Micromorphological approach to polycyclic pedogenesis on the Messak Settafet plateau (central Sahara): Formative processes and palaeoenvironmental significance.
Articolo
Data di Pubblicazione:
2011
Citazione:
Micromorphological approach to polycyclic pedogenesis on the Messak Settafet plateau (central Sahara): Formative processes and palaeoenvironmental significance / A. Zerboni, L. Trombino, M. Cremaschi. - In: GEOMORPHOLOGY. - ISSN 0169-555X. - 125:2(2011), pp. 319-335. [10.1016/j.geomorph.2010.10.015]
Abstract:
The Messak Settafet is a wide plateau located in the Libyan central Sahara (SW Fezzan); it is cut into the
Nubian sandstone and interpreted as relic of a Tertiary peneplain, heavily affected by aeolian deflation.
Notwithstanding degradation phenomena, discontinuous, thin soil bodies are locally preserved below the
hamada. Several profiles, located in correspondence of different geomorphological units (the hamada, the
endorheic depressions, and the southern escarpment), were described and sampled for micropedological
analyses. Micromorphology outlined that the main characteristics of the residual B horizons from each
geomorphological units are (i) high concentration of ferruginous nodules, (ii) multiple generations of clay
illuviation, (iii) fragmentation and deformation of textural pedofeatures, and (iv) calcite mobilization and
redeposition. According to horizon macro- and micromorphological characteristics, these pedologic bodies do
not seem to be in equilibrium with the present-day climatic conditions and should be regarded as paleosols
generated by processes regulated by large water availability and warm temperature, such as rubification, clay
translocation, and calcite redistribution. The development of horizons acted mainly since the Early/Middle
Pleistocene during subsequent pluvial periods and was interrupted by several erosional and aeolian input
phases (arid periods). Pedological processes ended at the onset of the severe dry environmental conditions at
the Mid-Late Holocene transition. The development of this kind of paleosols in the central Sahara is also
discussed in comparison with pedogenetic processes occurring in temperate regions during interglacial and
interstadial intervals.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Central Sahara; Humid periods; Micropedology; Paleosols; Polycyclic pedogenesis; Rubified soils
Elenco autori:
A. Zerboni, L. Trombino, M. Cremaschi
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