Proposed and Ratified GSSP’s in Britain
In order to have a common and precise language of geologic time to understand Earth’s history, it is necessary to have a series of fixed points in geological history which together define the stage sub-divisions of the geological timescale. The International Commission on Stratigraphy (ICS) and its predecessors primary aim has been to unite the individual ‘regional scales’ by agreement on a standardized nomenclature and hierarchy for these stages, defined by precise Global Boundary Stratotype Sections and Points (GSSP). These on-going decisions are primarily controlled by the activities of the task forces of the various ICS sub-commissions. Some of these GSSP’s are defined or proposed in Britain, primarily because Britain contains some globally significant geological intervals, particularly in the Mesozoic and mid Palaeozoic. A list of these sites and sections in Britain are shown below, the full global list of ratified GSSP's is updated by the ICS.
Campanian Stage (83.5 ± 0.7 Ma): Candidates are in southern England (2, 3)and in Texas, at LAD of Crinoid Marsupites testudinarius.
Kimmeridgian Stage (155.6 ± 4 Ma): Candidate is Flodigarry (Isle of Skye, NW Scotland) 57.6000°N 6.2000°W Ammonite near base of the Pictonia baylei ammonite zone.
Oxfordian Stage (161.2 ± 4 Ma): Candidates are Redcliff Point (Dorset, SW England) and Savouron (Provence, SE France) at Ammonite Cardioceras redcliffense Horizon at the base of the Cardioceras scarburgense Subzone (Quenstedtoceras mariae Zone)
Pliensbachian Stage (189.6 ± 1.5 Ma). Ratified at Wine Haven, Robin Hood's Bay, Yorkshire Coast, England 54.4069°N 0.4975°W base of Bed 73b at Ammonite association of Bifericeras donovani and Apoderoceras sp. More information and stratigraphic details of section.
Sinemurian Stage (196.5 ± 1 Ma). Ratified at East Quantoxhead, SW England 51.1909°N 3.2364°W 0.90 m above the base of Bed 145 at the Ammonite FAD Vermiceras quantoxense, Vermiceras palmeri. More information and stratigraphic details of section.
Hettangian and base Jurassic (199.6 ± 0.6 Ma). The ratified GSSP for this stage base is in Austria. Although two proposed candidates, one at St Audrie's Bay (Somerset) and a 2nd at Waterloo Bay (Northern Island) were considered as strong candidates.
Ludfordian Stage (421.3 ± 2.6 Ma). Ratified near Ludlow, UK 52.3592°N 2.7772°W coincident with the base of the Leintwardine Formation, near the base of the Saetograptus leintwardinensis Graptolite zone. More information and stratigraphic details of section.
Gorstian Stage (422.9 ± 2.5 Ma). Ratified near Ludlow, UK 52.3592°N 2.7772°W coincident with the base of the Lower Elton Formation, at the FAD of Graptolite Saetograptus (Colonograptus) varians. More information and stratigraphic details of section.
Homerian Stage (426.2 ± 2.4 Ma). Ratified at Sheinton Brook, Homer, UK 52.6156°N 2.5647°W within upper part of the Apedale Member of the Coalbrookdale Formation at the FAD of Graptolite Cyrtograptus lundgreni. More information about section.
Sheinwoodian Stage (428.2 ± 2.3 Ma). Ratified at Hughley Brook, UK 52.5811°N 2.6389°W base of the Buildwas Formation,. between the base of acritarch biozone 5 and LAD of conodont Pterospathodus amorphognathoides. More information and stratigraphic details of section.
Telychian Stage ( 436 ± 1.9 Ma). Ratified at Cefn-cerig Road Section, Wales, UK 51.9700°N 3.7900°W within the Wormwood Formation, just above Brachiopod LAD Eocoelia intermedia and below FAD of Eocoelia curtisi. More information and stratigraphic details of section.
Aeronian Stage (439 ± 1.8 Ma). Ratified at Trefawr Track Section, Wales, UK 52.0300°N 3.7000°W within Trefawar Formation, at FAD of Graptolite Monograptus austerus sequens. More information and stratigraphic details of section.
Base of the Silurian and the Rhuddanian Stage (443.7 ± 1.5 Ma). Ratified at Dob's Linn(1,2), Scotland 55.4400°N 3.2700°W 1.6 m above the base of the Birkhill Shale Formation, at FAD of Graptolite Akidograptus ascensus. More information and stratigraphic details of section.
Campanian Stage (83.5 ± 0.7 Ma): Candidates are in southern England (2, 3)and in Texas, at LAD of Crinoid Marsupites testudinarius.
Kimmeridgian Stage (155.6 ± 4 Ma): Candidate is Flodigarry (Isle of Skye, NW Scotland) 57.6000°N 6.2000°W Ammonite near base of the Pictonia baylei ammonite zone.
Oxfordian Stage (161.2 ± 4 Ma): Candidates are Redcliff Point (Dorset, SW England) and Savouron (Provence, SE France) at Ammonite Cardioceras redcliffense Horizon at the base of the Cardioceras scarburgense Subzone (Quenstedtoceras mariae Zone)
Pliensbachian Stage (189.6 ± 1.5 Ma). Ratified at Wine Haven, Robin Hood's Bay, Yorkshire Coast, England 54.4069°N 0.4975°W base of Bed 73b at Ammonite association of Bifericeras donovani and Apoderoceras sp. More information and stratigraphic details of section.
Sinemurian Stage (196.5 ± 1 Ma). Ratified at East Quantoxhead, SW England 51.1909°N 3.2364°W 0.90 m above the base of Bed 145 at the Ammonite FAD Vermiceras quantoxense, Vermiceras palmeri. More information and stratigraphic details of section.
Hettangian and base Jurassic (199.6 ± 0.6 Ma). The ratified GSSP for this stage base is in Austria. Although two proposed candidates, one at St Audrie's Bay (Somerset) and a 2nd at Waterloo Bay (Northern Island) were considered as strong candidates.
Ludfordian Stage (421.3 ± 2.6 Ma). Ratified near Ludlow, UK 52.3592°N 2.7772°W coincident with the base of the Leintwardine Formation, near the base of the Saetograptus leintwardinensis Graptolite zone. More information and stratigraphic details of section.
Gorstian Stage (422.9 ± 2.5 Ma). Ratified near Ludlow, UK 52.3592°N 2.7772°W coincident with the base of the Lower Elton Formation, at the FAD of Graptolite Saetograptus (Colonograptus) varians. More information and stratigraphic details of section.
Homerian Stage (426.2 ± 2.4 Ma). Ratified at Sheinton Brook, Homer, UK 52.6156°N 2.5647°W within upper part of the Apedale Member of the Coalbrookdale Formation at the FAD of Graptolite Cyrtograptus lundgreni. More information about section.
Sheinwoodian Stage (428.2 ± 2.3 Ma). Ratified at Hughley Brook, UK 52.5811°N 2.6389°W base of the Buildwas Formation,. between the base of acritarch biozone 5 and LAD of conodont Pterospathodus amorphognathoides. More information and stratigraphic details of section.
Telychian Stage ( 436 ± 1.9 Ma). Ratified at Cefn-cerig Road Section, Wales, UK 51.9700°N 3.7900°W within the Wormwood Formation, just above Brachiopod LAD Eocoelia intermedia and below FAD of Eocoelia curtisi. More information and stratigraphic details of section.
Aeronian Stage (439 ± 1.8 Ma). Ratified at Trefawr Track Section, Wales, UK 52.0300°N 3.7000°W within Trefawar Formation, at FAD of Graptolite Monograptus austerus sequens. More information and stratigraphic details of section.
Base of the Silurian and the Rhuddanian Stage (443.7 ± 1.5 Ma). Ratified at Dob's Linn(1,2), Scotland 55.4400°N 3.2700°W 1.6 m above the base of the Birkhill Shale Formation, at FAD of Graptolite Akidograptus ascensus. More information and stratigraphic details of section.