| 古特提斯缝合带澜沧江段花岗岩高温高压实验模拟 | |
| 引用本文： | 刘海龄,王子江,施小斌,丘学林,张伯友,阎贫,夏斌.古特提斯缝合带澜沧江段花岗岩高温高压实验模拟[J].热带海洋学报,2004,23(2):10-18. |
| 作者姓名： | 刘海龄 王子江 施小斌 丘学林 张伯友 阎贫 夏斌 |
| 作者单位： | 1. 中国科学院南海陆空海洋研究所,广东,广州,510301;中国科学院广州地球化学研究所,广东,广州,510640 2. 中国科学院地球化学研究所,贵州,贵阳,510640 3. 中国科学院南海海洋研究所,广东,广州,510301 4. 中国科学院广州地球化学研究所,广东,广州,510640 |
| 基金项目： | 中国科学院知识创新工程项目(KZCX2 209、KZCX2 SW 117和KZCX2 102)，国家重点基础研究发展规划项目(G2000046702)，中央级科研院所社会公益研究专项(2001DIA50041)，国家自然科学基金项目(49972069、49873008和40173001)，中国博士后科学基金项目，中国科学院王宽诚博士后工作奖励基金，中国科学院南海海洋研究所与广州地球化学研究所边缘海地质重点实验室基金项目(BYH02A01) |
| 摘 要： | 对古特提斯主体遗迹的云南西部昌宁-孟连构造混杂缝合带、临沧花岗岩基、澜沧江韧性变形变质带进行了岩石高温高压三轴变形实验模拟研究．以期对该构造带形成时期所处的构造物理环境作出判断。实验岩洋取自紧邻澜沧江韧性剪切变形变质带西侧的临沧花岗岩基。实验后样品产生了一系列新生显微构造，对应的地壳深度环境相当于中下地壳(13-18km)。澜沧江韧性变形变质带花岗岩的显微组构以动力重结晶颗粒极为发育为特征，表明其形成时的环境远比实验深度更深。综合考虑临沧花岗岩基现在的厚度(达15km)和花岗岩浆流动的上限深度(8-10km)以及风化剥蚀量．可以认为临沧花岗岩基的形成深度可大于25km，原始岩浆源于下地壳下部．接近莫霍面的顶面。澜沧江韧性变形变质带的形成与临沧岩基向东逆冲相关．它直抵古特提斯俯冲板块下插滑动顶面。研究表明，昌宁-孟连古特提斯曾发生过真正意义上的大规模洋壳俯冲．是一个具有较大规模的古洋盆。 |
| 关 键 词： | 古特提斯 高温高压实验 澜沧江韧性带 临沧花岗岩基 |
| 文章编号： | 1009-5470(2004)02-0010-09 |
| 修稿时间： | 2002年12月28 |
HIGH-TEMPERATURE HIGH-PRESSURE EXPERIMENTAL SIMULATION ON GRANITE IN LANCANGJIANG SECTION OF TETHYAN SUTURE ZONE IN SW CHINA |
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| LIU Hai-ling.HIGH-TEMPERATURE HIGH-PRESSURE EXPERIMENTAL SIMULATION ON GRANITE IN LANCANGJIANG SECTION OF TETHYAN SUTURE ZONE IN SW CHINA[J].Journal of Tropical Oceanography,2004,23(2):10-18. | |
| Authors: | LIU Hai-ling |
| Institution: | LIU Hai-ling~ |
| Abstract: | In order to understand the tectonophysic environment of Changning-Menglian tectonic-melange-suture zone, Lincang granite batholith, and Lancangjiang ductile deformation metamorphic zone, which are considered as the partial relict of subducted Paleo-Tethys main body, three-axe high-temperature high-pressure creep deformation experiments were conducted on the rock samples from the Lincang granite batholith near the west side of the zone. The samples formed many kinds of microstructures such as brittle deformation (crack and cataclastic structures), brittle-ductile deformation (granulitic and kink band structures) and ductile deformation (strong undulatory extinction flattened enlongated orientation, mechanical twins, kink bands, asysmetric mineral fabrics and augen structures) with temperature/pressure changing from low to high, but dynamically-recrystallized grains can rarely be found in these samples. The experimental temperature/pressure condition corresponds to that of the middle-lower crust (13 to 18km deep). Dynamically-recrystallized grains developed well in the natural rock samples of Lancangjiang ductile deformation metamorphic zone, indicating that the formation depth should be deeper than that reflected by this experiment. Synthetically considering the thickness (up to 15km) of Lincang granite batholith, the upper limit (8 to 10 km) for granite magma to flow, and the weathering erosion, it may be inferred that the formation depth of the Lincang granite batholith should be 30km, and the original magma may come from the lower of low crust, near the upper Moho plane. The formation and outcropping of the batholith resulted from the eastward subduction of Paleo-Tethys under Lanping-Simao block. The subduction finally caused the collision-suture between the Baoshan and the Lanping-Simao blocks. During the collision, the Lincang granite batholith was eastwards pressured and thrust and formed the Lancangjiang ductile-shear deformation-metamorphic zone, which can reach the top plane of the subduction zone of Paleo-Tethys. All of these indicate that real oceanic subduction had ever taken place in the Changning-Menglian Paleo-Tethys, a large-scale ocean. |
| Keywords: | Paleo-Tethys high-temperature high-pressure experiment Lancangjiang ductile-shear zone Lincang granite batholith |
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