Question

Choose the correct statement(s):

• A. Stratiform chromite deposits form by weathering of ultramafic rocks.
• B. Skarn deposits mostly form in calcareous host rocks in contact with felsic intrusives.
• C. Nickeliferous laterite is a type of placer deposit.
• D. Gold-bearing vein deposits can form from hydrothermal solutions.

Hint:

Skarn deposits form due to contact metamorphism, typically where igneous intrusions interact with sedimentary rocks, particularly limestones.

Answer 1

The Correct Option is B, D

Step 1: Analyzing the statements. 
- (A) Stratiform chromite deposits typically form in ultramafic rocks but not through weathering, so this statement is incorrect. 
- (B) Skarn deposits are indeed formed by the contact metamorphism of calcareous rocks with felsic intrusions, making this statement correct. 
- (C) Nickeliferous laterite is not a placer deposit; it forms from the weathering of ultramafic rocks, so this statement is incorrect. 
- (D) Gold-bearing vein deposits often form from hydrothermal solutions, making this statement correct. 
 

Step 2: Conclusion. 
The correct answers:

(B) Skarn deposits mostly form in calcareous host rocks in contact with felsic intrusives. 

(D) Gold-bearing vein deposits can form from hydrothermal solutions.