Loess Formation Research Articles

Characteristics of the typical loess profile with a macroscopic tephra layer in the northeast China and the paleoclimatic significance

Tephra layers can serve as ideal datable horizons to provide invaluable datums for supplementing research on loess-paleosol sequences. The objective of this research was to evaluate a typical loess profile interbedded with a macroscopic tephra in northeastern China to better understand its formation to determine the potential impact of volcanism on climate change, as evidenced by loess pedogenesis. Geochemical and physical properties of the profile were determined and compared with loess materials from other areas to address its characteristics and potential significance for understanding climate variability. Results showed the tephra layers with overlying loess horizons were uniform in parent material, as inferred from evidence such as uniform Ti/Zr ratios with depth, similar rare earth element distribution patterns, and major elemental distributions with depth. The volcanic properties in the bottom of the profile, including morphology, high phosphate adsorption capacity (PAC) and pH (NaF) values, further supported the speculation that the depositions of aeolian dust and volcanic materials were synchronous with pedogenic processes. According to the comparison of magnetic susceptibility of the typical profile with the global δ18O curve, the local paleoclimate showed an increase in temperature in warmth and wetness, which may have been affected by volcanism. Research on the loess profile interbedded with a macroscopic tephra could improve our knowledge of loess formation and deepen our understanding of the impact of volcanism on climate changes.

Abrupt last glacial dust fall over southeast England associated with dynamics of the British-Irish ice sheet

Loess deposits in southern Britain contain a record of dust, climate and landscape dynamics over the last glacial, yet their age and accumulation rate remain poorly known. Furthermore, the environmental controls on the loess-soil stratigraphy shown in the thickest deposits in southeast England are still debated. Here we apply the first high sampling resolution quartz optically stimulated luminescence study of dust accumulation and loess formation in Britain at the Pegwell Bay site in east Kent. We couple this to mineral magnetic, particle size and geochemical analyses to understand climate, environment and post depositional modification of the loess. The luminescence ages and Bayesian age modelling results suggest two phases of greatly enhanced dust accumulation at the site. Loess began to accumulate around c. 25–23.5 ka, coinciding with Heinrich event 2, and after subsequent lower accumulation rates, a second enhanced phase of deposition occurred at around 20–19 ka. We propose a model where the dynamics of the British-Irish and Fennoscandian Ice Sheets, associated glacial lake drainage, and linked reorganisations of atmospheric circulation, all controlled loess accumulation in southern Britain. Accumulation in the first phase was triggered by increased sediment supply from initial retreat of the North Sea ice lobe, and drainage of Dogger Lake. Loess accumulation during this phase was enhanced by easterly winds from Atlantic depressions tracking to the south of Britain, caused by the maximum extent of the Irish Sea Ice Stream at c. 25–24 ka. The subsequent retreat of the western part of the British Irish Ice Sheet then allowed storm tracking further north, which reduced effectiveness of dust transporting winds across southern Britain, while sediment supply and availability was reduced in North Sea source areas. A second retreat of the maximum extent of the North Sea Lobe of ice after c. 21–20 ka would have led to another abrupt input of sediment-rich ice dammed lake and meltwater from eastern England and the North Sea into the exposed southern North Sea area. This would have again dramatically increased sediment availability for transport and deposition as loess in SE England, resulting in the second dust accumulation phase. We also propose that the abrupt stratigraphic change from calcareous to non-calcareous loess up section at Pegwell Bay was driven, not by these changes in dust input, but rather deepening of the permafrost active layer after c. 21 ka. This deepening was associated with warmer and wetter conditions driven by Atlantic storms tracking further north following the regression of the Irish Sea Ice Stream and overall ice sheet retreat. As such, last glacial dust dynamics and loess accumulation in Britain is highly influenced by the interaction of the British Irish Ice Sheet the Fennoscandian Ice sheet, Atlantic storm tracks, and the topography and drainage of the exposed North Sea.

Variation in dustfall on the western Chinese Loess Plateau

Dustfall samples from the western Chinese Loess Plateau (CLP) were collected from 2013 to 2016 at Jiuzhoutai for dustfall variation analysis. Results showed that the seasonal dustfall variations were non-significant in the region, indicating dustfall sources with inconsistent patterns largely contributed to the modern loess formation. The average rate of loess accumulation was approximately 0.34 mm/year, which is much higher compared to the other periods of the Holocene. In addition, the lack of regular patterns of dustfall contents in the coarse fraction (> 50 μm in diameter) indicates a proximal source with crustal origins, which is a dominant source for the modern loess. From 2013 to 2016, the dustfall from crustal origins increased by approximately 19%, and among those collected dustfall, approximately 24% came from pollutants, indicating that anthropogenic activities such as industrial pollutants and vehicle emissions played an important role in modern loess accumulation.

Loess-derived polygenetic soils of North-Western Italy: A deep characterization of particle size, shape and color to draw insights about the past

The multiplicity of units present in a single loess bed greatly complicates the reconstruction of the history of polycyclic loess-derived soils. The present study implemented a combination of techniques to characterize different depositional events in a pedogenized loess formation of North-Western Italy. Field morphological observations, laboratory Particle Size Distribution (PSD) analyses, and single-grain image processing techniques were applied.Five different loess depositions, or cycles, were distinguished in the field. Laser PSD curves highlighted the fine nature of the studied loess, which stood out even in comparison to similar Italian loess-derived soils. All PSD functions showed a tri/bimodal distribution with a dominant peak at 8–14 μm, wider in younger depositions. The second most relevant peak, at 0.5–4 μm, displayed a greater intensity in older cycles where it also fell in correspondence of slightly bigger particles. The fine-grained nature of the loess was read as a sign of its alluvial origin, therefore the Po plain has been addressed as the source of the material. This hypothesis was supported by evidence of a dominant SE-to-NW paleo-wind direction, proved by the spatial trends of the coarse and fine silt fractions. The typical aeolian size-dependant depositional trait of one of the cycles (IV) was however opposite to that of the other four loess depositions. Therefore, the source of this material was attributed to a site North of the study area where, right behind the Lanzo ultramafic massif, an ice lobe stretched during the Last Glacial Maximum (LGM). Image analysis supported this hypothesis: as the loess grains of cycle IV were significantly darker colored than the others, this would agree with the provenance from an ultramafic source. In conclusion, the variety of applied techniques allowed us to combine different pieces of information in order to assess the physical and morphological properties of the studied loess-derived soils, trying to determine the most probable sources of the material and the weathering pathways.

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.

Assessment of deforestation impact on soil erosion in loess formation using 137Cs method (case study: Golestan Province, Iran)

Golestan, a province in the North-East of Iran, is characterized by high coverage of loess deposits. Since 1963, the area has experienced approximately 200,000 ha deforestation due to land-use changes in agriculture and increasing demand for wood. Approximately, 110,000 ha of the clear-cut lands are under dry-farming, mainly for wheat cropping, and about 86,000 ha have been reforested. This IAEA funded project is the first attempt to use nuclear techniques in the East of Hircanian Forest for determination of on-site impacts of deforestation due to two land-use changes (i.e. dry farming and reforestation). Practicing long-term dry-farming led to 60% soil losses with a mean rate of 2 mm per year. The net erosion rate of croplands on loess deposits in the study area was 32.27 t ha−1 yr−1. Reforestation, cultivation of even-aged Cypress trees since 1993, showed 13 to 60 percent effectiveness in soil conservation. Dry-farming land use resulted in the loss of 95 t ha−1 soil organic carbon (SOC) stock at a mean rate of 1.7 t ha−1 over 54 years. Cultivating Cypress trees successfully restored the SOC content by 100% compared with the SOC in original forests. The conversion of dry-farming lands to orchards of olive trees since 2004, brought more income for farmers but were less effective in soil conservation because of low canopy cover of olive trees. Our data provide key information and guidance for land users and decision-makers about implementing strategic and sustainable conservation practices to restore degraded land.

On the formation of desert loess

AbstractSequences of quartz-rich coarse (20−63 μm) silt occur in many low- and midlatitude unglaciated arid and semiarid areas and have been termed “desert loess.” The processes by which these deposits are generated have been debated for decades. All hypotheses to explain their origin seek to provide mechanisms for the generation of silt-sized material without glacial grinding, which is the main process involved in the production of coarse silt at high latitudes. Possible mechanisms for the formation of coarse silt in arid regions include derivation from preexisting siltstones, mechanical weathering of silicate rocks, and abrasion of sand grains in active dune environments during intense transport events. Examination of the characteristics of desert loess and field and laboratory experiments to assess the role of dune areas as a source of coarse silt by abrasion and/or resuspension of residual fines suggests that many loess sequences are dominated by locally derived coarse silt. Improvements in the characterization of desert loess particle size, mineralogy, and geochemistry are needed, however, to identify sources and sinks of coarse silt, especially when combined with climatic back-trajectory analysis. Properly scaled experiments and modeling of particle collisions will also help to better quantify the effectiveness of abrasion in the generation of coarse silt in support of field observations.

Late Quaternary loess accumulation at the Rudak section in Uzbekistan, central Asia: Chronology and palaeoclimate implications

Many studies have been carried out to understand the nature of the loess formation and its palaeoenvironmental significance in different parts of Eurasia, especially Europe and China. However, in spite of its key position, our knowledge about the loess deposits at the core of the Eurasian loess belt in central Asia is still limited, particularly in terms of absolute dating. This study presents a new luminescence chronology of a loess-palaeosol sequence (Rudak section) in the vicinity of the Gissar Range, Uzbekistan, using both quartz optically stimulated luminescence dating and polymineral post-IR IRSL dating techniques. The dating results suggested a loess accumulation history over the past 180 kyr at Rudak section, characterized by a great depositional hiatus during the entire last glacial period, likely owing to too harsh climate conditions for favouring dust accretion and loess preservation in the piedmont areas of central Asia. Hence, contrasting with the traditional concept of continuous (quasi-continuous) deposition of loess, the direct stratigraphical correlation might be problematic for climatic interpretation of loess-palaeosol sequence in this area. Furthermore, magnetic susceptibility of Rudak section demonstrated the moisture peaks in phase with ice-volume minima over the glacial and interglacial cycles, indicating moisture variation in the Westerlies-dominated central Asia was broadly consistent with that in monsoonal Asia on orbital timescales, but nearly contrasting picture with each other on the suborbital timescales, at least through the Holocene epoch. The Westerlies-dominated central Asia has generally experienced a dry first half and a wet second half of the Holocene, which has likely been driven by solar insolation gradients between mid-latitudes and high-latitudes as well as the melt-water flux.

Effect of depositional water content on the collapsibility of a reconstituted loess

Loess, a wind-blown silty soil, can be deposited under a variety of moisture conditions, including dry deposition, wet deposition and gravitational settling of aggregations formed in moist air by capillary forces at grain contacts. This experimental study uses single and double oedometer tests to assess the effect of depositional water content on the collapse potential of reconstituted samples of the Langley Silt Member, known as Brickearth, a natural loessic soil. A freefall sample preparation technique was used to mimic loess formation and environmental scanning electron microscopy was used to relate the observed behaviour to sample fabric. The results show that loess deposited at higher water contents has a greater collapse potential, which is shown to be related to its looser, more granular fabric.

On Staging in the Loess Formation of Siberia

On Staging in the Loess Formation of Siberia

Shear Band Formation and Strength of Loess in True Triaxial Tests

Abstract This study presents experimental results from a strength test of loess from China’s Xi’an Bailu plateau. The measurements were made with a true triaxial apparatus. Some explored characteristics were shear stress ratio, intermediate principal strain and volumetric strain changing with major principal strain, and strength criteria on the meridian and octahedral planes. The failure strength and the strain and shear band models of loess specimens were analyzed. The results clearly show shear bands in the loess specimens under true triaxial principal stresses. Softening of intact loess occurred under low confining pressure and small intermediate principal stress b-values. Hardening occurred under greater confining pressure and intermediate principal stress parameters. Structural soil mass adjacent to the shear band demonstrated a relative sliding movement and development of a shear band. The strength line on the meridian plane was linear, and the strength curve on the octahedral plane was a curved-edge-triangle shape consistent with Lade’s strength criterion. The complex pattern of the shear-band–induced failure mode is attributable to the structural characteristic of natural loess and the loading conditions.

Atmospheric dust dynamics in southern Central Asia: Implications for buildup of Tajikistan loess sediments

Loess, as a terrestrial aeolian deposit, forms extensive landforms over several parts of the Central Asia, especially in southern Tajikistan. However, the dust dynamics for the loess formation over this region remain largely unknown. This study uses loess trace elements and meteorological reanalysis data to study the linkages between the atmospheric circulation patterns, aeolian dust transport and deposition and formation of loess sediments with emphasis in southern Tajikistan. Meteorological data indicates that the dust emissions and accumulation over southern Tajikistan maximize during the hot and dry summer season. The foothills in the north Afghanistan are the most likely dust sources, while the Central Asian deserts (e.g. Karakum) may also have a minor contribution. The prevailed near-surface air currents in the southern Central Asia run southward and then eastward when meeting the Hindu Kush Mountains. The dust-plume transport is mostly blocked by the towering Pamirs, and the deposits settle down forming thick and extensive loess sediments. Long-term trends in precipitation, wind speed and surface moisture affect the dust emissions, while there is a strong evidence of linkage between changes in the intensity of the Caspian Sea - Hindu Kush Index (CasHKI) and dust activity in the Afghan-Tajik Basin. It is recommended that the CasHKI modes can determine the dust activity, while precipitation affects most likely the interannual timescales, which have implications for interpretation of palaeoclimatic proxies of loess-paleosol sequences. However, further challenges come from the proper use of CasHKI in paleoclimatology and comprehensive research is needed.

Effects of carbonate on the structure and properties of loess and the corresponding mechanism: an experimental study of the Malan loess, Xi’an area, China

The structural, physical and morphological characteristics of loess will change as a result of the dissolution of mineral components, mainly carbonate, when it is exposed to acid rain, industrial acid leakage or other acidic environments. This study investigates the physical and structural characteristics of the Malan loess, Xi’an area, China, after carbonate dissolution. The presence of carbonate is determined by scanning electron microscopy (SEM)/energy-dispersive X-ray (EDX) and X-ray diffraction (XRD) analysis. The loess was soaked with 0.2 mol/L acetic acid. The degree of degradation of the loess, carbonate and other minerals was determined by the abundances of elements in the solution. Microstructural analysis combined with the loess characteristics of adsorption, water stability, compressive yield stress and shear strength are used to explain the changes in the soil structure after carbonate dissolution. The results show that bonds in the cementation are irreversibly lost during the remoulding process, and additional bonds are destroyed with the removal of large amounts of carbonate, causing the skeletal particle surface area, specific surface area, adsorption capacity and water stability to decrease. The compressive yield stress and cohesion of the soil are considerably more sensitive at higher water contents. Calcium carbonate is the main carbonate component in the loess, and the secondary calcium carbonate connects the skeletal particles by coating and bridging; the strong cementation stops the particles from dispersing in water. The change in strength and deformation of the soil change its microstructure, which indicates that the secondary calcium carbonate affects the soil structure and stability by reducing the aggregate wettability and changing the mechanical strength of the soil aggregate. This paper will contribute to elucidating the formation and destruction of loess.

Distribution of Trace Elements in Holocene Loess-paleosol Sequence and Environmental Change in Lower Reaches of The Yellow River

Based on field investigation, samples in loess-paleosol sequence profile were collected systematically at Longshan site in Shangdong province in lower reaches of The Yellow River. Trace elements(Mn, Cu, Ba, Ni, Pb, Rb, Sr, Ti, V and Zn) were measured and analyzed systematically by X-Ray and compared with climate substitution index(grain size, Rb/Sr, Ba/Sr). The results as follows:(1) According to the significant correlation between the content of Ti, Ba, Cu, Ni, V, Zn, Rb, Pb, Sr in the LS loess-soil sequence and the index of soil strength (soil grain size, Rb/Sr, Ba/Sr), it can be concluded that the migration and change of trace elements in Holocene period were mainly affected by the environmental evolution of this period. Mn is insensitive to climate change in this profile. The content of Pb in the surface layer of soil is the highest, which may be caused by human activities. (2) The contents of Ti, Ba, Cu, Ni, V, Zn and Rb in the paleosol( S0 ) were accumulated accompanied by the clay(< 5μm) increase while the coarse silt(10∼50μm) reduced, suggesting the intensified pedogenic modification to the accumulated dust when it was humid climate. It implied that the climate was warm and humid during the mid-Holocene optimum. (3) Content of Ti, Ba, Cu, Ni, V, Zn, Rb and clay(< 5μm)in loess layer (Lt, L1, L0) was lower and coarse silt (10-50μm) content was higher when compared with the paleosol layer (S0), suggesting that the intensity of soil formation was weak and aeolian sand activity was frequent. It further indicated that the paleoenvironment was cold and dry with frequent dust storms during the periods of loess formation.

Origins and genesis of loess deposits in central Spain, as indicated by heavy mineral compositions and grain‐size variability

AbstractThe formation of loess deposits strongly depends on the availability of deflatable dust‐sized material. Identification of source areas and mechanisms of dust production is essential for an appropriate characterization of related palaeoenvironmental conditions. So far, little research has been done on loess deposits in the Mediterranean region and information about mechanisms of dust production is very rare. In this context, it is not clear from where the loess deposits from the upper Tagus Basin in central Spain originated. The main objective of this study was to find out whether these loess deposits were formed primarily by mountain processes and fluvial comminution, or whether they have their origin in the weathering of Tertiary marls in the centre of the Madrid Basin. A further concern was to link the determined source areas with loess formation mechanisms and concomitant environmental contexts. Following a comprehensive approach using heavy minerals and grain‐size data, together with information on stratigraphic features and geomorphic positions, different local loess sources could be identified. This study shows that during the last 35 kyr a major proportion of the Tagus loess deposits was deflated from river floodplains, while the mountain region of the Iberian Range was identified as a significant source of respective floodplain sediments. Based on heavy mineral compositions and dating results, it was found that during Heinrich Stadial 3, sediment supply from the Iberian Range strongly increased, suggesting an environmental shift from initially warmer towards colder temperatures in late Marine Isotope Stage 3. Furthermore, it was found that grain‐size patterns clearly indicate maximum wind strengths during Heinrich Stadial 3, followed by Heinrich Stadial 2 and Heinrich Stadial 1. These results demonstrate that the formation of dust‐sized particles in this part of the Mediterranean operated similar to many other places in temperate and continental regions, and that weathering processes linked to hot and dry environments were only of minor importance.

Feasibility of applying viscous remanent magnetization (VRM) orientation in the study of palaeowind direction by loess magnetic fabric

AbstractThe loess formation sampling method on the Chinese Loess Plateau generally involves the acquisition of samples from the basset section and the drilling core. Constraints imposed by the precision of the drilling machine operation make it difficult to determine the orientation of the samples due to the rotation of the core.Although researchers have proposed solutions for reconstructing the north direction of the samples by adopting the viscous remanent magnetization (VRM) orientation, it remains uncertain whether this approach can be adopted in studies that use the magnetic fabric to trace the palaeomonsoonal direction, and the degree to which this approach will change the magnetic fabric results.Based on the achievements of other researchers, we adopted the VRM orientation of the basset section samples oriented in the field. By determining how the VRM orientation changes the magnetic fabric of loess over different demagnetization temperature ranges, we can draw the preliminary conclusion that there is no significant difference between the magnetic fabric information of the loess obtained at 100–150°C VRM orientation and that obtained from the field orientation (the statistical bin size is 22.5°, significance level α = 0.05). This indicates that the VRM orientation approach is feasible for studying non-oriented drilling core samples to determine the prevailing surface paleowind direction with appropriate precision.

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.

New evidence for the provenance and formation of loess deposits in the Ili River Basin, Arid Central Asia

Abstract Loess deposits are thick and widespread along the piedmonts of Arid Central Asia (ACA), however the source (provenance) and processes of formation of these fine-grained aeolian deposits are poorly understood. Here we investigate the provenance and possible distribution mechanisms for loess along the slopes of the Ili River basin, located in northwest China and southeastern Kazakhstan, using a grain-size mixture model and an elemental geochemistry-based source fingerprinting technique. Our results indicate that the Ili loess experiences low rates of sedimentary recycling downstream within the basin piedmont, and are strongly dependent on local geomorphic context. Loess deposits are dominated by proximal sources, indicating short-distance aeolian transport from the Ili River alluvial plains and local proluvial fans. Local sourcing dominated regardless of location within the catchment, although the proportion of fluvial input increases proportionally with increasing distance downstream. Our results suggest that the Central Asian deserts did not act as significant interim storage reservoirs for the loess deposits in the Ili River basin, which contrasts with the popular model for piedmont loess formation across Central Asia. Most likely the relatively enclosed and highly variable basin topography precluded transport from the open desert steppe into the upper Ili River valley. Our study provides the first clear evidence for a genetic link between the Asian high mountains and the loess of the adjacent piedmonts, based on geochemical and grain-size data, with the caveat that the high degree of topographic variability along the Tianshan piedmont likely results in a strongly localized influence on loess formation and accumulation.

The first loess map and related topics: contributions by twenty significant women loess scholars

AbstractWomen scholars have contributed to the study of loess. Charlotte Hibbert made the first map of loess distribution and there were many subsequent achievements. The twenty people selected represent a subjective choice; there is no overall biobibliographical metric that can be applied. The twenty are mss: Hibbert, Owen, Swineford, Conea, Marković-Marjanović, Fotakieva, Ivanova, Davin, Coude-Gaussen, Wintle, Matviishina, Gerasimenko, Billard, Grabowska-Olszewska, Sycheva, Mavlyanova, Rendell,Łanczont, Klukanova, Morozova. The INQUA Loess Commission provides a convenient temporal divide, and also a divide in style of loess investigation: early studies pre-Commission; Loess Commission activities; modern scientific loess research post-Commission (after 2003).TopicsHypotheses of loess formation, aeolian vs. fluvial, aeolian vs. in-situ, desert loess, Danubian loess, INQUA Loess Commission, Dating techniques, hydroconsolidation, loessification, Ukraine, Russia, Central Asia, loess structure.The paper by Jelena Marković-Marjanović in the 1961 INQUA Loess Symposium was one of the key pioneering documents in the development of loess stratigraphy; it should be more widely recognized.

The formation of loess ground by the process of loessification: a history of the concept

Abstract Loessification is a process by which a body of non-loess ground is transformed into a body of loess ground. The history of loessification is one of controversy and confrontation, largely because of mutual misunderstandings between geologists and pedologists. Lev S. Berg is the ‘only begetter’ of the theory, first proposed in 1916, and propagated throughout his life. R.J. Russell proposed the same approach to the loess in the Lower Mississippi valley in his famous 1944 paper, which contributed enormously to the study of loess in North America. As understanding of the various processes involved in the formation of loess deposits has developed, a compromise position on loess formation has become possible. The major intrinsic features of loess deposits are the open structure and the collapsibility. It appears that the open structure is caused by aeolian depositional processes and the collapsibility is caused by loessification processes. The compromise was initiated by Marton Pécsi in 1990, He endeavoured to retain a loessification aspect in the study of loess deposits, as the subject appeared to be overwhelmed by the aeolian idea system promoted by geologists; it has been mostly a Central European endeavour. The history of the concept of loessification largely involves (1) its development in Russia, (2) its dissemination and discussion – and attempts at refutation and modification – in the wider world.