Martín Izard, A. (1986): Las mineralizaciones uraníferas del CEG en la provincia de Salamanca. Stvdia Geologica Salmanticensia, 23: 7-59.
ABSTRACT: The main stratigraphic, tectonic and metamorphic features of the uraniferous mineralizations hosted into de metasediments located in the west of the Salamanca province, are described in this paper. Special emphasis is made on the mineralogical and structural nature of de regional radioactive anomalies and deposits.
González Delgado, J.A. (1986): Estudio sistemático de los gasterópodos del Plioceno de Huelva (SW de España), II: Mesogastropoda (Rissoacea, Cerithiacea). Stvdia Geologica Salmanticensia, 23: 61-120.
ABSTRACT: The present work describes and discusses 18 species of Rissoacea and Cerithiacea from different pliocene outcrops (Upper Tabianian) from the Province of Huelva (SW of Spain). Also presented are their abundance, chronostratigraphic, bathymetric and geographic distribution together with the substrate type, nutrients and recent citations in the spanish Pliocene
Sierro, F.J. (1986): Estudio sistemático de los foraminíferos planctónicos del Neógeno de la Cuenca del Gualdalquivir: Género Globorotalia. Stvdia Geologica Salmanticensia, 23: 121-169.
ABSTRACT: The observed variations in the relative abundance of various species of Globorotalia, one of the most representative for the Neogene sediments in the Guadalquivir basin, are the basis for our biostratigraphic and paleoecological studies. A detailed description of ten species of Globorotalia is given in this paper along with a discussion of the relationship and differences among them.
Martín Izard, A., Palero Fernández, F.J., Reguilón Bragado, R. & Vindel Catena, E. (1986): El skarn de Carracedo (San Salvador de Cantamuda). Un ejemplo de mineralización pirometasomática en el N. de la provincia de Palencia. Stvdia Geologica Salmanticensia, 23: 171-192.
ABSTRACT: The existence of several worked out skarn ore bodies sourrounding some small stocks outcropping in the north of the Palencia province in the Cantabric Cordillera (Spain) has a great metallogenic interest due to the lack of this kind of mineralization in the area.
The country rocks consist of a Paleozoic sequence made up mainly of carbonates and pelites ending with the Carboniferous Brañosera formation wich hosts the ore deposits. Marbles and hornfelnes form the skarn at the contact between the sedimentary rocks and the dioritic intrusives. The marbles are made up mainly of calcite and some dolomite, while the hornfelnes show a mineralogical association made up of garnet, anphibol, pyroxene and epidote. In general, the host rocks are strongly altered ith development of abundant tourmaline, chlorite, sericite and silica.
In these pyrometasomathic deposits, chalcopirite, arsenopirite and magnetite and occasionally sphalerite, freibergite, pirrotite and gold, are the main components of the ore.
Franco González, M.P. & García de Figuerola, L.C. (1986): Las rocas básicas y ultrabásicas en el extremo occidental de la Sierra de Ávila (provincias de Ávila y Salamanca). Stvdia Geologica Salmanticensia, 23: 193-218.
ABSTRACT: Twenty five outcrops of basic rocks located in the part of the province of Avila and the S.E part of the province of Salamanca are described. Some of them have received attention in previaus studies. P. Franco (1980) and the Department of Petrology and Geochemistry at Salamanca University (1980), included them in the "Appinitic" suite as genetically independent of the surrouding granitoids. They may intrude into the medium to high grade regional metamorphism, though more commonly they intrude in contact with or are within the "late granodiorite" whose characteristics correspond to the "Jüngerer porphyrischer Granit" of Schmidt-Thome (1945) and which are considered by us as S type and as the Ilmenite suite.
The most probable hypothesis concerning heir origin is that they evolved from large subjacent masses of mantle to a large extent responsible for the regional metamorphism and for originating and induced anatexis giving rise to granitoids partially uprroted from thc anatectic zones, englobing during their ascent some of the basic and ultrabasic outcrops.
The authors believe that the ascent of these small masses took place immediately prior (or almost simultaneously) to the development of migmatization and hence predate the ascent of the granitoids.
Flores Villarejo, J.-A. (1986): Estudio sistemático de los asterolitos del sector NO de la cuenca del Guadalquivir (SO de España) y sondeos oceánicos D.S.D.P. próximos. I. Stvdia Geologica Salmanticensia, 23: 219-263.
ABSTRACT: The present work describes and comments on 11 species of asteroliths recorded in the Guadalquivir Basin and adjacent D.S.D.P. sites; the species belong to the groups Eu discoaster quinqueramus, Eu discoaster brouweri and Eu discoaster pentaradiatus, and were found together with other species which cannot be adscribed to these or other groups; such species will be described in later works. A series of comments regarding the conservational status and paleoecological aspects of the species discussed is provided.
The sediments where the species are found cover an interval in the Tortonian Lower Pliocene.
Palero, F.J. (1986): El campo filoniano de El Hoyo de Mestanza (Ciudad Real). Sobre el origen de las mineralizaciones B.G.P.C. asociadas con zonas de cizalla. Stvdia Geologica Salmanticensia, 23: 265-297.
ABSTRACT: The ore deposits in the Hoyo de Mestanza, placed in a traditional mine area, consists of a group of quartz veins composed of sphalerite, galena, pyrite and chalcopyrite. These veins take an unchanging direction, the WNW ESE one which coincides with the main hercynian direction. They fit together irregularly on the monotonous series of the later Precambric called the "Alcudiense".
The veins in the Hoyo show some peculiar characteristics that make them different from other deposits in the same area. They are not just quartz dykes with sulphides, but parts of the rock that have borne an intense cataclasis, mylonitization and silicification and whith very often present a chaotic and fluid like appearance, boudinaje and also very irregular and little pronounced contacts.
These bodies are perfectly controlled by the litological and structural characteristic of the Estratos Pochico formation and are precisely located on the thick cuarcita Armoricana. And indeed, it is so strong a control that mineralised bodies vanish immediately when they get into the lower or upper formations.
According to field work and laboratory research, we can state that these ore bodies were formed and tectonised during the first phase of the hercinian deformation, the most important one in this area, and also the reason why these deposits cannot be related to the granitic intrusions in Sierra Morena (as it had been assumed so far) for they are later than the above mentioned phase.
Another thing to be borne in mind, is that the El Hoyo de Mestanza veins are always located in inverted faults connected with the most compact folds of the Estratos Pochico, because of that, this study intends to explain a genetic model that proves that these veins formation in caused by the filling of tension gashes associated with shears zones, that are not in a clearly paralel position in relation to the folds axial plane, so according to a continous proccess these fractures changed their ductility (mere f1exion) into fragility (inverted fault).
Cembranos Pérez, Mª.L. (1986): Características químicas y mineralógicas de suelos desarrollados sobre material básico del gran dique de Alentejo-Plasencia. Stvdia Geologica Salmanticensia, 23: 299.312.
ABSTRACT: The main chemical and mineralogical features of five soils developed on basics rocks in the big dike of Alentejo Plasencia, in two differents areas (NE and SW extremes) are described in this paper. The soils are lightly acid, with balancing textures and moderate rich in organic matter. The saturation is in agreement with the pH, wich is higher than 50%; and with large liberation of free iron and aluminium oxides, but the content in free silice is low.
The sand is poor in heavy fraction, with a middle value of 13%, and the mineralogical association in this fraction is: pyroxenes magnetite epidote. In the clay fraction the essentials components are Illite and Kaolinite.
Jiménez Fuentes, E., Acosta, P., Fincias, B. & Martín de Jesús, S. (1986): Un nuevo ejemplar de tortuga gigante del Mioceno de Arévalo (Ávila). Stvdia Geologica Salmanticensia, 23: 313-324.
ABSTRACT: A new specimen of giant turtle from Miocene deposits (Lower Vallesian) in Arévalo (Avila territory, Castilla, Central Spain) is described. It is determined as an adult male of Cheirogaster s.l. richardi (Bergounioux 1938; emend. Jimenez 1984).
Armenteros Armenteros, I. (1986): Evolución paleogeográfica miocena en el sureste de la depresión del Duero. Stvdia Geologica Salmanticensia, 23: 325-337.
ABSTRACT: The evolution of sedimentary environment during the Middle and Upper Miocene times at the southeastern region of the Duero Basin is dominated by the interrelation in space and time of three groups of facies: ALLUVIAL FANS attached to the mountainous Honrubia socle. FLUVIATILE placed just northwards from the former and LACUSTRINE PALUDAL made up of carbonate sediments and placed at the edges of the two former facies.
The analysis of the distribution of facies leads to the distinction of three paleogeographic situations considered as end members and intermediate stages. Stage A shows the maximum extent of the alluvial and fluviatile realms related to the paleoreliefs placed toward the south and east respectively. Stage B represents the implantation of a lacustrinc realm between the coalescent alluvial fans and the fluvial system that, consequently, is displaced towards the north. Stage C represents the maximum extension of the lacustrine realms that onlap the adjacent ones.
These different models result from the variations of the balance between the surrection of the edges of the basin and the subsidence of the basin. Additional effects result from climatic gradients, affecting the erosional, depositional and postsedimentary processes.