‘Invaluable’ Petroglyphs and Fossilized Footprints Found in Brazil’s ‘Dinosaur Valley’

A collection of petroglyphs formed in vast, geometric circles have been discovered in Brazil’s Serrote do Letreiro site. However, according to a study published by local archaeologists, the land had more secrets to reveal: the fossilized footsteps of Early Cretaceous creatures—of the two and four-legged reptilian type—trailing alongside the enigmatic abstractions. 

The Serrote do Letreiro site (meaning “Signpost Hill”) covers roughly 5,000 square meters inside the Vale dos Dinossauros Natural Monument, or Dinosaur Valley, in northeast Brazil. It has been known as a rich repository for ancient and primordial information for decades, with the earliest palaeontological study conducted in 1975. The Petroglyphs at Serrote do Letreiro were first documented by excavators in 1979, who called them “Cariri Indian carvings”.

But interest in the carvings seemingly waned, as the new study marks the first major breakthrough in the group. Experts have determined that a coarse instrument was used to carve circular figures containing radial lines on the stone surface. 

The study authors wrote: “Despite the profusion of identified petroglyphs, no overlap was observed between these inscriptions and the fossilized footprints. In none of the cases was it found that the creation of a petroglyph resulted in damage to the existing footprints, suggesting thoughtfulness by the makers.”

Archaeologists also concluded that the petroglyphs share “striking” motifs and were executed with comparable or identical techniques as previously known archaeological rock art in the states of Paraíba and Rio Grande do Norte. They suggested that the petroglyphs date from a period between 9400–2620 years BP (Before Present), based on radiocarbon dating of burials situated nearby.

“Further research utilizing new methods of direct dating of petroglyphs, such as X-ray fluorescence spectrometry, will certainly shed light on the chronology issue. In the absence of applying absolute dating methods to the petroglyphs, the proposed dating here remains restricted to iconographic inferences, as well as extrapolation from the temporal horizons identified in the few dated sites in the region,” wrote the study authors.