四川盆地上三叠统须家河组高分辨率层序地层研究

为了进一步认识四川盆地须家河组的层序格架和时空分布,基于高分辨率层序地层学及沉积学相关理论,通过露头剖面、钻井岩心的观察及测井、地震等资料的分析,开展了四川盆地须家河组层序地层研究,结果发现盆地内虽然具有构造复杂、物源多样、岩相不均、组名不统一的特点,但依然具有全盆地范围内可追溯的不整合面和湖泛面。通过层序界面追踪及沉积旋回分析,将四川盆地须家河组划分为3个超长期基准面旋回、6个长期基准面旋回及21个中期基准面旋回,并建立了盆地内各级旋回的对比关系。通过全盆地对比结果表明,须家河组在南北方向上各级旋回个数变化不大,沉积厚度相对稳定;东西方向上旋回变化复杂,西部缺失LSC6旋回和大部分LSC5旋回,东部则缺失大部分LSC1旋回,由于沉降与沉积中心位于龙门山前缘坳陷,盆地近西部沉积速率极高,整体的沉积体展布呈现西厚东薄的楔形体形态特征。在层序对比研究的基础上,尝试性地建立了年代地层格架,通过层序地层学与年代地层学、古生物地层学的综合对比,推测了各旋回的相对年龄值以及不整合面的沉积间断时间,为四川盆地须家河组下一步油气资源探勘开发提供了理论支持。     

Perfectly matched layer for an elastic parabolic equation model in ocean acoustics

The perfectly matched layer(PML) is an effective technique for truncating unbounded domains with minimal spurious reflections. A fluid parabolic equation(PE) model applying PML technique was previously used to analyze the sound propagation problem in a range-dependent waveguide(Lu and Zhu, 2007). However, Lu and Zhu only considered a standard fluid PE to demonstrate the capability of the PML and did not take improved one-way models into consideration. They applied a [1/1] Padé approximant to the parabolic equation. The higher-order PEs are more accurate than standard ones when a very large angle propagation is considered. As for range-dependent problems, the techniques to handle the vertical interface between adjacent regions are mainly energy conserving and single-scattering. In this paper, the PML technique is generalized to the higher order elastic PE, as is to the higher order fluid PE. The correction of energy conserving is used in range-dependent waveguides. Simulation is made in both acoustic cases and seismo-acoustic cases. Range-independent and range-dependent waveguides are both adopted to test the accuracy and efficiency of this method. The numerical results illustrate that a PML is much more effective than an artificial absorbing layer(ABL) both in acoustic and seismo-acoustic sound propagation modeling.     

宁芜矿集区雍镇矿田深部铜金矿成矿机制

宁芜地区在过去相当长的一段时间内被认为铜、金矿找矿前景不大,但是,近年来在该区勘查工作中发现,雍镇矿田具有良好的铜金矿成矿前景,目前已发现小六房金矿、夏家庄铜矿等矿点。成矿物质来源应为深部,与燕山期整个中国东部岩石圈大灾变、地幔上涌等构造热事件有关,与岩石圈减薄、地幔上涌关系密切。含矿岩浆流体在上升过程中,由于顶部盖层压力大于岩浆爆破应力,产生气爆甚至是液爆,形成角砾岩筒,它与该区断裂、褶皱构造一起,为区内含铜、金矿液的运移及沉淀提供了良好的运移及储存空间,并在有利部位富集成矿。     

琼东南盆地深水东区渐新统烃源岩发育模式

琼东南盆地深水东区勘探程度低,钻井样品受油基泥浆污染严重,目前关于该区浅海相和海陆过渡相烃源岩的有机地球化学研究较为局限。通过对深水东区渐新统受油基泥浆污染的泥岩岩屑进行有效地洗油实验及有机地球化学分析测试,结合东部浅水区渐新统烃源岩样品的有机岩石学、有机地球化学分析测试等地质资料,系统剖析了深水东区渐新统不同沉积相烃源岩的地球化学特征、发育控制因素和发育模式。研究结果认为,琼东南盆地深水东区渐新统烃源岩的发育模式可分为海陆过渡相三角洲前缘模式和浅海相模式。海陆过渡相三角洲前缘烃源岩为中等—高有机质丰度,有机质类型为Ⅲ型,具有Pr/Ph普遍大于3、(nC21+nC22/nC28+nC29)普遍小于1.2、高OL/C30H、高T/C30H、低C23TT/C30H、低C27ST/C29ST和相对较低的Ga/C30H、C35/C3422S的特征,烃源岩的TOC和硫含量相关性极好,沉积水体为氧化性淡水—半咸水环境。三角洲前缘烃源岩的TOC和母源输入参数相关关系较好,而与Ga/C30H、C35/C3422S参数相关关系较差,说明三角洲前缘烃源岩的有机质丰度主要受陆源有机质输入的控制。浅海相烃源岩有机质丰度中等,有机质类型为Ⅱ2~Ⅲ型,具有Pr/Ph普遍小于3、(nC21+nC22/nC28+nC29)普遍大于1.5、低OL/C30H、低T/C30H、高C23TT/C30H、高C27ST/C29ST和相对较高的Ga/C30H、C35/C3422S的特征,且烃源岩的TOC和硫含量相关性较差,沉积水体为弱氧化性半咸水—咸水沉积环境。浅海相烃源岩的TOC和母源输入参数、Ga/C30H、C35/C3422S等相关关系均较好,说明浅海相烃源岩有机质丰度受水生有机质输入和弱氧化性半咸水—咸水沉积环境控制。滨海相烃源岩的有机质丰度为差—中等,有机质类型以Ⅲ型为主,且TOC受母质来源或沉积水体的氧化还原性影响较小,其烃源岩发育模式是一种破坏性模式。     

厚层风积黄土覆盖区金矿脉的壤中气汞异常特征及评价

赤峰市莲花山金矿区南部为大片风积黄土覆盖区，壤中气汞测量圈出了许多气汞异常，其中在已开采的４号、５号金矿脉上，气汞异常的形态、规模和强度都较好地反映了矿体的产状和规模。新的工业金矿体的发现，更加证实了壤中气汞测量找金矿脉的有效性。通过壤中气汞异常的评价，认为４号矿脉的北部，５号矿脉的南部，Ｈｇ２号异常的南部及Ｈｇ３号异常的深部有较好的开采远景，而４１号、１５号、２０号石英脉则无工业价值。     

含锑地质试样中金的测定

本文考查了Sb对氢醌法测Au的影响。实验证明,Sb的存在使Au的结果偏高,酒石酸钾钠只掩蔽2mg的Sb。对于含Sb试样,灼烧除Sb并不完全,即使经活性炭吸附Au处理后的待测样中Sb仍存在。本文采用HBr辅助除Sb取得良好效果。方法简便、准确性好,Au的回收率在95.5—102.75％范围,试样测定结果与其它方法相符。     

贵州石灰岩和砂岩地区C4和C3植物营养元素的化学计量对N/P比值波动的影响

陆地生态系统植物的生长受到营养元素氮(N)和磷(P)的可利用性的限制。已有的证据表明营养元素的相对丰度将控制生态系统的营养元素循环和能量流动的速度。文章提出如下假设:为了适应环境的变化,植物具有可伸缩性地调整营养元素含量的能力,也就是营养元素化学计量比值变化的能力,植物N/P比值波动的影响不仅来源于N对P的相对可利用性的变化,也来源于其他营养元素化学计量的变化,尤其是与Ca的化学计量的变化。为了验证上述假设,本研究利用3种C₄植物和11种C₃植物,研究了植物N/P化学计量比值的波动随N与Ca和P与Ca化学计量的变化模式:对C₄植物来说,N/P比值的波动主要受生物量P与Ca化学计量变化的影响;而对C₃植物来说,则同时受N与Ca和P与Ca化学计量变化的控制,它们之间的相对控制能力的大小将决定植物N/P比值波动的变化梯度,C₄植物和C₃植物的N/P比值的波动都要受土壤pH值的影响。本研究对了解物种丰度和N对P的相对可利用性、N与Ca,以及P与Ca的化学计量之间关系具有重要意义。     

Variations in Vegetation Net Primary Production in the Qinghai-Xizang Plateau, China, from 1982 to 1999

Vegetation net primary production (NPP) derived from a carbon model (Carnegie–Ames–Stanford Approach, CASA) and its interannual change in the Qinghai-Xizang (Tibetan) Plateau were investigated in this study using 1982–1999 time series data sets of normalized difference vegetation index (NDVI) and paired ground-based information on vegetation, climate, soil, and solar radiation. The 18-year averaged annual NPP over the plateau was 125 g C m⁻² yr⁻¹, decreasing from the southeast to the northwest, consistent with precipitation and temperature patterns. Total annual NPP was estimated between 0.183 and 0.244 Pg C over the 18 years, with an average of 0.212 Pg C (1 Pg = 10¹⁵ g). Two distinct periods (1982–1990 and 1991–1999) of NPP variation were observed, separated by a sharp reduction during 1990–1991. From 1982 to 1990, annual NPP did not show a significant trend, while from 1991 to 1999 a marked increase of 0.007 Pg C yr⁻² was observed. NPP trends for most vegetation types resembled that of the whole plateau. The largest annual NPP increase during 1991–1999 appeared in alpine meadows, accounting for 32.3% of the increment of the whole region. Changes in solar radiation and temperature significantly influenced NPP variation, suggesting that solar radiation may be one of the major factors associated with changes in NPP.     

The partitioning patterns of nutrients between pods and seeds of <Emphasis Type="Italic">Zanthoxylum</Emphasis> fruits impacted by environmental factors

The nutritive quality in plant organs is related to the different partitioning patterns of nutrient resources among the organs under various environmental conditions. This study examined the relationship between the nutritive quality of pods and seeds in Zanthoxylum and environmental factors, such as temperature and preciptation by using numerous samples collected from Southwest China to the East China of Shandong peninsula. The increasing accumulations of N, P and C in seeds implied that the nutritive quality in seeds was higher at the regions with relative higher mean annual temperature (MAT) and mean annual precipitation (MAP), while that in pods was on the contrary. By contrast, pod nutritive content was relatively high, but seed nutritive content was relatively low at the regions with relative high MAT and MAP. In addition, C:N ratio in pods was significantly and negatively correlated with MAT and MAP, while that in seed was significantly and positively correlated with MAT and MAP. The partitioning patterns of N-compounds between pods and seeds reflected different nitrogen translocations in the plant organs under various climate condition. The N:P ratios were negatively correlated with MAP, implying a higher proportional allocation of P to seeds than that of N in the areas with a relative high MAP. Therefore, the strategies to assess pod nutritional quality should be taken into account for nutritive translocation under various environmental conditions.     

基于绿色生物模板电极的微囊藻毒素-LR快速检测

为实现水环境中微囊藻毒素的高性能检测,利用农业废弃物合成了具导电性能的生物炭颗粒,并将其作为导电材料构建了对微囊藻毒素-LR具电化学免疫检测性能的生物模板电极。实验结果表明：该电极具有很好的电催化性能,在电解液中,能够在短时间（5 min）内有效识别微囊藻毒素-LR的存在;利用差分脉冲伏安法检测发现在0.0~5.0 nmol/L的检测范围内毒素浓度与响应电流值呈线性递减关系,且最低检测浓度为0.2 nmol/L。该电极对各类不相关分子及离子具有抗干扰能力,表明了该方法可应用于对微囊藻毒素-LR污染的快速、特异性检测。