Mineral resources inventory in the northern part of haiti: A basic rationale for selecting areas of potential mining interest

Agriculture has always been the major source of income of the Republic of Haiti. Only in the late sixties did the Haitian Government decide to move toward industrialization and explotation of natural resources, but no reliable inventory of mineral potential was available. In June 1970 the Resources and Transport Division of the U.N. (now CNRET) undertook a structural analysis of the Caribbean with reference to defining favorable loci for ore disposition. One of the conclusions of this survey was that from the metallogenetic point of view, the Northern part of Haiti was a favorable area for prospecting for habe metal deposits, especially for copper. Those conclusions were acknowleadged with great enthusiams by the Haitian authorities, and they welcomed in July 1971 a UN technical adviser who outlined a first phase of exploration. Following this mission, a “Mineral exploration Project” was created by the Haitian Government with the cooperation of UNDP, and an area of 9000 km² was selected, based on structural, lithological, and metallogenetic reasons, as an exploration target. The most important aspects of this project were:Mineral Exploration—First Phase (1973–1974). The following operations were carried out by a small team: (a) photo interpretation at 1:50,000 and 1:200,000 scale, (b) geological reconnaissance at 1:50,000 scale, (c) geochemical reconnaissance (stream sediment) at 1:50,000 scale. The photo interpretation helped outline zones of particular structural interest and was followed up by ground control studies. Stream sediment geochemical reconnaissance was carried out over half of the project area, following the indications given by the photo geological interpretation. finally, combining all the data, five areas were selected for detailed follow up survey: (1) Terrier Rouge—Perche, (2) Vallieres, (3) Mont-Organise, (4) Limonade, (5) Gros Morne—Le Borgne.Mineral Exploration—Second Phase (1975–1976). The main zones of interest were reduced to a few hundred km² and porphyry copper type deposits appeared to be the most promising target. Detailed geological mapping (1:25,000 to 1:2,000) and soil geochemistry were carried out on the above mentioned five areas, the most promising appearing quickly to be Terrier Rouge-Perges, with porphyry-type copper mineralization. A geophysical survey (IP and Mag) confirmed the geochemical results. At the end of the second phase of exploration (December 1976) two of the five prospects of the Terrier Rouge area have been diamond drilled and appeared to be of potential economic interest. Because of the number and importance of the prospects discovered a third phase of exploration was deemed necessary with the purpose of continuing the detailed prospection work and drilling the other prospects. This third phase started in January 1977 and was expected to last until December 1979. This paper was presented at the International Geological Correlation Program (IGCP) Project 98: “Standards for Computer Applications in Resource Studies” held at Taita Hills, Kenya, November 8–15, 1977.     

Thermal oscillations in a fluid heated from below and cooled to freezing from above

A theoretical discussion is given of the thermal transients and self-sustained oscillations in a fluid, heated at a constant rate below the surface, and cooled from the top strongly enough to allow freezing. Assuming that the fluid is well mixed and that the thickness of the ice is small compared to the fluid depth, it is shown that the system can have zero, one, or two steady states. The ice-covered steady state is stable for small perturbations; however, the ice-free steady state may be unstable with the impulsive addition of a thin ice sheet. Transient developments may include both ice-covered and ice-free states. In the case where no steady state exists the system exhibits periodic self-sustained oscillations. Application of the theory to a laboratory experiment is considered.     

Magnetic Field Line Transport in Anisotropic Magnetic Turbulence: Anomalous, Quasilinear, and Percolative Regimes Versus the Kubo Number

The transport of plasma and of energetic particles because of magnetic turbulence is relevant to many space plasmas, ranging from the planetary magnetospheres to the solar corona and to the heliosphere. Various transport regimes for magnetic field lines can be obtained depending on the Kubo number. Here we show, by means of a numerical simulation, that the Kubo number also determines the level of chaos of the field lines. Weak chaos, closed magnetic surfaces, and anomalous transport regimes are obtained for R≪ 1; widespread chaos, destroyed magnetic surfaces, and quasilinear scaling of the diffusion coefficient for R ≳ 0.3; and global stochasticity as well as percolation scaling of the diffusion coefficient for R≫ 1. This revised version was published online in July 2006 with corrections to the Cover Date.     

Sur la stabilite de certains mouvements particuliers d'un satellite artificiel de la terre soumis aux efforts aerodynamiques

L'auteur considère le mouvement d'un satellite artificiel de la terre évoluant suffisamment près de celle-ci pour qu'on ait à tenir compte des efforts aérodynamiques et en admettant que l'air est un fluide parfait incompressible en mouvement irrotationnel.Il met le problème en équations et, dans le cas d'un satellite de révolution, démontre l'existence de mouvements particuliers où le centre de gravité du satellite a un mouvement circulaire uniforme le satellite tournant uniformément autour de son axe perpendiculaire au plan du cercle. Il donne des conditions suffisantes de stabilité et d'instabilité de ces mouvements au moyen de la méthode de Liapounoff.

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The author considers the motion of an artificial satellite of the Earth revolving sufficiently near it so that the aerodynamic forces can be taken into account. It is supposed that air is a perfect incompressible fluid in irrotational motion.The problem is posed in the form of equations and proves the existence of particular motions in the case of a satellite of revolution when the centre of gravity of the satellite has uniform circular motion, the satellite revolving uniformly around its axis, perpendicular to the plan of the circle.Sufficient conditions for stability and instability of particular motions are given by the method of Liapunov.

     

Apport de la gravimétrie à l'étude de la structure du bassin des Triffa (Maroc nord-oriental) : implications hydrogéologiques

Various techniques (horizontal and vertical derivatives, upward continuation, Euler deconvolution) have been applied to the gravity data from the Triffa's plain and the north flank of the Beni-Snassen massif to delineate various major geological structures such as faults and basins. These results allow the production of a structural map showing the fault systems for the survey area. This map forms the basis for planning future hydrogeological research in this region. To cite this article: D. Khattach et al., C. R. Geoscience 336 (2004).     

Constraining diamond metasomatic growth using C- and N-stable isotopes: examples from Namibia

The present paper provides C- and N-stable isotope characteristics, N-contents and N-aggregation states for alluvial diamonds of known paragenesis from placers along the Namibian coast. The sample set includes diamonds with typical peridotitic and eclogitic inclusions and the recently reported “undetermined” suite of Leost et al. [Contrib. Mineral. Petrol. 145 (2003) 15] which resulted from infiltration of high temperature, carbonate-rich melts. δ¹³C-values range from −20.3‰ to −0.5‰ (n=48) for peridotitic diamonds and from −38.5‰ to −1.6‰ (n=45) for eclogitic diamonds. Diamonds belonging to the “undetermined” suite span a narrower range in δ¹³C from −8.5‰ to −2.7‰ (n=13). When compared with previous studies, diamonds from Namibia are characterised by unusually low proportions of N-free (i.e. Type II) peridotitic and eclogitic diamonds (3% and 2%, respectively) and an unprecedented high proportion of N-rich diamonds (15% and 73%, respectively, have N-contents >600 ppm). δ¹⁵N-values for diamonds of the peridotitic, eclogitic and “undetermined” suites range from −10‰ to +13‰ without correlations with either N-content or δ¹³C. The similarity in N-isotopic composition and the N-rich character of diamonds belonging to the eclogitic, peridotitic and “undetermined” suites is striking and suggests a close genetic relationship. We propose that a large part of the diamonds mined in Namibia formed during metasomatic events of similar style that introduced carbon and nitrogen into a range of different host lithologies.     

Analyse quantitative des faciès carbonatés et cycles T–R de haute fréquence dans le Barrémien du Prébalkan central (Bulgarie)

Within the Emerici zone–Barremense zone biostratigraphic interval, the Barremian deposits of Central Fore-Balkan (Lovech–Veliko Tarnovo shelf) consist of a succession of several formations where alternate terrigenous argillaceous/sandy-dominated facies (Kormjansko Fm., Balgarene Fm.) and carbonate-dominated (‘Urgonian’) facies (Krushevo Fm., Emen Fm.). The qualitative and, particularly, quantitative facies analysis of the carbonate successions observed along 13 detailed cross-sections and in one drill hole show the stacking of about 40 fifth-order T–R cycles induced by numerous eustatic jerks contributing to the progressive settlement of this shelf. These high-frequency cycles of about 100 000 years must be regarded as valuable correlation tools for the subsurface hydrocarbon research. To cite this article: V. Minkovska et al., C. R. Geoscience 336 (2004).     

Solutions for Exterior Orientation in Photogrammetry: A Review

The determination of the attitude, the position and the intrinsic geometric characteristics of the camera is recognised as the fundamental photogrammetric problem. It can be summarised as the determination of camera interior and exterior orientation parameters, as well as the determination of 3D coordinates of object points. The term "exterior orientation"of an image refers to its position and orientation related to an exterior (object space) coordinate system. Several methods can be applied to determine the parameters of the orientation of one, two or more photos. The orientation can be processed in steps (as relative and absolute orientation) but simultaneous methods (such as bundle adjustments) are now available in many software packages. Several methods have also been developed for the orientation of single images. They are based in general on geometric and topological characteristics of imaged objects.
This paper presents a survey of classical and modern methods for the determination of the exterior parameters in photogrammetry, some of which are available as software packages (with practical examples) on the Internet. The methods presented are classified in three principal groups. In the first, a selection of approximate methods for applications that do not require great accuracy is presented. Such methods are also used to calculate values required for iterative processes. In the second group, standard point–based methods derived from collinearity, coplanarity or coangularity conditions are briefly reviewed, followed by line–based approaches. The third group represents orientation methods based on constraints and on concepts of projective geometry, which are becoming of increasing interest for photogrammetrists. In the last section, the paper gives a summary of existing strategies for automatic exterior orientation in aerial photogrammetry.     

Small valley bottom deposits in the sandy districts of the Sarthe basin (France): climatic and/or human origin?

The study of the small valley bottom deposits in a sandy district where several recent erosional events have occurred makes it possible to distinguish deposits, which are caused by climatic oscillations from those induced by both climate and human activities. The coarse alluvium with flints, which reached the main valleys prior to the Subboreal, was transported by greater flows than those which resulted from later human-induced flood discharges, where flints were not evacuated from the small valleys. Radiocarbon dates of peat set those deposits in the Iron Age, in the transition from Antiquity to the Medieval period, at the end of the “optimum climatique de l'an Mil” and during the Little Ice Age. At the present time, human-induced flood discharges reach again the main valleys.