Saw a dredge working on the Cape Fear River last month and the sediment color was wild

It was pulling up this bright orange clay, not the usual gray muck. Anyone know what causes that specific color in riverbeds?

3 comments

3 Comments

olivia_hernandez2mo ago

Could that orange color be from iron oxide in the clay layers?

holly_price2mo ago

Yeah, Olivia's totally right about the iron oxide. I saw the same thing last summer when they were dredging the Neuse River near New Bern. That orange clay layer was about three feet thick in some spots. It's basically rust in the soil from old deposits that get exposed when they dig. Looks crazy against the normal dark river mud.

finleyl5520d ago

Hang on, is it really just old iron deposits though? I live down near Morehead City and we get that same orange color in our yard every time it rains heavy. I've talked to a few guys from the geology department at UNC and they said a lot of that orange is actually from pyrite getting exposed to air, which turns into sulfuric acid and then binds with the iron. That's why you get that weird sulfur smell sometimes near the dredge piles, not just rusty dirt.