Diffusion profiles in olivine crystals from the final mafic eruption products of the compositionally zoned Laacher See tephra deposit were measured to identify recharge and eruption-triggering events prior to the eruption of the Laacher See volcano (12.9 kyr). These products represent the hybrids of mixing between phonolite and intruding basanite at the bottom of the reservoir, which is likely related to the eruption-triggering event. Additionally, olivine crystals from ten basanitic scoria cones and maar deposits (East Eifel) and two nephelinites (West Eifel) were analyzed to constrain histories of olivine in Quaternary basanite magmas. Olivine crystals from the Laacher See hybrids vary in core composition (Fo83–89) and show reversely zoned mantles with high Fo87.8–89 compared to olivine in East Eifel basanites erupted in nearby, older scoria cones. Towards the crystal margin, olivine in the hybrids develop a normally zoned overgrowth (Fo86.5–87.5). Olivine from East Eifel basanites show similar zonation and core compositions (Fo80–88) but have less forsteritic mantles (Fo83–88) indicating that these basanites are less primitive than those recharging the Laacher See reservoir (> Fo89). Olivine in the West Eifel nephelinites show mantles similar to those from Laacher See (Fo87.5–90), but have normal zoning and high-Fo cores (Fo88–92). This indicates that olivine in the Laacher See hybrids were entrained by a near-primary basanite from older cumulates just before hybridization of the basanite with the phonolite. Diffusion modeling indicates maximum timescales between entrainment and eruption of Laacher See of 30–400 days that are comparable to those calculated for olivine from basanitic scoria cones (10–400 days).

中文翻译：

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德国西部埃菲尔火山区从岩浆混合到碱性火山喷发的时间尺度

在 Laacher See 火山 (12.9 kyr) 喷发之前，对成分分区 Laacher See tephra 矿床的最终镁铁质喷发产物的橄榄石晶体中的扩散剖面进行了测量，以确定补给和喷发触发事件。这些产物代表了在储层底部的响岩和侵入的玄武岩之间的混合体，这很可能与触发喷发事件有关。此外，分析了来自十个玄武岩矿渣锥体和玛珥矿床（东埃菲尔）和两个霞石（西埃菲尔）的橄榄石晶体，以限制第四纪玄武岩岩浆中橄榄石的历史。来自 Laacher See 杂种的橄榄石晶体在核心成分 (Fo83-89) 上有所不同，与附近喷发的东埃菲尔 basanites 中的橄榄石相比，显示出具有高 Fo87.8-89 的反向分区地幔，较旧的熔渣锥。在晶体边缘，杂种中的橄榄石发展出正常分区的过度生长（Fo86.5-87.5）。来自东埃菲尔玄武岩的橄榄石显示出类似的分带和核心成分 (Fo80-88)，但具有较少的镁橄榄石地幔 (Fo83-88)，表明这些玄武岩不如为 Laacher See 水库补给的那些 (> Fo89) 原始。West Eifel 霞石中的橄榄石显示出类似于 Laacher See (Fo87.5-90) 的地幔，但具有正常的分带和高 Fo 核 (Fo88-92)。这表明 Laacher See 杂种中的橄榄石在 basanite 与 phonolite 杂交之前被来自较老堆积物的近原生 basanite 夹带。