Quaternary tufas of the Inglares River valley : an example of changing slope stepped fluvial system, Álava, N Spain
Larena, Zuriñe (Universidad del País Vasco)
Arenas Abad, Concepción (Universidad de Zaragoza)
Ortiz, José Eugenio (Universidad Politécnica de Madrid)
Sanjuan, Josep (Universitat de Barcelona)
Pascual, Ana (Universidad del País Vasco)
Larraz, Mariano (Universidad de Navarra)
Murelaga, Xabier (Universidad del País Vasco)
Baceta Caballero, Juan Ignacio (Universidad del País Vasco)

Data:	2025
Resum:	This work discusses the factors that controlled the formation of Quaternary tufa deposits along the valley of Inglares River, currently fed by a karst-carbonate aquifer, Álava, north Spain. It is based on stratigraphic, chronological (amino-acid racemization, AAR), sedimentological and d13C and d18O analyses, complemented with paleontology. The examined deposits occur as isolated bodies at the uppermost and downmost stretches of the present valley, reaching 45 and 25 m thick, respectively. AAR dating set them in two groups: Middle-Late Pleistocene (MIS 5e) and Middle and Late Holocene (MIS 1). The former only occurs in the downstream stretch. Up to eleven carbonate facies and minor allocththonous coarse-detrital facies have been characterised and arranged into four distinct facies associations. Their features and bedding geometry suggest two main depositional settings. A low- to slightly moderate-slope, stepped stretch with small barrage-cascades, dammed areas, and abundant palustrine facies (downstream system and a high-slope stretch with steep stepped cascades and pools (upstream system). These settings respond to bedrock lithology and structure changes through the valley, which appear to be principal factors controlling the tufa depositional architecture. Based on d13C, an increase in aridity in inferred from the Middle-Late Pleistocene to the Holocene. The isotopic differences between the upstream and downstrem Holocene tufa might reflect the spatial evolution of d13C and d18O of stream water through the ca 8-km long surveyed transect. Erosion by sudden changes in water discharge might have caused the stratigraphic gap between the two tufa groups.
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Fluvial tufa ; Sedimentology ; Facies model ; Quaternary climate ; North iberia
Publicat a:	Geologica acta, Vol. 23 (2025) (Articles) , ISSN 1696-5728

Adreça original: https://revistes.ub.edu/index.php/GEOACTA/article/view/47435
Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/10000001422
DOI: 10.1344/GeologicaActa2025.23.10

33 p, 16.0 MB

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