PIT CRATERS AND OPEN VERTICAL VOLCANIC CONDUITS OF EARTH AND MARS

Mid-2011 review of the web command "pit crater Mars" revealed ongoing misunderstandings of occurrence and basic geology of terrestrial pit craters accompanied by confusion between pit craters, open vertical volcanic conduits (OVVCs), "cinder sinkholes", skylights of lava tube caves, and crevice caves in general. We affirm the "Pit Crater District of Hawaii" as the type locality for at least three types of pit craters and review seminal definitions and their application to deep black holes and funnel-shaped pits observed on Mars. We differentiate vertical entrances of crevice caves from both OVVCs and pit craters. We discuss the divergent origins of Hawaii's Devil's Throat and Malekule Craters together with that of Furna do Enxofre, an incipient pit crater on Portugal's Graciosa Island. We link origins of pit craters and OVVCs at Hawaii's Na One (a vertical pit complex 263 meters deep) and shallower features on the northwest rift zone of Hualalai volcano. We compare Hawaii's water-filled Kauhako Crater Pit (plumbed to 248 meters) and Portugal's Algar do Carvao (a shallower OVVC in rhyolite with multiple magma chambers) with Iceland's Thrihnukagigur (a world-class OVVC about 185 meters deep). We segregate Hawaii's Wood Valley Pit Crater and "Jeanne" on Mars' Arsia Mons from other pit craters because of their internal structures. We confirm 1993 priority in publication of the term "cinder sinkhole" for funnel-shaped pits along crevices in poorly consolidated material at Hawaii's Kilauea Caldera but propose its replacement with the term "funnel pit" for such features on both Earth and Mars.