Integrated bio- and lithofacies analysis of coarse-grained, tide-dominated deltaic environments across the Cretaceous/Paleogene boundary in Patagonia, Argentina
Four facies associations representing, from sea to land, namely (1) tidal bars in distal delta front, (2) proximal tidal bar complexes, (3) tidal channel and tidal flat deposits, and (4) multi-episodic, tide-influenced channels, resulted from the bio- and lithofacies analysis of the siliciclastic Cr...
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01956671_v36_n_p37_Scasso http://hdl.handle.net/20.500.12110/paper_01956671_v36_n_p37_Scasso |
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paper:paper_01956671_v36_n_p37_Scasso2023-06-08T15:20:15Z Integrated bio- and lithofacies analysis of coarse-grained, tide-dominated deltaic environments across the Cretaceous/Paleogene boundary in Patagonia, Argentina Scasso, Roberto Adrian Medina, Francisco Alberto Biofacies K/Pg Lithofacies Patagonia Salinity Tide-dominated delta biofacies Cretaceous delta environmental factor fauna lithofacies Paleogene salinity taxonomy tidal channel tidal flat trophic structure Argentina Patagonia Bivalvia Four facies associations representing, from sea to land, namely (1) tidal bars in distal delta front, (2) proximal tidal bar complexes, (3) tidal channel and tidal flat deposits, and (4) multi-episodic, tide-influenced channels, resulted from the bio- and lithofacies analysis of the siliciclastic Cretaceous/Paleogene Lefipán Formation (Patagonia, Argentina). Lithofacies analysis indicates the existence of coarse-grained, tide-dominated deltas fed with sediments of braided rivers, a rare type of delta that was developed at the western margin of a large marine embayment during the Cretaceous/Paleogene (K/Pg) boundary interval. Differences in taxonomic composition and ecological structure of the biofacies revealed variations in environmental factors, with salinity exerting the principal influence on biofacies. Salinity varied from oligohaline and mesohaline in the deltaic, high-stress environments, as typified by monospecific bivalve assemblages, to diverse and trophically more complex associations, indicating more normal marine and stable conditions. Thus, the biofacies provided an independent tool to check the results of the lithofacies analysis in complex transitional environments. A comparison of Maastrichtian and Danian faunas suggests that the K/Pg boundary event disrupted the stable Maastrichtian communities via the extinction of dominating species, leading to less diverse but more varied Danian assemblages. A shift in trophic structure to increased percentages of deposit-feeders in the Danian was not a direct consequence of impact-related environmental perturbations at the boundary in the studied onshore environment. This contrasts with previous studies of siliciclastic offshore settings, where such a shift in trophic composition was interpreted as the consequence of a productivity crisis at the boundary. © 2012 Elsevier Ltd. Fil:Scasso, R.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Medina, F.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2012 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01956671_v36_n_p37_Scasso http://hdl.handle.net/20.500.12110/paper_01956671_v36_n_p37_Scasso |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Biofacies K/Pg Lithofacies Patagonia Salinity Tide-dominated delta biofacies Cretaceous delta environmental factor fauna lithofacies Paleogene salinity taxonomy tidal channel tidal flat trophic structure Argentina Patagonia Bivalvia |
| spellingShingle |
Biofacies K/Pg Lithofacies Patagonia Salinity Tide-dominated delta biofacies Cretaceous delta environmental factor fauna lithofacies Paleogene salinity taxonomy tidal channel tidal flat trophic structure Argentina Patagonia Bivalvia Scasso, Roberto Adrian Medina, Francisco Alberto Integrated bio- and lithofacies analysis of coarse-grained, tide-dominated deltaic environments across the Cretaceous/Paleogene boundary in Patagonia, Argentina |
| topic_facet |
Biofacies K/Pg Lithofacies Patagonia Salinity Tide-dominated delta biofacies Cretaceous delta environmental factor fauna lithofacies Paleogene salinity taxonomy tidal channel tidal flat trophic structure Argentina Patagonia Bivalvia |
| description |
Four facies associations representing, from sea to land, namely (1) tidal bars in distal delta front, (2) proximal tidal bar complexes, (3) tidal channel and tidal flat deposits, and (4) multi-episodic, tide-influenced channels, resulted from the bio- and lithofacies analysis of the siliciclastic Cretaceous/Paleogene Lefipán Formation (Patagonia, Argentina). Lithofacies analysis indicates the existence of coarse-grained, tide-dominated deltas fed with sediments of braided rivers, a rare type of delta that was developed at the western margin of a large marine embayment during the Cretaceous/Paleogene (K/Pg) boundary interval. Differences in taxonomic composition and ecological structure of the biofacies revealed variations in environmental factors, with salinity exerting the principal influence on biofacies. Salinity varied from oligohaline and mesohaline in the deltaic, high-stress environments, as typified by monospecific bivalve assemblages, to diverse and trophically more complex associations, indicating more normal marine and stable conditions. Thus, the biofacies provided an independent tool to check the results of the lithofacies analysis in complex transitional environments. A comparison of Maastrichtian and Danian faunas suggests that the K/Pg boundary event disrupted the stable Maastrichtian communities via the extinction of dominating species, leading to less diverse but more varied Danian assemblages. A shift in trophic structure to increased percentages of deposit-feeders in the Danian was not a direct consequence of impact-related environmental perturbations at the boundary in the studied onshore environment. This contrasts with previous studies of siliciclastic offshore settings, where such a shift in trophic composition was interpreted as the consequence of a productivity crisis at the boundary. © 2012 Elsevier Ltd. |
| author |
Scasso, Roberto Adrian Medina, Francisco Alberto |
| author_facet |
Scasso, Roberto Adrian Medina, Francisco Alberto |
| author_sort |
Scasso, Roberto Adrian |
| title |
Integrated bio- and lithofacies analysis of coarse-grained, tide-dominated deltaic environments across the Cretaceous/Paleogene boundary in Patagonia, Argentina |
| title_short |
Integrated bio- and lithofacies analysis of coarse-grained, tide-dominated deltaic environments across the Cretaceous/Paleogene boundary in Patagonia, Argentina |
| title_full |
Integrated bio- and lithofacies analysis of coarse-grained, tide-dominated deltaic environments across the Cretaceous/Paleogene boundary in Patagonia, Argentina |
| title_fullStr |
Integrated bio- and lithofacies analysis of coarse-grained, tide-dominated deltaic environments across the Cretaceous/Paleogene boundary in Patagonia, Argentina |
| title_full_unstemmed |
Integrated bio- and lithofacies analysis of coarse-grained, tide-dominated deltaic environments across the Cretaceous/Paleogene boundary in Patagonia, Argentina |
| title_sort |
integrated bio- and lithofacies analysis of coarse-grained, tide-dominated deltaic environments across the cretaceous/paleogene boundary in patagonia, argentina |
| publishDate |
2012 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01956671_v36_n_p37_Scasso http://hdl.handle.net/20.500.12110/paper_01956671_v36_n_p37_Scasso |
| work_keys_str_mv |
AT scassorobertoadrian integratedbioandlithofaciesanalysisofcoarsegrainedtidedominateddeltaicenvironmentsacrossthecretaceouspaleogeneboundaryinpatagoniaargentina AT medinafranciscoalberto integratedbioandlithofaciesanalysisofcoarsegrainedtidedominateddeltaicenvironmentsacrossthecretaceouspaleogeneboundaryinpatagoniaargentina |
| _version_ |
1768546537680404480 |