How did large iron deposits, called banded iron formations, form?
A) hot water circulates along the margins of a caldera
B) groundwater mixes with seawater in the subsurface
C) magma releases metal-rich fluids that replace reactive rocks
D) an increase in oxygen in Earth's atmosphere caused seas to precipitate beds of iron-rich minerals

Question

How did large iron deposits, called banded iron formations, form? 
A) hot water circulates along the margins of a caldera 
B) groundwater mixes with seawater in the subsurface 
C) magma releases metal-rich fluids that replace reactive rocks 
D) an increase in oxygen in Earth's atmosphere caused seas to precipitate beds of iron-rich minerals

Quizplus · Accepted Answer

The Answer of How did large iron deposits, called banded iron formations, form? 
A) hot water circulates along the margins of a caldera 
B) groundwater mixes with seawater in the subsurface 
C) magma releases metal-rich fluids that replace reactive rocks 
D) an increase in oxygen in Earth's atmosphere caused seas to precipitate beds of iron-rich minerals

How Did Large Iron Deposits, Called Banded Iron Formations, Form