Lake Floor Morphology and Sediment Architecture of Lake Torneträsk,Northern Sweden

Here we present datasets from a hydroacoustic survey in July 2011 at Lake Torneträsk, northern Sweden. Our hydroacoustic data exhibit lake floor morphologies formed by glacial erosion and accumulation processes, insights into lacustrine sediment accumulation since the beginning of deglaciation, and information on seismic activity along the Pärvie Fault. Features of glacial scouring with a high‐energy relief, steep slopes, and relative reliefs of more than 50 m are observed in the large W‐basin. The remainder of the lacustrine subsurface appears to host a broad variety of well preserved formations from glacial accumulation related to the last retreat of the Fennoscandian ice sheet. Deposition of glaciolacustrine and lacustrine sediments is focused in areas situated in proximity to major inlets. Sediment accumulation in distal areas of the lake seldom exceeds 2 m or is not observable. We assume that lack of sediment deposition in the lake is a result of different factors, including low rates of erosion in the catchment, a previously high lake level leading to deposition of sediments in higher elevated paleodeltas, tributaries carrying low suspension loads as a result of sedimentation in upstream lakes, and an overall low productivity in the lake. A clear off‐shore trace of the Pärvie Fault could not be detected from our hydroacoustic data. However, an absence of sediment disturbance in close proximity to the presumed fault trace implies minimal seismic activity since deposition of the glaciolacustrine and lacustrine sediments.     

我国东部沿海三大经济区区域经济的空间自相关分析

本文以我国东部沿海三大经济区域——环渤海、长三角、珠三角为研究对象,依据空间统计学的空间自相关方法,采用以高速公路里程数为影响因子改进的空间权重矩阵,以及全局和局部Moran I指数模型,通过ArcToolbox空间分析工具分析三大区域经济空间格局。研究结果表明,长三角与珠三角区域发展呈显著的空间正相关,长三角地区较之其他两地区发展最为成熟,发展极辐射大。同时地理环境对于区域经济发展作用明显,发展核心城市集中于沿江地区或平原地区。     

西藏高原湖泊的基本特征及放射性元素调查

西藏高原湖泊星罗棋布,形态各异,是世界上湖泊最多最集中的地区之一。通过对西藏高原湖泊的形成和几个典型湖泊的基本特征、水化学条件以及放射性元素特征进行了阐述,发现部分湖泊铀浓度较高,认为在湖泊中寻找铀资源是未来铀资源勘查值得参考的方向之一。     

黄旗海湖泊沉积记录的早中全新世大湖期环境的差异性

内蒙古黄旗海H6剖面揭示了最近间冰期古湖泊涨缩的一个完整旋回。基于OSL年代、粒度并结合沉积物地球化学等数据,分析了黄旗海在早、中全新世（约（11.4±1.1～6.7±0.7）ka）大湖期指标记录特点与环境意义。研究认为黄旗海全新世大湖期可分为三个阶段:1）（11.4±1.1～9.3±0.9） ka BP,半深水环境、湖水盐度低、流域存在有利于化学风化的湿润气候条件;2）（9.3±0.9～7.7±0.7） ka BP,湖水变浅、湖泊萎缩、湖泊盐度升高,流域可能存在不利于化学风化的干燥气候;3）（7.7±0.7～6.7±0.7） ka BP,大湖期结束,指标记录存在剧烈波动,揭示气候具有宽幅震荡特征。同时,研究初步认为Mn/Li比值可以作为流域化学风化的指标指示。     

Mesozoic collision-related magmatism and crust–mantle interaction along the Anhui segment of the Yangtze River Valley,east-central China

The middle segment of the Yangtze River Deep Fault Belt, located in the foreland of the Dabie orogen, contains widely exposed volcanic–intrusive complexes that formed during two episodes of magmatism (post-collisional and post-orogenic), reflecting crust–mantle interactions during the Late Jurassic (J₃) to Early Cretaceous (K₁). This article summarizes research on the Mesozoic igneous suites and xenolith suites in the area along the Yangtze River. ‘Post-collisional magmatism’ occurred during lithospheric extension at ～145–130 Ma. Its beginning and end are marked by gabbroic xenoliths and pyroxene cumulates within intrusions at Tongling, and by alkali-rich magmatic rocks. The association includes peraluminous silicic rocks and metaluminous mafic–felsic igneous suites, ranging from medium-K to high-K calc-alkaline to shoshonitic compositions. Taking the Tongling region as an example, quartz monzodiorite yields a sensitive high resolution ion microprobe (SHRIMP) zircon U–Pb age of 139.5 ± 2.9 Ma, and granodiorite yields an age of 135.5 ± 4.4 Ma. These intrusive rocks contain 52.79–66.46 wt.% SiO₂, 13.12–17.73 wt.% Al₂O₃, 1.37–4.62 wt.% MgO, 3.86–6.84 wt.% FeO^T, and 4.71–7.87 wt.% total alkalis (Na₂O?+?K₂O). ACNK values range from 0.62 to 1.20, and ANK values from 1.45 to 3.48. ‘Post-orogenic magmatism’ occurred during lithospheric delamination at ～130–120 Ma. The start of magmatism was marked by the formation of gabbro containing spinel lherzolite xenoliths in the Nanjing–Wuhu Basin (NWB), and its end was marked by the generation of feldspathoid phenocryst-bearing phonolite in the NWB and the Lujiang–Zongyang Basin (LZB), respectively. The association that formed during this episode ranges from alkaline to peralkaline. Taking the Niangniangshan Formation in the NWB as an example, the Nosite phonolite yields a whole-rock monomineral Rb–Sr isochron age of 120 ± 9 Ma, and contains 49.92–60.09 wt.% SiO₂, 17.67–20.65 wt.% Al₂O₃, 0.08–2.45 wt.% MgO, 1.32–6.62 wt.% FeO^T, and 9.24–13.92 wt.% total alkalis (Na₂O?+?K₂O). ACNK values range from 0.72 to 1.24, and ANK values from 1.03 to 1.35.

The two magmatisms correspond to two episodes of crust–mantle interaction. The first involved intensive interaction between middle–lower crust and underplated basaltic magma derived from the upper mantle lithosphere, whereas the second involved minor interaction between the middle–lower crust and basaltic magma derived from the lower lithospheric mantle.     

加蓬海岸盆地南、北次盆成藏特征对比

加蓬海岸盆地属于被动大陆边缘盆地。盆地沉积盖层主要由白垩系、古近系和新近系组成,沉积地层组合具有明显的三分性,包括早白垩世盐下层系、早白垩世晚期阿普特期盐膏层和晚白垩世至新近纪盐上层系。根据目前的油气发现,北加蓬主要富集盐上油气资源,南加蓬主要富集盐下油气资源。从构造沉积背景、油气地质条件、油气发现规模、油气平面分布、油气勘探潜力5方面对南、北次盆进行对比,分析南、北次盆的油气聚集差异,结合勘探现状分析其勘探潜力,并指出南加蓬次盆勘探难点为圈闭识别,北加蓬次盆的勘探难点是砂体预测。     

青海五道梁地区渐新统雅西错组地球化学特征及成矿作用浅析

以五道梁地区1∶20万水系沉积物测量更新数据为基础,以渐新统雅西错组为研究对象,利用地层汇水域水系沉积物测量元素原始数据进行了参数统计,通过相对丰度、R型聚类分析和因子分析,分析了地层中各元素的含量分布特征及元素间的亲疏关系,进一步浅析了地层在成矿中的作用.认为雅西错组高钙碳酸盐岩建造环境显著,Ba、Sr、Ag、As、Cd、Mo在地层中有不同程度的富集.地层有一定的含矿性,其中Ag趋向于与黏土岩伴随的硅质砂岩类中,其他在碳酸盐岩中.在后期岩浆热源作用下,主要成矿元素能进一步富集成异常或成矿.     

基于遥感技术的海岸带土地利用、覆被信息提取方法研究

本文以地处莱州湾东海岸的莱州市为研究区域,以TM影像为主要信息源,在分析各类地物分类效果的基础上,结合区域特点和地物光谱特征,综合利用两期典型季相的遥感图像,并针对每一种土地利用类型确定最佳信息提取影像,提出了基于光谱、地形等多种知识的分层信息提取方法.结果表明该方法分层目标明确,分类精度和计算效率都有明显提高,且在数...     

星载激光雷达气溶胶数据辅助的近岸浑浊水体大气校正研究

提出了一种星载激光雷达CALIOP气溶胶数据辅助的MODIS/Aqua水色数据大气校正方法,并在长江口及其邻近浑浊水体区域进行了实验。通过与实测光谱数据的对比分析说明,本文方法能在一定程度上避免如近红外波段离水辐亮度为零的假设的不合理性,摆脱对实测数据的依赖,有效地反演离水辐亮度,修复SeaDAS软件中短波红外-近红外联合大气校正算法中短波红外波段引起的产品的条带问题。     

基于XML和FLEX的河口海岸数据服务平台

探讨使用长江口的河口海岸数据,提出一套数据结构标准和服务框架,构建一个具有多源数据统一集成管理,适用于本地存储及网络呈现的数据服务平台。基于XML技术通过数据库实现数据的集中存储管理,基于FLEX通过WebGIS实现各种数据在线管理,从而提供一个具有统一的组织结构的综合数据管理服务的解决方案,给长江口的河口海岸的学科基...