山东地区新元古代土门群综合地层学分析

发布时间：2018-06-14 15:10

  本文选题：山东地区 + 新元古代地层　； 参考：《山东科技大学》2017年硕士论文

【摘要】：山东地区新元古代地层土门群的分布局限在安丘—莒县断裂及西侧附近地区,岩性基本稳定,下部和上部稍有变化。自下而上划分为黑山官组、二青山组、佟家庄组、浮来山组和石旺庄组。胶辽徐淮地区中新元古代地层研究较为薄弱,缺乏可靠的年龄控制,生物地层学存在很大的争议,化学地层学进展有限。而这其中,山东地区中新元古代地层研究相对于辽南和徐淮地区又最为不足。本文主要依据前人资料和实测剖面,通过生物地层、事件地层和年代地层等,借助多重地层划分的原理,研究山东地区土门群的归属时代。同时通过生物地层对比,事件地层对比以及碳氧同位素等方法与辽南、徐淮地区中新元古代地层进行对比研究,以便更准确的对山东地区新元古代地层的具体时代划分提供证据。研究表明:依据岩石地层、生物地层、事件地层及野外实测剖面对比研究,认为土门群上部时限有可能在720Ma,可以与辽南地区、徐淮地区新元古代地层比较分析,山东地区新元古代地层土门群可以被重新划归为青白口系。通过碳氧同位素实验并校正后主要得到如下数据:汤头剖面主要为佟家庄组、二青山组及黑山官组,其δ13C变化范围为-5.59‰—2.17‰,均值为0.79±1.01‰,整体有正漂移后又有负漂移的趋势。浮来山剖面主要为石旺庄组和浮来山组,其δ13C变化范围为-2.14‰—2.36‰,均值为1.42±0.70‰,整体经历了由正漂移后负漂移后又正漂移三个阶段。通过分析冰期碳同位素特征,土门群仅出现小幅度的碳同位素负漂移,其整体趋势基本稳定,变化幅度较小,曲线趋势明显与冰期特征及华南地区冰期前后不同,故认为其时代可能属于冰期开始之前。土门群二青山组下部有一个微小的正漂移,可与蓟县青白口系下部长龙山组处碳同位素正漂移相比较;土门群浮来山组下部出现的负漂移,可与蓟县青白口系上部井儿峪组碳同位素负漂移相比较。淮北地区碳同位素整体变化趋势为正—负—正—负—正,与土门群碳同位素整体变化趋势相同。故认为土门群可与青白口系对比。
[Abstract]:The distribution of the Neoproterozoic Tumen Group in Shandong is confined to the Anqiu-Ju County fault and the area near the western side. The lithology is basically stable and the lower and upper parts vary slightly. It is divided into Heishan formation, Erqingshan formation, Tongjiazhuang formation, Fulaishan formation and Shiwangzhuang formation from bottom to top. The study of Neoproterozoic strata in Xuhuai area of Jiaoliao is weak, lack of reliable age control, great controversy in biostratigraphy and limited progress in chemical stratigraphy. The study of MesoNeoproterozoic strata in Shandong area is the most insufficient compared with the areas of southern Liaoning and Xuhuai. Based on the previous data and measured profiles, this paper studies the time of belonging of Tumen Group in Shandong region by means of biostratigraphy, event stratigraphy and chronostratigraphy, and by means of the principle of multi-stratigraphic division. At the same time, through biostratigraphic correlation, event stratigraphic correlation and carbon-oxygen isotope correlation with the Middle and Neoproterozoic strata in southern Liaoning and Xuhuai areas, In order to provide more accurate evidence for the specific age division of Neoproterozoic strata in Shandong area. The results show that according to the comparative study of lithostratigraphy, biostratigraphy, event stratigraphy and field measured profiles, it is considered that the upper time limit of Tumen group may be 720 Ma, which can be compared with Neoproterozoic strata in southern Liaoning and Xuhuai areas. The Tumen Group of Neoproterozoic strata in Shandong area can be reclassified as Qingbaikou system. After carbon and oxygen isotope experiments, the following data are obtained: the Tangtou section is mainly composed of Tongjiazhuang formation, Erqingshan formation and Heishengguan formation, and its 未 13C varies from -5.59 鈥，

本文编号：2017815