40-kyr of environmental history of the southeastern sector of paleolake Cuitzeo, central-western Mexico: Insights from abiotic and biotic proxies

We present a multiproxy reconstruction of environmental changes recorded in the southeastern sector of Lake Cuitzeo (central-western Mexico) over the last ∼40 kyr. Our study integrates abiotic (major-element geochemistry, rock-magnetic parameters, pH, and electrical conductivity) and biotic proxies (diatoms and pollen) from a ∼10 m-long sedimentary core (Cz-07). This multiproxy approach provides a robust framework for identifying variations in terrigenous input, redox conditions, nutrient availability, carbonate precipitation, and hydrological balance, as well as the response of local vegetation to climate fluctuations. Comparing the Cz-07 record with previous data from a depocenter core reveals some spatial differences in the lake’s sensitivity to environmental changes. The sequence indicates generally low lake levels between ∼42 and ∼26.5 kyr BP, followed by pronounced environmental variability during the Last Glacial Maximum, including a marked dry episode at its onset. Enhanced runoff and predominantly oxic conditions characterize the interval from ∼17.5 to ∼11 kyr BP, encompassing the Bølling–Allerød and Younger Dryas events. During the early-to-middle Holocene (∼11.7–5 kyr BP), a progressive shift toward arid conditions is evidenced by increased carbonate precipitation, higher salinity, and reduced runoff. The most severe drought occurred during the middle Holocene, causing a substantial contraction of the lake’s southeastern sector. This arid phase aligns with middle Holocene drying trends reported in other lacustrine records across central Mexico.