Les zircons des granites océaniques et continentaux: Couplage typologie-géochimie des éléments en traces
Pupin, J.-P. (1992). Les zircons des granites océaniques et continentaux: Couplage typologie-géochimie des éléments en traces. Bull. Soc. Géol. Fr. 163(4): 495-507
In: Bulletin de la Société Géologique de France. Société Géologique de France: Paris. ISSN 0037-9409; e-ISSN 1777-5817, meer
|  |
| Trefwoorden |
Cycles > Chemical cycles > Geochemical cycle
Earth sciences > Geology > Petrology
Earth structure > Earth crust > Continental crust
Earth structure > Earth crust > Oceanic crust
Earth structure > Earth mantle
Minerals > Silicate minerals > Zircon
Rocks > Igneous rocks > Granite
Trace elements
Marien/Kust |
| Abstract |
The coupling of zircon typology together with the distribution of trace elements contents (Hf, Y, Th, U) in crystals, determined after ponctual electron microprobe analyses (and observations with cathodoluminescence), constitutes a fundamental key for the understanding of granitic magma history: source material and protolitic composition, contaminations at different periods of the magmatic stage, role of late fluid phases. Chemical composition of zircon crystals changes as a function of the mantle, hybrid or crustal origin of granitic rocks (oceanic or continental). Oceanic tholeiitic differentiates have specific zircons with low HfO2 (mainly <1%) and high Y contents. In the same way, but less marked, zircon populations from calc-alkaline rocks have early magmatic crystals with low HfO2 (<1.2%) and sometimes high Y contents, systematically absent in crustal rocks (out of inherited nuclei). |
|
