吉林桦甸市夹皮沟本区金矿剥露历史和矿床保存变化——来自磷灰石裂变径迹年代学证据

Denudation and Conservation History of Local District in Jiapigou Gold Deposit,Huadian County,Jilin Province——Evidence from Apitite Fission Track Thermochronology

有关吉林省桦甸市夹皮沟金矿区剥露历史的研究,至今尚不多见,然而成矿后的变化与保存是矿床学研究的一个重要领域,并且矿区剥露历史对于区内矿体保存状况具有重要的指示意义。裂变径迹是研究区域隆升剥露的一种有效手段,能提供剥蚀速率和剥蚀量的定量数据,本文应用裂变径迹技术研究夹皮沟金矿区中生代成矿以来的剥露历史。使用磷灰石裂变径迹年龄数据进行热历史模拟,揭示其演变机理。实验中获得8个了磷灰石裂变径迹测试结果,裂变径迹年龄可分为3组：（128~111Ma、86~64Ma和48~29Ma）。夹皮沟金矿区的热演化历史可分为了3个阶段,分别为：第1阶段160Ma到85±10 Ma;第2阶段85±10 Ma到28±2 Ma;第3阶段28±2 Ma至今,相应的剥露深度为2.90km、0km和1.17km。根据剥露厚度及成矿深度推测,夹皮沟本区中下戏台、立山两矿区金矿床保存状况良好,下部仍有较大探矿潜力。

The denudation history of the Jiapigou gold deposit is still unknown nowadays. Even though a large number of researches have been done in Jiapigou, the calculation of denudation in this area is relatively virgin territory. However, it is denudation that is able to significantly unveil the preservation of deposit. Fission track is able to provide the accurate thickness of denudation and uplift efficiently. This article discusses the denudation history of local district in the Jiapigou gold deposit by means of apitite fission track （AFT） technique. The thermal history has been derived from the data of AFT, 8 AFT ages have been obtained, and are divided into 3 groups of 128 -lllMa and 86 ~64Ma, as well as 48 ~29Ma. Meanwhile, three phases, such as 160 ~ （85 ±10）Ma, （85 ± 10） ~ （28±2）Ma and （28±2） -0Ma, can be received by analyzing thermal history of 6 samples. The main thickness of the section removed by denudation of each phase are 2.90kin, 0, and 1.17km respectively, which predict that the gold deposit is still lying under earthg surface by comparing with the depth of mineralization.