ABSTRACT
The Last Glacial Termination (T1) featured major changes in global circulation systems that led to a shift from glacial to interglacial climate. While polar ice cores attest to an antiphased thermal pattern at millennial timescales, recent well-dated moraine records from both hemispheres suggest in-phase fluctuations in glaciers through T1, which is inconsistent with the bipolar see-saw paradigm. Here, we present a glacier chronology based on 30 new 10Be surface exposure ages from well-preserved moraines in the Lago Palena/General Vintter basin in northern Patagonia (~ 44°S). We find that the main glacier lobe underwent profound retreat after 19.7 ± 0.7 ka. This recessional trend led to the individualization of the Cerro Riñón glacier by ~ 16.3 ka, which underwent minor readvances at 15.9 ± 0.5 ka during Heinrich Stadial 1, during the Antarctic Cold Reversal with successive maxima at 13.5 ± 0.4, 13.1 ± 0.4, and 13.1 ± 0.5 ka, and a minor culmination at 12.5 ± 0.4 ka during Younger Dryas time. We conclude that fluctuations of Patagonian glaciers during T1 were controlled primarily by climate anomalies brought by shifts in the Southern Westerly Winds (SWW) locus. We posit that the global covariation of mountain glaciers during T1 was linked to variations in atmospheric CO2 (atmCO2) promoted by the interplay of the SWW-Southern Ocean system at millennial timescales.
Subject(s)
Ice Cover , Wind , Antarctic Regions , ClimateABSTRACT
Se analiza el comportamiento balístico de dos tipos de perdigones "menos letales" usados por las fuerzas policiales en Chile para entender mejor los factores fundamentales que conllevan a la inusual cifra de lesiones oculares en el marco de las manifestaciones masivas ocurridas en Chile desde octubre de 2019. Para evaluar los riesgos de penetración y trauma ocular severo, se construyeron curvas de energía normalizada (E/a) en base a información publicada por las fuerzas policiales y fabricantes de municiones. Aun cuando el riesgo asociado al uso de las municiones según protocolos es leve, este artículo presenta que de todas formas existe riesgo de trauma ocular severo en todas las distancias de uso. La balística de los perdigones, combinada con la imprecisión de municiones multiproyec-tiles, son factores importantes para explicar la alta incidencia de trauma ocular severo. El caso de Chile es parte de un aumento global en la incidencia de lesiones oculares causadas por municiones consideradas menos letales, lo cual demanda una reevaluación de las políticas que regulan su uso.
The ballistic characteristics of two types of "less-lethal" multi-projectile shotgun rounds used by law enforcement in Chile are analyzed to better understand their contribution to the unusually high occurrence of ocular injuries at mass demonstrations since October 2019. Normalized energy (E/a) curves are constructed using publicly-available information from law enforcement and the manufacturers of the munitions to evaluate the risks of skin penetration and severe ocular trauma. Although the risk of penetration is small when these munitions are used according to local protocols, the risk of severe ocular trauma exists at all distances of approved use, and the ballistics of these pelletsalong with the imprecision of multi-projectile shotgun roundshelp to explain the high inci-dence of severe ocular trauma. The example of Chile is part of a worldwide acceleration in the incidence of ocular injuries by "less-lethal" munitions and demands a reevaluation of their suitability for crowd control.
