Geochronology and petrogenesis of hornblende-bearing basalts (Rhön, Germany) - remnants of volcanic rocks from the lithospheric upper mantle)

含角闪石玄武岩的地质年代学和岩石成因（德国罗恩）——岩石圈上地幔火山岩的残余物）

• 批准号: 106887825
• 负责人: Professor Dr. Stefan Jung
• 金额: --
• 依托单位: Mineralogisch-Petrographisches Institut (MPI)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/106887825?language=en
• 关键词: Geochronology; petrogenesis; hornblende; bearing; basalts

The proposed project deals with the geochronology, geochemistry and isotope composition of alkali olivine basalts s. /. that represent a significant part of the volcanic rocks in the Rhön area (Germany). In contrast to other volcanic occurrences in central Europe, most of these alkaline volcanic rocks contain mm- to cm-sized hornblende phenocrysts beside clinopyroxene (some with green cores) and olivine. Based on these unusual mineralogical composition and some geochemical features, i.e. high TiO2 contents > 3.0 wt%, it can be suggested that the hornblendebearing basalts originate from sources distinct to those envisaged for other alkaline rocks from central Europe, i.e. probably representing melts of the subcrustal lithospheric mantle. The volcanic rocks will be investigated for Nd, Sr, Pb, Hf, Os and O whole rock isotopes and the major and trace element composition of the hornblende phenocrysts will be determined by using an electron microprobe and an ionprobe. Ar-Ar age determinations on hornblende phenocrysts will complement the isotope data. In addition, it is planned to analyse the hornblende phenocrysts for Nd, Sr, Pb and O isotopes. Results obtained during this study will place constraints on possible heterogeneities of the upper mantle in rift-related areas and can also be used to distinguish second order processes (crustal contamination with or without fractional crystallization, magma mixing) from first order processes (partial melting of spinel or garnet peridotite with or without OH-bearing minerals etc.). The project is therefore ideally suited to add knowledge on lithosphere dynamics in rift-related continental setting.

建议的项目涉及碱性橄榄玄武岩的年代学、地球化学和同位素组成。/.这些岩石代表了Rhön地区（德国）火山岩的重要组成部分。与欧洲中部的其他火山岩不同，这些碱性火山岩中的大多数除了单斜辉石（有些具有绿色核）和橄榄石外，还含有毫米至厘米大小的角闪石斑晶。基于这些不寻常的矿物学成分和某些地球化学特征，即高TiO 2含量> 3.0 wt%，可以认为含角闪石玄武岩的来源与中欧其他碱性岩石的来源不同，即可能代表地壳下岩石圈地幔的熔体。用电子探针和离子探针对火山岩进行了Nd、Sr、Pb、Hf、Os和O全岩同位素研究，并测定了角闪石斑晶的主量和微量元素组成。角闪石斑晶的Ar-Ar年龄测定将补充同位素数据。此外，计划对角闪石斑晶进行Nd、Sr、Pb和O同位素分析。在这项研究中获得的结果将限制可能的不均匀性的上地幔裂谷相关的地区，也可以用来区分第二级过程（地壳污染或不分离结晶，岩浆混合）从第一级过程（部分熔融的尖晶石或石榴石橄榄岩或含OH的矿物等）。因此，该项目非常适合于增加有关大陆裂谷背景下岩石圈动力学的知识。

项目成果

Amphibole in alkaline basalts from intraplate settings: implications for the petrogenesis of alkaline lavas from the metasomatised lithospheric mantle

• DOI: 10.1007/s00410-014-0989-3
• 发表时间: 2014-03
• 期刊: Contributions to Mineralogy and Petrology
• 影响因子: 3.5
• 作者: Bernhard Mayer;Bernhard Mayer;Stefan Jung;Rolf L. Romer;J. Pfänder;A. Klügel;Andreas Pack;E. Gröner

Petrogenesis of Tertiary Hornblende-bearing Lavas in the Rhön, Germany

德国罗恩河第三纪含角闪石熔岩的岩石成因

• DOI: 10.1093/petrology/egt042
• 发表时间: 2013
• 期刊: Journal of Petrology
• 影响因子: 3.9
• 作者: Stracke;Garbe-Schönberg
• 通讯作者: Garbe-Schönberg