四川盆地广安地区中二叠统栖霞组岩石特征与沉积环境

四川盆地中二叠统栖霞组勘探发现系列油气，资源潜力巨大。但广安地区中二叠统栖霞组的岩石学特征及沉积环境研究薄弱。在野外地质调查的基础上，结合室内岩石学、岩相学等综合分析，对广安地区栖霞组碳酸盐岩岩石特征、沉积相类型及其古地理展布特征进行了系统研究。结果表明：广安地区栖霞组主要发育亮晶颗粒灰岩、亮晶生物碎屑灰岩、微晶生物碎屑灰岩、微晶颗粒灰岩、生物碎屑微晶灰岩、含生物碎屑微晶灰岩和泥晶灰岩7种岩石类型；碳酸盐岩颗粒主要以生物碎屑为主，部分层位发育球粒；古生物化石以三叶虫、腕足和有孔虫为主，同时可见棘皮类和藻类；栖霞组沉积期主要为碳酸盐岩台地沉积环境，其中栖霞组晚期（栖二段）台缘滩和台内滩较为发育，为该区油气成藏提供了有利条件。     

帕米尔高原Rushan-Pshart古特提斯洋或中特提斯洋争论的岩石地球化学证据

帕米尔高原上广泛分布的加里东期火山岩,印支期火山岩与燕山期火山岩被认为是块体依次向北俯冲拼贴到欧亚板块上的产物。特别是燕山期火山岩被认为是Rushan-Pshart中特提斯洋闭合的产物。但近年来地层古生物、火山岩证据不断表明Rushan-Pshart洋闭合时间在晚三叠一早侏罗世,由此限定Rushan-Pshart古特提斯洋性质,而帕米尔高原上广泛分布的燕山期火山岩是更南部的Shyok中特提斯洋闭合的产物。目前,中国境内Rushan-Pshart缝合带属性的研究工作展开较晚,研究程度较低。我们对塔什库尔干明铁盖沟一线燕山期火山岩带展开的工作发现零星分布的印支期花岗岩。印支期花岗岩错石U・Pb年龄显示岩体侵位时间在201 Ma左右。全岩主量元素特征表明岩石为I型高钾钙碱性闪长花岗岩;稀土元素在球粒陨石标准化图解中呈轻稀土元素相对富集,重稀土元素相对亏损的右倾海鸥型。明铁盖岩体的微量元素显示大离子亲石元素明显富集,而高场强元素明显亏损。稀土微量元素特征倾向花岗岩属性为岛弧型花岗岩,Sr-Nd-Hf同位素比值特征显示岩体形成于下地壳部分熔融环境。岩体的地化特征表明岩体形成的构造环境为板块汇聚的洋壳俯冲阶段,结合区域地质特征,我们将花岗岩体归为Rushan-Pshart古特提斯洋壳俯冲消减的产物。Rushan-Pshart缝合带传统上认为是中特提斯带,近年的研究进展认为其为古特提斯缝合带,本文的工作支持这种观点。Rushan-Pshart古特提斯缝合带的确立对帕米尔高原与青藏高原主体的块体对比提供了可信的对比方案,并对青藏高原新生代陆内变形方式的争论提供了可靠的证据。     

A Revisited Purification of Li for ‘Na Breakthrough’ and its Isotopic Determination by MC‐ICP‐MS

The accurate and precise determination of Li isotopic composition by MC‐ICP‐MS suffers from the poor performance of traditional column chromatography. Previously established chromatographic processes cannot completely remove Na in complex geological samples, which is currently interpreted to be a result of Na breakthrough. In this study, Na breakthrough during single‐column purification was found to differ between simply artificial Na‐containing sample solutions, where a little Na residue was found, and silicate rocks, where a large amount of breakthrough occurred. A revised two‐step column purification for Li using 0.5 and 0.3 mol l^?1 HCl as eluents was designed to remove the Na. This modified method achieves high‐efficiency Li purification from Na and consequently avoiding high Na/Li ratio interference for subsequent MC‐ICP‐MS analyses. The proposed method was validated by the analysis of a series of reference materials, including Li₂CO₃ (IRMM‐016, ‐0.10‰), basalt (BCR‐2: 2.68‰; BHVO‐2: 4.39‰), andesite (AGV‐2: 6.46‰; RGM‐2: 2.59‰), granodiorite (GSP‐2: ?0.87‰) and seawater (CASS‐5, 30.88‰). This work reports early Na appearance prior to the elution curves in chromatography and emphasises its influence for subsequent Li isotope measurement. Based on the findings, the established two‐step method would be more secure than single‐column chemistry for Li purification.     

Petrogenesis of Early Cretaceous hornblende gabbro in Khanka Massif: evidence from geochronology and geochemistry

The authors report zircon U-Pb geochronological,whole-rock geochemical and zircon Lu-Hf isotope data for the hornblende gabbro within the Khanka Massif,with the aim of constraining its formation time and petrogenesis. The zircon U-Pb dating shows that ~(206)Pb/~(238)Pb ages of zircons from the hornblende gabbro range from 120 to 129 Ma,yielding a weighted mean age of 123 ± 2 Ma,i. e.,the Early Cretaceous. The hornblende gabbro has SiO_2 of 44. 77%--46. 58% and belongs to the tholeiitic series on FeO~t/MgO-SiO_2 diagram. It displays a right-inclined REE pattern with( La/Yb)_N ratios of 3. 44 to 4. 42. The trace element spidergram shows that they are enriched in large ion lithophile elements( LILE) such as Rb,Th,U,K and Pb,and depleted in high field strength elements( HFSE) such as Nb,Ta,Ti and P,indicating an affinity to arc igneous rocks.The ε_(Hf)( t) values of zircons vary from -2. 6 to + 3. 9 and Hf model ages( T_(DM1)) range from 622 to 883 Ma.These geochemical characteristics indicate that primary magma of the hornblende gabbro could be derived from partial melting of young mantle material accreted during the Neoproterozoic. Combined with the Early Cretaceous igneous rock assemblages in NE Asia. It is concluded that the hornblende gabbro formed in an active continental margin related to the westward subduction of the Paleo-Pacific Plate beneath the Khanka Massif.     

Explicit stress–strain equations for modeling frictional materials

In this paper, a comprehensive study on simulating the shearing behavior of frictional materials is performed. A set of two explicit equations, describing the relationship among the shear stress ratio and the distortional strain and the volumetric strain, are formulated independently. The equations contain three stress parameters and three strain parameters and another parameter representing the nonuniformity of stress and strain during softening. All the parameters have clear physical significance and can be determined experimentally. It is demonstrated that the proposed equations have the capacity of simulating the complicated shearing behavior of many types of frictional materials including geomaterials. The proposed equations are used to simulate the stress–strain behavior for 27 frictional materials with 98 tests. These materials include soft and stiff clays in both reconstituted and structured states, silicon sands and calcareous sands, silts, compacted fill materials, volcanic soils, decomposed granite soils, cemented soils (both artificially and naturally cemented), partially saturated soils, ballast, rocks, reinforced soils, tire chips, sugar, wheat, and rapeseed. It has been demonstrated that the proposed explicit constitutive equations have the capacity to capture accurately the shearing behavior of frictional materials both qualitatively and quantitatively. A study on model parameters has been performed.     

泉水流量、电导率、pH值动态变化研究

岩溶水是指赋存于岩溶孔隙中的地下水，是我国南方生产生活主要用水来源.随着社会对水资源需求的逐步扩大，岩溶水资源的开发利用越发重要.通过定期监测岳麓山泉水流量、电导率、pH值，结合岳麓山岩土层性质和长沙市降雨量，采用统计分析和Spearman秩相关系数法对泉水流量变化和泉水水质定性评价进行研究.研究结果表明，大气降雨对岩溶水进行补给从而使泉水流量增大，泉水流量的改变除与降雨量有关外，还受土壤入渗率和降雨时长的影响.采用Spearman秩相关系数法可定量计算电导率与时间的相关性，间接判断周围环境对泉水水质影响的难易程度，有利于识别电导率代表性位置泉眼，更好地监测和评价岩溶水.土壤酸沉降污染严重或酸雨频繁地区易导致岩溶水pH值呈酸性.对泉水流量和水质的研究有利于科学开发利用岩溶水资源.     

Effects of stocking density on the growth and immunity of Atlantic salmon salmo salar reared in recirculating aquaculture system (RAS)

Atlantic salmon reared in recirculating aquaculture system (RAS) may lead to inappropriately high stocking density, because fish live in a limited space. Finding the suitable stocking density of Atlantic salmon reared in RAS is very important for RAS industry. In this paper, the influence of stocking density on growth and some stress related physiological factors were investigated to evaluate the effects of stocking density. The fish were reared for 220 days at five densities (A: 24 kg/m³; B: 21 kg/m³; C: 15 kg/m³; D: 9 kg/ m³ and E: 6 kg/m³ ). The results show that 30 kg/m³ might be the maximum density which RAS can afford in China. The stocking densities under 30 kg/m³ have no effect on mortality of Atlantic salmon reared in RAS. However, the specific growth rate (SGR), final weight and weight gain in the high density group were significantly lower than the lower density groups and middle density groups. Moreover, feed conversion rate (FCR) had a negative correlation with density. Plasma hormone T₃ and GH showed significant decrease with the increase of the stocking density of the experiment. Furthermore, thyroid hormone (T₃), GH (growth hormone) activities were decreased with stocking density increase. However, plasma cortisol, GOT (glutamic oxalacetic transaminase) and GPT (glutamic pyruvic transaminase) activities were increase with stocking density increase. And the stocking density has no effects on plasma lysozyme of Atlantic salmon reared in RAS. These investigations would also help devise efficient ways to rear adult Atlantic salmon in China and may, in a way, help spread salmon mariculture in China.

     

邮轮属性评价与品牌定位

以全球最大的邮轮点评网站——邮轮评论家为数据来源渠道，以编辑（Editor/Expert）的文本点评以及对167艘邮轮10大属性的打分数据为样本，利用词频分析、回归分析、聚类分析和方差分析等方法，对全球21个邮轮品牌的产品属性、总体评价以及品牌定位问题进行了系统研究。结果表明，对于专业型游客来说，餐饮、客房和娱乐是关注度最高的船上属性，服务、性价比和公共空间是满意度最高的船上属性，客房、餐饮、公共空间、性价比和娱乐属性对邮轮总评具有显著影响。方差分析表明，与行业界定下的品牌行为相比，基于专业型游客感知的品牌划分更有效。     

A case study on Landscape Component Niche based on Landscape Pattern Indices: Yanchi,Ningxia Province,China

Yanchi County is located in the agro-pastoral ecotone and belongs to the ecologically fragile area of Northwest China.It is important to study the evolution of landscape pattern to curb its environmental degradation.In order to intuitively show how the landscape pattern of the study area changes over time,Landsat Thematic Mappers(TM)and Landsat Operational Land Imager(OLI)data of 1991,2000,2010 and 2017 were used.This paper attempts to apply niche theories and methods into landscape ecology,and constructs a niche model of landscape components by using"n-dimentional hypervolume niche theory"and landscape pattern indices.By evaluating the spatial and temporal evolution of niche from the perspective of two-dimensional space to reflect the changes of landscape pattern in the study area over the past 26 years,new theories and methods were introduced for the characterization of landscape pattern.The results indicate that:1)The larger the attribute and dominance value of landscape components,the higher the ecological niche and the stronger the control effect on the overall landscape.2)The ecological niche of each landscape component was significantly different,just as its control effect on the overall landscape.3)The dynamic change of the ecological niche of each landscape component was different,with grassland,unused land and arable land always in a high dominant position,although the ecological niche of construction land and water area was always low.In general,the introduction of niche theory into the landscape ecology provided a new method to study the changes in regional landscape pattern.     

Discovery of 13 New Variable Stars in the Field of the Open Cluster NGC 2168 （M35）

A wide-field time-series CCD photometric survey of variable stars in the field of the open cluster NGC 2168 was carried out using the BATC Schmidt telescope. In total 13 new variable stars are discovered with three W UMa systems, one EA type and two EB type eclipsing binaries (one of them could be a W UMa system), and seven pulsating stars including three candidates of δScuti stars.