Proteomic profiling of cellular steatosis with concomitant oxidative stress in vitro

10.1186/s12944-016-0283-7Lipids in Health and Disease15111

A NEW FE-CARBONATE FORMATION WINDOW ON MARS

International audienceIn this study, we focus on modeling results based on a kinetic weathering experimental setup under Mars-like conditions. With these models, we aim to enhance our ability to interpret the redox and hydrological conditions when finding Fe-oxides or carbonates on Mars. We determined a new Fe-carbonate formation window, even under oxidizing conditions from a thermodynamic standpoint, redefining the significance of “reducing” or “oxidizing” conditions on Mars. Additionally, because of the different residence time required to form Fe-oxides and Fe-carbonate, we interpret that Fe-carbonate would be primarily a clue for a different hydrological regime (chemical sedimentation or higher weathering rates) and only then a redox marker. At a global scale, the formation of authigenic siderite and even other carbonates (for example, when accounting the Mg-inhibition of calcite precipitation) during rock weathering would be rather limited without long residence times or later evaporation

A NEW FE-CARBONATE FORMATION WINDOW ON MARS

International audienceIn this study, we focus on modeling results based on a kinetic weathering experimental setup under Mars-like conditions. With these models, we aim to enhance our ability to interpret the redox and hydrological conditions when finding Fe-oxides or carbonates on Mars. We determined a new Fe-carbonate formation window, even under oxidizing conditions from a thermodynamic standpoint, redefining the significance of “reducing” or “oxidizing” conditions on Mars. Additionally, because of the different residence time required to form Fe-oxides and Fe-carbonate, we interpret that Fe-carbonate would be primarily a clue for a different hydrological regime (chemical sedimentation or higher weathering rates) and only then a redox marker. At a global scale, the formation of authigenic siderite and even other carbonates (for example, when accounting the Mg-inhibition of calcite precipitation) during rock weathering would be rather limited without long residence times or later evaporation

Pressure-temperature conditions and significance of Upper Devonian eclogite and amphibolite facies metamorphisms in southern French Massif central

The southwestern French Massif central in western Rouergue displays an inverted metamorphic sequence with eclogite and amphibolite facies units forming the top of the nappe stack. They are often grouped into the leptyno-amphibolite complex included, in this area, at the base of the Upper Gneiss Unit. We sampled garnet micaschists and amphibolites to investigate their metamorphic history with isochemical phase diagrams, thermobarometry and U-Pb zircon dating. Our results demonstrate that two different tectono-metamorphic units can be distinguished. The Najac unit consists of biotite-poor phengite-garnet micaschists, a basic-ultrabasic intrusion containing retrogressed eclogites and phengite orthogneisses. Pressure and temperature estimates on micaschists with syn-kinematic garnets yield a prograde with garnet growth starting at 380 °C/6–7 kbar, peak pressure at 16 kbar for 570 °C, followed by retrogression in the greenschist facies. The age of high pressure metamorphism has been constrained in a recent publication between ca. 383 and 369 Ma. The Laguépie unit comprises garnet-free and garnet-bearing amphibolites with isolated lenses, veins or dykes of leucotonalitic gneiss. Thermobarometry and phase diagram calculation on a garnet amphibolite yield suprasolidus peak P-T conditions at 710 °C, 10 kbar followed by retrogression and deformation under greenschist and amphibolite facies conditions. New U-Pb analyses obtained on igneous zircon rims from a leucotonalitic gneiss yield an age of 363 ± 3 Ma, interpreted as the timing of zircon crystallization after incipient partial melting of the host amphibolite. The eclogitic Najac unit records the subduction of a continental margin during Upper Devonian. It is tentatively correlated to a Middle Allochthon, sandwiched between the Lower Gneiss Unit and the Upper Gneiss Unit. Such an intermediate unit is still poorly defined in the French Massif central but it can be a lateral equivalent of the Groix blueschists in the south Armorican massif. The Uppermost Devonian, amphibolite facies Laguépie unit correlates in terms of P-T-t evolution to the Upper Gneiss Unit in the Western French Massif central. This Late Devonian metamorphism is contemporaneous with active margin magmatism and confirms that the French Massif central belonged to the continental upper plate of an ocean-continent subduction system just before the stacking of Mississippian nappes