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A micrornorphological approach, based upon sets of closely-spaced thin sections taken from three sites located along a climatic and depositional gradient, has been utilised to reconstruct the sequence of pedogenic and sedimentary events leading to the development of the S1 paleosol in northwest China. Two main pedosedimentary stages related to regional changes in monsoonal controls are evident at...
At four study sites in northern Missouri the Farmdale and Sangamon paleosols, which are developed in loess, are welded to the underlying Yarmouth paleosol, developed in till. Upon initial examination, however, they appear to be a single, thick, continuous gleyed horizon (Gleysol). Along flat tabular drainage divides this welded solum is gleyed and is identical in all respects with the historical definition...
Two chronosequences of deep red soils, located in Southern Fezzan, are described micromorphologically. The oldest member is probably Late Tertiary in age and has lateritoid characteristics. The intermediate member, of Middle Pleistocene age, displays moderate rubification and much illuvial clay. The most recent member, of Early Holocene age, has weak rubification and very little illuvial clay. The...
The record of paleoenvironmental change retained within thin sections from loess-paleosol sequences is discussed with reference to case studies from western Europe, China and northwestern USA. The paleoenvironmental significance of individual micromorphological features such as calcitic concentrations, clay coatings and cryogenic structures are first evaluated, and the value of recognising and interpreting...
Paleosols are soils that formed on landscapes of the geologic past. Three kinds exist - buried, exhumed, and relict. To help reconstruct paleoenvironments and for ease of comparison, we suggest a property-based classification system linked to genetic processes. We use enduring properties because alteration of paleosols following burial is common. Morphological properties such as horizonation, soil...
Four representative profiles of poorly developed soils on consolidated material were studied in the Sierra de Carrascoy (SE Spain). The soils, with A-A/R or A-C/R type profiles, have medium-low contents of organic carbon and nitrogen, and calcium carbonate occurs in only one of the profiles. The pH in aqueous suspension is slightly alkaline. The cation exchange capacity is medium-low, but varies slightly...
The soils of Galicia, NW Spain, developed on gabbro often include one or more buried profiles. In the modern overlying soil, gibbsite is common and the Fe oxyhydroxides include maghemite. In the buried soil interstratified kaolinite-smectite is abundant, gibbsite is present in traces and the Fe oxyhydroxides are mostly formed by goethite. Chemical and mineralogical data show that the modern soil has...
Due to northwestward attenuation of the summer monsoon and northwestward intensification of loess deposition during the last interglacial, the last interglacial pedocomplex S1 gradually differentiated from the northwest to the southeast. The three paleosols (S1S1, S1S2, S1S3) corresponding to the marine isotope sub-stages 5a, 5c, and 5e and the two intercalated loess units (S1L1, S1L2) corresponding...
In a semi-arid, upland setting on the Colorado Plateau that is underlain by nutrient-poor Paleozoic eolian sandstone, alternating episodes of dune activity and soil formation during the late Pleistocene and Holocene have produced dominantly sandy deposits that support grass and shrub communities. These deposits also contain eolian dust, especially in paleosols. Eolian dust in these deposits is indicated...
Colluvial deposits consisting of silts and loams were detected in several climatologically different areas of NE Tibet (3200–3700 m a.s.l.). Layering, distinct organic content and low content of coarse matter as well as location in the relief revealed an origin from low-energy slope erosion (hillwash). Underlying and intercalated paleosols were classified as Chernozems, Phaeozems, Regosols and Fluvisols...
This study documents the mineralogical and geochemical record of a lateritic weathering event during the Pliocene in South-west Spain. The paleoweathering profile derived from arkosic sands and comprises a white sandy clayey saprolite, a red mottled clay zone overlain by a thick soft layer, and a ferruginous pisolitic hardcap partially dismantled by erosive processes. Kaolinite, quartz and degraded...
Hematite is an important iron oxide mineral in loess–paleosol sequences in northwest China. Samples containing hematite and related minerals in the loess and paleosol units from Chinese Loess Plateau were investigated using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and high resolution transmission microscopy (HRTEM). The results show that there are at least three genetic...
Geomorphological and sedimentological investigations in the lower reaches of the Orkhon River in northern Mongolia provide evidence for Late Pleistocene terraces, Holocene soil development, aeolian accumulation, soil erosion and slope wash. Optically stimulated luminescence (OSL) and radiocarbon dating of aeolian and colluvial sediments including paleosols show different sedimentation and soil formation...
It is disputed whether Terrae Rossae form mainly out of the bedrock residue, from allochthonous material like aerosols, or by isovolumetric replacement. Furthermore, whether they are mainly relic soils or are still forming is subject to debate. These questions were addressed by comparing the geochemistry of several limestone and basalt based Red Mediterranean Soils with Lithosols on sandstone and...
Carbonate nodules at the base of paleosols within Chinese loess are products of pedogenic neoformation and thus have great potential to document the summer monsoon history. Here we present mineralogical and elemental compositions of carbonate nodules from a north–south loess transect of northern China for the last and penultimate interglacials. X-ray diffraction patterns show that the nodules are...
The most prominent paleosol unit in the Chinese Loess Plateau (CLP) is the fifth paleosol complex (S 5 ) with its well-developed very thick and dark colored pedons. To provide more insight in the formation of S 5 and its environmental significance, the pedogenesis and clay mineral transformation in the S 5 of the Wugong section (Shaanxi Province) on the southernmost CLP are...
This study reports the impact of weathering on behavior of rare earth elements (REE) in a coastal lateritic profile developed on Pliocene sediments at mid-latitude location (~37° N), in the Guadalquivir Basin (Spain). It also explores the stable isotope signature of kaolinite providing constraints on paleotemperature and isotopic composition of the ancient meteoric water. The paleoweathering profile...
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