The Baie-à-Cadie mafic-ultramafic intrusion is located near the Lac St-Jean anorthosite in the central portion of the Grenville Province. The age of the intrusion is 1150 Ma, which is similar to the age of the Lac St-Jean anorthosite (1140 Ma to 1160 Ma). There are two nickel-copper sulphide occurrences at the margins of the intrusion. Given the recent discovery of the Voisey's Bay Ni-Cu sulphide deposit in a very similar context, the origin of the Baie-à-Cadie sulphide showings has been investigated.The sulphides occur in three forms: disseminated sulphides in the form of interstitial masses between silicate minerals, disseminated sulphides in the form sulphide bubbles averaging 3 cm in a silicate matrix and finally, in the form of a massive sulphide pod (1x2 m) at the Dumont showing. The main sulphide minerals are pyrrhotite, pentlandite and chalcopyrite. The silicate host rock is a gabbronorite. The rocks containing disseminated sulphides have an average of 0.2 % Ni, 0.1 % Cu and 0.2 ppm Pt+Pd . The massive sulphide contain 2.8 % Ni, 1.1 % Cu and 1 ppm Pt+Pd.The model for the formation of magmatic sulphide deposits involves four steps; 1) partial melting of the mantle at sufficiently high degree to absorb all the sulphides in the mantle and thus release the metals to the magma, 2) rapid transport of the magma to the site of emplacement in order that no sulphides segregate en route, 3) sulphide saturation of the magma, possibly caused by its contamination by partial melts of the country rock, 4) collection of the sulphides in sufficiently large quantities to form an ore deposit. Applying this model to the Baie-à-Cadie showings, the following conclusions were reached.The gabbronorite margins of the intrusion are interpreted to represent the parental magma. The major elements indicate that this magma is tholeiitic. The forsterite content of the olivines in the harzburgites (Fo86) indicates that the magma was MgO-rich but the rocks have negative Ta anomalies and positive Th anomalies. The composition can be modelled by assuming that the gabbro formed from a tholeiitic picrite, which was contaminated with 10% of the host paragneiss. The picrite would have provided a Ni-PGE-rich magma. The location of the sulphides at the margins of the intrusion and the negative Ta anomalies suggest that the assimilation of the paragneiss was responsible for triggering sulphide saturation in the magma. The sulphides collected metals but only in rare cases have the sulphides accumulated sufficiently to form massive sulphides and collected sufficient metals to form a deposit. It seems that the process was interrupted before the sulphides had a chance to accumulate. The sulphides in the gabbronorites at the site of the occurrences show depletion in PGE relative to Ni and Cu. A tectonic context that is unfavourable to a quick and easy rise of the magma could be responsible for this characteristic. The magma could have lost a first fraction of sulphide that preferentially subtracted PGE. m REMERCIEMENTS La rédaction de ce mémoi...

Multinationals affirm corporate social responsibility (CSR) is a way to go further than national and international law to build a social compact. While CSR can contribute to an effective global labor governance scheme, we argue that national and international laws must be engaged to regulate CSR private governance schemes. We will support this argument and, furthermore, we will argue that international trade agreements can provide, if effectively enforced, grounds for the articulation. It can be argued that hybrid governance schemes could ensure that result-oriented and pragmatic developmental processes are at the core of the CSR–development nexus. In this article, we argue for the need to socialize CSR to make it more efficient, and that trade agreements can be part of this process. CSR is not an autonomous regulatory trajectory, and it will probably become increasingly regulated through institutional means.

No abstract