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含矿与无矿侵入体的区分是阐明岩浆型矿床成因的基础,也是深部找矿预测的依据。本文选择四川米易青皮村岩体为例,通过岩相学及矿物成分剖面和定量化结构分析,试图阐明无矿岩浆侵入体的固结过程,并与攀枝花含矿岩体对比,进一步揭示含矿与无矿侵入体形成过程的区别。岩相学分析表明,青皮村岩体中粒辉长岩的造岩矿物可以划分为四个世代：①粗粒斜长石→②中粒斜长石+单斜辉石→③黑云母+铁钛氧化物→④伟晶状斜长石,展示了封闭系统的固结过程。加上粗晶辉长岩脉的矿物组合钠长石+单斜辉石+角闪石+磷灰石,可以将青皮村岩体的组成矿物划分为5个世代,进而划分成四个晶体群：通道晶体群、岩浆房晶体群、基质晶体群和流体晶体群。晶体成分剖面分析表明,通道晶和岩浆房晶显示正环带,具有封闭系统降温结晶的特点,其中通道晶的生长伴随着减压作用;基质晶初始为正环带,末期显示反环带,反映了残余流体的聚集与逃逸;而流体晶体群的产出则反映了超临界流体的相分离和排气作用。定量化结构分析揭示了岩浆固结晚期的粗化过程,是封闭岩浆系统固结过程的重要证据,与岩相学和晶体成分剖面分析结果一致。此外,青皮村岩体中Fe Ti氧化物含量甚低,其体积分数仅为4%,暗示它们不可能聚集成矿。与攀枝花岩体相比,青皮村岩体固结过程中缺失先存晶体的溶蚀结构,后者被认为是高温含矿流体输入的结果。据此,本文提出,外来含矿流体(透岩浆流体)输入与否决定了镁铁质岩浆侵入体的产矿能力;进而认为,是流体输入导致了岩浆分异,而不是岩浆分异产生了含矿流体。 相似文献
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湖泊沉积中的10Be含量变化——有助于识别第四纪古冰川的有无 总被引：1，自引：1，他引：0
20世纪50-70年代核试验产生的137Cs尘埃,在现代冰川和非冰川湖泊沉积剖面中的深度分布存在明显差异.同理,大气宇宙射线成因的长半衰期10Be尘埃,在第四纪冰川和非冰川湖泊沉积剖面中的深度分布也应存在差异.第四纪冰川湖泊,冰期时流域内冰雪和10Be的累积量大于消融量,间冰期时冰雪和10Be的消融量大于累积量.因此,冰川湖泊冰期的10Be入湖通量小于间冰期.湖泊沉积剖面10Be浓度的波动,很可能表征流域内冰雪消融与累积的变化.非冰川湖泊,不存在冰川的累积与消融对10Be入湖通量的影响.开展第四纪冰川与非冰川湖泊沉积10Be含量变化的对比研究,有可能为破译中国东部中低山区古冰川和青藏高原大冰盖的世纪之争提供新的证据. 相似文献
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利用HYPOMAT精定位方法,对各区域地震台网地震定位精度进行分析,主要对各地震台网观测报告中定位精度为Ⅱ类、Ⅲ类地震进行处理,找出影响地震定位精度的因素,提高定位精度,从而提高地震目录质量. 相似文献
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株洲市基于CGCS2000的城市控制网升级改造,获取了株洲市2000国家大地坐标系的大地基准和原有城市控制点及升级改造后控制点的2000国家大地坐标,并通过了检测验收;改造升级了的株洲城市控制网,更新了株洲市控制网的1954坐标,建立了与2000国家大地坐标系、1980坐标的转换关系,实现了基于CZTCORS网络RTK技术的似大地水准面成果的应用. 相似文献
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Antonella Diana 《Singapore journal of tropical geography》2013,34(1):25-39
This paper discusses the governing of subjects and objects' mobility in the context of trans‐border rice and corn trade on the China‐Laos frontier. It traces the attempts by a group of ethnic Tai Lue traders from China to assert themselves as ‘flexible subjects’ and economically triumphant actors on the Upper Mekong market in the era of economic regionalization. It illustrates how, between 2005 and mid‐2006, the traders' economic success relied on a variety of ‘border strategies’. ‘Border strategies’ include a gender‐balanced organization of trade, the instrumental deployment of trans‐border ethnicity, the appropriation of a Han style of business, the opportunistic reliance on the Chinese administration's ‘regime of graduated mobility’, and the enactment of a ‘war‐machine’ against Lao state agents. Yet, in late 2006, a new wave of state authoritarianism, enmeshed in corporate accumulation processes, inhibited the traders' success. The paper suggests that, unlike what some defenders of globalization and transnational theories maintain, in the age of economic regionalization, the alleged flexibility and increased mobility of subjects and objects across the borders of the Greater Mekong Subregion remain conditional on an unpredictable mechanism of loosening and tightening. This is part of a long‐applied governing pattern of ‘experimentation under hierarchy’ on the Sino‐Lao frontier. 相似文献
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The shared Torres Strait rock lobster (Panulirus ornatus) fishery provides important income for commercial and traditional fishers in Australia and Papua New Guinea. The lobster stock is first fished in Torres Strait by divers from both countries and then becomes vulnerable to Australian prawn trawlers, followed by Papua New Guinea trawlers during its annual breeding migration. Lobster catch sharing arrangements are governed by the Torres Strait Treaty ratified in 1985, but the sequential trawling of breeding lobsters has been controlled by bilateral agreements. A trawl ban was implemented in 1984 in both countries to conserve the breeding stock, but some trawling has been conducted in the Gulf of Papua since then and there is renewed interest in Papua New Guinea to resume trawling. To evaluate the impact of trawling migratory breeding lobsters on the lobster fishery, a model that combines a cohort depletion model with a stock recruitment relationship was developed in this study. The model showed that when the fishery is fully or over‐exploited by the dive fishery, trawling breeding lobsters would reduce both the spawning stock and the total catch of the fishery. The reduction in catch would increase with increasing fishing mortality. If trawling occurred on the Papua New Guinea side only, a redistribution of catch between Australia and Papua New Guinea would result in a small gain in catch for Papua New Guinea at the expense of the Australian dive fishery. But when fishing mortality reaches a certain level, any trawling in any country will incur catch loss to both countries. For the long‐term sustainability and maximum production of the fishery, regulations should be implemented in both countries under a co‐management scheme of a shared fish stock. 相似文献
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高斯平面上GPS工程网数据处理 总被引：2，自引：0，他引：2
结合工程控制网的特点，给出高斯平面上GPS工程网数据处理的数学模型，对提高网的精度进行探讨，编写的软件对某GPS工程网进行数据处理与分析。 相似文献
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Permeable coastal sediments act as a reactive node in the littoral zone,transforming nutrients via a wide range of biogeochemical reactions.Reaction rates are controlled by abiotic factors,e.g.,salinity,temperature or solute concentration.Here,a series of incubation experiments,using flow-through reactors,were conducted to simulate the biogeochemical cycling of nitrate (NO_3~?) and phosphorus (P) in permeable sediments under differentNO_3~?availability conditions (factor I) along a salinity gradient (admixture of river and seawater,factor II).In an oligotrophic scenario,i.e.,unamendedNO_3~?concentrations in both river and seawater,sediments acted as a permanent net source ofNO_3~?to the water column.The peak production rate occurred at an intermediate salinity(20).IncreasingNO_3~?availability in river water significantly enhanced netNO_3~?removal rates within the salinity range of 0 to 30,likely via the denitrification pathway based on the sediment microbiota composition.In this scenario,the most active removal was obtained at salinity of 10.When both river and seawater were spiked with NO_3~?,the highest removal rate switched to the highest salinity (36).It suggests the salinity preference of theNO_3~?removal pathway by local denitrifiers (e.g.,Bacillus and Paracoccus) and thatNO_3~?removal in coastal sediments can be significantly constrained by the dilution relatedNO_3~?availability.Compared with the obtained variation forNO_3~?reactions,permeable sediments acted as a sink of soluble reactive P in all treatments,regardless of salinity andNO_3~?input concentrations,indicating a possibility of P-deficiency for coastal water from the intensive cycling in permeable sediments.Furthermore,the net production of dissolved organic carbon (DOC) in all treatments was positively correlated with the measuredNO_3~?reaction rates,indicating that the DOC supply may not be the key factor forNO_3~?removal rates due to the consumption by intensive aerobic respiration.Considering the intensive production of recalcitrant carbon solutes,the active denitrification was assumed to be supported by sedimentary organic matter. 相似文献
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