red rocks

[Grayjay]

One the shore of the East Branch and also on Cedar Brook, there are boulders with a reddish tinge where high water would hit them. My first assumption was that it was an algae, but a friend suggested it could be iron. Or it could be both. Does anybody know?

 

[dr_wu002]

One the shore of the East Branch and also on Cedar Brook, there are boulders with a reddish tinge where high water would hit them. My first assumption was that it was an algae, but a friend suggested it could be iron. Or it could be both. Does anybody know?

The bottom of the Arrow Slide on Hancock, the rocks are all deep red. It's blood from dinosaurs that got mixed in with the rock.

-Dr. Wu

 

[Grayjay]

The bottom of the Arrow Slide on Hancock, the rocks are all deep red. It's blood from dinosaurs that got mixed in with the rock.

-Dr. Wu

I might say that since it is off a river, then this is a seperate phenomenon, whether dinosaurs blood or VFTT members painting rocks. But a little more than half way up Ice Gulch, there are also red rocks similar to the ones on the East Granch and Cedar Brook. obviously there is no high water presently there. Do any of you left brained scientists know what the red is?

 

[dr_wu002]

I might say that since it is off a river, then this is a seperate phenomenon, whether dinosaurs blood or VFTT members painting rocks. But a little more than half way up Ice Gulch, there are also red rocks similar to the ones on the East Granch and Cedar Brook. obviously there is no high water presently there. Do any of you left brained scientists know what the red is?

Iron.

-Dr. Wu

 

[David Metsky]

Iron.

Yup, red rocks are usually iron.

 

[Bob]

Iron.

-Dr. Wu

why only certain rocks ?...these rocks lay right next to each other, so are subject to the same water level. Some have the red, the ones right next to them don't.

 

[Grayjay]

Thanks. I was going to send a photo of the ones on Cedar Brook, but I haven't figured out how to put pictures on here. If anyone has the time to tell me step by step (again), you could do it here or send me a pm.

 

[dr_wu002]

why only certain rocks ?...these rocks lay right next to each other, so are subject to the same water level. Some have the red, the ones right next to them don't.

The rocks aren't stained with iron, they're formed with the iron in them. I think it's pyrite. Dr. D (or my wife who is also a geologist) would know. They get mixed in with other rocks because they were moved there by glaciers, rock slides, wind I guess...

-Dr. Wu

 

[Grayjay]

Thanks Wu, but often, as the case with Cedar Brook, the upstream side is dark red, and the downstream side untouched, Also, it is obvious that the red is only on the surface, and not part of the nature of the rock. That is why I first thought of algae.

 

[dug]

same rock type, one red on one side, one not on the other side, would be more toward algae.

different rocks do react differently to iron.

 

[DougPaul]

The red coloration of rocks is often due to iron oxide.

Doug

 

[NeoAkela]

I saw the same thing on the rocks along the long slide that goes up the western side of the ridge between Liberty and Haystack. It looked like someone had painted all the tops with red paint. Thank you for that information!

 

[NH_Mtn_Hiker]

Red Rock Ravine has a few of those rocks as well