Quaternary lava tubes in northern Hainan Island: Morphology and significance of comparative planetology

Lava tubes are common basaltic products of Quaternary volcanism in the Earth, that mainly outcropped in pahoehoes and 'a '(alpha) over bar lavas as important parts of a basaltic lava transport system. There are abundant lava tubes distributed in Quaternary basalt regions of China. Although a great deal of research work had been carried out on the lava landforms, magma geneses and evolutionary histories of the Quaternary basalts, little attention has been paid to the lava tubes. However, the study of lava tubes is of great significance for understanding the migration process of a lava flow and the evolution of the surface lava tectonic landforms. More importantly, a large number of potential lava tubes have been discovered in the basaltic lava regions of the Moon and Mars in recent years, and these huge tubular underground spaces are the preferred candidates for establishing stable shelters on rocky extraterrestrial planets. The comparative planetary study of the Earth's lava tubes can provide important clues for exploring the morphological characteristics of the extraterrestrial lava tubes. Therefore, in this paper, we carried out detailed morphological and comparative planetary studies on the lava tunnel groups in the northern Hainan Island in order to provide morphological information for further exploration of the characteristics and size of the lava tubes in the Moon and Mars.