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The intricate basins (Kura and Rioni) located between the Greater and the Lesser Caucasus are the site of several hydrocarbon fields. In eastern Georgia, the Samgori field in the western end of the vast Kura basin extends into Azerbaijan. It is the largest hydrocarbon discovery in Georgia, with a cumulative production of more than 250MbO. In western Georgia in the western and southern Rioni, only small size fields have been discovered (East Chaladidi, Supsa or Shromisubani, a few MbOE produced).The ingredients of the petroleum system belong to the Tertiary : source rocks from the Maikop formation, siliciclastics and volcanoclastics reservoirs, shaly intervals as cap rocks, and Neogene structures linked to the structuration of the Greater and Lesser Caucasus fold belts.The Mesozoic series in the Kura basin constitute a speculative hydrocarbon target to be explored in the future although at greater depth below the Tertiary folds. In the Kartli sub-basin at the western end of the Kura basin, there is only scattered and often over-matured Mesozoic series to look for source, reservoir and cap rocks analogs.In the Rioni basin, less mature Mesozoic series crop out, offering a possible evaluation of all the geologic elements and processes essential to an hydrocarbon accumulation. A preliminary investigation of the Mesozoic series revealed several organic rich horizons, reservoirs and cap rocks in the pre Cretaceous series. This leads to propose a schematic pre-Cretaceous paleogeography constituting the base for defining possible petroleum systems. Preliminary organic geochemical analyses of organic-rich horizons lead to identify several layers having fair to moderate hydrocarbon potential for oil and gas. Based on this preliminary result, information derived from bibliography and published seismic lines, and 1D modeling with Petromod software lead to propose new potential plays in the Rioni basin.This speculative study requires new biostratigraphic studies to confirm the ages of the various identified organic rich horizons, some of them being possibly new to refine the modelings. More detailed fieldwork should focus on reservoir quality and distribution. Eventually, analysis of reprocessed seismic data will permit to confirm new petroleum thematics.

International audience; The SW-Gissar range (westernmost part of the Tien Shan) consists of a succession of anticlines andsynclines forming a relief between the Amu Darya and Afghan-Tajik basins. Recent fieldwork has beenperformed to study the development and the architecture of a vast Middle-Upper Jurassic carbonate platform. The studied carbonate series crops out along cliffs overlying Lower to Middle Jurassic continental then marine deposits. Carbonate thickness reaches 500 m in the central and southern Gissar and thins up northwards, near the paleo-border of the Amu Darya Basin. The goal of this study was to build a highresolution stratigraphic framework for these deposits, based on chemo-and lithostratigraphic correlations between seven sections. It was associated with a detailed microfacies analysis in order to establish the spatial and temporal evolution of the palaeoenvironments in this poorly known area. Two major sequences were recognized, (1) Callovian in age, and (2) possibly Oxfordian to Lower Tithonian. The reconstruction of the deposition profile indicates that the Gissar was a gently dipping ramp during the Callovian major sequence. Dark mudstones with entire bivalve and brachiopod shells and oncoids-rich float-to rudstones predominated below and around the storm wavebase. Oobioclastic grainstones were deposited in the permanently agitated shallow water zone, while patch and pinnacle reefs built up distally at the inner-mid ramp transition and in the mid ramp. Small shallow water siliciclastic deltas developed close to the emerged lands located in the north. The Callovian sequence is subdivided into seven fourth-order transgressive-regressive sequences. The transition between the two major sequences is marked by a significant change in the carbonate sedimentary system associated with a positive shift in the bulk carbon isotope values. It could record a major climatic change coeval with the Middle-Late Jurassic Transition. Further, it is hypothesized that a sedimentary hiatus exists, possibly caused by the exposure of the platform. The Upper Jurassic major sequence is mostly composed of peritidal deposits, showing rapid vertical and lateral transitions, depicting a more complex architecture. The series consists in numerous meterthick alternations of pellets/algal pack-to grainstone, ‘microbial oncoid’ floatstone, ooid grainstones and mudstones. These deposits could have accumulated in a vast, mostly aggrading lagoon protected by a barrier reef. Basinwards, close to the Uzbek-Turkmen border, Middle Oxfordian organic-rich algal/microbial carbonates are intercalated within the platform carbonates and could have formed in small stratified and partly isolated intra-shelf depressions. Lastly, a general aridification of the basin could be responsible for the observed increase in gypsum characterizing the upper part of the carbonate platform (Late Oxfordian? to Tithonian?). The numerous oscillations in carbon isotopes evidenced in these evaporite-rich carbonates may be the consequence of high frequency exposure of the platform preceding the deposits of massive evaporite during the Tithonian. This study allows a better understanding of the paleoenvironmental evolution of the northern Tethys during the Middle and Upper Jurassic. Our results will be compared with other Peri-Tethyan Jurassic platforms in order to understand the carbonate platform response to large-scale climatic and tectonic changes occurring at this period.

International audience; New investigations are currently underway on the Middle-Upper Jurassic carbonates of the Gissar Mountains in the Amu-Darya Basin. Located in the southwest of the Gissar Mountains (SE Uzbekistan), the Tubiegatan section corresponds to 30-meter-thick limestone, overlain by 10-meter-thick dark limestone and marl interval. These dark, “black shale-type deposits” were also recognized in cores from the subsurface of the Amu-Darya Basin. The organic-rich deposits interval is precisely dated to the Luciaeformis and Schilli Subzones (Transversarium Zone, Middle Oxfordian) by ammonites. A transdisciplinary approach including sedimentology, organic matter characterization (Rock-Eval pyrolysis, palynofacies), bulk and clay mineralogy (XRD), carbon and oxygen isotopes of carbonate and organic fractions and whole rock trace-element geochemistry were used to elucidate the origin of these organic-rich deposits. Carbon-isotope curves were also established to help to correlate this interval with the partly contemporaneous carbonate platform. Both Tmax from Rock Eval analysis and clay mineral assemblages indicate a pronounced burial diagenesis (oil window).Despite this burial, paleoenvironmental and paleoclimatic can still be processed. Rock-Eval pyrolysis analyses performed on 65 samples show that TOC values range from 0 (peloidal grainstone) to 6 % on average for the thinly laminated black limestone. Interestingly, in this dark organic-rich deposits interval, higher TOC were measured in limestone (2% on average), while lower TOC values (0.5% on average) characterized marl and claystone, which is relatively unusual. Rock-Eval parameters (IH, IO) coupled to palynofacies observations (predominant amorphous organic matter) point to a probable marine, algal/microbial origin for the organic matter (Type II), with rare continental inputs mostly located in the upper part. Trace elements, as well as palynofacies and sedimentological observations demonstrate local O2-depleted conditions promoting the preservation of organic matter. Such paleoenvironmental conditions may have supported bacterial mineralization processes related to anaerobic oxidation of methane, which would explain the very low δ13C values (-5‰ to -12‰) measured in laminated facies. From the base of the organic-rich interval, a progressive decrease then disappearance of kaolinite, balanced by illite and illite/smectite mixed-layers (type R1), is observed. This coincides with the development of terrestrial phytoclasts inputs, suggesting a probable aridification in the Amu Darya Basin during the Middle/Late Oxfordian. Overall, the organic-rich deposits of Tubiegatan could record the onset of the disconnection of the Amu-Darya Basin from the open sea in the south, induced by compression and uplifts in the Afghan and Central Iranian blocks.This disconnection, combined with a Tethys-wide aridification could have led to the progressive increase of evaporation and subsequent deposits on the carbonate platform, followed by the massive uppermost Jurassic evaporites (salt, anhydrite) of the Gaurdak Fm.

International audience; The post-rift (20-0 Ma) vertical movements of the Provence Basin (West Mediterranean) are quantified on itsboth conjugate (the Gulf of Lion and the West Sardinia) margins. This work is based on the stratigraphic studyof sedimentary markers using a large 3D grid of seismic data, correlations with existing drillings and refractiondata. The post-rift subsidence is measured by the direct use of sedimentary geometries analysed in 3D [Gorini etal., 2015; Rabineau et al., 2014] and validated by numerical stratigraphic modelling. Three domains were found:on the platform (1) and slope (2), the subsidence takes the form of a seaward tilting with different amplitudes,whereas the deep basin (3) subsides purely vertically [Leroux et al., 2015a]. These domains correspond to thedeeper crustal domains respectively highlighted by wide angle seismic data. The continental crust (1) and thethinned continental crust (2) are tilted, whereas the intermediate crust, identified as lower continental exhumedcrust [Moulin et al., 2015, Afhilado et al., 2015] (3) sagged. The post-break-up subsidence re-uses the initial hingelines of the rifting phase. This striking correlation between surface geologic processes and deep earth dynamicprocesses emphasizes that the sedimentary record and sedimentary markers is a window into deep geodynamicprocesses and dynamic topography.Pliocene-Pleistocene seismic markers enabled high resolution quantification of sediment budgets over the past6 Myr [Leroux et al., in press]. Sediment budget history is here completed on the Miocene interval. Thus, thecontrolling factors (climate, tectonics and eustasy) are discussed.Afilhado, A., Moulin, M., Aslanian, D., Schnürle, P., Klingelhoefer, F., Nouzé, H., Rabineau, M., Leroux,E. & Beslier, M.-O. (2015). Deep crustal structure across a young 1 passive margin from wide-angle and reflectionseismic data (The SARDINIA Experiment) - II. Sardinia’s margin. Bull. Soc. géol. France, 186, ILP Spec. issue,4-5, 331-351.Gorini, C., Montadert, L., Rabineau, M., (2015) New imaging of the salinity crisis: Dual Messinian lowstandmegasequences recorded in the deep basin of both the eastern and western Mediterranean, Marine and PetroleumGeology (2015), doi: 10.1016/j.marpetgeo.2015.01.009.Leroux, E., Aslanian, D., Rabineau, M., Moulin, M., Granjeon, D., Gorini C. & Droz, L. (2015a). Sedimentarymarkers in the Provençal basin (Western Mediterranean): a window into deep geodynamic processes. Terra Nova,27(2), 122-129.Leroux, E., Rabineau, M., Aslanian, D., Gorini, C., Molliex, S., Bache, F., Robin, C., Droz, L., Moulin, M.,Poort, J., Rubino, J.-L. & Suc, J.P. (2016, in press). High resolution evolution of terrigenous sediment yieldsin the Provence Basin during the last 6 Ma: relation with climate and tectonic. Basin Research, xx, xx-xx (ID:4759575-1545130).Moulin, M., Klingelhoefer, F., Afiladho, A., Aslanian, D., Schnürle, P., Nouze, H., Beslier, M.-O. & Feld, A.(2015). Deep crustal structure across an young passive margin from wide-angle and reflection seismic data (TheSARDINIA Experiment) - I. Gulf of Lion’s margin, Bull. Soc. géol. France., 186, ILP Spec. issue, 4-5,309-330.Rabineau, M., Leroux, E., Aslanian, D., Bache, F., Gorini, C., Moulin, M., Molliex, S., Droz, L., Reis, T. D.,Rubino, J.-L., Guillocheau, F. & Olivet, J.-L. (2014). Quantifying subsidence and isostatic readjustment usingsedimentary markers (example in the Gulf of Lion). Earth and Planetary Science Letters, 388, 1-14

The one of the most important Eras of the Earth history, i.e. Neoproterozoic (1000-542 Ma),was an enigmatic period characterized by the development of the first stable long-lived ~1.1-0.9 Ga Rodinia and 550-500 Ma Gondwana supercontinents, global-scale orogenic belts,extreme climatic changes (cf. Snowball Earth Hypothesis), the development of microbialorganisms facilitating the oxidizing atmosphere and explosion of eukaryotic forms toward thefirst animals in the terminal Proterozoic. This thesis presents a multidisciplinary study of twoNeoproterozoic basins, i.e. Bas-Congo and Sankuru-Mbuji-Mayi-Lomami-Lovoy, in and around the Congo Craton including sedimentology, geochemistry, diagenesis, chemostratigraphy and radiometric dating of carbonate deposits themselves.The Mbuji-Mayi Supergroup sequence deposited in a SE-NW trending 1500 m-thick siliciclastic-carbonate intracratonic failed-rift basin, extends from the northern Katanga Province towards the centre of the Congo River Basin. The 1000 m-thick carbonate succession is related to the evolution of a marine ramp submitted to evaporation, with ‘deep’ shaly basinal and low-energy carbonate outer-ramp environments, marine biohermal midramp (MF6) and ‘very shallow’ restricted tide-dominated lagoonal inner-ramp (MF7-MF9) settings overlain by lacustrine (MF10) and sabkha (MF11) environments, periodicallysubmitted to a river water source with a possible freshwater-influence. The sequence stratigraphy shows that the sedimentation is cyclic in the inner ramp with plurimetric ‘thin’ peritidal cycles (± 4 m on average) recording a relative sea level of a maximum of 4 m, with fluctuations in the range of 1-4 m. The outer/mid ramp subtidal facies are also cyclic with ‘thick’ subtidal cycles characterized by an average thickness of ± 17 m, with a probable sealevelfluctuations around 10 to 20 m. The geochemistry approach, including isotopic and major/trace and REE+Y data, allows to infer the nature of the dolomitization processes operating in each carbonate subgroup, i.e dolomitization may be attributed to evaporative reflux of groundwater or to mixing zones of freshwater lenses. The latest alteration processes occured during the uplift of the SMLL Basin. New ages, including LA-ICP-MS U-Pb laser ablation data on detrital zircon grains retrieved in the lower arenaceous-pelitic sequence (BI group), combined with carbon and strontium isotopic analyses, yielded a new depositional time frame of the Mbuji-Mayi Supergroup between 1176 and 800 Ma reinforcing the formerly suggested correlation with the Roan Group in the Katanga Province.In the Democratic Republic of Congo, the Sturtian-Marinoan interglacial period was previously related to pre-glacial carbonate-dominated shallow marine sedimentation of the Haut-Shiloango Subgroup with stromatolitic reefs at the transition between greenhouse (warm) and icehouse (cold) climate periods, commonly marked by worldwide glacigenic diamictites and cap carbonates. This thesis highlights that these deposists record as a deepening-upward evolution from storm-influenced facies in mid- and outer-ramps to deepwater environments, with emplacement of mass flow deposits in toe-of-slope settings controlled by synsedimentary faults. In absence of diagnostic glacial features, the marinoan Upper Diamictite Formation is interpreted as a continuous sediment gravity flow deposition along carbonate platform-margin slopes, which occurred along tectonically active continental margins locally influenced by altitude glaciers, developed after a rift–drift transition. The maximum depth of the deepening-upward facies is observed in the C2a member. Theshallowing-upward facies exibit a return of distally calcareous tempestites and semi-restricted to restricted peritidal carbonates associated with shallow lagoonal subtidal and intertidal zones submitted to detrital fluxes in the upper C2b to C3b members.The geochemistry highlights (i) the existence of a δ13C-depth gradient of shallow-water and deep-water carbonates; (ii) the carbonate systems were deposited in oxic to suboxic conditions; and (iii) all samples have uniform flat non-marine shale-normalized REE+Y distributions reflectingcontinental detrital inputs in nearshore environments, or that the nearshore sediments werereworked from ’shallow’ inner to mid-ramp settings in deep-water slope and outer-rampenvironments, during the rift-drift transition in the basin. The pre-, syn- and post-glacialcarbonate systems could record a distally short-lived regional synrift freshwater-influencedsubmarine fan derived from nearshore sediments, including gravity flow structures, which areattributed to regional tectonic processes due to a sudden deepening of the basin caused bydifferential tilting and uplifting of blocks, related to the 750-670 Ma oceanic spreading of thecentral-southern Macaúbas Basin.Combining sedimentology, isotopes and trace elemental geochemistry, the thesis highlightsthat the δ13C variations in the Neoproterozoic carbonates are complex to interpret, and can berelated to: (i) the existence of a δ13C-depth gradient; (ii) the exchange between isotopicallylight carbon in meteoric waters and carbonate during lithification and early diagenesis; and(iii) isotopic perturbations due to regional metamorphism. Considering the possible englaciation of the Earth (Snowball Earth hypothesis), the Mbuji-Mayi Supergroup and WestCongolian Group seem reflected the intimate relationship between glaciations and tectonicactivity during the break-up of the Rodinia supercontinent, followed by the rift–drifttransition, and finally the pre-orogenic period on the passive continental margin., Doctorat en Sciences, info:eu-repo/semantics/nonPublished