St. Pons , Ubaye, France

A classic ww locality for Pb-Cu Sulpho-salts

per la versione italiana clicca QUI

Saint Poins deposit (French Alps of Haute Provence) has been discovered in 1987 and in about ten years of prospecting produced remarkable specimens of Pb-Cu Sulpho-salts; several notes on the deposit have been published during these years on specialised mineralogical magazines:  Mvc-283s.jpg (7856 byte)

Le Regne Mineral (nr. 15 - 1997 ),  Canadian Mineralogist ( Vol. 17 - 1979 ), Mineralogical Record (Vol. 24 - 1993), Rivista Mineralogica Italiana (in course of publication). For some sulpho_salts such as Chalcostibite and Zinkenite, Saint Pons deposit represents the best occurrence worldwide.  Collecting in this area is not easy and requires a deep knowledge of the geological setting of the mineralised siderite lenses as well as of the paragenesis of the different sulpho_salts. The collecting area is very wide also if very few locations provides the better specimens. Mineralisation occurs in siderite lenses embedded into Jurassic "black shales and marls" that outcrop all around in the Barcelonette area.

 

Barcelonette and the Ubaye Valley

   The area is characterised by a remarkable  scenery   and touristic activity is well developed both in winter and  summer period.   Barcelonette village is very characteristic having several buildings of "Liberty" style   built at  the beginning of the XX century   from French emigrants after their return from the immigration country (Mainly Mexico). Mexican flavour is palpable in the Village looking at restaurants, murales and faces of people.ubaye2.jpg (17703 byte)

Emigration from Ubaye area was massive during the  XIX century and it was mainly directed in Central America (Mexico) . Most of the Barcelonette people started fruitful commercial activities in several mexican cities.  Once solved their financial needs they were back in their home country  and built new elegant houses that we may still admire.   

Barcelonette area may be reached from the French Coast or from Haute Provence Route (Sisteron, Gap). Coming from Italy the shortest route is from Cuneo through the Alpine pass of Col de l'Arche.   

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Geology

Barcelonette area is a "tectonic window" where Autochthonous or Para_Autochthonous Jurassic sequences aoutcrop. Due to their characteristics these Jurassic formations are deeply eroded and  shaped in a "bad lands" morphology . Mineralisation occurs randomly distributed in siderite lenses embedded in the Jurassic Sequence. Saint Poins deposit paragenesis may be interpreted as a result of singenethic and epigenetic  events.

 

Prospecting in Saint Pons area

Sulpho-salts occurs in vugs os siderite gangue most of the times filled with Calcite.   Prospecting has to be driven by the presence of siderite lenses. Once a siderite lense has been found we need to evaluate the presence of sulpho_salts mineralisation inside.  Collecting and Prospecting is only possible during dry season (from June to September) when the bad lands area may be easily accessed.

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Main Occurrences 

Boulangerite (Frequent) - Occurs in nice xls sprays on siderite or embedded into calcite. Xls over 1 cm in size have been collected

Bournonite (Rare) - Occurs in nice prismatic xls deeply chanelled and with flat terminations in siderite vugs. Xls up to 1,5 cm have been collected.

Chalcostibite (Rare) - It's the most famous sulpho_salt of the deposit. It Occurs in prismatic xls with complex terminations in siderite vugs. Crystal size may range from few mm to over 10 cm (!!). Saint Pons is the best ww occurence for this rare Sulpho_salt.

Zinkenite (Unfrequent) - Occurs in  prismatic xls with  with cut terminations sometimes forming very aesthetyc globular aggregates. Xls up to 6 cm have been collected.

Dadsonite (Very rare) - This very rare Cl-Sulpho_salt occurs in nice felted or bacillar acicular crystal aggregates encosed in grayish calcite. St.pons occurence probably provides some of the Dadsonite ever collected ww

Tetraedrite (Unfrequent) - Occurs in perfect tethraedrical  xls up to 1 cm associated with Zinckenite and Chalcostibite

Siderite (Common) -  It is the main constituent of the lenses which comprise the gangue enclosing all the other species. It is the most common mineral of Saint Pons Deposit.

By Carlo

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