土壤和沉积物中NOM稳定性矿物学机制研究的理论与方法

土壤和沉积物中天然有机质(NOM)稳定性问题受到关注,主要是因为NOM的稳定性直接影响到大气中CO2的平衡与全球气候变化。此外,天然有机质还影响着土壤和沉积物中矿物的表面反应性、污染物的环境行为与生物有效性。因此,本综述在详细介绍土壤和沉积物中NOM稳定性矿物学机制研究的理论与方法的同时,也简略介绍了NOM的组成结构与反应性,并着重强调NOM/矿物微界面过程作用机制的重要性。许多研究表明,土壤和沉积物中NOM稳定性的矿物学机制主要包括矿物表面吸附和物理包裹。本综述目的是,介绍矿物保护的稳定NOM的分离、特性及其分析测定方法与技术,并且强调NOM稳定性矿物学保护机制系统性研究的重要性,以搞清矿物学保护机制在土壤和沉积物中NOM稳定保持中的贡献与重要性以及矿物学保护机制对天然有机质稳定性的调控作用,从而提高对土壤和沉积物环境生态的地球化学、矿物学的认识水平。     

成都平原农田区土壤重金属元素环境基准值初步研究

土壤重金属污染已成为制约人类社会发展及危害人类健康的重要因素,制定土壤重金属元素的环境基准值对控制土壤重金属污染及保护生态安全具有重要意义。以成都平原农田区为例,以保护地下水安全为目的,以室内模拟淋溶实验为手段,尝试性地计算了研究区不同类型土壤重金属元素的环境基准值。研究结果表明:(1)不同类型土壤各元素在土壤—水间的分配系数差异较大;(2)不同类型土壤Hg和Cd环境基准值差异不大,Hg环境基准值平均为0.3μg/g,Cd的变化范围为0.3～0.5μg/g;As和Pb环境基准值差异较大,As的变化范围为18～24μg/g;Pb的变化范围为24～41μg/g;(3)研究区土壤基本处于保护饮用水的安全范围之内,但黄壤中Pb、紫色土中Cd和Pb、棕壤中Hg和Pb具有潜在的影响地下水安全的生态风险。这对研究区进行风险评估具有重要的参考价值。     

防止张掖城市湿地周边地区土壤盐渍化的地下水临界深度确定

针对张掖北郊湿地区土壤盐渍化严重的实际情况,利用经验公式估算法和实测数据分析法研究和确定了张掖湿地区土壤盐渍化地下水临界深度值为2.9m,并讨论临界深度的确定对于防治土壤盐渍化和湿地周边地区生态保护的意义.     

基于主成分分析法的低山丘陵区土壤厚度快速评定方法与实践 ——以河南省罗山县为例

土壤厚度是农业生产、国土空间规划和生态保护修复等工作重要的基础信息.为探索低山丘陵区土壤厚度空间分布快速评定的有效方法,本研究对在河南省罗山县实测的593个土壤厚度数据进行了数理统计,总结了低山丘陵区土壤厚度密切相关的五种环境影响因子:坡度、土地利用类型、建造构造、海拔和植被覆盖率,并运用主成分分析法确定了上述影响因子对土壤厚度的影响权重为:0.151、0.303、0.263、0.184、0.100.最后进行了土壤厚度预测性制图,并通过野外实测土壤厚度数据进行了精度验证,结果显示该方法验证精度为72％,卡帕系数为0.672.该研究为低山丘陵区土壤厚度制图提供了一种快速高效精准的方法,为国土空间规划和生态保护修复提供技术支撑.     

岩溶山区土壤形成机制与石山改造利用

本文讨论分析了石灰岩山区土壤形成的机制,提出石灰岩山区土壤并非由石灰岩形成的观点,并对石灰岩山区提出分类保护、开发利用和改造的意见。      

干旱区土壤种子库的研究进展

土壤种子库在连接过去、现在和将来的植物种群和群落的结构和动态中起着重要的生态和进化作用,对保护和恢复干旱区植被起着重要的作用。从土壤种子库的研究方法、数量特征、分布格局、时空动态、与地上植被关系、年龄结构及影响因素等方面论述了干旱区土壤种子库研究的若干进展,展望了干旱区土壤种子库的研究趋势。     

浙江富硒土壤成因分类及开发利用现状

本文从浙江富硒土壤分布、有效性以及不同农产品硒含量特点,将富硒土壤划分为火山岩型、石煤型、燃煤型、湖沼型,研究了它们的成土母质、土壤类型和地球化学特征等方面的差别,阐述了它们的了利用现状,并对不同类型的富硒土壤的开发与保护提出科学建议。     

分形理论在描述土壤大孔隙结构中的应用研究

土壤大孔隙结构对土壤中水流及溶质运移以及地下水环境有着深刻影响。确定土壤大孔隙结构，可以很好地理解和预测水及溶质在有大孔隙土壤中的运移，保护地下水环境。由于土壤大孔隙的分布呈现分形规律，因此可以采用分形理论研究土壤大孔隙结构。根据CT对原状土柱各断面的扫描图像，得到了各断面土壤大孔隙的分形维数，为进一步研究土壤大孔隙的水力性质奠定了基础。     

浙江土壤重金属污染防治的对策建议

土壤重金属污染的防治及污染土壤的修复,是实施浙江“清洁土壤工程”的重要内容,也是一项紧迫而长期的工作。2012年10月31日。温家宝总理主持召开国务院常务会议,研究部署土壤环境保护和综合治理。会议提出,要保护土壤环境,防治和减少土壤污染、保障农产品质量安全,建设良好人居环境作为当前和今后一个时期的主要目标,进一步弄清土壤环境质量状况,建立土壤质量环境调查、监测制度,构造土壤环境监测网,完善相关政策、法规和标准,实施“土壤环境保护工程”,加快形成国家土壤环境保护体系,逐步完善环境质量。会议确定了五个方面的任务：     

成都经济区土壤质量地球化学评估

通过对成都经济区土壤重金属元素和有益元素含量高低的测定,参照相关国家或行业标准,根据土壤环境质量、土壤养分质量进行地球化学分等,最终进行土壤质量地球化学评价。结果表明:成都经济区土壤质量以Ⅲ、Ⅳ等为主,占调查面积的56.05%左右,土壤较清洁,养分较高,适宜农业生产;其次是Ⅴ、Ⅵ等,占总面积的39.02%左右,土壤存在不同程度的重金属污染现象,养分低,应加强管理;Ⅰ、Ⅱ等土壤面积仅占4.95%,是发展有机、无公害农业的理想区域,应注意强化保护和合理利用。     

祁连山七一冰川雪冰和冰川融水中正构烷烃和多环芳烃的分布特征及来源研究

2008年6月,在祁连山七一冰川采集雪坑、冰川融水和冰川末端冰样,经过大孔吸附树脂富集后,用GC-MS对样品中的正构烷烃(nC14～nC32)和多环芳烃进行了分析.结果表明,正构烷烃的含量在冰川融水中最高,雪坑次之,冰中最低;多环芳烃的含量在雪坑中最高,冰中最低,冰川融水界于二者之间.正构烷烃与多环芳烃都具有很强的疏水性,在固-液相分配过程中倾向于保留在残留固相中.由于冰川融水样品距冰川末端约1km,沿途地表土壤和植被会贡献部分正构烷烃,所以冰川融水中正构烷烃的含量最高.与正构烷烃不同,多环芳烃较易挥发,而且易被沿途土壤和植被所吸附,导致冰川融水中多环芳烃的含量降低.冰川末端冰中正构烷烃与多环芳烃的含量都很低,可能是由于冰川末端冰年代比较古老,受人类活动的污染较轻.正构烷烃的碳优势指数(CPI值)表明,七一冰川中的正构烷烃主要来自高等植物蜡和化石燃料燃烧产物的混合物,多环芳烃的荧蒽/芘(Fla/Pyr)和菲/蒽(Phe/Ant)比值表明,七一冰川冰雪和冰川融水中检测到的多环芳烃主要来自化石燃料的不完全燃烧.     

Clay smear: Review of mechanisms and applications

Clay smear is a collection of fault processes and resulting fault structures that form when normal faults deform layered sedimentary sections. These elusive structures have attracted deep interest from researchers interested in subsurface fluid flow, particularly in the oil and gas industry. In the four decades since the association between clay-smear structures and oil and gas accumulations was introduced, there has been extensive research into the fault processes that create clay smear and the resulting effects of that clay smear on fluid flow. We undertake a critical review of the literature associated with outcrop studies, laboratory and numerical modeling, and subsurface field studies of clay smear and propose a comprehensive summary that encompasses all of these elements. Important fault processes that contribute to clay smear are defined in the context of the ratio of rock strength and in situ effective stresses, the geometric evolution of fault systems, and the composition of the faulted section. We find that although there has been progress in all avenues pursued, progress has been uneven, and the processes that disrupt clay smears are mostly overlooked. We highlight those research areas that we think will yield the greatest benefit and suggest that taking these emerging results within a more process-based framework presented here will lead to a new generation of clay smear models.     

Recycled insular phosphates and coated grains: Case study from Little Cayman,British West Indies

Phosphatic limestones on the west end of Little Cayman, at an elevation of 3 to 4 m above sea level and ca 320 to 550 m inland of the coast, lie on top of a phytokarst surface that defines the upper boundary of the Pedro Castle Formation (Pliocene). These phosphatic limestones are formed of phosphatic lithoclasts, detrital phosphate grains, coated grains (glaebules), composite coated grains, biofragments and phosphate rafts that are held in a matrix that is formed of micrite, calcite cement, and non-crystalline masses formed of P, Al, Si and Fe. The phosphate in these limestones is primarily hydroxylapatite, whereas the overlying soils, found in some areas, are formed of hydroxylapatite, crandallite and minor amounts of boehemite, kaolinite and quartz. Textures in the lithoclasts and detrital phosphate grains indicate that they were derived from older insular phosphates that that were largely removed by mining in 1890 to 1895. The coated grains (glaebules) typically have nuclei formed of a detrital phosphate grains that are encased by non-crystalline cortical laminae that are composed primarily of Al with their variable red colour reflecting the variable Fe content. The phosphatic limestones developed in a low-lying coastal area where the guano produced by a large seabird colony that was close to or mixed with terra rossa and marine carbonates that were washed onshore during storms/hurricanes. The Al, Fe, Si and rare earth elements found in the phosphatic limestones came from the terra rossa. Critically, this study documents the complex depositional regimes and diagenetic processes that can exist at the interface of marine carbonates, coastal phosphates and terrestrial soils as sea-level fluctuations control phases of sediment accumulation that were periodically interrupted by periods of non-deposition.     

吉中呼兰镇地区呼兰群的划分及时代

吉中呼兰镇一带分布的轻变质岩系称呼兰群，曾划分为黄莺屯组、小三个顶子组和北岔屯组，对其划分和时代一直分岐较大。本文重新厘定了黄莺屯组，其主要为片麻岩、变粒岩、片岩等夹大理岩和石英岩，小三个顶子组由大理岩夹片岩和变粒岩组成；北岔屯组由大理岩、钙质砂岩和板岩组成，时代为晚志留世。北岔屯组在变质程度、岩性组合和时代上与另两组都有很大差别。因此，呼兰群仅包括黄莺屯组和小三个顶子组，时代为寒武－奥陶纪。     

Assessing the determinants of territorial cohesion: Evidence from Colombian departments

Territorial cohesion is a concept that is generating growing interest in both the academic-scientific and political arenas. This paper presents an approach to the analysis of territorial cohesion and, more specifically, proposes a definition of the concept and its dimensions in order to empirically test the approach on the Colombian departmental model. To this effect, a methodology was designed that, by using Data Envelopment Analysis (DEA) to calculate composite indices, measures and evaluates the level of territorial cohesion in Colombian departments from a multidimensional and integrative perspective, and identifies the factors that influence that cohesion. The results could provide useful data for policy makers in the design of public policies to influence factors that facilitate more balanced and inclusive territorial development. This is especially relevant in light of the recent signing and ratification of the Peace Agreement in November 2016, given that the Colombian Government is currently in the process of designing policies that have the potential to promote cohesion within its territories.     

豫北煤田焦作、鹤壁、安阳矿区二1煤层优势断裂构造地球化学特征

对豫北煤田焦作、鹤壁和安阳矿区二１煤层的对比样（构造煤和原生结构煤）进行了显微镜和扫描电镜下观察、镜质组反射率测试、Ｘ射线衍射分析和化学分析等。研究结果表明,构造煤因发生了断裂构造地球化学作用,其化学成分、元素成分和煤分子结构与原生结构煤明显不同：构造煤的挥发分含量（％）比原生结构煤一般要小０．５５～３．４８,平均要小１．５９;构造煤和原生结构煤相比,碳含量（％）平均增加了３．１,氢含量（％）平均     

烃类成因对天然气水合物成藏的控制

天然气水合物具有能量密度高、分布广、规模大、埋藏浅、成藏物化条件优越等特点,是未来的新型海洋能源。模拟实验显示,在烃类气体供给充分,温度低于平衡温度、压力大于平衡压力的条件下,天然气水合物的形成对于烃类气体的来源没有选择性。然而,已经获取的天然气水合物样品的分析显示,形成水合物的气体大多数为微生物成因气体,只有少量为热解气。最新的研究显示,形成生物气的营养源丰富,适合微生物的地质条件宽泛,生物气能够为形成天然气水合物提供充足的气源。通过对热解气和生物气形成天然气水合物条件的研究,以及对天然气水合物的地质分布特征的分析,笔者强调指出,与热解气相比,生物气更易于形成天然气水合物,而热解气形成的天然气水合物实际上意味着资源的严重破坏,并进一步认为,南海天然气水合物勘探方向,应集中在有利生物气形成富集以及有利于水合物形成的地质条件的分析和地质体的调查上,而不是在常规的深部油气藏附近展开。     

Migration and urban survival strategies in Windhoek, Namibia

Based on recent research in Windhoek, this paper demonstrates that it is the well established and widespread social linkages that persist between rural and urban households that are central to the ability of poor urban households to survive. Whereas informal coping mechanisms that include borrowing, piecework and credit are pervasive in rural areas of Namibia, intra-urban sources of food are poorly developed, and outside of kinship circles, social networks within Windhoek are used sparingly, even in times of greatest need. In addition, urban agriculture plays a very limited role at present in urban food supply. The research demonstrates that urban households that are most vulnerable to hunger are those that have limited social connections to the rural areas, and must rely on intra-urban opportunities to get food (including borrowing, begging, piecework and crime). The most vulnerable are female- and male-headed households with no access to farm income and limited/irregular urban incomes. In contrast, those with active rural-urban linkages enjoy significant transfers of food from rural areas that offset hunger and vulnerability in the urban context. Urban-rural reciprocity is therefore not only a one-way movement of people and resources from the urban to the rural areas, but also a transfer of food from rural to urban households.