Sulfide saturation in alkaline to peralkaline igneous rocks.

碱性至过碱性火成岩中的硫化物饱和度。

• 批准号: 271894046
• 负责人: Privatdozent Dr. Michael Marks
• 金额: --
• 依托单位: Arbeitsgruppe Geologie und Geodynamik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/271894046?language=en
• 关键词: Sulfide; saturation; alkaline; peralkaline; igneous

The behavior of sulfur in silicate melts is a widely discussed topic: Its release during volcanic eruptions affects the global climate, and the sulfur content of magmas exerts a major control on the genesis of magmatic to hydrothermal ore deposits. Primary sulfides (mainly pyrrhotite, chalcopyrite and molybdenite) and other sulfur-bearing minerals (mainly apatite and sodalite group minerals) in mafic, intermediate and granitic systems have been the focus of many recent studies, but no detailed and systematic study on this topic in alkaline to peralkaline magmatic systems has been undertaken so far.The present proposal investigates and compares the primary sulfide inventory of two otherwise well-characterized alkaline to peralkaline plutonic complexes (Tamazeght in Morocco and Ilimaussaq in Greenland) and their spatially associated and genetically related dyke rocks. The rocks to be investigated cover a large compositional diversity ranging mainly from gabbroic (alkali basaltic) via monzonitic (latitic) and syenitic (trachytic) to nepheline syenitic (phonolitic) compositions. Therefore, the results of this study will have general implications for the behavior of sulfur in alkaline to peralkaline magmatic systems. The various sulfides will be analyzed for their major, minor and trace element composition and their sulfur isotopic composition in order to track their compositional evolution during magmatic differentiation. These data will be combined with determination of sulfur concentrations in other sulfur-bearing minerals (apatite and sodalite) and with compositional data on co-existing Fe-Mg silicates and Fe-Ti oxides, since this provides important constraints on prevailing oxygen and sulfur fugacity during their formation. The sulfur isotope composition of the sulfides will provide constraints on the sulfur isotope composition of the magmas and the temperature of crystallization of the different sulfide assemblages.The variability within and between the two complexes is expected to reveal detailed insights into magma chamber processes (e.g., sulfide-silicate melt separation, fractional crystallization, magma recharge, formation of magmatic layering) and will decipher the influence of sulfide formation on the geochemical evolution of alkaline to peralkaline magmas with possible implications for the ore potential of such systems. The comparison between plutonic rocks and dyke rocks will provide detailed insight into potential differences with respect to the retention and alteration of the primary chemical and isotopic compositions of sulfides related to different cooling rates and the intensity of hydrothermal overprint.

硅酸盐熔体中硫的行为是一个广泛讨论的话题：火山喷发期间硫的释放影响全球气候，岩浆中的硫含量对岩浆到热液矿床的成因起着主要控制作用。镁铁质、中间质和花岗质体系中的原生硫化物（主要是磁黄铁矿、黄铜矿和辉钼矿）和其他含硫矿物（主要是磷灰石和方钠石族矿物）一直是近年来许多研究的焦点，但目前尚未对此主题进行详细和系统的研究。到目前为止，已经进行了碱性到过碱性岩浆系统的研究。本提案调查并比较了两个其他已充分表征的碱性到过碱性岩浆系统的原生硫化物库存深成杂岩体（摩洛哥的塔马泽特和格陵兰岛的伊利毛萨克）及其空间相关和成因相关的岩脉岩。待研究的岩石具有很大的成分多样性，主要包括从辉长岩（碱玄武岩）到二长岩（晶质岩）和正长岩（粗面岩）到霞石正长岩（声石质）成分。因此，这项研究的结果将对碱性至过碱性岩浆系统中硫的行为具有一般意义。将分析各种硫化物的主量、微量和微量元素组成及其硫同位素组成，以跟踪其在岩浆分异过程中的成分演化。这些数据将与其他含硫矿物（磷灰石和方钠石）中硫浓度的测定以及共存的铁镁硅酸盐和铁钛氧化物的成分数据相结合，因为这对普遍的氧和硫逸度提供了重要限制在他们的形成过程中。硫化物的硫同位素组成将对岩浆的硫同位素组成和不同硫化物组合的结晶温度提供限制。两种复合体内部和之间的变化预计将揭示对岩浆室过程的详细了解（例如，硫化物-硅酸盐熔体分离、分异结晶、岩浆补给、岩浆层的形成），并将破译硫化物形成对地球化学演化的影响碱性岩浆到过碱性岩浆的变化可能对此类系统的矿石潜力产生影响。深成岩和岩脉岩之间的比较将详细了解与不同冷却速率和热液叠印强度相关的硫化物主要化学和同位素组成的保留和变化方面的潜在差异。

项目成果

Sulfides in alkaline and peralkaline rocks: textural appearance and compositional variations

碱性和过碱性岩石中的硫化物：结构外观和成分变化

• DOI: 10.1127/njma/2018/0095
• 发表时间: 2018
• 期刊: Neues Jahrbuch für Mineralogie - Abhandlungen
• 作者: Babiel; R.; Marks; M.A.W.; Neumann; U.; Markl; G.
• 通讯作者: G.

Sulphur isotopes of alkaline magmas unlock long-term records of crustal recycling on Earth

碱性岩浆的硫同位素揭示了地球上地壳循环的长期记录

• DOI: 10.1038/s41467-019-12218-1
• 发表时间: 2019-09-16
• 期刊: Nature Communications
• 影响因子: 16.6
• 作者: W. Hutchison;Rainer J. Babiel;A. Finch;M. Marks;G. Markl;A. Boyce;E. Stüeken;H. Friis;A. Borst;N. Horsburgh
• 通讯作者: N. Horsburgh