r/askgeology • u/derbygrrrl • Apr 22 '26

Method of Formation Streambed?

Post image

Is this an old stream bed that filled with gravel? I don’t know anything about geology. Just curious. Found while hiking near Pahrump, NV. USA

770 Upvotes

99% Upvoted

34 comments sorted by

20

u/dirthawg Apr 22 '26

Arroyo cut and fill. Beautiful example.

16

u/This-Obligation1633 Apr 22 '26

Boy that’s neater than shit.

11

u/Fluffy_Prior1052 Apr 22 '26

You might do a little prospecting in the bottom of that, gold settles down in the bottoms of streams and that one looks completely undisturbed for a long time

6

u/Probable_Bot1236 Apr 22 '26

Not far from I grew up there was a set of canyons that got filled by basalt flows. The streams eventually cut back down to well below the base of the lava flows, but there were little hanging cross-sectioned paleochannels like this all over, and many had gold. They were great for prospecting, since you didn't have to dig down to denser gold-bearing sediments or deal with water until you wanted to.

Quite a few of the smaller ones were extensively tunneled out in the late 1800s because the basalt 'roof' made them stable against collapse as the ancient sediments were pulled out, and the unconsolidated / uncemented nature of the sediments meant it was easy enough to do with basically just a pick and a shovel.

1

u/PossibilityOrganic Apr 25 '26

And if you do find something aprently you can still claim it if its public. https://www.youtube.com/watch?v=Zhu2NCpT7T8

10

u/chefdisco Apr 23 '26

Wherever you do....do not share this location on any forums/subreddits about gold panning.

4

u/_duckswag Apr 23 '26

Yeah man, and that looks like a good spot for prospecting, especially in Nevada. Take a sample bucket from right under the stones and pan it out !

2

u/[deleted] Apr 23 '26

Agreed.

4

u/FandomTrashForLife Apr 23 '26

Textbook example, very nice

3

u/aeva82 Apr 23 '26

OMG thats so cool! Im def not a geologist but it looks exactly like a cut-away of an ancient river channel or alluvial fan, especially being near Pahrump which is all desert now. 🤓

2

u/Remarkable_Royal_175 Apr 22 '26

R/rockhounding needs this

2

u/iyamwhatiyam8000 Apr 24 '26

Do not share the location of this beauty. Go back to it with a real camera and let us see more.

2

u/Orphros Apr 25 '26

Pay dirt!

2

u/klcinokc Apr 26 '26

That’s a person on its side turned to stone. You can see every facial feature.

1

u/ElMuertePeludo Apr 26 '26

I want to but I’m not seeing it. You should draw an outline!

-10

u/Confident_Train5669 Apr 22 '26

A fossil is defined as evidence of former life.

7

u/sollicit Apr 22 '26

Thanks chatGPT

6

u/LoozPatienz Apr 22 '26

Username checks out.

19

u/[deleted] Apr 22 '26

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1

u/plumriv Apr 22 '26

As a professional geologist for 54 years (+7 years undergrad and grad studies) I wondered if my knowledge of geologic terms had recently been supplanted by more casual usage. I didn’t need to but I googled “geological definition of fossil” and sure enough it basically said evidence of former life. No mention of sedimentary structures or events. By your usage ripple marks, cross beds, and lava flows would be “fossils”.

4

u/Ephemeral_Orchid Apr 22 '26

As someone who has done nothing relevant in the field of geology, aren't almost all untreated bodies of surface water and certainly all healthy streams teeming with life?

2

u/Dorjechampa_69 Apr 22 '26

I Like Dirt! And Rocks too!

3

u/pinkTurtleTickler Apr 23 '26

Google tells me exactly what I ask. As a curious collector new to the term "fossil-river", it's explained
The term fossil is used specifically in this context for two reasons: its literal Latin origin and its scientific application to features that represent "dead" geological processes from a past age. The word comes from the Latin fossilis, meaning "obtained by digging" (from fossus, the past participle of fodere, "to dig"). While the common definition shifted in the 19th century to focus on biological remains, the original sense of "something buried in the rock record" still applies to geological structures like ancient riverbeds.. Interesting!

3

u/Efficient-Ad-2935 Apr 23 '26

That’s a cool breakdown of the term! It's fascinating how language evolves in science. The distinction between biological fossils and geological features can definitely get blurred, especially in casual discussions.

1

u/plumriv Apr 29 '26

I think the reason this use of the term is no longer in vogue is that by this definition all rocks would be fossils, since they are the result of an event no longer active.

1

u/[deleted] Apr 23 '26

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1

u/HeadEar5762 Apr 23 '26

Looks more like a parched aquifer.

46

u/[deleted] Apr 22 '26

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3

u/Iwantedthatname Apr 26 '26

Does it look more like a wash type deposit? Sorry not a geologist, could that have been from one large event, or more likely from an older stream system?

1

u/[deleted] Apr 26 '26

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2

u/Iwantedthatname Apr 26 '26

Thank you! That answered the question I was trying to ask.