本文選題：苗兒山—越城嶺 + 界牌　； 參考：《中國科學院研究生院(廣州地球化學研究所)》2016年博士論文

【摘要】：苗兒山—越城嶺復式巖體位于南嶺西段,由多期多階段巖漿活動形成的侵入巖組成,過去多認為復式巖體主體為加里東期花崗巖,印支期花崗巖也分布較為廣泛,且零星出露燕山期小巖株,但缺少精確的同位素定年。在苗兒山—越城嶺復式巖體與圍巖的接觸帶中,形成眾多大大小小的礦床及礦點,圍繞復式巖體形成礦集區(qū),較著名礦床主要有牛塘界W礦床、界牌W-Cu礦床、長崗嶺Pb-Zn多金屬礦床及云頭界W-Mo礦床等。近年來,研究人員對苗兒山—越城嶺復式巖體時空分布、地球化學特征、來源及礦床的形成年齡等方面進行了研究,并獲得了不少成果。但對于區(qū)內礦床形成演化過程、成礦巖體地球化學特征、成礦與非成礦巖體差異等研究工作相對較少。苗兒山—越城嶺礦集區(qū)發(fā)育不同成礦元素組合的礦床,由于缺少典型礦床成巖成礦過程剖析,礦化與賦礦巖體關系不清,因而對形成不同成礦元素組合礦床的主要控制因素了解不多。綜上所述,苗兒山—越城嶺礦集區(qū)仍主要存在以下問題:(1)苗兒山—越城嶺區(qū)域系統(tǒng)的成巖成礦時空分布如何?成礦作用主要發(fā)生于加里東期、印支期還是燕山期?(2)相關礦床成礦巖體有何地球化學特征及其成礦流體的演化過程?(3)形成礦集區(qū)內不同成礦元素組合礦床的主要控制因素是什么?針對上述問題,本次工作以界牌W-Cu、牛塘界W和舜皇山W礦床等為研究對象。開展如下工作:(1)通過野外地質調查及資料的全面收集、礦化蝕變特征及礦化期次等觀察分析,厘清礦化相關的侵入巖的關系,初步厘定相關成礦巖體;(2)測定成礦期白云母Ar-Ar同位素年齡及賦礦巖體和礦區(qū)周邊相關侵入巖的LA-ICP-MS鋯石U-Pb年齡,了解巖體時空結構及確定成巖成礦演化系列;(3)測定礦區(qū)內外的主要類型巖石的主微量元素和Sr-Nd-Hf同位素組成,分析成礦巖體及相關侵入巖的地球化學特征及源區(qū)特征,深入探討不同成礦元素組合礦床成礦巖體源區(qū)差異;(4)分析不同類型礦床成礦流體特征及演化,結合蝕變特征,揭示不同類型成礦元素沉淀析出主要控制因素。本工作主要取得了下列成果:(1)苗兒山—越城嶺一帶與礦化相關巖體主要形成于加里東期及印支期,礦集區(qū)內主要礦床與加里東期和印支期巖漿活動有關,而不是過去認為的燕山期。苗兒山—越城嶺礦集區(qū)界牌、牛塘界、舜皇山等3個礦區(qū)主要賦礦巖體及咸水鄉(xiāng)閃長巖和五星村淺色巖體LA-ICP-MS鋯石U-Pb年齡表明,舜皇山W礦區(qū)的兩期花崗巖侵入年齡分別為219.6±2.4Ma和220.3±3.6Ma;界牌礦區(qū)兩期早期巖基和晚期巖脈的年齡分別為422±11Ma、428.3±6.5Ma和410±7.4Ma;咸水鄉(xiāng)閃長巖的年齡為431.4±3.8Ma;五星村淺色巖體的年齡為412±14Ma;牛塘界礦區(qū)外圍兩期巖基的年齡分別為430±4.9ma和432.2±8.4ma。除舜皇山礦區(qū)的兩期花崗巖形成于印支期外,其余礦區(qū)相關侵入巖的形成時代均為加里東期。界牌w-cu礦產于斑狀黑云母花崗閃長巖和灰?guī)r接觸帶矽卡巖中及從巖體至圍巖顯示從中高溫蝕變礦物組合至中低溫蝕變礦物組合等表明礦化與斑狀黑云母花崗閃長巖有關,礦床形成于加里東期,約為422±11ma;舜皇山w礦主要為脈狀產于印支期花崗巖中,賦礦巖體發(fā)生廣泛的云英巖化,表明w礦與賦礦巖體具有內在成因關系,成礦主要發(fā)生在印支期,約為220ma。前人成果表明,苗兒山—越城嶺礦集區(qū)牛塘界w礦是加里東期形成的,云頭界w-mo礦和高嶺w礦床是印支期形成的。因此,苗兒山—越城嶺礦集區(qū)內的w-mo、w、w-cu等礦床主要形成于加里東期和印支期。(2)苗兒山—越城嶺復式巖體主要為過鋁質花崗巖,具有殼源花崗巖的地球化學特征,主要是中晚元古代基底地殼部分熔融形成的。苗兒山—越城嶺復式巖體主體為酸性巖,發(fā)育有少量中性巖。其主量元素都表現(xiàn)為高si、富k、貧mg的特征,屬鈣堿性-高鉀鈣堿性系列,且全部樣品為過鋁質花崗巖,微量元素明顯富集rb、th、u及虧損sr、ba、ti,稀土元素呈明顯的eu負異常,總體顯示殼源花崗巖的特征。且界牌、牛塘界礦區(qū)晚期淺色巖體都呈現(xiàn)稀土總量偏低,稀土配分模式呈“海鷗狀”等特征,與南嶺其他地區(qū)燕山期w-sn成礦巖體地球化學特征相似。舜皇山鎢礦花崗巖具有低εnd(t)(-9.33~-10.58)值和低εhf(t)(-5.9~-10.5)值,對應的nd、hf二次模式年齡分別為1907~2760ma和1626~1918ma,與牛塘界w、云頭界w-mo礦成礦巖體的同位素特征相似,由古地殼重熔形成;界牌礦區(qū)鎢銅礦化有關巖體的εnd(t)(-5.91~-7.92)值和εhf(t)(-4.4~-10.7)值呈較大負值,nd和hf二次模式年齡分別為1621~1963ma及1690~2088ma,總體具有殼源的特征,但其εnd(t)值相對較高,且其εhf(t)值比較分散,表明其源區(qū)和舜皇山鎢礦化巖體有一定差異,可能含有一些地幔或新生地殼物質。(3)成礦巖體來源是控制區(qū)內礦床形成不同成礦元素組合的重要因素。界牌w-cu礦床和舜皇山w礦床、牛塘界w礦床和云頭界w-mo礦床成礦巖體地球化學化特征有一定的差異,前者相對低硅高鐵鎂鈣及具較高的εnd(t)值,后者高硅,具高演化花崗巖特征及相對更低的εnd(t)值。這表明苗兒山—越城嶺礦集區(qū)高演化花崗巖有利于w和w-mo礦床的形成,而cu-w礦化則和非高演化花崗巖具親緣性。w和w-mo成礦花崗巖主要為古老基底部分熔融形成的,而w-cu礦化花崗巖源區(qū)可能含有少量地幔(新生地殼物質)。巖漿源區(qū)及成巖過程中演化程度差異可能是形成不同成礦元素組合礦床的主要控制因素。(4)界牌矽卡巖型w-cu礦成礦流體主要為中高溫、低鹽度NaCl-H2O-CO_2-CH4熱液體系,流體混合為其成礦元素沉淀的主要機制;舜皇山W礦成礦流體主要為中低溫、低鹽度NaCl-H2O-CO_2-CH4熱液體系,流體冷卻降溫為其成礦元素沉淀的主要因素,流體不混溶也可能是因素之一。我們分析了界牌矽卡巖W-Cu礦床偉晶巖、白鎢礦石和晚期石英脈三個不同成礦階段的流體特征。偉晶巖石英中的流體包裹體均一溫度峰值為310~330°C,鹽度為0.18~5.71%NaCleqv,拉曼光譜顯示氣體中具有CO_2和CH4的成分,屬于中高溫、低鹽度NaCl-H2O-CO_2-CH4熱液體系;白鎢礦石中流體包裹體均一溫度具有兩個峰值,分別為260~280°C和320~340°C,鹽度為0.35%~5.56%NaCleqv,屬中高溫、低鹽度熱液范疇;晚期石英脈均一溫度峰值為270~300°C,鹽度為0.18~3.71%NaCleqv,氣體中亦含有CO_2和CH4的成分,屬中溫、低鹽度范疇。界牌W-Cu礦白鎢礦礦石中的流體均一溫度和鹽度具有明顯正相關的線性關系,說明其經(jīng)歷了流體混合作用,促使成礦元素沉淀。觀察分析了舜皇山礦區(qū)成礦花崗巖、云英巖和晚期石英脈三個階段的流體包裹體特征。巖體階段石英中未見熔融包裹體,測試對象主要為流體包裹體,其均一溫度峰值為210~240°C,鹽度為0.18~3.55%NaCleqv,與云英巖階段流體包裹體均一溫度、鹽度特征相似,推測其受云英巖階段熱液改造形成,同時在云英巖石英包裹體氣體中發(fā)現(xiàn)CO_2和CH4,因此兩個階段同屬中溫、低鹽度NaCl-H2O-CO_2-CH4熱液體系;晚期石英脈均一溫度峰值為190~220°C,鹽度為0.18~3.71%NaCleqv,其氣體成分中也含有CO_2和CH4,屬中低溫、低鹽度NaCl-H2O-CO_2-CH4熱液體系。而舜皇山W礦床主成礦階段云英巖中的流體包裹體溫度跨度較大,但鹽度處于一個較小的范圍,說明其經(jīng)歷了流體冷卻降溫過程,造成成礦元素沉淀,同時見少量富氣相與富液相兩類包裹體共生,且富氣相包裹體均一溫度較高,說明其經(jīng)歷了流體不混溶,這也可能是造成成礦元素沉淀的因素之一。
[Abstract]:The Miao mountain - Yuecheng ridge complex is located in the western section of Nanling, which is composed of intrusive rocks formed by multi stage and multi stage magmatic activities. In the past, the main body of complex rock mass was CALEDONIAN GRANITE, and the Indosinian granites were also widely distributed, and the small rocks were scattered in Yanshan period, but the exact isotope dating was scarce. In the contact zone of complex rock mass and surrounding rock, many large and small ore deposits and ore spots are formed, and the ore deposits are formed around complex rock mass. The famous ore deposits are mainly Niu Tong W deposit, Jie brand W-Cu deposit, Chang Gang Ling Pb-Zn polymetallic deposit and cloud head W-Mo deposit. In recent years, the researchers have made the spatial and temporal distribution of the compound rock mass in Miao mountain - Yuecheng ridge. The geochemical characteristics, sources and the age of the formation of the deposit have been studied, and many achievements have been obtained. However, there are relatively few research work on the formation and evolution process of the deposits in the area, the geochemical characteristics of the ore-forming rock mass and the difference of metallogenic and non metallogenic rocks. Due to the lack of analysis of typical ore forming and metallogenic processes, the relationship between mineralization and ore bearing rock mass is not clear, so the main control factors for the formation of different metallogenic elements are not well understood. In summary, the following problems still exist in the Miao Er mount Yuecheng Ling ore collection area: (1) the spatial and temporal distribution of the diagenesis and mineralization of the Miao Er mountain Yuecheng ridge regional system, for example What is the mineralization mainly occurring in Caledonian, Indosinian or Yanshan period? (2) what are geochemical characteristics and evolution process of ore-forming fluids in the related ore deposits? (3) what are the main controlling factors for the formation of different ore-forming elements in the ore-forming area? For the above problems, this work is based on the W-Cu, Niutang boundary W and shun. The Huangshan W deposit is the research object. (1) through the comprehensive collection of field geological survey and data, the characteristics of mineralized alteration and the secondary observation and analysis of mineralization period, the relation of mineralization related intrusive rocks is clarified, and the Related Ore-forming rock mass is preliminarily identified; (2) the age of the Muscovite isotopes in the Ce Dingcheng period, the ore bearing rock mass and the mining area The LA-ICP-MS zircon U-Pb age of the associated intrusive rocks, to understand the spatial and temporal structure of rock mass and to determine the series of diagenetic and metallogenic evolution; (3) to determine the main trace elements and Sr-Nd-Hf isotopes of the main types of rock in the mining area and to analyze the geochemical and source characteristics of the ore-forming and related intrusive rocks, and to explore the different metallogenic elements in depth. The differences in the source area of the ore-forming rock mass of the ore deposit are found. (4) to analyze the characteristics and evolution of the ore-forming fluids of different types of ore deposits and to reveal the main controlling factors for the precipitation and precipitation of different types of metallogenic elements. The main results are as follows: (1) the mineralization related rocks in the Miao mountain and Yuexing area are mainly formed in Caledonian and Indosinian periods. The main ore deposits in the ore gathering area are related to the Caledonian and Indosinian magmatic activities, but not the Yanshan period in the past. The main ore bearing rocks in the 3 mining areas of the Miao and Yuecheng ridge, the Niu Tang and Shun Huangshan, and the LA-ICP-MS zircalo U-Pb age of the salt water and the Wuxing village light color rock show that the two phases of the granite in the W mining area of Shun Huangshan The age of rock intrusion is 219.6 + 2.4Ma and 220.3 + 3.6Ma, respectively, the age of the early rock base and late vein in the two phases of the Jie brand mining area is 422 + 11Ma, 428.3 + 6.5Ma and 410 + 7.4Ma, the age of the diorite in salty water Township is 431.4 + 3.8Ma, the age of the five star village light color rock mass is 412 + 14Ma, and the age of the two phases of the periphery of the Niu Tang mining area is 430 + 4.9ma, respectively. The two phases of granite, except Shun Huangshan mining area, formed in the Indosinian period, and the formation times of the related intrusive rocks in the other mining areas are all Caledonian. The W-Cu mineral is in the porphyritic mica granodiorite and limestone contact belt skarn, and from the rock mass to the surrounding rock, the mineral assemblage from the middle and high temperature alteration mineral to the medium and low temperature alteration mineral group is shown from the rock mass to the surrounding rock. The mineralization is related to the porphyritic biotite granodiorite. The deposit is formed in Caledonian period, which is about 422 + 11ma, and the w mine of Shun Huangshan is mainly produced in the Indo branch granite, and the ore bearing rock mass has a wide range of cloud and rock formation. It indicates that the w ore and the ore bearing rock have an inherent genetic relationship, and the mineralization occurs mainly in the Indosinian period, which is about 220ma. predecessors. The results show that the w ore of the niintang boundary in the Miao mountain - Yuecheng Ling ore area is formed in Caledonian period, and the W-Mo ore and the kaolin w deposit of the cloud head boundary are formed in the Indosinian period. Therefore, the W-Mo, W and W-Cu deposits in the Miao mountain - Yuecheng Ling ore gathering area are mainly formed in Caledonian and Indo Chinese periods. (2) the Miao and Yuecheng ridge complex rock mass is mainly peraluminous granite. The geochemical characteristics of the rock, with the crust source granite, are mainly formed by partial melting of the basement crust of the middle and late Proterozoic. The main body of the Miao mountain - Yucheng ridge complex body is acid rock and a small amount of neutral rocks. Its main elements are characterized by high Si, K rich and poor mg, which belong to the calc alkaline high potassium calc alkaline series, and all the samples are peraluminous Granite, trace elements obviously enrich Rb, th, u and loss Sr, Ba, Ti, and the rare earth elements show obvious negative Eu anomaly, which generally shows the characteristics of the crust source granite. Moreover, the late light color rocks in the Niu Tang mining area show the low rare-earth total amount, and the REE distribution pattern is characterized by "Seagull like", and the Yanshan stage W-Sn metallogenic rock mass in other areas of Nanling. The chemical characteristics of the ball are similar. The Huangshan tungsten granite has low Nd (T) (-9.33~-10.58) value and low epsilon HF (T) (-5.9~-10.5) value. The corresponding nd, HF two mode age is 1907~2760ma and 1626~1918ma respectively. It is similar to the isotopic characteristics of the Niu Tang W and cloud head W-Mo ore ore-forming rock, which is formed by the remelting of the paleo crust and the tungsten copper mineralization in the Jie brand mining area. The values of the epsilon Nd (T) (-5.91~-7.92) and the HF (T) (-4.4~-10.7) of the rock mass are negative. The age of the two modes of Nd and HF are 1621~1963ma and 1690~2088ma, respectively, which have the characteristics of the shell source, but the values of the epsilon Nd (T) are relatively high and the values are relatively dispersed, indicating that there are some differences between the source area and the tungsten mineralized rock mass of Shun Huangshan, which may contain some ground. Mantle or new crust material. (3) the source of ore-forming rock mass is an important factor in the formation of different metallogenic elements in the controlled area. The geochemical characteristics of the W-Cu deposit and the Shun Huangshan w deposit, the Niu Tang boundary w deposit and the cloud head W-Mo ore deposit are different, the former is relatively low silicon, high iron, magnesium, calcium and high Nd (T) value. High silicon, characterized by high evolution granites and relatively lower Nd (T) values. This indicates that the high evolutionary granite in the Miao mountain and Yucheng ridge ore area is beneficial to the formation of W and W-Mo deposits, while the Cu-W mineralized and non highly evolving granite and the.W and W-Mo granites are mainly formed by the melting of the ancient basement and the W-Cu mineralized granites. The source area may contain a small amount of mantle (new crust material). The difference in the evolution degree of the magmatic source area and diagenesis may be the main controlling factor for the formation of different metallogenic element combination deposits. (4) the ore-forming fluid of Sijie skarn type W-Cu ore is mainly medium high temperature, low salinity NaCl-H2O-CO_2-CH4 hydrothermal system, and the fluid mixture is its metallogenic element precipitation. The main mechanism of lake deposit is that the ore-forming fluid of W ore of Shun Huangshan is mainly medium and low salinity NaCl-H2O-CO_2-CH4 hydrothermal system, fluid cooling and cooling are the main factors of its metallogenic element precipitation, and fluid immiscibility may also be one of the factors. We analyzed the three different mineralization of siberi skarn W-Cu deposit, scheelite ore and late quartz vein. The fluid inclusions in the pegmatite quartz have a homogeneous temperature peak of 310~330 C, the salinity is 0.18~5.71%NaCleqv, and the Raman spectrum shows the composition of CO_2 and CH4 in the gas, which belongs to the middle and low salinity NaCl-H2O-CO_2-CH4 hydrothermal system, and the homogeneous temperature of the fluid inclusions in the scheelite ore has two peaks, 260~, respectively. 280 C and 320~340 degree C, the salinity is 0.35%~5.56%NaCleqv, which belongs to middle temperature and low salinity. The peak value of the homogeneous temperature of the late quartz vein is 270~300 C, the salinity is 0.18~3.71%NaCleqv, the gas also contains CO_2 and CH4, which belongs to the middle temperature and low salinity category. The homogeneous temperature and salinity of the wolframite ore of the Jie brand W-Cu ore are obviously positive. The related linear relation shows that it has experienced fluid mixing to precipitate the metallogenic element, and observed and analyzed the fluid inclusion characteristics of the three stages of the metallogenic granite, the cloud English rock and the late quartz vein in the Shun Huangshan mining area. The quartz in the rock phase has not seen the molten inclusions in the quartz, and the test pair is mainly fluid inclusions, and the peak value of the homogeneous temperature is 2. 10~240 degree C, with the salinity of 0.18~3.55%NaCleqv, and the homogeneous temperature of fluid inclusions in the stage of the cloud English rock phase, the salinity is similar. It is presumed that it is formed by the transformation of the hydrothermal fluid in the phase of the cloud English rock. At the same time, CO_2 and CH4 are found in the gas of the quartz inclusions in the quartz rock. Therefore, the two stages belong to the middle temperature and low salinity NaCl-H2O-CO_2-CH4 hydrothermal system, and the late quartz vein is homogeneous. The peak temperature is 190~220 C, the salinity is 0.18~3.71%NaCleqv, and the gas composition also contains CO_2 and CH4, which belongs to middle low temperature and low salinity NaCl-H2O-CO_2-CH4 hydrothermal system, while the temperature span of the fluid inclusions in the cloud English rock of the main mineralization stage of the Huangshan Mountain W deposit is larger, but the salinity is in a small range, indicating that it has experienced the cooling and cooling of the fluid. The process leads to the precipitation of metallogenic elements. At the same time, a small amount of rich gas phase and rich liquid phase two inclusions are symbiotic, and the homogeneous temperature of the rich gas phase inclusions is high, which indicates that the fluid immiscibility has been experienced. This may also be one of the factors that cause the precipitation of the metallogenic elements.
【學位授予單位】：中國科學院研究生院(廣州地球化學研究所)
【學位級別】：博士
【學位授予年份】：2016
【分類號】：P612
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本文編號：2066981