EuroSpeleo 2016

World’s First Geophysical Surveys of Bat Guano

Oral|Dr George Veni

Abstract

Bracken Cave, Texas, USA, holds the world’s largest colony of bats, estimated at 40 million. But what is the depth of the bat guano that covers the floor? Working with Bat Conservation International and other partners, the US National Cave and Karst Research Institute conducted the world’s first geophysical surveys of bat guano. Using electrical resistivity methods and overcoming various technical challenges, the guano is estimated at about 35 m deep. Analyses of the results plus limited coring to date for paleoclimatic and paleoenvironmental research has verified some of the findings and found limitations to the method. Additional resistivity surveys will be run next year to refine the results, and reconfigured to see greater depths through the breakdown below the guano, and its underlying sediment, to map the underlying bedrock cave floor.