African diamonds are recovered from which deposit types?

African diamonds are recovered from which deposit types?

• A. Alluvial only
• B. Alluvial, pipe and marine deposits
• C. Bedrock kimberlite only
• D. Marine deposits only

Answer: (B)

Diamonds are found in a range of deposit types, not just one kind. They originate in kimberlite pipes in the bedrock, which are the primary sources where diamonds crystallize and stay embedded in the host rock. But once they are liberated, diamonds can be transported by rivers and streams and accumulate in alluvial (placer) deposits, which are a major way diamonds are mined in many regions. They can also end up in marine deposits along coastlines and offshore, where diamonds are recovered from the seabed. Because Africa has substantial occurrences in all three environments—alluvial, pipe (kimberlite), and marine deposits—the best statement is that diamonds are recovered from alluvial, pipe, and marine deposits. The other options are too narrow, listing only one deposit type and overlooking the others.

Diamonds are found in a range of deposit types, not just one kind. They originate in kimberlite pipes in the bedrock, which are the primary sources where diamonds crystallize and stay embedded in the host rock. But once they are liberated, diamonds can be transported by rivers and streams and accumulate in alluvial (placer) deposits, which are a major way diamonds are mined in many regions. They can also end up in marine deposits along coastlines and offshore, where diamonds are recovered from the seabed. Because Africa has substantial occurrences in all three environments—alluvial, pipe (kimberlite), and marine deposits—the best statement is that diamonds are recovered from alluvial, pipe, and marine deposits. The other options are too narrow, listing only one deposit type and overlooking the others.