| 鄂尔多斯盆地南缘奥陶系平凉组深水沉积特征及其与古环境关系--以陕西富平赵老峪地区为例 |
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| 引用本文： | 李华,何幼斌,黄伟,刘朱睿鸷,张锦.鄂尔多斯盆地南缘奥陶系平凉组深水沉积特征及其与古环境关系--以陕西富平赵老峪地区为例[J].沉积学报,2018,36(3):483-499. |
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| 作者姓名： | 李华 何幼斌 黄伟 刘朱睿鸷 张锦 |
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| 作者单位： | 1.长江大学地球科学学院, 武汉 430100; |
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| 基金项目： | 国家自然科学基金项目(41472096;41502101)，湖北省创新群体基金(2015CFA024)，长江青年基金(2015cqn26) National Natural Science Foundation of China |
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| 摘 要： | 深水沉积及其与古地理的关系一直是沉积学领域研究的重点，也是薄弱环节之一。鄂尔多斯盆地南部富平赵老峪地区奥陶系平凉组深水沉积发育，岩性以泥晶灰岩及砾屑灰岩为主，局部可见泥灰岩、泥岩、硅岩及凝灰岩。沉积构造以流水波痕和小型交错层理为主，生物扰动极为发育。典型岩相有泥晶石灰岩夹硅岩和泥岩相、生物扰动泥晶灰岩相及块状层理灰岩相，分别代表斜坡原地沉积、等深流沉积及碎屑流沉积。三种沉积的δ13C-δ18O、Th-U、Ga-Cu、B-Cr、B-Ga、B-Sr、Ni/Co-U/Th、B/Ga-U/Th及87Sr/86Sr-Sr/Ba等地化指标差异明显。从下至上，斜坡原地沉积及碎屑流沉积规模逐渐减小，等深流沉积规模不断增加。另外，平凉组沉积时期，相对海平面整体上升，古盐度呈多个高-低旋回变化，古气候逐渐干燥，还原作用增强。其中，相对海平面升高，古盐度变化明显，湿润气候及较强还原作用有利于等深流沉积的发育；而相对海平面降低、干燥气候及构造运动有利于碎屑流沉积发育。
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| 关 键 词： | 等深流 碎屑流 古地理 鄂尔多斯盆地 平凉组 |
| 收稿时间： | 2017-04-27 |
Research on Relationship between Characteristics of Deep-water Deposits and Palaeoenvironment in the Ordovician,Pingliang Formation,Southern Margin of the Ordos Basin:A case of Zhaolaoyu countryside,Fuping town,Shaanxi province |
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| LI Hua,HE YouBin,HUANG Wei,LIU ZhuRuiZhi,ZHANG Jin.Research on Relationship between Characteristics of Deep-water Deposits and Palaeoenvironment in the Ordovician,Pingliang Formation,Southern Margin of the Ordos Basin:A case of Zhaolaoyu countryside,Fuping town,Shaanxi province[J].Acta Sedimentologica Sinica,2018,36(3):483-499. |
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| Authors: | LI Hua HE YouBin HUANG Wei LIU ZhuRuiZhi ZHANG Jin |
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| Institution: | 1.School of Geosciences, Yangtze University, Wuhan 430100, China;2.Key Laboratory of Exploration Technologies for Oil and Gas Resources, Ministry of Education, Yangtze University, Wuhan 430100, China;3.Research Center of Sedimentary Basin, Yangtze University, Wuhan 430100, China |
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| Abstract: | Deep-water deposits and relationship between palaeogeography is one key point and weak spot of sedimen-tology. Deep-water deposits well develop in Ordovician of Pingliang Formation in the southern margin of the Ordos Ba-sin. The lithology is mainly micrite, muddy micrite, mudstone and chert in local. Current ripple, small scale of cross bedding, and bioturbation structure are very formed. Three typical lithofacies are interbedded micrite, chert, mud-stone and tuff, bioturbated micrite, and massive bedded calcirudyte, corresponding to slope autochthonous deposits, contourites, and debrites, whose geochemical characteristics including δ13 C-δ18 O, Th-U, Ga-Cu, B-Cr, B-Ga, B-Sr, Ni/Co-U/Th,B/Ga-U/Thand 87 Sr/ 86 Sr-Sr/Ba show various. Slope autochthonous deposits and debrites are upwarding decreasing, and the contourites are reverse. The relative sea-level is rising, paleosalinity indicates multi-high to low change cyclicities, paleoclimate changes more and more arid, and reducing action is enhanced during the Pingliang stage. The relative sea-level is rising, paleosalinity change obviously, humid climate, and strong reducing action are helpful to contourites. By contrast, low relative sea-level, arid climate and tectonic movement contribute to debrites. |
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