本文選題：桐村礦區(qū) + 磷灰石�。� 參考：《中國地質大學(北京)》2015年碩士論文

【摘要】：桐村斑巖鉬(銅)礦床位于江紹拼合帶西南端,處于欽州-錢塘結合帶內,鄰近江南背斜,在欽州-杭州重點找礦帶東段。通過野外調研和觀察,總結并描述了研究區(qū)的基本地質特征,利用磷灰石和鋯石進行裂變徑跡測試,通過分析裂變徑跡長度分布和年齡分布,對礦區(qū)進行熱歷史模擬,并分析了礦床的隆升剝蝕情況。取得認識如下:礦區(qū)主要見花崗巖、花崗巖閃長巖、和角巖,偶見石英巖;主要的含礦巖體有蝕變花崗巖和角巖;輝鉬礦以細脈浸染狀、黃鐵礦和黃銅礦以星點狀或團塊狀富集于巖體和礦脈中,巖體富集大量的含礦石英脈;礦床蝕變以青磐巖化為主,巖體中心向外依次是鉀化硅化-青磐巖化(絹云母化)—高嶺土化,其中礦化石英脈主要集中在青磐巖化帶。分析巖體中磷灰石裂變徑跡長度分布可知,其長度范圍在11.9±2.4μm~13.2±2.0μm之間,相對較為集中,磷灰石裂變徑跡長度分布直方圖有兩種類型,深部樣品為無擾動基底型,淺部出現雙峰型,表明桐村礦區(qū)磷灰石樣品受到構造熱活動影響而表現為兩種分布狀態(tài),巖體整體受到兩期熱事件的作用,但巖體核部的樣品則表現為簡單的冷卻過程。鋯石裂變徑跡年齡的范圍在109-143 Ma之間,磷灰石裂變徑跡年齡范圍在17-31 Ma之間,為正態(tài)分布,其峰值年齡分別為137Ma和22Ma。利用He FTy軟件對樣品進行熱歷史模擬,得到時間-溫度演化曲線,樣品冷卻軌跡相似,先進入冷卻期,然后緩慢冷卻期,最后進入加速冷卻期。利用礦物對法分析剝蝕情況,巖體形成于晚侏羅世,從早白堊世-新近紀,剝蝕速率為0.0238km/Ma,剝蝕量為H1=2.732km,其中鋯石裂變徑跡與高程關系顯示鋯石記錄了該時期的沉積信息,從新近紀-第四紀,巖體剝蝕速率為0.0383 km/Ma,剝蝕量為H2=0.842km,在45~25Ma期間和15~0.1Ma期間有兩次明顯的抬升,兩次的冷卻速率分別為3.75~5℃/km和3.21~6.67℃/km。巖體自137Ma至今,累計剝蝕量為3.579km。巖體的兩次主要抬升剝蝕情況與華南地塊燕山期和喜馬拉雅階段區(qū)域構造作用相吻合。
[Abstract]:The Tongcun porphyry molybdenum (copper) deposit is located at the southwest end of the Jiangshao assemblage belt, located in the Qinzhou-Qiantang junction belt, adjacent to the Jiangnan anticline, and located in the eastern section of the Qinzhou-Hangzhou key ore prospecting belt. Through field investigation and observation, the basic geological characteristics of the study area are summarized and described. The fission track is tested by apatite and zircon, and the thermal history of the mine is simulated by analyzing the length distribution and age distribution of the fission track. The uplift and denudation of the deposit are analyzed. They are: granite, granite diorite, and hornstone, occasionally quartzite; major ore-bearing rock bodies are altered granite and hornstone; molybdenum is disseminated in the vein, Pyrite and chalcopyrite are enriched in the rock mass and vein in the form of star or lump, and the ore-bearing veins are enriched in the rock mass. The center of the rock mass is in the order of potassium silicification-Qingiranlitization (sericite)-kaolinization, in which the mineralized quartz vein is mainly concentrated in the Qingiranlitization zone. By analyzing the length distribution of apatite fission track in rock mass, it can be seen that the length range of apatite fission track is between 11.9 鹵2.4 渭 m and 13.2 鹵2.0 渭 m, which is relatively concentrated. There are two types of apatite fission track length distribution histogram. The results show that the samples of apatite in Tongcun mining area are affected by tectonic thermal activity in two distribution states, the whole rock mass is affected by two thermal events, but the sample in core of rock mass shows a simple cooling process. Zircon fission track ages range from 109 to 143 Ma, apatite fission track ages range from 17 Ma to 31 Ma, which are normal distribution, their peak ages are 137 Ma and 22 Ma, respectively. He FTy software was used to simulate the thermal history of the sample, and the time-temperature evolution curve was obtained. The cooling trajectory of the sample was similar, which entered the cooling period first, then slowly, and finally the accelerated cooling period. From early Cretaceous to Neogene, the denudation rate is 0.0238km / Maand the denudation amount is H1 / 2.732km. The relationship between zircon fission track and height indicates that the sedimentary information of this period is recorded by the relationship between zircon fission track and height. From Neogene to Quaternary, the denudation rate of rock mass is 0.0383 km / Ma and the denudation amount is H _ 2O _ (0.842) km. There are two distinct uplift during 45~ 25Ma and 150.1Ma, the cooling rate of which is 3.75 ~ 5 鈩，

本文編號：2055297