This doctoral thesis deals with a suite of drilling cores and outcrop samples of the Lower Toarcian Posidonia Shale (PS) collected from multiple locations covering a vast area including the Swabian Alb (SA) and Franconian Alb (FA) of Southwest-Germany, Wenzen well (WEN) of Hils syncline, northern Germany, Runswick Bay of UK, Loon op Zand well (LOZ-1) of the West Netherlands Basin (WNB) and the Esch-sur-Alzette, Luxembourg (LU). Based on a series of laboratory measurements, firstly, shale oil potential was assessed including thermal maturity. In order to quantify the petroleum generation potential of the rocks a large set of experimental analyses was conducted including elemental analysis, Rock-Eval pyrolysis, organic petrographic investigations and molecular hydrocarbon analyses. Secondly, three types of depositional environments of the Posidonia Shale from these six different sampling localities were deduced mainly based on organic geochemical characteristics.The Lower Toarcian Shale is more carbonate-rich (about 30 % on average) in SW-Germany, NW-Germany and Luxembourg, and is instead more silicate-rich in UK and NL with carbonate contents of about 15% on average. However, HI values are similar, approx. 500-700 mg HC/g TOC on average at all sampling localities, exhibiting typical type II kerogen with excellent hydrocarbon generation potential. Samples from outcrops of the Lower Toarcian Shale from Runswick Bay, UK, have reached the early stage of the oil window, with quite uniform Tmax values (425-438°C, avg. 433 °C) and a narrow range of PI (production index) values (0.10-0.19), substantiated by mature fluorescing characteristics of telalginite and lamalginite and vitrinite reflectance values of 0.6-0.7%. Wider ranges of Tmax values (421-443°C, avg. 427°C), vitrinite reflectance (0.4-0.8%) and production indices (0.06-0.29) suggest more variable thermal maturation ranging from immature to almost peak oil generation at the LOZ-1 well, NL, although only some intervals indicate advanced thermal maturity there. ...