Volcanological and petrological evolution of Vulcano island (Aeolian Arc, southern Tyrrhenian Sea)
Volcanological and petrological evolution of Vulcano island (Aeolian Arc, southern Tyrrhenian Sea)
复制标题
武尔卡诺岛（伊奥利亚弧，第勒尼安海南部）的火山学和岩石学演化
DOI：
--
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
L. Civetta
中科院分区：
文献类型：
--
作者：
G. Astis;L. Volpe;A. Peccerillo;L. Civetta
报道了火山岩的岩石学和地球化学数据。陆上火山作用（120万年到现在）建立了一个NW-SE细长的复合结构，受两个相交的多级破火山口。年龄大于20 ka的火山岩主要由高钾钙碱性（HKCA）到钾玄质（SHO）镁铁质岩石组成。这些岩浆与大陆地壳发生了显著的相互作用，产生了可变的Sr同位素比值（0.70412 - 0.70520）。然而，一个主要的作用也发挥了输入到岩浆房，这阻止了岩浆的进一步演化的母液。HKCA，SHO，钾质（KS）岩石形成于20至8万年，显示出更大范围的SiO2（从钾玄岩到流纹岩）和更高浓度的不相容元素相对于前一阶段。Sr同位素比值变化不大（0.70448 - 0.70486）。该阶段主要的演化过程是碳酸盐和镁铁质液体的混合和分步结晶过程。年龄小于8ka的火山岩主要由SHO和含白榴石的KS基性岩石组成，并有丰富的中间产物和次生产物。镁铁质岩和中性岩的不相容元素丰度和Sr同位素比值与前一阶段火山岩相似，但某些流纹岩中的87Sr/86Sr比值较高（0.70494 - 0.70583）。这些产物起源于FC、地壳同化和岩浆混合过程的复杂相互作用。大多数镁铁质岩石表现出增加不相容元素丰度，Rb/Sr，Rb/Ba，Mg/Al，Mg/Ca，和减少大离子亲石高场强元素的比例，通过从老HKCA-SHO年轻SHO-KS火山岩。这些变化表明，岩浆源从轻微交代软流圈（肥沃的橄榄岩）更强烈的交代岩石圈地幔（残留橄榄岩）。与时间相关的岩石学和地球化学变化已被用来开发一个模型的演变Vulcano管道系统。
Petrological and geochemical data are reported for volcanic rocks from Vulcano island. The subaerial volcanism (120 ka to present) built up a NW-SE elongated composite structure, affected by two intersecting multistage calderas. Volcanics older than 20 ka consist mostly of high-K calc-alkaline (HKCA) to shoshonitic (SHO) mafic rocks. These magmas interacted significantly with the continental crust, which generated variable Sr isotopic ratios (0.70412–0.70520). However, a major role was also played by input of parental liquids into the magma chamber, which prevented further evolution of the magmas. HKCA, SHO, and potassic (KS) rocks formed from 20 to 8 ka, display a much larger range of SiO2 (from shoshonites to rhyolites) and higher concentrations of incompatible elements with respect to the previous stage. Sr isotopic ratios show small variations (0.70448–0.70486). Mixing of silicic and mafic liquids and fractional crystallization processes (FC) were the main evolutionary processes during this stage. Volcanics younger than 8 ka consist of SHO and leucite-bearing KS mafic rocks, with abundant intermediate and silicic products. Mafic and intermediate rocks display similar incompatible element abundances and Sr isotopic ratios as the previous stage volcanics, whereas higher 87Sr/86Sr (0.70494–0.70583) are observed in some rhyolites. These products originated from a complex interplay of FC, crustal assimilation, and magma mixing processes. The most mafic rocks show increasing incompatible element abundances, Rb/Sr, Rb/Ba, Mg/Al, Mg/Ca, and a decrease in large ion lithophile to high field strength element ratios, passing from older HKCA-SHO to the younger SHO-KS volcanics. These variations suggest a shifting of magma sources from a slightly metasomatized asthenosphere (fertile peridotite) to a more strongly metasomatized lithospheric mantle (residual peridotite). Time-related petrological and geochemical variations have been used to develop a model for the evolution of the Vulcano plumbing system.