Real-time drilling mud gas monitoring for qualitative evaluation of hydrocarbon gas composition during deep sea drilling in the Nankai Trough Kumano Basin

Background

Riverine particles undergo a rapid transformation when they reach estuaries. The rapid succession of hydrodynamic and biogeochemical regimes forces the particles to flocculate, settle and enter the sediment pool. The rates and magnitudes of flocculation depend on the nature of the particles which are primarily affected by the types and quantities of organic matter (OM). Meanwhile, the OM characteristics vary widely between environments, as well as within a single environment due to seasonal climate and land use variability. We investigated the effect of the OM types and quantities through laboratory experiments using natural estuarine particles from the Mississippi Sound and Atchafalaya Bay as well as model mixtures of montmorillonite and organic molecules (i.e., biopolymers (guar/xanthan gums) and humic acid).

Results

Biopolymers promote flocculation but the magnitude depends on the types and quantities. Nonionic guar gum yields much larger flocs than anionic xanthan gum, while both of them exhibit a nonlinear behavior in which the flocculation is the most pronounced at the intermediate OM loading. Moreover, the effect of guar gum is independent of salinity whereas the effect of xanthan gum is pronounced at higher salinity. Meanwhile, humic acid does not affect flocculation at all salinity values tested in this study. These results are echoed in the laboratory manipulation of the natural estuarine particles. Flocculation of the humic acid-rich Mississippi Sound particles is unaffected by the OM, whereas that of biopolymer-rich Atchafalaya Bay particles is enhanced by the OM.

Conclusions

Flocculation is positively influenced by the presence of biopolymers that are produced as the result of marine primary production. Meanwhile, humic acid, which is abundant in the rivers that drain the agricultural soils of Southeastern United States, has little influence on flocculation. Thus, it is expected that humic acid-poor riverine particles (e.g., Mississippi River, and Atchafalaya River, to a lesser degree) may be prone to rapid flocculation and settling in the immediate vicinity of the river mouths when mixed with biopolymer-rich coastal waters. It is also expected that humic acid-rich riverine particles (e.g., Pearl River) may resist immediate flocculation and be transported further away from the river mouth.     

Structural diversity of biogenic carbonate particles in microbial mats

Non-skeletal carbonate particles in microbial mats were studied using thin sections and scanning electron microscopy. The microbial mats form biolaminated units (so-called potential stromatolites) in salterns. This study emphasizes the coexistence of different particle forms and makes a genetic connection between the heterogeneity of the organic substrate built by bacteria and diatoms and their extracellular polymeric substances (EPS). Whereas allochthonous particles are scarce, Lanzarote microbial mats provide various autochthonous surfaces for the attachment of cells and EPS, including sheaths and capsules of cyanobacteria, frustules of diatoms, metabolic products such as gas bubbles, liquid globules and faecal pellets, as well as the carbonate precipitates themselves. Morphologically different carbonate precipitates are: (i) calcified organic clumps (peloids), (ii) particles composed of concentric aragonite and biofilm laminae (ooids and oncoids), (hi) isolated particles floating in gel-supported mats and coated by rims of fibrous cement (cortoids), (iv) particles bound by cryptocrystalline matrices or cement, resulting in aggregate grains and (v) lobate cement which fills out spaces and pores and fixes the particles. Peloids are suggested to represent faecal pellets although microbial systems also generate cell clumps by non-faecal processes. Ooid and oncoid constructions clearly record alternating processes of biofilm accumulation and aragonite encrustation. Further characteristic features of carbonate particles generated within a microbial mat are: (i) an irregular distribution ranging from isolated particles floating within the gel-like matrix to closely packed particles, (ii) the amalgamation of different particle types (e.g. peloids and ooids) in aggregate grains, (iii) the heterogeneous nature of nuclei comprising bacterial clumps, intraclasts, individual cells, cell colonies and bubbles, (iv) the enrichment of remains, casts and imprints of cells within precipitates and (v) deformation (e.g. truncated cortices) of particles.     

云南省富乐分散元素多金属矿床地质特征 —一个分散元素超常富集的铅锌矿床

云南富乐分散元素多金属矿床位于扬子地台西南缘,川滇黔铅锌多金属成矿域东南部,是一个中型的铅锌矿床,伴生Cd、Ge、Se、Ga四种具有工业价值的分散元素,其中Cd、Ge、Se储量达到大型矿床规模。矿体赋存于二叠系茅口组二段白云岩中的层间破碎带内,形态呈透镜状、似层状、脉状,矿体一般长100～1000m,宽50～500m,厚0.5～25m。矿石发育粗粒结构,角砾状构造。矿石矿物主要为闪锌矿、方铅矿,脉石矿物主要为白云石、方解石,分散元素主要呈类质同像形式赋存于闪锌矿中。分散元素富集的原因是含有机质的古油田卤水对矿源层——石炭、二叠纪地层中Pb、Zn、Cd、Ge、Se、Ga的强烈萃取,分散元素主要富集在闪锌矿中。     

中条山地区八一铜矿床中白钨矿的发现及其找矿意义

中条山地区是我国重要铜矿基地之一,虽然区域资料中有钨的化探异常,但以往没有发现有价值的钨矿。文章在八一铜矿研究过程中,通过X射线荧光光谱野外快速分析仪检测、荧光灯检查、光薄片鉴定和电子探针分析,查定出含铜矿脉中赋存白钨矿矿物,其共伴生矿物主要是黄铜矿、闪锌矿和方铅矿,脉石矿物以方解石、白云石和石英为主。通过对白钨矿矿物、金属硫化物、主要脉石矿物的电子探针分析,结合碳同位素组成,初步判断八一铜矿为岩浆热液成因。八一铜矿脉中白钨矿的发现,不但对深入研究我国钨矿的区域成矿规律具有重要意义,也有助于丰富中条山地区的矿床学研究内容,拓展找矿思路。     

煤系固废基绿色充填材料制备及其性能研究

充填技术是绿色开采的重要组成部分,研发成本低廉、性能可靠、低碳环保的充填材料,是发展充填技术的关键。采用煤矸石(CG)和煤系偏高岭土(MK)为原材料制备煤系固废基绿色充填材料,探讨配合比和碱激发剂对充填材料强度以及流动度的影响,并结合X射线衍射(XRD)、傅里叶变换红外吸收光谱仪(FTIR)、热重分析(TG)和扫描电镜能谱分析(SEM-EDS)等表征手段,揭示充填强度发展机理。综合强度、流动性和环境指标,优化充填材料配比。研究结果表明:绿色充填材料体系中,煤系偏高岭土通过碱激发水化反应起到胶凝作用,体系强度随偏高岭土的增加呈线性增长,磨细的煤矸石充当惰性填料,协同Na₂SiO₃改善流动性。该充填材料主要水化产物为N―A―S―H和沸石,Si―O―Si发生聚解,随即四面体Al―O键部分取代Si―O键,由(SiO₄)4?变成(AlO₄)4?,进一步聚合形成Si―O―Al基团。当碱激发剂中Na₂SiO₃与NaOH比例为1∶1时,聚合程度最高。水化产物填充了煤矸石颗粒间孔隙,使基质致密,提高充填材料强度。综合指标评价推荐偏高岭土与煤矸石的配比为3∶7,此时不仅满足强度和流动性的要求,而且碳排放指数仅有0.257。本研究为开发成本低廉、性能可靠、低碳环保的充填材料提供新的思路,具有较好的实用性和经济性。      

不透明矿物所含单个低盐度流体包裹体液相组分SAM/AES实验研究:Ⅰ.原理与方法

针对与矿石矿物共存透明脉石矿物所含流体包裹体并不完全代表成矿流体，红外显微技术及EPMA、SEM等常规表面分析手段无法满足不透明矿石矿物所含单个低盐度流体包裹体研究的实际困难，本文首次成功地应用具同步扫描成象功能、电子束斑空间分辨率较高、信噪比较好的PHI595SAM／AES这一当代高灵敏表面分析技术，按单矿物分选→二次去离子水反复超声清洗→外真空热爆→在金属铟片上压制成样的实验流程对新疆阿尔泰多拉纳萨依金矿床含金黄铁矿所含单个低盐度流体包裹体的液相组成进行了静态定点分析，实验取得了满意结果。     

粤北棉花坑铀矿床矿物共生组合特征及其意义

基于棉花坑矿床不同类型铀矿石中矿物共生组合关系研究,讨论了棉花坑矿床成矿作用过程中铀的沉淀富集机制。研究结果显示,棉花坑矿床铀矿体主要呈脉状充填或细脉浸染状产出;铀矿石类型包括萤石型、碳酸盐型、硅质脉型和红化型。虽然不同矿石类型中成矿期形成的脉石矿物种类存在差异,但均表现出以下共性特点:铀矿物赋存于脉状充填矿石的中心部位或两壁,或与成矿期脉石矿物相间排列;或呈细脉状、浸染状赋存于碎裂蚀变花岗岩内;与成矿期脉石矿物(主要包括方解石、萤石、微晶石英)镶嵌生长;铀矿物与黄铁矿以集合态或相对独立态密切共生,两者之间及其与成矿期脉石矿物晶体之间界线平直,晶形完好,镶嵌生长。认为棉花坑矿床铀矿石中黄铁矿与铀矿物之间不存在先后的成生关系,均为成矿流体共结晶产物;铀沉淀成矿与氧化还原作用无关,减压、温度下降以及成矿流体p H值、溶解度(饱和度)变化,是制约铀矿物以及相关脉石矿物结晶沉淀的主要因素。     

鄂东南付家山脉石英矿杂质特征及其用作高纯石英原料的潜力

作为战略性矿产资源之一,高纯石英已广泛应用于集成电路、半导体芯片、太阳能等高新技术产业中,但是能够生产高纯石英的原料矿床极为稀缺,我国尤为紧缺高纯石英原料矿。鄂东南地区是湖北省脉石英矿床的主要分布区。本文针对鄂东南付家山脉石英矿床,通过光学显微镜、扫描电子显微镜观察了脉石英的脉石矿物类型和包裹体特征,采用电感耦合等离子发射光谱法(ICP-OES)对原矿进行了微量元素分析,旨在获得付家山脉石英矿床的杂质元素特征,进而评价矿床用作高纯石英原料的潜力。结果表明,付家山脉石英矿石SiO₂含量大于99.95%,杂质元素主要为Al、K、Fe、Ti、Ca等,脉石矿物主要有白云母、钾长石、铁氧化物等,流体包裹体较为发育。杂质元素分析结果表明,付家山脉石英原矿质量达到低端高纯石英标准,经传统工艺提纯后,可能具有生产中高端高纯石英的潜力。     

Direct visualization of clay microfabric signatures driving organic matter preservation in fine-grained sediment

We employed direct visualization of organic matter (OM) sequestered by microfabric signatures in organo-clay systems to study mechanisms of OM protection. We studied polysaccharides, an abundant class of OM in marine sediments, associated with the nano- and microfabric of clay sediment using a novel application of transmission electron microscopy, histochemical staining (periodic acid-thiosemicarbazide-silver proteinate), and enzymatic digestion techniques. We used two experimental organo-clay sediment environments. First, laboratory-consolidated sediment with 10% chitin (w/w) added was probed for chitin before and after digestion with chitinase. Second, fecal pellets from the polychaete Heteromastus filiformis were used as a natural environment rich in clay and polysaccharides. Sections of this material were probed with silver proteinate for polysaccharides before and after digestion with a mixture of enzymes (amylase, cellulase, chitinase, dextranase, and pectinase). In both environments, chitin or other polysaccharides were found within pores, bridging clay domains, and attached to clay surfaces in undigested samples. Digested samples showed chitin or polysaccharides more closely associated with clay surfaces and in small pores. Our results imply protective roles for both sorption to clay surfaces and encapsulation within clay microfabric signatures.     

云南禄丰鹅头厂铁铜矿床中稀土矿物的发现及意义

云南禄丰鹅头厂铁铜矿床是滇中地区著名的元古宙含铜富铁矿床之一,矿床中除了铁、铜等资源外,还伴生少量的稀土组分。本文利用国际上矿物与地质行业前沿的矿物自动分析测试方法——矿物表征自动定量分析系统(AMICS),结合扫描电镜-能谱(SEM-EDS)显微结构原位分析技术,完成了常规岩矿鉴定手段难以完成的矿物定量识别和鉴定,首次在禄丰鹅头厂铁铜矿床中发现了氟碳钙铈矿、氟碳铈矿、褐钇铌矿等独立的稀土矿物。其中,氟碳钙铈矿主要富集在条纹条带状矿石中,分布极不均匀,局部富集,主要呈微细粒半自形至它形粒状晶体,多为微细粒的不规则粒状集合体,与磁铁矿间隙中的方解石和绿泥石等脉石矿物紧密共生,在氟碳钙铈矿颗粒中普遍含有呈板状或柱状、片状、针状的微细粒氟碳铈矿;褐钇铌矿也主要富集在条纹条带状矿石中,呈细小的不规则粒状,与铁氧化物边缘缝隙中的绿泥石等脉石矿物紧密共生。X射线能谱分析表明,氟碳钙铈矿和氟碳铈矿富含轻稀土元素,以Ce、Nd、La为主,含量一般Ce La Nd,含少量Pr、Y等元素;褐钇铌矿中主要金属元素有Nb、Y、Ce、Nd、Fe、Ti、Mg、Ca、U等,其中Nb的含量较高,稀土元素以Y为主,并含少量Ce、Nd等。稀土矿物的发现,对探讨该矿床及整个滇中地区前寒武纪(中元古代)铁-铜(-稀土)矿床的成因有着一定的指示意义。根据矿床中稀土-铁氧化物的产出特征和区域成矿地质背景,结合前人研究成果,认为鹅头厂矿床中稀土-铁氧化物的形成与Columbia超大陆裂解时的深部(地幔)岩浆活动有关,并受到多期次后期热液事件的叠加改造。     

云南会泽铅锌矿床分散元素镉锗镓的富集规律

本文利用电子探针和等离子质谱分析手段,对会泽铅锌矿床矿物和矿石的分散元素镉锗镓进行了分析研究,认为矿床中分散元素镉、锗、镓的赋存状态以类质同象形式存在。矿床以富集镉、锗为特征,其中镉主要富集于闪锌矿之中,锗和镓主要富集于方铅矿之中。     

Typomorphism of pyrite of the Sukhoi Log deposit (East Siberia)

The typomorphic features of pyrite of the Sukhoi Log deposit were studied by a set of volumetric and surface methods: electron probe microanalysis, scanning electron and probe microscopy, powder X-ray diffraction, X-ray photoelectron and Auger electron spectroscopy, atomic-absorption spectrometry in the SSADSC (method of statistical sample of analytical data for single crystals) version, and atomic-emission spectrometry. Pyrite from the Sukhoi Log deposit has the following distinctive features: permanent presence of sulfite ion, which often dominates over other surface sulfur anions; weakly determined size dependence of the content of uniformly distributed Au owing to the presence of an internal concentrator of gold—dispersed carbonaceous material—in pyrite from ore zones; cell sculptures of the crystal faces, which appeared owing to the nanofragmentation of the growth surface; micro- and nanoinclusions of carbonaceous phases within crystals, associated with defects in their structure; and thin films enriched in O and C on the surface of and within the crystals. It has been shown that gold-sulfide mineralization at the Sukhoi Log deposit formed in a single ore-generating hydrothermal system, in which gold, sulfur, and carbon belonged to a microparagenesis. Some features (composition of surface, characteristics of submicroscopic structure, and elemental composition) evidence that the conditions of crystallization of pyrite in inter-ore space were different from the conditions of its genesis in the ore zones, which suggests the presence of at least two genetic types of pyrite. Carbonaceous micro- and nanoparticles and O- and C-containing films can favor an increase in the adsorption of gold from cyanide solutions on pyrite. To reduce this effect during gold recovery, a technique for surface modification should be elaborated. The ways for solving the most complicated problems dealt with the source of noble metals (NM) and the ore specialization of the deposit have been outlined. For this purpose, a detailed analysis of the main ore minerals for trace-element speciation is required. In the case of the magmatic source of NM, correlation between the contents of Au and PGE structural forms should exist. On the other hand, there is no correlation between the structural forms of Au or Pt and elements whose contents in fluid are determined by the host rock rather than the magmatic source.     

Enhancing dispersion of halloysite nanotubes via chemical modification

Uniform and dispersed halloysite nanotubes (HNTs) were obtained using sodium dodecyl sulfate (SDS) to disperse the halloysite suspension. The dispersed HNTs were characterized by X-ray diffraction, scanning electron microscope, energy-dispersive spectrometry, transmission electron microscope, Fourier transform infrared spectroscopy, thermogravimetry–differential scanning calorimetry and zeta potential. The results indicated that SDS was adsorbed and scattered on the HNTs, which could enhance the stability and dispersibility of suspension by the electrostatic effect. The zeta potential of dispersed HNTs became larger than that of the raw within the pH ranging from 2.5 to 11.9, which reached ?31 mV at pH around 8 when the concentration of SDS was 1.22 g/L. The diameter of dispersed HNTs ranged from 0.6 to 1.2 μm. A corresponding dispersive mechanism was investigated.     

天然黏土矿物和腐殖酸对纳米乳化油吸持的实验研究

为探讨天然黏土矿物及有机质对纳米乳化油在多孔介质中迁移滞留的影响，本文选取高岭石和蒙脱石这两种黏土矿物以及有机质的典型代表腐殖酸，开展了单一矿物、有机质及有机矿质复合物对纳米乳化油的吸持批实验研究，并运用比表面积全分析、扫描电镜(SEM)、傅里叶红外光谱(FTIR)、X射线衍射(XRD)等技术手段探讨了吸持机理。实验结果表明，介质对纳米乳化油的吸持均符合Freundlich模型；单一矿物及腐殖酸对纳米乳化油的吸持能力表现为：蒙脱石>腐殖酸>高岭石，有机矿质复合样品的吸持能力表现为：蒙脱石-腐殖酸>高岭石-腐殖酸，且均大于其对应的单一样品，出现了“1+1>2”的现象，表明介质组成越复杂，对纳米乳化油的吸持滞留程度越大。进一步分析证实，纳米乳化油主要通过氢键和疏水作用吸持在矿物和腐殖酸表面，表面结构性质是高岭石和蒙脱石吸持过程中的主导因素，因此蒙脱石具有更强的吸持能力，而腐殖酸的吸持主要通过颗粒间聚集作用来实现；对于复合样品，吸持主要通过氢键、配体交换和疏水作用结合来实现。腐殖酸与矿物的复合会增加吸持位点并且增强矿物表面疏水性，从而促进吸持。腐殖酸与纳米乳化油的共吸...     

Composition,morphology, and origin of phosphate pellets: Evidence from phosphorites of the Lesser Karatau

The global Vendian-Cambrian epoch of phosphate accumulation is marked by the virtually synchronous appearance of giant sedimentary basins, where the largest phosphate-bearing provinces were formed in a relatively short time span. The paper is devoted to one of the main problems in phosphate geology, namely the origin of phosphate pellets. They are observed as microscopic particles in the stratified microgranular phosphorites formed during the Vendian-Cambrian epoch. Different forms of pellets from the productive formation of the Lesser Karatau were studied with the scanning electron microscope. The morphogenetic comparison of phosphate particles and microbiota found in the Vendian-Cambrian or older rocks was carried out. The distribution of major chemical elements in different pellets was studied for the first time. Based on the results obtained, regularities of the vertical and lateral distribution of phosphate pellets in the Lesser Karatau and the issue of their origin is discussed.     

河南嵩县下蒿坪金矿工艺矿物学研究

通过化学分析、扫描电镜以及工艺矿物学自动定量分析系统(MLA)等测试方法对河南嵩县下蒿坪金矿进行了系统的工艺矿物学研究,包括原矿化学组成、矿物组成、金的赋存状态、主要载金矿物嵌布特征以及矿物解离特性等。结果表明,该金矿中主要可回收的有价金属为金,其品位为3.75×10^-6。该金矿的原矿矿物主要由石英、钾长石、钠长石、黄铁矿和铁白云石组成,此外还有少量的赤铁矿、萤石、白云石以及方解石。原矿中的金主要赋存在黄铁矿中,而黄铁矿大部分以细粒、微细粒形式嵌布在石英和长石颗粒中。原矿中自然金的含量非常少,多以单独的自然金颗粒形式存在。原矿磨至P₈₀=0.074 mm(-0.074 mm粒级含量占80%)时载金矿物黄铁矿、方铅矿、闪锌矿的单体解离度相对较高,有利于通过浮选回收。     

乳腺纤维腺瘤病灶中钙化的矿物学研究

选取8例乳腺纤维腺瘤的钙化样品,利用光学显微镜（OM）、环境扫描电镜（ESEM）、高分辨透射电镜（HR-TEM）、显微红外光谱仪（FTIR）、微区X射线衍射等矿物学方法对样品进行了原位和分离后形貌、结构及成分的测试分析,探讨了病灶中钙化的矿物学特征,初步探讨了钙化的组成及形成机理。研究结果表明,乳腺纤维腺瘤中的钙化是由病变后期玻璃样变性胶原中的羟基和羧基为钙化提供了成核位点,伴随病情发展最后形成OM下可见的以羟磷灰石为主要成分的坏死钙化。     

Geological and geochemical constraints on the genesis of the Xiangquan Tl-only deposit,eastern China

The Xiangquan Tl deposit, located in the northern part of the Middle–Lower Yangtze Valley metallogenic belt, eastern China, is the only known Tl-only deposit. It is hosted in micritic limestone, marl and mudstone of the Lower Ordovician Lunshan Formation. The orebodies are controlled by the Xiao–Xiaolongwang–Dalongwang anticline and two reverse faults, and are generally stratabound and lenticular. Tl is only ore metal contained in disseminated, massive, brecciated and banded ores. The ore is composed of Tl-bearing pyrite, and gangue minerals quartz, fluorite, barite and carbonate. Alteration minerals include fluorite, barite, fine grained quartz and carbonate. Tl occurs isomorphously replacing iron in the lattice of pyrite, and less commonly as tiny independent Tl-bearing minerals which may be lafossaite (TlAsS₂) or lorandite (TlCl) appearing as 0.1–1 μm-sized cubic crystals. Xiangquan is a submarine sedimentary deposit and demonstrates that Tl, as a normally dispersed element, can form not only part of poly-metallic deposits but also as independent Tl deposits.     

Applied Mineralogical Studies on Iranian Titanium Deposits

Qara-aghaj and Skandian as hard rock titanium deposit and Kahnooj one as a placer deposit were investigated from applied mineralogical point of view. The mineralogical studies were carried out using XRD, XRF, optical microscopy, scanning electron microscopy and microprobe analysis. These studies indicated that ilmenite and magnetite are main valuable minerals in the studied ores. Pyroxene, olivine and plagioclase are the main gangue minerals in Qara-aghaj ore while chlorite and plagioclase are the major gangue minerals in Skandian ore. Plagioclase, clinopyroxene, amphibole, feldspate and some quartz are the important gangue minerals in kahnooj deposit. In all three ores ilmenite is mainly in the form of ilmenite grains but some lamellae of ilmenite with thickness between 0.1 to 20 μm have been occurred as exsolution textures inside magnetite grains, where the magnetite here can be referred to as ilmenomagnetite. In the hard rock ores some fine ilmenites have been disseminated in silicate minerals. The liberation degree of granular ilmenite was determined 150, 140 and 200 μm for Qara-aghaj, Skandian and Kahnooj, respectively. So, only the granular form of ilmenite is recoverable by physical methods. Some sphene and rutile as titanium containing minerals were observed mainly inside ilmenite phase in kahnooj ore. Some fine rutile was also found inside Skandian ilmenite while there were not any other titanium minerals inside Qara-aghaj ilmenite. Apatite is another valuable mineral which was found only in Qara-aghaj ore. Using SEM and microprobe analysis it was found that there are different amounts of exsolved fine lamellae of hematite inside ilmenite in Qara-aghaj and Kahnooj ores while it was not observed in Sckandian one. The average contents of TiO2 in the lattice of Qara-aghaj, Skandian and Kahnooj ilmenite were determined 51.13, 50.9% and 52.02%, respectively. FeO content of ilmenite lattice for all three samples is clearly lower than the theoretical content. This is due to the substitution of Mg and Mn for some Fe2+ ions in the ilmenite lattice. V2O3 content of magnetite lattice is up to 1%. So, magnetite can be a suitable source for production of vanadium as a by-product in all three deposits.     

Nickel geochemistry of a Philippine laterite examined by bulk and microprobe synchrotron analyses

The Ni geochemistry of limonite and saprolite laterite ores from Pujada in the Philippines has been investigated using a mixture of laboratory and synchrotron techniques. Nickel laterite profiles are typically composed of complicated mineral assemblages, with Ni being distributed heterogeneously at the micron scale, and thus a high degree of spatial resolution is required for analysis. This study represents the first such analysis of Philippine laterite ores. Synchrotron bulk and microprobe X-ray absorption spectroscopy (XAS), comprising both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopies, together with synchrotron microprobe X-ray fluorescence microscopy (XFM) and diffraction (XRD) have been applied to provide quantitative analysis of the mineral components and Ni speciation.Synchrotron microprobe EXAFS spectroscopy suggests that the limonite Ni is associated with phyllomanganate via adsorption onto the Mn oxide layers and substitution for Mn within these layers. Laboratory scanning electron microscopy, coupled to electron dispersive spectroscopy analyses, indicates that Ni is also associated with concentrated Fe containing particles and this is further confirmed by synchrotron bulk and microprobe investigation. Linear combination fitting of the bulk EXAFS limonite data suggests 60 ± 15% of the Ni is associated with phyllomanganate, with the predominant fraction adsorbed above vacancies in the MnO₆ layers with the remainder being substituted for Mn within these layers. The remaining 40 ± 10% of the Ni in the limonite ore is incorporated into goethite through replacement of the Fe. In the saprolite ore, 90 ± 23% of the Ni is associated with a serpentine mineral, most likely lizardite, as a replacement for Mg. The remaining Ni is found within phyllomanganate adsorbed above vacancies in the MnO₆ layers.