OK,
The thought on Ice Age processes at work here goes something like this. At the end of a cold period during a frozen period—not necessarily the last one—iron (Fe) precipitated-out due to a moisture interphase. That oxidized (rusted) iron accumulated at a place where there was a soil textural change, maybe at something like a frozen/unfrozen boundary. That in layman's terms is how soil scientist Professor Chien-Lu Ping in Alaska suggested to me the described process could have occurred.
An old Professor at Rutgers, soil scientist John Tedrow, noted similar iron-stain banding in the polar deserts of Antarctica, usually just beneath gravels that made up desert pavement.
Manumuskin, you are very observant. The reason why the pink material outcrops in patches may be related to the prior presence of modified frost cracks left over from permafrost, sand wedges that deformed into pocket-shaped gully channels as the ground thawed at the end of a very cold period. The gullies acted as sinks that collected precipitated iron, and they rhythmically outcrop across a pit wall.
The reason the modified-wedge infill pink material is dry and flakey has to do with the former presence of segregated ice lenses. In simplified language, thin layers of ground ice heaved and moved with soil freeze and thaw in cycles. The actual physics involved are more complex than explained, which involves heat flow resulting in moisture migration along a thermodynamic gradient.
Some of the clay-like material may actually be fine silt, windblown desert dust called loess. Now, to test that one you are going to have to do something brave; chew on a plug of the pink stuff. If you don’t feel any grit between your teeth, then it’s clay. If you can feel grit between you teeth, it’s silt. I know my methodology sounds like something from a Cheech & Chong skit, but this really is how it’s done in the field. Besides, eating dirt is good for you; Tedrow lived to 97.
An abstract is unavailable.
journals.lww.com
Cheers!
S-M
