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在被称为“华南第一峰”的猫儿山主峰区,散落着一些具有钝形外观的花岗岩巨砾。它们是否是冰川成因?探明这一现象具有多重意义。为此,笔者从遥感、地质学和地貌学角度开展了调查研究。基于TM、Quickbird-2及TM-DEM的多尺度多模式遥感地貌学解译表明,在猫儿山主峰部位不具备形成冰川漂砾的地貌环境条件。通过成山期与冰期年代对比,虽然猫儿山成山过程经历了第四纪冰期,但不能就此断定它形成了冰川,并导致巨型漂砾形成。对主峰基岩和巨砾的矿物岩石学特征比较表明,两者为同源关系,因此巨砾并非由远处搬来,而就是来自主峰的基岩。遥感线性构造解译表明,猫儿山花岗岩体中存在五组发育的断裂构造,它们造成了花岗岩岩体的内伤,是导致巨砾形成的重要内因。而强烈的物理与化学风化作用,加上陡峭地势的斜坡重力作用,是最终导致这些巨砾形成的重要外因。我们的实地调查证实了这五方面的分析与推测。结论很清楚,猫儿山主峰区分布的花岗岩巨砾成因于断裂构造、风化剥蚀与斜坡重力三种因素的共同作用,它们只是主峰基岩的简单风化-崩塌物,而非冰川漂砾。
In the main area of Mao’er Mountain, known as the “Southern China’s First Peak,” there are scattered granite boulders with blunt appearance. Whether they are the cause of glaciers? To explore this phenomenon has multiple meanings. Therefore, the author carried out the investigation and study from the perspectives of remote sensing, geology and geomorphology. Multi-scale multi-modal remote sensing geomorphological interpretation based on TM, Quickbird-2 and TM-DEM shows that there is no geomorphic environmental conditions for the formation of glacial boulders in the main peak of Maoershan. Through the comparison between the age of Cretaceous and the age of glacial period, although the Cataresto mountain process experienced the Quaternary glacial period, it can not be concluded that it formed a glacier and led to the formation of giant boulders. A comparison of the mineralogical characteristics of bedrock and boulder on the main peak shows that the two are in a homologous relationship, so that the boulder does not come from afar but is the bedrock from the main peak. Interpretation by remote sensing linear structure shows that there are five groups of fault structures in the Maoershan granite body, which cause the internal injury of the granite rock mass and are the important internal factors leading to the formation of boulders. The strong physical and chemical weathering, together with the steep slope gravity, are the important exogenous factors that ultimately lead to the formation of these boulders. Our fieldwork confirmed these five aspects of analysis and speculation. Conclusions It is clear that the granite boulders distributed in the main peak area of Maoershan Mountain are caused by the combination of the faults, the weathering and erosion and the gravity of the slope. They are only simple weathering-collapse objects of the main peak bedrock, not glacial boulders.