A new analytical solution of tidal water table fluctuations in a coastal unconfined aquifer

This paper presents a new perturbation solution of the non-linear Boussinesq equation for one-dimensional tidal groundwater flow in a coastal unconfined aquifer. Built upon the work of Parlange et al. [Parlange, J.-Y., Stagnitti, F., Starr, J.L., Braddock, R.D., 1984. Free-surface flow in porous media and periodic solution of the shallow-flow approximation, J. Hydrol., 70, 251–263], the solution adopts a new perturbation parameter that is by definition less than unit, and thus is applicable to a wider range of physical conditions within the constraint of the Boussinesq approximation. This approach avoids a secular term in the third-order perturbation equation of Parlange et al. (1984), enabling the derivation of the third- and higher-order solutions. In comparison with a numerical (“exact”) solution, the new perturbation solution is shown to be slightly more accurate than that of Parlange et al. (1984) with the second-order approximation. The obtained third-order solution exhibits considerable improvement in accuracy. In relatively simple analytical forms, the present perturbation solution will help to understand better the non-linear characteristics of tidal water table fluctuations in as modeled by the non-linear Boussinesq equation coastal unconfined aquifers.     

云南阳宗海表层沉积物有机质组成结构对磷赋存形态特征的影响

利用连续提取分级的方法定量分析阳宗海表层沉积物磷赋存形态,阐明了沉积物C、N、H和O组成及溶解有机质(DOM)紫外-可见光谱特征,探讨沉积物元素组成及DOM组成结构对不同形态磷含量的影响.结果表明:(1)沉积物潜在可移动磷含量在68.67~124.70 mg/kg之间变化,平均占总磷含量的9.81%,表现为BD-PNa OH-nr PNH_4Cl-P;沉积物稳定磷含量在496.73~908.28 mg/kg之间变化,平均占总磷含量的60.86%.(2)沉积物C、N含量和疏水性DOM光谱参数A_(240-400)表现出北部高、南部低的变化趋势,但H/C、O/C和(N+O)/C摩尔比和亲水性DOM光谱参数A_(240-400)变化趋势则与之恰好相反.(3)沉积物NH4Cl-P含量与C、N和H含量之间呈显著正相关,但与H/C、O/C、(N+O)/C摩尔比和亲水性DOM光谱参数E_2/E_3值之间呈显著负相关;NaOH-rP和BD-P+NaOH-rP含量均与O含量及O/H摩尔比呈显著负相关;NaOH-rP、BD-P+NaOH-rP和HCl-P均与疏水性DOM光谱参数A_(240-400)值之间呈显著正相关.因此,天然有机质元素组成及官能团结构是影响沉积物磷赋存形态的重要因素.     

Analysis of types and changes of village-level economy in rural Gongyi city,Henan Province since 1990

Based on the research on the rural living standard in China in terms of annual net income per capita, we define six types of village-level economy, i.e. ＂to be extremely poor＂, ＂to make a basic living＂, ＂to dress warmly and eat one＇s fill＂, ＂to try to enrich （to disengage poverty）＂, ＂to be well-off＂ and ＂to be affluent＂. The data of average annual net income of all the 292 villages between 1990 and 2004 in rural Gongyi City, Henan Province were collected, verified and classified. By using standard deviation, coefficient of variation and regression analysis, it is found that the Gongyi＇s rural economy has boosted up remarkably from the relative-poverty and absolute-poverty stages in 1990 to the well-off in 2004. However, the absolute differences between villages present a trend of enlargement, while the relative differences fluctuating. On the other hand, spatial analysis of village-level economy shows that most villages with relatively high economic development level were located along national expressway and most villages with absolute-poverty lay in remote mountainous areas in 1990. Since the 1990s, the rapid urbanization and industrialization have had strongly positive effects on rural economic growth. Initial economic foundation, natural resources and traditional techniques also contribute to village economy. From the perspective of geography, villages with location advantages, such as near urban center or industrial parks, have more chances for their economic development and the ＂core-periphery＂ economic structure has been presented in the process of rural development.     

煤岩的显微构造特征及其与瓦斯突出的关系——以南桐鱼田堡煤矿为例

煤瓦斯突出与煤岩显微结构构造密切相关。除部分显微结构构造与成煤阶段的环境等有关外,大部分都是构造变形的结果。因此,我们从构造变形类型和特点来划分煤岩显徽构造类型,既简便又利于应用。根据四川南桐鱼田堡煤矿4号及6号煤层的扫描电子显微镜研究,可将煤岩划分成5类:非构造煤、微裂隙煤、微劈理煤、碎裂构造煤和糜棱构造煤。文中详述了各类煤的特点,指出它们所代表的构造意义,并讨论了它们与瓦斯突出的关系。还特别提出糜棱构造煤的一系列塑性变形特征。得出结论:若其他条件均具备,有糜棱构造煤产出的地段,就可能是瓦斯突出最危险的部位。此外,根据观察煤瓦斯突出后的煤岩显微构造变化,提出有关瓦斯突出的过程,并探讨了煤瓦斯突出机理。在瓦斯突出过程中,已经历过塑性变形的煤岩又叠加了脆性变形,因而发生大量煤“粉尘”随突出而抛出。     

基于“DEM-NDVI-土地覆盖分类”的天山博格达自然遗产地山地垂直带提取与变化分析

本文基于Landsat影像数据获取天山博格达自然遗产地土地覆盖分类,结合归一化植被指数（NDVI）和数字高程模型（DEM）构建“DEM-NDVI-土地覆盖分类”散点图分析研究区植被受海拔和坡向的水热空间变化影响的分布特征,通过概率统计分析提取博格达遗产地山地垂直带,并结合研究区的气温、降水数据和NDVI变化特征分析垂直带变化的原因。研究结果表明：① 本文利用“DEM-NDVI-土地覆盖分类”散点图,揭示了研究区1989年和2016年的NDVI值和分类类别随着海拔上升的变化特征,其中NDVI值随着海拔上升呈现“倒U形”变化,而不同分类类别在一定的海拔区间内呈现出聚集效应,且不同分类类别有明显的高程界限。② 1989年和2016年博格达遗产地山地垂直带分带上限分别为：1278 m和1185 m（温带荒漠草原带）、1784 m和1759 m（山地草原带）、2706 m和2730 m（山地针叶林带）、3272 m和3293 m（高山草甸带）、3636 m和3690 m（高山垫状植被带）。③ 博格达遗产地1989年和2016年山地垂直带受区域气温升高和降雨增加的影响有较为明显的改变,其中温带荒漠草原带最为敏感,其上限变化最大,向下收缩93 m;山地针叶林带的分布范围则向两侧扩张49 m;山地草甸带带宽基本保持不变,但整体上移了约20 m;冰雪带则受到全球气候变暖的影响向上退缩54 m。     

被动陆缘盆地陆隆斜坡对盐构造形成的影响 ——来自物理模拟实验的启示

被动陆缘盆地盐构造形成的影响因素及时空演化分析受到了国内外学者的高度重视.丰富的油气资源促进了被动陆缘盆地地震资料品质的不断提升,高精度地震数据的解译结果表明,被动陆缘盆地盐层下的地形往往具有大型的起伏特征,而前人在基底构造形态对盐构造形成影响方面的研究并未取得共识,仍需要深入研究和探讨.为此,本文基于前人的研究认识,...     

中国古代牧业社会骨制品的初步考察:以新疆巴里坤石人子沟遗址为例

考古遗址出土骨制品的研究对于揭示古代社会的动物资源获取和利用、手工业生产、社会组织结构等问题具有重要意义。国内骨制品研究目前多集中在农业区域,这些研究为探讨新石器时代至青铜时代的动物使用及其与社会发展、早期国家形成的关系等问题作出了重要贡献。然而,针对牧业社会骨制品的考察十分缺乏。新疆哈密地区巴里坤草原分布有大量古代牧业文化遗址,石人子沟遗址（43°31'12.8"~43°34'28.9"N,93°13'44.8"~93°16'49.1"E）是其中一处青铜时代晚期至铁器时代早期的大型聚落。本文从动物考古学视角研究该遗址2006年至2011年发掘出土的426件骨制品。结果显示,石人子沟遗址骨制品的原料主要为以羊（Ovis aries/Capra hircus）、马（Equus caballus）为主的家养动物和以鹿（Cervidae）为主的野生动物,其中羊的比例最高（69.7%）,鹿（13.8%）、马（2.3%）次之,这与中原地区青铜时代农业文化遗址的骨制品多以牛为原料的情况明显不同。羊在骨制品原料中占绝对多数且大量使用羊距骨制品的现象是对石人子沟遗址以牧业为主的生业经济方式的直接反映。石人子沟遗址不同类型骨制品的制作各具特点,但整体表现出"省时省力"的特点,即对使用部位细致打磨,对非使用部位仅做简单处理。与中原地区商周时期大型制骨作坊规范化、规模化、产业化的骨器生产不同,石人子沟遗址未见专门的制骨场所,骨制品生产的操作链条也并不完整。遗址的骨制品生产可能是以家庭为单元进行的,产品的专业化、精细化程度也相对较低。该研究填补了我国古代牧业文化遗址出土骨制品动物考古学专门研究的空白,为进一步探究我国古代不同区域、不同生业经济基础下的制骨手工业面貌提供了重要资料。

     

鄂尔多斯西南缘前陆盆地沉降和沉积过程模拟

本文将东祁东逆冲带与鄂尔多斯西南缘晚三叠世前陆盆地相结合，研究了逆冲带内部变形特征，前陆盆地中层序地层格架特征及其反映的盆缘构造性质和幕式逆作作用。     

Mineralogical, chemical, and crystallographic properties of supergene jarosite-group minerals from the Xitieshan Pb-Zn sulfide deposit, northern Tibetan Plateau, China

Supergene jarosite-group minerals are widespread in weathering profiles overlying Pb-Zn sulfide ores at Xitieshan, northern Tibetan Plateau, China. They consist predominantly of K-deficient natrojarosite, with lesser amounts of K-rich natrojarosite and plumbojarosite. Electron microprobe (EMP) analyses, scanning electron microcopy (SEM) investigation, and X-ray mapping reveal that the jarosite-group minerals are characterized by spectacular oscillatory zoning composed of alternating growth bands of K-deficient and K-bearing natrojarosite (K₂O >1 wt.%). Plumbojarosite, whenever present, occurs as an overgrowth in the outermost bands, and its composition can be best represented by K_0.29Na_0.19Pb_0.31Fe_2.66Al_0.22(SO₄)_1.65(PO₄)_0.31(AsO₄)_0.04(OH)_7.37. The substitution of monovalent for divalent cations at the A site of plumbojarosite is charge balanced by the substitution of five-valent for six-valent anions in XO₄ at the X site. Thermogravimetric analysis (TGA) of representative samples reveal mass losses of 11.46 wt.% at 446.6 °C and 21.42 wt.% at 683.4 °C due to dehydroxylation and desulfidation, respectively. TGA data also indicate that the natrojarosite structure collapses at 446.6 °C, resulting in the formation of NaFe(SO₄)₂ and minor hematite. The decomposition products of NaFe(SO₄)₂ are hematite and Na₂SO₄. Powder X-ray diffraction (XRD) analyses show that the jarosite-group minerals have mean unit-cell parameters of a?=?7.315 Å and c?=?016.598 Å. XRD and EMP data support the view that substitutions of Na for K in the A site and full Fe occupancy in the B site can considerably decrease the unit-cell parameter c, but only slightly increase a. The results from this study suggest that the observed oscillatory zoning of jarosite-group minerals at Xitieshan resulted mainly from substitutions of K for Na at the A site and P for S at the X site.     

Study of Influence of Regional Geodynamic Background on Strata Behaviors in China's Tongxin Mine

Strata behaviors are mainly affected by regional geodynamic background. The influence of rock mass stress and energy distribution on strata behaviors in the Tongxin mine is studied in terms of regional tectonic movement, seismic activity and tectonic stress field. The results show that the extrusion lifting movement of Kouquan fault adjacent to the Tongxin mine results in the stress concentration in the rock of the Carboniferous coal bed and accumulation of a large amount of elastic energy and forms structural background of Tongxin mine. Due to various seismic activities in the mine area, the strain energy is known to reach much higher levels, up to 0.5×10⁸ J^1/2. Since the stratigraphic structure is sensitive to the mining operation, the strain energy could cause strong strata behaviors. A special geological structure model of the Tongxin mine is established based on the geodynamic division method. The distribution of regional structure stress field is determined by the rock mass stress analysis system. Based on this model, Tongxin mine is divided into five areas with high stress, eight areas with low stress and eight areas with gradient stress. The strong strata behaviors mostly occur in high stress areas. These results could provide guidance to predict the strength of regional or mine pressure and control strata behavior in different areas.