| 塔中古溶洞见证晚奥陶世抬升幅度 |
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| 引用本文： | 申银民,李越,赵乐元,刘永福,孙玉善,李猛.塔中古溶洞见证晚奥陶世抬升幅度[J].地质科学,2010,45(2):349-360. |
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| 作者姓名： | 申银民 李越 赵乐元 刘永福 孙玉善 李猛 |
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| 作者单位： | 1.北京大学地球空间学院北京 ,100871； ,2.中国科学院南京地质古生物研究所南京 ,210008； ;
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3.中石油塔里木油田分公司勘探开发研究院新疆库尔勒 ,841000 |
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| 基金项目： | 中国科学院创新工程方向性项目，国家自然科学基金，科技部科研项目 |
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| 摘 要： | 塔中隆起区上奥陶统良里塔格组灰岩与桑塔木组砂—粉砂岩之间为不整合接触,昭示着这两个组沉积期之间存在一次历时约百万年的区域性构造抬升事件。中古31井良里塔格组三段的4 125.6～4 133.9 m井段为垮塌型溶洞沉积,洞顶距良里塔格组二段顶部190.6 m,溶洞中角砾状充填物主要来自良里塔格组洞壁本身的礁相灰岩,且见数厘米厚的暗河流水沉积纹层,未发现源于其它时代的颗粒混杂其间。这一事实指证了溶洞的形成和充填时代均为良里塔格组沉积之后、桑塔木组覆盖之前的晚奥陶世凯迪中期。具溶蚀力的淡水潜流带的深度一般不低于周围的海平面,由此可推断出该井区这次抬升出海平面之上的高度,即使忽略良里塔格组顶部可能经地表剥蚀的良里塔格组一段,抬升出水面部分至少也应该有190 m,藉生态地层学恢复洞壁礁灰岩沉积时的海水深度约为30 m±,因此总抬升幅度至少能达到220 m。
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| 关 键 词： | 古溶洞 抬升幅度 晚奥陶世 良里塔格组 中古31井 塔中 |
| 收稿时间： | 2009-01-16 |
| 修稿时间： | 2009-03-18 |
Paleocave as a proxy for calculating uplift amplitude of the Late Ordovician in central Tarim, Xinjiang, northwest China |
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| Shen Yinmin,Li Yue,Zhao Leyuan,Liu Yongfu,Sun Yushan,Li Meng.Paleocave as a proxy for calculating uplift amplitude of the Late Ordovician in central Tarim, Xinjiang, northwest China[J].Chinese Journal of Geology,2010,45(2):349-360. |
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| Authors: | Shen Yinmin Li Yue Zhao Leyuan Liu Yongfu Sun Yushan Li Meng |
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| Institution: | 1.Earth and Space Sciences|Peking University|Beijing |100871； |2.Nanjing Institute of Geology and Palaeontology|Chinese Academy of Sciences|Nanjing |210008； |3.Exploration and Development Research Institute|Tarim Oilfield Company|Korla|Xinjiang |841000 |
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| Abstract: | Unconformably contact between the sandstone-siltstone of the Sangtamu Formation and limestone of the Lianglitag Formation in Ordovician,Kaitian,exists in the Tazhong High,central Tarim Platform. It distinctively indicates a regional tectonic uplift event happened with duration of about 1 Ma. A suite of coalesced,collapsed-paleocave sediment occurred from the 4 125.6～4 133.9 m drilling core of the well Zhonggu 31 is assigned to the Member 3 of the Lianglitag Formation. The depth between the cave-ceiling and the top of the Lianglitag Formation is about 190 m. The sediment-fill facies mainly consist of chaotic breccias sourced from the cave-wall,which the latter had been reefal rocks originally. Centimeters thick of laminated silciclastic debris implicates hidden river facies. Sediment of no-Kaitian time has not been found. Such a case implies that the formed and filled-processions of the paleocave was consistent to the time-interval between the post-Lianglitag Formation and pre-Sangtamu Formation timely. The depth of the vadose with dissolutional excavation was generally not lower than its surrounding sea-level. Even though the un-remained thickness of the Member 1 of the Lianglitag Formation,which had been eroded by karstfication of the earth surface in advance of a new cycle transgression of the Sangtamu Formation could be negative,the exposed part of the Lianglitag Formation above the sea-level was minimal of 190 m at least. Reefal rocks of the cave-wall were formed at a depth about 30 m of the sea-floor. Thus,the sum of the exposed high plus the reef community depth results the amplitude of the uplift. |
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| Keywords: | Paleocave Amplitude of the uplift Late Ordovician Lianglitag Formation Well Zhonggu 31 Central Tarim |
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