Prehistoric and Colonial land-use in the Chihuahuan Desert as inferred from pollen and sedimentary data from Coahuila, Mexico

Pollen, along with context sedimentary data of two desert bottom sites in South Coahuila, Mexico reconstruct Holocene environment in the Chihuahuan Desert in relation to possible human influence on vegetation during the Holocene. Examined pollen sites here derive from the margins and bottoms of the playa lake of the Laguna Mayran (LM). First, at the reported site of Cuota 4 (LM4), archaeologically dated deposits of the initial Spanish Colonial period here are correlated with a xeric environment, followed by an Early Modern mesic period of increased rainfall with wetland plants. Second, at the reported site of Coahuila Highway 30 (CH30), unconformable, discontinuous deposits with intermittent representation of Early, Middle and Late Holocene sedimentation are analyzed showing periodic changes in hydrology. At CH30, possible cultivation, based on Cucurbitaceae pollen, occurs in a defined ‘wet’ phase dating to circa 1500 BP. Finally, origins of pollen taphonomy at CH30 are defined by analog samples from the Chihuahuan desert zone in the Menchacas Basin near Cuatro Cienegas are analyzed. The pilot pollen analog study is based on inferred pollen recruitment mechanics in different sediments as well as moss pollsters in the Menchacas basin in the Chihuahuan Desert in Middle Coahuila.