建湖冈西剖面全新世沉积物源示踪及其对苏北盆地水系调整的指示

    PROVENANCE OF THE HOLOCENE SEDIMENTS IN THE JIANHU GANGXI SECTION AND THE IMPLICATIONS FOR THE DRAINAGE SYSTEM ADJUSTMENT OF THE SUBEI BASIN

    • 摘要: 建湖冈西剖面全新世陆相沉积保存了区域水系调整的记录,对其进行物源示踪研究对了解全新世以来苏北盆地水系变迁、盆地演化以及我国东部陆海相互作用均具有重要意义。通过对建湖冈西剖面全新世以来的陆相沉积物进行了碎屑锆石U—Pb年龄测试, 并将其与区域可能物源端元水系对比,结果表明:建湖冈西剖面沉积物碎屑锆石年龄分布较一致,主要表现为7组年龄区间:分别为 < 200、200~350、350~550、700~1 100、1 300~1 600、1 700~2 100和2 400~2 600 Ma。长江、黄河、淮河及废黄河作为可能物源端元,其沉积物碎屑锆石U—Pb年龄分布存在较明显的差异。通过剖面与水系沉积物碎屑锆石U—Pb年龄组成的对比认为, 自建湖地区成陆作用以来,该区域受到淮河流域的影响较大,废黄河对其有一定的影响,长江、黄河流域对该地区的物质贡献较少。

       

      Abstract: The provenance of the Holocene continental deposits in the Jianhu Gangxi Section, as the records of regional change in drainage system, is significant to the understanding of the river system adjustment and the evolution of the Subei Basin, especially to the investigation of the interaction between land and sea. Special attention is paid by the authors to the sources of the Holocene deposits of the Jianhu Gangxi Section using the detrital zircon U-Pb as a tool. The zircon age distribution pattern and the comparison with regional source drainage show that the Quaternary sediments of the Jianhu Gangxi Section could be subdivided into seven age groups: < 200, 200~350, 350~550, 700~1 100, 1 300~1 600, 1 700~2 100 and 2 400~2 600 Ma. As possible sources, the zircon age distribution patterns of the Yangtze River, the Yellow River, the Huai River and the Feihuanghe are rather different. Since the area became land, the Huai River has remained the main sediment source of the Jianhu area and the Feihuanghe has made certain contribution to the sedimentation while the contributions of the Yangtze River and the Yellow River remain negligible.

       

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