近年来随着对前寒武纪研究的进一步开展，中晚元古代地层的一种被称为“臼齿碳酸盐岩［Molar Tooth(简称MT)Carbonate s］”或“微亮晶碳酸盐岩”或“臼齿构造(Molar Tooth Structure，简称MTS)”的沉积现 象受到了国际地学界的重视。臼齿碳酸盐岩特指由微亮晶方解石组成、具肠状褶皱席(Ptygm atically folded sheets)构造的元古代碳酸盐岩。臼齿碳酸盐岩在地质历史中扮演着重要 的角色，其似乎成了早元古代火山喷发热水沉淀碳酸盐与显生宙带壳化石碳酸盐沉积之间的 桥梁，更重要的是在地球生命演化中起着重要的作用。利用现代测试手段和方法对吉辽地区 新元古代含臼齿碳酸盐岩地层剖面砂岩的氧化物含量、稀土元素和臼齿碳酸盐岩的碳同 位素、氧同位素、锶同位素、生物标志物、能谱进行了分析，从地球化学角度揭示了臼齿碳 酸盐岩形成的构造背景、古温度场、形成时限、物质组分和沉积环境特征等，从而印证了沉 积学研究成果：吉辽地区的臼齿碳酸盐岩主要发育在新元古代地层中，大约在750～900 Ma 左右；MT形成于华北地台稳定构造背景之下低纬度、古水温一般在50℃左右的热带气候条件 下的内缓坡环境中；MT由微亮晶方解石和基质两部分组成。

Along with the research progress on Precambrian, the Molar  tooth carbonates (briefly called MT, or called microsparite carbonates or MT st ructure) being formed in mid-late Proterozoic become a target of crossing firer ecently. The Proterozoic Molar-tooth (MT) carbonate rocks refer to those Meso- to Neoproterozoic (1 700～650 Ma) carbonates with MT structure, being a series o f pecular, ptygmatically folded and spar-filled cracks in fine-grained carbona tes of Precambrian age, located in the environment of mid-to inner ramp and sha llow platform. Like a bridge, MTS connected the inorganic world with the organic  one and is closely related to the evolution of the paleo-oceans, the atmospher e and the biosphere. Their development and/or recession are related to the origi n of life and the abruption of sedimentary geochemistry of marine carbonates. By  using of morden instruments and testing methods adequately in this paper, cont ents of sandstone oxides and the model curve of REE distribution were measured;  the ⁸⁷Sr/⁸⁶Sr isotopic ratio obtained an accurate value, tha t is, the age of MT formation is about 750～900 Ma; C and O isotopes of some fre sh micrite limestone samples were analyzed; the energy spectrum analysis found t hat MT consists of microspar calcite mainly, while chemical composition of the m atrix is abundantly of peaks Ca, M, Al, Si, K.The geochemical indicators proved  that the MT carbonates of Neoproterozoic in the Ji-Liao region developed in the  margin of the stable continent, formed in the torrid zone and the paleo-temper atures were about 50℃, the sea water was normal salinity when MT formed during  the wanlong period in the southern Jilin, the Yingchengzi period and the Xingmin cun period in the eastern Liaoning. the sedimentary environment located in the i nner ramp. In summary, it is of important significance for the origin of the MT,  also for the paleo-climate, the paleo-environment, ascertaining the age and t he stratigraphy division and correlation of the Proterozoic to study the geochem ical features of the MT carbonates and its formation environment.