Publication details
Vertical zonality of fractionated granite plutons reflected in zircon chemistry: the Cinovec A-type versus the Beauvoir S-type suite
| Authors | |
|---|---|
| Year of publication | 2012 |
| Type | Article in Periodical |
| Magazine / Source | Geologica Carpathica |
| MU Faculty or unit | |
| Citation | |
| Doi | http://dx.doi.org/10.2478/v10096-012-0030-6 |
| Field | Geochemistry |
| Keywords | zircon; Cinovec; Beauvoir; trace elements analyses; S-type granite; A-type granite; fractionation |
| Description | Vertical changes in chemical composition of zircon vere studied on examples of the strongly peraluminous S-type Beauvoir granite (Massif Central, France, 800 m long borehole GPF-1) and the slightly peraluminous A-type Cínovec granite (Krušné hory Mts./Erzgebirge, Czech Republic/Germany, 1596 m long borehole CS-1). At Beauvoir, zircon shows increase in Hf-content from 2-4 wt% HfO2 in the deepest B3-unit to 15-19 wt% HfO2 in the uppermost B1-unit. The highest contents of F, P, and U were detected in the intermediate unit B2 at a depth of 400-600 m. At Cínovec, Hf shows only moderate enrichment from ca 2 wt% HfO2 in the deeper protolithionite granite to 5-10 wt% HfO2 in the uppermost part of the zinnwaldite granite. Extreme enrichment of outer zones of zircon crystals with Hf or high contents of Th, U, REE, Y and Nb are not considered to be a specific phenomenon characterizing melts of A- or S-type granite, but reflects a high degree of fractionation of systems rich in Na and F. |