Geochemical Evidence for Mantle Origin and Crustal Processes in ...

JOURNAL OF PETROLOGY VOLUME 46 NUMBER 6 JUNE 2005
Fig. 11. 87 Sr/ 86 Sr vs e Nd diagrams for 18 Popocatépetl samples, including two granodiorite (Gd) xenoliths and two monogenetic SCVF cones
(data from Table 4). (a) Detailed plot showing the isotopic variation of different Popocatépetl units in comparison with other monogenetic SCVF
cones [data from Siebe et al. (2004b)] and Nevado de Toluca stratovolcano [data from Martínez-Serrano et al. (2004)]. Popocatépetl isotopic data
from Boudal (1985) are also plotted. (b) Expanded diagram showing in addition Sr–Nd isotope ratios from metasedimentary Popocatépetl
xenoliths (skarn, metasandstone, and marble) together with data from the Southern Volcanic Zone (SVZ) of the Andes [data from Hickey et al.
(1986)]. Nd assimilation of skarn xenolith 9463A is discussed in the text.
scoria samples from the January 22, 2001 pyroclasticflow
deposit (sample 0102 s) displays anomalously
enriched Pb isotopic ratios ( 206 Pb/ 204 Pb 1878;
207 Pb/ 206 Pb 1567; Fig. 12b). Because this is the
only sample with such characteristics, it is difficult to
determine whether these enriched values are truly
representative or related to small-scale heterogeneities
in the dome lava. A field for East Pacific Rise (EPR)
mid-ocean ridge basalts (MORB) from Zindler & Hart
(1986) and a field for Cocos Plate marine sediments
recovered by the Deep Sea Drilling Project (DSDP) at
sites 467 and 488 (Verma, 2000) are also shown in
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