NGU GEOCHRON: Database and analysis package for Norwegian isotope geochronology
Isotope geochronologic data analysis is an integral aspect of nearly every type of tectonic study. However, no regional compilation of Norwegian geo- chronologic data has been assembled since 1986 (Kullerud and co-workers for the Western Gneiss Region), despite the plethora of new, high-precision geochronologic data produced in the intervening 11 years. This report describes NGU GEOCHRON software, a new Windows-95/NT database and analysis package written to address these new developments in a rigorous and user- friendly format. The purpose of the program is to make available a database of all reliable, public isotopic age data from Norway, categorized according to particular geologic and geographic regions, rock types, isotopic methods and/or data authors, that can then be subjected to various forms of statistical analysis according to user-defined selection criteria. We describe the program setup and operation and the data sources for the software, in addition to providing some examples for application of isotope age data compilations and statistical analyses to address different sorts of tectonic questions. The precision of isotopic techniques and numerous new data in the literature demand a means for age-data access and analysis, especially within the context of our present understanding of the tectonic settings and tectonostratigraphy of Norwegian geology. This software package allows the user to re-evaluate old age data and to incorporate newer, high-precision ages and their geographic distributions for a variety research interests (provenance, rifting events, uplift/cooling events, crustal formation, faulting and extension, ore depo- sition, e.g.). Future expansion of the database will incorporate all isotopic age data from the Norwegian continental shelf, East Greenland, Svalbard and the U.K.