基于ASTER与Sentinel-2A融合数据的云南普朗铜矿化蚀变信息提取

云南普朗铜矿区是我国提高战略性金属矿产铜矿资源的主要潜力地段,该矿区位于多云多雨山地高原区,采用传统地面调查方法开展找矿勘查工作受限较大,而遥感技术可在其中发挥重要作用。鉴于此,本研究选取ASTER和Sentinel-2A多光谱遥感数据,在光谱协同统一两种数据源的地表反射率基础上,采用高通滤波(High-Pass Filtering,HPF)的融合方法兼顾两种数据在短波红外波段和可见光近红外波段的优势,获取了具有高空间分辨率和高光谱保真度的ASTER-Sentinel-2A融合数据集;进而利用"比值+主成分分析法"与"主成分分析+能谱-面积法",开展了普朗铜矿区矿化遥感蚀变信息识别,并通过深入分析及野外验证,提出了对普朗铜矿蚀变信息分布特征及找矿潜力地带的新认识:(1)在原蚀变填图工作中判定为青磐岩化带的东部区域,重新进行了蚀变带的划分;(2)东部区域中新划分的钾化硅化带和绢英岩化带,具有较大找矿潜力。本研究可为普朗铜矿找矿勘查提供参考。     

滇西盈江地区新泡山离子吸附型稀土矿床成矿条件及找矿前景

滇西盈江地区是近年来离子吸附型稀土矿床找矿突破较大的地区,典型代表为腾冲岩浆弧内新发现的新泡山稀土矿床,为一中型离子吸附型稀土矿床,是滇西高海拔地区新发现的典型矿床。新泡山稀土矿床的发现对今后高海拔地区的找矿工作具有重要的示范意义。通过对新泡山稀土矿床的地质特征、风化壳结构特征、矿体垂向变化特征进行研究,认为新泡山稀土矿床类型为富钕轻稀土离子吸附型稀土矿床,并伴生有重稀土钇。滇西盈江地区与花岗岩有关的离子吸附型稀土矿主要受控于母岩稀土元素丰度、气候以及地形地貌。"沟-谷-盆"地貌两侧及周缘低缓山丘和平缓山坡、山脊是有利的成矿部位。结合区域找矿成果,认为研究区稀土矿找矿潜力较大,可达超大型远景规模,在后续的找矿工作中应加强对重稀土元素钇的评价。     

粤东北桃源铀矿床黄铁矿地球化学特征及其地质意义

粤东北桃源铀矿床位于华南铀成矿省武夷山铀成矿带,其矿床成因、成矿物理化学环境特征等还未开展深入研究。黄铁矿的地球化学特征往往能够有效地反映其形成时的地球化学环境。桃源铀矿床中黄铁矿与沥青铀矿成因关系密切。因此笔者在野外地质调查和岩相学基础上,利用LA- ICP- MS原位分析技术,对桃源矿床黄铁矿主、微量元素开展研究。结果表明：①黄铁矿主量元素w（Fe）=41.64% ~ 49.39%,平均值为45.83%;w（S）=50.56% ~ 57.62%,平均值为53.73%,w（Fe）/w（S）=0.73 ~ 0.98,平均值为0.85,表明其形成环境是一个微弱缺铁,相对富硫的相对封闭的地球化学环境;②黄铁矿中相对富集Si、Na、Al、K、Ca、Cr、Co、Ni、Ti、Cu、Ge、As、Se、Bi、Pb等微量元素;③绝大多数微量元素与主量元素Fe、S无明显线性关系,表明在黄铁矿形成过程中,这些微量元素的地球化学行为除受到类质同象因素的影响外,还受其他因素影响;④成矿元素U与部分微量元素显示出较好的正相关关系,其中Na、Ti等元素含量高表明与铀矿物在空间上紧密相关的黄铁矿形成于成矿早期的碱性热液蚀变阶段,而非成矿期,要早于铀成矿时间,并为铀成矿提供还原剂;⑤黄铁矿内部微裂隙发育,成矿期铀矿物容易进入其中,从而引起裂隙附近铀矿含量升高。伴随的高含量As表明其形成于中低温热液环境。     

Dynamic Response and Mechanical Behaviours of Geogrid for High Earth-rockfill Dams

Geotechnical and Geological Engineering - Due to the complexity of the interaction between the geogrid and the soil interface in high earth-rock dams, the method of replacing the grid with steel...     

Coupling a 1D-local inertia 2D hydraulic model for flood dispatching simulation in a floodplain under joint control of multiple gates

Natural Hazards - A 2D local inertial equations model coupled with a 1D hydraulic model was established to simulate flood dispatching in river and flood detention areas. A simplified first-order...     

Rapid forecasting of urban flood inundation using multiple machine learning models

Natural Hazards - Urban flood inundation is worsening as the number of short-duration rainstorms increases, and it is difficult to accurately predict urban flood inundation over a long lead time;...     

Identifying urban–rural differences in social vulnerability to natural hazards: a case study of China

Identifying and analyzing the urban–rural differences of social vulnerability to natural hazards is imperative to ensure that urbanization develops in a way that lessens the impacts of disasters and generate building resilient livelihoods in China. Using data from the 2000 and 2010 population censuses, this study conducted an assessment of the social vulnerability index (SVI) by applying the projection pursuit cluster model. The temporal and spatial changes of social vulnerability in urban and rural areas were then examined during China’s rapid urbanization period. An index of urban–rural differences in social vulnerability (SVI_D) was derived, and the global and local Moran’s I of the SVI_D were calculated to assess the spatial variation and association between the urban and rural SVI. In order to fully determine the impacts of urbanization in relation to social vulnerability, a spatial autoregressive model and Bivariate Moran’s I between urbanization and SVI were both calculated. The urban and rural SVI both displayed a steadily decreasing trend from 2000 to 2010, although the urban SVI was always larger than the rural SVI in the same year. In 17.5% of the prefectures, the rural SVI was larger than the urban SVI in 2000, but was smaller than the urban SVI in 2010. About 12.6% of the urban areas in the prefectures became less vulnerable than rural areas over the study period, while in more than 51.73% of the prefectures the urban–rural SVI gap decreased over the same period. The SVI_D values in all prefectures had a significantly positive spatial autocorrelation and spatial clusters were apparent. Over time, social vulnerability to natural hazards at the prefecture-level displayed a gathering–scattering pattern across China. Though a regional variation of social vulnerability developed during China’s rapid urbanization, the overall trend was for a steady reduction in social vulnerability in both urban and rural areas.

     

祁连山区多年冻土空间分布模拟

祁连山区位于青藏高原东北边缘,是亚洲水塔重要的组成部分,多年冻土的变化对生态系统和水资源平衡有着重要影响。基于青藏高原第二次综合科学考察、道路勘察钻孔点以及前人所获得的多年冻土下界资料,回归得出祁连山区多年冻土下界统计模型,借助ArcGIS平台在DEM数据的支持下,模拟出祁连山区多年冻土空间分布图。结果表明：祁连山区多年冻土分布的下界具有良好的地带性规律,表现为随经纬度增加而降低的规律;祁连山区多年冻土在空间分布上呈现出以哈拉湖为中心向四周扩散的分布格局;祁连山区总面积约为16.90×10⁴ km²,其中多年冻土面积约为8.03×10⁴ km²,占总面积约47.51%。多年冻土区与季节冻土区之间存在着有不连续多年冻土分布的过渡区,过渡区面积约1.43×10⁴ km²,占总面积约8.46%。     

陇中盆地及周边地区主夷平面演化与高原隆升

陇中盆地及周边地区是青藏高原向北东方向扩展的最前缘部位,其地貌演化过程的研究对于深入理解高原的隆升与扩展过程具有重要意义。鉴于夷平面在探讨高原隆升年代、幅度和过程方面的可靠性,首先总结陇中盆地及周边地区夷平面相关研究的前期成果,并结合最新年代数据,确定了不同区域主夷平面的发育和解体年代;再利用古河道拟合等方法定量评估了相关夷平面的隆升量;最后探讨了主夷平面的性质及其隆升过程。研究发现,陇中盆地及周边的地区的高海拔低起伏地貌面是被抬高的先存夷平面;不同区域主夷平面的发育与解体时间整体同步,它们自晚渐新世开始发育,并于晚中新世8~6 Ma左右解体;模拟结果表明,美武高原主夷平面自晚中新世以来相对陇中盆地隆升了约1 400~1 600 m,并且早更新世以来的隆升速率明显大于晚中新世-早更新世时期。     

川西北中二叠统栖霞组沉积特征及古地貌响应

川西北中二叠统栖霞组发育厚层白云岩储层,成为近年来四川盆地油气勘探开发的重点领域,但栖霞组有利相带分布和储层发育的主控因素并不明朗,制约了该地区油气勘探进展。根据野外露头、岩心、薄片、测井和地震资料,结合区域地质演化,对川西北栖霞组沉积特征、沉积格局以及古地貌进行研究发现:川西北栖霞组主要为碳酸盐岩台地沉积,自西北向东南方向依次发育盆地—斜坡相、台地边缘相和开阔台地相,并发育台缘滩或台内滩等若干亚相类型。其中栖一期沉积水体较深,为弱镶边碳酸盐岩台地形成期,台缘滩厚度薄,展布范围有限;栖二期为栖霞组主要成滩期,滩体厚度大,展布范围广,具典型镶边碳酸盐岩台地特征。栖霞组白云岩主要为台地边缘高能滩相沉积背景,栖霞组沉积期,研究区具西北高、东南低,西南高、东北低的古地貌格局,其不仅控制着台地边缘高能滩相的沉积分布,并进一步为该区白云岩储层发育奠定了基础,白云岩具有西北向东南、西南向东北逐渐减薄的特点。结合沉积演化和古地貌分析结果,认为古地貌为栖霞组白云岩发育的主要控制因素,西北及西南方向等古地貌高地为研究区栖霞组白云岩储层发育的有利沉积相带。