ORIGIN OF LIFE ON EARTH: SELF-ORGANIZING VESICLE-LIKE STRUCTURES IN CORDIERITE-ROCKS FROM SOTO (ARGENTINA)
Abstract: At Orcoyana, in the Soto region (Argentina), two types of cordieritic rocks outcrop: a light variety and a dark variety. Both of these contain, in very different quantities, very peculiar structures considered in literature as porphyroblasts. In order to gain insight into their origin, a petrologic and geochemical study was carried out. In the light of the new ordering principle, called "order through fluctuation", we applied the basic principles of self-organization dynamics to the Argentine structures. They appear to have "self-organized" as colloidal dissipative structures which formed in a self-organizing basic fluid. According to us, the origin of the Argentine structures involved a phase separation process ensuing from spontaneous density fluctuations in critical conditions. As the phase separation proceeded the fluid comprised immiscible portions in a state of emulsion. When the segregated phase was very concentrated, the Argentine fluid exhibited three distinguishable phases. From a thermodynamic point of view, there was a three-phase system, like a vesicle, with an interior, barrier and exterior.
VOURINOS COMPLEX (GREECE) — AN EXAMPLE OF EASTERN MEDITERRANEAN OPHIOLITE
Abstract: The Vourinos Ophiolite Complex, (northern Greece) of Jurassic emplacement, is one of the most intensively studied Mediterranean ophiolites. A highly depleted upper mantle of harzburgite character (in the basal section represented by "basal serpentinites") was generated in a spreading environment. The harzburgite tectonites are overlain by crustal magmatites of cumulate type. In vertical section they gradually change from Ol-rich to Plg-dominated cumulates. Exploitable chromite concentrations together with newly described mineralization of Pt-group minerals underline its economical importance.
SERPENTINES IN THE OPHIOLITE COMPLEXES OF THE VOURINOS AND KAMVOUNIA MTS. (NORTHERN GREECE)
Abstract: The Vourinos as well as the Kamvounia ophiolite complexes yielded in origin of the serpentine-group minerals of different appearance. In this stage of laboratory studies we have concentrated on: a — filling of shear zones occurring within "basal serpentinites" of the Vourinos Complex (lizardite + chrysotile + splintery antigorite), b — the rock-forming mass of the Kamvounia massif (antigorite), c — slip-fiber "asbestos" within the Kamvounia massif (chrysotile + fibrous antigorite). While the Vourinos Complex during its geological history never reached greenschist facies conditions, the Kamvounia massif underwent metamorphic recrystallization under such conditions.
PETROLOGY OF THE MALA FATRA GRANITOID ROCKS (WESTERN CARPATHIANS, SLOVAKIA)
Abstract: The crystalline core of the Mala Fatra Mts. belongs to the basement of the Tatric Unit in the Western Carpathians. Two segments, the Luka and Krivan, are distinguished in the Mala Fatra Mts., both with large granite plutons. This paper deals with the granitoid rocks of the Krivan segment. On the basis of their mineralogy and geochemistry the hybrid and Magura granite types of Ivanov & Kamenicky (1957) were redefined as I- and S-type granitoids, respectively. The I-type granodiorites and tonalites have a characteristic mineral assemblage of plagioclase (An21–48), Mg-biotite, epidote, interstitial K-feldspar, allanite, hornblende and zircons with I. T. parameter above 350. They are situated mainly on the southern slopes of the Krivan part of the Mala Fatra Mts. The Al-in-hornblende barometer gives a pressure of 330 ± 60 MPa, the zircon and monazite saturation temperatures are between 745–810 °C and 750–810 °C, respectively. The water content of the granitoid magma, estimated on the basis of biotite composition, was about 5 wt. % at 700 °C. This granite suite also contains mafic magmatic enclaves. The S-types granites are localized to the north of the I-type granitoids. They contain plagioclase (An12–35), Fe-biotite, K-feldspar and zircons with I. T. parameter below 300–350. In the absence of hornblende, we suppose the same pressure (330 MPa) for the emplacement of this granite suite. The zircon and monazite saturation temperatures are also within the same range as in the I-type granites (740–790 °C or 720–790 °C). However, the biotite of the S-type granites suggest a lower water content of about 2–4 wt. % at 750 °C. It is noteworthy that according to increasing body of data, the granitoid massifs in a 200 km long region in the present erosion cut between the Male Karpaty and Mala Fatra Mts. were emplaced at similar temperature and pressure conditions. The pressures of 300–400 MPa indicate the similar 12–15 km emplacement depth of all the granitoid bodies in this area.
A NEW OCCURRENCE OF TRIASSIC DEPOSITS NE OF ORAVIŢA (SOUTHERN CARPATHIANS, RUMANIA) AND ITS PALEOTECTONIC SIGNIFICANCE
Abstract: Until recently, in the western part of the South Carpathians Triassic deposits were only known south of the Nera River between Sasca Montană and Moldova Nouă, belonging to the Sasca-Gornjak structural unit (Săndulescu 1975). Core analysis of a borehole drilled NE of Oravita (Brădisorul de Jos) led to the identification of a Triassic formation of the same type and age (Early-Middle Triassic) about 20 km further northerly than previously known. As in the Sasca Montană-Moldova Nouă area, the Triassic deposits are overlain by a Middle Jurassic sedimentary sequence, some tens of metres thick. The paper presents a biostratigraphical analysis of the foraminiferal assemblages that have been identified in the drill core, gives a brief description of the microfacies of the carbonate deposits encountered, and comments on the paleotectonic significance of the newly found Triassic occurrence.
JURASSIC RADIOLARITES FROM THE EASTERN PART OF THE PIENINY KLIPPEN BELT (WESTERN CARPATHIANS)
Abstract: The radiolarites of the Saris and Pieniny part of the Pieniny Klippen Belt belong to the Pieniny Succesion s.l. (Nemcok et al. l990). A horizon of radiolarites from the locality Milpos and Podsadek near Stara Lubovna contains a considerable calcareous admixture. At the localities of Sarisske Jastrabie and Lucka the radiolarites are almost without calcite and contain Mn coatings. The radiolarian associations represent UAZone 8 - UAZone l0 ranging from middle Callovian to early Kimmeridgian (sensu Baumgartner et al. l995). Radiolarites with Mn coatings reach to middle Oxfordian at the locality Sarisske Jastrabie. A new genus Fultacapsa nov. gen. is described in this paper.
TRACE ELEMENT DISTRIBUTION AMONG THE COMPONENTS OF SOILS IN ZITNY OSTROV REGION, SOUTHWESTERN SLOVAKIA
Abstract: Fifteen soil profiles were selected from agricultural areas in Zitny ostrov, and sixty one samples were analysed for their total contents of several trace elements, viz. Ag, As, B, Ba, Be, Cd, Co, Cr, Cu, Ga, Hg, Ni, Pb, Sn, Sr, V, Zn, and Zr. In addition, other soil characteristics have also been determined, viz. particle size, organic carbon, carbonate, cation exchange capacity, and pH. The relations of trace elements with these characteristics were studied using statistical multivariate analysis. Generally, most of the trace elements show strong association with the clays and particularly the organic matter. Consequently, they exhibits strong positive correlation with the cation exchange capacity. They also show strong inter-element relationships which reflect their common occurrence in the clays and organic matter. Sr alone occurs in the carbonate fraction, and Zr in the sand fraction. Vertical distribution of all studied parameters within the soil profiles also proves these conclusions.