图  1  长江铀矿田大地构造与区域构造图

a—大地构造图(据Hu et al., 2008)；b—长江铀矿田区域构造图(1—第四系；2—寒武系浅变质碎屑岩；3—燕山早期晚阶段花岗岩；4—燕山早期早阶段花岗岩；5—印支晚期花岗岩；6—印支早期花岗岩；7—海西期花岗闪长岩；8—主干断裂/次级断裂；9—铀矿带；10—地质界线；11—铀矿床；据黄国荣等，2012修改)

Figure  1.  Tectonic and regional geologic map of the Changjiang uranium ore field

(a) Tectonic map of the Changjiang uranium ore field (Hu et al., 2008); (b) Regional geologic map of the Changjiang uranium ore field (1-Quaternary system; 2-Epimetamorphic clastic rock of Cambrian; 3-Granite of late stage of early Yanshanian epoch; 4-Granite of early stage of early Yanshanian epoch; 5-Granite of late Indo-Chinese epoch; 6-Granite of early Indo-Chinese epoch; 7-Granodiorite of Variscan epoch; 8-Main fault/secondary fault; 9-Uranium belt; 10-Geologic boundary; 11-Uranium deposit; modified from Huang et al., 2012)

图  2  粤北长江铀矿田地质图(据核工业北京地质研究院(2021)报告编制)

1—第四系；2—燕山晚期细粒二云母花岗岩；3—燕山晚期花岗斑岩；4—燕山晚期闪斜煌斑岩；5—燕山早期第三阶段细粒黑云母花岗岩；6—燕山早期第一阶段不等粒黑云母花岗岩；7—燕山早期第一阶段中粒黑云母花岗岩；8—印支期第三阶段中粒小斑状二云母花岗岩；9—印支期第二阶段中粒斑状黑云母二长花岗岩；10—碱交代岩；11—主要断层；12—次级断层；13—碱性岩脉；14—地质界线；15—岩性界线；16—铀矿带编号；17—大型铀矿床；18—中/小型铀矿床

Figure  2.  Geologic map of the Changjiang uranium ore field, northern Guangdong (adapted from Beijing Research Institute of Uranium Geology, 2021)

1- Quaternary system; 2-Fine grained micaceous granite of late Yanshanian epoch; 3-Granite porphyry of late Yanshanian epoch; 4-Spessartite of late Yanshanian epoch; 5-Fine grained biotite granite of third stage of early Yanshanian epoch; 6-Unequal-grained biotite granite of first stage of early Yanshanian epoch; 7-Medium-grained biotite granite of first stage of early Yanshanian epoch; 8-Medium-sized small porphyritic biotite granite of third stage of Indo-Chinese epoch; 9-Medium-grained porphyritic biotite adamellite of second stage of Indo-Chinese epoch; 10-Alkali netasomatic rock; 11-Main fault; 12-Second-order fracture; 13-Alkaline dike; 14-Geologic boundary; 15-Lithologic boundary; 16-Number of uranium belt; 17-Large uranium deposit; 18-Medium/small sized uranium deposit

图  3  长江矿田棉花坑断裂和油洞断裂线性负地貌影像图

Figure  3.  Remote image showing the liner negative landform of the Mianhuakeng fault and Youdong fault in the Changjiang ore field

图  4  棉花坑断裂旁侧次级裂隙构造特征平面照片

a—棉花坑断裂旁侧的北东向裂隙，仅为简单裂隙，未见矿化蚀变，Z74点；b—c—棉花坑断裂旁侧的近南北向裂隙，Z74点；d—f—棉花坑断裂北旁侧近南北向裂隙，可见有猪肝色硅化及晚期白色石英脉，Z29点

Figure  4.  Pictures showing the second-order fracture on the side of the Mianhuakeng fault

(a) Picture showing the simple NE-trending fracture approaching the Mianhuakeng fault with non-alteration at Point Z74; (b-c) Pictures showing the nearly SN-trending fracture approaching the Mianhuakeng fault at Point Z74; (d-f) Pictures showing the nearly SN-trending fracture on the north side of the Mianhuakeng fault with purplish red silicification and late white calcite vein at Point Z29

图  5  棉花坑断裂破碎带剖面图(Z76点)

1—第四系残坡积；2—花岗岩；3—压扭性构造角砾岩；4—片理化带；5—断层；6—硅化带(石英脉)

Figure  5.  Section of fracture zone of the Mianhuakeng fault in the Changjiang uranium ore field, northern Guangdong(Point Z76)

1-Quaternary residual slope; 2-Granite; 3-Compresso-shear tectonic breccia; 4-Foliated belt; 5-Fault; 6-Silicified zone(quartz vein)

图  6  油洞村北东电站旁油洞断裂旁侧裂隙与铀矿化特征(Z28点，57号铀矿带)

1—花岗岩；2—石英脉；3—节理裂隙；4—微细石英脉；5—伽玛异常及异常值/ (nC/ (kg ·h))；6—产状

Figure  6.  Sketch showing the fracture and uranium mineralization near the Youdong fault

1-Granite; 2-Quartz vein; 3-Joint and fracture; 4-Fine quartz vein; 5-Gamma anomaly and its value/ (nC/ (kg ·h)); 6-Attitude

图  7  油洞断裂旁侧铀矿化地质剖面图(Z67点)

1—碎裂花岗岩；2—节理；3—黄褐色硅化带；4—猪肝色硅化带；5—伽玛异常值/nC/ (kg ·h)；6—产状

Figure  7.  Sketch showing the fracture and uranium mineralization near the Youdong fault (Point Z67)

1-Cataclastic granite; 2-Joint; 3-Tawny silicified zone; 4-Purplish red silicified zone; 5-Gamma anomaly and its value/nC/ (kg ·h); 6-Attitude

图  8  油洞断裂旁侧铀矿化地质剖面图(Z23点)

1—碎裂花岗岩；2—晚期石英脉；3—节理；4—伽玛异常等值线；5—硅化；6—弱铀矿化黄褐色硅化带(30 nC/ (kg ·h)≤伽玛值≤40 nC/ (kg ·h))；7—强铀矿化(伽玛值≥40 nC/ (kg ·h))猪肝色硅化带；8—伽玛异常值/ (nC/ (kg ·h))；9—产状；10—水池

Figure  8.  Sketch showing the fracture and uranium mineralization near the Youdong fault (Point Z23)

1-Cataclastic granite; 2-Late quartz vein; 3-Joint; 4-Gamma anomaly isoline; 5-Silicification; 6-Tawny silicified zone with weak uranium mineralization(30 nC/ (kg ·h)≤gamma value≤40 nC/ (kg ·h)); 7-Purplish red silicified zone with intensive uranium mineralization; 8-Gamma anomaly value/ (nC/ (kg ·h)); 9-Attitude; 10-Cistern

图  9  油洞村油洞断裂及基性岩脉与铀矿化的关系平面素描图(Z32点)

1—花岗岩；2—基性岩脉；3—石英脉；4—片理化；5—断层；6—裂隙节理；7—赤铁矿化界线；8—赤铁矿化；9—裂隙产状；10—放射性异常辐射值/ (nC/ (kg ·h))；11—弱铀矿化(50 < γ≤200 nC/ (kg ·h))；12—中等铀矿化(200 < γ≤300 nC/ (kg ·h))；13—强铀矿化(300 < γ≤800 nC/ (kg ·h))

Figure  9.  Picture and sketch showing the relation of the Youdong fault and basic dike to uranium mineralization

1-Granite; 2-Basic dike; 3-Quartz vein; 4-Foliation; 5-Fault; 6-Joint and fracture; 7-Range of hematite mineralization; 8-Hematite mineralization; 9-Attitude of fracture; 10-Gamma Anomaly value/ (nC/ (kg ·h)); 11-Weak uranium mineralization (50 < γ≤200 nC/ (kg ·h)); 12-Moderate uranium mineralization (200 < γ≤300 nC/ (kg ·h)); 13-Intensive uranium mineralization (300 < γ≤800 nC/ (kg ·h))

图  10  长江铀矿田油洞岩体内不同方向的局部韧性变形

a—学堂垇一带，近南北向韧性变形带，原岩为花岗岩，镜头指向西下，D2100点；b—学堂垇一带，近东西向韧性变形带，原岩为花岗岩，镜头指向南下，D2100点北；c—学堂垇一带，近东西向韧性变形带，原岩为花岗岩，镜头指向南下，D2100点北；d—长江1号科学钻孔，68回次，陡倾角韧性变形带；e—图d局部放大；f—9号带南段ZK15-3钻孔220 m附近缓倾角韧性变形带

Figure  10.  Pictures showing ductile deformations of different directions in several places of the Youdong granite body

(a) Picture showing the nearly SN-trending ductile deformation developed in the granite at Point D2100, Xuetang' ao; (b) Picture showing the nearly EW-trending ductile deformation developed in the granite at the north of Point D2100, Xuetang' ao; (c) Picture showing the nearly EW-trending ductile deformation developed in the granite at point D2100, Xuetang' ao; (d) Picture showing steep-dip ductile deformation developed in the granite ore from the 68^th drilling trip of the Changjiang No.1 scientific drilling hole; (e) Local magnification of Fig. 10d; (f) Picture showing gentle-dip ductile deformation developed in the granite ore from 220-m drilling depth of the ZK15-3 drilling hole, southern part of No.9 uranium ore belt

图  11  长江铀矿田构造演化图

1—含矿断裂；2—铀矿带；3—基性岩脉；4—断层(不含矿)；5—压性断裂/压扭性断裂；6—张性断裂/张扭性断裂；7—主应力及其方向

Figure  11.  Evolution model of the structures in the Changjiang uranium ore field

1-Ore-bearing fault; 2-Uranium ore belt; 3-Basic dike; 4-Fault (ore-free); 5-Compressive/compresso-shear fault; 6-Extensional/tenso-shear fault; 7-Principal stress and its direction