000126028 001__ 126028
000126028 005__ 20241125101154.0
000126028 0247_ $$2doi$$a10.1007/s41513-023-00207-9
000126028 0248_ $$2sideral$$a133476
000126028 037__ $$aART-2023-133476
000126028 041__ $$aeng
000126028 100__ $$aFernandes, João Paulo
000126028 245__ $$aQuaternary fluvial carbonate deposits of the Almonda River Valley, Central Portugal
000126028 260__ $$c2023
000126028 5060_ $$aAccess copy available to the general public$$fUnrestricted
000126028 5203_ $$aThis paper discusses the formation and preservation of a fluvial tufa system influenced by Atlantic climate based on stratigraphical, chronological (amino-acid racemization, AAR), sedimentological and stable-isotope analyses. On the southwestern Iberian Peninsula, the tufas and associated deposits of the Almonda River valley occur as isolated terraced bodies and reach 25 m thick. AAR dated most deposits to within the warm Marine Isotope Stage 5 (MIS-5). Two Holocene ages were reset within MIS-5 based on diverse criteria. Widely varied carbonate and minor allochthonous coarse detrital facies occur arranged in four simple vertical associations. The deposit geometry and facies association distribution correspond to a low- to moderate-sloped fluvial valley consisting of several short knickpoints and extensive flat areas between them. The latter are occupied by slow-flowing water facies (carbonate sand, lime mud, phytoclast and oncoid rudstones, and up-growing stem boundstones). Facies that formed in moderate- to high-slope substrates were stromatolite, moss and down-growing stem boundstones. The homogeneous Miocene bedrock lithology and gentle structural deformation propitiated this depositional architecture. Calcite δ13C and δ18O values suggest that the aquifer water provided the outflowing Almonda water with (1) 18O-enriched water, compared with present precipitation and groundwater δ18O values, and (2) 13C-depleted CO2 from bituminous rocks and vegetation cover in the catchment. The proximity to the Atlantic coast favoured the Mesozoic-rock aquifer recharge with 18O-enriched water precipitation, assuring water availability during the formation of the studied tufas. No evidence of frequent intense erosion phases might indicate stable precipitation regimes, which would have allowed the preservation of loose fine-grained and palustrine deposits.
000126028 536__ $$9info:eu-repo/grantAgreement/ES/MINECO/CGL2009-09216-BTE$$9info:eu-repo/grantAgreement/ES/MINECO/CGL2013-42867-P
000126028 540__ $$9info:eu-repo/semantics/openAccess$$aby$$uhttp://creativecommons.org/licenses/by/3.0/es/
000126028 590__ $$a1.3$$b2023
000126028 592__ $$a0.448$$b2023
000126028 591__ $$aGEOLOGY$$b22 / 61 = 0.361$$c2023$$dQ2$$eT2
000126028 593__ $$aStratigraphy$$c2023$$dQ2
000126028 593__ $$aGeology$$c2023$$dQ2
000126028 594__ $$a2.6$$b2023
000126028 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion
000126028 700__ $$0(orcid)0000-0002-4212-0524$$aArenas, Concha$$uUniversidad de Zaragoza
000126028 700__ $$aOrtiz, José Eugenio
000126028 7102_ $$12000$$2280$$aUniversidad de Zaragoza$$bDpto. Ciencias de la Tierra$$cÁrea Estratigrafía
000126028 773__ $$g49, 2 (2023), 133–167$$pJ. iber. geol.$$tJOURNAL OF IBERIAN GEOLOGY$$x1698-6180
000126028 8564_ $$s21216111$$uhttps://zaguan.unizar.es/record/126028/files/texto_completo.pdf$$yVersión publicada
000126028 8564_ $$s2001591$$uhttps://zaguan.unizar.es/record/126028/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada
000126028 909CO $$ooai:zaguan.unizar.es:126028$$particulos$$pdriver
000126028 951__ $$a2024-11-22-12:08:25
000126028 980__ $$aARTICLE