Tropical glacier reconstructions during the Last Glacial Maximum in Costa Rica
Fecha
2021-03-24
Tipo
artículo original
Autores
Quesada Román, Adolfo
Campos, Néstor
Granados Bolaños, Sebastián
Título de la revista
ISSN de la revista
Título del volumen
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Resumen
Numerosas altas montañas tropicales muestran evidencia de
actividad glacial durante el Último Máximo Glacial (UMG) y han sido
documentadas alrededor del mundo. El Cerro Chirripó, en Costa Rica,
presenta formas de relieve paleoglaciares como circos glaciares, depósitos
de morrenas, así como superficies de roca pulida y estriada. Utilizamos
imágenes aéreas (1:25000) y curvas de nivel para obtener un Modelo
Digital de Elevación (MDE) del UMG. Determinamos las altitudes
de las líneas de paleoequilibrio (paleo-ELAs) usando el Area-Altitude
Balance Ratio (AABR) durante el UMG para el Cerro Chirripó en Costa Rica. Además, se realizó un Modelo Lineal Generalizado (MLG)
para analizar estadísticamente los volúmenes de los paleoglaciares y el
espesor del hielo combinados con diez parámetros de superficie terrestre
(PST). Nuestros resultados determinaron treinta y un paleoglaciares que
cubrían un área de 28.26 km2
durante el UMG global, con un espesor
máximo de hielo de 178 metros en el Cerro Chirripó, un volumen total
de 13863 × 105
m3
y un paleo-ELA medio de 3490 metros. Además,
Área y Pendiente fueron los PST con mayor correlación estadística para
explicar los volúmenes paleoglaciares, mientras que Área y Calentamiento
Anisotrópico Diurno (CAD) fueron los mejores parámetros para el espesor
del hielo paleoglaciar. Como uno de los primeros estudios en los ambientes
tropicales de alta montaña, este trabajo expande el alcance geográfico de
las reconstrucciones de glaciares durante la máxima expansión del UMG.
Numerous high elevation tropical mountains around the world show evidence of past glacial activity during the Last Glacial Maximum (LGM). Cerro Chirripó in Costa Rica exhibits paleoglacial landforms such as glacial cirques, moraine deposits and polished and striated bedrock surfaces. We used aerial imagery (1:25000) and contour lines to develop a Digital Elevation Model (DEM) for the LGM. We determined paleo-equilibrium line altitudes (paleo-ELAs) using AreaAltitude Balance Ratio (AABR) during the LGM for Cerro Chirripó in Costa Rica. Additionally, a Generalized Linear Model (GLM) was performed to statistically analyze the paleoglacier volumes and ice thickness combined with ten land surface parameters (LSP). Our results identified thirty-one paleoglaciers covering an area of 28.26 km2 during the global LGM, with a maximum ice thickness of 178 meters in Cerro Chirripó, a total volume of 13863 × 105 m3 and a mean paleo-ELA of 3490 meters. In addition, Area and Slope were the LSP with the highest statistical correlation to explain the paleoglacier volumes, while Area and Diurnal Anisotropic Heating were best for the paleoglacier ice thickness. As one of the first studies in the tropical high mountain environments, this work expands the geographic scope of glacier volume and thickness reconstructions during the maximum expansion of the LGM.
Numerous high elevation tropical mountains around the world show evidence of past glacial activity during the Last Glacial Maximum (LGM). Cerro Chirripó in Costa Rica exhibits paleoglacial landforms such as glacial cirques, moraine deposits and polished and striated bedrock surfaces. We used aerial imagery (1:25000) and contour lines to develop a Digital Elevation Model (DEM) for the LGM. We determined paleo-equilibrium line altitudes (paleo-ELAs) using AreaAltitude Balance Ratio (AABR) during the LGM for Cerro Chirripó in Costa Rica. Additionally, a Generalized Linear Model (GLM) was performed to statistically analyze the paleoglacier volumes and ice thickness combined with ten land surface parameters (LSP). Our results identified thirty-one paleoglaciers covering an area of 28.26 km2 during the global LGM, with a maximum ice thickness of 178 meters in Cerro Chirripó, a total volume of 13863 × 105 m3 and a mean paleo-ELA of 3490 meters. In addition, Area and Slope were the LSP with the highest statistical correlation to explain the paleoglacier volumes, while Area and Diurnal Anisotropic Heating were best for the paleoglacier ice thickness. As one of the first studies in the tropical high mountain environments, this work expands the geographic scope of glacier volume and thickness reconstructions during the maximum expansion of the LGM.
Descripción
Palabras clave
Glacier reconstruction, Paleoglacier, Ice thickness, Equilibrium line altitude, Geomorphometry, Chirripó National Park, Reconstrucción glaciar, Paleoglaciar, Grosor de hielo, Altitud de la línea de equilibrio, Geomorfometría, Parque Nacional Chirripó, COSTA RICA