_________formed during the Precambrian under reducing conditions when the atmosphere was depleted in oxygen.
A) Sulphur zones
B) Goethite veins
C) Limonite rust fillings
D) Banded iron formation (Superior type)

Question

Quizplus · Accepted Answer

Banded iron formations (BIFs) are sedimentary rocks consisting of alternating layers of iron-rich minerals and silica (or chert). They primarily formed during the Precambrian era, a time when the Earth's atmosphere had very little oxygen. The reducing conditions of the early Earth's atmosphere facilitated the precipitation of iron from the oceans, leading to the formation of these extensive iron deposits.

_________Formed During the Precambrian Under Reducing Conditions When the Atmosphere