發(fā)布時間：2018-04-26 11:49

  本文選題：成礦流體 + 構(gòu)造控礦��； 參考：《巖石學(xué)報》2017年07期

【摘要】：西南三江中段蘭坪地區(qū)經(jīng)歷了復(fù)雜的碰撞造山過程,導(dǎo)致成礦時間長、強(qiáng)度大、作用多樣,復(fù)合疊加成礦突出;碰撞造山時空演化格架和成礦作用已有深入探索,而疊加成礦作用及其對碰撞造山過程的響應(yīng),構(gòu)造控礦樣式,及金屬富集機(jī)理尚需研究。本文以碰撞造山過程與成礦系統(tǒng)研究為基礎(chǔ),選取金頂和金滿等礦床為重點解剖對象,以盆地鹵水和熱液鉛鋅銅銀成礦作用為主線,利用鋯石LA-ICP-MS U-Pb和流體包裹體測試分析手段,解析蘭坪盆地構(gòu)造-流體-成礦系統(tǒng)。利用鋯石U-Pb同位素定年獲得蘭坪盆地西側(cè)片麻質(zhì)花崗巖和二長花崗巖的上交點年齡和加權(quán)平均年齡為1067±20Ma和206±1Ma,分別代表了基底巖石前寒武時期變質(zhì)事件的年齡,以及昌寧-孟連古特提斯洋后碰撞造山事件的年齡。在此基礎(chǔ)上,構(gòu)建了蘭坪盆地的前寒武盆地基底形成、中二疊世-中三疊世前陸盆地、晚三疊世裂谷盆地、侏羅紀(jì)-白堊紀(jì)坳陷盆地、古新世-早漸新世前陸盆地和晚漸新世-中新世走滑拉分盆地等復(fù)雜的轉(zhuǎn)化過程。三江特提斯蘭坪盆地發(fā)育3個與碰撞造山盆地有關(guān)的Pb-ZnCu-Ag-Au-Sb-Hg成礦系統(tǒng):(1)中低溫?zé)嵋好}型Cu-Ag多金屬成礦系統(tǒng),以金滿-連城銅鉬礦床為代表。成礦銅和鉛鋅礦化兩期疊加,集中于早始新世(56~46Ma)和漸新世-中新世(32~21Ma)。成礦流體鹽度變化于0.88%~20.51%NaC leqv之間,成礦溫度較低,通常在210~270℃,顯示以低溫高鹽度的盆地鹵水為主的特征,可能受到來自富CO2的變質(zhì)流體影響;(2)淺成低溫?zé)嵋篠b-Au-Hg-As多金屬成礦系統(tǒng),以筆架山銻礦床為代表。成礦時間集中于中-晚始新世。成礦流體鹽度6.0%NaC leqv,成礦溫度較低,通常在145~200℃,顯示以大氣降水為主的特征;(3)密西西比河谷型Pb-Zn多金屬成礦系統(tǒng),以金頂超大型鉛鋅礦床為代表。成礦時間集中于32~21Ma之間。成礦流體鹽度變化于1.6%~18%NaC leqv之間,成礦溫度較低,通常在80~190℃,顯示以低溫高鹽度的盆地鹵水為主的特征,可能有大氣降水的貢獻(xiàn)。文章最后解析了蘭坪盆地構(gòu)造-流體-成礦過程。研究對蘭坪地區(qū)盆地鹵水 巖漿熱液型鉛鋅銅銀成礦系統(tǒng)認(rèn)識,為大陸碰撞過程及疊加成礦作用進(jìn)一步研究提供理論支撐。
[Abstract]:The Lanping area in the middle part of the Sanjiang River in the southwest has experienced a complicated collision orogenic process, which has resulted in a long metallogenic time, a large strength, a variety of functions, and a combination of superimposed metallogenic outburst, and the temporal and spatial evolution framework of collision orogeny and the metallogenic process have been deeply explored. However, the superposition mineralization and its response to collision orogeny, structural ore-controlling style, and the mechanism of metal enrichment need to be studied. Based on the study of collision orogenic process and metallogenic system, the Jinding and Jinman deposits are selected as the main anatomical objects, the brine and hydrothermal lead-zinc-copper-silver mineralization in the basin are taken as the main line, and zircon LA-ICP-MS U-Pb and fluid inclusion testing and analysis methods are used. Analysis of tectonic-fluid-metallogenic system in Lanping Basin. Using zircon U-Pb isotopic dating, the upper intersection age and weighted mean age of granitic granites and monzomorphic granites on the west side of the Lanping basin are 1067 鹵20Ma and 206 鹵1 Ma, respectively, representing the ages of the Precambrian metamorphic events in the basement rocks. And the age of the post-collision orogenic events in Changning-Montaigne. On this basis, the Precambrian basin basement of Lanping basin, the Middle Permian-Middle Triassic Foreland basin, the late Triassic rift basin, the Jurassic-Cretaceous depression basin, the middle Permian-Middle Triassic Foreland basin, the late Triassic rift basin and the Jurassic Cretaceous depression basin were constructed. Paleocene-early Oligocene Foreland basin and late Oligocene-Miocene strike-slip pull-apart basin. In Sanjiang Tethys Lanping basin, there are three Pb-ZnCu-Ag-Au-Sb-Hg metallogenic systems related to collisional orogenic basins: (1) Cu-Ag polymetallic ore-forming systems of hydrothermal vein type, represented by the Jinmen-Liancheng Cu-Mo deposit. The mineralization of copper and lead-zinc is superimposed in the early Eocene (56 ~ 46 Ma) and Oligocene ~ Miocene ~ (32) ~ (21) Ma. The salinity of ore-forming fluid varies between 0.88%~20.51%NaC leqv and the ore-forming temperature is relatively low, usually at 210 ~ 270 鈩，

本文編號：1805896