Tracing magma mixing in granite genesis: in situ U–Pb dating and Hf-isotope analysis of zircons

Overlapping Sr–Nd–Hf–O isotopic compositions in Permian mafic enclaves and host granitoids in Alxa Block, NW China: Evidence for crust–mantle interaction and implications for the generation of silicic igneous provinces

“…This scenario could indicate the isotopic equilibration between MMEs and host granitoids. However, the zircon grains, commonly included in other minerals (Bea, 1996), typically retain their original isotopic compositions, suggesting that the MMEs and host granitoids should have different zircon Hf and/or O isotopes if their original magmas had different isotopic signatures (e.g., Griffin et al, 2002;Liu et al, 2013;Sun et al, 2010;Yang et al, 2007). For example, even cryptic mixing can be revealed by in situ zircon Hf-O isotopes (Appleby et al, 2008;Dan et al, 2014c;Kemp et al, 2007).…”

“…It is widely accepted that mafic and felsic microgranular enclaves result from the mixing or mingling of mafic and crustal felsic magmas (e.g., Barbarin, 2005;Blundy and Sparks, 1992;Dorais et al, 1990;Feeley et al, 2008;Sun et al, 2010;Vernon, 1984Vernon, , 1990Wang et al, 2012;Wiebe et al, 1997;Yang et al, 2006Yang et al, , 2007. Two other proposals suggest that they are: (1) fragments of recrystallized, refractory metamorphic rocks or of melt residues from the granite source (e.g., Chappell and White, 1991;Chappell and Wyborn, 2012;Chappell et al, 1987); or (2) cumulates of early-formed crystals or chilled margins (e.g., Bonin, 1991;Collins et al, 2006;Donaire et al, 2005;Shellnutt et al, 2010;Tindle and Pearce, 1983).…”

“…Distinguishing between these scenarios requires the ability to characterize the primary source of both the microgranular enclaves and their host granitoids. Compared with whole rock Sr and Nd isotopic compositions, which are easy equilibrated between the microgranular enclaves and adjacent host granitoids (e.g., Barbarin, 2005;Yang et al, 2007), in situ minerals can retain their initial isotopic compositions. Thus, in situ isotopic analysis is commonly used to trace the origin and petrogenetic processes of microgranular enclaves and granites (e.g., Sun et al, 2010).…”

Hidden Archaean and Palaeoproterozoic crust in NW Ireland? Evidence from zircon Hf isotopic data from granitoid intrusions

“…Use of the Hf isotopic composition of zircon in this way can lead to a more sophisticated understanding of the petrogenesis than is †Author for correspondence: mf@bas.ac.uk possible using the widely employed whole-rock SmNd technique (e.g. Flowerdew et al 2006;Chen et al 2007;Wu et al 2007;Yang et al 2007;Zeh et al 2007).…”

Late Early Cretaceous adakitic granitoids and associated magnesian and potassium‐rich mafic enclaves and dikes in the Tunchang–Fengmu area, Hainan Province (South China): Partial melting of lower crust and mantle, and magma hybridization

“…Mafic enclaves often occur in calc-alkaline, alkaline and even peralkaline granitoids, and have attracted wide interests due to their important role in understanding the origin of the host granitoids, deep crustal composition and geodynamic processes (e.g., Didier, 1973;Vernon, 1984;Holden et al, 1987;Eberz et al, 1990;Bonin, 1991;Didier and Barbarin, 1991;Wiebe et al, 1997;Barbarin, 2005;Schonenberger et al, 2006;Yang et al, 2006Yang et al, , 2007Chen et al, 2009;Shellnutt et al, 2010;Sun et al, 2010). Four main models have been proposed for the formation of the enclaves.…”