Abstract:

Based on the analyses of debris component, gravel composition, rare earth element, sandstone content distribution and glutenite distribution characteristics, and drawing on the previous research results, it can be concluded that there are six main provenance areas in the 3^rd Member of the Funing Formation, Subei Basin. The south and north sides of the Jianhu Uplift (areas Ⅰ, Ⅱ) provide sources, respectively, southward to the Eastern Jinhu, Northern Gaoyou and Hai’an Sags, with the parent rocks including mainly medium-acidic igneous rock, quartzite and granite, and northward to the Yancheng Sag, with the addition of basic igneous rock to the parent rocks from area Ⅰ. The Zhangbaling Uplift (area Ⅲ) provides source eastward to the Western Jinhu Sag, with the main parent rock types almost identical to that of area I but without granite. The Sunan Uplift (area Ⅳ) provides source northward to the Southern Gaoyou Sag, supplying mainly carbonate and medium-acidic igneous rocks as the parent rocks that are very different from the parent rocks (supplied from area Ⅰ) in the Northern Garyou Sag by the presence of large amount of carbonate rocks. According to the literature reports, the Binhai Uplift (area Ⅴ) provides source southward to the Funing Sag, with medium-deep metamorphic rocks and Paleozoic sedimentary rocks as the parent rocks; while the eastern section of the Lusu Uplift (area Ⅵ) provides sources to the Lianbei Sag, with the parent rock mainly including metamorphic acidic igneous rock of the basement. Combined with the Bhatia REE characteristic parameters and Dicknson tectonic discrimination diagrams, it is considered that the tectonic settings of the source areas are mainly active continental margins associated with continental island arc and recycled orogenic belt.

Key words: Subei Basin, 3^rd Member of Funing Formation, provenance, tectonic setting, parent-rock type, rare earth element