青藏高原东北缘山地农户对气候变化的感知及适应策略——以湟水中游为例

以青藏高原东北缘山地地区不同海拔高度地理单元村落的农户为调查对象,进行气候变化、气象灾害的感知及适应策略等调查,采用感知强度公式及专家打分法分析农户气候变化感知以及所采用的适应策略,结果显示：1961—2013年湟水中游气候变化整体趋于暖干化,有84%的农户认为气候变暖,并对其生活造成了严重的影响;在不同海拔高度上的地理单元,农户对气象灾害的感知有明显差异,川水地区农户对沙尘的感知最强,浅山地区农户对虫害的感知最强,而脑山地区农户对连阴雨的感知最强;不同海拔高度的农户对适应策略的选择不同,川水地区农户主要采取“生产性+生活性+保障性”组合适应策略;浅山地区农户主要采取“生产性+生活性”组合适应策略;而脑山地区的农户则主要采取单一的“生产性”适应策略来应对气候变化所带来的影响。     

21世纪前期长江中下游流域极端降水预估及不确定性分析

在全球变暖背景下,极端降水的频率、强度以及持续时间均在显著增加,尤其是对于气候变化敏感的长江中下游流域。由于模式本身、温室气体排放情景以及自然变率存在较大的不确定性,因此未来预估变化的不确定性一直备受关注。为了能够得到对于未来极端降水更为准确的预估结果,使用NEX-GDDP（NASA Earth Exchange Global Daily Downscaled Projections）提供的19个CMIP5降尺度高分辨率数据（0.25°×0.25°）,给出21世纪前期（2016—2035年）长江中下游流域极端降水的可能变化。根据长江中下游流域178个气象站1981—2005年的逐日降水量数据,计算了能够代表极端降水不同特征的指数,在评估模拟能力的基础上给出了21世纪前期RCP4.5情景下极端降水的变化。结果表明,降尺度结果对长江中下游流域极端降水有很好的模拟能力,除R90N外,所有模式模拟其余指数的空间结构与观测的相关系数均超过了0.6。其中所有模式模拟PRCPTOT和R10的相关系数均超过0.95。21世纪前期,长江中下游地区降水趋于极端化,尤其是在流域的西部地区。极端降水日数的变化在减少,表明对于极端降水的贡献主要来自于极端降水日的较大日降水量,而非极端降水日数。未来预估不确定性的大值区主要位于流域的南部地区,流域的西部地区不确定性较低,西部地区极端降水的增加应该受到更多的重视。      

九江下蜀黄土的常量元素组成及其物源指示

长江中下游地区下蜀黄土的物质来源一直是个热点问题。本文对江西九江下蜀黄土和甘肃临洮晚更新世以来黄土的常量元素组成进行了研究,并与末次间冰期以来黄土高原其它点位的黄土、长江中下游其它地点的下蜀黄土和长江沉积物的元素组成进行对比,以期探讨九江下蜀黄土的物质来源。结果表明：（1）九江下蜀黄土的地球化学元素以SiO2、Al2O3、Fe2O3为主。与临洮黄土的元素组成相比,九江下蜀黄土具有较高的SiO2、Al2O3、Fe2O3、TiO2含量和较低的CaO、MgO含量。（2）在空间上,下蜀黄土的SiO2/Al2O3比值未表现出黄土高原黄土（北方黄土）的SiO2/Al2O3比值随纬度规律性变化的特点,揭示下蜀黄土的主要源区可能不是北方的内陆荒漠或黄土高原。（3）TiO2/Al2O3-K2O/Al2O3和TiO2/Al2O3-Fe2O3/Al2O3图解显示下蜀黄土与北方黄土存在显著差异,进一步表明下蜀黄土与北方黄土的主要源区可能不同。     

应用粒度成因单元划分高分辨率层序地层基准面旋回

摘要　在Goodwin和Anderson于1985提出的PAC假说基础上,针对目前基准面旋回级别划分较为混乱的状况,将基准面旋回赋予了自旋回和异旋回的涵义,探索性地提出了粒度成因单元的概念和研究方法,并将其应用到柴窝堡盆地中二叠统芦草沟组高分辨率层序地层的研究中,建立了该区中二叠统草沟组高分辨率层序地层格架,划分出了2个长期基准面旋回6个中期粒度成因单元以及5段。     

漠河盆地中侏罗统砂岩地球化学特征及物源属性分析

漠河盆地的中侏罗统.砂岩具有高SiO2、低Fe2O3、FeO 、MgO 和轻稀土元素富集, 重稀土相对亏损,显示弱的负Eu异常的特征.综合分析砂岩的常量元素、微量元素和稀土元素的地球化学特征,经构造判别图解,笔者认为漠河盆地中侏罗统沉积时物源区具有大陆岛弧和活动大陆边缘的构造环境.盆地南侧的额尔古纳地块北缘古生代杂岩可能是盆地的主要物源.     

中天山白石头泉岩体年代学、岩石成因及构造意义

白石头泉岩体位于中天山北缘边界断裂(沙泉子断裂)南侧。该岩体从下至上可分为五个连续过渡的岩相带,即淡色花岗岩(a带),含天河石花岗岩(b带),天河石花岗岩(c带),含黄玉天河石花岗岩(d带)以及黄玉钠长花岗岩(e带),其中,b、c、d和e带均为a带分异的产物。白石头泉岩体的LA-ICP-MS锆石U-Pb定年结果表明,该岩体侵位于早二叠世早期(295.6±1.3Ma),并于印支期(~214Ma)经历了一次热事件的改造。淡色花岗岩在主量元素上富硅(SiO₂= 74.93%~76.18%)、富碱(K₂O + Na₂O=8.07%~8.80%)、富钠(K₂O / Na₂O=0.82~0.89),贫钙、镁,而在微量元素上富Rb、F和Ga(Al/Ga比值为2217~3134),贫Ba、Sr和Eu并具强烈的铕负异常(δEu=0.0020~0.0091),反映出其源区为富含白云母的片岩(或片麻岩),成岩压力较低,温度大于860℃。结合区域地质特征,作者等认为白石头泉岩体形成于相对拉张的构造背景,是中-上地壳源岩经历高温贫水熔融的产物,其形成与幔源岩浆内侵作用有关。     

Role of Quaternary stratigraphy on arsenic-contaminated groundwater from parts of Middle Ganga Plain,UP–Bihar,India

Late Quaternary stratigraphy and sedimentation in the Middle Ganga Plain (MGP) (Uttar Pradesh–Bihar) have influenced groundwater arsenic contamination. Arsenic contaminated aquifers are pervasive within narrow entrenched channels and flood plains (T₀-Surface) of fine-grained grey to black coloured argillaceous organic rich Holocene sediments (Newer Alluvium). Contaminated aquifers are often located close to distribution of abandoned or existing channels and swamps. The Pleistocene Older Alluvium upland terraces (T₂-Surface) made up of oxidized yellowish brown sediments with calcareous and ferruginous concretions and the aquifers within it are free of arsenic contamination. MGP sediments are mainly derived from the Himalaya with minor inputs from the Peninsular India. The potential source of arsenic in MGP is mainly from the Himalaya. The contaminated aquifers in the Terai belt of Nepal are closely comparable in nature and age to those of the MGP. Arsenic was transported from disseminated sources as adsorbed on dispersed phases of hydrated-iron-oxidea and later on released to groundwater mainly by reductive dissolution of hydrated-iron-oxide and corresponding oxidation of organic matter in aquifer. Strong reducing nature of groundwater is indicated by high concentration of dissolved iron (11.06 mg/l). Even within the arsenic-affected areas, dugwells are found to be arsenic safe due to oxyginated nature.     

粗壮假碾磨齿兽的发现及其科学意义

本文简要回顾了蜀兽类哺乳动物的研究历史,论述了在哺乳动物牙齿演化和中生代陆相地层对比研究中的科学意义。粗壮假碾磨齿兽的发现有力地支持了哺乳动物中“三磨楔齿形臼齿趋同演化”的假设,并再一次以直接的化石证据表明内蒙古宁城道虎沟地区含蜀兽类化石地层的时代为中侏罗世。     

Geosites inventory of the northwestern Tabular Middle Atlas of Morocco

Across the northwestern Tabular Middle Atlas of Morocco there are many examples of landscapes, rocks and fossils that provide key evidence of a particular moment or period in Earth history. Such Earth heritage sites are important for educating the general public in environmental matters. They also serve as tools for demonstrating sustainable development and for illustrating methods of site conservation as well as remembering that rocks, minerals, fossils, soils, landforms form an integral part of the natural world. The significance of certain sites for aesthetic or tourism reasons is obvious. There are numerous geosites, which could contribute to effective exploitation of geotourism, often in conjunction with ecotourism. The strategy employed to such sites involves close consultation with all communities in the vicinity of the respective geosite and is not only aimed at tourism and education, but also at sustainable improvement of the infrastructure of the people of this area. Geological heritage sites, properly managed, can generate employment and new economic activities, especially in regions in need of new or additional sources of income.     

New Jurassic Fossil True Bugs of the Pachymeridiidae(Hemiptera:Pentatomomorpha)from Northeast China

Four new fossil genera and species of true bugs from the family Pachymeridiidae, Beipiaocoris multifurcus, Bellicoris mirabilis, Nitoculus regiUus, and Viriosinervis stolidus, are described. New specimens were collected from the Middle and Upper Jurassic non-marine sedimentary strata from the Jiulongshan and Yixian Formations of northeast China. The species Karatavocoris asiatica Becker-Migdisova, 1963, which was considered to be a member of the family Coreidae is transferred to the Pachymeridiidae. A new map of all known and newly discovered fossil pachymeridiid localities is given. The diagnosis of the family is modified.