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91.
塔里木地台西南缘皮山县煌斑岩脉群为超钾系列的煌斑岩,侵位于元古宇角门片岩中。经~(40)Ar/~(39)Ar法测定,煌斑岩中金云母的等时线年龄为(231.7±0.3)Ma,全岩等时线年龄为(228.5±0.3)Ma。地球化学数据指示其源区为受俯冲 相似文献
92.
Wahizatul Afzan A Che Salmah M R 《湿地科学》2005,3(3):167-175
1INTRODUCTION Manyfactorshavebeenlinkedwithobserved patternsofodonatediversity.Eachhabitatisdifferent andpresentsitsownopportunitiesforexploitationby welladaptedspecies(Krebs,1989).Theyaresensi tiveresponderstonewlycreatedphysicalandtogether withphysiogra… 相似文献
93.
J.Langbein R.Borcherdt D.Dreger J.Hetcher J.L.Hardebeck M.Hellweg M.Johnston J.R.Murray R.Nadeau M.J.Rymer J.A.Treiman 申彤 《世界地震译丛》2005,(4):14-31
引言 2004年9月28日17时15分14秒(协调世界时)加州中部帕克菲尔德发生了一次 Mw6.0级地震。震中位于圣安德烈斯断层靠近戈尔德希尔附近的帕克菲尔德镇东南 11 km的地方(图1)。加州综合地震台网 (CISN)报告说,震源位于北纬35.819°,西经120.364°的8.8 km深的地下。根据余震的分布状况以及此次地震的地震图、应变变 相似文献
94.
Ferraro G Bernardini A David M Meyer-Roux S Muellenhoff O Perkovic M Tarchi D Topouzelis K 《Marine pollution bulletin》2007,54(4):403-422
Studies of operational pollution carried out by European commission - Joint Research Centre in the Mediterranean Sea for the years 1999-2004 are briefly introduced. The specific analysis of the Adriatic Sea for the same period demonstrates that this area has been characterized by a relevant number of illegal discharges from ships. After setting the historical background of the project AESOP (aerial and satellite surveillance of operational pollution in the Adriatic Sea), the content, partners and aim of the project are presented. Finally, the results of the first phase of the AESOP project are presented. The results seem very encouraging. For the first time in the Adriatic, real time detection of oil spills in satellite images and an immediate verification by the Coast Guard has been undertaken. An exploratory activity has also been carried out in collaboration with the University of Ljubljana to use automatic information system (AIS) to identify the ships detected in the satellite images. 相似文献
95.
青藏块体北缘跨断层测量资料宏观分析 总被引:1,自引:1,他引:1
本文在系统整理青藏块体北缘跨断层测量资料的基础上,进行了形变类型的划分,探讨了不同类型形变所反映的断层运动性能。 相似文献
96.
Geophysical studies point to a complex tectonic and geodynamic evolution of the Alboran Basin and Gulf of Cadiz.Tomographic images show strong seismic waves velocity contrasts in the upper mantle.The high velocity anomaly beneath the Alboran Sea recovered by a number of studies is now a well established feature.Several geodynamic reconstructions have been proposed also on the base of these images.We present and elaborate on results coming from a recent tomography study which concentrates on both the Alboran and the adjacent Atlantic region.These new results,while they confirm the existence of the fast anomaly below the Alboran region,also show interesting features of the lithosphere-asthenosphere system below the Atlantic.A high velocity body is imaged roughly below the Horseshoe Abyssal plain down to sub-lithospheric depths.This feature suggests either a possible initiation or relic subduction.Pronounced low velocity anomalies pervade the upper mantle below the Atlantic region and separate the lithospheres of the two regions.We also notice a strong change of the upper mantle velocity structure going from south to north across the Gorringe Bank.This variation in structure could be related to the different evolution in the opening of the central and northern Atlantic oceans. 相似文献
98.
温度和含水量是形成花岗质岩浆最重要的两个参数。在大多数硅质岩浆中,水的含量为2-4wt%。水的主要来源有二,其一是地壳内含水硅酸盐的脱水作用,并视脱水矿物为白云平、黑云母或角闪石,所产生熔体的初始温度相应依次升高,成分由过铝质到偏铝质变为偏铝质到过碱质,K/Na比值、^87Sr/^86Sr初始比值和δ^18O值则依次降低。水的另一主要来源是由俯冲洋壳及上地幔(以含水玄武岩和安山岩的形式)迁移到地壳中的挥发分,所产生花岗岩的地球化学性质将随地壳岩浆与地幔岩浆的相对重要性而变化。 相似文献
99.
Kirby MF Smith AJ Barry J Katsiadaki I Lyons B Scott AP 《Marine environmental research》2006,62(4):315-325
This study was conducted as an initial investigation of 'differential response' in one of the main sentinel organisms used for monitoring programmes in United Kingdom estuaries, the flounder Platichthys flesus. It has been hypothesised that monitoring using species with a wide geographical spread and limited migration, such as flounder, might result in the comparison of different genetic stocks and certainly of populations with differing early life stage contaminant exposure histories. Furthermore, it is probable that these pre-exposure and genetic differences could manifest themselves in an ability to respond differently to contaminant exposure, so-called 'differential response'. It is important that the extent and nature of this response is understood, if we want to be able to fully interpret the monitoring data from such programmes. During this study, flounder were collected from four separate sources; wild caught fish from the estuaries of the Rivers Alde, Mersey and Tyne, and farmed flounder from Port Erin Farm, Isle of Man. Under controlled laboratory conditions, groups of fish from each source were exposed to water-borne concentrations of the synthetic oestrogen ethynylestradiol (EE2) at a nominal concentration of 50 ng/l. Plasma was taken from each male fish after 6 and 10 days exposure and analysed for the presence of vitellogenin (VTG) using an ELISA technique. Significant levels of VTG induction were evident in fish from all sources after both 6 and 10 days exposure. Flounder from the Mersey were the only fish with significantly elevated initial background levels of VTG (day 0) and this appeared to be reflected in that these specimens showed the highest induction response after day 6. However, after day 10, fish from all other sites had a slightly higher mean VTG than those from the Mersey which showed significantly (p < 0.05) lower mean plasma VTG. It is suggested that other differential responses may have been masked by the use of a high dose of EE2 which produced maximum induction in nearly all fish. The findings of the study are discussed in terms of implications for further research into the differential response issue and how the initial plasma VTG figures contribute to a time-series from the Mersey, Tyne and Alde estuaries. 相似文献
100.
Mohammad Rasul Jan Mahmood A Khawaja Jasmin Sha Kashif Gul 《中国地球化学学报》2006,25(B08):182-182
Due to the persistent nature of DDT, a persistent organic pollutant and its adverse environmental and health impacts, the present study was undertaken to examine the residual DDT in and around DDT manufacturing factory in Amman Gharh, Nowshera, NWFP. The factory was established in 1963 and remained in operation till 1994. Composite samples of soil, sediments and water were collected in and around the factory area, nearby DDT stores, main factory drain leading to river and nearby villages. Standard procedures were used for the collection, transportation and storage of samples for analysis. Physical parameters for the collected water samples measured were temperature, pH and conductance. Extraction of each sample for DDT analyses was carried out in triplicates using soxhlet extraction apparatus. The extract was transferred to well washed, clean; dry glass vial, sealed and put in the refrigerator. Gas Chromatograph with electron capture detector and capillary column was used for analysis. DDT in the samples was identified on the basis of their retention time and quantified on the basis of peak areas. It is evident from the analytical data obtained in the present study that both water and soil in and around the factory area are still contaminated with DDT, despite the closure of the factory since the past few years. 相似文献