Melts of sediments in the mantle wedge of the Oman ophiolite
Melts of sediments in the mantle wedge of the Oman ophiolite
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DOI：
10.1130/g36451.1
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发表时间：
2015-04
期刊：
影响因子：
5.8
通讯作者：
K. Haase;S. Freund;J. Koepke;F. Hauff;M. Erdmann
中科院分区：
文献类型：
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作者：
K. Haase;S. Freund;J. Koepke;F. Hauff;M. Erdmann
阿曼蛇绿岩的地壳部分的岩石表现出越来越多的输入的俯冲分量随时间的推移，最有可能反映了俯冲板片以上的蛇绿岩的代。领域的关系，新的地球化学数据和Nd-Hf同位素数据的长英质镁铁质侵入岩在地幔Haylayn块在阿曼蛇绿岩harzburtenes建议在地幔楔的晚岩浆事件前不久的蛇绿岩仰冲。不相容元素含量和低的eNd和eHf的长英质岩石排除镁铁质岩浆的分化，但与部分熔融的远洋沉积物类似于大陆碰撞带的浅色花岗岩的起源是一致的。这些熔体显然与镁铁质岩浆混合，类似于蛇绿岩中富集的晚期熔岩。浅色花岗岩侵入地幔楔证实了俯冲带沉积物熔体从俯冲板块向地幔的转移。我们认为，富集Rb，K，和Pb观察到的阿曼玻安岩是由添加熔融的沉积物类似于那些从Haylayn块玻安岩源在地幔楔。
The rocks in the crustal section of the Oman ophiolite show an increasing input of a subduction component with time, most likely reflecting the generation of the ophiolite above a subducting slab. Field relations, new geochemical data, and Nd-Hf isotope data for felsic to mafic intrusive rocks in the mantle harzburgite from the Haylayn block in the Oman ophiolite suggest late magmatic events in a mantle wedge shortly before obduction of the ophiolite. Incompatible element contents and low eNd and eHf of the felsic rocks exclude differentiation from mafic magmas, but are consistent with an origin by partial melting of pelagic sediments similar to leucogranites in continental collision zones. These melts apparently mixed with mafic magmas resembling enriched late-stage lavas from the ophiolite. The leucogranitic intrusions into the mantle wedge confirm the transfer of melts of sediments from the subducted plate into the mantle at subduction zones. We suggest that the enrichment of Rb, K, and Pb observed in the Oman boninites is caused by addition of melts of sediments similar to those from the Haylayn block to the boninite source in the mantle wedge.