Genesis of the Jianbeigou Gold Deposit on the Southern Margin of the North China Craton: Insights from Fluid Inclusions, H-O-S Isotopes, and Pyrite in situ Trace Element Analyses

The Jianbeigou gold deposit is a typical lode gold deposit in the Qinling metallogenic belt, located on the southern margin of the North China Craton. Three stages of the hydrothermal process can be distinguished, including the quartz ± pyrite, quartz-polymetallic sulfide, and quartz-carbonate ± pyrite stages. From the early to late stages, the homogenization temperatures of primary fluid inclusions are 281–362°C, 227–331°C, and 149–261°C, respectively. The corresponding salinities estimated for these fluids are 3.9–9.9 wt%, 0.4–9.4 wt%, and 0.7–7.2 wt% Na Cl equiv. Combined with laser Raman spectroscopy data, the ore-forming fluid belongs to a H_(2)O-CO_(2)-Na Cl ± CH_4 system with medium–low temperature and salinity. The δ~(18)Ofluid and δD values for the quartz veins are-1.0‰ to 6.0‰ and-105‰ to-84‰, respectively, which indicates that the ore-forming fluid is of mixed source, mainly derived from magma, with a contribution from meteoric water. Pyrite has been identified into three generations based on mineral paragenetic sequencing, including Py1, Py2, and Py3. The pyrites have δ~(34)S sulfur isotopic compositions from three stages between 3.7‰ and 8.4‰, indicating that sulfur mainly originated from magma. Te, Bi, Sb, and Cu contents in pyrite were all high and showed a strong correlation with Au concentrations. Native gold and the Au-Ag-Bi telluride minerals were formed concurrently, and the As concentration was low and decoupled from the Au content. Therefore, Te, Bi, Sb and other low-melting point chalcophile elements play an important role for gold mineralization in arsenic-deficient ore-forming fluid. Combined with the geological setting, evolution of pyrite, and ore-fluids geochemistry, we propose that the Jianbeigou deposit can be classified as a magmatic–hydrothermal lode gold deposit. Gold mineralization on the southern margin of the North China Craton is related to Early Cretaceous magmatism and formed in an extensional setting.

The Middle Miocene lobe-shaped and band-shaped submarine fans in the Lingshui Sag,Qiongdongnan Basin:source-to-sink system,genesis and implication

Deepwater oil and gas exploration is the key to sustainable breakthroughs in petroleum exploration worldwide.The Central Canyon gas field has confirmed the Lingshui Sag is a hydrocarbon-generating sag,and the deepwater reservoirs in the Lingshui Sag still have more fabulous oil and gas exploration potential.Based on drilling data and three-dimensional(3D)seismic data,this paper uses seismic facies analysis,seismic attribute analysis,and coherence slice analysis to identify the types of submarine fans(lobe-shaped and band-shaped submarine fans)that developed in the Lingshui Sag during the Middle Miocene,clarify the source-to-sink system of the submarine fans and discuss the genesis mechanism of the submarine fans.The results show that:(1)the deepwater source-to-sink system of the Lingshui Sag in the Middle Miocene mainly consisted of a“delta(sediment supply)-submarine canyon(sediment transport channel)-submarine fan(deepwater sediment sink)”association;(2)the main factor controlling the formation of the submarine fans developed in the Lingshui Sag was on the relative sea level decline;and(3)the bottom current reworked the lobe-shaped submarine fan that developed in the northern Lingshui Sag and formed the band-shaped submarine fan with a greater sand thickness.This paper aims to provide practical geological knowledge for subsequent petroleum exploration and development in the deepwater area of the Qiongdongnan Basin through a detailed analysis of the Middle Miocene submarine fan sedimentary system developed in the Lingshui Sag.

Genesis and geological significance of carbonate in Changdu Basin,Xizang,China:Constraints from geochemistry and C-O isotopes

Research on the origin of carbonates in Changdu Basin holds significant importance for understanding the regional potash formation model.Based on a comprehensive review of previous studies,field geological surveys,and laboratory investigations,this study analyzes the origin and properties of carbonates within the context of regional potash formation.Petrographic studies show that magnesite deposits,with the characteristics of sedimentary origin.The results of elemental geochemical analysis show that the carbonates in this area were formed in the sedimentary environment via evaporation followed by concentration,and the formation of magnesite was possibly caused by the substitution of calcium in the dolomite with magnesium-rich brine.Theδ^(13)C values of carbonats in the study area are between5.9‰and 9.1‰.Theδ^(18)O values of magnesite samples range from-7.3‰to-1.3‰,and theδ^(18)O values of dolomites range from-10.3‰to-8.4‰.All the calculated Z values of oxygen isotopes of carbonates greater than 120.A comprehensive analysis of carbon and oxygen isotopes indicates that the magnesite was formed in a highly concentrated Marine sedimentary environment and does not show any relation with the metasomatism of hydrothermal fluids.The results on the correlation of magnesite with seawater and its sedimentary origin provide key information for explaining the migration direction of brine between the Changdu and Lanping-Simao Basins.The residual metamorphic seawater in the Changdu Basin migrated to the Lanping-Simao Basin,where potash underwent deposition.Whereas,magnesite and dolomite in the early stage of potash formation were left in the Changdu Basin.

Reactive transport modeling constraints on the complex genesis of a lacustrine dolomite reservoir:A case from the Eocene Qaidam Basin,China

Reactive transport modeling(RTM)is an emerging method used to address geological issues in diagenesis research.However,the extrapolation of RTM results to practical reservoir prediction is not sufficiently understood.This paper presents a case study of the Eocene Qaidam Basin that combines RTM results with petrological and mineralogical evidence.The results show that the Eocene Xiaganchaigou Formation is characterized by mixed siliciclastic-carbonate-evaporite sedimentation in a semiclosed saline lacustrine environment.Periodic evaporation and salinization processes during the syngeneticpenecontemporaneous stage gave rise to the replacive genesis of dolomites and the cyclic enrichment of dolomite in the middle-upper parts of the meter-scale depositional sequences.The successive change in mineral paragenesis from terrigenous clastics to carbonates to evaporites was reconstructed using RTM simulations.Parametric uncertainty analyses further suggest that the evaporation intensity(brine salinity)and particle size of sediments(reactive surface area)were important rate-determining factors in the dolomitization,as shown by the relatively higher reaction rates under conditions of higher brine salinity and fine-grained sediments.Combining the simulation results with measured mineralogical and reservoir physical property data indicates that the preservation of original intergranular pores and the generation of porosity via replacive dolomitization were the major formation mechanisms of the distinctive lacustrine dolomite reservoirs(widespread submicron intercrystalline micropores)in the Eocene Qaidam Basin.The results confirm that RTM can be effectively used in geological studies,can provide a better general understanding of the dolomitizing fluid-rock interactions,and can shed light on the spatiotemporal evolution of mineralogy and porosity during dolomitization and the formation of lacustrine dolomite reservoirs.

The Structure and the Density of a Bare Quark Star in a Cold Genesis Theory of Particles

Based on the preonic structure of quarks obtained in a Cold genesis theory of particles (CGT), it was obtained a semi-empiric relation for the current mass of quarks specific to CGT but with the constants obtained with the aid of the Gell-Mann-Oakes-Renner formula, giving values close to those obtained by the Standard Model, the current quark’s volume at ordinary nuclear temperature being obtained as sum of theoretic apparent volumes of preonic kerneloids. The maximal densities of the current quarks: strange (s), charm (c), bottom (b), and top (t) resulted in the range (0.8 - 4.2) × 1018 kg/m3, as values which could be specific to possible quark stars, in concordance with previous results. By the preonic quark model of CGT, the possible structure of a quark star resulted from the intermediary transforming: Ne(2d+u)→s−¯+λ−and the forming of composite quarks with the structure: C−(λ−-s−¯-λ−) and C+(s−¯-λ−-s−¯), and of Sq-layers: C+C−C+ and C−C+C− which can form composite quarks: Hq±=(SqS¯qSq);(S¯qSqS¯q), corresponding to a constituent mass: M(Hq) = (12,642;12,711) MeV/c2, the forming of heavier quarks inside a quark star resulting as possible in the form: Dq = n3Cq, (n ≥ 3). The Tolman-Oppenheimer limit: MT=0.7M⊙for neutron stars can also be explained by the CGT’s quark model.

Complex genesis of multiperiod fractures in the Middle Triassic Leikoupo Formation in the Pengzhou gas field, western Sichuan Basin, China

The cumulative expression of multistage deformation is complex multiperiod fractures,which are commonly seen in tectonic zones.The Middle Triassic Leikoupo Formation in the western Sichuan Basin Depression,China,is a typical marine carbonate reservoir with natural fractures caused mainly by tectonic movements.According to outcrops,drill cores,image logging,and fluid inclusions,the fracture characteristics,types of natural fractures,and interactions of fractures are determined.In total,419 natural fractures in 493.2 m of cores from 7 wells are investigated,which are mainly shear and tensile fractures with a small number of weathering generated fractures.Meanwhile,the results of the stable isotope analysis of δ13C and δ18O,as well as the flow fluid inclusion data,reveal four tectonic periods of fractures with different occurrences.Based on the history of regional tectonic evolution,indicating one period of weathering fractures ascribable to stratal uplift and three periods of structural fractures related to the sequential tectonic movements of the Longmenshan fault belt.By analyzing the interaction relationships of fractures,three types of fracture interaction relationships are observed:cutting,restraining,and overlapping.The four stages fractures are chronologically assigned to(1)the early Indosinian N-S trending compression,(2)the late Indosinian NW-SE compression,(3)the middle Yanshanian NE-SE compression,and(4)the early Himalayan E-W compression.The influence of natural fractures on gas migration and well production in marine carbonates is discussed,and indicates that tectonic fractures could provide seepage channels for gas migration and accumulation from near or distant hydrocarbon source rocks into the Middle Triassic Leikoupo Formation.This study utilizes a pragmatic approach for understanding the fracture genesis mechanism in oil and gas field with multiperiod fractures.

Genesis, metallogenic model, and prospecting prediction of the Nibao gold deposit in the Guizhou Province, China

Southwestern Guizhou province is one of China’s most important distribution areas of Carlin-type gold deposits. The Nibao deposit is a typical gold deposit in southwestern Guizhou. To elucidate the genesis of the Nibao gold deposit, establish a metallogenic model, and guide prospecting prediction, we systematically collected previously reported geological, geochemical, and dating data and discussed the genesis of the Nibao gold deposit,based on which we proposed the metallogenic model.Earlier works show that the Nibao anticline, F1 fault, and its hanging wall dragged anticline(Erlongqiangbao anticline) were formed before or simultaneously with gold mineralization, while F2, F3, and F4 faults postdate gold mineralization. Regional geophysical data showed extensive low resistivity anomaly areas near the SBT(the product of tectonic slippage and hydrothermal alteration)between the P2/P3 and the strata of the Longtan Formation in the SSE direction of Nibao anticline in the lower plate of F1 and hanging wall dragged anticline(Erlongqiangbao anticline), and the anomaly areas are distributed within the influence range of anticlines. Simultaneously, soil and structural geochemistry show that F1, Nibao anticline,Erlongqiangbao anticline, and their transition areas all show good metallogenic elements(Au, As, and S) assemblage anomalies, with good metallogenic space and prospecting possibilities. There are five main hypotheses about the source of ore-forming fluids and Au in the Nibao gold deposit:(1) related to the Emeishan mantle plume activity;(2) source from the Emeishan basalt;(3) metamorphic fluid mineralization;(4) basin fluid mineralization;(5) related to deep concealed magmatic rocks;of these, the mainstream understanding is the fifth speculation. It is acknowledged that the ore-forming fluids are hydrothermal fluids with medium–low temperature, high pressure, medium–low salinity, low density, low oxygen fugacity, weak acidity, weak reduction, and rich in CO_(2)and CH_(4). The fluid pressure is 2–96.54 MPa, corresponding to depths of 0.23–3.64 km. The dating results show that the metallogenic age is ~141 Ma, the extensional tectonic environment related to the westward subduction of the Pacific Plate. Based on the above explanation, the genetic model related to deep concealed magmatic rocks of the Nibao gold deposit is established, and favorable prospecting areas are outlined;this is of great significance for regional mineral exploration and studying the genesis of gold deposits.

The Relationship Between Indian Ocean SST and Tropical Cyclone Genesis Frequency over North Indian Ocean in May

Tropical cyclone(TC)activities in the North Indian Ocean(NIO)peak in May during the pre-monsoon period,but the TC frequency shows obvious inter-annual variations.By conducting statistical analysis and dynamic diagnosis of long-term data from 1948 to 2016,the relationship between the inter-annual variations of Indian Ocean SST and NIO TC genesis frequency in May is analyzed in this paper.Furthermore,the potential mechanism concerning the effect of SST anomaly on TC frequency is also investigated.The findings are as follows:1)there is a broadly consistent negative correlation between NIO TC frequency in May and SST in the Indian Ocean from March to May,with the key influencing area located in the southwestern Indian Ocean(SWIO);2)the anomalies of SST in SWIO(SWIO-SST)are closely related to a teleconnection pattern surrounding the Indian Ocean,which can significantly modulate the high-level divergence,mid-level vertical motion and other related environmental factors and ultimately influence the formation of TCs over the NIO;3)the increasing trend of SWIO-SST may play an essential role in the downward trend of NIO TC frequency over the past 69 years.

A Scenario for Asymmetric Genesis of Matter

A previous preon scenario for the standard model particles, based on unbroken supersymmetry, is applied to the problem of matter-antimatter asymmetry. Attention is paid to the fact that the asymmetric hydrogen atom—like all atoms—can be described in terms of symmetric preons. Preons are created in the early universe. The matter-antimatter asymmetry is caused by stochastic correlations in charge density fluctuations of preons and antipreons and by the subsequent preon combinatorial mechanism to form quarks and leptons, and finally the three lightest elements. A tentative gravitino mass estimate is given based on minimal interference with nucleosynthesis. With local supersymmetry the scenario can be extended to supergravity.

GENESIS诱导小麦雄性不育与幼穗中乙烯含量的关系

在小麦发育的 Feekes8.5时期用化学杂交剂 GENESIS进行处理 ,分别在小麦花药发育的单核期、二核期和三核期测定幼穗中乙烯释放量的变化 ,研究 GENESIS诱导小麦雄性不育与乙烯的关系。结果表明 :经化学杂交剂 GENESIS诱导后 ,幼穗中乙烯释放量在 3个时期均明显高于对照。随着 GENESIS喷施剂量的增加 ,诱导小麦雄性不育率也相应增加 ,同时幼穗中乙烯释放量也表现出相同的增长趋势。表明 GENESIS诱导小麦雄性不育的生化机理在于 GENESIS诱导小麦幼穗中乙烯释放量增加 ,乙烯释放量的变化与小麦雄性不育有直接关系。同时 ,利用乙烯合成抑制剂 (AVG)处理细胞核质互作雄性不育系后 ,内源乙烯释放速率降低 。

GENESIS诱导小麦雄性不育性与花药组织呼吸关系的初步研究

对小麦小孢子发育的各个时期,经GENESIS处理的和未处理的植株花药的总呼吸活性 Vt 、细胞色素途径呼吸活性 ρ′Vcyt 和交替途径实际呼吸活性 ρValt 进行了比较研究,结果表明,在各时期,处理植株花药的Vt呼吸均低于未处理植株,尤以单核期最为明显;在小孢子减数分裂期、四分体期和单核期,处理小麦植株花药的ρ′Vcyt均明显降低,而在小孢子减数分裂期和四分体期ρValt出现明显升高.结论认为,由呼吸过程中电子传递途径运行的改变而造成处理植株花药呼吸代谢的紊乱,可能是GENESIS诱导小麦雄性不育发生的重要原因.

化学杂交剂GENESIS对小麦的杀雄效果

采用 4个品种 ,4个剂量 ,2个表面活性剂的裂区试验和 2个品种的异地试验 ,对新型化学杂交剂GENESIS诱导小麦雄性不育的效果进行了研究。结果表明 :( 1)GENESIS杀雄彻底 ,2 0kg/hm2 以上剂量的不育率均超过 95 % ,3 0、 5 0kg/hm2 剂量达到或接近 10 0 % ,且没有诱导小麦雄性不育的专一性 ;( 2 )不育率为 95 %以上的人工饱和授粉结实率和自然授粉结实率最高达 6 7 6 5 %和 49 83% ;( 3) 5 0kg/hm2 剂量下 ,添加表面活性剂MON816 1的人工饱和授粉结实率比添加MON5 916 0的降低 18 9% ,差异显著。说明表面活性剂MON816 1对雌蕊的活力具有一定影响 ;( 4)相同基因型在两个地点的不育率和自然授粉结实率差异不显著 。

化学杂交剂GENESIS对小麦生长发育的影响

为了评价化学杂交剂GENESIS的副效应,研究了GENESIS对普通小麦的农艺性状、倒二叶叶片叶绿素含量和雌蕊育性的影响,结果表明:GENESIS对小麦的生长有一定的抑制作用,主要表现在株高降低,抽穗期和开花期延迟1￣2d,株高的降低主要是由穗下第一节间缩短造成的,3个剂量处理间株高的差异未达到显著水平;GENESIS对小麦倒二叶叶片叶绿素含量有一定程度的影响,叶片能自我修复,但剂量越大、喷施时期越晚,叶片的损伤越大,其修复能力越差;GENESIS对雌蕊育性几乎没有影响。

GENESIS诱导小麦雄性不育活性窗口研究

在小麦大小分蘖达到适宜喷药期 ,而部分主茎 (大约 1%左右 )已经超过 Feeks9.0的情况下 ,为了检测GENESIS是否能有效地抑制这类主茎的自交结实 ,选择了 2 0个优势群亲本基因型小麦品种 (系 )进行了试验。结果表明 ,当小麦生长时期处于 Feeks9.0～ 9.8时 ,进行一次叶面喷施 ,所有参试品种仍可达到 95 %以上的杀雄效果 ,能够有效地抑制小麦自交结实 ,同时对其中 10个参试小麦品种进行人工饱和授粉 ,证明 GENESIS对雌蕊的育性没有明显影响。

化学杂交剂GENESIS对小麦生长发育的影响

采用 8个基因型 ,4个剂量的裂区试验 ,对新型化学杂交剂GENESIS完全诱导小麦雄性不育时的人工饱和授粉结实率、农艺性状表现、种子发芽势和发芽率进行了比较研究。结果表明 :3.0kg/hm2 、5 .0kg/hm2 剂量的雄性不育率达到或接近 10 0 %时 ,人工饱和授粉最高结实率分别为 84 .72 %、6 6 .71% ,前者超对照 11.13% ,后者与对照相近 ,但较 3.0kg/hm2 减少 11.4 8%。GENESIS对小麦抽穗期和株高没有不良效应 ;5 .0kg/hm2 时千粒重较对照减少1.1g;籽粒的发芽势、发芽率和产量明显低于对照 。

化学杂交剂GENESIS诱导普通小麦雄性不育效果研究

以 2 0个普通小麦品种为母本 ,采用二裂式裂区设计 ,研究了化学杂交剂 Genesis的诱导雄性不育效果和不同品种间的遗传差异 ,结果表明 :1) Genesis对普通小麦有良好的诱导雄性不育效果 ,供试的 2 0个品种的不育率为 99.2 %～ 10 0 % ,杂交率为 83%～ 10 0 % ,反应度为 2～ 7级 ;2 )不同施用剂量间的杀雄效果存在显著差异 ,以 3kg/hm2 的剂量最优 ,其不育率近 10 0 % ;3)不同喷药时期 (Feeke` s stage8.0和 9.0 )间差异不显著 ,适喷期 7d左右。根据试验结果 ,还讨论了 Genesis的药害问题与适喷期小麦发育的形态指标。

基于GENESIS64的架桥机3D远程监控系统

介绍了一种基于组态软件GENESIS64创建的架桥机3D远程监控系统,该系统具备监控架桥机工作过程和指定运行参数能力,能够对重要的运行参数和安全状态进行记录并管理,并实时显示架桥机报警信息。结合GENESIS64独特的3D可视化及WIN7显示技术,通过现场数据实时驱动架桥机3D模型运动,实现了起重设备3D远程虚拟监控。

中置型GenesisⅡ人工膝关节置换近期疗效报道

目的 报道应用GenesisⅡ假体进行全膝置换的近期疗效及其技术特点。方法 2 0 0 3年 6～ 9月 ,采用GenesisⅡ骨水泥人工假体对 2 8例 32膝行膝关节置换术。原发性膝骨关节炎 2 4膝、类风湿性关节炎 4膝、创伤性关节炎 3膝和痛风性关节炎 1膝。 17例 18膝应用CR假体 ;11例 14膝应用PS假体。 13例 15膝行髌骨表面置换术 ,其中 10膝采用嵌入式髌骨固定技术。结果 采用纽约特种外科膝关节评分 (HSS)法评估临床疗效 ,术前平均为 4 3分 ,术后 4周和 12周分别为 86和 92分 ;4周时优良 2 5膝 ,可 7膝 ;12周时优良 2 8膝 ,可4膝。术前平均膝关节屈伸活动度为 86° ,术后 4周和 12周分别为 115°和 12 0°。术后 2周内有轻度深静脉栓塞5例 ,所有患者均未出现早期感染、脱位等并发症。结论 近期疗效显示 ,GenesisⅡ膝关节假体因股骨后髁的不对称设计 ,安置时仅需中立位截骨 ,无需外旋 ,可有效避免放置后旋转对线不良 ;滑车沟为解剖型 ,活动时髌股完全接触 ,术后膝前痛明显改善。远期疗效尚需进一步观察。

化学杀雄剂GENESIS诱导早熟禾雄性不育的初步研究

试用美国新近生产的化学杀雄剂 GENESIS对早熟禾进行雄性不育的初步研究。结果表明 ,参试的 4个品种瓦巴斯草地早熟禾、思托佩草地早熟禾、天祝扁秆早熟禾与莫诺波利草地早熟禾在生育期 Feekes标准 8.0～ 9.0时 ,用 GENESIS进行一次叶面喷施 ,在 1. 5kg/ hm2 和 2 .5kg/ hm2 的剂量下 ,天祝扁秆早熟禾的杀雄效果为 95%和 97% ,其它品种均为10 0 %