四川鹽邊地區(qū)花崗巖類地球化學特征及其成因研究
發(fā)布時間：2018-07-31 19:46
【摘要】：攀枝花地區(qū)新元古代巖漿活動活躍,侵入巖巖石類型較多,從超基性巖到酸性巖、堿性巖,分布廣泛,北起四川丹巴,南至云南峨山,南北向延伸近千公里范圍內(nèi),大小巖體達60多個。澄清它們的侵位時代、巖石地球化學特征及花崗巖形成機制等問題對揭示攀西裂谷復雜的構造演化歷史及其動力學機制至關重要。因此,開展花崗巖的研究不僅可以揭示地殼源區(qū)組成、巖石成因,而且有助于恢復造山過程和構造運動歷史。測區(qū)位于大地構造位置上位于特提斯斯一喜馬拉雅構造域的東段,揚子陸塊區(qū)西南緣。受到印度洋板塊、太平洋板塊和歐亞板塊的影響,造成了地質(zhì)構造的復雜性和多樣性。根據(jù)潘桂堂等以大地構造相系對中國大地構造單元進行劃分,測區(qū)屬上揚子陸塊西南邊緣部分,西臨三江弧盆系,橫跨康滇基底斷隆帶和鹽源-麗江陸緣裂谷盆地。自晚太古代以來經(jīng)歷了復雜的地質(zhì)演化過程,是強烈的構造-巖漿活動區(qū)。測區(qū)的地質(zhì)構造在四川乃至中國都獨具特色,特別是基底的形成與演化和攀西古裂谷的構造-巖漿-沉積作用。測區(qū)內(nèi)花崗巖類主要有晉寧期—澄江期和華力西期兩個時期。晉寧期—澄江期主要有大渡口石英閃長巖體、大陸鄉(xiāng)石英閃長巖體、水陸鄉(xiāng)石英閃長巖體、大尖山石英閃長巖體、關刀山石英閃長巖體,張門扎斜長花崗巖體,以及溼魚石英正長斑巖體。華力西期主要有二灘、三臺坡石英霞石正長巖體。攀枝花鹽邊地區(qū)花崗巖類巖石豐富,本文選取了該區(qū)具有代表性的幾個花崗巖類運用巖石學、主微量元素、Sr-Nd同位素、鋯石U-Pb年代學等方法進行研究,同時對巖體巖石成因及形成的構造背景作出分析,主要取得了以下認識:(1)從主量元素地球化學特征可以看出,研究區(qū)花崗巖類型大致可以分為石英閃長巖、斜長花崗巖及石英正長巖三類。三類巖石均表現(xiàn)為鋁過飽和特征。石英閃長巖和斜長花崗巖為亞堿性巖石系列,具有鈣堿性特征。石英正長巖為堿性巖石系列。其中石英閃長巖的分異指數(shù)平均為48.4,分異程度低,斜長花崗巖和石英正長巖的分異指數(shù)平均為92.83和85.16,分異程度較高。(2)石英閃長巖中關刀山巖體表現(xiàn)為明顯的正Eu異常,稀土元素配分曲線表現(xiàn)為右傾。其余水陸鄉(xiāng)、大渡口、大陸鄉(xiāng)、大尖山巖體稀土元素配分曲線均表現(xiàn)為向右傾的LREE富集模式,較平滑,δEu、δCe值基本相近,大部分具有不明顯或弱負異常特征,表現(xiàn)為同源性。石英閃長巖中,大陸鄉(xiāng)、大渡口、水陸鄉(xiāng)、大尖山等巖體稀土微量元素總體表現(xiàn)一致,表現(xiàn)出同源性。石英閃長巖中巖石富集大離子親石元素Rb、Ba、Sr、K等,虧損高場強元素Nb、Ta、P,不相容元素Hf除關刀山其它巖體強烈富集。(3)從本次LA-ICP-MS測試的鋯石U-Pb測年結果以及收集到的年齡值,可以看出大致分為937.5Ma,864.3~756.4 Ma,211 Ma這三組。巖體表現(xiàn)為石英閃長巖—斜長花崗巖(二長花崗巖)—石英正長巖演化序列,亞堿性系列—堿性系列的演化順序。與巖漿巖中性—酸性—堿性演化序列一致。工作區(qū)最老的巖體為溼魚石英正長巖體,年齡937.5Ma。是本次工作的重要發(fā)現(xiàn)之一,前人未在攀枝花地區(qū)發(fā)現(xiàn)過堿性巖。根據(jù)巖漿巖演化序列,筆者認為是格林威爾期巖漿演化的延續(xù)。其成因為陸內(nèi)裂谷環(huán)境下,由于造山期碰撞作用,使青白口系荒田組的玄武巖發(fā)生部分熔融而形成的。晉寧—澄江期864.3~756.4Ma的巖漿活動發(fā)育。該期分為三類巖漿,具有I型和S型雙重特征的關刀山巖體,S型的水陸鄉(xiāng)、大渡口、大陸鄉(xiāng)、大尖山巖體。關刀山巖體的形成是由于同構造期下部的地幔物質(zhì)上涌,古老地殼形成穹窿,由于古老地殼比較薄,在底辟作用下,地幔物質(zhì)刺穿蓋層侵入,形成一種環(huán)狀整合式的巖體。其是幔源和殼源物質(zhì)共同作用下形成;水陸鄉(xiāng)、大渡口、大陸鄉(xiāng)、大尖山巖體則是晉寧—澄江造山運動中,洋殼俯沖碰撞過程中產(chǎn)生的熱能使得深部地殼殼源物質(zhì)發(fā)生部分熔融而形成的花崗質(zhì)巖漿,并且沿裂隙切層貫入。A型的張門扎斜長花崗巖,其形成時代為766.7Ma,較其它巖體時代新。根據(jù)該巖體的Nb-Y和Rb-Y+Nb圖解,R1-R2圖解得知,張門扎斜長花崗巖為島弧—造山期后構造環(huán)境。在前期巖體侵位形成后,造山后期在拉張環(huán)境下,使得深部幔源物質(zhì)沿通道上涌侵位,在侵位過程中可能使得部分殼源物質(zhì)熔融侵入。二灘、三臺坡石英霞石正長巖體最年輕,為211Ma,在Pearce等的Nb-Y和Rb-Y+Nb圖解中,兩個樣品投影在WPG(板內(nèi)型花崗巖)內(nèi)及其邊緣。在華力西期造山晚期,由于陸內(nèi)裂谷的拉張,峨眉山玄武巖上涌過程中由于減壓發(fā)生結晶分異,而形成的高鉀鈣堿性巖石系列。
[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.
【學位授予單位】：成都理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P588.121
本文編號：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.
【學位授予單位】：成都理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P588.121
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