 In addition, Krogh's laboratory methods for the dissolution of minerals and the subsequent chemical separation of trace quantities of uranium and lead resulted in a significant reduction of environmental Pb contamination (blank) to ultra-low levels, and permitted increasingly small quantities of mineral grains and sub-grain domains to be analyzed.In the mid-1980s, he was instrumental in producing a synthetic 205Pb isotopic tracer (spike) that was distributed for use in U-Pb geochronology laboratories worldwide.The application of Krogh's novel and innovative techniques has revolutionized U-Pb geochronology and permitted the ages of rocks to be determined with unprecedented accuracy and precision.