A Review of δ18O Proxy Measurements in South and Central America

MÜLLER GABRIELA V.; REPINALDO CINTIA R.; RICARTE RITA M.

Mendoza

Congreso; XI Congreso Argentino de Meteorología (CONGREMET XI); 2012

Centro Argentino de Meteorólogos

Over the last decades, progress has been made with the use of proxy data to reconstruct large scale patterns, being δ18O proxy very sensitive to climate variations. However, data are scarce, particularly in South America. With the purpose of identifying the existent δ18O proxies in South America, despite the difficulties in finding available or consistent data, 24 proxies were identified and divided into five categories: ice cores, tree rings, caves, corals and lakes. Regarding ice cores, a large variability can be observed in δ18O concentrations, being Huascarán the most variable one (10,11‰). Mercedário is the ice core yielding the lowest values, distinguishing from the others for its geographic location. Among the tree rings, Volcán Granada distinguishes from the others for its highest values, sometimes above 33‰. Despite its large variability (8,9‰), Volcán Granada is not the one reporting the highest values. Tree 67 in Puerto Maldonado yields the highest variability (11,2‰), as well as the lowest value (20,7‰) among tree rings, being the proxies from trees 78 and 82 (3,6 and 3,7‰, respectively) the less variable ones. Among the caves, Cascayunga and Perdida have very low amplitude, of around 1,9 ‰. Due to their different geographic location and elevation, Perdida cave displays considerably larger values than Cascayunga does, with a difference of about 4,8‰. The coral formations also exhibit different behaviors, being Montego Bay the most distinguishable one, given its depth, much more deeper than the others. Except for Montego bay and Secas, the other corals (including Urvina with distant latitude) show the highest values, similar, and not much variable, being one of the Bucoo Reef corals the one accounting for the highest recorded values (-2,6‰) regarding superficial measurements. Among the lakes, Guanaco, located at higher latitudes and a low elevation, as compared to the others, presents the lowest values, reaching -4,3‰, and the smallest amplitude (3,18‰). Both Miscanti and El Peinado lakes exhibit similar behavior, although their amplitudes differ in approximately 2‰. Further studies should be conducted in order to incorporate more δ18O proxy data to the Southern and Central America dataset, for a better understanding of past, present and future climate changes.