四川西北部的岩关阶

<正> 四川西北部早石炭世地层,前人作过不少研究,侯德封、杨敬之(1939)在北川、绵竹、平武及江油一带进行地质调查,将下石炭统划分为杜内阶及维宪阶。朱森等人(1939)将下石炭统命为总长沟系,分上、下两部分,分别代表维宪阶及杜内阶。范影年(1980)依据珊瑚类化石,将原总长沟系的下部划分为两部分,下部称长滩子段,上部称马角坝段,并将

The Aikuanian Stage of northwestern Sichuan

Based on the contained stromatoporoids, rugose corals, brachiopods as well as the sedimentary facies, the Aikuanian sequences are subdiyided ascendingly into three formations, namely, the Beichuan Formation, the Changtanzi Formation and the Majiaoba Formation. All of them are dominantly composed of neritic carbonate rocks, totalling 27—587m in thickness. The Devonian rocks are continuous with the Carboniferous ones. The Devonian-Carboniferous boundary may be drawn at the boundary between the Upper Devonian Maoba Formation and Lower Carboniferous Beichuan Formation, corresponding to the boundary between the Famennian and the Etroeungtian in W. Europe.