Le district aurifère de Challant (Val d'Aoste-Italie) : gîtologie, géochimie et métallogénie de l'or

In the auriferous Monte Rosa Province , the Challant district appears as a geological unit and is situated near the Arcesa island. These rocks are paleozoic gneiss surrounded by the Piemonte ophiolite nappe. The district extends South of Ranzola major fault which is the North limit of gneiss . They are typical epigenetic lodes : it may be assumed that their period of deposition fell between 50 and 30 My. It is possible to range the hundred of deposits in two types : quartz, native gold and low sulfides (mean gold grade 12 g/t), quartz and pyrite (mean gold grade 7g/t) . We may assume that the gold stores equal at least 1 t , and possibly even 5 t . Various analytical methods have been used such as Spark Source Mass Spectrometrywe have studied all elements (major, minor and trace) in gneiss, quartz , native gold, listvenites and pyrites coming from differents deposits. Auriferous pyrites are easily distinguished from non auriferous pyrites on the basis of trace elements . In this district, some trace elements such as Sb, As, Ag, Cu , Hg, Bi, Te may be gold indicators and their use in systematic soil prospection is proposed . From geological, ore deposit and geochemical data, a secretion metamorphic origin for gold of the Challant district is discussed.

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Source https://theses.hal.science/tel-00741254
Author Richard, Annick
Maintainer CCSD
Last Updated October 31, 2026, 03:27 (UTC)
Created October 31, 2026, 03:27 (UTC)
Identifier tel-00741254
Language fr
Rights https://about.hal.science/hal-authorisation-v1/
contributor Laboratoire de Géodynamique des Chaines Alpines (LGCA) ; Observatoire des Sciences de l'Univers de Grenoble (OSUG) ; Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
creator Richard, Annick
date 1981-04-25T00:00:00
harvest_object_id 9799b184-6319-4a5a-a1bf-1a8fadece945
harvest_source_id 3374d638-d20b-4672-ba96-a23232d55657
harvest_source_title test moissonnage SELUNE
metadata_modified 2025-09-27T00:00:00
set_spec type:THESE