高分辨率遥感影像在岩墙地质体信息提取中的应用

高分辨率遥感影像可明显表现地物的几何结构和纹理特征,从而使得在较小空间尺度上观察地物细节变化、进行大比例尺遥感制图成为可能。利用高分辨率QuickBird遥感影像,对新疆巴楚县麻扎尔塔格山地区的岩墙进行计算机辅助地质解译,共获得1227条岩墙。结合GIS空间分析方法获得了解译岩墙长度、走向分布等特征。结果表明:该地区76%的解译岩墙走向为NNW(135°~180°);QuickBird能够满足1∶2.5万地质调查的要求;通过地质分析综合解译结果获得了麻扎尔塔格岩体内部存在发育岩墙、岩墙形成应晚于内部的正长岩体的新认识。探讨并验证了高分辨率遥感影像在中小规模地质体解译中的可行性和有效性。     

近三十年保安湖大型底栖动物群落结构演变及其构建机制

保安湖是江汉湖群的一个典型浅水湖泊。近几十年来,随着经济的快速发展,保安湖面临多重人类压力影响,富营养化问题日趋严重。历史上曾开展过数次的保安湖底栖动物调查,但有关群落结构的长期变化及其驱动机制改变的认知仍为空白。本研究基于30余年（1986 2019）的多次调查数据,探索保安湖底栖动物的群落演变规律及其群落构建机制。研究共记录保安湖底栖动物5门10纲25目49科110属170种（历史记录154种,现场调查51种）。总物种数由1992年的107种降为2019年的51种;平均密度由1992年的433 ind．/m2增加到2019年的2177.6 ind．/m2;平均生物量由2001年的160.6 g/m2降低为2019年的26.7 g/m2。优势种在1987年有寡毛类、水生昆虫和软体动物多个类群,其后逐步演变为现阶段少数几种耐污的寡毛类和摇蚊类,如霍甫水丝蚓（Limnodrilus hoffmeisteri）、中国长足摇蚊（Tanypus chinensis）、红裸须摇蚊（Propsilocerus akamusi）等,而多年生大型软体动物衰退明显。PERMANOVA和SIMPER分析结...     

Stratification and mixing of a post-glacial Neoproterozoic ocean: Evidence from carbon and sulfur isotopes in a cap dolostone from northwest China

To improve our knowledge about the geochemical and environmental aftermath of Neoproterozoic global glaciations, we analyzed stable isotopes (δ¹³C, δ¹⁸O, δ³⁴S) and elemental concentrations (Ca, Mg, S, Sr, Fe, and Mn) of the ～ 10-m-thick Zhamoketi cap dolostone atop the Tereeken diamictite in the Quruqtagh area, eastern Chinese Tianshan. Available chemostratigraphic data suggest that the Tereeken diamictite is probably equivalent to the Marinoan glaciation. Our new data indicate that organic and carbonate carbon isotopes of the Zhamoketi cap dolostone show little stratigraphic variations, averaging ? 28.2‰ and ? 4.6‰, respectively. In contrast, sulfur isotopes show significant stratigraphic variations. Carbonate associated sulfate (CAS) abundance decreases rapidly in the basal cap dolostone and δ³⁴S_CAS composition varies between + 9‰ and + 15‰ in the lower 2.5 m. In the overlying interval, CAS abundance remains low while δ³⁴S_CAS rises ～ 5‰ and varies more widely between + 10‰ and + 21‰. The range of δ³⁴S_py of the cap dolostone overlaps with that of δ³⁴S_CAS, but direct comparison shows that δ³⁴S_py is typically greater than δ³⁴S_CAS measured from the same samples. Hypotheses to explain the observations must account for both the remarkable sulfur isotope enrichment of pyrites and the inverse fractionation. We propose that CAS and pyrite were derived from two isotopically distinct reservoirs in a chemically stratified basin or a basin with a sulfate minimum zone. In this model, CAS was derived from shallow, oxic surface waters with moderate sulfate concentration and depleted in ³⁴S due to the post-glacial influx of sulfur from continental weathering. In contrast, pyrite was derived from anoxic bottom waters (or a sulfate minimum zone) with low sulfate concentration and ³⁴S enrichment due to long-term syn-glacial sulfate reduction. The rapid shift in CAS abundance and sulfur isotope composition within the cap dolostone is interpreted to reflect the mixing of the two reservoirs after initial deglaciation. Comparison with other post-Marinoan cap carbonates shows significant spatial heterogeneity in δ³⁴S_CAS, which together with strong temporal variation in δ³⁴S_CAS, points to generally low sulfate concentrations in post-Marinoan oceans.     

13世纪以来中国海洋盐业动态演变及驱动因素

海洋盐业是中国海洋经济的重要部分,也是沿海传统产业之一,13世纪以来不断发展演变。将沿海分为北、东、南3个地带,搜集整理与海盐经济相关的多种历史文献及方志资料,运用地理学方法分析评估了海洋盐业百年尺度的动态演化过程,并比较了资源环境与管理政策的驱动作用及其差异。研究表明：① 沿海盐业表现为传统煎法长期主导、逐步废煎改晒的过程,不同盐区的演化进程存在显著差异,北部盐区最快,东部次之,南部整体发展缓慢;② 海盐生产重心长期位于东部的两淮盐区,19世纪后期向北部盐区快速迁移;③ 资源环境与生态差异促进了各岸段海盐生产演化分异,垄断性管理政策迟滞了海洋盐业的空间集聚进程,未来沿海开发与海洋盐业的可持续发展将主要依靠基于资源生态约束的管理政策与技术。     

Rare-earth element mobility during ore-forming hydrothermal alteration: A case study of Dongping gold deposit Hebei Province,China

REE mobility during hydrothermal ore-forming processes has been extensively investigated in recent years and the potential of REE to provide information about ore forming processes has commonly been recognized.The Dongping gold deposit,which is located in northwestern Hebei Province,China,occurring in the inner contact zone of the Shuiquangou syenite complex,is spatially,and probably genetically,related to the syenite,the deposit was formed under the moderate to high temperature(220℃ to 320℃),weakly acidic to weakly alkaline,rather high fo2(lgfo2=-30～-34)environment.The REE study of the host rocks,altered wall rocks,ores and gangue minerals from the deposit suggests that the REEs have been mobilized and differentiated during K-feldspathization and silicification.The extremely altered syenite enveloping auriferous quartz vein shows positive Ce anomaly and larger LREE/HREE ratio than that of the unaltered syenite.The REE concentrations and patterns of the ores are determined by the ore types and mineral assemblages,LREE/HREE ratios in the gangue quartz and hydrothermal Kfeldspars are relatively low.The most significant observation is that the gangue quartz shows significant positive Eu anomaly,whereas the hydrothermal K-feldspars show less significant or no positive Eu anomaly at all relative to the primary feldspar in the unaltered syenite. It is evident that the REEs are mobile during K-feldspathization and silicification in the ore forming process.Weak to moderate K-feldspathization caused REE mobility without apparent differentiation with the exception of extreme K-feldspathization and silicification which resulted in significant depletion of HREE and Eu and relative enrichment of Ce.The REE,Y,U,Th and Au contents of the syenite decrease as the degrees of K-feldspathization and silicification of the rocks increase towards the auriferous quartz veins.As the ores were deposited under a rather oxidized environment,Ce^4 predominated over Ce^3 .The precipitation of the former in the form of CeO2 or absorpted onto the secondary mineral assemblage resulted in the inconsistent removal of the REE and the relative Ce enrichment in the strongly altered rocks.in contrast,Eu was present mainly in a low valence state (Eu^2 ).The geochemical differences from the other REE^3 and much less sites in the secondary minerals to accommodate the Eu released form the original minerals resulted in the enrichment of Eu in the fluids.The mobility and differentiation of REE and the coherent mobilities of Y,U,Th and Au also support the argument that the syenite is one of the source rocks for gold mineralization.The REE contents and patterns of the altered rocks enveloping the auriferous quartz vein could be used as a guide for locating ore veins in mineral exploration.     

颅脑外伤分类的CT特征

本文目的在于进一步提高对多种颅脑损伤的认识水平。所用材料和方法为本组１３５例,男９８例,女３７例,年龄４＿７７岁,平均年龄２４．８３岁。车祸伤９３例,跌伤２８例,击伤１４伤,１０１例有昏迷史,全部病例均作头颅ＣＴ轴位平扫。从相互伴发的多种颅脑损伤的角度,详细分析了它们的ＣＴ表现。结果得到了１３５例中,有多种类型颅脑损伤１３３例,单纯脑挫裂伤２例;硬膜外血肿１０４例,合并同一部位骨折７５例,占７２．１５％,合并脑挫裂伤占７０．３７％;硬膜下血肿２０例,位于外力对冲部位１５例．占７５％,合并脑挫伤裂伤１２例,其中１１例邻近硬膜下血肿;外伤后２小时内ＣＴ检查,并于外伤后４小时至５天内ＣＴ复查４７例,发现病变进展３８例,占８０．９５％。结论为硬膜外血肿多伴同部位骨折;在硬膜外血肿中,伴发的脑挫裂伤多位于对冲部位;硬膜下血肿多发生于对冲部位;颅脑损伤后,短期内病变可能会继续发展。     

新疆西准噶尔地区两类蛇绿岩中橄榄岩的矿物学研究

两类蛇绿岩中变质橄榄岩的矿物表现出的共同特征是:从二辉橄榄岩→斜辉橄榄岩→斜辉辉橄岩→纯橄岩→铬铁矿石,其橄榄石、斜方辉石和单斜辉石的Mg/(Mg+Fe)(矿物牌号)依次升高,表现出富Mg贫Fe的演化趋势;铬尖晶石的Cr/(Cr+Al)亦同时升高,表现为富Cr贫Al的演化特征。 变质橄榄岩中的矿物均是原始上地幔岩部分熔融的残余物。在部分熔融过程中,橄榄石与铬尖晶石是生成相矿物,而斜方与单斜辉石则是消失相矿物,正是通过两种辉石的不断消失,岩石才从二辉橄榄岩依次转化为纯橄岩,并造成纯橄岩与铬铁矿的紧密伴生。在此过程中,矿物成分时刻都在变化,造岩矿物向富Mg贫Fe,金属矿物向富Cr贫Al方向调整,这与实际测定结果是一致的。     

Wind tunnel simulation experiment and investigation on the electrification of sandstorms

~~Wind tunnel simulation experiment and investigation on the electrification of sandstorms~~     

土壤—作物系统中硒的地球化学特征及影响因素研究(代序2)

硒是人体和动物必需的微量元素,而植物硒是人体摄入硒的重要来源。探究土壤-作物系统中硒的地球化学特征及其影响因素,从土壤地球化学的角度评价硒的生物有效性、进而建立富硒农作物模型具有重要意义。本文描述了世界和中国土壤中硒含量的分布情况,并从成土母质和土壤理化性质方面分析土壤中硒含量的影响因素。由于土壤中的硒形态是评价土壤硒生物有效性的关键,本文对土壤生物有效性硒的提取方法进行评述,且从土壤硒的赋存形态、土壤生物有效性硒的主控因素出发,探究土壤理化性质对农作物吸收硒的影响。此外,本文归纳总结了基于土壤理化性质的农作物硒含量回归模型,旨在分析农作物硒含量的主要影响因素,并以此预测农作物中的硒含量。     

论中国东部大型盆地区及邻区地质-地球物理复合尺度解析

作为对中国东部陆缘地带大型盆地区及邻区地质－地球物理综合研究的部分结果,本文的基本认识：（1）穿过松辽盆地的1孙吴－双辽断裂可能是东倾伯低角度壳内断裂;（2）松辽盆地和渤海湾盆地可能属于“混合型裂谷盆地”;（3）东海盆地台北坳陷处在多期次张性应力场环境中,使在其西部附近产生张性正断层系;（4）欧亚大陆东部新生代区域构造运动总体处于右旋走滑拉张环境,其动力因素包括板块运动和地幔物质运动;（5）研究区莫霍面具有较为复杂的变化;（6）复合尺度研究方法是地质－地球物理综合分析的必要手段。