四川盐边地区花岗岩类地球化学特征及其成因研究
发布时间：2018-07-31 19:46
【摘要】：攀枝花地区新元古代岩浆活动活跃,侵入岩岩石类型较多,从超基性岩到酸性岩、碱性岩,分布广泛,北起四川丹巴,南至云南峨山,南北向延伸近千公里范围内,大小岩体达60多个。澄清它们的侵位时代、岩石地球化学特征及花岗岩形成机制等问题对揭示攀西裂谷复杂的构造演化历史及其动力学机制至关重要。因此,开展花岗岩的研究不仅可以揭示地壳源区组成、岩石成因,而且有助于恢复造山过程和构造运动历史。测区位于大地构造位置上位于特提斯斯一喜马拉雅构造域的东段,扬子陆块区西南缘。受到印度洋板块、太平洋板块和欧亚板块的影响,造成了地质构造的复杂性和多样性。根据潘桂堂等以大地构造相系对中国大地构造单元进行划分,测区属上扬子陆块西南边缘部分,西临三江弧盆系,横跨康滇基底断隆带和盐源-丽江陆缘裂谷盆地。自晚太古代以来经历了复杂的地质演化过程,是强烈的构造-岩浆活动区。测区的地质构造在四川乃至中国都独具特色,特别是基底的形成与演化和攀西古裂谷的构造-岩浆-沉积作用。测区内花岗岩类主要有晋宁期—澄江期和华力西期两个时期。晋宁期—澄江期主要有大渡口石英闪长岩体、大陆乡石英闪长岩体、水陆乡石英闪长岩体、大尖山石英闪长岩体、关刀山石英闪长岩体,张门扎斜长花岗岩体,以及溼鱼石英正长斑岩体。华力西期主要有二滩、三台坡石英霞石正长岩体。攀枝花盐边地区花岗岩类岩石丰富,本文选取了该区具有代表性的几个花岗岩类运用岩石学、主微量元素、Sr-Nd同位素、锆石U-Pb年代学等方法进行研究,同时对岩体岩石成因及形成的构造背景作出分析,主要取得了以下认识:(1)从主量元素地球化学特征可以看出,研究区花岗岩类型大致可以分为石英闪长岩、斜长花岗岩及石英正长岩三类。三类岩石均表现为铝过饱和特征。石英闪长岩和斜长花岗岩为亚碱性岩石系列,具有钙碱性特征。石英正长岩为碱性岩石系列。其中石英闪长岩的分异指数平均为48.4,分异程度低,斜长花岗岩和石英正长岩的分异指数平均为92.83和85.16,分异程度较高。(2)石英闪长岩中关刀山岩体表现为明显的正Eu异常,稀土元素配分曲线表现为右倾。其余水陆乡、大渡口、大陆乡、大尖山岩体稀土元素配分曲线均表现为向右倾的LREE富集模式,较平滑,δEu、δCe值基本相近,大部分具有不明显或弱负异常特征,表现为同源性。石英闪长岩中,大陆乡、大渡口、水陆乡、大尖山等岩体稀土微量元素总体表现一致,表现出同源性。石英闪长岩中岩石富集大离子亲石元素Rb、Ba、Sr、K等,亏损高场强元素Nb、Ta、P,不相容元素Hf除关刀山其它岩体强烈富集。(3)从本次LA-ICP-MS测试的锆石U-Pb测年结果以及收集到的年龄值,可以看出大致分为937.5Ma,864.3~756.4 Ma,211 Ma这三组。岩体表现为石英闪长岩—斜长花岗岩(二长花岗岩)—石英正长岩演化序列,亚碱性系列—碱性系列的演化顺序。与岩浆岩中性—酸性—碱性演化序列一致。工作区最老的岩体为溼鱼石英正长岩体,年龄937.5Ma。是本次工作的重要发现之一,前人未在攀枝花地区发现过碱性岩。根据岩浆岩演化序列,笔者认为是格林威尔期岩浆演化的延续。其成因为陆内裂谷环境下,由于造山期碰撞作用,使青白口系荒田组的玄武岩发生部分熔融而形成的。晋宁—澄江期864.3~756.4Ma的岩浆活动发育。该期分为三类岩浆,具有I型和S型双重特征的关刀山岩体,S型的水陆乡、大渡口、大陆乡、大尖山岩体。关刀山岩体的形成是由于同构造期下部的地幔物质上涌,古老地壳形成穹窿,由于古老地壳比较薄,在底辟作用下,地幔物质刺穿盖层侵入,形成一种环状整合式的岩体。其是幔源和壳源物质共同作用下形成;水陆乡、大渡口、大陆乡、大尖山岩体则是晋宁—澄江造山运动中,洋壳俯冲碰撞过程中产生的热能使得深部地壳壳源物质发生部分熔融而形成的花岗质岩浆,并且沿裂隙切层贯入。A型的张门扎斜长花岗岩,其形成时代为766.7Ma,较其它岩体时代新。根据该岩体的Nb-Y和Rb-Y+Nb图解,R1-R2图解得知,张门扎斜长花岗岩为岛弧—造山期后构造环境。在前期岩体侵位形成后,造山后期在拉张环境下,使得深部幔源物质沿通道上涌侵位,在侵位过程中可能使得部分壳源物质熔融侵入。二滩、三台坡石英霞石正长岩体最年轻,为211Ma,在Pearce等的Nb-Y和Rb-Y+Nb图解中,两个样品投影在WPG(板内型花岗岩)内及其边缘。在华力西期造山晚期,由于陆内裂谷的拉张,峨眉山玄武岩上涌过程中由于减压发生结晶分异,而形成的高钾钙碱性岩石系列。
[Abstract]:The Neoproterozoic magmatic activities in Panzhihua area are active, and the intrusive rocks have many types of rocks, from ultrabasic rocks to acid rocks and alkaline rocks, widely distributed, north of Sichuan Danba, South to mount EME in Yunnan, and in the extension of nearly 1000 kilometers north and south to more than 60. The emplacement age, rock geochemical characteristics and granitic formation machine are clarified. It is very important to reveal the complex tectonic evolution history and the dynamic mechanism of the Panzhihua rift. Therefore, the study of granite can not only reveal the composition of the source area of the crust, the genesis of the rock, but also help to restore the orogenic process and the history of tectonic movement. The eastern segment of the region, the southwestern margin of the Yangtze block, is affected by the India Ocean plate, the Pacific plate and the Eurasian plate, resulting in the complexity and diversity of the geological structure. According to Pan Guitang and other geotectonic elements, the tectonic units of China are divided into the southwest margin of the Yangtze block, and the Sanjiang arc basin system is on the West. The Kang Dian basement fault belt and the Yanyuan Lijiang continental margin rift basin have undergone complicated geological evolution since the late Archean, and they are strong tectonic magmatic areas. The geological structures of the measured areas have unique characteristics in Sichuan and China, especially the formation and evolution of the basement and the tectonic magmatism and deposition of the Panxi paleo rift. There are two main periods of granitoids: Jinning period Chengjiang period and varisi period. Jinning period and Chengjiang period mainly include Dadukou quartz diorite, Continental quartz diorite, water land quartz diorite, big Jianshan quartz diorite, Guan Dao Shan quartz diorite, Zaga plagioclase granite, and wet fish quartz long Ban Yan There are mainly two beaches and three Poe quartz nepheline syenitals. The granitoid rocks in Panzhihua Yanbian area are abundant. This paper selected several representative granitoids in this area by petrology, main trace elements, Sr-Nd isotopes, zircon U-Pb chronology and so on. At the same time, the petrogenesis and formation of rock rocks were formed. The following understanding is made: (1) from the geochemical characteristics of the principal elements, it is found that the granite types in the study area can be roughly divided into quartz diorite, plagioclase and quartz syenite, and the three types of rocks are characterized by aluminum supersaturation. The rock diorite and the plagioclase are subalkaline rocks. The quartz diorite is a basic rock series. The quartzite diorite is an alkaline rock series, in which the average differentiation index of the quartz diorite is 48.4, the differentiation degree is low, the average differentiation index of the plagioclase and quartz syenite is 92.83 and 85.16, and the differentiation degree is high. (2) the Guan Dao Shan rock in the quartz diorite shows a obvious positive Eu anomaly and the REE distribution. The curve shows right leaning. The distribution curves of the rare earth elements in the rest of the water and land, the Dadu Kou, the mainland and the great Jianshan rock mass are all shown to be the right inclined LREE enrichment model, which is relatively smooth, the delta Eu and delta Ce are almost similar, most of which have the characteristics of unobvious or weak negative anomalies and are homologous, in the quartz diorite, the mainland Township, Dadu, Dadu, Lu townships, big Jianshan and so on The rare earth trace elements in the rock mass have the same overall performance, showing homology. The rocks in the quartz diorite are enriched with large ion stone elements Rb, Ba, Sr, K and so on. The high field and strong element Nb, Ta, P, and the incompatible elements Hf except the other rocks are strongly enriched. (3) the zircon U-Pb dating results from this LA-ICP-MS test and the age values collected can be seen. It is roughly divided into three groups: 937.5Ma, 864.3~756.4 Ma and 211 Ma. The rock mass shows the evolution sequence of quartz diorite - plagioclase (two granitic) - quartz syenite, subalkaline series - alkaline series evolution sequence and the neutral to acidic alkaline evolution sequence of magmatic rocks. The oldest rock mass in the working area is wet fish quartz syenite The age 937.5Ma. is one of the most important discoveries in this work. The predecessors have not found alkaline rocks in the Panzhihua area. According to the magmatic evolution sequence, the author believed that the magma evolution of the Green weir period was a continuation of the magma evolution. The magmatism of the Jinning Chengjiang period 864.3~756.4Ma is developed. This period is divided into three types of magma, which is divided into three types of magma, which have the dual characteristics of I and S type, the S type of water land, Dadu, the mainland and the great Jianshan rock. The old crust is thinner. Under the diapir, the mantle material penetrated the caprock and formed an annular integral rock mass. It was formed under the joint action of the mantle source and the crust source; the water and land, the Dadu, the mainland and the great Jianshan rock mass were in the Jinning Chengjiang orogenic movement. The heat energy produced by the subduction and collision of the oceanic crust made the deep crust. The granitic magma formed by partial melting of the source material and penetrating into the.A type Zhang Menzha plagioclase along the fissure layer is 766.7Ma and is new to the other rock age. According to the Nb-Y and Rb-Y+Nb diagrams of the rock mass, the R1-R2 diagram shows that the Chang gate ligation of the plagioclase is a post orogenic tectonic environment. After the formation of body emplacement, the late orogeny in the extensional environment makes the deep mantle derived material influx along the channel. During the emplacement, some of the shell source materials may be fused into the two shoals, and the three slope quartz nepheline syenite is the youngest, 211Ma. In the Nb-Y and Rb-Y+ Nb diagrams of Pearce and so on, two samples are projected in the WPG (intrarenal granite) In the late stage of the valisi orogeny, the high potassium calc alkaline rock series formed in the upwelling of the Mount Emei basalt during the upwelling of the intracontinental rift and the crystallization differentiation of the basalts during the upwelling of the continental rift.
【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】：P588.121
本文编号：2156644
[Abstract]:The Neoproterozoic magmatic activities in Panzhihua area are active, and the intrusive rocks have many types of rocks, from ultrabasic rocks to acid rocks and alkaline rocks, widely distributed, north of Sichuan Danba, South to mount EME in Yunnan, and in the extension of nearly 1000 kilometers north and south to more than 60. The emplacement age, rock geochemical characteristics and granitic formation machine are clarified. It is very important to reveal the complex tectonic evolution history and the dynamic mechanism of the Panzhihua rift. Therefore, the study of granite can not only reveal the composition of the source area of the crust, the genesis of the rock, but also help to restore the orogenic process and the history of tectonic movement. The eastern segment of the region, the southwestern margin of the Yangtze block, is affected by the India Ocean plate, the Pacific plate and the Eurasian plate, resulting in the complexity and diversity of the geological structure. According to Pan Guitang and other geotectonic elements, the tectonic units of China are divided into the southwest margin of the Yangtze block, and the Sanjiang arc basin system is on the West. The Kang Dian basement fault belt and the Yanyuan Lijiang continental margin rift basin have undergone complicated geological evolution since the late Archean, and they are strong tectonic magmatic areas. The geological structures of the measured areas have unique characteristics in Sichuan and China, especially the formation and evolution of the basement and the tectonic magmatism and deposition of the Panxi paleo rift. There are two main periods of granitoids: Jinning period Chengjiang period and varisi period. Jinning period and Chengjiang period mainly include Dadukou quartz diorite, Continental quartz diorite, water land quartz diorite, big Jianshan quartz diorite, Guan Dao Shan quartz diorite, Zaga plagioclase granite, and wet fish quartz long Ban Yan There are mainly two beaches and three Poe quartz nepheline syenitals. The granitoid rocks in Panzhihua Yanbian area are abundant. This paper selected several representative granitoids in this area by petrology, main trace elements, Sr-Nd isotopes, zircon U-Pb chronology and so on. At the same time, the petrogenesis and formation of rock rocks were formed. The following understanding is made: (1) from the geochemical characteristics of the principal elements, it is found that the granite types in the study area can be roughly divided into quartz diorite, plagioclase and quartz syenite, and the three types of rocks are characterized by aluminum supersaturation. The rock diorite and the plagioclase are subalkaline rocks. The quartz diorite is a basic rock series. The quartzite diorite is an alkaline rock series, in which the average differentiation index of the quartz diorite is 48.4, the differentiation degree is low, the average differentiation index of the plagioclase and quartz syenite is 92.83 and 85.16, and the differentiation degree is high. (2) the Guan Dao Shan rock in the quartz diorite shows a obvious positive Eu anomaly and the REE distribution. The curve shows right leaning. The distribution curves of the rare earth elements in the rest of the water and land, the Dadu Kou, the mainland and the great Jianshan rock mass are all shown to be the right inclined LREE enrichment model, which is relatively smooth, the delta Eu and delta Ce are almost similar, most of which have the characteristics of unobvious or weak negative anomalies and are homologous, in the quartz diorite, the mainland Township, Dadu, Dadu, Lu townships, big Jianshan and so on The rare earth trace elements in the rock mass have the same overall performance, showing homology. The rocks in the quartz diorite are enriched with large ion stone elements Rb, Ba, Sr, K and so on. The high field and strong element Nb, Ta, P, and the incompatible elements Hf except the other rocks are strongly enriched. (3) the zircon U-Pb dating results from this LA-ICP-MS test and the age values collected can be seen. It is roughly divided into three groups: 937.5Ma, 864.3~756.4 Ma and 211 Ma. The rock mass shows the evolution sequence of quartz diorite - plagioclase (two granitic) - quartz syenite, subalkaline series - alkaline series evolution sequence and the neutral to acidic alkaline evolution sequence of magmatic rocks. The oldest rock mass in the working area is wet fish quartz syenite The age 937.5Ma. is one of the most important discoveries in this work. The predecessors have not found alkaline rocks in the Panzhihua area. According to the magmatic evolution sequence, the author believed that the magma evolution of the Green weir period was a continuation of the magma evolution. The magmatism of the Jinning Chengjiang period 864.3~756.4Ma is developed. This period is divided into three types of magma, which is divided into three types of magma, which have the dual characteristics of I and S type, the S type of water land, Dadu, the mainland and the great Jianshan rock. The old crust is thinner. Under the diapir, the mantle material penetrated the caprock and formed an annular integral rock mass. It was formed under the joint action of the mantle source and the crust source; the water and land, the Dadu, the mainland and the great Jianshan rock mass were in the Jinning Chengjiang orogenic movement. The heat energy produced by the subduction and collision of the oceanic crust made the deep crust. The granitic magma formed by partial melting of the source material and penetrating into the.A type Zhang Menzha plagioclase along the fissure layer is 766.7Ma and is new to the other rock age. According to the Nb-Y and Rb-Y+Nb diagrams of the rock mass, the R1-R2 diagram shows that the Chang gate ligation of the plagioclase is a post orogenic tectonic environment. After the formation of body emplacement, the late orogeny in the extensional environment makes the deep mantle derived material influx along the channel. During the emplacement, some of the shell source materials may be fused into the two shoals, and the three slope quartz nepheline syenite is the youngest, 211Ma. In the Nb-Y and Rb-Y+ Nb diagrams of Pearce and so on, two samples are projected in the WPG (intrarenal granite) In the late stage of the valisi orogeny, the high potassium calc alkaline rock series formed in the upwelling of the Mount Emei basalt during the upwelling of the intracontinental rift and the crystallization differentiation of the basalts during the upwelling of the continental rift.
【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】：P588.121
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