华夏陆块钠质高镁玄武岩地球化学特征及地质意义

赣州盆地位于钦杭(钦州—杭州)结合带南侧华夏陆块西部,由晚白垩世早期红色碎屑沉积岩系组成,其底部夹有一套玄武岩,全岩Si O_2含量为46.50%~48.13%,具有钠质高镁特征(Mg O=15.47%~18.24%,Mg~#=74~77,K_2O/Na_2O=0.22~0.39)。稀土元素配分型式表现出轻稀土富集右倾,没有明显的Eu异常的特点,表明岩浆没有明显的斜长石分离结晶作用;微量元素上富集大离子亲石元素,高场强元素特别是Ta、Nb、Ti亏损不明显,Cr、Ni的含量分别为235×10~(-6)~617×10~(-6)、157×10~(-6)~493×10~(-6),与原生岩浆的Cr、Ni含量接近,Ba/Nb值(13.51~23.18)和La/Nb值(0.82~1.03)表明源区有富集地幔组分;Sr—Nd—Pb—O同位素显示出源区性质具有EMⅡ型富集地幔特征。岩石学和地球化学特征表明,玄武岩具有原生岩浆性质,是富集地幔部分熔融的产物。同时为中生代华夏陆块EMⅡ型岩石圈地幔提供了准确的证据。由赣州盆地晚白垩世构造背景和构造环境判别图解可知,本区玄武岩形成于板内拉张环境,可能与古太平洋俯冲条件的转变有关。     

黄河口凹陷莱北斜坡带玄武岩发育区砂岩成岩特征、孔隙流体及储层控制因素

为探究黄河口凹陷研究区玄武岩喷发对相关砂岩储层成岩作用的影响,从粘土矿物、沸石及微量元素分析入手,明确莱北斜坡带古近系不同层位孔隙流体性质变化,建立火成岩发育区砂岩储层的成岩-孔隙演化模式：沙一段和沙二段沉积时期,受小规模玄武岩喷发与干旱-半干旱气候条件下碱性水介质影响,砂岩中钠长石化和碳酸盐岩胶结普遍,碎屑颗粒表面发育白云石膜,见石英溶蚀现象;东三段三角洲砂岩储层受沙一段暗色泥岩中析出的卤水及陆源淡水输入影响,叠加后期富铁镁质孔隙水混合影响,成岩作用以弱碱性水介质条件下沸石溶解、粘土矿物转化与钠长石化为主;东一段和东二段沉积时期玄武岩广泛发育,不稳定富铁镁矿物的强烈水解,导致孔隙流体富含铁镁质,以低硅沸石的沉淀与溶蚀为特色。与玄武岩喷发相关的局部沸石沉淀与溶解以及玄武岩喷发形成的“工字型”构架对东营组砂岩孔隙的保存有利;而沙一段和沙二段沉积时期碱性水介质下形成的栉壳状白云石抑制了石英的次生加大,碱性水介质下的石英溶蚀现象普遍,有利于其砂岩孔隙的保存。     

珠江口淇澳岛海岸带反硝化作用研究

采用N2通量法,在一套连续流动培养装置中测定珠江口淇澳岛海岸带的反硝化速率,探讨各种因素对淇澳岛海岸带反硝化速率的影响.结果表明,反硝化速率受NO3-的利用率影响,而不是NO3-的绝对浓度.大型红树植物对淇澳岛海岸带的反硝化速率影响最大,其次是硝酸盐利用率,而有机质含量的影响较小.由于大型红树植物的影响,样品Q0411-5的反硝化速率比同在岛内的Q0411-3高出1倍.样品Q0412-14的NO3-培养前后的浓度变化(△NO3-)是Q0412-9的4倍多,因为受硝酸盐利用率的影响,它的反硝化速率却是Q0412-9的2倍多.温度对反硝化速率的影响程度尚不能确定.     

Large phreatomagmatic vent complex at Coombs Hills, Antarctica: Wet, explosive initiation of flood basalt volcanism in the Ferrar-Karoo LIP

The Mawson Formation and correlatives in the Transantarctic Mountains and South Africa record an early eruption episode related to the onset of Ferrar-Karoo flood basalt volcanism. Mawson Formation rocks at Coombs Hills comprise mainly (≥80% vol) structureless tuff breccia and coarse lapilli tuff cut by irregular dikes and sills, within a large vent complex (>30 km²). Quenched juvenile fragments of generally low but variable vesicularity, accretionary lapilli and country rock clasts within vent-fill, and pyroclastic density current deposits point to explosive interaction of basalt with groundwater in porous country rock and wet vent filling debris. Metre-scale dikes and pods of coherent basalt in places merge imperceptibly into peperite and then into surrounding breccia. Steeply dipping to sub-vertical depositional contacts juxtapose volcaniclastic rocks of contrasting componentry and grainsize. These sub-vertical tuff breccia zones are inferred to have formed when jets of debris + steam + water passed through unconsolidated vent-filling deposits. These jets of debris may have sometimes breached the surface to form subaerial tephra jets which fed subaerial pyroclastic density currents and fall deposits. Others, however, probably died out within vent fill before reaching the surface, allowing mixing and recycling of clasts which never reached the atmosphere. Most of the ejecta that did escape the debris-filled vents was rapidly recycled as vents broadened via lateral quarrying of country rock and bedded pyroclastic vent-rim deposits, which collapsed along the margins into individual vents. The unstratified, poorly sorted deposits comprising most of the complex are capped by tuff, lapilli tuff and tuff breccia beds inferred to have been deposited on the floor of the vent complex by pyroclastic density currents. Development of the extensive Coombs Hills vent-complex involved interaction of large volumes of magma and water. We infer that recycling of water, as well as recycling of pyroclasts, was important in maintaining water supply for phreatomagmatic interactions even when aquifer rock in the vent walls lay far from eruption sites as a consequence of vent-complex widening. The proportion of recycled water increased with vent-complex size in the same way that the proportion of recycled tephra did. Though water recycling leaves no direct rock record, the volcaniclastic deposits within the vent complex show through their lithofacies/structural architecture, lithofacies characteristics, and particle properties clear evidence for extensive and varied recycling of material as the complex evolved. Editorial responsibility: J. Donnelly-Nolan     

卫星红外遥感技术在我国环保领域中的应用与发展分析

本文较为系统地分析了卫星红外遥感技术在我国秸秆焚烧、沙尘、气溶胶、颗粒物、灰霾等大气环境遥感监测,水华、水质参数、水表温度、热污染、核电厂温排水等水环境遥感监测,以及土壤含水量、地表温度、干旱、城市热岛效应等生态环境遥感监测的应用。同时,指出目前国产卫星红外载荷业务化应用程度不高、辐射定标能力不足、应用反演算法原创性不强、地面观测和试验验证能力不足等问题;并提出需大力发展国产红外传感器、提高辐射定标能力、发展国内原创监测算法、建设大型环保应用综合试验场等建议,以促进红外遥感技术在环境保护领域的应用和发展。     

基于自动站观测资料的深圳城市热岛研究

利用103个自动站气温观测资料,对深圳的城市热岛现象进行了研究.分析表明:1)高速的城市化进程造成自动站周边下垫面属性的变化,对气温造成了显著影响,这种影响即使是在仅仅10年内也表现得较为明显.2)由于深圳地处海滨,深圳的近地层气温分布是海陆作用叠加城市热岛效应形成的结果.按照传统定义的深圳城市热岛,其空间分布在不同季...     

不同类型冷却屋顶方案对城市群热环境的缓解效果

利用耦合单层城市冠层模型的中尺度数值模式WRF/UCM,选取8组不同反照率和绿化比例的屋顶冷却方案进行敏感性试验,模拟研究不同冷却屋顶方案对长三角城市群2013年夏季城市热环境的影响,并分析其影响机制.结果表明:不同冷却屋顶方案对城市群热环境的缓解效果与屋顶参数之间呈很强的线性关系.高温热浪天气下,H R 4(反照率为...     

上海近50年气温变化与城市化发展的关系

根据上海地区2个气象站近50年的年均气温数据,采用回归分析、滑动平均和Mann\|Kendall检验法研究上海地区气温的年代际变化与跃变,城郊温差的年际变化;采用趋势拟合与相关分析,研究城郊温差与城市人口、GDP、能源消耗量、建成区面积和住宅竣工面积等各项城市发展指标的关系.结果表明：（1）近50年来,上海地区年均气温缓慢上升,20世纪90年代后城郊温差呈锯齿状上升趋势,若以徐家汇代表城区,奉贤代表郊区,则近50年来,城郊温差增温率为0.23℃/10a.（2）1989~1990年为上海城区气温的跃变年份,而郊区的气温跃变出现在20世纪90年代中期.（3）各项城市发展指标均与上海城郊温差有着显著的相关性,表明它们与上海城市热岛的发展关系密切,其中,住宅建设是上海城市热岛最主要的驱动因素,城市人口和经济发展也具有重要影响.     

Stratigraphy and sedimentation rates of Upper Cretaceous deep-water systems of the Rhenodanubian Group (Eastern Alps, Germany)

In the Bavarian Alps (Germany), west of the Isar River, the abyssal deposits of the Lower Barremian to Upper Campanian Rhenodanubian Group consist of siliciclastic and calcareous turbidites alternating with hemipelagic non-calcareous mudstones. The up to 1500-m-thick succession, deposited in the Penninic Basin to the south of the European Plate, is characterized by a low mean sedimentation rate (c. 25 mm kyr⁻¹) over 60 million years. Palaeocurrents and turbidite facies distribution patterns suggest that sedimentation occurred on a weakly inclined abyssal plain. The highest sedimentation rates (up to 240 mm kyr⁻¹) were associated with the calcareous mud turbidites of the newly defined Röthenbach Subgroup, which includes the Piesenkopf, Kalkgraben and Hällritz formations (Middle Coniacian to Middle Campanian). These calcareous turbidites prograded from the west, and interfinger towards the east with red hemipelagic claystone. A high sea level presumably favoured pelagic carbonate production and accumulation on the shelves and on internal platforms in the western part of the basin, whereas siliciclastic shelves with steep slope angles have bordered the eastern part of the basin, where a dearth of turbidite sedimentation and increased Cretaceous oceanic red beds deposition occurred. In contrast to the eustatically-induced Middle Coniacian to Lower Campanian Cretaceous oceanic red beds (calcareous nannoplankton zones CC14 to CC18), red hemipelagites of Early Cenomanian age (upper part of calcareous nannoplankton zone CC9) and early Late Campanian age (upper part of zone CC21 and zone CC22) are interpreted as the result of regional tectonic activity.     

Preliminary geochemical study of volcanic rocks in the Pang Mayao area, Phrao, Chiang Mai, northern Thailand: tectonic setting of formation

The least-altered, Permian mafic volcanic rocks from the Pang Mayao area, Phrao District, Chiang Mai Province, part of Chiang Rai–Chiang Mai volcanic belt, have been analyzed and are found to be mid-ocean ridge and ocean–island basalts. The mid-ocean ridge basalts occur as lava flows or dike rocks. They are equigranular, fine- to medium-grained and consist largely of plagioclase, clinopyroxene and olivine. These basalt samples are tholeiitic, and have compositions very similar to T-MORB from the region where the Du Toit Fracture Zone intersects the Southwest Indian Ridge. The ocean–island basalt occurs as pillow breccia, and lava flows or dike rocks. They are slightly to moderately porphyritic, with phenocrysts/microphenocrysts of clinopyroxene, olivine, plagioclase and/or Fe–Ti oxide. The groundmass is very fine-grained, and made up largely of felty plagioclase laths with subordinate clinopyroxene. These basalt samples are alkalic, and chemically analogous to those from Haleakala Volcano, Maui, Hawaiian Chain. These mafic volcanic rocks may have been formed in a major ocean basin rather than in a mature back-arc basin.