| 东海丽水凹陷早新生代沉积特征及物源演化 |
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| 引用本文： | 刘正华,侯元立,陈淑慧,廖凯飞,邵磊,朱伟林.东海丽水凹陷早新生代沉积特征及物源演化[J].地球科学,2022,47(7):2562-2572. |
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| 作者姓名： | 刘正华 侯元立 陈淑慧 廖凯飞 邵磊 朱伟林 |
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| 作者单位： | 1.上海自然博物馆(上海科技馆分馆), 上海 200041 |
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| 基金项目： | 国家科技重大计划2018YFE0202400国家自然科学基金项目42076066国家自然科学基金项目92055203 |
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| 摘 要： | 东海陆架盆地新生代发育大型弧后盆地，接受了海相及陆相沉积，油气资源丰富，勘探前景广阔. 其中，丽水凹陷发育了古新统?始新统扇三角洲、河流三角洲及滨浅海相沉积，其沉积环境及沉积物源研究一直存在争议. 通过古生物学和碎屑锆石U-Pb年龄谱系综合分析，对丽水凹陷古新统?始新统沉积环境及潜在源区进行系统的源汇对比研究. 结果表明，丽水凹陷古新统及下中始新统以滨浅海相为特征，凹陷东侧海水较深，沉积物主要来自周边燕山期岩浆岩古隆起. 然而，凹陷东、西次凹在沉积物源上存在明显差异，西次凹沉积物锆石U-Pb年龄谱系仅发育燕山期单峰，东次凹还存在明显的印支期物源；特别是进入始新世，东次凹温州组物源发生明显改变，出现大量古老锆石，沉积物来自北部渔山低隆起，显示该时期在凹陷北侧发育较大规模的三角洲沉积. 晚始新世，由于玉泉运动，丽水凹陷发生隆升剥蚀，直到中新世再次接受沉积. 丽水凹陷古新统?始新统以海陆过渡环境为主，有利于烃源岩及储集体的发育，具有良好的油气勘探潜力.
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| 关 键 词： | 东海 丽水凹陷 沉积环境 物源 锆石定年 石油地质学 |
| 收稿时间： | 2022-05-27 |
Early Cenozoic Sedimentary Characteristics and Provenance Evolution of Lishui Depression,East China Sea |
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| Abstract: | The East China Sea Shelf Basin generated a series of back-arc basins with thick successions of marine- and terrestrial-facies sediments during Cenozoic. It is enriched with abundant oil and gas resources and is of great significance to the petroleum exploration undertakings. Therein, the Lishui Depression formed fan delta, fluvial delta and littoral-to-neritic facies sediments during Paleocene-Eocene, and the research on its sedimentary environment and sediment source has been controversial. Combining detrital zircon U-Pb age spectra patterns with paleontological assemblages, a source-to-sink comparative analysis was conducted to restore the sedimentary environment and provenance evolution of the Lishui Depression during Paleocene-Eocene. In general, the Lishui Depression was dominated by littoral and neritic-facies environment during this time, corroborated by large abundance of benthic foraminifera, calcareous nannofossils and dinoflagellates. In addition, the eastern basin was featured with deeper water depths. The Lishui Depression was mainly influenced from the surrounding paleo-uplifts of Yanshanian magmatic rocks. However, its eastern area partly shows Indosinian populations compared to the dominance of Yanshanian clusters in the west. In particular, the Eocene Wenzhou sediments are characterized by increasingly plentiful Precambrian zircons in addition to the large Indosinian-Yanshanian peaks, indicating a possible impact from the Yushan Low Uplift to the east. Therefore, it is likely that the eastern Lishui Depression generated large river systems as well as deltas during this time. Due to the Yuquan Movement, the Lishui Depression experienced uplifting and exhumation in the late stage of the Late Eocene and sediments had not been deposited until Miocene. With transitional-facies depositions of Paleocene-Eocene, the Lishui Depression has great potential for source rock and oil-gas reservoir accumulation. |
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