DOI: 10.1007/s00531-015-1195-x
Scopus记录号: 2-s2.0-84930149767
论文题名: Reconstructing subduction polarity through the geochemistry of mafic rocks in a Cambrian magmatic arc along the Gondwana margin (Órdenes Complex, NW Iberian Massif)
作者: Andonaegui P. ; Sánchez-Martínez S. ; Castiñeiras P. ; Abati J. ; Arenas R.
刊名: International Journal of Earth Sciences
ISSN: 14373254
出版年: 2016
卷: 105, 期: 3 起始页码: 713
结束页码: 725
语种: 英语
英文关键词: Gabbronorites
; NW Iberia
; Peri-Gondwanan Cambrian arc
; Sr and Sm–Nd isotopic geochemistry
; Subduction polarity
; Órdenes Complex
Scopus关键词: Cambrian
; Gondwana
; igneous geochemistry
; mafic rock
; samarium
; strontium isotope
; subduction
; tectonic reconstruction
; Iberian Massif
英文摘要: In the allochthonous complexes of the NW Iberian Massif, the Upper Units have been interpreted as a section of a peri-Gondwanan magmatic arc active from Middle Cambrian to Early Ordovician times. The main plutonic bodies intruding the arc metasediments are the Monte Castelo gabbronorites and the Corredoiras orthogneisses, which include minor metagabbronorite bodies, both dated at ca 500 Ma. The geochemical features of Monte Castelo metagabbronorites indicate a tholeiitic affinity, with negative Nb anomaly; its 143Nd/144Nd ratios are high (0.5143119–0.513019), whereas initial 87Sr/86Sr ratios are low (0.702562–0.703174), with positive εNdi values (+7.8 to +5.4). The geochemistry of Corredoiras metagabbronorites indicates a calc-alkaline affinity, also with negative Nb anomaly, low 143Nd/144Nd (0.512575–0.512436) and high initial 87Sr/86Sr (0.705082–0.706684), εNdi values ranging between −0.65 and +1.83. In the εNd versus age diagram, Monte Castelo samples show compositions equivalent to the contemporaneous depleted mantle. Corredoiras metagabbros have much lower εNdi values compared with Monte Castelo samples, with older model ages ranging between 1165 and 1291 Ma, suggesting contamination of the original mafic mantle-derived magmas with an older continental crust. These geochemical features can be linked to the setting of a mature volcanic arc, in which Monte Castelo metagabbros were located close to the trench, while Corredoiras metagabbros would be in a relatively distant position from the trench, thus indicating subduction polarity. © 2015, Springer-Verlag Berlin Heidelberg. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84930149767&doi=10.1007%2fs00531-015-1195-x&partnerID=40&md5=7ebedbead227ccaad7b8db9e3429918c
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70172
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Dpto. Petrología y Geoquímica (UCM), Universidad Complutense de Madrid, Madrid, Spain; Instituto de Geociencias (UCM, IGEO), Universidad Complutense de Madrid, Madrid, Spain
Recommended Citation:
Andonaegui P.,Sánchez-Martínez S.,Castiñeiras P.,et al. Reconstructing subduction polarity through the geochemistry of mafic rocks in a Cambrian magmatic arc along the Gondwana margin (Órdenes Complex, NW Iberian Massif)[J]. International Journal of Earth Sciences,2016-01-01,105(3)