Abstract Diamictites of late Ediacaran to early Cambrian age (ca. 551–518 Ma) are widespread across Southeast–Central Asia, with the Luoquan Formation particularly well preserved along the southern margin of the North China craton. A basal unconformity, comprising striations and p-forms interpreted to have been produced subglacially, was cut into Mesoproterozoic basement. Integrating new observations on the basal unconformity with the stratigraphy and sedimentology of the Luoquan Formation, an unequivocal glacial origin is demonstrated. The succession evolves from massive or stratified diamictite at the base to laminated fine-siltstone with dropstones upward, and is capped by siltstone with or without dropstones on the top. These lithological combinations represent a glacial sedimentary succession deposited recording progressive retreat of the ice margin. Based on multiple palaeoflow measurements, data from 7 new measured sections, and facies analysis, a new paleogeographic model is proposed. This model envisages the expansion of a large continental ice sheet from north to south at the southern flank of the North China Craton (NCC).

中文翻译：

---

豫西埃迪卡拉纪-寒武纪冰盖形成的冰下床形态与景观

摘要 埃迪卡拉纪晚期至寒武纪早期（约551-518 Ma）的混叠岩广泛分布于东南亚—中亚，其中华北克拉通南缘的罗泉组保存最为完好。包含条纹和 p 型的基底不整合被解释为在冰下产生，被切入中元古代基底。将关于基底不整合面的新观测与罗泉组的地层学和沉积学相结合，证明了明确的冰川起源。层序由基部块状或层状混叠岩演化为层状细粉砂岩，向上有滴石，顶部为粉砂岩，有或无滴石。这些岩性组合代表了记录冰缘逐渐退缩的冰川沉积序列。基于多次古流测量、7个新测量剖面的数据和相分析，提出了一种新的古地理模型。该模型设想了在华北克拉通 (NCC) 南翼从北向南扩张的大型大陆冰盖。