内蒙古鄂托克早白垩世恐龙足迹化石8号点风化机理研究  

Study on weathering mechanism of dinosaur tracks from Early Cretaceous in tracksite No.8,Otog,Inner Mongolia

作　　者：韩向娜 赵文华 李辰元 华格格根 张笠夫 王丽霞 李阳 汪筱林[4,5,6] HAN Xiang-na;ZHAO Wen-hua;LI Chen-yuan;HUA GE GE Gen;ZHANG Li-fu;WANG Li-xia;Li Yang;WANG Xiao-lin(Institute for Cultural Heritage and History of Science and Technology,University of Science and Technology Beijing,Beijing 100083,China;Administration of the Otog DinosaurTrace Fossil Nature Reserve,Ordos 016100,Inner Mongolia,China;Ordos Forestry and Grassland Career Development Center,Ordos 017010,Inner Mongolia,China;Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences,Institute of Vertebrate Paleontology and Paleoanthropology,Chinese Academy of Sciences,Beijing 100044,China;CAS Center for Excellence in Life and Paleoenvironment,Beijing 100044,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]北京科技大学科技史与文化遗产研究院,北京100083 [2]内蒙古鄂托克恐龙遗迹化石自然保护区管理局,内蒙古鄂尔多斯016100 [3]鄂尔多斯市林业和草原事业发展中心,内蒙古鄂尔多斯017010 [4]中国科学院古脊椎动物与古人类研究所,脊椎动物演化与人类起源重点实验室,北京100044 [5]中国科学院生物演化与环境卓越创新中心,北京100044 [6]中国科学院大学,地球与行星科学学院,北京100049

出　　处：《古生物学报》2022年第1期151-164,共14页Acta Palaeontologica Sinica

基　　金：国家自然科学基金(41688103,41572020);中央高校基本科研鄂托克地方合作项目(FRF-MP-20-53)联合资助。

摘　　要：内蒙古鄂托克旗查布地区是罕见的恐龙足迹等遗迹化石分布区,分布着大量白垩纪恐龙足迹化石。这些足迹化石在野外遭受着不同程度的风化破坏,为此在足迹密集的核心区8号点建立了野外地质遗迹博物馆保护原址。跟踪观察后发现室内足迹化石的风化程度相较于露天保存更加严重,尤其在馆内靠近四周围墙的区域,足痕表面酥粉破碎,有的足迹甚至完全消失。为研究8号点足迹化石的风化原因,本文对8号点馆内外赋存于同一层位的岩石进行取样,使用偏光显微镜(PM)、X射线衍射(XRD)、压汞(MIP)、离子色谱(IC)、拉曼光谱(Raman)、傅里叶变换红外光谱(FTIR)以及扫描电子显微镜能谱(SEM-EDS)等方法进行分析,结果发现室内岩石的孔隙率更高,孔径更大,可溶盐含量是室外上层的2倍,室外下层的约11倍,种类以NaCl和Na;SO;为主。模拟实验显示,相比冻融作用,Na;SO;更具有破坏性。由此认为导致鄂托克遗迹博物馆内恐龙足迹化石风化的机理是由地下水和降雨形成的地表水共同作用的结果,尤以Na;SO;为主的可溶盐产生强烈的水盐活动。同时,之前用作加固的硝基清漆保护效果不明显,并尝试提出保护性建议。Chabu area in Otog Qi, Inner Mongolia, is a rare fossil producing area of dinosaur footprints in the world, which is rich of dinosaur tracks from Early Cretaceous. However, these footprint fossils are experiencing different degrees of weathering in the field. In order to protect these fossils in-situ, the Otog Field Museum of Geological Vestige was built on the Tracksite No. 8. Whereas, it was found that the weathering degree of indoor footprints was more serious than that in the field, especially the area within the museum near the surrounding walls,and the surface of the footprints gradually became efflorescence and broken, and some even completely disappeared.In order to understand this weathering phenomenon, fossil rocks of the same stratum inside and outside the museum were tested by means of polarized light microscope(PM) observation, X-ray diffraction(XRD) analysis, mercury intrusion test(MIP), ion chromatography(IC) analysis, Raman spectroscopy(Raman) analysis, Fourier transform infrared spectroscopy(FTIR) analysis and scanning electron microscopy(SEM-EDS) analysis in this article. It is found that the indoor rock has a higher porosity and larger pore size, and soluble salts content is 2 times that of the surface rock as well as 11 times of subsurface rock. The soluble salts are mainly NaCl and Na;SO;. Though simulated aging tests, it is found that the damage of soluble salt is greater than freeze-thaw, and Na;SO;is the most damage salt. Therefore, it is indicated that the weathering mechanism of dinosaur tracks in the museum is the combined action of groundwater and surface water formed by rainfall, which leads to strong water-salt activity of Na;SO;. It is found that the nitrocellulose varnish, which was used as consolidant and sealing material, did not have a good protective effect. Some suggestions are put forward to deal with this problem.

关 键 词：恐龙足迹 风化机理 可溶盐 冻融作用 早白垩世 鄂托克 

分 类 号：Q915.2[天文地球—古生物学与地层学]