CHARACTERIZING THE CONTINENTAL-SCALE STRATIGRAPHIC ARCHITECTURE OF EUROPE USING SLOSS-TYPE SEQUENCES

Sequences are defined as discrete packages of sedimentary rock bounded by interregional erosional surfaces, making them ideal stratal units for regional stratigraphic study. We present a new continental-scale study of the six Sloss-type sequences across Europe, with emphasis on stratigraphic architecture.

Details of the sediments across Europe, including offshore shelf regions, were compiled into 481 stratigraphic columns using available publications, seismic data, and well records. RockWorks 17 software was used to track sequence boundaries, lithologic data, and locations. A three-dimensional lithology model, isopach maps, stratigraphic profiles and basal sequence lithology maps were created for each of the six sequences.

Results show that siliciclastics dominated deposition in the earliest two sequences (Sauk and Tippecanoe) and again in the last sequence, the Tejas. The earliest two sequences also had the least extent, with surface coverage of just over 5 million km² for both the Sauk and the Tippecanoe. Deposition of the Sauk and Tippecanoe was primarily limited to selected locations in westernmost Russia, north-central Europe and the Iberian Peninsula. The volume of siliciclastics in the earliest three sequences fluctuated between 2 and 4 million km³. In contrast, the volume of siliciclastics increased markedly in the Absaroka, ballooning to 15.5 million km³. The subsequent Zuni sequence shows a decrease in siliciclastic volume (8.9 million km³) before another large increase is observed in the Tejas sequence (14.1 million km³). In fact, siliciclastic deposition within Tejas was the highest in terms of percentage by volume at 74.9%.

Carbonate deposition reflected an inverse relationship to the siliciclastic patterns. Only the Kaskaskia sequence shows a dominance of carbonate deposition by volume at 52.9%. The relative amount of carbonate deposition then decreased in the later Absaroka sequence to 29.1%, whereas the actual volume of carbonate deposited showed an increase from 5.5 million km³ in the Kaskaskia to 7.7 million km³ in the Absaroka. The Kaskaskia, Absaroka and Zuni sequences all show relatively similar volumes of carbonate deposition, varying from 5.5 to 7.7 million km³. In contrast, the Sauk, Tippecanoe and Tejas all have carbonate depositional volumes at or less than 2.1 million km³.