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The formation of carbonate build‐ups associated with seafloor methane vents – where microbially mediated sulphate‐dependent anaerobic oxidation of methane produces alkalinity – is well documented in modern marine environments and in the geologic record. However, the triggering event(s) behind the processes leading to hydrocarbon disequilibrium, seeping and consequent deposition of seep‐carbonates remain poorly constrained. This contribution characterises the salinity, geochemistry and temperature framework of a suit of fluid inclusions from hydrocarbon‐derived seep‐carbonate veins, collected from the Marmorito Formation in the Monferrato Hills, NW Italy. The datasets yield evidence of three different precipitation events, which comprise porous structures composed of well bladed calcites and aggregated spherules of aragonite. Fluid inclusions analysis shows the presence of a heterogeneous entrapment of immiscible fluids proving the paleo‐dissolution of a suite of complex hydrocarbons, which have a wide range of closing temperature starting at ca. 60°C. These physical and chemical conditions are considered to indicate seep‐carbonate deposition driven by disequilibrium of hydrocarbon‐bearing compounds at temperatures much warmer than the background ambient bottom waters (ca. 1 to 5°C) due to the influence of the Late Oligocene to Early Miocene tectonic compression at the junction of the southern Alps and Apennines. [ABSTRACT FROM AUTHOR]

During the Cretaceous, the Neuquén Basin transitioned from an extensional back-arc to a retroarc foreland basin. We present a multi-proxy provenance study of Aptian to Santonian (125-84 Ma) continental sedimentary rocks preserved in the Neuquén Basin used to resolve changes of sediment drainage pattern in response to the change in tectonic regime. Sandstone petrology and U-Pb detrital zircon geochronology constrain the source units delivering detritus to the basin; apatite U-Pb and fission track dating further resolve provenance and determine the age and patterns of exhumation of the source rocks. Sandstone provenance records a sharp change from a mixed orogenic source during Aptian time ( ca. 125 Ma), to a magmatic arc provenance in the Cenomanian ( ca. 100 Ma). We interpret this provenance change as the result of the drainage pattern reorganisation from divergent to convergent caused by tectonic basin inversion. During this inversion and early stages of contraction, a transient phase of uplift and basin erosion, possibly due to continental buckling, caused the pre-Cenomanian unconformity dividing the Lower from Upper Cretaceous strata in the Neuquén Basin. This phase was followed by the development of a retroarc foreland basin characterised by a volcanic arc sediment provenance progressively shifting to a mixed continental basement provenance during Turonian-Santonian (90-84). According to multi-proxy provenance data and lag times derived from apatite fission track analysis, this trend is the result of a rapidly exhuming source within the Cordillera to the west, in response to active compressional tectonics along the western margin of South America, coupled with the increasing contribution of material from the stable craton to the east; this contribution is thought to be the result of the weak uplift and exhumation of the foreland due to eastward migration of the forebulge. [ABSTRACT FROM AUTHOR]