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晚古生代永安盆地位于华夏块体武夷山隆起南缘,发育在前泥盆纪基底之上,是在政和—大埔断裂带基础上经伸展作用而成的一个沉积断陷盆地。盆内不同时代含碳层位样品δ13Corg值的变化及其与邻区样品δ13Corg值的对比研究显示了盆地本身乃至整个中国东南部沉积环境在不同地质时期以及同一时期不同区段沉积相变化的异同特征;永安盆地晚古生代沉积物有机碳δ13Corg值区间主要为(-15~-25‰),与同时期金衢盆地北缘沉积物有机碳δ13Corg值区间(-20~-30‰)较为相似,盆地有机碳TOC与同时期萍乐盆地TOC也有相似之处,这些特征表明,永安盆地成盆时期的沉积环境在区域范围内与其他盆地具有相同之处,即同为海陆过渡环境;同时,又有一定的区别,浙闽沿海地区含碳层位多为中新生代,而永安盆地则为晚古生代。在晚古生代永安盆地成盆期,浙闽沿海地区为一隆起区,该隆起区和武夷山隆起区共同构成了永安盆地的主要物源区,这一认识与区域古流向调查结果基本一致。
Late Paleozoic Yongan Basin is located in the southern margin of the uplift of the Huaxia Block in Wuyi uplift, developed on the base of the former Devonian. It is a sedimentary faulted basin formed by the extension of the Zhenghe-Dapu fault zone. The δ13Corg values of carbonaceous horizon samples from different periods in the basin and its comparison with the δ13Corg value of the adjacent samples show that the sedimentary environments of the basin itself and even the whole southeastern China have similarities and differences in sedimentary facies in different geological periods and in different sections of the same period The δ13Corg value of sediments in the Late Paleozoic in Yongan Basin is mainly -15 ~ -25% o, which is similar to the δ13Corg value of sediments (-20 ~ -30% o) in the northern margin of the Jinqu Basin during the same period. The organic carbon TOC in the basin is also similar to the TOC in the Pingle Basin during the same period. These characteristics show that the depositional environment of the Yongan Basin during the basin forming period is similar to other basins in the region, namely, the transitional environment between land and sea. At the same time, There is a certain difference between the Zhejiang and Fujian coastal carbonaceous layers are mostly Mesozoic and Cenozoic, while the Yongan Basin is the late Paleozoic. In the Late Paleozoic Yongan Basin, the basin became a uplifted area in the coastal area of Zhejiang and Fujian Provinces. The uplifted area and the Wuyi uplifted area together constitute the main source area of the Yong’an Basin. This understanding is consistent with the findings of the regional paleocurrents.