Digital geochronological index

A digital geochronological index to act as a domain constraint for geochronology columns in corporate data tables. It decodes geochronology codes, models pseudo parent-child relationships between intervals (for example, find the epochs within a given period), allows range searches (for example, find the epochs between lower limiting and upper limiting epochs) and provides radiometric ages with ranges of uncertainty. Follows the recommendations of the BGS Stratigraphy Committee. Phanerozoic after Gradstein and Ogg (1996), with the Ordovician scheme of Fortey et al. (1995); Proterozoic after Cowie and Bassett (1989); Archaean after an unpublished decision of the Precambrian Subcommission of the IUGS. Covers the whole of geological time. Geochronological resolution usually to age level. Lower resolution in the Archaean, Proterozoic, Cambrian. Greater resolution in the Caradoc Epoch.

本数据集构成一个数字地质年代学索引，旨在作为企业数据表中地质年代学列的领域约束。该索引解码地质年代学代码，模拟区间之间的假父母-子关系（例如，在特定时期内寻找时代），支持范围搜索（例如，在上下限时代之间寻找时代）并提供带有不确定度范围的放射性年龄。遵循英国地质调查局地层委员会的建议。采用Gradstein和Ogg（1996年）的显生宙地层划分，以及Fortey等人（1995年）的奥陶纪地层方案；采用Cowie和Bassett（1989年）的太古宙地层划分；采用国际地质科学联合会前寒武纪委员会未发表决定的始太古代地层划分。涵盖整个地质时代。地质年代学分辨率通常至年龄级别。在始太古代、太古宙和寒武纪地层中分辨率较低。卡德洛克时代分辨率较高。