摘要
在中亚造山带南缘中国新疆地区划分出塔里木—库鲁克塔格、中天山、伊犁、柯坪四个古块体。塔里木—库鲁克塔格和中天山块体具有一致的前南华纪基底、相似的岩石组合与构造-岩浆演化过程,反映彼此间密切的亲缘性。推测库鲁克塔格在深部可能与塔里木相连,属于塔里木克拉通的一部分。研究表明,中天山是从塔里木克拉通裂解出去的块体,位于两者之间的是通过弧后引张作用而形成的古生代南天山洋盆。伊犁块体在新元古代岩石组合、地层序列、构造环境与演化历史等方面与塔里木块体相似;南华纪裂解以来,差异逐渐明显,并逐渐朝中亚地区的巴尔喀什块体方向运移,到志留纪时增生到哈萨克斯坦板块上,成为巴尔喀什山弯构造带的南部成员。柯坪块体在岩石构造组合、岩层时代、构造环境与演化历史等方面和塔里木—库鲁克塔格、伊犁、中天山三个块体均存在较大差异,属于新元古代洋壳块体。地质证据、岩浆岩年代学证据和碎屑锆石U-Pb年龄谱表明,新疆地区的前寒武纪块体记录了地球早期演化过程中丰富的地壳活动与岩浆作用信息,对全球多期构造-岩浆事件响应积极,包括全球古陆核生长事件、哥伦比亚超大陆聚合事件、罗迪尼亚超大陆聚合与裂解事件。柯坪块体保留了冈瓦纳大陆聚合的信息。
Four Precambrian block, i.e., Kuruk Tag-Tafim, Central Tianshan, Yili and Kepin, were recognized in Xinjiang on the southern margin of Central Asian orogenic belt. Studies show that （1） the Central Tiaushan block has a close affinity with Tarim- Kuruk Tag block , as evidenced by similar pre-Nanhua basement, similar rock assemblages and tectono-magmatic evolutionary processes, implying that Kuruk Tag might be connected with Central Tianshan, and that the Kuruk Tag and Central Tianshan blocks were parts of the Tarim craton during Proterozoic period; （2） the Central Tianshan is a sub-block which was split from the northern Tarim craton during Neoproterozoic Nanhua period, and the Paleozoic Southern Tianshan oceanic basin was developed between the two blocks; （3） the Yili block was similar to the Tarim craton before Neoproterozoic Nanhua period in such aspects as rock assemblages, stratigraphic sequences, tectonic settings and evolution, showing some aifrtides for Tafim craton. After Nanhua period, geological differences between two blocks became obvious, and in Paleozoic, the Yili block might be linked with the Balkhash block, and in Silurian, two blocks amalgmated; （4） the Kepin block is an oceanic crustal terrane completely different from Kuruk Tag, Central Tianshan and Yili blocks in terms of rock assemblages, stratigraphic sequences, ages and evolutional history. Evidence from geological, magmatic and geochronological features and distribution of detrital zircon U-Pb ages show that Precambrian blocks （Kuruk Tag- Tarim, Central Tiaushan, Yili and Kepin）of the northern Xinjiang region recorded abundant information of crustal deformation and magmatism during the early evolution of the Earth, suggesting a strong response to the global polyphase tectonic and magmatic events, including growth of the global continental core, assembly of the global Columbia, and assembly and breakup of the global P, odinia supercontinent. In contrast.to the Kuruk Tag-：Tarim, Central Tianshan and Yili blocks, the Kepin block preserved some records of the assembtv event of Gondwana.
出处
《中国地质》
CAS
CSCD
北大核心
2013年第1期43-60,共18页
Geology in China
基金
国家重点基础研究发展规划项目(2007CB411301)
全国优秀博士论文(FANEDD 201130)
教育部博士点基金(20120091110024)
中国学者委员会项目(201206190049)
南京大学内生金属矿床成矿机制研究国家重点实验室研究项目(2008-I-01)资助
关键词
古块体
构造-岩浆作用
聚合与离散
超大陆
中亚造山带
中国新疆
ancient blocks
tectono-magmatism
assembly and breakup
superconfinent
Central Asian orogenic belt
northern Xinjiangregion
