热带雨林景观土壤测量采样深度与样品粒级试验研究——以加纳国雅卡锰金矿为例

加纳国雅卡锰金矿床位于著名的阿散蒂金矿带上。在该成矿带进行土壤测量采样深度、样品粒级试验以及方法技术的适应性和有效性研究,可为下一步开展大面积土壤地球化学测量提供技术依据,从而圈定可靠土壤地球化学异常。本文采用的工作方法为土壤垂向剖面法,选择有代表性的地段进行试验研究,结果显示在已知矿上方获得了明显的土壤地球化学异常。通过实验研究,选取土壤测量采样深度60～80 cm,截取样品粒级-4～+20目,获得了可靠、明显的土壤地球化学异常。研究证明该方法具有显著的地球化学找矿效果。     

南秦岭柞水-山阳矿集区龙头沟金矿床硫化物微量元素和硫同位素地球化学特征

龙头沟矿床是南秦岭柞水-山阳矿集区内新发现的中型金矿床。本文以矿床中的黄铁矿及黄铜矿为研究对象,在详细的室内、外研究的基础上,采用LA-ICPMS和LA-MC-ICPMS测试方法对成矿期不同阶段的硫化物进行微量元素及硫同位素成分研究。结果表明,黄铁矿Co含量为(0.33～183.93)×10~(-6),Co/Ni比值介于0.035～1.9之间,且Co/Ni比值多小于1,表明黄铁矿可能形成于中低温环境,多具有沉积成因和沉积改造成因微量元素特征,黄铁矿中Au的富集可能与中低温多期岩浆热液活动有关。第Ⅰ阶段硫化物的δ~(34)S值变化范围为0.1‰～3.74‰,均值为1.71‰,显示出幔源硫特征;而第Ⅱ阶段的δ~(34)S=-13.99‰～13.35‰,均值为2.17‰,介于0±3‰之间,显示该阶段可能是幔源与赋矿围岩发生水岩反应;第Ⅲ阶段δ~(34)S=7.44‰～14.72‰,低于围岩(δ~(34)S=18.14‰～20.54‰),显示该阶段可能有地层硫参与,是上升的成矿流体与赋矿围岩发生水岩反应,硫同位素特征指示硫可能由幔源和赋矿围岩混合而成。     

特提斯喜马拉雅中东部桑秀组酸性火山岩岩石成因:东冈瓦纳大陆裂解的响应?

关于特提斯喜马拉雅构造带中东部地区桑秀组酸性火山岩是否是地壳深熔形成以及与东冈瓦纳大陆裂解事件存在关联长期以来有较大争议,以羊卓雍错地区桑秀组酸性火山岩为研究对象,在详实的野外地质调查及样品采集基础上,通过室内镜下岩石学特征、LA-ICP-MS锆石U-Pb定年、全岩地球化学和锆石Hf同位素地球化学研究.结果表明:羊卓雍错地区桑秀组底部两个酸性火山岩样品（RYA01、DYA01）加权平均年龄为139.1±1.3 Ma（1σ,MSWD=1.08）和137.3±1.4 Ma（1σ,MSWD=0.98）,代表了特提斯喜马拉雅地区早白垩世时期火山活动.岩石地球化学和Hf同位素地球化学特征表明,酸性火山岩具有高含量的SiO₂、低镁指数值、较高的A/CNK比值,富集Al、LREE和Th,强烈亏损Nb,锆石ε_Hf（t）值介于-20.1~-10.5之间,平均值为-13.5.综合研究表明,羊卓雍错地区桑秀组酸性火山是印度大陆北缘伸展减薄的环境下幔源岩浆底侵诱发上覆地壳并发生部分熔融形成的岩浆产物,结合酸性火山岩锆石年龄结果以及前人对东冈瓦纳大陆研究成果,认为羊卓雍错地区桑秀组酸性火山岩与东冈瓦纳大陆裂解有关,属于Kerguelen地幔柱岩浆活动早期产物.      

河南省冰雹时空分布及天气形势特征

利用河南省121个气象台站1971—2010年共40a的冰雹资料,应用统计学方法,分析了河南省冰雹日的年际、月际和日变化特征,以及降雹的落区和范围等空间分布特征等,结果表明:河南省冰雹的年际变化较不稳定,20世纪80年代到90年代中期冰雹日出现较多,到21世纪初又出现一个小高峰,2006年之后则保持较低值;每年4—8月为河南省冰雹多发期,而冰雹在一天之内绝大部分发生在午后到傍晚,这是由形成冰雹的热力条件决定的。40a间冰雹主要发生在河南省中北部、西部和西南部山区,而在东部和东南部的平原地区冰雹发生次数较少。通过对1999—2010年45个冰雹日天气形势的分析发现,河南省易产生冰雹的4种主要天气形势分别为西北气流型、东北冷涡型、华北冷涡型和低槽型,西北气流型造成的冰雹日为最多,低槽型冰雹日最少,不同天气形势背景下的降雹落区有较大差异。     

南极长城站气侯特征及其趋势

利用我国南极长城站1985-2013年地面气象观测要素,分析了气候特征及其变化趋势,将有助于我们对最近30年亚南极地区气候变化的认识。结果表明,年平均气温为-2.2℃,变化速率为0.07℃/10a,呈升高趋势但不显著。年平均气压为989.3hpa,呈下降趋势,速率为-0.19hpa/10a。年平均相对湿度为89%,变化速率为0.34%/10a,上升趋势不明显。年降水量为539.3mm,变化速率为32.5mm/10a,呈明显增加趋势。年平均风速为7.5m.s-1,变化速率很小,盛行风向为西北和东南2个方向。     

国家级太阳辐射测量标准及其质量控制

太阳辐射测量标准仅采取定期参加国际比对的溯源方法不能完全满足质量保证的要求。只有联合国际比对和期间核查的控制方法,才能确保测量标准的测量不确定度持续控制在误差允许范围之内。我国太阳辐射测量标准与世界辐射测量基准 (WRR) 比对结果的不确定度为0.17%,满足世界气象组织 (WMO) 要求,并达到世界先进水平。为了保证在两次国际周期比对间隔之间的准确可靠,并保证其处于良好置信度的校准状态,定期对测量标准的重复性和稳定性进行期间核查, 以图形记忆方式对太阳辐射测量标准的测量过程进行连续和长期的统计控制。通过期间核查,保证了太阳辐射测量标准的重复性不大于0.1%,年稳定性小于0.25%,未超出控制界限且分布呈随机状态,保证了测量过程处于稳定受控状态,满足建标要求。     

同化雷达估算降水率对暴雨预报的影响

选取2009年3月28日广东省广州市大暴雨过程,考察了变分校准前后Z-I关系估算雷达降水率的区别。变分校准后的降水率资料具有较高的单点精度与合理的梯度分布。降水率资料能够反映大气动力特征和水汽分布等重要信息,是模拟中小尺度系统的关键因子。基于GRAPES (Global/Regional Analysis and Prediction System) 区域三维变分系统,将FSU (Florida State University) 对流参数化方案作为观测算子的同化试验指出,同化降水率资料后同时增强了低层大气的辐合和高层大气的辐散,从而使整层气柱的不稳定能量增加。沙氏指数和K指数诊断分析也表明,同化降水率资料后有利于触发强对流天气。此外,低空辐合有利于水汽垂直输送,维持对流发展,改进降水模拟。逐小时数值模拟结果表明:同化校准后的雷达估算降水率不仅可以改进降水分布,而且使中尺度对流系统的发展和消亡清晰地表现出来。     

Constraints on biotic and abiotic role in the formation of Fe-Si oxides from the PACMANUS hydrothermal field

Fe-Si oxide deposits were recovered from the PACMANUS (Papua New Guinea-Australia-Canada-Manus) hydrothermal field in Eastern Manus basin. Samples were loose and fragile. Optical and scanning electron microscopy showed that the samples had abundant rod-like or twisted filamentous and granular structures. Electron probe microanalysis revealed that these filaments and grains were mainly composed of Fe and Si. The presence of spherical grains on the surface of the filaments suggests the intergrowth of biotic and abiotic reactions. Biotic and abiotic kinetics competition always exists in the redox gradient. Based on the physico-chemical conditions of PACMANUS hydrothermal fluids, we calculated a strict abiotic oxidation rate of Fe²⁺ to Fe³⁺, which is approximately 0.0123 g/min. If the fluids had been erupting consistently and the concentration of Fe²⁺ was constant, 3.232 kg per year of Fe would be deposited in this vent. The amount of Fe oxides around the studied vent was larger than the amount determined by strict abiotic kinetic calculation. Bacteria may also play an important role in Fe oxidation. A mesh-like microenvironment constructed by biogenic filaments ensured adequate Fe²⁺ and low oxygen content for the growth of bacteria. Moreover, this structure promoted the deposition of abiotic Fe-Si oxides.     

Effects of salinity on survival,feeding behavior and growth of the juvenile swimming crab,Portunus trituberculatus (Miers, 1876)

Effect of salinity on survival,feeding behavior and growth of juvenile swimming crab P ortunus trituberculatus was investigated under 5 salinity levels of 5,10,20,30 and 40. The results show that the crab juveniles fed 2 or 3 times at the salinity 20 and 30,each lasted for about 25 minutes,for a total feeding time of 73.2±22.65 minutes per day. At these salinities,there were significantly higher in the frequency of feeding and in total feeding time than those at lower salinities of 5 and 10. All crab juveniles moulted when reared at a salinity of 20 during the 5 days duration of the experiment,which is significantly higher than those at other salinities. All juveniles survived at salinity 20,and the survivorship was not significantly different from that at 30,but was signif icantly higher than those at other salinities. The crab juveniles reared at a salinity of 20 had the highest value of food ration of 0.190 8±0.011 3 g/g BW,average body weight gain of 0.796±0.128 g,gain rate of 87%–96%,and food conversion ratio of 1.20±0.09. There was no significant difference in the values found between 20 and 30 but these values were significantly lower than that at the other salinities( P 0.05). Highest activities of digestive enzymes(Amylase,Protease,Lipase) and lowest activities of protective enzymes(SOD,PO,CAT) were also obtained on crab juveniles reared at salinity of 20.