Zircon trace element constrains on the link between volcanism and plutonism in SE-China

Beitrag in einer Fachzeitschrift


Details zur Publikation

Autorinnen und Autoren: Yan LL, He Z, Beier C, Klemd R
Zeitschrift: Lithos
Jahr der Veröffentlichung: 2018
Heftnummer: 320-321
Seitenbereich: 28-34
ISSN: 0024-4937
Sprache: Englisch


Abstract

Trace elements in igneous zircon crystals are variable within single crystals or amongst populations of crystals and are particularly sensitive to changes in melt composition. In this study, we present zircon trace element data from both volcanic and plutonic rocks of the Yandangshan caldera complex from SEChina. The erupted rhyolitic rocks are interpreted to represent the most differentiated magma, whereas the intruded porphyritic quartz syenites are thought to be representative of the residual crystal mush. The zircon crystals of both lithologies are subdivided into two types based on their internal structures: type A with a distinct oscillatory growth zoning and type B crystals are bright in cathodoluminescence (CL-bright). Type B zircon occurs as rims of type A zircon or as individual grains. Compared to type A, type B zircons commonly show lower Hf, U, Th and Y concentrations and higher Ti and Zr/Hf and Eu/Eu* ratios. The zircon trace element compositions of the volcanic samples generally overlap those of the intracaldera porphyritic quartz syenite and mafic microgranular enclaves that contain both type A and type B zircons. Despite a general overlap, zircon grains from the volcanic rocks show relatively higher Hf contents and Y/Dy ratios, lower Ti contents and Th/U ratios and larger negative Eu anomalies than the plutonic samples. We suggest that the inter- and intragrain compositional variability of zircon crystals can be used to track the evolution of magmatic systems. We show that in our case, the volcanic and plutonic rocks crystallized continuously during the magmatic evolution in a common magma system and that the magmas of these rocks may be linked by fractional crystallization. Furthermore, the type B zircon grains are inferred to have crystalized in relatively hot and less evolved magma indicating a magma recharge event. Consequently, the geochemical variability of igneous zircon crystals can be used to infer on the magmatic evolution of single volcanic system which may also be applicable in other geodynamic environments.


FAU-Autorinnen und Autoren / FAU-Herausgeberinnen und Herausgeber

Beier, Christoph PD Dr.
Lehrstuhl für Endogene Geodynamik
Klemd, Reiner Prof. Dr.
Professur für Geochemie und Lagerstättenkunde


Einrichtungen weiterer Autorinnen und Autoren

Chinese Academy of Geological Sciences (CAGS) / 中国地质科学院


Zitierweisen

APA:
Yan, L.L., He, Z., Beier, C., & Klemd, R. (2018). Zircon trace element constrains on the link between volcanism and plutonism in SE-China. Lithos, 320-321, 28-34. https://dx.doi.org/10.1016/j.lithos.2018.08.040

MLA:
Yan, Lili Li, et al. "Zircon trace element constrains on the link between volcanism and plutonism in SE-China." Lithos 320-321 (2018): 28-34.

BibTeX: 

Zuletzt aktualisiert 2019-20-05 um 20:23