Oakland Geology

I’ve shown you the ugly orange streambed just below the old McDonell pyrite mine. Farther downstream, little Leona Creek emerges from private backyards next to Mountain Boulevard at Twitter Court.

It’s still pretty orange here, from extremely small (colloidal) particles of iron oxide minerals that form as the acid drainage from the mine is neutralized. The creek enters a culvert here and disappears. Somewhere under the Warren Freeway, it joins Lion Creek on its way to the bay. Lion Creek appears next as Lake Aliso on the Mills College campus, and unless the lakebed is all orange too, the pollution has been fully neutralized by that point. As I’ve said before, the pollution looks awful, but without chemical tests we can’t tell if it’s poisonous. Iron oxides by themselves are not a great hazard.

This entry was posted on 17 August 2014 at 2:23 pm and is filed under Oakland streams and water, Quarries and mines. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.