José Alberto Batista Rodríguez

Instituto Superior Minero Metalúrgico de Moa. Las Coloradas, Moa. Holguín, Cuba Tel. (53)(24)(6)8190, Fax: (53)(24)(6) 2290 E–mail: jabatista@ismm.edu.cu

Received: December 1, 2003
Accepted: September 6, 2005

Resumen

Palabras clave: Interpretación aeromagnética, ofiolitas, zonas de fallas, alteraciones hidrotermales, Cuba nororiental.

Abstract

Interpretation of the aeromagnetic survey of northeastern Cuba at scale 1 50 000 is presented. Mainly ophiolitic rocks are characterized by a high magnetic response. The aeromagnetic data was reduced to the pole and the horizontal and vertical gradients, as well as the upward continuation were calculated. To define areas of serpentinized ultrabasic rocks at surface and depth, the magnetic field transformations were interpreted. We discuss lateral extension of outcrops, thickness variation of the ophiolitic rocks, basement extension and fault zones. Hydrothermal alterations indicate associated precious metal secondary mineralization. Operations are planned to limit damage to mining by siliceous material in Fe+Ni laterites.

Key words: Aeromagnetic interpretation, ophiolites, fault zones, hydrothermal alterations, north–eastern Cuba.

INTRODUCTION

The region studied is located on the northeastern sector of Cuba, where important Fe+Ni laterites and chromite deposits outcrop (Figure 1).

Air surveys have become an indispensable tool to geologic mapping and prospecting of mineral deposits in extensive or inaccessible regions, or in areas where geologic mapping is insufficient. It is also a helpful tool to know the distribution of rocks under the sedimentary cover and allocation of mineral bodies.

In the study area, 70% of the rocks outcrop in the Mayarí–Baracoa ophiolitic belt and on the Cretaceous and Paleogene volcanic island arc (Figure 1), largely covered by a thick lateritic crust (Cobiella, 1988, 2000; Quintas, 1989; Iturralde–Vinent, 1995, 1996a,b,c, 1998; Proenza, 1997; Lavaut, 1998; Proenza et al., 1999c; Batista, 1998; Batista and Rodríguez, 2000).

This geology affords efficient application of an aeromagnetic survey due to significant magnetization contrasts (Chang et al., 1990, 1991; Batista, 2002; Batista et al., 2002).

A 1:50,000 aeromagnetic survey of eastern Cuba was carried out to improve planning of mineral prospecting.

The aeromagnetic data were initially reduced to the pole. Horizontal gradients, vertical gradients and upward continuation were calculated and interpreted.

MATERIALS AND METHODS USED

The aeromagnetic data of eastern Cuba were measured along flight lines with north–south direction, separated each 500 m and to an average height of 70 m, with an error of ±10 nT (Chang et al., 1990, 1991).

A geological–geophysical interpretation was done by using all available geologic and tectonic information.

Eastern Cuba contains sequences of the Cuban folded belt and rocks of the "neoautochtonous" (Iturralde–Vinent, 1996a, b, c, 1998; Proenza, 1997; Proenza et al., 1999a). In the Mayarí and Sagua–Moa–Baracoa massif (Figure 1) oceanic outcrops correspond to the northern ophiolites, and to the Cretaceous and Paleogene volcanic island arcs plus some sedimentary formations (Cobiella, 1988, 1997, 2000; Quintas, 1989; Iturralde–Vinent, 1995, 1996a, b, c, 1998; Proenza, 1997, Proenza et al., 1999c).

The northern ophiolites are in the Mayarí–Baracoa ophiolitic belt (Iturralde–Vinent, 1994,1996a, 1998). Their main outcrop is represented by the Mayarí–Cristal and Moa–Baracoa massifs (Proenza, 1997; Proenza et al., 1999a). These ophiolites have been attributed to a backarc–marginal Sea system, located at the Cretaceous margin of the Bahamas Platform and the volcanic arc of the Greater Antilles Arc (Iturralde–Vinent, 1994, 1996a, 1998; Cobiella, 2000).

This ophiolitic belt constitutes an allochthonous pseudotabular body of ~170 km length. It exceeds 1000 m thickness (Iturralde–Vinent, 1996a, 1998). According to Fonseca et al. (1985, 1992), Iturralde–Vinent (1996a, 1998) and Proenza (1997), it contains different lithologies of a complete ophiolitic sequence, separated by tectonic contacts. The floor to roof sequence is composed of peridotites with tectonite textures, "ultramafic cumulate", mafic cumulate, diabase dikes and effusive–sedimentary rocks.

These ophiolites are structured in form of tectonic flakes, emplaced on volcano–sedimentary rocks of the Cretaceous island arc, which are covered transgressively by flyschoid sequences and olistostromes of Maastrichtian to Paleocene age (Mícara and La Picota formations). Occasional imbrications are observed between and under the ophiolites (Iturralde–Vinent, 1996a, b, 1998; Gyarmati et al., 1997; Cobiella, 2000).

The ophiolitic rocks are mainly covered by volcano–sedimentary materials of the Paleogene island arc and by younger terrigenous carbonate sequences (Quintas, 1989; Iturralde–Vinent, 1996a, b, 1998; Proenza, 1997; Cobiella, 1997, 2000).

Mayarí–Cristal ophiolitic massif

Mayarí–Cristal ophiolitic massif is located in the western part of the Mayarí–Baracoa ophiolitic belt, covering an estimated area of 1200 km² (Figure 1), with a thickness from 1 to 1.5 km according to Fonseca et al. (1985). This massif contains mainly ultramafic complex and diabase dikes; the existence of the gabbro complex is debated and the volcano–sedimentary one has not been described (Iturralde–Vinent, 1996a, 1998; Proenza, 1997, Proenza et al., 1999a; Cobiella, 2000).

The ultramafic rocks are predominantly constituted by harzburgites and dunites, and rarely by lherzolites and pyroxenites (Fonseca et al., 1985; Nekrasov et al., 1989; Navarrete and Rodríguez, 1991; Proenza et al., 1999a). Pyroxenite dikes also exist in the massif, cutting the peridotite and the chromitite bodies (Iturralde–Vinent, 1996a, 1998; Proenza, 1997; Proenza et al., 1999a; Cobiella, 2000).

The synthetic column of this massif (Figure 2) proposed by Proenza (1997) and Proenza et al. (1998b), contains from bottom to top: a) a harzburgite area with tectonite texture; b) an area of harzburgite alternation and dunite with abundant chromitite bodies and pyroxenite dikes (websterite); c) a possible area corresponding to the mafic cumulate (gabbro), which, if existing, should be extremely small; and d) the area of the diabase complex.

"La Corea melange" south of the massif (Figure 1), is an area of developing metamorphic rocks of about 25 km² (Adamovich and Chejovich, 1964; Millán, 1996). It is composed of blocks of metamorphic rocks separated by a serpentinitic matrix.

Moa–Baracoa ophiolitic massif

Moa–Baracoa ophiolitic massif is located at the end of the eastern Mayarí–Baracoa belt. It covers an approximate area of 1500 km² and it presents a considerable development of the ultramafic complex, of gabbro and volcano–sedimentary rocks (Proenza, 1997; Proenza et al., 1999a, b, c) (Figure 1). According to Fonseca et al. (1985) the approximate thickness of the ultramafic complex is 1000 meters and that of gabbro is 500 meters. Quintas (1989) estimates a thickness of 1200 meters for the volcano–sedimentary complex.

The ultramafic complex is characterized by harzburgites and by dunites to a lesser extent. Plagioclase dunites, wehrlites, lherzolites, and pyroxenites have also been described (García and Fonseca, 1994; Proenza et al., 1999a, b).

The gabbro cumulates form large bodies in the ultramafic complex. The dimensions of these bodies oscillate between 1 to 3 km wide, and 10 to 15 km long. The contact between the gabbro and the ultramafic complex is generally tectonic. Mainly the gabbro is covered by ultramafic rocks (Fonseca et al., 1985), although Andó et al. (1989) suggest that in some sectors the contact is of transitional type. The main gabbro types described are: olivine gabbros, gabbronorites, gabbros, anorthosites and norites (Ríos and Cobiella, 1984; Fonseca et al., 1985; Proenza, 1997; Proenza et al., 1999a, b; Rodríguez, 2000).

In the synthetic column of this massif (Figure 3), proposed by Proenza (1997) and Proenza et al. (1998b, 1999c), we have from bottom to top levels: a) a harzburgite area with tectonite textures; b) a harzburgite area that contains bodies of dunites, plagioclase dunites, gabbro sills, gabbro dike and pegmatitic gabbro; c) the area of gabbros, which present at the base great development of crossed gabbros (olivine gabbros, gabbronorites), grading upward into isotropic gabbros; d) the area of the complex of diabase dikes?, and e) the effusive–sedimentary complex.

The sequence of Cretaceous volcanic island arc fundamentally contains basaltic andesites and basalts, mainly tuffs and andesitic lava–breccia, dacites, tuffs, argillites, shales (volcanomictic), basaltic lavas (Cobiella, 2000; Campos and Hernández, 1987; Millán, 1996; Proenza and Carralero, 1994; Iturralde–Vinent, 1996c, 1998; Gyarmati et al., 1997).

According to Iturralde–Vinent (1994, 1996c), the basement of this volcanic arc is the oceanic crust of pre Aptian age, recognized in eastern Cuba as "Güira de Jauco" amphibolites.

In the contact of these Cretaceous rocks with the ophiolites, they are deformed and generally crushed to breccias. Sometimes the contacts coincide with cracked and foliated areas, or with chaotic masses that contain a mixture of ophiolite blocks and Cretaceous vulcanite (Iturralde–Vinent, 1996a, b, c, 1998; Cobiella, 2000).

The representative stratigraphic units of the Campanian Late–Danian are typically olistostromic sequences composed by fragments and blocks coming from the ophiolitic sequence and from the Cretaceous volcanic rocks (Cobiella, 1978a, b, 2000; Quintas, 1989, 1996). Brecciated limestones also appear, with volcanomictic conglomerate, breccia, marbles, tuffs, organo–detritic limestones, volcanomictic sandstones of calcareous cement, shales and tuffs (Iturralde–Vinent, 1976; Cobiella, 1978a, b; Quintas, 1989).

The sequences of the Paleogene volcanic islands arc are represented by vitroclastic–tuffs, litho–vitroclastic, vitroclastic–glass with intercalations of calcareous tuffs, tuffaceous sandstone, limestones, tuffaceous conglomerate, shales, marls, gravelites, volcanomictic conglomerate and some bodies of basalts, andesites, and andesites–basaltic, which attain 6000 m of thickness (Iturralde–Vinent, 1976, 1995, 1996b, 1998; Cobiella, 1988, 1997, 2000; Proenza and Carralero, 1994; Quintas et al., 1995).

The rocks associated to the Paleogene volcanic island arc are located on deformed materials of the Cretaceous arc, ophiolites and the sedimentary basins of the Campanian Late–Danian period (Proenza and Melgarejo, 1998).

Tectonic setting

The tectonics of the Cuban eastern block is characterized by a high complexity, due to the occurrence of events of different nature that have been superimposed in time and that have generated structures of varied intensity and indications at the surface (Rodríguez, 1998a, b). This block is characterized by the development of thrust tectonics that affects the oldest sequences (Campos, 1983).

Locally this complexity in the study region shows fundamentally faulting with northeast and northwest direction (Figure 1) that intersects and displaces each other (Campos, 1983; Rodríguez, 1998a, b). Dislocations of complex folding are also observed, mainly in the proximity of the tectonic contacts (Campos, 1983).

PETROPHYSIC CHARACTERIZATION

The study of the physical properties of rocks and minerals is important during the development of geologic and geophysical investigations. It helps select the geophysical methods to use and provides elements for the processing and interpretation of the geophysical data and allow geological and structural characterization of the region being investigated.

Several petrophysical works, aimed fundamentally to study the magnetic properties of the rocks, have been carried out on this region. Among the most significant works are those of Zamashikov and Tobachkov (1971) in the Moa–Baracoa massif, Chang et al. (1990, 1991) in the Mayarí–Sagua–Moa region, Rodríguez (1982) in the ultrabasic rocks of oriental Cuba, and Batista (2002) in the Moa region.

In this investigation, the measurements of the natural remanent magnetization from previous studies were not considered, due to the few samples analyzed, their locations and the obtained values of magnetization (Rodríguez, 1982).

The physical properties of rocks vary according to lithological changes, and even within a lithological type, depending on the degree of mineralization and alteration (Logachev and Zajarov, 1986). The study region is largely occupied by ophiolitic rocks and in smaller proportion by volcano–sedimentary, sedimentary and metamorphic rocks (Quintas, 1989; Iturralde–Vinent, 1996a).

The results of k measurements are noted in Table 1. Note that the igneous rocks possess the highest values in k, specifically the serpentinized ultrabasic rocks; thus the largest positive intensities in the magnetic field should be related to the geological and structural characteristics of such rocks, keeping in mind that they occupy most of the territory. In some small areas it can be caused by pyroxenites and diabases.

AEROMAGNETIC INTERPRETATION

Map of ΔT reduced to the pole (ΔTrp)

In the aeromagnetic survey of the region the intensities vary between –585 and 797 nT (Figure 4a). When reducing to the pole the map of ΔT (ΔTrp), the intensities oscillate from –456 to 1090 nT with means of 121 and –113 nT in the positive and negative values, respectively (Figure 4b).

In the map of ΔTrp the highest positive intensity value in the magnetic field are south of Sierra Cristal, while the negatives are located in the Pinares de Mayarí Plateau and its surroundings, and some locations between Sagua de Tánamo and Moa. Negative anomalies are related with areas of tectonic contact, suggesting that they may be caused by the decrease of magnetization in areas of tectonic weakness or by deeper rocks with smaller magnetization than the surrounding serpentinized rocks (Table 1). This has already been reported in some areas of this region (Campos, 1983; Murashko and Lavandero, 1989). Most of the outcrops of serpentinized peridotites are related to anomalies of high positive intensities and negatives, except to the south of the Pinares de Mayarí Plateau, where high negative intensities can be related to outcrops of Paleogene volcano–sedimentary rocks, at depths, or to other rocks of very low magnetization. We may dismiss serpentinized peridotites at depth, unlike the rest of the anomalies with high positive and negative intensities, where the serpentinized rocks prevail in surface and depth.

Where there is no presence of surface ophiolitic rocks, positive values of the magnetic field are registered, indicating the presence at depth, mainly of ultrabasic rocks (Zaigham and Mallick, 1994, 2000; Batista, 1998; Batista and Rodríguez, 2000; Chernicoff and Zapata, 1998).

High negative intensities of the magnetic field show near surface or outcropping rocks of very low magnetization and large thickness (Karlsen and Olesen, 1996; Batista, 1998; Batista and Rodríguez, 2000; Ghidella et al., 1998). In ultrabasic rocks these are either thin or are underlain by not very magnetic, probably volcano–sedimentary, sedimentary rocks or acid rocks that have not been reported previously in the area (Campos, 1983; Chang et al., 1990, 1991; Batista, 1998; Batista and Rodríguez, 2000). In a general way, if there are negative values where there is no outcrop of ultrabasic rocks, these do not extend laterally or don't possess a thickness able to be reflected in this magnetic field, or there are thick volcano–sedimentary and sedimentary rocks in the area, or carbonated rocks of the Bahamas paleomargin in depth, as reported in other regions of Cuba by Iturralde–Vinent (1994, 1996b) and Proenza and Melgarejo (1998).

These results suggest that it is possible to infer variations in thickness, as well as serpentinization levels of peridotites, from the behavior of the magnetic field. In the ophiolitic rocks the variations in thickness of the ophiolitic sect (cumulative or tectonites) are better defined (Iturralde–Vinent, 1996a; Proenza, 1997; Proenza et al., 1999a, b, c), which is important when prospecting for chromite deposits, since these deposits are usually inserted in dunites and harzburgites in the upper part of the basal tectonites of the ophiolitic sequences, including the so–called transition area (Nicolas and Prinzhofer, 1983; Proenza et al., 1998a, b, 1999a, b). Positive values of the magnetic field where there are outcrops of serpentinized peridotites or gabbros suggest thick tectonite layers, while negative values in gabbros indicate greater thickness of the cumulative section or a combination with other rocks underlying the low magnetization. Negative values in serpentinized rocks represent evidence of minimum thickness and the existence at depth of rocks of the cumulative level, volcano–sedimentary or both. In Cretaceous volcano–sedimentary rocks the negative values indicate a maximum thickness and an absence deep of serpentinitic rocks, while in the Paleogene volcano–sedimentary and the sedimentary rocks it suggest thickness, of the Cretaceous volcanic basement or of both rock groups. Finally positive values of the field in Cretaceous volcano–sedimentary outcrops indicate a maximum thickness that overlies the ultrabasic rocks, evidencing their allochthonous character.

The variations in thickness of the serpentinized ultrabasic rocks, according to the behavior of the magnetic field, is shown in Figure 5.

Over the lateritic deposits the magnetic field generally presents negative values, suggesting little thickness of serpentinitic bodies on which these deposits are developed (Karlsen and Olesen, 1996). They are usually found in outlying areas of the ophiolitic massif where a tectonic horst exists which has caused erosion of the most superficial lithology, or both conditions at the same time (Batista, 1998; Batista and Rodríguez, 2000).

Different areas of hydrothermal alteration are reported in the region (Ramayo, 2001, 2003; Rodríguez–Vega, 1998; Vila, 1999; Batista and Ramayo, 2000a, b). Here the magnetic field possesses negative intensities smaller than –25 nT and aligned anomalies related to fault systems (Figure 1). Such results agree with geophysical studies carried out previously in this region (Batista, 1998; Batista and Rodríguez, 2000). The importance of the delimitation of those areas resides in that they can be associated to secondary mineralization in precious metals. The presence of gold has been reported by Vila (1999) and Batista and Ramayo (2000a, 2000b). On the other hand, great damage may be caused to the metallurgical process by the presence of siliceous material in the laterites (Rojas and Beyris, 1994). These alterations also offer information on the regional tectonic and physical–chemical conditions in the interior and surroundings of the rocks (Utada, 1990).

Shaded relief maps of ΔTrp and horizontal gradients

In the contour and relief maps of ΔTrp (Figure 4 and 6) and of the horizontal gradients (Figure 7 and 8), we find anomalous areas with northeast and northwest direction, which could be related to the main fault systems in the region (Figure 1), in agreement with Naidu and Mathew (1998), in a different region of the world. The high gradients observed in areas of change of polarity of the magnetic field, suggest abrupt contacts between the geologic bodies. The aligned areas that show positive values of the field are indicative of an increment of magnetization, caused in ultrabasic rocks, by an increase of serpentinization or the existence at depth of serpentinitic peridotites, according to work carried out in the study region (Chang et al., 1990, 1991; Batista, 1998; Batista and Rodríguez, 2000; Batista et al., 2002) and in other parts of the world (Best et al., 1998; Goussev et al., 1998; Hassan et al., 1998; Peirce et al., 1998). In ophiolites and volcano–sedimentary rocks the negative values in the anomalous areas can be related to the existence of hydrothermal alterations (Utada, 1990; Locke et al., 1994; Alva–Valdivia et al., 1997; Batista, 1998; Batista and Rodríguez, 2000; Alva–Valdivia and Urrutia–Fucugauchi, 1998; Chernicoff and Paterlini, 1998) or of less magnetic rocks in the depth (Batista, 1998; Batista and Rodríguez, 2000).

Vertical gradient of ΔTrp

Figure 9 shows maps of the first and second vertical gradient of ΔTrp, in which appear different positive anomalies that reflect the existence of small and shallow geologic bodies with an appreciable magnetic behavior, which may provide information on shape, depth, extension, direction, etc. of the layers (Henderson, 1992; Best et al., 1998; Chernicoff and Zapata, 1998; Nash, 1998). In the higher order gradients those anomalies are accentuated, indicating the existence in surface of the bodies that produce them (Gunn et al., 1998). In the serpentinized peridotites we may observe many anomalies, some being elongated with northeast and northwest direction like the fault systems, others are found in areas of intersection of faults. These anomalies are due to an increment of serpentinization of the rocks (Chang et al., 1990, 1991; Logachev and Zajarov, 1986), in agreement with works carried out in other regions of the world (Nash, 1998). In other parts of the region the anomalies are linked to gabbros and volcanic rocks or the proximity of serpentinized rocks.

Maps of upward continuation of ΔTrp

Starting from the geologic features and the results of previous geophysical work in the region we find in the same outcrops, fundamentally ophiolitic rocks to depths that oscillate between 2 and 3 km according to Fonseca et al. (1985), Quintas (1989), Chang et al. (1990, 1991), Batista (1998) and Batista et al. (2002).

We select heights of 250, 500, 750, 1500, 1800, 2200 and 4000 meters (Figure 10) for an analysis of upward continuation.

When the recomputed elevation increases, the behavior of the magnetic field depends on the characteristics of the largest and deepest geologic bodies, that is to say, the effect of the superficial rocks is eliminated (Gunn et al., 1998). This transformation of the magnetic field has been used in numerous investigations with the objective of finding the deep structure of a region, as well as to separate the effect of different geologic objects of interest (Chang et al., 1990, 1991; Pearson, 1996; Best et al., 1998; Hassan et al., 1998; Zaigham and Mallick, 2000; Batista et al., 2002). In the study region initially the most important variations take place for the heights of 250, 500 and 750 m, which attenuate the small anomalies, of relatively shallow character and the effect of small bodies that produce them. In the case h = 250 m, the negative anomaly located to the northwest of the Pinares de Mayarí Plateau, is attributed to gabbros whose attenuation indicates depths of 250 m. In positive anomalies of serpentinized peridotites located to the southwest of Sierra Cristal and in the surroundings of Sagua de Tánamo and Moa town, this attenuation indicates that the thickness is less than 250 m except where anomalies with negative sign (north and south of Sagua de Tánamo town) in areas of serpentinized peridotites indicate the existence of a less magnetic lithology near the surface. Some investigators have suggested to the south of the Sagua–Moa region some ophiolites on volcanic rocks (Campos, 1983; Murashko and Lavandero, 1989). The bodies related to these anomalies possess depths around 250 m. For h = 500 m, the negative anomaly located northwest of Pinares de Mayarí Plateau in gabbros show the same depth. The attenuation of positive anomalies in Sierra Cristal and other areas in the surroundings of Moa and Sagua de Tánamo town, and on volcano–sedimentary rocks in this last town, suggests a depth of around 500 m for the serpentinized peridotites. The positive anomaly observed east of Moa town on serpentinized peridotites surrounded by gabbros confirm the results obtained from the map of ΔTrp, on a great depth of the gabbros and around 500 m depth of serpentinitic areas inside them. Finally, other anomalies are caused by bodies with larger depths around 750 m. The most significant are northeast and southwest of Sagua de Tánamo and Moa town, respectively, where volcano–sedimentary rocks outcrop in the first locality and serpentinized peridotites in the second. The last two areas are linked with a system of faults of northwest–southeast direction. Negative values are observed south of Sagua de Tánamo town, related to sedimentary rocks outcrop. For levels over 750 m no significant variations are observed until the interval 1500–1800 m, where the positive anomaly located on serpentinized rocks attenuates to the east of Mayarí town, suggesting a maximum depth of these rocks in this interval. At elevations of 2200 to 4000 m variations suggest that most of the peridotite bodies extending to such depths possess a metamorphic basement rich in magnetic minerals, as in other regions of the world (Logachev and Zajarov, 1986; Batista et al., 2002). The areas where the serpentinitic bodies are deeper or their magnetized metamorphic basement is closer to the surface, are located to the northwest of Pinares de Mayarí Plateau, in the Sierra Cristal, north of Sagua de Tánamo town, and south and southeast of Moa town where mountainous relief prevails with a combination of tectonic movements and erosion levels.

The areas of important negative values and of smaller thickness of the serpentinized peridotites and deeper rocks of low magnetization are located south of Sierra de Nipe.

RESULTS AND CONCLUSIONS

The aeromagnetic survey confirms the validity of the application of such surveys for areas of high geologic complexity in ophiolitic rocks.

Variations in thickness and lithology, of the two fundamental levels of the ophiolitic section defined the basement. Areas were also defined where the Cretaceous volcano–sedimentary rocks over on serpentinized peridotites. The high intensities of the magnetic field suggest that south of the Sierra Cristal the serpentinized rocks reach their maximum thickness or present a magnetic metamorphic basement near the surface. To corroborate this idea, detailed studies or deeper drilling in the region would be necessary. On lateritic deposits the magnetic field presents negative values, suggesting thin serpentinitic bodies in outlying areas of the ophiolitic massif or where a tectonic horst has caused the erosion of the cover. Lengthened anomalous areas, aligned anomalies and high gradients are reflected in the magnetic field.

Areas of probable hydrothermal alterations were defined, to assist in future prospecting for metals and exploitation of Fe+Ni laterites deposits. Tectonic windows were defined as well as sectors with increase of serpentinization along faults, and the proximity to the surface of ultrabasic rocks.

ACKNOWLEDGEMENTS

We thank the National Office of Mineral Resources of Cuba for facilitating access to the main geophysical survey carried out in the oriental region of Cuba; the direction of the Institute of Geology and Paleontology, particularly the Department of Geophysics, for facilitating the aeromagnetic data used in this work; the doctors José Rodríguez, Alina Rodríguez, Joaquín Proenza, Jesus Blanco, Antonio Rodríguez and Ramón González Caraballo, for suggestions that allowed to improve this work.

ADAMOVICH, A. and V. D. CHEJOVICH, 1964. Principales características de la geología y de los minerales útiles de la región nordeste de la provincia de Oriente. Revista Tecnológica, 2, 4–20.        [ Links ]

ALVA–VALDIVIA, L. M., D. J. DUNLOP and J. URRUTIA–FUCUGAUCHI, 1997. Rock magnetic properties of iron ores and host rocks from the Peña Colorada mining district, western Mexico. J. Appl. Geophys., 37, 2, 55–66.        [ Links ]

ALVA–VALDIVIA, L. M. and J. URRUTIA–FUCUGAUCHI, 1998. Rock magnetic properties and ore microscopy of the iron ore deposit of Las Truchas, Michoacán, Mexico. J. Appl. Geophys., 38, 4, 277–299.        [ Links ]

ALBEAR, J., I. BOYANOV, K. BREZSNYANSZKY, R. CABRERA, V. CHEJOVICH, B. ECHEVARRÍA, R. FLORES, F. FORMELL, G. FRANCO, I. HAYDUTOV, M. ITURRALDE–VINENT, I. KANTCHEV, I. KARTASHOV, V. KOSTADINOV, G. MILLÁN, R. MYCZYNSKI, E. NAGY, J. ORO, L. PEÑALVER, K. PIOTROWSKA, A. PSZCZOLKOWSKI, J. RADOCZJ, RUDNICKI and M.L. SOMIN, 1988. Mapa geológico de Cuba. Escala 1:250 000.        [ Links ]

ANDÓ, J., M. KOZÁK and Y. RÍOS, 1989. Caracterización general de la asociación ofiolítica de la zona Holguín–Moa y el papel de las ofiolitas en el desarrollo estructural de Cuba. Minería y Geología, 1, 15–33.        [ Links ]

BATISTA, J., 1998. Características geológicas y estructurales de la región de Moa a partir de la interpretación del levantamiento aeromagnético 1:50 000. MSc. Thesis, Institute Superior Mining Metallurgist of Moa, Cuba, 79 pp.        [ Links ]

BATISTA, J., 2002. Nuevas regularidades geológicas de la región Mayarí–Sagua–Moa a partir de la reinterpretación del levantamiento aerogeofísico 1:50 000. Dr. Thesis, Institute Superior Mining Metallurgist of Moa, Cuba, 115 pp.        [ Links ]

BATISTA, J. and L. RAMAYO, 2000a. Características aerogamma espectrométricas de las zonas de alteraciones hidrotermales de la región de Moa (Cuba oriental). In: V Congreso de Mineralogía y Metalogenia. Argentina (La Plata), 424–431.        [ Links ]

BATISTA, J. and L. RAMAYO, 2000b. Utilización de datos aerogamma espectrométricos para la localización de zonas de alteración hidrotermal en la región Sagua–Moa, Cuba oriental. Minería y Geología, 17, 3–4, 3–10.        [ Links ]

BATISTA, J. and A. RODRÍGUEZ, 2000. Particularidades geológicas del complejo ofiolítico de Moa a partir de los datos aeromagnéticos 1:50 000. Minería y Geología, 17, 1, 17–25.        [ Links ]

BATISTA, J., A. RODRÍGUEZ, J. BLANCO and J. PROENZA, 2002. Estructura del macizo ofiolítico de Moa (NE de Cuba) según la interpretación del levantamiento aeromagnético 1:50 000. Acta Geológica Hispánica, 37, 4, 369–387.        [ Links ]

BEST, M.E., H.J. ABERCROMBIE and J.W. PEIRCE, 1998. Faulting patterns in the Athabasca area of Alberta using high–resolution aeromagnetic data. Can. J. Explor. Geophys., 34, 1–2.        [ Links ]

CAMPOS, M., 1983. Rasgos principales de la tectónica de la porción oriental de Holguín y Guantánamo. Minería y Geología, 2, 51–76.        [ Links ]

CAMPOS, M. and M. HERNÁNDEZ, 1987. Acerca de la posible correlación de las metavulcanitas de la Sierra del Purial con las rocas de la asociación ofiolítica. Minería y Geología, 5, 2, 23–30.        [ Links ]

CHANG, J. L., G. GRIBNIOV and A. BRODOBOI, 1990. Informe sobre resultados del levantamiento aerogeofísico complejo en el territorio de las provincias de Santiago de Cuba, Holguín, Granma y Guantánamo (Sector Pinares de Mayarí). National office of Mineral Resources of Cuba, 314 pp.        [ Links ]

CHANG, J. L., L. CORBEA, F. PRIETO, J. HERNANDEZ D and G. BRITO, 1991. Informe sobre los resultados del levantamiento aerogeofísico complejo en el territorio de las provincias Guantánamo y Holguín (Sector Guantánamo sur). National office of Mineral Resources of Cuba, 260 pp.        [ Links ]

CHARBONNEAU, B. W. and M. I. LEGAULT, 1994. Interpretation of airborne geophysical data for the Lake Area, northwest territories. In: Studies of rare–metal deposits in the northwest territories, (ed.) W.D. Sinclair and D.G Richardson; Geological Survey of Canada Bulletin 475, 17–31.        [ Links ]

CHERNICOFF, C. J. and C. M. PATERLINI, 1998. Interpretación geológica de la anomalía magnética del Departamento Mártires, provincia del Chubut (Argentina). In: X Congreso Latinoamericano de Geología y VI Congreso Nacional de geología económica. Simposio: Geofísica aérea y geoquímica en la prospección geológica–minera, 31–42.        [ Links ]

CHERNICOFF, C. J. and M. C. ZAPATA, 1998. Estudio preliminar de interpretación geológica del levantamiento aeromagnético del área Las Petas, república de Bolivia. In: X Congreso Latinoamericano de Geología y VI Congreso Nacional de geología económica. Simposio: Geofísica aérea y geoquímica en la prospección geológica–minera, 81–85.        [ Links ]

CLARK, D. A., 1997. Magnetic petrophysics and magnetic petrology: aids geological interpretation of magnetic surveys. AGSO J. Aust. Geol. Geophys., 17, 2, 83–104.        [ Links ]

COBIELLA, J. L., 1978a. Estratigrafía y paleogeografía del Paleógeno de Cuba oriental. Dr. Thesis, Institute Superior Mining Metallurgist of Moa, Cuba, 210 pp.        [ Links ]

COBIELLA, J. L., 1978b. Un melange en Cuba oriental. La Minería en Cuba, 4, 4, 4–51.        [ Links ]

COBIELLA, J. L., 1988. El vulcanismo paleogénico cubano. Apuntes para un nuevo enfoque. Rev. Tecnol., 18, 4, 25–32.        [ Links ]

COBIELLA, J. L., 1997. Zonación estructuro facial del corte Paleoceno Eoceno Medio de Cuba. Minería y Geología, 14, 1, 3–12.        [ Links ]

COBIELLA, J. L., 2000. Jurassic and Cretaceous geological history of Cuba. Inter. Geol. Rev., 42, 594–616.        [ Links ]

CORNER, B. and W. A. WILSHER, 1989. Structure of the Witwatersrand Basin Derived from Interpretation of Aeromagnetic and Gravity Data. Proceedings of Exploration '87, Ontario Geological Survey, Special Volume 3, 532–546.        [ Links ]

FINN, C., PILKINGTON, M., CUEVAS, A. and J. URRUTIA FUCUGAUCHI, 2001a. New digital data base helps to map North America. EOS, Trans. Am. Geophys. Union, 82, 30, 325–330.        [ Links ]

FINN, C., PILKINGTON, M., CUEVAS, A. and J. URRUTIA FUCUGAUCHI, 2001b. New digital magnetic anomaly data base for North America. The Leading Edge, 20, 870–872.        [ Links ]

FONSECA, E., V. SLADKEVICH, M. SANTA CRUZ, A. MORALES, R. RODRÍGUEZ, C. CAPOTE, M. NAVARRETE and I. GARCÍA, 1992. Geología de los yacimientos cromíticos con evaluación pronóstico. Informe final tema 401–12. Unidad Minera Punta Gorda, Moa, Cuba, 127 pp.        [ Links ]

FONSECA, E., V. N. ZELEPUGIN and M. HEREDIA, 1985. Structure of the ophiolite association of Cuba. Geotectonic, 19, 321–329.        [ Links ]

GARCÍA, J. L., 1999. Interpretación del vuelo magnético y radiométrico de la faja pirítica en las hojas A E. 1/25 000, No. 959–I Villanueva de las Cruces y 960–II Berrocal. Bol. Geol. y Min., 10, 3, 31–47.        [ Links ]

GARCÍA, I. and E. FONSECA, 1994. La mineralización cromítica y su relación con las cloritas en el yacimiento Amores. Minería y Geología, 11, 50–54.        [ Links ]

GHIDELLA, M. E., J. L. LABRECQUE and G. A. RODRÍGUEZ, 1998. Los movimientos de la península Antártica en el mesozoico. In: X Congreso Latinoamericano de Geología y VI Congreso Nacional de geología económica. Simposio: Geofísica aérea y geoquímica en la prospección geológica–minera, 59–79.        [ Links ]

GOUSSEV, S. A., R. A. CHARTERS, H. H. HASSAN, J. H. PEIRCE and J. A. GENEREUX. HRAM fault interpretation using MAGPROBE depth estimates and non–traditional filtering. Can. J. Expl. Geophys., 34, 1 and 2, 30–39.        [ Links ]

GUNN, P. J., T. MACKEY and T. J. MEIXNER, 1998. Magnetic, radiometric and gravity signatures of localities of epithermal gold deposits in Fiji. In: X Congreso Latinoamericano de Geología y VI Congreso Nacional de geología económica. Simposio: Geofísica aérea y geoquímica en la prospección geológica–minera, 43–51.        [ Links ]

GYARMATI, P., I. MENDEZ D and M. LAY, 1997. Caracterización de las rocas del arco de islas Cretácico en la Zona Estructuro–Facial Nipe–Cristal–Baracoa. In: G. F. Furrazola, K. E. Núñez–Cambra (eds.). Estudios sobre Geología de Cuba, Ciudad de la Habana, Instituto de Geología y Paleontología, 357–364.        [ Links ]

HASSAN, H. H., J. W. PEIRCE, W. C. PEARSON and J. M. PEARSON, 1998. Cultural editing of HRAM data comparison of techniques. Can. J. Expl. Geophys., 34, 1 and 2, 16–22.        [ Links ]

HENDERSON, R. J., 1992. Urban geophysics – a review. Expl. Geophys., 23, 531–542.        [ Links ]

ISHIHARA, S., 1990. The inner zone batholith vs. the outer zone batholith of Japan: evaluation from their magnetic susceptibilities. In: University Museum Tokyo, nature and culture. 2, 21–34.        [ Links ]

ITURRALDE–VINENT, M. A., 1976. Estratigrafía de la zona Calabazas–Achotal, Mayarí Arriba. Oriente. La Minería en Cuba, 5, 9–23.        [ Links ]

ITURRALDE–VINENT, M. A., 1989. Role of ophiolites in the geological constitution of Cuba. Geotectonics, 4, 63–74.        [ Links ]

ITURRALDE–VINENT, M. A., 1994. Cuba Geology: a new plate–tectonic synthesis. J. Petrol. Geol., 17, 39–70.        [ Links ]

ITURRALDE–VINENT, M. A., 1995. El segmento cubano del arco volcánico paleoceno–eoceno medio del Caribe. In: A. Ali y P.V. Young (Eds), Transaction of the 3^rd Geological Conference of the Geological Society of T&T, 1, 343–362.        [ Links ]

ITURRALDE–VINENT, M. A., 1996a. Geología de las ofiolitas de Cuba. In: Iturralde–Vinent, M. (ed.). Ofiolitas y arcos volcánicos de Cuba. IGCP project 364. Special contribution n. 1, 83–120.        [ Links ]

ITURRALDE–VINENT, M. A., 1996b. Introduction to Cuban Geology and Tectonics. In: Iturralde–Vinent, M. (ed.). Ofiolitas y arcos volcánicos de Cuba. IGCP project 364. Special contribution n.1, 3–35.        [ Links ]

ITURRALDE–VINENT, M. A., 1996c. Cuba: el arco de islas volcánicas del Cretácico. In: M. Iturralde–Vinent (ed.). Ofiolitas y arcos volcánicos de Cuba. IGCP project 364. 179–189.        [ Links ]

ITURRALDE–VINENT, M.A., 1998. Sinopsis de la constitución geológica de Cuba. Acta Geológica Hispana, 33, 1–4, 9–56.        [ Links ]

KARLSEN, T. A. and O. OLESEN, 1996. Airborne geophysical prospecting for ultramafite associated talc, Altermark, northern Norway. J. Appl. Geophys., 35, 4, 215–236.        [ Links ]

KNIPPER, A. and R. CABRERA, 1974. Tectónica y geología histórica de la zona de articulación entre el mio y el eugeosinclinal de Cuba y del cinturón hiperbasítico de Cuba. En: Contribución a la geología de Cuba, Academia de Ciencias de Cuba, 15–77.        [ Links ]

LAGROIX, F. and G. J. BORRADAILE, 2000. Tectonics of the circum–Troodos sedimentary cover of Cyprus, from rock magnetic and structural observations. J. Struct. Geol., 22, 4, 453–469.        [ Links ]

LAVAUT, W., 1998. Tendencias geológicas del intemperismo de las rocas ultramáficas en Cuba oriental. Minería y Geología, 15, 9–16.        [ Links ]

LOCKE, C. A., J. CASSIDY and A. MACDONALD, 1994. Contraints on the evolution of the Taranaki volcanoes, New Zealand, based on aeromagnetic data. Bull. Volcanol., Abstr., 56, 6/7, 552–560.        [ Links ]

LOGACHEV, A. A. and V. P. ZAJAROV, 1986. Exploración magnética. 4ta edición. Barcelona: Editorial Reverté S.A. Encarnación, 346 pp.        [ Links ]

MICKUS, K. L. and B. DURRANI, 1996. Gravity and magnetic study of the crustal structure of the San Francisco volcanic field, Arizona, USA. Tectonophys., 267, 1–4, 73–90.        [ Links ]

MILLÁN, G., 1996. Metamorfitas de la Asociación Ofiolítica de Cuba. En: Iturralde–Vinent, M.A. ed., Ofiolitas y arcos volcánicos de Cuba. IGCP Project 364. Special Contribution n. 1, 131–153.        [ Links ]

MIRANDA, F. P., A. E. MCCAFFERTY and J. V. TARANIK, 1994. Reconnaissance geologic mapping of a portion of the rain forest covered Guiana Shield, northwestern Brazil, using SIR–B and digital aeromagnetic data. Geophys., 59, 733–743.        [ Links ]

MURASHKO, V. I. and R. M. LAVANDERO, 1989. Chromite in the hyperbasite belt of Cuba. International Geology Review, 31, 90–99.        [ Links ]

NAIDU, P.S. and M.P. MATHEW, 1998. Digital analysis of aeromagnetic maps: detection of a fault. J. Appl. Geophys., 38, 3, 169–179.        [ Links ]

NASH, C. R., 1998. Lithostructural interpretation of imaged shallow–source aeromagnetic data. In: X Congreso Latinoamericano de Geología y VI Congreso Nacional de geología económica. Simposio: Geofísica aérea y geoquímica en la prospección geológica–minera, 87–111.        [ Links ]

NASH, C. R. and C. J. CHERNICOFF, 1998. Integrated interpretation of reconnaissance aeromagnetic and Landsat TM data, precordillera region, northwest Argentina. In: X Congreso Latinoamericano de Geología y VI Congreso Nacional de geología económica. Simposio: Geofísica aérea y geoquímica en la prospección geológica–minera, 21–29.        [ Links ]

NAVARRETE, M. and R. RODRÍGUEZ, 1991. Generalización petrológica del corte ofiolítico de los yacimientos de Pinares de Mayarí, Canadá y Luz Norte, Macizo Mayarí–Nícaro. Minería y Geología, 8, 3–10.        [ Links ]

NEKRASOV, G., J. ORO, S. D. SOKOLOV, R. FLORES and M. V. SHAVYRINA, 1989. Ophiolites of Eastern Cuba. Geotectonic, 23, 60–71.        [ Links ]

NICOLAS, A. and A. PRINZHOFER, 1983. Cumulative or residual origin for the transition zone in ophiolites: structural evidence. J. Petrol., 24, 188–206.        [ Links ]

PAPAYANNOPOULOU–ECONONOMOU, A. and A. D. KISKYRAS, 1981. Some remarks on the application of the geophysical prospecting for chromites and Ni–Fe laterite deposits. In: UNESCO. An international symposium on metallogeny of mafic and ultramafic complexes: The eastern Mediterranean–western Asia area, and its comparison with similar metallogenic environments in the world. 1, 102–113.        [ Links ]

PEARSON, A. W. C., 1996. Removing culture from southern Texas – a magnetic cleanup and image revolution. Expanded Abstrcts with Biographies, SEG International Exposition and 66^th Ann. Mtg., Denver, 1407–1410.        [ Links ]

PEIRCE, J. W., H. J. ABERCROMBIE, G. R. DEPAOLI, S. A. GOUSSEV and R. A. CHARTES, 1998. Intra–sedimentary magnetization by vertical fluid flow and exotic geochemistry. The leading Edge, 89–92.        [ Links ]

PROENZA, F. J., 1997. Mineralización de cromita en la faja ofiolítica Mayarí–Baracoa (Cuba): Ejemplo del yacimiento Mercedita. Dr. Thesis. University of Barcelona, 227 pp.        [ Links ]

PROENZA, J. and N. M. CARRALERO, 1994. Un nuevo enfoque sobre la geología de la parte sur de la cuenca de Sagua de Tánamo. Minería y Geología, 11, 3–10.        [ Links ]

PROENZA, J., F. GERVILLA, J. C. MELGAREJO, D. REVÉ and G. RODRÍGUEZ, 1998a. Las cromititas ofiolíticas del yacimiento Mercedita (Cuba). Un ejemplo de cromitas ricas en Al en la zona de transición manto–corteza. Acta Geol. Hispán., 33, 1–4, 179–212.        [ Links ]

PROENZA, J. and J. C. MELGAREJO, 1998. Una introducción a la metalogenia de Cuba bajo la perspectiva de la tectónica de placas. Acta Geol. Hispán., 33, 1–4, 89–131.        [ Links ]

PROENZA, J. A., J. C. MELGAREJO, F. GERVILLA, W. LAVAUT, D. REVÉ and G. RODRÍGUEZ, 1998b. Cromititas podiformes en la Faja Ofiolítica Mayarí–Baracoa (Cuba). In: J. C. Melgarejo y J. A. Proenza (eds.). Geología y Metalogenia de Cuba: Una Introducción. Acta Geol. Hispán., 33, 1–4, 153–177.        [ Links ]

PROENZA, J., F. GERVILLA, J. C. MELGAREJO and J. L. BODINIER, 1999a. Al– and Cr–rich chromitites from the Mayarí–Baracoa ophiolitic belt (Eastern Cuba): Consequence of interaction between volatile–rich melts and peridotites in suprasubduction mantle. Econ. Geol., 94, 547–566.        [ Links ]

PROENZA, J., F. GERVILLA and J. C. MELGAREJO, 1999b. La Moho Transition Zone en el Macizo Ofiolítico Moa–Baracoa: un ejemplo de interacción magma/ peridotita. Rev. Soc. Geol. España, 12, 3–4, 309–327.        [ Links ]

PROENZA, J., J. C. MELGAREJO, F. GERVILLA and J. SOLÉ, 1999c. Los niveles de gabbros bandeados en el macizo ofiolítico Moa–Baracoa (Cuba). Gabbros característicos de cumulados de ofiolitas de zonas de suprasubducción. Minería y Geología, 16, 2, 5–12.        [ Links ]

QUINTAS, F., 1989. Análisis estratigráfico y paleogeografía del Cretácico Superior y del Paleógeno de la provincia Guantánamo y áreas cercanas. Dr. Thesis, Institute Superior Mining Metallurgist of Moa, Cuba, 161 pp.        [ Links ]

QUINTAS, F., 1996. Bioestratigrafía del corte Meso–Cenozoico del extremo oriental de Cuba. Minería y Geología, 13, 1, 3–8.        [ Links ]

QUINTAS, F., J. PROENZA and J. L. CASTILLO, 1995. Análisis tectono–sedimentario de la paleocuenca Sabaneta. Minería y Geología, 12, 3–8.        [ Links ]

RAMAYO, L., 2001. Texturas de cuarzo y sus agregados del sistema epitermal El Rifle–Hato Viejo. Descripción e implicancias genéticas. Minería y Geología, 18, 3–4, 3–12.        [ Links ]

RAMAYO, L., 2003. Geoquímica y mineralogía de la mineralización epitermal de la región nororiental de la provincia Holguín. En los ejemplos de las manifestaciones minerales Hato Viejo y El Rifle–Los Calderos. Dr. Thesis, Institute Superior Mining Metallurgist of Moa, Cuba, 104 pp.        [ Links ]

RÍOS, Y. I. and J. L. COBIELLA, 1984. Estudio preliminar del macizo de gabbroides Quesigua de las ofiolitas del este de la provincia de Holguín. Minería y Geología, 2, 109–132.        [ Links ]

RODRÍGUEZ, A., 1998a. Estudio morfotectónico de Moa y áreas adyacentes para la evaluación de riesgo de génesis tectónica. Dr. Thesis, Institute Superior Mining Metallurgist of Moa, Cuba, 124 pp.        [ Links ]

RODRÍGUEZ, A., 1998b. Estilo tectónico y geodinámico de la región de Moa. Minería y Geología, 15, 2, 37–41.        [ Links ]

RODRÍGUEZ–VEGA, A., 1998. Epitermalismo en la región de Sagua–Moa–Baracoa. Conferencia Internacional de Aprovechamiento Racional de los Recursos Minerales. Libro de resúmenes CINAREM 98, p12.        [ Links ]

RODRÍGUEZ, J., 1982. Estructura geológica profunda de Cuba oriental en base a datos geofísicos. Dr. Thesis. Institute of Mines of Leningrado. 246 pp.        [ Links ]

RODRÍGUEZ, R., 2000. Estudio petrológico de las rocas de afinidad ofiolítica portadoras de ilmenita en la zona de Cayo Grande en el macizo Moa–Baracoa. MSc. Thesis, Institute Superior Mining Metallurgist of Moa, Cuba, 69 pp.        [ Links ]

ROJAS, A. and P. BEYRIS, 1994. Influencia de la composición mineralógica del material limonítico de frentes de explotación de la industria Pedro Soto Alba, Moa. Minería y Geología 11, 1, 13–17.        [ Links ]

SHAPIRO, V. A., N. V. FEDOROVA, F. I. NIKONOVA, A. V. CHURSIN, Y. P. MENSHIKOV and G. S. KIMBELL, 1997. Preliminary investigation of the crustal structure of the southern Urals by geomagnetic methods. Tectonophys., 276, 1–4, 35–47.        [ Links ]

SINTUBIN, M., 1999. Arcuate fold and cleavage patterns in the southeastern part of the Anglo–Brabant Fold Belt (Belgium): tectonic implications. Tectonophys., 309, 1–4, 81–87.        [ Links ]

THAYER, T. P., 1942. Chrome resources of Cuba. U.S. Geol. Survey Bull., 93–A, 1–74.        [ Links ]

UTADA, M., 1990. Preliminary note on hydrothermal alteration appearing in the Inbi complex of cretaceous to paleogene age. In: University Museum Tokyo, nature and culture. 2, 67–76.        [ Links ]

VILA, A., 1999. Principales rasgos de la distribución del oro en los depósitos exógenos de la región Sagua–Moa. MSc. Thesis, Institute Superior Mining Metallurgist of Moa, Cuba, 76 pp.        [ Links ]

ZAIGHAM, N. A. and K. A. MALLICK, 1994. Subsurface continuation of the ophiolites in the Bela Plain of Balochistan, Pakistan. Ofioliti, 19, 269–278.        [ Links ]

ZAIGHAM, N. A. and K. A. MALLICK, 2000. Bela ophiolite zone of southern Pakistan: Tectonic setting and associated mineral deposits. GSA Bulletin, 112, 3, 478–489.        [ Links ]

ZAMASHIKOV, M. E. and V. TOBACHKOV, 1971. Informe sobre los resultados de los trabajos de búsqueda a escala 1:50 000 en la parte suroeste del macizo hiperbasítico Moa – Baracoa. National office of Mineral Resources of Cuba.        [ Links ] ]]> 1964 2 2 4-20 1997 37 2 2 55-66 1998 38 4 4 277-299 1988 1989 1 1 15-33 1998 79 2002 115 2000 a (La Plata) 424-431 2000 b 17 3-4 3-4 3-10 2000 17 1 1 17-25 2002 37 4 4 369-387 1998 34 34 1-2 1983 2 51-76 1987 5 2 2 23-30 1990 314 1991 260 1994 475 17-31 1998 31-42 1998 81-85 1997 17 2 2 83-104 210 1978 b 4 4 4 4-51 1988 18 4 4 25-32 1997 14 1 1 3-12 2000 42 42 594-616 1989 3 532-546 2001 a 82 30 30 325-330 2001 b. 20 20 870-872 1992 127 1985 19 19 321-329 1999 10 3 3 31-47 1994 11 11 50-54 1998 59-79 34 1 and 2 1 and 2 30-39 1998 43-51 1997 357-364 1998 34 1 and 2 1 and 2 16-22 1992 23 23 531-542 1990 2 21-34 1976 5 5 9-23 1989 4 4 63-74 1994 17 17 39-70 1995 1 343-362 1996 a 1 83-120 1996 b 1 3-35 1996 c 179-189 1998 33 1-4 1-4 9-56 1996 35 4 4 215-236 1974 15-77 2000 22 4 4 453-469 1998 15 15 9-16 1994 56 6/7 6/7 552-560 1986 4 346 1996 267 1-4 1-4 73-90 1996 1 131-153 1994 59 59 733-743 1989 31 31 90-99 1998 38 3 3 169-179 1998 87-111 1998 21-29 1991 8 8 3-10 1989 23 23 60-71 1983 24 24 188-206 UNESCO 1981 1 102-113 1996 Denver 1407-1410 1998 89-92 1997 227 1994 11 11 3-10 1998 a 33 1-4 1-4 179-212 1998 33 1-4 1-4 89-131 1998 b 33 153-177 1999 a 94 94 547-566 1999 b 12 3-4 3-4 309-327 1999 c 16 2 2 5-12 1989 161 1996 13 1 1 3-8 1995 12 12 3-8 2001 18 3-4 3-4 3-12 2003 104 1984 2 2 109-132 1998 a 124 1998 b 15 2 2 37-41 1998 12 1982 246 2000 69 1994 11 1 1 13-17 1997 276 1-4 1-4 5-47 1999 309 1-4 1-4 81-87 1942 93-A 1-74 1990 2 67-76 1999 76 1994 19 19 269-278 2000 112 3 3 478-489 1971