山东碳酸岩磷灰石的特征及其研究意义

鲁中隆起的北缘分布着100多个燕山期的碳酸岩体。本文详细研究了岩体中磷灰石的一些重要特征,包括晶体形态、物理性质、光学常数、晶胞参数、化学成分、包裹体及钕锶同位素组成等。并据所得资料对岩体的成因,成岩物质来源等问题进行探讨。     

Multifractal modeling and spatial point processes

The multifractal model can be applied to spatial point processes. It provides new, approximately power-law type, expressions for their second-order intensity and K (r) functions. The box-counting and cluster dimensions are different but mutually interrelated according to multifractal theory. This approach is used to describe the underlying spatial structure of gold mineral occurrences in the Iskut River area, northwestern British Columbia. The box-counting and cluster dimensions for the example are estimated to be 1.335±0.077 and 1.219±0.037, respectively. The relatively strong clustering of the gold deposits is reflected by the fact that both values are considerably less than the corresponding Euclidean dimension (=2).     

Cosmic-ray exposure histories of two Antarctic meteorites from Chinese collections and the Guangmingshan and Zhuanghe chondrites

In this paper, we report cosmic-ray exposure ages (3He, 21Ne, 38Ar) and gas retention ages (4He, 40Ar) of two Antarctic meteorites, and the Guangmingshan and Zhuanghe ordinary chondrites. The Antarctic meteorites (GRV98002 and GRV98004) were collected on …     

Influence of wave groups on SSC patterns over vortex ripples

Estimates of spatial and temporal variations in suspended sand concentrations (SSC) made with a multi-transducer Acoustic Backscatter Sensor (ABS) under a repeated wave group over a mobile rippled bed in the wave research flume at the National Hydraulics Laboratory in Ottawa, Canada, reveal an number of complex and intriguing patterns. Ensemble averages of 8 nearly identical wave groups provided much more robust estimates of SSC and allowed a detailed examination of the wave group effects. The largest SSC near the bed (< 0.10 m) occurs in phase with the largest waves in the group. Above approximately 0.10 m elevation, SSC lags behind the near bed SSC by as much as 2–3 waves; introducing significant curvature (on a semi-log plot) to the SSC profile. The log linear segments of the SSC profile grow and decay systematically on the scale of the wave group. The range in lengths of log-linear profile segments ( 0.03–0.355 m) suggest that the boundary layer thickness also fluctuates throughout the passage of the wave group. Furthermore, there are significant variations in the patterns of SSC, which occur under the largest and smallest waves in the group. Under the largest waves vertical bands of alternating high and low SSC produce an intra-wave modulation in the upper water column ( 0.075–0.30 m). The equivalent horizontal excursion of these bands scales to the ripple length. Under the smaller waves the intra-wave modulation of the SSC disappears and is replaced by temporally homogenous suspension that expands vertically through several individual wave cycles. The former pattern of homogenous suspension appears to be associated with growth of a boundary layer due to the persistent uni-directional horizontal flow during this part of the group together with the persistence of antecedent bed generated turbulence and vorticity which maintains the suspension. The latter pattern of bands of high and low SSC indicates a strong temporal and spatial constraint on the SSC (phase coupling) induced by the presence of the bedforms which may be enhanced by strong reversals in both flow and vorticity under the large waves in the group.     

现代冲积河流的河型空间转化模式探讨

论述了现代冲积河流系统中常见河型的自然分布及转化特征,归纳了河型从上游向下游发生空间转化的 5种主要模式。这些河型转化模式发生的相对频率是不同的,其中从辫状河流向曲流河流转化的发生频率最大。文中通过具体实例总结了这些转化模式分别发生时的主要影响因素。     

井间断层的计算机分析方法

井间断层分析的研究,是油气储层地质研究的一项重要基础性工作,对油气的运移和聚集其中重要的控制作用。它是利用测井资料,以地层分层为基础,采用计算机技术实现井间断层分析的一种井间断层自动分析方法。动态波形匹配算法是本次研究采用的主要算法,它能够很好地建立井间地层之间的对比关系,通过曲线拟合、特征提取、匹配代价计算等步骤,自动绘制井间地层对比的路径图解。本文在对各种构造的路径图分析的基础上,总结出正断层、逆断层、不整合、同沉积断层、犁式断层和地层尖灭等30种情况下的路径图模式,提出路径图模式及相关概念。在大港油田的实例分析中取得了很好的效果。     

In situ cosmogenic ~(10)Be dating of the Quaternary glaciations in the southern Shaluli Mountain on the Southeastern Tibetan Plateau

It is generally considered that four-times ice age happened during the Quaternary epoch on the Tibetan Plateau. However, the research on the chronology of the four-times ice age is far from enough. The Shaluli Mountain on the Southeastern Tibetan Plateau is an ideal place for plaeo-glacier study, because there are abundant Quaternary glacial remains there. This paper discusses the ages of the Quaternary glaciations, based on the exposure dating of roche moutonnée, moraines and gla- cial erosion surfaces using in situ cosmogenic isotopes 10Be. It is found that the exposure age of the roche moutonnée at Tuershan is 15 ka, corresponding to Stage 2 of the deep-sea oxygen isotope, suggesting that the roche moutonnée at Tuershan is formed in the last glacial maximum. The expo- sure age of glacial erosion surface at Laolinkou is 130―160 ka, corresponding to Stage 6 of the deep-sea oxygen isotope. The oldest end moraine at Kuzhaori may form at 421―766 kaBP, corre- sponding to Stages 12―18 of the deep-sea oxygen isotope. In accordance with the climate charac- teristic of stages 12,14,16 and 18 reflected by the deep-sea oxygen isotope, polar ice cores and loess sequence, the oldest end moraine at Kuzhaori may form at stage 12 or stage 16, the latter is more possible.     

Three-dimensional simulations of air flow and momentum transfer in partially harvested forests

In order to predict wind loading on trees (canopy height h) in partially harvested forests, it is necessary to characterize air flow and momentum transfer in progressively more complex patterns where groups of trees (or aggregates) are retained. In this study, we used large-eddy simulation to explore the effects of aggregate size, inter-aggregate spacing, and the ratio between the aggregate size and inter-aggregate spacing on air flow and momentum transfer. Forty-five grid points across an aggregate were needed to achieve an adequate level of turbulence. Using grid sizes of h/15 throughout was too viscous for the smaller aggregates. Vertical and horizontal flow deflection by the leading aggregates sheltered some of the downstream aggregates to varying degrees where turbulence increased for subsequent rows. The number of rows of protected aggregates decreased as aggregate dimensions and the space between aggregates increased. A theoretical treatment of time-dependent wind is presented for the lead aggregate and a simulation case is presented for the case of a gust of reduced wind passing through the aggregate pattern. The leading aggregate responded with decreasing moment for decreasing ambient wind speed as predicted by theory. However, downwind aggregates experienced substantial increases in bending moment. The overall results of the disruptive aspects of time dependence agrees with arguments regarding the role of irrotational (potential) flow to this problem. Our treatment of retention pattern design is only a first step and further research suggestions are presented.     

基于规则格网数据断面极值法的一种改进方法

在研究基于规则格网数据地形特征提取过程中,主要有断面极值法和流水模拟法.在断面极值法中,针对传统断面极值法生成的特征线存在零碎、并行交叉等缺点,我们改进了传统的局部断面极值法,在特征线连接过程中增加了“将特征点邻域内其它候选特征点设置为已被引用、根据特征线长度与范围阈值筛选特征线“等条件,以克服生成的特征线存在的零碎和并行交叉问题.     

女山幔源包体及其寄主岩中微量元素和过渡金属元素的研究

对女山碧玄岩、超镁铁岩包体和高压巨晶中微量元素及过渡金属元素进行探讨。研究表明,碧玄岩中ＬＲＥＥ较之ＨＲＥＥ更为富集,其分配型式属ＬＲＥＥ富集型;包体中ＬＲＥＥ较ＨＲＥＥ略显富集之势,分配型式属平坦型,这与地幔具有平缓的ＲＥＥ模式相符,其中略富ＬＲＥＥ与碧玄岩对应。碧玄岩、包体和高压巨晶中过渡金属元素具有不同的分配型式。但是不管在碧玄岩与包体之间,还是在巨晶与碧玄岩之间,某些过渡金属元素的含量都具有相关关系。可见,碧玄岩与包体具有成因联系,巨晶与碧玄岩也具有成因联系。