It is a pleasure to announce that the proposals for the subdivision of the Holocene Series/Epoch into three stages/ages and their corresponding subseries/subepochs by the International Subcommission on Quaternary Stratigraphy (ISQS) (a subcommission of the International Commission on Stratigraphy - ICS) have been ratified unanimously by the International Union of Geological Sciences (IUGS). The subdivisions are now formally defined as follows:
Boundary Stratotype (GSSP): NorthGRIP2 ice core, Greenland (coincident with the Holocene Series/Epoch GSSP, ratified 2008). Age: 11,700 yr b2k (before AD 2000).
Boundary Stratotype (GSSP): NorthGRIP1 ice core, Greenland. Global AuxiliaryStratotype: Gruta do Padre Cave speleothem, Brazil. Age: 8326 yr b2k.
Boundary stratotype (GSSP): Mawmluh Cave speleothem, Meghalaya, India. Global Auxiliary Stratotype, Mount Logan ice core, Canada. Age: 4250 yr b2k.
These divisions are now each defined by Global Stratotype Sections and Points (GSSPs) which means that the divisions are fixed in time in sedimentary sequences. The terms Greenlandian Stage/Age , Northgrippian Stage/Age, Meghalayan Stage/Age, Lower/Early Holocene Subseries/Subepoch, Middle/Mid-Holocene Subseries/Subepoch and Late/Upper Holocene Subseries/Subepoch therefore have formal definitions and boundaries (note formal stratigraphical terms must have capitalised first letters). If the terms are used informally, lower-case first letters should be used (except for Holocene) – editors please note!
These definitions represent the first formal geological subdivision of the Holocene Series/Epoch and are the result of over a decade of labour by members of the joint ISQS INTIMATE Members Working Group (Integration of Ice-core, Marine and Terrestrial Records) and the International Subcommission on Quaternary Stratigraphy, led by Professor Mike Walker. To these colleagues we owe a great debt of thanks. Formal publication of the justifications and definitions of each of the divisions will follow.
Secretary General ICS