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Université de Neuchâtel

Phosphorus and the roles of productivity and nutrient recycling during oceanic anoxic event 2

Mort, Haydon P. ; Adatte, Thierry ; Föllmi, Karl B. ; Keller, Gerta ; Steinmann, Philipp ; Matera, Virginie ; Berner, Zsolt ; Stüben, Doris

In: Geology, 2007, vol. 35, no. 6, p. 483-486

Four sections documenting the impact of the late Cenomanian oceanic anoxic event (OAE 2) were studied in basins with different paleoenvironmental regimes. Accumulation rates of phosphorus (P) bound to iron, organic matter, and authigenic phosphate are shown to rise and arrive at a distinct maximum at the onset of OAE 2, with an associated increase in δ13C values. Accumulation rates of...

Université de Neuchâtel

Phosphogenesis and organic-carbon preservation in the Miocene Monterey Formation at Naples Beach, California—The Monterey hypothesis revisited

Föllmi, Karl B. ; Badertscher, Christophe ; de Kaenel, Eric ; Stille, Peter ; John, Cédric M. ; Adatte, Thierry ; Steinmann, Philipp

In: GSA Bulletin, 2005, vol. 117, no. 5-6, p. 589-619

The middle part of the Miocene Monterey Formation at Naples Beach, west of Santa Barbara, California, is predominantly composed of organic-rich mudstone interstratified with phosphatic laminae. Minor lithologies include volcanic ash, dolomite, porcelanite and chert, and condensed phosphatic beds. Sediments dated as 14.3–13.5 Ma have average total organic carbon (TOC) values around 8.5 wt%, and...

Université de Neuchâtel

Carbonaceous and Phosphate-Rich Sediments of the Miocene Monterey Formation at El Capitan State Beach, California, U.S.A.

John, Cédric M. ; Föllmi, Karl B. ; De Kaenel, Eric ; Adatte, Thierry ; Steinmann, Philipp ; Badertscher, Christophe

In: Journal of Sedimentary Research, 2002, vol. 72, no. 2, p. 252-267

The organic- and phosphate-rich interval of the Monterey Formation at El Capitan State Beach (west of Santa Barbara, California, U.S.A.; late early to early late Miocene in age) is composed of a carbonaceous marl (TOC contents between 1.2 and 23.2 wt %) with intercalated phosphate-rich laminae, lenses, and layers. Subordinate lithologies include ash layers, dolomitized horizons, and siliceous...

Université de Neuchâtel

Speciation of naturally-accumulated uranium in an organic-rich soil of an alpine region (Switzerland)

Regenspurg, Simona ; Margot-Roquier, Camille ; Harfouche, Messaoud ; Froidevaux, Pascal ; Steinmann, Philipp ; Junier, Pilar ; Bernier-Latmani, Rizlan

In: Geochimica et Cosmochimica Acta, 2010, vol. 74, no. 7, p. 2082–2098

Very high concentrations of uranium (up to 4000 ppm) were found in a natural soil in the Dischma valley, an alpine region in the Grisons canton in Switzerland. The goal of this study was to examine the redox state and the nature of uranium binding in the soil matrix in order to understand the accumulation mechanism. Pore water profiles collected from Dischma soil revealed the establishment of...

Université de Neuchâtel

Organic carbon deposition and phosphorus accumulation during Oceanic Anoxic Event 2 in Tarfaya, Morocco

Mort, Haydon P. ; Adatte, Thierry ; Keller, Gerta ; Bartels, David ; Föllmi, Karl B. ; Steinmann, Philipp ; Berner, Zsolt ; Chellai, E.H.

In: Cretaceous Research, 2008, vol. 29, no. 5-6, p. 1008-1023

With a multi-proxy approach, an attempt was made to constrain productivity and bottom-water redox conditions and their effects on the phosphorus accumulation rate at the Mohammed Plage section on the Tarfaya coast, Morocco, during the Cenomanian-Turonian Anoxic Event (OAE 2). A distinct δ13Corg isotope excursion of +2.5‰ occurs close to the top of the section. The...

Université de Neuchâtel

A peat core based estimate of Late-glacial and Holocene methane emissions from northern peatlands

Steinmann, Philipp ; Huon, S. ; Roos-Barraclough, F. ; Föllmi, Karl B.

In: Global and Planetary Change, 2006, vol. 53, no. 4, p. 233-239

We estimate the intensity of Late-glacial and Holocene methane emissions from peatlands based on their paleo net primary production (PNPP). The PNPP is derived from the carbon accumulation rates of the studied bog profile (Etang de la Gruère, Switzerland), which are corrected for the degree of peat degradation. The obtained PNPP curve is taken as a proxy for methane emissions. It shows...

Université de Neuchâtel

Enrichment of redox-sensitive trace metals (U, V, Mo, As) associated with the late Hauterivian Faraoni oceanic anoxic event

Bodin, Stéphane ; Godet, Alexis ; Matera, Virginie ; Steinmann, Philipp ; Vermeulen, Jean ; Gardin, Silvia ; Adatte, Thierry ; Coccioni, Rodolfo ; Föllmi, Karl B.

In: International Journal of Earth Sciences, 2007, vol. 96, no. 2, p. 327-341

The Faraoni Level is a short-lived oxygen-deficient event that took place during the latest Hauterivian. In order to improve our understanding of the palaeoenvironmental conditions that occurred during this event, we have analysed the contents of several redox-sensitive trace elements (U, V, Mo, As, Co, Cd, Cu, Zn, Ni, Pb, Cr) from bulk limestone samples of late Hauterivian–early Barremian age...