The dawn of the Anthropocene imprinted in soil

The Anthropocene is not yet recognized in the official geologic timescale, and a key challenge lies in identifying a definitive stratigraphic marker for its onset. Although evidence of atmospheric changes preserved in ice cores and plutonium fallout in lake sediments has been proposed in this regard, their suitability remains contentious.We propose anthropogenic soils—soils bearing a major imprint of human activities—as a definitive marker for the Anthropocene. These soils exhibit distinct characteristics, including diagnostic horizons, human-induced mineralogical alterations, and the presence of artifacts, which provide unequivocal evidence of significant anthropogenic interventions in the environment, such as agriculture, urbanization, and waste management. Despite their susceptibility to erosion and other disturbances, anthropogenic soils offer a more resistant and comprehensive record than other proposed markers for the Anthropocene's onset. Their potential longevity, demonstrated by the preservation of paleosols over geologic timescales, underscores their reliability as a stratigraphic reference point.Critics argue that the diachronic nature of anthropogenic soils—the variability in the timing of their formation—presents a limitation. However, such age discrepancies are much smaller than the uncertainties associated with transitions between several pairs of geologic epochs, and are therefore justifiable. Furthermore, soil-unrelated auxiliary stratotypes could enhance and support the selected soil marker.Understanding the emergence of the Anthropocene necessitates an interdisciplinary approach, integrating stratigraphy with historical and documentary records to capture humanity's unprecedented role as a geologic force. Recognizing anthropogenic soils as a “golden spike” would position them as enduring testifiers to a transformative epoch—one that humanity still has the power to shape.