| 华北中寒武世张夏组复合海平面变化旋回层序 |
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| 引用本文： | 梅冥相,梅仕龙.华北中寒武世张夏组复合海平面变化旋回层序[J].沉积学报,1997,15(4):5-10. |
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| 作者姓名： | 梅冥相 梅仕龙 |
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| 作者单位： | 中国地质大学,北京 100083 |
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| 基金项目： | 国家重大基础攻关项目-中国古大陆及其边缘层序地层及海平面变化研究(SSLC)的成果之一 |
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| 摘 要： | 华北中寒武世张夏组,以发育较多的鲕粒灰岩著称。其中发育的五十至六十余个潮下型碳酸盐米级旋回层序形成有规律的垂直叠加形式,构成十余个五级旋回层序,三个四级旋回层序及一个三级旋回层序,最终形成一个典型的复合海平面变化旋回层序。这些潮下型碳酸盐米级旋回层序,常呈１∶４的叠加关系,反映了地层记录中的米兰柯维奇性质,即单个米级旋回层序与短偏心率旋回（周期为１０万年）有关。
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| 关 键 词： | 旋回层序 复合海平面变化 张夏组 中寒武世 华北 |
| 收稿时间： | 1996-07-04 |
Cyclic Sequences of Composite Sea Level change Developed in Zhangxia Formation of Middle Cambrian in North China |
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| Institution: | China University of Geosciences,Beijing,100083 |
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| Abstract: | Zhangxia Formation of the Middle Cambrian in North China is particularly famous for the well-de-veloped oolitic limestone.Many kinds of meter-scale cyclic-sequences, belonging to subtidal carbonatetype are discerned in Zhangxia Formation, and they are characteristic of "upward thickening of rock-bed" and "upward coarsening of sedimentary grain" as well as "upward shallowing of depositional enviroment".The stacking pattern of 1 ∶ 4 indicates that one meter-scale cyclic-sequence is genetically relatedto short-precession cycle of the Milankovitch cycle.In strata of Zhangxia Formation, various order cyclic-sequences and their regularly vertical stacking patterns constitute a typicall carbonate cyclic-sequence ofcomposite sea-level changes.On basis of the nature of the carbonate cyclic-sequence of composite sea-level changes developed inZhangxia Formation,it could be concluded as follows:① Cyclic-sequence ought to be a genetically relative facies-succession at first, the meaning of whichis that this facies-succession can reflect a process of relative sea-level changes.There are various ordersfor cyclic-sequences, which are genetically related to various periods of sea-level changes.② The surface of cyclic-sequence is a facies-changing surface that generally coexists with punctuatedsurface, which includes exposing punctuated surface and deepening-starve punctuated surface.③ In the research of cyclostratigraphy and sequeuce stratigraphy, especially the study of outcrop aswell as rock-core section, "lithology and lithofacies as well as facies-succession" are the key to discerncyclic-sequences, various order cyclic-sequences and their regularly vertical stacking patterns are thecore.④ Condensed section that is defined by stratigraphy, does not exist in the third-order cyclic-se-quence.In some depositional environment, there is also "condensed section" in the fourth-order cyclic-se-quence(subsequence).So it must be careful to pay attention to the belonging of coudensed section in var-ious order cyclic-sequences.⑤ There are two important factors for cyclic-sequences: regularity of facies-succession in space andsimultarity of environment change in time, both of which endow with particular meanings on stratigraphyand sedimentology to cyclic-sequences. |
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| Keywords: | ,cyclic sequence,variation of composite sea level,Zhangxia Formation,Middle Cambrian,North China, |
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