G字头课程《Ore-forming Mineralogy（成矿矿物学）》开课通知

应中国地质大学（武汉）资源学院李建威教授邀请，德国地学研究中心Daniel Harlov教授于3月18日至4月13日访问我校。期间，Daniel Harlov将开设研究生公选课G020002《Ore-forming Mineralogy（成矿矿物学）》。课程将围绕成矿相关的磷酸盐、硅酸盐、氧化物和硫化物等矿物的研究，从矿物角度探讨矿床成因以及演化过程。该课程对矿物学岩石学矿床学、资源普查与勘探、地质工程等专业的学生开放。开课时间为2018年3月29日-4月7日，每日10:05-11:40，具体信息详见下表。该课程提供1个通选课学分。欢迎对成矿矿物学研究有兴趣的各专业学生选课或前来旁听！选课时间为3月23日00:00-4月7日00:00，请广大研究生积极参与，选课不需改变培养计划，请选择方案外课程进行选课。

任课教师简介：

丹尼尔.哈洛夫，德国地学研究中心中心高级研究员，约翰内斯堡大学访问教授，中国地质大学（武汉）地大学者“学科首席教授（短期）”，同时是美国矿物家学会理事。主要研究方向涉及实验岩石学、矿物学、热化学模拟和岩石学等，主要研究课题包括地壳中流体在变质过程中的作用，不同P-T范围内矿物相平衡实验，矿物-流体交互反应，热动力学模拟，岩浆过程中水的作用，矿物合成和矿物特征，铁氧化物磷灰石IOA和REE矿床等。现在为American Mineralogist副主编、Lithos副主编，并合作编辑多卷特约主题文章以及两本专著，以第一作者在Elements, EG, JP, CMP, CG, GCA等地学期刊发表论文50余篇。

授课时间及地点：

Ore-forming mineralogy课程详细介绍：

Lecture 1:  Metasomatic alteration of apatite: fluid infiltration and fluid-aided formation of monazite, xenotime, and other mineral inclusions.

Description:  Apatite is a superb mineral by which to investigate the nature of fluids that have passed through and altered a rock (metasomatic processes). It

can be chemically altered by aqueous brines (NaCl–KCl–CaCl₂–H₂O), pure H₂O, and aqueous fluids containing CO₂, HCl, H₂SO₄, and/or F. Thus, apatite is the perfect tracker of metasomatic fluids, providing information on the timing and duration of metasomatism, the temperature of the fluids, and the composition of the fluids, all of which can feed back into the history of the host rock itself.

Lecture 2:  Metasomatic alteration of monazite: actinide mobility and timing fluid-rock interaction.

Description: Monazite [(Ce,LREE,Th,U,Ca)(P,Si)O₄] is major sink for Th, U,  and LREE in metamorphic and igneous rocks mostly as an accessory mineral, and as both an accessory and major mineral in ore deposits.  Monazite commonly shows complex zoning with respect to Th and other elements.  Similar alteration textures in monazite can be reproduced by alkali-bearing fluids. This implies that these textures in monazite can be metasomatically induced, which in turn means that they can yield information concerning the nature of the fluid responsible for their formation as well as allow for the dating of the metasomatic event, presuming that all the original radiogenic Pb has been removed.

Lecture 3:  Experimental incorporation of Th and U into xenotime utilizing alkali-bearing fluids:  The role of xenotime as a sink for Th and U.

Description:  Xenotime [(Y,HREE,Th,U)(P,Si,Ca)O₄] is a major host for HREE, and is commonly found as an accessory, and sometimes as a major mineral, in ore deposits, and as an accessory mineral in igneous and metamorphic rocks.   Like monazite, it can be metasomatically altered with respect to incorporation of various elements – most commonly Th and U.  Similar to what has been shown for monazite, the fluids responsible for this alteration have been experimentally demonstrated to be alkali-bearing.  The implication from these experiments is that certain fluids with correct chemistry can affect xenotime’s role as a both geochronometer (with preferred removal of Pb) as well as a sink for Th, U and the HREE.  

Lecture 4:  Actinide, HREE, and Pb mobility in alkali- and Ca-bearing fluids: resetting the zircon geochronometer during metasomatism.

Description:  In nature, zircon is one of the principle accessory minerals used for the dating of geologic processes. As a consequence, the stability of zircon in the presence of various possible ore-related, metamorphic, and igneous fluids under a range of P-T conditions, and its subsequent alteration with respect to some of these fluids, has been explored experimentally. Natural alteration of zircon takes place either via dissolution coupled with overgrowth or via fluid-aided coupled dissolution-reprecipitation. This process results in the zircon being partially or totally replaced by new compositionally re-equilibrated zircon or a new mineral phase or both. Alkali-and Ca-bearing fluids have been shown to be quite instrumental in the partial alteration of zircon including both the incorporation and/or depletion of Th and U, depletion of HREE, as well as the complete depletion of ²⁰⁶Pb to below the detection limit of SIMS or LA-ICPMS, such that the zircon geochronometer is reset.

Lecture 5:  Oxide – sulfide relations as a function of pressure, temperature, oxygen fugacity, sulfur fugacity, and rock fluid chemistry.  

Description:  Oxide and sulfide minerals can range in abundance from being major minerals in many ore deposits (e.g. IOA deposits) to being important accessory minerals in igneous and metamorphic rocks.  In all cases the presence of these minerals determines both the oxygen fugacity and sulfur fugacity of the rock, which can be an important factor in the mobility of other trace elements such as U and Au.  Their specific chemistry (both major and minor elements) also provide insights into the chemistry of the fluids (or melts) present during their formation (and the formation of the rock) as well as providing additional insights into the subsequent, fluid-aided chemical evolution of the rock after its formation.

Lecture 6:  REE and actinide mobility on a regional scale in the deep to mid crust: oxidation states and the role of sulfur-bearing alkali-bearing fluids.

Description:  The REE and actinides are important chemical indicators regarding to the role of fluids and melts in the genesis of ore bodies and associated deep to mid crustal processes. As such their mobility or lack thereof can tell us a great deal about the chemistry and oxidation state of fluids in the deep to mid crust and how this affects the whole rock trace element chemistry and oxidation state of the deep to mid crust and associated ore bodies.  

Lecture 7:  The genesis and evolution of Kiruna-type iron oxide-apatite (IOA) ore deposits: fluids vs. melts.  

Description:  Magnetite-apatite ore bodies of the Kiruna type occur worldwide and are associated with volcanic and subvolcanic rocks, which suggest that they represent highly evolved, late-stage, igneous-derived fluids/melts/bodies, associated with subvolcanic magmas, which, after emplacement, are generally metasomatised over a wide range of temperatures.  In most of these ore bodies the magnetite has experienced certain degrees of metasomatic alteration over a wide temperature range including lower grade partial conversion to hematite.  In the fluorapatite, monazite +/- xenotime inclusions are commonly found in areas which have experienced obvious fluid-induced alteration in the form of (Y+REE) + Na + Si + Cl depletion with the fluorapatite serving as the source of P + (Y+REE). Fluid sources could range from 800 – 900 °C, residual (NaCl-KCl brines, HCl, H₂SO₄) grain boundary fluids remaining after the last stages of ore body crystallization to later stage, cooler (H₂O-CO₂-(Na,K)Cl) fluids originating in the surrounding country rock or fluids associated with events such as regional albitization or actinolization. Re-integrating (Y+REE)PO₄ inclusions back into the fluorapatite indicate original (Y+REE)₂O₃ contents ranging from 3 – 5 wt% suggesting that in addition to being mined for their iron ore, the fluorapatite in these ores could be mined for (Y+REE) as well.

Lectures 8 – 10:  Small group discussion, which will cover specific points made in Lectures 1 – 7 as well as points of interest raised by the students regarding their own research projects.  

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二O一八年三月二十三日