Major element composition of the pelites of the Scottish Dalradian

Major element composition of the available analysed pelitic rocks of the Dalradian of Scotland is examined in relation to geographical position, mineralogy, metamorphic grade and stratigraphy. Some of the large variations found are due to geographical position, possibly reflecting different provenance. A major compositional difference exists between the two lower Barrovian metamorphic zones and the four higher zones. This is considered to be a reflection of the original sedimentary composition and large scale metasomatism is not considered likely.     

东北大西洋北海渔场鱼类群落结构年际变化研究

根据2001-2015年东北大西洋北海渔场进行的国际底拖网调查渔获数据,采用生物多样性指数和多元统计分析研究该海域群落结构的年际变化,并利用格局转变贯序t检验的方法研究鱼类种群的转变规律,结合环境因素与捕捞因素分析群落结构变化的原因。结果显示:2001-2015年北海渔场共出现280种渔业资源,其中鱼类有222种,资源丰度波动较大;物种多样性整体呈上升趋势。聚类分析和非度量多维标度排序分析表明,研究期间大致分为2001-2003年、2004-2011年和2012-2015年3个阶段。大西洋鲱分别在2004年和2014年种群结构发生格局转变,格局转变指数（RSI）分别为-0.45和0.41;黑线鳕在2003年和2012年格局发生转变,RSI值分别为-0.58和-0.66;黍鲱在2014年格局发生转变,RSI值为2。通过对环境因素与捕捞因素的分析发现,北海渔场群落格局第一次发生转变主要受捕捞因素影响,第二次发生转变主要受环境因素影响。     

THE LAST GLACIATION OF SHETLAND, NORTH ATLANTIC

Evidence relating to the extent, dynamics, and relative chronology of the last glaciation of the Shetland Islands, North Atlantic, is presented here, in an attempt to better illuminate some of the controversies that still surround the glacial history of the archipelago. We appraise previous interpretations and compare these earlier results with new evidence gleaned from the interpretation of a high resolution digital terrain model and from field reconnaissance. By employing a landsystems approach, we identify and describe three quite different assemblages of landscape features across the main islands of Mainland, Yell and Unst. Using the spatial interrelationship of these landsystems, an assessment of their constituent elements, and comparisons with similar features in other glaciated environments, we propose a simple model for the last glaciation of Shetland. During an early glacial phase, a coalescent British and Scandinavian ice sheet flowed approximately east to west across Shetland. The terrestrial land‐forms created by this ice sheet in the north of Shetland suggest that it had corridors of relatively fast‐flowing ice that were partially directed by bed topography, and that subsequent deglaciation was interrupted by at least one major stillstand. Evidence in the south of Shetland indicates the growth of a local ice cap of restricted extent that fed numerous radial outlet glaciers during, or after, ice‐sheet deglaciation. Whilst the absolute age of these three landsystems remains uncertain, these new geo‐morphological and palaeoglaciological insights reconcile many of the ideas of earlier workers, and allow wider speculation regarding the dynamics of the former British ice sheet.     

大息场组——黔东北思南奥陶系—志留系之交的一个新地层单元

黔东北思南鹦鹉溪大息场剖面出露奥陶系-志留系界线处的地层序列,该序列与周缘地区相比较,具有其岩相和生物相的特殊性,以此为据建立新地层单元--大息场组。大息场组实测厚度129.7 m,主体岩性由灰色和灰黄色薄层-中层细砂岩和粉砂岩组成,下部暗色粉砂岩中产出3层笔石,指示该组时限为凯迪期晚期到鲁丹期末期。大息场组的碎屑岩层之间不存在暴露海平面之上的标志,表明这里地处局限的凹陷带,此时黔中古陆以北发生的海退未波及至此。     

1990年以来东北地区工业结构演变特征及驱动因素

工业结构优化升级是振兴东北老工业基地的一项核心任务。基于对区域工业行业结构、所有制结构、企业规模结构动态变化的定量分析,总结了1990年以来东北地区工业结构演变特征与存在的问题,分析了区域工业结构演变的主要驱动因素,并探讨了区域工业结构优化升级的发展方向。研究表明：1990年以来东北地区工业结构调整在解决体制性矛盾、发挥存量优势方面成效明显,在政府支持、外资驱动、市场需求拉动以及资源环境压力等因素的影响下,东北地区工业结构高加工度化发展趋势初步显现,重工业比重持续上升的态势得到遏制,工业所有制结构调整阶段性效果显著,所有制结构单一的现象得到改善,企业规模分化现象近年来表现出下降趋势,大型工业企业主导工业发展态势的局面正在逐步改变。但偏重的工业结构未发生实质性改变,优势工业行业构成变动不明显,多数新兴工业行业规模较小,高技术产业发展滞缓,推动区域工业结构优化升级的内生性动力不足,工业结构优化升级与拉动就业之间的矛盾开始凸显。     

东北地区构造分区与深断裂研究——基于重力场小波多尺度分解

基于东北地区的布格重力异常资料,通过小波多尺度分解,将重力异常分解为四阶.提取主要反映深断裂的重力异常2、3阶小波细节,利用不同方向的水平梯度,计算并强化深断裂的线性特征,解译出12条深断裂,同时,结合功率谱法、东北地区地震分布、震源机制解和地质信息推断断裂的下切深度和性质,结果表明:12条深断裂分别对应拼贴地块的缝合带和对东北地区盆地群的分布与演化有着明显控制作用的岩石圈断裂两类;深断裂体系主要方向为北东、北北东向且大多为走滑断层;提取主要反映深层块体异常的3、4阶小波细节并结合深断裂体系将研究区划分为五个重力场一级分区,并首次将额尔古纳块体和兴安块体分开.五个大区分别为额尔古纳块体、兴安块体、松嫩块体、佳木斯块体和华北板块;其中兴安块体又分为二连盆地、大兴安岭两个二级分区;松嫩块体又分为小兴安岭、松辽盆地、张广才岭三个二级分区;佳木斯块体又分为那丹哈达地体、三江盆地、桦南—穆棱三个二级分区,华北板块又分为辽东半岛、华北板块、北部断裂带三个二级分区,结果表明了研究区的基本构造格局.     

桂东北姑婆山岩体矿物学和年代学特征及其成岩成矿意义

为揭示桂东北姑婆山一带花岗岩的成岩成矿特征,本文对姑婆山岩体进行了黑云母矿物化学成分分析和锆石U-Pb年代学研究。花岗岩中黑云母化学成分分析结果表明：黑云母具有富铁镁、贫钙钠的特征,w（TFeO）为26.78%~31.06%、w（MgO）为2.98%~6.60%,且w（TFeO）与w（MgO）呈明显的负相关性,说明其结晶过程中主要发生了Fe²⁺←→Mg²⁺的置换反应;黑云母的含铁指数为0.68~0.84,属于高铁黑云母,氧逸度为-17.0~-15.5,结晶温度为680~705℃,平均为695℃;黑云母的全铝压力计显示黑云母结晶的压力为69~179 MPa,平均为115 MPa,对应的侵位深度相当于2 621~6 755 m,平均深度为4 331 m。年代学分析结果显示,采自姑婆山岩体的两个代表性花岗岩样品形成年龄分别为（162±3）和（163±2）Ma,为燕山早期,与华南中生代大规模岩浆-成矿作用时代一致。综合上述分析,姑婆山岩体形成于较高温度、低氧逸度、较浅的环境,显示出良好的锡成矿性,具有良好的找矿前景。     

基于GIS的粮食生产安全预警研究——以东北三省为例

本文借鉴国内外有关预警理论和实践的最新成果,对粮食生产安全预警的基本方法进行了探讨,建立了基于全国的区域粮食生产安全预警模型,并以东北三省为例,借助GIS进行实证研究。研究结果表明,吉林和辽宁两省2000年粮食生产安全程度低于2003年,而黑龙江省则相反,2000年的粮食生产安全程度则高于2003年,这与东北地区粮食生产实际状况相符,表明该模型可以较客观地反映区域粮食生产状况。文章最后根据模型对东北地区2010年的粮食生产安全进行了预测。     

基于Sato模型的内蒙古东北部地区尾波Q值

基于Sato模型,采用2016年3月至2018年6月内蒙古东北部及临近地区发生的526次地震事件,挑选M_L ≥ 2.0、记录清晰且信噪比较高的102次地震事件,拟合得到内蒙古东北部地区尾波Q值,得到Q_C（f）=（64.74 ±29.09）f^{（0.8925 ±0.0765）};Q值与依赖指数η成反比,且该区北部Q值偏高,南部Q值偏低,可能与地质构造及地震活动性有关。     

The application of GPR and ERI in combination with exposure logging and retrodeformation analysis to characterize sinkholes and reconstruct their impact on fluvial sedimentation

This work illustrates the practicality of investigating sinkholes integrating data gathered by ground penetrating radar (GPR), electrical resistivity imaging (ERI) and trenching or direct logging of the subsidence‐affected sediments in combination with retrodeformation analysis. This mutidisciplinary approach has been tested in a large paleosinkhole developed during the deposition of a Quaternary terrace on salt‐bearing evaporites. The subsidence structure, exposed in an artificial excavation, is located next to Puilatos, a village that was abandoned in the 1970s due to severe subsidence damage. Detailed logging of the exposure revealed that the subsidence structure corresponds to an asymmetric sagging and collapse paleosinkhole with no clear evidence of recent activity. The sedimentological and structural relationships together with the retrodeformation analysis indicate that synsedimentary subsidence controlled channel location, the development of a palustrine environment and local changes in the channel pattern. GPR profiles were acquired using an array of systems with different antenna frequencies, including some recently developed shielded antennas with improved vertical resolution and penetration depth. Although radargrams imaged the faulted sagging structure and provided valuable data on fault throw, they did not satisfactorily image the complex architecture of the fluvial deposit. ERI showed lower resolution but higher penetration depth when compared to GPR, roughly capturing the subsidence structure and yielding information on the thickness of the high‐resistivity alluvium and the nature of the underlying low‐resistivity karstic residue developed on top of the halite‐bearing evaporitic bedrock. Data comparison allows the assessment of the advantages and limitations of these complementary techniques, highly useful for site‐specific sinkhole risk management. Copyright © 2016 John Wiley & Sons, Ltd.