CCD photometry of five X-ray selected BL Lacertae objects

We present the results of the monitoring of a sample of 5 HBLs in the B, V and R bands during 2003–2008. All sources in our monitoring project show significant rapid optical variations, except 1ES 1959+650, however; for 1ES 1959+650, the gamma-ray variability on a timescale of ～7 hours has been observed by Holder et al. (Astrophys. J. 583:L9, 2003). Using these variability timescales, we estimate the black hole masses for each source with the Kerr black hole theory.     

Color dependence of clustering properties of Luminous Red Galaxies (LRGs)

From the approximately volume-limited Luminous Red Galaxy (LRG) sample of the Sloan Digital Sky Survey Data Release 6 (SDSS DR6), we construct three LRG samples with different g-r color, which have the nearly same number density, to investigate the color dependence of clustering properties of LRGs. It is found that the blue galaxies have a more filamentary distribution than red galaxies, and that the bluest LRGs preferentially inhabit the dense groups and clusters. But in three LRG samples with different u-g color, we do not observe the tendency for clustering properties of LRGs to significantly change with color. We preferentially conclude that the clustering properties of LRGs are not strongly correlated with colors.     

南海地球物理场特征及基底断裂体系研究

南海海域主体可划分为南海北缘、中西沙、南沙南海海盆四块，各块具有明显不同的重磁场特征。反演得到的莫霍面总体趋势由陆向洋抬升，反映陆壳、拉伸陆壳、过渡壳、洋壳的分布。东沙高磁异常含一定的高频成份，与新生代玄武岩及中生代岩浆岩有关，而其低频成份可能反映了发育的下地壳高速层，南海海域断裂极为发育，可分为北东向断裂组、东西向断裂组、北西向断裂组和南北向断裂组，南海北缘、南缘均以北东向张性断裂与北西向张剪性、剪性断裂为主要格架，形成了、南北分带、东西分块”构造格局。     

Forecasting monthly inflow with extreme seasonal variation using the hybrid SARIMA-ANN model

The optimal operation of dam reservoirs can be programmed and managed by predicting the inflow to these structures more accurately. To this end, there are various linear and nonlinear models. However, some hydrological problems like inflow with extreme seasonal variation are not purely linear or nonlinear. To improve the forecasting accuracy of this phenomenon, a linear Seasonal Auto Regressive Integrated Moving Average (SARIMA) model is combined with a nonlinear Artificial Neural Network (ANN) model. This new model is used to predict the monthly inflow to the Jamishan dam reservoir in West Iran. A comparison of the SARIMA and ANN models with the proposed hybrid model’s results is provided accordingly. More specifically, the models’ performance in forecasting base and flood flows is evaluated. The effect of changing the forecasting period length on the models’ accuracy is studied. The results of increasing the number of SARIMA model parameters up to five are investigated to achieve more accurate forecasting. The hybrid model predicts peak flood flows much better than the individual models, but SARIMA outperforms the other models in predicting base flow. The obtained results indicate that the hybrid model reduces the overall forecast error more than the ANN and SARIMA models. The coefficient of determination of the hybrid, ANN and SARIMA models were 0.72, 0.64 and 0.58, and the root mean squared error values were 1.02, 1.16 and 1.27 respectively, during the forecast period. Changing the forecasting length also indicated that these models can be used in the long term without increasing the forecast error.     

Geology and geochemistry of the Changba SEDEX Pb-Zn deposit,Qinling orogenic belt,China

The Changba Pb-Zn SEDEX deposit occurs in the Middle Devonian sequence of the Anjiaca Formation of the Western Qinling Hercynian Orogen in the Gansu Province, China. The Changba-II orebody is hosted in biotite quartz schist and is the largest of 143 stratiform orebodies that are hosted either in biotite quartz schist or marble. The Changba-II comprises two types of mineralization: a bedded facies and an underlying breccia lens. The bedded section exhibits three sulfide sub-facies zoned from bottom to top: 1) banded sphalerite intercalated with quartz albitite; 2) interbedded massive pyrite and sphalerite ore; and 3) banded sphalerite ore intercalated with banded baritite. Major metallic minerals are sphalerite, pyrite, galena, with minor arsenopyrite, pyrrhotite, boulangerite, and rare chalcopyrite. The bedded sulfides are underlain by a lens of brecciated and albitized biotite-quartz schists cemented by sulfides and tourmaline.Massive and bedded sulfide ³⁴S values range from 8.1 to 29.3, whereas barite ³⁴S values range from 20.8 to 31.5. Disseminated pyrite in footwall schists has ³⁴S values ranging from 8.1 to 10.6, and increase to values ranging from 11.1 to 14.7 in the hangingwall. The lower ³⁴S values for massive and bedded sulfides are interpreted to be derived from progressive bacterial sulfate reduction (BSR) of Devonian seawater in a sulfate-restricted sub-basin. The higher ³⁴S values for massive and bedded sulfides could be a product of quantitative BSR but this is incompatible with barite being more abundant above the bedded sulfides. Instead, it is more likely that thermochemical sulfate reduction of seawater sulfate or of evaporite was the source of heavy hydrothermal sulfur. Heavy hydrothermal sulfur was injected into a sulfate-restricted sub-basin where it mixed with low ³⁴S BSR sulfide to form the massive and bedded sulfides. The REE patterns of sulfide layers and associated quartz albitite and baritite are similar to those of the host biotite quartz schists, suggesting that the hydrothermal fluids leached REE from the underlying rocks. Pb isotope ratios in galena form an array between the Upper Crust and the Mantle reservoir curves, which indicates that the lead is derived from upper crustal rocks comprising mafic igneous units. The Sr⁸⁷/Sr⁸⁶ ratio of 0.7101 for carbonate within the sulfide layers also suggests that Sr is derived from the mixing of Sr leached from upper crustal rocks with Middle Devonian seawater Sr. A Rb-Sr isochron age of 389.4 ± 6.4 Ma for sulfide layers and the interbedded hydrothermal sediments is consistent with the age of host Mid-Devonian strata. Ar³⁹/Ar⁴⁰ plateau age at 352.8 ± 3.5 Ma and Ar³⁹-Ar⁴⁰ isochron age of 346.6 ± 6.4 Ma for albite in the quartz albitite intercalated with sulfide layers indicate either albite formation after the sulfides or thermal resetting of the Rb-Sr system at about 350 Ma, the age of collision between the North China and Yangtze cratons.Editorial handling: E. Frimmel     

萨拉乌苏河流域萨拉乌苏组砂丘砂沉积特征

The Salawusu Formation of Milanggouwan section in Salawusu River Valley includes 7 layers of paleo-mobile dune sands, and 4 layers of paleo-fixed and semi-fixed dune sands. Their structures have been observed and their grain size, surface textural features and several main chemical elements have been analyzed. The results showed that： 1） Some of the aeolian structural characteristics of these dune sands are similar to that of the recent dune sands. 2） They are also similar to the recent dune sands in grain size components, and parameters of Mz,σ, Sk and Kg, as well as in several main chemical components. 3） The scattergrams of Mz-σ and SiO2-Al2O3＋TOFE and the probability curves of grain size showed that these paleo-dune sands are different from paleosols and fluvio-lacustrine facies, but are consistency with recent dune sands. 4） Quartz sands have well roundness and surface textural features such as dish-shaped pits, crescent-shaped pits, pockmarked pits, upturned cleavage plates, siliceous precipitates and siliceous crevasses, indicating that they had been carried for a long time by the wind. As the 11 layers of paleo-dune sands possess the aeolian characteristics in structure, grain size, surface textural features and chemical elements, the origin of their formation should be attributed to eolation.     

地下介质横向变化的地震多尺度边缘检测技术

本文提出的地震多尺度边缘检测技术以坎尼最佳边缘检测准则和小波变换的多分辨分析为理论基础,能在地震记录上较方便而可靠地识别地下介质的横向变化。这些横向变化包括不能用肉眼在地震同相轴上直接发现而又实际存在的隐蔽特征。对地层尖灭,透镜体、岩性变化和孔洞、裂缝发育带均可进行识别。模型计算和实际地震资料的处理结果显示该方法具有实际应用价值     

Uncertainties of geochemical modeling during CO<Subscript>2</Subscript> sequestration applying batch equilibrium calculations

One of the uncertainties in the field of carbon dioxide capture and storage (CCS) is caused by the parameterization of geochemical models. The application of geochemical models contributes significantly to calculate the fate of the CO₂ after its injection. The choice of the thermodynamic database used, the selection of the secondary mineral assemblage as well as the option to calculate pressure dependent equilibrium constants influence the CO₂ trapping potential and trapping mechanism. Scenario analyses were conducted applying a geochemical batch equilibrium model for a virtual CO₂ injection into a saline Keuper aquifer. The amount of CO₂ which could be trapped in the formation water and in the form of carbonates was calculated using the model code PHREEQC. Thereby, four thermodynamic datasets were used to calculate the thermodynamic equilibria. Furthermore, the equilibrium constants were re-calculated with the code SUPCRT92, which also applied a pressure correction to the equilibrium constants. Varying the thermodynamic database caused a range of 61% in the amount of trapped CO₂ calculated. Simultaneously, the assemblage of secondary minerals was varied, and the potential secondary minerals dawsonite and K-mica were included in several scenarios. The selection of the secondary mineral assemblage caused a range of 74% in the calculated amount of trapped CO₂. Correcting the equilibrium constants with respect to a pressure of 125 bars had an influence of 11% on the amount of trapped CO₂. This illustrates the need for incorporating sensitivity analyses into reaction pathway modeling.     

滇西北地区富碱岩体(脉)地质学及岩石化学特征

喜山期富碱岩体广布于滇西北地区 ,通过对其地质学和岩石化学特征的研究 ,认为富碱岩体 (脉 )由正长 (斑 )岩、二长斑岩、花岗斑岩及相关的火山岩组成 ,具有多次活动的特征 ,并形成区内富有特色的岩浆岩系列 ;该系列岩浆岩以富碱高钾为突出特点 ,具有正常的岩浆演化趋势 ,不同岩带岩石地质学和岩石化学方面有区域性变化规律。     

鄂尔多斯盆地西缘桌子山地区石峡谷剖面中奥陶统克里摩里组下段等深流深水水道沉积

鄂尔多斯盆地西缘桌子山地区中奥陶统克里摩里组下段以深灰色薄—中层石灰岩夹灰黑色极薄层泥岩为特征,石灰岩单层略显透镜状且基本未受后期成岩作用改造,其中石峡谷剖面垂向上特征变化明显,是研究该组沉积过程的理想剖面。本次研究在详细的野外观察基础上,依据岩石特征和沉积构造进一步确认克里摩里组深水斜坡沉积背景和等深流沉积,同时详细研究了薄—中层石灰岩的充填特征和形态特征,探讨其水动力特征和沉积机制。结果表明: (1)在粉晶石灰岩和灰泥石灰岩中,晶粒呈散点状分布,粉晶之间为灰泥充填,同时岩层内部具有不均一性,粗粉晶、细粉晶和灰泥呈相间分布;(2)石灰岩主要发育和单层内粒度(方解石晶粒)变化有关的沉积构造,包括具有双向递变特征的粒序层、条带状构造和水平层—均匀层—水平层序列;(3)石灰岩层中透镜体发育,包括薄层中的小型连续透镜体、中层(一般小于30^cm)中的长透镜体以及由多个石灰岩层组成的透镜体,后者侧向上尖灭于页岩或地形高处,其内部单个岩层可呈对称性尖灭;(4)剖面上发育单层石灰岩厚度向上变薄的垂向序列以及由该序列组成的石灰岩叠置层。结合已有研究成果认为: 克里摩里组下段薄—中层石灰岩沉积于深水底流发育环境,其水动力具有低速、弱—强—弱周期变化和空间上受限的特征,应为等深流水道沉积,其沉积机制可分为3个阶段,即等深流作用前的清水钙质沉积、等深流作用期间对沉积物的改造和等深流作用后的浑水泥质沉积。