ringsand

Ringsand is a descriptive term used in sedimentology to refer to a texture in which sandy grains form concentric, ring-like bands around a central core. The pattern can produce visible circular or ovoid rings in outcrops or freshly exposed surfaces and may resemble a target or archipelago of rings. Because ringsand is not universally standardized, its exact definition and diagnostic criteria can vary among researchers.

Formation of ringsand is attributed to environmental flows that repeatedly deposit sediment in circular patterns around an obstacle or center. In aqueous settings, recirculating eddies, paleochannels, or the presence of a submerged core such as a woody root or rock can create conditions where sediment is deposited in successive rings as flows decelerate and shift direction. In aeolian (wind-driven) environments, circular airflow around central features or localized depressions can similarly concentrate grains into ringed textures. Over time, successive depositional events may preserve multiple rings with varying grain sizes and compositions.

Ringsand occurrences have been reported in a range of settings, including coastal wetlands, lake shores, and desert playas. They are typically small-scale features that can be overlooked or mistaken for other ringed textures such as ripple marks or dune cross-bedding. Proper identification relies on careful field observation, grain-size analysis, and, when possible, thin-section examination to distinguish concentric rings from other sedimentary textures.

The term ringsand emphasizes pattern and morphology rather than a specific mineralogy or depositional process, and it may appear in field guides, academic papers, or descriptive reports with varying definitions.