Comparative Cr and Mn speciation across a shore-to-reef gradient in lagoon sediments downstream of Cr-rich Ferralsols upon ultramafic rocks in New Caledonia

Author(s):  
Pauline Merrot ◽  
Farid Juillot ◽  
Pierre Le Pape ◽  
Pierre Lefebvre ◽  
Jessica Brest ◽  
...  
1973 ◽  
Vol 110 (5) ◽  
pp. 431-446 ◽  
Author(s):  
K. A. Rodgers

SummaryGranodiorite stocks were intruded into the alpine peridotites of southern New Caledonia in the Eocene following overthrusting of the ultramafics onto the sialic core of the island. Strong zoning, from mela-diorite to granodiorite, is developed in one pluton and is believed to be the result of assimilation of ultramafic and mafic rocks by the calc-alkaline magma. Evidence in favour of a consanguineous relationship between the felsic and ultramafic rocks is largely circumstantial. In their petrography, mineralogy and chemistry, the rocks show few differences from other felsic plutonics of Tertiary age in the southwest Pacific.


2017 ◽  
Vol 550 ◽  
pp. 268-278 ◽  
Author(s):  
Pierre Genthon ◽  
Jean-Lambert Join ◽  
Julie Jeanpert

2020 ◽  
Vol 51 (1) ◽  
pp. 247-277 ◽  
Author(s):  
P. Maurizot ◽  
B. Sevin ◽  
S. Lesimple ◽  
L. Bailly ◽  
M. Iseppi ◽  
...  

AbstractThe main metallic mineral resources of New Caledonia are hosted by the obducted Peridotite Nappe. Ni, Co, Cr and the Pt group elements (PGEs) are specific to this ultramafic terrane. Cr, as podiform chromitite in the uppermost mantle, is the only hypogene metal mined economically in the past. The largest chromitite deposits are located in the lherzolitic Tiébaghi Massif. Supergene Ni and Co deposits are concentrated by the tropical climate that has prevailed since the Miocene. New Caledonian lateritic Ni deposits account for 10% of the global Ni resources. Hydrous Mg silicate and oxide types coexist in a single deposit. A local genetic model based on geomorphological evolution is proposed. Sc is a prospective resource associated with these supergene deposits. The PGEs are a prospective resource associated with chromite, with potential in the hypogene, supergene and fluvio-littoral domains. Pt and Pd are the most significant elements. The transition zone between the upper mantle and crustal cumulates constitutes a regional Pt–Pd-enriched horizon. The concentrations are related to small disseminated chromite lenses in a pyroxene-rich lithology. The PGEs are concentrated in weathering profiles. The value of chromite-rich sands as placers or sand beach deposits might be enhanced by the occurrences of PGEs.


2021 ◽  
Author(s):  
Eric Viollier ◽  
Farid Juillot ◽  
Pauline Merrot ◽  
Jean-Michel Fernandez ◽  
Olivier Radakovitch ◽  
...  

2020 ◽  
Vol 51 (1) ◽  
pp. 215-245 ◽  
Author(s):  
P. Maurizot ◽  
B. Sevin ◽  
S. Lesimple ◽  
J. Collot ◽  
J. Jeanpert ◽  
...  

AbstractThe mineral resources of the non-ultramafic rocks of New Caledonia and its Exclusive Economic Zone can be classified according to their host rocks. The metallic mineral resources are essentially associated with volcanic and magmatic activity. Non-economic volcanogenic massive sulfide deposits with Cu and Au are located in the Late Carboniferous Koh Ophiolite and in the Late Cretaceous Poya Terrane. Base metals, Au and Ag of the sedimentary–exhalative type are present in the metamorphic Diahot-Panié Metamorphic Complex, associated with syn-rift volcanism. An Au–Sb metallogenic province is associated with the post-obduction Late Oligocene granitoids and co-genetic hydrothermal silica–carbonate (listwanite) zones in the Peridotite Nappe; Au is disseminated in the granites and Sb occurs as lodes in the silica–carbonate. Among the non-metallic mineral resources, barite, gypsum, magnesite, phosphate, clays, dimension stones, limestone for use as cement and as a neutralizer, and aggregates are all present. Gemstones such as jade and chrysoprase are only used locally. Late Cretaceous coal, which was briefly exploited in the past, is now considered to be a source rock for an offshore potential oil and gas system. Petroleum prospectivity is currently focused on the Fairway Basin. Several low-enthalpy thermo-mineral springs with a weak geothermal energy potential are known on Grande Terre.


2016 ◽  
Vol 52 (7) ◽  
pp. 945-960 ◽  
Author(s):  
Michel Cathelineau ◽  
Andrey Myagkiy ◽  
Benoit Quesnel ◽  
Marie-Christine Boiron ◽  
Pierre Gautier ◽  
...  

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