Registro de resúmenes

Reunión Anual UGM 2023


SE18-4

 Resumen número: 0057  |  Resumen aceptado  
Presentación oral

Título:

POSSIBLE IMPACT OF AMOC ON DROUGHT DYNAMICS IN PALEOCLIMATE REGISTERS FROM (SEMI-HUMID) CENTRAL-SOUTHERN AND (SEMI-ARID) NORTH-EASTERN MEXICO

Autores:

1 Priyadarsi D. Roy ← Ponente
Instituto de Geología, UNAM
roy@geologia.unam.mx

2 Oscar Agesandro García-Arriola ED
Posgrado en Ciencias del Mar y Limnología, UNAM
agess301290@hotmail.com

3 Jose Luis Sanchez-Zavala
Instituto de Geología, UNAM
jlsz@unam.mx

4 Ma. Patricia Giron-García
Instituto de Geología, UNAM
pgiron@geologia.unam.mx

5 Irma Gabriela Vargas-Martínez EL
Facultad de Ingeniería, UNAM
irmagav@gmail.com

Sesión:

SE18 Cambio climático y variabilidad climática: perspectivas actuales y desafíos futuros Sesión especial

Resumen:

In paleoclimate registers, the drought evaluation with respect to the El Niño/Southern Oscillation, Pacific Decadal Oscillation, Atlantic Multi-Decadal Oscillation and latitudinal shifts in the Inter-Tropical Convergence Zone has provided valuable baseline data about the relationship between some of the atmospheric and oceanic forcing and the Late Quaternary environmental conditions in different parts of Mexico. The Atlantic Meridional Overturning Circulation or AMOC is another essential climate forcing and it controls heat transportation from low to high latitudes within the Atlantic Ocean, persistently, at least since the last interglacial. Its strength has changed in response to the sea-ice coverage and to catastrophic iceberg discharge during the Heinrich Stadials. The cessation of AMOC has occurred twice close to the last glacial maximum. Presently, it is in the weakest state of the last millennium and might weaken further over the next millennium from doubling of CO2 in atmosphere, consistent with the Intergovernmental Panel on Climate Change (IPCC) projections. Under this scenario, it is important to understand the hydroclimate changes occurred in different parts of Mexico during the intervals of variable AMOC strength through the evaluation of paleoclimate registers. Here, we attempt to document the response of lacustrine ecosystems from semi-humid central-southern (Lake Coatetelco, 18º N) and semi-arid northeastern (El Potosi Basin, 25º N) parts of Mexico by comparing the hydroclimate dynamics reconstructed through high-resolution elemental geochemistry and fractionations of δ18Ocarb and δ13Ccarb as well as δ13Corg in sedimentary archives to different modes of AMOC. In Lake Coatetelco, the diminished watershed erosion, enhanced water column salinity and minimal influence of organics on the dissolved bicarbonate during the two different phases of weaker AMOC contemporary to Heinrich stadial 1(HS1, off mode) and Younger Dryas (YD, cold) reflected increase in aridity. In the drought prone El Potosi Basin, the hydroclimate changes indicated reduced precipitation during the off modes of AMOC contemporary to HS1 and HS2. A depositional hiatus and positive excursion in δ18Ocarb might also be reflecting arid conditions during the weak AMOC of YD. These observations in geological registers might be useful for a regional evaluation for better drought mitigation planning in the possible scenario of more-frequent drought-like events in near future.





Reunión Anual UGM 2023
29 de Octubre al 3 de Noviembre
Puerto Vallarta, Jalisco, México