崂山大型气泡洞洞壁微形态特征及风化程度研究

发布时间：2018-08-28 09:37

【摘要】：作为中国东部A型花岗岩带的一部分,青岛崂山花岗岩岩体上不仅发育众多开口向上的天然石臼,还存在大量开口侧向的气泡洞。对于崂山天然石臼的成因,已经有人提出“冰臼说”、“风化坑说”。刘锡清等人发现了崂山花岗岩原生洞穴,即大型气泡洞和晶洞,并且提出“天然石臼与气泡洞同源说”。但是,有人认为这些洞穴是“喀斯特洞穴”,也有人怀疑是“海蚀洞”。本文经过多次对崂山地区大型气泡洞的实地考察,分别对崂山大型气泡洞洞壁、洞外及天然石臼内岩石进行取样研究,以进一步论证大型气泡洞的成因。本文从宏观(野外肉眼观察)和微观(立体镜和扫描电镜观察(SEM))两个方面研究大型气泡洞洞壁微形态特征,并且和不同动力成因(水动力、风动力和人工打磨)的岩石的表面微形态特征进行对比。结果显示大型气泡洞洞壁与其他几类岩石表面特征存在明显的区别:其一,气泡洞洞壁岩石表面较为光滑平坦,无明显的擦痕存在,石英和长石矿物颗粒高度基本一致,无高低起伏现象;其二,气泡洞洞壁岩石表面仅存在少量的裂隙,大部分矿物晶形较为完整,并且石英和长石矿物紧密相连,接触部位无裂隙存在,矿物边界明显,可明显分辨出石英和长石矿物的形态;其三,崂山大型气泡洞洞壁岩石表面蚀变程度较低,仅在石英和长石矿物边界处存在少量鳞片状集合体的绢云母。本文利用X粉晶衍射法(XRD)对大型气泡洞洞壁、洞外及灵旗峰顶石臼内岩石进行岩石矿物分析,通过分析各岩石样品的伊利石含量和英长比的不同来对比各样品的风化程度。结果显示:气泡洞洞壁岩石矿物成分中伊利石的含量远小于遭受水动力作用形成的石臼内岩石且其英长比均值数值最低,并且每个气泡洞洞壁岩石的英长比均小于洞外岩石及石臼内岩石,说明气泡洞洞壁岩石的风化程度较低,接近于新鲜岩石,并且岩石在形成过程中并未遭受外动力的侵蚀,仅在后期暴露时遭受了外力作用。同时本文还利用X射线荧光光谱法(XRF)对崂山大型气泡洞洞壁、洞外和灵旗峰顶石臼内岩石进行主量元素的分析,然后根据测量结果分别算出各样品的化学蚀变指数(CIA)、花岗岩风化指数(WIG)、科尔曼风化指数(WIC)、帕克风化指数(WIP)四种风化指数的数值,通过各风化指数数值与风化程度之间的关系对比不同类型岩石之间的风化程度以及可能遭受的外力作用,结果显示:气泡洞洞壁岩石风化程度最低,处于低等风化阶段,且洞壁无水动力作用的痕迹;气泡洞洞外岩石风化程度高于洞壁岩石,石臼内岩石风化程度最高,岩石遭受严重的水动力作用。综上所述,通过对崂山地区不同动力成因岩石的表面特征及岩石矿物化学特征的对比,表明崂山大型气泡洞洞壁岩石风化程度较低,接近于新鲜岩石,洞壁岩石遭受风化作用侵蚀的程度远远小于洞外及石臼内岩石,其风化程度属低等风化,并不是风化作用形成的洞穴,而仅仅在其暴露在空气中时遭受了微弱的风化作用;由此可见,崂山大型气泡洞在形成过程中并无外动力作用的参与,并不是“岩溶洞”和“海蚀洞”,也非风蚀洞。由此证明崂山大型气泡洞属于天然的原生洞穴。研究成果为气泡洞是花岗岩原生洞穴提供了证据。
[Abstract]:As a part of the A-type granite belt in eastern China, there are not only many natural mortars with upward opening but also a large number of lateral cavity in the Laoshan granite body in Qingdao. However, some people think that these caves are "karst caves" and others suspect that they are "sea erosion caves". In this paper, the micro-morphological characteristics of the wall of the large bubble cavity are studied from macroscopic (field observation) and microscopic (stereoscopic and scanning electron microscopic (SEM) aspects, and the surface micro-morphological characteristics of rocks with different dynamic origins (hydrodynamic, wind and artificial polishing) are also studied. The results show that there are obvious differences between the surface characteristics of the large bubble cave wall and other rock types. First, the surface of the bubble cave wall is smooth and flat, and there is no obvious scratch. The heights of quartz and feldspar mineral particles are basically the same, and there is no high and low undulation. Second, there is only a small amount of rock surface on the bubble cave wall. Most of the fissures are relatively complete, and quartz and feldspar minerals are closely linked, no fissures exist in the contact area, and the mineral boundaries are obvious, which can clearly distinguish the morphology of quartz and feldspar minerals. In this paper, the rock minerals in the wall of large bubble cave, outside the cave and in the stone mortar of Lingqi peak are analyzed by X-ray powder diffraction (XRD). The weathering degree of each rock sample is compared by analyzing the illite content and aspect ratio of each rock sample. The content of rock is much less than that of the rock in the hydrodynamic calculus and the average value of the ratio is the lowest, and the ratio of the length to the length of the rock in each cavity wall is smaller than that of the rock outside the cavity and the rock in the calculus. This indicates that the weathering degree of the rock in the cavity wall is lower, close to that of fresh rock, and the rock is not subjected to during the formation process. At the same time, X-ray fluorescence spectrometry (XRF) was used to analyze the main elements of the rock in the wall of the large bubble cave in Laoshan, outside the cave and in the stone mortar at the top of Lingqi Peak, and then the chemical alteration index (CIA) and weathering index (WEI) of granite were calculated according to the measured results. Four weathering indices, WIG, WIC and WIP, were used to compare the weathering degree between different types of rocks and the possible external forces. The results show that the weathering degree of the rocks on the wall of bubble tunnel is the lowest and is in the lower weathering stage. There is no trace of hydrodynamic action on the wall of the cave; the weathering degree of the rock outside the cave is higher than that of the cave wall; the weathering degree of the rock inside the mortar is the highest, and the rock is subjected to severe hydrodynamic action. The weathering degree of cave wall rocks is lower, close to fresh rocks. The degree of weathering erosion of cave wall rocks is much less than that of rocks outside cave and inside mortar. The weathering degree of cave wall rocks is lower than that of rocks outside cave and inside mortar. It is not a cave formed by weathering, but a weak weathering only when exposed to air. There is no external dynamic action in the forming process of the bubble cave, it is not "karst cave" or "sea cave" or "wind cave".
【学位授予单位】：山东科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P512.1

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