Complex soil mass redistribution along a catena using meteoric and in-situ 10Be as tracers

Author(s):  
Francesca Calitri ◽  
Markus Egli ◽  
Michael Sommer ◽  
Dmitry Tikhomirov ◽  
Marcus Christl

<p><span>In hilly and mountainous landscapes, the bedrock is actively converted to a continuous soil mantle. The bedrock-soil interface lowers spatially at the soil production rate, and the soil acts as a layer removing sediment produced locally and transported from upslope. Forested soils of a hummocky ground moraine landscape in Northern Germany exhibit strongly varying soil thicknesses with very shallow soils on crest positions and buried soils at the footslope. We explored the explanatory power of both <sup>10</sup>Be forms (in situ and meteoric) for forest soils on a hillslope to shed light into the </span><span>complex mass redistribution. </span><span>Our main research questions were: how do meteoric and in-situ <sup>10</sup>Be compare to each other? What do they really indicate in terms of soil processes (erosion, sedimentation, reworking)? </span><span>By using both types of <sup>10</sup>Be, the dynamics of soils and related mass transports should be better traceable</span><span>. Both <sup>10</sup>Be forms were measured along three profiles at different slope positions: Hydro1 (summit), Hydro3 (shoulder), Hydro4 (backslope). Furthermore, a buried horizon was found in the profile Hydro4 at 160 cm depth and <sup>14</sup>C-dated. The distribution pattern of meteoric <sup>10</sup>Be of Hydro4 shows an inverse exponential depth profile, and an almost uniform content of in-situ <sup>10</sup>Be along the profile. Meteoric <sup>10</sup>Be indicates on the one hand that a new soil was put on top of an older, now buried soil. On the other hand, meteoric <sup>10</sup>Be is involved in pedogenetic processes and clearly exhibits clay eluviation in the topsoil and clay illuviation in the subsoil. The uniform content of the in situ <sup>10</sup>Be shows soil mixing that must have occurred during erosion and sedimentation. The<sup>14</sup>C dated buried soil horizon indicates a deposition of eroded soil material about 7 ka BP. Consequently, an increase in the in-situ <sup>10</sup>Be content towards the surface should be expect which however was not the case. The reason for this is so far unknown. Radiocarbon dating and <sup>10</sup>Be data demonstrate that strong events of soil mass redistribution in Melzower Forest are mainly a result of ancient natural events. Further measurements of fallout radionuclides (<sup>239+240</sup>Pu) showed no erosion for the last few decades in the same catchment.</span></p>

Author(s):  
Francesca Calitri ◽  
Michael Sommer ◽  
W. Marijn van der Meij ◽  
Dmitry Tikhomirov ◽  
Marcus Christl ◽  
...  

Abstract Purpose Spatial and temporal patterns of past erosional events are a useful and needed information to explain observed soil patterns in different landscapes. Soil thickness reflects the overall expression of pedogenesis and erosion. Forested soils of Northern Germany exhibit varying soil thicknesses with thin soils on crest positions and buried soils at the footslope. The aim of this study is to reconstruct the complex soil mass redistribution and soil patterns of this forested area due to different periods of erosion and stability. Methods We explored the explanatory power of both 10Be (in situ and meteoric) on a hillslope and we 14C-dated buried horizons at different depths. Results The 10Be depth profiles did not show an exponential decrease with depth. They had a ‘bulge’ shape indicating clay translocation and interaction with oxyhydroxydes (meteoric 10Be), bioturbation and soil mass redistribution (in situ 10Be). The combined application of both 10Be and 14C dating revealed progressive and regressive phases of soil evolution. Although Melzower Forest is protected (same vegetation) since the past 250 years, both 10Be clearly indicated major soil mass redistribution along the investigated catena. Conclusion A strong erosion impulse must have occurred between 4.5 and 6.8 kyr BP indicating an earlier human impact on soil erosion than previously postulated (~ 3 kyr earlier). Our findings correlate in fact with the first settlements reported for this region (~ 6.8 kyr BP) and show their immediate effect on soils. The overall soil redistribution rates in this forest are surprisingly similar to those obtained from a nearby agricultural area.


2006 ◽  
Vol 85 (3) ◽  
pp. 197-220 ◽  
Author(s):  
K. Kaiser ◽  
A. Barthelmes ◽  
S. Czakó Pap ◽  
A. Hilgers ◽  
W. Janke ◽  
...  

AbstractA new site with Lateglacial palaeosols covered by 0.8 - 2.4 m thick aeolian sands is presented. The buried soils were subjected to multidisciplinary analyses (pedology, micromorphology, geochronology, dendrology, palynology, macrofossils). The buried soil cover comprises a catena from relatively dry (’Nano’-Podzol, Arenosol) via moist (Histic Gleysol, Gleysol) to wet conditions (Histosol). Dry soils are similar to the so-called Usselo soil, as described from sites in NW Europe and central Poland. The buried soil surface covers ca. 3.4 km2. Pollen analyses date this surface into the late Allerød. Due to a possible contamination by younger carbon, radiocarbon dates are too young. OSL dates indicate that the covering by aeolian sands most probably occurred during the Younger Dryas. Botanical analyses enables the reconstruction of a vegetation pattern typical for the late Allerød. Large wooden remains of pine and birch were recorded.


2017 ◽  
Vol 26 (3) ◽  
pp. 179-190
Author(s):  
Igor Boyko ◽  
Liudmyla Skochko ◽  
Veronica Zhuk

Abstract The interaction features of multi-level retaining walls with soil base were researched by changing their geometric parameters and locality at the plan. During excavation of deep foundation pits it is important to choose the type of constructions which influences on the horizontal displacements. The distance between the levels of retaining walls should be based on the results of numerical modelling. The objective of this paper is to present a comparison between the data of numerical simulations and the results of the in-situ lateral tests of couple piles. The problems have been solved by using the following soil models: Coulomb-Mohr model; model, which is based on the dilatation theory; elastic-plastic model with variable stiffness parameters.


2011 ◽  
Vol 90-93 ◽  
pp. 217-221
Author(s):  
Jin Long Zhou ◽  
Qiao Li ◽  
Wei Zhong Cai

Through the investigation into composition of major shallow foundation soil mass and the correlation of mechanical indicators in this study, the regression equation of mechanical indicators of the features of local foundation soil mass and the data of in situ testing was obtained. Based on massive quantities of exploration materials, this study analyzed engineering features, distribution status, and the feasibility of silty clay to be used as the bearing layer of the pile in Layer ④2 . The analytical results showed that the silty clay with the uniform depth of over 3.5m and the cone tip resistance in static sounding of over 400MPa could be used as bearing layer of the pile. This study could provide the reference for the accurate understanding of the engineering features of soil mass, and the design and evaluation of foundation in Jiaxing City.


1977 ◽  
Vol 14 (12) ◽  
pp. 2824-2857 ◽  
Author(s):  
G. H. Miller ◽  
J. T. Andrews ◽  
S. K. Short

A study of the stratigraphic sequence (14C and amino acid age control), marine bivalve faunal changes, and palynology of buried soils and organic-rich sediment collected from the Clyde Foreland Formation in the extensive cliff sections of the Clyde foreland, eastern Baffin Island, N.W.T., suggests the following last interglacial – Foxe (last glaciation) glacial – present interglacial sequence.(1) Cape Christian Member (ca. 130 000 years BP?)Consists of the Sledgepointer till overlain by the Cape Christian marine sediments. In situ molluscan fauna, collected from the marine sediments, contain a moderately warm bivalve assemblage. A well-developed soil that formed on the marine sediments (Cape Christian soil) contains an interglacial pollen assemblage dominated by dwarf birch. U-series dates of > 115 000 and ca. 130 000 years BP on molluscs from the Cape Christian marine sediments suggest that they were deposited during the last interglaciation, here termed the Cape Christian Interglaciation. The development of a subarctic pollen assemblage in the Cape Christian soil has not been duplicated during the present interglaciation, suggesting higher summer temperatures and perhaps a duration well in excess of 10 000 years for the last interglaciation.(2) Kuvinilk MemberConsists of fossiliferous marine sediments, locally divided by the Clyde till into upper and lower units. The Clyde till was deposited by the earliest and most extensive advance of the Foxe (last) Glaciation. Kuvinilk marine sediments both under- and overlying the Clyde till contain the pecten Chlamys islandicus, indicating that the outlet glacier advanced into a subarctic marine environment. Amino acid ratios from in situ pelecypod shells abovę and below the Clyde till are not statistically different, but contrast markedly with ratios obtained from the same species in the Cape Christian Member. Organic horizons within the Kuvinilk marine sediments contain a relatively rich pollen assemblage, although 'absolute' counts are low.(3) Kogalu Member (> 35 00014C years BP)Sediments of the Kogalu Member unconformably overlie those of the Kuvinilk Member, but are of a similar character. The dominant sediments are marine in origin, but in places are divided into upper and lower units by the Ayr Lake till. Amino acid ratios from in situ shells above and below the Ayr Lake till are indistinguishable, but substantially less than those in the Kuvinilk Member, suggesting the two members are separated by a considerable time interval. Radiocarbon dates on shells in the Kogalu marine sediments range from 33 000 to 47 700 years BP, but these may be only minimum estimates. The sea transgressed to a maximum level 70–80 m asl, coincident with the glacial maximum. Subarctic marine fauna of interstadial–interglacial character occur within the Kogalu marine sediments.(4) Eglinton Member (10 000 years BP to present)A major unconformity exists between the Kogalu and Eglinton Members. Ravenscraig marine sediments were deposited during an early Holocene marine transgression–regression cycle; the oldest dates on these sediments are ca. 10 000 years BP. Locally a vegetation mat occurs at the base or within the Ravenscraig unit. Pollen from these beds is sparse, but indicates a terrestrial vegetation assemblage as diverse as that of today. There is no evidence that Laurentide Ice reached the foreland during the last 30 000 years. Eolian sands that overlie a soil developed on the marine sediments record a late Holocene climatic deterioration. Pollen in organic-rich sediments at the base of, and within, the eolian sands record a vegetation shift in response to climatic change.


Author(s):  
Robert W. Jobson ◽  
Frank Winchell ◽  
A.E. Picarella ◽  
Kiven C. Hill

In northeastern Oklahoma, very little is known about the transition from the Late Archaic to the Woodland period (Wyckoff and Brooks, 1983: 55). To date, most of the archeological evidence documenting this time period has been derived from sites with mixed or otherwise uncertain components. In this report, we present a preliminary description of a small rockshelter, 34RO252, which has a Late Archaic deposit stratigraphically below a Woodland era cultural deposit. These two deposits are unmixed, discrete, and are physically separated by an apparently sterile clay soil horizon. It is anticipated that the stratified cultural deposits at this site will help characterize the transition from the Late Archaic to the Early Woodland period along the Verdigris River in northeast Oklahoma. This site was first reported in April 1994 by two men who had discovered partially exposed human skeletal remains located in the rear remnant of a rockshelter at Oologah Lake in Rogers County, Oklahoma. The two men illegally excavated the remains and removed them from the site. 1 The rockshelter where the remains originated was subsequently examined by the authors and additional skeletal material was identified, in situ, in an exposed soil profile. A series of three radiocarbon assays, described below, placed the cultural deposit and the human remains within the Late Archaic-Woodland period (circa 780 B.C. to A.O. 900).2 This site is provisionally classified as corresponding to a cultural sequence that includes the old Grove C described by Purrington and Vehik.


2021 ◽  
Author(s):  
Georg Guggenberger ◽  
Patrick Liebmann ◽  
Robert Mikutta ◽  
Karsten Kalbitz ◽  
Patrick Wordell-Dietrich ◽  
...  

<p>Formation of mineral-associated organic matter (MAOM) is a decisive process in the stabilization of OM against rapid microbial decomposition and thus in the soils’ role as global carbon (C) sink. Sorption experiments of dissolved OM (DOM) repeatedly showed that particularly mineral subsoils have a large sorption capacity to retain more C. However, there is also an increasing body of literature, revealing an increasing output of dissolved organic C (DOC) from soils. Here, we investigated into this paradox in forest soil under beech by a combination of a field labelling experiment with <sup>13</sup>C-enriched litter with a unique DO<sup>13</sup>C and <sup>13</sup>CO<sub>2</sub> monitoring, an in-situ C exchange experiment with <sup>13</sup>C-coated minerals, and batch sorption experiments.</p><p>Within two years of <sup>13</sup>C monitoring, only 0.5% of litter-derived DO<sup>13</sup>C entered the subsoil, where it was only short-term stabilized by formation of MAOM but prone to fast microbial mineralization. The <sup>13</sup>C monitoring, sorption/desorption experiments in the laboratory, and also the in-situ C exchange on buried soil minerals revealed that there is a frequent exchange of DOM with native OM and a preferential desorption of recently retained OM. Hence, there appeared to be a steady-state equilibrium between C input and output, facilitated by exchange and microbial mineralization of an adopted microbial community. The remobilized OM was also richer in less sorptive carbohydrates. Along with transport of most of DOM along preferential paths, this further increased the discrepancy between laboratory-measured sorption capacities of subsoil and the actual C loading of minerals. Finally, the <sup>13</sup>C labeling experiments revealed that input of fresh litter-derived OM into subsoil may even mobilize old-soil derived OM. Hence, in the field different biogeochemical constraints are acting that prevent that the laboratory-based C sink can be reached in the field.  We conclude, that forest subsoils can hardly be considered as additional C sink, even at management options that increase DOC input to subsoil.</p>


1975 ◽  
Vol 5 (4) ◽  
pp. 551-590 ◽  
Author(s):  
K.W.G. Valentine ◽  
J.B. Dalrymple

Two buried paleocatenas were studied to determine some features and techniques by which buried soils could be recognized, and to define their pedological characteristics, their lateral variation, and their contemporary environment. At Woodhall Spa, Lincolnshire, a ferric podzol to sandy gley sequence was developed in sands under marine clay and fen peat. The peat was radiocarbon dated at about 4100 yr BP. The buried soil was evident from its obvious catenary character and the soil characteristics and contemporary environment were determined using sand mineralogy, micromorphology, and pollen analysis. At West Runton, Norfolk, an apparently similar ferric podzol sequence occurred in Beestonian sands and gravels under a layer of Cromerian organic muds. However, only the uppermost profile contained definite evidence of soil formation. Other lower profiles contained pseudosoil features produced by sedimentation or diagenetic subsurface iron mobilization. It is suggested that the occurrence of a paleocatena is the most important criterion for the identification of a buried soil. Sedimentation and diagenesis cannot reproduce this lateral variation.


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