松嫩平原全新世黑土14C年龄-深度关系空间格局  

Spatial distribution of 14C age and depth of mollisol sections in the Songnen Plain during the Holocene

作　　者：崔静怡 郭利成 陈雨露 王恒 杨石岭[1,2] 熊尚发 CUI Jingyi;GUO Licheng;CHEN Yulu;WANG Heng;YANG Shiling;XIONG Shangfa(Key Laboratory of Cenozoic Geology and Environment,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049)

机构地区：[1]中国科学院地质与地球物理研究所,中国科学院新生代地质与环境重点实验室机构,北京100029 [2]中国科学院大学机构地球与行星科学学院,北京100049

出　　处：《第四纪研究》2021年第5期1332-1341,共10页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:42007282和42077409);国家重点研发计划项目"全球变化及应对"重点专项项目(批准号:2017YFA0603404);中国科学院地质与地球物理研究所重点部署项目(批准号:IGGCAS-201905)共同资助。

摘　　要：准确评估土壤有机碳储量及其变化的一个关键,是明确全新世土壤形成年龄-深度关系的空间格局。本文利用松嫩平原12个典型黑土剖面的56个AMS 14C年龄数据,尝试重建全新世黑土14C年龄与形成深度的空间分布模式。结果显示:1)研究区黑土大范围形成时间不晚于8.5 cal.ka B.P.;2)研究区黑土形成年龄的分布由深度40 cm以下阶段性均匀分布转为40 cm以上南北向"三明治"模式(南北老,中部新);3)研究区黑土形成深度分布在4 cal.ka B.P.之前和降水梯度变化密切相关,4~3 cal.ka B.P.在研究区东南部显著变浅,3~0 cal.ka B.P.几乎阶段性呈均匀分布,而在1~0 cal.ka B.P.研究区近中心区域反而出现低谷。结合区域气候变化、地貌演化和人类活动历史,推测松嫩平原黑土大范围形成与东亚夏季风边缘区全新世早期-适宜期植被大范围生长扩张有关,研究区黑土形成年龄的分布在40 cm以上可能主要受毗邻沙丘活动影响,在40 cm以下可能主要受全新世适宜期稳定气候影响,黑土形成深度的分布可能主要由4 cal.ka B.P.之前的降水控制转变为之后的自然风力侵蚀和人类活动影响。Spatially explicit distribution of the formation age and depth of Holocene soils plays a critical role in assessing soil organic carbon storage and its changes.Specifically,on the time scale of section,the utilization of the formation age,instead of depth,of Holocene soils in estimating soil organic carbon storage provides the accumulated information on carbon storage,and offers an effective way to spatially assess carbon storage.However,on the regional or global scale,there are large knowledge gaps in spatial distribution of the formation age and depth of Holocene soils.The Holocene mollisol covered area of Northeast China with high organic carbon content is one of the best preserved areas,where many integrally-exposed Holocene mollisol sections can be found in the region.Based on this judgment,we select the mollisol covered area of Songnen Plain as the study region,where 4014C dating samples were newly collected from QQHED1,QQHEE1,DQB1,NJC4,BAC2,HEBA1,SHE1,BQE2 and NHA1,together with 16 published 14C dating samples were collected from PM1908,PM1910 and Huangshan sections.All 14C dating ages were calibrated to calendar years before present(B.P.)(B.P.=1950 CE)using the BetaCal 4.2 and/or OxCal 4.4 radiocarbon age calibration program with the IntCal 20 curve,prior to spatial analysis using ArcGIS 10.2.Thus,we present the first detailed compilation of 56 AMS 14C dating ages of 12 typical mollisol sections in the Songnen Plain,which we use to analyze spatial variations in 14C age and depth of Holocene mollisol in the region and to determine the main causal mechanisms.The results show thatΔ14C values are<0,suggesting that the environment contained organic carbon of the buried Holocene mollisol can be regarded as a closed system.It enables that the AMS 14C dating age could constrain the formation age of mollisol during the Holocene.The radiocarbon ages then reveal that the formation age of a large area of mollisol preceded 8.5 cal.ka B.P.in the Songnen Plain,corresponding to wide growth and expansion of vegetation du

关 键 词：黑土 全新世 14C年龄 松嫩平原 

分 类 号：P597.3[天文地球—地球化学] S151[天文地球—地质学]