A contrast of two typical LUCC processes and their driving forces in oases of arid areas: A case study of Sangong River Watershed at the northern foot of Tianshan Mountains

Aerial photographs taken in 1978 and 1987, Landsat TM images in 1998 as well as soil, hydrology and socio-economic data for the oases in Sangong River Watershed were processed by Remote Sensing (RS) and Geographic Information System (GIS). There are two typical agricultural land uses in oases, Farm-based Land Use with large-scale intensified agricultural activities (FLU) and Household Responsibility-based Land Use with small-scale activities (HRLU). The Index Model of Land Use/Land Cover Change (LUCC), Weighted Index Sum (WIS) and logistic stepwise regression model were established to contrast the two typical LUCC processes and their driving forces. The land use patterns were dominated by cropland and grassland for the entire region, and cropland, residential and industrial land were increasing stably. In the HRLU areas, woodland and grassland declined dramatically, but in the FLU areas, grassland decreased only by 12.0%, whereas woodland increased by 13.7%. LUCC was stronger in the earlier stage (1978–1987) than in the later stage (1987–1998) for the entire region. LUCC was more intense in the HRLU areas than in the FLU areas during the entire period (1978–1998). Policy was a key factor in the land use change, and water resources were a precondition in land use. Under the control of policy and water resources, the main human driving factors included population and economy, and the main natural restrictions were soil fertility and groundwater depth. Human driving factors controlled the land change in the HRLU areas, but natural restriction factors dominated in the FLU areas. In the mean time, intensification of LUCC in the region had some spatiotemporal implications with a fluctuation of impact factors.     

Noble metals in the insoluble carbonaceous substance of black shales and ores: Direct atomic emission data

The way of extraction of insoluble carbonaceous substance (ICS) from black shales and technique of determination of noble metals (NM) in it by direct arc atomic emission analysis (AEA) were developed. The first results are reported on the determination of mineral-bound noble metals in ICS concentrates, which were extracted from the rocks and ores of the Sukhoi Log, Vernyi, Vasil’evskoe, Kuranakh, Daugyztau, Bakyrchik, Kamennoe, El’dorado, and other deposits.     

末次冰消期晚期青藏高原东北部气候变化

我国最大的内陆封闭湖泊青海湖的沉积岩芯为研究末次冰期/全新世过渡期间青藏高原东北部的环境变化和季风降水演变提供了连续高分辨率环境档案。对两孔岩芯的多学科研究结果表明:大约14000～11600aB.P.期间气候干冷,湖泊的自生碳酸盐和有机质生产率远低于全新世;季节性入湖径流量在11600aB.P.突然增大;从10700aB.P.起,夏季蒸发量突然增大,干旱化作用导致碳酸盐滩湖环境;区域降水量在10000aB.P.的增大结束了滩湖环境,标志了早全新世温暖较湿气候的开始。全新世早期的青海湖水深比现在要浅20m左右,表明那时的有效湿度显然比现在要低很多。14000～10000aB.P.期间青海湖水深不超过6m,说明在末次冰消期的这一时段中,青藏高原东北部没有形成大规模冰融水。在10700～10000aB.P.期间突发的干旱事件与西欧的新仙女木事件(YoungerDryas)年代相当,但没有气候变冷的证据。青藏高原东北部末次冰消期的气候变化表现了明显的阶段性特征和有效湿度的突然改变。区域季风降水量和夏季温度的变化决定了该过渡期的这种变化格局。     

Bericht über die Versammlung der Geologischen Vereinigung am 24.–26. Sept. 1924 in Innsbruck

Ohne Zusammenfassung     

Use of remote sensing in lineament analysis for tectonic evolution and resource study of a part of Vindhyan Basin,Jhalawar area,India

Synoptivity and the exemplified fracture systems exhibited by the space borne imagery data has helped in solving many of the geological enigma in various parts of the world. The study conducted, using such remotly sensed data, in Jhalawar anticline, part of Proterozoic Cratonic Vindhyan Basin, Rajasthan, India, led to infer the history of tectonic evolution of peribasinal deformation which has been a matter of controversy for a century and more. In Landsat MSS data the Jhalawar region displays a panorama of lineaments and their analysis through azimuthal frequency diagrams, isofracture, lineament incidence and lineament intersection incidence density maps shows that the mean orientation of the lineaments fall in NW-SE and NE-SW and the shape of the various lineament density contours also show NE-SW and NW-SE orientations. In aerial photographs the area exhibits four sets of lineaments in NE-SW, NW-SE, N-S and E-W directions. Amongst these the former two sets are expressed as wide open master fracture systems with prolific vegetation fills along them and the latter two sets are characteristically observed as thin vegetation linears with frequent strike slip faulting along them. The further analysis of these fracture/lineament systems derived from multi-level remote sensing data shows that the Jhalawar anticline, which followed the pattern of flexural slip fold mechanism, was evolved by horizontally disposed σ1 (greatest principal stress) and 3σ (least principal stress) with the former oriented in NE-SW and the latter aligned in NW-SE directions with vertically disposed 2σ. The inference of such palaeostress environment of the Jhalawar region lead in the identification of a buried rigid basement high southwest of Jhalawar anticline, beneath the Deccan pile and loci of ground water, silica sand and probable igneous plug.     

Climate change and local adaptation strategies in the middle Inner Mongolia,northern China

According to records of 17 meteorological stations distributed in the study area, climate change of the middle Inner Mongolia in northern China was analyzed in this paper. Based on SPOT VGT data, combined with field investigation, local vegetation change was detected in the last 10 years. The results show that annual mean air temperature obviously rose, while precipitation slightly decreased in fluctuation in the study area during the last 50 years. Air temperature increasing rates are +0.318°C 10 year⁻¹ during 1960-2009 and +0.423°C 10 year⁻¹ during 1980–2009, while precipitation decreasing rates are −2.91 mm 10 year⁻¹ during 1960–2009. There were five different dry or wet periods from the 1960s to the 2000s in order, and the wetter 1990s and the drier 2000s changed dramatically in the study area. Local climate totally tend to warm–dry conditions during the last 50 years. According to coefficient of variation (Cv) of yearly growing-season cumulative NDVI value and yearly NDVI maximum in pixel scale, vegetation had experienced huge temporal and spatial variation during the last 10 years. Recently, frequent droughts and dust storms seriously affected local agriculture and grazing activities, and resulted in heavy economic loss, especially over the drought period of 1999–2001. Faced with those drought disasters accompanied with strong dust storms, the local authorities proposed the enclosing-transferring strategy and made great efforts to adapt overt climate change and improve environment, including making selective emigration, decreasing livestock numbers, fencing grasslands and building forage production bases with irrigation instruments and actively adjusting industry structure. However, some effects and potential problems of this adaptation strategy still need to be comprehensively assessed further in longer time scales and aimed at different sub-regions.     

An investigation of earthquake induced pounding between adjacent buildings

The response of adjacent buildings in city blocks to several strong earthquakes is analysed, taking into account the mutual collisions, or pounding, resulting from insufficient or non-existing separation distances. The buildings are idealized as lumped-mass, shear beam type, multi-degree-of-freedom (MDOF) systems with bilinear force-deformation characteristics and with bases supported on translational and rocking spring-dashpots. Collisions between adjacent masses can occur at any level and are simulated by means of viscoelastic impact elements. Using five real earthquake motions the effects of the following factors are investigated: building configuration and relative size, seismic separation distance and impact element properties. It is found that pounding can cause high overstresses, mainly when the colliding buildings have significantly different heights, periods or masses. This suggests a possibility for introducing a set of conditions into the codes, combined with some special measures, as an alternative to the seismic separation requirement.     

Unusual spatial-temporal dynamics of geomagnetic disturbances during the main phase of the extremely strong magnetic storm of November 7–8, 2004

The spatial dynamics of geomagnetic variations and pulsations, auroras, and riometer absorption during the development of the main phase of the extremely strong magnetic storm of November 7–8, 2004, has been studied. It has been indicated that intense disturbances were observed in the early morning sector of auroral latitudes rather than in the nighttime sector, as usually takes place during magnetic storms. The unusual spatial dynamics was revealed at the beginning of the storm main phase. A rapid poleward expansion of disturbances from geomagnetic latitudes of 65°–66° to 74°–75° and the development of the so-called polar cap substorm with a negative bay amplitude of up to 2500 nT, accompanied by precipitation of energetic electrons (riometer absorption) and generation of Pi2–Pi3 pulsations, were observed when IMF B _z was about ?45 nT. The geomagnetic activity maximum subsequently sharply shifted equatorward to 60°–61°. The spatial dynamics of the westward electrojet, Pi2–Pi3 geomagnetic pulsations, and riometer absorption was similar, which can indicate that the source of these phenomena is common.