Carbon isotopes (δ¹³C_org) in biomass, carbon (δ¹³C_carb) and oxygen (δ¹⁸O_carb) isotopes in authigenic calcite and estimations of chemical weathering of siliciclastic minerals (chemical index of alteration [CIA] and plagioclase index of alteration [PIA]) in lacustrine sediments of the ephemeral Babicora Basin, located within the core region of the North American Monsoon at northwest Mexico, helped to evaluate the source of biomass, variations in hydrological balance and sediment–water interactions during three different marine isotope stages (late MIS 4: ≥65.4–59.5 cal ka BP, MIS 3: ~59.5–28 cal ka BP and MIS 2: ~28–15 cal ka BP) of the last glacial. Comparisons of δ¹³C_org with previously published records of C/N, diatom abundance and fossil pollen indicate that biomass of the late MIS 4 was sourced from C₃ aquatic and land plants. During the MIS 3, the C₃ plants continued to contribute biomass and the influence of lacustrine algae, however, increased during its later part. The water column experienced more evaporation compared to two other MIS stages and sediment–water interactions varied between minimal to moderate (CIA: 49–68). Sediments were transported for longer distances during the wetter intervals and eroded from nearby lithologies during the drier intervals. Interactions between sediments and inflowing water (CIA: 59–65) remained homogeneous during the MIS 2. Source of the biomass, however, was variable. Lacustrine algae and C₃ land plants contributed biomass during the early MIS 2 (~28–19 cal ka BP) and contributions from the C₄ and CAM vegetation slightly increased towards the deglaciation (~19–15 cal ka BP).

中文翻译：

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墨西哥西北部北美季风核心区最后冰川湖沉积物的地球化学：生物量，水文平衡和化学风化的来源

碳的同位素（δ ¹³ C ^_有机）在生物量，碳（δ ¹³ C ^_{碳水化合物}）和氧（δ ¹⁸ ö_{碳水化合物}）同位素在自生方解石和硅质矿物的化学风化（化学蚀变指数的[CIA]和斜长石指数的估计位于墨西哥西北部北美季风核心区的短暂巴比科拉盆地湖相沉积物中的蚀变[PIA]）有助于评估三种不同海洋同位素期间生物量的来源，水文平衡的变化以及沉积物-水之间的相互作用末次冰期的晚期（MIS 4：≥65.4–59.5 cal ka BP，MIS 3：〜59.5–28 cal ka BP和MIS 2：〜28–15 cal ka BP）。δ的比较¹³具有先前已公开的C / N，硅藻丰度和化石花粉记录的C _org指出，MIS 4晚期的生物量来自C ₃水生和陆地植物。在MIS 3中，C ₃植物继续贡献生物量，湖藻的影响在后期有所增强。与其他两个MIS阶段相比，水柱的蒸发更多，并且沉积物与水之间的相互作用在最小到中等之间变化（CIA：49-68）。在较湿的时间间隔内，沉积物被运输了更长的距离，而在较干燥的时间间隔内，沉积物被附近的岩性侵蚀。在MIS 2期间，沉积物与流入水之间的相互作用（CIA：59-65）保持均质。然而，生物质的来源却是可变的。Lacustrine藻类和C ₃陆地植物在MIS 2早期（〜28–19 cal ka BP）贡献了生物量，而C ₄和CAM植被在冰消作用下的贡献略有增加（〜19–15 cal ka BP）。