共和盆地西缘柔起岗地区变质岩系锆石U-Pb年龄——原岩最老沉积时代及物源研究

共和盆地西缘原划古元古代金水口岩群中发育一套低级变质的灰色绢云石英片岩、绢云石英岩及黑云石英片岩组合,该套变质岩系原岩沉积时代及变质基底构造属性存在争议。本文对采自青海省兴海县柔起岗地区的两件片岩样品开展了系统的岩石学及LA-ICP-MS锆石U-Pb年代学研究,对其原岩沉积时代、沉积物源及基底构造亲缘性进行了探讨。结果表明,该套片岩两件样品的碎屑锆石U-Pb年龄谱可明显分为新元古代和古元古代两个主年龄谱以及中元古代的两个次年龄谱,新元古代主年龄谱分别为688~908 Ma和711~841 Ma,峰值年龄为788 Ma和780 Ma,古元古代主年龄谱分别为1871~2174 Ma和1832~2194 Ma,峰值年龄为2140 Ma和2072 Ma,中元古代两个次年龄谱分别为1520~1638 Ma和1271~1276 Ma,峰值年龄为1635 Ma和1275 Ma。片岩最小碎屑锆石年龄值688 Ma限定了其原岩的最老沉积时代。塔洞片岩碎屑锆石U-Pb年龄谱特征表明其碎屑物质来源较为复杂,物源主体来自周邻造山带的西秦岭、东昆仑和柴达木盆地北缘构造带的前寒武纪块体,扬子板块对其沉积物源亦有部分贡献,而华北板块没有对其提供沉积物源。更为重要的是,该套片岩锆石U-Pb年龄谱突出显示新元古代早期的构造-岩浆-热事件年龄信息,而没有华北板块典型的1850Ma和2500Ma左右的特征,结合区域资料认为西秦岭源区基底与东昆仑地块、柴达木盆地北缘、祁连地块等一样表现出扬子板块的构造亲缘性,源区基底固结时代为新元古代早期。

施肥和激素处理对草果结实影响

为了在既定的种植条件下,探讨草果盛花期施用复合肥、磷肥以及激素处理对草果(Amomum tsao-ko Crevost et Lemaire)结实率和果实单粒重的影响的最佳处理方式,以旱冬瓜(Alnus nepalensis D.Don)人工林下种植5年生草果为研究对象,于2009年5月进行多因素混合水平正交施肥及激素处理试验,辅助措施为人工授粉。于草果收获期计算不同施肥和激素处理方式下草果结实率及果实单粒重。结果表明,每蓬施用0.4 kg磷肥,0.5 kg复合肥,100 mg/L GA3处理后果实单粒重平均值达到20.55 g,比对照处理增长65.4%;结实率达到31.25%,比对照处理增长193.97%。因此,在既定种植条件和种植模式下,通过正交试验得出的施肥及激素处理方式可以显著提高草果结实量,为草果丰产提供了技术支持。

川陕丁家林金矿区探矿权的评估

为准确、客观估价丁家林金矿区探矿权价值,根据矿区地质报告中提交的储量级别、矿体控制程度和工程质量,确定了基础和可采储量、生产规模、矿山服务年限、贴现率、有关实物工作量等6项参数。综合运用贴现现金流量和重置成本法对探矿权进行评估,对达到详查程度的基础储量采用贴现现金流量法,控制程度低的资源量采用重置成本法,二者之和综合反映探矿权的价值。此方法适用于地质工作程度不均衡矿区的探矿权评估,贴现现金流量法要充分考虑储量的可信度和获利临界品位,重置成本法关键是准确确定有关的实物工作量。

Survey on the Diversity of Afforestation Plants in Xi'an City

Through investigating plants applied in the main streets and public greenbelts,the first-hand information about afforestation plants in Xi'an City was obtained for the first time.The results showed that,there are 136 species of plants in total belong to 102 genera,and 53 families,among which 122 species are woody plants belong to 89 genera and 44 families,i.e.89.71% of the total afforestation plants;14 species are herbaceous plants belong to 13 genera and 9 families,i.e.10.29% of the total;and there are 3 species of liana that belong to 3 genera and 2 families in woody plants with a ratio of 2.21%.The analysis showed that the landscape monotonicity was caused by the simplification of plant disposition pattern,as well as uneven quantity and frequency of applied afforestation plants.From the perspective of plant diversity,the proportion of herbaceous plants was too small;native plants were used widely which basically demonstrated the characteristics of local landscape,and most of exotic plants had obvious pantropic features which grew well in Xi'an City.This paper also analyzed problems in the present greening situation and put forward several suggestions for future tasks.

水泥稳定就地冷再生基层施工质量控制

文章对水泥稳定就地冷再生基层施工质量控制谈一些体会。