Radiocarbon Age Offsets Between Two Surface Dwelling Planktonic Foraminifera Species During Abrupt Climate Events in the SW Iberian Margin.
Radiocarbon Age Offsets Between Two Surface Dwelling Planktonic Foraminifera Species During Abrupt Climate Events in the SW Iberian Margin.
复制标题
西伊比利亚边缘突发气候事件期间两种表层浮游有孔虫物种之间的放射性碳年龄抵消。
DOI：
10.1029/2018pa003490
复制
发表时间：
2019
影响因子：
3.5
通讯作者：
Ausín B
中科院分区：
文献类型：
--
作者：
Ausín B
本研究确定了来自西南伊比利亚边缘（所谓的沙克尔顿遗址）沉积物岩心中浮游有孔虫物种gloigerina bulloides和gloigerinoides rubber（白色）的放射性碳年龄的时间偏差。外壳的浸出和渗滤液和浸出样品的放射性碳含量的测量使我们能够确定测试的表面污染及其对其14c年龄的影响。较年轻的放射性碳在外壳上的结合对两个物种都有影响，对内核的影响更大。对浸出样品的14c年龄进行物种间比较，揭示了g的14c年龄有系统的偏移。橡胶是年轻的东西。在末次消冰期和全新世早期和中期的部分时期。最大的偏移（长达1030年）出现在Heinrich Stadial 1、新仙女木期和全新世的部分时期。通过互补14c、氧和碳同位素以及物种丰度测定，评估了影响这两种浮游物种差异的潜在因素。生物扰动与g丰度变化的耦合效应。用Ruberis来解释大的年龄偏移。我们的研究结果强调，浮游有孔虫的14c年龄可能在很大程度上受到损害，即使在以高沉积速率为特征的环境中。因此，在使用14c年龄进行古气候调查或放射性碳校准之前，必须对潜在的时间偏差进行仔细评估（例如，海洋校准曲线Marine13， Reimer等人，2013,https://doi.org/10.2458/azu_js_rc.55.16947）。
This study identifies temporal biases in the radiocarbon ages of the planktonic foraminifera speciesGlobigerina bulloidesandGlobigerinoides ruber(white) in a sediment core from the SW Iberian margin (so‐calledShackleton site). Leaching of the outer shell and measurement of the radiocarbon content of both the leachate and leached sample enabled us to identify surface contamination of the tests and its impact on their14C ages. Incorporation of younger radiocarbon on the outer shell affected both species and had a larger impact downcore. Interspecies comparison of the14C ages of the leached samples reveal systematic offsets with14C ages forG. ruberbeing younger thanG. bulloidesages during the last deglaciation and part of the Early and mid‐Holocene. The greatest offsets (up to 1,030 years) were found during Heinrich Stadial 1, the Younger Dryas, and part of the Holocene. The potential factors differentially affecting these two planktonic species were assessed by complementary14C, oxygen and carbon isotopes, and species abundance determinations. The coupled effect of bioturbation with changes in the abundance ofG. ruberis invoked to account for the large age offsets. Our results highlight that14C ages of planktonic foraminifera might be largely compromised even in settings characterized by high sediment accumulation rates. Thus, a careful assessment of potential temporal biases must be performed prior to using14C ages for paleoclimate investigations or radiocarbon calibrations (e.g., marine calibration curve Marine13, Reimer et al., 2013, https://doi.org/10.2458/azu_js_rc.55.16947).