Subglacial bedforms and landscapes formed by an ice sheet of Ediacaran-Cambrian age in west Henan, North China
Subglacial bedforms and landscapes formed by an ice sheet of Ediacaran-Cambrian age in west Henan, North China
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DOI：
10.1016/j.precamres.2020.105727
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发表时间：
2020-07
影响因子：
3.8
通讯作者：
Xiaoshuai Chen;H. Kuang;Yongqing Liu;Yuchong Wang;Zhenrui Yang;T. Vandyk;Daniel Paul Le Heron;Shiyan Wang;Y. Geng;H. Bai;Nan Peng;Xiaoxu Xia
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文献类型：
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作者：
Xiaoshuai Chen;H. Kuang;Yongqing Liu;Yuchong Wang;Zhenrui Yang;T. Vandyk;Daniel Paul Le Heron;Shiyan Wang;Y. Geng;H. Bai;Nan Peng;Xiaoxu Xia
埃迪卡拉纪晚期至寒武纪早期的杂岩（约。551-518 Ma）广泛分布于亚洲东南部-中亚地区，其中华北克拉通南缘的罗泉组保存得尤为完好，分布于沿着。基底不整合，包括条纹和p型解释已产生亚冰川，被切割成中元古代基底。将底部不整合的新观察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。层序由底部的块状或层状混杂岩演化为向上有坠石的层状细粉砂岩，顶部为含或不含坠石的粉砂岩盖层。这些岩性组合代表了冰川沉积序列，记录了冰缘的不断后退。在多次古水流测量的基础上，结合7条新测剖面的资料，结合相分析，提出了新的古地理模式。该模式设想了在华北冰盖南翼由北向南扩展的大型大陆冰盖。
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).