刘健, 段宗奇, 梅西, 刘青松, 张训华, 郭兴伟, 吴志强, 王红, 王飞飞, 陈彬, 张欣, 安郁辉. 南黄海中部隆起晚新近纪—第四纪沉积序列的地层划分与沉积演化[J]. 海洋地质与第四纪地质, 2021, 41(5): 25-43. DOI: 10.16562/j.cnki.0256-1492.2021101701
引用本文: 刘健, 段宗奇, 梅西, 刘青松, 张训华, 郭兴伟, 吴志强, 王红, 王飞飞, 陈彬, 张欣, 安郁辉. 南黄海中部隆起晚新近纪—第四纪沉积序列的地层划分与沉积演化[J]. 海洋地质与第四纪地质, 2021, 41(5): 25-43. DOI: 10.16562/j.cnki.0256-1492.2021101701
LIU Jian, DUAN Zongqi, MEI Xi, LIU Qingsong, ZHANG Xunhua, GUO Xingwei, WU Zhiqiang, WANG Hong, WANG Feifei, CHEN Bin, ZHANG Xin, AN Yuhui. Stratigraphic classification and sedimentary evolution of the late Neogene to Quaternary sequence on the Central Uplift of the South Yellow Sea[J]. Marine Geology & Quaternary Geology, 2021, 41(5): 25-43. DOI: 10.16562/j.cnki.0256-1492.2021101701
Citation: LIU Jian, DUAN Zongqi, MEI Xi, LIU Qingsong, ZHANG Xunhua, GUO Xingwei, WU Zhiqiang, WANG Hong, WANG Feifei, CHEN Bin, ZHANG Xin, AN Yuhui. Stratigraphic classification and sedimentary evolution of the late Neogene to Quaternary sequence on the Central Uplift of the South Yellow Sea[J]. Marine Geology & Quaternary Geology, 2021, 41(5): 25-43. DOI: 10.16562/j.cnki.0256-1492.2021101701

南黄海中部隆起晚新近纪—第四纪沉积序列的地层划分与沉积演化

Stratigraphic classification and sedimentary evolution of the late Neogene to Quaternary sequence on the Central Uplift of the South Yellow Sea

  • 摘要: CSDP-2孔位于南黄海中部隆起,其孔深超过2800 m。该孔中下部中—古生代的固结成岩地层已被深入研究,但其最上部592 m未固结成岩的沉积序列尚未有研究报道。为了确定这部分沉积序列的地层划分,揭示其沉积演化历史,我们对其开展了古地磁测试、光释光测年、底栖有孔虫鉴定和沉积相分析,并与南黄海及其邻近海岸地区以往钻孔岩心分析成果进行对比研究。结果表明,CSDP-2孔0~592.00 m沉积序列最初形成于约5.2 Ma,其第四系底界位于孔深约227.91 m(年龄为2.59 Ma),下/中更新统界线位于孔深约65.23 m(年龄为0.78 Ma),中/上更新统界线位于孔深47.34 m(年龄约128 ka);自晚更新世以来形成的地层又可划分出MIS 5、MIS 4、MIS 3和MIS 1的沉积层段, MIS 2沉积缺失。南黄海中部隆起区在新近纪的剥蚀止于约5.2 Ma,从约5.2 Ma至约1.7 Ma发育河流沉积;由于浙闽隆起的逐渐沉降,约1.7 Ma发生自新生代以来的首次海侵,直至约0.83 Ma,发育潮坪—滨岸沉积与河流沉积的互层;从约0.83 Ma开始至今,浙闽隆起进一步沉降使得南黄海中部隆起区在间冰期高海平面时期的海洋环境基本接近现今环境;南黄海西部陆架在MIS 5发育范围比现今更广的冷水团沉积,在MIS 4、MIS 3早期、MIS 3晚期至MIS 2和MIS1分别依次发育河流、三角洲、河流和滨岸—内陆架环境。该沉积序列主要受控于区域构造沉降和海平面变化,其全新统、更新统及整个地层序列的沉积速率呈现依次明显下降的趋势,主要归因于地层时代越老其连续性越差,特别是晚更新世之前的地层有显著侵蚀的现象。本文的研究成果为深入理解南黄海西部陆架区晚新近纪以来的沉积环境演化进程和沉积地层的形成机制提供了新证据。

     

    Abstract: The Core of CSDP-2, which is more than 2800 m long, was retrieved from the Central Uplift of the South Yellow Sea, of which the Mesozoic-Paleozoic strata of the core have become a hot topic under research. However, research results of the uppermost sequence, 592 m in thickness made up of unconsolidated loose sediments, have not yet been reported so far. We have carried out paleomagnetic measurements, optically stimulated luminescence (OSL) dating, identification of benthic foraminifera and analyses of sedimentary facies for the sequence, in order to make its stratigraphic classification and reveal its history of sedimentary evolution. The results indicate that the 592 m- thick sequence came into being about 5.2 Ma, with its Quaternary bottom boundary at ~227.91 m of 2.59 Ma, the Lower and Middle Pleistocene boundary at ~65.23 m of 0.78 Ma, and the Middle - Upper Pleistocene boundary at 47.34 m of 128 ka, and covered by the Upper Pleistocene, which could be further subdivided into several sedimentary intervals formed during MIS 5, MIS 4, MIS 3 and MIS 1, while the MIS 2 deposits are missing. Also the results demonstrate that the denudation took place on the Central Uplift during Neogene and came to an end at ~5.2 Ma, followed by the deposition of fluvial deposits from ~5.2 to ~1.7 Ma, which was ceased as the first marine transgression took place in the region since Cenozoic presumably due to subsidence of the Zhe-Min Uplift. From ~1.7 to ~0.83 Ma, there was an alternation of tidal-flat and coastal deposits, and then from ~0.83 to the present the marine environments during high sea-level stands of the interglacial times were close to the marine environment of today in the region, due to the further subsidence of the Zhe-Min Uplift. On the western shelf of the South Yellow Sea, there was a cold water mass during MIS 5, which is broader than that of nowadays, and fluvial, deltaic, fluvial and coastal to inner-shelf environments prevailed successively during MIS 4, early MIS 3, late MIS 3 to MIS 2, and MIS 1. The sedimentary sequence was primarily controlled by tectonic subsidence and sea-level changes, and the sedimentation rates decreased evidently from the Holocene deposits to the Pleistocene and to the whole sequence, owing to the incompleteness of the older sediments comparing to the younger ones. Especially the pre-Late Pleistocene strata are marked by distinct erosion. The results of this study have provided new evidence for better understanding the evolution of sedimentary environments and the formation mechanism of strata in the western South Yellow Sea shelf since late Neogene.

     

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