What Secrets Does the Usselo Horizon in Dutch Moors Hold?

[Andre]

The Usselo horizon is a well known dark sandy or peat layer extending from west to central Europe. It's from Allerod age and it's described well here by some leading Dutch researchers. Unfortunately the nestor of Dutch Palaeobotany and Palynology reseach -specialist on the Usselo horizon - diseased last year.

Anyway, so we went on expedition to a well known moor, hunting for the Usselo horizon and we found this:

This was one of the last pictures taken -after sampling- but with the camera exactly horizontal so that the inclination can be measured accurately.

The layer is about 60 mm thick at the highest point but only 20mm at the lowest point. Detail here:

The layers are predominantly sandy but more dense, likely mixed with clay (loam). The nature of the dark brown color is unclear at the moment.

Anyway the usselo horizon is usually horizontal obviously and not layered (stratified), so what is it?

 

[Nik_2213]

Is that dune-sand, so aeolian ??

 

[Andre]

River sand actually; mostly delivered by the Rhine river towards the delta of the low countries where it became aeolian. The Usselo Horizon splits up the "younger cover sand I" and II. See this

Note that the younger cover sand I below the Usselo horzion is slightly paler in color. That can also be seen here, about 100 feet from that location, showing the horizon more typically.

But also here, and this site is about 100 miles to the north

 

[NileQueen]

Another source area for the coversands besides the Rhine Meuse, is the basin of the North Sea before it infilled.

 

[Alpha Male]

It's the Younger Dryas Boundary.

 

[NileQueen]

Hi Alpha Male,

Yes I do think it is the YDB. Have you seen Annelies van Hoesel's paper on Usselo horizons and nanodiamonds?

 

[billiards]

Hi Andre, I haven't read the papers but black usually means anoxic (low oxygen) conditions.

 

[NileQueen]

Hi billiards, You cannot generalize to anoxia here. These are coversands and this is a charcoal and organic-rich horizon.