哀牢山结合带北段侵入岩地球化学特征及地质意义
发布时间：2018-11-27 11:31
【摘要】：哀牢山结合带呈北西—南东向展布,其先后经历了晚古生代—早中生代的特提斯演化,新生代印度板块—欧亚板块碰撞,为一条重要的构造转换响应带。在研究区哀牢山结合带被三条区域性深大断裂所夹持,由北东向南西分别为红河断裂、哀牢山断裂以及阿墨江断裂,不同时期哀牢山结合带内各断裂的活跃造成不同时期侵入岩的发育。本文以构造-岩浆理论指导,对研究区侵入岩岩石学特征、岩石化学特征进行了系统研究。研究区侵入岩主要分布在哀牢山结合带内及两侧,根据SHRIMP锆石U-Pb测年结果可知,研究区侵入岩主要包括印支期及喜山期侵入,喜山期岩体数量为4个,年龄在33~35Ma之间,印支其2个,年龄在194~234Ma之间。其中阿扎鲁小村岩体经过野外观察及室内薄片鉴定得出其分为两期侵入,第一期侵入体SHRIMP锆石U-Pb测年其年龄属印支期;第二期未采得年龄样,根据野外观察及室内薄片鉴定并与其他喜山期岩体对比认为属喜马拉雅期侵入。研究区侵入岩全部为中-酸性侵入岩类,其中,路旁郎岩体为肉红色黑云母石英二长闪长玢岩、肉红色黑云母石英闪长玢岩、紫灰色黑云母石英二长闪长玢岩等的浅成相的闪长玢岩岩体。旧村岩体为灰白色花岗质糜棱岩、糜棱岩化花岗岩、花岗质初糜岩、花岗质片岩等组成的经动力变质的花岗岩。阿扎鲁小村岩体第一期是糜棱岩化二长花岗岩,第二期岩体为碱长白云母花岗斑岩。阿求和岩体为二长花岗岩、钾长花岗岩组成以二长花岗岩为主的岩体。团田山岩体为黑云母石英正长岩及少量黑云母石英二长岩。研究区喜山期岩体属于哀牢山-红河断裂带新生代富碱侵入岩,喜山期岩体地球化学特征为:样品Si O2平均值为72.28%,属于酸性岩类,根据其地球化学特征分析结果其属于过碱质-过铝质过度系列,为碱性岩类,微量及稀土元素特征为明显富集Ba、K大离子亲石元素(LILE),亏损Ta、Nb、P、Ti等高场强元素(HFSE)。稀土元素轻重稀土分馏,属于轻稀土富集型,Eu具轻微的负异常。印支期岩体地球化学特征是为:样品Si O2含量平均值为62.23%,为中-酸性岩体,为过铝质系列。Na2O大于K2O,岩体为碱性系列。微量元素富集Th、U、Pb等,亏损Ba、Ta、Nb、P、Ti等,总体上表现为高场强元素(HFSE)变化较大,大离子亲石元素贫富变化不明显,稀土元素轻重稀土分馏,属于轻稀土富集型。δEu平均值为0.75,Eu具轻微的负异常,表明部分熔融源区无斜长石残留或岩石形成中未发生斜长石结晶分离。喜山期岩体为铝质A型花岗岩,岩浆可能来自于地壳的硅铝层,起源于较为浅的源区,岩浆上升过程中并未明显受到同化混染及结晶分异作用。构造背景处于造山晚期-造山期后的拉伸环境。印支期岩体为S型花岗岩,岩浆起源于浅部源区,岩浆上升侵位过程中收到少量幔源岩浆的混染,构造背景为同碰撞的晚造山期花岗岩。
[Abstract]:The Ailaoshan binding belt, which has undergone the late Paleozoic to early Mesozoic Tethys evolution, and the Cenozoic Indian plate-Eurasian plate collision, is an important tectonic transition response zone. In the Ailaoshan junction zone of the study area, it is held by three regional deep faults, from the north east to the south west of the red river fault, the Ailaoshan fault and the amojiang fault. The active faults in the Ailaoshan binding zone in different periods resulted in the development of intrusive rocks in different periods. Under the guidance of tectonic-magmatic theory, the petrological and petrochemical characteristics of intrusive rocks in the study area are systematically studied in this paper. The intrusive rocks in the study area are mainly distributed in and on both sides of the Ailaoshan binding zone. According to the SHRIMP zircon U-Pb dating results, the intrusive rocks in the study area mainly include Indosinian and Himalayan intrusions, and the number of Himalayan intrusions is 4, and the age is between 33~35Ma. Indosinian 2 of them, between the age of 194~234Ma. The Azzaru Xiaocun rock mass is divided into two stages by field observation and laboratory sheet identification. The first stage SHRIMP zircon U-Pb dating of the intrusive body belongs to the Indosinian age. In the second stage, it is considered to be Himalayan intrusive according to field observation and laboratory sheet identification and comparison with other Himalayan rock bodies. The intrusive rocks in the study area are all intermediate-acid intrusive rocks. Among them, the Lubenlang intrusive body consists of meat-red biotite quartz diorite porphyrite and meat-red biotite quartz diorite porphyrite. Purple gray biotite quartz diorite porphyrite, etc. The Jiucun granite is composed of grayish-white granitic mylonite mylonitic granite granitic primary mylonite granitic schist and other dynamic metamorphic granite. The first stage of the Xiaocun rock body in Azalu is mylonitic monzogranite, and the second stage is the alkali Muscovite granitic porphyry. The ansuonghe rock body is a monzomorphic granite, and the potassium feldspar granite is composed of two-feldspar granites. TuanTian Shan rock body is biotite quartz syenite and a few biotite quartz monzonite. The Xishan rock mass belongs to the Cenozoic alkali rich intrusive rocks in the Ailaoshan-Honghe fault zone. The geochemical characteristics of the Himalayan rocks are as follows: the average value of sample Si O 2 is 72.28, which belongs to acidic rocks. According to the analysis of its geochemical characteristics, it belongs to the peralkaline-peraluminous transitional series and belongs to alkaline rocks. Trace and rare earth elements are characterized by obvious enrichment of Ba,K large ion lithophile element (LILE), depleted Ta,Nb,P,. Ti isopotential field strength element (HFSE). REE fractionation belongs to LREE enrichment type and Eu has slight negative anomaly. The geochemical characteristics of the Indosinian rock mass are as follows: the average Si O 2 content of the sample is 62.23, the intermediate acid rock mass is peraluminous series, the Na2O is larger than K 2O, and the rock mass is alkaline series. Trace elements are enriched in Th,U,Pb, depleted in Ba,Ta,Nb,P,Ti, and so on. In general, the high field strength element (HFSE) changes greatly, the large ion lithophile element does not change obviously, and the rare earth elements are fractionated by light and light rare earth elements. The 未 Eu average value is 0.75% EU with a slight negative anomaly, indicating that there is no plagioclase residue or no plagioclase crystallization separation in the formation of rocks. The Xishan rock body is aluminous A-type granite. The magma may come from the silica-aluminum layer of the crust and originate from a relatively shallow source area. The magma was not obviously assimilated and mixed and crystallized during the process of magma rise. The tectonic setting is in the late orogenic and post-orogenic extensional environment. The Indosinian rock mass is S-type granite, magma originated from shallow source area, a small amount of mantle magma was mixed in the process of magmatic emplacement, and the tectonic setting was a colliding late orogenic granite.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P588.12
本文编号：2360586
[Abstract]:The Ailaoshan binding belt, which has undergone the late Paleozoic to early Mesozoic Tethys evolution, and the Cenozoic Indian plate-Eurasian plate collision, is an important tectonic transition response zone. In the Ailaoshan junction zone of the study area, it is held by three regional deep faults, from the north east to the south west of the red river fault, the Ailaoshan fault and the amojiang fault. The active faults in the Ailaoshan binding zone in different periods resulted in the development of intrusive rocks in different periods. Under the guidance of tectonic-magmatic theory, the petrological and petrochemical characteristics of intrusive rocks in the study area are systematically studied in this paper. The intrusive rocks in the study area are mainly distributed in and on both sides of the Ailaoshan binding zone. According to the SHRIMP zircon U-Pb dating results, the intrusive rocks in the study area mainly include Indosinian and Himalayan intrusions, and the number of Himalayan intrusions is 4, and the age is between 33~35Ma. Indosinian 2 of them, between the age of 194~234Ma. The Azzaru Xiaocun rock mass is divided into two stages by field observation and laboratory sheet identification. The first stage SHRIMP zircon U-Pb dating of the intrusive body belongs to the Indosinian age. In the second stage, it is considered to be Himalayan intrusive according to field observation and laboratory sheet identification and comparison with other Himalayan rock bodies. The intrusive rocks in the study area are all intermediate-acid intrusive rocks. Among them, the Lubenlang intrusive body consists of meat-red biotite quartz diorite porphyrite and meat-red biotite quartz diorite porphyrite. Purple gray biotite quartz diorite porphyrite, etc. The Jiucun granite is composed of grayish-white granitic mylonite mylonitic granite granitic primary mylonite granitic schist and other dynamic metamorphic granite. The first stage of the Xiaocun rock body in Azalu is mylonitic monzogranite, and the second stage is the alkali Muscovite granitic porphyry. The ansuonghe rock body is a monzomorphic granite, and the potassium feldspar granite is composed of two-feldspar granites. TuanTian Shan rock body is biotite quartz syenite and a few biotite quartz monzonite. The Xishan rock mass belongs to the Cenozoic alkali rich intrusive rocks in the Ailaoshan-Honghe fault zone. The geochemical characteristics of the Himalayan rocks are as follows: the average value of sample Si O 2 is 72.28, which belongs to acidic rocks. According to the analysis of its geochemical characteristics, it belongs to the peralkaline-peraluminous transitional series and belongs to alkaline rocks. Trace and rare earth elements are characterized by obvious enrichment of Ba,K large ion lithophile element (LILE), depleted Ta,Nb,P,. Ti isopotential field strength element (HFSE). REE fractionation belongs to LREE enrichment type and Eu has slight negative anomaly. The geochemical characteristics of the Indosinian rock mass are as follows: the average Si O 2 content of the sample is 62.23, the intermediate acid rock mass is peraluminous series, the Na2O is larger than K 2O, and the rock mass is alkaline series. Trace elements are enriched in Th,U,Pb, depleted in Ba,Ta,Nb,P,Ti, and so on. In general, the high field strength element (HFSE) changes greatly, the large ion lithophile element does not change obviously, and the rare earth elements are fractionated by light and light rare earth elements. The 未 Eu average value is 0.75% EU with a slight negative anomaly, indicating that there is no plagioclase residue or no plagioclase crystallization separation in the formation of rocks. The Xishan rock body is aluminous A-type granite. The magma may come from the silica-aluminum layer of the crust and originate from a relatively shallow source area. The magma was not obviously assimilated and mixed and crystallized during the process of magma rise. The tectonic setting is in the late orogenic and post-orogenic extensional environment. The Indosinian rock mass is S-type granite, magma originated from shallow source area, a small amount of mantle magma was mixed in the process of magmatic emplacement, and the tectonic setting was a colliding late orogenic granite.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P588.12
【参考文献】
相关期刊论文 前1条
1 张旗，周德进，赵大升，彭兴阶，罗万林，，刘祥品;滇西古特提斯造山带的威尔逊旋回：岩浆活动记录和深部过程讨论[J];岩石学报;1996年01期
本文编号：2360586
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