Results 1 - 10 of 772
Results 1 - 10 of 772. Search took: 0.02 seconds
|Sort by: date | relevance|
[en] Full text: The basement of metamorphic belts Uruguay supra crustal batholith s are formed on the edges of the existing continental crust during peak crustal accretion and recycling. Emplacement ages inferred correspond to periods preceding the subduction accretion and / or continental collision. Using this model as a basis, constitute a means of recognizing the regime paleostress in ancient archways where magma ascent is controlled by deformation and governed by the partition of property orogenic deformation. In contrast to the continental arches in the collisional orogenic redistribution of mass and energy it is essentially done in the cortex, without significant participation of the mantle. However, the generation of heat granites often needed from the mantle for fusion. Magmatic structures give us clues to reconstruct the tectonic and geological history of high-grade land. A detailed reinterpretation of the structures of the gneissic basement rocks of Eastern Uruguay suggests that despite the presence of a superimposed deformation of solid state, there magmatic structures and linked to the site. For example, the presence of planar and linear structures were often interpreted as corresponding to a metamorphic factory. Many of the rocks before charted as gneiss to be reconsidered as granite structures magmatic and solid deformation superimposed of different magnitude, allow better reconstruction of the geological evolution of the region. The application of these criteria in the extreme southeast Dom Feliciano Belt has allowed us to recognize a set of granitoids with varying degrees of deformation (Unit Campanero), intruded by a suite of Neoproterozoic calc-alkaline granitoids Carapé for the complex. The pretectónicos granites grouped under the name Campanero Unit are represented by a set of heterogeneous bodies sharing the effects of deformation. These granites variable from gneissic texture to mylonitic presented as a foliation most outstanding feature of mylonitic type that generated phenomena of recrystallization (blastesis). Some bands usually present facies of biotite (schiieren). Notwithstanding the absence of geochronological data for Campanero Unit, ongoing studies have yielded paleoproterozoicas ages for these rocks, while for the Land Punta del Este were obtained aged 1100-900 Ma
[en] In general, reservoir rocks can be defined into carbonates, tight elastics and basement rocks. Basement rocks came to be highlighted as their characteristics are quite complicated and remained as a significant challenge in exploration and production area. Motivation of this research is to solve the problem in some area in the Malay Basin which consist fractured basement reservoirs. Thus, in order to increase understanding about their characteristic, a study was conducted in the Eastern part of the Peninsular Malaysia. The study includes the main rock types that resemble the offshore rocks and analysis on the factors that give some effect on fracture characteristic that influence fracture systems and fracture networks. This study will allow better fracture prediction which will be beneficial for future hydrocarbon prediction in this region
[en] The Precambrian crystalline basement of southeast Brazil is affected by many Phanerozoic reactivations of shear zones that developed during the end of the Neoproterozoic in the Brasiliano orogeny. These reactivations with specific tectonic events, a multidisciplinary study was done, involving geology, paleostress, and structural analysis of faults, associated with apatite fission track methods along the northeastern border of the Parana basin in southeast Brazil. The results show that the study area consists of three main tectonic domains, which record different episodes of uplift and reactivation of faults. These faults were brittle in character and resulted in multiple generations of fault products as pseudotachylytes and ultracataclasites, foliated cataclasites and fault gouges. Based on geological evidence and fission track data, an uplift of basement rocks and related tectonic subsidence with consequent deposition in the Parana basin were modeled. The reactivations of the basement record successive uplift events during the Phanerozoic dated via corrected fission track ages, at 387±50Ma (Ordovician); 193±19Ma (Triassic); 142±18Ma (Jurassic), 126±11Ma (Early Cretaceous); 89±10Ma (Late Cretaceous) and 69±10Ma (Late Cretaceous). These results indicate differential uplift of tectonic domains of basement units, probably related to Parana basin subsidence. Six major sedimentary units (supersequences) that have been deposited with their bounding unconformities, seem to have a close relationship with the orogenic events during the evolution of southwestern Gondwana
[en] The invisible, odorless and colorless radon gas is one of the heaviest (by mass) natural sources of radiation. It is 7.7 times heavier than air. In some countries its weight in other natural sources of radiation is 50%. Typically, radon penetrates into the flats and offices through cracks in the foundation of building by infiltration way, as well as leakage in basements and walls. Despite the short half-life period and especially its high density radon gas can accumulate in cellars and the near under-earth territories. The radon concentration in flat happens more than on open space. Mainly, radon gets into a human body in not enough neat flats. In a human body radon first of all influences an irradiation of lungs. Epidemiological researches have confirmed the exact relation between high concentration of radon and probability of diseases by a cancer of lungs.
[en] Low porosity fractured reservoirs have been successfully described, using a combination of high resolution geometrical information from borehole images, together with deeper penetrating log evaluation methods. Borehole images from acoustic or electrical scanning tools provide statistics of the fracture distribution, first order estimates of fracture opening and porosity, and a basis for geological inferences. Their drawback is that, in this environment, the events on the images bear a strong overprint of the drilling process. Deeper penetrating, but lower resolution techniques, such as Stoneley wave reflectance and deep resistivity log inversion are used to distinguish the deep and permeable fractures that may contribute to flow. By ma king some assumptions about the nature of porosity in basement reservoirs, we develop a new method to estimate the porosity and the fraction of this secondary porosity is developed due to fractures. This method makes the use of the Kuster-Toksoz acoustic scattering model and requires low frequency measurements of compressional and shear velocities
[en] Fullerene is a well-known carbon nanomaterial, which can be potentially used for drug manufacture or delivery. Despite several successful examples of utilizing fullerene derivatives as drug candidate materials, their low water solubility under physiological conditions negatively affects the cell penetration efficiency after treatment. In this work, we successfully synthesized two fullerene derivatives with covalently attached fluorescein and boron dipyrromethene (BODIPY) fluorophore moieties, which exhibited cellular uptake and intracellular localization. While both fluorophores decreased their fluorescence intensity in the vicinity of fullerene, the cellar uptake of the fluorescein-modified fullerene was detected via fluorescence microscopy observations. Moreover, decreases in the fluorescence intensities of the intact fluorescein and BODIPY species were observed when both fluorophores and fullerene coexisted in aqueous media.
[en] This work is about the Piedras de Afilar lithostratigraphic formation which is part of Tandilia Precambrian terrain of Uruguay. This sedimentary sequence of Neo proterozoic age is supported by a Paleoproterozoic basement
[en] Isotopic ages from metamorphic and plutonic rocks of the Atlantic area of North Patagonian basement indicate that the main crustal tectonic events occurred during the late Proterozoic to early Paleozoic times. Rb/Sr and U/Pb data in the 550-470 Ma interval suggest an old tecto-thermal activity during the upper Brazilian Cycle (Rio Doce Orogeny). At regional scale, the comparable Neo proterozoic basement of Ventania and sedimentary for eland cover of Tandilia continues to the Northeast, in the Dom Feliciano Belt. A possible correlation of the North Patagonian basement with igneous-metamorphic relics of Central Argentina (Pampean Ranges of San Luis-Cordoba and at La Pampa province) is also indicated. (author)
[en] Groundwater exploration in either a basement or sedimentary environment is often fairly well defined and focuses on delineating weathered/fractured rocks or saturated formations, respectively. Conversely, unique geological structures, the complex coexistence of different rock types and poorly defined basal/lateral contacts between basement and sedimentary rocks make groundwater development in a geological transition environment very challenging. Ijebu-Ode and its environs lie within such a problematic transition zone, between the Precambrian basement rocks and Cretaceous sediments of the Dahomey Basin, in southwestern Nigeria, where associated acute groundwater development challenges require adequate subsurface information to maximize its groundwater resource potential. This study integrated very low frequency electromagnetic (VLF-EM) and electrical resistivity (ER) geophysical prospecting techniques for a detailed terrain study of Ijebu-Ode in order to establish the reasons for the low groundwater resource potential in the area. Thirty five VLF-EM profiles, 140 vertical electrical soundings (VES) and relevant hydrogeological data were acquired along grids and profiles. Data were filtered, inverted and enhanced using appropriate software packages. The current density and geoelectric parameters of the VLF-EM and VES data were employed to generate terrain maps, the conductivity distribution and a subsurface basement model of the study area. Current density plots and geoelectric parameters identified up to three layers in the basement complex terrain which comprised lateritic topsoil, weathered basement and fresh basement rocks. The five layers encountered in the sedimentary terrain were topsoil, a lateritic unit, a dry sandy unit, a saturated sandy unit and fresh basement rocks. The hydraulic conductivity of the thick (3–18 m) lateritic unit was determined to be 1.32 × 10−5 mm s−1, while that of the underlying sandy units ranged from 2.65 × 10−4 to 1.36 × 10−3 mm s−1. The thick but less permeable lateritic unit which overlaid the more permeable rocks constituted a partial impermeable overburden that prevented an adequate groundwater recharge during and immediately after rainfall. Three zones were delineated as low, medium and high groundwater resource potential areas, located in the northern, central and southern part of the study area, respectively. The low groundwater resource potential around Ijebu-Ode is due to the less permeable lateritic overburden, which prevents an adequate recharge during rainfall and the rugged/undulating basement topography that controls the distribution and storage of the limited recharged water. The southern part of the study area can be developed to meet the water needs of the inhabitants. (paper)