A story with millions of years
Vive Cabeceiras · Complexo geológico de Cabeceiras de Basto · datação citada no estudo

The rock age and landscape shape are not the same question.

The work of A. Almeida refers to a dating of the complex of Cabeceiras de Basto by the uranium-lead method, using the minerals zircon and monazite. The result cited is a minimum age of 311 ± 1 million years. It is a geological reference to the rock formation studied: it does not date the construction of a wall, nor does it establish when a slope has acquired the form that we see today. The article integrates the minutes of the V National Congress of Geology, published in 1998. Upon reaching the value, Almeida refers to a work of geochronology with other authors, indicated in the bibliography. This chain of references allows us to understand where the number comes from: it is a result of research, not an age estimated by color or by the size of the grains. Reading a landscape requires separating time scales. One thing is the age attributed to the rocky complex; another, the transformation of relief; another, the moment when a stone was used in a construction. The three stories can cross the same wall, but they need different evidence.

Sources and context
A. Almeida (1998) — Metallurgical specialisation of the peraluminous granites of two micas of the Cabeceiras de Basto complex, IGM 84(1), B-79–B-82; p. 325 of the PDF
https://eu-central-1.linodeobjects.com/socgeol-files/production/documents/168/original.pdf?1651938546=#page=325
Accessed: 2026-11-07

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