We investigated the detrital influx, chemical weathering intensity, provenance and pedogenesis over the past 2,500 years in the catchment of Pookot Lake, southern India. The down-core variations of metal/Al ratios (Na/Al, K/Al, Mg/Al, Ca/Al, Fe/Al, Mn/Al, Zn/Al, Ba/Al) of the Pookot sediments indicate changes in the rainfall-induced terrigenous inflow to the lake. In contrast, fluctuations in the chemical index of alteration (CIA) and Rb/Sr values denote the variability in the strength of chemical weathering in the watershed of the lake. The results show that the detrital influx, and hence rainfall, remained steady except during 1500–600 cal. years B.P. (high) and 600–300 cal. year B.P. (low) in the Pookot lake catchment. However, the periods of high/low chemical weathering intensity in the catchment do not correspond to periods of high/low detrital influx to the lake basin. The similar shale-normalized rare earth elemental curves point to a uniform provenance. The past pedogenic activity is indicated by pedogenic χ_lf and pedogenic χ_fd derived from citrate-bicarbonate-dithionite (CBD) extraction. The data indicate that the fine-grained magnetite/maghemite formed during the pedogenesis mainly contributes to the magnetic signal of sediments. The degree of pedogenesis was strong during 2500–2000 cal. years B.P. and moderate throughout 1500–600 cal. years B.P. The pedogenic intensity became stronger again during ~ 600 cal. years B.P., which weakened between 600 and 300 cal. years B.P. and remained steady thereafter. The present study indicates that detrital influx proxies like metal/Al ratios are more suitable for reconstructing past climate in tropical climate rather than chemical weathering indices.

我们调查了印度南部普科特湖流域过去 2,500 年来的碎屑流入、化学风化强度、来源和成土作用。 Pookot 沉积物的金属/铝比（Na/Al、K/Al、Mg/Al、Ca/Al、Fe/Al、Mn/Al、Zn/Al、Ba/Al）的下核变化表明降雨引起的陆源水流入该湖。相反，化学蚀变指数 (CIA) 和 Rb/Sr 值的波动表示湖泊流域化学风化强度的变化。结果表明，除 1500-600 cal 期间外，碎屑流入以及由此产生的降雨保持稳定。年 BP（高）和 600–300 cal。 Pookot 湖流域的年份 BP（低）。然而，流域化学风化强度高/低的时期与湖盆碎屑流入高/低的时期并不对应。类似的页岩归一化稀土元素曲线表明其来源一致。过去的成土活动由源自柠檬酸盐-碳酸氢盐-连二亚硫酸盐 (CBD) 提取的成土 χ _lf和成土 χ _fd表示。数据表明，成土过程中形成的细粒磁铁矿/磁赤铁矿主要对沉积物的磁信号有贡献。 2500~2000cal期间成土作用较强。年 BP 和中度 1500–600 cal。年 BP 成土强度在 ~ 600 cal 期间再次变强。年 BP，减弱在 600 至 300 cal 之间。年 BP 并此后保持稳定。目前的研究表明，金属/铝比率等碎屑流入指标比化学风化指数更适合重建热带气候的过去气候。