THE "STONES OF FIRE" IN THE PIAUÍ STATE

Abstract

The Pedra de Fogo Formation constitutes a sedimentary unit of the Parnaíba Basin, and in Brazil, it is considered one of the most important sedimentary records of the early Permian (298-273 million years ago). The Pedra de Fogo Formation lodge white colored stone fragments, generally dispersed within
the red loam that covers much of the region of Teresina and its neighborhood . One of the characteristics of these white stones is their ability to generate sparks of fire when placed in intense friction against each other. Other common characteristics are its high hardness, and its thermal capacity to heat up quickly and intensely under the blazing sun of Piauí. These "fire stones" began to form more than two hundred million years ago, when the Piauí State was part of the supercontinent Pangea, and consisted of a landscape formed by a set of shallow lakes with saline plains, sporadically fed by small intermittent drainages that were often kept dry, and were bordered by ledges formed by leafy ferns and small to large gymnorperms. In this landscape, also proliferated various species of animals, both terrestrial and aquatic. Through intense scientific research carried out in the states of Tocantins, Maranhão and mainly Piauí, both by the authors and other resea rchers, over many years, this work shows the main geological characteristics, within the paleoclimatic and paleogeographic context that led to the formation from the lithostratigraphic unit called Pedra de Fogo,
whence come the “fire-producing stones”.