In message 27, Hangdawg13 quoted Walt Brown as stating:
"This soil has been identified as loess103 (a German term,
pronounced "LERSE")."
With this first sentence, Walt Brown shows a distinct lack of knowledge of loess. According to the way that geologists and pedologists define "soil", loess is not a "soil". Loess isn't a weathering horizon developed from the ground's surface. Thus, loess isn't a "soil" even though the modern soil is often developed in it and loess can contain fossil soils called "paleosols", buried within it. Loess is a specific type of sediment consisting of well-sorted, often calcareous, unstratified silt that, although weakly coherent, is strong enough to stand in steep or vertical faces. Technically speaking loess is sediment, not a soil as Walt Brown incorrectly stated above.
Hangdawg13 quoted Walt Brown as stating:
"Little is known about its origin."
As far as conventional Earth Scientists in general are concerned, the origin of loess has been well established for many decades on basis of many lines of evidence and observations. The lack of any mystery about the origin of loess can be seen in the abundance of evidence found published in the scientific literature. For example, the detail to which conventional geologists understand the origin of loess is illustrated by the collection of papers concerning the "Loess and the Dust Indicators and Records of Terrestrial and Marine Palaeoenvironments (DIRTMAP) database", which are found in Volume 22, Issues 18-19, September 2003, of Quaternary Science Reviews. The table of contents for this issue can be found by clicking the "Volume 22, Issues 18-19, Pages 1813-2052 (September 2003)" link at:
http://www.sciencedirect.com/science/journal/02773791
The abundance of evidence confirming the eolian origin of loess can be found in many published books on Quaternary Geology such as
1. Porter, S. C., Atwater, B. F., and Porter, S. C., 2003, The
Quaternary Period in the United States, Elsiever, New York.
and
2. Smalley, I. J., ed, 1975, Loess; lithology and genesis.
Benchmark Papers in Geology, no. 26, Dowden, Hutchinson and
Ross, Inc., Stroudsburg, Pensylvania.
The only mystery here is how a person, who claims to have research in any detail the matter of the origin of loess in any detail and claim that little is known about loess and that its origin can still be considered a mystery.
Hangdawg13 quoted Walt Brown as stating:
"Most believe it is a windblown deposit spread under cold,
glacial conditions over huge regions of the earth."
The fact of the matter is that conventional geologists recognize at least three types of loess, glacial, desert, and volcanic loess. In glacial loess, the ultimate source of loess is silt-size sediment, called "rock flour" produced by the grinding rock by ice sheets. As observed, in modern ice sheets and glaciers, the rock flour is carried down streams and rivers carrying meltwater from the glaciers and deposited on their floodplain. As also observed in modern environments, under the right conditions, wind will erode the rock flour from the dried floodplain of a meltwater river and dump it on the uplands adjacent to the river valley to form loess.
However, geologists also recognize nonglacial desert loess. It consists of silt eroded from large dune fields and dry lakes found in deserts and blown downwind of the desert areas where it settles out to accumulate as loess. The loess covering the Loess Plateau of China is an example of a desert loess The silt comprising it was derived from silt eroded from the deserts and gobis (desolate depressions filled with dry lake beds) of Central Asia northwest of the Chinese Loess Pateau. The source of the Chinese Loess is clearly shown by the decrease in grain size and overall thickness of loess deposits within the Loess Plateau downwind from the downwind edges of the Ordos Desert as illustrated by a figure in Vandenberghe et al. (1997). Along the edges of the Ordos Desert, desert sands gradually grade downwind into sandy loess. Further downwind, the sandy loess grades laterally into loess and finally into clayey loess.
The loess of the Argentina Pampas represents third, nonglacial, type of loess. Detailed studies of it have shown, beyond a shadow of a doubt, that it consists of volcanic ash blown eastward from volcanoes in the Andes Mountains. The abundant evidence supporting this interpretation is discussed and documented in detail by Clapperton (1993) and Zarate (2003). In fact, historic volcanic eruption have continued to add more sediments to pile of volcanic loess that underlie the Pampas of Argentina.
References Cited:
Clapperton, C., 1993, Quaternary geology and geomorphology of
South America. Elsevier Science Publishers B. V., Amsterdam.
Vandenberghe, J., Zhisheng, A., Nugteren, G., and others, 1997.
New absolute time scale for the Quaternary climate in the Chinese
loess region by grain-size analysis. Geology. vol. 25, no. 1,
pp. 35-38.
Zarate, M. A., 2003, Loess of southern South America. Quaternary
Science Reviews. vol. 22, no. 18-19, pp. 1987-2006.
An interesting web page:
Dust if You Must
Loess is more
Hangdawg13 quoted Walt Brown as stating:
"However, Siberia was scarcely glaciated, and normal winds would
deposit loess too slowly to protect so many frozen animals from
predators."
Given that the mummified remains of mammoths and other animal aren't found in loess deposits, this is a totally meaningless argument. It also demonstrates that Walt Brown didn't bother to do enough research to find out that thick, continuous blankets of loess only occur in southern Siberia, far south of the areas in which ice complexes (yedomas) are found.
Hangdawg13 quoted Walt Brown as stating:
"Loess often blankets formerly glaciated regions, such as Wisconsin, Illinois, Iowa, Kansas, and Alaska."
In the real world, formerly glaciated regions areas are areas less likely to have a blanket of loess. Typically, thick blankets of loess occur in areas downwind of major desert regions, the uplands adjacent to major meltwater drainage systems, close to mountain ice caps, and, in case of southern South America, areas downwind of major volcanic chains. Formerly glaciated areas are less likely to be blanketed by loess, because ice sheets covered glaciated areas during the main period of loess accumulation. The ultimate source of the loess was sediments removed from these areas by the ice sheets. Loess blanket typically blanketed a former glaciated area only if it was glaciated during a glacial epoch older than the one glacial during which the loess accumulated. This can be seen in figures showing the distribution of loess in:
Bettis, A. E., III , Muhs, D. R., Roberts, H. M., and Wintle,
A. G., 2003, Last Glacial loess in the conterminous USA.
Quaternary Science Reviews. vol. 22, no. 18-19, pp. 1907-1946.
Hangdawg13 quoted Walt Brown as stating:
"It lacks internal layering (stratification)"
(Walt Brown has his facts correct, for once.) The massive nature of loess is expected because plants and animals are churning the upper surface of the ground much faster than the loess is accumulating and, thus, preventing internal stratification from forming. If loess accumulation either cease or greatly slows down, then weathering and biologic processes can modify the loess below the stable ground surface enough to form an recognizable soil horizon. When loess accumulation begins again, this soil often is buried and preserved as a "fossil soil", paleosols.
Some examples of fossil soils, palesols, in loess are:
Loess-Paleosol Complex
SOIL SCIENCE 100
Paleoclimate Investigations
This web site has moved
A good documented discussion of well-documented palesols preserved in loess can be found in:
Muhs, D. R., Ager, T. A., Bettis, E. A., III, McGeehin, J.,
Been, J. M., Beget, J. E., Pavich, M. J., Stafford, T. W.,
Jr., and Stevens, D.-A. S. P., 2003,Stratigraphy and
palaeoclimatic significance of Late Quaternary loess-
palaeosol sequences of the Last Interglacial-Glacial cycle
in central Alaska. Quaternary Science Reviews. vol. 22,
no. 18-19, pp. 1947-1986
Hangdawg13 quoted Walt Brown as stating:
"and is found at all elevations-from just above sea level to
hillsides at 8,000 feet elevation."
This focus on elevation completely ignores an important aspect of loess, which is it lateral distribution. If a person looks at the regional distribution of loess, he or she will find that the blanket is always thickess adjacent to its source. Downwind of a source, whether it is a meltwater river or desert, the thickness of the loess blanket decreases in thickness. In addition, not only does the thickness of the loess decrease away from its source, but also the average grain size of the sediment comprising the loess decreases downwind of, away from it source. The decrease in thickness and grain size is perfectly explained by the wind-blown model of loess as described by numerous peer-reviewed papers, including ones found in:
Smalley, I. J., ed, 1975, Loess; lithology and genesis.
Benchmark Papers in Geology, no. 26, Dowden, Hutchinson and
Ross, Inc., Stroudsburg, Pensylvania.
Hangdawg13 quoted Walt Brown as stating:
"Because loess is at many elevations and its tiny particles are
not rounded by thousands of years of exposure to water and wind,
some have proposed that loess came recently from outer space.104"
Again, in the above statement, Walt Brown shows a remarkable lack of knowledge of how conventional geologists explain the origin of loess. Again, he is completely unaware of the fact that the distribution of loess in terms of elevation is completely consistent with a wind-blown origin. It is also a completely insignificant aspect of how conventional geologists explain the origin of loess. The lateral distribution of the thickness and grain size of loess relative to major deserts and river systems is far more important than relative distribution in elevation. In fact, there is nothing about the elevations of known loess deposits relative to their source areas that is inconsistent with the wind-blown origin of loess.
The part of the statement about loess not being rounded by "thousands of years of exposure to water and wind" is another example of a remarkable lack of knowledge on the part of Walt Brown concerning basic principles of geology. It is basic knowledge among geologists, because of the small size and mass of silt particles, thousands of years of "exposure" and transport of them by either water or wind would have very little effect on their roundness. Conventional geologists would regard the lack of rounding in silt particles after thousand, even millions of years of "exposure" and episode transport, as being neither unusual nor anomalous observation either requiring an extraterrestrial explanation or inconsistent with the wind-blown origin of loess.
Walt Brown is completely wrong in implying that the conventional theory about the origin of loess requires that the silt, which compose it is transported and "exposed" for thousands of years before being deposited as loess. In fact, conventional theories would argue that the silt particles are moved about for a period of time as short as a few months before accumulating as loess. In terms of glacial loess, the silt is released by the melting of the glacier as rock flour during the spring or summer. It is transported down a river over a period of few days to months and dumped on the floodplain by spring or summer flooding. Then the floodplain dries up as the glaciers freeze-up for the winter and meltwater from them ceases to flow for several months. During the fall and winter, wind blowing across the floodplain erodes surface silt and carries them above and outside of the floodplain where silt eventually settles on the upland surfaces adjacent to the valley walls of the floodplain.
If a person checks out the citation for footnote "104" that Walt Brown cited as having proposed that loess came from outer space, he or she would find these citations to be:
1. "John B. Penniston, "Note on the Origin of Loess," Popular
Astronomy , Vol. 39, 1931, pp. 429-430" and
2." John B. Penniston, "Additional Note on the Origin of Loess,"
Popular Astronomy , Vol. 51, 1943, pp. 170-172"
Both of the references are antiquated papers that are 61 to 73 years old and published in popular, non-peer reviewed magazine. Neither of these articles are serious scientific papers worth the attention that Walt Brown gives them. In fact, the idea of extraterrestial origin of loess has not gotten any support in conventional circles and surfaced only in one book, that I know of, published in the realm of alternative science along with books about crop circles, perpetual motion machines, and ghosts.
Hangdawg13 quoted Walt Brown as stating:
"Loess, a fertile soil rich in carbonates, has a yellow
tinge caused by the oxidation of iron-bearing minerals
since it was deposited.105 China's Yellow River and Yellow
Sea are so named because of the loess suspended in them."
Here, Walt Brown cites a 1974 undergraduate geology textbook. In writing for the lay, non-geologist student, the author has confused the technical distinctions between soil and sediments. Instead of citing the latest scientific journals for his information, Walt Brown quote mines now antiquated textbook for his own purposes.
Hangdawg13 asked:
"Why is there an apparent relationship between frozen
mammoths, yedomas, and loess?"
Given that this "apparent relationship", which I will elaborate on in another post, exists only in Walt Brown's imagination, no explanation is needed for it. For example, ice complexes, for which "yedomas" is somewhat of an antiquate term, lack any association with the occurrence of loess deposits. Yedomas are a specific type of permafrost that forms in areas where precipitation was too low to form ice sheets and characterized by extremely cold annual temperatures regardless of whether loess blankets the surface of an area or not. For example, the best documented ice complex, called "Mamonontovy Khayata" (Mammoth Mountain), which lies near the western shore of the Laptev Sea, is composed entirely of fine sand overlain by peat. Neither muck nor loess is present either within it or within its vicinity. Furthermore, loess occurs only as a thick, continuous blanket in an area of southern Siberia that is completely devoid of yedomas and far south of where they occur. There is no consistent association between the presence of loess and occurrence of yedomas (ice complexes).
Hangdawg13, commented:
"I don't think the landslide explanation accounts for all of these facts."
In terms of loess, this is a meaningless complaint because neither any other geologist nor I use "landslides" to explain the formation of loess.
The problem here is that you, as Walt Brown has hopelessly done, completely confused loess with "Muck". According to one definitions of "muck", muck as highly decomposed organic material containing a certain percentage of silt, loess and "muck" are two completely different types of sediment of different origin. Another definition of "muck" defines it as unconsolidated ice-rich silt. In thsi case, loess can be classified as "muck", but only if permafrost has developed in it. Even under this definition of loess, it is dishonest to classify the vast majority of loesses, i.e. the loesses of China, Mississippi River Valley, the Midwest, Washington state, Argentina, and so forth, as "muck", because these loesses all lack ice (permafrost). In addition, under this definition, silt of other origins, i.e. floodplain, slopewash, lake, marine, and other deposits, are also classified as "muck". Thus, it is impossible, without additional information, to know whether this type of "muck" consists of loess or some other type of silt.
The specific definition of "muck", for which the landslide origin was discussed, is the "muck" that various catastrophists define as containing "Trees and animals, layers of peat and mosses, twisted and mangled together like some giant mixer had jumbled them some 10,000 years ago, and then froze them into a solid mass". (Please note that loess doesn't fit the description of this type of "muck".)
This types of "muck" is only a surficial deposit created by landslides, solifluction lobes, debris flows, various periglacial processes and so forth. The details about the origin of this Muck" is given in my previous posts. For example, "Arctic Muck", Message 187 of Wyatt's Museum and the shape of Noah's Ark at:
http://
EvC Forum: Wyatt's Museum and the shape of Noah's Ark -->
EvC Forum: Wyatt's Museum and the shape of Noah's Ark
Please note, that landslides are not the only process that create this type of muck as Hangdawg13 mistakenly implies. Various periglacial processes, including the formation of thermal karst in permafrost, can create this type of muck. In fact, thermal karst easily can create pools or bogs of semifluid muck (mud) on flat surfaces large and deep enough to trap large mammals such as horses and mammoths.
Also, "muck" has other definitions that different people use. Depending on what definition a person, uses, the specific type of "muck" being discussed may or may not have been created by any number of processes. Before a person can dismiss a specific process as having created "muck", a person needs to specify the specific definition of "muck" they are using.
Hangdawg13 asked:
"BTW what are your beliefs on the origin of Loess?"
I don't "believe" in a specific origin of loess as the matter of its origin isn't a religious or personal matter dependent on faith or personal intuition. Instead, I accept the wind-blown origin of loess as an explanation for its origin based on data collected from field observations and laboratory analyses that show that the lateral distribution, stratigraphy, chemistry, and physical characteristics, i.e. grain-size distributions, of loess are all completely explainable with such an origin.
Accepting the wind-blown origin of loess as fact has nothing to do with personal belief, but rather the honest, scientific evaluation of hard, verifiable physical evidence and field observations along with credible published laboratory data.
Yours,
Bill
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