Pre- to early-rift thermal conditions of the Upper Rhine Graben using geological and organic geochemical controls

The Toarcian Posidonia Shale and Hettangian/Sinemurian Formation are the two main Mesozoic source rocks of Upper Rhine Graben (URG). Their thermal maturities measured used to reconstruct history URG. However, maturity these was impacted by: 1) pre-rift burial which includes a 120 My hiatus from Jurassic Paleocene; 2) syn- post-rift histories; 3) current high geothermal gradients associated hydrothermal convective cells. In this study, Saverne Fracture Field is considered analogue URG therefore bears witness history. It isolated graben upon its opening, i.e. in Priabonian, contains same rocks, which, contrast URG, currently outcropping. As were not buried as their should be consequence Jurassic/Cretaceous only. Organic geochemistry results indicate that they pre-oil window maturity. Calibration model for period allows us estimate during additional did exceed about 300 m. sediments cannot attributed specifically or Cretaceous. simulation if Cretaceous deposited, had preserved until Paleocene, maximum cumulative thickness must have been at most 100 addition, modelling indicates very first onset could again by 250 m Cenozoic sediments, with negligible effect signature. These geochemical geological constraints key input further modelling. Indeed, such on therma allow future assessment syn-rift recent cells impact