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Mineralogical characteristics of terra rossa soils and terra rossa like materials in Istria

Terra rossa in Istria is situated on the Jurassic-Cretaceous-Paleogene carbonate plain and is considered a polygenetic reddish soil which bears typical terra rossa Fe-oxide characteristics (e.g. Fe d and Fe d/Fe t) and might have been created from Pliocene onward during favourable climatic periods (Pliocene, older Pleistocene and interglacial periods of middle and younger Pleistocene). Terra rossa is composed of quartz, plagioclase, K-feldspar, micaceous clay minerals (Illitic material and mica), kaolinites (Kl D and Kl), chlorite, vermiculite, low-charge-vermiculite or high-charge smectite, mixed-layer clay minerals (other than illitic material), hematite, goethite and XRD-amorphous inorganic compound. Calcite, dolomite and boehmite are sporadically present and are of local importance. Kaolinites and illitic material are dominant clay mineral phases in the clay fraction of all terra rossa from Istria. Kaolinite which does not from intercalation compounds with DMSO is the dominant mineral phase in fine clay and is considered predominantly authigenic rather then inherited from parent Materials. Unlike the rerra rossa soils, insoluble limestone and dolomite residue does nog contain plagioclase, vermiculite and kaolinite which does not from intercalation compounds with DMSO (Kl), the dominant mineral phase in the clay fraction is illitic material and kaolinite (Kl D) was found only in some samples. This dana suggests that the insoluble limestone and dolomite residue are only one of the components of the parent material from which the Istrian terra rossa was formed. Most of the analyzed terra rossa samples, as far as their heavy mineral composition is concerned, typically have a large quantity of the epidote mineral group and amphibole. Greater shares of zircon and rutile were found only in a few terra rossa samples. The comparison of the mineral composition (bulk mineralogy, clay mineralogy, heavy mineral fraction) of terra rossa soils, loess and flysch supports external material influence in the genesis of terra rossa. Both loess and flysch sediments have contributed in the genesis of terra rossa

Mineralogical characteristics of terra rossa; soils; terra rossa like materials in Istria

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