河北青山口岩体锆石U-Pb年龄及其地质意义

青山口岩体位于冀东地区,为研究其成岩时代及地质意义,本文选取青山口花岗岩为研究对象,采用SHRIMP锆石U-Pb法对青山口岩体花岗岩样本进行年代学分析。结果可知,QSK-1和QSK-2形成年龄分别为(200.5±2.9)Ma；(202.1±4.6)Ma,确定了青山口岩体位于印支末-燕山早期造山阶段。同时,结合前人已取得的相关成果,发现青山口岩体花岗岩与所处冀东地区EW向构造带的岩体的形成主要受华北地区南北向主应力场的作用。且青山口等NW向花岗岩岩体属于同一时期岩浆活动产物,同属燕山造山阶段。这为研究冀东地区造山构造的演化过程以及该区找矿工作提供参考。

Zircon U-Pb Age of Qingshankou Pluton in Hebei Province and Its Geological Significance

Qingshankou granites are located in eastern Hebei province. In order to study the diagenetic age and geological significance of Qingshankou granites, this paper takes Qingshankou granites as the research object, and uses SHRIMP zircon U-Pb method to conduct chronological analysis of the granites from Qingshankou granites. The results show that the formation ages of QSK-1 and QSK-2 are (200.5±2.9)Ma and (202.1±4.6)Ma, respectively, which confirms that the Qingshankou pluton is located in the late Indosinian-early Yanshan orogenic stage. At the same time, combining with the previous achievements, it is found that the formation of Qingshankou granite and other rocks in the EW trending tectonic belt in eastern Hebei area is mainly influenced by the main stress field in the north-south direction of North China. Moreover, Qingshankou and other NW trending granite bodies belong to the magmatic activity products of the same period and belong to the Yanshan orogenic stage.This provides a reference for the study of the evolution process of orogenic structures and the prospecting work in eastern Hebei area.