Journey to the Mississippian-Pennsylvanian Boundary GSSP: a long and winding road

The mid-Carboniferous GSSP (Global Stratigraphic Section and Point) is placed at the base of sample 61B, 68 cm above the base of Unit G of the Bird Spring Formation, 19.6 m above the top of the Indian Springs Formation (82.90 m above the base of the Battleship Wash Formation) exposed in Arrow Canyon, southern Nevada, USA. Unit G is a 1.61 m succession of grainstones, packstones, and wackestones that was likely deposited continuously during the maximum flooding interval of a Late Mississippian Early Pennsylvanian T-R Cycle and preserves the FAD (First Appearance Datum) of the cosmopolitan conodont element Declinognathodus noduliferus (Ellison and Graves 1941) s. l., selected to define the Mississippian-Pennsylvanian boundary. For nearly twenty years, H. Richard (Rich) Lane guided this GSSP search beginning with the selection of the boundary horizon, through the evaluation of the candidate stratotypes, and concluding with the selection of the Arrow Canyon GSSP. Its ratification in 1996 as the 36th GSSP by the ICS (International Commission on Stratigraphy), established a contribution to the global understanding of Carboniferous stratigraphy for which Rich Lane will always be associated and remembered.