New data on Early Cretaceous odonatans (Stenophlebiidae,Aeschnidiidae) from northern China

Liaostenophlebia yixianensis gen. et sp. nov., a new stenophlebiid damsel-dragonfly, is described from the Lower Cretaceous Yixian Formation of western Liaoning, northern China. It is the third Chinese damsel-dragonfly belonging to the family Stenophlebiidae to be described. Liaostenophlebia gen. nov. differs from the other genera of Stenophlebiidae in having Ax2 shifted just above MAb, a transverse and narrow Hal, a more curved anterior side of the hypertriangle, and a broader cubital-anal area. Sinostenophlebia zhanjiakouensis Hong, 1984 was previously attributed to Stenophlebiidae and hardly compares with other genera within this family. A check of the plates of the type species (Sinostenophlebia zhanjiakouensis Hong, 1984) suggests that Sinostenophlebia Hong, 1984 should be a member of the family Aeschnidiidae and it is very likely that this genus is a junior synonym of Leptaeschnidium Pritykina, 1977. The new data increases the diversity of both Stenophlebiidae and Aeschnidiidae in the Lower Cretaceous of China.     

Tourmalinite from northern Guangxi,China

The extensive development of tourmalinite is a feature that distinguishes the northern Guangxi polymetallic tin province of China from similar metallogenic provinces elsewhere. Two types of tourmalinite occur in the province. The first type, in the lower part of the Early Proterozoic Sibao Group, is bedded, stratiform or lenticular tourmalinite that shows well-developed laminated, gel, and degelatinized structures. Its mineral assemblage is very simple and the grain size ranges from 2 to 8 m. This tourmaline is relatively rich in Mg, with an Fe/(Fe + Mg) ratio of 0.25–0.50.The second type of tourmalinite occurs as lodes distributed in the exocontact zone of Late Proterozoic biotite-granite intrusions. Its mineral assemblage is relatively complex; the tourmaline is present as euhedral or subhedral crystals ranging from 0.1 to 3.5 mm, mostly from 0.5 to 1 mm. This tourmaline commonly exhibits a radiating, zoned structure with Fe/(Fe + Mg) ratios of 0.64–0.79. It is suggested that the bedded tourmalinite formed by exhalation in an Early Proterozoic spreading-ridge environment, whereas the vein tourmalinite formed in a plate-convergence setting genetically associated with emplacement of Late Proterozoic biotite granite. As the tourmalinites themselves are related to mineralized rocks and orebodies, their origin and the related boron cycle of the region reflect to some extent the formation and evolution of the associated polymetallic tin deposits of the region.     

1998—2007年新疆植被覆盖变化及驱动因素分析

利用1998-2007年SPOT VGT归一化植被指数(NDVI)数据对新疆植被覆盖的年际和空间变化进行了动态监测,并从气候变化和人类活动双重角度分析了植被覆盖演变的原因.1998-2007年新疆植被覆盖变化经历了2个阶段:1998-2001年植被覆盖严重退化时期;2002-2007年植被覆盖由急剧上升到缓慢下降再到持续升高时期,NDVI明显高于20世纪末期水平.新疆植被覆盖变化存在显著的空间差异,阿尔泰山地森林、巴音布鲁克草原等自然植被NDVI明显退化,农业灌溉区和生态建设地区的植被覆盖明显提高.从不同的土地利用类型来看,沙地和耕地的NDVI上升趋势显著,林地和草地植被的NDVI退化严重.研究表明,新疆植被覆盖变化是气候变化和人类活动共同作用的结果.温度对植被覆盖变化的影响表现为对植被生长年内韵律的控制和春季植被生长期的延长,年降水量的波动式下降是导致新疆植被覆盖变化呈现2个阶段的主导冈素.农业生产水平的提高是新疆农业灌溉区NDVI不断上升的重要原因,同时,近年来大规模实施的生态建设工程所带来的生态效应正在呈现.     

Cenozoic development of northern Svalbard based on thermochronological data

Northern Svalbard represents a basement high surrounded by the Norwegian‐Greenland Sea/Fram Strait, Eurasian Basin, the Barents Shelf and the onshore Central Tertiary Basin (CTB). Published apatite fission track (AFT) data indicate Mesozoic differential, fault‐controlled uplift and exhumation of the region. Thermal history modelling of published and new AFT and (U–Th–Sm)/He ages of 51–153 Ma in the context of regional stratigraphy and geomorphology implies at least two, possibly three, uplift and exhumation stages since late Mesozoic, separated by episodes of subsidence and sediment deposition. Late Cretaceous/Palaeocene exhumation and subsequent burial appear to be related with the transition of compressional to transpressional collision of Svalbard and Greenland during the Eurekan Orogeny. Renewed exhumation since the Oligocene probably results from passive margin formation after the separation of Svalbard and Greenland, when a new offshore sedimentary basin opened west of Svalbard. Final uplift since the Miocene eventually re‐exposed the palaeosurface of northern Svalbard.     

Vegetation change detection from NOAA polar orbiting satellites

A Method is proposed for detecting vegetation change using global area coverage data from the NOAA-7 Advanced Very High Resolution Radiometer. Other methods of vegetation change detection, such as baseline images, are discussed, but not demonstrated. Vegetation Change Detection Images are produced by combining three separate weekly composites of Channel 2 minus Channel 1 AVHRR data. This compositing method takes the highest value of the differenced data for each week period and each pixel location. Three such weekly composites red imaged by individual red, green and blue CRT color guns respectively and then combined to form a color composite. The Vegetation Change Detection Image has 20 km resolution. It can be used to show an entire continent on a single image when the data point to CRT pixel ratio is 1:1. The vector vegetation change (magnitude and direction) is depicted by the color pattern resulting from the relative amount of red, green and blue placed in the pixel due to the individual weekly color composites. If there is no greenness change at a pixel location the amount of red, green and blue will be the same and a gray scale color results. The VCDI could provide a timely first alert for identifying regional and global agricultural changes.Doubts have been expressed about the reliability of this satellite data because of the unknown (and variable) effects of atmospheric attenuation. A basic qualitative rather than quantitative analysis of the data has been suggested as the correct approach.     

Vegetation history of a polygonal peatland, northern, Yukon

Pollen, macrofossils and matrix composition are described for a 221 cm core from a polygonal peatland overlying a late-Wisconsin lakebed. A hydroseral succession of wetland communities occurred at the site, and included a submerged assemblage with Chara , a Carex aquatilis - Eleocharis marsh, a fen, and finally a Sphagnum - Ledum bog. A transition about 9,600 B.P. to a wetter S. balticum - Andromeda carpet is attributed to formation of permaforst and polygonal ice wedges. This community, sometimes with S. compactum and Chamaedaphne , prevailed until about 3,000 B.P. when the polygon became high centered, and peat growth declined. Peat growth rate is determined from 11 ¹⁴C dates, and is used to calculate pollen influx. Apparent periodic oscillations every 2,000 years, in total influx, are not accepted as sufficient evidence of treeline fluctuations.     

Vegetation and climate change in southeastern Madhya Pradesh during Late Holocene,based on pollen evidence

Pollen analysis of 2 m deep sediment core from Kiktiha swamp, Shahdol district has revealed that between 1600 and 700 yr BP, tropical deciduous Sal forests comprising Shorea robusta (Sal), Madhuca indica, Terminalia, Lagerstroemia, Aegle marmelos flourished in the region under a warm and moist climate. Between 700 and 300 yr BP the deciduous Sal forests were succeeded by mixed deciduous forests, which turned sparse and less diversified, reflecting a relatively less moist climate attributed to the weak SW monsoon. The unfavourable climate also adversely affected the agricultural practice as evidenced from the diminution of Cerealia and other culture taxa. Since 300 yr BP onwards the modern deciduous Sal forests were re-established with the timely arrival of active SW monsoon. The increase in Cerealia and culture taxa indicates agricultural prosperity.     

藏北双湖地区三叠纪地层新资料

在西藏北部双湖江爱达日那地区新发现一套出露较完整的三叠纪地层体，从多重地层的角度阐述了三叠系各组级岩石地层单位的基本特征。通过剖面测制，获取了丰富的三叠系地层、沉积相和古生物化石资料，尤其是下三叠统硬水泉组生物扰动灰岩、鲕粒灰岩、豆粒灰岩和中三叠统康南组舍菊石灰岩的发现，为羌塘盆地三叠系地层、沉积相划分与对比，生物古地理研究和沉积盆地分析提供了重要的基础性资料。根据岩石类型和生物组合等特征，将上三叠统土门格拉群含煤系地层划分为3个组级岩石地层单位：红水沟组、石门关组和江爱达日那组。     

The 1998 Flood on the Yangtze, China

This paper examines the main causes ofthe 1998 flood on the Yangtze and addresses a numberof issues related to the exploitation of naturalresources and counter-measures to the flood hazard.The records show that both the amount of precipitationover the catchment and the floodwater discharge fromthe upper basin did not exceed the historical maximum,but water levels in the middle basin were recordedmuch higher than the historical maximum. Humanactivities have greatly increased the risk of theflood hazard. Extensive reclamation of the lakes andfluvial islands in the middle basin has considerablyreduced the floodwater storage and drainage capacityof these natural landscapes of the Yangtze Basin.Deforestation in the catchment area has induced soilerosion, resulting in a large amount of sedimentdeposited in reservoirs whose storage capacity is thusreduced. Strengthening the flood defence to protectpeople living on the floodplain has raised the waterlevel during the flood. An integrated approach isneeded to produce a balanced management plan that canmeet the financial needs of local people in thecatchment area as well as reduce flood risk to theindustries and urban residents in the middle basin ofthe Yangtze.     

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.     

Vegetation response to rapid climate change in central europe during the past 140,000 yr based on evidence from the Füramoos pollen record

The response of Central European vegetation to rapid climate change during the late Quaternary period (Eemian to Holocene) is assessed by data from the new pollen record of Füramoos, southwestern Germany. This record represents the longest late Quaternary pollen record north of the Alps as currently known. Its high degree of completeness allows detailed correlations with Greenland ice cores and sea-surface temperature records from the North Atlantic. Our data show that if climate deteriorations were not long or severe enough to extirpate refugia of arboreal taxa north of the Alps such as during marine oxygen isotope stage (MIS) 5 (i.e., Würm Stadial A, Stadial B, and Stadial C), reforestation with the onset of warmer conditions in Central Europe occurred on a centennial scale. If arboreal taxa became completely extinct north of the Alps such as during MIS 4 (i.e., Würm Stadial D), several thousand years were necessary for the reimmigration from refugia situated in regions south of the Alps. Thus, Dansgaard-Oeschger interstades (DOIS) 24 to 20 and 15 to 11 are expressed in Central European pollen records, whereas DOIS 19 to 16 are not recorded due to migration lags.     

贺兰拗拉谷北段奥陶系等深流沉积研究

笔者采用野外观察和室内分析相结合的研究方法,分析了贺兰拗拉谷北段桌子山剖面奥陶纪地层的沉积相特征及沉积环境的垂向变化和横向迁移规律。以桌子山剖面奥陶系沉积相研究为基础,采用F ischer图解法,求取了其可容空间的变化曲线。在此基础上,结合沉积相模式,识别出了典型的碳酸盐等深流沉积,建立了贺兰拗拉谷北段奥陶系层序地层学模式,为拗拉谷的存在提供了有力的证据。各层序的水进体系域,应列为该区油气勘探的重要目标层段。     

Vegetation change,erosion risk and land management on the Nullarbor Plain,Australia

 Arid karst landscapes that have been degraded by human activities provide a challenge for rehabilitation and an opportunity to test ideas about the stability and resilience of limestone ecosystems. The Nullarbor Plain is the largest arid karst area in Australia (220 000 km²) and is divided into extensive closed karstic depressions separated by low rocky ridges, while the dominant vegetation is chenopod shrubland. Since European settlement there has been considerable change in the vegetation, with significant reduction in shrub and grass cover over large areas of the plain. These changes are related to a state and transition model of vegetation dynamics which incorporates climatic variability, fire history and grazing pressure from sheep, kangaroos and rabbits. A partial sediment budget using ¹³⁷Cs inventories reveals local and regional patterns of soil redistribution within this arid karst landscape. Rehabilitation of eroded soil in pastoral lands has been accomplished at several sites but is labour intensive and vulnerable to climatic fluctuations. Given the low stock numbers, limited number of people involved, and poor economic returns, it would be sensible to make pastoral activities on the Nullarbor secondary to conservation priorities. This would necessitate a change in land ethic to stewardship, with emphasis on rehabilitation and control of feral animals. Management of increased numbers of visitors to the caves and karst also requires that resource inventories and management plans for each area be drawn up and used. Received: 1 June 1995 · Accepted: 4 December 1995     

Vegetation pattern variation,soil degradation and their relationship along a grassland desertification gradient in Horqin Sandy Land,northern China

The Horqin Sandy Land is one of the most severely desertified regions in northern China. Plant communities and soil conditions at five stages of grassland desertification (potential, light, moderate, severe and very severe) were selected for the study of vegetation pattern variation relating to soil degradation. The results showed that vegetation cover, species richness and diversity, aboveground biomass (AGB), underground biomass, litter, soil organic carbon (C), total nitrogen (N), total phosphorus (P), electrical conductivity, very fine sand (0.1–0.05 mm) content and silt (0.05–0.002 mm) content decreased with the desertification development. Plant community succession presented that the palatable herbaceous plants gave place to the shrub species with asexual reproduction and sand pioneer plants. The decline of vegetation cover and AGB was positively related to the loss of soil organic C and total N with progressive desertification (P < 0.01). The multivariate statistical analysis showed that plant community distribution, species diversity and ecological dominance had the close relationship with the gradient of soil nutrients in the processes of grassland desertification. These results suggest that grassland desertification results in the variation of vegetation pattern which presents the different composition and structure of plant community highly influenced by the soil properties.     

江西五里街地区地磁特征及综合信息找矿预测

赣北五里街地区横跨长江中下游铜钼金铅锌成矿带与江南隆起东段钨锡钼成矿带,区内已发现钨钼矿(化)点4处,铜铅矿矿点1处及锡石(褐铁矿)化点1处,显示出良好的找矿前景。本文通过在五里街地区开展1∶5万地面高精度磁法测量工作,厘定了第四系覆盖区横山花岗岩体隐伏边界范围,并利用剩余重力异常数据三维人机交互反演了该岩体深部形态;以磁异常为主,识别出了不同的构造边界(断裂带或不同岩性侵入接触界线)及环形蚀变砂岩带;以地质为基础,将磁异常与化探水系沉积物综合异常进行对比研究,根据异常套合情况,有效地缩小了找矿范围,提高了矿产地质调查效率。根据大比例尺地、物、化示矿信息,指出了五里街地区寻找铜钼金等多金属矿的靶区,为该区后续开展找矿地质工作提供了重要依据。     

The sources of geogenic arsenic in aquifers at Datong basin,northern China: Constraints from isotopic and geochemical data

Mineralogical, geochemical and zircon U–Pb dating studies were carried out to identify the sources of arsenic in the shallow aquifers of Datong Basin in northern China. A sediment sample from 18 m depth containing 10.3 mg/kg arsenic showed a Zircon U–Pb concordant age of 2528 ± 20 to 271 ± 4 Ma that can be divided into two groups (2528 ± 20 to 1628 ± 21 Ma and 327 ± 4 to 271 ± 4 Ma) and is comparable to that of the sedimentary rocks of Taiyuan (upper Carboniferous) and Shanxi Formation (lower Permian) outcropping to the west of Datong Basin. In contrast, a sediment sample from 22.5 m depth containing 5.7 mg/kg arsenic displayed a Zircon U–Pb concordant age ranging from 2561 ± 21 to 1824 ± 26 Ma that is comparable to that of the Hengshan Complex (Ne-Archaean Precambrian) outcropping to the east of .     

藏北羌塘中部戈木错盆地石制品的初步研究

藏北羌塘盆地腹地戈木错周围发现大量石制品,主要为细石核、细石叶、石片和石器,未发现大型打制石器和磨制石器。通过对石制品表面特征的观察,没有发现流水磨损的痕迹,认为这些石制品未经过后期搬运,为原地堆积。对石制品的初步研究表明,戈木错遗址的石制品主要为细小石器,使用的原料主要有硅质岩、玛瑙和燧石。将戈木错的细石器与藏北其他地点的细石器进行对比分析,发现其文化特征与藏北双湖、申扎等地具有一定的相似性,这说明藏北细石器基本属于相同的文化背景,有相同的起源,属于中国北方细石器文化的一部分。此外,从石制品的组合、加工技术特征及对环境的适应过程来看,其时代可能属于新石器时代早期。     

Aeolian processes and landscape change under human disturbances on the Sonid grassland of inner Mongolian Plateau,northern China

Based on remote sensing monitoring, observations and experiments in wind tunnel and field, aeolian processes and landscape change of the Sonid grassland of Inner Mongolia Plateau in northern China were explored in this paper. Aeolian process was very strong and seriously affected by human disturbances on the Sonid grassland of Inner Mongolia Plateau. Sand transport rate of grassland increased quickly with the increase of desertification severities, especially at the very severe desertification stage of sand sheet emergence. Human disturbances can seriously destroy balanced-state soil surface to induce new soil wind erosion over and over again, in particular at the higher wind speeds. Spatial variation of wind erosion was strongly related to land use/cover change, and finally led to landscape change, while emergence of erosional bare patches might be the key link, especially around herdsmen’s settlements and along roads or fences. Avoiding grazing before windy season is very important for decreasing soil wind erosion, not only to protect vegetation cover, but also to reduce trampling-inducing destruction of the soil surface structure. Prohibition of overgrazing must be strictly obeyed under any possible climate conditions, and reclamation should be more careful. Reducing human disturbances by selective emigration and eco-compensation mechanism would be considered as a priority for reducing local wind erosion.     

藏北羌塘中部戈木错盆地石制品的初步研究

藏北羌塘盆地腹地戈木错周围发现大量石制品,主要为细石核、细石叶、石片和石器,未发现大型打制石器和磨制石器。通过对石制品表面特征的观察,没有发现流水磨损的痕迹,认为这些石制品未经过后期搬运,为原地堆积。对石制品的初步研究表明,戈木错遗址的石制品主要为细小石器,使用的原料主要有硅质岩、玛瑙和燧石。将戈木错的细石器与藏北其他地点的细石器进行对比分析,发现其文化特征与藏北双湖、申扎等地具有一定的相似性,这说明藏北细石器基本属于相同的文化背景,有相同的起源,属于中国北方细石器文化的一部分。此外,从石制品的组合、加工技术特征及对环境的适应过程来看,其时代可能属于新石器时代早期。     

藏北南羌塘孜狮桑地区早三叠世牙形刺化石新资料

笔者在藏北开展1∶25万帕度错幅区域地质调查过程中,在达杂迪扎错北面孜狮桑测制地层剖面时发现了产早三叠世牙形刺化石图版Ⅰ)的地层,并新建立了孜狮桑组。孜狮桑位于羌塘盆地中央隆起带[1]的南边,地层区划隶属于羌塘-保山地层区多玛地层分区。孜狮桑组地层层序如下图1)。上覆地层:新进纪康托组紫红色中层砂质砾岩不整合6.灰黑色薄层亮晶砂灰岩59.89m5.灰白色中层含硅质结核细晶白云质灰岩57.18m4.灰白色、灰黑色薄层含生物碎屑亮晶砂屑灰岩27.25m3.灰黑色薄层泥晶灰岩,产牙形刺Neospathodus hom eri,Prio-niodella ctenoides,H ibbardel…