78823 20230914083222.0 doi 10.1186/s42501-019-0021-y sideral 111146 ART-2019-111146 eng Arenas, C. Universidad de Zaragoza (orcid)0000-0002-4212-0524 Coupling textural and stable-isotope variations in fluvial stromatolites: Comparison of Pleistocene and recent records in NE Spain 2019 Access copy available to the general public Unrestricted Textural and stable isotopic features of two middle Pleistocene fluvial stromatolite profiles are compared to a recent stromatolite, both formed in the River Piedra system (NE Spain), to test the reliability of climatic, hydrologic and depositional information derived from ancient records. The Pleistocene stromatolites formed in a multi-domed, highly-inclined cascade-barrage. The recent stromatolite also formed in a highly-inclined cascade of the River Piedra, the sedimentary conditions of which were periodically examined between the years 2000 and 2012. The Pleistocene stromatolites are formed of an alternation of 1) thin large-crystal laminae (type A), with elongated crystals up to 1 mm long, and 2) thick small-crystal laminae (type B), consisting of cyanobacterial fan- and bush-shaped bodies. The textural and isotopic comparison with the recent stromatolite shows that each A–B couplet corresponds to one year. The type-A laminae are comparable to the macrocrystalline laminae that occur in the cool-period deposits of the recent stromatolite, and the type-B laminae are comparable to the warm-period deposits of the recent stromatolite. Water temperatures (Tw), calculated from d 18 O calcite and present measures of d 18 O water , were similar in the Pleistocene and recent specimens, and close to the measured river Tw. Thus, the Pleistocene stromatolites formed not far from isotopic equilibrium, as did the recent stromatolite. The Pleistocene d 18 O calcite biannual oscillation is wider in amplitude than in the recent stromatolite, which suggests larger differences in Tw through the year in the Pleistocene than at present. The Pleistocene d 13 C calcite does not show any pattern; and the values are slightly higher than the recent ones. The co-evolution of d 18 O and d 13 C is parallel in the Pleistocene stromatolites, matching the recent stromatolite behavior. These results and their comparison with other ancient examples prove that textural and isotopic features in ancient stromatolites are useful tools to infer past depositional, climatic and hydrological conditions. Moreover, interpretations from recent fluvial stromatolites can be extrapolated to past environments to help decipher patterns of past processes, in cases where both recent and ancient stromatolites can be compared within one environmental setting. Such comparisons may be used to help interpretations of ancient stromatolites where the modern ones are not available to study. info:eu-repo/grantAgreement/ES/DGA/E32-17R info:eu-repo/grantAgreement/ES/MICINN/CGL2013-42867 info:eu-repo/grantAgreement/ES/MINECO/CGL2009-09216-CLI info:eu-repo/semantics/openAccess by http://creativecommons.org/licenses/by/3.0/es/ 2.02 2019 PALEONTOLOGY 15 / 55 = 0.273 2019 Q2 T1 GEOSCIENCES, MULTIDISCIPLINARY 111 / 198 = 0.561 2019 Q3 T2 0.68 2019 Geography, Planning and Development 2019 Q1 Paleontology 2019 Q2 Earth-Surface Processes 2019 Q2 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Osácar, M.C. Universidad de Zaragoza (orcid)0000-0002-5246-366X Auqué, L. Universidad de Zaragoza (orcid)0000-0003-1463-1682 Sancho, C. Universidad de Zaragoza (orcid)0000-0002-1304-2264 2000 685 Universidad de Zaragoza Dpto. Ciencias de la Tierra Área Petrología y Geoquímica 2000 427 Universidad de Zaragoza Dpto. Ciencias de la Tierra Área Geodinámica Externa 2000 280 Universidad de Zaragoza Dpto. Ciencias de la Tierra Área Estratigrafía 2000 120 Universidad de Zaragoza Dpto. Ciencias de la Tierra Área Cristalografía Mineralog. 8, 1 (2019), 13 [20 pp] J. Palaeogeogr. Journal of Palaeogeography-English 2095-3836 1894774 http://zaguan.unizar.es/record/78823/files/texto_completo.pdf Versión publicada 87909 http://zaguan.unizar.es/record/78823/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:78823 articulos driver 2023-09-13-10:40:46 ARTICLE