Question

Match the microstructures in Group-I with their characteristics in Group-II. Group-I Group-II

	Group-I		Group-II
P	Core-mantle	1	Radiating fibrous aggregate of K-feldspar with or without quartz
Q	Decussate	2	Large strained mineral grains surrounded by fine-grained, recrystallized grains
R	Spherulite	3	Inclusion trails in a porphyroblast curves into the matrix foliation by developing concave outward pattern
S	Millipede	4	Randomly oriented mineral grains dominated by crystal faces, such as in sheet silicates

• A. P-2, Q-3, R-4, S-1
• B. P-3, Q-4, R-1, S-2
• C. P-2, Q-4, R-1, S-3
• D. P-4, Q-2, R-3, S-1

Hint:

- Core–mantle → Recrystallization around strained grains.
- Decussate → Random sheet silicate grains.
- Spherulite → Radiating fibrous aggregates.
- Millipede → Inclusion trails bending into matrix foliation.

Answer 1

The Correct Option is C

Step 1: Recall each microstructure.
- Core–mantle structure: Large strained mineral grains (core) surrounded by fine recrystallized grains (mantle). → (2).
- Decussate texture: Randomly oriented mineral grains, common in sheet silicates (micas, chlorite). → (4).
- Spherulite: Radiating fibrous aggregates of minerals such as K-feldspar and quartz. → (1).
- Millipede structure: Inclusion trails in porphyroblasts curving into matrix foliation forming concave outward patterns. → (3). Step 2: Match with options.
\[ P \to 2, \quad Q \to 4, \quad R \to 1, \quad S \to 3 \] Final Answer: \[ \boxed{\text{(C) P-2, Q-4, R-1, S-3}} \]