Chondrite-normalized rare earth element (REE) data of a ~47.0-ka lake sedimentary sequence from the Dahu Swamp in the eastern Nanling Mountain area were used to determine climatic variations within the region. These sediments proved to be valuable proxies of climatic changes and their origin is discussed. The influences of grain size, organic matter absorption and Fe-Mn oxides on REE composition were determined to not be significant. The dominant source of sediments was ascertained to be the weathered granite residues from the catchment, enriched in light rare earth elements (LREE). Intensified East Asian summer monsoon (EASM) resulted in intensive chemical weathering, leading to enhanced REE and LREE fractionations in the weathered residues; this caused the increase in REE and LREE, and decrease in heavy rare earth element (HREE) fractionation degrees in the sediment. Therefore, our results indicate that changes in LREE/HREE, (La/Yb)_N, (La/Sm)_N) and (Gd/Yb)_N, the proxies of REE, LREE, and HREE fractionations, can serve as proxies of regional climate-induced chemical weathering and thus serve to constrain EASM changes.

中文翻译：

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南岭东部（华南）湖泊沉积物的稀土元素地球化学及其对过去~47 000年东亚季风相关化学风化的影响

来自南岭东部大湖沼泽的~47.0-ka湖沉积序列的球粒陨石归一化稀土元素（REE）数据用于确定该地区的气候变化。这些沉积物被证明是气候变化的重要代表，并讨论了它们的起源。晶粒尺寸、有机物吸收和 Fe-Mn 氧化物对 REE 组成的影响被确定为不显着。沉积物的主要来源被确定为来自集水区的风化花岗岩残留物，富含轻稀土元素 (LREE)。增强的东亚夏季风（EASM）导致强烈的化学风化作用，导致风化残留物中稀土元素和轻稀土元素的分馏增强；这导致了 REE 和 LREE 的增加，沉积物中重稀土元素（HREE）分馏度降低。因此，我们的结果表明 LREE/HREE 的变化，(La/Yb)_N , (La/Sm) _N ) 和 (Gd/Yb) _N是 REE、LREE 和 HREE 分馏的代表，可以作为区域气候引起的化学风化的代表，从而有助于限制 EASM 的变化。