Origin Of Loess Research Articles

Three-stage collapsibility evolution of Malan loess in the Loess Plateau

Soil collapse forms a major hazard in large parts of Canada, the United States, Europe, China, and Africa, especially in the Loess Plateau of China. The Malan loess overlying the Loess Plateau with porosity and water sensitivity due to its typical wind-deposited characteristics, which also determines its collapsibility. Human activities continue to increase in the Loess Plateau underlain by collapsible soils, so that the hazards posed are increasing in both relative and absolute terms. The purpose of this paper was to reveal the collapsibility mechanism of Malan loess in the Loess Plateau by combining macro and micro research methods. The aim was to identify the internal and external factors affecting loess collapse from the origin of loess and to reconstruct the collapse process as a key to theory so as to enhance utilization and diminish hazard. Oedometer-collapse tests were used to explore the relationship between pressure, water content and loess collapsibility coefficient. Scanning electron microscopy (SEM) and computed tomography (CT) scanning tests were used to reveal the qualitative and quantitative characteristics of loess microstructure before and after the test, to comprehensively reproduce the loess collapsibility process. The results revealed the three-stage collapsibility evolution process of Malan loess. The weak connection mode and vertically distributed particles constitute the natural loess with metastable structure. Under the action of wetting and loading, the contact mode of soil particles changes, the large and medium pores are compressed, and the loess is transformed into unsaturated compacted structure before yielding pressure. The soil exhibited a saturated collapsed structure with the decrease of pore volume and the increase of soil particle cementation after structural yield stress. At the same time, it is determined that the structural yield stress of soil determines the peak value of collapsibility pressure.

Provenance and paleoenvironmental context of the Late Pleistocene thin aeolian silt mantles in southwestern Poland – A widespread parent material for soils

Thin loess deposits are widespread soil parent materials and important archives for paleoenvironmental reconstruction. The origin of loess in SW Poland is attributed to the Great Odra Valley (GOV), following the general concept that large rivers play a major role in regional silt supply. Yet, the precise provenance (glacier sources and/or local rocks) of silts, possibly deflated from dry GOV braided riverbeds, is not clear. Our study of thin and thick loess mantles in SW Poland for the first time indicates the provenance of thin loess based on mineralogical (MLA-SEM) and isotopic analyses (143Nd/144Nd, 87Sr/86Sr). Luminescence ages of five localities point to thin loess mantle formation during and shortly (23.0 to 17.7 ka yr) after the Last Glacial Maximum (LGM). Our isotopic data indicate that thin loess deposits in SW Poland are the mixtures of two main components – local Sudetic and Scandinavian, the latter delivered by the Fennoscandian ice sheet (FIS). Also, detailed analyses of heavy minerals show that a single mineral (e.g., hornblende) may come from both Sudetic and Scandinavian sources. This research highlights the role of the (Pleistocene) GOV in collecting and homogenizing materials, while supplying the region with fine particles to be deflated by paleowinds from open surfaces. Anomalies in mineralogy and isotopic composition are connected with influence of Sudetic mountain rivers and locally blowing silt material by katabatic winds. Regional grain size differentiation of thin loess mantles explains transport distance and altitude.

Origin of loess deposits in the North Tian Shan piedmont, Central Asia

Loess deposits are widely distributed along the mountain piedmonts of Central Asia. The transport processes and origins of Central Asian loess sediments remain poorly understood. Here we investigate the origin and formation of loess along the northern piedmont of the Tian Shan based on trace element (including rare earth element) ratios and multidimensional scaling analysis. Our results indicate that the loess has undergone weak chemical weathering. Using a selection of geochemical fingerprinting techniques based on Pearson correlation and Kruskal–Wallis H tests, we establish a genetic link between alluvial-proluvial fans/plains, deserts, and loess along the Tian Shan piedmont in northern Kyrgyzstan and southern Kazakhstan. The unsorted sediments on the piedmont slopes and alluvial-proluvial plains are common sources for both deserts and loess to the north of the Tian Shan. Dune sediments are not the main source of the fine-grained loess. Origin and formation of Central Asian loess is strongly dependent on local topographic context and wind dynamics. Only once loess provenance and formation has been understood across both space and time can reliable interpretations of palaeoclimatic proxies in these deposits be made.

Possible sources and transport pathways of loess deposited in Poland and Ukraine from detrital zircon U-Pb age spectra

Abstract A provenance study was carried out on loess deposits of SE Poland and Ukraine. For this purpose, loess samples were taken from 18 loess outcrops, and the U-Pb ages of detrital zircons were determined using a SHRIMP IIe ion microprobe. Additionally, studies of the anisotropy of magnetic susceptibility were conducted in the selected sections in order to reconstruct palaeowind directions. Zircons from the youngest loess in SE Poland and western Ukraine yield predominantly Cadomian and younger ages. On the other hand, the pre-Cadomian zircons are the most frequent in the loess from the Dnipro Basin in central and northern Ukraine. While the number of zircon grains analysed does not allow a detailed assessment, the location of the boundary between these two provinces of zircon provenance indicates that the catchment areas of major rivers provided most of the aeolian material. This boundary delimits areas of mountain provenance-river and continental glacier provenance-river transport modes of loess origin. The loess patches located close to the large river valleys were supplied with aeolian material that was blown mainly from the neighbouring riverbeds, as it was inferred from the palaeowind directions. Similar age spectra characteristics for the fine- and coarse-grained zircons demonstrate a significant role for the local transport of detrital material. The same age spectra observed in the loess of different age can indicate a substantial redeposition of sediment.

Prediction of Muddy Floods Using High-Resolution Radar Precipitation Forecasts and Physically-Based Erosion Modeling in Agricultural Landscapes

The monitoring, modeling, and prediction of storm events and accompanying heavy rain is crucial for intensively used agricultural landscapes and its settlements and transport infrastructure. In Saxony, Germany, repeated and numerous storm events triggered muddy floods from arable fields in May 2016. They caused severe devastation to settlements and transport infrastructure. This interdisciplinary approach investigates three muddy floods, which developed on silty soils of loess origin tending to soil surface sealing. To achieve this, the study focuses on the test of a historical forecast modeling of three muddy floods in ungauged agricultural landscapes. Therefore, this approach firstly illustrates the reconstruction of the muddy floods, which was performed by high-resolution radar precipitation data, physically-based erosion modeling, and the qualitative validation by unmanned aerial vehicle-based orthophotos. Subsequently, historical radar precipitation forecasts served as input data for the physically-based erosion model to test the forecast modeling retrospectively. The model results indicate a possible warning for two of the three muddy floods. This method of a historical forecast modeling of muddy floods seems particularly promising. Naturally, the data series of three muddy floods should be extended to more reliable data and statistical statements. Finally, this approach assesses the feasibility of a real-time muddy flood early warning system in ungauged agricultural landscapes by high-resolution radar precipitation forecasts and physically-based erosion modeling.

Ferdinand von Richthofen’s loess research in China

Ferdinand von Richthofen (1833–1905), a great German geographer and geologist, was well known for his loess research in China. Here we reexamine the background of Richthofen’s loess research and review his contributions and limitations according to the existing literature. An important historical background of Richthofen’s loess research was that foreigners have been authorized to travel in the interior of China since the 1860s as a result of the Treaties of Tientsin. Richthofen made seven comprehensive scientific explorations in China in 1868–1872, whereas loess research was just one of his topics. He experienced dust weather on the Loess Plateau, where he had direct and deep impressions of the transport of dust, which should have helped him develop the hypothesis of the Aeolian origin of loess. Apart from the Aeolian hypothesis, his other achievements include the differentiation of the regenerated loess from the original loess, the discovery of the loess near Nanjing, the identification of the desiccated lakes as sources of dust storms, and the identification of “vertical cleavage” as a major property of loess.

Origin and evolution of modern loess science – 1824 to 1964

Loess is the most important aeolian deposit of the Quaternary and plays an important role in explorations of the evolution of paleoclimate and paleoenvironment. In recent years, historians of science have been working on how loess research originated, developed, and was promoted in Europe in the early 19th century. The Chinese community has a clear history of the loess research from the late 20th century. However, it remains unclear when and how modern loess studies were communicated between western and eastern academic societies and who contributed to the development and dissemination of modern loess knowledge, especially from the western to the eastern societies. Based on books, essays, memoirs, travel notes, published letters, and other types of records from geologists, such as K. Leonhard (1779–1862), C. Lyell (1797–1875), and R. Pumpelly (1837–1923), the present study clarifies the way and process by which loess research originated from the Rhine valley and spread to Britain onto the United States and, in particular, China. It was discovered that loess was formally defined in 1824 in the Rhine valley. In the 1830s, L. Horner (1785–1864) and Lyell introduced loess research from the Rhine valley to Britain. At the same time, Lyell put forward the theory of the fluvial origin of loess and verified his theory by expanding study areas to the United States. In 1866, Pumpelly, the first foreign geologist investigating Chinese loess, put forward lacustrine formation of loess. Pumpelly’s hypothesis was soon argued against in 1870 by F. von Richthofen (1833–1905), who thought loess was formed via an aeolian mode based on a wide investigation in the Loess Plateau of China. Although the above main hypotheses originated based on investigations of Chinese loess, they were not disseminated to China and received by Chinese scholars in a timely manner, and the local loess research in China launched almost 130 years later by the stimulation from work by scholars of the Soviet Union.

The rock-forming role of biota

Stromatolites and other microbiolites formed in early epochs as a result of the life activity of primitive communities of microorganisms. It has become possible to prove that communities of higher organisms can form more powerful layers of sedimentary rocks. Back at the beginning of the 20th century, some geologists and soil scientists proposed a soil-related theory of the origin of loess and other sedimentary rocks, but this idea did not gain recognition. Functional ecology describes the metabolism of ecosystems with the utilization of waste in the form of sediments, which geologists jointly with ecologists can verify in model experiment. Then it will be possible to read freely the calendar of nature coded in stratigraphic columns of geological cross sections.

Sárga föld, lősz, lösz: Short historical overview of loess research and lithostratigraphy in Hungary

The over 150 years of Hungarian loess research can be divided into three main phases. (1) The first phase is the early times of the Hungarian loess research from the 1850s until the beginning of the 20th century. This was the time of recognition, definition of loess, and the birth of the first ideas about the origin of loess, following the international scientific trends. However, independent ideas were developed in Hungary, inspired by the main trends. One of the most complex ideas was Koch's ‘loess-sea’-idea, which describes the origin and deposition of the material of loess from the denudation processes to glaciers, fluvial transport, and the accumulation of the fine grained material in a giant freshwater lake located in the middle of the Carpathian Basin.(2) The second phase, the golden age of loess research, is separated into two periods. The first period was the investigation and classification of the material of loess (e.g. studies of source area of loess) finishing with the definition of the paleosols, and their connection to the polyglacial interpretation of the ice age (from the start of the 20th century until the 1930s). The first and detailed lithostratigraphical subdivision of Hungarian loess was in the spotlight of the second period of the second phase. The aim of the studies was the correlation of the layers of some key sections, and the glacial and interglacial phase of the Pleistocene (e.g. correlation of different proxies with the ‘astrocyclostratigraphical’ Milanković curve, or later with the oxygen isotope curves).(3) Nowadays, some studies try to advance a deeper understanding the complex mechanism working in the glacial (stadial), interglacial (interstadial), or transition periods of the Pleistocene. Recent studies are part of the beginning of the third phase.

Loess origin, transport, and deposition over the past 10,000years, Wrangell-St. Elias National Park, Alaska

Abstract Contemporary glaciogenic dust has not received much attention, because most research has been on glaciogenic dust of the last glacial period or non-glaciogenic dust of the present interglacial period. Nevertheless, dust from modern glaciogenic sources may be important for Fe inputs to primary producers in the ocean. Adjacent to the subarctic Pacific Ocean, we studied a loess section near Chitina, Alaska along the Copper River in Wrangell-St. Elias National Park, where dust has been accumulating over the past ∼10,000 years. Mass accumulation rates for the fine-grained (

Tracing the origin of loess in Hungary with the help of heavy mineral composition data

Heavy mineral composition of the fine sand fraction in the Hungarian loess sediments provides important data about the closer sources of the loess in the Carpathian Basin. Quantitative detrital heavy mineral compositions of 216 loess, loess-like sediment, and paleosol samples were compared to each other, and to recent fluvial sands and different Cenozoic sands and sandstones of Hungary using statistical methods: cluster analysis, principal component analysis and discriminant analysis.Usually, garnet is the most frequent detrital heavy mineral in the studied loess sections, followed by chlorite, magnetite, epidote, and amphiboles. Old Loess and Young Loess have similar compositions, indicating uniform or similar sources. Based on the similarities, the garnet-rich loess sediments could originate from aeolian reworking of the floodplain sediments of the Danube and other rivers of Transdanubia, and the local Cenozoic sands of the uplifting Transdanubian Central Range and Transdanubian Hilly Region. The biotite- and tourmaline-rich loess in South Transdanubia, and the loess with high pyroxene content in the North Hungarian Range, had some material from nearby sources: weathered granitoids and volcanic rocks, respectively, or sediments of local rivers, which carried detritus of these rocks. The new results presented in this paper confirm numerous earlier ideas about the origin of loess in the Carpathian Basin, but also suggest newly identified sources of the loess particles at several locations.

The influence of the plantation establishment method on the yield of marshmallow (Althaea officinalis L.) flowers

The field experiment with one- and two-year-old marshmallow plants was carried out in Zamość on brown soil of loess origin in 2002-2004. There were four methods of plantation establishment: 1) direct sowing in the field (control object); 2) direct sowing in the field with cover of polypropylene sheet; 3) by seedlings from a plastic house; 4) by seedlings produced in multi-cell propagation trays. It was found that, in the case of one-year-old plants, all the methods of plantation establishment significantly increased the yield and the number of marshmallow flowers, as compared to the control object, but the best results were obtained when the plants were propagated from seedlings produced in multi-cell trays. Taking into account the two-year-old plants, no significant impact of the plantation establishment method on flower yield was found. On average, total yields of flowers varied from 17.2 dt×ha<sup>-1</sup> in the first year of vegetation to 27.8 dt×ha<sup>-1</sup> in the case of the two-year-old plants.

PARTICLE SIZES, MAGNETIC PROPERTIES AND ORIGINS OF LOESS DEPOSITS FROM HUANGNISHAN HILL IN NANTONG, JIANGSU PROVINCE

Huangnishan hill is located in the southern area of Nantong City,Jiangsu Province. In this paper,we studied magnetic and granulometric characteristics of loess deposits from the Huangnishan hill and the origin of loess. The sediments are dominated by silty clay,and finer than those of both the Xiashu loess in Zhenjiang and the loess in the Chinese Loess Plateau. Huangnishan loess is similar to Xiashu loess in magnetic property,implying that the Huangnishan loess is the same as the Xiashu loess in Zhenjiang area,which is of aeolian origin. The fluctuation of magnetic parameters indicates that paleoenvironmental changes were recorded in the loess,too. The lower content of fine-grained ferrimagnetic minerals and higher S-100 values of the deposits in comparison to the Xiashu loess suggest that the Huangnishan loess experienced a lower degree of pedogenic alteration than that of the Xiashu loess in Zhenjiang.

Evidence for the Aeolian Origin of Loess in the Danubian Plain

The present work considers the evidences for the Aeolian origin of loess in the Danubian plain, put forward by previous authors, which have been amended with results from new investigations. One of the main proofs consists in the grain-size composition changes of the loess complex from north to south, from east to west and with depth. Other evidences are the well expressed directions of loess winnowing in the Danubian plain: from west-northwest and north-northeast. The next evidence for the Aeolian origin of loess is the sequence in the loess accumulation process. It was started before 2.59 Ma BP along the coast of the Dacian basin and after its regression loess winnowing was also spread on the occupied by the basin territories (0.82 Ma BP). The loess complex becomes younger towards the Danubian terraces. The deflation of the loess fine earth material occurred from the flooded areas of the Paleodanube River and its tributaries, from the Black sea shelf and the clayey alluvium of the Dacian basin. The orientation of the deflation area with respect to the transporting Aeolian corridor was one of the reasons for the differences in the lithostratigraphy and the thickness of the loess complex. Five loess regions were differentiated in the Danubian plain: Northeast, “Yantra-Vit”, “Vit-Ogosta”, “Ogosta-Lom” and the Black Sea region.

Origin of Loess in the South West of Saudi Arabia

Origin of Loess in the South West of Saudi Arabia

On the relationship between environmental aridization of the Loess Plateau and soil water in loess

The similarity between loess palaeo- environment and geographic distribution of modem bioclimatic zones is taken as a starting point; the relationship between the environmental aridization and soil water in loess ia discussed from the point view of the soil water energy status and their soil water physical characteristics of modem lcessial soils on the Loess Plateau. The soil water content becomes less and less from southeast to northwest, which not only provides favorable conditions for dust production by wind of loess origin, but also reveals that there is obviously a directional change in the environmental drought intensity of the Loess Plateau.

Loess studies in central United States: evolution of concepts

Few words in the realm of earth science have caused more debate than “loess”. It is a common term that was first used as a name of a silt deposit before it was defined in a scientific sense. Because this “loose” deposit is easily distinguished from other more coherent deposits, it was recognized as a matter of practical concern and later became the object of much scientific scrutiny. Loess was first recognized along the Rhine Valley in Germany in the 1830s and was first noted in the United States in 1846 along the lower Mississippi River where it later became the center of attention. The use of the name eventually spread around the world, but its use has not been consistently applied. Over the years some interpretations and stratigraphy correlations have been validated, but others have been hotly contested on conceptual grounds and semantic issues. The concept of loess evolved into a complex issue as loess and loess-like deposits were discovered in different parts of the US. The evolution of concepts in the central US developed in four indefinite stages: the eras of (1) discovery and development of hypotheses, (2) conditional acceptance of the eolian origin of loess, (3) “bandwagon” popularity of loess research, and (4) analytical inquiry on the nature of loess. Toward the end of the first era around 1900, the popular opinion on the meaning of the term loess shifted from a lithological sense of loose silt to a lithogenetic sense of eolian silt. However, the dual use of the term fostered a lingering skepticism during the second era that ended in 1944 with an explosion of interest that lasted for more than a decade. In 1944, R.J. Russell proposed and H.N. Fisk defended a new non-eolian, property-based, concept of loess. The eolian advocates reacted with surprise and enthusiasm. Each side used constrained arguments to show their view of the problem, but did not examine the fundamental problem, which was not in the proofs of their hypothesis, but in the definition of the term. Between 1944 and about 1950, the debates about loess reached a maximum level of complexity. The main semantic problem was submersed in peripheral arguments about physical properties and genetic interpretations. The scholarly treatment of the subject by Fisk and Russell stimulated quality responses from a diversity of earth scientists interested in academic and applied studies, particularly geo-history, pedology, soil mechanics and stratigraphy. The long-lasting popularity of loess studies during the bandwagon era lasted to about 1970. By that time, the analytical and technical interests had attracted the mainstream into the fourth era with a focus beyond the old arguments. Although Fisk and Russell found themselves defending an unpopular theory, they stimulated a scientific interest in the late Quaternary history of the Mississippi Valley that may never be exceeded.

Granulometric investigations of loess profiles in Hungary

The granulometric analysis of loess varieties is meant to contribute to the subdivision of loess sequences, to the reconstruction of the environments of loess formation (identifying areas of loess origin [from where the dust derives], “geographical obstacles” to transport, contemporary wind directions [through drawing isokatharoses lines connecting points with identical FG values] and even wind velocities) and subsequent changes in climatic and geographical conditions. It was investigated whether loesses and loess-like deposits can be described by a generalised grain size parameter (fineness grade, FG) or to what extent other granulometric indices can lead to a more differentiated picture of grain size variation. Fineness grade was used to denominate sediments and to identify finer and coarser sections in the series;K d index indicates the lithostratigraphical positions of cold stages (maximum values) and warm stages (minimum values); finesorting (S o) points to eolian accumulation, while fluvial deposits (bedload, saltated and suspended load) are poorly sorted;kurtosis (K) allows conclusions for the reworking of the deposit andasymmetry (Sk) indicates the factor active in the accumulation of the deposit. The paper concentrates primarily on the study of variation in the vertical profile of deposits. Along with other indices, fineness grade was found useful in distinguishing between loess varieties and other sediments and could even replace the function of the conventional index median value (Md).

Basic Geologic Problems of Loess in China

Abstract The geology of loess in China involves many problems. This paper deals only with the basic ones of the origin of loess, the geologic setting and palaeoenvironmental evolution leading to the formation of the Loess Plateau, and the regional stratigraphy of loess deposits, particularly the last problem. A better knowledge of the formation and development of the loess deposits in China has been obtained through analysis and correlation of lithostratigraphy, biostratigraphy, magnetostratigraphy, climatostratigraphy and chronostratigraphy.

Formation of quartz silt during humid tropical weathering of dune sands

Quartz dune-sand grains in northeast Australia break down in situ under humid tropical weathering conditions to form substantial amounts of silt. Fragmentation appears to occur primarily due to silica solution along microfractures and dislocation structures in grains which have experienced tectonic deformation prior to deposition. The surface textures of quartz grains viewed with the SEM exhibit a close dependency on crystallographic properties. In the B and C horizons of some weathered late Pleistocene dunes silt forms up to 10% of the bulk sediment. Local remobilisation of such deposits by wind allows selective removal of the silt which is later deposited as a thin surficial sheet in more sheltered areas downwind. These observations provide further evidence that weathering processes provide a major mechanism of silt formation and are an important factor to be considered in relation to the origin of loess and siltstones.