Recurrent droughts over the Holocene compared to the wetter deglaciation at eastern and northeastern Mexico and decoupling of the forcing mechanisms

Global climate change of last two millennium and associated hydroclimatic variations in central and southern Mexico have been linked to the socio-cultural transitions at several Mesoamerican urban centers. The increase in well-mixed greenhouse gases since the industrial revolution, however, has led to an ascent in mean temperature, and the projections for later part of this century include further depletion in precipitation and soil moisture, affecting the crop yield and immigration both from the rural and urban regions of Mexico. New multi-proxy paleoclimate data about the droughts since the LGM were inferred from the sedimentary archives of Lake Totolcingo (19°N) and paleo-lake Cieneguilla (22°N), located at the east and northeast of Mexico with similar precipitation regimes (summer-autumn) and moisture sources, i.e. the Atlantic Ocean. Both the basins are present-day agriculture hubs and situated close to important Classic and Postclassic archeological sites. The lake area mapping and stable isotope compositions of surface water reflected the annual precipitation and its seasonality. Paleoclimate records obtained from the stable isotopes (C, H and N), grain size, magnetic property and elemental concentrations in organic and inorganic components of the lacustrine archives suggested homogeneity in the organic productivity during the latest Pleistocene deglaciation with the millennial-scale fluctuations in catchment erosion and lake water salinity coupling with the oxygen isotope fractions of Greenland ice core and dynamics of ITCZ position during the stadial and interstadial. Recurrent droughts over the Holocene were reflected in enhanced aeolian activity in lake catchments, reduced runoff and more carbonate deposition. Enhanced aridity was also reflected in organic productivity dominanted by C4 plants. This arid interval in orbital-scale was coupled with phases of low spring insolation and high autumn insolation and decoupled from the Greenland ice core and ITCZ dynamics. The first-order similarity with Golf of Mexico SST suggested autumn insolation modulated warmer Atlantic surface water was the principal driver of droughts. This multiproxy dataset addresses challenges from the interbedded tephra layers and possible hiatus for accurate regional climate reconstructions and furture uncertainities from the global warming.