Equifinality and unusual genesis of closed depressions in a mixed carbonate/igneous terrain

Abstract

Closed depressions such as sinkholes and pits can form through various subsurface processes, leading to similar surface expressions. This study analyzes closed depressions in eastern Galilee, Israel, to evaluate their potential origins. Ten depressions were surveyed, including shallow bowl-like forms and steep-walled pits. The terrain comprises faulted Cretaceous carbonates intruded by Early Pleistocene basalts dated to around 2.25 Ma. The circular morphology of the depressions and lack of ejecta indicate collapse into subsurface voids. Field evidence and geophysical data reveal a complex interplay of tectonic and volcanic factors. Some depressions appear to be structurally controlled by dilational normal faults, while others appear to be associated with volcanic features like dikes. Karst processes in the soluble carbonates likely contributed, most probably by hypogene dissolution related to magmatic fluids which may have enhanced void development. A dike identified within depressions suggests void formation through inflation and deflation of intrusions. Progressive collapse and erosion modified steep pits into shallow bowl-like depressions over time. Our results highlight the equifinality of closed depressions, wherein similar morphologies can arise through multiple subsurface processes. Unraveling this complexity has significance for interpreting pit craters on planetary surfaces using remote sensing.