利用钍-230(230Th)修正的钍-232(232Th)重建古风尘通量研究进展及其在西太平洋的应用

风尘通过影响大气辐射平衡和海洋生态系统的营养物质供应从而调控全球气候,是国际学术界广泛关注的热点问题之一。近年来,风尘的相关研究取得一系列重要进展,并提出将²³²Th作为一种准确重建约50万年以来风尘沉积通量的途径。本文首先介绍基于²³⁰Th的标准化方法,它可用于修正由于海洋底流频繁扰动引起的沉积物沉积速率变化,然后结合²³⁰Th标准化方法修正后的232Th通量,并利用10.5μg/g换算得出的风尘沉积通量,通过和实测值对比,阐明了此方法的准确性。进一步通过对比晚全新世与末次冰盛期²³⁰Th标准化后的基于²³²Th获取的风尘沉积通量,也验证了此方法的可靠性。通过总结该方法在西太平洋的前期应用,认为此方法在西太平洋有着广阔的应用前景。

The 230Th-normalized 232Th method in reconstructing paleo-dust flux and its applications in the Western Pacific

Eolian dust constitutes a potent modulator in the global climate by altering the radiative balance of the atmosphere and iron supply to the global ocean.In particular,the thorium-based method has been evoked to calibrate the sedimentary mass accumulation rate(MAR)for the past~500,000 years,which offers an important approach for reconstructing paleo-dust flux accurately.Here,²³⁰Th normalization,an appealing approach to calibrate MAR,is comprehensively deconvolved.In conjunction with ²³²Th,novel ²³⁰Th-normalized data synthesis is compiled to elucidate the precision of this method with the aid of the measured value,which ultimately in line with the Th-derived result by using convert parameter uniformly(i.e.10.5μg/g).Further,comparison of the dust reconstruction based on this approach between Late Holocene and the Last Glacial Maximum(LGM)also indicates the validation of this method.Within this context,²³⁰Th-normalized ²³²Th serves as a reliable proxy in determining dust input to the global ocean and thus can unveil unambiguous interpretation with respect to the reconstruction of paleo-dust flux to the western Pacific during the Late Quaternary.In contrast,the paucity of applications based on this method in the western Pacific is found,by summarizing previously published dissertations,with implication of foreshadowing a broad future in utilizing this tool at the western Pacific.