【摘要】：獅泉河 阿索 嘉黎蛇綠混雜巖帶是青藏高原一條重要的構(gòu)造帶，它與班公湖 怒江縫合帶的演化密切相關(guān)，均是青藏高原中部新特提斯洋演化的產(chǎn)物。而拉果錯蛇綠巖是獅泉河 阿索 嘉黎蛇綠混雜巖帶中出露最完整的蛇綠巖組合之一，關(guān)于它的地球化學(xué)研究較為薄弱，它的成因及其構(gòu)造環(huán)境不清楚，時代也存在著爭議。 本文選擇了拉果錯蛇綠巖中相伴生產(chǎn)出的斜長花崗巖和堆晶輝長巖作為重點研究對象，，開展了野外勘查及剖面的測制，對蛇綠巖進行了巖石學(xué)，地球化學(xué)、鋯石LA-ICP-MS U-Pb定年及Lu-Hf同位素的研究，結(jié)合區(qū)域地層和巖漿巖等相關(guān)資料，探討拉果錯蛇綠巖的構(gòu)造屬性。 拉果錯斜長花崗巖和輝長巖野外呈整合接觸產(chǎn)出，地球化學(xué)表明二者具有同源性，具有與E-MORB相似的稀土配分形式和微量特征；Lu-Hf同位素顯示巖漿源區(qū)為虧損地幔，由多種組分組成，可能來源于DDM和EM2二組分混合的地幔源區(qū)；斜長花崗巖和輝長巖的鋯石LA-ICP-MS U-Pb定年分別獲得了184.1±0.79Ma和183.5±2.2Ma的諧和年齡，代表了蛇綠巖的消減時代。研究表明獅泉河 阿索 嘉黎蛇綠混雜巖帶屬于班公湖-怒江縫合帶的一個組成部分，拉果錯蛇綠巖形成于洋內(nèi)弧后盆地環(huán)境。
[Abstract]:The Asuo Jiali ophiolite melange belt in Shiquanhe River is an important tectonic belt in the Qinghai-Xizang Plateau. It is closely related to the evolution of the Bangong Lake Nu River suture zone and is the product of the evolution of the NeoTethys Ocean in the central part of the Tibetan Plateau. The Lago Luo ophiolite is one of the most complete ophiolite assemblages in the Shiquanhe Asuo Jiali ophiolite melange belt. Its geochemical research is relatively weak, its genesis and tectonic environment are not clear, and the age is controversial. In this paper, the plagioclase granites and heap-grained gabbro produced in the Lago Ophiolite are selected as the main research objects, the field exploration and profile survey are carried out, and the petrology and geochemistry of the ophiolite are carried out. LA-ICP-MS U-Pb dating and Lu-Hf isotopic studies of zircon, combined with regional stratigraphy and magmatic data, are used to study the tectonic properties of the Lago dislocation ophiolite. In the field, Laguocao clinopyrofeldite and gabbro show integrated contact. Geochemistry shows that the two have homology, similar rare earth partition form and trace characteristics as E-MORB. Lu-Hf isotopes show that the magmatic source region is a depleted mantle, which is composed of a variety of components and may originate from the mantle source where DDM and EM2 are mixed. The LA-ICP-MS U-Pb dating of zircon from plagioclase granite and gabbro is 184.1 鹵0.79Ma and 183.5 鹵2.2Ma, respectively, which represents the subduction age of ophiolite. The study shows that the Asuo Jiali ophiolite melange belt in Shiquanhe River belongs to an integral part of the Bangonghu-Nujiang suture zone, and the Laguoco ophiolite formed the inner back-arc basin environment of Yu Yang.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P583

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