巢湖水-气界面N2O通量排放特征及影响因素

湖泊是温室气体氧化亚氮(N₂O)的潜在排放源,但由于自然环境以及人类活动的差异,其N₂O排放规律也存在特殊性和地域性。为探究巢湖N₂O排放通量的时空特征,利用静态暗箱-气相色谱法于2018年3月至2019年12月对巢湖不同区域(东、中、西)N₂O的排放进行观测。结果表明,巢湖水体N₂O年均排放通量为(25.14±55.01)μg/(m²·h),表现为N₂O的“源”,且具有较为明显的时空分布规律。在时间分布上,季节变化趋势呈现“M”形模式,7月出现最小值且表现为N₂O的“汇”((-12.97±16.32)μg/(m²·h)),在6月和8月为峰值,全年最大值出现在8月((68.25±78.05)μg/(m²·h)),极值均出现在夏季。在空间分布上,东、中、西3个湖区N₂O排放通量差异显著(P=0.03),N₂O排放通量最大值((4...     

邻菲啰啉助溶保护-容量法测定电气石中的氧化亚铁

电气石是一种含硼的铝硅酸盐矿物,是成岩成矿作用的灵敏示踪剂,通过测试围岩电气石中氧化亚铁的含量,可以鉴定电气石所赋存岩床的成因。但是,国内外目前尚无系统的电气石化学成分标准分析方法及电气石化学成分标准物质,针对电气石中氧化亚铁分析方法的研究更是罕有报道。该文通过在溶矿过程中加入邻菲啰啉,与亚铁形成络合物,对亚铁能够起到较好的助溶和保护效果,建立了在聚四氟乙烯坩埚中加入邻菲啰啉、氢氟酸及硫酸,中高温电热板加热溶矿,重铬酸钾容量法测定电气石中的亚铁的方法。该方法的精密度(RSD,n=12)为0.59%,样品加标回收率为99.3%~100.9%。经过多家实验室间的比对实验,证明该方法准确度高,具有较好的应用效果。     

攀西地区铁钛氧化物矿物的显微结构

本文用矿石显微镜及单晶X射线分析方法,研究了攀枝花—西昌地区铁钛氧化物矿物的显微结构共生组合特点、各出溶相间的关系和分布方位以及不同岩石和矿石显微结构共生组合上的差异。业已查明它们受岩浆旋回和岩石类型所控制。本文指出了磁铁矿-钛铁晶石固溶体显微出溶结构可能是拐点分解经调制结构后的终期产物。     

富钴结壳生长过程中铁锰氧化物矿物组合的变化

富钴结壳的矿物学研究是一个难点，本文运用电子探针微区分析结合X射线衍射和矿相显微镜观察的综合方法对富钴结壳中的铁锰氧化物矿物组合及其组分变化进行了研究，研究发现，富钴结壳是从与胶状粘土类混合共沉积开始生长的，结壳内部的韵律层和柱状构造也是始于粘土层终于粘土层的；铁锰团粒的核心一般是较纯的水羟凶国矿小核心，可能是在生物媒介作用下在水体中形成后沉降叠积的，FM、FPE海山结壳的中层存在一较纯水羟锰矿层，但该层中Co含量FM15比FPE06低得多，可能反映了FM15在该层形成时Co通量较低，而该层在FN12中不存在，反映了区域环境的较大差异，在FN12火焰状构造亚带存在Mn氧化物和Fe氧化物的极度分异现象，可能反映了结壳形成环境的重大变化。     

Hydration vs. oxidation: Modelling implications for Fe–Ti oxide crystallisation in mafic intrusions, with specific reference to the Panzhihua intrusion, SW China

Recent work on the Panzhihua intrusion has produced two separate models for the crystallisation of the intrusion:（1） low-Ti,high CaO and low H₂O（0.5 wt.%） parent magma（equivalent to Emeishan low-Ti basalt） at FMQ;and（2） high-Ti,low CaO and higher H₂O（>1.5 wt.%） parent magma（equivalent to Emeishan high-Ti basalt） at FMQ + 1.5.Modelling of these parent magma compositions produces significantly different results. We present here detailed f（O₂） and H₂O modelling for average compositions of both Emeishan high-Ti and low-Ti ferrobasalts in order to constrain the effects on crystallisation sequences for Emeishan ultra-mafic -mafic layered intrusions.Modelling is consistent with numerous experimental studies on ferro-basaltic magmas from other localities（e.g.Skaergaard intrusion）.Modelling is compared with the geology of the Panzhihua intrusion in order to constrain the crystallisation of the gabbroic rocks and the Fe-Ti oxides ore layers.We suggest that the gabbroic rocks at the Panzhihua intrusion can be best explained by crystallisation from a parent magma similar to that of the high-Ti Emeishan basalt at moderate H₂O contents（0.5-1 wt.%） but at the lower end of TiO₂ content for typical high-Ti basalts（2.5 wt.%TiO₂）. Distinct silicate disequilibrium textures in the Fe-Ti oxide ore layers suggest that an influx of H₂O may be responsible for changing the crystallisation path.An increase in H₂O during crystallisation of gabbroic rocks will result in the depression of silicate liquidus temperatures and resultant disequilibrium with the liquid.Continued cooling of the magma with high H₂O then results in precipitation of Mt-Uv alone. The H₂O content of parent magmas for mafic layered intrusions associated with the ELIP is an important variable.H₂O alters the crystallisation sequence of the basaltic magmas so that at high H₂O and f（O₂） Mt -Uv crystallises earlier than plagioclase and clinopyroxene.Furthermore,the addition of H₂O to an anhydrous magma can explain silicate disequilibrium texture observed in the Fe-Ti oxide ore layers.     

塔里木克拉通东北缘二叠纪镁铁质岩浆氧化物与硫化物成矿条件对比

塔里木克拉通东北缘坡北、磁海等地二叠纪幔源岩浆活动形成了镍钴硫化物矿床和铁钴氧化物矿床,两者赋矿镁铁-超镁铁岩体的年龄相近(290～260 Ma),主、微量元素和Sr-Nd-Hf同位素组成相似,分配系数接近的微量元素比值分布于相同趋势线,揭示两者岩浆源区相同,可能为俯冲板片流体交代的亏损地幔或软流圈地幔。两类矿床镁铁-超镁铁质岩中Co与Ni含量正相关,Co主要富集在基性程度高的岩石中;块状硫化物与磁铁矿矿石中Co与Ni相关性差,Co和Ni具有不同的富集机制,Co热液富集作用明显。北山镁铁-超镁铁杂岩体是地幔柱相关软流圈上涌,诱发俯冲板片交代的亏损岩石圈地幔发生部分熔融,形成的高镁母岩浆演化过程中经历壳源混染、硫化物饱和富集镍钴形成铜镍钴硫化物矿床,富铁母岩浆氧逸度高、富水,岩浆分离结晶磁铁矿、叠加热液作用富集钴,形成铁钴氧化物矿床。     

Composition and Assemblage Characteristics of Magnetic Minerals in Layer S_(5-1) of Xifeng and Duanjiapo Sections

Magneticmineralsintheloess paleosolseriesaccountforabout 1 % -2 %ofthetotal (LiuTungshengandZhangZhonghu ,1 962 ) .Duetotheiraerolianorigin ,themagneticmineralsarecomplicatedincomposition ,largeingrainsizerange ,andsignificantlydifferentincrystallinity .Asaresult,researchonthesemagneticmineralswouldbesetwithalotofdifficulties.Previousre searchersemployedopticalmicroscopic ,X raydiffractionandM ssbauerspectrometrictechniquestostudythemagneticmineralsintheloess paleosolseries,andchieflyontheb…     

Shock-induced temperatures of MgO

Shock-compressed MgO radiates thermally at temperatures between 2900 and 3700 K in the 170–200 GPa pressure range. A simple energy-transport model of the shocked-MgO-targets distinguishes between different shock-induced radiation sources in these targets and provides estimates of spectral absorption-coefficients, α _ΛMgO, for shocked MgO (e.g. at 203 GPa, α _ΛMgO˜ 630, 7500, 4200 and 3800 m⁻¹, at 450, 600, 750 and 900 nm, respectively). The experimentally inferred temperatures of the shock-compressed states of MgO are consistent with temperatures calculated for MgO assuming that (1) it deforms as an elastic fluid, (2) has a Dulong-Petit value for specific heat at constant volume in its shocked state, and (3) undergoes no phase transformation below 200 GPa.