Glacial valley erosion controls on subsurface hydrology: Speleogenesis of Stortuvhola cave, sub-Arctic Norway

We use Stortuvhola cave, developed in a narrow Caledonian marble band in sub-Arctic Norway, as an archive to study the interplay between glacial and interglacial hydrological regimes. We integrate detailed cave surveying, sedimentological mapping, U-Th dating of a relict flowstone, and high-resolution DTM analysis of the Aspfjordelva basin to reconstruct the cave's evolutionary history and its geomorphic context. Three superposed phreatic levels are identified: (i) a relict, sediment-choked upper tier; (ii) an extensive mid-level effluent maze attributed to ice-contact speleogenesis; and (iii) a lower active network that captured a modern stream. Keyhole canyons incised into the mid- and lower levels indicate two major vadose phases driven by valley deepening. U-Th ages provide a broad minimum age of 318 ka for the onset of vadose conditions in the upper passages although uncertainties remain. Surface analysis reveals numerous knickpoints, and possible remnants of former valley floors, implying a stepwise glacial erosion and southeastward migration of fluvial incision following successive glacial retreats. We propose a conceptual model in which alternating glacial and interglacial conditions progressively lowered the regional water table, re-organized drainage connectivity, and modulated speleogenetic rates. Dolines and collapse chimneys document late glacial to Holocene capture of surface runoff, sustaining the present streamway while leaving the youngest phreatic conduits essentially dry. In combination, cave and surface records capture at least three glacial–fluvial cycles and highlight the primary role of drainage connectivity relative to lithology and fracture density on subsurface hydrology in high-latitude marble karst. • Three phreatic cave levels record stepwise glacial valley deepening since 318 ka. • Ice-contact speleogenesis formed mid-level effluent maze during glacial phases. • Drainage connectivity controls subsurface hydrology in marble stripe karst. • Valley incision rate of 0.43 mm/a over three glacial-fluvial cycles • Surface knickpoints correlate with cave levels linking glacial-karst evolution.