硫化物风化产酸对流域岩石风化和碳循环的影响——以黄河支流三川河流域为例

硫化物风化产酸可加速岩溶作用但抑制大气二氧化碳参与流域碳循环,其复杂的地球化学机制和过程待阐明。本文以黄河二级支流三川河流域为例,通过采集20个三川河及其支流地表水点样和30个柳林泉地下水点样,经实验测试获得了流域比较系统的水化学资料和δ¹³C、δ³⁴ S数据,运用碳、硫同位素分析与水化学平衡计量方法,量化了流域硫化物风化产酸对岩石风化作用的贡献以及对碳循环的影响。计算结果表明：煤系地层硫化物和矿床硫化物的氧化及大气酸沉降所形成的硫酸明显促进了流域碳酸盐岩的溶蚀,对碳酸盐岩溶蚀的贡献约占64.59%;柳林泉水石膏溶解来源的SO₄^2-占69%,河水中石膏溶解来源的SO₄^2-占30%,但这些部分SO₄^2-没有参与溶蚀作用,应当扣除;三川河流域平均岩石风化速率为10.02 mm/ka,其中碳酸盐岩、硅酸盐岩的风化速率分别为9.14 mm/ka和0.88 mm/ka,低于国内外很多流域;由于硫酸抵消了碳酸盐岩石风化作用对大气二氧化碳的吸收,流域岩石风化消耗大气/土壤CO₂通量为116.58 mmol/（km² ·a）,不足珠江流域的1/5,且硅酸盐岩风化的贡献占63.3%。

     

乌兰布和沙漠东北缘地表风沙流结构特征

在国家林业局磴口荒漠生态站长期监测的基础上,利用多种积沙仪,对乌兰布和沙漠东北缘流动沙丘、油蒿半固定沙丘、白刺半固定沙丘、油蒿固定沙丘、白刺固定沙丘5种典型下垫面近地面（0～100 cm）的风沙流输沙量进行了实地观测和对比分析。结果表明：（1） 输沙率（q）随高度（h）增加呈幂函数（q=ah^-b,R²≥0.8409）规律衰减,随风速（v）增大呈幂函数（q=av^b,R²≥0.9256）规律增加,42.8%～70.7%的输沙量分布在10 cm高度内,67.6%～90.0%的输沙量分布于30 cm高度内。当地表植被盖度达到40%以上时,输沙率下降至无植被覆盖地表输沙率的6.6%以下,可有效阻止地表风蚀。（2） 沙物质主要由粒径为50～250 μm的细沙和极细沙构成,各高度层风蚀物粒度组成服从单峰态分布,峰值在100～250 μm。随高度增加,风蚀物粒径范围趋于变窄,粒径趋于更细。（3） 起沙风多出现在WSW和NW方向,占全年起沙风的53.19%。风沙流中跃移输沙、蠕移输沙的空间分布在理论上应与风向频率分布基本一致,差异性主要由各方位风的强度和持续时间等因素导致。研究结果可为该区域防沙工程设计提供理论参考。     

鄂尔多斯盆地南部延长组富铀凝灰岩地球化学特征及形成机制

本文系统地研究了鄂尔多斯盆地南部延长组凝灰岩元素和同位素地球化学特征。结果表明：凝灰岩主量元素具有高K、高Al、Si中等至高、低Na的特征; REE总体特征为轻稀土富集、重稀土亏损,∑REE在4857～40212 μg/g 之间变化,Eu呈现出负异常,在034～082内变化,δCe范围在080～208之间; 微量元素中U含量在312～144 μg/g 之间,Ba、U、Th、Hf和Ce呈明显正异常,Nb、P、Ti和Rb呈现负异常。详细的分析表明：U的富集和一些微量元素如Ta、Dy、Lu等相关,Th与∑REE存在明显的正相关性,这些变化可能和盆地中铀矿的富集有关; 凝灰岩的硫同位素总体呈现深源特征。根据以上的研究对凝灰岩的形成原因及形成环境进行了探讨。鄂尔多斯盆地南部延长组凝灰岩来源于秦岭造山带火山作用,其中的铀元素富集是由于砂岩型铀矿中铀向凝灰岩迁移而被还原所致。本研究对盆地砂岩型铀矿的铀运移和富集机理认识具有一定指导意义。     

The Upper Middle Rhine Valley as a risk area

The Upper Middle Rhine Valley, granted the status of a World Heritage site, is well known for its unique inner narrow valley of Quaternary age with its historical legacy of numerous medieval castles and old towns. Less known is that this has always been a risk area of floods and gravitative mass movements. Up to the recent past, mainly ice floods caused enormous damage. The inhabitants of the valley were well aware that they lived in a risk area, but they had learned to handle the flood hazard. With the demise of ice floods over the last 40 years, due to climate change and because of the additional heating of the river water by power plants, the awareness of flood hazards has been much diminished, in contrast to that of potential damage by rockfalls and landslides which were also much feared in the past, though at the local level only. Still in the people’s memory is the Kaub catastrophe of March 10, 1876, when 28 persons were killed by a landslide. Nowadays, even minor rockfalls are a major threat, as they will affect the much-used traffic lines on both banks of the river, in particular the railroads. Therefore, since 2002, on behalf of German Rail (Deutsche Bahn, DB), all problematic slopes have been protected by costly steel-ring nets, although they are an aesthetic problem by UNESCO standards. The feeling of absolute safety created among the public is only subjective, though, as planners are well aware of. Moreover, the impact of modern climate change on slope stability is nearly unknown. Therefore, it is still necessary to develop a risk map for the narrow valley, with emphasis on gravitational hazards.     

西安城市化与水资源利用关系的量化研究

基于1997-2010年的统计数据,利用统计分析软件SPSS17.0的主成分分析导出西安城市化水平综合得分,进而运用所建立的回归模型分析了西安城市化与城市用水量、用水效益、人均用水水平之间的定量关系.结果表明:西安城市化发展中,生产用水量随城市化的推进呈三次函数曲线型降低,生活用水量则相反;用水效益与城市化呈线性增长关系;人均生产用水量随城市化水平的提高呈三次函数曲线型降低,人均生活用水量则相反.据此,提出未来西安在城市化推进过程中应重视优化产业结构,发展节水技术,改善用水结构,提高用水效益,实现城市化与水资源、水环境的协调发展.     

Resolving the landfill siting impasse: modelling technocratic and indigenous perspectives using GIS multicriteria approach

Increase in waste generation calls for an effective waste management as this has become a necessity for environmental sustainability. Several methods are adopted in managing waste, which include waste reduction, reuse, thermal treatment, recycling and landfilling. The landfill method is recognised as the most used of all the waste management methods in developing countries such as Ghana. However, the selection of a suitable landfill site is very difficult and tedious. This is because it involves a consideration of many factors such as environmental, topographic, economic, socio-cultural and civil engineering. This research sought to identify a suitable landfill site by applying GIS multicriteria and weighted overlay approach in the Bongo District of Northern Ghana. The analysis relied on criteria and weights provided by the technocrats and the indigenes in the district as a way of demonstrating how landfill siting impasse can be resolved by incorporating the various stakeholders. The results obtained provided clear areas for landfill sites in the study area from the technocratic and the indigenous perspectives. However, the technocratic perspective failed to include an important cultural criterion, sacred groves, as a factor. The indigenous perspective also compromised on the factor related to nearness to residential areas, and is equally not sufficient on its own. The optimal landfill sites, which meets the expectations of both the technocrats and indigenes, was identified. This perspective has produced technically favourable and socio-culturally acceptable landfill site. However, it is recommended an environmental impact assessment (EIA) be conducted to identify the full environmental and social cost of the site. It is concluded that in landfill site selection much attention be given to cultural factors in the same way as the technical factors.     

采煤塌陷地水域淹没范围模拟分析

采煤塌陷改变了矿区周边的地形地貌特征,使大量的耕地、园地变成水域。选择山东省龙口采煤塌陷区为研究对象,运用ArcGIS软件采集五期1:1万等高线和离散高程点数据,生成1×1 m2正方形网格的数字地面模型(DEM),以地表没有发生塌陷前的1978年DEM为标准高程数据,与其他各期DEM数据进行差值运算处理,得到不同时期采煤塌陷区面积。然后根据水利部门48年来的观测数据,计算出采煤塌陷区不同频率年份丰水期水文特征值,采用"无源淹没"分析法,计算给定水位条件下的采煤塌陷区水域淹没范围。     

质子化壳聚糖吸附除磷效能研究

本研究通过质子化方法强化壳聚糖的除磷效果,研究壳聚糖的质子化度、吸附时间、磷的存在形态等因素对质子化壳聚糖除磷效果的影响,结果表明,壳聚糖对水中总磷及磷酸根的吸附效果随着其质子化度的升高而呈现明显加强的趋势;质子化壳聚糖对水中总磷的吸附量随着时间的延长而增加,吸附时间在70-80min时达到最大吸附量;水溶液中磷的存在形态,影响质子化壳聚糖的除磷效果。     

天山高山冰缘环境的融冻泥流作用

根据实地观测结果分析，本文得出：天山冰缘环境发育的融冻泥流分布在海拔２５００─３６００ｍ间的阴坡。融冻泥流发育要求地下含水丰富，粒度以细粉砂为主，地表坡度１０─３１°。融冻泥流的形态多数为长宽比小于１的叶状，少量为舌状。融冻泥流表面平均运动速度为１１．１４ｃｍ／ａ，舌前缘前进的平均速度的１．８６ｃｍ／ａ，中轴部位的运动速度比两侧大。     

中国地震预报论坛2023年度学术交流大会在四川康定召开

中国地震学会地震预报专业委员会和四川省地震局于2023年8月15—19日在四川省康定市联合举办了中国地震预报论坛2023年度学术交流大会,来自全国地震行业内、外8所大学、4个中科院直属科研院所与23个地震行业直属科研院所及省市级分支机构共35个单位的100余名代表参加了此次会议。学术交流设置了12个专题;会前征集到论文96篇,会期交流报告78个,其中口头报告23个,张贴展板55个;23个口头报告中,大会特邀报告6个;从55个张贴报告中,评选出优秀报告6个,最佳设计创意报告1个。为了配合活断层野外识别的科普培训,本次大会将原计划以 “制约地震三要素的因素与地震三要素预报的瓶颈问题” 为主题的大会圆桌讨论改成了 “鲜水河断裂带高震级危险性分析” 的专题培训讲座,讲座之后再适时举行了 “如何强化高危险区的临震监测与临震跟踪预报能力” 的专题讨论。对2022年泸定6.8级地震的交流讨论提出了新的科学问题。大会不仅重视学术交流,还兼顾了科学传播的普及,利用当地的科普资源,因地制宜地组织了为期一天的鲜水河断裂带活动特征的野外识别科普培训。地震预报论坛学术交流大会全体与会代表参加了此次野外实训活动,活动中邀请了著名的鲜水河断裂带活动特征研究专家现场授课,增强了地震预报与地震地质领域的跨学科交流,强化了学术交流的效果。