Dam-type tufas and travertine in the semi-arid climate of Ras Elma (South of Taza, Morocco): morphogenesis, tectonic control, and petrography

Lahrichi, Kamal , Fattasse, Hamid , Briouel, Radouane , Okacha, Abdelmonaim , Gartet, Jaouad , Quinif, Yves

2026-04-22 EURO-MEDITERRANEAN JOURNAL FOR ENVIRONMENTAL INTEGRATION 2026   11(卷), 5(期), (null页)

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The Ras Elma region, situated south of Taza, Morocco, hosts extensive barrage-type tufas along a steep talus between the caf & eacute;-restaurant and the large tufa cascade. These freshwater carbonate deposits display multi-level terraces and dam-like morphologies, resulting from the complex interplay of hydrodynamic, biological, and tectonic factors. This study examines their morphogenesis, sedimentary processes, and petrographic characteristics. Field observations indicate that tufa deposition is strongly controlled by slope breaks, flow velocity, and turbulence, which enhance CO2 degassing and promote calcite precipitation. Petrographic analyses reveal stromatolitic fabrics composed of micritic and sparitic laminae, frequently associated with encrusted plant remains and microbial mats, underscoring the critical role of biological activity in tufa development. The underlying substrate, consisting of highly fractured marls and limestones, suggests a significant tectonic influence on terrace formation, consistent with multi-generational deposition during the Late Pleistocene and Holocene. Overall, the Ras Elma tufas illustrate the intricate interactions among tectonics, hydrodynamics, water chemistry, and biotic processes, offering valuable insights into continental carbonate formation and their paleoenvironmental significance.