西天山北部地区成矿规律初探

西天山北部地区可分为7个成矿带:阿拉套钨、锡、铜、铁、金成矿带;温泉—别珍套铜、铌钽成矿带;汗吉尕铅锌成矿带;赛里木铜多金属成矿带;科古琴铜多金属成矿带;博罗霍洛金成矿带;精河南阿勒坦金、锑成矿带。区域矿床成矿物质来源的复杂性和多源性以及区域成矿演化的控制,常常表现为矿床的共生叠加性和矿床分布的不均匀性。     

浙江江山灯影组碳、氧同位素特征

通过测试分析了浙江江山灯影组碳酸盐岩的碳、氧同位素特征。结果显示δ^13C值在-2．11‰～2．71‰之间，底、顶部表现为负异常，主体部分比较平稳，变化频率不大。呈微弱的降低趋势；δ^18O值在-3．52‰～-8．76‰之间变化，整体比较平稳，从底到顶呈略降低的变化趋势。浙江江山碳、氧同位素的特征与国内外同期地层非常相似，具有全球可对比性，反映浙江江山地区在灯影初期海平面短暂下降，随后海洋环境相对稳定，直到灯影末期，与全球古环境发生强烈变化一样，本区海洋环境也发生了强烈变化。     

浙江浦江晚中生代埃达克质火山岩的成因

浙江浦江地区白垩纪劳村组存在一套独特的中酸性火山岩,其主量元素表现出富 Al_2O_3(>16%)和 Na_2O(4.01%～4.52%),高 Na_2O/K_2O(1.94～5.51,平均2.89),高 Sr(583～643μg/g),贫 Y(11.4～13.2μg/g)和 HREE(如 Yb=1.16～1.26μg/g),以及低(~(87)Sr/~(86)Sr)_i(0.7041～0.7043)和高ε_(Nd)(t)(0.3～2.3)。这些火山岩在元素-同位素组成上明显不同于浦江地区或区域上的晚中生代中酸性火山岩,而与现代俯冲带产出的埃达克岩类似。由于这些岩石相对于晚中生代的基性岩浆具有更低的(~(87)Sr/~(86)Sr)_i 比值,因此难以通过玄武岩浆的分离结晶或同化混染作用来解释,最有可能是地壳部分熔融的产物,在构造背景方面,目前还没有确切的证据说明区域存在晚中生代洋壳的俯冲作用,我们倾向于认为劳村组埃达克质火山岩可能为新增生玄武质地壳部分熔融的结果,其形成与区域上中生代地壳增生作用有直接的动力学联系。     

浙江及邻区尾波Q值研究

基于单次散射(Aki)模型,利用2000年至今浙江及安徽台网记录的37次ML3.0以上地震的数字地震波资料,计算了浙江及邻近省区平均尾波Q值,并拟合了Q值对频率的依赖关系数据。结果为:Q(f)=212±33.5f0.62±0.11,与国内其它区域相比,本区域为Q值高值、对频率低依赖性区域。认为本研究区内构造活动弱,地震活动水平低。本文就Q值对频率、尾波窗长等的依赖性特征及影响Q值计算的噪声水平、滤波器、数据采样等因素进行了深入分析。     

长岭山北麓断裂上新发现的地震地表破裂带

通过野外地震地质调查,在甘肃省古浪县、景泰县交界处的长岭山地区新发现了丰富的线状分布的地震地表破裂现象,表现为基岩崩塌、黄土滑坡、地震裂缝、地震土林、地震沟槽、陷落坑以及断层陡坎等,局部可见残留的破裂滑动自由面。其分布严格受长岭山北麓活动断裂控制。通过地震地表破裂带本身的特征分析、年代学分析、地表破裂带长度与震级的拟合关系以及结合区域活动断裂资料研究,认为该地震地表破裂带可能为1927年古浪8.0级地震的产物。     

查表法设计华北地区最大震级时间序列模糊预测系统

本文介绍了查表法设计模糊系统(FSLE)的方法与原理,然后基于该方法建立了华北地区及主要地震带最大震级时间序列的预测模型,并进行了预测内符检验。分析认为,该方法的建模与预测精度较高,模型外推泛化能力较强,原理简单直观,计算结果稳健。因此,FSLE方法可作为地震趋势建模与预测分析工作中的一种有效工具。     

下扬子东南缘北段加里东期构造形迹新资料

皖浙交界的宁国、于潜一带,上奥陶统和下志留统厚度巨大且具有浊流沉积的特征,导致长期以来对这一地区加里东期大地构造背景的不同认识.通过1:25万区域地质填图,在震旦纪-下古生代地层中发现大量加里东期构造变形形迹和数处不整合接触关系,表明本区加里东运动强烈,华南地区广泛发育的加里东运动已经强烈地影响到扬子板块的南缘.这些发现为研究本区加里东期的大地构造环境和变形特点、扬子板块与华南板块的相互作用提供了新资料.     

A high-resolution reconstruction of Storglaciären mass balance back to 1780/81 using tree-ring data and circulation indices

Storglaciären in northernmost Sweden has the world's longest ongoing continuous mass-balance record, starting in 1946. To extend this mass-balance record, we have reconstructed summer (b_S) and winter (b_W) mass balances separately back to the mass balance year 1780/81 with annual resolution. We used tree-ring data for b_S and a set of circulation indices, based on the sea-level pressure, for b_W. Both proxies have correlation coefficients with respective mass balance components of ca. 0.7. The reconstructed net balance (b_N) of Storglaciären was well correlated to the observations during 1946-1980 (r = 0.8, p < 0.05). Our reconstruction agrees well with previously obtained results of northern Sweden glacier variability, where the predominantly positive b_N years between 1890 and 1910 correspond to the well documented post-Little Ice Age advance of Storglaciären. Furthermore, the results suggest that b_S, as a function of summer temperatures, is more important than b_W in determining the b_N, which is contrary to glaciers in the maritime parts of western Scandinavia. In general, b_N has been negative over the last 220 yr, suggesting a predomination of continental conditions over northern Sweden. However, the influence of b_W increased in the late twentieth century, indicating a shift to a more oceanic climate regime.     

Enter the working forest: Discourse analysis in the Northern Forest

In 1988, four states in the northeastern USA commissioned a study to address land use changes in the Northern Forest, 26 million acres of temperate and boreal forest extending from Maine to eastern New York State. Against a backdrop of economic destabilization and concerns regarding social and ecological implications of a real estate boom, the sustained deliberative dialogue catalyzed by this study has come to rely heavily on the ambiguous concept of “working forest.” To clarify political and environmental dynamics in the region, we analyzed how people respond to and seek to capitalize on the interpretive flexibility of the term working forest. We combine an analysis of socio-political discourses of working forest based on a structured literature review with an assessment of local peoples’ definitions of working forest based on a survey conducted in a pair of contrasting New York State communities. The first study site represents an amenity-oriented community (i.e. a place where the forest supports a service economy including recreation and tourism) and the other study site represents a timber-dependent community. By linking data from community-level analysis to data derived from a general analysis of forest politics, we seek to develop a more robust perspective. By comparing discourses across differently structured communities, we investigate how local forest politics are mediated by local economic development processes. Our study empirically illustrates contested and geographically uneven processes of social construction of environment and rural development in a region confronting pressures of globalization. Results indicate that timber harvesting is a heavily privileged management objective, as a logic of ‘the forest that pays is the forest that stays’ dominates. Environmental politics in the region, and perhaps more generally, increasingly conforms to a form of pragmatism in which economic opportunities structure conservation planning and investment.     

土壤—农产品系统中重金属含量关系的影响因素分析

针对浙江省主要粮食、油料大宗作物以及蔬菜、茶叶等各类典型经济作物,选择典型种植区开展了农产品及根系土壤调查,根系土壤样测定了土壤有机质、酸碱度及十多种重金属元素含量,农产品样测定了十多种重金属元素含量。采用分类统计、相关分析、含量分布散点图等方法,研究了农产品与土壤中重金属含量关系。结果表明,作物种类是决定农产品重金属含量的最主要因素;农产品与土壤中重金属含量总体上具有共消长的趋势;土壤有机质、pH值是影响作物对土壤重金属吸收累积的重要环境因素;作物样品采集、加工和分析过程中沾污问题可能会对土壤-农产品重金属含量的相关性产生较大影响。