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江汉平原是长江穿过三峡区的第一个大型卸载盆地,其沉积物必然反映长江流经的物源区的物源特征.通过对盆地中心周老孔第四纪岩心的重砂样品中0.125～0.063mm粒级的重矿物含量变化、ATi、GZi、ZTR指数和重矿物组合分析,发现从钻孔岩心深度110m开始向上,水动力条件加强,沉积速率加快,重矿物的数量特征发生明显突变,特征矿物的组合与现代长江相同.表明在周老孔岩心深度110m(古地磁年龄1.1Ma左右)位置处,长江三峡开始贯通,江汉平原开始接纳长江带来的三峡上游的物质.
The Jianghan Plain is the first large-scale unloading basin through which the Yangtze River passes through the Three Gorges area, and its sediments will inevitably reflect the source characteristics of the source region flowing through the Yangtze River. ~ 0.063mm heavy mineral content changes, ATi, GZi, ZTR index and heavy mineral assemblage analysis and found that from the core depth of 110m drilling upwards, hydrodynamic conditions strengthened, the deposition rate is accelerated, the quantitative characteristics of heavy minerals have a significant mutation , And the combination of the characteristic minerals is the same as that of the modern Yangtze River, indicating that the Three Gorges of the Yangtze River started to penetrate at a depth of 110m (about 1.1Ma in paleomagnetism) of the Zhoulao hole, and the Jianghan Plain began accepting materials from the upper reaches of the Three Gorges.