This paper describes a complex suite of Plio-Pleistocene calcretes which developed in alluvial fan and fluvial gravels in the Tabernas Basin, Almería Province. The geochemistry, macro- and micromorphological properties and geomorphological positions
of the different calcrete units are discussed, and, on the basis of this information, their mode of origin suggested. Calcrete genesis is subsequently considered in the context of the reconstruction of the early phases of landscape development within the Tabernas
Quaternary sedimentation in the Moshaweng dry valley of southeastern Botswana is evaluated on the basis of geomorphological evolution and sedimentological analyses. Stratigraphic evidence reveals an upper surface containing abundant sil-calcrete
, an intermediate surface in which sil-calcrete underlies nodular calcrete and lower surface in which sil-calcrete and nodular calcrete are interbedded. This subdivision is reflected in the geochemical composition of the sediments. The AA. aim to enhance
Geomorphology and pedogenic evolution of Quaternary calcretes in the northern Adana Basin of southern Turkey
Etude de la situation géomorphologique des calcrètes et des horizons columnaires par rapport aux sols dans le nord du Bassin d'Adana. Les calcrètes et les horizons à colonnes témoignent des fluctuations climatiques pléistocènes. Présentation d'une
séquence complète de la formation des calcrètes à partir des sols.
Fan-surface dynamics and biogenic calcrete development : interactions during ultimate phases of fan evolution in the semiarid SE Spain (Murcia)
Alluvial cone ; Arid area ; Biogenic process ; Calcrete ; Microstructure ; Murcia ; Pedogenesis ; Petrography ; Quaternary ; Semi-arid area ; Spain
This paper describes different calcrete profiles developed on middle-late Pleistocene fan surfaces from SE Spain (Campo de Cartagena, Murcia). The results obtained in this study came from an integrated petrological and geomorphological analysis
of calcretes profiles and fan surfaces. The occurrence of many features indicate the biogenic origin of the calcretes, mainly induced by plant root related microbial activity. Development of the calcrete profiles took place in 6 main stages and was driven
This paper presents the first in-depth investigation of cement relationships within Kalahari silcrete-calcrete intergrade duricrusts at a profile scale, through the detailed analysis of the petrology and geochemistry of duricrusts and bedrock
. It also serves to reinforce the significance of topographic depressions (pans and valleys) upon the formation of calcrete, silcrete and calcrete-silcrete intergrade duricrusts within the Kalahari.
Characteristics, evolution and distribution of Quaternary channel calcretes, southern Jordan
Arid area ; Calcrete ; Climatic variation ; Fluvial processes ; Groundwater ; Jordan ; Micromorphology ; Phreatic ground water ; Quaternary ; Sedimentology ; Spatial distribution ; Stream
This paper concentrates on the macromorphological and micromorphological characteristics of non-pedogenic channel calcretes preserved in the Wadi Dana. The geomorphological and sedimentological characteristics are studied and related to processes
operating in the present-day wadi system. The products of calcretization have been observed to see if the cement patterns and types are uniform or if variations exist spatially and temporally. Calcrete formation has been occurring over significant periods
U-series dating of immature and mature calcretes as a basis for constructing Quaternary landform chronologies for the Sorbas basin, southeast Spain
Almería ; Arid area ; Calcrete ; Fluvial terrace ; Geochronology ; Quaternary ; Spain ; Th/U dating
Immature and mature calcretes from an alluvial terrace sequence in the Sorbas basin were dated by the U-series isochron technique. By using this technique to date calcretes that have formed during terrace aggradation and at the terrace surface after
more reliably than any currently used geochronological procedure and is appropriate for dating terrace sequences in dryland regions worlwide, wherever calcrete horizons are present.
Calcretes and cryogenic structures in the area of Puerto Madryn (Chubut, Patagonia, Argentina)
Aeolian features ; Argentina ; Calcrete ; Frost action ; Geomorphogenesis ; Grain size distribution ; Ice wedge ; Microstructure ; Patagonia ; Quaternary ; Surface deposits
Calcretes closely linked with fossil ice-wedge pseudomorphs in Pleistocene alluvial deposits are widespread in Patagonia from Rio Negro to Rio Gallegos. As carbonate rocks are absent in the region, the questions to be asked are: where did
Rare earth and other trace and major elemental distribution in a pedogenic calcrete profile (Slimene, NE Tunisia)
Arid area ; Calcrete ; Clay mineral ; Geochemistry ; Iron ; Mineralogy ; Pedogenesis ; Semi-arid area ; Trace-element ; Tunisia ; Weathering
A calcrete profile developed on the top of a calcareous consolidated dune located in a coastal area of NE Tunisia (semi-arid climate) was studied with the aim to investigate the behavior of the chemical elements (rare earth elements—REE—and other
trace and major elements) during the processes associated with calcrete formation, particularly dissolution and precipitation of carbonates in the vadose zone. The profile shows a vertical sequence, with clear zonations from the surface downwards
: a reddish soil at the land surface, a nodular horizon, a laminar-structured level, and the consolidated old dune. The most significant chemical variations associated with the calcrete formation are : enrichment of Co, U, Br, and REE in calcrete; MREE
depletion near surface, particularly Eu, MREE and HREE enrichment in calcrete; Hf, Zr, Cr, Th, Cs, Ta, Ga, Rb, K retained near surface where calcite was dissolved. Fe is more reduced at surface. The ratio goethite/hematite increases downwards.
Calcretes and their decalcification around Rundu, Okavangoland, South West Africa in Palaeoecology of Africa and the surrounding islands. Volume 15. Southern African Society for Quaternary research. Proceedings.
Pedocretes occurring around Rundu, Okavangoland, South West Africa/Namibia show all gradations between calcrete and silcrete. Certain calcrete-like materials containing no carbonate are interpreted as representing decalcified, silicified calcretes
. The last major period of calcrete formation probably took place at least 14 000 years BP, under a climate drier than the present, between the close of the Middle Stone Age and the last major aeolian redistribution of the sands of Kalahari type
. The pedogenetic processes currently operative in the area favour decalcification and possibly silicification rather than significant near-surface calcrete formation.
In this paper, the AA. attempt to construct a detailed terrestrial late Pleistocene climatic record in India by studying oxygen and carbon stable isotopes in pedogenic calcrete from the Thar Desert. The nearly continuous calcrete record in eolian
Vadose diagenesis and multiple calcrete soil profile development in Hutt Lagoon area, Western Australia
Australie ; Calcrète ; Diagenèse vadose ; Géographie de l'Océanie ; Hutt Lagoon ; Littoral ; Profil pédologique ; Sédimentologie ; Western Australia
Grâce à de récentes campagnes de recherche de minéraux lourds et à l'exploitation des sables le long des marges terrestres du Lagon Hutt, en Australie occidentale, plusieurs horizons de calcrètes vadoses ont été amenés à l'affleurement. Ils se sont
formés dans l'unité sableuse de Bishop Gully d'âge holocène. Ces horizons pédologiques se répètent dans un intervalle stratigraphique relativement court, formant des profils pédologiques à calcrètes multiples.
Calcretes are widespread in the Adana region. X-ray powder diffractometry (XRD), scanning electron microscopy and energy-dispersive analyses (SEM-EDX) and differential thermal analysis-thermal gravimetry (DTA-TG) reveal that calcretes and their host
-rock mudstones are composed predominantly of calcite and smectite, respectively. The results suggest a pedogenic origin for calcretes. The AA. estimate environmental conditions for calcrete formation : under the C3-dominated vegetation cover
Observations on calcrete and recent calcic horizons in relation to landforms, central Namib desert in Palaeoecology of Africa and the surrounding islands. Volume 15. Southern African Society for Quaternary research. Proceedings.
Observations on ancient and recent calcretes, both of pedogenic and non-pedogenic origin are presented. A proper identification of the calcretes in relation to their position in the landscape is shown to be of considerable help in reconstructing
The aim of this study was to examine pedogenic formations consisting of massive and paleosolic caliches (calcrete) in the Misis area, and to correlate these units with the underlying strata of the lithological sequence of the Tertiary Adana Basin.
Different amounts of pedogenic palygorskite in South West African Cenozoic calcretes : geomorphological, paleoclimatical and methodological implications
Africa ; Arid area ; Botswana ; Calcrete ; Cenozoic ; Clay mineral ; Geochemistry ; Namibia ; Palaeoclimatology ; Pedogenesis ; Quaternary ; South Africa
En Afrique du Sud-Ouest (Namibie, Botswana Ouest, République d'Afrique du Sud, Sud-Ouest) la palygorskite est le minéral dominant de la fraction argileuse dans les calcretes du Tertiaire. Dans les calcretes du Quaternaire, le rapport entre la
palygorskite et les autres minéraux argileux s'inverse (dominance illite/micas). Ceci peut s'expliquer en fonction des différentes sources de carbonate, et de la disponibilité du Mg au cours des processus de formation des calcretes. La connaissance des
Palustrine carbonates and pedogenic calcretes in the Çal basin of SW Anatolia : Implications for the Plio-Pleistocene regional climatic pattern in the eastern Mediterranean
Sedimentologic and stable isotopic studies in the Çal basin-fill provide new insights on the late Neogene–Quaternary climatic pattern in the eastern Mediterranean. An erosional unconformity separates the Pleistocene siliciclastic and calcrete
deposits above as a single sedimentary unit resting on top of floodplain fines and restricted to the basin center. The stable isotopic analysis of the palustrine carbonates and pedogenic calcretes displays a wide range of values and the lack of significant
δ18 O-δ13 C may indicate subhumid conditions or significant diagenetic alteration. The δ13 C values of these carbonates, organic δ13 C data from calcretes and floral remains indicate that the landscapes were dominated by C3 forest plants.
Australia ; Calcrete ; Doline ; Dune ; Fracture ; Karst ; Karstification ; Pleistocene ; South Australia
A field of Middle and Late Pleistocene coastal foredunes occupies much of western Eyre Peninsula, South Australia. The rolling surface reflects the morphology of the stacks of calcarenite dunes that underlie the area. Hardpan calcrete is well
developed in relation to the present, as well as to earlier dune surfaces. The region is a typical karst. Some dolines, including several of the larger forms occur high in the local topography and are also aligned in groups. Low permeability calcrete