Artículo
Lacustrine microbialite pinnacles in the Palaeogene of Patagonia, Argentina: Facies and controls
Alonso Zarza, Ana María; Cabaleri, Nora Graciela
; Huerta, Pedro; Armella, Claudia
; Rodríguez Berriguete, Álvaro; Monferran, Mateo Daniel
; Gallego, Oscar Florencio
; Ubaldon, María Cecilia; Silva Nieto, Diego Gonzalo
Fecha de publicación:
10/2020
Editorial:
Elsevier Science
Revista:
Sedimentary Geology
ISSN:
0037-0738
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Large carbonate microbialite build-ups are relatively uncommon in ancient fresh-water lacustrine basins as compared with those marine and saline environments. This paper discusses the formation of a large continental lacustrine deposit, the Oligocene-Miocene Carinao Formation in Argentina, which contains large bioherms. The lacustrine formation occurs in N-S corridor and is mostly composed by meter scale pinnacles and sheet-like carbonate beds that grade to detrital deposits towards the more subsident southern areas. The main facies are autochthonous and allochthonous limestones and detrital deposits. The autochthonous limestones include the carbonate pinnacles, which are about 4 m high and 0.5 m in diameter and coalesce laterally to form very continuous beds (several kms). The pinnacles are formed by plate-like, dome, vertically elongated and irregular horizontal bioherms, most of them with radial structure. The bioherms are boundstones of fibrous (fans and spherulites) and feather calcite crystals, micrite and inequigranular calcite mosaics. Both biogenic and abiogenic processes interfered in carbonate precipitation. Allochthonous limestones include peloidal, ostracod and intraclastic limestones, some containing coated grains. Polymictic conglomerates and cross-bedded hybrid arenites deposited in a fluvial-deltaic system located at the southwest of the basin. δ13C values vary between −0.4 and −3.2‰ VPDB and δ18O are comprised between −5.7 and −8.6‰ VPDB. The 87Sr/86Sr ratios range between 0.7061 and 0.7056. The Carinao Formation deposited in a fresh-water lake, sourced by meteoric and deep-groundwater. Tectonics was a main control determining the configuration of the lake system, the water supply and the alignment of some bioherms. The vertical succession or the different bioherms morphologies reflects well the lake level changes controlled by both tectonic and climate.
Palabras clave:
ARGENTINA
,
BIOHERMS
,
CARBONATE
,
GEOCHEMISTRY
,
LACUSTRINE
,
PINNACLES
Archivos asociados
Licencia
Identificadores
Colecciones
Articulos(CECOAL)
Articulos de CENTRO DE ECOLOGIA APLICADA DEL LITORAL (I)
Articulos de CENTRO DE ECOLOGIA APLICADA DEL LITORAL (I)
Articulos(INGEIS)
Articulos de INST.DE GEOCRONOLOGIA Y GEOLOGIA ISOTOPICA (I)
Articulos de INST.DE GEOCRONOLOGIA Y GEOLOGIA ISOTOPICA (I)
Citación
Alonso Zarza, Ana María; Cabaleri, Nora Graciela; Huerta, Pedro; Armella, Claudia; Rodríguez Berriguete, Álvaro; et al.; Lacustrine microbialite pinnacles in the Palaeogene of Patagonia, Argentina: Facies and controls; Elsevier Science; Sedimentary Geology; 408; 10-2020; 1-15
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