...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Paleoceanography >Oceanic calcium changes from enhanced weathering during the Paleocene-Eocene thermal maximum: No effect on calcium-based proxies
【24h】

Oceanic calcium changes from enhanced weathering during the Paleocene-Eocene thermal maximum: No effect on calcium-based proxies

机译：在古新世-始新世热最大值期间，由于风化作用增强，海洋中的钙发生变化：对基于钙的代理没有影响

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

During the Paleocene-Eocene thermal maximum (PETM ～55 Myr ago), prominent climatic and biogeochemical changes took place in the atmosphere, ocean, and on land. For example, deep-sea temperatures rose by 5°C to 6°C, while sea surface temperatures at high latitudes increased by up to 9°C. In the sedimentary record, the onset of the PETM is marked by widespread dissolution of calcium carbonate on the seafloor. In addition, there is evidence for globally higher humidity, precipitation and increased weathering during the PETM. Both calcium carbonate dissolution and enhanced weathering probably affected the seawater calcium concentration. Here we investigate implications that possible changes in the ocean's calcium inventory may have had on boron/calcium (B/Ca) and magnesium/calcium (Mg/Ca) ratios, which are used as proxies for deep water carbonate chemistry and temperature, respectively. We also examine effects on δ~(44)Ca of seawater, which is used as an indicator for variations in the marine calcium cycle. We focus on the magnitude of change in the ocean's calcium ion concentration as a result of the carbon perturbation, which resulted in increased weathering fluxes and the dissolution of calcite on the ocean floor during the PETM. Different ranges of carbon input scenarios and their effect on ocean chemistry were examined using the Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir (LOSCAR) model. We found that under the most plausible scenario, the calcium ion concentration change (δ[Ca~(2+)]) was less than 0.7% and around 2% in the most extreme scenario. Our results show that B/Ca and Mg/Ca proxies were not affected within analytical precision by changes in oceanic calcium due to weathering and carbonate dissolution during the PETM. The most extreme scenario (δ[Ca~(2+)] = 2%) would result in ～4 μmol kg~(-1) uncertainty in reconstruction of [δCO_3~(2-)]. The same scenario affects the temperature reconstruction by ～0.2°C. The effect on the ocean's calcium isotope budget was insignificant as well, resulting in δσ~(44)Ca_(sw) of less than 0.05‰.
机译：在古新世-始新世最高温度（PETM〜55 Myr以前）期间，大气，海洋和陆地发生了明显的气候和生物地球化学变化。例如，深海温度上升了5°C至6°C，而高纬度地区的海面温度上升了9°C。在沉积记录中，PETM的开始以碳酸钙在海底上的广泛溶解为特征。此外，有证据表明，PETM期间总体上湿度更高，降水更多，风化程度更高。碳酸钙的溶解和增强的风化都可能影响海水中的钙浓度。在这里，我们研究了海洋钙库存量的可能变化可能对硼/钙（B / Ca）和镁/钙（Mg / Ca）比产生的影响，它们分别用作深水碳酸盐化学和温度的代理。我们还研究了对海水δ〜（44）Ca的影响，该作用被用作指示海洋钙循环变化的指标。我们关注由于碳扰动导致的海洋钙离子浓度变化的幅度，这导致在PETM期间增加了风化通量和方解石在海床的溶解。使用长期海洋-大气-沉积物碳循环碳库（LOSCAR）模型研究了碳输入情景的不同范围及其对海洋化学的影响。我们发现，在最合理的情况下，钙离子浓度变化（δ[Ca〜（2+）]）小于0.7％，在最极端的情况下约为2％。我们的结果表明，由于PETM期间的风化和碳酸盐溶解，海洋钙的变化不会影响B / Ca和Mg / Ca代理的分析精度。最极端的情况（δ[Ca〜（2+）] = 2％）将导致[δCO_3〜（2-）]的重建不确定性约为〜4μmolkg〜（-1）。同一场景会影响温度重建约0.2°C。对海洋钙同位素收支的影响也很小，导致δσ〜（44）Ca_（sw）小于0.05‰。

著录项

相似文献

  • 外文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号