Dual sediment transport pathways to a distal turbiditic system in the Early Cretaceous late-rift stage basin (Outer Carpathians, Poland)

Deep-marine depositional systems in rift basins often feature complex sediment routing from multiple sources, yet distal parts, especially in rifting settings, remain poorly understood. This study documents the sedimentary architecture of the Valanginian gravity currents deposits in four sections (Krzyworzeka, Lipnik, Dziadkowka, and Potok pod Padoly) of the Silesian Unit, Outer Western Carpathians (southern Poland). These deposits record distal gravity flows-system accumulation during the late-rift stage of the Proto-Silesian Basin which developed along the northern Tethys margin adjacent to the North European Platform from Late Jurassic to Early Cretaceous.

Detailed logging, facies analysis, and paleotransport measurements reveal interaction between two systems at the slope-to-basin-floor transition. Dominant facies comprise very thin-bedded turbidites (mainly Tb–Tc Bouma intervals) forming mudstone-dominated rhythmic sandstone–mudstone couplets, deposited by dilute, sustained low-density gravity currents, likely hyperpycnal flows. Paleotransport measurements consistently indicate transport from the North European Platform located to the north of the basin.

Co-occurring coarse-grained facies, medium-bedded sandstones and lenticular conglomeratic filling of meandering channels show contrasting paleotransport directions from the Silesian Ridge, a structural high located on the SW flank of the basin. Their northward thinning across sections confirms a secondary source forming terminal channel deposits, that interfingered with the dominant North European Platform-derived distal gravity flows.

These findings reveal complex sediment routing in a late-rift stage basin, where distal gravity flows interact with episodic input by channels from interbasinal high, shaping hybrid slope-to-basin-floor deposition.