Tropical glacier reconstructions during the Last Glacial Maximum in Costa Rica

  • Adolfo Quesada-Román Laboratorio de Geografía Física, Escuela de Geografía, Universidad de Costa Rica, San José, Costa Rica.
  • Néstor Campos Laboratorio de Teledetección Ambiental, Departamento de Ciencias Geográficas, Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha, Valparaíso, Chile.
  • Sebastián Granados-Bolaños Laboratorio de Geografía Física, Escuela de Geografía, Universidad de Costa Rica, San José, Costa Rica.
Keywords: glacier reconstruction, paleoglacier, ice thickness, equilibrium line altitude, Geomorphometry, Chirripó National Park, Costa Rica

Abstract

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 Area-Altitude 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.

Published
2021-03-24
Section
Articles