Gold is a lot heavier than iron, so maybe the following does not apply to that but: We can't interpret such cutoffs as being strict.
I would say, reaction speed depends on the gap between energy available and energy required but there's a lot of environments where the reaction can still happen at a fractional rate even if the mean energy level is below the minimum required.
Iron is at the peak but in environments where it could be formed, slightly heavier elements could also be formed at a slow rate.
I would say, reaction speed depends on the gap between energy available and energy required but there's a lot of environments where the reaction can still happen at a fractional rate even if the mean energy level is below the minimum required.
Iron is at the peak but in environments where it could be formed, slightly heavier elements could also be formed at a slow rate.