陽山金礦田 秦嶺造山帶 花崗斑巖脈 構(gòu)造 控礦地質(zhì)因素
本文關(guān)鍵詞:甘肅文縣陽山金礦田地質(zhì)特征及控礦地質(zhì)因素分析,由筆耕文化傳播整理發(fā)布。
甘肅文縣陽山金礦田地質(zhì)特征及控礦地質(zhì)因素分析
Geological Features and Ore-Controlling Factors of the Yangshan Gold Field in Wen County, Gansu Province
[1] [2] [3] [4] [5] [6] [7]
GUO Junhua, MAO Shidong, CHEN Yanjing, QIN Yan, YANG Fuli, LI Jianzhong and NAN Zhenglu ( 1. The 12th Detachment of Gold Headquarters of China Armed Police Force, Chengdu
[1]中國人民武裝警察部隊黃金第十二支隊,四川成都610036; [2]中國科學(xué)院廣州地球化學(xué)研究所成礦動力學(xué)重點實驗室,廣東廣州510640; [3]中國科學(xué)院研究生院,北京100049; [4]北京大學(xué)造山帶與地殼演化實驗室,北京100871
文章摘要:甘肅文縣陽山金礦田是中國最大的金礦床,最近發(fā)現(xiàn)于西秦嶺的勉略縫合帶附近,它是由賦存于泥盆系三河口群地層中的受文縣弧形構(gòu)造帶控制的類卡林型金礦系統(tǒng)。對陽山礦田安壩礦段鉆探和坑探工程資料的統(tǒng)計表明,,所有金礦體均受安昌河-觀音壩斷裂系統(tǒng)(含主干斷裂和次級斷裂)控制,多數(shù)金礦體定位于斷裂構(gòu)造與泥質(zhì)、粉砂質(zhì)千枚巖的復(fù)合部位,少數(shù)定位于花崗斑巖脈及其接觸帶,說明印支期花崗巖漿活動并不是前人認為的主導(dǎo)金礦化的地質(zhì)條件。結(jié)合區(qū)域地質(zhì)分析,本文認為三河口群及其下伏碧口群等地層在早侏羅世造山事件為陽山金成礦系統(tǒng)提供了成礦流體和物質(zhì),三河口群泥質(zhì)、粉砂質(zhì)千枚巖是成礦流體聚集和成礦金屬卸載的有利空間。沿安昌河-觀音壩斷裂系統(tǒng)侵位的礦前花崗斑巖脈,盡管數(shù)量較少,但也是成礦流體聚集、圈蔽和成礦的有利場所。更為重要的是,花崗斑巖脈與地層之間的能干性具有顯著差異,使接觸帶在后期碰撞造山過程中演化為韌-脆性變形帶,進而成為十分理想的成礦流體循環(huán)、聚集和金礦化空間。
Abstr:The Yangshan gold-field, Wen County, Gansu Province, is the largest gold system in China. It has been recently discovered near the Mian-Lue geosuture zone in the western Qinling Orogen. As a Carlin-like gold-system, the deposit is located in the Wenxian arc-shaped tectonic zone and hosted in the Sanhekou Group of Devonian. Statistics of data from drillings and tunnels in the Anba exploration district of the Yangshan gold-field shows that all the orebodies are controlled by the Anchanghe-Guanyinba fault system comprising of the backbones and subsidiary brit- tle-ductile shear zones or fractures. The majority of orebodies locate in fractured pelitic and silty phyllites, with a minority in the pre-ore Indosinian granite-porphyry dykes or their contact zones, suggesting that the Indosinian granite magmatism was not, as interpreted in previous studies, the dominant factor to cause gold mineralization. Combining with regional geological study, we argue that the Sanhekou Group and its underlying strata such as the Bikou Group provided ore-fluids and metallogenic materials for the Yangshan gold-system during the Early Jurassic orogen- esis, while the pelitic and silty phyllites of the Sanhekou Group provided favorable loci for ore-fluid accumulation and ore-metal discharge. The pre-ore granite-porphyry dykes emplaced along the Anchanghe-Guanyinba fault-system. Despite of their paucity, they could also focus and trap ore-fluids, and host gold orebodies. Moreover, due to great difference in strength between the phyllites and the porphyry dykes, most of the porphyry dyke-phyllite contact zones became brittle-ductile shear zones during collisional orogenesis and favorably accommodated ore-fluid circulating, focusing and gold minerali
文章關(guān)鍵詞:
Keyword::Yangshan gold field Qinling Orogen granite-porphyry dyke structure ore-controlling geological factor
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本文關(guān)鍵詞:甘肅文縣陽山金礦田地質(zhì)特征及控礦地質(zhì)因素分析,由筆耕文化傳播整理發(fā)布。
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