Inception and Evolution of La Corona Lava Tube System (Lanzarote, Canary Islands, Spain)

Abstract

Growing interest in studying large terrestrial lava tubes is motivated in part by their analogy with their extra-terrestrial counterparts. However, on Earth, the formation of such structures is still poorly understood. Here, the lava tube system of La Corona (Lanzarote, Canary Islands, Spain) is studied to identify how pre-existing stratigraphy can govern a lava tube's evolution. Combining terrestrial laser scanner technology with field observations and geochemical analyses of the pre-existing lava enabled us to reconstruct the three-dimensional geometry of the lava tube system, the paleo-surface trough which it developed, and the volcanic series into which it carved its path. We show that a pyroclastic layer played a key role in the development of the lava tube. The layer—Derived from late Quaternary Strombolian activity—Is traceable along almost the full length of the tube path and defines the paleo-topography. The excavation process mostly happens because of the mechanical strength of the substrate, that controls the widening of the growing lava tube. Other influential parameters controlling erosion include slope variations of the paleo-surface (i.e., knickpoints), and the lava physical properties. Since weak layers such as regolith are a common feature of extra-terrestrial lava flows, the processes seen at La Corona to the may be highly relevant to the development of planetary lava tube systems.