西准噶尔志留纪-泥盆纪弧盆格局的确定及其区域构造演化意义

新疆西准噶尔克拉玛依-额敏一带广泛出露古生代的物质建造,记录着古亚洲洋演化的重要信息.古生代期间特别是晚古生代期间经历了复杂的洋陆转换过程,残留了系列近东西向及北东向蛇绿构造混杂岩系以及古大陆边缘的增生体系,造就了研究区复杂的岩石地层系统.目前对西准噶尔志留系、泥盆系构造古地理属性及志留纪-泥盆纪构造格局的刻画并不够精细.通过详细地野外地质调查及室内数据综合分析,结合前人的研究资料,对西准噶尔克拉玛依-额敏一带志留系及泥盆系代表性的岩石地层的构造古地理属性进行了界定,并在此基础上,对研究区志留纪-泥盆纪的弧盆格局进行探讨.综合分析认为志留纪西准噶尔克拉玛依-额敏一带古亚洲洋开始强烈的俯冲消减,泥盆纪古亚洲洋进入全面俯冲拼贴的演化阶段,形成多块体拼贴增生的多岛弧盆格局.泥盆纪后古亚洲洋在研究区开始进入残余洋盆的演化阶段.      

西准噶尔古生代地层区划及古地理演化

根据大地构造环境与沉积组合(建造)类型,地层序列与地层接触关系,古地理格局与古环境条件,古生物类型与生物古地理区系,地层类型与地层的变形、变质和变位特征,地层区划的边界类型与识别标志,地层区划可以区分为综合和断代地层区划2类,都可以分为4级:地层大区(stratomegaregion)、地层区(stratoregion)、地层分区(stratosubregion)和地层小区(stratomicroregion).基于近年来取得的大量新资料、新认识和上述地层区划6方面的判据,西准噶尔地区古生代地层区划自北向南划分为萨吾尔山地层小区、沙尔布尔提山地层小区、玛依力山地层小区和克拉玛依地层小区.在构造古地理上,西准噶尔地区古生代表现为多岛洋和软碰撞的特点,志留纪后期至早石炭世是多岛洋和软碰撞的鼎盛时期,也是西准噶尔地区古生代地层区划的重要形成时期;晚石炭世至二叠纪,西准噶尔地区主体脱离海洋环境,进入陆内造山阶段,西准噶尔地区古生代地层的分区性逐渐消失.在生物古地理上,早古生代西准噶尔地区属于介于太平洋生物大区与大西洋生物大区之间的混生生物大区,不同于东北部西伯利亚板块南部由Tuvaella(图瓦贝)动物群所代表的生物区系;从志留纪至泥盆纪,西准噶尔地区的生物组合面貌明显属于热带-亚热带的古特提斯生物大区;晚石炭世-二叠纪西准噶尔地区陆相地层中的植物群面貌显示出明显的北温带安加拉植物群的特点.在沉积古地理上,西准噶尔地区古生代的作用相包括正常沉积与事件沉积,特别是反映活动构造环境的内力事件沉积特别发育,如火山爆发相、火山溢流相和震积岩相;环境相包括古陆、河流相、滨-浅海相和半深海-深海相.      

A Rapid Acid Digestion Technique for the Simultaneous Determination of Bromine and Iodine in Fifty‐Three Chinese Soils and Sediments by ICP‐MS

Bromine and iodine are important tracers for geochemical and environmental studies. In this study, a rapid acid digestion (HNO₃ + HF) with ammonia dilution for the simultaneous determination of bromine and iodine in soils and sediments using ICP‐MS was developed. The recoveries of Br and I were controlled by the synergic effect of temperature and time. It took only 15 min at 140 °C for the complete recovery of Br and I in sediment (GSD‐2) and soil (GSS‐24) reference materials, which is a process that needs 2–6 h at 90 °C. A serious loss of Br and I was found at a higher digestion temperature of 190 °C. A 5% v/v NH₄OH dilution effectively eliminated the memory effects and stabilised the signals of Br and I. Moreover, ammonia dilution also avoided the corrosiveness of HF on the sample introduction system and torch of ICP‐MS. Tellurium is a more suitable internal standard element than In in the ammonia medium. To avoid the adsorption of residues of dissolution on Te, addition of Te should be carried out after centrifuging the solution. The developed method was successfully applied to determine Br and I in fifty‐three Chinese soil and sediment reference materials. This simple method shows great potential for the rapid determination of Br and I in large batches of geological and environmental samples commonly analysed for mineral exploration and environmental geochemistry studies.     

Factors that influence fluid flow in a single fracture

To investigate the influence of compression, Poisson effect and turbulence on the fluid flow process and the inversion for fracture surface geometries, we simulate two sets of fractures: one with a defined fracture height standard deviation σ constant and a varying autocorrelation length λ and another with a fixed λ and a changing σ. Under compression, the normal stress closes fractures with a large aperture and thus reduces the effective permeability. However, the Poisson effect, which is induced by the compression, has little influence on the fluid flow properties and does not affect the inversion for fracture height standard deviation or the autocorrelation length. When introducing turbulence, we observe a significant difference between the performance of the Navier–Stokes equation and the local cubic law; compared with the Navier–Stokes equation, the local cubic law overestimates the peak value of the breakthrough time curve and effective permeability, thereby underestimating the mean fracture aperture.     

热带气旋路径强度预报——SAPC法

SAPC——逐段相似气候持续性热带气旋路径、强度预报方法，既考虑了热带气旋的气候持续性规律，又考虑了与现时热带气旋状态特别相似的历史热带气旋路径、强度变化规律，用不同的相似条件和权重，把气候路径、相似路径和持续性路径作了有机的统一。该方法克服了预报路径的大曲率变化，考虑了随时间、地点变化的热带气旋的气候规律，根据热带气旋的现时状态，即可随时制作路径、强度预报。历史资料和实际应用表明该方法有实用价值。     

裂缝发育区平面分布的分形评价

裂缝是一种具有强烈非均质特征的油气储集 体,其在三维空间内的分布具有非 线性特征。运用相似维数统计法对裂缝发育带在二维平面内分布的分形特征进行研究,并用 该定量参数进行层间裂缝发育程度的定量对比。理论上证实,相似维数这一分形参数可以定 量表征裂缝发育带对二维空间的充填能力,实际统计结果表明,裂缝发育带的统计相似维数 高低与层间总体产能的对比关系是完全吻合的。     

Late Quaternary environmental changes in the Pearl River mouth region, China

This study presents findings concerning Late Quaternary environmental changes in the Pearl River mouth region, China based on the study of over 300 boreholes. Out of these, 35 boreholes are selected for the reconstruction of transects across the deltaic plain and estuary. 39 radiocarbon dates obtained from these boreholes are used to help define the chronology of stratigraphic units present including two terrestrial units (T1 and T2) and two marine units (M1 and M2). Diatom assemblages are studied in 6 boreholes revealing similarities and differences between the two marine units. Before the area was inundated by the last interglacial sea (MIS 5), an older terrestrial unit of sand and gravel (T2) was laid down in a number of palaeo-valleys. During the last interglacial period, an older marine unit of silt and clay (M2) was laid down which was subsequently subaerially exposed when sea-level regressed during the last glacial period (MIS 4-2) causing the uppermost section to be weathered. During the same period, a younger terrestrial unit of sand and gravel (T1) was deposited along palaeo-river channels. Around the early Holocene before 8.2 cal. ka BP, the postglacial rise in sea level initiated a new phase of sedimentation in the outer part of the estuary, characterised by the high percentages of marine diatoms in the sediments. In the early Holocene, strong monsoon freshwater discharge resulted in sedimentation of a fine-sand layer in the inner part of the estuary. After 8.2 cal. ka BP, rapid rises in sea level caused widespread marine inundation and sedimentation. The diatom data suggest that the relative sea level associated with the M2 and M1 units were both at similar levels. Because the M2 unit is typically recorded at altitudes of 15 m and 20 m below the present sea level, this is likely to be a result of long-term subsidence. Although numerical dating of the pre-M1 units has not been made in the present study, the chronology of these units can be inferred from uranium-series ages and optically stimulated luminescence dating obtained from the adjacent coastal waters of Hong Kong. The T1 unit has yielded ages of about 30.0 cal. ka BP while the M2 unit has yielded ages about 130.0 cal. ka BP confirming their MIS 4-2 and MIS 5 ages respectively.     

国家气象计算网格的设计与建立

气象部门内高性能计算资源与支持能力具有地域分布不均匀的特点,地方部门与国家级单位相比,在资源丰富程度和开发应用水平上都存在较大差距。针对气象部门国家级、地方单位的资源整合、共享和管理的需求,该文提出了一个国家气象计算网格的设计方案。设计方案采用国家级、区域、省级三级节点布局,通过跨广域范围的气象宽带网互联,基于整合的资源平台设置了资源管理、应用服务和用户接口等功能层模块。利用UNICORE等关键技术,开发实现了气象计算网格软件模块。建成了一个全国分布的6个网格节点,提供网格中间件和定制业务运行两种资源共享服务方式。业务运行以来,为资源匮乏地区的气象用户共享分发预报服务产品,为当地的减灾防灾工作做出了贡献。     

气象服务需求的理论研究

气象服务需求是气象经济学中亟待深入研究的问题。从经济学的需求意义上,立足于气象服务实践,提出气象服务需求主体与需求客体,进而把需求主体划分为政府和企业,把需求客体划分为公共产品和服务商品。并在此基础上,重点剖析制约公共气象服务产品的需求因素和制约气象商品的需求因素