耿贝尔逻辑模型在极值风速和有效波高联合概率分布中的应用

首先介绍了耿贝尔逻辑模型，采用该模型对南海海域的涠州岛海洋站的风速和有效波高实测数据进行了分析，结果表明耿贝尔逻辑模型较好地描述了年极值风速和有效波高两随机变量的联合分布；采用得到的极值风浪联合概率分布推算了不同重现期的极值风速和波高，表明考虑风速和波高相关性对设计荷载的确定有显著影响。由于耿贝尔逻辑模型具有函数结构简单，参数估计方便，因此有望成为极值风速和波高联合分布的较理想概率模型。     

广西沿岸海平面变化的关联维数研究

采用相空间重构和关联维数方法，研究了广西沿岸月平均海平面变化的分形特征，结果表明，相空间重构的延迟时间τ为3△t，当关联维数趋于饱和时，石头埠，北海和龙尾的相空间维数为7，而涠洲岛为9，它们的关联维数平均值平均值分别为6.6507,6.5414,6.7059.     

某矿山天然放射性核素的调查

对某矿山工作场所和生活区分别进行了样品采集,并使用ORTEC公司生产的16000道HPGeγ能谱仪进行了测量。结果表明,该矿山工作场所天然放射性核素的比活度大多高于生活区,其中危害最大的为尾矿坝;某些生活区天然放射性核素的比活度比对照点和国家均值要高,但多数都在国家均值范围内,最高值出现在3号生活区的农田土样中,其天然放射性核素的比活度分别为：α（226^Ra）——750．4Bq/kg、α（232^Th）——91．5Bq/kg、α（40^K）——1202Bq/kg。     

辽东南地区晚中生代地层序列与盆地演化规律

辽东南地区晚中生代地层发育不甚完全,具有两期盆地叠合演化的特征,即早中侏罗世和早白垩世两个演化阶段,经历了2次伸展裂陷和2次挤压反转。在详细研究辽东南地区各盆地岩石地层序列、生物化石组合特征、年代地层格架以及区域地层对比的基础上,讨论了盆地的演化阶段和演化规律,指出是古太平洋板块向东亚大陆边缘不同方向的俯冲与走滑,以及来自北方西伯利亚板块的持续碰撞挤压的联合构造应力场制约了中国东北地区晚中生代盆地的裂陷过程和构造反转的演化,进而为揭示华北克拉通晚中生代岩石圈演化的动力学机制提供参考依据。     

Spatial distribution features and environment effect of heavy metal in intertidal surface sediments of Guanhe estuary, Northern Jiangsu Province

In northern Jiangsu coastal zone area, Guanhe River is the biggest river and has the best navigation conditions among rivers which flow into the Yellow Sea. The grain sizes show gradual increase from the high intertidal zone to lower intertidal zone. The heavy metal values have slight changes along both sides of the river mouth, but show an evident change perpendicular to the tidal flat. In the latter case, they show a good correlation with grain size fluctuation, that is, the heavy metal values gradually decline when the grain size increases from the high intertidal zone to the lower intra-tidal zone. Analyses of the heavy metal elements show that on the Guanhe estuary surface sediment, the content of the elements Hg, As and Cu is above background values; Pb and Zn contents are rather close to the background values; and Cd content is less than the background values. The element Hg comes out to be harmful in a medium level to ecological environment, while the elements of Cr, As, Cu, Pb, Zn and Cd fall in a safe range of MPL. On the whole, Guanhe estuary tidal flat is not very harmful to the ecology in terms of the heavy metals. __________ Translated from Marine Geology & Quaternary Geology, 2007, 27(5): 23–32 [译自: 海洋地质与第四纪地质]     

黑龙江省鸡西盆地南、北两带城子河组精细对比

鸡西盆地被平麻断裂分割成南、北两个条带,多数研究者将南带1煤之下的海相层叠伏于北带海相层或底砾岩之下,称为“城子河组下段”或“石河北组”。利用事件地层学的原理,分析盆地内城子河组早期盆地裂陷、海侵、火山喷发、聚煤等重大事件在地层精细对比方面的意义,甄别出了盆地中重大事件的地层记录．以等时层为基础建立对比框架。通过大量钻井资料追溯对比,认为盆地中坳陷部位的渴湖海湾沉积是南北两带的沉积过渡类型,根据微体古生物研究,南北两带海相层中的沟鞭藻类化石面貌基本一致,南北带的海相层应是同一层位,初步实现了盆地内南、北两个条带城子河组的精细对比,为恢复盆地古地理环境奠定了可靠的基础。     

青龙煤矿采探对比及构造分析

通过对青龙井田两次勘查进行采探对比分析,认为存在工程量不足、构造和煤层控制程度低、高级资源量比例低、地质规律研究不足等问题。青龙井田构造以断层为主、褶曲为辅,小断层、小型紧闭褶曲极为发育,断层具有落差大、密度大、延展长度大、相互切割、下盘牵引破坏明显等特点,断层总体以NE向为主,可分为NE向正、逆断层组,NW向正、逆断层组4组。井田F4、F22断层附近及F4断层以南、F22断层东南为构造复杂区,升田深部为构造较复杂区,综合评价井田构造复杂程度为较复杂一复杂类型。目前矿井生产被动局面是由于地质构造复杂、煤层稳定性差和前期勘查程度低造成,通过分析构造和煤层对采区和工作面设计、工作面回采等影响,提出了今后井田勘查、矿井生产和地质丁作建议,对贵州煤矿地质工作具有一定的借鉴作用。     

Estimation of covariance matrix from geochemical data with observations below detection limits

Multivariate statistical analyses have been extensively applied to geochemical measurements to analyze and aid interpretation of the data. Estimation of the covariance matrix of multivariate observations is the first task in multivariate analysis. However, geochemical data for the rare elements, especially Ag, Au, and platinum-group elements, usually contain observations the below detection limits. In particular, Instrumental Neutron Activation Analysis (INAA) for the rare elements produces multilevel and possibly extremely high detection limits depending on the sample weight. Traditionally, in applying multivariate analysis to such incomplete data, the observations below detection limits are first substituted, for example, each observation below the detection limit is replaced by a certain percentage of that limit, and then the standard statistical computer packages or techniques are used to obtain the analysis of the data. If a number of samples with observations below detection limits is small, or the detection limits are relatively near zero, the results may be reasonable and most geological interpretations or conclusions are probably valid. In this paper, a new method is proposed to estimate the covariance matrix from a dataset containing observations below multilevel detection limits by using the marginal maximum likelihood estimation (MMLE) method. For each pair of variables, sayY andZ whose observations containing below detection limits, the proposed method consists of three steps: (i) for each variable separately obtaining the marginal MLE for the means and the variances, , , , and forY andZ: (ii) defining new variables by and and lettingA=C+D andB=C–D, and obtaining MLE for variances, and forA andB; (iii) estimating the correlation coefficient _YZ by and the covariance _YZ by . The procedure is illustrated by using a precious metal geochemical data set from the Fox River Sill, Manitoba, Canada.     

Cross-formational hydrocarbon fluid flows in the Tertiary deltaic system of the Beaufort–Mackenzie Basin

Molecular and isotopic compositions of crude oils in the Beaufort–Mackenzie Basin confirm three genetic end-member oil groups and suggest extensive cross-formational hydrocarbon fluid flows in the Tertiary deltaic system. Inter- and intra-fractional variations in the geochemistry of the Tertiary-reservoired oils indicate that the oil source/maturity signatures were substantially masked by biomarkers that were picked up along migration pathways. Thus, many of the previously recognized “immature non-marine oils” are in fact thermally mature, probably derived from unpenetrated deeper marine source rocks. Although the effective source rock volumes have not been evaluated and their exact stratigraphic levels remain unknown, the relative timing of oil generation versus trap formation, rather than poor source quality, may be the cause of under-filled traps in the offshore area.