Integrated field, satellite and petrological observations of the November 2010 eruption of Erta Ale
Integrated field, satellite and petrological observations of the November 2010 eruption of Erta Ale
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DOI：
10.1007/s00445-012-0660-7
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发表时间：
2012-12-01
影响因子：
3.5
通讯作者：
Saunders, Kate
中科院分区：
文献类型：
--
作者：
Field, Lorraine;Barnie, Talfan;Saunders, Kate
埃塞俄比亚的埃尔塔阿莱火山于2010年11月喷发，在主火山口底部形成了新的熔岩流，这是自1973年以来第一次从南坑喷发到主火山口，也是现代卫星时代以来这座偏远火山的第一次喷发。几十年来，Erta Ale一直包含一个持续活跃的熔岩湖，通常被限制在主火山口下方几十米的南部坑内。我们将地面实地观测与SEVIRI卫星的多光谱成像相结合，重建了从2010年11月11日开始到12月14日之前结束的整个喷发事件。11月14日至19日期间出现了一段平静期。主要喷发活动在11月19日至22日之间发展，最终在12月8日至15日之间减弱到喷发前的水平。估计熔岩喷发的总体积约为0.006公里(3)。2010年熔岩的矿物学为斜长石+斜辉石+橄榄石。从地球化学的角度来看，这些熔岩比以前喷发的熔岩更具基性，但位于Erta Ale的历史熔岩范围内。SIMS对含有橄榄石的熔体包裹体的分析表明，Erta Ale熔岩的挥发物相对较少，H2O含量为1300 ppm， CO2含量为200 ppm。然而，熔体包裹体的微量元素和挥发性元素不相容的系统分析表明，2010年11月的熔岩是挥发性饱和的，脱气和结晶同时发生。挥发饱和压力在7 ~ 42 MPa之间，表明结晶较浅。根据矿物/液体温度计计算出的喷发前和熔体包裹体的温度接近1150摄氏度，与之前公布的现场测量结果一致。
Erta Ale volcano, Ethiopia, erupted in November 2010, emplacing new lava flows on the main crater floor, the first such eruption from the southern pit into the main crater since 1973, and the first eruption at this remote volcano in the modern satellite age. For many decades, Erta Ale has contained a persistently active lava lake which is ordinarily confined, several tens of metres below the level of the main crater, within the southern pit. We combine on-the-ground field observations with multispectral imaging from the SEVIRI satellite to reconstruct the entire eruptive episode beginning on 11 November and ending prior to 14 December 2010. A period of quiescence occurred between 14 and 19 November. The main eruptive activity developed between 19 and 22 November, finally subsiding to pre-eruptive levels between 8 and 15 December. The estimated total volume of lava erupted is similar to 0.006 km(3). The mineralogy of the 2010 lava is plagioclase + clinopyroxene + olivine. Geochemically, the lava is slightly more mafic than previously erupted lava lining the caldera floor, but lies within the range of historical lavas from Erta Ale. SIMS analysis of olivine-hosted melt inclusions shows the Erta Ale lavas to be relatively volatile-poor, with H2O contents a parts per thousand currency sign1,300 ppm and CO2 contents of a parts per thousand currency sign200 ppm. Incompatible trace and volatile element systematics of melt inclusions show, however, that the November 2010 lavas were volatile-saturated, and that degassing and crystallisation occurred concomitantly. Volatile saturation pressures are in the range 7-42 MPa, indicating shallow crystallisation. Calculated pre-eruption and melt inclusion entrapment temperatures from mineral/liquid thermometers are similar to 1,150 A degrees C, consistent with previously published field measurements.