Abstract Despite creating one of Earth's most iconic landforms, and having been studied since antiquity, river meandering is currently explained by several alternative models that remain debated. This is partly because observers have deconstructed meanders to a set of properties thought to be fundamental or significant for meandering, but each of these underpinning properties is itself complex and in turn requires analysis of its causes and mechanisms. This philosophical contribution aims to provide a perspective on the state of the science that makes a rigorous interrogation into what ‘causation’ actually means, and explores what a systems perspective can elucidate about meandering phenomena. We approach the problem through a discussion of the variety of ways in which previous researchers have tackled the problem of meandering, from a channel and floodplain perspective, on Earth and Mars, in the field and laboratory, and at the present day through to the ancient stratigraphic record. It is evident that river meandering has numerous causal pathways rather than a single set of necessary and sufficient conditions. A systemic view on the evolution of plant species shows that their feedbacks on river pattern likewise have several pathways. Employing the conceptual apparatus of the philosophy of science will move us towards a more consensual synthesis of river meandering.

Abstract Fluvial point-bar deposits are described from the c. 1 Ga Diabaig Formation, representing some of the most compelling architectural evidence of planform sinuosity recognized in pre-vegetation sedimentary strata to date. The stratigraphical architecture of the deposits indicates different planform transformations in response to meander-bend expansion and downstream migration. Point-bar architectural motifs are locally abundant in the unit and this is attributed to elevated amounts of mud-calibre cohesive sediment. Mud afforded landscape stability that, together with limited stream power, was sufficient to corral sediment into single-thread, sinuous channels. Significant volumes of fine-grained sediment were encouraged to accumulate by the local basin setting of several topographically confined endorheic depressions. These conditions ceased once the hydrologically closed valleys were filled, with the overlying sandstone-dominated Applecross Formation subsequently deposited by low-sinuosity, braided rivers that bypassed fine-grained sediment oceanward. Other endorheic basins conducive to the formation of depositional meanders should be expected to have been relatively widespread on pre-vegetation Earth, though many individually limited in size, confined by their inherited topographies. Depositional architectures representative of sinuous channel planforms remain scarce within more extensive, externally drained basins.