Magnetic record of El Niño Southern Oscillation in Late Pleistocene sediments from Mucubají lake (western Venezuela)

El Nino Southern Oscillation (ENSO) is an internal forcing of the climate system. This event has an actual frequency of 2 to 8 years. Evidence from a paleoclimate proxy database of gray scale (GS), in samples from Pallcacocha lake in Ecuador, indicates that the ENSO had a frequency of 35 to 75 years during the Late Pleistocene. In this work we explored the possible relationship between the ENSO proxies (GS) from Pallcacocha and magnetic parameters from sediments sampled at the Mucubaji lake in Merida, Venezuela (i.e. mass-specific magnetic susceptibility, magnetic remanence S ratio and susceptibilitynormalized saturation isothermal remanent magnetization). After applying a Lanczos bandpass filter to the rock magnetic and the GS data, in order to remove, as much as possible, frequencies associated to any periodic event other than ENSO, we found significant correlations between GS and magnetic parameters for the period between 12450 and 10560 cal. yrs BP. These relationships were obtained using an Adaptive Neuro Fuzzy Inference System (ANFIS), a hybrid algorithm that combines fuzzy logic with neural networks. The results show that the magnetic parameters obtained in Mucubaji are able to explain 50.5% of the total variance of the ENSO proxy in a range of 35 to 75 years in Pallcacocha, which is roughly the same percentage of the total variance of the temperature in the Venezuelan Andes, explained by the ENSO at present times. In this way we have inferred a possible influence of the ENSO in the Venezuelan Andes during the Late Pleistocene.