In northern Togo investigations on parent rocks and the lateriticcrusts developed above them were carried out. The question was as to whether or not laterites are suited; as Büdel maintains, to help in the reconstruction of extended planation
levels. It will be shown that the genesis of lateriticcrusts seems to be more dependant on the petrological conditions than had before been assumed. Finally a comparison of the planation surfaces of Togo with the planation chronologies of West Africa
Geochemistry ; Geomorphogenesis ; India ; Laterite ; Micromorphology ; Neogene ; Neotectonics ; Palaeo-environment ; Quaternary ; Tamil Nadu ; Weathering
the lateritisation was not continuous but occurred in phases. Geoarcheological investigations and Quaternary stratigraphical studies date the lateriticcrust surface to the early late Neogene. Neotectonics have played a vital role in shaping the present landscape.
Laterites and lateritic soils around Madras have been formed in different geomorphic conditions and on various geological deposits. They occur as caprocks. Detailed analysis (micromorphological and chemical) and the bore hole litho-log data reveal
The A. argues that Yu. P. Seliverstov made a mistake when relating the Lower Cretaceous surface in Kazakhstan to the Gondvana surface in Africa : in fact it corresponds to the African surface which bears a thick lateriticcrust. The latter is also
erroneously equated by Seliverstov with the Eocene surface in Kazakhstan which bears a thick lateric crust. The latter is also erroneously equated by Seliverstov with the Eocene surface in Kazakhstan which bears only siliceous crust of weathering. - (L'Ed.).
Pedogenesis on the Cranebrook Terrace began about 44 000 BP and has resulted in weathering profiles up to 15 m deep which are characterised by much clay and iron segregation. The dominant clay is kaolinite, and the iron forms nodules, crusts
and pinnacles similar to those of lateritic profiles. This suggests that many lateritic features supposedly indicative of past tropical climates may actually be due to a great duration of processes operating under temperate climates.
The landforms lie at a low altitude in the south-western part of the Sahara and in the Sahel. Some old lateritic duricrusts are still extent on plateaus, especially on the Tagent in central Mauritania. The Continental terminal deposits are coated
with ferruginous duricrusts. During the Quaternary, some ferruginous duricrusts have again been formed in some areas. The landforms are higher and more rugged in South-West Africa (Namibia). But the old surfaces and the glacis have always calcareous crusts
Infiltration through three contrasting biological soil crusts in patterned landscapes in the Negev, Israel
The AA. examine the role of soil crusts in infiltration processes in 3 contrasting environments in the Northern, Central, and Central-Western Negev. The 3 crust types are : a dune sand supporting an almost continuous thin cyanobacterial and moss
crust, a predominantly physically (depositional) crusted loess soil sparsely colonised by cyanobacterial filaments, and a loamy hillslope soil supporting a well-developed crust colonised by cyanobacteria lichens, and some mosses. The AA. examine
the influence of crusts on water flow, and infer likely effects of crusts and their removal on ecological processes in landscapes characterised by a patchy distribution of resources.
Microbiotic crusts in the high equatorial Andes, and their influence on paramo soils
The first part of this paper will discuss the available information on microbiotic crusts, emphasizing their geomorphic and pedological aspects, as well as the sparse existing data for crusts in cold regions. The second part will describe in some
detail the microbiotic crusts found in the high equatorial Venezuelan Andes, as these seem to be the first instance of microbiotic crusts ever described for any high-altitude area in the world.
Laboratory experiments on crust development and rainsplash erosion of loess soils, China
Loess soil samples from Lishi, China, were tested in the laboratory. The objective was to examine the details of the time-dependent process of crust development. Data on splash erosion, crust strength and inference from micromorphological
observations are evaluated. In addition, the effect of crusting in subsequent rainsplash erosion and crust development will be examined as well.
Crusted microtopography on badland slopes in southeast Spain
Four crust types have been recognised on badland slopes developed in Miocene marine marls of the Guadix-Baza depression. The pediment crust, is depositional in origine and is found on the surface of gently sloping pediments flanking the steep
badland slopes. The other three crust types, domed, tower and pinnacle developed in sequence on the steep gully side slopes. An integral part of the crust development sequence is the progressive colonisation of the surface by blue-green algae and lichen