The proto-terrestrial mechanism of the appearance of water and early genesis of the global ocean

We consider chemical reactions for the appearance of water during the formation of the planet from cosmic gas and dust material to explain the early geological existence of the Earth’s hydrosphere. This process is fully supported by the resources of the initial substances and thermal energy. Thus, the concept of V.I. Vernadsly about the geological eternity of the World Ocean and ancient age of the oceanic lithosphere is supported. The identical high location of the ancient and modern continental platforms under the conditions of continual isostatical equilibrium in the asthenosphere–lithosphere–hydrosphere gives grounds to conclude that the ocean water depth is stable. Taking this into account, we can consider that the geological evolution of the Earth began in the conditions of the existence of the World Ocean when the mass of the hydrosphere only slightly exceeded the modern one.     

Application of 2D numerical model to unsteady performance evaluation of vertical-axis tidal current turbine

Tidal current energy is renewable and sustainable, which is a promising alternative energy resource for the future electricity supply. The straight-bladed vertical-axis turbine is regarded as a useful tool to capture the tidal current energy especially under low-speed conditions. A 2D unsteady numerical model based on Ansys-Fluent 12.0 is established to conduct the numerical simulation, which is validated by the corresponding experimental data. For the unsteady calculations, the SST model, 2×10~5 and 0.01 s are selected as the proper turbulence model, mesh number, and time step, respectively. Detailed contours of the velocity distributions around the rotor blade foils have been provided for a flow field analysis. The tip speed ratio(TSR) determines the azimuth angle of the appearance of the torque peak, which occurs once for a blade in a single revolution. It is also found that simply increasing the incident flow velocity could not improve the turbine performance accordingly. The peaks of the averaged power and torque coefficients appear at TSRs of 2.1 and 1.8, respectively. Furthermore, several shapes of the duct augmentation are proposed to improve the turbine performance by contracting the flow path gradually from the open mouth of the duct to the rotor. The duct augmentation can significantly enhance the power and torque output. Furthermore, the elliptic shape enables the best performance of the turbine. The numerical results prove the capability of the present 2D model for the unsteady hydrodynamics and an operating performance analysis of the vertical tidal stream turbine.     

深海细菌太平洋火色杆菌中α-淀粉酶基因amy608的克隆表达及其酶学性质研究

从来自深海沉积物的太平洋火色杆菌(Flammeovirga pacifica)的基因组中发现了一个全长为1 875 bp的α-淀粉酶基因amy608.该基因在数据库中找不到具有同源性的序列,而所编码的Amy608蛋白与已注册蛋白的氨基酸序列相似性最高仅为56%,但具有α-淀粉酶水解活性所必需的保守基序DXEXD.进化树分析表明其属于糖苷水解酶13(GH13)家族第二亚家族.构建了p ColdΙ-amy608表达载体,在大肠杆菌中进行重组Amy608蛋白的异源表达,并采用镍离子亲和层析柱对重组蛋白进行了纯化.酶学性质分析表明,重组酶Amy608的最适作用温度为40℃,在40℃保温4 d后,仍保留70%以上的酶活,显示出良好的中温热稳定性;最适p H值为7.0,p H值范围在6~9时仍保留60%以上的酶活力,表明该酶具有较宽的p H值作用范围.Ca2+、Na+、K+对α-淀粉酶Amy608有激活作用,尤其是Ca2+可使酶活显著提高40%.薄层色谱分析结果显示该酶水解可溶性淀粉的最终产物以葡萄糖为主,表明该酶是一个糖化型淀粉水解内切酶.这些结果表明Amy608为GH13家族第二亚家族中一个新型的α-淀粉酶.     

Studies of Particulate Matter Distribution by Aqua Modis Data and Simulation Results

Doklady Earth Sciences - Ways of combined usage of data obtained by the satellite sounding of the marine surface along with modeling approaches are considered. The technique of data application is...     

The Magmatic–Hydrothermal Transition and Origin of Brine in the Oceanic Core Complex of the Mid-Atlantic Ridge at 13° N

New data on local mineral associations and the microheterogeneity of minerals and fluid inclusions in gabbro were obtained for the gabbro–peridotite oceanic core complex with a long-lived detachment fault controlling the hydrothermal activity. It is assumed that the hydrothermal hydrogen-bearing fluid with a NaCl content of >30 wt % is formed in the seawater/harzburgite (~1/5) reaction of serpentinization. The brine residual after serpentinization interacted with gabbro at the final stages of crystallization of an intrusion and assimilated some components (K, REEs, and Ba) from the residual melt. The interaction was resulted in metamorphic transformations of gabbro at decreasing temperature below 500°C. The reaction of the decomposition of magmatic titanomagnetite with the transition of iron reduced to Fe²⁺ into newly formed chlorinebearing amphibole at 540–450°C and logf(O₂) from–20 to–24 is shown.

     

Petrogenesis of the Late Cenozoic collision volcanism in the central part of the Lesser Caucasus (Azerbaijan)

The Late Cenozoic volcanics of the Lesser Caucasus have similar trace-element and REE patterns with negative anomalies of Nb, Ta, Hf, and Zr. They are highly enriched in Rb, Ba, Th, and La and depleted in Ti, Yb, and Y with respect to N-MORB, which indicates their formation from the subduction-metasomatized lithospheric mantle. Partial melting of the subcontinental mantle lithosphere and crustal assimilation and fractional crystallization controlled the magma evolution in the collisional magmatic belts.     

Epifanovite,NaCaCu5(PO4)4[AsO2(OH)2] · 7H2O: a New Mineral from the Kester Deposit,Sakha (Yakutia) Republic,Russia

Geology of Ore Deposits - Epifanovite, NaCaCu5(PO4)4[AsO2(OH)2] · 7H2O, a new natural copper, sodium and calcium arsenate–phosphate, has been found in a quartz–phosphate pocket...     

西秦岭温泉—中川一带金属矿床的成矿规律及找矿预测

西秦岭温泉—中川一带实施的1:5万矿产地质调查项目,共圈定1:5万局部高磁异常33处,1:5万地球化学综合异常11处,发现矿点2处,矿化点5处,矿种有金、钼、铁、铜、铷等。通过分析研究区成矿地质条件、1:5万地球物理和地球化学综合异常特征、矿(化)点特征及分布规律等,阐明了该区成矿时空分布规律和矿产共生组合规律,划分成矿远景区9处,提交找矿靶区6处。对其中2处找矿靶区进行槽探验证的结果为: 关子镇幅玉杨观找矿靶区圈定了4条含铷矿化伟晶岩脉和多处铁矿化破碎蚀变带,具有形成伟晶岩型铷矿的潜力; 礼县幅李坝金矿床南侧百叶沟—河西沟找矿靶区圈定了14条蚀变破碎带,在矿化蚀变带内圈定了11条金矿(化)体,具有形成构造蚀变岩(微细粒浸染状)型金矿床的潜力。