Following voting by the Kimmeridgian Working Group,the International Subcommission on Jurassic Stratigraphy and the International Commission on Stratigraphy,the Global Stratotype Section and Point(GSSP)for the base of...Following voting by the Kimmeridgian Working Group,the International Subcommission on Jurassic Stratigraphy and the International Commission on Stratigraphy,the Global Stratotype Section and Point(GSSP)for the base of the Kimmeridgian Stage(Jurassic System)was ratified by the executive of the International Union of Geological Sciences.The boundary is placed in the upper part of Bed 35 of the Staffin Shale Formation,1.25±0.01 m below the base of Bed 36 in block F6 in the foreshore at Flodigarry,Staffin Bay,Isle of Skye,Scotland.The coordinates for the middle part of the two adjacent sections(sections F6N and F6S)are 57°39'39.5″N,6°14'43.9″W and 57°39'40.5″N,6°14'45″W;UK National Grid Scheme NG 46877139 and NG 46877142±5 m.This stratigraphic point coincides with the appearance over a short stratigraphic interval of several new ammonite taxa that delineate the base of the Subboreal ammonite Baylei Zone,the base of the Densicostata Subzone marked by the base of the flodigarriensis horizon,and,independently,the base of the Boreal ammonite Bauhini Zone.The main advantages of this locality are:the presence of a dual ammonite zonation marked by two extensively studied,well-preserved and very abundant groups of ammonites,and their preservation within a continuous section of~120 m of open marine,fossiliferous,thermally immature mudrocks with no evidence of condensation or stratigraphic gaps.Dinoflagellate cysts,magnetostratigraphy and stable isotope data from the same section provide secondary markers.The stratigraphic point is located 0.17–0.65 m below the boundary interval between the dinoflagellate cyst zones DSJ 26 and DSJ 27(equivalent to the boundary between subzones c and d of the Scriniodinium crystallinum(=Scr)Zone).展开更多
文摘Following voting by the Kimmeridgian Working Group,the International Subcommission on Jurassic Stratigraphy and the International Commission on Stratigraphy,the Global Stratotype Section and Point(GSSP)for the base of the Kimmeridgian Stage(Jurassic System)was ratified by the executive of the International Union of Geological Sciences.The boundary is placed in the upper part of Bed 35 of the Staffin Shale Formation,1.25±0.01 m below the base of Bed 36 in block F6 in the foreshore at Flodigarry,Staffin Bay,Isle of Skye,Scotland.The coordinates for the middle part of the two adjacent sections(sections F6N and F6S)are 57°39'39.5″N,6°14'43.9″W and 57°39'40.5″N,6°14'45″W;UK National Grid Scheme NG 46877139 and NG 46877142±5 m.This stratigraphic point coincides with the appearance over a short stratigraphic interval of several new ammonite taxa that delineate the base of the Subboreal ammonite Baylei Zone,the base of the Densicostata Subzone marked by the base of the flodigarriensis horizon,and,independently,the base of the Boreal ammonite Bauhini Zone.The main advantages of this locality are:the presence of a dual ammonite zonation marked by two extensively studied,well-preserved and very abundant groups of ammonites,and their preservation within a continuous section of~120 m of open marine,fossiliferous,thermally immature mudrocks with no evidence of condensation or stratigraphic gaps.Dinoflagellate cysts,magnetostratigraphy and stable isotope data from the same section provide secondary markers.The stratigraphic point is located 0.17–0.65 m below the boundary interval between the dinoflagellate cyst zones DSJ 26 and DSJ 27(equivalent to the boundary between subzones c and d of the Scriniodinium crystallinum(=Scr)Zone).
