湘东北构造活化期花岗岩形成构造环境及成因 |
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引用本文: | 贾大成,胡瑞忠.湘东北构造活化期花岗岩形成构造环境及成因[J].大地构造与成矿学,2001,25(3):277-281. |
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作者姓名: | 贾大成 胡瑞忠 |
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作者单位: | 1. 中国科学院地球化学研究所;吉林大学地球探测与信息技术学院 2. 中国科学院地球化学研究所 |
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基金项目: | 国家自然科学基金,中国科学院知识创新工程项目,中国科学院重点实验室基金,49925309,KZCX2-102,2000,,, |
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摘 要: | 华南大陆从印支期进入陆内活化阶段,形成一系列沿断裂分布的印支期花岗岩。该期花岗岩代表陆内活化期的开始,在岩石地球化学和形成构造环境上以及岩石的形成方式上都与该期以后的花岗质岩石存在一定的差异。表明华南中生代陆内活化构造环境的复杂性和多阶段性。本文以湘东北印支期花岗质侵入岩为例,分析其成岩构造环境,用以反映该区陆内开始活化时的构造环境和活化方式。湘东北印支期花岗质岩石以花岗闪长岩-二长花岗岩岩石系列为主,以相对较低的SiO2、K2O和较高的TiO2、P2O5及负铕异常不明显区别于中生代其它侵入期次岩石,具有陆壳重熔型花岗岩特征,其形成为陆内俯冲导致陆壳物质在俯冲前缘重熔的结果,表明陆内俯冲作用是导致湘东北陆内开始活化的主要方式之一,其构造环境以逆冲式推覆挤压为主。
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关 键 词: | 陆内活化方式 构造环境 印支期 花岗质侵入岩 |
文章编号: | 1001-1552(2001)03-277-05 |
修稿时间: | 2001年5月24日 |
DIAGENESIS TECTONIC SETTING AND MOBILIZING FORM OF GRANITIC ROCKS IN TECTONIC MOBILIZED EPOCH IN NORTHEASTERN HUNAN PROVINCE |
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Abstract: | Continental mobilization began in I ndo-Chinese epoch within South Chin a block,which formed Indo-Chinese epoch gra nitic rocks along deep faults.There are some differences between Indo-Chinese epoch graniti c rocks and other Mesozoic granitic r ocks in lithogeochem-istry and diagenesis tectonic setti ng,which express the nature of multi periodic activity about intracontinental mobilization in n ortheastern Hunan Province.In this paper,the diagenesis tectonic setting of Indo-Chinese ep och granitic rocks in northeastern H unan Province and the tectonic mobilizing forms of intracontinental mobilized epoch are disc ussed and interpreted.The Indo-Chinese epoch granitic rocks i n northeastern Hunan Province belon g to a series of gran-odiorite-adamellite and are different from other epoch granites in high TiO 2 ,P 2 O 5 ,low SiO 2 ,K 2 O,K 2 O +Na 2 O and negative Eu anomalies are not ob vious,having the characteristics o f a crust remixed source.The formatio n of Indo-Chinese epoch granitic rocks were the results of crust remelting along the zone of i ntracontinental subduction.The in tracontinental subduc-tion was the main mobilizing form in n ortheastern Hunan Province.The int rusting,nappe and compression were the main diagenesis tectonic setting,which made the continental crust thickening. |
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Keywords: | Intracontinental mobilizing form tectonic setting northeastern Hunan Province gran-itic rocks Indo-Chinese epoch |
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