Comparing the Potential Bowland Shale Play (Pennine Basin, United Kingdom) to the Established Barnett Shale Play (Fort Worth Basin, U.S.A.): A Geochemical and Palynological Analysis of Mississippian (Carboniferous) Mudstones

Abstract

The Pennine Basin, now underlying much of northern England, comprised interlinked sub-basins formed under an extensional regime north of the Hercynic orogenic zone. During the Mississippian, the depositional history of the Pennine Basin, located in an equatorial position surrounded by emerging landmasses, was greatly influenced by glacio-eustatic sea level changes: organic rich mudstones, deposited in the deeper part of the basins during highstands, are interspersed with turbiditic levels.

In contrast, the Fort Worth Basin, a foreland basin formed in response to the collision between North and South America, was located more distally and its Mississippian deposits lack the characteristic turbidites of the Pennine Basin.

In the current study, we analysed samples from the Oliver A1 core (Tarrant County, Fort Worth Basin, Texas, USA) and the Grange Hill Core (Pennine Basin, Lancashire, UK). To keep correlation errors to a minimum, we use the same techniques in the same laboratory settings to analyse mudstones from both cores: Rock-Eval 6 pyrolysis, transmitted light and epifluorescence microscopy.

Rock-Eval and palynological analysis show a clear difference in maturity: the Oliver A1 core having much higher T_max values, much lower Hydrogen Indices (HI) whilst having comparable Total Organic Content (TOC). Palynomorphs from Oliver A1 samples exhibit a much more subdued fluorescence and amorphous organic matter is less dominant than in Bowland Shale material. In addition, we compare the emerging literature on the Pennine Basin to published materials on the Fort Worth Basin. In light of our findings, we re-evaluate the generative potential of the Namurian (Mississippian) mudstones of the Pennine Basin and how these compare to coeval mudstones from a proven shale gas play.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018