CAJ | 학술논문

通过野外地质调查、室内(超)显微构造观测和构造岩石组构分析等方法厘定了煎茶岭地区北西西向和北东向两条韧性剪切带,前者出露于研究区的北部,后者出露于研究区的南部,两者交汇于煎茶岭,无论沿走向还是顺倾向均呈舒缓波状.韧性剪切带内发育糜棱岩系列、构造片岩、荚片构造、S-C面理、旋转碎斑系、A型褶皱、亚颗粒、位错弓弯、位错列、位错网等宏观和(超)显微构造特征,结合构造岩中石英光轴优选方位型式等证明两韧性剪切带呈共轭产出,至少经历了三期活动:中元古代晚期,北西西向脆韧性剪切带为压扭性右行剪切,北东向脆韧性剪切带为压扭性左行剪切,σ_1≈282°∠24°,古应力值约59.1MPa;加里东期,前者为张扭性右行剪切,后者为张扭性左行剪切,σ_1≈344°∠78°,古应力值约86.5MPa,超基性岩体以岩墙扩展式侵入到韧性剪切带内,预测北东向韧性剪切带深部还存在一定规模的超基性岩体,是今后寻找与超基性岩有关矿产的重要靶区;海西期,随着脆性程度进一步增加,北西西向韧脆性剪切带经历了压扭性左行剪切,北东向韧脆性剪切带经历了压扭性右行剪切,σ_1≈120°∠20°,古应力值约116.3MPa,花岗斑岩体以气球膨胀式侵位.韧性剪切带对金镍矿有重要控制作用.
통과야외지질조사、실내(초)현미구조관측화구조암석조구분석등방법전정료전다령지구북서서향화북동향량조인성전절대,전자출로우연구구적북부,후자출로우연구구적남부,량자교회우전다령,무론연주향환시순경향균정서완파상.인성전절대내발육미릉암계렬、구조편암、협편구조、S-C면리、선전쇄반계、A형습추、아과립、위착궁만、위착렬、위착망등굉관화(초)현미구조특정,결합구조암중석영광축우선방위형식등증명량인성전절대정공액산출,지소경력료삼기활동:중원고대만기,북서서향취인성전절대위압뉴성우행전절,북동향취인성전절대위압뉴성좌행전절,σ_1≈282°∠24°,고응력치약59.1MPa;가리동기,전자위장뉴성우행전절,후자위장뉴성좌행전절,σ_1≈344°∠78°,고응력치약86.5MPa,초기성암체이암장확전식침입도인성전절대내,예측북동향인성전절대심부환존재일정규모적초기성암체,시금후심조여초기성암유관광산적중요파구;해서기,수착취성정도진일보증가,북서서향인취성전절대경력료압뉴성좌행전절,북동향인취성전절대경력료압뉴성우행전절,σ_1≈120°∠20°,고응력치약116.3MPa,화강반암체이기구팽창식침위.인성전절대대금얼광유중요공제작용.
Based on the methods of field geological survey, ultramicrostructural and microstructural observation in a laboratory and petrofabric analysis of tectonites, two ductile shear zones trending in NWW and NE in the Jianchaling area are determined. The former occur in the northern part of the study area while the latter in the southern area and they intersect each other in Jianchaling with a gentle wave-like shape in both strikes and dips. The macroscopical, ultramicrostructural and microstructural characteristics of the ductile shear zones, such as mylonite series, tectonic schist, schist beanpod-like structure, S-C foliation, rotation broken spot series, A-type folds, subparticles, dislocation bowing-out, dislocation array, dislocation net and the preferred orientation form of quartz c-axisect in the tectonites, prove that the two ductile shear zones are of conjugation, and experienced at least three periods. Namely, In the late Mesoproterozoic, the NWW brittle-ductile shear zone underwent dextral compresso-shearing while the NE sinistral compresso-shearing σ_1≈282°∠24°, the paleostress is estimated at about 59.1MPa. In the Caledonian period, the former underwent dextral tension-shearing while the latter sinistral tension-shearing σ_1≈344°∠78°, the paleostress is estimated at about 86.5MPa. The ultrabasic plutons intruded into the ductile shear zones by the form of dyke expansion. It is deduced that there exist a fairly large scale of ultrabasic pluton in the depths in the NE ductile shear zone, which is the essential metallogenic target area related to the ultrabasic rocks. And in the Hercynian period, with the further increase in the degree of brittleness, the NWW ductile-brittle shear zone underwent sinistral compresso-shearing while the NE dextral compresso-shearing σ_1≈120°∠20°, the paleostress is estimated at about 116.3MPa. The granite porphyry was emplaced by the form of balloon expansion. The ductile shear zones play a very important role in controlling gold and nickel mineralizations in the study area.