Evaluation of multiple weathering indices of fine-grained river sediments as climate proxies in subtropical and tropical South China

IF 5.4 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena Pub Date : 2024-09-19 DOI:10.1016/j.catena.2024.108408

Menglin Yang , Gang Li , Xiaowei Zhu , Yikai Ma , Zhiyong Liu

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引用次数: 0

Abstract

Geochemical and mineral compositions of river sediments are crucial for the understanding of continental weathering and climate changes in the past. Although fined-grained sediments were generally considered as reliable archives of past weathering history, the effectiveness of weathering indices and potential interference factors were rarely discussed seriously. This paper chooses modern river basins in subtropical–tropical South China to evaluate the effectiveness of multiple weathering indices of fine-grained fractions (<31 μm) as climate indicators. Results show that the CIA (chemical index of alteration) and WIP (weathering index of Parker) values of fine-silt fractions (2–31 μm) deviate the weathering trend of the clay fraction due to mineral sorting and sediment recycling. Chemical weathering intensity of clay fractions in river sediments agrees with soil data and shows positive correlations with modern temperature and precipitation in South China. However, multiple weathering indices of clay minerals are weakly correlative to climatic parameters due to the influence of parent rocks. We conclude that elemental proxies of clay fractions in fluvial deposits can better record the present-day weathering conditions in South China. For reconstructing the past climate changes in those small regions, the CIA of clay fractions is the most reliable climate indicator.

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作为华南亚热带和热带地区气候代用指标的细粒河流沉积物多重风化指数评估

河流沉积物的地球化学和矿物成分对于了解过去大陆风化和气候变化至关重要。尽管人们普遍认为细粒沉积物是过去风化历史的可靠档案，但很少认真讨论风化指数的有效性和潜在的干扰因素。本文选择亚热带-热带华南地区的现代河流流域，评估了细粒分（<31 μm）多种风化指数作为气候指标的有效性。结果表明，由于矿物分选和沉积物循环，细砂组分（2-31 μm）的化学蚀变指数（CIA）和帕克风化指数（WIP）值偏离了粘土组分的风化趋势。河流沉积物中粘土组分的化学风化强度与土壤数据一致，并与华南地区的现代气温和降水量呈正相关。然而，由于母岩的影响，粘土矿物的多重风化指数与气候参数的相关性较弱。我们的结论是，河流沉积物中粘土组分的元素代用指标能更好地记录华南地区现今的风化状况。对于重建这些小地区过去的气候变化，粘土组分的CIA是最可靠的气候指标。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Catena 环境科学-地球科学综合

CiteScore

10.50

自引率

9.70%

发文量

816

审稿时长

54 days

期刊介绍： Catena publishes papers describing original field and laboratory investigations and reviews on geoecology and landscape evolution with emphasis on interdisciplinary aspects of soil science, hydrology and geomorphology. It aims to disseminate new knowledge and foster better understanding of the physical environment, of evolutionary sequences that have resulted in past and current landscapes, and of the natural processes that are likely to determine the fate of our terrestrial environment. Papers within any one of the above topics are welcome provided they are of sufficiently wide interest and relevance.