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新疆阿舍勒铜锌矿区英云闪长岩年代学及地球化学 总被引:2,自引:0,他引:2
对新疆阿尔泰南缘阿舍勒铜矿区英云闪长岩进行了锆石LA-ICP-MS U-Pb年龄测定,获得了375.3±2.1Ma和386.2±3.8 Ma的加权平均年龄,表明英云闪长岩形成于早泥盆世晚期—中泥盆世早期。岩石地球化学分析结果表明:所有岩石具有高SiO2(74.72%~77.72%)和中等的Al2O3(12.06%~13.5%)含量,低的P2O5(<0.04%)和CaO(0.34%~1.65%)含量,且具有贫碱(K2O+Na2O=5.84%~6.59%)、富钠(Na2O/K2O=3.3~10.9)、过铝质(A/CNK=1.10~1.18)特点;富集LREE和Th、U、Pb元素,贫P、Sr、Nb、Ta、Ti元素,呈现明显的Eu负异常(δEu=0.47~0.81),属低钾过铝质岩石。综合阿尔泰造山带南缘的区域地质资料及英云闪长岩的地球化学特征,认为阿舍勒铜锌矿区英云闪长岩是早中泥盆世的活动大陆边缘环境陆壳岩石部分熔融的产物。 相似文献
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A bstract In the present study,the effect of one-generation divergent selection on the growth and survival of the bay scallop(Argopecten irradians concentricus)was examined to evaluate the effi cacy of a selection program currently being carried out in Beibu Bay in the South China Sea.A total of 146 adult scallops were randomly selected from the same cultured population of A.i.concentricus,and divided into two groups in shell length(anterior-posterior measurement): large(4.91–6.02 cm,n=74)and small(3.31–4.18 cm,n=72).At the same time,a control group was also randomly sampled(4.21–4.88 cm,n=80).Mass-spawned F 1 progenies from the three size groups were obtained and reared under identical conditions at all growth phases.The effects of two-way(or upward-downward)selection on fertilization rate,hatching rate,survival rate,daily growth in shell length and body weight were assessed in the three size groups.Results show that signifi cant differences(P0.01)were found in hatching rate,survival rate and daily growth of F 1 progenies,but not in fertilization rate(P0.05),among the three groups.The hatching rate,survival rate and daily growth of the progeny of large-sized parents were greater than those of the control group(P0.05),which in turn were larger than those of small-sized group(P0.05).Responses to selection by shell length and body weight were 0.32±0.04 cm and 2.18±0.05 g,respectively,for the upward selection,and-0.14±0.03 cm and-2.77±0.06 g,respectively,for the downward selection.The realized heritability estimates of shell length and body weight were 0.38±0.06 cm and 0.22±0.07 g for the upward selection,and 0.24±0.06 cm and 0.37±0.09 g for the downward selection,respectively.The change in growth by bidirectional selection suggests that high genetic variation may be present in the cultured bay scallop population in China. 相似文献
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黄河源区径流对气候变化的响应及敏感性分析 总被引:4,自引:1,他引:3
Response of the runoff in the headwater region of the Yellow River to climate change and its sensibility are analyzed based on the measured data at the four hydrological stations and ten weather stations during the period 1959–2008. The result indicates that change of temperature in the region has an obvious corresponding relationship with global warming and the changes of annual average temperature in each subregion in the region have been presenting a fluctuant and rising state in the past 50 years. However the change of precipitation is more intricate than the change of temperature in the region because of the influences of the different geographical positions and environments in various areas, and the change of annual precipitation in the main runoff-producing area has been presenting a fluctuant and decreasing state in the past 50 years. And there is a remarkable nonlinear correlativity between runoff and precipitation and temperature in the region. The runoff in the region has been decreasing continuously since 1990 because the precipitation in the main runoff-producing area obviously decreases and the annual average temperature continuously rises. As a whole, the runoff in each subregion of the headwater region of the Yellow River is quite sensitive to precipitation change, while the runoff in the subregion above Jimai is more sensitive to temperature change than that in the others in the region, correspondingly. 相似文献
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针对遥感影像数据海量的特点和对安全保密的应用需求,提出了一种面向内容的遥感影像多级安全授权方法。采用选择性的多机密区域多密级的遥感影像加密算法,在保持遥感影像格式和各项应用特性不变的基础上,分发给不同用户相同处理后的影像数据和不同权限的密钥,使不同用户通过各自密钥解密获取不同信息程度的影像数据。实验结果表明,该方法具有高机密性和高计算效率,能有效解决海量遥感影像数据的安全保密难题。 相似文献
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黔中隆起的形成时间及形成机制探讨 总被引:6,自引:0,他引:6
黔中隆起经历了水下和陆上两个发育阶段;都匀运动是这一发育转变的成因。问题的焦点是水下隆起的开始时间和都匀运动发生的具体时间。根据沉积相研究,受郁南运动控制,黔中隆起在下奥陶统桐梓组沉积期间已具雏形。对贵阳乌当发现的珊瑚化石Plasmoporella、Heliolites、Amsassia等重新厘定后认为黔中隆起大规模露出水面的时间为晚奥陶世五峰组沉积期结束之时,这也是都匀运动发生的时间。都匀运动本身,受到自南而北方向的滇桂—北越地块的挤压和南东—北西方向的加里东造山运动的挤压,因此在黔中及周缘地区形成了以黔中背斜、乌当—二比向斜为代表的东西向构造和以麻江背斜为代表的南北向构造并存的地质现象。 相似文献
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青甘宁三省区定点洪水调查方法研究 总被引:1,自引:1,他引:1
洪水调查资料是科学地认识洪水发生的自然规律,正确地进行洪水计算,分析地区水文特性,进行水利、水电和其他国民经济建设不可缺少的基本资料。原甘肃省水文总站1976年就创造性提出定点洪水调查并于实施,青海省、宁夏回族自治区水文部门也先后实施定点洪水调查工作。通过对三省区定点洪水调查原始资料搜集、整理汇总、合理性分析、成果汇编,建立了一整套科学、实用的洪水调查理论方法和质量控制体系;提出了系统、权威的三省区河段定点调查洪水资料汇编成果。结果表明:定点洪水调查为弥补西部干旱地区水文站网不足,发挥了不可替代的作用。在经济欠发达的西部省(区)收集水文资料,是一个很好的途径,具有投资小、收集资料面广、机动灵活性强等特点,具有广泛的推广价值;定点洪水调查能够获取中小河流河段年最大洪峰流量,并能形成一定的资料系列长度,为涉水工程设计、工程安全复核、防洪管理及工程调度提供基础依据,具有广泛的应用价值。 相似文献
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