Question

Match the magma series in Column 1 to the geological settings in Column 2.

• A. P-i; Q-iv; R-iii; S-ii
• B. P-ii; Q-iv; R-iii; S-i
• C. P-i; Q-i; R-iii; S-iv
• D. P-iv; R-ii; Q-i; S-iii

Hint:

Alkaline and shoshonite magmas are generally associated with oceanic intraplate settings, while calc-alkaline and tholeiitic magmas are found at convergent plate boundaries or back arcs.

Answer 1

The Correct Option is C

Step 1: Link each magma series to a setting.
Alkaline and shoshonite magmas form in within plate or oceanic island type settings. Calc alkaline magma forms at convergent margins above subduction. Tholeiitic arc magma forms in the back arc region.

Step 2: Place P and Q.
The alkaline series P and the shoshonite series Q both tie to the oceanic intraplate setting, so each takes (i).

Step 3: Place R.
The calc alkaline series R belongs to the convergent plate margin, so R takes (iii).

Step 4: Place S.
The tholeiitic series S sits in the back arc, so S takes (iv).

Step 5: Combine.
The full match reads P-i, Q-i, R-iii, S-iv.
\[ \boxed{\text{P-i; Q-i; R-iii; S-iv}} \]