| 论冰川颤痕 |
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| 引用本文： | 王乃昂,刘啸,程弘毅,牛震敏,孟楠,李孟,苏贤保,杨丹.论冰川颤痕[J].冰川冻土,2022,44(4):1319-1336. |
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| 作者姓名： | 王乃昂 刘啸 程弘毅 牛震敏 孟楠 李孟 苏贤保 杨丹 |
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| 作者单位： | 兰州大学 资源环境学院/冰川与沙漠研究中心/冰川与沙漠科学观测实验站，甘肃 兰州 730000 |
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| 基金项目： | 国家自然科学基金项目(42271131) |
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| 摘 要： | 颤痕是冰川作用地区由冰川携带岩屑做周期性或间歇性运动在冰床基岩和冰碛石表面形成的新月形或弧形破裂形态，特征尺度一般不大于1 m。其主要形成机制类似Riedel构造模式中的（R）剪切破裂和（T）拉张破裂，且遵循脆性破裂原理。根据国内外文献报道和野外考察，从术语学角度将冰川颤痕分为狭义和广义两种。广义冰川颤痕，包括曲锥形擦口（狭义颤痕）、半月形裂口、新月形凿口、新月形裂纹和新月形断口5种。测量统计结果显示，23组新月形断口的排列间距，KS和JB检验均符合正态和伽玛分布（置信度95%），与岩石节理（破裂）的间距特征一致；25组新月形凿口和35组新月形裂纹的排列间距，KS检验符合正态分布和伽玛分布，JB检验不符合正态分布（置信度95%）。证明颤痕在空间分布上大体保持相等的破裂间距，基本符合饱和模式理论。颤痕的定向性、成组特征具有明确的环境意义，与擦痕、擦面的地貌组合是重要的冰川遗迹判别标志。缺少冰蚀地貌组合的孤立“颤痕”，不具有指示冰川作用的价值。近年报道的山东鲁山没有“颤痕”等冰川遗迹。
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| 关 键 词： | 颤痕 地貌分类 形成机制 判别方法 环境意义 鲁山 |
| 收稿时间： | 2022-05-13 |
| 修稿时间： | 2022-08-09 |
On glacial chatter mark |
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| Nai’ang WANG,Xiao LIU,Hongyi CHENG,Zhenmin NIU,Nan MENG,Meng LI,Xianbao SU,Dan YANG.On glacial chatter mark[J].Journal of Glaciology and Geocryology,2022,44(4):1319-1336. |
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| Authors: | Nai’ang WANG Xiao LIU Hongyi CHENG Zhenmin NIU Nan MENG Meng LI Xianbao SU Dan YANG |
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| Institution: | College of Earth and Environmental Sciences / Center for Glacier and Desert Research / Scientific Observing Station for Glacier and Desert，Lanzhou University，Lanzhou 730000，China |
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| Abstract: | Chatter mark is crescentic or arc-shaped fracture patterns formed on the bedrock or striated boulder by periodic or intermittent movement of debris carried by glaciers in glaciated area， ranging in size is generally no more than 1 m. In China， the identification markers and terminology of chatter mark are still confusing， quantitative studies are especially lacking， and a systematic disciplinary knowledge has not yet been formed. Therefore， it is necessary to explore the morphological classification， geomorphological characteristics， formation mechanism， distribution pattern， discrimination method and environmental significance of chatter mark based on relevant reports in foreign literature and measurement data obtained from fieldwork， in order to establish a conceptual system to deepen the cognitive framework of chatter mark. From the perspective of terminology， we classify the chatter mark into narrow and broad sense in this paper. The broad conception of chatter mark including five types： curved-cone crack， lunate fracture， crescentic gouge， crescentic fracture， and crescentic scar. The results of Kolmogorov-Smirnov and Jarque-Bera tests of the spacing of 23 crescentic scars are arranged in accordance with normal and gamma distribution at 95% confidence level， which is consistent with the spacing characteristics of rock joints （fractures）. The spacing of 25 crescentic gouges and 35 crescentic fractures are arranged in accordance with normal and gamma distribution by Kolmogorov-Smirnov test， but not by Jarque-Bera test at 95% confidence level. The conclusion is as follows： （1） The main formation mechanism of chatter mark analogous to （R） shear fracture and （T） tensile fracture in the Riedel Shear structure mode and follows the principle of brittle fracture. The chatter marks developed on the glacial polish surface are mainly R fracture， R′ fracture and T fracture. The forward dip of the principal fracture surface of various chatter marks is the key to reveal the mechanism of their formation. （2） Whether curved-cone crack， lunate fracture， crescentic gouge， crescentic fracture or crescentic scar is produced specifically may be related to the thickness and sliding velocity of the glacier， the concave and convex nature of the rock surface and the strength， location， shape and mode of movement （e.g.， rotation， rolling） of the rock frozen in basal ice. （3） The linear arrangement of chatter marks in groups in space， maintaining roughly equal rupture spacing， is basically consistent with the saturation mode theory. （4） The directional and group distribution characteristics of the chatter mark have definite environmental significance. The combination of chatter mark， striae and the polish is an important indicator of glacial relics. The isolated so-called “chatter mark”， without the combination of the glacial erosional landforms， is worthless in indicating glacial action. （5） The “first disclosed chatter mark” in Lushan Mountain， Shandong Province， in recent years are not “direct evidence of Quaternary glacial abrasion”， and there is no “complete evidence group”. The article “Lushan” misinterpreted the relationship between the two corners or arcs of the chatter mark and the direction of glacial movement， which led to an unrealistic misjudgment of the fracture structure of a migmatite surface affected by differential weathering in Lushan. The main peak of Lushan is only 1 108 m a.s.l. and does not have the climatic conditions for the formation of late Quaternary glaciation. |
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| Keywords: | chatter mark geomorphological classification formation mechanism distinguishing method environmental significance Lushan Mountain |
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