On The Geologic Time Scale

作者：Felix M. Gradstein, James G. Ogg, Frits J. Hilgen · 发表于：Newsletters on Stratigraphy · 年份：2012 · 被引用次数：748 · 研究领域：Geology and Paleoclimatology Research、Geochemistry and Geologic Mapping、Evolution and Paleontology Studies

This report summarizes the international divisions and ages in the Geologic Time Scale, published \nin 2012 (GTS2012). Since 2004, when GTS2004 was detailed, major developments have taken place \nthat directly bear and have considerable impact on the intricate science of geologic time scaling. Precam brian \nnow has a detailed proposal for chronostratigraphic subdivision instead of an outdated and abstract chronometric \none. Of 100 chronostratigraphic units in the Phanerozoic 63 now have formal definitions, but stable \nchronostratigraphy in part of upper Paleozoic, Triassic and Middle Jurassic/Lower Cretaceous is still wanting. \nDetailed age calibration now exist between radiometric methods and orbital tuning, making 40Ar-39Ar dates \n0.64% older and more accurate. In general, numeric uncertainty in the time scale, although complex and not \nentirely amenable to objective analysis, is improved and reduced. Bases of Paleozoic, Mesozoic and Cenozoic \nare bracketed by analytically precise ages, respectively 541 0.63, 252.16 0.5, and 65.95 0.05 Ma. \nHigh-resolution, direct age-dates now exist for base-Carboniferous, base-Permian, base-Jurassic, base-Cenomanian \nand base-Eocene. Relative to GTS2004, 26 of 100 time scale boundaries have changed age, of which \n14 have changed more than 4 Ma, and 4 (in Middle to Late Triassic) between 6 and 12 Ma. There is much \nhigher stratigraphic resolution in Late Carboniferous, Jurassic, Cretaceous and Paleogene, and improved integration...