A record of the Holocene
Along the Atlantic coast of Argentina lies a record of the past. The archaeological site known as Monte Hermoso I contains human footprints preserved in stone, dated to approximately 7,000 years ago. These are detailed ichnites, but detailed ichnites—fossilized tracks—left by a group of Homo sapiens walking across a muddy tidal flat during the Holocene epoch.
The preservation is the result of a fortunate sequence of events. The tracks were made in soft, wet coastal sediments, likely a mix of clay and silt. Before they could be eroded by wind or water, they were gently buried by a subsequent layer of fine sandy sediment. Over millennia, groundwater percolated through these layers, depositing minerals that cemented the sediments into rock, turning the ephemeral prints into a permanent record. Radiocarbon dating of organic matter found within the sedimentary layers provides the 7,000-year-old age. The site is part of a larger protected area, the Pehuén Co - Monte Hermoso Provincial Nature Reserve, which contains a record of both human and animal tracks from different eras.
Reading the tracks
Analysis of the Monte Hermoso I trackways reveals a snapshot of daily life. The footprints belong to several individuals, including adults and children, suggesting a family or small social group moving together. In total, hundreds of human footprints have been identified at the site. The direction and spacing of the tracks indicate a walking pace consistent with searching for resources along the shoreline.
The environmental context, reconstructed from the geology and associated fossils, points to a coastal lagoon or intertidal zone. This setting, combined with the behavior inferred from the tracks, strongly suggests the group was foraging. They were likely searching for shellfish, crustaceans, and other marine resources exposed at low tide. This interpretation is supported by the presence of fossilized tracks of shorebirds, like the flightless Rhea, in the same geological layers. Nearby archaeological sites from the same period, such as "Las Ollas," further confirm that early Holocene people in this region had a diet that included marine resources. The discovery and study of the footprints are primarily associated with Argentine paleontologists, including Dr. Teresa Manera, who has worked extensively on the fossil tracks in the region.