ABSTRACT

North China (NC) is a region recording a long and complex geological history spanning from the Archaean to Cenozoic. This included magmatism, sedimentation, metamorphism, and deformation, demonstrating that the region is not a craton. To date, few studies have considered the links between multiple deformation events, emplacement of granites, and the deposition of gold deposits during the Mesozoic evolution of northeastern NC coeval with deformation in the Central China Orogen. The Malanyu area is a well-exposed part of NC, where almost continuous sedimentation and multiple deformation events are recorded. Long-lived magmatism broadly extended between ca. 220 and 118 Ma and is concentrated in the hinge zone of the east-trending Malanyu Anticline, which is a large-scale anticline deformed multiple times. Timing relationships between sedimentation, deformation, and magmatism show that the structure must be between 250 and 220 Ma. The upper limit corresponds to the closure of the Palaeoasian Ocean during the onset of collision between the Central Asian Orogen and NC to the south. Magmatism in the anticline’s hinge zone can be subdivided into three magmatic events between ca. 220–214, 200–143 and 128–118 Ma separated at ca. 212–202 Ma and ca. 140–130 Ma, and these periods of magmatic hiatus correspond to unconformities in the sedimentary succession. The oldest granite in the area is ca. 220 Ma limiting the age of the anticline between ca. 250 and 220 Ma. The gold mineralisation was emplaced in structurally prepared sites along faults and anticline hinge zones and broadly contemporaneous with the magmatic events. The gold assays of samples collected for this study show that the hinge zone of the Malanyu Anticline, around the intersection of the Myun-Xifengkou-Qinglong Shear Zone and Baiyangyu Fault, the area west of the Dashan Granite, and the northwestern part of the study area are prospective for gold.

摘要

华北 (NC) 是一个记录了从太古代到新生代漫长而复杂的地质历史的地区。这包括岩浆作用、沉积作用、变质作用和变形作用，表明该地区不是克拉通。迄今为止，很少有研究考虑在华中造山带变形的北卡罗来纳东北部中生代演化过程中多次变形事件、花岗岩的侵位和金矿床沉积之间的联系。马兰峪地区是北卡罗来纳州出露良好的地区，记录了几乎连续的沉积和多次变形事件。长寿命的岩浆作用广泛地延伸到约 。220、118 Ma，集中在东向马兰峪背斜的铰接带，是一个多次变形的大型背斜。沉降之间的时间关系，变形和岩浆作用表明该结构必须在 250 到 220 Ma 之间。上限对应于中亚造山带和北卡罗来纳南部碰撞开始期间古亚洲洋的闭合。背斜铰链带中的岩浆活动可以细分为大约在 220-214、200-143 和 128-118 Ma 分离于约 212–202 Ma 和约 140-130 Ma，这些岩浆中断时期对应于沉积序列中的不整合面。该地区最古老的花岗岩大约是。220 Ma 限制了大约 220 Ma 之间的背斜年龄。250 和 220 毫安。金矿化位于沿断层和背斜铰链带的构造准备好的地点，并且与岩浆事件大致同时发生。