Naslov
Mn-crust todorokite mineralization on SW backshore Cretaceous limestones from the island of Dugi Otok (Central Adriatic, Croatia)

Autori
Lugović, Boško ; Šegvić, Branimir ; Šegvić, Tanja

Izvornik
Acta Adriatica (0001-5113) 49 (2008), 1; 53-63

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
10-Å manganates ; todorokite ; hydrogenous origin ; pre-Holocene tephra ; Dugi Otok island ; Adriatic

Sažetak
The southwest shore of the island of Dugi Otok is characterised by the unusual sample occurrence of Mn-hydrated oxide mineralization in the form of botryoidally and globular, fine-laminated concentric aggregates, crusting the Upper Cretaceous backshore limestones. The mineralization consists mainly of Fe impoverished 10-Å tecto-manganate todorokite (enriched in Mg and transitional metals) accompanied by accessory MnO∙ OH. Todorokite chemical composition is typical of a hydrogenous origin in an oxic shallow marine environment. According to our model, Mn has been recurrently leached and mobilized from the Late Pleistocene see floor sediments located around 50 nautical miles south the Dugi Otok. We propose a link between the Mn-geochemical anomaly of these sediments and the alteration of distinct, spatial close pre-Holocene tephra, dispersed over the entire recent Adriatic realm.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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