How to Read Placer Deposits: Understanding Paystreaks, Flowlines & Bedrock

Introduction

Placer gold is never random. It moves with water, settles by weight, and accumulates where flow energy drops. Reading a placer deposit means understanding how water sorted the material and where gold was forced to rest.

Once you learn to see paystreaks and flowlines, you can predict gold concentration instead of hoping you hit it by chance.

Key Points

Paystreaks follow energy breaks

A paystreak is a ribbon of concentrated heavies where the river slows just enough for gold to drop out. Inside bends, boulder shadows, and the downstream side of bedrock shelves are common energy breaks.

On a gravel bar, the paystreak often sits near the waterline on the inside bend, then angles downstream toward the tail-out where the channel narrows.

Flowlines show how water carries heavies

Flowlines are the invisible paths water takes around obstructions. Fine gold rides the water until it meets a low-pressure zone behind a boulder or a drop where the river widens. Follow those flowlines and you follow the gold.

Look for aligned cobbles or streaks of black sand that trace the path of heavier material. These are visual hints that the flow carried heavy minerals through that line.

Bedrock is the ultimate trap

Gold hugs bedrock because it cannot sink further. Cracks, crevices, and rough bedrock textures act like natural riffles. In Oregon, basalt and bedded sandstone often hold fine gold in shallow cracks.

Where bedrock is smooth, gold may slide to the next irregularity. Where it is fractured, gold can hide in tight seams that require careful cleaning.

Layering reveals flood history

Placer deposits often stack in layers from seasonal floods. Coarse gravels can mark high-energy events, while fine sands indicate slower flows. Gold is commonly trapped at the base of a flood layer, right above a compact clay or bedrock surface.

Dig and pan each layer separately to find the most productive horizon. When the gold drops off, you know you moved past the pay layer.

Tips

• Map your test pans along a bar to see the paystreak direction.
• Pan black sand streaks and follow the strongest line upstream.
• Probe for bedrock depth with a bar before committing to deep digging.
• Clean bedrock cracks with a crevice tool and finish pan.
• Note the height of the deposit above current water to identify old channels.

Conclusion

Reading placer deposits turns prospecting into a repeatable process. Study flowlines, paystreaks, and bedrock traps, then use that knowledge to guide your sampling. When you can predict where gold should be, you spend less time moving sterile gravel and more time recovering the good stuff.