Question

If P, Q, R, and S refer to Rainfall induced landslide, Bolide impact, Milankovitch cycle, and Supercontinent cycle, respectively, then which one of the following correctly represents the decreasing order of their duration?

• A. S, R, P, Q
• B. Q, P, R, S
• C. S, Q, P, R
• D. S, P, Q, R

Hint:

The supercontinent cycle spans hundreds of millions of years, while bolide impacts are instantaneous events. The Milankovitch cycle and rainfall-induced landslides lie in between.

Answer 1

The Correct Option is C

Step 1: Understanding the duration of each cycle.
- Supercontinent cycle (S): This cycle refers to the process of the formation and breakup of supercontinents, which typically spans hundreds of millions of years, making it the longest in duration.
- Milankovitch cycle (Q): This cycle is driven by the Earth's axial tilt, eccentricity, and precession, and has a duration ranging from tens of thousands to a few hundred thousand years. This is much shorter than the supercontinent cycle but still long compared to the other events.
- Rainfall-induced landslide (P): This is a short-term event that occurs on timescales of days to years, depending on the intensity of rainfall and other factors. It is the shortest duration in this comparison.
- Bolide impact (R): A bolide impact, caused by a large asteroid or comet striking Earth, is an instantaneous event that happens in a very short time frame. It is considered an extremely brief event in comparison to the others.

Step 2: Order of duration.
- Supercontinent cycle (S) has the longest duration (hundreds of millions of years).
- Milankovitch cycle (Q) follows, with a duration of tens of thousands to hundreds of thousands of years.
- Rainfall-induced landslides (P) have a duration in the order of years.
- Bolide impacts (R) are instantaneous events that occur in seconds to minutes.

Step 3: Conclusion.
The correct order of decreasing duration is: S (Supercontinent cycle), Q (Milankovitch cycle), P (Rainfall induced landslides), and R (Bolide impact). Hence, the correct answer is (C).
\[ \boxed{\text{S, Q, P, R}} \]