The anthropogenic influence on carbonaceous aerosol in the European background

To constrain the relatively uncertain anthropogenic impact on the organic aerosol load, radiocarbon analyses were performed on aerosol samples, collected year-round, at six non-urban sites including a maritime background and three remote mountain stations, lying on a west-east transect over Western Europe. From a crude three component model supported by TOC and levoglucosan filter data, the fossil fuel, biomass burning and biogenic TOC fraction are estimated, showing at all stations year-round, a relatively constant fossil fuel fraction of around  (26 ± 6)%  , a dominant biogenic contribution of on average  (73 ± 7)%  in summer and the continental as well as the maritime background TOC to be only about 50% biogenic. Assuming biomass burning as completely anthropogenic, the carbonaceous aerosol concentration at the mountain sites was found to have increased by a factor of up to  (1.4 ± 0.2)  in summer and up to  (2.5 ± 1.0)  in winter. This figure is significantly lower, however, than the respective TOC change since pre-industrial times seen in an Alpine ice core. Reconciling both observations would require an increase, since pre-industrial times, of the background biogenic aerosol load, which is estimated at a factor of 1.3–1.7.     

Deglaciation of the Bara Basin near Malmö, Sweden

Results obtained by mapping and special varved clay investigation show that the so-called Northeastern ice advance (13,500 B.P.) and the Low Baltic readvance (13,000–13,200 B.P.) are separated by a significant deglaciation phase, for which we propose 'Lockarp Interstadial' (13,200-13,500 B.P.) as a time-stratigraphic term to be used in the type area of southwestern Scania.     

巴基斯坦橄榄石宝石学及矿物谱学特征研究

采用常规宝石学仪器并结合电子探针、激光剥蚀电感耦合等离子体质谱仪、(显微)红外光谱仪、紫外-可见吸收光谱以及拉曼光谱仪等测试方法,对巴基斯坦橄榄石进行了常规宝石学、化学成分和谱学特征等研究,并探讨了其产地鉴别方法和依据。结果表明,巴基斯坦橄榄石含有针状"硼镁铁矿-硼铁矿"、点状磁铁矿等特征矿物包裹体组合;与美国、中国、埃塞俄比亚、越南、马达加斯加等地所产的橄榄石相比,巴基斯坦橄榄石的微量化学元素组成相对富Li、B、Sc,贫Zn、Cu,同时V/Sc值偏低;巴基斯坦橄榄石红外吸收光谱中普遍存在的3 580 cm~(-1)附近吸收谱带与[Si]=(4H)~X_(Si)替代机制有关,指示其晶体中含有一定量的结构水;紫外-可见吸收光谱中的380、450、490、635 nm附近强吸收峰分别与O~(2-)→Fe~(3+)电荷转移带,Fe~(3+)的~6A_1→~4A_1+~4E(~4G)电子跃迁和Fe~(2+)的~5T_(2g)→~3T_(2g)、~5T_(2g)→~3T_(1g)电子跃迁有关。综合分析认为,包裹体、微量化学成分和结构水致红外吸收谱带特征组合可视为巴基斯坦橄榄石的产地鉴别依据。