Petrogenesis of Pyroclastic Deposits of the Vulsini VolcanicCenter, Italy

意大利武尔西尼火山中心火山碎屑矿床的岩石成因

• 批准号: 8720595
• 负责人: Daniel Barker
• 金额: $ 0.98万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-03-01 至 1989-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8720595&HistoricalAwards=false
• 关键词: Petrogenesis; Pyroclastic; Deposits; Vulsini; VolcanicCenter

In the Vulsini Volcanic complex in central Italy, mafic and felsic magmas have erupted with varying degrees of mixing. Despite the predominance of tephra in the Vulsini area, models of magmatic evolution at this center have been based almost entirely upon compositional variations among lava flows, and such sampling cannot avoid bias. Pumice clasts in tephra provide more representative samples of move voluminous magmas at the instant of eruptive fragmentation, and more adequately reflect the petrogenetically significant crustal components that are likely to be greatly undersampled if felsic tephra are ignored. This is an ongoing effort whose aim is to provide a petrogenetic model based on microprobe, major and trace element and isotopic analyses of crystals and glasses in an extensive suite of fresh pumice clasts from carefully studied pyroclastic units. This award is specifically to provide 60 neutron activation analyses. The results should advance understanding of the genesis of subsequent evolution of the mafic silica-undersaturated potassic magmas and the silica-oversaturated magmas, the processes by which the two magma types mixed, and the mechanisms of eruption of the resulting broad compositional range of magmas.

在意大利中部的武尔西尼火山群中，镁铁质和长英质岩浆以不同程度的混合喷发。 尽管武尔西尼地区以火山灰为主，但该中心的岩浆演化模型几乎完全基于熔岩流的成分变化，这种采样无法避免偏差。 火山灰中的浮石碎屑提供了在喷发碎裂瞬间移动的大量岩浆的更具代表性的样本，并且更充分地反映了具有岩石成因的重要地壳成分，如果忽略长英质火山灰，这些成分可能会被严重采样不足。 这是一项持续的工作，其目的是提供基于微探针、主量元素和微量元素以及对来自仔细研究的火山碎屑单元的大量新鲜浮石碎屑中晶体和玻璃的同位素分析的岩石成因模型。 该奖项专门提供 60 个中子活化分析。 研究结果应有助于促进对镁铁质硅质不饱和钾质岩浆和硅质过饱和岩浆后续演化的成因、两种岩浆类型混合的过程以及由此产生的广泛岩浆成分范围的喷发机制的理解。