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71.
Joshua D. Cocker 《Australian Journal of Earth Sciences》2013,60(1-2):139-158
Biotite igneous ages and well‐defined isochron ages of plutons from the composite Blue Tier Batholith and the Coles Bay area in northeastern Tasmania range from 395 to 370 Ma. The older limit of this range, for the George River granodiorite, is considerably older than any age previously recorded for NE Tasmania. The ages of the youngest plutons (Mt Paris and Anchor granites), which host cassiterite ores, record pervasive hydrothermal alteration events. The initial 87Sr/80Sr ratios of the granitoids range from 0.7061 to 0.7136 and suggest different protolith compositions, consistent with mineralogical and geochemical characteristics of each pluton. The S‐type garnetbiotite granites (Ansons Bay and Booby alia granites) have initial ratios greater than 0.7119, indicative of enriched, high Rb/Sr ratio, crustal source‐rocks of Proterozoic age (1700–800 Ma). The S‐type biotite granites (Poimena and Pearson granites) have relatively high initial 87Sr/86Sr ratios (0.7070, 0.7105) but overlap with those of the I‐type granodiorites (George River, Scamander Tier, Pyengana and Coles Bay granodiorites) which are in the range of 0.7061 to 0.7073. The initial ratios of the enriched altered plutons are poorly constrained, and on both hand‐specimen and thin‐section scales, reveal open‐system Sr isotopic patterns. Isochron ages for the arenite‐lutite and lutite sedimentary associations of the Mathinna Beds, which are intruded by the granitoids, reflect an approach to Sr isotopic equilibrium during regional metamorphism. The metamorphic age (401 ± 7 Ma) of the early Pragian arenite‐lutite association indicates a relatively small time interval between deposition, regional metamorphism and granitoid intrusion. The isotopic age for the lutite sedimentary association (423 ± 22 Ma) is tentatively correlated with a Benambran‐age burial metamorphic event that has not previously been recorded in Tasmania. 相似文献
72.
Advances in quality, acquisition and processing of high-resolution digital topography over the past decade have enabled geomorphologists to interpret topography in terms of tectonic processes in a quantitative and more objective way. This study defines the tectonic impact of the North Anatolian fault system (NAFS) on the evaluation and activity of the Bolu pull-apart basin using morphometric indices based on topographic maps. In this study, three different indices including valley floor width to height ratio (Vf), asymmetry factor (Af), and Stream Length Gradient Index (SL) are applied to the tectonic basin area. To detect the deviation from spatial randomness of applied indices, the weighted correlation coefficient Moran’s I is used, and results are interpreted at 99% confidence interval. According to the results, the tectonic impact of NAFS on the northern and western sides of the basin distinctly differs from one another. Clustered distribution of Vf and Af values on the southern side of the basin margin reveals that this side of the basin margin is tectonically more deformed compared with the northern side. The applied methodology reveals that the spatial analysis of the morphometric indices proved to be the effective tool in analyzing tectonic influence of the fault system on the opposite side of the basin margins. 相似文献
73.
74.
In the paper the first attempt at the definition of a model to assess the impact of a range of different volcanic hazards on the building structures is presented. This theoretical approach has been achieved within the activities of the EXPLORIS Project supported by the EU. A time history for Sub-Plinian I eruptive scenario of the Vesuvius is assumed by taking advantage of interpretation of historical reports of volcanic crises of the past [Carafa, G. 1632. In opusculum de novissima Vesuvij conflagratione, epistola isagogica, 2a ed. Napoli, Naples; Mascolo, G.B., 1634. De incendio Vesuvii excitato xvij. Kal. Ianuar. anno trigesimo primo sæculi Decimiseptimi libri X. Cum Chronologia superiorum incendiorum; & Ephemeride ultimi. Napoli; Varrone, S., 1634. Vesuviani incendii historiae libri tres. Napoli], numerical simulations [Neri, A., Esposti Ongaro, T., Macedonio, G., Gidaspow, D., 2003. Multiparticle simulation of collapsing volcanic columns and pyroclastic flows. J. Geophys. Res. Lett. 108, 2202. doi:10.1029/2001 JB000508; Macedonio, G., Costa, A., Longo, A., 2005. HAZMAP: a computer model for volcanic ash fallout and assessment of subsequent hazard. Comput. Geosci. 31,837–845; Costa, A., Macedonio, G., Folch, A., 2006. A three-dimensional Eulerian model for transport and deposition of volcanic ashes. Earth Planet. Sci. Lett. 241,634–647] and experts' elicitations [Aspinall, W.P., 2006. Structured elicitation of expert judgment for probabilistic hazard and risk assessment in volcanic eruptions. In: Mader, H.M. Coles, S.G. Connor, C.B. Connor, L.J. (Eds), Statistics in Volcanology. Geological Society of London on behalf of IAVCEI, pp.15–30; Woo, G., 1999. The Mathematics of Natural Catastrophes. Imperial College Press, London] from which the impact on the building structures is derived. This is achieved by an original definition of vulnerability functions for multi-hazard input and a dynamic cumulative damage model. Factors affecting the variability of the final scenario are highlighted. The results show the high sensitivity of hazard combinations in time and space distribution and address how to mitigate building vulnerability to subsequent eruptive phenomena [Baxter, P., Spence, R., Zuccaro, G., 2008-this issue. Risk mitigation and emergency measures at Vesuvius]. 相似文献
75.
分析了文安Ms5.1级地震前后埕古Ⅰ井的水位异常变化,探讨了异常机理,认为文安地震前埕古Ⅰ井水位存在前兆异常,震后的几次水位变化则可能与羊二庄断层蠕动有关。 相似文献
76.
基于Moran统计量的空间自相关理论发展和方法改进 总被引:35,自引:2,他引:33
本文旨在发展基于Moran指数的空间自相关分析理论和方法。首先,利用线性代数知识对基于Moran统计量的空间自相关过程的数学表示进行规范化整理;其次,基于变换中的不变性思想给出Moran指数的理论解释;第三,对空间权重矩阵的数理性质、建设方法和应用范围提出新的见解。总结并发展了Moran指数的三种计算方法——三步求值法、矩阵标度法和回归分析法,将空间权重矩阵划分为四种基本类型——局域关联型、准局域关联型、准长程关联型和长程关联型。以河南省鹤壁市乡镇体系为实证对象,以本文改进的理论和方法为依据,提供了一个空间自相关分析的简明案例。 相似文献
77.
凡纳对虾引进亲本及其子代RFLP分析 总被引:8,自引:0,他引:8
运用 PCR-RFLP 技术分析凡纳对虾两个引进亲本群体及其各自子一代的遗传变异情况。用一对引物对这四个群体进行 mt DNA-细胞色素氧化酶I部分片段的 PCR 扩增,扩增结果为一条约 1.25 kb的条带。用 19种限制性内切酶对该扩增条带进行酶切分析,其中 Hinf I, Sty I, Taq I 这 种酶有酶切位点。用这3种 3酶进行限制性片段长度多态性 ( RFLP )分析,共获得 种限制性类型 基因型 。而且内切酶 2 ( ) Sty I在两个不同的引进亲本群体及其各自的子一代的扩增产物的酶切中,表现出明显的差异。 相似文献
78.
Tetraploid induction was carried out by inhibiting mitosis I in fertilized eggs ofChlamys farreri. Mitosis I was blocked with cold shock (5–7°C), Cytochalasin B (0.75 mg/L) and 6-dimethylaminopurine (6-DMAP) (60–75 mg/L)
when 60% fertilized eggs released polar body II at 20°C. At 4-cells embryo stage, the ploidy was determined by counting chromosome
number. In control groups, most embryos were diploids (72.22%) and aneuploids (24.78%). In Cytochalasin B, cold shock and
6-DMAP treated groups, tetraploids were respectively 10.51%, 4.08%, and 13.34%; aneuploids were 43.10%, 35.93% and 29.16%,
and triploids were 7.84%, 8.52% and 18.33%. At D-larva stage, ploidy was determined by flow cytometry (FCM). The ploidy analysis
of day 2 larvae showed diploids in control group and also in three treated groups. Juvenile scallops (0.2–0.3cm) which were
harvested in two control groups and two CB treated groups were all diploids through checking ploidy individually by FCM.
Contribution No. 3648 from the Institute of Oceanology, Chinese Academy of Sciences.
Contribution No. 238 from the Experimental Marine Biology Laboratory, Chinese Academy of Sciences.
Project funded by grant (No. 819-01-07) from the Chinese Science and Technology Ministry and also by “Hundred Talents Plan”
grant from the Chinese Academy of Sciences. 相似文献
79.
空间拓扑关系是GIS中空间查询和分析的基础。针对当前空间拓扑关系模型在表达较复杂对象间拓扑关系存在局限性的突出问题,以线对象为实例,根据点集拓扑理论,重新定义和区分线对象的复杂性;以9I模型为基础,提出一种适合二维复杂线对象的拓扑关系的线性序列描述模型,将复杂线-线的拓扑关系表示成基本拓扑关系的组合。分析不同情形下线之间拓扑关系不同的计算方法。为实现复杂线-线拓扑关系的计算,提高扫描线算法的效率,探讨包络矩形粗滤、线节点重合或共线的斜率坐标判断法等改进方法,提出判断线-线是否相交的矢量叉乘法,具有快速高效的特点。最后,通过实验系统导入线坐标串,进行图形绘制、拓扑关系计算并输出结果,从而验证该模型和算法的可行性。 相似文献
80.