CAJ | 학술논문

江西省浒坑钨矿是一个大型石英脉黑钨矿矿床,含矿石英脉除了块状石英脉以外,还大量发育条带状石英脉.本文针对条带状石英脉进行了专门研究,认为条带状石英脉实质上是韧性剪切带,以透入性发育的剪切面理和拉伸线理、剪切透镜体、剪切分异条带普遍发育为特色.剪切带岩石以石英质糜棱岩为主,具有丰富的塑性变形显微构造特征.显微剪切指向构造统计表明,东西向和北西向脉组的运动方式均以左旋正滑为主,近水平脉组则以正滑为主.北西向韧性剪切带的新生绢云母40Ar-39Ar坪年龄为140.3±1.0 Ma,相应的等时线年龄为139.6±2.4 Ma;而东西向韧性剪切带绢云母40Ar-39Ar坪年龄则比较复杂,高温阶段年龄可能受到成矿期白云母残斑的影响,中温阶段的表观年龄和总气体年龄更接近前一样品的坪年龄.据此认为韧性剪切变形的年龄为140 Ma左右,韧性变形发生在成岩和成矿之后.条带状石英脉系块状石英脉韧性剪切改造而成,推测其形成主要与晚期补充岩体的斜向上侵作用有关,但更为合理的模式需要更多资料的进一步证实.
강서성호갱오광시일개대형석영맥흑오광광상,함광석영맥제료괴상석영맥이외,환대량발육조대상석영맥.본문침대조대상석영맥진행료전문연구,인위조대상석영맥실질상시인성전절대,이투입성발육적전절면리화랍신선리、전절투경체、전절분이조대보편발육위특색.전절대암석이석영질미릉암위주,구유봉부적소성변형현미구조특정.현미전절지향구조통계표명,동서향화북서향맥조적운동방식균이좌선정활위주,근수평맥조칙이정활위주.북서향인성전절대적신생견운모40Ar-39Ar평년령위140.3±1.0 Ma,상응적등시선년령위139.6±2.4 Ma;이동서향인성전절대견운모40Ar-39Ar평년령칙비교복잡,고온계단년령가능수도성광기백운모잔반적영향,중온계단적표관년령화총기체년령경접근전일양품적평년령.거차인위인성전절변형적년령위140 Ma좌우,인성변형발생재성암화성광지후.조대상석영맥계괴상석영맥인성전절개조이성,추측기형성주요여만기보충암체적사향상침작용유관,단경위합리적모식수요경다자료적진일보증실.
Hukeng tungsten deposit is a large scale quartzs-veins-type tungsten deposit which locates at the Wugong Mountain in the west of Jiangxi Province. Besides the massive structure,the banded structure occurs widely in the ore-bearing quartz veins. Detailed field work and microscope research reveal that these banded quartz veins are actually ductile shear zones showing the characteristics of penetrative shear foliation,stretching lineation,shear lens and fractionated strip. The rock of the shear zone is quartz mylonite which is rich in plastic microstructure. The survey and statistic of micro-shearing direction-pointing structures indicate that the moving direction of both EW and NW-trending ductile shear zones are sinistral normal slipping,and near horizontal one,normal slipping. 40Ar-39Ar dating of new-generated sericites from mylonite in the NW-trending shear zone yields a plateau age of 140.3±1.0 Ma and an isochron age at 139.6±2.4 Ma respectively.But the plateau ages of EW-trending shear zone are complicated,as the high-temperature stage plateau age may be affected by muscovite remnant phenocryst which is formed in mineralization stage.The medium-temperature stage total gas age and apparent age are more close to the age of plateau age of sample HK121.It is concluded that the age of ductile shearing is about 140 Ma,indicating that ductile shearing deformation occurs after petrogenesis and mineralization.The banded quartz veins are formed by the ductile shearing of massive quartz veins.The formation mechanism of the ductile shearing may be related to sidelong intrusion of the later supplementary magma,but more reasonable model will be approved by further study and data.