秦楼铜金矿成矿控制条件及矿床成因分析

秦楼铜金矿区位于淮北铁铜金最有利的成矿区三铺岩体北接触带东段,以金、铜矿为主,并含有多种金属元素。本文对秦楼铜金矿的矿床特征、成因以及控制因素做了分析与研究。     

Estimating ground water discharge by hydrograph separation

Iron Mountain is located in the West Shasta Mining District in California. An investigation of the generation of acid rock drainage and metals loading to Boulder Creek at Iron Mountain was conducted. As part of that investigation, a hydrograph separation technique was used to determine the contribution of ground water to total flow in Boulder Creek. During high-flow storm events in the winter months, peak flow in Boulder Creek can exceed 22.7 m3/sec, and comprises surface runoff, interflow, and ground water discharge. A hydrograph separation technique was used to estimate ground water discharge into Boulder Creek during high-flow conditions. Total ground water discharge to the creek approaches 0.31 m3/sec during the high-flow season. The hydrograph separation technique combined with an extensive field data set provided reasonable estimates of ground water discharge. These estimates are useful for other investigations, such as determining a corresponding metals load from the metal-rich ground water found at Iron Mountain and thus contributing to remedial alternatives.     

Thomson Thick X-Ray Absorption in a Broad Absorption Line Quasar, PG 0946+301

We present results of new ASCA observations of the low-luminosity active galactic nucleus (LLAGN) NGC 4579 obtained on 1998 December 18 and 28, and we report on the detection of variability of an iron K emission line. The X-ray luminosities in the 2-10 keV band for the two observations are nearly identical (LX approximately 2x1041 ergs s(-1)), but they are approximately 35% larger than that measured in 1995 July by Terashima et al. An Fe K emission line is detected at 6.39+/-0.09 keV (source rest frame), which is lower than the line energy 6.73+0.13-0.12 keV in the 1995 observation. If we fit the Fe lines with a blend of two Gaussians centered at 6.39 and 6.73 keV, the intensity of the 6.7 keV line decreases, while the intensity of the 6.4 keV line increases, within an interval of 3.5 yr. This variability rules out thermal plasmas in the host galaxy as the origin of the ionized Fe line in this LLAGN. The detection and variability of the 6.4 keV line indicates that cold matter subtends a large solid angle viewed from the nucleus and that it is located within approximately 1 pc from the nucleus. It could be identified with an optically thick standard accretion disk. If this is the case, a standard accretion disk is present at the Eddington ratio of Lbol/LEdd approximately 2x10-3. A broad disk-line profile is not clearly seen, and the structure of the innermost part of accretion disk remains unclear.     

Water Ice in 2060 Chiron and Its Implications for Centaurs and Kuiper Belt Objects

The deviation from the power-law decline of the optical flux observed in GRB 970228 and GRB 980326 has been used recently to argue in favor of the connection between gamma-ray bursts and supernovae. We consider an alternative explanation for this phenomenon, based on the scattering of a prompt optical burst by 0.1 M middle dot in circle dust located beyond its sublimation radius 0.1-1 pc from the burst. In both cases, the optical energy observed at the time of the first detection of the afterglow suffices to produce an echo after approximately 20-30 days, as observed. Prompt optical monitoring of future bursts and multiband photometry of the afterglows will enable us to test simple models of dust reprocessing quantitatively and to predict source redshift.     

Chemistry of the organic-rich hot core G327.3-0.6

We present gas-phase abundances of species found in the organic-rich hot core G327.3-0.6. The data were taken with the Swedish-ESO Submillimetre Telescope (SEST). The 1-3 mm spectrum of this source is dominated by emission features of nitrile species and saturated organics, with abundances greater than those found in many other hot cores, including Sgr B2 and OMC-1. Population diagram analysis indicates that many species (CH3CN, C2H3CN, C2H5CN, CH3OH, etc.) have hot components that originate in a compact (~2") region. Gas-phase chemical models cannot reproduce the high abundances of these molecules found in hot cores, and we suggest that they originate from processing and evaporation of icy grain mantle material. In addition, we report the first detection of vibrationally excited ethyl cyanide and the first detection of methyl mercaptan (CH3SH) outside the Galactic center.     

蒙大拿州Beartooth山脉北Snowy地块的太古代构造

位于蒙大拿州Beartooth山脉北西部的北Snowy地块主要是由七个太古代岩性单元组成:(1)Mouny Cowen眼球状花岗质片麻岩;(2)由大量长英质片麻岩、砂屑片岩、角闪岩和铁建造组成的副片麻岩系;(3)眼球状构造的花岗质凝灰岩;(4)千枚状Dauis Geeek片岩;(5)奥长花岗质片麻岩—角闪石岩杂岩;(6)Pine Greek推覆杂岩,为一具有闪岩核和两翼对称出现大理岩和石英岩的区域等斜构造;(7)上壳混合杂岩,由石英岩—闪岩组合和具有花岗质物质间层贯入上壳岩的非均质片麻岩组成。每个单元有其特征的岩性组合、变质级和构造样式。大多数单元之间的接触部位以糜棱岩(被认为是韧性断层的产物)和变质级的突变为标志。在四个构造作用最强的单元中,这些变化造成变质级的逆向和不连续增加。这些单元现在的轮廓最好解释为,在2.74Ga和2.56Ga前,变质期后,可能沿走向滑移断层和逆冲断层的构造拼合。从更大的范围看,这一地区位于怀俄明州北部两个截然不同地体的边界上(副片麻岩—Mount Cowan接触)。一个为东西的晚太古代侵入地体。另一个是西面的太古代变质上壳岩地体。NSB和Beartooth山脉的其它部分的关系表明,这个边界产生在晚太古代造山运动期间,与现代碰撞环境有许多相似性。