Boundary D Rift
valley
Midocean
ridge
Oceanic
crust
Lithosphere
Divergent
boundary
Asthenosphere
Name of boundary
Description of the motion
(sliding past, colliding, or
separating?)
What forms here? (look
at the land)
Rift valley
Boundary D
Divergent boundary
I
d speaker notes

Why is the huronian supergroup rock formation particularly interesting to scientists? because it looks like a cross-section of a giant, stone encyclopedia because it formed during the period when oxygen began to accumulate in the atmosphere because it contains unusually large amounts of oxygen and sulfur because it dramatically altered the planet's development when it first formed