Using chalcophile elements to constrain crustal contamination and xenolith-magma interaction in Cenozoic basalts of eastern China
Using chalcophile elements to constrain crustal contamination and xenolith-magma interaction in Cenozoic basalts of eastern China
复制标题
利用亲铜元素抑制中国东部新生代玄武岩中的地壳污染和捕虏岩-岩浆相互作用
DOI：
10.1016/j.lithos.2016.04.032
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发表时间：
2016-08
期刊：
影响因子：
3.5
通讯作者：
Xu Xi-Sheng
中科院分区：
文献类型：
--
作者：
Zeng Gang;Huang Xiao-Wen;Zhou Mei-Fu;Chen Li-Hui;Xu Xi-Sheng
大陆玄武岩具有复杂的成岩过程，其化学成分受多阶段地质演化的影响。与亲石元素相比，Ni、铂族元素（PGEs）和Cu等亲硫元素在幔源岩浆演化过程中对硫化物分凝和分离结晶作用敏感，对大陆玄武岩的成因具有制约作用。南京玄武岩区新生代陆内碱性玄武岩包括高钙和低钙两种类型。这些玄武岩的PGE含量较低，Ir含量在0.016 ~ 0.288 ppb之间，Cu/Pd比值较高，在0.7 × 105 ~ 4.7 × 105之间（DMM为5.7 × 103），表明它们可能来自硫化物饱和的地幔源区，熔融过程中残留了不同量的硫化物，或者可能经历了早期的地幔硫化物分凝作用。相对较高的Cu/Pd比值沿着与高钯浓度的高钙碱性玄武岩表明，在岩浆上升过程中的硫化物的额外的去除。由于这些玄武岩具有较高的Pd/Ir比值（2.8-16.8）和较低的Ce/Pb比值（9.9-19.7）以及ε Nd值（+3.6-+6.4），地壳混染可能是导致硫化物饱和和迁移的一个潜在过程。一些高钙玄武岩的Pd/Ir比值的显着增加可以解释为分馏的月桂石或Ru-Os-Ir合金与橄榄石或铬铁矿。低钙碱性玄武岩的PGE含量与MgO、Sc含量、不相容元素比值（Lu/Hf、Na/Ti和Ca/Al）和Hf同位素具有良好的相关性。Pd/Ir（或Rh/Ir）和Na/Ti（或Ca/Al）比之间也观察到良好的相关性。这些元素的比例和Hf同位素的变化是以前记录的橄榄岩捕虏体释放的熔体在上升过程中的混合诱导。因此，我们认为，这种捕虏体-岩浆相互作用也负责的低钙碱性玄武岩的可变PGE组成。
Continental basalts have complicated petrogenetic processes, and their chemical compositions can be affected by multi-staged geological evolution. Compared to lithophile elements, chalcophile elements including Ni, platinum-group elements (PGEs) and Cu are sensitive to sulfide segregation and fractional crystallization during the evolution of mantle-derived magmas and can provide constraints on the genesis of continental basalts. Cenozoic intra-continental alkaline basalts in the Nanjing basaltic field, eastern China, include high-Ca and low-Ca varieties. All these basalts have poor PGE contents with Ir ranging from 0.016 ppb to 0.288 ppb and high Cu/Pd ratios from 0.7 × 105to 4.7 × 105(5.7 × 103for DMM), indicating that they were derived from sulfide-saturated mantle sources with variable amounts of residual sulfide during melting or might undergo an early-sulfide segregation in the mantle. Relatively high Cu/Pd ratios along with high Pd concentrations for the high-Ca alkaline basalts indicate an additional removal of sulfide during magma ascent. Because these basalts have high, variable Pd/Ir ratios (2.8–16.8) with low Ce/Pb (9.9–19.7) ratios and εNdvalues (+ 3.6–+6.4), crustal contamination is proposed to be a potential process to induce the sulfide saturation and removal. Significantly increased Pd/Ir ratios for few high-Ca basalts can be explained by the fractionation of laurite or Ru-Os-Ir alloys with olivine or chromite. For low-Ca alkaline basalts, their PGE contents are well correlated with the MgO, Sc contents, incompatible element ratios (Lu/Hf, Na/Ti and Ca/Al) and Hf isotopes. Good correlations are also observed between Pd/Ir (or Rh/Ir) and Na/Ti (or Ca/Al) ratios. Variations of these elemental ratios and Hf isotopes is previously documented to be induced by the mixing of peridotite xenolith-released melts during ascent. Therefore, we suggest that such xenolith–magma interaction are also responsible for the variable PGE compositions of low-Ca alkaline basalts.
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影响因子：
3.9
作者：
S. Klemme;D. Günther;K. Hametner;Stefan Prowatke;T. Zack
通讯作者：
S. Klemme;D. Günther;K. Hametner;Stefan Prowatke;T. Zack
DOI：
10.30965/9783846743737_017
发表时间：
2007
期刊：
--
影响因子：
--
作者：
I. A. J. Maccarthy
通讯作者：
I. A. J. Maccarthy
影响因子：
5
作者：
M. Rehkämper;A. Halliday;J. Fitton;Der-Chuen Lee;M. Wieneke;N. Arndt
通讯作者：
M. Rehkämper;A. Halliday;J. Fitton;Der-Chuen Lee;M. Wieneke;N. Arndt
影响因子：
5
作者：
K. Righter;A. Campbell;M. Humayun;R. Hervig
通讯作者：
K. Righter;A. Campbell;M. Humayun;R. Hervig
影响因子：
4.8
作者：
R. Keays;P. Lightfoot
通讯作者：
R. Keays;P. Lightfoot