天津矿产资源特征及其成矿规律

天津虽不是资源大省,但矿产资源种类较多,成矿类型较为复杂。本文总结了天津市辖区内矿产资源的分布特征,并系统总结了矿产资源的时空演化规律:时间上,成矿作用发育持续时间长,按构造演化时段,可分为太古宙、元古宙、古生代、中生代、新生代5个时段,以元古宙为主要成矿期;空间上,可以划分为2个Ⅲ级、4个Ⅳ级构造单元,金属和非金属矿产资源主要分布在北部Ⅳ级构造单元的蓟唐裂谷中,油气、地热、地下水等矿产主要分布在南部黄骅坳陷区。根据矿产时空分布规律和地质构造环境,将天津全域划分为2个Ⅲ级成矿带,6个Ⅳ级成矿亚带,并厘定出11个矿床成矿系列22个亚系列,建立了区域成矿谱系,探讨总结了不同成矿作用、成矿单元与成矿系列的演化趋势,认为沉积作用是天津最主要的成矿作用,形成的成矿系列呈现出由中元古代金属、非金属→晚古生代、中生代能源矿产煤→新生代能源矿产石油、天然气的演化趋势;矿床成矿系列随着时间演化,在晚期不同成矿单元内均呈现多样化特征。

Characteristics and metallogenic regularity of mineral resources in Tianjin

Despite its small size Tianjin hosts a variety of mineral resources and complex metallogenic deposits.This paper summarizes the distribution characteristics and spatial-temporal evolution regularity of mineral resources discovered in this region.The metallogenic processes extending over a prolonged geological time interval can be divided into five periods i.e.Archean,Proterozoic,Paleozoic,Mesozoic and Cenozoic.The Proterozoic is the main metallogenic period in Tianjin.Tianjin can be divided into 2Ⅲ-level and 4Ⅳ-level tectonic units.Metallic and non-metallic mineral resources are mainly distributed in the Jitang rift valley in the northernⅣ-level tectonic units of Tianjin,while the oil and gas,geothermal minerals and groundwater are mainly located within the Huanghua depression in southern Tianjin.Based on the spatial and temporal distribution of mineral resources and their tectonic setting,Tianjin can be divided into 2Ⅲ-level and 6Ⅳ-level metallogenic belts.On this basis,11 metallogenic series and 22 subseries are identified,regional metallogenic lineages are established,and the evolutionary trends of different mineralization,metallogenic units and metallogenic series are discussed and summarized.It is believed that sedimentation is the most important mineralization process in Tianjin.The metallogenic series shows the evolutionary trend from Mesoproterozoic metals and non-metals to late Paleozoic-Mesozoic coal,and finally to Cenozoic oil and natural gas.Over time the metallogenic series have developed diversified characteristics in different metallogenic units.