Hydrodynamic processes and source changes caused elevated 14C ages of organic carbon in the East China Sea over the last 14.3 kyr
Hydrodynamic processes and source changes caused elevated 14C ages of organic carbon in the East China Sea over the last 14.3 kyr
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过去14.3 kyr中，水动力过程和来源变化导致东海有机碳14C年龄升高
DOI：
10.1016/j.gca.2021.04.015
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发表时间：
2021-04
影响因子：
5
通讯作者：
Zhao Meixun
中科院分区：
文献类型：
--
作者：
Zhang Hailong;Li Da-Wei;Sachs Julian P.;Yuan Zineng;Wang Zicheng;Su Chenglong;Zhao Meixun
超过80%的海洋有机碳(OC)埋藏在边缘海的沉积物中。沉积OC14C年龄比共同沉积的海岸和远洋沉积物早几千年，已经有很好的记录，但这种现象的原因仍然不确定。我们测量了东中国海沉积岩芯中有机碳的14C和13C含量，以及陆相和海相脂肪生物标志物的沉积含量，以评估和量化过去14.3KYR以来控制有机碳年龄的过程。我们发现，在1930-5530年 年，有机碳的14C年龄一直比共沉积沉积物的年龄更早。计算的总有机碳(TOC-AIR)视初始放射性碳年龄的时间变化反映了海平面的变化，海侵(14.1-7.8KYR BP)具有较高的值(4570 ± 1250 KYR年)，中晚全新世(7.8-0 KYR BP)的值较低(3170 ±KYR 670年)，表明海侵导致的海岸线撤退减少了早期陆地有机碳向边缘海的输送。然而，基于δ13C和Δ14C端元的总体OC14C年龄始终比来自长江、黄河和海洋来源的三元混合的预期年龄更早。因此，我们认为，泥沙运移过程中的水动力过程以及来自陆地和水下海岸的早期有机碳的增加是造成这些老的有机碳年龄及其时间变化的主要因素。在海侵过程中，TOC-空气值在海平面较低时较高，这表明海侵过程中海岸沉积物的侵蚀可能贡献了旧的有机碳。由于海平面稳定，7.8KYR BP的水动力作用是造成OC~(14)C年龄偏高的主要原因。全新世中晚期流体动力老化过程的重要作用被认为是由于河口和沉积物沉积中心之间较长的运移距离，可以容纳额外的沉积-再悬浮回路。
More than 80% of marine organic carbon (OC) burial occurs in sediments of marginal seas. Sedimentary OC14C ages up to several millennia older than co-deposited coastal and pelagic sediments have been well documented but the cause of this phenomenon remains uncertain. We measured14C and13C contents of OC, along with the sedimentary content of terrestrial and marine lipid biomarkers, in sediment cores from the East China Sea to evaluate and quantify processes controlling OC ages over the last 14.3 kyr. We find that14C ages of OC were persistently older than co-deposited sediments by 1930–5530 yr. Temporal variations of the calculated apparent initial radiocarbon ages of total OC (TOC-AIR) mirrored sea level changes, with higher values (4570 ± 1250 yr) during the transgression (14.1–7.8 kyr BP) and lower values (3170 ± 670 yr) during the mid-late Holocene (7.8–0 kyr BP), suggesting that transgression-induced coastline retreat reduced the transport of pre-aged terrestrial OC to the marginal sea. However, bulk OC14C ages were consistently older than those expected from ternary mixing of Changjiang (Yangtze River), Huanghe (Yellow River) and marine sources based on δ13C and Δ14C end-members. We therefore propose that hydrodynamic processes during sediment transport and the addition of pre-aged OC from land and submerged coast were the main factors contributing to these old14C ages of OC and their temporal variations. During the transgression, higher TOC-AIR values were observed during times of lower sea-level, which suggests that erosion of coastal deposits during transgression might have contributed old OC. Since sea level stabilized 7.8 kyr BP hydrodynamic processes were the primary cause of high14C ages of OC. The significant role for hydrodynamic aging processes during the mid-late Holocene is hypothesized to result from longer transport distances between river mouths and sediment depocenters which can accommodate additional deposition-resuspension loops.
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影响因子：
5.8
作者：
N. Drenzek;K. Hughen;D. Montluçon;J. Southon;G. Santos;E. Druffel;L. Giosan;T. Eglinton
通讯作者：
N. Drenzek;K. Hughen;D. Montluçon;J. Southon;G. Santos;E. Druffel;L. Giosan;T. Eglinton
东海济州岛西南部末次冰消期和全新世沉积物物源判别
影响因子：
3
作者：
Dou Yanguang;Yang Shouye;Lim Dhong-Il;Jung Hoi-Soo
通讯作者：
Jung Hoi-Soo
影响因子：
3
作者：
Benner, R
通讯作者：
Benner, R
影响因子：
16.6
作者：
Bröder L;Tesi T;Andersson A;Semiletov I;Gustafsson Ö
通讯作者：
Gustafsson Ö
影响因子：
2.9
作者：
E. Leithold;N. Blair;L. Childress;B. Brulet;M. Marden;A. Orpin;S. Kuehl;C. Alexander
通讯作者：
E. Leithold;N. Blair;L. Childress;B. Brulet;M. Marden;A. Orpin;S. Kuehl;C. Alexander