| 华北地台寒武纪沉积层序中关键地层单元──海绿石质凝缩层段 |
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| 引用本文： | 陈荣坤.华北地台寒武纪沉积层序中关键地层单元──海绿石质凝缩层段[J].沉积与特提斯地质,1994(6). |
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| 作者姓名： | 陈荣坤 |
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| 作者单位： | 国家建筑材料工业局地质研究所 |
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| 摘 要： | 构成华北古克拉通盆地的中晚寒武世碳酸盐沉积层序及与三级海平面最大海泛期相关的海绿石质凝缩层段是一沉积速率极低、厚度较薄的海相沉积单元。笔者根据凝缩层段中海绿石矿物的Ｋ２Ｏ百分含量和其内部晶体结构划分出其演化级次和形成时限，得出研究区凝缩层段的形成时限为１０４－１０６年。它们与二级、三级海平面最大海泛滞后期相吻合。该成果对区域地层对比、层序划分、海平面升降史和盆地充填史的恢复起极为重要的作用。
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| 关 键 词： | 海绿石，凝缩层段，三级海平面升降，最大海泛滞后期 |
KEY STRATIGRAPHIC UNITS-GLAUCONITIC CONDENSED SECTIONS IN THE CAMBRIAN DEPOSITIONAL SEQUENCES ON THE NORTH CHINA PLATFORM |
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| Chen Rongkun.KEY STRATIGRAPHIC UNITS-GLAUCONITIC CONDENSED SECTIONS IN THE CAMBRIAN DEPOSITIONAL SEQUENCES ON THE NORTH CHINA PLATFORM[J].Sedimentary Geology and Tethyan Geology,1994(6). |
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| Authors: | Chen Rongkun |
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| Abstract: | The Middle to Late Cambrian carbonate strata on the North China Platform are composed of seven third-order cyclic sequqnces. Glauconitic condensed sections (CS) which are recognized in individual sequences and related with the maximum flooding lag stage are a kind of marine depositional units with relatively thin thickness and low depositional rates.The evulutionary stages and time durations of the condensed sections have been distinguished in the light of percentage contents of K2O and internal crystal textures of glauconite. It is estimated that the time durations of the condensed sections range between 104 and 106 years which coincide with the maximum flooding lag stage of the second-order or third-order sea-level fluctuations. This conclusion has important implications for the regional stratigraphic correlation,sequence division,and the reconstruction of sea-level fluctuations and basin fill history. |
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| Keywords: | glauconite condensed section the third-order sea-level fluctuation the maximum flooding lag stage |
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