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
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.