安徽铜陵地区早、晚石炭世地层之间砾岩的发现

DISCOVERY OF PETROMICTIC CONGLOMERATE BETWEEN EARLY AND LATE CARBONIFEROUS STRATA IN THE TONGLING AREA,ANHUI PROVINCE

通过一系列地层剖面的测制,在铜陵、南陵、泾县地区早、晚石炭世地层之间发现了沉积石英质砾岩和岩屑砾岩,肯定了本区在早、晚石炭世之间曾经历一次海平面下降和风化剥蚀作用,致使早石炭世地层在许多地方残缺不全,由于石英质砾岩与岩屑砾岩在岩性、沉积特征、成因等方面有明显的不同,分别称为浙溪组下段和浙溪组上段。早期的石英质砾岩由于受到后期的冲积扇沉积环境的影响,在一些剖面上表现为缺失。岩屑砾岩的沉积厚度、砾石大小等在纵、横向上变化较大,明显受古地理、古气候、古构造的控制。

The quartzose conglomerate and lithic conglomerate occur between Early and I.ate Carboniferous strata at muhiple sections in the Tongling, Nanling. and Jingxian regions, indicating a sea level drop, erosion, and weathering in these regions that led to stratigraphic incompleteness in the Early Carboniferous. The lithostratigraphic difference between quartzose conglomerate and lithic conglomerate allows a differen- tiation between the upper and lower Zhexi Formation. Quartzose conglomerate of the lower Zhexi Forma lion can be incomplete at some sections because of erosion during later fluvial fan development. Stratigraphic thickness and clast size varies in both vertical and horizontal directions, and this variation was controlled by paleogeographic, paleoclimatic and tectonic factors.