The system diopside-nepheline-leucite

The system diopside-nepheline-leucite, representing a join in the undersaturated part of the system nepheline (Ne)-kalsilite (Ks)-CaO-MgO-SiO₂, has been investigated at atmospheric pressure. The system is pseudoternary and cuts the primary phase volumes of forsterite solid solution (Fo_ss), diopside solid solution (Di_ss), nepheline solid solution (Ne_ss), carnegieite solid solution (Cg_ss), and leucite solid solution (Lc_ss). Melilite (Mel) occurs as a subliquidus phase. The phase diagram has two four-phase points: 1. one at 1275±5° C and Di₆₀Ne₈Lc₃₂ where liquid coexists with Fo_ss, Di_ss and Lc_ss, corresponding to olivine (Ol) leucitite; 2. the other at 1194±5° C and Di_27.5Ne_29.5Lc₄₃ where Ne_ss, Fo_ss and Lc_ss coexist with liquid, corresponding to Ol-Ne italite. With decreasing temperature, liquid moves from point (1) to a five-phase assemblage (3) where liquid is in equilibrium with Fo_ss, Di_ss, Mel and Lc_ss (1258±5°C), which is representative of Ol-Mel-leucitite. From point (2) liquid moves to a second five-phase assemblage (4), where Fo_ss, Mel, Ne_ss, Lc_ss and liquid are in equilibrium (1175±5°C, corresponding to a Lc-Ne katungite. The assemblage Fo_ss+Ne_ss+Di_ss+Mel+Lc_ss+ liquid, is reached between 1168° and 1100° C and corresponds to Ol-Mel-Ne leucitite. Fo_ss reacts with liquid and disappears. Near the point (1) it disappears at 1135±10° C, whereas near the point (2) it reacts out at 1060±10° C. Near the join Di-Ne it disappears at 950±10° C. The final assemblage in the system is representative of Mel-Ne leucitite.Presented at the symposium Recent Advances in the Studies of Rocks and Minerals at High Pressures and Temperatures held in Montreal, 1972. Jointly sponsored by the International Mineralogical Association and the Commission on Experimental Petrologie.     

The Cu-Zn-S system

The phase relations in the Cu-Zn-S system were studied at temperatures ranging from 100 ° to 1050 °C with emphasis on the 500 ° and 800 °C isotherms. All experiments were performed in closed, evacuated silica tubes in which vapor always is a phase. Ternary phases did not appear in any of these experiments. At 800 °C tie-lines exist between cubic ZnS (sphalerite) and the digenite-chalcoite solid solution, between ZnS and three CuZn alloys (, , ) and between ZnS and ZnCu liquid containing from zero to about 30 wt % Cu. Only the cubic, sphalerite, form of ZnS was encountered in the present study. At 800 °C the solid solution of ZnS in Cu₂S is 7.0 ± 1 wt % and the solid solution of Cu₂S in ZnS is less than 1.0 wt %. At lower temperatures ZnS coexists with all other phases once they become stable, i.e., -CuZn (<598 °C), CuS (<507 °C), and blue-remaining covellite (<157 °C). At 500 °C the solid solution of ZnS in Cu₂S is 1.5±0.5 wt % and that of Cu₂S in ZnS is less than 0.1 wt %. The presence of ZnS depresses the temperature of the hexagonal cubic inversion in Cu₂S by about 13 °C, but does not measurably affect the temperature of the monoclinic hexagonal inversion in Cu₂S nor that of the cubic cubic inversion in Cu₉S₅. The coexistence in nature of sphalerite and copper-sulfides is discussed in light of the low temperature phase relations in the Cu-Zn-S system.

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Zusammenfassung Die Phasengleichgewichtsredaktionen des Dreistoffsystems Cu-Zn-S wurden über einen weiten Temperaturbereich, nämlich von 100 °C bis zu 1050 °C und dabei besonders nachdrücklich die 500 ° und 800 °C-Isothermen, untersucht. Alle Experimente wurden in abgeschmolzenen und vorher evakuierten Quarzglasampullen durchgeführt, in welchen eine Dampfphase (vapor) stets gegenwärtig war. In keinem der Experimente war das Vorhandensein einer ternären Phase zu verzeichnen. Bei 800 °C verlaufen Konodenscharen vom kubischen ZnS (Zinkblende) zur Digenit-Kupferglanz-Mischkristallreihe, ferner Konoden zwischen ZnS und drei Cu-Zu-Legierungen (, , ) und zwischen ZnS und einer Zn-Cu-Schmelze von 0 bis ca. 30 Gew.-% Cu. In der hier vorliegenden Arbeit trat nur kubisches ZnS (Zinkblende) auf. Cu₂S vermag bei 800 °C 7,0±1 Gew.-% ZnS in fester Lösung aufzunehmen, während die Löslichkeit von Cu₂S in ZnS weniger als 1,0 Gew.-% beträgt. Mit zunehmender Temperaturerniedrigung koexistiert ZnS mit allen übrigen Phasen des Systems, sobald diese stabil werden, z. B. -CuZn (<598 °C), CuS (<507 °C) und blaubleibender Covellin (<157 °C). Bei 500 °C beträgt die Löslichkeit von ZnS in Cu₂S nur noch 1,5±0,5 Gew.-% und die von Cu₂S in ZnS weinger als 0,1 Gew.-%. Die Gegenwart von ZnS erniedright die Inversionstemperatur von hexagonalem kubischen Cu₂S um etwa 13 °C, hat aber weder einen meßbaren Einfluß auf die Inversionstemperatur des monoklinen hexagonalen Cu₂S noch auf die kubisch kubische Inversion des Cu₉S₅. Angeischts der im Cu-Zn-S-System ermittelten Phasenbeziehungen bei niedrigen Temperaturen werden die Koexistenz natürlicher Zinkblende mit Kupfersulfiden diskutiert.

     

The system Pb-As-S

Silica-tube quenching experiments and gold-tube pressure experiments were used to study phase relations in the PbS-rich portion of the system Pb-As-S. Emphasis was placed on determining the P-T-X stability relations of jordanite, the most Pb-rich of the synthetic Pb-As-S compounds. Jordanite, Pb₉As₄S₁₅, is stable below 549 ± 3° C, at which temperature it melts to galena, liquid, and a sulfur-rich vapor phase. Confining pressures of up to 2 Kb do not measurably change this reaction temperature. Density measurements on synthetic material show that the jordanite cell contains 3 (Pb₉As₄S₁₅); space group P2₁/m requires that the cell content be expressed as either Pb_28–xAs₁₂S_46–x or Pb_26+xAs₁₂S_44+x, with the former much more probable from a structural point of view. In both cases 0.8 < x < 1.4 and the situation is thus quite different from the usual case of defect structures, such as pyrrhotite, Fe_1–xS, which shows considerable range of solid solution. Heating experiments on natural gratonite (Pb₉As₄S₁₅) show that this mineral is most probably a low-temperature dimorph of jordanite, the inversion occurring below 250° C. Experiments have also confirmed the extensive substitution of Sb for As in jordanite, as suspected from chemical analyses of the isostructural mineral geocronite (Pb_28–x(As,Sb)₁₂S_46–x).

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Zusammenfassung Durch Abschreckversuche mit Hilfe von Quarz- und Gold-Druckampullen wurden die Phasenbeziehungen im PbS-reichen Teil des Pb-As-S-Systems studiert. Besonderer Wert wurde auf die Feststellung der P-T-X-Stabilitätsverhältnisse des Jordanits, des Pb-reichsten Phase der synthetischen Pb-As-S-Reihe, gelegt. Jordanit (Pb₉As₄S₁₅) ist unterhalb 549 ± 3° C stabil, wo er sich semikongruent zu PbS, einer Schmelze und einer schwefelreichen Dampfphase zersetzt. Drucke bis zu 2 kb ergaben keine meßbaren Änderungen dieser Reaktionstemperatur. Dichtemessungen am synthetischen Material weisen darauf hin, daß die Jordanitzelle 3 × (Pb₉As₄S₁₅) enthält. Die Raumgruppe P2₁/m fordert entweder die Formel Pb_28–xAs₁₂S_46–x oder Pb_26+xAs₁₂S_44+x, wobei die erstere Form strukturell wahrscheinlicher zu sein scheint. In beiden Fällen ist 0.8 < x < 1.4 und weicht vom gebräuchlichen Begriff der Defektstrukturen, wie z.B. beim Pyrrhotin (Fe_1–xS) ab, wie das bemerkenswerte Mischkristallfeld zeigt. Erhitzen von natürlichem Gratonit (Pb₉As₄S₁₅) zeigt, daß dieses Mineral sehr wahrscheinlich eine dimorphe Tieftemperaturphase des Jordanits ist. Die Umwandlung erfolgt unterhalb 250° C. Außerdem wurde eine umfangreichere Substitution von As durch Sb im Jordanit festgestellt, was nach den chemischen Analysen des isostrukturellen Geochronits Pb_28–x(As,Sb)₁₂S_46–x) zu erwarten war.

     

The Amazon shearing system

In the Amazon region there is a trough-like east-west feature hidden by young sediments. In the trough itself, which is transversely split up, there are Palaeozoic strata which have survived because of the subsidence. This probably took place when the Gondwana continent broke up whereby basaltics intruded. These are attributed to the Jurassic period although they are normally found as sills in the Palaeozoic sediments of the Amazon region.In addition, the Amazon Graben exhibits dislocation by a transcurrent fault system such that the northern block (= Guayana Shield) is transposed considerably to the west when compared with the southern block (Brazilian Shield). The Amazon transcurrent fault is a left-handed shearing system.Relations between the Amazon shearing system and the West African Bénoué Graben, between the sigmoidal bulge of the western South American shore line and the West African continental margin and the proximity of the equator are discussed.     

The Baltic-Kattegat-Skagerrak estuarine system

Measurements of alkalinities and calcium concentrations in the Baltic Sea indicate that there has been a slight increase in both these parameters over the last century. These increases may have been caused by the leaching of limestone by acid rain. About ten percent of the nutrients are exported from the Baltic to the Kattegat; however, very little, if any, alkalinity is stored in the Baltic since river input and system output are approximately equal. Since the precipitation and evaporation are almost equal in the Baltic Sea, corrections are not needed for river inputs.     

The system Fe-FeO revisited

The results of a reconnaissance investigation of melting relationships in the system Fe-FeO at 16 GPa were recently described by Kato and Ringwood (1989). The principal sources of uncertainties in those experiments were caused by loss of FeO to sample capsules during runs and the estimation of sample temperatures by an indirect method, based upon a prior calibration of the relationship between power input and temperature. A further set of 24 runs at 16 GPa has been carried out using improved experimental techniques. The melting temperatures of iron and wüstite at 16 GPa are found to be 1945±20° C and 1875±25° C respectively. (Quoted errors do not include possible effects of pressure on thermocouple emf). The Fe-FeO eutectic is now located at 10±2 wt% FeO and 1670±20° C (previously 15.5±3 wt% FeO and 1700±25° C). The new determination of the depression of the melting point of iron by solution of FeO is 27.5° C/wt% FeO as compared to the previous value of 23° C/wt% FeO. The present results show that the contraction of the liquid immiscibility field in the system at high pressure is somewhat larger than was estimated previously. This study confirms the general topology of high pressure phase relationships in the Fe-FeO system obtained by Kato and Ringwood (1989) and has similar implications for the process of core formation within the Earth.     

The transport system of Slovenia

The article presents the global and regional transport-geographic position of Slovenian territory, the role and importance of individual modes of transport, and degree of motorization and its spatial impact.     

The lithosphere-asthenosphere system in Fennoscandia

We present a summary of the available information on Rayleigh-wave dispersion data for the Fennoscandian region. The observations have been combined to produce regional dispersion relations which have then been subjected to the “hedgehog” inversion procedure. The results are presented on a map outlining the thickness of the lid and the shear velocities in both the lid and the asthenosphere channel. Lid thickness up to around 135 km is found in the Bothnia-north-central Finland area with, if any, weak shear velocity contrast to the underlying layer. The surrounding areas are characterized by lid thickness up to around 75 km; a stronger low-velocity zone to lid contrast may be found in the Caledonian and Baltic Sea area (0.25÷0.45 km/s). Taking into account Moho depth data and the aforementioned results, a map of the lithosphere-asthenosphere system was derived.     

输导体系研究综述

输导体系作为联结生、储、盖、圈的桥梁和纽带,是油气运移成藏研究的关键,也是现油气运移研究的薄弱环节。输导通道宏观上主要分为储集层、断裂和不整合输导体系,且其具有独立性、时空性、复杂性、输储转化性以及运移油气时的非均一性和幕式运移等特点。储集层、断裂、不整合输导体系及各输导体系的空间组合或时空配置不同时,其输导机制和输导性能不同。在综述前人对输导体系的研究后,总结现输导体系研究的问题并提出今后研究的主要体现。     

鄂尔多斯盆地白垩系含水层系统分析

从地下水含水层系统的角度对鄂尔多斯盆地白垩系地下水系统进行了划分和分析。由于下白垩系统保安群为一套陆相碎屑岩建造,岩性复杂,由砂岩、粉砂岩和泥岩组成的频繁交替、重复叠置的多层层状结构,决定了鄂尔多斯白垩系自流水盆地是多层结构的地下水系统。这种重复叠置的多层层状地质结构,决定了地下水含水层系统的多层性、承压性及层与层之间的相对封闭性。根据沉积旋回和含水介质的性质,在全盆地范围内把白垩系地下水系统从上向下划分为:罗汉洞含水岩组、环河含水岩组和洛河含水岩组。通过对这3大含水岩组分别进行了分析认为,洛河含水岩组和环河含水岩组分布范围广、含水层厚度大、天然资源丰富,是盆地区具供水意义的主要含水岩组。罗汉洞含水岩组因分布面积小,含水层厚度差异大、水质变化大,除陇东地区外,大部分地区供水价值较小。     

The system diopside-ureyite at 20 Kb

The join diopside (CaMgSi₂O₆) — ureyite (NaCrSi₂O₆) was studied at pressures of 1 atm, 1 kb, 5 kb, and 20 kb using gel mixtures as starting materials. All runs except those at 1 atm were made under hydrous conditions. The data show that the solubility of ureyite in diopside decreases with increasing pressure. At 20 kb the maximum ureyite content of diopside is 13 weight percent (4.6% Cr₂O₃) as compared to 24 weight percent at 1 atm. It is predicted that pyroxenes that have equilibrated at depths >140 km will not contain a ureyite component; rather Cr will enter diopside in the form of a CaCr(CrSi)O₆ component. Pyroxenes containing this component were found as metastable phases at 20 kb.     

The Baikal system of rift valleys

The Baikal system of rift valleys has no evident structural connections with the World Rift System. The peculiar features of its structure, morphology and volcanicity reflect this isolation. The spatial position and major structural features of the system are determined where the central segment (the South Baikal depression) is confined to the junction of two major lithospheric plates, the Precambrian Siberian platform and the heterogenous folded framework of Sayan—Baikal. The contrasting structures and thermodynamic conditions of these two plates, and the deep nature of the suture zone developed between them, have been responsible for the location of crustal extension and proto-rift formation within the Baikal depression proper, first initiated not later than Eocene and then propagating to zones both west and northeastwards.     

The European system of capital cities

Capital cities reflect the nature and organization of the states they control. Their functional role is higher in centralized systems, societies where the state is the source of all legitimacy, and countries using Continental Law. It is lower in federal systems, pillarized societies and countries, which are ruled according to a Common Law. The symbolic status of capital cities is higher when the state is the source of all legitimacy, lower in consociationalist societies. Theses processes were responsible for the development of two types of political capital cities and one type of economic and cultural capital cities during the nineteenth century. A partial standardization of the functions and statuses of capital cities occurred later. The European Union is neither a state nor a super-state since its main responsibilities are still in the economic field, it lacks a huge administrative bureaucracy and does not have definitive territorial limits. The European Union has officially three capital cities, Strasbourg, Luxembourg and Brussels. The really important one is Brussels. Its functions are nevertheless quite different from those of national capital cities during the first half of the twentieth century. European capital cities are thriving because most of them managed to become economic metropolises. The result is that the European Union has a complex and rapidly evolving system of capital cities.     

地震快报系统

本文简述了开发地震快报系统的主要技术。     

异珊瑚隔壁的排布系列

异珊瑚原始隔壁数目、后生隔壁的增生部位和方式以及隔壁的排布系列的研究，是探讨异珊瑚的起源、演化和分类的基本前提。通过对3隔壁的Triphyllia和4隔壁的Quadratphyllia二属的研究，结合生物体对称的原则，提出异珊瑚原始隔壁为2条，并认为异珊瑚的后生隔壁发育在原始隔壁所分隔的左右两侧部体腔内缘部位，长隔壁呈树枝状拓布或者末端达中心向某一方面扭曲连接形成轴管构造。依据后生隔壁在体腔内的繁生能力、增殖数量、发生部位、排布方式、分化程度、隔壁始端在外壁中的埋植类型和末端在中心部位的连接类型等方面的不同，异珊瑚隔壁增生大致可划分为7个布系列。     

首波震相跟踪系统

本文简述了首波震相跟踪系统的主要功能和技术。