GOLDEN SPIKE

A Global Boundary Stratotype Section and Point (GSSP) is a reference point on a stratigraphic section which defines the lower boundary of a geologic time scale stage. Once a GSSP boundary has been agreed upon, a “golden spike” (neither golden nor spiked) is laid into the geologic section to mark the precise boundary for future geologists. There are currently 75 ratified spikes; just one, in South Australia, is in the Southern Hemisphere.