滇西南石炭纪平掌组火山岩与鱼塘寨组的接触关系

On the Contact Between the Carboniferous Yutangzhai Formation and the Underlying Pingzhang Formation in Southwest Yunnan

在永德县班卡安信槽村和澜沧县老厂等地发现几条出露良好的界线剖面，清楚地揭示了鱼塘寨组和下伏平掌组火山岩之间的沉积接触关系，并可分为３种不同的接触类型，这对于阐明昌宁—孟连带的地质演变历史具有重要意义。

There has been a debate about the contact between the Pingzhang Formation and the Yutangzhai Formation of the Late Carboniferous because nowhere the contact surface can be definitely seen. Prof.Wu Genyao(1991, 1993; Wu et al. , 1995) argued in favour of the faulted contact instead of conformable contact between them. In 1997, we found several sections with excellent exposures of the contact in Anxincao of Yongde County and Laochang of Lancang County(pl.Ⅰ,figs.1,2). Thus we come to the necessary conclusion that the sedimentary contact between the two Formations is only too true. The model of the Indosinia interdigitational texture(Wu, 1991,1993;Wu et al. , 1995) did not hold water because the two Formations belong to the same stratigraphical system.