Morphometric and geological conditions for sediment accumulation in the Udava River,Outer Carpathians,Slovakia

The accumulation of sediment in river channels is a phenomenon that is not only influenced by the channel morphology, but also by the physical and geographical characteristics and the endogenous and exogenous processes taking place in the catchment. This paper presents an analysis of the impact the changes in lithological conditions have on the morphological and morphometric parameters of the Udava River channel and their relation to the channel accumulation forms representative of the river’s longitudinal profile as well as of its planform. Results document when accumulation forms occur and what is their spatial distribution within the longitudinal and cross-sectional river profiles. More resistant structures created sections with a lower degree of sedimentation, while in depression segments the degree of sedimentation was higher. With the increase in longitudinal slope, the impact of channel width on the average channel bar size increased. Also a difference in the accumulation was observed between the left and right bank which could be possibly explained by the impact of Coriolis force.     

我国近五年GIS研究状况分析——基于CiteSpace计量分析

检索了CNKI期刊数据库中18种地理信息系统(GIS)相关学术期刊,从中选取2011—2015年间与GIS相关的421篇高被引论文作为研究对象,运用文献计量方法并借助信息可视化软件CiteSpace探讨我国这5年来GIS发展的研究热点、前沿方向以及期刊、作者、研究区域和研究机构的分布特点,为我国GIS领域的研究方向和研究思路提供借鉴和参考。结果表明:空间格局、空间分布、遥感、空间分析、移动GIS、WebGIS、三维GIS和土地利用是GIS研究的热点方向;云南、江西、广西、青海、西藏、宁夏等冷门区域的研究价值有待挖掘;大数据方面的研究兴起于2014年,已然成为GIS研究的前沿方向。     

青藏高原草地土壤有机碳库及其全球意义

定量分析了青藏高原各类草地0～0.65m深度范围内有机碳储量,结果表明:青藏高原总面积为1.6027×10hm²的草地有机碳量达到335.1973×10⁸tC,其中以高原草甸土和高原草原土有机碳积累量为主,两者之和达到232.36×10⁸tC,占全国土壤有机碳量的23.44%,是全球土壤碳库的2.4%.在有机碳储量分析的基础上,按土壤碳释放的两种主要途径:土壤呼吸作用和土地利用方式变化与草地退化,对草地土壤碳排放进行了估算,揭示出青藏高原草地土壤通过呼吸每年排放的CO₂达到11.7×10⁸tC·a^-1,约占中国土壤呼吸总量的2.3%,明显高于全国乃至全球平均值;近30a来,青藏高原草地土壤由于土地利用变化和草地退化所释放的CO₂估计约有30.23×10⁸tC.保护青藏高原草地对于全球变化意义重大.定量分析了青藏高原各类草地0～0.65m深度范围内有机碳储量,结果表明:青藏高原总面积为1.6027×10hm²的草地有机碳量达到335.1973×10⁸tC,其中以高原草甸土和高原草原土有机碳积累量为主,两者之和达到232.36×10⁸tC,占全国土壤有机碳量的23.44%,是全球土壤碳库的2.4%.在有机碳储量分析的基础上,按土壤碳释放的两种主要途径:土壤呼吸作用和土地利用方式变化与草地退化,对草地土壤碳排放进行了估算,揭示出青藏高原草地土壤通过呼吸每年排放的CO₂达到11.7×10⁸tC·a^-1,约占中国土壤呼吸总量的2.3%,明显高于全国乃至全球平均值;近30a来,青藏高原草地土壤由于土地利用变化和草地退化所释放的CO₂估计约有30.23×10⁸tC.保护青藏高原草地对于全球变化意义重大.     

渤海湾北岸Bg10孔磁性地层研究及其构造意义

对渤海湾北岸孔深600m的Bg10孔进行了详细的沉积学和古地磁研究,划分了39个沉积单元;基于516个样品(60个交变样品,456个热退样品)分离出的特征剩磁,建立了钻孔的磁性地层,并与标准极性年表相对比,确定正极性N1、N2、N3、N4、N5、N6和N7分别对应C1n、C1r.1n、C2n、C2r.1n、C2An.1n、C2An.2n和C2An.3n,R1、R2、R3、R4、R5和R6分别对应C1r.1r、C1r.2r+C1r.3r、C2r.1r、C2r.2r、C2An.1r和C2An.2r。钻孔B/M界限埋深162.3m,M/G界限埋深为475.8m,钻孔底部位于C2An.3n内,其年龄应小于3.596Ma。Bg10孔包括3个沉积阶段:Ⅰ阶段为3.3~3.6Ma,沉积速率略大于130m/Ma,为构造活动期,唐县期夷平面结束后,盆地沉降和山体隆升的差异增大,并与西部地区的青藏运动A幕相对应;Ⅱ阶段为1.9~3.3Ma,沉积速率为112m/Ma,为盆地的填充过程,气候变化控制沉积过程,但沧县隆起和黄骅坳陷之间沉降仍有差异。Ⅲ阶段为0~1.9Ma,沉积速率为202m/Ma,约在1.0~1.2Ma发生一期构造活动,与西部地区的昆黄运动时代大体相当。1.0Ma以来,沉积过程受构造和气候变化双重影响,沧县隆起和黄骅坳陷之间仍有差异沉降。唐山-邢台断裂带可能在1.9Ma之后活动性增强,并和张家口-蓬莱断裂带在沧县隆起上的交汇区域形成一个次级凹陷。     

Surface effects of triggered fault slip on Reykjanes Peninsula, SW Iceland

Three large earthquakes (M_w>4.5) were triggered within 5 min, 85 km west of a M_w 6.5 earthquake in the South Iceland Seismic Zone (SISZ). We report on surface effects of these triggered earthquakes, which include fresh rupture, widespread rockfall, disrupted rockslides and block slides. Field data confirm that the earthquakes occurred along N-striking right-lateral strike-slip faults. Field data also support the conclusion from modeling of InSAR data that deformation from the second triggered event was more significant than for the other two. A major hydrological effect was the draining of water through an open fissure on a lake bed, lowering the lake level by greater than 4 m. Field relationships suggest that a component of aseismic slip could have been facilitated by water draining into the fault zone.     

Kanonaite, (Mn 0.76 3+ Al0.23Fe 0.02 3+ )[6]Al[5][O¦SiO4], a new mineral isotypic with andalusite

Kanonaite forms rare porphyroblasts up to 12mm long in a gahnite— Mg-chlorite — coronadite — quartz schist occurring near Kanona, Zambia. The composition is (microprobe analysis): SiO₂ 32.2, Al₂O₃ 33.9, Mn as Mn₂O₃ 32.2, Fe₂O₃ 0.66, ZnO 0.13, MgO 0.04, BaO 0.04, TiO₂ 0.01, CaO 0.01, PbO 0.01, CuO 0.01, total 99.21, corresponding to $$\left( {{\text{Mn}}_{{\text{0}}{\text{.76}}}^{{\text{3 + }}} {\text{Al}}_{{\text{0}}{\text{.23}}} {\text{Fe}}_{{\text{0}}{\text{.015}}}^{{\text{3 + }}} } \right)_{1.005}^{\left[ 6 \right]} {\text{AL}}_{1.00}^{\left[ 5 \right]} \left[ {{\text{O}}_{{\text{1}}{\text{.00}}} |{\text{Si}}_{{\text{0}}{\text{.99}}} {\text{O}}_{{\text{4}}{\text{.00}}} } \right]$$ The mineral is greenish black, strongly pleochroic with X(∥a) yellow green, Y(∥b) bluish green, Z(∥c) deep golden yellow, biaxial positive, with 2V = 53°(3°), α = 1.702, β = 1.730, γ = 1.823. Vickers microhardness (100 gram load) ranges between 906 and 1017kp/mm². The structure is orthorhombic, isotypic with andalusite, space group Pnnm, a = 0.7953(2), b = 0.8038(2), c = 0.5619(2) nm, V = 0.3592(1) nm³, a/b = 0.9895(3), c/b = 0.6990(3), S.G.(_x) = 3.395 g/cm³, Z = 4. The strongest X-ray powder lines are (d in nm, I, hkl):0.5669, 100, 110; 0.4590, 75, 011 and 101; 0.3577, 90, 120 and 210; 0.2827, 94, 220; 0.2517, 90, 310 and 112; 0.2212, 83, 320, 122 and 212. Comparison of the intensities of 373 observed X-ray reflections with those calculated for several models of Mn³⁺-distribution indicates octahedral coordination of all or most of the manganese present. Interpretation of magnetic measurements (μ_eff = 3.15B.M. per Mn atom at 25 ° C) indirectly supports octahedral coordination of Mn³⁺. The name of the mineral is for Kanona, a town near the type locality. The name is proposed for the end member Mn^{3+ [6]}Al^[5][O¦SiO₄] and for members of the solid-solution series towards andalusite with octahedral Mn³⁺>Al. The presently described mineral may be referred to as aluminian kanonaite.     

渤海湾沿岸晚第四纪地层划分及地质意义

本文以4个钻透上更新统钻孔为例,以岩性和沉积构造为基础,采用“C、微体和孢粉等分析方法,结合气候地层和层序地层学的理论,对渤海湾晚第四纪地层进行了划分,讨论了岩相古地理和新构造特征.渤海湾沿岸晚第四纪地层可以划分为9组地层,自下而上分别为海洋氧同位素5e(MIS5e)、MIS5d、MIS5c、MIS5b、MIS5a、M...     

新疆可可托海地区花岗岩成因的研究

新疆可可托海地区有三种花岗岩,它们形成于造山运动不同阶段:片麻状黑云母花岗岩是海西造山运动早期的产物;似斑状花岗岩形成于海西晚期;二云母花岗岩是印支一燕山期侵入而成。三者的岩石、岩石化学、CMF值和QAP图解、亲合度、微量无素、稀土元素、铅和氧同位素组成等研究表明,它们是陆壳交代重熔成因的一个连续成岩系列。     

High‐Precision,High‐Accuracy Oxygen Isotope Measurements of Zircon Reference Materials with the SHRIMP‐SI

Analytical protocols for SHRIMP‐SI oxygen isotope analysis (δ¹⁸O) of a suite of zircon reference materials (RMs) are presented. Data reduction involved a robust estimate of uncertainties associated with the individual spot as well as for groups where the spot data are combined. The repeatability of δ¹⁸O measurements is dependent on both the analytical conditions and the choice of the primary reference material. Under optimised conditions, repeatability was often better than 0.4‰ (2s) allowing sample uncertainties to be obtained to better than 0.2‰ (at 95% confidence limit). Single spot uncertainty combined the within‐spot precision with the scatter associated with repeated measurements of the primary zircon reference material during a measurement session. The uncertainty for individual spots measured under optimised conditions was between 0.3 and 0.4‰ (at 95% confidence). The analytical protocols described were used to assess a variety of zircon RMs that have been used for geochronology and for which laser fluorination oxygen isotope data are available (Temora 2, FC1, R33, QGNG and Ple?ovice), as well as zircons that have been used as RMs for trace element or other types of determination (Mud Tank, Monastery, 91500, AS57, AS3, KIM‐5, OG1, SL13, CZ3 and several other Sri Lankan zircons). Repeated analyses over nine sessions and seven different mounts show agreement within analytical uncertainty for Temora 2, FC1, R33, QGNG, Ple?ovice and 91500, when normalised to Mud Tank. For existing ion microprobe mounts with these materials, an appropriate δ¹⁸O can be determined. However, care should be taken when using zircons from the Duluth Complex (i.e., FC1, AS57 and AS3) as reference materials as our data indicated an excess scatter on δ¹⁸O values associated with low‐U zircon grains.