By Lonnie G. Thompson
Earth’s highest tropical mountain, Nevado Huascarán (9.1oS; 77.6oW; 6756 masl) in the Cordillera Blanca, Peru, is the only documented site in the deep Tropics that sits above the Amazon Basin and contains an unaltered ~20 ky history of climatic and environmental variability. The 2019 Ice core drilling project on Huascaran resulted in the successful recovery of 471.6 meters of ice cores.
Two cores were drilled to bedrock in the col; Col core A (CCA) is 165 m in length, and Col core B (CCB) is 168.6 m in length and measured ice/bedrock temperatures of -4oC.
In addition, two ice cores were drilled to bedrock on the summit of the South Peak.
Summit core A (SCA) and Summit core B (SCB) are 69.33 m and 68.73 m long, respectively with measured ice/bedrock temperatures of -9oC. SCA and SCB are the highest elevation ice cores to be collected from a Southern Hemisphere glacier (Fig. 1).
The goal of the Methane and d180air project funded by VoLo Foundation was to produce the first high resolution record of methane and d18Oair for ice cores recovered from the world’s highest tropical mountain Huascaran, in the Andes of Peru. This was an attempt to establish the first tropical methane history covering the last 20,000 years to use the d18Oair and methane records to establish a well constrained time scale, that is essential the proper interpretation of the climate and environmental records from these cores.
This research is a collaborative effort between teams under Profs. Ed Brook, Oregon State University, Prof. Jeffrey Severinghaus (SCRIPPS) and our team at The Ohio State University.
Air recovered from the air bubbles in the Huascaran ice cores represents air that has flowed over the vast Amazon Basin by the Easterlies before rising over the Andes Mountain range. We are hoping to use these new measurements along with other ice core parameters already underway to investigate possible past “tipping points” in the Amazon Basin driven by natural climate variation over the past 20,000 years.
