in this study, micromorphological properties of some samples collected from pedons polluted with petroleum refinery wastes and some adjacent unpolluted pedons were studied. after description of the studied pedons, disturbed and undisturbed samples were collected for physicochemical and micromorphological analyses. the results showed that the physicochemical properties (i.e. structure, bulk dens...

Abstract Caves are usually oligotrophic ecosystems, where the organic matter represents a limiting factor to hypogeal community and sediments often significant energy source. With view identifying input influencing ecological processes occurring in caves, as well potential alteration sources of natural equilibriums, geochemical features several typologies clastic from Pertosa-Auletta Cave (Ital...

Abstract The vast majority of extrusive carbonatites are calcitic rocks which may be confused with sedimentary limestones, thus requiring a disambiguation criterion. Extrusive classified based on quantitative criteria that tend to avoid genetic mechanisms. Carbonatite nomenclature is in progress but regulated by the International Union Geological Sciences norm for igneous rocks. Carbonate rock ...

development of argillic horizon in loess derived soils under xeric and udic soil moisture regimes was studied in golestan province. soils were classified as hapludalfs and haploxeralfs. high leaching, stability of the surface, forest vegetation,structure and well drainage conditions provide appropriate conditions for clay migration through the profile and formation of argillic horizons. in the ...

The carbonate apatite crystals and the segmented structure of the shell plates of the barnacles in the genus Ibla distinguish them from the shell plates of all other barnacles, which are coherent calcitic structures. A detailed study of the hierarchical organization of one of the two shell plate types, the tergum, reveals a remarkably complex structure. Cylinders composed of a chitin-protein co...

The calcitic lenses in the eyes of Palaeozoic trilobites are unique in the animal kingdom, although the use of calcite would have conveyed great advantages for vision in aquatic systems. Calcite lenses are transparent, and due to their high refractive index they would facilitate the focusing of light. In some respects, however, calcite lenses bear evident disadvantages. Birefringence would caus...

Each of two calcitic stalagmites from Grotte de Clamouse, Herault, southern France, displays a discrete aragonite layer dated at around 1100 yr BP. The layer of fanning aragonite ray crystals is immediately preceded by calcite with Mg and Sr compositions that are uniquely high for the past 3 kyr. Trace element compositions close to the boundary between original aragonite and calcite are consist...

The foliated layer of bivalves is constituted by platy calcite crystals, or laths, surrounded by an organic layer, and which are arranged into sheets (folia). Therefore, the foliated microstructure can be considered the calcitic analogue to nacre. In this paper, the foliated microstructure has been studied in detail using electron and X-ray diffraction techniques, together with SEM observations...

For preservation of stones used in Cultural Heritage, affected by weathering processes that threaten their cohesion and mechanical properties, the application of consolidants is a common practice. However, available consolidating products generally exhibit some drawbacks that hinder their performance, in terms of either mechanical efficacy, compatibility with the substrate and/or durability. Et...

The Buxton-Norlim Limeworks southwest of Taung, South Africa, is renowned for the discovery of the first Australopithecus africanus fossil, the 'Taung Child'. The hominin was recovered from a distinctive pink calcrete that contains an abundance of invertebrate ichnofauna belonging to the Coprinisphaera ichnofacies. Here we describe the first fossil bee's nest, attributed to the ichnogenus Celli...