Otway Rees协议的安全分析

互联网的迅速发展引起人们对协议安全性的关注,现在国际上流行安全协议的分析方法集中在形式化验证方面,其中BAN逻辑是一种方法。本文通过使用BAN逻辑证明O tway Rees协议的安全性,同时也得出BAN逻辑在证明协议安全性方面的一些缺陷。

REE Geochemistry of Fluorite from the Maoniuping REE Deposit,Sichuan Province,China:Implications for the Source of Ore-forming Fluids

Fluorite is one of the main gangue minerals in the Maoniuping REE deposit, Sichuan Province, China. Fluorite with different colors occurs not only within various orebodies, but also in wallrocks of the orefield. Based on REE geochemistry, fluorite in the orefleld can be classified as the LREE-rich, LREE-flat and LREE-depleted types. The three types of fluorite formed at different stages from the same hydrothermal fluid source, with the LREE-rich fluorite forming at the relatively early stage, the LREE-flat fluorite in the middle, and the LREE-depleted fluorite at the latest stage. Various lines of evidence demonstrate that the variation of the REE contents of fluorite shows no relation to the color. The mineralization of the Maouiuping REE deposit is associated spatially and temporally with carbonatite-syenite magmatism and the ore-forming fluids are mainly derived from carbonatite and syenite melts.

Origin and Distribution of Grain Dolostone Reservoirs in the Cambrian Longwangmiao Formation,Sichuan Basin,China

Dolostones in the Cambrian Longwangmiao Formation have become one of the most significant gas exploration domains in China. Over a trillion cubic meters of gas reservoirs have been discovered in the Gaoshiti-Moxi area; however, the origins and distribution of the dolostone reservoirs are not well understood. This work discussed the geology and geochemistry of the dolostone reservoirs in the Longwangmiao Formation to determine their origin and distribution. Two understandings are acquired： firstly, a carbonate ramp provided excellent conditions for grain beach deposition, while the presence of a hypersaline lake was favorable for the contemporaneous dolomitization of grain beach deposits. Petrographic and geochemical evidence further confirm that the Longwangmiao dolostone was formed during the contemporaneous stage. Secondly, the reservoir characteristics indicate that the grain beach sediments provide material basis for the development of the Longwangmiao dolostone reservoirs. Reservoir dissolution simulation experiments show that the porosity of the reservoirs was formed by dissolution during contemporaneous and burial stages. The dissolution pores formed during the contemporaneous stage were controlled by sequence interfaces. The large scale dissolution vugs formed during the burial stage subsequently spread along the pre-existing porosity and fracture zones. This study therefore identified that the development of grain dolostone reservoirs in a shallow water ramp under arid climatic conditions generally met the following conditions：（1） reefal beach deposits lay a foundation for reservoir development;（2） superficial conditions are an important determining factor for reservoir porosity; and（3） burial conditions provide environment for porosity preservation and modification.

Characteristics of porosity and permeability layer of fossil Halimeda reef mineral rock of Miocene in the Xisha Islands and its genetic model

Halimeda is one of the major reef-building algas in the middle Miocene of Xisha, and one of the significant reef-building algas in the algal reef oil and gas field of the South China Sea. However, there have been few reports regarding the characteristics of mineral rocks, reservoir porosity and permeability layers, and sedimentation-diagenetic-evolution of fossil Halimeda systems. The present paper briefly introduces the relevant studies on chlorophyta Halimeda and the research status of oil and gas exploration. Through the 1 043 m core of the Xichen-1 well, we studied the characteristics of the mineral rocks and porosity and permeability of the middle Miocene Halimeda of the Yongle Atoll, identified and described the segments of fossil Halimeda, and pointed out that most of the segment slides are vertical sections in ovular, irregular or long strips. The overwhelming majority of these fossil Halimeda found and studied are vertical sections instead of cross sections. In this paper, knowledge regarding the cross sections of fossil Halimeda is reported and proven to be similar with the microscopic characteristics of modern living Halimeda;fossil Halimeda are buried in superposition;it is shown that there are different structures present, including typical bio-segment structure, and due to its feature of coexisting with red alga, tying structure, twining structure and encrusting structure are all present;and finally, it is suggested to classify the fossil Halimeda into segment algal reef dolomites. In addition, all of the studied intervals are moderately dolomitized. Secondary microcrystalline-dolosparite dominates the original aragonite raphide zones, and aphanitic-micrite dolomite plays the leading role in the cortexes and medullas;in the aragonite raphide zones between medulla and cysts, secondary dissolved pores and intercrystalline pores are formed inside the segments, and algal frame holes are formed between segments;therefore, a pore space network system （dissolved pores＋intragranular dissolved pores—intercrystalline pores＋algal frame holes） is established. Segment Halimeda dolomite has a porosity of 16.2%–46.1%, a permeability of 0.203×10^–3–2 641×10^–3μm^2, and a throat radius of 23.42–90.43μm, therefore it is shown to be a good oil and gas reservoir. For the reasons mentioned above, we suggest building the neogene organic reef-modern reef sedimentation-diagenetic-evolution models for the Xisha Islands.

Distribution of REE of Phosphate Concentrate in Wet-Phosphoric Acid Process

There exists the most important REE-bearing phosphorite deposit in Southwest of China. Due to the fact that the REE are present in the form of ions in the lattices of collophanite or carbonatfluorapatite, the REE can be enriched in phosphate concentrate by flotation method. The phosphate concentrate is the main raw materials to produce phosphoric acid, therefore, it is significant to further investigate the distribution rule of REE in wet process. In this paper, the single leaching and recycled leaching technology were carried out to investigate the effect of various parameter conditions on distribution of REE in products. The REE compositions of products were analyzed by Inductively Coupled Plasma Emission Mass Spectrometry (ICP-MS) method. It was found that the acidic value of leaching liquor was the main effect factor on the distribution of REE in products. In single leaching stage, P2O5 concentration of leaching liquor slightly varied from 8% to about 10% when the excessive coefficient of sulphuric acid ranged from 1.03 to 1.05, and the distribution proportions of ∑REO in phosphoric acid solution was lower than 40%. However, in recycled leaching process(the condition similar to practical wet process), with an increase of P2O5 concentration as well as the acidic value of leaching liquor, the distribution proportions of ∑REO in phosphoric acid solution could be decreased to 2.56%. That is to say that under the condition similar to practical wet process, more than 90% of REE of phosphate concentrate became precipitation entering into the phosphogypsum product. This investigation will provide valid reference for reasonably recovering or reserving REE in wet-phosphoric acid process.

Petrologic characteristics and genesis of dolostone from the Campanian of the SK-I Well Core in the Songliao Basin,China

The well SK-I in the Songliao Basin is the first scientific borehole targeting the continental Cretaceous strata in China. Oval concretions, thin laminae and beds of dolostone are found intercalated within mudstone and organic-rich black shale in the Nenjiang Formation of Campanian age. Low ordered ferruginous dolomite is composed of euhedral--subhedral rhombs with cloudy nucleus and light rims formed during the diagenesis, which are typical features of replacement. The heavy carbon isotopes （δ13CPDB -- 1.16-16.0） are results of both the fermentation of organic matter by microbes and degassing of carbon dioxide during the period of diagenesis, and the presence of light oxygen isotopes （δ18OPDB- 18.53--5.1） is a characteristic feature of fresh water influence which means the carbonate may have been altered by ground water or rainwater in the late diagenesis. Marine water incursions into the nor- mally lacustrine basin have been proved by both the salinity of Z value and the occurrence of foraminifera in the same strata where dolomite occurs. Pyrite framboids observed by SEM are usually enclosed in the dolomite crystals or in the mudstones, supporting the sulfate reducing bacteria （SRB）. The formation of both dolomite and pyrite are associated with marine water incursions, which not only supply magnesium ion for dolomite, but also result in limited carbonate precipitation in the basin. The presence of pyrite framboids indicates the development of an anoxic environment associated with salinity stratification in the lake. The dolomite in the Nenjiang Formation is the results of marine water incursions, diagenetic replacement of calcareous carbonate and sulfate reducing bacteria （SRB）.

The role of carbonate-fluoride melt immiscibility in shallow REE deposit evolution

The Lugiin Gol nepheline syenite intrusion, Mongolia, hosts a range of carbonatite dikes mineralized in rare-earth elements(REE). Both carbonatites and nepheline syenite-fluorite-calcite veinlets are host to a previously unreported macroscale texture involving pseudo-graphic intergrowths of fluorite and calcite. The inclusions within calcite occur as either pure fluorite, with associated REE minerals within the surrounding calcite, or as mixed calcite-fluorite inclusions, with associated zirconosilicate minerals. Consideration of the nature of the texture, and the proportions of fluorite and calcite present(～29 and 71 mol%,respectively), indicates that these textures most likely formed either through the immiscible separation of carbonate and fluoride melts, or from cotectic crystallization of a carbonatefluoride melt. Laser ablation ICP-MS analyses show the pure fluorite inclusions to be depleted in REE relative to the calcite. A model is proposed, in which a carbonate-fluoride melt phase enriched in Zr and the REE, separated from a phonolitic melt, and then either unmixed or underwent cotectic crystallization to generate an REE-rich carbonate melt and an REE-poor fluoride phase. The separation of the fluoride phase(either solid or melt) may have contributed to the enrichment of the carbonate melt in REE, and ultimately its saturation with REE minerals. Previous data have suggested that carbonate melts separated from silicate melts are relatively depleted in the REE, and thus melt immiscibility cannot result in the formation of REE-enriched carbonatites. The observations presented here provide a mechanism by which this could occur, as under either model the textures imply initial separation of a mixed carbonate-fluoride melt from a silicate magma. The separation of an REEenriched carbonate-fluoride melt from phonolitic magma is a hitherto unrecognized mechanism for REE-enrichment in carbonatites, and may play an important role in the formation of shallow magmatic REE deposits.

The giant Bayan Obo REE-Nb-Fe deposit,China:Controversy and ore genesis

Bayan Obo ore deposit is the largest rare-earth element（REE） resource,and the second largest niobium（Nb） resource in the world.Due to the complicated element/mineral compositions and involving several geological events,the REE enrichment mechanism and genesis of this giant deposit still remains intense debated.The deposit is hosted in the massive dolomite,and nearly one hundred carbonatite dykes occur in the vicinity of the deposit.The carbonatite dykes can be divided into three types from early to late：dolomite,co-existing dolomite-calcite and calcite type,corresponding to different evolutionary stages of carbonatite magmatism based on the REE and trace element data.The latter always has higher REE content.The origin of the ore-hosting dolomite at Bayan Obo has been addressed in various models,ranging from a normal sedimentary carbonate rocks to volcano-sedimentary sequence,and a large carbonatitic intrusion.More geochemical evidences show that the coarse-grained dolomite represents a Mesoproterozoic carbonatite pluton and the fine-grained dolomite resulted from the extensive REE mineralization and modification of the coarse-grained variety.The ore bodies,distributed along an E-W striking belt,occur as large lenses and underwent more intense fluoritization and fenitization.The first episode mineralization is characterized by disseminated mineralization in the dolomite.The second or main-episode is banded and/or massive mineralization,cut by the third episode consisting of aegirinerich veins.Various dating methods gave different mineralization ages at Bayan Obo,resulting in long and hot debates.Compilation of available data suggests that the mineralization is rather variable with two peaks at～1400 and 440 Ma.The early mineralization peak closes in time to the intrusion of the carbonatite dykes.A significant thermal event at ca.440 Ma resulted in the formation of late-stage veins with coarse crystals of REE minerals.Fluids involving in the REE-Nb-Fe mineralization at Bayan Obo might be REE-F-C02-NaCI-H20 system.The presence of REE-carbonates as an abundant solid in the ores shows that the original ore-forming fluids are very rich in REE,and therefore,have the potential to produce economic REE ores at Bayan Obo.the Bayan Obo deposit is a product of mantle-derived carbonatitic magmatism at ca.1400 Ma,which was likely related to the breakup of Columbia.Some remobilization of REE occurred due to subduction of the Palaeo-Asian oceanic plate during the Silurian,forming weak vein-like mineralization.

Re-interpretation of zircon date in a carbonatite dyke at the Bayan Obo giant REE-Fe-Nb deposit,China

Recent ce-valuation of the dating of the carbonatite dykes associated with the REE-Re-Nb giant deposit at Bayan Obo

半群的Cwrpp Rees根的扩张结构

借助于半群的理想扩张理论,研究了半群的Cwrpp Rees根的扩张结构,证明了Cwrpp Rees根的扩张半群的结构特征,即S是Cwrpp Rees根的扩张半群当且仅当S是有强Cwrpp Rees根的wrpp半群.同时给出了半群的Cwrpp Rees根的几种扩张结构,并通过例子表明Cwrpp Rees根的扩张半群有其独特意义.

Comparisons on Mineralogy and Lithology between Paleozoic Marine and Lacustrine Dolostones, Northern China

1 Introduction Dolomite[Ca Mg(CO3)2],a common mineral in carbonate rocks,can be found in various geological settings from Precambrian to modern age,and is widely reported in almost all sedimentary and digenetic

The Characteristics of the Hydrothermal Exhalative Dolostone of Lucaogou Formation in Santanghu basin and its Geology Setting Indication

The NW-SE trending Santanghu basin is located in Xinjiang,NW China,between Tianshan Mountains and Altai Mountains.The tectonic evolution history of north Xinjiang has long been debated,especially the question when did that area began its intraplate rift evolution stage.This abstract discusses the features and possible origin of the hydrothermal exhalative dolostone of Lucaogou Formation in Santanghu basin,aiming to provide relevant information about this question.The target dolostone are characterized by extreme thin lamina of 0.3cm–1 cm thick.Dolomite,ankerite,potassium feldspar and analcite are dominant composition.Most dolomite is poor crystallized and is in anhedral or subhedral shapes.Ankerite is generally porphyritic,few is in irregular shapes.It has to be noted that the porphyritic ankerite commonly develop zonal textures characterized by rings with various Fe O content.Potassium feldspar and analcite（<50%）are commonly observed in dolostones.Thin sections show some analcite is tetragonal trisoctahedron with harbour–like corrosion rims.Besides,few fragments of carbonatite rocks are observed in Lucaogou Formation and they perform intermittent or scattered distribution in rock layers.Previous work done by our study team showsδ13C PDB values are 4.8‰;1.4‰,6.93‰on average.Theδ18 O PDB values are between-5‰;21.1‰,-10.94‰on average.Paleosalinity calculated byδ13C andδ18 O is between 128.35 and 136.81,134.42 on average.Sr content of dolostones in study area reaches to164×10-6;37×10-6（379.1×10-6 on average）,most dolostone in target area are between 0.70457;.706194, average at 0.705360.Considering either accompanying residual tuff or residual leucite is found via electron probe,this indicates the analcite may derive form analcime phonolite.Furthermore,fragments of carbonatite rocks proves mantle-derived magmatism exist.The rapid variation ofδ18 O indicates multiple interactions of hydrothermal fluids with lake water during Lucaogou sedimentary period.87Sr/86Sr values are much lower than that of crustal silica rocks while are more close to mantle derived rocks,which indicates diagenetic hydrothermal fluid is mantle-origin.It has been reported that dolostone does not intergrow with iron-rich dolostone in study area.According to the latest X diffraction results of cores,iron-rich dolostone distributes rather locally.Given that ankerite commonly develop zonal textures characterized by various Fe O content,we confirm it is due to multiple hydrothermal fluids activities in different hydrothermal vents.There should be abundant hydrothermal vents during Lucaogou period.Deep faults and its relevant fractures built plenty paths for mantle-origin hydrothermal fluids to run up.Different vents owned various fluid properties,so did relevant sedimentation products.Hence we inclined to believe Santanghu basin was at intraplate rift evolution stage,under regional extension condition in late Carboniferous.During early-mid Permian the basin was a starved,deep lacustrine intracontinental rift basin.Accordingly,in northern Xinjiang,ocean basin may close in late Carboniferous and started continental sedimentary development in early Permian.

Biological Function of REE in Plants & Microbes

Rare earth elements （REE） and their compounds years. The bioinorganic chemical research of REE during the are widely applied in agronomic and medical fields for many past few years indicates that REE play important roles in the promotion of photosynthetic rate as well as root absorption, regulation of hormone and nitrogen metabolism, and suppression of microbes, etc. The metallic or non-metallic targets of key biomolecule in various physiological processes can be chosen by REE for the chelation or replacement, which enables REE to regulate the biological functions or behaviors of those biomolecule and consequently leads to significant embodiment of biological function of REE in plants and microbes. Overdose of REE, however, shows an inhibitory effect on living organisms. Therefore, this paper proposes two suggestions that will be available in the extension of full use of REE＇s biological function. One is to obey the dose law of REE and control REE concentrations within a safe range. The other is to further test the bioaccumulation and long-period influence of REE on organisms.

The nature, type, and origin of diagenetic uids and their control on the evolving porosity of the Lower Cambrian Xiaoerbulak Formation dolostone, northwestern Tarim Basin, China

The study on Lower Cambrian dolostones in Tarim Basin can improve our understanding of ancient and deeply buried carbonate reservoirs.In this research,diagenetic fluid characteristics and their control on porosity evolution have been revealed by studying the petrography and in situ geochemistry of different dolomites.Three types of diagenetic fluids were identified:(1) Replacive dolomites were deviated from shallow burial dolomitizing fluids,which might probably be concentrated ancient seawater at early stage.(2) Fine-to-medium crystalline,planar-e diamond pore-filling dolomites(Fd1) were likely slowly and sufficiently crystallized from deep-circulating crustal hydrothermal fluids during Devonian.(3) Coarse crystalline,non-planar-a saddle pore-filling dolomites(Fd2) might rapidly and insufficiently crystallize from magmatic hydrothermal fluids during Permian.Early dolomitizing fluids did not increase the porosity,but transformed the primary pores to dissolution pores through dolomitization.Deep-circulating crustal hydrothermal fluids significantly increased porosity in the early stages by dissolving and then slightly decreased the porosity in the late stage due to Fd1 precipitation.Magmatic hydrothermal fluids only precipitated the Fd2 dolomites and slightly decreased the porosity.In summary,Devonian deep-circulating crustal hydrothermal fluids dominated the porosity evolution of the Lower Cambrian dolostone reservoir in the Tarim Basin.

Characteristics of Geochemical Evolution of Trace Elements and REE in Gejiu Granites, Yunnan Province

The evolution characteristics of Gejiu granites.Yunnan Province are described in terms of theirPetrology,especially their trace elements and REE geochemistry The three major types of Gejiu granites:porphyritic biotite monzonitic granite(stageⅠ),medium-coarse-grained biotite-K-feldspar granite(stage Ⅱ)and two-mica alkali-feldspar granite(stage Ⅲ)are thought to have been formed successively from the samegranite magma source through fractional crystallization(Rayliegh fractionation),because linear correlationsare found between log(Rb/Sr)-log Sn,log(Rb/Ba)-log Sn,log(Rb/Ba)-log(Rb/Sr),log La-log Sr,log Ce-log Sr,log Eu-log Sr,etc In addition.the characteristics of REE distribution patterns in these three major types ofgranites also reflect the magmatic differentiation features of Gejiu granites.Of the three major types,the twomica alkali-feldspar granite of stage Ⅲ nuderwent the strongest differentiation,and thus has the closestgenetic relationship with the Gejiu tin-polymetallic ore deposit Such tin-polymetal mineralized granites arecharacterized by high Rb/Sr and Rb/Ba ratios,low K/Rb and ∑Ce/∑Y ratios and remarkable Eu depletion.

Behavior of REE Fractionation during Weathering of Dolomite Regolith Profile in Southwest China

REE fractionation during the weathering of dolomite has been recognized for decades.A regolith profile on dolomite in southwest Yunnan of China was selected to investigate the behaviors of REE during weathering.The weathering of dolomite is divided into two stages：the pedogenesis stage and soil evolution stage,corresponding to the saprolites and soils respectively in the regolith profile. SiO_2,TiO_2,P_2O_5,Zr,Hf,Nb and Ta were immobile components during the weathering by and large, while Al_2O_3,K_2O and Fe_2O_3 were lost during the soil evolution stage in the physical form（clay minerals probably）.REE were fractionated during the whole weathering of dolomite.The field weathering profile and the lab acid-leaching experiments on dolomite indicate that MREE were enriched clearly relative to other REE during the pedogenesis stage in a ＂capillary ascending-adsorption＂ mechanism, but they did not fractionate clearly in the soil evolution stage.REE were lost and accumulated in the weathering front of dolomite during the soil evolution stage in a ＂physical-chemical leaching＂ mechanism.

Existing forms of REE in gold-bearing pyrite of the Jinshan gold deposit,Jiangxi Province,China

Rare earth element(REE) is widely used in various fields of geology.Study of the existing forms of REE in geological objects is a necessity for us to solve geological problems related with REE.This paper tried to make it clear the existing forms of REE in gold-bearing pyrite in Jinshan gold deposit by stepwise dissolution test with ICP-MS analysis.Results showed that content of REE in fluid-inclusions of gold-bearing pyrite was very low,which only took about 0.07%–0.70% of the ΣREE,and that of pyrite phase ...

Behaviours of REE and Other Trace Elements During Pedological Weathering-Evidence from Chemical Leaching of Loess and Palaeosol from the Luochuan Section in Central China

The chemical leaching method is used for a systematic analysis of distribution characteristics of acid-soluble and acid-insoluble REE and other trace elements from the Luochuan loess deposits. The study shows that the acid-insoluble phase in loess and palaeosol is a stable component of old aeolian dusts and is characteristic of the provenance; the acid-soluble phase is the unstable component in the weathering pedogenic process and reflects rock-forming features after accumulation of aeolian dusts. The acid-insoluble REE and acid-soluble Sr and Pb can be used as geochemical indicators respectively to trace the provenance characteristics and the weathering pedogenic process.

REE Compositions of Lower Ordovician Dolomites in Central and North Tarim Basin,NW China:A Potential REE Proxy for Ancient Seawater

Rare earth element compositions of Lower Ordovician dolomites in the Central and Northern Tarim Basin are studied. Most dolomite samples are more or less contaminated by clay minerals. Their rare earth element compositions have been consequently changed, showing both seawater-like and non-seawater-like features. The clay contamination should be disposed before the REE data are used. Through ICP-MS and ICP-AES analyses, the REE features are well documented. The clay contamination is quantitatively determined by microscopic investigation, trace elements and REE contents. The dolomites, at least in the Tarim Basin, are thought to be pure when their total LREE contents are less than 3×10^-6. Through comparison, the pure dolomites show similarities in REE patterns but differences in REE contents with co-existing pure limestone, which indicates that dolomitization may slightly change the REE compositions. Nevertheless, whatever the change is, the pure dolomites may act as a potential REE proxy for Ordovician seawater, which would be significant for ancient massive dolomite strata that lack limestone.

Contrasting REE Signatures on Manganese Ores of Iron Ore Group in North Orissa, India

The distribution pattern of Rare Earth Elements （REE） in three categories of manganese ores viz. stratiform, stratabound-replacement, and detrital of Precambrian Iron Ore Group from north Orissa, India was reported. These categories of Mn-ore differed in their major and trace chemistry and exhibited contrasting REE signature. The stratiform ores were relatively enriched in ∑REE content （697 μg·g^-1） and their normalized pattern showed both positive Ce and Eu anomalies, whereas the stratabound-replacement types were comparatively depleted in ∑REE content （211 μg·g^-1） and showed negative Ce and flat Eu signatures. The detrital categories showed mixed REE pattern. The data plotted in different discrimination diagrams revealed a mixed volcaniclastic and chemogenic source of material for stratiform categories, and LREE （Light Rare Earth Elements） and HREE （Heavy Rare Earth Elements） are contributed by such sources, respectively. In contrast, the stratabound ore bodies were developed during the remobilization of stratiform ores, and associated Mncontaining rocks under supergene condition followed by the redeposition of circulating mineralized colloidal solutions in structurally favorable zones. During this process, some of the constituents were found only in very low concentration within stratabound ores, and this is attributed to their poor leachability/mobility. The detrital ores did not exhibit any significant characteristic in respect of REE as their development was via a complex combination of processes involving weathering, fragmentation, recementation, and burial under soil cover.