Holocene tephrostratigraphic framework and monsoon evolution of East Asia: Key tephra beds for synchronising palaeoclimate records
Holocene tephrostratigraphic framework and monsoon evolution of East Asia: Key tephra beds for synchronising palaeoclimate records
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全新世火山地层格架与东亚季风演化：同步古气候记录的关键火山岩层
DOI：
10.1016/j.quascirev.2020.106467
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发表时间：
2020-08
影响因子：
4
通讯作者：
Xuan‐Yu Chen;S. Blockley;Yigang Xu;M. Menzies
中科院分区：
文献类型：
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作者：
Xuan‐Yu Chen;S. Blockley;Yigang Xu;M. Menzies
在东亚，我们对全新世气候变化、强迫机制和传播的理解需要对古气候记录进行精确的时间控制，以实现数据集的稳健整合。然而，现有的主要基于 14 C 方法的年表不足以限制有关一个世纪内国家之间过渡中发生的气候突变的关键问题。广泛分散的火山灰层允许沉积档案的精确年代和同步，为整合记录提供了时间顺序框架，特别是在可见火山灰记录通过添加隐火山灰（不可见灰烬）进行补充的情况下。然而，尽管该地区进行了大量的火山灰研究，但还没有一个全面的全新世火山灰框架。为了解决这个问题，我们对在日本进行的全新世火山灰调查进行了彻底的审查。利用广泛的火山灰床，我们提出了一个综合的火山灰框架，并提出了将其建立为东亚更广泛方法的前进方向。该框架基于 22 个灰层，这些灰层主要来自日本，也有少量来自中国/朝鲜、韩国和俄罗斯。每个火山灰都根据年代学、地球化学和分布进行评估。该框架与东亚的高分辨率古气候记录进行了比较。利用这一点，我们证明了季风演变的区域变化，更重要的是，火山灰等时线在限制这种变化方面的潜力。鉴于在那些解析良好的古气候记录中对火山灰层的识别很少，我们主张更系统地使用隐火山灰方法，这可能会导致东亚火山灰年代学和该地区古气候档案的相关性取得重大进展。
In East Asia our understanding of Holocene climate change, forcing mechanisms and propagation, require the precise chronological control of palaeoclimate records to allow robust integration of data sets. The existing chronologies, predominantly based on14C method, however, are not sufficient to constrain key questions about abrupt climate shifts that occur within a century in the transitions between states. Widely dispersed tephra layers allow precise dating and synchronisation of sedimentary archives, providing a chronological framework for integrating records, especially where the visible tephra record is complemented by the addition of cryptotephra (non-visible ash). Despite significant tephra studies in this region, however, a comprehensive Holocene tephra framework is not available. To address this issue, we carry out a thorough review on Holocene tephra investigations undertaken in Japan. Using widespread tephra beds we present an integrated tephra framework and suggest the way forward for establishing this as a wider approach for East Asia. The framework is based on twenty-two ash layers that are mainly from Japan, and to a lesser extent China/N Korea, S Korea and Russia. Each tephra is assessed in terms of chronology, geochemistry and distribution. The framework is compared with high resolution palaeoclimate records from East Asia. Using this we demonstrate regional variations in monsoon evolution and more importantly, the potential of tephra isochrons in constraining such variations. Given the scarce identification of tephra layers in those well-resolved palaeoclimate records, we advocate a more systematic employment of the cryptotephra method, which would potentially lead to a significant advance in East Asian tephrochronology and the correlation of palaeoclimate archives in the region.