Sources of Cretaceous bimodal volcanic rocks in the coastal region of southeastern China - Constraints of the Sr content and its isotopes

Citation
Gf. Xng et al., Sources of Cretaceous bimodal volcanic rocks in the coastal region of southeastern China - Constraints of the Sr content and its isotopes, ACT GEO S-E, 73(1), 1999, pp. 84-92
Citations number
38
Categorie Soggetti
Earth Sciences
Journal title
ACTA GEOLOGICA SINICA-ENGLISH EDITION
ISSN journal
10009515 → ACNP
Volume
73
Issue
1
Year of publication
1999
Pages
84 - 92
Database
ISI
SICI code
1000-9515(199903)73:1<84:SOCBVR>2.0.ZU;2-Z
Abstract
Cretaceous volcanism in the coastal region of southeastern China was charac teristized by occurrence of bimodal volcanics consisting of basalts and rhy olites, the geneses of which are still controversial. Based on the fact tha t their isotopic compositions are similar but the Sr content of the former is much higher than that of the latter, this paper discusses the respective sources of the two end-member rocks, and concludes that basalts were deriv ed from the subduction-related enriched upper mantle wedge and their isotop ic compositions had not been affected by crustal assimilation, whereas rhyo lites were formed by remelting of the old metamorphic basement, but they we re mixed up with the underplating basaltic magmas to various degrees so tha t their Sr isotopic compositions varied significantly from the sources and tended to be homogeneous to the latter.