Loess

Wind and water. Water takes it away quickly - faster than any other kind of soil.

Petersen wracked his brains trying to figure out how they were formed - slow comet particle impact, 4th dimension, but that does not explain the snail shells. Perhaps very large tornado or water spout?

for a guy who likes a little more clay content in his soil the Loes is not your friend. Iowa, central Illinois and points between.

In the first image in the thread, there is a landscape with erosional features such as 'gulley' and these are subject to 'valley fill'. From an aeolian formation mechanism perspective, the loess would effectively be raining fine soil dust down onto a landscape. The setting for this would have to be generally dry for the dust to form, but there is no requirement for the entire landscape to be devoid of water. I suggest the snail shells and larger clasts are the result of alternative erosional mechanisms: glacial / fluvial and their environments (see Fig 3 here). The angularity of clasts is reduced with exposure to the erosional agents. At or close to the source of the material and the point of entry even fluvial sediment can be highly angular.

ETA


Evidence for a windblown origin of loess
In order to explore the Neogene evolution of East Asian winter monsoon circulation, grain-size analysis was conducted on the Neogene Sikouzi section, Guyuan, Ningxia, China, a relatively monsoon-sensitive region. The results show that most of the particles are fine, the sand-bearing samples (median grain size [Md] >63 μm) are less than 6.4%, and that all the grain-size distribution curves of representative samples have a similar pattern to those of eolian dust sediments on the Chinese Loess Plateau. Rare earth element (REE) patterns of eight samples from the Sikouzi section are all characterized by light (L) REE enrichments, relatively flat heavy (H) REE patterns, and slight negative Eu anomalies, similar to those of loess and the average upper continental crust. These lines of evidence point to a windblown origin of the Sikouzi fine sediments.
source

Fluvial role in loess deposition
Rivers are essential for loess deposit formation. River systems which relate directly to loess deposit formation include the Danube and the Rhine; the Mississippi and the Missouri; the Thames and the Medway; the Indus, Ganges and Brahmaputra; the Dnepr, Don and Volga; the Clutha, Mataura and Rakaia—New Zealand rivers; the Yellow River; rivers in South America; Siberian rivers (flowing north); the Odra and the Wisla (between the mountains and the ice); the Syr-Darya and Amu-Darya (into the desert)
source

Role of fluvial transport agents for loess in England
A complex series of events in the Weald
loess trap causes a concentration of loess material by rivers flowing through various gaps in
the Downs. The Thames provides loessic estuarine deposits, and the Pegwell Bay loess was
a feature of the Stour. South coast accumulations are related to rivers flowing south through
Downs gaps, such as the Adur and the Arun.
source

Loess is not necessarily simply aeolian
The ‘known’ distribution of loess in the UK cannot be accounted for under simple aeolian transportation and dumping of silt sized material, its distribution is too sporadic. Therefore the distribution is controlled by the geomorphic surroundings, processes and even in some cases several phases of reworking and redistribution
source


Periglacial setting of loess
On the Yorkshire Wolds the loess was deposited before the ice reached its extreme limit, as it is incorporated in a chalky, flinty head beneath the till.
source

The role of freezing / freeze-thaw / cryoturbation
New sedimentological evidence is presented for phases of accretion with two distinct units, a calcareous brickearth exhibiting periglacial cryoturbation
source

Role of reworking of loess
Most loess has been modified to some degree by local reworking, bioturbation and syn-depositional weathering, but a process of ‘loessification’ is not necessary for a dust deposit to qualify as loess. The terms ‘primary loess’ and ‘secondary loess’ have previously been used to described wind-deposited loess and redeposited loess, respectively, but it is more accurate to describe material reworked and redeposited by non-aeolian processes as ‘loess-derived colluvium’ or ‘loess-derived alluvium’.
source

Influences on Chinese loess
the Chinese Loess Plateau has evolved as a more dynamic landform than previous thought, where wind deflation, fluvial input, lateral transport, and accumulation of sediment are equally important
source

Lacustrine Himalayan loess
In the Kashmir valley the Quaternary geological record is preserved in the form of exposed Karewas (ancient lake beds), capped by loess.
source

Simplicity ... ahhh!

metalsmith, Great information! - But it does not account for the long capillary tubes, empty spaces, odd clay masses, nor the snails.

What I like about the waterspout idea is water between the particles that later dried out accounts for the spaces. Air bubbles rising accounts for the tubes, mud balls slammed together in the wind accounts for the odd clay found. Oh, and also the snails.

It does not account for the huge volume.

metalsmith, I've also considered very heavy windstorms that convert to torrential rains.

We are on the verge of talking about lahars.

Connect this thread to
forum.rocktumblinghobby.com/post/921993

The hills around Phoenix appear to be covered with a thick mud like loess. Most odd.

Wow!! now this is getting thick
as the melted mud crust of the Papago's

I like it

Recall that I mentioned about the government land?
No access! National armory?
hhhhmmmmmm……

Unfortunately what buried at Barnes Butte in Phoenix
is classified. Top secret!
Even Petersen couldn’t get in to inspect the melt!

Perhaps I’ll try….

Wrong Barnes Butte, metalsmith.  That one is located in Prineville, OR.

I think the answer to age of the buttes is bound up with erosion issue/
what I can't understand is why the buttes are granite breccia's ?
why not just solid granite like most mountains ?