The technological dichotomy under debate: The chaînes opératoires of copper metallurgy in the third millennium BC in the Upper Guadalquivir (southern Spain)

• The interpretation of prehistoric copper metallurgy (late 4th-3rd millennium BC) in the Iberian Peninsula has historically been dominated by a traditional paradigm. • Archaeometallurgical analysis of copper products recovered from three key sites in the southern Spain has refuted this paradigm. • Analytical protocol that integrates metallographic microscopy, electron probe microanalysis (EPMA) and Vickers microhardness tests allow us reconstruct the chaînes opératoires of manufacturing. • Prehistoric metallurgy is more complex, it is shaped by a diversity of models represented both by specialised settlements and by domestic-scale production units. • We must reconsider models of craft specialisation and standardisation, knowledge transmission and social interaction networks in prehistoric times. The interpretation of metallurgy in the so-called Chalcolithic period (late 4th-3rd millennium BC) in the Iberian Peninsula has historically been dominated by a paradigm that attributed to its southern region a secondary, dependent role and an inability that defined it as a simple system with a low degree of specialisation, low production capacity and reduced demand for metals. At the technological level, this model was defined by metallurgical knowledge whose domestic application slowed down its sophistication of its methods and resulted in typological monotony and the continuity, for centuries, of the chaînes opératoires of manufacturing. This led to the postulation of a profound dichotomy between the south-eastern and south-western regions. This article presents a direct refutation of this model through the archaeometallurgical analysis of a corpus of 30 copper products dating from the third millennium BC, recovered from three key sites in the Upper Guadalquivir: Marroquíes Bajos, Las Eras del Alcázar and Castro del Río. By applying an analytical protocol that integrates metallographic microscopy, electron probe microanalysis (EPMA) and Vickers microhardness tests , the operational chain implemented is reconstructed. The results reveal remarkable technological consistency and a total absence of simple manufacturing sequences (smelting and forging). On the contrary, the systematic mastery of complex production processes is evident, with a combination of forging and annealing cycles, representing 100% of the sample. This suggests a sophisticated technological tradition shared throughout the southern peninsula, which forces us to reconsider models of craft specialisation, knowledge transmission and social interaction networks in this period.