Keywords: 
• non-stromatolitic carbonate succession /
• Gaoyuzhuang Formation /
• Mesoproterozoic /
• Qiangou section in Yanqing

Abstract: In the long Precambrian, the stromatolitic carbonate succession is very common. But, the nonstromatolitic carbonate succession that is marked by the subtidal deposits forms a strong contrast to the stromatolitic carbonate succession. Both the nonstromatolitic and the stromatolitic carbonate successions are important clues for the further understanding of the evolving carbonate world of the Precambrian. The Mesoproterozoic Gaoyuzhuang Fm. in Yanshan Area is a set of more than 1000mthick carbonate strata that can be divided into four Members (or Subformations): The first Member (or the Guandi Subformation) is marked by a set of stromatolitic dolomites overlying a set of transgressive sandstones; The second Member (or the Sangshuan Subformation) is a set of manganiferous dolomites with a few stromatolites; The third Member is chiefly made up of limestones and is characterized by a particularly nonstromatolitic carbonate succession of the Precambrian; The fourth Member (or the Huanxiusi Subformation) is composed of a set of dolomites of stromatolitic reefs or lithoherms. The nonstromatolitic carbonate succession making up the third Member of the Gaoyuzhuang Formation at the Qiangou section in Yanqing County of Beijing can further be subdivided into three thirdorder sequences that are marked by the regular succession of sedimentary facies. In thirdorder sequences, lots of subtidal carbonate meterscale cycles made up of the midiumbedded leiolite limestones and the thinbedded marls constitute their transgressive system tracts (TSTs) and the early highstand system tracts (EHSTs), lots of meterscale cycles made up by the thinbedded limestones and marls constitute their condensed sections (CSs), and thickbedded to massive dolimitic limestones or lime dolomites make up the late highstand system tracts (LHSTs). The time scan of the Gaoyuzhuang Formation is deduced as 200 Ma (from 1600 Ma to 1400 Ma). An obvious hiatus between the Gaoyuzhuang Formation and the underlying Dahongyu Formation is deduced as 50 Ma to 100 Ma, so the forming duration of the Gaoyuzhuang Formation is thought as the 100 Ma (1 500 Ma to 1 400 Ma). Furthermore, the subface of the third Member of the Gaoyuzhuang Formation that is just on the mid position of the Gaoyuzhuang Formation and its forming age may be deduced as about 1 450 Ma. According to these materials, the nonstromatolitic sedimentary succession make up the third Member of the Gaoyuzhuang Formation may demonstrates a stromatolite decline event occurring at ca. 1 450 Ma of the Proterozoic besides other three events that respectively occurred at ca. 2 000 Ma, ca. 1 000 Ma and ca. 675 Ma. The forming duration of this nonstromatolitic sedimentary succession of the third Member of the Gaoyuzhuang Formation can be generally correlative that of a similar sedimentary succession in North America, i.e. a nonstromatolitic sedimentary succession of the Helena Formation of the Belt Supergroup, which suggests that the stromatolite decline occurring at ca. 1 450 Ma is a global event. All of these information’s endow the nonstromatolitic sedimentary succession making up the third Member of the Gaoyuzhuang Formation at the Qiangou section with important significance. The particularly nonstromatolitic carbonate succession make up the third Member of the Mesoproterozoic Gaoyuzhuang Formation at the Qiangou section might be the representative of the nonstromatolitic carbonate succession of the Precambrian because of its special lithological features and particular sedimentary structures, whose general sedimentary features are helpful and meaningful for the further understanding of changing regularities of the sophisticate and evolving carbonate world of the Precambrian.