History of faulting in the Northern Hastings Block,southern New England Orogen

Brittle failure is common in the Devonian to Permian rocks in the Northern Hastings Block (NHB) and is manifested by faults of different orientation and kinematic histories, but the timing of fault movement is not well defined. In this study, faults in the NHB were analysed with the map pattern of cross-cutting faults used to estimate the relative time of movement and relationship to other faults. We defined five episodes of faulting or fault reactivation that affected the NHB. The Yarras Fault System on the southwestern side of the NHB and the Parrabel Fault and related faults on the eastern side of the NHB are the two major fault systems responsible for transporting and rotating the NHB in the late Carboniferous. Faults on the eastern, northeastern and northern part of Parrabel Dome started and stopped moving after emplacement of the Hastings Block and before the intrusion of the Werrikimbe Triassic granitoids. We suggested that the movement on the major bounding faults is related to the accommodation of the NHB to the folding and cleavage development in the adjoining Nambucca Block, and is associated with the earliest part of the Hunter–Bowen Orogeny. Limited dextral movement on the extensions of the Taylors Arm Fault System caused minor displacements in the northeastern part of the NHB during the Late Triassic. Some small faults cut the Triassic granitoids or Triassic Lorne Basin sediments indicating tectonic activity continued post-Triassic.     

冬季东亚高空副热带急流和温带急流协同变化与中国南方地区降水的关系

利用NCEP/NCAR再分析数据和中国台站降水资料研究冬季东亚高空副热带急流和温带急流协同变化特征及其与中国南方地区降水的关系,发现冬季东亚高原急流与温带急流同期反向协同变化特征最为显著。即高原急流增强,同时温带急流减弱(SW型)和高原急流减弱,同时温带急流增强(WS型)。当高原急流增强(减弱)而温带急流减弱(增强)时,中国南方地区降水显著增加(减少)。合成分析表明,不同急流协同变化型态下冷暖空气活动特征存在较大差异,高原急流与温带急流的反向协同变化可以真实反映与冬季中国南方地区降水相关联的冷暖空气活动特征,进而导致不同降水形态的产生。     

Climate change mitigation scenarios and policies and measures: the case of Kazakhstan

This article illustrates the main difficulties encountered in the preparation of GHG emission projections and climate change mitigation policies and measures (P&M) for Kazakhstan. Difficulties in representing the system with an economic model have been overcome by representing the energy system with a technical-economic growth model (MARKAL-TIMES) based on the stock of existing plants, transformation processes, and end-use devices. GHG emission scenarios depend mainly on the pace of transition in Kazakhstan from a planned economy to a market economy. Three scenarios are portrayed: an incomplete transition, a fast and successful one, and even more advanced participation in global climate change mitigation, including participation in some emission trading schemes. If the transition to a market economy is completed by 2020, P&M already adopted may reduce emissions of CO₂ from combustion by about 85 MtCO₂ by 2030 – 17% of the emissions in the baseline (WOM) scenario. One-third of these reductions are likely to be obtained from the demand sectors, and two-thirds from the supply sectors. If every tonne of CO₂ not emitted is valued up to US$10 in 2020 and $20 in 2030, additional P&M may further reduce emissions by 110 MtCO₂ by 2030.     

运动学涡度在藏南冈底斯岩浆带中段谢通门-曲水韧性剪切带中的应用

一般剪切带主要由纯剪切和简单剪切共同作用,不同的剪切带及不同的构造位置两者所占有的比例不同。利用运动学涡度(Wk)可以定量地分析两者间的比值大小。本文通过极莫尔圆法和有限应变轴率Rs/石英c轴组构法对冈底斯岩浆带中段谢通门-曲水滑覆型韧性剪切带的运动学涡度进行了计算,两种方法获得了较为一致的结果。通过极莫尔圆法,对剪切带中的9组糜棱岩样品进行了运动学涡度计算,获得了Wk=0.73~0.96,平均值Wk=0.83。运用有限应变轴率Rs/石英c轴组构法对4个样品进行了分析,得到Wk=0.85~0.93,均值为0.88,两种方法获得了较为一致的应变结果。还根据极莫尔圆图解,计算了该韧性剪切带的减薄量S=0.09~0.35,平均减薄量为0.20。研究表明该韧性剪切带为典型的以简单剪切为主伴有部分纯剪切的一般剪切,该剪切带的形成可能与拉萨地体在中新世时从挤压到侧向伸展的转换有关。该剪切带变形特征和运动学涡度的确定深化了对藏南冈底斯地区的构造演化过程的理解,并对青藏高原中南部的地质研究具有推进作用。     

青藏高原地区云水时空变化特征及其与降水的联系

利用1984-2009年ISCCP的云量、云光学厚度(COT)、云水路径(CWP)资料,分析了青藏高原云水的分布特征、变化趋势,及其与夏秋季降水、冬春季降雪的联系.结果表明:青藏高原地区大气中的云水有着显著的季节变化与水平分布差异;青藏高原春夏季总云量、高云云量高于秋冬季,CWP、COT与总云量的分布特征具有较好的一致性.高原云量高值区位于喀喇昆仑山与高原东南部;可可西里地区由于羌塘高压的下沉作用为云量低值区.青藏高原总云量在1984-2009年间呈现减少趋势;而CWP在高原总体以增加为主,但在各区域上的变化不一致,高原东部CWP增加而西部出现较弱的减小,这与来自孟加拉湾的水汽输送增加有关.青藏高原中东部地区夏秋季降水受云量减少影响较小而与CWP的增加相一致呈增长趋势;该地区冬春季降雪略有减少,与总云量的年际变化具有正相关.     

点苍山-哀牢山杂岩带中北段嘎洒地区变沉积岩的成因矿物学与变质演化特征

点苍山-哀牢山变质杂岩带中北段嘎洒地区出露了多种典型的变沉积岩,其中夕线石榴黑云二长片麻岩和二云母片岩保存多期/多阶段矿物相转变特征,本文通过岩相学和矿物化学的综合分析,并结合传统矿物对温压计的估算结果,限定上述典型变沉积岩峰期角闪-麻粒岩相(M1)阶段、近等温减压-高温剪切变形阶段(M2)和晚期退变质(M3)阶段的矿物组合及变质温压条件。峰期角闪-麻粒岩相(M1)阶段的矿物组合为:石榴石(Grt)+板柱状夕线石(Sil1)+黑云母(Bt1)+钾长石(Kfs)+斜长石(Pl)+石英(Qtz)+钛铁矿(Ilm),变质温度压力条件为t=690~750℃,p=690~810 MPa;近等温减压-高温剪切变形阶段(M2)阶段,稳定矿物组合为:Grt+Sil2+Bt2+Kfs+Pl+Qtz+Ilm,黑云母在强烈走滑剪切作用下发生脱水熔融反应:2 Bt→Sil+6(Mg,Fe)O+K_2O+5 Qtz+2 H_2O,石榴石、黑云母和夕线石等受到剪切变形影响而发生强烈定向,形成的温度压力条件为t=650~720℃,p=450~630 MPa;晚期退变质阶段(M_3)的稳定矿物组合为:Qtz+Bt+Ms+Pl,退变的温度压力条件为t=580~640℃,p=400~500MPa。其变质演化p-T轨迹样式具有近等温减压的顺时针型式,表明点苍山-哀牢山变质杂岩带曾经历了一次明显的俯冲-碰撞造山事件,峰期变质可达到角闪-麻粒岩相;在碰撞后的构造折返过程中,上述变质岩石发生强烈的高温剪切变形作用,并伴随着黑云母等含水矿物的脱水熔融。     

冰层取心回转钻进模拟实验台的设计与测试

极地钻探实践表明,冰盖底部冰岩交界附近地质情况异常复杂,不但可能存在暖冰、基底融水,甚至还存在厚度不等的冰岩夹层,取心钻探异常困难,而优选钻头类型、确定合理的钻进参数是保证其安全、快速钻进的重要因素。本文设计了一套能够模拟冰层回转钻进的实验台,其技术参数为：钻压、转速分别可在0～10 kN、0～300 r/min范围内调节,最大扭矩约100 N·m。该实验台能够测量钻头切削具温度、钻孔深度及钻进速度等参数,为深入研究钻头类型及结构参数、钻进参数对扭矩、钻速和切削温度的影响规律提供了手段。采用PDC复合片钻头进行了冰钻实验,结果表明,实验台能够准确调节钻压和转速,可满足实验要求。     

Implications of structural inheritance in oblique rift zones for basin compartmentalization: Nkhata Basin,Malawi Rift (EARS)

The Cenozoic East African Rift System (EARS) is an exceptional example of active continental extension, providing opportunities for furthering our understanding of hydrocarbon plays within rifts. It is divided into structurally distinct western and eastern branches. The western branch comprises deep rift basins separated by transfer zones, commonly localised onto pre-existing structures, offering good regional scale hydrocarbon traps. At a basin-scale, local discrete inherited structures might also play an important role on fault localisation and hydrocarbon distribution. Here, we consider the evolution of the Central basin of the Malawi Rift, in particular the influence of pre-existing structural fabrics.Integrating basin-scale multichannel 2D, and high resolution seismic datasets we constrain the border, Mlowe-Nkhata, fault system (MNF) to the west of the basin and smaller Mbamba fault (MF) to the east and document their evolution. Intra basin structures define a series of horsts, which initiated as convergent transfers, along the basin axis. The horsts are offset along a NE–SW striking transfer fault parallel to and along strike of the onshore Karoo (Permo-Triassic) Ruhuhu graben. Discrete pre-existing structures probably determined its location and, oriented obliquely to the extension orientation it accommodated predominantly strike-slip deformation, with more slowly accrued dip-slip.To the north of this transfer fault, the overall basin architecture is asymmetric, thickening to the west throughout; while to the south, an initially symmetric graben architecture became increasingly asymmetric in sediment distribution as strain localised onto the western MNF. The presence of the axial horst increasingly focussed sediment supply to the west. As the transfer fault increased its displacement, so this axial supply was interrupted, effectively starving the south-east while ponding sediments between the western horst margin and the transfer fault. This asymmetric bathymetry and partitioned sedimentation continues to the present-day, overprinting the early basin symmetry and configuration. Sediments deposited earlier become increasingly dissected and fault juxtapositions changed at a small (10–100 m) scale. The observed influence of basin-scale transfer faults on sediment dispersal and fault compartmentalization due to pre-existing structures oblique to the extension orientation is relevant to analogous exploration settings.     

基于HJ-1A/1B的2014年黄海海域浒苔灾害时空分布

自2007年以来, 黄海海域每年的5月初～8月中下旬浒苔(Ulva prolifera)会周期性地暴发与消亡,导致海洋生态环境被破坏以及经济损失。利用2014 年的HJ-1A/1B遥感影像, 利用神经网络监督分类及RULE规则影像重分类动态阈值法, 对2014年的浒苔的漂移路径、各时期影响的海域面积、分布面积以及暴发高峰期的最大面积进行了动态监测。结果表明, 2014年浒苔持续时间为101 d, 5月中旬开始在江苏省盐城市近海出现零星斑点, 分布面积为2.299 km², 影响面积为1 744.799 km²; 6月初到6月中旬浒苔广泛分布于黄海海域, 分布面积扩大至1 367.145 km², 达到当年的峰值; 从6月下旬开始, 浒苔进入衰退期, 浒苔分布面积、相对聚集密度均急剧缩小, 但影响面积的峰值出现在该时期; 8月初消亡于青岛附近海岸, 8月20日遥感影像已难以监测到浒苔的存在。2014年黄海海域浒苔经过了“出现—发展—暴发—衰退—消亡”5个发展阶段。     

POM模式在日本南部黑潮路径变异研究中的应用

日本南部黑潮路径变异对北太平洋地区的气候和环境具有显著的影响,对黑潮路径变异的研究具有重要的意义。本文利用POM(Princeton Ocean Model)数值模式模拟了日本南部黑潮的路径变异情况,分析了黑潮大弯曲路径形成的可能机制。研究结果表明,当黑潮处于非大弯曲路径时,相对位势涡度的平均值呈现递减趋势,说明日本南部低位势涡度水在不断积累,这样会使得四国再循环流的强度增强,迫使黑潮保持平直路径,同时,近岸黑潮垂直流速剪切增大,斜压不稳定性的作用也逐渐增大;当黑潮从非大弯曲路径向大弯曲路径过渡时,再循环流强度的减弱会导致黑潮的流速剪切减小。根据海表高度异常场以及海洋上层流场信息发现,近岸黑潮附近的气旋涡会随着再循环流区域反气旋涡的东侧向南运动,最终导致黑潮大弯曲的发生。分析涡流的能量,结果显示,黑潮大弯曲路径的形成与斜压不稳定性密切相关。