RENAC , Christophe

Structure- and tectonic-related gas migration into Ordovician sandstone reservoirs and its impact on diagenesis history were reconstructed in two fields in the Sbaa Basin, in SW Algeria. This was accomplished by petrographical observations, fluid inclusion microthermometry and stable isotope geochemistry on quartz, dickite and carbonate cements...

European Tertiary sedimentary basins as the Forez Graben, France, are potential records of continental paleoclimates. The Forez Basin hosts deposited and precipitated sediments of Oligocene to Miocene age. Geochemical data of carbonates indicate strictly continental origin starting at Eocene-Oligocene with tropical to temperate climate...

Sedimentary successions of palustrine deposits from the Forez Graben recorded changes in depositional and hydrological conditions throughout the Middle to Late Miocene of France. Paleontological, mineralogical and geochemical data combined with mass-balance calculation allowed the identification of modern, diagenetic and eogenetic stages of...

Volcanic rocks from the Maghnia region of northwest Algeria consist of fresh to altered rhyolitic units that were emplaced during late Miocene time. Petrographic observations and geochemical data indicate that rhyolitic rocks were derived from a hybridized peraluminous magma. Petrogenetic modeling, REE contents and oxygen isotope data of quartz...

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Identifying the source, origin and time of emplacement of copper and gold deposits in the Neoproterozoic volcano-sedimentary and plutonic series of southern Brazil is a longstanding research goal. In this geological context, the Camaquã and Lavras do Sul areas are reported to be a post-collisional domain related to the Braziliano-Pan-African...

Carbonatites are mantle-derived rocks associated with rare earth element deposits and their origin is debated. The majority of carbonatites are found in proximity to old continental crust and generally exhibit more geochemically enriched Sr and Nd isotopes relative to the prevalent mantle, with only a few known carbonatite occurrences found in...

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We investigate the potential of 40Ar-39Ar systematics in secondary K-bearing minerals developed at the expense of hydrothermally altered volcanic pyroxenes from a fossil geothermal system located in the Saintes archipelago (Lesser Antilles magmatic arc).Our work reports the first example of dating hydrothermal muscovite crystallization...

The Seival Mine, located in the Camaquã Basin, hosts several small Cu and Ag ore deposits in volcano–sedimentary sequence surrounding the Lavras do Sul Intrusive Complex. Alteration minerals consist of calcite, sulfate, smectite and chlorite/smectite associated with Cu–rich sulfides. The mass balance calculations from less altered to altered...

The Trepča Pb-Zn-Ag skarn deposit (29 Mt of ore at 3.45% Pb, 2.30% Zn, and 80 g/t Ag) is located in the Kopaonik block of the western Vardar zone, Kosovo. The mineralization, hosted by recrystallized limestone of Upper Triassic age, was structurally and lithologically controlled. Ore deposition is spatially and temporally related with the...

A Mina do Seival é constituída por rochas vulcânicas e diques de composição andesítica e traqui-andesítica, dispostas em duas sequências. A sequência I inclui rochas piroclásticas e efusivas, e a sequência II é representada pelos diques de composição andesítica. Ambas são incluídas na Associação Shoshonítica de Lavras do Sul. Este magmatismo é...

The Neoproterozoic sequence of volcanic rocks in the Camaquã Basin included in the Lavras do Sul Shoshonitic Association hosts disseminated Cu deposits. The volcanic sequence in the Seival Mine area includes andesitic lava flows, lapilli tuff, volcanic agglomerate and andesitic dikes with pervasive alteration. The hydrothermal alteration is...

Abstract The Ain Allega, Mjar Hannech and Sidi Driss Pb‐Zn‐Ba‐Sr‐As‐(Hg) deposits in northern Tunisia are hosted in a post‐nappe anticline with a core of a Triassic evaporite diapir affected by the NE–SW‐trending Ghardimaou‐Cap Serrat and E‐W lineament. The ore minerals show different styles; particularly, impregnation in dolomite, cement of...

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Piaba is an orogenic gold deposit (~ 3.5 Moz) of the São Luís cratonic fragment in north-northeastern Brazil. The deposit is epizonal–mesozonal and associated with the development of a subvertical strike–slip fault that cut across Rhyacian metavolcano-sedimentary rocks and granitoids. The metavolcano-sedimentary sequence comprises...

The Lavras do Sul Au-Cu mining district, southern Brazil, hosts an Ediacaran plutonic-volcanic association with hydrothermal alteration. This association is interpreted as a ca. 600-580 Ma tilted porphyry-epithermal system, where the main ore occurs in phyllic and intermediate argillic halos around quartz veins. In this paper we used detailed...

The Djebel El Hamra Pb-Zn-Ba-Sr (Hg) deposits in northern Tunisia are hosted in a post-nappe anticline with a core of a Triassicevaporite diapir affected by the NE–SW-trending Ghardimaou-Cap Serrat lineament. Three stages of mineralization occurred inthe Triassic dolostone: stages I and II caused alternating deposition of sulfate (Ba, Sr) and...

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