發(fā)布時間：2018-06-18 04:56

  本文選題：雀兒山巖體 + 巖石地球化學特征　； 參考：《成都理工大學》2015年碩士論文

【摘要】：雀兒山花崗巖體位于四川省西北部德格縣境內,緊鄰西藏自治區(qū),總體屬北東高南西低的典型高山深切割區(qū)。雀兒山巖體侵入于德格-鄉(xiāng)城大斷裂與甘孜-理塘深斷裂交匯的三角地帶的二疊系及上三疊統(tǒng)板巖、變砂巖中,被古近系沉積巖不整合覆蓋,巖體以不規(guī)則復雜形態(tài)的巖基產出。雖然前人對雀兒山巖體的區(qū)域地質調查和研究已取得了較多成果,也有相關的專著出版和文章發(fā)表,但通過本次論文對雀兒山巖體的野外地質調查發(fā)現(xiàn),前人研究對于該巖體侵入?yún)^(qū)域的地質、構造及演化歷史,以及區(qū)域主要斷裂的延伸、性質、幾何學與運動學特征及其形成演化過程等的研究,尚缺少足夠的實際資料和數(shù)據(jù)支撐。特別是關于雀兒山巖體與成礦作用的關系問題,尚顯得十分薄弱。有鑒于此,本論文以雀兒山巖體的巖石學、巖石地球化學及其成因研究為選題,試圖通過對巖體深入的野外地質調查、系統(tǒng)的巖石樣品采集、測試和鏡下鑒定,對雀兒山巖體進行解剖研究,力求深入掌握雀兒山巖體巖石類型及其宏觀微觀巖石學特點、侵入期次。特別是通過巖石地球化學特征研究,分析判斷雀兒山巖體侵入的大地構造屬性,進而探討巖體就位機制。通過對雀兒山巖體及鄰區(qū)其他酸性巖體的對比研究,重點了解研究區(qū)與酸性深成巖體有關的礦床(礦點)的礦種、類型、規(guī)模,適當開展礦床學、礦床地球化學研究,尋求礦床與巖體二者的關聯(lián)性,進而歸納巖體成礦專屬性,為區(qū)域上尋找與酸性巖體有關的礦產資源提供基礎數(shù)據(jù)支持。雀兒山巖體大地構造上位于羌塘-三江造山系一級構造單元內甘孜-理塘弧盆系二級構造單元,隸屬于義敦-沙魯里島弧帶三級構造單元。該島弧帶又稱義敦島弧,也有稱昌臺-鄉(xiāng)城島弧帶,以居德來-定曲、木龍-黑惠江斷裂和甘孜-理塘蛇綠混雜巖帶的馬尼干戈-拉波斷裂為其東界,包括義敦-白玉-鄉(xiāng)城-稻城及三江口地區(qū)。義敦-沙魯里島弧是在中咱地塊東部被動陸緣基礎上,于晚三疊世早中期受甘孜-理瑭洋向西俯沖制約形成。義敦-沙魯里島弧帶深成巖漿活動規(guī)模較大,構成非常醒目的帶狀巖漿弧,可以分為東西兩個亞帶。東亞帶侵入巖漿活動的時代為237.5-208.0Ma,侵位形成與晚三疊世島弧火山巖同期異相,巖石類型以中粗粒斑狀二長花崗巖為主,次為花崗閃長巖,少量閃長巖、閃長玢巖、花崗斑巖等,從早到晚巖石為閃長巖→花崗閃長巖→二長花崗巖→花崗巖→花崗斑巖,亦即向酸堿質增高、鉀鈉比增大的方向演化。尤其是東亞帶南段的部分二長閃長玢巖-花崗斑巖小巖體(年齡208-235Ma)控制了斑巖型銅礦床的生成,如普朗特大型斑巖型銅礦、雪雞坪中型斑巖型銅礦等。后碰撞造山期花崗巖年齡為208-138Ma,主要巖石類型為二云母花崗巖和鉀長花崗巖,次為二長花崗巖和二長閃長巖,疊加在俯沖期花崗巖帶之上,主要發(fā)育于島弧帶的北段,是西南三江中段北帶有色和貴金屬成礦區(qū)形成的地質構造條件。雀兒山巖體就是在這樣的構造背景下侵入形成。本論文研究區(qū)地層屬羌塘-三江地層大區(qū)下的巴顏喀拉地層區(qū)的德格-中甸(香格里拉)地層小區(qū)。巖體附近出露地層主要有上三疊統(tǒng)圖姆溝組(T3t)、喇嘛埡組(T3lm)以及第四系沉積物。雀兒山花崗巖體出露巖石類型,主要似斑狀黑云母二長花崗巖、二長花崗巖、似斑狀二長花崗巖、黑云母花崗巖、石英閃長巖等。本文通過對巖石的常量、微量、稀土元素測試發(fā)現(xiàn),巖石SiO2含量普遍在63.29%-79.16%,Al2O3含量變化在10.50%-15.21%之間,根據(jù)SiO2與常量元素氧化物(Al2O3、CaO、Na2O、K2O、TiO2等)關系圖解,閃長巖樣品均落于高鉀鈣堿性系列區(qū)域,其余花崗巖類樣品則落于高鉀鈣堿性系列和鉀玄巖系列區(qū)域。在微量元素方面總體有相似的微量元素原始地幔標準化分布模式,巖石虧損大離子親石元素Ba、Sr,P、Ti,不相容元素Rb、Th、U、K、Hf在巖體中富集。再結合Nb*、K*、Sr*、Zr*比值,推斷雀兒山花崗巖基應屬于島弧帶與碰撞造山有關的構造背景下侵位。稀土元素總體特點,ΣREE介于110.407-409.238之間,平均值為236.956;LREE介于82.798-378.822之間,平均值為211.268;HREE介于13.232-39.831之間,平均值25.688;LREE/HREE介于2.621-18.893之間,平均值為8.505;(La/Yb)N比值均大于1;Eu負異常顯著(普遍δEu1);Ce無明顯異常(δCe≈1),指示雀兒山巖體為堿性較高酸性巖體,應屬于典型地殼重熔“S”型花崗巖。根據(jù)稀土、微量元素蛛網圖、常量元素構造環(huán)境判別圖,也顯示出雀兒山花崗巖基就位機制在火山弧-同碰撞構造環(huán)境中。巖體形成的同位素年齡為102.23±0.91Ma。雀兒山巖體及鄰區(qū)已發(fā)現(xiàn)的礦床主要為熱液型、矽卡巖型以及斑巖型礦床,雀兒山巖體二長花崗巖、鉀長花崗巖為主構成的巖石單元與稀土礦床有關。以鉀長花崗巖或K2ONa2O的堿長花崗巖單元與W、Sn、Mo、Bi、Be礦化有關。以Na2OK2O的堿長花崗巖組成的單元與Nb、Ta礦化有關。以黑云母花崗巖為主構成的單元與稀土、W、Sn礦有關。以二云母花崗巖為主組成的單元與W、Sn、Mu、Bi、Be有關。以白云母花崗巖為主構成的單元與Be、Nb、Li、Ta、Rb等礦化有關。本論文發(fā)現(xiàn)的圍巖蝕變類型包括:鉀長石化→鈉長石化→云英巖化→角巖化。本論文研究認為,雀兒山花崗巖基內及其圍巖接觸帶有尋找上述礦種的矽卡巖、角巖型及云英巖型礦床的可能。
[Abstract]:The Nestle mountain granite body, located in dege County, northwest of Sichuan Province, is close to the Tibet autonomous region and belongs to the typical North East High South West low deep cutting area. The Nestle mountain intrusion is intruded on the Permian and upper three Permian slates in the triangle zone between the DGE Xiangcheng big fault and the Ganzi Litang deep fault, and in the sandstone, the Paleogene sedimentary rocks are changed. Unconformities covered, rock mass produced in irregular and complex forms. Although many achievements have been made in the regional geological investigation and research of the rock mass of the fours mountain, some published publications and articles have been published. The study of geological, tectonic and evolutionary history, and the extension of major faults in the region, properties, geometric and kinematic characteristics and their formation and evolution process are still lacking sufficient actual data and data support. In particular, the relationship between the rock mass and the mineralization of the fill mountain is still very weak. The study of rock petrology, rock geochemistry and genesis of rock mass is selected as a topic. Through an in-depth field geological survey of rock mass, systematic rock sample collection, test and microscopic identification, an anatomical study of the rock mass of the sill mountain is carried out in order to grasp the rock types of the rock mass in the rock mass of the Mt. Through the study of geochemical characteristics of rock and geochemistry, the geodetic properties of the intruding of the rock mass in the sill mountain are analyzed and judged, and then the mechanism of rock mass is discussed. Through the comparison of the rock mass and other acidic rock mass in the adjacent area, the mineral deposits (ore points) related to the acid deep rock mass, the type, the scale, and the proper development of the ore are discussed. The geochemical study of the deposit and the mineral deposit seeks the association between the two elements of the ore deposit and the rock mass, and then generalizes the special properties of the rock mass, and provides the basic data for the mineral resources related to the acid rock mass. The rock mass geodetic is located in the two grade structure of the Ganzi Litang arc basin system in the first tectonic unit of the Qiangtang Sanjiang orogenic system The unit, which belongs to the three level tectonic unit of the Yun - Sha Lu island arc belt, is also known as the Yun island arc, also known as the Changtai - Xiangcheng island arc belt, with the Gudai - Ding Qu, the Mong - Heihui River fault and the mani - ge - La - Po fault in the Ganzi - Litang OPHIOLITIC MELANGE belt to the East, including Yun - Bai Yu - Xiang City Daocheng and Sanjiang mouth areas. The shabumi island arc is based on the passive continental margin of the east of the central Zan massif and was formed by the Ganzi - neo - oceanic subduction in the early and middle period of the late three fold. The Yun - Sha Lu island arc zone has a large scale of deep magmatic activity, forming a very awakening banded magmatic arc and can be divided into two subzones of East and West. The era of intruding magmatic activity in East Asia zone is 237.5-2 08.0Ma, the formation of emplacement and late three superposition of the island arc volcanic rocks in the same period, the rock type is mainly the medium coarse grained two long granite, the second is granodiorite, a small amount of diorite, diorite porphyrite and granite porphyry, and from early to late, the rocks are diorite, granodiorite, two long flower granitic rock, granite and granite porphyry. In particular, the part of the two long diorite porphyry porphyry porphyry porphyry rock mass (age 208-235Ma) in the southern part of the East Asia zone controls the formation of porphyry copper deposits, such as the plutt large porphyry copper deposit and the medium porphyry copper deposit in the snow chicken Ping. The post collision orogenic granites are 208-138Ma and the main rock type is two. The mica granite and the potassium feldspar are two and two long diorite, superimposed on the subduction granite belt, mainly in the northern section of the island arc belt, which are the geological conditions for the formation of the nonferrous and noble metal metallogenic zone in the North Zone of the middle section of the southwest Sanjiang. The area of the study area belongs to the DGE Zhongdian (Shangri-La) stratigraphic plot in the Bayan La stratigraphic area under the Qiangtang Sanjiang stratigraphic area. The outcropping strata near the rock mass are mainly the upper three series of the Tong Mu Gou formation (T3t), the Lama pass group (T3lm) and the Quaternary sediments. Two long granite, porphyritic two feldspar, biotite granite, quartz diorite, etc., in this paper, we found that the content of SiO2 in rock is generally in 63.29%-79.16%, Al2O3 content varies between 10.50%-15.21%, according to the relationship between SiO2 and the constant element oxide (Al2O3, CaO, Na2O, K2O, TiO2, etc.). The samples of the long rock fall in the high potassium calc alkaline series, and the other granitoid samples fall in the high potassium calc alkaline series and the series of potassium basalite series. In the aspect of trace elements, there are similar trace elements of the primitive mantle standard distribution pattern. The rock loss of large ion stone elements Ba, Sr, P, Ti, the incompatible elements Rb, Th, U, K, Hf are rich in the rock mass. Nb*, K*, Sr* and Zr* ratio, it is concluded that the gill mountain granite base should belong to the emplacement under the tectonic setting related to the island arc zone and the collision orogeny. The overall characteristics of the rare earth elements are between 110.407-409.238, the mean value is 236.956, the LREE is between 82.798-378.822, the average value is 211.268, HREE is between 13.232-39.831, and the average value is 25.688. The average value of LREE/HREE is 8.505, the average value is 8.505, the ratio of (La/Yb) N is greater than 1, and the negative anomaly of Eu is significant (general Delta Eu1); Ce has no obvious anomaly (delta Ce 1). It indicates that the Nestle mountain rock is a high alkaline acidic rock mass and should belong to the typical crust remelting "S" granitic rock. It is also shown that the location mechanism of the broth mountain granite base is in the volcanic arc and collision tectonic environment. The isotopic age of the rock mass is 102.23 + 0.91Ma., and the deposits found in the rock and adjacent areas are mainly hydrothermal, skarn and porphyry deposits, sparrow Yamakawa Stani granites and potassium feldspar granite. The unit is related to the rare earth deposit. The K-feldspar or K2ONa2O alkali feldspar unit is related to the mineralization of W, Sn, Mo, Bi, Be. The unit composed of the alkali granite of Na2OK2O is related to Nb and Ta mineralization. The unit composed mainly of the biotite granite is related to the rare earth, W, Sn ore. The unit consisting mainly of two mica granite and W The elements composed mainly of muscovite granite are related to the mineralization of Be, Nb, Li, Ta and Rb. The types of rock alteration found in this paper include: potassium long fossilization, sodium feldspar, cloud angling, and corner rock. The possibility of a rock type deposit.
【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】：P587

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