Volume 10, Number 4, 345-361, DOI: 10.1007/BF00207893

Le gisement plombo-zincifère de Salafossa (Alpes italiennes orientales): Remplissage d'un paléokarst triasique par des sédiments sulfures

Ph. Lagny

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Abstract

The anisian carbonate formations in the Sappada region (Eastern Italian Alps) were emerged and karstified several times during the middle triassic period. The various Zn-Pb-Ba-Fe occurrences appear to be strictly bound to continental dolomitic sediments (black ferroan dolomites), which outline the triassic erosional surfaces. In this regional environment, the Salafossa Pb-Zn deposit occurs in a peculiar site corresponding to the longest emersion: it is located, along a triassic fault, in an area where the anisian dolomites are directly covered by the transgressive ladino-carnian dolomites. This fault allowed the formation of an important underground cavities network, partly collapsed. The analysis of the mineralized karst infillings shows, in relation with the voids shape, clear vertical variations of facies and paragenesis. The sulphide sediments deposited in the quiet and confined waters of the karstic network, progressively sunk during the rising of the base level, in relation with the marine transgression on the margin of the emerged area.

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