Stalagmite records of northeast Mexican hydroclimate in the first millennium of the Common Era
Abstract
Many climate models show greater aridity throughout Mexico due to future climate warming. However, instrumental data and existing paleoclimate archives show that precipitation throughout Mexico has substantial interannual- to decadal-scale variability and spatial differences. The Climate Investigations with Mexican Archives (CIMA) Project aims to better understand the relationship between NE Mexican hydroclimate, Northern Hemisphere summer insolation, and changes in Atlantic and/or Pacific sea surface temperatures, as reflected in speleothems and tree rings. Here we present one portion of this work: initial results from two stalagmites sampled from the same cave chamber in San Luis Potosi, Mexico. U-series dating shows that the stalagmites grew between 50 and 1050 CE, with some rapid growth phases (exhibiting visible, 1 mm-thick growth layers) and some slower phases (dense, without visible growth layers) and potential hiatuses. We use oxygen and carbon stable isotope ratios and trace element ratios as proxies for regional precipitation amount (δ18O) and local water balance (δ13C, Mg/Ca). Initial results indicate high coherence between Mg/Ca and both types of stable isotope measurements. This suggests that they are controlled by the same climate signals and are therefore suitable paleohydrology proxies. The three proxies show several multi-decadal dry periods between 50 and 1050 CE. We plan to test reproducibility within and between stalagmites to better characterize the robustness of the records. These data will also be combined with ongoing monitoring efforts and newly developed records from nearby caves (in San Luis Potosi and Tamaulipas, Mexico) and tree rings to assess spatial and temporal differences in climate signals. Taken together, this work will assist in building a stronger understanding of northeast Mexican paleoclimate and future hydrological changes.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMPP42B..05S
- Keywords:
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- 4916 Corals;
- PALEOCEANOGRAPHY;
- 4920 Dendrochronology;
- PALEOCEANOGRAPHY;
- 4928 Global climate models;
- PALEOCEANOGRAPHY;
- 4932 Ice cores;
- PALEOCEANOGRAPHY