鄂尔多斯盆地东南缘上三叠统长8段砂岩储层成岩作用与孔隙演化

鄂尔多斯盆地东南缘上三叠统延长组长8是该区油藏的主力储集层,主要为一套湖泊-三角洲相砂岩,储集岩主要为长石砂岩及长石岩屑砂岩。以岩心观察为基础,结合薄片鉴定、扫描电镜、压汞测试、X-衍射、包裹体测温、Ro测定等方法认为,研究区延长组砂岩经历了压实、胶结、溶解、交代等成岩作用,成岩阶段已达中成岩阶段A期。成岩作用成为控制该区物性的一个关键因素,早期的机械压实和胶结作用使原生孔隙大量丧失,有机质分解形成的酸性流体使储集层中长石等易溶组分的溶蚀对储层物性起到重要的改善作用,成岩阶段后期以（含铁）碳酸盐胶结物为主的胶结又使砂岩致密化。成岩作用中的孔隙演化特征对鄂尔多斯盆地上三叠统延长组低渗透储集层的开发具有积极的意义。     

1995-2015年中国省际人口迁移网络的演化特征——基于异质性劳动力视角

自户籍制度放宽以来,中国经历了大规模的人口迁移.其中,异质性劳动力(高技能劳动力、普通劳动力)在迁移过程中表征出不同的空间格局和网络组织特征,对地区经济发展产生各异的影响.本研究基于人口普查和抽样调查微观抽样数据,使用复杂网络理论对1995-2015年中国异质性劳动力迁移的时空格局和网络演化展开分析,并分析了格局背后的...     

The dependence of galaxy formation on cosmological parameters: can we distinguish between the WMAP1 and WMAP3 parameter sets?

We combine N -body simulations of structure growth with physical modelling of galaxy evolution to investigate whether the shift in cosmological parameters between the first- and third-year results from the Wilkinson Microwave Anisotropy Probe ( WMAP ) affects predictions for the galaxy population. Structure formation is significantly delayed in the WMAP3 cosmology, because the initial matter fluctuation amplitude is lower on the relevant scales. The decrease in dark matter clustering strength is, however, almost entirely offset by an increase in halo bias, so predictions for galaxy clustering are barely altered. In both cosmologies, several combinations of physical parameters can reproduce observed, low-redshift galaxy properties; the star formation, supernova feedback and active galactic nucleus feedback efficiencies can be played off against each other to give similar results. Models which fit observed luminosity functions predict projected two-point correlation functions which scatter by about 10–20 per cent on large scale and by larger factors on small scale, depending both on cosmology and on details of galaxy formation. Measurements of the pairwise velocity distribution prefer the WMAP1 cosmology, but careful treatment of the systematics is needed. Given present modelling uncertainties, it is not easy to distinguish between the WMAP1 and WMAP3 cosmologies on the basis of low-redshift galaxy properties. Model predictions diverge more dramatically at high redshift. Better observational data at   z > 2  will better constrain galaxy formation and perhaps also cosmological parameters.     

The minimum orbital period in thermal time-scale mass transfer

We show that the usual picture of supersoft X-ray binary evolution as driven by conservative thermal time-scale mass transfer cannot explain the short orbital periods of RX J0537.7–7034 (3.5 h) and 1E 0035.4–7230 (4.1 h). Non-conservative evolution may produce such periods, but requires very significant mass loss, and is highly constrained.     

青海拉鸡山构造带是裂谷还是构造窗——与王二七研究员商榷

拉鸡山构造带东西长逾650km,展布于由元古宇组成的结晶地块内部，是一条早古生代火山岩极为发育的构造带。长期以来众多学者对拉鸡山进行大地构造学、岩石学研究。作者曾在拉鸡山从事多年野外调查工作，研究认为该地区无论在区域地质学、岩石学、构造变形学还是在大地构造演化方面其早古生代构造演化史皆具典型的裂谷带特征。晚古生代以来，经历了陆内多阶段造山过程，而为后期多阶段抬升的构造窗观点值得商榷。     

中国荒漠化分区与时空演变

荒漠化被列入威胁人类生存的十大环境与发展问题之一,中国作为世界上荒漠化严重的国家,荒漠化形势十分严峻。本文通过遥感手段,以中国陆域国土范围（除台湾、香港和澳门）的31个省、市、自治区为研究区域,对1975年、2000年与2017年研究区数据进行沙化、盐渍化、水蚀荒漠化专题因子时空演变的综合研究,根据地域分异、发生学及多级序列等原则将将中国划分为8个荒漠-荒漠化区,42个荒漠-荒漠化亚区和36个荒漠-荒漠化小区。以不同时期荒漠化土地类型图为依据,采用荒漠化面积变化量与荒漠化重心迁移轨迹指标进行荒漠化演化分析。为具体说明不同区域荒漠化程度,本研究根据一定时期内荒漠化土地面积增加或减少的百分比将荒漠化演化分为7种类型,通过分析得到不同荒漠化区域的时空演化及不重心迁移,据此提出中国荒漠化的重点治理目标区及防治建议。研究结果表明：① 中国荒漠、荒漠化土地种类较多,重度荒漠化面积25.18×10⁴ km²,占荒漠化总面积的19.59%;② 1975-2017年,中国荒漠化发生明显逆转,与1975-2000年相比,2000-2017年全国的荒漠化强度显著下降,原因是荒漠化加重区面积减少以及荒漠化减弱区面积增加;③ 1975-2000年与2000-2017年,各区内荒漠化重心点坐标迁移具有同向性。本研究在分析荒漠化土地分布、形成和演变机制的基础上,进行了荒漠化分区。通过对不同荒漠化地区的面积百分比变化的比较,得到了不同时期荒漠化的时空演化模式,并分析了荒漠化演化的特点和差异。     

基于多变量统计分析和水化学特征的海水入侵特征研究——以青岛市崂山区为例

沿海地区地下水环境问题日益突出,进行地下水水化学特征及演化规律的研究,能够更有效地开展地下水环境的监测和保护。以青岛市崂山区地下水为研究对象,综合运用统计分析、主成分分析、Piper图解法、HFE-D图解法、Chadha’s矩形图法等方法,对研究区海水入侵特征与地下水化学特征演化进行分析,探究地下水水化学特征及演化规律,并进一步评价了海水入侵现状。结果表明,研究区地下水以Na+、Ca2+、Cl−、${\rm{SO}}_4^{2-}$为主要优势离子,地下水化学类型多为Cl·SO4-Na型和SO4·Cl-Ca·Mg型。地下水中Cl−浓度变化幅度较大,且其均值超出了有无海水入侵的分界值（250 mg·L−1）,地下水可能发生一定程度的海水入侵;青岛市崂山区地下水呈中性至弱碱性（pH均值=7.0~8.0）,是沿海地区长期的水文地球化学过程的影响;地下水化学变化主要受自然因素（岩石与水的相互作用）或人为因素（农业和家庭活动）的控制;采用反距离加权（IDW）方法,结合地理信息系统（GIS）,进行海水入侵位置的空间映射,研究结果表明崂山区海水入侵主要分布于江家土寨东−浦里社区北入侵段,王哥庄−港西−港东入侵段、仰口湾入侵段、登瀛村−栲栳岛入侵段。     

Mantle plumes and the metamorphism of the lower crust and their influence on basin evolution

Since the stretching model appears to be not applicable to the subsidence of accretionary crust, basins located on this crust type may have an alternative origin. Examples of such basins are the West Siberia Basin and the North German Basin. Both basins showed intensive volcanism and magmatism during the initial phase of their development. Remarkably, the West Siberia Basin is closely located to the (hotspot related) Siberian flood basalts with a similar Permo-Triassic age, and the location of the North German Basin in Permian times is identical with the present day position of the Tibesti hotspot in Northern Africa. These two basins may have specific relations to hotspot heat sources of the Earth's underlying mantle. Due to these heat sources, thermal metamorphism within the lower layers of the (accretionary) crust may occur, resulting in rock density increase and subsequent shrinkage of the affected rock volumes. These shrinkage processes will lead to the development of topographic lows, their filling with sediments, and the subsequent start of an exponentially declining isostatic/metamorphic basin subsidence. In addition to the analyses of metamorphic processes, potential field anomalies, temperature fields, and histories of subsidence have been integrated into one single model that can explain the development of the North German Basin. Similarly, the East African Rift and Eifel Hotspots affected parts of the overriding continental plates. The East African Rift Hotspot can be traced back to the Afar flood basalts and the Dniepr–Donets Basin, whereas the Eifel Hotspot can be linked to the North Sea Basin. Continental drift templates, present day hotspot locations, flood basalt areas, metamorphic facies as function of temperature, and crust categories are taken as published in recent literature.     

渤海、北黄海海冰与气候变化的关系

渤海和北黄海的冰情随着历年冬季气候差异而不同.暖冬海冰覆盖范围不足海域的15%,而寒冬可覆盖海域80%以上.概述了海冰监测及资料来源.冰覆盖面积、外缘线位置和冰况等级等被作为反映结冰海域冰情的指标.用大连和营口站的气温表示渤海、北黄海海域的局地气候.用1952～2000年大连的月平均气温描述冰情的变化.给出冰情指数由1952/1953年到1999/2000年随大连站月平均气温变化.影响渤海和北黄海冰情和气候的因子很多,诸如大气环流的演变和太阳活动等.分析了多种因子与冰情的滞后相关,指出20世纪90年代渤海冰情持续偏轻与全球气候变暖趋势相当一致;渤海和北黄海冰情的年际变化与El-Nino现象以及太阳活动周期有关;讨论了海冰季节演变的特征