Stratigraphy and Sedimentology of the Upper Pleistocene to Holocene Lake Chalco Drill Cores (Mexico Basin)

The Basin of Mexico is a high elevation (2240 m asl), large (9540 km2), tectonic endorheic basin developed in the central-eastern Trans-Mexican Volcanic Belt. In 2016, the ICDP MexiDrill project recovered a total of 1152 m of sediments from a maximum depth of 520 m in Lake Chalco, in the SW of the Basin of Mexico. The upper 309.15 m (composite sequence, mc) are composed of fine-grained lacustrine sediments alternating with discrete visible tephra layers, and the lower 200 m are primarily volcaniclastic facies and basaltic lavas with some intercalated fluvial and alluvial facies. Initial lacustrine deposition started in the Chalco Basin, after the deposition of a thick volcaniclastic sequence, and continued until the lake was drained in recent centuries. Lake Chalco has remained as a shallow lake until the present day.