Palaeoenvironmental conditions for the preservation of organic matter during the late Hauterivian in the Neuquén Basin (Western Argentina)
Registro en:
Omarini, J., Lescano, M. Odino-Barreto, A., Campetella, D., Tunik, M., Garbán, G., Brea, F., Erra, G., Aguirre-Urreta, B., Martinez, M., (2020). Palaeoenvironmental conditions for the preservation of organic matter during the late Hauterivian in the Neuquén Basin (Western Argentina). Marine and Petroleum Geology; 120; 104469.
0264-8172
Autor
Omarini Fernández, Julieta
Lescano, Marina
Odino Barreto, Andrea Lorena
Campetella, Débora Mical
Tunik, Maísa Andrea
Garbán, Grony
Brea, Fabián
Erra, Georgina
Aguirre Urreta, Beatriz
Martinez, Mathieu
Institución
Resumen
Fil: Omarini, Julieta. Universidad Nacional de Río Negro. Instituto de Investigación en Paleobiología y Geología. Río Negro, Argentina. Fil: Lescano, Marina. Instituto de Estudios Andinos Don Pablo Groeber (CONICET-UBA); Argentina. Fil: Odino Barreto, Andrea Lorena. Centro de Investigaciones Geológicas (CONICET-UNLP); Argentina. Fil: Campetella, Débora. Universidad Nacional de Río Negro. Instituto de Investigación en Paleobiología y Geología. Río Negro, Argentina. Fil: Tunik, Maísa. Universidad Nacional de Río Negro. Instituto de Investigación en Paleobiología y Geología. Río Negro, Argentina. Fil: Garbán, Grony. Centro de Investigaciones Geológicas (CONICET-UNLP), DTP Laboratorios SRL; Argentina. Fil: Brea, Fabián. Y-TEC (YPF Tecnología); Argentina. Fil: Erra, Georgina. Y-TEC (YPF Tecnología); Argentina. Fil: Aguirre Urreta, Beatriz. Instituto de Estudios Andinos Don Pablo Groeber (CONICET-UBA); Argentina. Fil: Martinez, Mathieu. Univ Rennes, CNRS, Géosciences Rennes - UMR 6118; Francia. The Agua de la Mula Member of the Agrio Formation, comprises marine deposits accumulated in a mixed
carbonate-siliciclastic outer ramp during the late Hauterivian. An innovative multi-proxy study that includes
sedimentological, geochemical and paleobiological data from the El Portón section were combined in order to
constrain the environmental context. Two major sedimentary cycles have been recognised (TST-HST) reflecting the position of both distal and proximal sediments within the depositional system. The distal outer ramp deposits (FA1) are predominantly characterised by carbonate-bearing mudstones, with TOC content up to 4.43 wt% TOC (average 1.62 wt%) and Type II marine-derived amorphous organic matter. The high TOC could be reflecting enhanced bioproductivity during periods of decreased salinity as mirrored by peaks of Micrantholithus, and reduced dilution by siliciclastic material in a distal setting. Conversely, the proximal outer ramp succession (FA2) shows a higher siliciclastic pattern, along with the terrestrial organic matter signal (Type II-III kerogen) and TOC content around 1 wt%(average 1.05 wt%). In this interval primary production is associated with more stable conditions and stratified water, as reflected in peaks of Nannoconus. These conditions allowed a greater diversity and high abundances of calcareous nannofossil assemblages. true -