黔西南卡林型金矿床与区域古油藏的关系:来自流体包裹体气相组成和沥青拉曼光谱特征的证据   总被引：2，自引：2，他引：0  

靳晓野  李建威  HOFSTRA Albert  MARSH Erin  刘建中  杨梧 《岩石学报》2016,32(11):3295-3311

黔西南地区是世界第二大卡林型金矿床集中区,同时也发育有大量古油藏,二者空间关系密切,但是否具有成因联系目前尚不清楚且存在较大争议。本文报道该区典型金矿床与成矿有关的热液矿物中流体包裹体的气相组成和高品位金矿石中沥青的激光拉曼光谱分析结果,以探讨含有机质流体与金成矿作用之间的关系。研究表明,虽然含砷富金黄铁矿、石英、方解石、萤石和雄黄等热液矿物形成于不同的成矿阶段,但其中流体包裹体的有机气相组分种类、含量及相对比例整体较为一致,表明成矿流体中的有机络离子团在成矿作用过程中没有发生明显的分解或重组,进而说明黔西南卡林型金矿成矿作用过程中有机质并未以有机络离子团的形式对金进行有效搬运或其搬运金的能力非常有限。在N2/Ar-CO2/CH4流体来源判别图解中,各蚀变矿物中的流体包裹体气相组成主要落在循环的大气降水区域,经大气水区域向岩浆流体区域延伸,整体上构成一条非常好的线性分布趋势,暗示成矿流体可能起源于深部岩浆但在演化过程中有大量循环大气水的加入。水银洞金矿床的1件石英样品偏离上述趋势线并向有机流体方向偏移,可能反映了流体迁移过程中有机质的加入。该区金矿床的矿石中均不同程度地发育浸染状沥青,不同矿床中沥青的激光拉曼光谱特征基本一致,说明该区金矿床中的沥青具有相同成因。根据沥青激光拉曼光谱特征地质温度计反演计算的成矿早阶段流体温度为317~336℃,明显高于区域古地温温度(160~250℃)以及区域古油藏的流体包裹体均一温度(73~175℃),说明该区卡林型金矿床的成矿热源与区域古地温无关。对区域地质及近年来地球物理与地球化学最新成果的综合分析表明,该区卡林型金矿床可能是叠加在区域古地温场之上的深部岩浆活动远端低温热液成矿作用的产物,与金矿床空间关系密切的有机质可能为来自先存古油藏并沿控矿构造发生逃逸的油气物质裂解产物,金成矿与区域古油藏之间不存在成因联系。  相似文献   

Effects of single and combined exposures to benzo(a)pyrene and 3,3'4,4'5-pentachlorobiphenyl on EROD activity and development in Fundulus heteroclitus   总被引：2，自引：0，他引：2  

Wassenberg DM  Swails EE  Di Giulio RT 《Marine environmental research》2002,54(3-5):279-283

The goal of this study was to assess the interactive effects of a polynuclear aromatic hydrocarbon (PAH), benzo(a)pyrene (BaP), and a co-planar halogenated aromatic hydrocarbon (HAH), 3,3'4,4'5-pentachlorobiphenyl (PCB 126) on ethoxyresorufin-O-deethylase (EROD) activity and occurrence of deformities in Fundulus heteroclitus. While each compound administered alone elicited dose-dependent increases in EROD activity, the combined treatment of these two compounds generally did not elicit an additive EROD response. There was a significant correlation between deformity occurrence and EROD induction in embryos dosed with PCB alone but not for embryos dosed with BaP alone, or a combination of BaP and PCB 126.  相似文献   

Decadal-scale sediment dynamics and environmental change in the Albemarle Estuarine System, North Carolina     

D. Reide Corbett  Dave Vance  Erin Letrick  David Mallinson  Stephen Culver 《Estuarine, Coastal and Shelf Science》2007,71(3-4):717-729

During the summer of 2001, several short cores (<50 cm) were collected in the Albemarle Estuarine System (AES). Down-core measurements for radiochemical tracers (²¹⁰Pb, ¹³⁷Cs) and organic matter signatures (δ¹³C, δ¹⁵N, C:N ratio, and LOI) have been used to elucidate potential temporal changes in fluxes and cycles of organic matter in the AES. Pb-210 geochronology indicates temporal and spatial variations in sediment deposition rates (0.08–0.57 cm y⁻¹) with highest rates near the AES western limit relative to the rest of the estuary. Low accumulation rates, deficient excess ²¹⁰Pb inventories, and near linear ¹³⁷Cs profiles throughout the AES suggest that sediments are resuspended by wind-generated waves and currents and flushed from the system by river discharge and wind-tides, probably to Pamlico Sound to the south. Sediments in the AES are accumulating at rates less than the current rate of relative sea-level rise for this region except in protected portions of the estuary. Thus sediment accumulation in the AES is controlled in the short term by storm wave-base and in the long term by the creation of accommodation space by basin subsidence and sea-level rise. The geochemical and sedimentological data characterize the evolution of the Albemarle Sound and associated tributaries over the past 200–300 years. The majority of cores collected throughout the system show a significant decrease in ¹³C and increase in ¹⁵N isotopic signatures up-core. Thus, the estuarine system of eastern North Carolina has changed from a marine-influenced, high brackish environment to the modern-day system, which is a highly variable, terrestrially influenced, low brackish environment.  相似文献   

P -T paths from anatectic pelites   总被引：2，自引：1，他引：1  

Frank S. Spear  Matthew J. Kohn  John T. Cheney 《Contributions to Mineralogy and Petrology》1999,134(1):17-32

A relatively simple petrogenetic grid for partial melting of pelitic rocks in the NCKFMASH system is presented based on the assumption that the only H₂O available for melting is through dehydration reactions. The grid includes both discontinuous and continuous Fe-Mg reactions; contours of Fe/(Fe+Mg) for continuous reactions define P-T vectors along which continuous melting will occur. For biotite-bearing assemblages (garnet+biotite + sillimanite + K-feldspar + liquid and garnet + biotite + cordierite + K-feldspar + liquid), Fe/(Fe+Mg) contours have negative slopes and melting will occur with increasing temperature or pressure. For biotite-absent assemblages (garnet + cordierite + sillimanite + K-feldspar + liquid or garnet + cordierite + orthopyroxene + K-feldspar + liquid) Fe/(Fe + Mg) contours have flat slopes and melting will occur only with increasing pressure. The grid predicts that abundant matrix K-feldspar should only be observed if rocks are heated at P < 3.8 kbar, that abundant retrograde muscovite should only be observed if rocks are cooled at P > 3.8 kbar, and that generation of late biotite + sillimanite replacing garnet, cordierite, or as selvages around leu- cosomes should be common in rocks in which melt is not removed. There is also a predicted field for dehydration melting of staurolite between 5 and 12 kbar. Textures in migmatites from New Hampshire, USA, suggest that prograde dehydration melting reactions are very nearly completely reversible during cooling and crystallization in rocks in which melt is not removed. Therefore, many reaction textures in “low grade” migmatites may represent retrograde rather than prograde reactions. Received: 5 March 1998 / Accepted: 7 August 1998  相似文献   

武隆喀斯特及其地壳抬升性质解读   总被引：5，自引：3，他引：2  

朱学稳  陈伟海  Erin Lynch 《中国岩溶》2007,26(2):119-125

在特定的地质结构及峡谷水文网分布条件下,武隆喀斯特以独立发育的诸多包气带喀斯特系统为主要特征,而且不同喀斯特系统间的结构与形态组成差异甚大。喀斯特系统的分析可解读相适应的地壳运动性质是: 自新近纪末期以来,地壳运动只有上升没有下降过程;前80～ 100万年为持续上升,即几乎没有相对稳定的经历;继后是间歇性抬升与相对稳定,似以后者占优;分布于深切峡谷相对高度150～ 300m间的大型成层性洞穴,主要发育于中更新世;晚更新世以来的上升与相对稳定彼此平分秋色。   相似文献   

Experimental implementation and verification of multi‐degrees‐of‐freedom effective force testing          下载免费PDF全文

Narutoshi Nakata  Erin Krug  Aaron King 《地震工程与结构动力学》2014,43(3):413-428

This paper presents an experimental implementation and verification of multi‐degrees‐of‐freedom effective force testing (MDOF‐EFT). An experimental setup that consists of a two‐degrees‐of‐freedom structural system and two hydraulic actuators at the Johns Hopkins University was utilized in this study. First, experimental system identification was performed to develop compatible analytical models for the multi‐input and multi‐output systems. Dynamics of the control plant, that is, the valve‐to‐force relations, were modeled with a rational polynomial transfer function matrix and delay components. By using the analytical model, a centralized decoupling loop‐shaping force feedback controller was designed such that the forces are uncoupled and the loop transfer functions have desirable dynamic characteristics in the frequency domain. Then, a series of harmonic force and earthquake simulation tests were performed to assess capabilities and limitations of MDOF‐EFT. Experimental results showed that the dynamic forces in the two actuators were accurately controlled to provide tracking while the system was stable and robust for the entire period of the experiment. Furthermore, earthquake simulation tests with increased levels of the reference forces demonstrated the feasibility of MDOF‐EFT with highly nonlinear test structures. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Affordable Enteric Virus Detection Techniques Are Needed to Support Changing Paradigms in Water Quality Management          下载免费PDF全文

Erin M. Symonds  Mya Breitbart 《洁净——土壤、空气、水》2015,43(1):8-12

In light of water quality monitoring paradigms shifting to a more holistic approach, it is essential that environmental microbiologists embrace new methodological developments in clinical virology to create rapid, laboratory‐free methods for the identification of wastewater pollution. It is widely accepted that routine monitoring of fecal indicator bacteria (FIB) does not adequately reflect human health risks associated with fecal pollution, especially risks posed by viruses. Enteric viruses are typically more resistant to wastewater treatment and persist longer in the environment than FIB. Furthermore, enteric viruses often have extremely low infectious doses. Currently, the incorporation of sanitary surveys, short‐term monitoring of reference pathogens, exploratory quantitative microbial risk assessments, and predictive ecological models is being championed as the preferred approach to water management. In addition to improved virus concentration methods, simple, point‐of‐use tests for enteric viruses and/or improved viral indicators are needed to complement this emerging paradigm and ensure microbial safety worldwide.

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Measuring Concentrations of Dissolved Methane and Ethane and the 13C of Methane in Shale and Till          下载免费PDF全文

M. Jim Hendry  S. Lee Barbour  Erin E. Schmeling  Scott O. C. Mundle 《Ground water》2017,55(1):119-128

Baseline characterization of concentrations and isotopic values of dissolved natural gases is needed to identify contamination caused by the leakage of fugitive gases from oil and gas activities. Methods to collect and analyze baseline concentration‐depth profiles of dissolved CH₄ and C₂H₆ and δ¹³C‐CH₄ in shales and Quaternary clayey tills were assessed at two sites in the Williston Basin, Canada. Core and cuttings samples were stored in Isojars^® in a low O₂ headspace prior to analysis. Measurements and multiphase diffusion modeling show that the gas concentrations in core samples yield well‐defined and reproducible depth profiles after 31‐d equilibration. No measurable oxidative loss or production during core sample storage was observed. Concentrations from cuttings and mud gas logging (including IsoTubes^®) were much lower than from cores, but correlated well. Simulations suggest the lower concentrations from cuttings can be attributed to drilling time, and therefore their use to define gas concentration profiles may have inherent limitations. Calculations based on mud gas logging show the method can provide estimates of core concentrations if operational parameters for the mud gas capture cylinder are quantified. The δ¹³C‐CH₄ measured from mud gas, IsoTubes^®, cuttings, and core samples are consistent, exhibiting slight variations that should not alter the implications of the results in identifying the sources of the gases. This study shows core and mud gas techniques and, to a lesser extent, cuttings, can generate high‐resolution depth profiles of dissolved hydrocarbon gas concentrations and their isotopes.  相似文献   

Variation in groundwater salinity in a tidal salt marsh basin,North Inlet Estuary,South Carolina     

Erin S. Carter  Scott M. White  Alicia M. Wilson 《Estuarine, Coastal and Shelf Science》2008

Groundwater flow of freshwater from upland forests into salt marshes is influenced by hydrologic forces that operate over a wide range of temporal scales, including storm events, tidal fluctuations, seasonal variations in rainfall and evapotranspiration (ET). Groundwater salinity can be a useful first order indicator of the balance between these flow processes. A dipole-dipole electrical resistivity survey was conducted approximately monthly during 2005 to measure groundwater salinity across a portion of Crabhaul Creek, a tidal salt marsh basin at the boundary of the upland forest and the North Inlet marsh in South Carolina. The monthly electrical resistivity surveys were designed to provide a detailed, spatially continuous measurement of subsurface conductivity to a depth of 4 m in order to further investigate the seasonal variation in groundwater salinity. Resistivity models were corroborated by simultaneous measurements of salinity in nearby piezometers. The freshwater-brackish water interface was clearly imaged by the resistivity. Movement of this interface occurs on a timescale of months rather than a regular seasonal variation. The average salinity in the marsh basin is highest in late Summer (July–August) when ET is highest, and lowest during the Winter (November–December). The position of the brackish-freshwater interface changes, but is not well correlated to local rainfall or tidal cycles except under specific circumstances. A steady-state hydrological model correctly predicts the average position of the freshwater-brackish interface and suggests a linear relationship between the height of the water table and the location of the interface. These results suggest a complex relationship between precipitation events and groundwater flow from the forest into the marsh.  相似文献   

Bioaugmentation in a Well‐Characterized Fractured Rock DNAPL Source Area          下载免费PDF全文

Charles E. Schaefer  Graig M. Lavorgna  Erin B. White  Michael D. Annable 《Ground Water Monitoring & Remediation》2017,37(2):35-42

A field demonstration was performed at Edwards Air Force Base to assess bioaugmentation for treatment of a well‐characterized tetrachloroethene (PCE) dense nonaqueous phase liquid (DNAPL) source area in fractured rock. Groundwater recirculation was employed to deliver remedial amendments, including bacteria, to facilitate reductive dechlorination and enhance DNAPL dissolution. An active treatment period of 9 months was followed by a 10‐month posttreatment rebound evaluation. Dechlorination daughter products were observed in both the shallow and deep fracture zones following treatment. In the shallow fracture zone, the calculated DNAPL mass removed was approximately equal to the DNAPL mass estimated using partitioning tracer testing, and no rebound in chlorinated ethenes or ethene was observed during the posttreatment period. A maximum DNAPL dissolution enhancement factor of 5 was observed in the shallow fracture zone. In the deep fracture zone, only approximately 45% of the DNAPL mass—as estimated via partitioning tracer testing—was removed and rebound in the total molar chlorinated ethenes + ethene was observed. The difference in behavior between the shallow and deep fracture zones was attributed to DNAPL architecture and the fracture flow field.  相似文献