10.6084/m9.figshare.3454745.v1
YONGFENG ZHU
YONGFENG
ZHU
XUAN GUO
XUAN
GUO
BIAO SONG
BIAO
SONG
LIFEI ZHANG
LIFEI
ZHANG
LIBING GU
LIBING
GU
Petrology, Sr–Nd–Hf isotopic geochemistry and zircon chronology of the Late Palaeozoic volcanic rocks in the southwestern
Tianshan Mountains, Xinjiang, NW China
Geological Society of London
2016
ratio
Tianshan Mountains
AFC
mantle
Nd
NW
Devonian basaltic samples
Sr
zircon
Carboniferous basaltic rocks
Geology
2016-06-21 12:19:33
Dataset
https://geolsoc.figshare.com/articles/dataset/Petrology_Sr_Nd_Hf_isotopic_geochemistry_and_zircon_chronology_of_the_Late_Palaeozoic_volcanic_rocks_in_the_southwestern___Tianshan_Mountains_Xinjiang_NW_China/3454745
<p>The Late Palaeozoic volcanic rocks, mainly consisting of basalt, trachyte, trachy-andesite, andesite and rhyolite, widely
distributed in the southwestern Tianshan Mountains, have been proven to be formed during Late Devonian to Late Carboniferous
time (>361–313 Ma) based on zircon sensitive high-resolution ion microprobe dating. The geochemistry demonstrates that the
studied volcanic rocks represent a continental arc formed during the subduction of the Palaeo-southern Tianshan Ocean. The
ε<sub>Hf(T)</sub> values of zircons in these volcanic rocks vary from +1.4 to +15.6 with weighted average values of +9.5 (Late Devonian), +8.9
(Early Carboniferous) and +10.3 (Late Carboniferous), suggesting a depleted mantle origin. However, the Late Devonian basaltic
samples have negative ε<sub>Nd(T)</sub> values (from −5.16 to −3.07) and high initial <sup>87</sup>Sr/<sup>86</sup>Sr ratios (0.7073–0.7098), whereas the Early Carboniferous volcanic rocks mostly have positive ε<sub>Nd(T)</sub> values (from −0.18 to +3.07) with low initial <sup>87</sup>Sr/<sup>86</sup>Sr ratios (0.7044–0.7067), and the Late Carboniferous volcanic rocks are characterized by high ε<sub>Nd(T)</sub> values (+2.79 to +5.89) and low initial <sup>87</sup>Sr/<sup>86</sup>Sr ratios (0.7032–0.7054). The assimilation–fractional crystallization (AFC) model is used to explain the isotope characteristics
of the Late Devonian volcanic rocks in the southwestern Tianshan Mountains. Calculation shows that the Late Devonian samples
could be formed by the AFC process between depleted mantle and continental crust. The Carboniferous basaltic rocks originated
by partial melting of the mantle wedge.
</p>