贵州梵净山九龙池沉积物14C年代学研究及全新世碳累积速率变化

放射性碳同位素加速器质谱(ASM¹⁴C)测年法是湖泊沉积物定年的主要方法，并且是全新世年代学研究的热点。随着对全新世古气候与环境变化研究的深入，选取不同介质定年可能对年代模型的准确性造成误差，进而影响到气候指标的解译。本文选取贵州东北部梵净山九龙池沉积物中树枝、树叶、树皮、种子等植物残体和全样有机质作为测年介质，利用ASM¹⁴C进行定年。结果表明，相比全样有机质，使用植物残体定年可以在一定程度上避免碳库效应的影响。但相比于原位沉积且生长年限较短的叶片，树枝的定年结果偏老，不是一种理想的定年介质。另外，根据定年结果及总有机碳含量重建了全新世九龙池的碳累积速率，发现碳累积速率可以指示该地区亚洲夏季风强度的变化历史。

A Study on the 14C Chronology of Jiulongchi Wetland Deposit on the Fanjingshan Mountain and Its Carbon Accumulation Rate during the Holocene

AMS¹⁴C dating is the main method for dating lake sediments, and is a hot spot in the study of Holocene chronology. With the further study of Holocene paleoclimate and environmental changes, the accuracy of dating results is required to be higher. Choosing FJ19A core bulk samples and plant residues as ASM¹⁴C dating material, we show that selecting plant residues as dating sample material instead of bulk samples can avoid carbon effect to some extent, the branches is not an ideal material for dating and the dating results often larger than the real results. Compared with bulk samples, seeds, bark, and leaf is closer to the real dates. In addition, based on the ASM¹⁴C results, we reconstructed the sedimentation rate and carbon accumulation rate of Jiulongchi during the Holocene, and then compared it with several paleo-environmental records during the Holocene. We found that the carbon accumulation rate can well restore the paleoclimatology of Fanjingshan Mountain area, so it can be used as a good proxy indicator of the strength of Asian monsoon activity in this area.