What produced the iron in the Earth's core?

Question

what produced the iron in the earth's core? and also the heaevier elements like gold and silver in the earth's crust?

Answer 1

According to cosmology it is believed that iron (along with other "heavy" elements) formed from supernova explosions of red giant stars. The mechanisms that place gold, silver and other (very) heavy elements within the crust are not clearly understood, and I have not seen a good explanation for it. Economic Geology shows that due to subduction of oceanic plates these elements are concentrated at various distances away from the subduction, and this is a product of mantle/crust differentiation. A similar process may have occurred in the early history of the Earth when core/mantle differentiation occurred.