辽南新房变质核杂岩的发现及地质意义

根据宏观与微观构造测量，揭示出在辽宁南部新房地区存在一个变质核杂岩构造，即新房变质核杂岩。该核杂岩具有典型的3层结构：上盘为新元古代—古生代弱变形沉积岩层，下盘是新太古代糜棱岩、片麻杂岩和中生代花岗质侵入岩体，中间是拆离断层带由不同层次构造岩构成。拆离断层带形态为向北西开口的反“C”型，产状较缓，倾向分别向西、向南、向东倾斜，线理产状240°～290°∠12°～30°。运动方向为上盘相对下盘由北东东向南西西运动，结合区域岩浆活动性及其测年资料等综合分析，新房变质核杂岩形成于早白垩世，与辽南金州变质核杂岩在几何学、运动学极性和形成时间等方面具有很多相似性，形成于同一动力学背景。该变质核杂岩的厘定不仅为阐明华北克拉通中生代岩石圈减薄过程及岩石圈的力学和流变学属性提供依据，而且为下一步新房金矿的勘查指明了找矿方向。

Discovery and geological implication of Xinfang metamorphic core complex in southern Liaoning

On the basis of comprehensive analysis of macroscopic and microscopic structural data, combined with the regional magmatic activity and dating data, it is revealed that there is another new Metamorphic Core Complex （MCC） structure in the Xinfang area of southern Liaoning, that is Xinfang MCC. The core complex has a typical three-layer structure：the upper plate is a Neo-Proterozoic-Paleozoic weakly deformable sedimentary rock; the footwall is Neo-Archaean mylonite, complex gneiss and Mesozoic granitic intrusive rock; in the middle is a detachment fault zone with different types of fault rocks. The disconnection fault zone was of the reverse “C” type with a north-west opening, with a relatively slow attitude and a tendency to tilt to the west, south and east, respectively, with a lineation attitude of 240°～290°∠12°～30°. The direction of motion is top-to-the WSW, combined with the comprehensive analysis of regional magmatic activity and dating data, Xinfang MCC was formed in the Early Cretaceous, which has the same geometry, kinematic polarity and formation time as Jinzhou MCC in southern Liaoning, and is formed in the same dynamic background. The determination of the metamorphic core complex not only provides a basis for elucidation of the thinning process of Mesozoic lithosphere and its mechanical and rheological properties in the North China Craton, but also points out the prospecting direction for the next exploration of the new house gold mine.