Imag(in)ing the continental lithosphere

This paper is primarily concerned with seismically imaging details in the mantle at an intermediate scale length between the large scales of regional and global tomography and the small scales of reflection profiles and outcrops. This range is roughly 0.1–1 km < a < 10–10² km, where a is the scale. We consider the implications of several models for mantle evolution in a convecting mantle, and possible scales present in the non-convecting tectosphere. Reflection seismic evidence shows that the structures preserved from continental accretion within and at the margins of the Archean cratons are subduction related, and we use subduction as an analog for scales left by past events. In modern orogenic belts we expect to find subduction structures, small scale upper mantle convection structures, and basalt extraction structures. We examine some of the scales that are likely formed by orogenic processes.We also examine the seismic velocity and density contrasts expected between various upper mantle constituents, including fertile upper mantle, depleted upper mantle, normal and eclogitized oceanic crust, and fertile mantle with and without partial melt. This leads directly to predicting the size of seismic signals that can be produced by specular conversion, and scattering from layers and objects with these contrasts.We introduce an imaging scheme that makes use of scattered waves in teleseismic receiver functions to make a depth migrated image of a pseudo-scattering coefficient. Image resolution is theoretically at least an order of magnitude better than traveltime tomography. We apply the imaging scheme to three data sets from 1) the Kaapvaal craton, 2) the Cheyenne Belt, a Paleoproterozoic suture between a protocontinent and an island arc, and 3) the Jemez Lineament, a series of aligned modern volcanic structures at the site of a Proterozoic suture zone. The Kaapvaal image, although not defining a unique base of the tectosphere, shows complicated “layered” events in the region defined as the base of the tectosphere in tomography images. The image of the transition zone discontinuities beneath the Kaapvaal craton is remarkable for clarity. The migrated receiver function image of the upper mantle beneath the Cheyenne belt is complicated, more so than the tomography image, and may indicate limitations in the receiver function imaging system. In contrast the Jemez Lineament image shows large-amplitude negative-polarity layered events beneath the Moho to depths of 120 km, that we interpret as melt-containing sills in the upper mantle. These sills presumably feed the Quaternary–Neogene regional basaltic volcanic field.     

安徽蒙城九里桥晚更新世古菱齿象化石

文中描述了1981年秋季在安徽蒙城发现的诺氏古菱齿象化石（Palaeoloxodon nau—manni）.首次提供了晚更新世晚期,有14C同位素年龄测定的古菱齿象的确切地点及层位.同时对该类象化石在淮北平原的分布提出一些初步的看法.     

Palaeoceanological significance of Holocene ostracean banks in Tianjin area

On the basis of the study of ostracean banks in Tianjin area, the present study recognized that the ostracean banks at Ninghe County in Tianjin area are well developed along the west coast of the Bohai Sea; they consist of thanato-coenose and taphocoenose from Crassistrea gigars and C. revularis. From the 14C datings it can be known that the banks had formed from early Middle-Holocene and continued up to over 2 ka BP (14C age). The top has different reliefs . Although there is an effect of spatial shift of estuary position, the top is only distributed in the range of-0. 50--2. 50 m(Huanghai elevation minus National elevation system). The banks cannot explain the sea-level fluctuation. As the string ostracean banks are distributed near E-W direction, it suggests that the direction of tidal currents was then similar to that of the present day.     

帕克菲尔德地区圣安德烈斯断层强度变化的远距离影响因素

断层强度是反映孕震区状态的一个基本特性,其时间变化会增大或降低最终触发地震事件的可能性。虽然有人提出断层强度变化能解释各种不同现象,如地震活动的远距离影响,但实际中还没有现场监测这种重要特性的手段。     

对内蒙古东部西拉木伦河南岸上二叠统铁营子组的重新厘定

在首次发现西拉木伦河南岸上、下二叠统之间存在角度不整合面的基础上 ,利用最新资料重新厘定上二叠统铁营子组。在系统分析岩石特征、基本层序特征、古生物化石、沉积构造的基础上 ,确认了其沉积环境为内陆山间河流——湖泊。依据铁营子组与下伏地层及侵入岩的接触关系、采获的植物化石、砾石成分及来源判断 ,其沉积时代为晚二叠世。     

Spatial variations of the 660-km discontinuity in the western Pacific subduction zones observed from CEArray triplication data

We examined the spatial variation of velocity structures around the 660-km discontinuity at the western Pacific subduction zones by waveform modeling of triplication data.Data from two deep earthquakes beneath Izu-Bonin and Northeast China are used.Both events were well recorded by a dense broadband seismic network in China (CEArray).The two events are located at approximately the same distance to the CEArray,yet significant differences are observed in their records:(1) the direct arrivals traveling above t...     

汶川地震灾后人口与居民点空间配置的适宜性评价

The suitability evaluation of population and settlements spatial layout in the mountainous areas is an important basis on which the scale of population and settlement after Wenchuan Earthquake is determined. Based on the statistical data of field research, this paper chooses 1264 towns in 51 counties as the scope of evaluation, selects eight indices in the evaluation index system which includes post-disaster population scale, population density, urbanization rate, the percentage of migrant workers, death rate by earthquake, the percentage of minorities, elevation-slope integrated terrain and comprehensive geological condition. Besides, this paper uses AHP supported by entropy technique and fuzzy membership function model to calculate the suitability evaluation index and then divides the disaster areas into five types: highly suitable area (area accounted for 11.03%), relatively highly suitable area (15.29%), moderately suitable area (29%), less suitable area (30.08%) and unsuitable area (14.6%). According to the result of suitability evaluation, this paper puts forward several suggestions for the reconstruction as follows: the urban system and the building of new countryside should be guided by the suitability evaluation subareas; post-earthquake reconstruction avoids zones near Longmenshan fracture and high-mountain gorge areas as far as possible; the scale of population and settlement should not exceed the capacity of resources and environment; population should be resettled as close as possible by considering adequately the heterogenicity and homogeneity of regional nationality culture characteristics; densely resettle the people at plains and hilly areas; encourage the migrant workers settle in the working place with their families voluntarily; and urban system reconstruction such as industry layout and important projects of lifeline should be guided by the spatial layout suitability evaluation.     

渤海湾牡蛎礁平原中部兴坨剖面全新世地质环境变迁

渤海湾牡蛎礁平原中部兴坨剖面的有孔虫组合划分为5种沉积环境7个带(亚环境)，从下向上依次为晚更新世陆相(Ⅶ带)、早全新世海陆过渡相(Ⅵ带：沿海低地与潮间带)、中晚全新世海相(Ⅴ带：潮下带-浅海，Ⅳ带：低潮线附近)、晚全新世海陆过渡相(Ⅲ带：开放潮间带，Ⅱ带：渴湖)和河流泛滥相(Ⅰ带：古土壤及洪积层)。^14C确定了全新世底泥炭始于9486 cal BP，Ⅳ带始于约4696 cal BP。Ⅱ带所处的渴湖环境，从约4000 cal BP直至隋唐温暖期之前，历时约2700年。隋唐暖期古土壤发育向南东减弱至逐渐消失，说明在比兴坨更靠近渤海湾的地方，潟湖持续的时间更长。广泛存在的潟湖，是牡蛎礁平原晚全新世的重要地貌景观。     

低温氮、磁化综合处理钻头使用性能提高的X射线 和电子显微技术分析研究

在地质钻探和石油钻井中,钻头都是非常重要的钻进工具。其技术特性,特别是硬度和耐磨性与钻探的技术经济指标,即与机械钻速、钻头进尺和每米钻探成本直接相关。为了提高钻头的工作性能,俄罗斯南方国立技术大学提出了综合低温淬火、磁化回火处理钻头的方法。经过综合处理后,钻头体、复合片底座和钎焊层的硬度分别提高了30%、3%和22%。野外钻进试验结果表明,经过低温液态氮和磁化综合处理的与未经综合处理的钻头相比,每次试验钻头进尺都有提高,总体上钻头进尺提高了222%,取得了很好的钻进效果。并对取得的效果进行了X射线和显微技术分析。     

锡林郭勒盟近50年最高气温时空变化特征

利用内蒙古锡林郭勒盟15个气象站1961—2009年逐日最高气温资料,分析了锡林郭勒盟平均最高气温、高温日数的时空分布特征。结果表明:锡林郭勒盟平均最高气温在空间上呈西高东低、中部高南北低的分布,历史演变上呈先下降后升高的变化趋势;高温日数空间上呈西多东少分布,其中高值中心出现在苏尼特右旗、二连浩特市一带,低值中心出现在南部地区,最低点出现在1976年。