Journal articles
Palaeoenvironmental conditions for the preservation of organic matter during the late Hauterivian in the Neuquén Basin (Western Argentina)
Abstract : The Agua de la Mula Member of the Agrio Formation in the Neuquén Basin, 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 most distal and proximal sediments in 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 nannofossils assemblages.
Cited literature [120 references]
https://hal-insu.archives-ouvertes.fr/insu-02863256
Contributor : Isabelle Dubigeon <>
Submitted on : Wednesday, June 10, 2020 - 9:29:30 AM
Last modification on : Wednesday, January 20, 2021 - 11:46:21 AM
Contributor : Isabelle Dubigeon <>
Submitted on : Wednesday, June 10, 2020 - 9:29:30 AM
Last modification on : Wednesday, January 20, 2021 - 11:46:21 AM
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