Geochemical features and geodynamic significance of the southern Tyrrhenian backarc basin
Geochemical features and geodynamic significance of the southern Tyrrhenian backarc basin
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第勒尼安弧后盆地南部地球化学特征及地球动力学意义
DOI：
10.1130/2007.2418(11
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发表时间：
2007
影响因子：
--
通讯作者：
M. Marani
中科院分区：
文献类型：
--
作者：
T. Trua;G. Serri;M. Marani
第勒尼安南部地区是岛弧玄武岩（IAB）型和洋岛玄武岩（OIB）型岩浆共存的罕见活动弧后盆地。 IAB 型岩浆活动最为常见，而 OIB 型岩浆仅限于少数地区。本文总结了南第勒尼安海底火山样本的地球化学和同位素特征，特别关注最近海底采样期间回收的样本。来自第勒尼安海最大海山马西里火山的样品，以及普罗米泰奥海底熔岩场和帕利努罗海山的样品，全面展示了第勒尼安海南部岩浆作用的地幔来源。这些样品大多数是相对高镁的玄武岩，与原生岩浆成分相近，从而深入了解该地区 IAB 型和 OIB 型岩浆的岩石成因。岩石学数据与新的测深数据相结合，可以重建第勒尼安弧后盆地南部的地球动力学演化。我们认为，第勒尼安弧后盆地南部记录的从 IAB 型岩浆到 OIB 型岩浆的转变与软流圈地幔从非洲下方围绕爱奥尼亚板片边缘的传播有关。数据表明，自第勒尼安南部地区新近纪早期演化以来，来自非洲下方的软流圈流入一直很重要。
The southern Tyrrhenian region represents a rare case of an active backarc basin where island-arc basalt (IAB)–type and ocean-island basalt (OIB)–type magmas coexist. IAB-type magmatism is the most common, whereas OIB-type magmas are restricted to a few areas. Geochemical and isotopic characteristics of southern Tyrrhenian submarine volcanic samples are summarized herein, with special attention to samples recovered during recent seafl oor sampling. Samples derived from Marsili volcano, the biggest seamount in the Tyrrhenian Sea, together with those of the Prometeo submarine lava fi eld and Palinuro seamount, give a comprehensive picture of the mantle sources of southern Tyrrhenian magmatism. Most of these samples are relatively high-magnesian basalts that approximate primary magma compositions, thus providing insight into petrogenesis of IABand OIB-type magmas of this area. Petrological data, integrated with new bathymetric data, allow the geodynamic evolution of the southern Tyrrhenian backarc basin to be reconstructed. We suggest that the transition from IABto OIB-type magmas recorded in the southern Tyrrhenian backarc basin is related to the propagation of asthenospheric mantle from beneath Africa around the edges of the Ionian slab. The data suggest that the infl ow of asthenosphere from beneath Africa has been important since the early Neogene evolution of the southern Tyrrhenian region.