【作者】 汤圆圆；

【导师】 梅冥相；

【作者基本信息】 中国地质大学（北京） ， 矿物学、岩石学、矿床学， 2010， 硕士

【摘要】 燕山地区是中国北方中—上元古界地层最为发育的地区,整个地区露头连续、地层齐全、沉积稳定。其中天津蓟县剖面地层发育最为完全,厚度巨大,是研究中—上元古界沉积的典型剖面。燕山地区中元古界以盐酸盐岩占优势,间有碎屑岩和粘土岩,为潮间带至潮下带沉积,属滨海沙滩相、潮坪相及水下陆棚相。南口群包括高于庄组和杨庄组,其中高于庄组是一套碳酸盐岩占绝对优势的地层。其特点是下部含叠层石较丰富,中部普遍含锰较多,上部含各种形态的结核。与大红峪组为平行不整合接触。根据沉积组构特征,可划分为四个二级层序:第一个二级层序S5对应高于庄组一段(官地亚组),岩性特征为:底部为一套1～3米后的石英砂岩,向上为潮间带至潮上带含陆屑的叠层石白云岩、泥质白云岩,夹白云质砂岩、白云质粉砂岩。可进一步划分为6个三级层序(S.5.1—S.5.6);高于庄组二段(桑村鞍亚组)构成第二个二级层序(S6),其岩性特征为:下部为潮上带至潮间带含锰白云岩和含锰白云质粉砂质白云岩;上部为潮下带泥晶白云岩。S6可识别出S.6.1和S.6.2两个三级层序。第三个二级层序与高于庄组三段(张家峪亚组)对应,岩性特征为:潮下带至陆棚相白云质灰岩和泥质白云岩,纹理发育,纹理中富含有机质页片,不发育叠层石,但发育特殊的MT构造。根据旋回特征可划分为3个三级层序(S.7.1—S.7.3)。高于庄组四段(环秀寺亚组)构成第四个二级层序,岩性以潮坪相块状叠层石白云岩岩礁为特征,进一步划分为两个三级层序(S.8.1、S.8.2)。杨庄组本身构成一个二级层序S9,该二级层序是南口群第五个二级层序,以夹白云岩层的灰紫色及紫红色白云质泥页岩为特征,特殊的颜色和岩性表明为局限泻湖相沉积。根据潮坪相叠层石白云岩到泻湖相紫红色泥页岩的序列特征可划分为4个三级层序(S.9.1—S.9.4)。研究区地层自蓟县向东、南尖灭变薄,在兴隆、宽城、迁西剖面地层厚度明显变薄,由蓟县剖面的2100余米变为1000余米,在青龙、滦县剖面已变为几百米,到抚宁则完全尖灭。更多还原

【Abstract】 The Yanshan area is the most developed region of the Meso- and Neoproterozoic stratum in north China, the whole area has continuous outcrops, complete stratum and steady deposition. The Jixian section, Tianjin, is the ideal section to study Meso- and Neoproterozoic deposition because it has the most complete strata and the stratum thickness are gigantic. The Neoproterozoic stratum in Jixian section is dominated by carbonate mixed with clastic rock and clay rock which belongs to lithoral facies, tidal-flat facies and submarine shelf facies. The Nankou Group includes Gaoyuhzuang Formation and Yangzhuang Formation. The Gaoyuzhuang Formation is dominated by carbonate and the contact relationship between Dahongyu Formation is parallel unconformity. The lower part of Gaoyuzhuan Formation is characterized by various stromatolite; the middle part include a great number of manganese; the upper part is marker by various nodules. The Nankou Group can be divided in to four second-order sequences according to their fabric features of facies succession:The first second-order sequence of Nankou group (S5) consistent with the first member of Gaoyuzhuan Formation (or the Guandi subformation), it’s lithologic character is variational: the lower part is a set of quartz sandstone, the thickness is 1~3 meters; the upper are mainly intertidal zone or supratidal zone deposits, which include stromatolitic dolomite with terrestrial clastics or argillaceous dolomite with dolomitic sandstone or dolomitic siltstone interbeded. And futher, the S5 can be divided into 6 third-order sequences (S.5.1-S.5.6). The second member of Gaoyuzhuang Formation (or the Sangshu’an subformation) consistent with the second second-order sequence of Gaoyuzhuang Formation (S7), the lithologic character of the lower part is intertidal zone or supratidal zone manganous dolomite and manganous dolomitic silty dolomite; the upper part is subtidal zone dolomicrite. S6 can be divided into tow third-order sequence S.6.1 and S.6.2. The third second-order sequence (S7) consistent with the third member of Gaoyuzhuang Formation (or the Zhangjiayu subformation), the lithologic character is subtidal zone to shelf facies dolomitic limestone and argillaceous dolomite. There are organic clastic in texture; have no stromatolitic but develop particular molar tooth (MT). The third second-order sequence can be divided into 3 third-order sequence (S.7.1-S.7.3) according to cycle character. The forth member of Gaoyuzhuang Formation (or the Huanxiusi subformation) consist the forth second-order sequence (S8), which dominated by tidal-flat facies mass stromatolitic dolomite, the S8 can be divided into 2 third-order sequence (S.8.1-S.8.2) further. The Yangzhuang Formation itself consist a second-order sequence (S9), it is also the fifth second-order sequence of Nankou Group. The Yangzhuang Formation is dominated by interbedding dolomite and dusty purple-purple dolomitic mudstone, the particular color and lithology indicate confining lagoon facies deposits. According to the cycle feature, the Yangzhuang Formation can be divided into 4 third-order sequence (S.9.1-S.9.4). In the study area, the strata becomes thinner from Jixian section to east and south, the strata thickness at Jixian section is more than 2100 meters but only approximately 1000 meters at Xinglong section, Kuancheng section and Qianxi section. At Qinglong section and Luanxian section, the thickness is several hundreds meters and eventually pinch at Funing section.更多还原