geochronology, isotopes

Introduction to Geochronology

Have you ever wondered, “How do geologists know how old a rock is?”  Geochronology is the science of determining how old rocks, sediments and fossils are. Whether they formed 4 billion years ago or within the historic record, geologists can employ geochronologic methods to determine either the relative or absolute ages of these materials. Radiometric dating–which measures… Continue reading Introduction to Geochronology



Typically when you look at a geologic time scale, the Precambrian is all scrunched up, so even though it accounts for about 80% of Earth’s history, you forget how significant it is in the whole scheme of things. Putting the time scale into perspective like this just makes me marvel even more at human existence…… Continue reading ~4.55 BILLION YEARS – TO SCALE!


Some perspective on (geologic) time [w/ the Acasta gneiss!]

Due in large part to the lasting legacy of Christopher Columbus’s expeditions, North and South America will forever bear the mark of the “New World.” Whereas Europe has cathedrals centuries older than the United States itself, North America appears to not be able to offer much in terms of relics of antiquity. The earliest humans… Continue reading Some perspective on (geologic) time [w/ the Acasta gneiss!]