摘要
大型流域盆地化学风化对全球海陆物质循环和气候变化有着显著影响。许多学者提出了不同的化学风化指数,并对影响因素进行了研究。然而,目前对化学风化强度的定量刻画以及化学风化控制因素的认识仍存在不足。以长江和珠江流域盆地水系沉积物地球化学数据为例,利用化学蚀变指数(CIA)和帕克风化指数(WIP)定量刻画了化学风化强度,利用趋势面分析完成了空间分布特征研究,同时基于空间相关分析完成了化学风化强度同气温和降水的相关性分析。获得了以下结果:(1)长江流域CIA平均值为72.9,WIP平均值为34.2,指示中等强度风化;珠江流域CIA平均值为93.8,WIP平均值为6.4,指示强风化。(2)趋势面分析显示化学风化强度存在由北向南逐渐增强的趋势。局部地区的CIA和WIP异常值与该地区较高的年降水量和年均气温相吻合。(3)长江和珠江流域的化学风化同气候条件紧密相关。研究区内CIA和WIP同年均降水量和年均气温的相关系数均在0.85以上。综上,认为CIA和WIP可以作为定量刻画流域盆地化学风化强度的指标,趋势面分析较好地刻画了区域及局部分布特征。
Chemical weathering in large-scale drainage basins has significant effects on cycling of sea and land matters and climatic change on Earth. Various sediment geochemical proxies have been proposed to study the influencing factors of chemical weathering intensity. However, quantitative description of chemical weathering intensity and knowledge of controlling factors of chemical weathering are still insufficient.Exemplified by the sediment geochemical data from the Yangtze River and Pearl River Basins,the chemical weathering intensity was quantified by Chemical Index of Alteration(CIA) and Weathering Index of Parker(WIP). In addition,the spatial distribution characteristics were studied by using Trend Surface Analysis(TSA),and the correlation of the chemical weathering intensity with temperature and precipitation was completed based on Spatial Correlation Analysis(SCA). The following results were obtained:(1) The average values of the CIA and WIP in the Yangtze River Basin are 72.9 and 34.2,indicating an intermediate weathering intensity. The average values of the CIA and WIP in the Pearl River Basin are 93.8 and 6.4,indicating a strong weathering degree.(2) The TSA shows that the distribution of chemical weathering intensity has obvious latitude effect,that is,the lower the latitude,the stronger the chemical weathering.(3) The abnormal values of the CIA and WIP coincide with a higher annual temperature and precipitation in space. Meanwhile,the correlation coefficients of the CIA and WIP with annual precipitation and annual mean temperature are all above 0.85 in the study area. In conclusion,the chemical weathering in the Yangtze River and the Pearl River Basin is mainly controlled by climatic conditions. The CIA and WIP can be used as a quantitative indicator for the chemical weathering intensity in drainage basins,and the trend surface analysis well depicts the regional and local distribution characteristics.
作者
常海钦
付亚龙
林鑫
张苗苗
孟刚刚
Chang Haiqin;Fu Yalong;Lin Xin;Zhang Miaomiao;Meng Ganggang(School of Earth Science and Resources,Chang'an University,Xi'an 710054,China;Xi'an Space-Time Geology and Mineral Technology Co],Ltd],Xi'an 710068,China)
出处
《地球科学进展》
CAS
CSCD
北大核心
2019年第1期93-102,共10页
Advances in Earth Science
基金
科技部重点研发计划项目"穿透性地球化学勘查技术"(编号:2016YFC0600601)资助~~
关键词
流域盆地
化学风化强度
趋势面分析
长江流域
珠江流域
Drainage basin
Chemical weathering intensity
Trend surface analysis
Yangtze River Basin
Pearl River Basin
