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本文讨论湘东南和粤北地区的花岗岩型铀矿化、这些铀矿化形成于地洼余动期(46—87百万年)、 1、铀源岩主要是印支期花岗岩类,现存铀含量不高(平均约11×10~(-6)),通过原生黑云母多色晕研究表明,原始铀丰度较高; 2、本区印支期和印支期以前的花岗岩类,在地洼激烈期(燕山期)受了不同程度变质作用影响,在地穹系变质作用强烈,局部产生再生岩浆作用,在地洼系变质作用微弱或基本未受变质作用影响; 3、地洼系中印支期和印支期以前的花岗岩类,普遍受到了强烈的中—低温蚀变(叶绿泥石化、白云母化、绢云母化和水云母化等),地穹系中由于前进变质作用影响,上述蚀变减弱至消失,黑云母化——黑云母重结晶作用广泛发育; 4、铀活化转移主要依赖于深部热流体、变质热液和大气成因淋滤水形成的混合热液。它主要形成于地洼激烈期后,其物理化学参数是:t=105—250℃,pH=6.27—7.3,Cl~-≥So_4~(-2)≥HCo_3~->F~-,Ca~(2+)>Mg~(2+)≥Na~+>K~+稳定同位素组成变化大(脉石英和碳酸盐中δ~(1(?))OH_2O=+5.5—-15.5‰,平均-4.04‰;碳酸盐中δ~(13)C PDC=-5—-9‰,平均-6.5‰;硫化物中δ~(34)S=-30—+20‰,平均值近于零; 5、混合热液形成于地穹深部,汇聚于地洼浅部,并常使白垩—第三系红层硅化退色。因此,铀矿化主要分布于地洼系。
This paper discusses granitoid-type uranium mineralization in the southeastern part of Hunan and northern Guangdong. These uranium mineralizations formed in the dipping period of the earthworm (46-87 million years). 1 The uranous source rocks are mainly Indosinian granites and the existing uranium (About 11 × 10 ~ (-6)) on average. The studies on multicolour of primary biotite indicate that the abundances of the original uranium are high. 2. The Indosinian and Indosinian granites in this area were characterized by The depression period (Yanshanian period) was affected by metamorphism to varying degrees, strong metamorphism in the dome and regenerative magmatism locally, and weak or almost no metamorphism in the depression depression. 3) The Meso-Indosinian and pre-Indosinian granites were generally subjected to moderate-low temperature alteration (chloritlization, muscovite, sericitization, and micaization, etc.), with progressive metamorphism The alteration weakened to disappear, and the biotitization-biotite recrystallization developed widely. (4) Activation and transfer of uranium mainly depend on the mixed hydrothermal fluid formed by the deep hydrothermal fluid, metamorphic hydrothermal fluid and atmospheric formation leaching water. It is mainly formed after the intense geothermal period, its physical and chemical parameters are: t = 105-250 ℃, pH = 6.27-7.3, Cl ~ -≥So_4 ~ (-2) ≥HCo_3 ~ -> F ~ (2 +)> Mg 2+ (2+) ≥Na ~ +> K ~ + stable isotopic compositions vary widely (δ ~ (1) 脉 OH 2 O = 5.5 ~ 15.5 ‰ in vein quartz and carbonate, -4.04 ‰; δ ~ (13) C PDC = -5--9 ‰ and -6.5 ‰ in carbonate; δ ~ (34) S = -30- + 20 ‰ in sulfide, the average value is close to zero 5) The mixed hydrothermal fluid formed in the deep dome of the earth and converged to the shallow part of the dike, and often led to the fossilization of the chalk in the Cretaceous-Tertiary red. Therefore, uranium mineralization was mainly distributed in the dike depression.