中文摘要：

岔路口矿床是迄今为止在中国东北地区找到的最大规模钼多金属矿床，钼、铅一锌和银的储量分别为124万t、26万t和2773t。考虑到大规模地质勘查工作仍在进行中，金属储量的增加只是个时间问题。钼多金属矿化大都在中一晚侏罗世和早白垩世酸性火山岩和隐爆角砾岩以及燕山期石英斑岩（花岗斑岩）内呈浸染状、细脉状和网脉状产出．并且构成似层状、囊状和“倒扣钟”状矿体。钼多金属矿石主要由辉钼矿、黄铁矿、磁铁矿、方铅矿、闪锌矿、石英、钾长石、萤石和绢云母所组成，其中8件辉钼矿样品的Re-0s同位素等时线年龄为（146．9±0．8）Ma。初步研究结果表明．岔路口矿床无论在产出环境和地质特征方面，还是在矿物种类和元素组合上均可与美国克莱梅克斯钼矿床相对比．属高氟含量斑岩型钼矿床。古大陆内部伸展构造环境中生代多期中酸性岩浆活动为矿床的形成提供了动力、热力和物质来源．隐爆角砾岩带为成矿流体运移和成矿物质堆积提供了空间条件。

英文摘要：

Located at the northernmost comer of the Deerbugan metallogenic bek, the newly found Chalukou deposit is the largest molybdenum polymetallic deposit ever discovered in Northeast China. It contains 1.24 Mt of Mo （metal）, 0.26 Mt of Pb-Zn and 2773 t of Ag. As a part of the evaluation project on the molybdenum deposit, mineral exploration around the Chalukou deposit is still under way. During the Mesozoic Yanshanian orogeny, intense extensional tectonic and igneous activities resulted in the intrusion of large-scale acid volcanic rocks and granitoids at Chalukou and its neighboring areas. The Chalukou granite porphyry and rhyolite porphyry stocks were emplaced in the Jurassic volcano-sedimentary sequence controlled by NE- and NW-trending fault zones. Rock-forming minerals of the two porphyry stocks are mainly quartz, microcline, microperthite and plagioclase associated with minor biotite and sericite. Accessory minerals are magnetite, apatite, zircon, sphene and aUanite. The two porphyry stocks are petrochemically characterized by relatively high SiO2, K20, F, R.b, Yb, U, Th,Y and Yb and obviously low CaO, Fe203＋FeO, MgO, Sr, Ba and REE, with positive ？Nd （t） value. Molybdenum mineralization occurs within the Chalukou porphyry stocks and volcanic rocks as stockwork, veins, veinlets and disseminated blocks. The molybdenum ore consists of pyrite, chalcopyrite, molybdenite, sphalerite, galena, magnetite, pyrrhotite, K-feldspar, fluorite, quartz, sericite and chlorite. As the most important economic molybdenum mineral, molybdenite occurs in the forms of impregnation, radioflake, thin film, aggregated flakes and veinlet. R.e-Os isotopic age dating of eight molybdenite separates from the Chalukou deposit yielded an isochron age of 146.9 ＋ 0.8 Ma and model ages ranging from 146.2 to 149.1Ma with an average value of 147.4Ma. As the Re-Os isochron age is in agreement with field geological evidence, the authors hold that the Re-Os isochron age represents the major ore-forming time of the Chalukou deposit, which