Question:medium
Which one of the following primary structures can be used for paleocurrent measurement?
Which one of the following primary structures can be used for paleocurrent measurement?
Show Hint
Flute casts always indicate flow direction — the pointed end faces upstream and the rounded end faces downstream.
Updated On: Jun 1, 2026
- Oscillation ripple
- Hummocky cross-strata
- Flute cast
- Load and flame structures
Show Solution
The Correct Option is C
Solution and Explanation
Step 1: What paleocurrent means.
Paleocurrent is just the old flow direction of water or wind that moved the sediment long ago. To read it, we need a structure that points clearly one way.
Step 2: Pick the test for a good marker.
A useful marker must have a fixed shape that records up flow and down flow. If a structure forms by back and forth motion, it cannot point one way.
Step 3: Check the wave and storm features.
Oscillation ripples come from waves that swing both ways, so they are symmetric and give no single direction. Hummocky cross strata form in storms with mixed flow, so they also fail.
Step 4: Check the soft sediment feature.
Load and flame structures form when heavy sand sinks into soft mud below. They tell us about density, not about current direction.
Step 5: Settle on the flute cast.
A flute cast is scooped out by a one way current. It has a deep pointed nose facing upstream and opens out downstream, so it shows flow direction at once.
\[ \boxed{\text{Flute cast}} \]
Paleocurrent is just the old flow direction of water or wind that moved the sediment long ago. To read it, we need a structure that points clearly one way.
Step 2: Pick the test for a good marker.
A useful marker must have a fixed shape that records up flow and down flow. If a structure forms by back and forth motion, it cannot point one way.
Step 3: Check the wave and storm features.
Oscillation ripples come from waves that swing both ways, so they are symmetric and give no single direction. Hummocky cross strata form in storms with mixed flow, so they also fail.
Step 4: Check the soft sediment feature.
Load and flame structures form when heavy sand sinks into soft mud below. They tell us about density, not about current direction.
Step 5: Settle on the flute cast.
A flute cast is scooped out by a one way current. It has a deep pointed nose facing upstream and opens out downstream, so it shows flow direction at once.
\[ \boxed{\text{Flute cast}} \]
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