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<正> 唐巴勒蛇绿岩是西准噶尔地区出露最好、层序保留最完整的蛇绿岩。本文在地质学、岩石学和地球化学等方面的研究基础上,对该蛇绿岩的成因、原始生成构造环境和构造演化等问题进行了探讨。 1.唐巴勒蛇绿岩的地质特征 该地区属于哈萨克斯坦板块的一部分。唐巴勒蛇绿岩出露于该地区的西南缘,其原始层序自下而上大致为:变质橄榄岩→堆积杂岩→辉绿杂岩及浅色杂岩→基性熔岩及放射虫硅质 相似文献
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德兴-黄山断裂带及其邻区的地质研究进展 总被引:3,自引:0,他引:3
德兴-黄山断裂带以往都被认为是由伏川蛇绿岩套、赣东北蛇绿岩带组成的中元新古代蛇绿混杂岩带,代表扬子板块与华夏板块拼贴的北西界缝合线。近年来的地质调查表明,扬子和华夏两板块拼贴带大致介于宜丰-景德镇断裂、萍乡-广丰-江山断裂带之间,是一个多期碰撞造山带,称江南复合混杂岩带,而德兴-黄山断裂带则不具板块边界性质,仅是该混杂岩带内的一条分隔次级构造单元的边界断裂,总体呈NNE向展布,包括赣东北蛇绿混杂岩和一系列NNE向韧性剪切带和脆性断裂。伏川蛇绿岩和赣东北蛇绿岩走向上无法连接,分别代表江南复合混杂岩带内不同拉分小洋盆的沉积-构造混杂产物。本文对断裂带及其邻区前震旦纪地层重新划分进行了论述。 相似文献
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目前,豆荚型铬铁矿床的研究仍然是各国地质学家最关注的问题之一。近十几年来的研究证明,豆荚状铬铁矿床有一定的共性:(1)矿床常赋存于堆积杂岩接触带之下的一定层位中;(2)矿体与纯橄岩+斜辉辉橄岩杂岩带有关;(3)矿石可划分为高铝和高铬型两类,并与特定的岩石组合有关;(4)矿体的分布与变形构造(线理、叶理)关系密切;(5)矿体产于高磁、高电、低重力异常区;(6)矿床产于扩张脊环境。鉴于上述特点,不同的学者提出了不同的成因观点:一种观点认为铬铁矿浆最早形成于堆积杂岩岩浆房底部,后与纯橄岩一起结晶,在自身重量的作用下“沉入”斜辉辉橄岩中(J.Dickey,1975);另一种观点认为矿体产于斜辉辉橄岩中的岩浆通道的“洞穴”中,经对流循环而成矿(B.L.Lago等,1982);其成岩成矿的微观机制是原始地幔岩的部分熔融作用,成矿物质铬尖晶石来源于单斜辉石等矿物的不一致熔融(王希斌等,1987)。 相似文献
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<正> 本文研究了赋存大多数金刚石矿化的前寒武纪沉积杂岩的成份和组构,其目的是为了评价前寒武纪沉积杂岩含金刚石的可能规模。根据对该杂岩组构特点的分析,可以把含金刚石的陆源沉积剖面划分为两个主要类型,这两种类型的形成与不同的构造运动环境有关,并且它们的稳定矿物组份的堆积条件不同。 相似文献
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利用电子鼻技术可对不同行业的工业废气污染源进行智能鉴别。采用主成分分析法(PCA)对20种不同企业排放的工业废气进行建模区分,并在主成分分析法的基础上,利用判别因子分析法(DFA)分别对5类不同行业的工业废气污染源建立了行业鉴别DFA模型。分析结果显示:主成分分析法可以对不同企业排放的工业废气实现很好的区分;鉴别模型可以实现不同行业排放的工业废气污染源的准确鉴别。研究表明电子鼻技术可以较好地区分不同企业排放废气的特征信号,从而实现对工业废气污染源的智能鉴别。 相似文献
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皖南江南隆起区出露的前寒武系变质杂岩研究的新资料,进一步揭示了岩石成因、时代、地球化学组成和地壳演化特征。重新厘定了上溪群为古元古代,由一套安山岩、英安岩、流纹岩及层凝灰岩经变质而成,它构成了江南-雪峰隆起高原科马提绿岩的一部分。地球化学组成具原始地幔特征。其上的新元古代蛇绿岩套,是由10亿年左右的一套橄榄-蛇纹岩、辉橄岩、辉长岩、堇青石斜长闪长岩、辉绿岩、细碧角斑岩、硅质-碧玉岩组成。其地球化学组成为亏损地幔,呈典型的活动大陆边缘的大洋盆生长层。不整合覆于老地层之上。上述两套岩层性质的确定.证明了元古宙上、下两套绿岩是组成华南基底的主要生长层。由地幔柱活动所引起的两次突变事件形成的火山物质组成了扬子地块的中下地壳。因此,地球系统的演化主要是由地球内部的物质交替所推动,它强烈的影响气圈、水圈、生物圈,也推动生物的前进演化。鉴于此,皖南元古宙绿岩的新资料,无疑是十分重要的,对正确认识华南的壳-幔演化有一定的参考价值。 相似文献
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累积影响评价:中国内地与香港的问题与实践探讨 总被引:10,自引:0,他引:10
将过去、现在和将来的其它活动包括在建议活动的评价范围 ,是累积影响评价区别于传统EIA的重要特征和关键环节 ,也是EIA进一步发展完善的重要趋势 .从法规要求、文本格式、时空范围、重点内容、减缓措施等方面 ,分析了内地和香港在环评实践过程中对累积影响的考虑状况及存在问题 .建议制定累积影响评价的技术方法导则 ,以法规的形式明确提出在项目、区域及策略环评中增加累积影响评价的内容 ,累积影响应在环评报告的摘要、目录及结论中专门列出 ,对累积影响时空范围的界定及重要性的判断应专门提供支持依据 ,评价的重点应较多地关注生态完整性、社会经济影响及全球性环境影响等 ,以更有效地预防累积环境影响问题 . 相似文献
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基于SD-CA-GIS的环境累积效应时空分析模型及应用 总被引:6,自引:1,他引:5
环境累积效应分析强调环境变化的时空放大作用,突出环境要素之间的时空交互作用,从而对环境分析方法的能力提出了挑战.因此,本文在对传统环境分析方法归纳、分析和总结的基础上,以地理信息系统(GIS)为基础平台,集成系统动力学(SD)和元胞自动机(CA)的优点,建立了能够分析时间累积、空间累积效应的SD-CA-GIS模型.以山西潞安矿区作为研究区域,在分析矿区社会、经济、工程和环境等因子之间时空交互作用的基础上,构建了SD-CA-GlS模型.考虑到矿区土地利用变化的特殊性,从影响矿区土地利用变化的驱动因子出发,预测和模拟了矿区2006-2030年土地利用变化的累积状况.结果发现,由于煤炭资源开采等人类干扰活动的影响,研究区在研究时段内,工矿用地、居民用地和交通用地呈现累积性增加,其它土地利用类型累积性减少.同时,由于不同阶段人类活动干扰的种类和强度变化,使得不同土地利用类型的空间扩展变化存在一定的差异.上述研究表明,该模型能够同时考虑时间累积效应和空间累积效应的动态变化,能为环境累积效应的分析和评价提供有效的帮助. 相似文献
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Ken’ichi Matsumoto Kaoru Tachiiri Michio Kawamiya 《Mitigation and Adaptation Strategies for Global Change》2018,23(1):1-26
Recent climate modeling studies have concluded that cumulative carbon emissions determine temperature increase, regardless of emission pathways. Accordingly, the optimal emission pathway can be determined from a socioeconomic standpoint. To access the path dependence of socioeconomic impacts for cumulative carbon emissions, we used a computable general equilibrium model to analyze impacts on major socioeconomic indicators on a global scale for 30–50 pathways with different emission reduction starting years, different subsequent emission pathways, and three different cumulative 2100 emission scenarios (emissions that meet the 2 °C target, the 2 °C target emissions plus 10 %, and emissions producing radiative forcing of 4.5 W/m2). The results show that even with identical cumulative emission figures, the resulting socioeconomic impacts vary by the pathway realized. For the United Nations 2 °C target, for example, (a) the 95 % confidence interval of cumulative global gross domestic product (GDP) is 1355–1363 trillion US dollars (2010–2100, discount rate = 5 %), (b) the cumulative GDP of pathways with later emission reduction starting years grows weaker (5 % significance level), and (c) emissions in 2100 have a moderate negative correlation with cumulative GDP. These results suggest that GDP loss is minimized with pathways with earlier emission reduction followed by more moderate reduction rates to achieve lower emission levels. Consequently, we suggest an early emission peak to meet the stringent target. In our model setting, it is desirable for emissions to peak by 2020 to reduce mitigation cost and by 2030 at the latest to meet the 2 °C target. 相似文献
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The hummingbird hawkmoth, Macroglossum stellatarum, learns colour fast and reliably. It has earlier been shown to spontaneously feed from odourless artificial flowers. Now, we have studied odour learning. The moths were trained to discriminate feeders of the same colour but marked with different odours. They did not learn to discriminate two natural flower odours when they were presented with the innately preferred colour blue, but they did learn this discrimination combined with yellow or green colours that are less attractive to the moth. The yellow colour could be trained to become as attractive as the innately preferred blue colour and the blue colour could be trained to become less attractive. This is the first proof of odour learning in a diurnal moth. The results show that M. stellatarum can use more than one modality in their foraging behaviour and that the system is plastic. By manipulating the preferences for the different colours, their influence on odour learning could be changed. 相似文献
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Accurate recognition requires that visual systems must be able to discriminate between target and distractor stimuli. Flowers are learned and recognised by bees using visual cues including colour and shape. We investigated whether bees were able to learn to discriminate between colours differently depending upon absolute or differential conditioning. For absolute conditioning bees were rewarded with sucrose solution for visits to target flowers. When distractor stimuli were subsequently presented, a high level of discrimination was observed if there was a perceptually large colour distance separating distractors and targets, but for a perceptually small colour distance the bees generalised and did not discriminate between stimuli. When provided with differential conditioning where both target and distractors were present, the bees learnt to discriminate stimuli separated by a perceptually small colour distance. This shows that for bees to learn fine colour discrimination tasks it is important to use differential conditioning. The findings are discussed within the context of the necessity for plants to produce distinctive flower colours. 相似文献
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沿长乐-南澳断裂带分布有非蛇绿岩型的镁铁、超镁铁质岩块;具中、新生代裂谷型岩浆组合;断裂两侧具有相似的变质岩基底及对应显著的地幔隆升地带。说明该断裂带为一条正在发育的中、新生代裂谷带。 相似文献