Relating Grain‐Scale Mechanics to Fluvial Energy Heterogeneity: Quartz Microtextural Signatures in the Kinu River, Japan

Abstract

Quartz grain surface microtextures serve as robust records of sedimentary history and depositional environment, yet a coherent framework quantitatively linking specific microtextures to stream power remains underexplored. This study integrates scanning electron microscopy (SEM) with quantitative hydrodynamic analysis along the Kinu River, Japan, to elucidate the sensitivity of quartz microtextures to unit stream power ( ω ). Analysis reveals that microtexture frequencies vary distinctly along the river, yet correlations with unit stream power ( ω ) are insignificant at the overall catchment scale. However, within low‐gradient reaches ( S  < 0.001), we identified a strong positive correlation between unit stream power ( ω ) and the frequency of crescentic percussion marks. As crescentic percussion marks require high‐magnitude impacts to fracture the crystal lattice, they function as sensitive, high‐threshold indicators of local collisional energy. In contrast, chemical microtextures show no significant relationship with the unit stream power ( ω ) in the Kinu River data set, consistent with previous interpretations that they primarily reflect cumulative residence in low‐energy or organic‐rich zones rather than instantaneous flow intensity. Furthermore, comparative analysis between a channel deposit and an adjacent dune deposit formed directly by wind action suggests that warm‐humid riverine dunes can retain strong microtextural inheritance from their fluvial source, distinguishable mainly by incipient aeolian overprinting (e.g., bulbous edges and flat cleavage surfaces). Ultimately, building upon qualitative discrimination, this study establishes a framework relating grain‐scale surface microtextures to fluvial energy heterogeneity.