胶北南山口含榴辉石岩岩石学与锆石U-Pb定年的初步研究

胶北南山口镁铁-超镁铁质杂岩主要由含榴辉石岩和含榴基性麻粒岩所组成,且以不规则透镜体的形式赋存于太古宙英云闪长质片麻岩之中。岩相学观察、矿物相转变分析与矿物化学研究结果表明,胶北南山口含榴辉石岩不仅普遍发育近等温减压反应结构,即石榴石+富钙流体→单斜辉石+葡萄石+榍石±钠长石与石榴石+富钙流体+二氧化碳→角闪石+葡萄石±钠长石±方解石±榍石,指示其早期可能经历了高压麻粒岩相变质作用。而且,与南山口含榴基性麻粒岩类似,在晚期降温退变过程中,它们还经历了强烈的钙质交代作用,形成富钙矿物组合:富钙铝榴石的石榴石+次透辉石质单斜辉石+钙质角闪石+葡萄石+钠长石+方解石+榍石。SHRIMP锆石U-Pb定年结果表明,胶北南山口含榴辉石岩中的岩浆锆石记录了2900~2850Ma的207Pb/206Pb年龄,指示胶北地体在中太古代晚期存在一次重要的岩浆事件,而其变质锆石还记录了1950~1800Ma的207Pb/206Pb年龄,说明胶北南山口镁铁-超镁铁质杂岩曾卷入了胶北古元古代晚期地壳造山作用。结合研究区其它地质研究资料,本文推断胶北南山口镁铁-超镁铁质杂岩可能形成于古元古代,是华北克拉通胶-辽-吉带古元古代岩系的重要组成部分,并于1950~1800Ma期间,卷入了胶-辽-吉带古元古代造山作用,先后经历了高压麻粒岩相变质作用和晚期降温与钙质交代的联合退变质作用。     

榴辉岩的化学分类

以山东荣成地区的榴辉岩为例,把榴辉岩分为镁一榴辉岩、铁一榴辉岩和钙一榴辉岩三类。三类榴辉岩的岩石化学,主要造岩矿物成分都有明显差别,石榴石分别是镁铝榴石、铁铝榴石和钙铝榴石。绿辉石的硬玉分子也有不同。三类榴辉岩的化学成分限制是Mg-榴辉岩MgO>10%,石榴石以镁铝榴分子占优势,Fe-榴辉岩的MgO<10,石榴石以铁铝榴石分子占优势。Ca-榴辉岩CaO>19%,石榴石以钙铝榴石分子优势。     

冀东迁滦地区沉积变质型铁矿床变质作用程度：来自石榴子石的制约

石榴子石是冀东地区沉积变质铁矿中常见的变质矿物之一。本文采集迁安-滦县地区代表性铁矿中含有石榴子石的岩石样品,对其石榴子石进行电子探针和X-射线粉晶衍射分析,得出司马地区为角闪岩相,杏山-黄柏峪一带为角闪岩-麻粒岩相,水厂-大石河地区为麻粒岩相,这与前人对迁滦地区用主要矿物共生组合等来研究变质相的结论相一致;同时迁滦地区沉积变质铁矿中石榴子石的端元组分和晶胞参数a0随变质程度的增加呈规律性变化: 司马地区的铁铝榴石+钙铝榴石→杏山-黄柏峪一带的铁铝榴石→水厂-大石河一带铁铝榴石+镁铝榴石,其晶胞参数a0值逐渐减小。因此在沉积变质型铁矿床中,变质矿物石榴子石的化学成分及晶胞参数特征对不同地区的变质程度具有示踪意义。     

中国境内可能存在一条新的高压/超高压(?)变质带——青藏高原拉萨地体中发现榴辉岩带

新发现榴辉岩带位于拉萨北东方向,产在青藏高原拉萨地体中东部。观察到的榴辉岩带宽度约500~600m,呈近东西向延伸,已知规模10km以上。榴辉岩为常见的金红石榴辉岩、石英榴辉岩和多硅白云母榴辉岩。榴辉岩的单斜辉石中含硬玉分子变化较大,Jd=16%~44%,但均落于绿辉石成分区间;石榴子石中镁铝榴石(Pyrope)端元组分16%~33%,铁铝榴石(Alm)40%~54%,钙铝榴石(Gross)22%~31%。利用Grt-Omp-Phe和Grt-Omp矿物组合对变质温-压初步估算,获得金红石榴辉岩样品06Y-334的变质p、t分别为2.58GPa、635℃和2.67GPa、730℃,样品06Y-345的t主要在680~780℃区间,样品06Y-336的t主要在640~740℃区间,3个样品获得的结果相近。显微镜观察表明多硅白云母可能为折返阶段的退变质矿物而不属变质峰期的矿物,推测峰期的压力值有可能高于2.67GPa而进入柯石英稳定区间(p>2.8GPa)。石榴子石和绿辉石中出现的一些类似柯石英假象的石英包裹体与这一推断相吻合。以上初步研究结果表明,拉萨地体的榴辉岩带可能是中国境内又一条高压/超高压(?)变质带。     

河南窑场铁矿床成因矿物学研究及其地质意义

窑场铁矿床位于河南鲁山地区,大地构造位置属于华北陆块南缘,控矿地层为太华群铁山岭组,主要矿体共有两个,主要有辉石铁英岩和角闪石铁英岩组成,夹有少量的黑云角闪片岩、大理岩和花岗质混合岩,主要的矿石矿物为磁铁矿(30%～35%),少量赤铁矿(5%)和镜铁矿(3%)。脉石矿物有石英、角闪石、辉石、石榴子石等。围岩的组成包括黑云辉石岩、黑云角闪岩、黑云角闪片岩、黑云片岩、角闪黑云变粒岩、大理岩及少量的花岗质混合岩。矿石中的角闪石均属于镁角闪石,辉石有富铁透辉石、斜铁辉石,磁铁矿以纯磁铁矿为特征;围岩中的角闪石属于镁角闪石和纯镁闪石,辉石主要为透辉石,黑云母为镁质黑云母,伴有少量金云母,石榴子石以铁铝榴石为主,含有镁铝榴石、钙铝榴石分子。化学成分分析显示本区的变质相达角闪岩相,估算其变质的压力范围为0.36GPa～0.74GPa。与典型华北陆块前寒武纪铁矿床对比,窑场铁矿床的矿物组合、变质等级以及沉积相类型均与新太古代的条带状铁建造相似。磁铁矿高Ni、低Co的特点表明其成矿来源与深部物质有关。     

接触交代夕卡岩型矿床中石榴子石和辉石成分特点及其与矿化的关系

本文对中国十四个接触交代钙夕卡岩矿床和钙-镁夕卡岩矿床中的三百多个样品的石榴子石和辉石成分进行了电子探针分析。不同矿床类型的石榴子石和辉石成分代表着钙夕卡岩矿床的十个矿种(Fe、Fe-Cu、Pb-Zn、W、Sn、Sn-Mo-Bi-W、、W-Bi-Cu-Mo、Cu-Zn、Cu-Sn、W-Zn-Cu)和钙-镁夕卡岩矿床的三个矿种(Fe-Cu、Mo、Pb-Zn)。石榴子石和辉石成分变化范围大,大多数石榴子石是含锰铝榴石+铁铝榴石+镁铝榴石小于15％(摩尔百分数)的钙铝榴石-钙铁榴石固溶体;大多数辉石是含小于5％的锰钙辉石的透辉石-钙铁辉石固溶体。有些Pb-Zn钙-镁夕卡岩矿床中的辉石显示出Mn含量有所增加。只有Sn和W钙夕卡岩矿床及Pb-Zn钙-镁夕卡岩矿床含(Sps+Alm+Pyr)总量大于15％的石榴子石。石榴子石和辉石成分与夕卡岩矿床金属矿化类型之间有某些联系。     

大别山北部榴辉岩和英云闪长质片麻岩锆石U-Pb年龄及多期变质增生

大别山北部榴辉岩及英云闪长质片麻岩的锆石U-Pb年龄分析表明：北部榴辉岩相峰期变质时代为226～230Ma左右;北部塔儿河一带英云闪长质片麻岩经历过印支期变质事件;大别山北部与南部超高压岩石中一致的（226～230Ma）高压或超高压变质年龄表明,北部镁铁-超镁铁质岩带中部分岩石也曾作为扬子俯冲陆壳的一部分,在印支期发生过高压或超高压变质作用;本区锆石发生过两期变质增生事件,一是印支期高压或超高压变质,另一期是燕山期热变质事件;榴辉岩及英云闪长质片麻岩的原岩形成时代为晚元古代;锆石U-Pb年龄可用多期变质增生模型来解释。     

福建中部丁家山铅锌矿床矿物学特征及其指示意义

丁家山铅锌矿床位于梅仙矿田东南部，矿区内普遍发育石榴子石、辉石、绿帘石等脉石矿物，为探讨该矿床成因，对该矿床脉石矿物进行了电子探针、激光剥蚀电感耦合等离子质谱仪(LA-ICP-MS)原位U-Pb定年和微量元素分析。结果表明，石榴子石主要为钙铁-钙铝榴石固溶体系列，含有少量的锰铝榴石和铁铝榴石；辉石为透辉石-钙铁辉石-钙锰辉石固溶体系列；绿帘石族矿物属于绿帘石范畴。石榴子石的²⁰⁶Pb/²³⁸U下交点年龄为143.7 Ma,与成矿花岗岩年龄接近。依据石榴子石原位微量元素特征差异及Eu异常将石榴子石分为钙铁榴石(I型)和钙铁-钙铝榴石(II型)两类。钙铁榴石整体呈现轻稀土富集，重稀土亏损的稀土配分模式，I-1型钙铁榴石Eu具有明显的负异常，I-2型钙铁榴石Eu具有明显的正异常；钙铁-钙铝榴石整体呈现重稀土富集，轻稀土亏损的稀土配分模式，II-1型钙铁-钙铝榴石Eu具有明显的负异常，II-2型钙铁-钙铝榴石Eu具有明显的正异常。上述特征表明，石榴子石核部环境为弱氧化-弱还原，边部为氧化环境。综合地质学、矿物学、地质年代学数据以及地球化学特征，本文认...     

山东、辽宁金伯利岩中石榴石的类型、标型特征及其与金刚石的关系

金伯利岩中的镁铝榴石是寻找金刚石的重要指示矿物。镁铝榴石的Cr2O3、CaO等氧化物含量及其颜色、折光率等物理光学性质可作为这种石榴石的标型特征。 本文将山东、辽宁等地金伯利岩中的石榴石的电子探针分析结果按分子数配分的方法计算了端员分子百分数及其他化学参数。用MPV—1显微光度仪测定了石榴石的透射率色散值,通过计算求得颜色指数。按Dawson等人的分类,本次研究样品以铬镁铝榴石为主,其次是低钙-铬镁铝榴石、钙铬-镁铝榴石和镁铬-钙铬-镁铝榴石;钛镁铝榴石和钙镁铝-铁铝榴石等少量。作者用铬、钙、镁三组份数绘制了石榴石与金刚石关系判别图解,分为五个区(A、B、C、D、E)、落入A区的低钙-铬镁铝榴石、铬镁铝榴石和钙铬-镁铝榴石等与金刚石的形成关系最密切。     

西岭矿区酸性熔岩中石榴石斑晶的特征、成因与成岩意义

西岭矿区酸性熔岩中石榴石斑晶属铁铝榴石,是在20-30 kbar压力下较早从岩浆中品出的斑晶矿物;由于斜长石斑晶发生不一致熔融结晶作用,故具有斜长石反应边。酸性熔岩中含有铁铝榴石高压斑晶及铁铝榴石中含有14.42-21.40％的镁铝榴石分子,是岩浆物质来自深源的标志。石榴石是重稀土选择型矿物。西华山黑云母花岗岩中的铁铝榴石是铁铝榴石-锰铝榴石,其特征与成岩成矿意义均不同于西岭矿区铁铝榴石斑晶。     

Roles of xenomelts,xenoliths, xenocrysts,xenovolatiles, residues,and skarns in the genesis,transport, and localization of magmatic Fe-Ni-Cu-PGE sulfides and chromite

Most sulfide-rich magmatic Ni-Cu-(PGE) deposits form in dynamic magmatic systems by partial melting S-bearing wall rocks with variable degrees of assimilation of miscible silicate and volatile components, and generation of barren to weakly-mineralized immiscible Fe sulfide xenomelts into which Ni-Cu-Co-PGE partition from the magma. Some exceptionally-thick magmatic Cr deposits may form by partial melting oxide-bearing wall rocks with variable degrees of assimilation of the miscible silicate and volatile components, and generation of barren Fe ± Ti oxide xenocrysts into which Cr-Mg-V ± Ti partition from the magma. The products of these processes are variably preserved as skarns, residues, xenoliths, xenocrysts, xenomelts, and xenovolatiles, which play important to critical roles in ore genesis, transport, localization, and/or modification. Incorporation of barren xenoliths/autoliths may induce small amounts of sulfide/chromite to segregate, but incorporation of sulfide xenomelts or oxide xenocrysts with dynamic upgrading of metal tenors (PGE > Cu > Ni > Co and Cr > V > Ti, respectively) is required to make significant ore deposits. Silicate xenomelts are only rarely preserved, but will be variably depleted in chalcophile and ferrous metals. Less dense felsic xenoliths may aid upward sulfide transport by increasing the effective viscosity and decreasing the bulk density of the magma. Denser mafic or metamorphosed xenoliths may also increase the effective viscosity of the magma, but may aid downward sulfide transport by increasing the bulk density of the magma. Sulfide wets olivine, so olivine xenocrysts may act as filter beds to collect advected finely dispersed sulfide droplets, but other silicates and xenoliths may not be wetted by sulfides. Xenovolatiles may retard settling of – or in some cases float – dense sulfide droplets. Reactions of sulfide melts with felsic country rocks may generate Fe-rich skarns that may allow sulfide melts to fractionate to more extreme Cu-Ni-rich compositions. Xenoliths, xenocrysts, xenomelts, and xenovolatiles are more likely to be preserved in cooler basaltic magmas than in hotter komatiitic magmas, and are more likely to be preserved in less dynamic (less turbulent) systems/domain/phases than in more dynamic (more turbulent) systems/domains/phases. Massive to semi-massive Ni-Cu-PGE and Cr mineralization and xenoliths are often localized within footwall embayments, dilations/jogs in dikes, throats of magma conduits, and the horizontal segments of dike-chonolith and dike-sill complexes, which represent fluid dynamic traps for both ascending and descending sulfides/oxides. If skarns, residues, xenoliths, xenocrysts, xenomelts, and/or xenovolatiles are present, they provide important constraints on ore genesis and they are valuable exploration indicators, but they must be included in elemental and isotopic mass balance calculations.     

Mountains,nations, parks,and conservation

Between 1985 and 1991, two new mountain protected areas (MTNPA) covering more than 35,000 km² and based on participatory management models — the Makalu-Barun National Park and Conservation Area, Nepal, and Qomolangma Nature Preserve, Tibet Autonomous Region — were successfully established through the collaborative efforts of Woodlands Mountain Institute and conservationists in China and Nepal. Characteristics common to both projects include the importance of establishing (1) effective rationales, (2) local support constituencies, (3) a senior advisory group, (4) a task force, (5) linkages between conservation and development, and (6) fund raising mechanisms. The lessons derived from the experiences of Woodlands Mountain Institute are of significant value to others in preserving MTNPA. Increased collaboration and communication between all interested in conservation, however, will remain a critical component for expanding mountain protected area coverage to throughout the world.     

Parents,permission, and possibility: Young women,college, and imagined futures in Gujarat,India

This article advances critical geographies of youth through examining the spatiality implicit in the imagined futures of young women in rural India. Geographers and other scholars of youth have begun to pay more attention to the interplay between young people’s past, present, and imagined futures. Within this emerging body of scholarship the role of the family and peer group in influencing young people’s orientations toward the future remain underexamined. Drawing on eleven months of ethnographic fieldwork, my research focuses on a first generation of college-going young women from socioeconomically marginalized backgrounds in India’s westernmost state of Gujarat. I draw on the “possible selves” theoretical construct in order to deploy a flexible conceptual framework that links imagined post-educational trajectories with motivation to act in the present. In tracing the physical movement of these young women as they navigate and complete college, my analysis highlights the ways in which particular kinds of spaces and spatial arrangements facilitate and limit intra- and inter-generational contact, and the extent to which this affects young women’s conceptions of the future. I conclude by considering the wider implications of my research for ongoing debates surrounding youth transitions, relational geographies of age, and education in the Global South.     

Comparative study of As,Cd, Cu,Cr, Mg,Mn, Ni,Pb and Zn concentrations between sediment and water from estuary and port

The contents of As, Cd, Cu, Cr, Mg, Mn, Ni, Pb and Zn have been determined in sediment and water samples from Valle de las Garzas estuary and Port Manzanillo (Colima, Mexico) using ICP-AES. The concentrations of these elements were used for a comparative study to determine the distribution of heavy metals and to evaluate which elements reflect natural or anthropogenic backgrounds. For this purpose, seven sampling points were selected: Four of them correspond to the lagoon, and three were situated in the port. Statistical analysis of the mineral content was assessed. Initially, data comparison was assessed by statistical tests for each variable. Principal component analysis was then applied considering the influence of all variables at the same time by obtaining the distribution of samples according to their scores in the principal component space. In this way, four studies were carried out: (1) study of sediments collected during the dry season; (2) study of sediments collected during the rainy season; (3) comparative study between sediments from rainy and dry season; and (4) study of water composition collected during rainy season. From the results of the performed analyses, it can be concluded that metals distribution pattern reflected natural and anthropogenic backgrounds (e.g., sediments from the lagoon, situated at the beginning of the rain channel, presented high contents of Zn and Cu, perhaps related to anthropogenic activities or the influence of igneous sediments).     

Partition coefficients of Hf,Zr, and REE between zircon,apatite, and liquid

Concentration ratios of Hf, Zr, and REE between zircon, apatite, and liquid were determined for three igneous compositions: two andesites and a diorite. The concentration ratios of these elements between zircon and corresponding liquid can approximate the partition coefficient. Although the concentration ratios between apatite and andesite groundmass can be considered as partition coefficients, those for the apatite in the diorite may deviate from the partition coefficients. The HREE partition coefficients between zircon and liquid are very large (100 for Er to 500 for Lu), and the Hf partition coefficient is even larger. The REE partition coefficients between apatite and liquid are convex upward, and large (D=10–100), whereas the Hf and Zr partition coefficients are less than 1. The large differences between partition coefficients of Lu and Hf for zircon-liquid and for apatite-liquid are confirmed. These partition coefficients are useful for petrogenetic models involving zircon and apatite.     

Coprecipitation of Ti,Mo, Sn and Sb with fluorides and application to determination of B,Ti, Zr,Nb, Mo,Sn, Sb,Hf and Ta by ICP-MS

We examined the coprecipitation behavior of Ti, Mo, Sn and Sb in Ca–Al–Mg fluorides under two different fluoride forming conditions: at < 70 °C in an ultrasonic bath (denoted as the ultrasonic method) and at 245 °C using a Teflon bomb (denoted as the bomb method). In the ultrasonic method, small amounts of Ti, Mo and Sn coprecipitation were observed with 100% Ca and 100% Mg fluorides. No coprecipitation of Ti, Mo, Sn and Sb in Ca–Al–Mg fluorides occurred when the sample was decomposed by the bomb method except for 100% Ca fluoride. Based on our coprecipitation observations, we have developed a simultaneous determination method for B, Ti, Zr, Nb, Mo, Sn, Sb, Hf and Ta by Q-pole type ICP-MS (ICP-QMS) and sector field type ICP-MS (ICP-SFMS). 9–50 mg of samples with Zr–Mo–Sn–Sb–Hf spikes were decomposed by HF using the bomb method and the ultrasonic method with B spike. The sample was then evaporated and re-dissolved into 0.5 mol l^− 1 HF, followed by the removal of fluorides by centrifuging. B, Zr, Mo, Sn, Sb and Hf were measured by ID method. Nb and Ta were measured by the ID-internal standardization method, based on Nb/Mo and Ta/Mo ratios using ICP-QMS, for which pseudo-FI was developed and applied. When 100% recovery yields of Zr and Hf are expected, Nb/Zr and Ta/Hf ratios may also be used. Ti was determined by the ID-internal standardization method, based on the Ti/Nb ratio from ICP-SFMS. Only 0.053 ml sample solution was required for measurement of all 9 elements. Dilution factors of ≤ 340 were aspirated without matrix effects. To demonstrate the applicability of our method, 4 carbonaceous chondrites (Ivuna, Orgueil, Cold Bokkeveld and Allende) as well as GSJ and USGS silicate reference materials of basalts, andesites and peridotites were analyzed. Our analytical results are consistent with previous studies, and the mean reproducibility of each element is 1.0–4.6% for basalts and andesites, and 6.7–11% for peridotites except for TiO₂.     

Entropy,materials, and posterity

Materials and energy are the interdependent feedstocks of economic systems, and thermodynamics is their moderator. It costs energy to transform the dispersed minerals of Earth's crust into ordered materials and structures. And it costs materials to collect and focus the energy to perform work — be it from solar, fossil fuel, nuclear, or other sources. The greater the dispersal of minerals sought, the more energy is required to collect them into ordered states.But available energy can be used once only. And the ordered materials of industrial economies become disordered with time. They may be partially reordered and recycled, but only at further costs in energy. Available energy everywhere degrades to bound states and order to disorder — for though entropy may be juggled it always increases. Yet industry is utterly dependent on low entropy states of matter and energy, while decreasing grades of ore require ever higher inputs of energy to convert them to metals, with ever increasing growth both of entropy and environmental hazard.Except as we may prize a thing for its intrinsic qualities — beauty, leisure, love, or gold — low-entropy is the only thing of real value. It is worth whatever the market will bear, and it becomes more valuable as entropy increases. It would be foolish of suppliers to sell it more cheaply or in larger amounts than their own enjoyment of life requires, whatever form it may take. For this reason, and because of physical constraints on the availability of all low-entropy states, the recent energy crises is only the first of a sequence of crises to be expected in energy and materials as long as current trends continue.The apportioning of low-entropy states in a modern industrial society is achieved more or less according to the theory of competitive markets. But the rational powers of this theory suffer as the world grows increasingly polarized into rich, over-industrialized nations with diminishing resource bases and poor, supplier nations with little industry. The theory also discounts posterity, the more so as population density and percapita rates of consumption continue to grow. A new social, economic, and ecologic norm that leads to population control, conservation, and an apportionment of low-entropy states across the generations is needed to assure to posterity the options that properly belong to it as an important but voiceless constituency of the collectivity we call mankind.

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Zusammenfassung Rohstoffe und Energie sind die Grundlagen unseres ökonomischen Systems, das von den Gesetzen der Thermodynamik bestimmt wird. Es kostet Energie, um die auf der Erde verteilten Rohstoffe diesem System zuzuführen. Andererseits braucht man Rohstoffe, um die Energie nutzbar zu machen.Die verfügbare Energie kann nur einmal genutzt werden und das Material verbraucht sich. Verbrauchtes Material kann teilweise zur weiteren Nutzung zurückgeführt werden, das kostet wiederum Energie. Die verfügbare Energie nimmt überall ab, und einmal geschaffene Ordnung gerät wieder in Unordnung — das heißt, die Entropie des Systems nimmt ständig zu. Die Industrie ist jedoch abhängig von einem niedrigen Entropiezustand sowohl der Materie als auch der Energie.Je ärmer die Erze sind, um so höher wird die Energie sein, um sie in Metalle umzuwandeln, wobei die Entropie und die Belastung der Umwelt ständig zunimmt.Außer den Dingen, die wir wegen höherer ideeller Werte schätzen, ist eine niedrige Entropie der einzige realistische Wertmaßstab, und der wirkliche Wertzuwachs ist nur an einer höheren Entropie zu messen. Es ist unverantwortlich, Dinge, die eine höhere Entropie bedingen, billiger zu verkaufen oder in größerer Menge zu erzeugen, als unbedingt notwendig ist. Da wir dies heute in unserem Handeln nicht berücksichtigen, ist die derzeitige Energiekrise nur der Anfang einer Folge von Krisen, die Energie und Rohstoffe betreffen, solange wir nicht umdenken.Die Verteilung von niedriger Entropie in einer modernen Industriegesellschaft wird mehr oder weniger nach dem Prinzip der konkurrierenden Märkte erreicht. Das selbstregulierende System gerät jedoch mit zunehmender Polarisierung in reiche Industrienationen mit abnehmenden Ressourcen und armen Nationen mit geringer Industrialisierung in Unordnung. Dieses Prinzip berücksichtigt auch nicht die Nachwelt, vor allem wenn die Bevölkerungsdichte stetig zunimmt und die Konsumbedürfnisse anwachsen. Es sind neue soziale, ökonomische und ökologische Normen notwendig, die zur Populationskontrolle, zur Erhaltung der Umwelt und zu einem Zustand niedriger Entropie für zukünftige Generationen führen. Die nach uns kommenden Menschen haben ein Anrecht darauf.

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Résumé Matériaux et énergie sont les sources des systèmes économiques et sont régis par les lois de la thermodynamique. Il faut de l'énergie pour transformer les ressources minérales dispersées dans la croûte terrestre en matériaux et structures ordonnancées. Et il faut des matériaux pour receuillir et concentrer l'énergie, qu'elle soit solaire ou atomique, ou provienne de combustibles fossiles ou d'autres sources. Plus les minéraux recherchés sont dispersés et plus est côuteuse l'énergie pour leur donner une ordonnance.Or l'énergie disponsible ne peut être utilisée qu'une seule fois. Et les matériaux ordonnancés des économies industrielles se dégradent avec le temps. Ils peuvent être remis partiellement en état et recyclés, mais pour cela il faut de nouveau de l'énergie. Partout l'énergie disponible se dégrade et l'ordre devient désordre; -malgré toutes les jongleries possibles l'entropie augmente toujours.L'industrie dépend clairement d'états de basse entropie tant en ce qui concerne les matériaux que l'énergie, tandis que plus pauvres sont les minerais, plus; élevée est l'énergie à mettre en jeu pour en extraire les métaux, avec toujours augmentation à la fois de l'entropie et de la degradation des milieux.A l'exception de ce que nous apprécions pour leur valeur intrinsèque — la beauté, le loisir, l'amour ou l'or — la basse entropie est la seule chose de réelle valeur. Son prix est réglé par le marché, et sa valeur augmente au fur et à mesure que l'entropie s'accroît. Ceux qui en disposent seraient insensés de la vendre à bas prix ou en quantité supérieure à ce qu'exige leur propre niveau de vie. Pour cette raison, et à cause des contraintes physiques liées à la disponibilité en états de basse entropie, la récente crise d'énergie n'est, en ce qui concerne les matières premières et l'énergie, que la première d'une série de crises auxquelles il faut s'attendre aussi longtemps que se poursoit la marche actuelle des étènements.Dans les sociétés industrielles modernes, les approvisionnement en basse entropie s'effectuent plus ou moins conformément à la théorie de la concurrence des marchés. Cependant la rationalité de cette théorie se ressent de l'accentuation croissante de la polarisation, à l'échelle du monde, en nations riches, surindustrialisées, à ressources de base décroissantes, et en nations pauvres, sous-industrialisées, mais fournisseurs de resources-naturelles. De plus cette théorie ne tient pas compte de notre postérité, et ce, en face d'une densité de population et d'un taux de la consommation par tête d'habitant en augmentation continue.Nous avons donc besoin de nouvelles normes sociales, économiques et écologiques qui conduisent au contrôle de la population, à la conservation et à la répartition des états de basse entropie à travers les générations pour assurer à notre postérité les options qui leur riviennent de droit comme une constituante importante, mais encore muette, de la collectivité que nous appelons l'Humanité.

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Dedicated with appreciation to Nicholas Georgescu-Roegen, distinguished economist, realist among cornucopians     

Models,validation, and applied geochemistry: Issues in science,communication, and philosophy

Models have become so fashionable that many scientists and engineers cannot imagine working without them. The predominant use of computer codes to execute model calculations has blurred the distinction between code and model. The recent controversy regarding model validation has brought into question what we mean by a ‘model’ and by ‘validation.’ It has become apparent that the usual meaning of validation may be common in engineering practice and seems useful in legal practice but it is contrary to scientific practice and brings into question our understanding of science and how it can best be applied to such problems as hazardous waste characterization, remediation, and aqueous geochemistry in general. This review summarizes arguments against using the phrase model validation and examines efforts to validate models for high-level radioactive waste management and for permitting and monitoring open-pit mines. Part of the controversy comes from a misunderstanding of ‘prediction’ and the need to distinguish logical from temporal prediction. Another problem stems from the difference in the engineering approach contrasted with the scientific approach. The reductionist influence on the way we approach environmental investigations also limits our ability to model the interconnected nature of reality. Guidelines are proposed to improve our perceptions and proper utilization of models. Use of the word ‘validation’ is strongly discouraged when discussing model reliability.     

Pebbles,Shapes, and Equilibria

The shape of sedimentary particles may carry important information on their history. Current approaches to shape classification (e.g. the Zingg or the Sneed and Folk system) rely on shape indices derived from the measurement of the three principal axes of the approximating tri-axial ellipsoid. While these systems have undoubtedly proved to be useful tools, their application inevitably requires tedious and ambiguous measurements, also classification involves the introduction of arbitrarily chosen constants. Here we propose an alternative classification system based on the (integer) number of static equilibria. The latter are points of the surface where the pebble is at rest on a horizontal, frictionless support. As opposed to the Zingg system, our method relies on counting rather than measuring. We show that equilibria typically exist on two well-separated (micro and macro) scales. Equilibria can be readily counted by simple hand experiments, i.e. the new classification scheme is practically applicable. Based on statistical results from two different locations we demonstrate that pebbles are well mixed with respect to the new classes, i.e. the new classification is reliable and stable in that sense. We also show that the Zingg statistics can be extracted from the new statistics; however, substantial additional information is also available. From the practical point of view, E-classification is substantially faster than the Zingg method.