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Emplacement mechanisms and structural influences of a younger granite intrusion into older wall rocks - a principal study with application to the Goetemar and Uthammar granites. Site-descriptive modelling SDM-Site Laxemar  

Energy Technology Data Exchange (ETDEWEB)

The c. 1.80 Ga old bedrock in the Laxemar-Simpevarp area, which is the focus of the site investigation at Oskarshamn, is dominated by intrusive rocks belonging to the c. 1.86-1.65 Ga Transscandinavian Igneous Belt (TIB). However, the site investigation area is situated in between two c. 1.45 Ga old anorogenic granites, the Goetemar granite in the north and the Uthammar granite in the south. This study evaluates the emplacement mechanism of these intrusions and their structural influence on the older bedrock. Field observations and structural measurements indicate that both the Goetemar and the Uthammar granites are discordant and have not imposed any significant ductile deformation on their wall-rocks. The apparent conformity of geological contacts and fabrics in the wall rocks and the southern margin of the Goetemar granite is coincidental and inherited from the pattern of Svecokarelian deformation of the TIB. However, interpretation of regional aeromagnetic data suggests that the granites occur within a broad, NNE-SSW trending linear belt, pointing to deep seated tectonic control on their generation, ascent and emplacement. Thermochronology indicates that the granites were emplaced at depths between 4 and 8 km into brittle wall rocks. The 3-D shape of the Goetemar and Uthammar plutons has been investigated by 2.75D forward modelling of the residual gravity anomalies due to both granites. Both granites are associated with strong residual gravity anomalies of up to -10 mgal. Constraints on the geometry of the plutons at the surface are provided from surface geology maps and several deep boreholes located on or close to the model profiles. A further variable in the gravity modelling is introduced by either allowing the upper contact of the plutons to assume the most suitable orientation to produce the best fit between the modelled and observed gravity ('unconstrained models') or by forcing the near surface orientation of the contacts to be vertical ('constrained models'). The unconstrained model profiles for both plutons are characterized by gently outward dipping upper contacts to depths approx1 km, gently inward dipping lower contacts and a thin, centrally located root extending to depths of 5 to 10 km. However, this geometry is not supported by available boreholes, which do not penetrate the upper contact of the Goetemar pluton as predicted by the models. The constrained models are consistent with borehole data. They characterize the plutons as having vertical contacts in the upper 500 to 1,000 m, a 1,000 to 1,500 m thick mid-level body with outward dipping upper and horizontal and lower contacts, respectively, and broad roots extending to depths of approx4 km. Preliminary observations and gravity modelling results indicate that the Goetemar and Uthammar granites are discordant plutons with geometries most consistent with punched laccoliths, with some modification due to floor subsidence due to root development. Their vertical and lateral dimensions fall in the upper range for laccoliths and lower range for plutons as defined by recent data compilations. Their emplacement required elastic bending and eventual failure of roof rocks that was likely accompanied by reactivation of pre-existing fractures and shear zones and possibly the creation of new brittle fractures. Cooling and crystallization of the granites resulted in thermal resetting of the wall rocks and the establishment of a transient hydrothermal system, now recorded by fracture filling mineral assemblages

Cruden, Alexander R. (Dept. of Geology, Univ. of Toronto (Canada))

2008-12-15

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Emplacement mechanisms and structural influences of a younger granite intrusion into older wall rocks - a principal study with application to the Goetemar and Uthammar granites. Site-descriptive modelling SDM-Site Laxemar  

International Nuclear Information System (INIS)

The c. 1.80 Ga old bedrock in the Laxemar-Simpevarp area, which is the focus of the site investigation at Oskarshamn, is dominated by intrusive rocks belonging to the c. 1.86-1.65 Ga Transscandinavian Igneous Belt (TIB). However, the site investigation area is situated in between two c. 1.45 Ga old anorogenic granites, the Goetemar granite in the north and the Uthammar granite in the south. This study evaluates the emplacement mechanism of these intrusions and their structural influence on the older bedrock. Field observations and structural measurements indicate that both the Goetemar and the Uthammar granites are discordant and have not imposed any significant ductile deformation on their wall-rocks. The apparent conformity of geological contacts and fabrics in the wall rocks and the southern margin of the Goetemar granite is coincidental and inherited from the pattern of Svecokarelian deformation of the TIB. However, interpretation of regional aeromagnetic data suggests that the granites occur within a broad, NNE-SSW trending linear belt, pointing to deep seated tectonic control on their generation, ascent and emplacement. Thermochronology indicates that the granites were emplaced at depths between 4 and 8 km into brittle wall rocks. The 3-D shape of the Goetemar and Uthammar plutons has been investigated by 2.75D forward modelling of the residual gravity anomalies due to both granites. Both granites are associated with strong residual gravity anomalies of up to -10 mgal. Constraints on the geometry of the plutons at the surface are provided from surface geology maps and several deep boreholes located on or close to the model profiles. A further variable in the gravity modelling is introduced by either allowing the upper contact of the plutons to assume the most suitable orientation to produce the best fit between the modelled and observed gravity ('unconstrained models') or by forcing the near surface orientation of the contacts to be vertical ('constrained models'). The unconstrained model profiles for both plutons are characterized by gently outward dipping upper contacts to depths ?1 km, gently inward dipping lower contacts and a thin, centrally located root extending to depths of 5 to 10 km. However, this geometry is not supported by available boreholes, which do not penetrate the upper contact of the Goetemar pluton as predicted by the models. The constrained models are consistent with borehole data. They characterize the plutons as having vertical contacts in the upper 500 to 1,000 m, a 1,000 to 1,500 m thick mid-level body with outward dipping upper and horizontal and lower contacts, respectively, and broad roots extending to depths of ?4 km. Preliminary observations and gravity modelling results indicate that the Goetemar and Uthammar granites are discordant plutons with geometries most consistent with punched laccoliths, with some modification due to floor subsidence due to root development. Their vertical and lateral dimensions fall in the upper range for laccoliths and lower range for plutons as defined by recent data compilations. Their emplacement required elastic bending and eventual failure of roof rocks that was likely accompanied by reactivation of pre-existing fractures and shear zones and possibly the creation of new brittle fractures. Cooling and crystallization of the granites resulted in thermal resetting of the wall rocks and the establishment of a transient hydrothermal system, now recorded by fracture filling mineral assemblages

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Uranium potential of the younger granites of Egypt  

International Nuclear Information System (INIS)

The post-tectonic Pan-African younger granites of Egypt are characterized by abnormal radioactivity. Several plutons of these granites in the Eastern Desert, host a variety of rare metal mineralizations including uranium. Two younger granite plutons, namely El Missikat and El Erediya, in the central part of the Eastern Desert, host siliceous vein-type uranium mineralization, which is structurally controlled by faults and their feather joints associated with NE and NNE trending shear zones. The Gattar granite pluton, at the northern part of the Eastern Desert, hosts vein-type uranium mineralization associated with molybdenite. At the southern part of the Eastern Desert, Um Ara granite pluton hosts uranium as disseminated unconformity contact type. Pitchblende is the primary mineral, while secondary uranium minerals are mainly: uranophane, ?-uranophane, soddyite and renardite. Small amounts of pyrite, chalcopyrite, galena, sphalerite, molybdenite and violet fluorite are present in association with the uranium mineralization in the mineralized zones. Present data suggest an origin by hydrothermal fluids derived from the granitic magma. Redistribution by circulating meteoric water may have taken place as evidenced by widespread alteration, particularly silicification. Exploratory mining resulted in clarifying the possibility of the extension of the uranium mineralization zone laterally and in depth. The estimation of the uranium potentiality of the four younger granite potentiality of the four younger granite plutons is 14000 tons uranium as speculative resources. (author). 25 refs, 1 fig., 1 tab

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Contribution to uranium geochemistry in intrusive granites  

International Nuclear Information System (INIS)

This work aims to define the position of a certain number of French granitic deposits within the field of the geochemistry of granites in general, and of the geochemistry of uranium in particular. The regions concerned are: - 3 French Hercynian ranges, in the Vendee, in Brittany and in the Morvan, - 1 African range, probably precambrian, of the Hoggar. For each range, the petrochemical framework is first of all determined and then the degree of chemical homogeneity of the rocks is evaluated. In the petrochemical groups thus obtained the geochemical behaviour of the uranium is studied. From a point of view of the geochemistry of the granites under investigation, a comparison of the laws of distribution of the major elements in the 4 ranges shows up a convergence of average composition which was not anticipated by geological and petrographic considerations alone. The statistical and geochemical distribution laws of the total uranium as a function of the petrochemical variations are established. A study of the chemical forms of uranium in the rocks has drawn an attention to the qualitative and quantitative importance of the fraction of this uranium soluble in dilute acids. We have therefore reconsidered on the one hand, the laws of distribution of the insoluble uranium, which represents essentially the uranium fixed in crystalline structures (zircon, allanite...), and we have justified on the other hand the interest presented by the soluble uranium: this, although more complex in character, presents a geochemical unity in post magmatic phenomena which makes possible to find a genetic connection between the uraniferous deposits and the intrusive massifs. Finally we have given a plan of the geochemical cycle of uranium, in which we hope to have provided some more accurate data on the igneous phase. (author)

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Characteristics and significance of uranium bearing pan african younger granite in the eastern desert, Egypt  

International Nuclear Information System (INIS)

Surficial uranium mineralization was discovered in four pan african younger granite plutons in the eastern desert of egypt. The present study revealed great similarity between these plutons both in petrography and geochemistry. They are two-feldspar, two-mica peraluminous granites which have been formed by melting of crustal materials and emplaced during the late stage stage of a late proterozoic orogenic cycle. Radiometric and geochemical investigations indicate that these granites are fertile with respect to U and form a potential target for primary uranium deposits. Four models are suggested to explain the source and mechanism of the surficial uranium mineralization in these granites. The most applicable model is the oxidation of U+4 found in minute disseminated uraninite grains and its subsequent mobilization. This is supported by petrographic and autoradiographic studies. The bearings of the present study on further exploration for uranium deposits in granites of the arabian- Nubian shield in general are discussed

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Intrusive rocks from Polumir and Željin (Serbia): two contrasting granit?id types  

OpenAIRE

This paper outlines correlation of the most distinctive features of intrusive rocks from Polumir (granite from Polumir, Polumir granite) and from Željin (Željin granitoid). Although these two intrusions are notable similar in space (10-12 km) and time (beginning of Miocene), they are very different, even contrasting concerning their petrography, genesis and geotectonic. Mineralogy, petrology and chemistry of Polumir granite (P?2.5 km2), and of Željin quartz diorite and tonalite, as well ...

Milenko

2014-01-01

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Uranium in the Niger-Nigeria younger granite province  

International Nuclear Information System (INIS)

In Niger, uranium occurs in upper Palaeozoic and lower Mesozoic continental sedimentary basins west of the Air Mountains, but the source of the uranium had not been identified. Geochemical studies and fission-track observations on alkaline ignimbrites preserved in two Palaeozoic anorogenic centres in Air show that uranium is concentrated in the matrix and on secondary iron-oxide coatings surrounding lithic and crystal fragments. Based on variable Th/U ratios and degree of oxidation, it is concluded that the original ignimbrite field was enriched in uranium, but that a considerable proportion was leached during the weathering of the volcanic pile. Tectonic uplift, anorogenic magmatism, followed by weathering and erosion of the volcanic cover, with sedimentation in nearby continental basins, have all contributed to the development of uranium mineralization in Niger. The petrological and geochemical similarities between the Palaeozoic ring complexes in Niger and the Nigerian Mesozoic ring structures suggest that sedimentary uranium deposits may also be found in Nigeria if the tectonic and sedimentological controls were favourable. Enriched concentrations of uranium have been discovered in the exposed granitic roof zones of the Nigerian subvolcanic centres, with Th/U ratios approaching unity. (author)

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Gravity interpretation of the Zaranda Younger Granite ring complex, Nigeria  

Science.gov (United States)

Gravity and geological data were collected over the Zaranda complex situated near Bauchi, Nigeria for a critical analysis of the deep structure in the area. The result of the study shows that, in addition to the host migmatitic gneiss, five major rock types form the complex. These are leixocratic and melanocratic syenites, granite porphyry, trachytes and basalts, and mafic-rich enclaves in the basement. A negative residual gravity anomaly of about - 10.6 mGal is centred on the complex. This negative residual is bordered on the eastern and southern margins by relatively positive residual anomalies of up to +5.2 mGal. The main negative anomaly displays a prominent NE-SW trend which is similar to those of the major structures in the basement, suggesting that the complex might have intruded the host migmatic gneiss through pre-existing structures. There is also good correlation between the residual anomalies and the geology, with the negative anomalies occurring over areas underlain by low density rocks corresponding to trachyte (2.56 × 10 3 kg m -3), syenite (2.62 × 10 3 kg m -3); while positive anomalies correspond to areas of basic rocks (2.76-2.92 × 10 3 kg m -3). 2-D and 3-D gravity modelling showed that the major pluton of the complex is the syenite body which extends to a depth of about 5.5 km. The mineralogy and chemistry of the rocks in the Zaranda complex suggest that the complex may be underlain by a zone of mafic rocks, as shown by field occurrence of hornblende-rich enclaves in the basement.

Ibe, K. K.; Ajakaiye, D. E.; Ojo, S. B.

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Uranium-bearing siliceous veins in younger granites, Eastern Desert, Egypt  

International Nuclear Information System (INIS)

The post-tectonic younger granites of Egypt represent the magmatic activity marking the end of the cratonization process of the Pan-African Orogeny. Several of these plutons are hosts of rare metal mineralization in the Eastern Desert of Egypt. Two of them, namely El-Erediya and El-Missikat plutons, are hosts of siliceous vein-type uranium mineralization. In both occurrences, the mineralization is structurally controlled by faults and their feather joints which are associated with NE to ENE shear zones. Widespread silicification, and to a lesser extent kaolinization and sericitization, as well as other alterations accompany the uranium mineralization. Uranium is concentrated in the centre of the mineralized faults and fractures together with jasper (in El-Erediya) or black silica and to a lesser extent jasper (in El-Missikat). Pitchblende is the primary mineral which suffered intensive oxidation and probably leaching relics protected by silica. This resulted in a spotty distribution of uranium and radioactivity in the oxidation zone. Present data suggest an origin by hydrothermal fluids derived, most probably, from the younger granite magma. Uranium was derived from the magma itself, or from another deep source. Contributions from the granitic plutons by leaching through circulation of meteoric waters cannot be ruled out at the present state of knowledge. (author)

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Intrusive rocks from Polumir and Željin (Serbia: two contrasting granit?id types  

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Full Text Available This paper outlines correlation of the most distinctive features of intrusive rocks from Polumir (granite from Polumir, Polumir granite and from Željin (Željin granitoid. Although these two intrusions are notable similar in space (10-12 km and time (beginning of Miocene, they are very different, even contrasting concerning their petrography, genesis and geotectonic. Mineralogy, petrology and chemistry of Polumir granite (P?2.5 km2, and of Željin quartz diorite and tonalite, as well as of granodiorite and granite (P?56 km2, i.e. properties that directly reflect on their genesis and geotectonic setting, are presented in this paper. Chemistry of biotite, the only mineral observed in both plutons, as the direct evidence of different physical-chemical conditions during consolidation and proof for their genetic contrast, is contributed.

Milenko

2014-11-01

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Genesis of Uranium in the younger granites of gabal abu hawis area, central eastern desert of Egypt  

International Nuclear Information System (INIS)

The younger granites cropping out in gabal abu hawis area are considered as uraniferous (fertile) granites (the fertile is mainly is mainly attributed to presence of radioactive zircon). Abu hawis granitic pluton is dissected by joints faults of different trends forming two mineralized shear zones in the northern peripheries and southern border. The younger granites hosting uranium mineralizations along the two mineralized shear zones. The uranium minerals include uranophane and carnotite. The altered granites have much lower Th/U ratios (0.03-0.10) than those of the fresh granites (1.69-2.05), indicating strong mobilization of uranium in this pluton by super-heated solutions that resulted from supergence meteoric water as well as U-addition by hypogene fluids. These solutions could pass through the structural network of fractures, joints and fault planes and have leached some of labile uranium from the surrounding rocks and/or the younger granites themselves. Then, changing in the physicochemical conditions of these solutions caused uranium precipitation as uranium minerals filling the cracks in the rock and/or adsorbed on the surface of clay minerals and iron oxides in the two shear zones

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Oxygen isotope geochemistry of the Granite Harbour Intrusives, Wilson Terrane, Northern Victoria Land, Antarctica  

International Nuclear Information System (INIS)

The oxygen and strontium isotope compositions of the Cambro-Ordovician granitoids cropping out in the Wilson Terrane (Granite Harbour Intrusives-GHI) constrain the petrological evolution of the magmatism in Antarctica, related to the Ross Orogeny. The measured ?18OWR values of three intrusives define three different compositional groups: the metaluminous rocks (MAG), with ?18OWR ranging from 6.9 (olivine gabbro) to 11.4 %o (monzogranite); the unaltered peraluminous granites (PAG), having ?18OWR values ranging from 10.6 to 13.2 %o, and the foliated peraluminous leucogranites (SKG), characterized by ?18OWR values above 14 %o. The analysis of equilibrium mineral assemblages indicates that the high ?18OWR values are magmatic and unaffected by low-temperature processes. A few peraluminous granites sampled in the vicinity of Cenozoic intrusions show anomalously low ?18OWR, due to meteoric-hydrothermal alteration. The isotopic data indicate that the coeval and spatially related metaluminous mafic and felsic intrusives forming the GHI were not comagmatic: the mafic and intermediate rocks were likely derived from lower crustal contamination of a pristine basaltic magma; their ?18OWR values were also increased during emplacement, due to the interaction with the adjacent 18O-rich hydrous felsic magmas (mixing)rich hydrous felsic magmas (mixing). Oxygen isotope data indicate that the crustal sources producing the granite harbor intrusives were not homogeneous: the felsic metaluminous intrusives were produced by partial melting of fertile rock with possible igneous origin, whereas partial melting of a metapelitic source rock is claimed for the genesis of the peraluminous granites. (author)

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Three Paleoproterozoic A-type granite intrusions and associated dykes from Kainuu, East Finland  

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Full Text Available Mafic and felsic intrusive rocks aged 2.5–2.4 Ga have been observed over a large area in eastern and northern Finland, as well as in adjacent northwestern Russia. We describe three granite intrusions and associated dykes from Kainuu, Finland, that belong to this bimodal magmatic event. All these three granites show clear A2-type chemical affinities with high Y/Nb, HREE, Fe/Mg, Ga and Nb. Two of the intrusions, Rasinkylä and Pussisvaara, were dated at 2425±3 and 2427±3 Ma, respectively, using thermal ionisation mass spectrometry utilizing the chemical abrasion method (CA-TIMS. CA-TIMS ages are supported by single-grain age determinations obtained by using Laser Ablation Multicollector Inductively Coupled Plasma Mass Spectrometer (LA-MC-ICPMS. New data on the previously described Rasimäki granite from southern Kainuu is presented, including an age of 2389±5 Ma obtained with LA-MC-ICPMS. The variable magnetite content of the granites is proposed to reflect the differences in the oxidation state of the source, which in our interpretation is the local Archean lower crust. Partial melting and the emplacement of the granites occurred in an extensional environment. Heat for the partial melting was provided by mafic magmas under and intraplating the extended crust.

Hannu Huhma

2010-12-01

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Age of the Mulcahy Lake intrusion, northwest Ontario, and implications for the evolution of greenstone-granite terrains  

International Nuclear Information System (INIS)

Zircon data from a 63 km2 layered mafic intrusion in the Wabigoon subprovince, the Mulcahy Lake gabbro, show that the gabbro crystallized at 2733.2(+1.0-0.9) Ma. The largely unaltered and unmetamorphosed gabbro intrudes tholeiites of the Crow Lake-Savant Lake greenstone belt which were generated over at least a 10 Ma time span. Rb-Sr and Sm-Nd data were obtained for pristine whole rock and mineral separates from the intrusion. The Rb-Sr data show disturbances in the system, particularly in the case of pyroxenes. Samples with low Rb/Sr ratios indicate an initial Sr ratio of 0.7007 for an age of 2733 Ma. The Sm-Nd age is 2744+-55 Ma, and an epsilon Nd value of +2.6+-1.2 indicates a light rare earth element depleted source. The Sm-Nd data shows less disturbance than the Rb-Sr data. Granitic and mafic intrusives with similar initial ratios occur 80 km to the south in the Quetico subprovince. Primary hornblende was analyzed for 40Ar/39Ar. The age obtained is 2703+-20 Ma, clearly younger than the zircon age indicating some argon loss. (orig.)

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Discriminations of Younger Granitic Masses at Gabal Qattar Area, North Eastern Desert, Egypt, Using Remote Sensing Techniques  

International Nuclear Information System (INIS)

Gabal Qattar area is located in the north Eastern Desert of Egypt between Latitudes 26 degree 52 and 27 degree 08 N, and Longitudes 33 degree 13 and 33 degree 25 E. The exposed rock units, there, from the oldest to the youngest, are meta volcanics; granodiorites- diorite complex; Hammamat sediments and younger granites. Most of the area is densely traversed by felsic and mafic dykes. The Qattarian younger granites are divided into seven granitic areas according to their spectral characters to facilitate the studying and delineating physical characteristic differences between these areas as well as to throw a light about the best conditions of exploration for radioactive mineralizations. This study is based on brightness Digital Number values (DNs) of the granitic areas, predominant trends and densities of the structural lineaments, shape and type of weathering products. Three areas of these seven younger granite areas form Gabal (G.) Qattar, and designated Gr 1, Gr 3 and Gr 4, where the other granite areas which form the G. Urn Dissi (Gr 2), G. Thelma (Gr 5), G. Abu Samyuk (Gr 6) and G. Ayn AI Ruwayshed (Gr 7). Photo geologically, these seven granite areas show some differences in shape, texture, predominant trends and densities of structural lineaments and ability of weathering. This study shows that the seven granite areas could be gathered into three main groups according to their DNs values of Landsat ETM+ spectral bands especially of band 5, where these three maispecially of band 5, where these three main groups representing different, and mainly coincide with the three granite phases previously delineated according to chronological field relation, petrographic and geochemical studies. The Gr 1 area contains all uranium occurrences from locations I to V. This area is characterized by semi circular shape of NW trend, massive appearance with high relief peaks, and high fracture density, where the N 55 degree E, N 5 degree E, N 45 degree E and N 45 degree W are the predominant trends. Some of the N 55 degree E fractures form shear zone along the contact with Hammamat sediments. This granitic area displays taffoni weathering with highest clay minerals content in its weathered surfaces. It shows the highest brightness value (DN), especially in band 5 reaching about 152, due to the highest felsic minerals and the lowest ferro magnesian minerals contents relative to the other granite areas. Also, the high fractures density of the Gr 1 area acted as good channels for the hydrothermal ascending fluids and the percolating meteoric water, that leached uranium mineralization and redeposited it in the shear zones especially at sites of intersection of the main fractures. These characteristic features of the Gr 1 area may be responsible for the presence of uranium mineralizations

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Age of Pedra Branca granite (Goias) and possible geotectonic implications  

International Nuclear Information System (INIS)

Rb-Sr geochronologic dating of granites from the Pedra Branca Granite Massif (Nova Roma, Goias) shown an age of 1405 ± 21My. and a questionable initial Sr87/Sr86 ratio of 0,7004 ± 0,006. Rhyolite from the base of the Arai Group is probably of the same age as the granitic intrusion. The 475 ± 19 My. age for the granitic intrusion is evidence of the Brasiliano Cycle imprint in Pedra Branca region. The age attributed to the Pedra Branca Granite is lower than known ages of the Goias tin granites giving rise to new geotectonic interpretations. It is possible that the Pedra Branca Granite represents a low-level intrusion emplaced at the beginning of structuration and deposition of the Arai basin. It may be correlated with granitic intrusions related to a rift stage above mantle hot spots, like the Nigerian tin younger granites. (author)

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Granite intrusion in a metamorphic core complex: the example of the Mykonos laccolith (Cyclades, Greece)  

Science.gov (United States)

Numerical and analogical modelling underlined the importance of a pre-existing anomaly of viscosity-density such as a granite or migmatitic body below the brittle-ductile transition as a primary cause of metamorphic core complex (MCC) developpement. While field studies of MCC show a spatial and temporal link between MCC formation and plutonic activity, thermochronological studies show that there is no link between the intrusion of granites and the velocity of slip on the detachement plane. The Aegean domain is a good natural laboratory for studying the formation of MCC and syn-tectonic granites. In the northern Cyclades, the Mykonos-Delos-Rhenia MCC is characterised by the intrusion of a plurikilometric Late Miocene pluton of I-type granite within a migmatitic gneiss dome. AMS (Anisotropy of magnetic susceptibility) and microstructural studies in the Mykonos granites combined with recent cooling rate data allow us to use the granites as strain marker. The Mykonos granitoïds form a plurikilometric laccolith slightly deeping to the east and presenting an elliptical shape with a N170°E long axis. The laccolith is strongly asymmetrical with an outlying root zone in the SW cropping out on Delos and Rhenia islands and a major body mainly developed to the NE and cropping out on Mykonos Island. The laccolith consists of various petrographic facies presenting straight contacts that demonstrate emplacement by successive pulses of more or less differentiated magmas. The laccolith was developed at the interface between the Cycladic Basement and the Blueschists Unit and within the Blueschist Unit. Two events of deformation have been recorded in the granites. The first event is characterized by submagmatic and high to middle temperature protomylonite microstructures developped during or just after the intrusion. The second event of deformation characterized by low temperature mylonites and cataclasites close to the major detachment fault corresponds to the localization of deformation at the top of the laccolith after cooling due to heat exchange with country rocks and exhumation of the Mykonos MCC. The study of fabric evolution in the laccolith suggests that the laccolith structuration results from the interaction between regional deformation and lateral extension of magmas. Fabrics are indeed strongly planar close to the detachment, show an evolution toward plano-linear close to the bottom of the laccolith and are strongly linear in the root zone. Structural data suggest an evolution of the Mykonos MCC in three stages as follows: (i) a first stage characterized by the formation of a migmatitic "a-type dome" with a major axis parallel to the lineation such as Naxos dome by competition between regional N20 extension and EW shortening; (ii) a second stage marked by the emplacement of the Mykonos laccolith at 13 Ma at the top of the migmatitic paragneiss in the Blueschist Unit (iii) a progressive localisation of the deformation occured at the top of the laccolith in semi-ductile conditions on a thickness at about 500 m and thus in brittle conditions in the major detachment plane. Our study shows that intensity of submagmatic to high temperature deformation observed in the laccolith remains low compared to the deformation observed in country-rocks. This suggests that intrusion of a laccolith in the roof of a MCC in partially molten rocks does not localize the deformation. By contrast the geometry of the intrusion shows that the magmas are sucked into the direction of regional extension and that the intrusion of magmas will inevitably cause a local acceleration of the MCC development. Finally, during its cooling the laccolith will localize the brittle ductile transition in its roof and caused the formation of a strong deformation zone first ductile and then brittle.

Denèle, Yoann; Lecomte, Emmanuel; Jolivet, Laurent; Huet, Benjamin; Labrousse, Loïc.; Le Pourhiet, Laetitia; Lacombe, Olivier

2010-05-01

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Depth Estimation of Digitized Aeromagnetic Data of the Western Part of the Younger Granite Rocks of North Central Nigeria, West Africa  

OpenAIRE

The present study is aimed at estimating the depths extents of aeromagnetic anomalies over the younger granite rocks and their associates in the western part of North Central Nigeria. The Younger Granites rocks of North Central Nigeria are characterized by total magnetic intensity values ranging from 32670 to 33070 nanoTesla (nT). Most of the anomalous features trend in the northeast-southwest direction. Medium to higher magnetic intensity values occupy more than three quarter of the area. Th...

Alkali, S. C.; Gaiya, S.; Abba Musa, B.

2012-01-01

19

Pegmatoid schlieren with tourmaline in granitoids of eastern russia as an attribute of intrusive series completed by ore-bearing Li-F granites  

Science.gov (United States)

Tourmaline schlieren in pegmatoids and host granites are widespread in Cretaceous granitoid plutons occurring in tin districts of eastern Russia. These schlieren were formed under the action of fluoricboron fluids, which are considered to be forerunners of rare-metal granite magmatism. The tourmaline schlieren in adamellites, biotite, and two-mica granites are reliable attributes of intrusive series completed by emplacement of ore-bearing Li-F granites.

Alekseev, V. I.; Marin, Yu. B.

2014-12-01

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Geochemical Characteristics and Chemical Electron Microprobe U-Pb-Th Dating of Pitchblende Mineralization from Gabal Gattar Younger Granite, North Eastern Desert, Egypt  

OpenAIRE

Pitchblende mineralization was studied in the younger granite samples collected from Gabal Gattar, north Eastern Desert, Egypt using electron scanning microscope (ESM) and electron probe microanalyses (EPMA). This study revealed that this pitchblende contains significant Zr content reaching up to (66.80% ZrO2), which suggests that volcanic rocks were probably the source of such a deposit. High level emplaced high-K Calc-alkaline plutons as Qattar granite may have bee...

Shahin, Hassan A. A.

2014-01-01

21

Assessment of the radiological consequences of human intrusion into repositories located in granite  

International Nuclear Information System (INIS)

The method used in France to assess the radiological impact of waste repositories in granite consists in making a deterministic analysis of the normal evolution scenario (base case scenario) and a limited number of altered evolution scenarios which, for each series of plausible scenarios, are those with the greatest potential impact. In view of the importance of the human intrusion scanario, and following a request from the working party on site selection criteria chaired by Professor Goguel, a study has been made of this scenario under the CEC PAGIS project. A description of the Auriat site drawn up under the PAGIS project was used as a basis for analyzing the radiological consequences of an intrusion (after periods ranging from 1 000 to 100 000 years subsequent to closure of the repository) assumed to result in the creation of a cavern equivalent to a cube measuring 100 m along each side. Three different scenarios were considered (mine worker, stock rearing, gardening). Except for the mine worker scenario, which produced exposure rates of up to 10 millisieverts/year, a figure that is in fact comparable to the dose to which workers in conventional mines are exposed, the calculated dose equivalents were relatively low

22

Kuznechensky intrusion of K-rich porphyric granites: U-Pb data and tectonic position (Baltic shield)  

International Nuclear Information System (INIS)

For studying the conditions and age range of formation of the Kuznechensky intrusion (Baltic shield) the U-Pb isotope dating of zircon and monazite within granites of the intrusion mentioned was performed. Bearing in mind the morphological characteristics of the zircon studied, suggesting its magmatic origin, the age value obtained, equal to 1874 ± 4 mln. years, is referred to the time of the massif crystallization. The monazite age (1851 ± 5 mln. years) reflects the period of its U-Pb system closing and corresponds to metamorphism time

23

Petrography and major element geochemistry of the younger granites of Sindhudurg district, Maharashtra, India and their bearing on the associated radioactive pegmatites  

International Nuclear Information System (INIS)

The Precambrian metasediments exposed in the Sindhudurg district of Maharashtra are intruded at numerous places by the younger granites and associated pegmatites. The pegmatites are radioactive at a number of places and have analysed 3O8 and 2. The granites are two-mica bearing peraluminous with fairly uniform composition and relatively high uranium (11-21 ppm) content, post-orogenic and appears to have formed by crustal anatexis at a minimal temperature of 685 deg at a relatively PH2O of 5 kb (assumed). The initial granitic melt formed was rich in uranium and its subsequent crystallisation and differentiation resulted in the concentration of U and Th and rare metals of Nb, Ta in the residual and subsequent pegmatitic fluids, manifested mineralogically as uraninite and columbite in pegmatite associated with these granites. (author)

24

Characteristics of pegmatoidal granite exposed near Bayalan, Ajmer district, Rajasthan  

Science.gov (United States)

The study involves the characterization of pegmatoidal granite, southeast of Beawar, Ajmer district, Rajasthan. Earlier researchers had described this granite as part of the BGC, basement to the Bhim Group of the Delhi Super Group rocks. However, the present study indicates that it is younger than the rocks of Bhim Group of South Delhi Fold Belt, into which it is intrusive. The intrusion is structurally controlled and the outcrop pattern is phacolithic. The granite had intruded post-D2 deformation of the Delhi orogeny along the axial planes of D2 folds. The intrusion has also resulted in the formation of a contact aureole about the calc gneisses.

Dasgupta, Nilanjan; Pal, Taritwan; Sen, Joydeep; Ghosh, Tamoghno

2011-08-01

25

Interactions between extensional shear zones and syn-tectonic granitic intrusions: the example of Ikaria Island (Cyclades, Greece)  

Science.gov (United States)

The Aegean domain is an ideal place to investigate the development of Metamorphic Core Complex (MCC) and to study the role of syn-tectonic granites on their development. MCCs of the Aegean domain are dynamically associated with a few major detachments, especially the North Cycladic Detachment System (NCDS) and the West Cycladic Detachment System (WCDS), which have accommodated a large part of the crustal thinning during the Oligocene and Miocene. The NCDS extends toward the East within the Simav Detachment that has exhumed the northern high-temperature part of the Menderes massif. The transition between the NCDS and the Simav Detachments is located above a major tear in the Aegean slab whose effects on lithospheric deformation are far from understood. The Aegean granitoids were emplaced during the Middle Miocene within a zone of high-temperature during the episode of slab tearing and recorded increments of extensional tectonics within this complex zone. Ikaria Island (Cyclades, Greece) is a metamorphic dome intruded by three Miocene granitoid plutons (one I-type intrusion, two S-type ones) including the largest pluton of the Aegean domain. However, geometry, structures and kinematics are still debated with several recent yet conflicting studies. We have reconsidered the geology of Ikaria to settle the geological and structural context of these plutons. The intrusion depth of the Raches granite has been estimated at 10-15 km by the Al-in-hornblende barometer. Our field study has led to the identification of two major structures: the Gialiskari and Kalamos detachments, which we interpret as belonging to the NCDS. A study of deformation in the granites has highlighted a continuum during cooling that can be described in three stages: i) magmatic deformation, ii) high-temperature ductile deformation from late magmatic stage until complete crystallization of the granite, iii) low-temperature brittle deformation. Throughout this evolution, the same top-to-the-NE shearing deformation was active below the Gialiskari and Kalamos detachments with a progressive localization of strain. A scenario of this deformation continuum below the Gialiskari-Kalamos detachments through the ductile-brittle transition is proposed. The granites were emplaced while the exhumation of the Ikaria high-temperature metamorphic dome was already underway. We conclude that the crustal-scale detachment has controlled the localization of the intrusion and not the opposite.

Laurent, Valentin; Beaudoin, Alexandre; Jolivet, Laurent; Arbaret, Laurent; Augier, Romain; Rabillard, Aurelien

2014-05-01

26

U-Pb conventional dating compared to SHRIMP of the Santa Barbara Granite Massif, Younger Granites Suite of Rondonia, Brazil; Datacoes U-Pb convencional versus SHRIMP do macico estanifero Santa Barbara, Suite Granitos Ultimos de Rondonia, Brasil  

Energy Technology Data Exchange (ETDEWEB)

The Santa Barbara Granite Massif is part of the Younger Granites of Rondonia (998 - 974 Ma) and is included in the Rondonia Tin Province (SW Amazonian Craton). It comprises three highly fractionated metaluminous to peraluminous within-plate A-type granite units emplaced in older medium-grade metamorphic rocks. Sn-mineralization is closely associated with the late-stage unit. U-Pb monazite conventional dating of the early-stage Serra do Cicero facies and late-stage Serra Azul facies yielded ages of 993 +- 5 Ma and 989 +- 13 Ma, respectively. Conventional multigrain U-Pb isotope analyses of zircon demonstrate isotopic disturbance (discordance) and the preservation of inherited older zircons of several different ages and thus yielded a 207 Pb/206 Pb weighted-mean age of 978 +- 13 Ma. The textural complexity of the zircon crystals of the Santa Barbara facies association, the variable concentrations of U, Th and Pb, as well as the mixed inheritance of zircon populations are major obstacles to using conventional multigrain U-Pb isotopic analyses. Sm-Nd model ages and epsilon{sub Nd}(T) values reveal anomalous isotopic data, attesting to the complex isotopic behaviour within these highly fractionated granites. Thus, SHRIMP U-Pb zircon and conventional U-Pb monazite dating methods are the most appropriate to constrain the crystallization age of the Sn-bearing granite systems in the Rondonia Tin Province. (author)

Sparrenberger, Irena [Sao Paulo Univ., SP (Brazil). Inst. de Geociencias. Programa de Pos-graduacao em Recursos Minerais e Hidrogeologia; Bettencourt, Jorge Silva [Sao Paulo Univ., SP (Brazil). Inst. de Geociencias. Dept. de Mineralogia e Geotectonica; Tosdal, Richard M. [Univ. of British Columbia, Vancouver (Canada). Dept. of Earth and Ocean Sciences; Wooden, Joseph L. [Stanford Univ. (United States). Ion Probe Lab.

2002-12-15

27

From explosive breccia to unidirectional solidification textures: magmatic evolution of a phosphorus- and fluorine-rich granite system (Podlesí, Krušné hory Mts., Czech Republic)  

OpenAIRE

The Podlesí granite stock in western Krušné hory Mts. represents the most highly fractionated part of the late Variscan Nejdek-Eibenstock pluton. Internal fabric of the stock has been studied in several boreholes up to 350 m deep. The stock is composed of two tongue-like bodies of albite-protolithionite-topaz granite (stock granite) coalesced at depth, which were emplaced into Ordovician phyllite and biotite granite of younger intrusive complex (YIC) of the Nejdek pluton. The uppermost par...

Breiter K

2002-01-01

28

Age of the Mulcahy Lake intrusion, northwest Ontario, and implications for the evolution of greenstone-granite terrains  

Science.gov (United States)

An investigation of zircon data from the Mulcahy Lake gabbro, a 63 sq km layered mafic intrusion in the Wabigoon subprovince of Ontario, which show that the gabbro crystallized at 2733.2 +1.0, -0.9 Ma, is considered. It is shown that the gabbro intrudes tholeiites of the Crow Lake-Savant Lake greenstone belt. Whole rock samples and mineral separates from the Mulcahy Lake intrusion are dated by Rb-Sr, Sm-Nd, and Ar-30-Ar-40 techniques. Disturbances in the system are revealed by the Rb-Sr data and an initial Sr ratio of 0.7007 for an age of 2733 Ma is indicated by samples with low Rb/Sr ratios. The age determined for the Sm-Nd data is 2744 + or 55 Ma with an epsilon Nd value of +2.6 + or - 1.2 which indicates a source region depleted in a light rare earth element. Primary hornblende is analyzed for Ar-40/Ar-39 and an age of 2703 + or - 20 is obtained. Some implications for the development of greenstone-granite belts are discussed.

Morrison, D. A.; Bogard, D. D.; Phinney, W. C.; Davis, D. W.; Wooden, J. L.; Ashwal, L. D.; MacZuga, D. E.

1985-05-01

29

Incorporation of Model and Parameter Uncertainty in Predicting Radionuclide Fluxes from the Climax Granite Intrusive, Nevada Test Site  

Science.gov (United States)

The Yucca Flat-Climax Mine Corrective Action Unit requires the use of numerical models to predict radionuclide flux rates from three subsurface nuclear tests conducted in a fractured rock mass. Modeling flow and transport in the Climax granite intrusive (CGI) is unique; while attributes of rock fractures have been extensively characterized in subsurface tunnel and drift complexes, information on the saturated flow system, including the position of the water table within the CGI, is largely unknown. A modified version of the Death Valley Regional Flow System (DVRFS) model of Belcher et al. (2004) with refined discretization in the area of the CGI is used to provide boundary conditions and a calibration target for a local-scale stochastic continuum fracture flow and transport model. Uncertainty in the Climax DVRFS model is addressed by including five different geologic framework models, each weighted according to expert elicitation. Five ground water recharge models are then applied to each of the five geologic models, resulting in a total of 25 geologic/recharge models. The CGI fracture flow model consists of 3-D discrete fracture networks, randomly distributed according to probability distribution functions for fracture location, orientation, length and permeability. The networks are directly mapped onto a 3-D finite-difference grid and MODFLOW is used to simultaneously solve for fluid flow within the fracture network and rock matrix. Flow model calibration involved matching the geometric mean of total fluid flux through 200 Monte Carlo fracture network realizations to flux computed in the subsection of the Climax DVRFS model representing the area of the local-scale model domain. By maintaining a constant log_10 mean and variance of fracture conductivity, fracture density was altered until the geometric mean of flux from all 200 network realizations is within +/- 5% of the target flux from the regional model. Variability in flux for individual realizations encompasses 2 to 3 orders-of-magnitude. Weights assigned to individual realizations using a generalized likelihood uncertainty estimation (GLUE) technique reflect this contrast in flux values. A random walk particle method will be used to simulate advection, dispersion, and adsorption and diffusion into the rock matrix using the velocity fields from the flow realizations.

Reeves, D. M.; Pohlmann, K. F.; Pohll, G. M.; Chapman, J. B.; Ye, M.

2006-12-01

30

First report of early Triassic A-type granite and syenite intrusions from Taimyr: product of the northern Eurasian superplume?  

Science.gov (United States)

Ion-microprobe U-Th-Pb analyses of zircon from three high-level syenite-granite stocks in the western part of the Taimyr fold-and-thrust belt have yielded early Triassic ages of 249-241 Ma. Those syenite-granite bodies intrude unmetamorphosed late Paleozoic to early Mesozoic terrigenous and volcanic supracrustal rocks, including the early Triassic Siberian traps. 40Ar- 39Ar isotopic ages of 245-233 Ma correlate well with the ion-microprobe data and define the time of closure for the K-Ar isotopic system. Limited geochemical data for the early Triassic syenite-granite plutons show that they have metaluminous compositions, high potassium, high REE and high LIL concentrations, and 87Sr/ 86Sr and ?Nd ratios intermediate between crust and mantle, suggesting a hybrid mantle-crustal origin. We tentatively suggest that they formed in an anorogenic setting as a result of the Permo-Triassic Euroasian superplume.

Vernikovsky, Valery A.; Pease, Victoria L.; Vernikovskaya, Antonina E.; Romanov, Andrey P.; Gee, David G.; Travin, Alexey V.

2003-01-01

31

Rb-Sr ages of intrusive plutonic rocks from the Stora Le-Marstrand belt in Orust, SW Sweden  

International Nuclear Information System (INIS)

Rb-Sr whole-rock isochrons are reported for the Haelleviksstrand amphibolite (1432 +- 92 Ma) and the Assmunderoed-Myckleby augen granite (1379 +- 46 Ma) which intrude the Stora Le-Marstrand migmatite belt of Orust, SW Sweden. These ages provide a younger limit for the age of the main migmatisation and an older limit for the emplacement of minor silicic and mafic intrusions and subsequent regional metamorphism and deformation. They overlap with published ages from granitic intrusions in the adjacent Amal belt and provide the basis for a correlation between the two belts. (Auth.)

32

The petrogenesis of a wolframite-bearing greisen in the Vykmanov granite stock, Western Krušné hory pluton (Czech Republic)  

OpenAIRE

A wolframite-bearing greisen at Vykmanov, near Ostrov (Czech Republic) occurs at the contact of a small granite stock belonging to the Late Variscan Younger Intrusive Complex (YIC) of the Western Krušné hory/Erzgebirge pluton. The stock emerges as an outcrop of 0.8 × 0.3 km size from a hidden granite body in the eastern continuation of the Nejdek-Eibenstock granite massif. The lens-like greisen body consists mainly of quartz, topaz, protolithionite, and muscovite; it also contains wolframi...

Štemprok M; Pivec E; Langrová A

2005-01-01

33

Genetic relationship between L granite body and 3701 uranium deposit  

International Nuclear Information System (INIS)

The ore deposit occurs in carbonate rocks situated in the exocontact zone (0 - 120 m) with the L granite body. The mineralization is hosted by argillaceous limestone of the middle Devonian Yingtang Formation. The ore bodies are in lenticular or stratifed form. The ores are fine vein-type and disseminated type. Four stages of mineralization in the deposit are recognized. Industrial mineral is pitchblende which occurs as micro-impregnation and micro-vein in the calcite, and fills or replaces its associated minerals. Gangue minerals are chiefly calcite, pyrite, galena, sphalerite, chalcopyrite and tennantite etc. The host rocks of the ore-veins show weak hydrothermal alterations with plane and linear distribution. The L granite body with an area of 238 km2 is a single-stage intrusive batholith which mainly consists of coarse-medium grained biotite granites. Because the urnium mineralization age (65.0 - 30.7 Ma) is much younger than that of the L granite (318 -202 Ma), it may be considered that the deposit is genetically not related to activity of the L granitic magma. However, the granitic rocks may play an important role in the formation of the 3701 uranium deposit in following hands: providing a large number of uranium and lead; providing minor amounts of surfur, carbon and trace elements; forming impermeable basement to promote the accumulation of uranium-bearing solution; providing an additional heat source for heating ore-bearing solution and its convectiting ore-bearing solution and its convective circulation

34

Uranium and thorium distribution in the Contreberg granite, Darling  

International Nuclear Information System (INIS)

Two plutons of young granite, intrusive into other members of the Cape Granite suite, occur to the northwest and southeast of Darling, Western Cape Province. In spite of their comparable temporal and structural positions in the granite series, the two granites differ considerably in textural and compositional properties, making a comparative study desirable. Thus the Contreberg granite was compared with the Klipberg granite. The average radioelement content was lower in the Contreberg granite than in the Klipberg granite. For the Contreberg granite the average values are 6,0 ppm U3O8 and 28 ppm ThO2

35

Timing, petrogenesis and tectonic setting of the Late Paleozoic gabbro-granodiorite-granite intrusions in the Shalazhashan of northern Alxa: Constraints on the southernmost boundary of the Central Asian Orogenic Belt  

Science.gov (United States)

The Late Paleozoic tectonic setting and location of the southernmost boundary of the Central Asian Orogenic Belt (CAOB) with respect to the Alxa Block or Alxa-North China Craton (ANCC) are debated. This paper presents new geochronological, petrological, geochemical and zircon Hf isotopic data of the Late Paleozoic intrusions from the Shalazhashan in northern Alxa and discusses the tectonic setting and boundary between the CAOB and ANCC. Using zircon U-Pb dating, intrusions can be broadly grouped as Late Carboniferous granodiorites (~ 301 Ma), Middle Permian gabbros (~ 264 Ma) and granites (~ 266 Ma) and Late Permian granodiorites, monzogranites and quartz monzodiorites (254-250 Ma). The Late Carboniferous granodiorites are slightly peraluminous and calcic. The remarkably high zircon Hf isotopes (?Hf(t) = + 6-+ 10) and characteristics of high silica adakites suggest that these granodiorites were mainly derived from "hot" basaltic slab-melts of the subducted oceanic crust. The Middle Permian gabbros exhibited typical cumulate textures and were derived from the partial melting of depleted mantle. The Middle Permian granites are slightly peraluminous with high-K calc-alkaline and low ?Hf(t) values from - 0.9 to + 2.9. These granites were most likely derived from juvenile materials mixed with old crustal materials. The Late Permian granodiorites, monzogranites and quartz monzodiorites are characterized as metaluminous to slightly peraluminous, with variable Peacock alkali-lime index values from calc-alkalic to alkali-calcic. These rocks were mainly derived from juvenile crustal materials, as evidenced by their high ?Hf(t) values (+ 3.3 to + 8.9). The juvenile sources of the above intrusions in the Shalazhashan are similar to those of the granitoids from the CAOB but distinct from the granitoids within the Alxa Block. These findings suggest that the Shalazhashan Zone belongs to the CAOB rather than the Alxa Block and that its boundary with the Alxa block can be regarded as the southernmost boundary of the CAOB. The recognition of Late Carboniferous typical adakite magmatism in the region provides evidence for the subduction of the oceanic crust of the CAOB. The Middle-Late Permian magmatisms (266-250 Ma) display a bimodal association with high-K calc-alkaline features and are interpreted as forming in a post-collision setting. These studies, by interaction of regional geology, provide new constraints on the tectonic evolution of the southern CAOB during the Late Paleozoic and the location of the southernmost margin of the CAOB.

Shi, Xingjun; Wang, Tao; Zhang, Lei; Castro, Antonio; Xiao, XuChang; Tong, Ying; Zhang, Jianjun; Guo, Lei; Yang, Qidi

2014-11-01

36

Geochemistry of granitic rocks in Indian cratons, a prelude for uranium exploration  

International Nuclear Information System (INIS)

Peninsular India constitutes Archaean continental nuclei, supercrustals episodic granitic intrusive and effusives, mobile belts and all are welded together by rifts and sutures. The episodic nature of granitic magmatism is well represented with peak ages recorded around 470, 1100, 1800, 2200, 2500, 3100, 3300, 3500 Ma (1) and played a vital role in crustal growth of Peninsular Indian shield similar to the world wide crustal evolution during the Proterozoic times. These cratonic blocks are stabilized and formed basement for Proterozoic basins. This granite related magmatic events include juvenile granites and reactivated gneisses in several parts of the shield areas. These accretions brought metals from mantle and also helped in their remobilization from early formed crustal blocks. Large Ion Lithoplile elements including U, Th and K thus added to the crust, later formed the potential source for QPC, unconformity related uranium deposits. In this paper, geochemical and petrogenetic evolution of granites of Dharwar, Basta, Sighbhum and Bundelkhand cratons of various ages are presented with an emphasis to narrow down the target areas for uranium exploration. The late phase granites of crustal derived with A and S type characters occurring as younger variants in the craton are favourable horizons for uranium exploration. (author)

37

Quartz And Zircon as markers of the magmatic-hydrothermal evolution of the Antônio Vicente Granite, Velho Guilherme Intrusive Suite, Carajás Province  

Directory of Open Access Journals (Sweden)

Full Text Available the Antônio Vicente Granite, Carajás Province, by scanning electron microscope-cathodoluminescence (SEM-CL images. In the lessevolved rocks, containing amphibole and biotite, well developed anhedral to subhedral, luminescent and intensely fractured crystalsdominate, named Qz1. Hydrothermal fluids that percolated the granite modified the magmatic quartz (Qz1 into Qz2 and Qz3 throughprocesses of alteration, dissolution and recrystallization, with these changes much more evident in the intensely altered syenograniterocks. Qz4 constitute medium-to-coarse grained crystals, usually luminescent and comparatively little fractured. Its occurrence is restrictedto strongly hydrotermalized syenogranite rocks and bodies of greisens, suggesting the beginning of the greisenization process.In the greisens, medium-to-coarse grained euhedral, concentrically zoned quartz crystals dominate, with typical features of hydrothermalorigin (Qz5. Fine crystals of zoned cassiterite (? 100 ?m are common and fill cavities in the types Qz4 and Qz5. Zircon crystalsdominantly anhedral, corroded, with the highest contents of Hf and the lower Zr/Hf ratios belong to more evolved and hydrothermallyaltered rocks and to associated greisens, both carriers of Sn mineralization. This fact suggests that the geochemical signature of zircon,especially Zr/Hf ratio, can be used for the preliminary assessment of metallogenic potential of tin granites.

Claudio Nery Lamarão

2013-06-01

38

Petrogenesis of the gold bearing Zarrin granite  

OpenAIRE

Zarrin granite intrusion is located in the Central Iran, to west of Chapedoni and Posht-e-Badam faults. It consists of three separate outcrops situated at the northern end of a long mountain range, which is comprised of Mesozoic rocks. Lithologically the intrusion contains granites as well as, gneisses (?) and aplites. Petrographic and geochemical evidence strongly suggest that they are cogenetic. High aluminum contents and other characteristics of these rocks, as well as petrographic evidenc...

Valizadeh, Mohammed-vali; Omrani, Jafar; Moritz, Robert

2002-01-01

39

Neoproterozoic granitic activities in the Xingdi plutons at the Kuluketage block, NW China: Evidence from zircon U-Pb dating, geochemical and Sr-Nd-Hf isotopic analyses  

Science.gov (United States)

Neoproterozoic igneous rocks are widely distributed in the Kuluketage block along the northern margin of the Tarim Craton. However, the published literature mainly focuses on the ca. 800 Ma adakitic granitoids in the area, with the granites that intrude the 735-760 Ma mafic-ultramafic rocks poorly studied. Here we report the ages, petrography and geochemistry of two granites in the Xingdi mafic-ultramafic rocks, in order to construct a new view of the non-adakitic younger granites. LA-ICP-MS zircon U-Pb dating provided weighted mean 206Pb/238U ages of 743.0 ± 2.5 Ma for the No.I granite (G1) and 739.0 ± 3.5 Ma for the No.II granite (G2). A clear core-rim texture of similar age and a high zircon saturation temperature of ca. 849 ± 14 °C were observed for the No.I granite; in contrast, G2 has no apparent core-rim texture but rather inherited older zircons and a lower zircon saturation temperature of ca. 763 ± 17 °C. Geochemical analysis revealed that G1 is an alkaline A-type granite and G2 is a high-K calc-alkaline I-type granite. Both granites share similar geochemical characteristics of arc-related magmatic rocks and enriched Sr-Nd-Hf isotopes, likely due to their enriched sources or mixing with enriched magma. Whereas G1 and its host mafic rocks form typical bimodal intrusions of the same age and similar Sr-Nd-Hf isotope compositions, G2 is younger than its host mafic rocks and its Sr-Nd-Hf isotope composition indicates a lower crust origin. Although they exhibit arc-related geochemical features, the two granites likely formed in a rift setting, as inferred from thier petrology, Sr-Nd-Hf isotopes and regional tectonic evolution.

Cao, Xiaofeng; Lü, Xinbiao; Yuan, Qian; Wang, Xiangdong; Liu, Hong; Shen, Wen

2014-12-01

40

Interacción termal entre magmas graníticos laramídicos y rocas encajonantes mesoproterozoicas: Historia de enfriamiento de intrusivos de la Sierrita Blanca, NW Sonora / Thermal interaction between Laramide granitic magmas and Mesoproterozoic country rocks: thermochronology of intrusives of Sierrita Blanca, NW Sonora  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish Un estudio termocronológico semi-cuantitativo, combinando técnicas geocronológicas de U-Pb y 40Ar/39Ar, permitió evaluar el fenómeno de cristalización y posterior enfriamiento del cuerpo intrusivo laramídico Sierrita Blanca, así como el efecto termal del mismo en las rocas encajonantes mesoproterozo [...] icas (~1.1 Ga) denominadas granito Murrieta. La disparidad en edades U-Pb en zircones para dos muestras del granito Sierrita Blanca (72.6 ± 1.2 Ma y 69.7 ± 1.0 Ma) pudiera estar asociada al enfriamiento más rápido del magma en la zona de contacto con el encajonante mesoproterozoico; pero no se puede descartar que esta unidad granítica esté compuesta por múltiples intrusiones de composición similar y relativamente espaciadas en el tiempo. Las edades de 40Ar/39Ar (biotita y feldespato potásico) de la muestra de granito más cercana al encajonante son también más antiguas que las de la roca recolectada en la zona más interna del intrusivo. El enfriamiento inicial del granito es relativamente rápido desde la temperatura de cierre del zircón hasta la de la biotita (~36-32°C/Ma), para que posteriormente se pase a enfriamientos relativamente lentos desde la biotita hasta el feldespato potásico (~10-9°C/Ma). Estos enfriamientos del granito Sierrita Blanca son comparables, aunque quizá un poco más lentos, a los estimados para otros granitoides laramídicos del NW de México. Tres muestras del granito mesoproterozoico Murrieta, recolectadas a diferentes distancias del intrusivo laramídico, fueron fechadas por U-Pb en zircones (~1.1 Ga), reiterándose la resistencia de esta sistemática a los efectos termales. Sin embargo, se aprecia la presencia de zircones con pérdida evidente de Pb, que se asocian a la exposición de estas rocas al calor y/o fuidos relacionados a la intrusión laramídica, siendo este efecto más pronunciado en la roca recolectada cerca del contacto con el granito. Este efecto de reajuste isotópico es mucho más marcado para la sistemática de 40Ar/39Ar en biotita y feldespato potásico, al encontrarse estos minerales totalmente reajustados a edades laramídicas. Las estimaciones de enfriamiento post-reajuste isotópico entre biotita y feldespato potásico (~18-15°C/Ma) de las rocas encajonantes son, en cierto modo, armónicas con los enfriamientos estimados para estos mismos minerales en el granito laramídico. Esto sugiere que el enfriamiento general del área de la Sierrita Blanca, después de la intrusión granítica lara-mídica, fue coherente, fnalizando este en las zonas más internas del intrusivo. Por último, destacar que el pulso magmático miocénico presente en la Sierrita Blanca no ha causado ningún efecto termal apreciable en las rocas graníticas cretácicas o mesoproterozoicas. Abstract in english A semi-quantitative thermochronological study, combining U-Pb and 40Ar/39Ar geochronology, has allowed assessment of the crystallization and cooling history of the Laramide Sierrita Blanca granite as well as the thermal effects resulting from the intrusion into the Mesoproterozoic host rocks (~1.1 G [...] a Murrieta granite). The U-Pb zircon age discrepancy between two samples of the Sierrita Blanca granite (72.6 ± 1.2 Ma and 69.7 ± 1.0 Ma) could be explained by a process of faster magma cooling in the contact zone with the host Murrieta granite. However, that the Sierrita Blanca granitic unit was made up of multiple intrusions of similar compositions emplaced relatively close in time cannot be discarded. The 40Ar/39Ar ages of both biotite and K-feldspar for the granite collected close to the contact are also signifcantly older than the ages for the sample collected in a more internal zone of the intrusion. The initial cooling of the Sierrita Blanca granite was fairly fast and monotonous from the closure temperature of zircon to that of biotite (~36-32°C/Ma). Subsequently, the cooling of these Laramide rocks became relatively slow (~10-9°C/Ma) between the closure temperature of biotite and K-f

Mónica A., Enríquez-Castillo; Alexander, Iriondo; Gabriel, Chávez-Cabello; Michael J., Kunk.

2009-12-01

41

El Granito Calasuya: un intrusivo alcalifeldespático postcolisional en el batolito de Sierra Norte-Ambargasta, Córdoba / The Calasuya Granite: a postcollisional alkalifeldspar intrusive in the Sierra Norte-Ambargasta batholith, Córdoba province  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: Spanish Abstract in spanish La zona central del extenso batolito Sierra Norte-Ambargasta, en el bloque más oriental de las Sierras Pampeanas orientales, está representada por granitoides de arco magmático tipo I (granodioritas, monzogranitos, pórfidos dacíticos y riolíticos denominados serie La Isla - Cerro de los Burros), int [...] ruidos por cuerpos menores félsicos postcolisionales, químicamente más evolucionados (denominados unidades Puesto de Los Caminos y Cerro Baritina), todos pertenecientes al Neoproterozoico- Cámbrico inferior. Nueva información geológica y geoquímica de la región centro-oriental del mismo batolito permitió identificar un plutón de composición alcalifeldespática, denominado Granito Calasuya, el primero de esta naturaleza en el batolito. Su mineralogía distintiva la constituyen la composición albítica de la plagioclasa magmática (An Abstract in english The central-western portion of the extended Sierra Norte-Ambargasta batholith, in the easternmost block of the eastern Sierras Pampeanas, is largely characterized by pre-collisional I-type magmatic arc granitoids (granodiorites, monzogranites, dacite and rhyolite porphyries named La Isla - Cerro de [...] los Burros series), and by smaller sized postcollisional felsic intrusives of higher evolved chemistry (named Puesto de los Caminos and Cerro Baritina units), all of which crystallized along the Late Proterozoic -Lower Cambrian time span. New geological and geochemical data from the central and oriental areas of the batholith allowed to identify an intrusive body of alkalifeldspar composition (the Calasuya granite), the first of its type in the batholith. Its distinctive mineralogy is highlighted by the albitic composition of magmatic plagioclase (molar An

Javier, Elortegui Palacios; Raúl, Lira; Fernanda, Poklepovic; Michael J., Dorais.

2008-09-01

42

Structure and emplacement of granite plutons in the Paleoproterozoic crust of Eastern Burkina Faso: rheological implications  

Science.gov (United States)

The Fada N'Gourma area in Burkina Faso is underlain by Paleoproterozoic rocks that make the northeastern West-African Craton. This region is composed of NE-trending volcano-sedimentary belts and foliated tonalites, affected by several shear zones. A generation of younger, ˜2100 Ma-old, non-foliated biotite-bearing granites intrudes the former rock units. We have investigated the younger granite pluton of Kouare that was previously considered as forming a single body with the pluton of Satenga to the west, a pluton which likely belongs to the ˜20 Ma more recent Tenkodogo-Yamba batholith. Magnetic fabric measurements have been combined with microstructural observations and the analysis of field and aeromagnetic data. The granite encloses angular enclaves of the host tonalites. Magmatic microstructures are preserved inside the pluton and solid-state, high-temperature deformation features are ubiquitous at its periphery. The presence of steeply plunging lineations in the pluton of Kouare and its adjacent host-rocks suggests that large volumes of granitic magmas became crystallized while they were ascending through the crust that was softened and steepened close to the contact. Around Kouare, the foliation in the host tonalites conforms with a map-scale, Z-shaped fold in between NNE-trending shear zones, implying a bulk clockwise rotation of the material contained in-between the shear zones, including the emplacing pluton. Regionally, the Fada N'Gourma area is concluded to result from NW-shortening associated with transcurrent shearing and vertical transfer of granitic magmas. This study concludes that the ˜2200 Myears old juvenile crust of Burkina Faso was brittle before the intrusion of the biotite-granites, became softened close to them and that gravity-driven and regional scale wrench tectonics were active together.

Vegas, Nestor; Naba, Seta; Bouchez, Jean Luc; Jessell, Mark

2008-11-01

43

Petrophysical and geochemical characteristics of late Variscan granites in the Karlovy Vary Massif (Czech Republic - implications for gravity and magnetic interpretation in shallow depths  

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Full Text Available The Karlovy Vary Massif (KVM in northern Bohemia is a composite granite body built up of Late Variscan biotite, two mica and lithium mica granites. We summarize the available whole-rock geochemical and petrological data and correlate them with similar information from three boreholes in the northern and southwestern parts of the Massif. The aim of the study was to determine whether various types of granites differ in their physical and chemical properties, and whether any differences in physical characteristics affect the accuracy of geophysical interpretation. In accord with the earlier studies, we distinguish two geochemically and petrophysically contrasting granite suites - the Older Intrusive Complex (OIC and Younger Intrusive Complex (YIC. The geochemical data show that the OIC and YIC granites differ significantly in the content of most major-element oxides (like SiO2, TiO2, FeO, Fe2O3tot, MgO and CaO. As to physical parameters, the granites differ markedly in magnetic susceptibilities and in the contents of radioactive elements (U and Th. From gravity and magnetic data we compiled a 22 km long geophysical profile, which crosses two of the three studied boreholes. For the construction of geological model along this profile, we used the data on the petrophysical properties measured on samples from the boreholes. Densities of the individual granite types are very similar to each other and thus the distinction of the OIC and YIC granites based on gravity data is not possible. Magnetic susceptibility differs markedly for the OIC and YIC granites in the drill logs, but absolute values of magnetic susceptibilities are very low. Modelling showed that neither gravimetry nor magnetometry are suitable methods for distinguishing between the different types of granites. On the other hand, it proved that the spatial distribution of individual granite intrusions does not affect the overall interpretation of the shape, size and depth of the whole granite body.

Blecha V

2012-07-01

44

Granite genesis  

CERN Document Server

Provides a synthesis of current ideas of granite genesis in the earth's crust developed over the last 20 yearsProvides an alternative model for granite genesis and a reinterpretation of current ideasHighlights results of Chinese research (published in Chinese) over the last 30 years in English for the first time

Chen, Guo-Neng

2007-01-01

45

From explosive breccia to unidirectional solidification textures: magmatic evolution of a phosphorus- and fluorine-rich granite system (Podlesí, Krušné hory Mts., Czech Republic  

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Full Text Available The Podlesí granite stock in western Krušné hory Mts. represents the most highly fractionated part of the late Variscan Nejdek-Eibenstock pluton. Internal fabric of the stock has been studied in several boreholes up to 350 m deep. The stock is composed of two tongue-like bodies of albite-protolithionite-topaz granite (stock granite coalesced at depth, which were emplaced into Ordovician phyllite and biotite granite of younger intrusive complex (YIC of the Nejdek pluton. The uppermost part of the intrusion is bordered by a layer of marginal pegmatite (stockscheider up to 50 cm thick. Explosive breccia was found as an isolated block at the southwest contact of the stock. It is comprised of fragments of phyllite several millimetres to 5 cm in size cemented with fine-grained granitic matrix similar to the stock granite, but very fine-grained.
Within the uppermost 100 m, the stock granite is intercalated with several mostly flat-lying dykes of albite-zinnwaldite-topaz granite (dyke granite. Upper and lower contacts of the dykes are sharp, flat, but in detail slightly uneven. The thickest dyke (about 7 m outcrops in an old quarry. A prominent example of layering with unidirectional solidification textures (UST was found in the upper part of this major dyke. Individual Q-Afs laminae are separated by comb quartz layers and/or by layers of oriented fan-like zinnwaldite aggregates. A pegmatite-like layer with oriented megacrysts of Kfs up to 6 cm long was encountered in the uppermost part of the dyke. One thin layer of fine-grained quartz with oriented Kfs-megacrysts was found within the stock granite.
Post-magmatic processes, particularly greisenisation, developed only to a limited degree. The uppermost flat dyke of the dyke granite was partly greisenised into white quartz-rich (+topaz, Li-mica, wolframite greisen. Scarce thin, steep stringers of biotite greisen were encountered over the entire outcrop and in drilled parts of the stock granite and surrounding biotite granite.

Breiter K

2002-06-01

46

The search for the youngest granites in the southern part of the Natal Metamorphic Province  

International Nuclear Information System (INIS)

It is clear that the Belmont Pluton and the dykes are geochemically, isotopically and therefore, genetically distinct. The Belmont pluton is probably related to the garnet leucogranite phase of the Margate Complex. It is suggested that the dykes (? 965 Ma) are younger than the Belmont pluton (?1055 Ma). The relatively low initial 87Sr/86Sr are typical of the granites intruded at ?1000 Ma. The age of the dykes is comparable with the 951 ± 16 Ma (Ro=.70320 ± 13) given for the Sezela pluton. The high Ro (?0.715) of the dykes is similar to other, minor granite sheets from southern Natal, and is compatible with an origin by late-stage melting of pre-existing radiogenic material. Both the dykes and the Sezela pluton are unequivocally younger than the D3 deformation, whereas the young dates from the Oribi Gorge Suite are controversial. Thus, although it is possible that some of the minor, intrusive granitic sheets could yet be shown to be of Pan-African age, it is evident that no significant Pan-African magmatism or thermal overprinting has affected the Natal sector of the Namaqua-Natal-Maudheim belt. 1 fig., 7 refs

47

The petrogenesis of a wolframite-bearing greisen in the Vykmanov granite stock, Western Krušné hory pluton (Czech Republic  

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Full Text Available A wolframite-bearing greisen at Vykmanov, near Ostrov (Czech Republic occurs at the contact of a small granite stock belonging to the Late Variscan Younger Intrusive Complex (YIC of the Western Krušné hory/Erzgebirge pluton. The stock emerges as an outcrop of 0.8 × 0.3 km size from a hidden granite body in the eastern continuation of the Nejdek-Eibenstock granite massif. The lens-like greisen body consists mainly of quartz, topaz, protolithionite, and muscovite; it also contains wolframite (ferberite and native bismuth mineralization. It was formed by replacement of a medium-grained, equigranular, slightly porphyritic Li-F granite of the Karlovy Vary pluton characterized by weak postmagmatic albitization and pervasive muscovitization. The greisen is geologically and compositionally transitional between the Li-rich greisens in albite granites (e.g. with zinnwaldite such as at Krásno and the Li-poor greisens (e.g. phengite greisens at Gottesberg and P?ebuz associated with weakly albitized granites of the Younger Intrusive Complex. The Vykmanov greisen formed in a subsolidus stage of granite evolution by progressive alkali loss and fluorine metasomatism, leading to the formation of Li-mica quartz greisen subsequently replaced by topaz-quartz greisen at the granite/crystalline contact. These greisens were affected by late-stage muscovitization and argillitization (sericitization, the formation of clay minerals. The Li-Fe mica composition of the greisens corresponds to protolithionite (lithian siderophyllite and is similar to the composition of micas in the enclosing granite. The tungsten-bearing greisenization represents a postmagmatic episode in the development of the Krušné hory/Erzgebirge batholith, and is located at the eastern contact of highly evolved YIC granites of the Western Krušné hory pluton. The greisen formed from CO2 -poor hydrothermal solutions, at about 400 °C, which evolved from highly saline brines as evidenced by fluid inclusion studies. The geological situation suggests that the mineralizing fluids were mostly magmatic and were responsible for the tungsten-bismuth specialization of the greisens, whereas meteoric waters participated in mineralization during later stages.

Štemprok M

2005-09-01

48

Petrology, Geochemistry and Tectonomagmatic Setting of Neshveh Intrusion (NW Saveh)  

OpenAIRE

Neshveh intrusion is located in the NW of Saveh City and is a part of Orumieh-Dokhtar magmatic arc. This intrusion consists of quartz monzodiorite, granodiorite and granite that have intruded into the Eocene volcano-sedimentary rocks. This intrusion is high-K calk-alkaline and metaluminous and is classified as I-type granitoids. Field investigations along with petrographic and geochemical studies indicate that all phases of Neshveh intrusion are derived from a common ma...

Reza Keshavarzi; Dariush Esmaili; Mehdi Rezaei Kahkhaei; Mir Ali Asghar Mokhtari; Reza Jabari

2014-01-01

49

Ad Duwayhi, Saudi Arabia: Geology and geochronology of a neoproterozoic intrusion-related gold system in the Arabian shield  

Science.gov (United States)

The Ad Duwayhi gold deposit, located in the east-central part of the Arabian shield, is the newest gold discovery in Saudi Arabia. Exploration to date has identified a gold resource of greater than 1 million ounces (oz) with significant potential for expansion. Gold mineralization was closely associated, in time and space, with emplacement of a late- to postorogenic, intracrustal, northwest-oriented granite body (659 ?? 7 Ma) and comagmatic square quartz porphyry (646 ?? 11 Ma), a hypabyssal and perhaps younger phase of the granite. Mineralization was largely confined to northeast-striking, southeast-dipping fault zones. Hydrothermal alteration consisted of early biotitic alteration overprinted by sericitic alteration. Sericitic alteration was coincident with gold mineralization and produced a quartz-sericite-carbonate-pyrite-rutile mineral assemblage, found both as vein fill and wall-rock alteration products. Mineralization styles, in the following general paragenetic sequence, include (1) quartz-molybdenite veins in and near the granite stock, (2) low-grade gold-bearing quartz vein breccia in and along the margins of the granite stock, (3) gold-bearing stockwork and sheeted quartz veins, and (4) massive to banded gold-rich tabular quartz veins. The gold-bearing stockwork, sheeted, and tabular veins are generally spatially associated with square quartz porphyry dikes and more distal to the granite stock. Mineralized zones at Ad Duwayhi are characterized by low sulfide and base metal content and gold/silver ratios of approximately 6/1. Gold shows no significant correlation with other metals, except lead, and moderate correlation with silver. Re-Os dating of molybdenite from a quartz-molybdenite vein and a tabular quartz vein with cogenetic gold produced robust ages of 655.6 ?? 2.7 and 649.9 ?? 2.3 Ma, respectively, documenting that gold mineralization and crystallization of granite and square quartz porphyry were, within uncertainty, coeval events. This age correlation combined with granite textural features, the presence of unidirectional solidification textures in granite and square quartz porphyry, and the nature and time-space distribution of mineralization styles, all indicate that mineralization evolved in and near the interface between a crystallizing magma and the surrounding rocks and, thus, is consistent with an intrusion-related genesis. In light of our findings at Ad Duwayhi, a reassessment of similar intrusion-hosted deposits in the Arabian shield is warranted, and areas of late- to postorogenic plutonism, particularly in the Afif composite terrane, should be considered prospective for intrusion-related gold systems. ??2004 by Economic Geology.

Doebrich, J.L.; Zahony, S.G.; Leavitt, J.D.; Portacio, J.S., Jr.; Siddiqui, A.A.; Wooden, J.L.; Fleck, R.J.; Stein, H.J.

2004-01-01

50

Petrographic and mineralogical features of the uraniferous pink granites in the north eastern desert of egypt  

International Nuclear Information System (INIS)

The present work is concerned with the petrological, mineralogical and geochemical studies of some uranium bearing younger granites in the north eastern desert of egypt particularly Gebel Gattar area. The area around Gebel Gattar comprises the following rock units (starting from the oldest): meta volcanic, diorite-grano-diorite complex- Dokhan volcanics- Hammamat sediments, younger granites and dykes. The most significant structural features are represented by NNE-ENE dominantly trending faults and joints. Petrographicaly, the pink granites are divided into normal and mineralized (uraniferous) granites. Normal granites are classified into three types; a) leucocratic perthitic granite, b) hornblende- biotite perthitic granite and c) two feldspars perthitic granite. Mineralized granites are sheared, deformed, pinkish brown in colour and strongly altered. A remarkable secondary uranium mineralization has been recorded along fault and fracture zones

51

Analysis of microporous structure in granite  

International Nuclear Information System (INIS)

The water saturation method and the mercury intrusion porosimetry were applied to the characterization of micropores in granite. Although these techniques have been commonly used to characterize pores in rocks, special cares are needed for precise measurement of the porosity and the pore size of low-porosity rocks. The water saturation method uses water-saturated weight, submerged weight and dry weight of the rock samples to calculate the porosity. The errors accompanied in the measurements of the water-saturated weight often bring about significant errors in determination of the porosity. Analysis of drying curves of water-saturated weight enabled precise measurements of porosity. In the mercury intrusion porosimetry, a major part of the error in the porosity determination is due to rough surfaces of the sample. For the porosity determination described in this paper, the rock sample was cut into rectangular parallelepipeds, instead of crushing, to reduce the surface roughness. The detection limit of the mercury intrusion is also a cause for the error for low-porosity samples. Five samples whose total volume was 6ml were simultaneously put in the measurement cell of the porosimeter to increase the amount of intruding mercury. These effort made reliable characterization of pores in a granite from Inada, Ibaraki, Japan and pores in a granite from the Underground Research Laboratory (URL) of Atomic Energy of Canada Limited, Manitoba, Canada. The distribution of the pore oba, Canada. The distribution of the pore diameter of these granites were nearly logarithmic normal. The porosity of Inada granite was determined to be (0.49±0.07)% with the modal diameter of 160nm. The micropores of a few tens to a few hundred nanometers in width were observed by SEM. The URL granite had the porosity of (0.40±0.10)% and the modal diameter of 340nm. The assumptions in applying the Fickian diffusion theory to the diffusion of ions in porous materials were confirmed for these granites. (J.P.N.)

52

Maurim intrusive suite: a calc-alkacic batholite zoned of catarinense shield  

International Nuclear Information System (INIS)

The geological survey of the Florianopolis Sheet (SG.22-Z-D-V) identified and characterized a calc-alkacic multi-intrusive and polydiapiric suite that occurs as a granitic batholite roughly concentric in texture and composition. This co-magmatic plutonic sequence is intrusive in the granite-gneissic basement of amphibolite facies, with which it was formerly confounded. The initial magmatic terms, put-in-place at the marginal portions of the batholite, are represented by quartz-diorites and tonalites (Forquilha Tonalites), followed by granodiorites (alto da Varginha Granodiorite), granodiorites to monzonites (Rio das Antas Granite) and completed by an inner portions of porphyritic monzonites (Sao Pedro de Alcantara Granite). The identifications of the compositional zoning that results from the development of the magmatic chamber is based on the examination of 74 rock samples that were analysed for major and minor oxides and trace elements (Ba, F, Li, Mo, Sn, W, Y, Rb, Nb, Zr and Sr). The treatment of these data shows the portions where mantle fractions predominate as well as the others where crustal meltings dominate, what demonstrates an origin by in situ differentiation processes, fractioning and different degrees of magmatic mixing. Geochronologic dating by Rb/Sr, K/Ar and U/Pb methods show isochronic and conventional ages of 600 to 700 m.y. that roughly are in accord with the temporal progress towards the younger felsic phases, putting this suite in the Upper Proterozoic age. The initial Sr sup(87) / Sr sup(86) ratios, around 0.710, point to a crustal origin with variable mantle contribution to these rocks. (author)

53

The uranium, thorium and molybdenum distribution in selected leucogranites of the Cape-granite-suite  

International Nuclear Information System (INIS)

Younger intrusions and hydrothermally altered rocks like alkali granite, alaskite, syenite and episyenite resembling uranium ore deposits in France and the Roessing ore body in SWA/Namibia are found within the Saldanha and Darling batholiths of the south-western Cape Province. Two areas were geologically mapped in detail and surveyed with a portable gamma spectrometer in order to establish the regional variation in U and Th concentration. A quantitative study of alpha particle tracks on autoradiographs of selected thin sections led to the determination of the contributions by various minerals to the U and Th content of each individual rock type. The rocks were also investigated petrologically and geochemically with special attention to secondary alteration processes that could have played a part in causing the distribution pattern of U and Th. Radioelement analyses of 45 mineral separates and 51 whole rock analyses were utilised

54

Uranium in granites  

International Nuclear Information System (INIS)

Recent research activities of the Canadian Uranium in Granites Study are presented in 18 papers and 3 abstracts. 'Granites' is used as a generic term for granitoids, granitic rocks, and plutonic rocks

55

Rb-Sr and Pb-Pb geochronological studies on the granite gneiss of Kuilapal, Purulia-Bankura Midnapore district, West Bengal  

International Nuclear Information System (INIS)

The number of younger granite plutons intruding the Singhbhum Mobile Belt (SMB) surrounding the Singhbhum-Orissa Craton, viz. Kuilapal granite on the East, Mayurbhanj granite, Soda granite, Arkasoni granite, Chakradharpur granite gneiss and Tamper kola granite on the west. Of these Kuilapal granite body is the largest. Besides small granite bodies intruding the low-grade meta sediments and meta volcanics which occur north of the Dalma volcanic belt. Petrographic and geochemical characters of the minor granite bodies south of Dalma volcanics are similar to those of Kuilapal granite, which is inferred to have been produced by shallow-level fractional crystallisation of a crustally derived granodiorite melt. Dominance of xenoliths in the Kuilapal granite suggest large-scale assimilation of crustal rocks. The radiometric ages vis-a-vis isotope geochemistry of the various granitoid plutons occurring within the mobile belt were used to constrain the evolutionary history of the SMB supracrustals. The Singhbhum Shear Zone which marks the boundary of the SMB with Singhbhum-Orissa Craton, shows multiple reactivation, the oldest being at ? 3.09Ga. Further phases of granite plutonism and/or shearing and mineralisation have been reported along this shear zone occurred in Palaeo-to Mesoproterozoic periods at ? 2.2, 1.8, 1.6-1.5, 1.4 and 1.0 Ga respectively. The present work pertains to the Rb-Sr and Pb-Pb whole rock geochronological studies on Kuilapal granite, which are intrus on Kuilapal granite, which are intrusive into the metasediments of Singhbhum group in the tectonic setup of north Singhbhum Mobile Belt. Fourteen samples were collected, finely powdered form the homgenised representative which were processed further. The dissolution of the rock carried out in a class-100 clean chemical laboratory, followed by the elemental separation using exchange chromatography. The separated pure fractions of the elements were analysed on VG354 Thermal Ionisation Mass spectrometer for their isotopic ratios. The Rb-Sr data on ten samples define an isochron age of 1792±98 Ma, with an initial 87Sr/86Sr of 0.7064±0.0069 (MSWD = 13). The Pb isotopic data on these samples define a Pb-Pb isochron age of 1863 ± 80Ma (MlSWD =11.3) with a model ?1 value of 8.53±0.27. Both the Rb-Sr and the Pb-Pb ages are in agreement within the limits of experimental errors. Since the 87Sr/86Sr initial ratio and model ?1 value are higher than the contemporary mantle sources, the data indicate involvement of enriched crustal sources. This age obtained on Kuilapal granite can be taken as the age of one of those periods of reactivation which occurred during Palaeo-to Mesoproterozoic periods. (author)

56

Determination of concentrations and isotopic ratio of uranium in groundwaters drawn from two deep wells drilled in granitic rocks belonging to Itu intrusive suite; Determinacao das concentracoes e razoes isotopicas de uranio em aguas subterraneas extraidas de pocos perfurados em rochas da suite intrusiva de Itu (SP)  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the first results obtained in the determination of dissolved uranium concentrations and ({sup 234}U/{sup 238}U) activity ratios of groundwaters drawn from two deep wells drilled in granitic rocks belonging to Itu Intrusive Suite, which is located at eastern Sao Paulo State. One of the wells, whose groundwaters have been analyzed, is located in Salto Town, while the other one is located in Itu Town. The groundwater sampling is monthly and begun on September, 2004, in order to investigate possible sazonal variations. The alpha spectrometry technique, associated with isotopic dilution method, has been used for these determinations. The data obtained up to now show that the groundwaters from Salto present uranium concentrations significantly lower ((0.098 {+-} 0.007) - (0.17 {+-} 0.01) ng/g) than those from Itu ((0.22 {+-} 0.02) - (0.31 {+-} 0.02) ng/g). The {sup 234}U and {sup 238}U isotopes of the investigated groundwaters from both wells are in radioactive disequilibrium, with ({sup 234}U/{sup 238}U) activity ratios systematically higher than unity. Although the groundwaters from Salto well are characterized by low {sup 234}U and {sup 238}U specific activities they present higher ({sup 234}U/{sup 238}U) activity ratios than those from Itu. The observed differences on the behavior of uranium concentrations and ({sup 234}U/{sup 238}U) activity ratios in the groundwaters from the two wells are very probably due to the large variety of granitic rocks from Itu Intrusive Suite, which are characterized by distinct uranium abundances. (author)

Souza, Francisca de; Reyes, Erika; Marques, Leila Soares [Sao Paulo Univ., SP (Brazil). Inst. de Astronomia, Geofisica e Ciencias Atmosfericas. Dept. de Geofisica]. E-mail: francisca@iag.usp.br; erika@iag.usp.br; leila@iag.usp.br

2005-07-01

57

Special features of the accessory mineralization of the ore-bearing light-granite formation of the Southern Pamir  

International Nuclear Information System (INIS)

In the article was examined the distribution of the accessory minerals in six intrusive complexes, which relate to one light-granite formation type. According to the elementary sign, all accessory minerals of the light-granite formation of the Southern Pamir are classified to nine groups. It is compared the accessory minerals of the Southern Pamir with the accessory minerals of the light-granites of other regions. The connection between the accessory minerals of intrusive complexes and the mineralization are shown

58

2005 dossier: granite; Dossier 2005: granite  

Energy Technology Data Exchange (ETDEWEB)

This document makes a status of the researches carried out by the French national agency of radioactive wastes (ANDRA) about the geologic disposal of high-level and long-lived radioactive wastes in granite formations. Content: 1 - advantage of granitic formations for the geologic disposal; 2 - containers; 3 - design study of a disposal facility in granitic environment; 4 - understanding and modelling of granite; 5 - description of disposal concepts in granitic environment; 6 - long-term and safety aspects; 7 - conclusion. (J.S.)

NONE

2005-07-01

59

Tectono-magmatic evolution of the younger Gardar southern rift, South Greenland  

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Full Text Available The 1300–1140 Ma Gardar period in South Greenland involved continental rifting, sedimentation and alkaline magmatism. The latest magmatism was located along two parallel rift zones, Isortoq–Nunarsuit in the north and the Tuttutooq–Ilimmaasaq–Narsarsuaq zone in the south addressed here. The intrusive rocks crystallised at a depth of <4 km and are essentially undisturbed by later events. Magmatism in the southern zone began with the emplacement of two giant, ?800 m wide dykes and involved intrusion of transitional olivine basaltic, high Al/Ca magmas crystallising to troctolitic gabbros. These relatively reduced magmas evolved through marked iron enrichment to alkaline salic differentiates. In the Older giant dyke complex, undersaturated augite syenites grade into sodalite foyaite. The larger, c. 1163 Ma Younger giant dyke complex (YGDC mainly consists of structureless troctolite with localised developments of layered cumulates. A layered pluton (Klokkenis considered to be coeval and presumably comagmatic with the YGDC. At the unconformitybetween the Ketilidian basement and Gardar rift deposits, the YGDC expanded into a gabbroic lopolith. Its magma may represent a sample from a great, underplated mafic magma reservoir, parental to all the salic alkaline rocks in the southern rift. The bulk of these are silica undersaturated; oversaturated differentiates are probably products of combined fractional crystallisation and crustalassimilation.A major dyke swarm 1–15 km broad was intruded during declining crustal extension, with decreasing dyke widths and increasing differentiation over time. Intersection of the dyke swarm and E–W-trending sinistral faults controlled the emplacement of at least three central complexes (Narssaq, South Qôroq and early Igdlerfigssalik. Three post-extensional complexes (Tugtutôq,Ilímaussaq and late Igdlerfigssalik along the former rift mark the end of magmatism at c. 1140 Ma. The latter two complexes have oblate plans reflecting ductile, fault-related strain. The Tugtutôqcomplex comprises quartz syenites and alkali granites. The Ilímaussaq complex mainly consists of nepheline syenite crystallised from highly reduced, Fe-rich phonolitic peralkaline (agpaitic magma,and resulted in rocks with very high incompatible element concentrations.Abundant anorthositic xenoliths in the mafic and intermediate intrusions point to a large anorthosite protolith at depth which is considered of critical importance in the petrogenesis of the salicrocks. Small intrusions of aillikite and carbonatite may represent remobilised mantle metasomites. The petrological similarity between Older and Younger Gardar suites implies strong lithospheric control of their petrogenesis. The parental magmas are inferred to have been derived from restitic Ketilidian lithospheric mantle, metasomatised by melts from subducting Ketilidian oceanic crust and by small-scale melt fractions associated with Gardar rifting.There are numerous analogies between the southern Gardar rift and the Palaeogene East Africanrift.

Brian G.J. Upton

2013-11-01

60

Melting granites to make granites  

Science.gov (United States)

Large-scale partial melting in the continental crust is widely attributed to fluid-absent incongruent breakdown of hydrous minerals in the case of pelites, greywackes and meta-mafic rocks. Granite is a far more common rock in the continental crust, but fluid-absent hydrate-breakdown melting is unlikely to result in significant melting in granites because of their low modal abundance of mica or amphibole. Experiments show that fluid-present melting can produce ~30% melt at low temperatures (690°C). Thus, granites and leucogranites can be very fertile if H2O-present melting occurs via reactions such as plagioclase + quartz + K-feldspar + H2O = melt, because of their high modal proportions of the reactant phases. Our study investigates the Kinawa Migmatite in the São Francisco Craton, southeastern Brazil. This migmatite is derived from an Archaean TTG sequence and can be divided into; 1) pink diatexites, 2) leucosomes, 3) grey gneisses and 4) amphibolites. The migmatite records upper-amphibolite to beginning of granulite facies metamorphism in a P-T range from 5.1-6.6 kbar and ~650-780°C. Pink diatexites are the most abundant rocks, and their appearance varies depending on the amount of melt they contained. Three types are recognised: residual diatexites (low melt fraction (Mf)), schlieren diatexites (moderate Mf) and homogeneous diatexites (high Mf). They are very closely related spatially in the field, with mostly transitional contacts. There is a sequence with progressive loss of ferromagnesian minerals, schollen and schlieren through the sequence to the most melt-rich parts of the diatexites as magmatic flow became more intense. There are fewer ferromagnesian minerals, thus the melt becomes cleaner (more leucocratic) and, because the schlieren have disaggregated the aspect is more homogeneous. These parts are texturally similar to leucogranites in which the biotite is randomly distributed and pre-melting structures are completely destroyed. The likely protolith for the migmatites was a leucocratic granodiorite (with modal K-feldspar up to 30% and biotite up to 5%), and from geochemical modelling the degree of partial melting ranged from 0.21 to 0.25. Furthermore, the residual diatexites show a complementary low modal proportion, or even absence, of K-feldspar, but an increase in modal plagioclase, quartz (up to 56 and 37% respectively) and biotite (5-16%). This suggests that the melting reaction did not involve biotite and that plagioclase and quartz were in excess. As result the melt generated is fairly leucocratic, and most of the mafic phases in it are inherited. Anatectic melts in the Kinawa Migmatite were mildly metaluminous and distinctly leucocratic (A/CNK from 0.97 to 1.01; SiO2 from 72.8 to 75.65%; (FeOT+MgO+TiO2) from 0.49 to 2.3%). Since most granites have a higher (FeOT+MgO+TiO2), additional processes must add the "mafic component" to these melts before they form plutons.

Carvalho, Bruna B.; Sawyer, Edward W.; Janasi, Valdecir de A.

2014-05-01

61

Review of engineering, hydrogeological and vadose zone hydrological aspects of the Lanseria Gneiss, Goudplaats-Hout River Gneiss and Nelspruit Suite Granite (South Africa)  

Science.gov (United States)

Three major basement granites of South Africa, viz. the Lanseria Gneiss of the Johannesburg Dome Granite, the Goudplaats-Hout River Gneiss and the Nelspruit Suite, are compared in terms of existing and new geotechnical and hydrogeological data. Typical weathering profiles based on landform and climate are deduced, denoting typical engineering and hydrogeological behaviour. Finally, the vadose zone behaviour of the basement granites are described with the aim on better understanding of the behaviour of these systems under variable saturation. Ephemeral hillslope wetlands, seepage lines and catenas are specifically addressed as associated hydrological influences, as well as the associated processes of translocation forming duplex soils and pedogenesis forming ferricrete. The final summarised findings depict low plasticity and expansiveness of granites with the most notable geotechnical influences being collapsibility, dispersive behaviour, seepage and difficult excavation. Hydrologically, secondary porosity prevails and younger structures or intrusions govern groundwater occurrence. The vadose zone comprises thick fractured rock to be included in modelling with the soil zone having saturated conductivity typically in the order of 1 × 10-4 to 1 × 10-5 m/d.

Dippenaar, Matthys A.; van Rooy, J. Louis

2014-03-01

62

Nature of the Yucatan Block Basement as Derived From Study of Granitic Clasts in the Impact Breccias of Chicxulub Crater  

Science.gov (United States)

The tectonic and petrologic nature of the basement of the Yucatan Block is studied from analyses of basement clasts present in the impact suevitic breccias of Chicxulub crater. The impact breccias have been sampled as part of the drilling projects conducted in the Yucatan peninsula by Petroleos Mexicanos, the National University of Mexico and the Chicxulub Scientific Drilling Project. Samples analyzed come mainly from the Yaxcopoil-1, Tekax, and Santa Elena boreholes, and partly from Pemex boreholes. In this study we concentrate on clasts of the granites, granodiorites and quartzmonzonites in the impact breccias. We report major and trace element geochemical and petrological data, which are compared with data from the granitic and volcanic rocks from the Maya Mountains in Belize and from the Swannee terrane in Florida. Basement granitic clasts analyzed present intermediate to acidic sub-alkaline compositions. Plots of major oxides (e.g., Al2O3, Fe2O3, TiO2 and CaO) and trace elements (e.g., Th, Y, Hf, Nb and Zr) versus silica allow separation of samples into two major groups, which can be compared to units in the Maya Mountains and in Florida basement. The impact suevitic breccia samples have been affected by alteration likely related to the hydrothermal processes associated with the crater melt sheet. Cloritization, seritization and fenitization alterations are recognized, due to the long term hydrothermalism. Krogh et al. (1993) reported U-Pb dates on zircons from the suevitic breccias, which gave dates of 545 +/- 5 Ma and 418 +/- 6 Ma, which were interpreted in terms of the deep granitic metamorphic Yucatan basement. The younger date correlates with the age for the Osceola Granite and the St. Lucie metamorphic complex of the Swannee terrane in the Florida peninsula. The intrusive rocks in the Yucatan basement may be related to approx. 418 Ma ago collisional event in the Late Silurian.

Vera-Sanchez, P.; Rebolledo-Vieyra, M.; Perez-Cruz, L.; Urrutia-Fucugauchi, J.

2008-05-01

63

Geochronology of granitic rocks from the Ruangwa region, southern Tanzania - Links with NE Mozambique and beyond  

Science.gov (United States)

New U-Pb zircon LA-ICP-MS data are presented for 4 granitoid bodies which intrude high grade gneisses of the previously unmapped Ruangwa region in southern Tanzania. The study area forms part of the late Neoproterozoic East African Orogen (EAO). The oldest unit, a coarse-grained migmatitic granitic orthogneiss gave an early Neoproterozoic (Tonian) crystallization age of 899 ± 9/16 Ma, which is similar to, but significantly younger than, Stenian-Tonian basement ages in areas relatively nearby. Crust of this age may extend as far north as the major Phanerozoic Selous Basin, north of which Archaean protolith ages predominate (the "Western Granulites"), except for the juvenile Neoproterozoic "Eastern Granulites", which are not represented in the study area. To the south, the Tonian crust of the study area provides a tentative link with the Marrupa Complex in NE Mozambique. A granite pluton, dated at 650 ± 5/11 Ma is broadly coeval with the main Pan-African tectono-thermal event in the East African Orogen that is recorded across Tanzania north of the Selous Basin. Zircons in this granite contain inherited cores at ca. 770 Ma. This age is within the range of dates obtained from south and west of the study area from juvenile granitoid orthogneisses which might be related to a widespread, but poorly understood, early phase of Gondwana assembly along an Andean-type margin. South of the study area, in NE Mozambique, the latest orogenic events occurred at ca. 550 Ma, and are sometimes attributed to the Ediacaran-aged "Kuunga Orogeny". While metamorphic dates of this age have been recorded from the EAO north of the Selous Basin, magmatic rocks of this event have not been recognized in Tanzania. The two youngest granitoids of the present study are thus the first 500-600 Ma igneous rocks reported from the region. A weakly deformed very coarse-grained granite pluton was dated at 591 ± 4/10 Ma, while a very late, cross-cutting, undeformed granite dyke gave an intrusive age of 549 ± 4/9 Ma. The granitoids ages presented in this study contain elements that are characteristic of the northern, Tanzania-Kenya, segment of the East African Orogen and of the southern, Mozambique, segment. The Tonian orthogneiss sample is typical of (but somewhat younger than) the Marrupa Complex of NE Mozambique. No zircon inheritance was recorded in the sample, typical of the juvenile Marrupa Complex. On the other hand, the ca. 650 Ma granite pluton has an age that is typical of the northern segment of the orogen; this is the first recorded granite of that age intruded into the Tonian-dominated crust of southern Tanzania or NE Mozambique. The two younger granites have provided dates that are typical of the southern segment of the orogen, and that of the Kuunga Orogen. The study area thus appears to represent an area of transitional crust straddling two complex and contrasting segments of the East African Orogen, with elements of both segments present and evidence for a ca. 770 Ma event which appears to be quite widespread and may relate to the early phases of Gondwana amalgamation in southern East Africa.

Thomas, Robert J.; Bushi, Alphonce M.; Roberts, Nick M. W.; Jacobs, Joachim

2014-12-01

64

Calibrating the Younger Dryas  

Science.gov (United States)

Calibrating the Younger Dryas Contributed by: Thom Davis, Greg Wiles, Roger Brown, David Bary This activity was developed during the Teaching Climate Change from the Geological Record workshop, held in August ...

65

Feel Younger, Live Longer?  

Medline Plus

Full Text Available ... deaths from all causes. The results? People whose self-perceived age was younger than their real age ... felt their age or older. The relationship between self-perceived age and cardiovascular death was strong, but ...

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Petrography and geochemistry of the topaz-bearing granite stocks in Artjärvi and Sääskjärvi, western margin of the Wiborg rapakivi granite batholith  

Directory of Open Access Journals (Sweden)

Full Text Available The Artjärvi and Sääskjärvi granite stocks at the western margin of the Wiborg rapakivi batholith are multiphase rapakivi granite intrusions in which the most evolved phase is topaz-bearing granite. The Artjärvi stock is composed of porphyritic and even-grained biotite granite and even-grained topaz granite, and the Sääskjärvi stock comprises even-grained biotite granite and porphyritic topazgranite. The granites are metaluminous to peraluminous A-type granites, showing within-plate (WPG geochemical characteristics. The topaz granites from the Artjärvi and Sääskjärvi stocks are petrographically and geochemically similar to other topaz-bearing rapakivi granites in Finland. The anomalous geochemistry of the topaz granite is essentially magmatic; postmagmatic reactions have only slightly modified its composition. Greisen veins, some of which are mineralized, are widely found associated with the Artjärvi and Sääskjärvi stocks.The most characteristic feature of the Artjärvi granite stock is a stockscheider at the roof contact of the topaz granite. The stockscheider is composed of schlieren layering and pegmatite layers parallel to the contact. The most probable mechanism for the formation of the schlieren layering is velocity-gradient sorting parallel to the flow, which led to accumulation of mafic minerals along the upper contact of the topaz granite. Cooling and contraction of the topaz granite formed fractures parallel to the roof contact and the residual pegmatite magmas were injected along the fractures forming pegmatite layers. Textures like graphic intergrowths, aplitic groundmass and fan-shaped alkali feldspar crystals associated with the Artjärvi porphyritic biotite granite and pegmatite indicatecrystallization from undercooled magma. Miarolitic cavities found in the porphyritic biotite granite and topaz granite indicate at least local volatile saturation.

Sari Lukkari

2002-01-01

67

Ages of granites of the Serrinha Nucleus, Bahia (Brazil): an overview  

International Nuclear Information System (INIS)

The ages of granites of the Serrinha Nucleus (SN), in the eastern part of Bahia State, Brazil are poorly constrained and radiometric dating is mainly by the Rb-Sr whole rock isochron method, indicating a complex intrusive history. New Pb-Pb and U-Pb zircon for plutons widely distributed within the SN terrains range from Archean (>3070 Ma) to Paleoproterozoic (2067 Ma) and generally support the interpretation that at least three plutonic events affect these terrains. The range of ages evidently constitutes a large interval of regional granitic emplacement which can be divided into three principal domains: pre, syn and late/post tectonic. The new Archean ages (2.7 to 3.1 Ga.) by the U-Pb zircon method indicate reworking of an older crust during the Paleoproterozoic plutonic event in the SN region and clearly point to the existence of an Archean basement prior to 2.7 Ga. (Jequie Cycle). The younger ages help to further constrain the extension and age of Archean components of the Sao Francisco Craton which is important for a complete understanding of the Precambrian geology of that part of Brazil. (author)

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Geochemistry and geochronology of Paleozoic intrusions in the Nalati (Narati) area in western Tianshan, Xinjiang, China: Implications for Paleozoic tectonic evolution  

Science.gov (United States)

The Nalati (Narati) area in the Chinese western Tianshan is characterized by abundant Paleozoic intrusions, including granites, diorites and gabbros. They are not only indicators of the interaction between crust and mantle, but also useful clues for tracing the tectonic history of the Tianshan Orogen. Most Early Paleozoic granitoids (biotite monzonitic granites and muscovite granites) of this study are from the Yili Block. The biotite monzonitic granites (mixed-source-derived I-type granites) have a zircon U-Pb age of 497.0 ± 5.9 Ma, indicating the time of the subduction of the Terskey Oceanic crust in the Late Cambrian. The 427.2 ± 5.7 Ma Zircon U-Pb age of the S-type muscovite granites let us interpret that these granites may have been formed during the crust thickening process after the collision between the Yili Block and the Nalati Block. In western Tianshan the Late Paleozoic biotite granites, muscovite granites, quartz diorites, biotite monzonitic granites, granodiorites and alkali granites have respectively a LA-ICPMS zircon U-Pb age of 371.8 ± 6 Ma, 357.2 ± 7.5 Ma, 313.9 ± 2.5 Ma and 296.9 ± 2.4 Ma. The biotite granites display I-type geochemical features and are considered to have been derived from a lower continental crust source. The muscovite granites have a pronounced S-type affinity and are considered to have been formed by the partial melting of thickened continental crust after the collision between the Central Tianshan Belt and the South Tianshan Belt. The quartz-diorites are adakite-like and have an I-type affinity, which are considered to have been formed by partial melting of a delaminated lower crust in a post-orogenic extension setting. The granodiorites also show some typical geochemical features of adakite. Their formation is considered to be related to the lower crustal delamination and the ascending of asthenosphere after the collision event. The alkali granites show an A-type granite affinity. They may have been formed in a within-plate tectonic setting and possibly related to rifting as a consequence of extension. The gabbros can be divided into two groups based on their geochemical characteristics and ages. The older gabbros (415-429 Ma) with lower TiO2 contents are formed in an arc-related setting. The younger ones (340-318 Ma) with higher TiO2 content are formed in an intracontinental setting and influenced by crustal contamination. Magmatic activities recorded by Paleozoic intrusions can constrain the tectonic history of the Tianshan region from subduction of oceanic crust to intraplate extensional collapse and to rifting, and can also corroborate that the final closure of the South Tianshan Ocean occurred in the Late Devonian-Early Carboniferous time.

Xu, Xue-Yi; Wang, Hong-Liang; Li, Ping; Chen, Jun-Lu; Ma, Zhong-Ping; Zhu, Tao; Wang, Ning; Dong, Yun-Peng

2013-08-01

69

The Layos Granite, Hercynian Complex of Toledo (Spain): an example of parautochthonous restite-rich granite in a granulitic area  

OpenAIRE

The Layos Granite forms elongated massifs within the Toledo Complex of central Spain. It is late-tectonic with respect to the F2 regional phase and simultaneous with the metamorphic peak of the region, which reached a maximum temperature of 800-850°C and pressures of 400-600 MPa. Field studies indicate that this intrusion belongs to the "regional migmatite terrane granite" type. This granite is typically interJayered with sill-like veins and elongated bodies of cordierite/ gar...

Barbero Gonza?lez, Luis C.; Villaseca Gonza?lez, Carlos

1992-01-01

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U-Pb zircon ages of members of the Salem Granatic Suite along the northern edge of the Central Damaran Granite Belt  

International Nuclear Information System (INIS)

Porphyric Salem Suite granite rocks in the low-grade Northern Zone and adjoining portion of the high-grade Central Zone give respective ages of 589+- 40 and 546+- 30 m.y. (2 omnicron) which are indistinguishable within the limit of uncertainty. A complex, diachronous tectonic history is evident. Ages of deformation and granite intrusion in the Northern Zone and the coastal region of the Huab and Ugab Rivers appear to be similar. Deposition of the Mulden Group, the single intense phase of deformation and the low-grade metamorphism of the Northern Zone were completed between 550 and 600 m.y. ago and prior to the first granite intrusions. This was between 54 and 140 m.y. before completion of deformation in the adjoining, fundamentally different, high-grade, tectonically complex, granite-rich Central Zone. D1 in the southern Central Zone is older than 595 m.y. D2 may have been coeval in both the Northern and Central Zones, but a northward decrease in age across the Central Zone cannot be ruled out. D3 decreases in age northwards across the Central Zone and is at least 20 m.y. and may be as much as 120 m.y. younger in the north. The peak of metamorphism could have been coeval in the Northern and Central Zones. D3 in the northern Central Zone (479+- 16 m.y.) is the youngest major deformation event in the orogen. The Central Zone was finally thrust against and over the Northern Zone subsequent to D3 in the formerent to D3 in the former

71

The Younger Dryas Event  

Science.gov (United States)

This topic in depth deals with the Younger Dryas event, a short period of extremely cold temperatures interrupting the current interglacial period. It is currently debated whether the Younger Dryas event occurred solely in parts of the North hemisphere or throughout the world.The first website, (1), created by World History, provides a short, concise summary of the Younger Dryas period. Users can find a brief statement about the prevailing theory of the cause of this event. Lund University offers an amazing image of a stratigraphic record illustrating the Late Glacial sequence at the second website (2). Users can view the impressive Younger Dryas sedimentation layer and also see an image of the flower, _Dryas octopetala_, which the event is named after. Next, the Department of Natural Resources for the Province of Nova Scotia supplies images of the geologic landscape of Nova Scotia (3). Students can find descriptions of the Younger Dryas event and other glacial features. The forth website (4 ), produced by Klaus Keller as part of his lecture materials for classes at Penn State, is an online document illustrating the abrupt changes experienced on earth during the Younger Dryas. This website discusses the theorized relationship between the North Atlantic thermohaline circulation (THC) and the event. Next, the University of Arizona discusses its research on the environmental changes in mid-North America over the last several millennia (5). Users can learn how the researchers are attempting to create the first high-resolution chronology of the transition from the Late Glacial to the Early Holocene. In the sixth website (6 ), the University of Chicago offers an online article addressing the unknowns in our current understanding of climate change. Users can learn how the abrupt climate changes in the past such as the Younger Dryas are still difficult to model. Next, David J. Graham from the University of Wales addresses the importance of examining the moraine morphology and sedimentology in order to gather more knowledge about the climatic and glacio-dynamic conditions that occurred during the Younger Dryas period (7 ). This online poster provides images, figures, and descriptions of the interpretations of the landform-sediment associations present in the upper Ennerdale. Konrad Hughen from the Woods Hole Oceanographic Institution summarizes his group's research which illustrates the effects the northern tropical regions of the Southern Hemisphere experienced during the Younger Dryas event (8). In this downloadable document, users can learn about his group's creation of high-resolution records of tropical vegetation change that demonstrate the synchronization between the climate changes in the high latitude North Atlantic region and in the tropical South America during the event. Lastly, the U.S. Global Change Research Program discusses the classification of an abrupt climate change, the rapidity of past climate change according to the paleoclimatic records, the causes of climate change, and its consequences (9). Visitors can learn about the swiftness of the Younger Dryas event and how another occurrence like this may affect our society and the natural world.

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Gamma-spectrometric Surveys in Differentiated Granites. II: the Joaquim Murtinho Granite in the Cunhaporanga Granitic Complex, Paraná, SE Brazil  

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Full Text Available Detailed mapping at the NW corner of the large Neoproterozoic Cunhaporanga Granitic Complex (CGC, Paraná state, SE Brazil, redefined the Joaquim Murtinho Granite (JMG, a late intrusion in CGC with an exposed area of about 10 km2, made up mainly by evolved“alaskites” (alkali-feldspar leucogranites. This unit is in tectonic contact with the Neoproterozoic- Eocambrian volcano-sedimentaryCastro Group, to the W, and is intrusive into other less evolved granitic units of the CGC to the E. Petrographically, JMG shows mainlymesoperthite and quartz, with subordinate amounts of altered micas and some accessory phases, mainly zircon. The equi to inequigranulargranites are usually deformed with cataclastic textures, are often brecciated, and may have miarolitic structures. Formation of latealbite, sericite, carbonate and hematite was caused by deuteric and hydrothermal alteration. A gamma-ray spectrometric survey at 231stations which measured total counts (TC, Ueq K%, eU ppm and eTh ppm was used to construct several direct and derived maps. Comparedto neighboring units the JMG has signifi cant anomalies, especially in the TC, %K, eTh and eU maps, although the differences areless obvious in some derived maps. These evolved granites are enriched in these three elements. Geochemical behavior of K, Th and Uis used to analyse the results observed in maps. Enhanced weathering under a subtropical climate with moderate to high average temperaturesand heavy rainfall affects mainly feldspars and biotite, and may also destabilize most U and Th-bearing accessory phases. Th is most likely retained in restite minerals in soils, being relatively immobile, while part of U may migrate as uranyl ion in oxidizing media. K is especially affected by feldspar alteration to K-free clays (mainly kaolinite, and may be completely leached. Gamma-ray spectrometricmethods are valid tools to study facies in granitic rocks, especially in those that are enriched in K, Th and U.

Victor Miguel Oliveira Martin

2009-01-01

73

2005 dossier: granite  

International Nuclear Information System (INIS)

This document makes a status of the researches carried out by the French national agency of radioactive wastes (ANDRA) about the geologic disposal of high-level and long-lived radioactive wastes in granite formations. Content: 1 - advantage of granitic formations for the geologic disposal; 2 - containers; 3 - design study of a disposal facility in granitic environment; 4 - understanding and modelling of granite; 5 - description of disposal concepts in granitic environment; 6 - long-term and safety aspects; 7 - conclusion. (J.S.)

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Geochemistry and Geochronology U-Pb SHRIMP of granites from Peixoto de Azevedo: Alta Floresta Gold Province  

International Nuclear Information System (INIS)

The analysis of petrographic, geochemical and geochronological data of granites in the Peixoto de Azevedo region, Mato Grosso, Brazil, in the eastern portion of the Alta Floresta Gold Province, led to the recognition of two granitic bodies bounded by regional major faults and shear zones. In the northwestern portion a body with featured as biotite granodiorite, coarse-grained, with porphyritic to inequigranular texture, metaluminous to peraluminous, high-K calc-alkaline and magnesium character. In the southeastern portion of the area, a biotite monzogranite coarse-grained, with equigranular to porphyritic texture, slightly peraluminous, high-K calc-alkaline and dominantly of ferrous character. U- Pb dating (SHRIMP) showed that the biotite monzogranite has an age of 1869 ± 10 Ma, similar to the Matupa Intrusive Suite, while the biotite granodiorite has an age of 1781 ± 10 Ma, that is the age expected to Peixoto Granite. Both units show patterns of rare earth elements with enrichment of light over heavy and negative Eu anomaly (LaN/YbN » 7.6 to 17.31 and ratios Eu/EU? between 0.46 – 0.72 for biotite monzogranite and LaN/YbN » 7.13 to 29.09 with ratios Eu/Eu? between 0.25 - 0.40 for the biotite granodiorite). Trace elements pattern for both present negative anomalies of Ba, P, Ti and Nb indicating an evolution from mineral fractionation and subduction related sources. In this paper, it is suggested that the monzogranite Matupa was developed in mature arc tectonic environment. For the Peixoto Granite, two hypotheses are suggested: (a) it was developed in younger magmatic arc environment associated with the Colider Magmatism or (b) it was generated in extensional tectonic environment during the Columbia Super continent break up. (author)

75

Thorite in an Apollo 12 granite fragment and age determination using the electron microprobe  

Science.gov (United States)

We present the first quantitative compositional analysis of thorite in a lunar sample. The sample, a granitic assemblage, also contains monazite and yttrobetafite grains, all with concentrations of U, Th, and Pb sufficiently high to determine reliably with the electron microprobe. The assemblage represents the first documented occurrence of these three minerals together and only the second reported occurrence of thorite in a lunar rock. Sample 12023,147-10 is a small, monomict rock fragment recovered from an Apollo 12 regolith sample. It comprises graphic intergrowths of K-feldspar and quartz, and plagioclase and quartz, along with minor or accessory hedenbergite, fayalite, ilmenite, zircon, yttrobetafite, thorite, monazite, and Fe metal. Thorite, ideally ThSiO4, occurs in the assemblage adjacent to quartz and plagioclase, and includes a 12% xenotime ([Y,HREE]PO4) component. From quantitative electron-probe microanalysis (EPMA) of Th, U, and Pb in thorite, assuming that all of the measured Pb is radiogenic, we calculate an age of 3.87 ± 0.03 Ga. Yttrobetafite and monazite, which contain lesser concentrations of U, Th, and Pb than the thorite, yield ages of 3.78 ± 0.06 Ga and 3.9 ± 0.3 Ga, respectively. These dates are consistent with formation of the granitic material around 3.8-3.9 Ga, possibly associated with, or after, the formation of the Imbrium basin. This age falls within a group of younger ages for granitic samples, measured mainly by ion microprobe analysis of zircon, compared to a suite of older ages, ca. 4.20-4.32 Ga, also from zircons (Meyer et al., 1996). A 3.8-3.9 Ga age may reflect an origin following the Imbrium event whereby granitic melt formed as a result of heating and melting, and was mobilized and emplaced along an Imbrium-related ring-fracture system. Silicic volcanic or exposed intrusive materials occur in several circum-Imbrium locations such as the Mairan and Gruithuisen Domes and in ejecta excavated by Aristarchus crater. Perhaps sample 12023,147-10 and some of the other granitic materials sampled at the Apollo 12 site represent rocks similar to the rocks that make up these large silicic rock occurrences.

Seddio, Stephen M.; Jolliff, Bradley L.; Korotev, Randy L.; Carpenter, Paul K.

2014-06-01

76

Gamma-spectrometric surveys in differentiated granites. II: the Joaquim Murtinho Granite in the Cunhaporanga Granitic Complex, Parana, SE Brazil  

International Nuclear Information System (INIS)

Detailed mapping at the NW corner of the large Neo proterozoic Cunhaporanga Granitic Complex (CGC), Parana state, SE Brazil, redefined the Joaquim Murtinho Granite (JMG), a late intrusion in CGC with an exposed area of about 10 km2, made up mainly by evolved 'alaskites' (alkali-feldspar leuco granites). This unit is in tectonic contact with the Neoproterozoic-Eocambrian volcano-sedimentary Castro Group, to the W, and is intrusive into other less evolved granitic units of the CGC to the E. Petrographically, JMG shows mainly mesoperthite and quartz, with subordinate amounts of altered micas and some accessory phases, mainly zircon. The equi to inequigranular granites are usually deformed with cataclastic textures, are often brecciated, and may have miarolitic structures. Formation of late albite, sericite, carbonate and hematite was caused by deuteric and hydrothermal alteration. A gamma-ray spectrometric survey at 231 stations which measured total counts (TC), Ueq K%, eU ppm and eTh ppm was used to construct several direct and derived maps. Compared to neighboring units the JMG has significant anomalies, especially in the TC, %K, eTh and eU maps, although the differences are less obvious in some derived maps. These evolved granites are enriched in these three elements. Geochemical behavior of K, Th and U is used to analyse the results observed in maps. Enhanced weathering under a subtropical climate with moderate to high average temperatures and heavy rainfahigh average temperatures and heavy rainfall affects mainly feldspars and biotite, and may also destabilize most U and Th-bearing accessory phases. Th is most likely retained in restite minerals in soils, being relatively immobile, while part of U may migrate as uranyl ion in oxidizing media. K is especially affected by feldspar alteration to K-free clays (mainly kaolinite), and may be completely leached. Gamma-ray spectrometric methods are valid tools to study facies in granitic rocks, especially in those that are enriched in K, Th and U. (author)

77

Proterozoic granitic magmatism in the Fennoscandian Shield  

Science.gov (United States)

The main tectonic units of the Fennoscandian Shield are 1) the Archean 3.1--2.6 Ga granite gneiss (GGT) -- greenstone belt domain in the east, 2) the broad orogenic Svecofennian domain (1.9--1.8 Ga), and 3) the Southwest Scandinavian domain that consists of granitic gneisses, Gothian arc-type volcanic -- sedimentary and plutonic rocks (1.7--1.55 Ga), and has a Sveconorwegian (Grenvillian) overprint. The Svecofennian domain was formed by sequential accretion of volcanic arcs to the Archean craton (Lahtinen, 1994; Nironen, 1997). Rifting of the Archean craton at 2.50--2.44 Ga led to emplacement of a bimodal suite of layered mafic intrusions and minor A-type quartz syenites -- granites into the Archean crust in nortern Finland and adjacent Russia. Nd isotopes suggest Archean crustal source for some of the silicic plutons (Lauri and Mänttäri, 2003). The earliest Svecofennian granitoid rocks are ˜1.92 Ga gneissic calc-alkalic tonalities and granodiorites in central and northernmost Finland close to the Archean craton. I-type 1.89--1.87 Ga calc-alkalic granitoids of tonalite-granodiorite-granite association are common in the Svecofennian belts. In the Central Finland Granitoid Complex two suites can be separated: the 1.89--1.88 Ga calc-alkalic deformed granodiorites and granites, and the massive 1.88--1.87 Ga alkali-calcic or alkalic quartz monzonites and monzogranites (Nironen et al., 2000; Rämö et al., 2001). Southern Finland is characterized by 1.84--1.80 Ga migmatite-forming peraluminous S-type granites that were formed by anatectic melting of mainly sedimentary -- volcanic rocks of the thick Svecofennian crust. The Svecofennian plutonism was finished by intrusion of extension-related postorogenic (post-collisional) 1.80--1.77 Ga granite stocks that have a shoshonitic affinity and were possibly derived from enriched lithospheric mantle. Nd isotopes of the 1.81--1.77 Ga granites of northern Finland and the 1.88--1.86 Ga granites of eastern Finland near the Archean border indicate a major Archean source component (Huhma, 1986). The western margin of the Svecofennian domain is marked by the Transcandinavian Igneous Belt consisting of various 1.8--1.5 Ga granites. A-type rapakivi granites and associated diabase dikes of southern Finland, Russian Karelia, Baltic countries, and central Sweden can be divided into four age groups, from east to west: 1.56--1.53 Ga, 1.67--1.62 Ga, 1.59--1.54 Ga, 1.53--1.47 Ga. Bimodal magmatism, extensional setting and thinning of the lower crust below rapakivi granites can be explained by the mafic underplate model (Haapala and Rämö, 1992).

Haapala, I.; Lahtinen, R.; Rämö, O. T.

2003-04-01

78

Structural relationship between gebel qattar granite and the associated uraniferous hammamat sediments, north eastern desert, egypt  

International Nuclear Information System (INIS)

Gebel qattar granite is surrounded at its northern borders by the hammamat sediments of gebel U mm Tawat. The nature of the contact between these two different lithological rock units is thoroughly studied in the field. The contact zone is also subjected to an extensive geological, structural and radiometric studies. It is noteworthy to mention that the hammamat sediments at the contact are occasionally hosting uranium minerals with dark violet fluorite. The study revealed that gebel qattar granite forms a very large granitic intrusion which is forcefully intruded into the older rocks including hammamat sediments. The contact between this granite and its surrounding hammamat sediments is normal intrusive contact. The granites at some peripheral parts are occasionally episynitized and some times hosting uranium minerals. 40 figs, 1 tab

79

Earth's youngest exposed granite and its tectonic implications: the 10-0.8 Ma Kurobegawa Granite.  

Science.gov (United States)

Although the quest for Earth's oldest rock is of great importance, identifying the youngest exposed pluton on Earth is also of interest. A pluton is a body of intrusive igneous rock that crystallized from slowly cooling magma at depths of several kilometers beneath the surface of the Earth. Therefore, the youngest exposed pluton represents the most recent tectonic uplift and highest exhumation. The youngest exposed pluton reported to date is the Takidani Granodiorite (~ 1.4 Ma) in the Hida Mountain Range of central Japan. Using LA-ICP-MS and SHRIMP U-Pb zircon dating methods, this study demonstrates that the Kurobegawa Granite, also situated in the Hida Mountain Range, is as young as ~ 0.8 Ma. In addition, data indicate multiple intrusion episodes in this pluton since 10 Ma with a ~ 2-million-year period of quiescence; hence, a future intrusion event is likely within 1 million years. PMID:23419636

Ito, Hisatoshi; Yamada, Ryuji; Tamura, Akihiro; Arai, Shoji; Horie, Kenji; Hokada, Tomokazu

2013-01-01

80

Earth's youngest exposed granite and its tectonic implications: the 10–0.8 Ma Kurobegawa Granite  

Science.gov (United States)

Although the quest for Earth's oldest rock is of great importance, identifying the youngest exposed pluton on Earth is also of interest. A pluton is a body of intrusive igneous rock that crystallized from slowly cooling magma at depths of several kilometers beneath the surface of the Earth. Therefore, the youngest exposed pluton represents the most recent tectonic uplift and highest exhumation. The youngest exposed pluton reported to date is the Takidani Granodiorite (~ 1.4 Ma) in the Hida Mountain Range of central Japan. Using LA-ICP-MS and SHRIMP U-Pb zircon dating methods, this study demonstrates that the Kurobegawa Granite, also situated in the Hida Mountain Range, is as young as ~ 0.8 Ma. In addition, data indicate multiple intrusion episodes in this pluton since 10 Ma with a ~ 2-million-year period of quiescence; hence, a future intrusion event is likely within 1 million years. PMID:23419636

Ito, Hisatoshi; Yamada, Ryuji; Tamura, Akihiro; Arai, Shoji; Horie, Kenji; Hokada, Tomokazu

2013-01-01

81

Uranium rich granite and uranium productive granite in south China  

International Nuclear Information System (INIS)

The paper briefly introduces the differences between uranium rich granite and uranium productive granite in the 5 provinces of South China, and discusses their main characteristics in 4 aspects, the uranium productive granite is highly developed in fracture, very strong in alteration, often occurred as two-mica granite and regularly developed with intermediate-basic and acid dikes. The above characteristics distinguish the uranium productive granite from the uranium rich granite. (authors)

82

Metallogenic aspects of Itu intrusive suite  

International Nuclear Information System (INIS)

The integrated use of geological, geochemical, geophysical and remote sensing data is providing interesting new information on the metallogenic characteristics of the Itu Intrusive Suite. During World War II, up to 1959, a wolframite deposit was mined near the border of the northernmost body (Itupeva Granite). This deposit is formed by greisen veins associated with cassiterite and topaz, clearly linked with later phases of magmatic differentiation. Generally those veins are related to hydrothermal alteration of the granites and the above mentioned shear zone. U, Th and K determinations by field and laboratory gammaspectrometry were used for regional distribution analysis of those elements and its ratios and calculation of radioactivity heat production. In this aspects, the Itupeva Granite is the hottest and presents several anomalies in the Th/U ratio, indicative of late or post magmatic oxidation processes. (author)

83

Tectonic imprints within a granite exposed near Srinagar, Rajasthan, India  

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Partial melting in the middle to lower crustal level produces melts of granitic composition during orogeny. Thrusts play a vital role in their exhumation after consolidation of these granitic melts. In this paper we focus on one such granite along the eastern margin of the Delhi Fold Belt (DFB) rocks near Srinagar, Rajasthan, India. This is the first report of granite within the area and holds a key stratigraphic position in the entire rock package. The said granite is found to be intrusive to the DFB metasediments as well as their basement popularly known as the Banded Gneissic Complex (BGC). We disentangle the deformation fabrics seen within the granite and associated DFB metasediments, suggesting that subsequent to emplacement and consolidation, the granite has co-folded along with the country rocks. Three deformational events could be identified within the DFB metasediments namely, D1D, D2D and D3D. The peak metamorphism was achieved in the D1D event. The granite magma is generated and emplaced late syn-kinematic to D1D and thereafter is deformed by D2D and D3D producing D1G and D2G structural fabrics. These compressive deformations resulted in the collapse of the basin; the combined package of DFB rocks and the granite was thrusted eastwards over the basement rocks. The tectonic transport direction during thrusting is suggested eastwards from our structural analysis. Transverse faults developed perpendicular to the length of the granite have led to partitioning of the strain thereby showing a heterogeneity in the development of fabric within it.

Ruj, Trishit; Dasgupta, Nilanjan

2014-08-01

84

Petrology and geochemistry of the Los Cuartos granite, Tafi del Valle, Tucuman, northwest of Argentina: its integration to the regional magmatic layout  

International Nuclear Information System (INIS)

Los Cuartos Granite crops out on the western flank of the Cumbres Calchaquies, east of Tafi del Valle, Tucuman Province, Argentina. It has a granitic to granodioritic composition, of two micas, being biotite dominant. The granite is medium grained and inequigranular, with rare K-feldspar megacrysts. It contains host-rock xenoliths with different degrees of assimilation. The granite intrusion produced contact metamorphism in the surrounding basement, with development of andalucite porphyroblasts and poikiloblastic biotite. The granite is calk-alkaline and peraluminous, and is K- and P-rich and Ca- and Napoor compared to other granitoids of the region. The pluton shows late-tectonic features with regard to the regional deformation. The granite possibly intruded during the Ordovician (Famatinian Cycle) and its emplacement was structurally controlled by the Tafi Megafracture. Los Cuartos Granite and other intrusive bodies of the region share similar petrographical, geochemical, structural and geochronological characteristics. (Author).

85

Nuclide sorption on granite  

International Nuclear Information System (INIS)

Some equilibrium sorption experiments were made to evaluate surface and bulk reactions of granite. The nuclides examined are Cs and Np. The granite samples are sliced as thin as 0.7 to 1.3 mm and crushed samples (< 0.105 mm) are also used. The nuclide amount sorbed on granite of unit weight is dependent on the thickness of samples for both Cs and Np. The model that diffusion porosity decreases with the distance from the wall was proposed to explain these experimental results. Also, the error of measurements was examined. (author)

86

Petrochemical and Sr-Nd isotope investigations of Cretaceous intrusive rocks and their enclaves in the Togouchi-Yoshiwa district, northwest Hiroshima prefecture, SW Japan  

International Nuclear Information System (INIS)

Petrographic, petrochemical and Sr-Nd isotopic data are presented for granitoids and microdioritic enclaves from two Cretaceous stocks (Togouchi granodiorite and Tateiwayama granite porphyry) from the Togouchi-Yoshiwa district, northwest Hiroshima prefecture, SW Japan. The data are used to examine the genetic relationships between the microdioritic enclaves and their granitoid hosts. The granodiorite, granite porphyry and the microdioritic enclaves are all calc-alkaline in nature, and belong to the I-type ilmenite series. The Togouchi graniodiorite has a Rb-Sr whole rock isochron age of 85.6±4.7 Ma with an initial Sr isotope ratio (SrI) of 0.70634±0.00012 (2?). The Tateiwayama granite porphyry has a slightly younger Rb-Sr whole isochron age (77.4±3.1 Ma) but similar SrI of 0.70653±0.00015, suggesting that both stocks may have been derived from the same source. Despite diverse whole rock chemistry, the microdioritic enclaves in the respective intrusives have quite similar initial Sr and Nd isotope ratios, suggesting that they formed by fractional crystallization of a single magma, and also that the source of the enclaves in both intrusives had similar geochemical characteristics. In both stocks, however, the enclaves have distinctly lower initial Sr isotope ratios than their respective host rocks, indicating that they were derived from a different source than their hosts. In view of the geochemical and Sr-Nd isotope data, we infer that the enclave magmas were derifer that the enclave magmas were derived from a similar LILE- and LREE-enriched source to that of the Cretaceous basalts and gabbroic-dioritic rocks that are sporadically distributed in SW Japan. Such mafic to intermediate magmas were probably derived from the upper mantle, and transferred both heat and material to the lower crust, thus producing granitic magmas by partial melting. Successive mafic magmas or their differentiates could then have been injected into the granitic magma chamber, trapped and quenched, resulting in the formation of microdioritic enclaves in both granitic stocks. (author)

87

Petrogenesis of Triassic granites from the Nanling Range in South China: Implications for geochemical diversity in granites  

Science.gov (United States)

A combined study of whole-rock major-trace elements and Sr-Nd isotopes, zircon U-Pb ages, Hf and O isotopes as well as biotite geochemistry was carried out for Triassic granite intrusions from the Nanling Range in South China. The results provide insights into the effects of source composition and melting conditions on the geochemical diversity of granites. The granites of interest are peraluminous, and contain primary muscovite and tourmaline. They are characterized by high zircon ?18O values of > 9.0‰, high initial 87Sr/86Sr values of ~ 0.7200, and homogeneous ?Nd(t) values of - 11.3 to - 9.8, as well as variable zircon ?Hf(t) values of - 12.2 to - 5.8. Biotite geochemistry is similar to that of common peraluminous granites. An integrated interpretation of these petrological, mineralogical and geochemical data indicates that these granites were derived from partial melting of metasedimentary rocks under variable physicochemical conditions. The differences in whole-rock and biotite geochemistry between the intrusions are ascribed to the variable effects of source heterogeneity and melting temperature. The Luxi intrusion exhibits higher contents of MgO, FeOT, TiO2 and CaO than common melts derived from metasedimentary rocks, tight variations in major-trace elements and homogeneous Sr-Nd isotopic compositions, and homogeneous biotite composition with high Mg# [= Mg / (Mg + Fe) in molar] and lower whole-rock A/CNK values [= Al2O3 / (CaO + Na2O + K2O) in molar]. These can be explained by originating from a relatively mafic metasedimentary source. On the other hand, the geochemical diversity of granites can be caused by the difference in melting temperature in addition to the source heterogeneity. This is suggested by the Xiazhuang and Fucheng intrusions which exhibit similar range of SiO2. Nevertheless, the Fucheng intrusion is ferroan, and high in TiO2, (Na2O + K2O)/CaO, TiO2/MgO, Ga/Al and Zr + Nb + Ce + Y, but low in CaO, MgO and Mg#. Most of its major elements and their ratios are similar to those of A-type granites that were generated from F-rich rocks at high temperatures, consistent with the enrichment of Fe and F in its biotite. Thus, partial melting of a metasedimentary restite at reduced conditions after previous melt extraction is suggested to produce the geochemical feature of A-type granites in the Fucheng intrusion. In contrast, partial melting of fertile metasedimentary rocks would produce normal S-type granites like the Xiazhuang intrusion, with its geochemical variations ascrible to source heterogeneity and differential melting. Therefore, the geochemical composition of granites is primarily dictated by the composition of source rocks in addition to the physicochemical conditions of partial melting.

Gao, Peng; Zhao, Zi-Fu; Zheng, Yong-Fei

2014-12-01

88

Geochemical geochronology and genesis of granite from Coronel Murta, Northeast of Minas Gerais, Brazil  

International Nuclear Information System (INIS)

Geological, petrographic, geochemical (including rare-earth elements) and geochronological data of the Coronel Murta (Northeast Minas Gerais State) post-tectonic intrusive alkalic granites were summarized in order to discuss their genesis. This paper shows that Coronel Murta granites were generated by anatexis of dominantly metasedimentary rocks, in an ensialic environment, as the late results of an intraplate A-type subduction during the Brazilian Cycle. (author)

89

Petrography, Geochemistry and Geochronology of the Patrimônio Santo Antônio and São Domingos Granites (Cunhaporanga Granitic Suite, Paraná, Southeast Brazil  

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Full Text Available The Patrimônio Santo Antônio and São Domingos Granites are located in the northwest portion of the Itaiacoca Belt,which is part of the Apiaí Terrane (or tectonic domain, a segment of the southern Ribeira Belt, the major tectonic unit of theMantiqueira Province (Southeast Brazil. These granites are related to the Cunhaporanga Granitic Suite and are intrusive intometasedimentary rocks of the Itaiacoca Group. The plutons are represented mainly by porphyritic monzogranites, with rareoccurrences of syenogranites. The porphyritic monzogranites are ferroan to magnesian, high-K, alkali-calcic, and metaluminousto peraluminous. Trace elements patterns of the granites, which have been locally affected by hydrothermal alteration, suggestan association with magmas emplaced in a late- to post-tectonic setting. The geochemical signatures suggest a mantle sourceenriched in incompatible elements remobilized from the oceanic crust during subduction. The geochronological age of thePatrimônio Santo Antônio Granite (589 ± 6 Ma, zircon, U-Pb SHRIMP indicates that the magmatism associated with theseplutons occurred between the fi nal stages of evolution of the Cunhaporanga Granitic Suite (ca. 650 to 590 Ma and theemplacement of the post-orogenic and anorogenic plutons of the Apiaí Domain (ca. 590 to 570 Ma.

Sérgio Wilians de Oliveira Rodrigues

2011-12-01

90

Hydrogen isotope ratios of biotite and hornblende from some granitic masses in the Abukuma Plateau, Japan  

International Nuclear Information System (INIS)

D/H ratios and X sub(Fe)(Fe/(Fe + Mg)) values of coexisting biotite and hornblende from ''older'' and ''younger'' granitic rocks in the northern Abukuma Plateau were measured. These data show that both granitic rocks are the typical equilibrium type of Kuroda et al. (1978). However, delta D is higher and X sub(Fe) is lower for ''older'' granitic rocks than for ''younger'' granitic rocks. This difference may depend on the silica content of the whole rocks; e.g., that of ''older'' rocks is lower than that of ''younger'' ones. delta D value of ''aqueous fluid'' in the magma of these rocks can be estimated to be -3.0 -- -3.4%, which is the same to that for the Cretaceous granitic rocks in the Kitakami mountainous district. Hornblende in the gabbroic rocks associated with these granitic rocks was also investigated and it can be considered that the hornblendes were equilibrated with the water of ''aqueous fluid'' of the granitic magma. On the other hand, the biotite-hornblende pairs from the Samegawa, Ishikawa and Miyamoto masses do not show the simple equilibrium type but the disequilibrium or complicated type. This may be related to older ages (Paleozoic time) and poly-cyclic activities in terms of hydrogen isotope exchange equilibrium in these masses. (author)

91

Research on metallogenic specialization and metallogenic prognosis of granite in Nanling region: a case study of hydrothermal uranium deposit and hydrothermal tungsten-tin deposit  

International Nuclear Information System (INIS)

According to the principles of remote sensing information model and stepwise discriminant analysis, the metallogenic specialization discrimnant model of the intrusions rich in uranium and tungsten-tin was established, based on the data of 339 granite samples which consist of 99 granite samples rich in uranium, 89 granite samples rich in tungsten-tin and 151 granite under estimation in Nanling region. F test results showed that this model was applicable and highly significant for the intrusion estimation. The model was used to judge the uranium bearing or tungsten-tin bearing potential of the under estimated intrusions, and supplied a evidence for the further estimation of metallogenic intrusions. The built model has objectivity and operability, implements the quantitative evaluation for metallogenic specialization, and should play an important role on metallogenic specialization researches. (authors)

92

Granite gneiss basement on Flinders Island, South Australia  

International Nuclear Information System (INIS)

A U-Pb zircon age of 1762 ± 11 Ma is reported for granite gneiss located on Flinders Island, South Australia, This age is identical, within analytical uncertainty, to a previously reported age for schists of the Price Metasediments located 100 km to the southeast on the southwestern coast of the Eyre Peninsula. The outcrop represents the only known country rock to the Early Mesoproterozoic Calca Granite (Hiltaba Suite) of Flinders Island, the largest island of the Investigator Group of islands, in the southwestern Gawler Craton. The stratigraphic name Investigator Granite Gneiss is proposed for this rock unit. The discovery of the Investigator Granite Gneiss now considerably increases the extent of known Late Palaeoproterozoic rocks on the eastern side of the peninsula. The outcrop was previously included with the considerably younger St Peter Suite granite-monzogranite, and grouped together with other islands in the Investigator Group. This new dating suggests that the geology on the other islands may require revision. For the first time, detailed major and trace-element geochemistry is supplied for the granite gneiss on Flinders Island. Copyright (2004) Geological Society of Australia

93

Heater test 1, Climax Stock granite, Nevada  

International Nuclear Information System (INIS)

We conducted a series of in-situ tests in the Climax Stock, an intrusive granite formation at the Nevada Test Site, to validate the concept of housing a nuclear waste repository in granitic crystalline rock. The thermal properties of the granite were measured with resistance heaters and thermocouple frames that had been emplaced in drilled holes in the floor of a drift 420 m below the surface. Data analysis was performed primarily by comparing the measured and calculated temperature histories, varying conductivity and diffusivity in the calculations until reasonable agreement was achieved. The best-fit value for in-situ conductivity was approximately 3.1 W/m x K, and the deduced value for in-situ diffusivity was approximately 1.2 mm2/s. Anisotropic effects in the thermal field were less than 10%. Permeability was determined by sealing off portions of the drilled holes, using inflatable rubber packers and an air-pressurization system. We then compared the resulting decay in pressure with analytic solutions of the pressure loss from a cylindrical source in an infinite isotropic medium, obtaining a permeability of approximately 1 nanodarcy (nD) at about 300C. As the temperature increased, the permeability decreased to about 0.2 nD at about 500C and became too small to measure (<0.02 nD) at higher temperatures. These tests provided new data on the in-situ properties of a granite typical of the Basin and Range province and significantly advanced our understanding of and ability to perform in-situ thermal and permeability measurements. This knowledge will be of considerable value for future spent-fuel tests

94

Zircon fission-track dating of granites from the Vepor-Gemer Belt (Western Carpathians: constraints for the Early Alpine exhumation history  

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Full Text Available We present new zircon fission-track (ZFT data from Variscan granitoid bodies in the Veporic (footwall unit and Gemeric (hangingwall unit thick-skinned nappe sheets of the Central Western Carpathians. All samples show Late Cretaceous to earliest Paleogene cooling ZFT ages, which contribute to constraining the low-temperature exhumation history of the Vepor-Gemer Belt. Four granite samples from the western part of the Gemericum near the contact with the underlying Veporicum provided central ZFT ages between 70.4 ± 5.4 and 74.7 ± 5.6 Ma. One sample from this area shows an older age of 87.7 ± 5.9 Ma, possibly owing to its higher structural position. One remoter sample from the SE part of the Gemeric Unit has 61.7 ± 3.4 Ma central ZFT age, which probably reflects exhumation associated with a younger compressional tectonic event in that area. One sample from the centre of the Veporic metamorphic core complex yielded a cooling age 64.9 ± 4.8 Ma. However, most of these samples exhibit an internal age scatter pointing to complex cooling and exhumation history influenced by a slow passage through the zircon partial annealing zone and/or reheating brought about by the Cretaceous Rochovce granite intrusion. In spite of this, the acquired ages generally match the exhumation trend of the Veporic metamorphic core complex.

Plasienka D

2007-07-01

95

Metasomatism of ferroan granites in the northern Aravalli orogen, NW India: geochemical and isotopic constraints, and its metallogenic significance  

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The late Palaeoproterozoic (1.72-1.70 Ga) ferroan granites of the Khetri complex, northern Aravalli orogen, NW India, were extensively metasomatised ~900 Ma after their emplacement, at around 850-830 Ma by low-temperature (ca. 400 °C) meteoric fluids that attained metamorphic character after exchanging oxygen with the surrounding metamorphic rocks. Albitisation is the dominant metasomatic process that was accompanied by Mg and Ca metasomatism. A two-stage metasomatic model is applicable to all the altered ferroan intrusives. The stage I is represented by a metasomatic reaction interface that developed as a result of transformation of the original microcline-oligoclase (An12-14) granite to microcline-albite (An1-3) granite, and this stage is rarely preserved. In contrast, the stage II metasomatic reaction front, where the microcline-bearing albite granite has been transformed to microcline-free albite granite, is readily recognisable in the field and present in most of the intrusives. Some of them lack an obvious reaction interface due to the presence of stage II albite granites only. When studied in isolation, these intrusives were incorrectly classified and their tectonic setting was misinterpreted. Furthermore, our results show that the mafic mineralogy of metasomatised granites has a significant impact on the characterisation of such rocks in the magmatic classification and discrimination diagrams. Nevertheless, the stage I metasomatised granites can be appropriately characterised in these diagrams, whereas the characterisation of the stage II granites will lead to erroneous interpretations. The close spatial association of these high heat producing ferroan granites with iron oxide-copper-gold (IOCG), U and REE mineralisation in the region indicates a genetic link between the metasomatism and the mineralisation. World-class IOCG, U and REE deposits are associated with metasomatised ferroan granites, suggesting that such a relationship may act as a critical first-order exploration target for undiscovered mineral deposits.

Kaur, Parampreet; Chaudhri, Naveen; Hofmann, Albrecht W.; Raczek, Ingrid; Okrusch, Martin; Skora, Susanne; Koepke, Jürgen

2014-06-01

96

PETROGRAFÍA, GEOQUÍMICA Y GEOCRONOLOGÍA DEL GRANITO DE PARGUAZA EN COLOMBIA / PETROGRAPHY, GEOCHEMISTRY AND GEOCHRONOLOGY OF PARGUAZA GRANITE IN COLOMBIA  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish El Granito de Parguaza aflora en el departamento de Vichada-(Colombia), hacia la margen del río Orinoco y es parte del gran batolito descrito en Venezuela como Granito del Parguaza. Este cuerpo en Colombia aflora como cerros aislados tipo inselberg y serranías de poca extensión con pendientes abrupt [...] as que sobresalen entre las extensas llanuras terciarias. Representa uno de los granitos anorogénicos aflorantes más grandes del mundo y puede ser distinguido como una de las unidades colombianas más antiguas (Mesoproterozoico) que no han sufrido deformación. Se caracteriza por presentar textura rapakivi tipo wiborgita y piterlita, su composición es granítica a granítica de feldespato alcalino. Además de las variaciones composicionales y texturales, se encuentran zonas de grano fino, diques pegmatíticos, aplíticos y venas de cuarzo. Geoquímicamente se clasifica como un granito tipo A, metaluminoso a peralcalino, formado en ambiente post-colisional a anorogénico. Nuevas mediciones de U/Pb con LA-ICP-MS en circones indican nuevas edades concordantes de 1.392 ± 5 Ma y 1.402 ± 2 Ma para las partes más distales, respectivamente, mucho más jóvenes que edades propuestas anteriormente en territorio venezolano 1.545 Ma, lo cual puede ser interpretado como un intrusivo más complejo o como procesos de cristalización muy lentos de núcleo a borde. Por otro lado, estas edades son correlacionadas con granitos anorogénicos similares en el W del Cratón Amazónico en Brasil y con otros afloramientos rapakivi estudiados en el departamento de Guainía al SE de Colombia. Abstract in english The Parguaza Granite outcrops in the Vichada department of Colombia, towards the Orinoco River margin, where it conforms a portion of the large batholith described in Venezuela as Granito de El Parguaza. This intrusion outcrops in Colombia as isolated inselberg hills and moderately extended mountain [...] chains with abrupt slopes that protrude through Tertiary plains. It represents one of largest anorogenic granites worldwide and is one of the oldest colombian units (Mesoproterozoic) without tectonic deformation. The granite exhibits both typical Wiborgite and Pyterlite rapakivi texture, with a monzogranitic to alkali feldspar granitic composition. Among the compositional and textural variations, we find fine-grain zones, pegmatitic and aplitic dikes as well as quartz veins. Geochemically, it conforms a metaluminous to peralkaline A-type granite, intruded under post-collisional to rifting anorogenic conditions. New U/Pb measurements with LA-ICP-MS in zircons show hither to unknown concordant ages of 1392 ± 5 My to 1402 ± 2 My, respectively in the more distal zones; much younger than 1545 My ages reported in Venezuela, which may be explained or by a more complex intrusion and crystallization history or by a very slow crystallization process from the core to the edge; on the other hand, these ages are in concordance to similar anorogenic granites from the W Amazonian Craton in Brazil and with other rapakivi outcrops studied in the Guainía Department in the south-east of Colombia.

Amed, Bonilla-Pérez; José Carlos, Frantz; Juliana, Charão-Marques; Thomas, Cramer; José A., Franco-Victoria; Elise, Mulocher; Zeze, Amaya-Perea.

2013-12-01

97

Caracterización geoquímica del granito El Durazno, extremo norte de la sierra de Velasco, La Rioja / Geochemical characterization of El Durazno granite, Northern Sierrra de Velasco, La Rioja  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: Spanish Abstract in spanish El área de estudio se ubica en el norte de la sierra de Velasco, en la provincia de La Rioja. Está compuesta principalmente por rocas graníticas que cristalizaron durante dos eventos magmáticos principales en el Ordovícico y el Carbonífero. Los granitos más antiguos presentan diferentes grados de de [...] formación y los más jóvenes no están deformados. Los granitos datados como carboníferos hasta el presente en este sector son Asha y San Blas. Este último presenta una zona central más evolucionada químicamente, asociado a mineralizaciones de Sn. El granito El Durazno aflora al sureste del granito San Blas, no está deformado e intruye al ortogneis Antinaco, compuesto por rocas deformadas del Ordovícico. Es un granito postorogénico, peraluminoso y fuertemente diferenciado, con contenidos de Na2O>K2O. Presenta altos contenidos en Rb, Li, W, Cs, Nb y Ta y bajos en Ba, Sr, Y, Zr y Ce. El índice de caracterización geoquímica (GCI) para granitos asociados a mineralizaciones de W da valores positivos mayores que 4. Las tierras raras presentan contenidos totales bajos, entre 5,3 y 15,3 ppm, anomalía negativa de Eu y efecto tetrada convexo. En el borde norte del granito El Durazno existen vetas de cuarzo con wolframita y hematita distribuidas irregularmente que intruyen al ortogneis Antinaco. Tienen rumbo aproximado N-S y una corrida irregular. La ausencia de deformación, relaciones de campo y características geoquímicas indican que el granito El Durazno es un intrusivo muy diferenciado asociado a mineralización de W y de posible edad carbonífera. Abstract in english The studied area is located in the north of the sierra de Velasco, La Rioja province. It is mainly composed of granitic rocks that crystallized during two main magmatic events in the Ordovician and Carboniferous. The older granites have different types of deformation whereas the younger granites are [...] not deformed. Two Carboniferous granites have been dated in this area: Asha and San Blas. The latter has a chemically evolved central zone related to Sn mineralization. The El Durazno undeformed granite outcrops southeast of the San Blas granite, and intrudes into the deformed Ordovician Antinaco orthogneiss. It is a postorogenic, peraluminous and strongly differentiated granite, with contents of Na2O>K2O. It has high values of Rb, Li, W, Cs, Nb and Ta, and low values of Ba, Sr, Y, Zr and Ce. The geochemical characterization index (GCI) for W-bearing differentiated granites is positive with values greater than 4. The REE show low total contents, between 5,3 and 15,3 ppm, negative Eu anomalies and a convex tetrad effect. At the northern border of the El Durazno granite, quartz veins with irregularly distributed wolframite and hematite cross-cut the Antinaco orthogneiss. The veins have irregular north-south strike. The absence of deformation, field relations and geochemical characteristics indicate that the El Durazno granite is a highly differentiated intrusive associated with W mineralization and of possible Carboniferous age.

Miguel A, Báez; Ana S, Fogliata; Steffen, Hagemann; Fernando G, Sardi.

2012-12-01

98

Magnetic fabric and emplacement mechanisms in a co-mingled mafic and felsic magma chamber: the Espinharas granite (Borborema Province, NE Brasil)  

Science.gov (United States)

The Espinharas granite is a co-mingled mafic and felsic magmatic complex forming part of the widespread Brasiliano plutonism that affected the Borborema Province during the Neoproterozoic. Syenogranite is mixed and mingled with diorite generating a range of aluminous shoshonitic hybrid rocks containing mafic microgranular enclaves (MME) of various shapes and orientations. Geochemical modelling shows that the pluton originated by upper-mantle magma underplating and fault-assisted intrusion of diorite, which would supply heat for partial melting of the crust and formation of syenogranite. The Espinharas granite comprises syenogranites and diorites associated with quartz-monzonites, monzodiorites and syenites mainly deformed in the magmatic state. The pluton is emplaced within Paleoproterozoic augen gneisses from the basement and is bounded by high-temperature NE-trending mylonitic shear zones at its western and eastern borders. To the south, the pluton is in contact with the E-trending high-grade transpressional Patos shear zone. Magmatic foliations can be observed throughout the syenogranite and in the felsic rocks, being defined by a SPO of feldspars and quartz. However, they appear to be absent in the diorite. The microgranular enclaves display irregular contacts with the host syenogranite and may be often aligned in agreement with the magmatic foliation; they are also randomly dispersed and disrupted by monzo- to syenogranitic veins. The Anisotropy of Magnetic Susceptibility (AMS) technique was employed in order to investigate the mechanical relationships between mingled mafic and felsic magmas, as well as their emplacement mechanisms. Susceptibilities are usually high (k > 1.3 mSI), suggesting that Ti-magnetite is the main carrier of the magnetic signal. The magnetic lineation plunges shallowly to NE, parallel to the pluton main elongation axis. Zircons from diorite and syenogranite yield U-Pb (SHRIMP) ages of ~ 620 Ma, which are attributed to the crystallization of the granite and are younger than the main metamorphic event in the Seridó Belt (~ 575 Ma). These data suggest that the magnetic fabric of the Espinharas granite records the high-temperature deformation observed in the Seridó Belt. This deformation was active during a prolonged time range (~ 100 Ma) in a hybrid magmatic chamber emplaced in the middle- to shallow continental crust. These conditions indicate that the Patos shear zone controlled the development of the magmatic- to solid-state fabric of the Espinharas granite, highlighting the contribution of strain partitioning in the mechanical mingling of magmas in the continental crust.

Viegas, G.; Gouveia, F.; Archanjo, C.; Hollanda, M.

2013-12-01

99

Uranium distribution in the Um Samra-Um Bakra granitic plutons and associated pegmatites, Central Eastern Desert, Egypt  

International Nuclear Information System (INIS)

Um Samra -Um Bakra granitic plutons are located in the central Eastern Desert between latitudes 25 degree 15 and 25 degree 19 N and longitudes 34 degree 03 and 34 deg 11 E. The younger granites in the studied area are subdivided into two varieties, monzogranites and syenogranites. The syenogranites could be considered as uraniferous (fertile) granites, originated from highly fractionated, U-rich magma. They contain from 15.5 to 24.5 ppm uranium and from 20.5 to 25.0 ppm thorium. Both U and Th were essentially concentrated during the magmatic stage in accessory minerals as apatite, fluorite and zircon. The secondary processes as fracturing and alteration processes allowed the meteoric water and hydrothermal solutions to liberate labile uranium and redeposited their loads along micro fractures. Pegmatites show higher U-contents relative to both types of the studied younger granites. Pegmatites could be classified into two separate groups: 1) mineralized pegmatites which are located near the contact of Um Samra younger granites; they possess U-mineralization (kasolite) and 2) non-mineralized pegmatites which are distributed within Um Bakra younger granites themselves; they show lower U-contents relative to the first type. (author)

100

The rapakivi granite plutons of Bodom and Obbnäs, southern Finland: petrography and geochemistry  

Directory of Open Access Journals (Sweden)

Full Text Available The Obbnäs and Bodom granite plutons of southernmost Finland show the typical petrographic and geochemical features of the Proterozoic rapakivi granites in Finland and elsewhere: they cut sharply across the 1900 Ma Svecofennian metamorphic bedrock and have the geochemical characteristics of subalkaline A-type granites. The Bodom pluton is composed of porphyritic granites (hornblende-, hornblende-biotite-, and biotite-bearing varieties and an even-grained granite that probably represent two separate intrusive phases. This lithologic variation does not occur in the Obbnäs pluton, which is almost entirely composed of porphyritic hornblende-biotite granite that gradually becomes more mafic to the southwest. Three types of hybrid granitoids resulting from magma mingling and mixing occur on the southwestern tip of the Obbnäs peninsula. The Bodom granites are syenogranites, whereas the composition of the Obbnäs granite varies from syeno- to monzogranite. The main silicates of both the Bodom and Obbnäs granites are quartz, microcline, plagioclase (An1541, biotite (siderophyllite, and generally also amphibole (ferropargasite or hastingsite. Plagioclase-mantled alkali feldspar megacrysts are absent or rare. The accessory minerals are fluorite, allanite, zircon, apatite, and iron-titanium oxides; the Obbnäs granite also contains titanite. The Bodom and Obbnäs granites are metaluminous to weakly peraluminous, with average A/CNK of 1.00 and 1.05, respectively, have high Fe/Mg (average FeOtot/[FeOtot+MgO] is 0.94 for the Bodom and 0.87 for the Obbnäs granites, and high Ga/Al (3.78 to 5.22 in Bodom and 2.46 to 4.18 in Obbnäs. The REE contents are high with LREE-enriched chondrite-normalized patterns and moderate (Obbnäs to relatively strong (Bodom negative Eu-anomalies. The Obbnäs granite is enriched in CaO, TiO2, MgO, and FeO, and depleted in SiO2 and K2O compared to the Bodom granites. Also, there are differences in the Ba, Rb, and Sr contents of the two plutons (Ba and Sr higher, Rb lower in Obbnäs that cannot easily be traced to single parental granite magma. These features, together with the presence of titanite in the Obbnäs pluton, suggest different sources for the granites of the two plutons: a potassium feldspar-rich source for Bodom and potassium feldspar-poor for Obbnäs.

Kosunen, P.

1999-12-01

101

Study on Kalimantan uranium province: The assessment on uranium mineralization of metamorphic and granitic rocks at Schwaner mountains  

International Nuclear Information System (INIS)

Uranium exploration activities done by CEA-BATAN had discovered uranium occurrences as the radiometric and uranium content anomalies at metamorphic and granite rocks of Schwaner Mountains, Kalimantan. A part of the occurrences on metamorphic rocks at Kalan basin has been evaluated and be developed onto follow-up step of prospecting by construction of some drilling holes and an exploration adit. In order to increase the national uranium resources, it is necessarily to extent the exploration activity to out side or nearby of Kalan basin. The goal of this assessment is to understand the uranium accumulation mechanism at Pinoh metamorphic rocks of Kalan Kalimantan and to delineate areas that uranium may exist. The assessment was based on the aspect of geology, anomaly of radioactivity and uranium contents, tectonics and alterations. Pinoh metamorphic rocks which is influenced by Sukadana granite intrusion are the high potential rocks for the uranium accumulation, because the intrusion contains a relatively high of U, Th, Cu, Zn, Nb, Mn, and W. The potential rock distributions are in between G. Ransa granite intrusion at the east and Kotabaru granite intrusions at the west. The mineralizations are categorized as vein type deposits of granitic association

102

Isotopic age determinations in Bergslagen, Sweden. 3. The Hyttsjoe suite of gabbro-diorites and tonalite-granites, Filipstad area  

Energy Technology Data Exchange (ETDEWEB)

Rb-Sr whole-rock isotope analyses of five granite and two diorite samples of the Hyttsjoe Suite of intrusions in the Filipstad region, Central Sweden, yield an isochron age of 1841 +- 55 Ma with an initial /sup 87/Sr//sup 86/Sr ratio of 0.70217 +- 0.00098. This age is regarded as the emplacement age of the Hyttsjoe Suite of gabbros-diorites-tonalites-granites, which thus represents an intrusive subdivision of the 1.9-1.8 Ga Bergslagen Supracrustal Series.

Oen, I.S. (Amsterdam Univ. (Netherlands). Geologisch Inst.); Wiklander, U. (Sveriges Geologiska Undersoekning, Uppsala)

1982-09-01

103

Rb-Sr and K-Ar geochronology and petrogenesis of the Aji Granite in the eastern Sanuki district, Ryoke Belt, southwest Japan  

Energy Technology Data Exchange (ETDEWEB)

The Rb-Sr and K-Ar geochronological study was made for the Aji Granite in the eastern Sanuki district, one of the fine-grained granites in the Ryoke Belt. This granite is divided into hornblende-free and hornblende-bearing facies. The former gives a Rb-Sr whole-rock isochron age of 82.9{+-}8.0 Ma with SrI of 0.70773{+-}0.00007 which is interpreted as the intrusive age of the Aji Granite and therefore the final plutonism in the eastern Sanuki district. Biotites separated from six samples give K-Ar biotite ages between 80.4 Ma and 79.4 Ma. K-Ar hornblende age is of 83.5 Ma. These age data suggest rapid cooling after the emplacement of the granite. The initial Sr and Nd ratios of the Aji Granite fall within the range of the Ryoke granitoids. They are close to those of the Fine-grained in the Awaji Island, but differ from those of the Busetsu, Kadoshima and Otagiri Granites in the Chubu district. The Aji Granite and Fine-grained Granite in the Awaji Island have I-type granite chemical characteristics, whereas other fine-grained granites in the Ryoke Belt have S-type characteristics. This suggests varying source characteristics for the fine-grained granitic magmas in the Ryoke Belt. (author)

Yuhara, Masaki [Fukuoka Univ. (Japan). Dept. of Earth System Science, Faculty of Science; Miyazaki, Takashi [Kyoto Univ., Beppu (Japan). Inst. for Geothermal Sciences; Kagami, Hiroo [Niigata Univ. (Japan). Graduate School of Science and Technology; Yuhara, Mie

2003-02-01

104

Interior intrusion detection systems  

International Nuclear Information System (INIS)

The purpose of this NUREG is to present technical information that should be useful to NRC licensees in designing interior intrusion detection systems. Interior intrusion sensors are discussed according to their primary application: boundary-penetration detection, volumetric detection, and point protection. Information necessary for implementation of an effective interior intrusion detection system is presented, including principles of operation, performance characteristics and guidelines for design, procurement, installation, testing, and maintenance. A glossary of sensor data terms is included. 36 figs., 6 tabs

105

Network Intrusion Detection System  

OpenAIRE

Attacks on computers and data networks have become a regular and sophisticated issue. Intrusion detection has shifted its attention from hosts and operating systems to networks and has become a way to provide a sense of security to these networks. The aim of intrusion detection is to detect misuse and unauthorized use of the computer systems by internal and external elements. Typically, Intrusion Detection Systems allow statistical anomaly and rule-based misuse models to detec...

Gopalkrishna N. Prabhu,; Kushank Jain

2014-01-01

106

Intrusion Detection System: Overview  

OpenAIRE

Network Intrusion Detection (NID) is the process of identifying network activity that can lead to the compromise of a security policy. In this paper, we will look at four intrusion detection approaches, which include ANN or Artificial Neural Network, SOM, Fuzzy Logic and SVM. ANN is one of the oldest systems that have been used for Intrusion Detection System (IDS), which presents supervised learning methods. However, in this research, we also came across SOM or Self Organizi...

Alanazi, Hamdan O.; Noor, Rafidah Md; Zaidan, B. B.; Zaidan, A. A.

2010-01-01

107

Intrusion detection sensors  

International Nuclear Information System (INIS)

Intrusion detection sensors are an integral part of most physical security systems. Under the sponsorship of the U.S. Department of Energy, Office of Safeguards and Security, Sandia Laboratories has conducted a survey of available intrusion detection sensors and has tested a number of different sensors. An overview of these sensors is provided. This overview includes (1) the operating principles of each type of sensor, (2) unique sensor characteristics, (3) desired sensor improvements which must be considered in planning an intrusion detection system, and (4) the site characteristics which affect the performance of both exterior and interior sensors. Techniques which have been developed to evaluate various intrusion detection sensors are also discussed

108

Contribution to the uranium geochemistry on granites in Ecuador  

International Nuclear Information System (INIS)

This work aims to define the position of two of Ecuador granitic deposits within the field of the geochemistry of granites in general and of the geochemistry of uranium in particular. The regions concerned are: The Bonita and ABITAGUA. For each range the petrochemical framework is first of all determined and then the degree of chemical homogeneity of rocks is evaluated. In the petrochemical groups thus obtained the geochemical behaviour of the uranium is studied. From the viewpoint of the geochemistry of the granites under investigation, a comparison of the laws of distribution of the mayor elements in two ranges shows up a covergence of average composition which was not anticipated by geological and petrografic considerations alone. The statistical and geochemical distribution laws of the total uranium as a function of petrochemical variations are established. A study of chemical forms of uranium in the rocks has drawn an attention to the qualitative and quantitative importance of the faction of uranium soluble in delute acids. We have therefore reconsidered on the one hand, the laws of distribution of the insoluble and we have justified on the other hand the interest presented by the soluble post magmatic phenomena which makes possible to find a genetic connection between the uraniferous deposits and the intrusive massifs. Finally we have given tables of analytic composition total of the granites. (Author)

109

Radioelemental characterization of neoproterozoic south Khasi batholith and mylliem granite pluton by portable gamma-ray spectrometry: its implication on uranium exploration in parts of east and west Khasi hills, Meghalaya  

International Nuclear Information System (INIS)

Younger granite activity in the form of South Khasi Batholith (SKB), Kyrdem, Mylliem and Nongpoh plutons occur as intrusive into the basement gneissic complex and Paleo-Mesoproterozoic Shillong group of rocks. Ground portable gamma ray spectrometric survey carried out over the SKB, the Mylliem pluton and the basement gneissic complex. The eTh, eTh/eU and K contours clearly demarcate their lithocontacts. Radiometrically, these plutons are of hyperacidic to alkaline in nature. The magmatic evolution and the differentiated origin of granites are reflected by high concentration of eTh and K. The low Th/K values within the pluton indicate presence of diorite bodies and also suggest K enrichment along the margin of the Mylliem pluton. Higher concentration of radioelements along the margin of Mylliem pluton may be due to the role of hydrothermal phase to transport the radioelements. The high eTh/eU values and uranium favourability index of the SKB may imply possible loss of considerable amount of uranium to become provenance for the nearby uranium districts. (author)

110

Geological characteristics of granite type uranium deposits in middle of Inner Mongolia in comparison with south China  

International Nuclear Information System (INIS)

Granites extensively distributed in middle of Inner Mongolia and South China, namely Caledonian, Hercynian and Yanshanian. Some of the intrusive are composed of granites which belong to different ages. Some of the uranium deposits were found inside the granite bodies or in sedimentary rocks and meta sedimentary rocks along the exocontact zone. Granite rock was comparing in middle Inner Mongolia and South China, including Uranium ore-forming geological conditions. ore-forming process and Ore-controlling factors. Think the Uranium ore-forming geological conditions is similar; ore-forming process is mainly for low-mid temperature hot liquid; Uranium ore bodies (uranium mineralization) was controlled by fracture. Explain granite type uranium mineralization potential is tremendous in middle of Inner Mongolia. (author)

111

Yeguang granite and uranium metallogeny  

International Nuclear Information System (INIS)

The geological, petrologic and geochemical characteristics of rock body of yeguang granite are discussed with emphasis on clarification of occurrence of uranium in rock body and uranium deposit characteristics related to rock body, based on extensive field observations and laboratory test. View points are presented that granite refers to genetic series of terrestial crust transformation tye and uranium deposit is hot water deposit

112

Preliminary CHIME dating of granites from the Nkambe area, northwestern Cameroon, Africa  

International Nuclear Information System (INIS)

The chemical Th-U-total Pb isochron method (CHIME) has been adopted for dating the syntectonic foliated and post-tectonic unfoliated granites in northwestern Cameroon. The CHIME ages are 532±35 Ma for allanite and 523±45 Ma for zircon from Sample I10 of foliated biotite granite, 530±9 Ma for monazite from Sample N9 of foliated two-mica granite, and 510±25 Ma for monazite from Sample I4 of unfoliated two-mica granite. Several monazite grains from Samples N9 and I4 yield 436±13 and 420±16 Ma CHIME ages, respectively. The 532-510 Ma ages are interpreted as the time of granite emplacement and the 436-420 Ma ages as the time of hydrothermal alteration. The CHIME ages coupled with the concordant relation between the foliated granites and migmatitic gneiss suggest a ca. 530 Ma metamorphic-plutonic episode in northwestern Cameroon rather than a thermal overprint by granite intrusion. (author)

113

Origin, distribution and glaciological implications of Jurassic high heat production granites in the Weddell Sea rift, Antarctica  

Science.gov (United States)

The distribution of heat flow in Antarctic continental crust is critical to understanding ice sheet nucleation, growth and basal rheology and hydrology. We identify a group of High Heat Production granites intruded into Palaeozoic sedimentary sequences which may contribute to locally high heat flow beneath the central part of the West Antarctic Ice Sheet. Four of the granite plutons are exposed above ice sheet level at Pagano Nunatak, Pirrit Hills, Nash Hills and Whitmore Mountains. A new U-Pb zircon age from Pirrit Hills of 177.9 ± 2.3 Ma confirms earlier Rb-Sr dating that suggested an Early-Middle Jurassic age for the granites, coincident with the Karoo-Ferrar large igneous province and the first stage of Gondwana break-up. Our recently-acquired aerogeophysical data indicate that the plutons are distributed unevenly over 1000 km2 and were intruded into the actively extending, locally transcurrent, Jurassic Weddell Sea Rift [1]. In the NW part of the rift, the Pirrit Hills, Nash Hills and Whitmore Mountains granites form small isolated intrusions within weakly deformed upper crust. In the SE part of the rift, where granite intrusion was strongly structurally controlled within transtensional structures, the Pagano Nunatak granite is the only outcrop of a probably multiphase, ca 180 km long granite intrusion. The granites are weakly peraluminous, S-type and have Th and U abundances up to 61 and 19 ppm respectively. Heat production of analysed granite samples is ca. 2.9-9.1 µWm-3, toward the upper limit of values for High Heat Production granites globally. The granites are thought to have been generated during mafic underplating of the Weddell Rift during eruption of the contemporaneous Karoo-Ferrar magmatism [2]. The high Th and U abundances may be related to fractionation of the high Th-U Ferrar basaltic magmas combined with assimilation of pelitic sedimentary rocks. The granites correspond to an area of West Antarctica that may have heat flow significantly above the Antarctic average, as predicted from satellite magnetic data [3]. [1] Jordan, T.A., et al., Inland extent of the Weddell Sea Rift imaged by new aerogeophysical data, Tectonophysics (2012), 10.1016/j.tecto.2012.09.010 [2] Storey, B.C., et al., Middle Jurassic within-plate granites in West Antarctica and their bearing on the break-up of Gondwanaland. J. Geol. Soc. Lond, (1988), 145, 999-1007. [3] Fox Maule, C., et al., Heat flux anomalies in Antarctica revealed by satellite magnetic data. Science (2005), 10.1126/science.1106888

Leat, Phil T.; Jordan, Tom A. R. M.; Ferraccioli, Fausto; Flowerdew, Michael; R, Riley, Teal; Vaughan, Alan P. M.; Whitehouse, Martin

2013-04-01

114

Geochemistry of pegmatites associated with the Cape Coast granite complex of southern Ghana  

International Nuclear Information System (INIS)

The Cape Coast granite complex, which is associated with the metasedimentary basin rocks of Birimian in Ghana are, also referred to as the basin - type granitoids, and forms part of the two major types of Eburan granitoids in Ghana. The Cape Coast granite complex is characterized by various intrusions such as acid intrusion and pegmatites. The pegmatites associated with the Cape Coast granite complex are noted to be related to the margin of the granite batholiths. The mineralogical characteristics of the pegmatites have been documented, but there is little published information on the geochemical characteristics, source and tectonic settings and mode of emplacement of these pegmatites as compared to the Cape Coast granite complex. The objectives of this project were therefore to determine the compositions and geochemistry of the pegmatite and use the data to infer the possible source of these pegmatites. The geochemical data indicates that the pegmatites of the Egyaa, Saltpond and Akim Oda areas consist of a low to high-K, S-type characteristics, with three samples from Saltpond having metaluminous character. Lower values of molar CaO/ (MgO + FeOtot) coupled with higher values of molar Al2O3/ MgO + Fetot) suggest their derivation from partial melting from metabalistic source. The data suggests the rocks so have emplaced in a volcanic arc and ocean ridge geotectonic environment. (au)

115

New evidence of basement in the Svalbard Caledonides: Early Proterozoic zircon ages from Ny Friesland granites  

International Nuclear Information System (INIS)

In Ny Friesland, northeastern Spitsbergen, the younger sedimentary rocks of the Hecla Hoek Complex closely resemble strata of similar age (ca. 800 to 470 Ma) in East Greenland. The pass downwards, apparently concordantly, into metasedimentary rocks which increase in metamorphic grade with depth. In their lower parts the latter include a variety of granitic gneisses. Zircons from a granite and gneissic granite have been analysed by the U-Pb and 207Pb/206Pb single crystal methods and have yielded ages of appr. 1700 to 1800 Ma. One of these granites intrudes metasediments, indicating an Early Proterozoic age. These ages imply that significant segments of pre-Caledonian crystalline basement are incorporated in the base of the Caledonian pile in northeastern Spitsbergen. 63 refs., 5 figs., 3 tabs

116

Petrology and geochemistry of the Los Cuartos granite, Tafi del Valle, Tucuman, northwest of Argentina: its integration to the regional magmatic layout; Petrologia y geoquimica del granito Los Cuartos, Tafi del Valle, Tucuman, noroeste de Argentina: integracion al esquema magmatico regional  

Energy Technology Data Exchange (ETDEWEB)

Los Cuartos Granite crops out on the western flank of the Cumbres Calchaquies, east of Tafi del Valle, Tucuman Province, Argentina. It has a granitic to granodioritic composition, of two micas, being biotite dominant. The granite is medium grained and inequigranular, with rare K-feldspar megacrysts. It contains host-rock xenoliths with different degrees of assimilation. The granite intrusion produced contact metamorphism in the surrounding basement, with development of andalucite porphyroblasts and poikiloblastic biotite. The granite is calk-alkaline and peraluminous, and is K- and P-rich and Ca- and Napoor compared to other granitoids of the region. The pluton shows late-tectonic features with regard to the regional deformation. The granite possibly intruded during the Ordovician (Famatinian Cycle) and its emplacement was structurally controlled by the Tafi Megafracture. Los Cuartos Granite and other intrusive bodies of the region share similar petrographical, geochemical, structural and geochronological characteristics. (Author).

Lopez, J.P.; Bellos, L.I.

2010-07-01

117

Geology of the Northern part of the Strath Ossian Granite, Scotland  

International Nuclear Information System (INIS)

The Strath Ossian Granite is made up of granodiorite, dark, variable 'granodiorites' interpreted as mobilised diorite or basic material, appinite and porphyritic granodiorite. Huge rafts of psammitic metasediments occur within the mass and three fracture-zones and numerous dykes, dominantly of porphyrite, cut across it in a north-easterly direction. Granite emplacement may have occurred in stages, early batches being xenolith-rich and later ones xenolith-poor. New batches were intruded centrally, which created strong radial stresses, sufficiently strong to make room for the intrusion by forcing the metasedimentary country rocks downwards and aside. (author)

118

Microprobe monazite dating and the ages of some granitic and metamorphic rocks from southeastern Brazil  

Energy Technology Data Exchange (ETDEWEB)

Electron microprobe monazite crystallization ages are presented for selected granite and metamorphic rock samples from the Socorro and Guaxupe Nappes and the Alto Rio grande and Ribeira Belts, southeastern Brazil. Results are consistent with ages close to 625 Myr of the main metamorphic episode in the nappe structures. Anatetic granite magmatic events in these terranes and in the Alto Rio Grande Belt were roughly coeval, most samples sharing ages between 610-625 ({+-} 15) Myr. A crust-derived granite and a granite contact aureole from the Ribeira Belt have ages of 600-608 ({+-} 15) Myr., suggesting that the main granite magmatism in this belt was somewhat younger, probably contemporaneous with the late orogenic phase in the nappe domains. Some regional and granite samples from all these terranes point to possible inheritance or incompletely monazite grains and intra-grain domains giving older ages, up to 690 Myr. The microprobe age results agree very well with independent isotopic data, reinforcing the applicability of the method to highlight an overall picture of main geochronological trends within the continental crust. The high spatial resolution of the probe should play an important role in understanding geochronological patterns of metasedimentary rocks and related migmatites and granites, as these rocks and their minerals often present chemical and isotopic domains related to contrasting geological events, not always recognized by conventional dating schemes. (author)

Vlach, Silvio Roberto Farias; Gualda, Guilherme Augusto Rosa [Sao Paulo Univ., SP (Brazil). Inst. de Geociencias]. E-mail: srfvlach@usp.br

2000-03-01

119

Radioactivity studies of some granitic masses in south eastern Aswan, Egypt  

International Nuclear Information System (INIS)

Several granitic masses occur at Aswan area and in various localities in the south eastern desert; Abu-Aggag, El Hudi, and Um Akl localities. These granites belong either to the older grey granites or else to the younger or pink granites and were intruded into a country rock composed mainly of mica and hornblende schists. Field radiometric measurements of these granites gave results ranging from 80 cps to 165 cps. Chemical analysis has shown that uranium ranges from 4 to 32 ppm whereas thorium varies between nil and 32 ppm with Th/U ratios reaching up to 3.83. The field radiometric measurements are in complete coincidence with uranium and thorium analytical data. Investigation of the heavy minerals content separated from these granites revealed the presence of uranophane, uranothorite, beside monazite and zircon. In some localities, the zircon crystals are characterized by rounding of their corners and edges while some of them show overgrowths. This indicates that the corresponding granites are of migmatic origin

120

Microprobe monazite dating and the ages of some granitic and metamorphic rocks from southeastern Brazil  

International Nuclear Information System (INIS)

Electron microprobe monazite crystallization ages are presented for selected granite and metamorphic rock samples from the Socorro and Guaxupe Nappes and the Alto Rio grande and Ribeira Belts, southeastern Brazil. Results are consistent with ages close to 625 Myr of the main metamorphic episode in the nappe structures. Anatetic granite magmatic events in these terranes and in the Alto Rio Grande Belt were roughly coeval, most samples sharing ages between 610-625 (± 15) Myr. A crust-derived granite and a granite contact aureole from the Ribeira Belt have ages of 600-608 (± 15) Myr., suggesting that the main granite magmatism in this belt was somewhat younger, probably contemporaneous with the late orogenic phase in the nappe domains. Some regional and granite samples from all these terranes point to possible inheritance or incompletely monazite grains and intra-grain domains giving older ages, up to 690 Myr. The microprobe age results agree very well with independent isotopic data, reinforcing the applicability of the method to highlight an overall picture of main geochronological trends within the continental crust. The high spatial resolution of the probe should play an important role in understanding geochronological patterns of metasedimentary rocks and related migmatites and granites, as these rocks and their minerals often present chemical and isotopic domains related to contrasting geological events, not always recognized by conventional dating schemes. (authod by conventional dating schemes. (author)

121

Uranium enriched granites in Sweden  

International Nuclear Information System (INIS)

Granites with uranium contents higher than normal occur in a variety of geological settings in the Swedish Precambrian, and represent a variety of granite types and ages. They may have been generated by (1) the anatexis of continental crust (2) processes occurring at a much greater depth. They commonly show enrichement in F, Sn, W and/or Mo. Only in one case is an important uranium mineralization thought to be directly related to a uranium-enriched granite, while the majority of epigenetic uranium mineralizations with economic potential are related to hydrothermal processes in areas where the bedrock is regionally uranium-enhanced. (Authors)

122

Granites and granitoids of the southern region - Granite molybdenite system  

International Nuclear Information System (INIS)

Economic concentrations of molybdenum are genetically closely associated with acidic and moderately acid granitoids-granites, granodiorites, monzonites and diorites, and are located in two geotectonic settings: subduction-related and rift-related. The aim of this paper is twofold, first succinctly approach the geology, tectonic setting and chemical parameters of the 'granite molybdenite system' as defined by Mutschler and/or alcali granite porphyry bodies emplaced in the North American continent for occasion of a Mesozoic-Fanerozoic extensile event; second to relate the computer-assisted evaluation of 422 major element chemical analysis of granites and granitoids of southern region of Brazil, using chemical fingerprints (SiO2 ? 74. Owt%, Na2O ? 3.6wt%, K2O ? 4.5wt%), and K2O/Na2O ratio > 1.5 developed and testified from North American and Finnish occurrences, may locate molybdenite-bearing granite bodies with high exploration potential. These techniques suggest that some late Precambrian to early Paleozoic granite-rhyolite assemblages inserted at domains of the SG. 22/23 Curitiba/Iguape, SH. 21/22 Uruguaiana/Porto Alegre and SI.22 Lagoa Mirim Sheets, have exploration potential for molybdenum. (author)

123

Two Stages of Granite Formation in Accretional and Collisional Settings on the Example of Sredinny Range, Kamchatka, NE Russia  

Science.gov (United States)

New U-Pb SHRIMP zircon datings, analysis of tectonic setting and composition peculiarities of two granite complexes indicate that they mark stages of tectonic evolution of metamorphic complexes of Malka Rise of Sredinniy Range and are indicators of newly formed continental crust of Kamchatka. Granites are divided into gneissosed and equigranular types. Gneissosed granites intrude metamorphic formations of Kolpakovka Group. Equigranular granites intrude gneissosed granites, complexes of Kolpakovka and Kamchatka groups. U-Pb SHRIMP zircon datings of granites indicate two stages of granite formation: Campanian (~78-80 m.a.) and Early Eocene (52±2 m.a.). Petrography and petrochemical features of both types of granites make them similar to S-type granites. REE patterns allow distinguishing among equigranular and gneissosed granites two rock groups differ in their source and melting depth. The first stage of granite magmatism, formation of gneissosed granites (78-80 m.a.), is related to accretional setting at the Kamchatka margin of Eurasia. Granite magmatism in accretionary prism may be due to underplating of mafic material at the base of accretionary prism as a result of mantle wedge melting above subduction zone. The second stage of granite magmatism, formation of equigranular granites (52±2 m.a.), coincides in time with collision between Achayvayam-Valaginskaya ensimatic island arc and Kamchatka margin of Eurasia. After 55 m.y. ago during collision the quick thrusting of island arc slices over heterogeneous formations of the margin occurred. Intensive and quick transformations of the structure, including deep submergence, quick (3-5 m.a.) heating of the crust took place. It is resulted in metamorphism of high T and moderate P in the deep part of collisional zone and melting of granites. Quick heating of the crust, probably, was related to asthenosphere uprise as a result of Eurasian slab break-off, subducting beneath the arc. According to U-Pb SHRIMP zircon datings migmatization, partial melting and intrusion of equigranular granites occurred simultaneously. Work is supported by RFBR (N07-05-00255), FTsNTP leading scientific schools (NSh- 3172.2008.5).

Luchitskaya, M. V.; Soloviev, A. V.; Hourigan, J.

2008-12-01

124

Comparison of Proterozoic and Phanerozoic rift-related basaltic-granitic magmatism  

Science.gov (United States)

This paper compares the 1.67-1.47 Ga rapakivi granites of Finland and vicinity to the 1.70-1.68 Ga rapakivi granites of the Beijing area in China, the anorogenic ˜130 Ma granites of western Namibia, and the 20-15 Ma granites of the Colorado River extensional corridor in the Basin and Range Province of southern Nevada. In Finland and China, the tectonic setting was incipient, aborted rifting of Paleoproterozoic or Archean continental crust, in Namibia it was continental rifting and mantle plume activity that led to the opening of southern Atlantic at ˜130 Ma. The 20-15 Ma granites of southern Nevada were related to rifting that followed the Triassic-Paleogene subduction of the Farallon plate beneath the southwestern United States. In all cases, extension-related magmatism was bimodal and accompanied by swarms of diabase and rhyolite-quartz latite dikes. Rapakivi texture with plagioclase-mantled alkali feldspar megacrysts occurs in varying amounts in the granites, and the latest intrusive phases are commonly topaz-bearing granites or rhyolites that may host tin, tungsten, and beryllium mineralization. The granites are typically ferroan alkali-calcic metaluminous to slightly peraluminous rocks with A-type and within-plate geochemical and mineralogical characteristics. Isotope studies (Nd, Sr) suggest dominant crustal sources for the granites. The preferred genetic model is magmatic underplating involving dehydration melting of intermediate-felsic deep crust. Juvenile mafic magma was incorporated either via magma mingling and mixing, or by remelting of newly hybridized lower crust. In Namibia, partial melting of subcontinental lithospheric mantle was caused by the Tristan mantle plume, in the other cases the origin of the mantle magmatism is controversial. For the Fennoscandian suites, extensive long-time mantle upwelling associated with periodic, migrating melting of the subcontinental lithospheric mantle, governed by heat flow and deep crustal structures, is suggested.

Haapala, Ilmari; Rämö, O. Tapani; Frindt, Stephen

2005-03-01

125

Radioelement geochemistry of Irish granites  

International Nuclear Information System (INIS)

Data for U, Th, and K, determined by neutron activation analysis, in 128 rock samples from 14 Irish Caledonian and Tertiary granite plutons are summarized. Irish Newer Caledonian granites (ninety-four samples) have values of radioelements (average 3.6 ppm U, 12.1 ppm Th, and 3.4% K) consistent with derivation from a source of broadly uniform composition. U mineralization occurs in the voluminous and forcefully emplaced Main Donegal and Leinster plutons whereas smaller passively emplaced granites (Galway, Barnesmore, Rosses) lack mineralization. Irish Tertiary granites (thirty-four samples), which represent small batches of highly fractionated acid magmas, show moderate or high radioelement contents (11.5 ppm U, 39.9 ppm Th, 4.5% K) but are not mineralized. It is concluded that the use of elevated radioelement contents as a criterion of granite 'fertility' may be misleading in the British Isles Caledonian Province. The radioelement chemistry of granites may reflect their source composition more closely than expected for differentiated and/or contaminated acid melts. (author)

126

Geology, geochemistry, and geochronology of an A-type granite in the Mulock Glacier area, southern Victoria Land, Antarctica  

International Nuclear Information System (INIS)

On the north side of the Mulock Glacier and at Cape Teall in southern Victoria Land, Antarctica, deformed greenschist facies Skelton Group metasediments are intruded by the post-kinematic A-type Mulock Granite. Geochemical data indicate that this intrusive complex is similar to A-type granitoids previously described both to the north (Glee Intrusives and Penny Hill Granite), where they form part of the Koettlitz Glacier Alkaline Province, and to the south (Foggydog Granite Suite). A U-Pb zircon date of 546 ± 3 Ma on the Mulock Granite places a minimum constraint on the age, and timing of deformation of the Skelton Group rocks in this area, and indicates that the Mulock Granite was emplaced during the initial stages of the Ross Orogeny. This age also confirms that crystallisation of this granite body was synchronous with that of A-type granitoids from the Royal Society Range to Skelton Glacier area immediately to the north. (author). 60 refs., 7 figs., 2 tabs

127

The Torres del Paine intrusion as a model for a shallow magma chamber  

Science.gov (United States)

The shallow magmatic Torres del Paine Intrusive Complex (TPIC) belongs to a series of sub-volcanic and plutonic igneous bodies in Southern Chile and Argentina. This trench-parallel belt is located in a transitional position between the Patagonia Batholith in the West, and the alkaline Cenozoic plateau lavas in the East. While volumetrically small amounts of magmatism started around 28 my ago in the Torres del Paine area, and a second period occurred between 17-16 Ma, it peaked with the TPIC 12.59-12.43 Ma ago. The spectacular cliffs of the Torres del Paine National park provide a unique opportunity to study the evolution of a very shallow magma chamber and the interaction with its host rocks. Intrusion depth can be estimated based on contact metamorphic assemblages and granite solidus thermobarometry to 750±250 bars, corresponding to an intrusion depth of ca. 3km, ca. 500m above the base of the intrusion. Hornblende thermobarometry in mafic rocks agrees well with these estimates (Leuthold et al., 2014). The TPIC is composed of a granitic laccolith emplaced over 90ka (Michel et al., 2008) in 3 major, several 100m thick sheets, forming an overall thickness of nearly 2 km. Contacts are sharp between sheets, with the oldest sheet on the top and the youngest on the bottom (Michel et al., 2008). The granitic laccolith is under-plated by a ca. 400m thick mafic laccolith, built up over ca. 50ka (Leuthold et al. 2012), constructed from the bottom up. Granitic and mafic sheets are themselves composed of multiple metric to decametric pulses, mostly with ductile contacts between them, resulting in outcrop patterns resembling braided stream sediments. The contact of the TPIC with the Cretaceous flysch sediments document intrusion mechanism. Pre-existing sub-horizontal fold axes are rotated in the roof of the TPIC, clearly demonstrating ballooning of the roof; no ballooning was observed in the footwall of the intrusion. Extension during ballooning of the roof is indicated by dykes emanating from the roof of the intrusion into the host rocks. The dykes are perpendicular to the contact, radially shooting into the country rocks. Since the oldest granite is found in the roof, it is also permeated by dykes of successive intrusions. Contact metamorphism can be used to constrain the granite intrusion temperature to ca. 1000°C. Intrusion occurred in multiple pulses along the granite-host rock contact, in rapid succession, before significant cooling occurred in the aureole. Hydration of the biotite and feldspar of the immature sediments in the outer aureole contributed significantly to the overall thermal signature of the host-rock-TPIC system. In contrast, stable isotopes do not document significant fluid circulation. Leuthold, J., Müntener, O., Baumgartner, L., Putlitz, B., Ovtcharova, M., Schaltegger, U. (2012) Time resolved construction of a granitic to mafic laccolith (Torres del Paine, Patagonia). Earth Plan Sci Lett. 325. 85-92 Leuthold J., Müntener O., Baumgartner L.P., Putlitz B., (2014) Recycling of mafic crystal mush, transport and emplacement in the Torres del Paine mafic complex (Patagonia). J. Petrology; accepted pending revision Michel, J., Baumgartner, L.P. Putlitz, B., Ovtcharova, M., Schaltegger, U. (2008) Incremental growth of a shallow crustal laccolith over 80 kyrs: the Torres del Paine Granite, Patagonia. Geology vol. 36, 459-462

Baumgartner, Lukas; Bodner, Robert; Leuthold, Julien; Muntener, Othmar; Putlitz, Benita; Vennemann, Torsten

2014-05-01

128

Geothermal potential of Caledonian granites underlying Upper Palaeozoic sedimentary basins astride the Iapetus Suture Zone in Ireland  

Science.gov (United States)

Upper Palaeozoic sedimentary basins in Ireland overlie crystalline rocks within the Caledonian Iapetus Suture Zone. Beneath these basins, Lower Palaeozoic rocks, formed and deformed during the Caledonian orogenic cycle, were intruded by c. 420-390 Ma late-tectonic granites at various tectonic levels. These include the subsurface Kentstown and Glenamaddy granites discovered by mineral exploration drilling. While these granites comprise actual targets for Enhanced Geothermal System (EGS) exploration, several others likely exist based on geophysical considerations. In order to test the regional geothermal potential, the buried granites as well as analogue exposed rocks are being investigated geochemically. The geothermal potential of the intrusives depends on their heat production rate (HPR), which is calculated using rock density and concentrations of the heat producing elements (HPE) uranium, thorium and potassium. In spite of their close spacing and similar ages, the whole-rock geochemistry of the granites varies significantly, but with no obvious geographical control (Fritschle et al., 2013; 2014). The granite HPR values range from 1.4 ?W/m3 for the Dhoon Granite (Isle of Man) to 4.9 ?W/m3 for the Drogheda Granite (Ireland). This compares with the average HPR for a 'typical' granite of 2.7 ?W/m3 (Goldstein et al., 2009). It is demonstrated that an elevated HPR of a granite can be related to enrichment in one of the HPE alone (e.g., uranium-enrichment in the Foxdale Granite (Isle of Man), or thorium-enrichment in the Drogheda Granite). Enrichment in HPE in a granite may occur due to different reasons including hydrothermal (re-) distribution of uranium, or the assimilation of thorium-rich wall-rocks. Hence, the distribution of the HPE in particular minerals, veins and source lithologies, along with the petrophysical characteristics of the sedimentary basins and the granites' petrogenesis, are currently being investigated as possible mechanisms controlling their heat production budget. Fritschle, T., Daly, J.S., Whitehouse, M.J., McConnell, B., Buhre, S., 2013. U-Pb Zircon Ages from Granites in the Iapetus Suture Zone in Ireland and the Isle of Man. Mineralogical Magazine, 77(5): 1115. Fritschle, T., Daly, J.S., Whitehouse, M.J., McConnell, B., Buhre, S., 2014. Zircon geochronology and Hf-O isotope geochemistry from granites in the Iapetus Suture Zone in Ireland and the Isle of Man. This issue. Goldstein, B.A., Hill, A.J., Long, A., Budd, A.R., Ayling, B., Malavazos, M., 2009. Hot rocks down under - evolution of a new energy industry. Geothermal Resources Council Transactions, 33: 185-198.

Fritschle, Tobias; Daly, J. Stephen; Whitehouse, Martin J.; McConnell, Brian; Buhre, Stephan

2014-05-01

129

Li in minerals from the Ilimaussaq alkaline intrusion, South Greenland  

International Nuclear Information System (INIS)

Li was analysed by instrumental neutron activation analysis and Cerenkov counting in 120 mineral samples (30 species) from the Ilimaussaq alkaline intrusion, South Greenland. More than 0.23 wt.% Li (0.5 wt.% Li2O) is found in polylitionite, meptunite, riebeckite, Na-cookeite, ephesite, arfvedsonite, gerasimovskite and astrophyllite. Arfvedsonite (200-2500 ppm Li) carreis the bulk of Li in most of the highly alkaline rocks. Li-Mg and Li-F relations indicate that the distribution of Li is controlled by the structure of minerals, their absolute contents of Mg and F and the fractionation stage within the intrusion. Li is probably linked with F in the fluid state and this linkage continues into crystallising phases where Li occupies sites which also accommodate Mg. Li/Mg and LI/F ratios of Ilimaussaq rocks and minerals are higher than in equivalent materials from the Lovozero intrusion (Kola, Russia). The Li-Mg-Fe2+ geochemical association at Ilimaussaq (Fe2+>>Mg) and Lovozero (Fe2+mG) contrasts with the commercially important Li-rich but Mg-Fe2+-poor association found in certain granite pegmatites and greisenised granites. (au) (43 refs.)

130

Working memory and inhibitory control across the life span: Intrusion errors in the Reading Span Test  

OpenAIRE

The aim of this study was to examine to what extent inhibitory control and working memory capacity are related across the life span. Intrusion errors committed by children and younger and older adults were investigated in two versions of the Reading Span Test. In Experiment 1, a mixed Reading Span Test with items of various list lengths was administered. Older adults and children recalled fewer correct words and produced more intrusions than did young adults. Also, age-related differences wer...

Robert, Christelle; Borella, Erika; Fagot, Delphine; Lecerf, Thierry; Ribaupierre, Anik

2009-01-01

131

Rb-Sr isotopic constraints on the ages of the Mgeni and Nqwadolo Granites, Valley of a Thousand Hills, Natal  

International Nuclear Information System (INIS)

Rb-Sr isotopic data are presented for the various mineralogically distinct components of the Mgeni batholith and the Nqwadolo pluton. Orthopyroxene- and hornblende-bearing varieties of the Mgeni Granite provide an Rb-Sr errorchron date of 1029 ±57 Ma whereas the biotite-bearing variety provides an isochron date of 1001 ± 35 Ma. The Nqwadolo Granite samples define an isochron date of 1033 ± 18 Ma. These results, together with previously reported data, are interpreted as indicating intrusion of the Mgeni and Nqwadolo Granites at ? 1020 Ma. Older dates are thought to be artefacts of contamination of the Mgeni Granite melt, possibly with country rock of the Nagle Dam Formation. 17 refs., 5 figs., 3 tabs

132

Proposal for classification of the granitic rocks of the Ryoke belt in the Chubu and Kinki districts in view of hydrogen isotope study  

International Nuclear Information System (INIS)

The granitic rocks of Ryoke belt in Chubu and Kinki districts are classified into three groups based on the geological situation and the D/H-chemical composition relationship of coexisting biotite and hornblende: 1) gneissose granitic rocks such as Hiji and Tenryukyo type, 2) Inagawa granitic rocks, and 3) discordant granitic rocks such as Shinshiro, Hissori and Kisokoma types. The gneissose granitic rocks are closely associated with Ryoke metamorphic rocks, and constituted the original Ryoke plutono-metamorphic belt together with the metamorphic rocks. After the formation of the Ryoke plutono-metamorphic belt, Nohi ryolite erupted. Then, the Inagawa granitic rocks were intruded. The discordant granitic rocks are younger than the Inagawa granitic rocks. The features in the D/H-chemical composition relationship of respective groups are shown. The Ryoke metamorphic rocks show equilibrium state in the relationship when biotite and hornblende coexist. Muscovite in the metamorphic rocks seems to be also in equilibrium with coexisting biotite in regard to the hydrogen isotopes. The granitic rocks of Naegi type are distinctly different from the Ryoke granitic rocks. (Kako, I.)

133

Petrochemical characteristics of Serra do Meio alkaline granite (Campo Alegre de Lourdes - Bahia State)  

International Nuclear Information System (INIS)

The Serra do Meio granite outcrops near the town of Campo Alegre de Lourdes, north-northeast of Bahia State. The granite is intrusive into micachists, which are correlatives of the Salgueiro-Cachoeirinha Group (Early Proterozoic), during early to the syn-tectonic shear phase. The geological setting also comprises a phosphatic rock-bearing carbonatitic complex and gabbroid complexes with one of the main world resources of Fe-Ti-V. The granite mineralogical composition grades from Aegerine-augite alkali-feldspar granite/syenites to Leuco alcali-feldspar granite. The geochemical analysis shows SiO2-enrichment (67 to 76%), in alkalis (Na2+K2O, 7,5 to 12,5%), Nb (up to 680ppm), Zr (up to 2,390ppm), Y (up to 250ppm) e REE (up to 796ppm). The geochemical behaviour is peculiar to alkaline series, denoting a silica-oversaturated, potassium-rich, magma. The chondrite-normalized REE patterns display a first group with smooth slopes from the La to Lu, and a second one with negative slopes. Negative Eu anomalies are displayed in all the patterns. The first group is HREE-enriched, with low fractionation ratios. Samples with milonytic fabrics and higher fractionation ratios are related to the second group, suggesting the interaction of metassomatic fluids and the alkaline magma. Discriminant diagrams for Nb, Y and Rb, coupled with geophysical data, point to an intrusive granite in an extensional within a plate tectonic setting of attenuated continental crust. (author)

134

Archaean greenstone belts and associated granitic rocks - A review  

Science.gov (United States)

Archaean greenstone belts and associated granitic rocks comprise some of the most diverse rock types on the Earth's surface and were formed during the early stages of the development of the planet from Eoarchaean to Neoarchaean times - a period extending back from about 4000 to 2500 million years ago. Because of their great age, these rocks have received unprecedented attention from a wide spectrum of Earth scientists striving to learn more about the evolution of the Earth, including its crust, hydrosphere, atmosphere, the commencement of life, and the nature and distribution of mineral deposits. The knowledge gained thus far has accumulated incrementally, beginning with solid field-based studies, the latter being supplemented with increasingly advanced technological developments that have enabled scientists to probe fundamental questions of Earth history. Archaean granite-greenstone terranes display considerable variability of lithologies and geotectonic events, yet there are unifying characteristics that distinguish them from other geological environments. Most greenstone belts consist of a wide variety of volcanic and sedimentary rocks that reflect different evolutionary conditions of formation and all have invariably been influenced by subsequent geotectonic factors, including the intrusion of ultramafic, mafic and granitic complexes, resulting in widespread deformation, metamorphism, metasomatism, as well as mineralization. Geochemical and isotopic age determinations have shown how complex these ancient rocks are and efforts at understanding the nature and evolution of the hydrosphere, atmosphere and primitive life have made Archaean terranes exciting environments in which to study. Conflicting views as to the nature, history and origin of many of the rock types and events in Archaean terranes has been ongoing and stimulating. This review attempts to describe the main lithotypes and other characteristics of granite-greenstone belt geology and points to some areas where contrasting views have been expressed.

Anhaeusser, Carl R.

2014-12-01

135

Intrusion Detection System: Overview  

CERN Document Server

Network Intrusion Detection (NID) is the process of identifying network activity that can lead to the compromise of a security policy. In this paper, we will look at four intrusion detection approaches, which include ANN or Artificial Neural Network, SOM, Fuzzy Logic and SVM. ANN is one of the oldest systems that have been used for Intrusion Detection System (IDS), which presents supervised learning methods. However, in this research, we also came across SOM or Self Organizing Map, which is an ANN-based system, but applies unsupervised methods. Another approach is Fuzzy Logic (IDS-based), which also applies unsupervised learning methods. Lastly, we will look at the SVM system or Support Vector Machine for IDS. The goal of this paper is to draw an image for hybrid approaches using these supervised and unsupervised methods.

Alanazi, Hamdan O; Zaidan, B B; Zaidan, A A

2010-01-01

136

The Rb-Sr age of the Sundsta granite in the Western Pregothian tectonic mega-unit, south-western Sweden  

International Nuclear Information System (INIS)

The Sundsta granite is a reddish, acidic granite, situated in the Western Pregothian mega-unit in Vaermland, south-western Sweden. Its Rb-Sr whole-rock age is 1566+-39 Ma with an initial ratio 0f 0.705 +-0.003. The region is dominated by grey, migmatized granitoids presumably belonging to the Aamaal-I group which has ages of 1650-1700 Ma. The marked difference in degree of migmatization between these two rock-units may indicate that the intrusion of the Sundsta granite post-dates the main migmatization phase of the Aamaal-I granitoid in this region. (Authors)

137

Petrogenesis and magmatic evolution of ?130 Ma A-type granites in Southeast China  

Science.gov (United States)

A number of Late Mesozoic (?130 Ma) A-type granitic plutons have been identified in Southeast China. Here we investigate the petrogenesis of one of these granitic plutons in Southeast China, the Sanqingshan-Damaoshan (SD) granites in northeastern Jiangxi Province, using zircon U-Pb geochronology, Hf isotopic analyses, and major and trace element analyses. The SD granites are metaluminous to weakly peraluminous and show typical A-type affinity, which is characterized by high SiO2, Na2O + K2O, rare earth element (REE), high field strength element (HFSE) contents, Ga/Al and Fe# [FeOt/(FeOt + MgO)] values. Zircon grains from the SD granites and some other ?130 Ma A-type granites commonly contain oscillatory zoning 'cores' surrounded by unzoned to weakly zoned 'rims'. Detailed studies of zircons from the SD granites show that 'rims' are enriched in LREE, Th and U compared with 'cores'. Chondrite-normalized REE patterns of the 'cores' increase steeply from La to Lu and show pronounced Ce and Eu anomalies, while REE patterns of the 'rims' display higher REE abundances with flatter LREE patterns and moderate Ce anomalies. Nevertheless, Lu-Hf isotopic analyses and Ti-in zircon thermometer show similar characteristics between 'rims' and 'cores', indicating that the 'rims' may crystallize under the effect of internal magmatic hydrothermal fluids. U-rich 'rims' are more susceptible to Pb loss caused by self-irradiation, which may lead to significant younger U-Pb ages. As a result, U-Pb ages of zircon 'cores' (?130 Ma) represent crystallization ages of the SD granites. ?Hf(t) values of zircon grains from the SD granites are between -6.4 and -0.4 with Mesoproterozoic model ages (T2DM) ranging from 1.22 to 1.59 Ga, suggesting that the granites may be formed by partial melting of Proterozoic basement. Compared with other adjacent ?130 Ma A-type granitic plutons in SE China, the SD granites have similar geochemical characteristics and Hf isotopic compositions to those of Xiangshan, Daqiaowu, Yangmeiwan, and Tongshan granites, but different from the Baijuhuajian granite. ?Hf(t) values of the Baijuhuajian granites are higher than other granites, indicating significant participation of juvenile materials. These ?130 Ma A-type granites indicate a back-arc extension setting due to the roll-back of paleo-Pacific plate, where the crust and lithospheric mantle became progressively thinned. The upwelling of asthenosphere triggered the partial melting of crustal rocks and generated the Sanqingshan-Damaoshan, Tongshan, Daqiaowu and Yangmeiwan granitic plutons. With ongoing back-arc extension and increased subduction angle during the roll-back of subducted paleo-Pacific slab, the back-arc extension gradually intensified, resulting in significant additions of mantle juvenile materials to the crustal magma and the formation of the Baijuhuajian granite.

Sun, Fajun; Xu, Xisheng; Zou, Haibo; Xia, Yan

2015-02-01

138

Cretaceous evolution of the Adria-Europe plate boundary: succession of events recorded in granites and enclaves of the Moslava?ka Gora (Croatia)  

Science.gov (United States)

Complex Cretaceous S-type granitoid pluton, geotectonically related to an active continental margin, makes a central part of the Moslava?ka Gora (MG) crystalline and hosts two groups of enclaves. Cognate enclaves, genetically related to the granitoid host rocks, comprise different types of microgranular enclaves, tourmaline nodules, K-feldspar megacrysts and other inhomogenities found inside the two-mica granitoids. All of these enclaves provide evidence of the petrogenetic processes that took place inside the MG Cretaceous magmatic system. On the other hand, foreign enclaves, mostly xenoliths of metapelitic and metabasic rocks, hold information about the metamorphic events that preceded or were contemporaneous with the intrusion and solidification of the igneous body. Based on the age data gathered by earlier researchers of the MG crystalline and P-T data extracted from the study of Cretacoeus granitoids and their enclaves, it was possible to characterize multiple episodes of Cretaceous igneous and metamorphic evolution of the MG. Intrusion of the mantle-related mafic magma at pressures ~8 kbar and temperatures ~920 °C has been regarded as the oldest Cretaceous magmatic pulse (~110-90 Ma) recorded in the MG crystalline complex, leaving behind local occurrences of gabbroic rocks. Its relation to the medium-pressure metamorphic event recorded in amphibole-bearing xenoliths reaching ~8 kbar and max. ~800 °C has not been elucidated so far. It was followed by a younger LP-HT event (100-90 Ma), recorded in a sequence of partial melting reactions in the metapelitic rocks reaching granulite facies conditions (2-5 kbar, ~720-790 °C). Such melt-producing reactions documented in the km-sized metapelitic xenoliths point to the nature and extent of processes in the metapelitic source rocks that contributed to the overall production of the granitic magma in this setting. All of the aforementioned events preceded the Late Cretaceous intrusion of the central granitoid body and oscillations of igneous activity recored in the products of mixing and hybridization between granitoids and more mafic magmas (MME enclaves) and the onset of immiscibility (tourmaline nodules) nad the intrusion of leucogranites. According to our data, all of these pulses occurred in a low-pressure crustal setting (<3 kbar, 660-770 °C). Late Cretaceous peak of igneous activity in the MG system was accompanied by a second LP-HT metamorphic event (<2 kbar, <650 °C) that has been recorded in all MG crystalline lithologies and is correlated with the crystallization and cooling of the crystalline complex, following the intrusion of the central granitoid body. Fluids released by its crystallization led to fluid-assisted melting reactions in cm- to m-sized metapelitic enclaves, recording the interaction of granitoid host with the encapsulated fragments of metapelitic rocks and their role in the granite petrogenesis at Moslava?ka Gora. Data gathered by the study of different types of enclaves from the Moslava?ka Gora granitoid rocks are mutually consistent and reflect the complexity of Cretaceous evolution of a small and geotectonically still enigmatic crystalline fragment at the Adria-Europe plate boundary. This approach opens new perspectives for future research of the processes that took place in the mobile zone on the southeastern margins of Mesozoic Europe.

Petrinec, Zorica; Balen, Dražen

2014-05-01

139

Geochemistry of biotite granites from the Lamas de Olo Pluton, northern Portugal  

Science.gov (United States)

In the Central Iberian Zone (CIZ) extensive crustal recycling occurred during the post-thickening extension stage of the Variscan orogeny (~330-290 Ma). After the ductile deformation phase D3 (~320-300 Ma), characterized by the intrusion of large volumes of highly peraluminous granitic magmas, rapid and drastic tectonic changes at about 300 Ma gave rise to the brittle phase of deformation D4 that controlled the emplacement of Fe-K subalkaline granites (296-290 Ma; Dias et al. 1998). The Lamas de Olo Pluton (LOP) is controlled by NE-SW and NW-SE fracture systems, probably related to the Régua-Verin fault zone (Pereira, 1989). The LOP is a medium to coarse-grained, porphyritic biotite granite, accompanied by medium- to fine grained, porphyritic biotite granite (Alto dos Cabeços- AC) and a more leucocratic, fine-grained, slightly porphyritic biotite-muscovite granite (Barragens- BA). The contacts between LO and AC are generally diffuse, whereas those to BA are sharp. In fact, the BA granite can occur in dykes and sills cutting LO and AC. Microgranular enclaves and xenoliths are very rare. The LOP intrudes the Douro Group, presumably of Precambrian to Cambrian age, and two-mica granites from the Vila Real composite massif. The LOP granites consist of quartz, microcline, plagioclase, biotite, zircon, titanite, tourmaline apatite, fluorite, ilmenite, magnetite, and rutile, with muscovite in BA granite and rare allanite in the LO and AC granites. The plagioclase composition is of oligoclase (An12) - andesine (An35) for LO granite, albite (An9) - andesine (An30) for CA granite and albite (An5) - oligoclase (An20) for BA granite. There are decreases in: a) anorthite content from phenocryst to matrix plagioclase; b) Ba content from phenocryst to matrix microcline in all granites. The Fe2+ biotite has a composition similar to that of biotite from calc-alkaline to sub-alkaline rock series. The LO and AC granites are meta- to peraluminous with ASI variable between 1.05 and 1.21, and display isotopic signatures of (87Sr/86Sr)i = 0.7044-0.7077 and Nd = -2.2 to -1.1. Six samples of LO define a whole rock isochron age of 285±15 Ma with (87Sr/86Sr)i = 0.7051±0.001 (MSWD = 0.11). Two monazite analyses for the LO granite yield an weighted average 207Pb/235U age of 297.19±0.73 Ma, consistent with the preliminary ID-TIMS U-Pb analyses of two transparent and euhedral prisms of zircon that define a concordia age of 296.37 ±0.52 Ma (MSWD = 0.66). The linear trends of major and trace elements variation diagrams of LO and AC granites and their similar mean values of (87Sr/86Sr)i point, at this stage, to an involvement of mid-crustal sources, probably mixed with asthenospheric material. Therefore, LOP consists of post-D3 biotite granites installed in higher structural crustal levels, testifying the occurrence of a crustal growth episode after the major recycling processes that occurred during the deformation phase D3. We thank Prof. J.F. Santos and Dr. S. Ribeiro and Petrochron project (PTDC/CTE-GIX/112561/2009) for the Rb-Sr isotopic data obtained at LGI of University of Aveiro, Portugal. Dias, G. et al. 1998. Lithos, 45, 349-369. Pereira, E., 1989. Serviços Geológicos de Portugal.

Fernandes, Susana; Gomes, Maria; Teixeira, Rui; Corfu, Fernando

2013-04-01

140

Intrusion detection: systems and models  

Science.gov (United States)

This paper puts forward a review of state of the art and state of the applicability of intrusion detection systems, and models. The paper also presents a classfication of literature pertaining to intrusion detection.

Sherif, J. S.; Dearmond, T. G.

2002-01-01

141

Status of LLNL granite projects  

Energy Technology Data Exchange (ETDEWEB)

The status of LLNL Projects dealing with nuclear waste disposal in granitic rocks is reviewed. This review covers work done subsequent to the June 1979 Workshop on Thermomechanical Modeling for a Hardrock Waste Repository and is prepared for the July 1980 Workshop on Thermomechanical-Hydrochemical Modeling for a Hardrock Waste Repository. Topics reviewed include laboratory determination of thermal, mechanical, and transport properties of rocks at conditions simulating a deep geologic repository, and field testing at the Climax granitic stock at the USDOE Nevada Test Site.

Ramspott, L.D.

1980-12-31

142

Experimental and geochemical evidence for derivation of the El Capitan Granite, California, by partial melting of hydrous gabbroic lower crust  

Science.gov (United States)

Partial melting of mafic intrusions recently emplaced into the lower crust can produce voluminous silicic magmas with isotopic ratios similar to their mafic sources. Low-temperature (825 and 850°C) partial melts synthesized at 700 MPa in biotite-hornblende gabbros from the central Sierra Nevada batholith (Sisson et al. in Contrib Mineral Petrol 148:635 661, 2005) have major-element and modeled trace-element (REE, Rb, Ba, Sr, Th, U) compositions matching those of the Cretaceous El Capitan Granite, a prominent granite and silicic granodiorite pluton in the central part of the Sierra Nevada batholith (Yosemite, CA, USA) locally mingled with coeval, isotopically similar quartz diorite through gabbro intrusions (Ratajeski et al. in Geol Soc Am Bull 113:1486 1502, 2001). These results are evidence that the El Capitan Granite, and perhaps similar intrusions in the Sierra Nevada batholith with lithospheric-mantle-like isotopic values, were extracted from LILE-enriched, hydrous (hornblende-bearing) gabbroic rocks in the Sierran lower crust. Granitic partial melts derived by this process may also be silicic end members for mixing events leading to large-volume intermediate composition Sierran plutons such as the Cretaceous Lamarck Granodiorite. Voluminous gabbroic residues of partial melting may be lost to the mantle by their conversion to garnet-pyroxene assemblages during batholithic magmatic crustal thickening.

Ratajeski, Kent; Sisson, Thomas W.; Glazner, Allen F.

2005-08-01

143

Patherns in the rare earth elements of the Serra do Carambei granite (Parana) and the others associated ignous rocks  

International Nuclear Information System (INIS)

The rare earth elements (REE) distribution patters in igneous rocks of the Serra do Carambei Granite area (Parana) were a very important tool to elucidate the genetic processes and the cogenetic relationships between these rocks. The porphyroid facies of the Cunhaporanga Granitoid Complex has a REE distribution pattern characterized by decreasing concentrations in direction to the heavy rare earth elements (HREE) and the smooth Eu negative anomalie, compatible with amphibole fractionation during the magma ascent and the incipient plagioclase fractionation. The REE pattern of the Serra do Carambei Granite is characterized by the strong Eu negative anomalie, by the light rare earth element (LREE) depletion and by the HREE increase. This shape of the REE patterns is frequently observed in Sn-W granites, according to French authors. However in the igneous rocks of the Serra do Carambei Granite area this is not true. ''Rhyolite'' dytes intrusives in the Serra do Carambei Granite exhibit REE pattern similar to the wall rock, indicating then the same genetic processes. The Castro Group rhyolites have REE patterns with decreasing concentrations in direction to the HREE and smooth Eu negative anomalie. The REE distribution patterns is against the consanguinity between the ''rhyolites'' intruded in the Serra do Carambei Granite and the rhyolites of the Castro Group and also between these rhyolites and the above mentioned Granite. (author)

144

Spatial and temporal relationships between granites and porphyry copper deposits in northern Chile  

Science.gov (United States)

Chile is the leading copper producing country in the world, hosting ~30% of known worldwide copper reserves. Subduction-related magmatism in Chile has been ongoing since at least Mesozoic time, with progressive inland migration of the magmatic arc from the Jurassic coast eastward to the active western cordillera in the high Andes. Porphyry copper deposits (PCDs) in Chile are spatially and temporally related to emplacement of shallow, felsic to intermediate composition plutons that sourced the ore-forming magmas and mineralising fluids. However, not every such intrusion in Chile is associated with a mineralised deposit, suggesting that there are other controls on whether or not an intrusion hosts a PCD. Models for porphyry copper formation typically assume emplacement of these felsic to intermediate intrusions at shallow crustal levels (5-15 km depth) [1], but absolute constraints on emplacement depths for both mineralised and barren systems are lacking. In order to explore the relationship between granite emplacement depths and occurrences of PCDs in northern Chile, we have created a geospatial database that compares the age, geochemistry, and depth of mapped felsic to intermediate plutons (e.g. granites, tonalities, and diorites) with the locations of known PCDs, as well as major fault zones and volcanic centres. Emplacement depths have been calculated from published geochemical analyses using existing calibrations of the Al-in-hornblende barometer, which is widely used for calc-alkaline granitic rocks [2]. We are also developing a new experimental calibration of the barometer using a combination of piston cylinder experiments (5, 7, and 10 kbar), externally heated pressure vessel experiments (0.5-2 kbar), and electron microprobe analyses on a granitic sample of the Lluta batholith, collected in northern Chile. This improved Al-in-hornblende barometer, calibrated for shallow intrusions, will provide a viable alternative to estimating depths of PCD formation from fluid inclusions, which is often hampered by alternations between lithostatic and hydrostatic pressure. Furthermore, the results of this study will be broadly applicable to investigating the potential links between intrusion depth, PCD formation, and parameters such as regional tectonic patterns and fluid/melt interactions. References: [1] Sillitoe, 2010, Porphyry Copper Systems, Ec. Geol., 105, 3-41. [2] Anderson et al., 2008, Thermometers and Thermobarometers in Granitic Systems, Rev. Min. Geochem., 69, 121-142.

Jiskoot, Courtney; Mutch, Euan; Cooper, Frances; Tattitch, Brian; Matjuschkin, Vladimir; Blundy, Jon

2014-05-01

145

Gamma-spectrometric surveys in differentiated granites. II: the Joaquim Murtinho Granite in the Cunhaporanga Granitic Complex, Parana, SE Brazil; Levantamentos gamaespectrometricos em granitos diferenciados. II: O exemplo do Granito Joaquim Murtinho, Complexo Granitico Cunhaporanga, Parana  

Energy Technology Data Exchange (ETDEWEB)

Detailed mapping at the NW corner of the large Neo proterozoic Cunhaporanga Granitic Complex (CGC), Parana state, SE Brazil, redefined the Joaquim Murtinho Granite (JMG), a late intrusion in CGC with an exposed area of about 10 km{sup 2}, made up mainly by evolved 'alaskites' (alkali-feldspar leuco granites). This unit is in tectonic contact with the Neoproterozoic-Eocambrian volcano-sedimentary Castro Group, to the W, and is intrusive into other less evolved granitic units of the CGC to the E. Petrographically, JMG shows mainly mesoperthite and quartz, with subordinate amounts of altered micas and some accessory phases, mainly zircon. The equi to inequigranular granites are usually deformed with cataclastic textures, are often brecciated, and may have miarolitic structures. Formation of late albite, sericite, carbonate and hematite was caused by deuteric and hydrothermal alteration. A gamma-ray spectrometric survey at 231 stations which measured total counts (TC), Ueq K%, eU ppm and eTh ppm was used to construct several direct and derived maps. Compared to neighboring units the JMG has significant anomalies, especially in the TC, %K, eTh and eU maps, although the differences are less obvious in some derived maps. These evolved granites are enriched in these three elements. Geochemical behavior of K, Th and U is used to analyse the results observed in maps. Enhanced weathering under a subtropical climate with moderate to high average temperatures and heavy rainfall affects mainly feldspars and biotite, and may also destabilize most U and Th-bearing accessory phases. Th is most likely retained in restite minerals in soils, being relatively immobile, while part of U may migrate as uranyl ion in oxidizing media. K is especially affected by feldspar alteration to K-free clays (mainly kaolinite), and may be completely leached. Gamma-ray spectrometric methods are valid tools to study facies in granitic rocks, especially in those that are enriched in K, Th and U. (author)

Ferreira, Francisco Jose Fonseca [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Geologia. Lab. de Pesquisas em Geofisica Aplicada; Fruchting, Allan [Votorantim Metais, Sao Paulo, SP (Brazil)], e-mail: allan.fruchting@vmetais.com.br; Guimaraes, Gilson Burigo [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil). Dept. de Geociencias], e-mail: gburigo@ig.com.br; Alves, Luizemara Soares [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)], e-mail: luizemara@petrobras.com.br; Martin, Victor Miguel Oliveira; Ulbrich, Horstpeter Herberto Gustavo Jose [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias. Dept. de Mineralogia e Geotectonica], e-mail: vicmartin6@ig.com.br, e-mail: hulbrich@usp.br

2009-07-01

146

MORPHOMETRY OF ZIRCON FROM BETLIAR GRANITE  

OpenAIRE

Morphometrical analyse has been provided, using the method of [10] , on zircon from granite porphyry at Betliar. The result of this investigation indicate a comagmatic origin of Betliar and other granite bodies in the Gemericum. The source materila for at the granite magma formation originated by hybridization of crust-mantle rocks.

Jakabská Katarína

1997-01-01

147

Vertical zonality of fractionated granite plutons reflected in zircon chemistry: the Cínovec A-type versus the Beauvoir S-type suite  

Science.gov (United States)

We studied vertical changes in the chemical composition of zircon from two contrasting Variscan granite systems. The Beauvoir system (Massif Central, France) composed of three successive intrusions (B1, B2, B3) represents typical peraluminous S-type granite extremely enriched in P, F, Li, Rb, Cs, Be, Sn, Nb, Ta, and poor in Zr, Th, REE and Y. The Cínovec system (Krušné hory Mts/Erzgebirge, Czech Republic/Germany) composed of two successive intrusions (protolithionite granite, zinnwaldite granite) is only slightly peraluminous, P-poor, F, Li, Rb, Cs, U, Th, REE, Y, Sc, Sn, W, Nb, Ta-rich granite, which may be classified as A-type. In both localities, the most fractionated intrusions are located on the top of the system. Samples from borehole GPF-1 (Beauvoir) represent an 800 m long vertical section through the entire granite stock, while CS-1 borehole (Cínovec) reached a depth of 1600 m. Chemical compositions of zircons from both granite systems show distinct vertical zonality, but their shape and elemental speciation is highly contrasting. At Beauvoir, zircon shows a remarkable increase in Hf-content from 2-4 wt. % HfO2 (~0.03 apfu Hf) in the deepest B3-unit to 15-19 wt. % HfO2 (up to 0.18 apfu Hf) in the uppermost B1-unit. The highest contents of F, P, and U were detected in the intermediate unit B2 at a depth of 400-600 m. At Cínovec, Hf shows only moderate enrichment from ca. 2 wt. % HfO2 in the deeper protolithionite granite to 5-10 wt. % HfO2 in the uppermost part of the zinnwaldite granite. High contents of Th (3-8 wt. % ThO2) are entirely bound in the uppermost section of the granite copula to a depth of 200 m, but below this level the contents only sporadically exceed 1 wt. % ThO2. Concentrations of U, Y, HREE, Sc and Bi also reach their highest values in the uppermost parts of the zinnwaldite granite, but their decrease downward is much gentler. Extreme enrichment of outer zones of zircon crystals from some granites with Hf or high contents of Th, U, REE, Y, Nb and of some other elements in zircons from other localities is not considered to be a specific phenomenon characterizing melts of A- or S-type granite, but reflects a high degree of fractionation of systems rich in Na and F.

Breiter, Karel; Škoda, Radek

2012-11-01

148

Fission track age of apatite from the Jurassic and cretaceous granites in South Korea and its tectonic implications  

International Nuclear Information System (INIS)

Twenty-six apatite separates obtained from 35 Daebo and Bulgugsa granites in South Korea were dated and studied by fission tracks. Apparent ages for the two groups are generally similar and range from about 40 to 80 Myr, which are younger than the emplacement ages and indicate the times at which the granites cooled below about 1000C. Track length distributions suggest that the Daebo granites were emplaced in the katazone and/or mesozone and initially cooled slowly while the Bulgugsa granites were emplaced in the epizone and cooled more rapidly. The relationship between the apatite ages and topographic elevation of the samples in the northeast suggests that uplift was very slow before the Early Tertiary but has probably increased subsequently to a rate of at least 70 m/Myr in this area. (author)

149

Expansion of the granitic post-orogenic magmatism in the formation of Serrinha (Northeastern Bahia, B R), Sao Francisco craton  

International Nuclear Information System (INIS)

The Pedra Vermelha Granitic Massif, located at the North area of Serrinha Nucleus, presents a circular shape, being intrusive at the Archaean geoscience-magmatic basement rocks and the Paleoproterozoic volcano sedimentary sequences. The single zircon U-Pb dating yield a crystallization age of 2080 ± 8 Ma. The geological, petrographic al and litogeochemical characteristics of the studied rocks are similar to those of the Morro do Lopes granitic magmatism (2076 ± 6 a 2071 ± 6 Ma), which is located at the South area of this nucleus. These allow us to infer that those post-orogenic alkaline bodies are widespread throughout the Serrinha Nucleus and constitute its last Paleoproterozoic magmatic expression. (author)

150

Geochronological and geological studies on a granite of higher Himalaya, North-East of Manikaran, Himachal Pradesh  

International Nuclear Information System (INIS)

Rb-Sr whole-rock data is presented for a biotite-granite of Central Crystallines. The whole-rock isochron age is found to be 467 +- 45 m.y. This should represent the time of intrusion of the granite. A brief account of the geology and petrography is also presented. The age of the biotite is found to be 8.8 +- 2.0 m.y., which is the youngest Rb-Sr age reported so far for a mineral from the Himalaya. This fixes the period when the rocks of this area, after being heated and uplifted, cooled to a temperature of about 3000C. (author)

151

Why do granites stand out as high elevation features of the landscape ?  

Science.gov (United States)

We propose a simple mechanism to explain why granitic igneous intrusions, despite being denser than the rocks they usually intrude, stand out as topographic highs in the landscape. This mechanism is predicted to be far more important than hardness or erodibility variations in many cases. We derived a very simple expression for the relationship between isostatically-driven surface uplift and erosion rates as a function of surface rock density that implies that the denser the surface rocks the faster the isostatic rebound. Using a surface process model coupled to a flexural isostatic model, we show how variations in surface rock density may result in substantial differential isostatic rebound and thus surface uplift rate and topography. We demonstrate that the contribution of this isostatic effect can be distinguished from that arising from the stronger resistance of denser rocks to erosion by estimating the enhanced rate of erosion predicted by our theory through variations in cooling ages from low temperature thermochonometers. We illustrate our proposition through a large number of examples where variations in surface rock density may have led to differential uplift and topography, including various granitic intrusions, but also the exhumation of denser rocks such as basaltic intrusions or gneiss domes or the emergence of continental areas from below sea level at the transition between the subduction and collision phases at active plate margins. Predicted steady-state surface topography in an area intruded by four dense granites that appear as topographic highs. Note that the granites have the same resistance to erosion than the surrounding rocks; they are denser.

Braun, J.; Murray, K. E.; Reiners, P. W.; Simon-Labric, T.

2013-12-01

152

Interior intrusion alarm systems  

International Nuclear Information System (INIS)

In meeting the requirements for the safeguarding of special nuclear material and the physical protection of licensed facilities, the licensee is required to design a physical security system that will meet minimum performance requirements. An integral part of any physical security system is the interior intrusion alarm system. The purpose of this report is to provide the potential user of an interior intrusion alarm system with information on the various types, components, and performance capabilities available so that he can design and install the optimum alarm system for his particular environment. In addition, maintenance and testing procedures are discussed and recommended which, if followed, will help the user obtain the optimum results from his system

153

Intrusion detection system elements  

International Nuclear Information System (INIS)

This report highlights elements required for an intrusion detection system and discusses problems which can be encountered in attempting to make the elements effective. Topics discussed include: sensors, both for exterior detection and interior detection; alarm assessment systems, with the discussion focused on video assessment; and alarm reporting systems, including alarm communication systems and dislay/console considerations. Guidance on careful planning and design of a new or to-be-improved system is presented

154

Perimeter intrusion sensors  

International Nuclear Information System (INIS)

To obtain an effective perimeter intrusion detection system requires careful sensor selection, procurement, and installation. The selection process involves a thorough understanding of the unique site features and how these features affect the performance of each type of sensor. It is necessary to develop procurement specifications to establish acceptable sensor performance limits. Careful explanation and inspection of critical installation dimensions is required during on-site construction. The implementation of these activities at a particular site is discussed

155

Perimeter intrusion alarm systems  

International Nuclear Information System (INIS)

Paragraph 73.50(b)(4) of 10 CFR Part 73 requires at fuel reprocessing plants and other plants processing enriched U, 233U, or Pu that the isolation zone be monitored to detect intruders so that response by the security forces can be initiated. This guide describes six types of perimeter intrusion alarm systems and presents criteria for their performance and use as a means acceptable to NRC for meeting the regulations

156

Relations of zoned pegmatites to other pegmatites, granite, and metamorphic rocks in the southern Black Hills, South Dakota  

Energy Technology Data Exchange (ETDEWEB)

The pegmatite field and the Harney Peak Granite of the southern Black Hills, South Dakota, form an igneous system that progresses from slightly biotitic muscovite granite through layered pegmatitic granite, with alternating sodic and potassic rocks, to simple plagioclase-quartz-perthite pegmatites, and on to zoned pegmatites. Most of the country rocks are Lower Proterozoic mica schists that were isoclinally folded and metamorphosed to biotite and almandine grades before granitic activity began. At 1,700 Ga, intrusion of the Harney Peak Granite created a large dome in these rocks, a thermal aureole with a staurolite, a first sillimanite isograd, and a small area of metamorphism above the second sillimanite isograd. The estimated pressure is 3.7 kbar. The zoned pegmatites have a strong tendency to occur in clusters, and the types of pegmatites are different in different clusters. A less obvious tendency is a regional zonation in which rare-mineral pegmatites become more abundant and muscovite pegmatites less abundant toward the outskirts of the region. The composition of the granite indicates that its magma originated by partial melting of metasedimentary mica schists similar to those at the present surface. The pegmatitic nature of most of the granite probably reflects exsolution of an aqueous phase. The resulting processes continued into the simple pegmatites and zoned pegmatites, which are 4% and 0.5% of the exposed granitic rocks. For rare-element pegmatites, residual concentration in granitic magma can account for their modest contents of Be, Sn, Ta, Nb, and Cs, but Li presents complications because a large share of the Li in the exposed parts of the system is in Li-rich zoned pegmatites.

Norton, J.J. (Geological Survey, Denver, CO (USA)); Redden, J.A. (Geological Survey, Denver, CO (USA) South Dakota School of Mines and Technology, Rapid City (USA))

157

Intensive low-temperature tectono-hydrothermal overprint of peraluminous rare-metal granite: a case study from the Dlhá dolina valley (Gemericum, Slovakia)  

Science.gov (United States)

A unique case of low-temperature metamorphic (hydrothermal) overprint of peraluminous, highly evolved rare-metal S-type granite is described. The hidden Dlhá dolina granite pluton of Permian age (Western Carpathians, eastern Slovakia) is composed of barren biotite granite, mineralized Li-mica granite and albitite. Based on whole-rock chemical data and evaluation of compositional variations of rock-forming and accessory minerals (Rb-P-enriched K-feldspar and albite; biotite, zinnwaldite and di-octahedral micas; Hf-(Sc)-rich zircon, fluorapatite, topaz, schorlitic tourmaline), the following evolutionary scenario is proposed: (1) Intrusion of evolved peraluminous melt enriched in Li, B, P, F, Sn, Nb, Ta, and W took place followed by intrusion of a large body of biotite granites into Paleozoic metapelites and metarhyolite tuffs; (2) The highly evolved melt differentiated in situ forming tourmaline-bearing Li-biotite granite at the bottom, topaz-zinnwaldite granite in the middle, and quartz albitite to albitite at the top of the cupola. The main part of the Sn, Nb, and Ta crystallized from the melt as disseminated cassiterite and Nb-Ta oxide minerals within the albitite, while disseminated wolframite appears mainly within the topaz-zinnwaldite granite. The fluid separated from the last portion of crystallized magma caused small scale greisenization of the albitite; (3) Alpine (Cretaceous) thrusting strongly tectonized and mylonitized the upper part of the pluton. Hydrothermal low-temperature fluids enriched in Ca, Mg, and CO2 unfiltered mechanically damaged granite. This fluid-driven overprint caused formation of carbonate veinlets, alteration and release of phosphorus from crystal lattice of feldspars and Li from micas, precipitating secondary Sr-enriched apatite and Mg-rich micas. Consequently, all bulk-rock and mineral markers were reset and now represent the P-T conditions of the Alpine overprint.

Breiter, Karel; Broska, Igor; Uher, Pavel

2015-02-01

158

Colorectal cancer in younger population: our experience  

International Nuclear Information System (INIS)

Objective: To promote awareness regarding increased occurrence of colorectal cancer in younger population and its clinicopathological features compared to older patients. Methods: The cross-sectional study was conducted from February 2010 to January 2011 on patients with diagnosis of colorectal carcinoma admitted through emergency or outpatient departments to Surgical Unit 5, Civil Hospital, Karachi. Data regarding age, gender, presentation, site of tumour, surgery performed and Dukes staging was collected and analysed. Results: A total of 23 patients were operated during the study period: 13 (56.52%) males and 10 (43.47%) females. Of them 12 (52.17%) were below the age of 40 years, while 3 (13.04%) patients were in the 11-20 age group. In 7 (30.4%) patients, tumour was irresectable at the time of presentation so a palliative procedure (diversion colostomy or ileostomy) was performed. There was a higher proportion of younger patients with metastatic disease at the time of presentation (n=9; 75%) while 10 out of 12 patients in the younger age group (83.3%) had a tumour of left colon, particularly rectum. Conclusion: Although colorectal cancer is usually a disease of older patients, it is increasingly becoming more common in younger population. Data suggests a leftward distribution for colorectal carcinoma and that younger patients present with more advanced disease and poorer prognosis. (author)

159

Southern complex: geology, geochemistry, mineralogy, and mineral chemistry of selected uranium- and thorium-rich granites  

International Nuclear Information System (INIS)

Four major rock groups are defined in the Southern Complex: the Bell Creek Granite (BCG), the Clotted Granitoids (CGR), the Albite Granite (AGR), and the Migmatite Complex. Metatexites of the Migmatite Complex are the oldest rocks and include paleosome of a metasedimentary and metavolcanic protolith represented by Banded Iron Formation, Banded Amphibolite, and Banded Gneisses, and interlayered or crosscutting leucogranites. The CGR span the range from metatexite to diatexite and represent in-situ partial melting of metapelitic layers in the protolith during intrusion of the BCG. The BCG cuts the migmatites, is locally cut by the CGR, and was derived by partial melting of a dominantly metasedimentary protolith at some depth below the presently exposed migmatites during a regional tectonothermal event. The Albite Granite is a 2km diameter, muscovite-fluorite-columbite-bearing intrusive stock that cuts all other major units. The thorium history of the BCG is a function of the history of monazite. The thorium history of the CGR is also dominated by monazite but the thorium content of this unit cannot be entirely accounted for by original restite monazite. The uranium history of the BCG and CGR was dominated by magmatic differentiation and post magmatic, metamorphic and supergene redistributions and is largely independent of the thorium history. The thorium and uranium history of the AGR was dominated by magmatic/deuteric processes unlike the BCG and CGR unlike the BCG and CGR

160

Additional Rb-Sr age determinations of mineral- and whole rock samples from the Leuchtenberg and Flossenbuerg granite (NE Bavaria)  

International Nuclear Information System (INIS)

Geochemical and geochronological studies on the Leuchtenberg and Flossenbuerg granite intrusions led to the conclusion that granitic magmas can dwell in the crust for periods of about 30 m.y. without taking up any noticeable amounts of Sr from the enclosing rocks. As this affirmation is strongly dependent on the reliability of the age determinations, additional measurements (7 mineral and 3 whole rock analyses) were carried out to strengthen the original data. An isochron giving an age of 313 +- 9 (1 sigma) m.y. and a Sr87/Sr86-initial ratio of 0.07068 +- 0.0005 (1 sigma) was obtained from measurements on 6 samples from an outcrop in the central portion of the Leuchtenberg granite (Laemmersdorf quarry). Both of these results correspond, within the limits of error, with previously obtained values. Analyses of apatite concentrates from both granite massifs confirm the originally obtained Sr87/Sr86-initial ratios. The certainty of the isochron data is enhanced through the combined evaluation of the present mineral and whole rock measurements with the earlier measurements. The original concept of the behaviour of granitic magmas in the earths crust is strengthened by this data. The present results and the whole rock analyses of 1974 show that the Sr-isotope distribution in the Leuchtenberg granite was, within the limits of error, homogenous. (orig.)

161

Intrusive growth of sclerenchyma fibers  

OpenAIRE

Intrusive growth is a type of cell elongation when the rate of its longitudinal growth is higher than that of surrounding cells; therefore, these cells intrude between the neighboring cells penetrating the middle lamella. The review considers the classical example of intrusive growth, e.g., elongation of sclerenchyma fibers when the cells achieve the length of several centimeters. We sum the published results of investigations of plant fiber intrusive growth and present some features of intru...

Snegireva, A. V.; Ageeva, M. V.; Amenitskii, S. I.; Chernova, T. E.; Ebskamp, M.; Gorshkova, T. A.

2010-01-01

162

Natural radionuclide distribution in Brazilian commercial granites  

Energy Technology Data Exchange (ETDEWEB)

The dimension stones sector in Brazil produces several varieties of granites, marbles, slates and basalts. More than half of this production corresponds to around 200 different commercial types of granites with specific names, geographical and geological origins and mineral compositions. The well-known natural radioactivity present in rocks, where high radiation levels are associated with igneous rocks such as granite, can be used to determine their general petrologic features. This subject is important in environmental radiological protection, since granites are widely used as building and ornamental stones. In this paper, it is applied to correlate the petrographic characteristics of commercial granites with their corresponding dose rates for natural radioactivity. Amounts of thorium, uranium and potassium concentrations have been reported in several Brazilian commercial granite samples.

Anjos, R.M. [Instituto de Fisica da Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no, Gragoata, 24210-340 Niteroi, RJ (BR)]. E-mail: meigikos@if.uff.br; Veiga, R. [Instituto de Fisica da Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no, Gragoata, 24210-340 Niteroi, RJ (BR); Soares, T. [Instituto de Fisica da Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no, Gragoata, 24210-340 Niteroi, RJ (BR); Santos, A.M.A. [Fundacao Jorge Duprat Figueiredo de Seguranca e Medicina do Trabalho-Fundacentro, C.P. 11484, 05499-970 Sao Paulo, SP (BR); Aguiar, J.G. [Fundacao Jorge Duprat Figueiredo de Seguranca e Medicina do Trabalho-Fundacentro, C.P. 11484, 05499-970 Sao Paulo, SP (BR); Frasca, M.H.B.O. [Instituto de Pesquisas Tecnologicas do Estado de Sao Paulo-IPT, Av. Prof. Almeida Prado 532, Cidade Universitaria, 05508-901 Sao Paulo, SP (BR); Brage, J.A.P. [Instituto de Fisica da Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no, Gragoata, 24210-340 Niteroi, RJ (BR); Uzeda, D. [Instituto de Fisica da Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no, Gragoata, 24210-340 Niteroi, RJ (BR); Mangia, L. [Instituto de Fisica da Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no, Gragoata, 24210-340 Niteroi, RJ (BR); Facure, A. [Instituto de Fisica da Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no, Gragoata, 24210-340 Niteroi, RJ (BR); Mosquera, B. [Instituto de Fisica da Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no, Gragoata, 24210-340 Niteroi, RJ (BR); Carvalho, C. [Instituto de Fisica da Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no, Gragoata, 24210-340 Niteroi, RJ (BR); Gomes, P.R.S. [Instituto de Fisica da Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no, Gragoata, 24210-340 Niteroi, RJ (BR)

2005-06-01

163

Extra-terrestrial igneous granites and related rocks: A review of their occurrence and petrogenesis  

Science.gov (United States)

The telluric planets and the asteroid belt display the same internal structure with a metallic inner core and a silicate outer shell. Experimental data and petrological evidence in silicate systems show that granite can be produced by extreme igneous differentiation through various types of igneous processes. On Moon, 4.4-3.9 Ga granite clasts display dry mineral assemblages. They correspond to at least 8 discrete intrusive events. Large K/Ca enrichment and low REE abundances in granite relative to KREEP are consistent with silicate liquid immiscibility, a process observed in melt inclusions within olivine of lunar basalts and in lunar meteorites. Steep-sided domes identified by remote sensing can represent intrusive or extrusive felsic formations. On Mars, black-and-white rhythmic layers observed on the Tharsis rise along the flanks of the peripheral scarps of the Tharsis Montes giant volcanoes suggest the possible eruption of felsic pyroclastites. Though no true granites were found so far in the Martian SNC meteorites, felsic glasses and mesostases were identified and a component close to terrestrial continental (granitic) crust is inferred from trace element and isotope systematics. Venus has suffered extensive volcanic resurfacing, whereas folded and faulted areas resemble terrestrial continents. Near large shield volcanoes, with dominant basaltic compositions, steep-sided domes have been interpreted as non-degassed silicic extrusions. The hypothesis of a granitic component is "tantalising". Extra-terrestrial granite is frequently found as clasts and mesostases in asteroidal meteorites. Porphyritic textures, with alkali feldspar crystals up to several centimetres in size, were observed in silicate enclaves within iron meteorites. In the chondrite clan, polymict breccias can contain granitic clasts, whose provenance is debated. One clast from the Adzhi-Bogdo meteorite yields a 4.53 ± 0.03 Ga Pb-Pb age, making it the oldest known granite in the solar system. The vast majority of granitic materials recognised so far in the extra-terrestrial record are characterised by ferroan A-type compositions, characterised by high to very high K2O and medium CaO contents, sodic varieties being exceedingly rare. Textural evidence of graphic quartz-alkali feldspar intergrowths within crystallised products suggests that they are igneous in origin and crystallised quickly from a liquid. In water-depleted to water-free environments, fluorine and chlorine can play significant roles, as their effects on liquidus temperatures and crystallising assemblages are nearly identical to those of water. The distribution of alkalis and alkaline earths cannot be related only to extensive crystal fractionation, but is likely induced by supplementary silicate liquid immiscibility. Medium-temperature silicate liquid immiscibility is well known as a mode of differentiation in experimental petrology studies at very low pressures on systems dominated by Fe, Ti, K, and P as major elements. The ultimate question is, therefore, not whether granite (s.l.) occurs in any given planetary body, but if sufficient volumes of granitic materials could have been produced to constitute stable continental nuclei.

Bonin, Bernard

2012-11-01

164

DRM – Intrusion or Solution?  

OpenAIRE

DRM could be the solution to the content industry’s P2P dilemma, but content owners’ desire to monitor and control the consumer’s use of content can be perceived as an intrusion of privacy. High control makes consumers less active and low control invites them to experiment and to gain experience. Digital music files can easily be spread. Therefore legal services prefer keeping control over the music. This study reveals that consumers are one step ahead of the content industry, finding w...

Blomqvist, Ulf; Fritzell, Michael; Olofsson, Marcus

2005-01-01

165

Acoustic emission intrusion detector  

Science.gov (United States)

An intrusion detector is provided for detecting a forcible entry into a secured structure while minimizing false alarms. The detector uses a piezoelectric crystal transducer to sense acoustic emissions. The transducer output is amplified by a selectable gain amplifier to control the sensitivity. The rectified output of the amplifier is applied to a Schmitt trigger circuit having a preselected threshold level to provide amplitude discrimination. Timing circuitry is provided which is activated by successive pulses from the Schmitt trigger which lie within a selected time frame for frequency discrimination. Detected signals having proper amplitude and frequency trigger an alarm within the first complete cycle time of a detected acoustical disturbance signal.

Carver, Donald W. (Knoxville, TN); Whittaker, Jerry W. (Knoxville, TN)

1980-01-01

166

Hybrid network intrusion detection  

Science.gov (United States)

We report on a machine learning classifier that can be used to discover the patterns hidden within large networking data flows. It utilizes an existing intrusion detection system (IDS) as an oracle to learn a faster, less resource intensive normalcy classifier as a front-end to a hybrid network IDS. This system has the capability to recognize new attacks that are similar to known attack signatures. It is also more highly scalable and distributable than the signature-based IDS. The new hybrid design also allows distributed updates and retraining of the normalcy classifier to stay up-to-date with current threats.

Tahmoush, David

2014-05-01

167

Distributed Intrusion Detection System  

Science.gov (United States)

Internet worms and other malicious code often scan firewalls to determine which ports are unprotected. While firewall users have access to their port scanning data in the form of log files, most do not make use of it. The Distributed Intrusion Detection System remotely monitors trends in worldwide port scanning, and the data it has collected is available at this site. The data can be used by Internet professionals for early detection of worms or for implementing improved security measures. Firewall users can contribute to this project by downloading the free DShield Client, which automatically sends log reports for inclusion in worldwide data or by submitting logs online via a Web interface.

168

Granite Sludge Reuse in Mortar and Concrete  

OpenAIRE

The disposal of solid wastes produced in granite industry to the environment without any treatment cause not only economical but also serious environmental problems. In this study Granite Powder (GP) which produced as solid waste from the cutting and polishing of granite rocks was reused as additive to mortar and concrete cement. Incorporation of GP in mortar and concrete in ratios of 10, 20, 30 wt.% improved mortar and concrete compressive strengths and the concrete workability. The experime...

Al- Hamaiedeh, Husam D.; Khushefati, Waleed H.

2013-01-01

169

Age of granites of Wrangel Island metamorphic complex  

Science.gov (United States)

Within huge arctic shelf of Eastern-Siberian and Chukchi seas the metamorphic basement (Wrangel complex, Berri Formation) is exposed only on the Wrangel Island. There are different points of views on the age of metamorphic rocks of Wrangel complex (Berri Formation): (1) Neoproterozoic (Kameneva, 1970; Ageev, 1979; Kos'ko et al., 1993, 2003), (2) Devonian (Til'man et al., 1964, 1970; Ganelin, 1989). Metamorphic basement is represented by stratified complex, composed of dislocated metavolcanic, metavolcaniclastic and metasedimentary rocks (schists, metasandstones, metaconglomerated) with single lenses and layers of carbonate rocks (Wrangel Island…, 2003). Among basement rocks in the central part of Wrangel Island there are felsic intrusive bodies. They form small tabular bodies from tens centimeters to 70-80 meters in thickness, rarely dikes and small stocks (up to 20 x 30 m) and are composed of granite-porphyres, rarely muscovite porphyr-like granites and granosyenites (Wrangel Island…, 2003). The age of intrusions allow to determine the age of basement formation. Earlier the age of intrusions was determined by different methods and correlated to the boundary between Neoproterozoic and Paleozoic: K-Ar 570-603 Ma, Pb-Pb 590±50 Ma (S.M. Pavlov, Institute of Precambrian Geology and Geochronology, USSR Academy of Sciences), Rb-Sr 475±31 Ma (I.M.Vasil'eva, Institute of Precambrian Geology and Geochronology, USSR Academy of Sciences), U-Pb 609, 633, 677 Ma (Geological Survey of Canada) (Wrangel Island…, 2003; Kos'ko et al., 1993; Cecile et al., 1991). In the lower part of metamorphic rocks of Wrangel complex there are conformable tabular bodies of gneissosed and foliated granitoides. The latter are meramorphosed and transformed in biotite-muscovite-feldspar-quartz-sericite and muscovite-feldspar-quartz-sericite gneisses and schists, where relics of primary minerals (quartz, plagioclase, potassium feldspar, rarely biotite and muscovite) and equigranular granitic texture are preserved. Accessory minerals of granitoides are zircon, sphene, apatite. During field work of 2006 year the probes for U-Pb SHRIMP zircon datings were collected (upper reaches of Khishchnikov River). Dating was carried out on SHRIMP-II in the Center of Isotopic Studies of Federal State Unitary Enterprize "A.P.Karpinsky Russian Geological Research Institute". Wheited mean ages of zircons from three probes are: 702±3 Ma (N=19), 701±7 Ma (N=3), 707±4 Ma (N=25). They indicate Neoproterozoic age of granitoides. Furthermore, some zircons contain inherited cores, for which following datings were obtained: 1.1; 1,21; 1.107; 1.2-1,4; 1.58; 1.8; 2.6 Ga. These data allow supposing the presence of ancient (Neoproterozoic-Mesoproterozoic) rocks in the basement of Wrangel Island and their participation in the melting process during granite magmas formation. The work was supported by Russian Fund of Basic Researhes projects 13-05-00249, 14-05-00031, Scientific school NSh-2981.2014.5.

Luchitskaya, Marina; Sergeev, Sergey; Sokolov, Sergey; Tuchkova, Marianna

2014-05-01

170

Spatial Intrusion of Mining  

Directory of Open Access Journals (Sweden)

Full Text Available The Spatial Intrusion of Mining is a conceptual of space or the location component. The Mining can be viewed as the data about the objects which are located in physical space. It may be implemented by a specific location attributes by latitudes and longitudes and also by more implicitly included about the partitioning of the databases which are based on the location. The spatial data bases and ware houses were the data is accesses by by using the queries containing directions, adjacent and contained in. Generally the data is stored in the spatial databases which contain spatial data and about the non spatial data about the objects. The ware houses and databases are stored by using the spatial data structures using the topological information. The spatial intrusion describes with both spatial and non spatial attributes. It mainly concentrates on location type of attributes which must be included and identifies a precise point. The logical address such as street number, zip code. The objects are located by different locations and some sort of translation between one attribute and the other which is needed to perform the spatial operations between the objects. This paper describes an algorithm for the retrieval of the objects from the non spatial objects which are stored in relational databases and the spatial objects are stored in some of the spatial data structures. In general the tuple represents the spatial object and the link to the tuple represents the corresponding position in the non spatial tuple.

SarathChand P.V

2011-09-01

171

Geochemistry and petrogenesis of the proterozoic granites from Jhabua and Dhar districts, Madhya Pradesh, India and their bearing on uranium mineralisation  

International Nuclear Information System (INIS)

In the western part of Madhya Pradesh a number of small plutonic granites occur as intrusive into the gneisses and Aravalli metasediments. Granites are of grey, pink colour and gneissic varieties. Mineralogically, the granites are two mica bearing. Chemically they are K2O rich, calc-alkaline, metaluminous to peraluminous and differentiated in nature. Tectonically they are volcanic arc types with an affinity to syn-collisional setup. Basement reactivation may be the cause of the emplacement of these granites as the area is traversed by a number of basement lineaments. They are enriched in light REE with Ce/Yb ratio ranging from 1.4 to 8.4. Negative Eu anomaly (Eu/Eu* 0.2 to 0.8) suggests that they are fractionated. High Th/U ratio (1-18) indicates that uranium has been leached out. Hence the overlying infratrappeans hold potential for litho/structural controlled uranium mineralisation.(author)

172

Field characteristics, petrography, and geochronology of the Hohonu Batholith and the adjacent Granite Hill Complex, North Westland, New Zealand  

International Nuclear Information System (INIS)

Detailed geological mapping, petrography, geochemistry and geochronological studies in the Hohonu Batholith, North Westland, have identified 10 granitoid plutons emplaced during three intrusive episodes. The earliest episode is represented by a single dated Paleozoic pluton, Summit Granite (new) (381.2 ± 7.3 Ma), which is correlated with a discrete pulse of Mid-Late Devonian plutonism recognised in the Karamea Batholith. The undated Mount Graham Granite (new) is also likely to be Paleozoic, based on chemical and petrographic characteristics. The bulk of the batholith (seven plutons) was emplaced in the mid Cretaceous (114-109 Ma) and comprises two related, yet distinct, geochemical suites, which correlate with the previously defined Rahu Suite. The plutons identified are (from north to south): Pah Point Granite; Jays Creek Granodiorite (new); Uncle Bay Tonalite; Te Kinga Monzogranite; Deutgam Granodiorite; Turiwhate Granodiorite (new); and Arahura Granite (new). Mid-Cretaceous plutonism in the Western Province is considered to be the result of crustal thinning and extension following overthickening during collision of the Early Cretaceous Median Tectonic Zone volcanic arc. Late Cretaceous alkaline activity is represented by the emplacement of the A-type French Creek Granite at 1.7 ± 1.8 Ma, contemporaneous with intrusion of a major swarm of doleritic-lamprophyric dikes - the Hohonu Dike Swarm. These events correlate with the first appearance of oceanic crust in the irst appearance of oceanic crust in the Tasman Sea. The Granite Hill Complex is a suite of amphibolite facies gneisses occurring as an uplifted wedge between the Alpine Fault nd the Hohonu Batholith. These gneisses are considered to represent an extension of the Fraser Complex to the south. A detailed understanding of their geological affinities and history is yet to be established. (author). 66 refs., 7 figs., 3 tabs

173

Contrasting Structures and Deformational History of Syntectonic Granites of Campina Grande and Serra Redonda, Borborema Province, NE Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available The Campina Grande and Serra Redonda Granites are intrusive along the contact of the Paleoproterozoic basement(Alto Moxotó Domain with the Tonian gneisses (Alto Pajeú Domain of the Borborema Province (northeast Brazil. TheCampina Grande Granite (U-Pb age = 581± 2 Ma shows a concentric oval-shaped structure whereas the Serra RedondaGranite (U-Pb age = 576 ± 3 Ma has a tabular shape, elongated in the NE-SW direction. The plutons are separated bythe left-lateral Galante transcurrent shear zone. In this study, the anisotropy of magnetic susceptibility (AMS was appliedto 64 outcrops of granites to determine the internal structures of these plutons and to explore the relationship betweenmagmatism and deformation in an orogenic setting. The magnetic fabrics are concordant with the metamorphic structure ofthe host rocks. Strike-slip shear zones controlled the emplacement of the Serra Redonda Granite, as indicated by sigmoidalfoliation, defining shear bands associated with the Galante shear zone. In contrast, the magmatic/magnetic fabric of theCampina Grande granite seems to have been produced by body (ascensional forces. The pluton displays an inward dipping, concentric planar fabric parallel to the wall rock contact and lineations highly oblique to the foliation trend. The fabric of the Campina Grande pluton is consistent with a magma moving over a ramp dipping to southwest, with the lineation at high angle to the NE-trending flow direction. The contrasting structures of the plutons reflect the episodic nature of orogenic deformation, which was punctuated by the alternation of weak and strong strains, affecting the fabric development of the syntectonic intrusions.

Sérgio Wilians de Oliveira Rodrigues

2011-04-01

174

Radioactive waste disposal in granite  

International Nuclear Information System (INIS)

The principal geotechnical problems in selecting a repository site for radioactive waste disposal in granite are to evaluate the suitability of the rock mass in terms of: (1) fracture characteristics, (2) thermomechanical effects, and (3) fracture hydrology. Underground experiments in a mine in Sweden have provided an opportunity to study these problems. The research has demonstrated the importance of hydrogeology and the need to improve predictions of the thermomechanical behavior of fractured rocks. To characterize a site, measurements made from the surface must be supplemented by extensive subsurface experiments. Much effort is needed to generate the technology required for the development of waste repositories

175

Status of the GRANIT facility  

CERN Document Server

The GRANIT facility is a follow-up project, which is motivated by the recent discovery of gravitational quantum states of ultracold neutrons. The goal of the project is to approach the ultimate accuracy in measuring parameters of such quantum states and also to apply this phenomenon and related experimental techniques to a broad range of applications in particle physics as well as in surface and nanoscience studies. We overview the current status of this facility, the recent test measurements and the nearest prospects.

Roulier, Damien; Baessler, Stefan; Clément, Benoît; Morton, Daniel; Nesvizhevsky, Valery; Pignol, Guillaume; Rebreyend, Dominique

2014-01-01

176

Rb-Sr age of Godhra and related granites, Gujrat, India  

International Nuclear Information System (INIS)

Rubidium and strontium determinations are reported for Godhra and geographically related granites from central Gujarat. The whole rock data define a Rb-Sr isochron corresponding to a common age of 955 +- 2O m.y. and initial Sr ratio of 0.7130 +- 0.0O1. This age is distinctly older than the age of 735 m.y. reported for the Erinpura suite of rocks from Mount Abu in western Rajasthan and from Idar in nothern Gujarat. There are at least two generations of post-Delhi intrusive rocks in the Gujarat precambrian. Boitites associated with these granites have the same age as the whole-rocks within experimental error indicating the absence of significant metamorphic heating since the time of emplacement. It is significant that rocks of similar age occur in the Rajasthan Precambrian mainly in the axial zone of the Aravalli Mountains. (author)

177

Rapid deployment intrusion detection system  

International Nuclear Information System (INIS)

A rapidly deployable security system is one that provides intrusion detection, assessment, communications, and annunciation capabilities; is easy to install and configure; can be rapidly deployed, and is reusable. A rapidly deployable intrusion detection system (RADIDS) has many potential applications within the DOE Complex: back-up protection for failed zones in a perimeter intrusion detection and assessment system, intrusion detection and assessment capabilities in temporary locations, protection of assets during Complex reconfiguration, and protection in hazardous locations, protection of assets during Complex reconfiguration, and protection in hazardous locations. Many DOE user-need documents have indicated an interest in a rapidly deployable intrusion detection system. The purpose of the RADIDS project is to design, develop, and implement such a system. 2 figs

178

Conventional U-Pb dating versus SHRIMP of the Santa Barbara Granite Massif, Rondonia, Brazil  

Science.gov (United States)

The Santa Ba??rbara Granite Massif is part of the Younger Granites of Rondo??nia (998 - 974 Ma) and is included in the Rondo??nia Tin Province (SW Amazonian Craton). It comprises three highly fractionated metaluminous to peraluminous within-plate A-type granite units emplaced in older medium-grade metamorphic rocks. Sn-mineralization is closely associated with the late-stage unit. U-Pb monazite conventional dating of the early-stage Serra do Cicero facies and late-stage Serra Azul facies yielded ages of 993 ?? 5 Ma and 989 ?? 13 Ma, respectively. Conventional multigrain U-Pb isotope analyses of zircon demonstrate isotopic disturbance (discordance) and the preservation of inherited older zircons of several different ages and thus yield little about the ages of Sn-granite magmatism. SHRIMP U-Pb ages for the Santa Ba??rbara facies association yielded a 207Pb/206Pb weighted-mean age of 978 ?? 13 Ma. The textural complexity of the zircon crystals of the Santa Ba??rbara facies association, the variable concentrations of U, Th and Pb, as well as the mixed inheritance of zircon populations are major obstacles to using conventional multigrain U-Pb isotopic analyses. Sm-Nd model ages and ??Nd (T) values reveal anomalous isotopic data, attesting to the complex isotopic behaviour within these highly fractionated granites. Thus, SHRIMP U-Pb zircon and conventional U-Pb monazite dating methods are the most appropriate to constrain the crystallization age of the Sn-bearing granite systems in the Rondo??nia Tin Province.

Sparrenberger, I.; Bettencourt, J.S.; Tosdal, R.M.; Wooden, J.L.

2002-01-01

179

Passive intrusion detection system  

Science.gov (United States)

An intrusion detection system is described in which crystal oscillators are used to provide a frequency which varies as a function of fluctuations of a particular environmental property of the atmosphere, e.g., humidity, in the protected volume. The system is based on the discovery that the frequency of an oscillator whose crystal is humidity sensitive, varies at a frequency or rate which is within a known frequency band, due to the entry of an intruder into the protected volume. The variable frequency is converted into a voltage which is then filtered by a filtering arrangement which permits only voltage variations at frequencies within the known frequency band to activate an alarm, while inhibiting the alarm activation when the voltage frequency is below or above the known frequency band.

Laue, E. G. (inventor)

1980-01-01

180

Meltwater routing and the Younger Dryas  

OpenAIRE

The Younger Dryas—the last major cold episode on Earth—is generally considered to have been triggered by a meltwater flood into the North Atlantic. The prevailing hypothesis, proposed by Broecker et al. [1989 Nature 341:318–321] more than two decades ago, suggests that an abrupt rerouting of Lake Agassiz overflow through the Great Lakes and St. Lawrence Valley inhibited deep water formation in the subpolar North Atlantic and weakened the strength of the Atlantic Meridional Overturning C...

Condron, Alan; Winsor, Peter

2012-01-01

181

Archean high-Mg monzodiorite-syenite, epidote skarn, and biotite-sericite gold lodes in the Granny Smith-Wallaby district, Australia: U-Pb and Re-Os chronometry of two intrusion-related hydrothermal systems  

Science.gov (United States)

The Granny Smith (37 t Au production) and Wallaby deposits (38 t out of a 180 t Au resource) are located northeast of Kalgoorlie, in 2.7 Ga greenstones of the Eastern Goldfields Province, the youngest orogenic belt of the Yilgarn craton, Western Australia. At Granny Smith, a zoned monzodiorite-granodiorite stock, dated by a concordant titanite-zircon U-Pb age of 2,665 ± 3 Ma, cuts across east-dipping thrust faults. The stock is fractured but not displaced and sets a minimum age for large-scale (1 km) thrust faulting (D2), regional folding (D1), and dynamothermal metamorphism in the mining district. The local gold-pyrite mineralization, controlled by fractured fault zones, is younger than 2,665 ± 3 Ma. In augite-hornblende monzodiorite, alteration progressed from a hematite-stained alkali feldspar-quartz-calcite assemblage and quartz-molybdenite-pyrite veins to a late reduced sericite-dolomite-albite assemblage. Gold-related monazite and xenotime define a U-Pb age of 2,660 ± 5 Ma, and molybdenite from veins a Re-Os isochron age of 2,661 ± 6 Ma, indicating that mineralization took place shortly after the emplacement of the main stock, perhaps coincident with the intrusion of late alkali granite dikes. At Wallaby, a NE-trending swarm of porphyry dikes comprising augite monzonite, monzodiorite, and minor kersantite intrudes folded and thrust-faulted molasse. The conglomerate and the dikes are overprinted by barren (calcite skarn, forming a 600-m-wide and >1,600-m-long replacement pipe, which is intruded by a younger ring dike of syenite porphyry pervasively altered to muscovite + calcite + pyrite. Skarn and syenite are cut by pink biotite-calcite veins, containing magnetite + pyrite and subeconomic gold-silver mineralization (Au/Ag = 0.2). The veins are associated with red biotite-sericite-calcite-albite alteration in adjacent monzonite dikes. Structural relations and the concordant titanite U-Pb age of the skarn constrain intrusion-related mineralization to 2,662 ± 3 Ma. The main-stage gold-pyrite ore (Au/Ag >10) forms hematite-stained sericite-dolomite-albite lodes in stacked D2 reverse faults, which offset skarn, syenite, and the biotite-calcite veins by up to 25 m. The molybdenite Re-Os age (2,661 ± 10 Ma) of the ore suggests a genetic link to intrusive activity but is in apparent conflict with a monazite-xenotime U-Pb age (2,651 ± 6 Ma), which differs from that of the skarn at the 95% confidence level. The time relationships at both gold deposits are inconsistent with orogenic models invoking a principal role for metamorphic fluids released during the main phase of compression in the fold belt. Instead, mineralization is related in space and time to late-orogenic, magnetite-series, high-Mg monzodiorite-syenite intrusions of mantle origin, characterized by Mg/(Mg + FeTOTAL) = 0.31-0.57, high Cr (34-96 ppm), Ni (22-63 ppm), Ba (1,056-2,321 ppm), Sr (1,268-2,457 ppm), Th (15-36 ppm), and rare earth elements (total REE: 343-523 ppm). At Wallaby, shared Ca-K-CO2 metasomatism and Th-REE enrichment (in allanite) link Au-Ag mineralization in biotite-calcite veins to the formation of the giant epidote skarn, implicating a Th + REE-rich syenite pluton at depth as the source of the oxidized hydrothermal fluid. At Granny Smith, lead isotope data and the Rb-Th-U signature of early hematite-bearing wall-rock alteration point to fluid released by the source pluton of the differentiated alkali granite dikes.

Mueller, Andreas G.; Hall, Gregory C.; Nemchin, Alexander A.; Stein, Holly J.; Creaser, Robert A.; Mason, Douglas R.

2008-03-01

182

The geology and geochemistry of mafic and intermediate igneous rocks associated with Cape granites  

International Nuclear Information System (INIS)

Mafic to intermediate rocks, presumably related to the Cape Granite Suite, occur scattered throughout the Western Cape. The major occurrences located near Malmesbury and from Yzerfontein to Mud River on the West Coast were studied in detail using geochemical and isotopic techniques. Smaller outcrops at Philadelphia, Stellenbosch and Kuils River were also sampled and analyzed. The mafic and intermediate rocks are intrusive into tectonized Malmesbury metasediments. The pressure during crystallization of the Malmesbury intrusion is estimated at between 3 and 6 kb using an amphibole geobarometer. An extensive hydrothermal alteration event occured at the West Coast outcrops. This event occured at a pressure of 1.9 to 4.6 kb and a temperature ranging between 462 deg C and 532 deg C as determined by chlorite geothermometry and microthermometry. Most trace elements proved to be mobile during this event, whilst rare earth elements remained stable. Major mineral phases present in the igneous rocks include plagioclase, hornblende, augite, hypersthene and quartz, while alkali feldspar, zircon, sphene, pyrite, and magnetite are present in minor amounts. Minerals formed during the hydrothermal event are epidote, calcite, quartz, pyrite and jasper. Two geochemical trends were distinguished: a calcalkaline trend at Malmesbury and a subalkaline trend along the West Coast including Yzerfontein and Mud River. A monzonitic phase at Yzerfontein yielded a 519 (+ / -7) Ma zircon age. The caelded a 519 (+ / -7) Ma zircon age. The calcalkaline suite is expected to be older. The petrogenesis of this rock suite is complex. Repetitive intrusive events at depth explain much of the variation at Malmesbury and Yzerfontein. Fractional crystallization, remelting, magma mixing and magma mingling all contibuted to the rock-forming processes at Yzerfontein. The mafic and intermediate rocks as well as the Cape granites are interpreted as being intrusive into a subduction zone. This theory is supported by the structure of the Malmesbury metasediment host rock. 105 figs., 13 tabs., 71 refs

183

Rb-Sr age of Gaik granite, Ladakh Batholith, northwest Himalaya  

International Nuclear Information System (INIS)

The Gaik Granite is a part of Ladakh batholith outcropping between Gaik and Kiari in NW Himalaya. This is a pink porphyritic granite rich in biotite and poor in hornblende. Rb-Sr analyses have been made on six whole-rock samples of the Gaik Granite. Though the samples are poorly enriched in radiogenic Sr, they define a reliable isochron corresponding to an age of 235+-13(2sigma) m.y. and initial 87Sr/86Sr ratio of 0.7081+-0.0004 (2sigma), Biotite, plagioclase and potash feldspar fractions separated from two of the samples have yielded a much younger mineral isochron at 30+-1.5 m.y. indicating a nearly complete redistribution of Sr isotopes between mineral phases at a time much later than the primary emplacement of the granite. The present results show that at least some components of the Ladakh batholith are of Permo-Triassic aqe. These rocks were isotopically re-equilibrated on a mineral scale during Upper Oligocene in response to the Himalayan orogeny. (author)

184

P-T path fluid evolution in the Gross Spitzkoppe granite stock, Namibia  

Directory of Open Access Journals (Sweden)

Full Text Available The Gross Spitzkoppe granite stock (GSS is a zoned 30 km^2 epizonal intrusion that consists of three main granites: 1 medium-grained biotite granite (marginal, 2 a coarse-grained biotite granite, and 3 a central, porphyritic granite. The stock contains pegmatites as banded marginal stockscheiders and isolated pockets composed of large alkali feldspar and quartz, dark mica, interstitial fluorite, and euhedral topaz and beryl crystals. In the porphyritic granite there are local wolframite-bearing greisens and hydrothermal fluorite and topaz-rich veins.Fluid inclusion studies were conducted on: 1 topaz and quartz crystals from the marginal stockscheider; 2 quartz, topaz, fluorite and beryl crystals from isolated pegmatites; 3 topaz from a miarolitic pegmatite; 4 beryl and quartz veins from greisenized porphyritic granite; and 5 fluorite from a late fluorite vein inthe coarse-grained biotite granite. Preliminary data indicate the presence of three compositionally distinct primary and pseudosecondary inclusion types that are of late magmatic-hydrothermal origin.Type 1. Low salinity (0–10 eq. wt% NaCl H2O (± CO2 inclusions that homogenize to the liquid phase in the temperature range of 300 to 550?C. These inclusions are from quartz, topaz and beryl. Inclusions in fluorite from the fluorite vein homogenize at ~170?C and have a salinity of ca. 1–2 eq. wt% NaCl.Type 2. Saline (25–30 eq. wt% NaCl halite-bearing H2O (± CO2 inclusions that homogenize to the liquid phase in the temperature range of 300 to 400?C. These inclusions are from quartz.Type 3. Low salinity (0–3 eq. wt% NaCl H2O-CO2 inclusions that homogenize to vapor phase in the temperature range of 330 to 550?C. These inclusions are from quartz and topaz.Hydrothermal fluids from greisen minerals are represented by type 1 and type 2 H2O inclusions. They are predominantly of low salinity (~8 eq. wt% NaCl and homogenize to the liquid phase in the temperature range of 300 to 500?C. Isochores for contemporaneous type 2 and type 3 inclusions with homogenization temperature range of 330 to 400?C indicate a maximum trapping pressure of about 900 bar for the marginal stockscheider.

Stephen Frindt

2002-01-01

185

Lower Carboniferous post-orogenic granites in central-eastern Sierra de Velasco, Sierras Pampeanas, Argentina: U-Pb monazite geochronology, geochemistry and Sr-Nd isotopes  

Science.gov (United States)

The central-eastern part of the Sierra de Velasco (Sierras Pampeanas, NW Argentina) is formed by the large Huaco (40 × 30 km) and Sanagasta (25 × 15 km) granite massifs and the small La Chinchilla stock (2 × 2 km). The larger granites intrude into Ordovician metagranitoids and crosscut Devonian (?) mylonitic shear zones, whereas the small stock sharply intrudes into the Huaco granite. The two voluminous granites are biotitic-muscovitic and biotitic porphyritic syeno- to monzogranites. They contain small and rounded tonalitic and quartz-dioritic mafic microgranular enclaves. The small stock is an equigranular, zinnwaldite- and fluorite-bearing monzogranite. The studied granites are silica-rich (SiO2 >70%), potassium-rich (K2O >4%), ferroan, alkali-calcic to slightly calk-alkalic, and moderately to weakly peraluminous (A/CNK: 1.06-1.18 Huaco granite, 1.01-1.09 Sanagasta granite, 1.05-1.06 La Chinchilla stock). They have moderate to strong enrichments in several LIL (Li, Rb, Cs) and HFS (Nb, Ta, Y, Th, U) elements, and low Sr, Ba and Eu contents. U-Pb monazite age determinations indicate Lower Carboniferous crystallization ages: 350-358 Ma for the Huaco granite, 352.7 ± 1.4 Ma for the Sanagasta granite and 344.5 ± 1.4 Ma for the La Chinchilla stock. The larger granites have similar ?Nd values between -2.1 and -4.3, whereas the younger stock has higher ?Nd of -0.6 to -1.4, roughly comparable to the values obtained for the Carboniferous San Blas granite (-1.4 to -1.7), located in the north of the sierra. The Huaco and Sanagasta granites have a mainly crustal source, but with some participation of a more primitive, possibly mantle-derived, component. The main crustal component can be attributed to Ordovician peraluminous metagranitoids. The La Chinchilla stock derives from a more primitive source, suggesting an increase with time in the participation of the primitive component during magma genesis. The studied granites were generated during a post-orogenic period in a within-plate setting, possibly as a response to the collapse of the previous Famatinian orogen, extension of the crust and mantle upwelling. They are part of the group of Middle Devonian-Lower Carboniferous granites of the Sierras Pampeanas. The distribution and U-Pb ages of these granites suggests a northward arc-parallel migration of this mainly post-orogenic magmatism with time.

Grosse, Pablo; Söllner, Frank; Báez, Miguel A.; Toselli, Alejandro J.; Rossi, Juana N.; de La Rosa, Jesus D.

2009-07-01

186

Network Intrusion Forensic Analysis Using Intrusion Detection System  

OpenAIRE

The need for computer intrusion forensics arises from the alarming increase in the number of computer crimes that are committed annually. After a computer system has been breached and an intrusion has been detected, there is a need for a computer forensics investigation to follow. Computer forensics is used to bring to justice, those responsible for conducting attacks on computer systems throughout the world. Because of this the law must be follow precisely when conducting a forensics investi...

Manish Kumar; Hanumanthappa, Dr M.; Suresh Kumar, Dr T. V.

2011-01-01

187

AMS studies in Portuguese variscan granites  

Science.gov (United States)

A large volume of Variscan granitic rocks outcrop in Central Iberian Zone which are well documented concerning geological mapping, petrography and geochemistry but whose magnetic characteristics and fabric remain unknown. In this study we summarize the available AMS data from approximately 644 sampling stations (5152 samples) on different massifs of Variscan Portuguese granites. Despite their different geological, petrographic and geochemical characteristics, magnetic susceptibility (K) values obtained for the majority of the studied granites range from 15 to 300 × 10-6 SI. The dominant paramagnetic behaviour of the granite bodies reflects the presence of ilmenite as the main iron oxide. This feature indicates the reduced conditions involved in the granite melt formation during the Variscan orogeny. The two-mica granites show K values ranging between 15 to 70 × 10-6 SI which are lower than values displayed by the biotite-rich facies scattered within the interval of 70 and 300 × 10-6 SI. The magnetite-bearing granites are scarce but represented in Lavadores, Gerês and Manteigas. Even so, only the Lavadores body could be considered as a true magnetite-type granite (K >3.0 × 10-3 SI) in face of its K, comprised between 1550 and 19303 × 10-6 SI. Magnetic anisotropy can be used as a "marker" for the deformation experienced by granite mushes during their crustal emplacement and further cooling. Magnetic anisotropy can thus be correlated with the finite deformation of a rock, as record by mineral fabrics. Post-tectonic granites, such as those from Vila Pouca de Aguiar, Pedras Salgadas, Caria, Vila da Ponte, Chaves and Lamas de Olo, have a magnetic anisotropy Porto or Gralheira, the magnetic anisotropy ranges between 5% and 6%, showing high to medium temperature solid-state deformation microstructures (like square-shaped quartz subgrains, recrystallized quartz grains, coupled by kinked biotites and bands of quartz surrounded by mica flakes). In the late to post-tectonic granite bodies, such as those from Castro Daire, Valpaços, Castelo Branco, Mangualde-Trancoso or Serra da Estrela, the magnetic anisotropy falls within the 2.5% and 5% range. The magnetic anisotropy of the Lavadores granite is always higher than 10%. This feature, however, reflects the presence of rough alignments of magnetite co-existent with magmatic to submagmatic microstructures. The shape parameter T is quite variable; however, the average values, for all the massifs, are always higher than zero, suggesting the presence of oblate AMS ellipsoids due to the magnetocrystalline anisotropy of biotite. The values of magnetic susceptibility and magnetic anisotropy allowed a petrophysical characterization of the paramagnetic Variscan granites as was proposed by Sant'Ovaia & Noronha (2005).

Sant'Ovaia, Helena; Martins, Helena; Noronha, Fernando

2014-05-01

188

Intrusion Detection A Machine Learning Approach  

CERN Document Server

This important book introduces the concept of intrusion detection, discusses various approaches for intrusion detection systems (IDS), and presents the architecture and implementation of IDS. It emphasizes on the prediction and learning algorithms for intrusion detection and highlights techniques for intrusion detection of wired computer networks and wireless sensor networks. The performance comparison of various IDS via simulation will also be included.

Tsai, Jeffrey JP

2011-01-01

189

Late-Archaean Potassic Granite from the Bundelkhand Craton, Central India  

Science.gov (United States)

Late-Archaean granitoids, show wide range of compositional variation: (i) TTG like granitoids with strongly fractionated REE patterns, which can be both Na-rich and K-Mg-rich (Sanukitoids) (ii) K-rich, Mg-poor biotite granites with less fractionated REE patterns and showing negative Eu-anomalies (type area, the Closepet Granite, Eastern Dharwar Craton, India). Amongst them Late-Archaean Sanukitoid or K-rich Closepet-type granitoids are most widely reported from the Archaean Cratons world-wide: Superior Province, Canada, Pilbara Craton, Yilgarn Craton, Antarctica, Limpopo Belt, Dharwar Craton. Several models proposed so far for the origin of these granitoids mostly include partial melting of hydrated basalts, reaction of slab melts with mantle wedge peridotites, re-melting of an enriched mantle and then mixing of the resulting melt with the anatectic melt generated during the melting of continental crust in subduction zone settings. The Closepet-type potassic biotite-rich granites were mostly produced by re-melting of TTG-like continental basements most likely in a subduction zone setting. Most of the proposed models suggest such partial melting to have taken place in garnet-stability field and some in orthopyroxene-stability field. In this study we report late-Archaean (~2.61-2.5 Ga) potassic granite from the Bundelkhand Craton in central India. The Late-Archaean granitoids recorded from the craton are intrusive into the high-grade supracrustal rocks of the craton. They are classified as coarse grained grey, pink porphyritic granite, medium granied pink granite, granite porphyry and fine-grained pink granite. The supracrustal rocks of the craton have been metamorphosed at ~2.78 Ga under high-pressure conditions (~17-18 kbar)- medium temperature (600ºC) in a subduction zone setting. The intrusions of the granitoids at ~2.6-2.5 Ga mark the stability of the craton. The pink-porphyritic granite studied here preserves plagioclase-potash feldspar-orthopyroxene-muscovite-biotite-quartz. Plagioclase megacrysts mostly contain orthopyroxene inclusions and are rimmed by anti-perthite and potash feldspar. Biotite and muscovite mostly occur along the potash feldspar grain boundaries or along the grain fractures. The textural observations hence indicate that these granitic rocks are formed in two stages: (i) initial TTG-like melts formed by partial melting of pre-existing mafic supracrustal rocks in the orthopyroxene-stability field, as evidenced by orthopyroxene inclusions in the plagioclase megacrysts, followed by (ii) fractionation of plagioclase crystals, thus making the melt progressively enriched in potassium that led to rimming of the plagioclase megacrysts by anti-perthite or potash feldspar. Biotite and muscovite were formed during later retrogression due to fluid ingression. Whether such magma-forming processes were related to the ~2.78 Ga tectonics recorded from the craton or may be related to a short phase of collision tectonics post to that, needs further investigation.

Sarkar, Saheli; Saha, Lopamudra; Nasipuri, Pritam; Pati, Jayanta Kumar; Patole, Vishal

2014-05-01

190

Thermal expansion of granite rocks  

International Nuclear Information System (INIS)

The thermal expansion of rocks is strongly controlled by the thermal expansion of the minerals. The theoretical thermal expansion of the Stripa Granite is gound to be 21 . 10-6 [deg C]-1 at 25 deg C and 38 . 10-6 [deg C]-1 at 400 deg C. The difference in expansion for the rock forming minerals causes micro cracking at heating. The expansion due to micro cracks is found to be of the same order as the mineral expansion. Most of the micro cracks will close at pressures of the order of 10 - 20 MPa. The thermal expansion of a rock mass including the effect of joints is determined in the pilot heater test in the Stripa Mine

191

Lunar granites with unique ternary feldspars  

Science.gov (United States)

An unusually high concentration of granitic fragments, with textures ranging from holocrystalline to glassy, occurs throughout Boulder 1, a complex breccia of highland rocks from Apollo 17, Station 2. Among the minerals included in the granites are enigmatic K-Ca-rich feldspars that fall in the forbidden region of the ternary diagram. The great variability in chemistry and texture is probably the result of impact degradation and melting of a granitic source-rock. Studies of the breccia matrix suggest that this original granitic source-rock may have contained more pyroxenes and phosphates than most of the present clasts contain. Petrographic observations on Apollo 15 KREEP basalts indicate that granitic liquids may be produced by differentiation without immiscibility, and the association of the granites with KREEP-rich fragments in the boulder suggests that the granites represent a residual liquid from the plutonic fractional crystallization of a KREEP-rich magma. Boulder 1 is unique among Apollo 17 samples in its silica-KREEP-rich composition. We conclude that the boulder represents a source-rock unlike the bedrock of South Massif.

Ryder, G.; Stoeser, D. B.; Marvin, U. B.; Bower, J. F.

1975-01-01

192

Open magma chamber processes in the formation of the Permian Baima mafic-ultramafic layered intrusion, SW China  

Science.gov (United States)

The Baima mafic-ultramafic layered intrusion of the 260-Ma Emeishan Large Igneous Province (ELIP) hosts the second largest Fe-Ti-(V) oxide deposit in the Panxi region, SW China. It is a ~ 1600-m-thick layered body intruded by slightly younger syenitic and granitic plutons. The intrusion includes the Lower and Upper Zones. Troctolite and olivine pyroxenite of the Lower Zone contains conformable oxide ore layers, whereas the Upper Zone consists of olivine gabbro and gabbro with abundant apatite in the higher level. The crystallization order of the silicates in the Baima intrusion is olivine ? plagioclase ? clinopyroxene. Fe-Ti oxides (titanomagnetite and ilmenite) crystallized after olivine, and possibly plagioclase. The oxide ores in the Lower Zone show slightly LREE enriched patterns with (La/Yb)N values between 2.0 and 6.4, and positive Eu anomalies (Eu/Eu*) of 1.0 to 2.7. In contrast, olivine gabbros in the Lower Zone display stronger LREE enrichments (La/YbN = 7.7-14.0) and positive Eu anomalies (Eu/Eu* = 2.8-3.3). Gabbros in the Upper Zone have REE profiles characterized by intermediate LREE enrichments with (La/Yb)N values of 3.2 to 11.2 and positive Eu anomalies of 2.1 to 3.0. Primitive mantle-normalized trace element patterns are characterized by negative La-Ce, Th, Sm and positive Nb-Ta, Ba and Ti anomalies in oxide ores and negative Th-U, Zr-Hf and positive Ba, Sr and Ti anomalies in olivine gabbro and gabbro. Fo of olivine and An of plagioclase remain roughly constant from 0 to ~ 90 m in the Lower Zone, indicating that the magma chamber was continuously filled by compositionally similar magmas during the initial stage. Three magma replenishments occurred afterwards in the upper part of the Lower Zone and the Upper Zone based on compositional reversals of plagioclase, olivine and Sr isotope. Mass balance calculations show that the Baima parental magma can produce all oxide ores under closed system conditions. A wide range of An values of plagioclase within thin sections and disequilibrium Sr isotopic compositions of plagioclase both along the stratigraphic profile (87Sr/86Sri = 0.70312-0.70510) and within thin sections indicate convection and co-accumulation of cumulus plagioclase that had crystallized from different magmas. We propose that the ~ 1600m-thick Baima intrusion formed in an open and isotopically heterogeneous magma chamber that was periodically recharged by compositionally similar or more primitive magmas. In each replenishment cycle, the magma underwent progressive crustal contamination and fractional crystallization. Convection and sorting of crystals based on density differences result in igneous layering characterized by intervals of oxide ores, troctolite and olivine gabbro.

Liu, Ping-Ping; Zhou, Mei-Fu; Wang, Christina Yan; Xing, Chang-Ming; Gao, Jian-Feng

2014-01-01

193

Shrimp U-Pb age and Sr-Nd isotopes of the Morro do Baú mafic intrusion: implications for the evolution of the Arenópolis volcano-sedimentary sequence, Goiás Magmatic Arc  

OpenAIRE

The Arenópolis volcano-sedimentary sequence is located in the southern part of the Goiás Magmatic Arc and includes a ca. 900 Ma calc-alkaline arc sequence made of volcanic rocks ranging in composition from basalts to rhyolites, metamorphosed under greenschist to amphibolite facies. Small calc-alkaline gabbro to granite sub-volcanic bodies are also recognized. The Morro do Baú intrusion is the largest of these intrusions, and is made of gabbros and diorites. Zircon grains separated from one...

Pimentel, Ma?rcio M.; Hollanda, Maria Helena B. M.; Richard Armstrong

2003-01-01

194

Archaean tonalitic-trondhjemitic and granitic plutonism in the Gaviao block, Sao Francisco craton, Bahia, Brazil: geochemical and geochronological characteristics  

International Nuclear Information System (INIS)

The granitic-gneissic terranes of the Gaviao Block in the central-southern Sao Francisco Craton are a Key area to the understanding of the evolution of the South American Platform. The Archaean granitic-gneissic rocks are intimately associated with the Umburanas and Contendas Mirante greenstone belts. The metamorphic grades vary from greenschist to amphibolite facies. These rocks were intensely deformed and intruded by Paleoproterozoic granites. The main evolution of the Gaviao Block is market by the formation of granitoid nuclei during various episodes of TTG plutonism between 3.2 and 3.4 Ga. The TDM Sm-Nd model ages for these granitoids range from 3.2 and 3.6 Ga, indicating involvement of sialic crust in their genesis, in agreement with the ?Nd(t) values between -4.0 and -1.3. Between 3.1 and 2.5 Ga, the Gaviao Block was affected by volcanic and sedimentary activity associated with the formation of the Umburanas and Contendas Mirante greenstone belts, intruded by granites about 2.75 and 2.5 Ga ago. During the paleoproterozoic, the Gaviao Block was regionally deformed and metamorphosed, and intruded by granites between 2.1 and 1.9 Ga. During the mesoproterozoic, tectonic and metamorphic activity occurred between 1.2 and 1.0 Ga as suggested by resetting of Rb-Sr and K-Ar systematics. Finally, regional tectono-thermal overprints in the areas occurred during the Neoproterozoic. These episodes are accompanied by the intrusion of mafic dikes at aboud by the intrusion of mafic dikes at about 0.9 Ga K-Ar ages given by biotites fall within the range 0.5-0.7 Ga and mark the end of the cratonization stage. (author)

195

Granite fracture index to check suitability of granite outcrops for quarrying  

OpenAIRE

the general characterization of the discontinuities of 10 granite rock masses in NE Portugal. During the study some discontinuity characteristics such as orientation, persistence, aperture, trace length and spacing were evaluated. The differences in the characteristics of the selected granites were described, and the most important exploration factors were identified. In the granites studied, most of the joints are oriented from N10°E to N50°E, which is compatible with the regional...

Sousa, L. M. O.

2007-01-01

196

Head and neck malignancies in younger patients  

International Nuclear Information System (INIS)

We treated 23 (1.4% of all our primary cases) younger patients who are from 15 years old to 29 years old with head and neck malignancies at the Department of Head and Neck Surgery of the Miyagi Cancer Center Hospital for the past 12 years. There were 12 male and 11 female, and the sex ratio was approximately 1:1. There were 12 oral cancer patients, 6 epipharyngeal cancer patients and so on. There were 14 squamous cell carcinomas, 3 nasopharyngeal carcinomas and so on. 60% of all cases were squamous cell carcinomas. Clinically, advanced stage (stage III and IV) was diagnosed in 70% of patients at presentation. Although 19 patients had no past history, 2 patients had bronchial asthma, one had schizophrenia, and one had psychological disorder. Radical treatment was performed in 20 of 23 examples. The estimated Kaplan-Meier 5-year cause-specific survival rates for all patients were 76% and the 10-year cause-specific survival rates were 63%, respectively. It was thought that survival consequence was excellent in the whole. The problems of head and neck tumor treatment in a younger patient were thought about with late effect by radioactive rays and genital disorder by cancer chemotherapy. (author)

197

Meltwater routing and the Younger Dryas.  

Science.gov (United States)

The Younger Dryas--the last major cold episode on Earth--is generally considered to have been triggered by a meltwater flood into the North Atlantic. The prevailing hypothesis, proposed by Broecker et al. [1989 Nature 341:318-321] more than two decades ago, suggests that an abrupt rerouting of Lake Agassiz overflow through the Great Lakes and St. Lawrence Valley inhibited deep water formation in the subpolar North Atlantic and weakened the strength of the Atlantic Meridional Overturning Circulation (AMOC). More recently, Tarasov and Peltier [2005 Nature 435:662-665] showed that meltwater could have discharged into the Arctic Ocean via the Mackenzie Valley ~4,000 km northwest of the St. Lawrence outlet. Here we use a sophisticated, high-resolution, ocean sea-ice model to study the delivery of meltwater from the two drainage outlets to the deep water formation regions in the North Atlantic. Unlike the hypothesis of Broecker et al., freshwater from the St. Lawrence Valley advects into the subtropical gyre ~3,000 km south of the North Atlantic deep water formation regions and weakens the AMOC by 30%. We conclude that meltwater discharge from the Arctic, rather than the St. Lawrence Valley, was more likely to have triggered the Younger Dryas cooling. PMID:23129657

Condron, Alan; Winsor, Peter

2012-12-01

198

Determination of dispersity of crushed granite  

International Nuclear Information System (INIS)

The experimental crushed granite column breakthrough curves, using 99Tc as spike tracer and 3H as invariant tracer, are analyzed by different linear regression techniques. Dispersity of crushed granite and retardation factor of 99TcO4- on the crushed granite are determined simultaneously by one linear regression technique. Dispersity of crushed granite is also obtained with 3H as invariant tracer by the other linear regression technique. The dispersities found by spike source and invariant source methods are compared. The experimental results show that the dispersity found by spike source method is close to that found by invariant source method. It indicates that dispersity is only the characteristic of dispersion medium

199

Determination of dispersity of crushed granite  

International Nuclear Information System (INIS)

Experimental crushed granite column breakthrough curves, using 99Tc as spike tracer and 3H as invariant tracer, were analyzed by different linear regression techniques. Dispersity of crushed granite and the retardation factor of 99TcO4- on the crushed granite were determined simultaneously by one linear regression. Dispersity of crushed granite was also obtained with 3H as invariant tracer by the other linear regression. The dispersities found by spike source and invariant source methods are compared. Experimental results show that the dispersity found by the spike source method is close to that found by the invariant source method. This indicates that dispersity is only a characteristic of the dispersion medium. (author)

200

The Maua granitic massif, Central Ribeira Belt, Sao Paulo, Brazil: petrography, geochemistry and U-Pb dating  

Energy Technology Data Exchange (ETDEWEB)

The Maua granitic massif is an elongated body dominated by a porphyritic biotite monzogranite which grades, in its southwestern extremity, to lighter equi granular granite and greisenized (tourmaline)-biotite-muscovite leuco granite. Abundant enclaves can be divided in three types: grey micro granular enclaves, with rounded shapes and igneous textures, are compositionally similar to the enclosing porphyritic granites; dark, rounded, micaceous enclaves have high K/Na, and may correspond to highly assimilated meta sedimentary xenoliths; and angulous gneiss xenoliths seem to be fragments of an unexposed type of country rock. The primitive magmas that formed the massif were Zr, P and LREE-saturated, and became progressively enriched in U, Cs, Y, HREE, F and possibly Ta. Geochemical data show that most of the observed compositional variation can be a reflection of crystal fractionation at the level of emplacement. However, other processes such as magma mixing, contamination and post-magmatic alteration seem to respond for local chemical variations. U-Pb monazite dating point to a crystallization age of 588 {+-} 2 Ma which is ca. 20 myr. younger than those of nearby crust-derived syn-orogenic granites. (author)

Filipov, Marcelo [Sao Paulo Univ., SP (Brazil). Escola Politecnica. Dept. de Engenharia de Minas]. E-mail: filipov@usp.br; Janasi, Valdecir de Assis [Sao Paulo Univ., SP (Brazil). Inst. de Geociencias]. E-mail: vajanasi@usp.br

2001-09-01

201

Precambrian crustal evolution and Cretaceous–Palaeogene faulting in West Greenland: Pre-Nagssugtoqidian crustal evolution in West Greenland: geology, geochemistry and deformation of supracrustal and granitic rocks north-east of Kangaatsiaq  

Directory of Open Access Journals (Sweden)

Full Text Available The area north-east of Kangaatsiaq features polyphase grey orthogneisses, supracrustal rocks and Kangaatsiaq granite exposed within a WSW–ENE-trending synform. The supracrustal rocks are comprised of garnet-bearing metapelites, layered amphibolites and layered, likewise grey biotite paragneisses. Their association and geochemical compositions are consistent with a metamorphosed volcano-sedimentary basin (containing both tholeiitic and calc-alkali lavas and is similar to other Archaean greenstone belts. The Kangaatsiaq granite forms a 15 × 3 km flat, subconcordant body of deformed,pink, porphyritic granite occupying the core of the supracrustal synform, and is demonstrably intrusive into the amphibolites. The granite displays a pronounced linear fabric (L or L > S. Thepost-granite deformation developed under lower amphibolite facies conditions (400 ± 50°C, and is characterised by a regular, NE–SW-trending subhorizontal lineation and an associated irregular foliation, whose poles define a great circle; together they are indicative of highly constrictional strain. The existence of a pre-granite event is attested by early isoclinal folds and a foliation within the amphibolites that is not present in the granite, and by the fact that the granite cuts earlier structures in the supracrustal rocks. This early event, preserved only in quartz-free lithologies, resulted in high-temperature fabrics being developed under upper amphibolite to granulite facies conditions.

Watt, Gordon R.

2006-12-01

202

The Lagoa Real subalkaline granitic complex (south Bahia, Brazil): a source for uranium mineralizations associated with Na-Ca metasomatism  

International Nuclear Information System (INIS)

In the central zone of the Sao Francisco Craton (South Bahia), the lower Proterozoic Lagoa Real granites and orthogneisses overthrust to the West the younger Urandi and Espinhaco metamorphic series, probably a late Brazilian event. This thrust is related to the regional metamorphism (amphibolite facies) of the Lagoa Real granites and induces a reverse HP metamorphism in the over thrusted series. Undeformed granites (sao Timoeto type) present two feldspars, perthitic orthoclase largely predominant over plagioclase (oligoclase ? albite), blue quartz, Fe-rich amphibole and biotite ± clinopyroxene assemblages, ilmenite ? magnetite, zircon, apatite, allanite and Nb ± Ti-REE oxides and silicates. The crystallization of the granites begins at high temperature and under low fO2 and PH2O conditions. Fractional crystallization of pyroxene and plagioclase leads to silica enrichment during magmatic differentiation. Increasing fO2 and PH2O are observed during this evolution. Orthogneisses show strongly recrystallized paragenesis: equal abundance of non-perthitic microcline and plagioclase (oligoclase ? albite), quartz, more Al-rich amphibole and biotite, magnetite, sphene, zircon, allanite, Nb ± Ti-REE oxides and silicates, and ± apatite. HT Na and Ca metasomatism occurs 330 Ma later than granite emplacement and is synchronous with important uranium mineralizations. Major elements and trace-elements geochemistry of the granitesnts geochemistry of the granites and orthogneisses indicate subalkaline to alkaline typology. Incompatible behaviour of Th, REE, Y, Zr, Nb, and F points out a convergence with alkaline magmatism. CI, F, Th, Y, REE, NB enrichments and Ba, Sr depletions are also related to a late magmatic stage. U-Th-rich and metamict accessory minerals of the granites represent a favorabl source for the Lagoa Real uranium ore-deposits

203

INTRUSION DETECTION ON CLOUD APPLICATIONS  

Directory of Open Access Journals (Sweden)

Full Text Available Cloud computing has grown from being a promising business concept to one of the fastestgrowing segments of the IT industry. So, cloud environment always remains vulnerable to attacks. Theframework serves as an excellent platform for making cloud services intrusion tolerant. The feasibility of theframework has been tested by making cloud’s Infrastructure as a Service (IaaS and Data Storage Serviceintrusion tolerant. The proposed framework has been validated by integratingIntrusion Tolerance via Threshold Cryptography (ITTC mechanism in the simulated cloud’s IaaS. For this,the data centre authentication key is distributed among the hosts using Shamir Secret Sharing algorithm.Performance of the new simulated service model is measured using various performance metrics such astotal execution time, intrusion detection time, recovery time, number of cloudlets etc. It involves, usingproposed Cloud Intrusion Tolerance framework for securing cloud Data Storage. The correctness of user’sdata is ensured by using erasure-correcting code in the file distribution preparation to provide redundancyparity vectors. Performance analysis using erasure-correcting code for securing data storage is also done. Weare also implementing the different networks such as SHIM (System Health and Intrusion Monitoring isused as an exemplary host-based IDS to validate our approach, DRCP (Dynamic Registration andConfiguration Protocol is an auto configuration protocol in mobile AdHoc networks, OLSR (Optimized LinkState Routing protocol is a proactive, table-driven routing protocol in MANETs.

A. Venkat Reddy

2013-09-01

204

Monazite-(Ce in Hercynian granites and pegmatites of the Bratislava massif, Western Carpathians: compositional variations and Th-U-Pb electron-microprobe dating  

Directory of Open Access Journals (Sweden)

Full Text Available Monazite-(Ce represents a characteristic magmatic accessory mineral of the Hercynian peraluminous S-type granites to granodiorites and related granitic pegmatites of the Bratislava Granitic Massif (BGM, Malé Karpaty Mountains, Central Western Carpathians, SW Slovakia. Monazite forms euhedral to subhedral crystals, up to 200 ?m in size, usually it is unzoned in BSE, rarely it reveals oscillatory or sector zoning. Thorium concentrations of 2 to 9 wt. % ThO2 (?0.09 apfu and local elevated uranium contents (?4.3 wt. % UO2, ?0.04 apfu are characteristic for the pegmatite monazites. Both huttonite ThSiREE-1P-1 and cheralite Ca(Th,UREE-2 substitutions took place in the studied monazite. Electron-microprobe Th-U-Pb monazite dating of the granites and pegmatites gave an isochron age of 353±2 Ma (MSWD = 0.88, n = 290, which confirmed the meso-Hercynian, Carboniferous, Lower Mississipian magmatic crystallization. An analogous age (359±11 Ma was obtained from monazite from adjacent paragneiss, corresponding to the age of the Hercynian contact thermal metamorphism related to the granite intrusion of BGM. Monazite in some granite shows also older clastic or authigenic grains or zones (~505 to 400 Ma, with maximum of 420±7 Ma which probably represents inherited material from the Lower Paleozoic metapelitic to metapsammitic protolith of BGM.

Pavel Uher

2014-12-01

205

Rn-222 release to the environment: comparison between different granite sources  

International Nuclear Information System (INIS)

In this work three different types of granites were studied, namely: pure granite, alkali granite and altered (hydrated) alkali granite. General radioactivity of the granites was studied along with the potential for 222Rn emanation. The study indicated that altered alkali granite releases, relatively, the highest 222Rn emanation to the surrounding air while alkali granite emits the more intense gamma radiation of the three granites. Hence, altered alkali granite can be used as a laboratory source for 222Rn.

206

Geology, petrology and geochemistry of the Cacapava do Sul Granitic complex, RS  

International Nuclear Information System (INIS)

The Cacapava do Sul Granitic Complex comprises mainly hornblende and biotite-rich granodioritic rocks, leucogranitoids which may contain muscovite and garnet, and transitional types of granitoids. The available data suggest that it is a diapiric intrusion synchronous, with the second regional metamorphism and deformation phase, inprinted on the country rocks and on the batholith itself. Geochemical evidences are consistent with a comagmatic character for the granitic rocks and also indicate calc-alkaline affinity, with an origin either from partial melting of the lower crust or from differentiation of mantle-derived basaltic magmas, with crustal contamination. The geochemical features indicate strong similarities with orogenic granitoids intruded in highly mature arcs. The re-evaluation of Rb-Sr data indicates an age of 549 Ma and initial ratio of 0.7051 for the leucogranites. The available data suggest that the studied complex has been emplaced during the late stages of the Brasiliano Cycle, which were marked by the development of ensialic basins and shear zones, with associated granitic magmatism. In its early stages, this orogeny may be interpreted according to the classical model, involving subduction of oceanic crust. (author)

207

Discordant distribution of U and Pb in zircon of Naegi granite  

International Nuclear Information System (INIS)

The distribution of U, Th and Pb is determined on an electron microprobe for zircon in the Naegi granite of the Late Cretaceous from Hirukawa, Gifu Prefecture, Japan. The UO2, ThO2 and PbO contents of zircon range from less than the detection limit (50 ppm) to 3.45 %, 2.46 % and 360 ppm, respectively. The Pb content of some portions in each grain is equivalent to what has been generated by the radioactive decay of co-existing U and Th since the granite crystallization, but other portions evidently show either deficient or excess Pb with respect to the U and Th contents. The granite has not undergone any thermal event after the intrusion. The Pb-deficiency and -excess are explained in terms of Pb-loss and -gain owing to the migration of gaseous daughters (Rn) through radiation damage. The Rn atoms that entered into a network of radiation damage by recoil at the birth can move at random: they are adsorbed for a moment on the walls of radiation damage, and then re-emitted in random directions. Their residence time on the walls depends on the heat of adsorption which increases with increasing number of irregular sites on the walls, so that Rn atoms tends to decay on irregular walls as compared with smooth walls. This process disturbs the distribution of radiogenic Pb, and brings forth the enrichment and depletion of Pb with respect to the U and Th contents of zircon. (author)

208

Mineralogy, chemistry, and age of granitic veins at Nicholson's Point, South Coast, Natal  

International Nuclear Information System (INIS)

Undeformed granitic veins exposed at Nicholson's Point, southern Natal, intrude nearly all the foliated rock types between Drakes Beach and Leisure Bay and therefore appear to post-date the major deformation episodes. The veins define an en echelon array and appear to have been emplaced syn-tectonically to post-tectonically. In addition to quartz and feldspar, the veins are characterized by variable ferro magnesian minerals, namely, tourmaline, magnetite, dumortierite, and biotite. A Rb/Sr isotope study yields a date of 960 ± 32 Ma which is within error of the date of the nearby deformed Glenmore Granite. These results imply that much of the deformation history recorded in the southern sector of Natal Structural and Metamorphic Province either occurred within a relatively short period or that the age of the Glenmore Granite is a reset age. The veins represent one of the youngest events recognized in the tectonic and intrusive history of the Natal Structural and Metamorphic Province. 18 refs., 7 figs., 5 tabs

209

Is stratospheric air getting younger with time?  

Science.gov (United States)

Most climate models have predicted that with the increase in greenhouse gases concentrations, the stratospheric circulation will intensify, showing younger age-of-air (AoA) values in this region (e.g. Butchart et al., 2010; WMO, 2011). However, balloon and satellite observations do not agree with the widespread modelled trend towards younger age-of-air (Engel et al., 2009; Stiller et al., 2012). To increase our confidence in climate-chemistry projections, the causes for the apparent age-of-air disagreement between observations and most models need to be identified. Here we have carried out stratospheric simulations with a chemistry transport model (CTM) to evaluate the stratospheric circulation with the ERA-Interim dataset produced by the European Centre for Medium-Range Weather Forecasts (ECMWF). The ERA-Interim reanalysis provides age-of-air (AoA) distributions in very good agreement with observations in the lower stratosphere. Given this agreement, we have used our simulations to quantify interannual variability and trends in the stratospheric AoA for the whole ERA-Interim period (1979-present). Our model results with ERA-Interim fields disagree with the decreasing tendency in age-of-air widespread in most models, but are in good agreement with the recent age-of-air studies based on observations. To explore potential causes for the AoA trends in our model, Lagrangian calculations are also performed to assess mixing processes for the ERA-Interim period. Potential links between our modelled AoA trends and stratospheric ozone evolution are also shown. References: Butchart, et al., 2010. J. Climate, 23, 5349-5374, doi:10.1175/2010JCLI3404.1. Engel et al., 2009. Nat. Geosci. 2: 28-31, doi:10.1038/ngeo388. Stiller et al., 2012. Atmos. Chem. Phys. 12: 3311-3331, doi:10.5194/acp-12-3311-2012. WMO. 2011. Global Ozone Research and Monitoring Project -Report No. 52.

Monge-Sanz, Beatriz; Chipperfield, Martyn; Dee, Dick; Simmons, Adrian; Stiller, Gabriele

2014-05-01

210

Corrective nasal surgery in the younger patient.  

Science.gov (United States)

IMPORTANCE To describe clinical parameters for the management of the pediatric patient with nasal anatomical deformity or functional impairment. OBJECTIVES To review the authors' experience with corrective nasal surgery in pediatric patients and make recommendations regarding indications for surgery and surgical techniques. DESIGN, SETTING, AND PARTICIPANTS A retrospective medical chart review was performed for all male patients younger than 16 years and female patients younger than 14 years seen by the senior author (F.G.F.) at a tertiary referral center between August 1996 and August 2012. The database was searched for patients who underwent septoplasty or corrective nasal surgery by the senior author. EXPOSURES Patients included in the study underwent either septoplasty or corrective nasal surgery by the senior author. MAIN OUTCOMES AND MEASURES Age, indication for surgery, surgery performed, and last follow-up appointment was recorded for each patient. In addition, any complications or need for revision surgical or adjunct procedures were noted. RESULTS Demographics and outcomes for 54 pediatric patients were included in the study. The most common indications for surgery were posttraumatic deformities (n = 36) and severe airway obstruction (n = 48). Fifteen patients with severe nasal airway obstruction did not have a documented history of trauma. The mean follow-up period was 646 days (approximately 21 months), with a range of 8 to 4062 days. Five patients underwent a staged procedure, and no patients underwent a revision procedure for unsatisfactory results. CONCLUSIONS AND RELEVANCE Children with nasal obstruction and deformity can safely undergo nasal corrective surgery prior to adolescence. Special considerations include preserving normal structures and the judicious use of grafts. The recommended approaches to managing the pediatric septoplasty and nasal surgery patient are described herein through a series of representative cases. PMID:24503713

Adil, Eelam; Goyal, Neerav; Fedok, Fred G

2014-01-01

211

Correlates of knee pain in younger subjects.  

Science.gov (United States)

The aim of this study was to describe clinical, structural and biochemical factors associated with knee pain in younger subjects. A cross-sectional convenience sample of 371 male and female subjects (mean age, 45 years, range 26-61) was studied. Knee pain was assessed by questionnaire. Chondral defects, cartilage volume, and bone area of the right knee were determined using T1-weighted fat saturation magnetic resonance imaging (MRI). X-ray was performed on the same knee for the assessment of radiographic features of osteoarthritis. The urinary C-terminal cross-linking telopeptide of type II collagen (CTX-II) was measured by enzyme-linked immunosorbent assay (ELISA). Height and weight were measured by standard protocols and body mass index (BMI) was calculated. The prevalence of knee pain was 35% in this sample. Chondral defect scores (particularly femoral and patellar but not tibial) were significantly associated with knee pain in a dose-response fashion (all p<0.01). Cartilage volume and bone area were not associated with knee pain in multivariate analysis in this sample. Urinary CTX-II was higher in subjects with knee pain (p=0.04), but this became nonsignificant after adjustment for BMI and osteophytes (both of which were significant) suggesting potential mechanisms of effect. In conclusion, knee pain is significantly associated with non-full thickness chondral defects (particularly femoral and patellar), osteophytes, CTX-II, and obesity but not other factors. MRI and biochemical measures can add to radiographs in defining unexplained knee pain in younger subjects. PMID:16572288

Zhai, Guangju; Cicuttini, Flavia; Ding, Changhai; Scott, Fiona; Garnero, Patrick; Jones, Graeme

2007-01-01

212

Granites as indicators of uranium provinces  

International Nuclear Information System (INIS)

The origins of U provinces can be attributed to acid magmatic sources with juvenile characteristics which transferred radioelements from the lower to the upper crust and which were formed by partial melting of a F- and LIL-enriched lower crustal-upper mantle source region. The granites were emplaced as dry melts which were further enriched at a high level by fractional crystallization and pervasive metasomatism. The granites and their precursor source regions thus represent a primary and fundamental control on the subsequent development of high level U ore-forming processes. A long period of evolution and enrichment in the lower crust-upper mantle region may thus be required prior to the transferrence of these U enriched magmas from the lower to upper crustal levels and Precambrian crust is often reported from areas where this process is thought to have occurred. Indeed it was emphasized by Bowie (1977) that the occurrence of uranium provinces in Colorado, southern Ontario, South Africa and elsewhere is closely associated with Precambrian crust. Major tectonism and crustal instability during the ore-forming processes are also an essential requirement. On the other hand a model involving the anatexis and high level emplacement of sedimentary rocks in continental collision zones does present many difficulties in accounting for the genesis of U provinces: Firstly, uraniferous granites in orogenic belts are shown to have characteristics similar to those of uraniferous graistics similar to those of uraniferous granites from anorogenic regions and secondly, black shales which have high U contents also have high levels of Co, Cr, Cu, Ni and V; these elements are however notably lacking in the uraniferous granites we have investigated. Studies of mineralized and metalliferous granites from several U provinces show however that it is usually possible to distinguish mineralized from nonmineralized metalliferous granites using selected indicator elements such as F and B. These factors are illustrated by examples ranging from the Archaean to the Phanerozoic from China, South Africa and Europe. 24 refs, 1 fig

213

DOE Intrusion Detection Systems Handbook  

International Nuclear Information System (INIS)

The article reviews the Intrusion Detection Systems Handbook that was prepared by Sandia Laboratories for the U.S. Department of Energy, Office of Safeguards and Security. The purpose of the handbook is to provide information pertinent to the selection, procurement, installation, testing, and maintenance of the elements of an intrusion detection system. These elements include interior and exterior sensors, alarm assessment equipment, and alarm reporting equipment. The handbook also contains a discussion of how these elements can be integrated into an operationally effective system

214

Rare metal granites and related rocks of the Ukrainian shield  

Directory of Open Access Journals (Sweden)

Full Text Available Two rare metal leucocratic granites, Perga and Kamennaya complexes, can be distinquished on the Ukrainian shield. The Perga complex consists of medium- and coarse grained, mainly porphyric, biotite, riebeckite and aegirine granites, granite porphyries, microclinites and albitites with rare metal mineralization (genthelvite, phenacite, tantalite, cassiterite and wolframite etc.. Granites from several stocks (up to 30 km2 in the northwestern part of the shield, situated along the fracture zone, restricted the large Korosten pluton of rapakivi granites to the northwest. The age of these granites (Pb-Pb and U-Pb methods on zircon and monazite practically coincide with the age of rapakivi granites being 1750 Ma. Within the Korosten complex of rapakivi granites we consider that zinnwaldite granites, which are characterized by fluorite and topazine mineralization, represent the final phase of pluton. These granites differ from the Perga ones by their low content of rare metals. The Kamennaya Mogila complex lies in the southeastern part of the Ukrainian shield. It consists of biotite and muscovite-biotite, medium- and coarse-grained (also porphyric, and occasionally greisining granites with rare metal mineralization (cassiterite, columbite, molybdenite, wolframite and beryl. Granites form several stocks (5-30 km2 situated 10-30 km to the west-northwest of the South-Kalchik gabbro-syenite-granite pluton. Granitoids in both of these complexes have similar isotopic ages (1800 Ma. Leucocratic subalkaline granites (the Novoyanisol type are known within the pluton itself, occupying an intermediate position between the above mentioned in terms of mineral and geochemical composition. The gabbro-syenite-granite formation of the Nearazov region has a substantial similarity to the anorthosite-rapakivi-granite formation. In this respect the relation of each of them to rare metal granites is rather remarkable. This relation is, most probably, not only spatial, but also genetic. The typical rare metal granites are situated not in the parent plutons but at some distance from them.

Esipchuk, K.Ye.

1993-12-01

215

Innovative Method for Saltwater Intrusion Control  

OpenAIRE

Salt water intrusion is the migration of saltwater into freshwater aquifers under the influence of groundwater development (Freeze and Cherry, 1979). The most detrimental effect that ground water depletion causes lowering of water table. Another problem due to saltwater intrusion is changing saltwater freshwater interface. Methods for controlling intrusion vary widely depending on the source of the saline water, the extent of intrusion, local geology, water use and economic fa...

Payal, Z.

2014-01-01

216

VISUALIZATION TECHNIQUES FOR INTRUSION DETECTION – A SURVEY  

OpenAIRE

In traditional intrusion detection system (IDS) environments, little activity has been applied to usingvisual analysis as an aid to intrusion detection. With more information systems being attacked and attacktechniques evolving, the task of detecting intrusions is becoming an increasingly difficult. Efficientinformation visualization is an important element required for urgent detection of intruders.This paper presents a survey on using visualization techniques in intrusion detection system.F...

Ibrahim Elhenawy; Alaa El - Din Riad; Ahmed Hassan; Nancy Awadallah

2011-01-01

217

STATISTICAL TECHNIQUES IN ANOMALY INTRUSION DETECTION SYSTEM  

OpenAIRE

In this paper, we analyze an anomaly based intrusion detection system (IDS) for outlier detection in hardware profile using statistical techniques: Chi-square distribution, Gaussian mixture distribution and Principal component analysis. Anomaly detection based methods can detect new intrusions but they suffer from false alarms. Host based Intrusion Detection Systems (HIDSs) use anomaly detection to identify malicious attacks i.e. intrusion. The features are shown by large set of dimensions an...

Hari Om; Tanmoy Hazra

2012-01-01

218

Formation of the Late Permian Panzhihua plutonic-hypabyssal-volcanic igneous complex: Implications for the genesis of Fe-Ti oxide deposits and A-type granites of SW China  

Science.gov (United States)

The Late Permian (260 Ma) Emeishan large igneous province of SW China contains numerous magmatic Fe-Ti oxide deposits. The Fe-Ti oxide deposits occur in the lower parts of evolved layered gabbroic intrusions which are spatially and temporally associated with A-type granitic rocks. The 260 Ma Panzhihua layered gabbroic intrusion hosts one of the largest magmatic Fe-Ti oxide deposits in China and is coeval with a peralkaline A-type granitic pluton. The granite has intruded the overlying Emeishan flood basalts and fed at least one dyke which erupted onto the surface producing columnar jointed trachytes. The presence of syenodiorite between the layered gabbro and granite is evidence for compositional evolution from mafic to intermediate to felsic rocks. The syenodiorites have intermediate to felsic composition with SiO 2 = 61 to 65 wt.%, MgO = 0.27 to 0.6 wt.% and CaO = 1.0 to 2.5 wt.% as compared to the granite SiO 2 = 65 to 72 wt.%, MgO = 0.1 to 0.4 wt.%, CaO = 1(Eu/Eu* = 1.1 to 2.6) in the gabbroic intrusion, to trachytes (Eu/Eu* = 0.55-0.87). Previously published ?Nd (T) values from clinopyroxenes ( ?Nd (T) = + 1.1 to + 3.2) of the gabbroic intrusion match the whole-rock values of the syenodiorite ( ?Nd (T) = + 2.1 to + 2.5), granite and trachyte ( ?Nd (T) = + 2.2 to + 2.9), suggesting that all rock types originated from the same mantle source. MELTS and trace element modeling confirm that all rock types can be generated by fractional crystallization of high-Ti Emeishan basalt. The jump in SiO 2 from the gabbro to the syenodiorite is attributed to the en masse crystallization of the Fe-Ti oxides. The geological and geochemical data indicate that fractional crystallization of a common parental magma produced the layered gabbroic intrusion and Fe-Ti oxide deposit, the syenodiorite, granites and trachyte of the Panzhihua region, which thus form a genetically related plutonic-hypabyssal-volcanic complex. Other granite-gabbro complexes in the region likely formed in a similar manner.

Shellnutt, J. G.; Jahn, B.-M.

2010-01-01

219

Petrochemical and petrophysical changes caused by greisenization in the younger granites of the Krušné hory batholith (Czech Republic).  

Czech Academy of Sciences Publication Activity Database

Rotterdam/Brookfield : A. A. Balkema, 1997 - (Papunen, H.), s. 679-682 ISBN 90 5410 889 4. [Biennal SGA Meeting /4./. Turku (FI), 11.08.1997-13.08.1997] R&D Projects: GA ?R GA205/95/0149 Subject RIV: DB - Geology ; Mineralogy

Štemprok, M.; Chlupá?ová, M.; Pivec, Edvín; Novák, Ji?í Karel; Lang, Miloš

220

Analysis of the Younger Dryas Impact Layer  

Energy Technology Data Exchange (ETDEWEB)

We have uncovered a thin layer of magnetic grains and microspherules, carbon spherules, and glass-like carbon at nine sites across North America, a site in Belgium, and throughout the rims of 16 Carolina Bays. It is consistent with the ejecta layer from an impact event and has been dated to 12.9 ka BP coinciding with the onset of Younger Dryas (YD) cooling and widespread megafaunal extinctions in North America. At many locations the impact layer is directly below a black mat marking the sudden disappearance of the megafauna and Clovis people. The distribution pattern of the Younger Dryas boundary (YDB) ejecta layer is consistent with an impact near the Great Lakes that deposited terrestrial-like ejecta near the impact site and unusual, titanium-rich projectile-like ejecta further away. High water content associated with the ejecta, up to 28 at. percent hydrogen (H), suggests the impact occurred over the Laurentide Ice Sheet. YDB microspherules and magnetic grains are highly enriched in TiO{sub 2}. Magnetic grains from several sites are enriched in iridium (Ir), up to 117 ppb. The TiO{sub 2}/FeO, K/Th, TiO{sub 2}/Zr, Al{sub 2}O{sub 3}/FeO+MgO, CaO/Al{sub 2}O{sub 3}, REE/ chondrite, FeO/MnO ratios and SiO{sub 2}, Na{sub 2}O, K{sub 2}O, Cr{sub 2}O{sub 3}, Ni, Co, U, Th and other trace element abundances are inconsistent with all terrestrial and extraterrestrial (ET) sources except for KREEP, a lunar igneous rock rich in potassium (K), rare-earth elements (REE), phosphorus (P), and other incompatible elements including U and Th. Normal Fe, Ti, and {sup 238}U/{sup 235}U isotopic abundances were found in the magnetic grains, but {sup 234}U was enriched over equilibrium values by 50 percent in Murray Springs and by 130 percent in Belgium. 40K abundance is enriched by up to 100 percent in YDB sediments and Clovis chert artifacts. Highly vesicular carbon spherules containing nanodiamonds, glass-like carbon, charcoal and soot found in large quantities in the YDB layer are consistent with an impact followed by intense burning. Four holes in the Great Lakes, some deeper than Death Valley, are proposed as possible craters produced by the airburst breakup of a loosely aggregated projectile.

Firestone, Richard B.; West, Allen; Revay, Zsolt; Hagstrum, Jonathon T,; Belgya, Thomas; Hee, Shane S. Que; Smith, Alan R.

2010-02-27

221

Locally advanced breast cancer in younger women  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Standard treatment of locally advanced breast cancer is not yet established. In most institutions treatment is multimodal and consists of primary chemotherapy, surgical treatment with or without radiotherapy (RT and hormonal therapy. To find out whether the age influences the kind of surgical treatment in a group of locally advanced breast cancer patients (LABC patients responding to neo-adjuvant chemotherapy. Methods: Analysis included 39 LABC patients treated from January 2000 till January 2003 with neo-adjuvant chemotherapy and surgical treatment in Clinical Center of Montenegro, Podgorica. All patients had locally advanced disease (T2, T3 or T4b and/or N1-2 M1 sc. Patients with T4d tumors were excluded. The treatment consisted of neo-adjuvant chemotherapy, mostly anthracycline based, and surgical treatment - radical mastectomy or breast conserving surgery. Additional procedures after surgical treatment included 3-4 cycles of the same chemotherapy, hormonal treatment and/or RT. Results: Median age of patients was 47 years (range: 24-67 years. Thirty patients were initially in stage IIIA (14 post- and 16 premenopausal patients respectively, 6 patients in stage IIIB (2 post- and 4 premenopausal respectively, and 3 patients in stage IV, with supraclavicular node involvement (M1+sc, 2 post- and 1 premenopausal, respectively. Applied preoperative chemotherapy was anthracycline-based regimen (FAC, 3-6 cycles except in one patient in premenopausal group and 2 patients in postmenopausal group, who had been treated with CMF chemotherapy due to anthracycline contraindications. All analyzed patients responded to neo-adjuvant chemotherapy, mostly with partial or minimal remission of their tumors. In a whole group 15/39 (38% patients had breast conserving surgery (8 pre-, 7 postmenopausal, respectively, 24/39 (61% patients radical mastectomy (13 pre-, 11 postmenopausal, respectively. In a group of patients old 40 years and younger only 2 partial resections were performed (2/9, 22%, and 7 radical mastectomies. Conclusion: Although in a small group of patients, our results confirmed that effective neo-adjuvant chemotherapy enabled breast surgery of LABC, even breast conservative procedure in some patients. However, breast conservation was not possible in majority of young patients. This suggests the investigation of more aggressive neo-adjuvant treatments, especially in patients old 40 years or younger.

Laki?evi? Jadranka

2003-01-01

222

Emotional and Behavioral Reaction to Intrusive Thoughts  

Science.gov (United States)

A self-report measure of the emotional and behavioral reactions to intrusive thoughts was developed. The article presents data that confirm the stability, reliability, and validity of the new seven-item measure. Emotional and behavioral reactions to intrusions emerged as separate factors on the Emotional and Behavioral Reactions to Intrusions

Berry, Lisa-Marie; May, Jon; Andrade, Jackie; Kavanagh, David

2010-01-01

223

Magnetic fabric and modeled strain distribution in the head of a nested granite diapir, the Melechov pluton, Bohemian Massif  

Science.gov (United States)

The Melechov pluton, Bohemian Massif, is interpreted as a mid-crustal nested granitic diapir with an apical part exposed at the present-day erosion level. The diapir head exhibits a concentric structure defined by lithologic zoning and by the anisotropy of magnetic susceptibility (AMS). In concert with theoretical models, outward-dipping margin-parallel magnetic foliations are associated with oblate shapes of the susceptibility ellipsoids and higher degree of anisotropy, passing inward into weaker triaxial to prolate fabric. By contrast, magnetic fabric in an inner granite unit is in places oriented at a high angle to internal contacts and is interpreted as recording an internal diapir circulation. We use inverse modeling to calculate strain variations across the diapir from the AMS data. The magnetic fabric parameters and calculated strains are in agreement with strain distribution in heads of model Newtonian diapirs traveling a distance of two body radii and suggest granitic magma ascent as a crystal-poor suspension followed by crystallization of fabric markers and their response to strain near the final emplacement level. The intrusive fabric thus formed late but, though generally weak, was still capable of recording incremental strain gradient in the granite diapir.

Truba?, Jakub; Žák, Ji?í; Chlupá?ová, Marta; Janoušek, Vojt?ch

2014-09-01

224

Constraints on the timing of granite emplacement, deformation and metamorphism in the Shamva area, Zimbabwe  

Science.gov (United States)

In order to constrain the temporal relationship between granite (sensu lato ) emplacement and metamorphism, isotope work was carried out on the minerals zircon and apatite (U-Pb), garnet (Pb-Pb) and hornblende (Ar-Ar) from wall rock samples in the Shamva area in Zimbabwe. The area, encompassing parts of the Chinamora and Murehwa batholiths and a wedge-shaped greenstone belt segment in between, is commonly quoted in the literature as an example illustrating pluton emplacement processes and deformational models for the Archean. New U-Pb dating of apatite from a boudinaged pegmatite within mafic schists in the batholith-greenstone contact zone has yielded an age of 2619 +28/-24 Ma. This age is interpreted as the best estimation of the intrusion age of this unit, depending on the assumed closure temperature, and provides an upper age limit for the syntectonic emplacement of the now gneissic granites. Pb-Pb dating of late kinematic garnets in cordierite-bearing rocks within the greenstone belt wall rocks gives an age of 2623±8 Ma. Together, this timing of relatively late, syntectonic plutonism and metamorphic mineral growth at ca. 2.62 Ga compares well with existing zircon crystallization ages for felsic volcanics (2645±4 Ma, 2643±8 Ma) and post-tectonic porphyritic monzogranites (2601±14 Ma). Ar-Ar hornblende ages for mafic schists from different areas within the greenstone belt wall rocks range between 2621 and 2498 Ma and have been interpreted to indicate mixing between metamorphic ages and cooling ages. The data support a geological model whereby volcanism and sedimentation are associated with an early phase of regional deformation at ca. 2.64 Ga, which may have started earlier and lasted longer, and evolves into the voluminous emplacement of granites (now gneissic granites) in the batholiths at approximately 2.62 Ga. Emplacement of post-tectonic tabular monzogranites takes place at ca. 2.60 Ga.

Siegesmund, S.; Jelsma, H.; Becker, J.; Davies, G.; Layer, P.; van Dijk, E.; Kater, L.; Vinyu, M.

2002-01-01

225

IGSC perspective on human intrusion  

International Nuclear Information System (INIS)

Hiroyuki Umeki, Chairman of the IGSC, indicated that when updating its programme of work, in 2007, the IGSC raised a number of issues that the group recommended RWMC-RF to consider for further discussion. The conclusions from different IGSC studies were that there is agreement at a conceptual level on the treatment of human intrusion, but a range of approaches are adopted for addressing it in safety assessment, and the degree to which these are specified in regulations also varies considerably among national programmes. The requirements and constraints for considering human intrusion are stylised and, therefore, are largely specified in regulations; in many national programmes, relatively few (or no) aspects are left to the discretion of the implementer. Human intrusion is considered as a sensitive issue for many programmes since it can be an issue of high interest to stakeholders and decisions on approaches are normally undertaken after extensive consultation; those who have already taken decisions are generally satisfied with the outcome and would not welcome work that might undermine or re-open the issue. Thus, a detailed re-examination of safety assessment of human intrusion and of the conclusions that have been reached previously is not a priority. This issue remains of interest to IGSC, however, as it must be addressed in some fashion within all safety cases. The key questions are: - Should regulations require measures to reduce the likelihood or consequences ofo reduce the likelihood or consequences of human intrusion? What 'credit' can be taken for such measures? Is there new thinking or methods in terms of memory and markers? - What types of stylised human intrusion should be considered in a safety case? What are the roles of the regulator and implementer in doing so? - What consequences should be considered? What are the protection criteria against which to assess human intrusion scenarios? - Are the answers to any of these questions site-, culture-, concept- or waste-specific? A concluding question may be: Is there still consensus on the areas of agreement, or has thinking evolved?

226

The GRANIT project: Status and Perspectives  

CERN Document Server

The GRANIT project is the follow-up of the pioneering experiments that first observed the quantum states of neutrons trapped in the earth's gravitational field at the Institute Laue Langevin (ILL). Due to the weakness of the gravitational force, these quantum states exhibit most unusual properties: peV energies and spatial extensions of order 10 $\\mu$m. Whereas the first series of observations aimed at measuring the properties of the wave functions, the GRANIT experiment will induce resonant transitions between states thus accessing to spectroscopic measurements. After a brief reminder of achieved results, the principle and the status of the experiment, presently under commissioning at the ILL, will be given. In the second part, we will discuss the potential of GRANIT to search for new physics, in particular to a modified Newton law in the micrometer range.

ler, Stephan Baeß; Grigorieva, Ludmilla; Kreuz, Michael; Naraghi, Fabrice; Nesvizhevsky, Valery; Pignol, Guillaume; Protassov, Konstantin; Rebreyend, Dominique; Vezzu, Francis; Voronin, Alexei

2012-01-01

227

Retention of Anionic Species on Granite: Influence of Granite Composition - 12129  

International Nuclear Information System (INIS)

Technetium (Tc-99, T1/2 = 2.1.105 yrs) and selenium (Se-79, T1/2 = 6.5.104 yrs) belong among fission products, being produced by fission of nuclear fuel. Both elements can significantly contribute to risk due to their complicated chemistry, long life times, high mobility and prevailing anionic character. Therefore, knowledge of migration behaviour under different conditions can significantly improve input into performance and safety assessment models. Granite is considered as a potential host rock for deep geological disposal of radioactive waste in many countries. Granitic rocks consist usually of quartz, feldspar, plagioclase (main components), mica, chlorite, kaolinite (minor components). The main feature of the rock is advection governed transport in fractures, complemented with diffusion process from fracture towards undisturbed rock matrix. The presented work is focused on interaction of anionic species (TcO4-, SeO42-, SeO32-) with granitic rock. Furthermore, the importance of mineral composition on sorption of anionic species was also studied. The batch sorption experiments were conducted on the crushed granite from Bohemian Massive. Five fractions with defined grain size were used for static batch method. Mineral composition of each granitic fraction was evaluated using X-ray diffraction. The results showed differences in composition of granitic fractions, even though originating from one homogenized material. Sorption experiments showed influence of granite composition on adsorption of both TcO4- and SeO32- on granitic rock. Generally, Se(IV) showed higher retention than Tc(VII). Se(VI) was not almost sorbed at all. Fe containing minerals are pronounced as a selective Se and Tc sorbent, being reduced on their surface. As micas in granite are usually enriched in Fe, increased sorption of anionic species onto mica enriched fractions can be explained by this reason. On the other hand, fractions enriched in feldspar did not show increased sorption affinity to Tc and Se. (authors)

228

Behaviour of three different types of granite under forced alteration  

OpenAIRE

The effect of salt crystallization inside the porous networkof three types of granitic rocks has been studied. Specimen of Grey Granite, Ochre Granite and red/White Granite have been submitted to salt crystallization treatments, following the standard and modified procedures, The decay degree reached is different in each type of stone, according to their petrophysical properties. A surface stone decay is found first when following the standard procedure; the modified procedure leads to a l...

Trujillano, Raquel; In?igo, A. C.; Rives, V.; Vicente Herna?ndez, M. A.

1996-01-01

229

Identification of Granite Varieties from Colour Spectrum Data  

OpenAIRE

The granite processing sector of the northwest of Spain handles many varieties of granite with specific technical and aesthetic properties that command different prices in the natural stone market. Hence, correct granite identification and classification from the outset of processing to the end-product stage optimizes the management and control of stocks of granite slabs and tiles and facilitates the operation of traceability systems. We describe a methodology for automatically identifying gr...

José Antonio Vilán; Javier Martínez; Celestino Ordóñez; María Araújo

2010-01-01

230

The geochemistry of some granite plutons east of Onseepkans  

International Nuclear Information System (INIS)

Characteristic ore minerals are associated with the Daberasgranodiorite, Stolzenfelsenderbite, Narosgranite and Witwatergranite. A detailed petrographic and geochemical investigation of these granites have been conducted. In this study a multi-element approach to granite problems, involving major, minor and selected trace elements has been used to gain insight into the genesis and evolution of the studied granites

231

Zircon geochronology of Berach granite of Chittorgarh, Rajasthan  

International Nuclear Information System (INIS)

Discordant ages of zircons from Berach granite suggest that this granite crystallized around 2610 m.y. ago and lost lead during an episodic event around 710 m.y. The 710 m.y. date probably reflects a response to a regional thermal event also recorded in the 730 m.y. zircon age for the Mt. Abu 'Erinpura type' granite. (author)

232

Accretionary history of the Altai-Mongolian terrane: perspectives from granitic zircon U-Pb and Hf-isotope data  

Science.gov (United States)

The Central Asian Orogenic Belt (CAOB) consists of many tectonic terranes with distinct origin and complicated evolutionary history. Understanding of individual block is crucial to reconstruct the geodynamic history of the gigantic accetionary collage. This study presents zircon U-Pb ages and Hf isotopes for the granitoid rocks in the Russian Altai mountain range (including Gorny Altai, Altai-Mongolian terrane and CTUS suture zone between them), in order to clarify the timing of granitic magmatism, source nature, continental crustal growth and tectonic evolution. Our dating results suggest that granitic magmatism of the Russian Altai mountain range occurred in three major episodes including 445~429 Ma, 410~360 Ma and ~241 Ma. Most of the zircons within the Paleozoic granitoids present comparable positive ?Hf(t) values and Neoproterozoic crustal model ages, which favor the interpretation that the juvenile crustal materials produced in the early stage of CAOB were probably dominant sources for the Paleozoic magmatism in the region. The inference is also supported by widespread occurrence of short-lived juvenile materials including ophiolites, seamount relics and arc assemblages in the north CAOB. Consequently, the Paleozoic massive granitic rocks maybe not represent continental crustal growth at the time when they were emplaced, but rather record reworking of relatively juvenile Proterozoic crustal rocks although mantle-derived mafic magma was possibly involved to sever as heat engine during granitic magma generation. The Early Triassic granitic intrusion may be product in an intra-plate environment, as the case of same type rocks in the adjacent areas. The positive ?Hf(t) values (1.81~7.47) and corresponding Hf model ages (0.80~1.16 Ga) together with evidence of petrology are consistent with the interpretation that the parental magma of the Triassic granitic intrusion was produced from enriched mantle-derived sources under an usually high temperature condition which is likely due to basaltic magma that underplated the lower crust. Our data combined with evidence of the regional geology enable us to conclude that the Gorny Altai and Altai-Mongolian terranes possibly have similar tectonic natures, but represent two separate accretionary systems before Devonian collision. The accretion and amalgamation processes resulted in the Paleozoic granitoid magmatism and caused the two terranes to merge as a composite tectonic domain at the Siberian continental margin.

Cai, Keda; Sun, Min; Xiao, Wenjiao

2014-05-01

233

Petrology, geochemistry and origin of topaz granite.  

Czech Academy of Sciences Publication Activity Database

New York : Nova Science, 2012 - (Blasik, M.; Hanika, B.), s. 99-115 ISBN 9781620815663 R&D Projects: GA ?R GA205/09/0540 Institutional research plan: CEZ:AV0Z30460519 Keywords : topaz granite * mineralogy * geochemistry Subject RIV: DB - Geology ; Mineralogy

René, Miloš

234

Scaling property of ideal granitic sequences  

Directory of Open Access Journals (Sweden)

Full Text Available Quantification of granite textures and structures using a mathematical model for characterization of granites has been a long-term attempt of mathematical geologists over the past four decades. It is usually difficult to determine the influence of magma properties on mineral crystallization forming fined-grained granites due to its irregular and fine-grained textures. The ideal granite model was originally developed for modeling mineral sequences from first and second-order Markov properties. This paper proposes a new model for quantifying scale invariance properties of mineral clusters and voids observed within mineral sequences. Sequences of the minerals plagioclase, quartz and orthoclase observed under the microscope for 104 aplite samples collected from the Meech Lake area, Gatineau Park, Québec were used for validation of the model. The results show that the multi-scale approaches proposed in this paper may enable quantification of the nature of the randomness of mineral grain distributions. This, in turn, may be related to original properties of the magma.

D. Xu

2007-06-01

235

Ilmenit z dvojslídných granit? klenovského plutonu.  

Czech Academy of Sciences Publication Activity Database

Ro?. 46, Prosinec (2013), s. 224-227. ISSN 0514-8057 R&D Projects: GA MŠk ME10083 Institutional support: RVO:67985891 Keywords : ilmenite * two-mica granite * Moldanubian Zone * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy http://www.geology.cz/zpravy/obsah/2012/Zpravy_2012-45.pdf

René, Miloš

2013-01-01

236

The role of xenoliths and flow segregation in the genesis and evolution of the Paleoproterozoic Itapema Granite, a crustally derived magma of shoshonitic affinity from southern Brazil  

Science.gov (United States)

The Paleoproterozoic Itapema Granite (IG) is a large granitic body that intrudes orthogneisses and amphibolites, altogether representing part of the basement for Neoproterozoic granitic magmatism in southern Brazil. It is composed of fine- to medium-grained hornblende-biotite monzogranites to granodiorites that host abundant country-rock xenoliths and irregularly distributed mafic aggregates. Interaction between magmatic flow and low flow-velocity zones related to xenolith-rich portions resulted in flow segregation and mineral fractionation as the main mechanisms that led to compositional and textural diversity, expressed also in geochemical trends. The geometry and distribution of flow foliation suggest that the Itapema Granite is a subhorizontal, sheet-like intrusion and that its emplacement was controlled by thrusting under upper-amphibolite facies conditions. Many geochemical characteristics of the Itapema Granite are similar to those of shoshonitic granitoids. However, lower alkali contents, lack of basic or intermediate associated rocks and intimate temporal association with high-grade gneisses and migmatites suggest that it was crustally derived. Its origin is compatible with melting of amphibolitic orthogneisses derived from continental tholeiitic or shoshonitic sequences under high geothermal gradient conditions, where temperatures reached at least 850 °C.

Bitencourt, M. F.; Nardi, L. V. S.

237

Cognitive Control and Lexical Access in Younger and Older Bilinguals  

Science.gov (United States)

Ninety-six participants, who were younger (20 years) or older (68 years) adults and either monolingual or bilingual, completed tasks assessing working memory, lexical retrieval, and executive control. Younger participants performed most of the tasks better than older participants, confirming the effect of aging on these processes. The effect of…

Bialystok, Ellen; Craik, Fergus; Luk, Gigi

2008-01-01

238

Differences in Psychologists' Ratings of Older and Younger Clients.  

Science.gov (United States)

Presented 192 clinical psychologists with clinical vignettes in which client ages varied. Respondents rated older depressed and older agoraphobic clients as significantly less ideal than younger clients with identical symptoms and histories. Older depressed and manic clients also were given significantly poorer prognoses than younger clients.…

Ray, Diane C.; And Others

1987-01-01

239

Shrimp U-Pb age and Sr-Nd isotopes of the Morro do Baú mafic intrusion: implications for the evolution of the Arenópolis volcano-sedimentary sequence, Goiás Magmatic Arc  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese A seqüência vulcano-sedimentar de Arenópolis, localizada na porção sul do Arco Magmárico de Goiás, inclui uma associação de rochas vulcânicas calci-alcalinas de arco com ca. 900 Ma de idade, constituída de rochas variando em composição entre basaltos e riolitos, metamorfisados em fácies xisto verde [...] a anfibolito. Pequenos corpos sub-vulcânicos de gabros a granitos calci-alcalinos são também reconhecidos. A intrusão do Morro do Baú é a maior dessas intrusões, compreendendo dioritos e gabros. Cristais de zircão separados de uma amostra de gabro e analisados no SHRIMP I indicaram a idade 206Pb/238U média de 890 +/- 8 Ma, mostrando que a intrusão é grosseiramente contemporânea, ou talvez um pouco mais jovem que as rochas vulcânicas. Ao contrário das rochas metavulcânicas, que são juvenis, a composição isotópica de Nd do gabro do Morro do Baú indica forte contaminação com material siálico arqueano (T DM de 2.8 Ga e EpsilonNd(T) igual a -9.7), representado na área por uma pequena fatia tectônica de rocha gnáissica arqueana/paleoproterozóica (gnaisse Ribeirão), e que representa a rocha encaixante da intrusão gabro-diorítica. A idade de cristalização de ca. 890 Ma representa, portanto, um limite mínimo para a acresção tectônica do gnaisse Ribeirão às rochas mais jovens da seqüência de Arenópolis. Os dados sugerem que esse evento foi precoce na evolução da seqüência vulcano-sedimentar de Arenópolis, provavelmente entre ca. 920 e 890 Ma. Abstract in english The Arenópolis volcano-sedimentary sequence is located in the southern part of the Goiás Magmatic Arc and includes a ca. 900 Ma calc-alkaline arc sequence made of volcanic rocks ranging in composition from basalts to rhyolites, metamorphosed under greenschist to amphibolite facies. Small calc-alkali [...] ne gabbro to granite sub-volcanic bodies are also recognized. The Morro do Baú intrusion is the largest of these intrusions, and is made of gabbros and diorites. Zircon grains separated from one gabbro sample and analyzed by SHRIMP I yielded the mean 206Pb/238U age of 890 +/- 8 Ma, indicating that the intrusion is roughly coeval or only slightly younger than the Arenópolis volcanics. Contrary to the metavolcanics, which are juvenile, the Nd isotopic composition of the Morro do Baú gabbro indicates strong contamination with archean sialic material (T DM of 2.8 Ga and EpsilonNd(T) of -9.7), represented in the area by an allochthonous sliver of archean/paleoproterozoic gneisses (Ribeirão gneiss) which are the country-rocks for the gabbro/dioritic intrusion. The emplacement age of ca. 890 Ma represents a minimum age limit for the tectonic accretion of the gneiss sliver to the younger rocks of the Arenópolis sequence. The data suggest that this happened early in the evolution of the Goiás Magmatic Arc, between ca. 920 and 890 Ma.

Márcio M., Pimentel; Maria Helena B. M., Hollanda; Richard, Armstrong.

2003-09-01

240

Geochemical evolution of magmatism in Archean granite-greenstone terrains  

Science.gov (United States)

Evolution of Archean magmatism is one of the key problems concerning the early formation stages of the Earth crust and biosphere, because that evolution exactly controlled variable concentrations of chemical elements in the World Ocean, which are important for metabolism. Geochemical evolution of magmatism between 3.5 and 2.7 Ga is considered based on database characterizing volcanic and intrusive rock complexes of granite-greenstone terrains (GGT) studied most comprehensively in the Karelian (2.9-2.7 Ga) and Kaapvaal (3.5-2.9 Ga) cratons and in the Pilbara block (3.5-2.9 Ga). Trends of magmatic geochemical evolution in the mentioned GGTs were similar in general. At the early stage of their development, tholeiitic magmas were considerably enriched in chalcophile and siderophile elements Fe2O3, MgO, Cr, Ni, Co, V, Cu, and Zn. At the next stage, calc-alkaline volcanics of greenstone belts and syntectonic TTG granitoids were enriched in lithophile elements Rb, Cs, Ba, Th, U, Pb, Nb, La, Sr, Be and others. Elevated concentrations of both the “crustal” and “mantle-derived” elements represented a distinctive feature of predominantly intrusive rocks of granitoid composition, which were characteristic of the terminal stage of continental crust formation in the GGTs, because older silicic rocks and lithospheric mantle were jointly involved into processes of magma generation. On the other hand, the GGTs different in age reveal specific trends in geochemical evolution of rock associations close in composition and geological position. First, the geochemical cycle of GGT evolution was of a longer duration in the Paleoarchean than in the Meso-and Neoarchean. Second, the Paleoarche an tholeiitic associations had higher concentrations of LREE and HFSE (Zr, Ti, Th, Nb, Ta, Hf) than their Meso-and Neoarchean counterparts. Third, the Y and Yb concentrations in Paleoarchean calc-alkaline rock associations are systematically higher than in Neoarchean rocks of the same type, while their La/Yb ratios are in contrast lower than in the latter. These distinctions are likely caused by evolution of mantle magmatic reservoirs and by changes in formation mechanisms of silicic volcanics and TTG granitoids. The first of these factors was likely responsible for appearance of sanukitoid magmatic rocks in the Late Mesoarchean. Representative database considered in the work includes ca. 500 precision analyses of Archean magmatic rocks.

Samsonov, A. V.; Larionova, Yu. O.

2006-05-01

241

Treatment of younger patients with chronic lymphocytic leukemia.  

Science.gov (United States)

Younger patients (defined as patients younger than 50-55 years of age) represent a small group of newly diagnosed patients with chronic lymphocytic leukemia, accounting only for 10% to 20% of newly diagnosed cases. However, once these patients become symptomatic and require treatment, their life expectancy is significantly reduced. Therapeutic approaches for younger patients should be directed at improving survival by achieving a complete remission and, where possible, eradicating minimal residual disease. Chemoimmunotherapy combinations carry the highest response rates and are commonly offered to younger patients. Additional strategies that should be considered for younger patients include early referral for stem-cell transplantation and clinical trials of consolidation therapy to eliminate minimal residual disease. PMID:21239775

Ferrajoli, Alessandra

2010-01-01

242

Archaean tonalitic-trondhjemitic and granitic plutonism in the Gaviao block, Sao Francisco craton, Bahia, Brazil: geochemical and geochronological characteristics  

Energy Technology Data Exchange (ETDEWEB)

The granitic-gneissic terranes of the Gaviao Block in the central-southern Sao Francisco Craton are a Key area to the understanding of the evolution of the South American Platform. The Archaean granitic-gneissic rocks are intimately associated with the Umburanas and Contendas Mirante greenstone belts. The metamorphic grades vary from greenschist to amphibolite facies. These rocks were intensely deformed and intruded by Paleoproterozoic granites. The main evolution of the Gaviao Block is market by the formation of granitoid nuclei during various episodes of TTG plutonism between 3.2 and 3.4 Ga. The T{sub DM} Sm-Nd model ages for these granitoids range from 3.2 and 3.6 Ga, indicating involvement of sialic crust in their genesis, in agreement with the {epsilon}N{sub d}(t) values between -4.0 and -1.3. Between 3.1 and 2.5 Ga, the Gaviao Block was affected by volcanic and sedimentary activity associated with the formation of the Umburanas and Contendas Mirante greenstone belts, intruded by granites about 2.75 and 2.5 Ga ago. During the paleoproterozoic, the Gaviao Block was regionally deformed and metamorphosed, and intruded by granites between 2.1 and 1.9 Ga. During the mesoproterozoic, tectonic and metamorphic activity occurred between 1.2 and 1.0 Ga as suggested by resetting of Rb-Sr and K-Ar systematics. Finally, regional tectono-thermal overprints in the areas occurred during the Neoproterozoic. These episodes are accompanied by the intrusion of mafic dikes at about 0.9 Ga K-Ar ages given by biotites fall within the range 0.5-0.7 Ga and mark the end of the cratonization stage. (author) 53 refs., 9 figs., 7 tab.

Leal, Luiz Rogerio Bastos; Teixeira, Wilson [Sao Paulo Univ., SP (Brazil). Inst. de Geociencias; Cunha, Jose Carlos [Companhia Bahiana de Pesquisa Mineral, Salvador, BA (Brazil); Macambira, Moacir Jose Buenano [Para Univ., Belem, PA (Brazil). Lab. de Geologia Isotopica

1998-06-01

243

Nature and origin of Proterozoic A-type granitic magmatism in the southwestern United States of America  

Science.gov (United States)

The mountain ranges of Arizona and adjacent California and Nevada contain large areas underlain by Proterozoic anorogenic granites comprising the southwesternmost portion of a transcontinental belt of 1.4-1.5-Ga-old anorogenic complexes that extends across North America northeast into Labrador. Of these, a two-mica, monazite-bearing granitic suite resides in central and southeastern Arizona as part of a peraluminous subprovince that is bordered on the south (southern Arizona to Sonora) and west (western Arizona and adjacent portions of California and Nevada) by marginally metaluminous granites bearing biotite-sphene ± hornblende and fluorite. All of these 1.4-Ga granites are distinctly more potassic, iron-enriched (relative to Mg), and depleted in Ca, Mg and Sr in contrast to typical orogenic granitoids. In general, the large-ion lithophile-element enriched composition is a consequence of limited melting of a water-deficient crustal source at depths greater than 25-37 km. For the peraluminous granites, this contrast is less extreme, perhaps resulting from a larger degree of melting as a consequence of a greater metasedimentary component and water in its crustal source. The anorogenic granitic magmas intruded into the upper crust at depths of 8-17 km or shallower at temperatures up to 790°C. The most dramatic variation in the crystallization-intensive parameters resides in the oxygen fugacity, which spans three orders of magnitude. Relative to other anorogenic suites, all of the magmas crystallized at elevated levels of ƒ O 2 as reflected in their assignment to the anorogenic magnetite series. Yet a regionally significant rise in primary ƒ O 2 levels, unmatched elsewhere in the transcontinental belt, occurs for plutons in western Arizona, including the Holy Moses and Hualapai granites. The most extreme case is the Hualapai granite whose biotite {Fe}/{( Fe + Mg)} ratios drop (due to high ƒ O 2) to a low of 0.27, down from more typical levels of 0.54 to 0.75. Such extreme variations in primary levels of oxygen fugacity must be an indirect imprint of regional changes of the level of oxidation of the lower crust. The high-f O 2 Holy Moses and Hualapai plutons have intruded near the regional boundary between the metaluminous and peraluminous granites and appear to be imaging a major change in the level of oxidation of the lower crust. This boundary is also approximately equivalent to significant changes in the Nd and Pb isotopic compositions of these granites and the metamorphic and magmatic character of the older orogenic terrane. On a global scale, the crust-forming orogenies ended by 1.6 Ga ago and the continents entered a long-lived era dominated by localized extension and transcontinental intrusion of anorogenic potassic rapakivi granite, mafic dike swarms, charnockite and anorthosite. The absence of orogenic deformation implies that plate consumption became intraoceanic during this time. The profuse and widespread nature of the igneous activity has no Phanerozoic analogue and is considered to be unique to the Proterozoic. A crustal overturn model ties the magmatism to heating within a largely undepleted subcontinental mantle, the eventual rise of mantle plumes, and the transfer of heat into the youthful, undifferentiated Proterozoic crust. Subsequent melting and rise of potassic granitic magmas from the lower crust leads to considerable crustal reorganization, a process that would continue until both the mantle and crust reached a stable configuration.

Anderson, J. Lawford; Bender, E. Erik

1989-06-01

244

2005 dossier: granite. Tome: phenomenological evolution of the geologic disposal  

International Nuclear Information System (INIS)

This document makes a status of the researches carried out by the French national agency of radioactive wastes (ANDRA) about the phenomenological aspects of the geologic disposal of high-level and long-lived radioactive wastes (HLLL) in granite formations. Content: 1 - introduction: ANDRA's research program on disposal in granitic formation; 2 - the granitic environment: geologic history, French granites; 3 - HLLL wastes and disposal design concepts; 4 - identification, characterization and modeling of a granitic site: approach, geologic modeling, hydrologic and hydro-geochemical modeling, geomechanical and thermal modeling, long-term geologic evolution of a site; 5 - phenomenological evolution of a disposal: main aspects of the evolution of a repository with time, disposal infrastructures, B-type wastes disposal area, C-type wastes disposal area; spent fuels disposal area, radionuclides transfer and retention in the granitic environment; 6 - conclusions: available knowledge, methods and tools for the understanding and modeling of the phenomenological evolution of a granitic disposal site. (J.S.)

245

Classification and Importance of Intrusion Detection System  

Directory of Open Access Journals (Sweden)

Full Text Available An intrusion detection system (IDS is a device or software application that monitors network or system activities for malicious activities or policy violations and produces reports to a Management Station. Some systems may attempt to stop an intrusion attempt but this is neither required nor expected of a monitoring system. Due to a growing number of intrusion events and also because the Internet and local networks have become so ubiquitous, organizations are increasingly implementing various systems that monitor IT security breaches. This includes an overview of the classification of intrusion detection systems and introduces the reader to some fundamental concepts of IDS methodology: audit trail analysis and on-the-fly processing as well as anomaly detection and signature detection approaches. This research paper discusses the primary intrusion detection techniques and the classification of intrusion Detection system.

Rajasekaran K

2012-08-01

246

Distributed Approach of Intrusion Detection System: Survey  

OpenAIRE

Intrusion Detection Systems (IDS) are now becoming one of burning issue for any organization’s network. Intruders always search for vulnerabilities or flaws in target system and attack using different techniques. An intrusion detection system (IDS) is needed to detect and respond effectively whenever the confidentiality, integrity, and availability of computer resources are under attack. Today, number of open sources and commercial Intrusion Detection Systems are available to match organi...

Vineet Richariya, Uday Pratap Singh

2012-01-01

247

Classification and Importance of Intrusion Detection System  

OpenAIRE

An intrusion detection system (IDS) is a device or software application that monitors network or system activities for malicious activities or policy violations and produces reports to a Management Station. Some systems may attempt to stop an intrusion attempt but this is neither required nor expected of a monitoring system. Due to a growing number of intrusion events and also because the Internet and local networks have become so ubiquitous, organizations are increasingly implementing variou...

Rajasekaran K; Nirmala K

2012-01-01

248

Intrusion scenarios in fusion waste disposal sites  

Energy Technology Data Exchange (ETDEWEB)

Results of analyses on human intrusions into repositories of fusion radioactive waste are presented. The main topics are: duration of the institutional control, occurrence of intrusion, intrusion scenarios, acceptable risk limits and probabilistic data. Application to fusion waste repositories is implemented with a computational model: wells drilling is considered as the possible scenario. Doses and risks to intruder for different SEAFP-2 cases turn out to be very small. No intervention to reduce the hazard is necessary. (authors)

Zucchetti, M. [European Commission, JRC, Institute for Advanced Material, Ispra, Vatican City State, Holy See (Italy); Zucchetti, M.; Rocco, P. [Energetics Dept., Polytechnic of Turin (Italy)

1998-07-01

249

Network Intrusion Detection Types and Computation  

OpenAIRE

Our research created a network Intrusion Detection Math (ID Math) consisting of two components: (1) a way of specifying intrusion detection types in a manner which is more suitable for an analytical environment; and (2) a computational model which describes methodology for preparing intrusion detection data stepwise from network packets to data structures in a way which is appropriate for sophisticated analytical methods such as statistics, data mining, and computational intelligence. We used...

Purvag Patel; Chet Langin; Feng Yu; Shahram Rahimi

2012-01-01

250

Self-adaptive web intrusion detection system  

OpenAIRE

The evolution of the web server contents and the emergence of new kinds of intrusions make necessary the adaptation of the intrusion detection systems (IDS). Nowadays, the adaptation of the IDS requires manual -- tedious and unreactive -- actions from system administrators. In this paper, we present a self-adaptive intrusion detection system which relies on a set of local model-based diagnosers. The redundancy of diagnoses is exploited, online, by a meta-diagnoser to check t...

Guyet, Thomas; Quiniou, Rene?; Wang, Wei; Cordier, Marie-odile

2009-01-01

251

Hybrid Multi-level Intrusion Detection System  

OpenAIRE

Intrusion detection is a critical process in network security. Nowadays new intelligent techniques have been used to improve the intrusion detection process. This paper proposes a hybrid intelligent intrusion detection system to improve the detection rate for known and unknown attacks. We examined different neural network & decision tree techniques. The proposed model consists of multi-level based on hybrid neural network and decision tree. Each level is implemented with the technique which g...

Sahar Selim; Mohamed Hashem; Nazmy, Taymoor M.

2011-01-01

252

Intrusion Detection Using Data Mining Technique  

OpenAIRE

In reality it is not possible to prevent security breaches completely using the existing security technologies. The intrusion detection plays an important role in network security and information system. However, many current intrusion detection systems (IDSs) are signature based systems. The signature based IDS also known as misuse detection looks for a specific signature to match, and identify an intrusion. When the signatures or patterns are provided, they can detect all known attack patte...

Stuti Singh; Roshan Srivastava

2013-01-01

253

Schizotypy: a vulnerability factor for traumatic intrusions.  

OpenAIRE

Intrusive mental experiences occur within posttraumatic stress disorder (PTSD) and some psychotic disorders. Similarities in the phenomenology and content in the intrusions of both disorders have been noted. Currently there is little understanding of any common etiology in terms of information-processing styles. This study investigated predictors of analogue posttraumatic intrusive cognitions within a nonclinical sample, including schizotypy, dissociation, and trauma history. Forty-two partic...

Holmes, Ea; Steel, C.

2004-01-01

254

Intrusion Preventing System using Intrusion Detection System Decision Tree Data Mining  

OpenAIRE

Problem statement: To distinguish the activities of the network traffic that the intrusion and normal is very difficult and to need much time consuming. An analyst must review all the data that large and wide to find the sequence of intrusion on the network connection. Therefore, it needs a way that can detect network intrusion to reflect the current network traffics. Approach: In this study, a novel method to find intrusion characteristic for IDS using decision tree machine learning of data ...

Syurahbil; Noraziah Ahmad; Zolkipli, M. F.; Abdalla, Ahmed N.

2009-01-01

255

Interaction between magmatic and tectonic stresses during dyke intrusion Interacción entre esfuerzos magmáticos y tectónicos durante la intrusión de diques  

OpenAIRE

Cataclastic and mylonitic rocks exposed in the southwestern part of the Peninsula de Mejillones, northern Chile, are intruded at high angles of the foliation by younger, steeply inclined (±70°) basaltic dykes that resemble intrusive tension gashes with knife-edge contacts with the country rocks. These late dykes developed sigmoidaly-shaped, preferred orientation paths defined by oriented pyroxene phenocrysts that vary in size, aspect ratio, concentration and distribution across the width of...

Jorge Skarmeta

2011-01-01

256

The Pedregal granite (Portugal: petrographic and geochemical characterization of a peculiar granitoid  

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Full Text Available The Pedregal granite outcrops in the Central Iberian Zone, northern Portugal, in the eastern border of a synorogenic variscan granite-migmatite complex sub-concordant with the regional metamorphic structures. It is a granitoid (ca. 3 km2 with an elongated NW-SE shape intruded in staurolite-micaschist and banded gneiss-migmatite rocks, with local igneous breccias in the contact. The country rocks belong to a metapelitic and metasammitic sequence of Edicarian-Cambrian age, known as the “Complexo Xisto-Grauváquico” (CXG which shows a main regional foliation with a NW-SE to NNW-SSE direction. The Pedregal granite is peraluminous (its A/CNK parameter ranges from 1.18 to 1.62, with a magnesian and alkali to alkali-calcic signature. The peculiar features of the granite are high contents of Zr (389 to 435 ppm and a LREE flat pattern, which are uncommon characteristics for granitic rocks, as well as the corroded shape of the biotite, and the large amount of secondary muscovite. These peculiar features distinguish it from the adjacent synorogenic granites. The field, petrographical and chemical features of the Pedregal granite are in accordance with a second phase of partial melting of a residuum, depleted by melt segregation during a first melting episode with the involvement of peritectic garnet and abundant residual biotite with LREE- and Zr-bearing accessory minerals. Besides, the intrusive character of the granite, and the presence of metasedimentary xenoliths point out to a secondary diatexite.El granito de Pedregal aflora en la Zona Centro-Ibérica, en el norte de Portugal, en el borde oriental de un complejo granito-migmatítico sinorogénico varisco, subconcordante con las estructuras metamórficas regionales. Es un granitoide (ca. 3 km2 de forma elongada NW-SE, que intruye en micaesquistos estaurolíticos y en rocas gneissico- migmatíticas bandeadas, con brechas ígneas locales en el contacto. Las rocas encajantes pertenecen a una secuencia metapelítica-metasamítica de edad Ediacariense - Cámbrico, conocida como el “Complejo Esquisto-Grauváquico” (CEG, que muestra una foliación regional principal NW-SE a NNW- SSE. El granito de Pedregal es peralumínico (el parámetro A/CNK oscila desde 1.18 hasta 1.62, con una composición magnesiana, entre alcalina y alcalino-cálcica. Sus características peculiares son el alto contenido de Zr (389–435 ppm y de tierras raras ligeras (LREE que presentan un patrón plano, la forma corroída de la biotita, y la gran cantidad de moscovita secundaria. Estas características peculiares lo distinguen de los otros granitos sinorogénicos adyacentes. Las características de campo, petrográficas y químicas del granito de Pedregal parecen apuntar a una segunda fase de fusión parcial de un residuo, empobrecido por la segregación de fundido durante una primera fase de fusión con participación de granate peritéctico y abundante biotita residual con minerales accesorios portadores de LREE y Zr. Además, el carácter intrusivo del granito, y la presencia de xenolitos metasedimentarios sugieren una diatexita secundaria.

Ferreira, J. A.

2014-12-01

257

Sr and Nd isotopic characteristics of 1.77-1.58 Ga rift-related granites and volcanics of the Goias tin province, Central Brazil  

International Nuclear Information System (INIS)

Supracrustal rocks of the Arai Group, together with coeval A-type granites represent a ca. 1.77-1.58 Ga old continental rift in Brazil. Two granite families are identified: the older (1.77 Ga) group forms small undeformed plutons, and the younger granites (ca. 1.58 Ga) constitute larger, deformed plutons. Sr-Nd isotopic data for these rocks indicate that the magmatism is mostly produced of re-melting of Paleoproterozoic sialic crust. Initial Sr ratios for both granite families are ca 0.276 and 0.720. Most TDM model ages are between 2.58 and 1.80 Ga. ?Nd (T) values are between +3.6 and -11.9. Arai volcanics are bimodal, with basalts and dacites/rhyolites interlayered with continental sediments. The felsic volcanics show Nd isotopic characteristics which are very similar to the granites, and are also interpreted as reworking of Paleoproterozoic crust. Detrital sediments of the Arai Group revealed TDM model ages between 2.4 and 2.16 Ga., indicating that they are the product of erosion of Paleoproterozoic crust. The data indicate that the Arai rift system was established on crust that had just become stable after the Paleoproterozoic orogeny. (author)

258

Simulations of an underground explosion in granite  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the results of a computational study performed to investigate the behavior of granite under shock wave loading conditions. A thermomechanically consistent constitutive model that includes the effects of bulking, yielding, material damage, and porous compaction on the material response was used in the simulations. The model parameters were determined based on experimental data, and the model was then used in a series of one-dimensional simulations of PILE DRIVER, a deeply-buried explosion in a granite formation at the Nevada Test Site. Particle velocity histories, peak velocity and peak displacement as a function of slant range, and the cavity radius obtained from the code simulations compared favorably with PILE DRIVER data.

Antoun, T; Glenn, L A; Lomov, I N; Vorobiev, O Y

1999-06-14

259

Physics of the granite sphere fountain  

Science.gov (United States)

A striking example of levitation is encountered in the "kugel fountain" where a granite sphere, sometimes weighing over a ton, is kept aloft by a thin film of flowing water. In this paper, we explain the working principle behind this levitation. We show that the fountain can be viewed as a giant ball bearing and thus forms a prime example of lubrication theory. It is demonstrated how the viscosity and flow rate of the fluid determine (i) the remarkably small thickness of the film supporting the sphere and (ii) the surprisingly long time it takes for rotations to damp out. The theoretical results compare well with measurements on a fountain holding a granite sphere of one meter in diameter. We close by discussing several related cases of levitation by lubrication.

Snoeijer, Jacco H.; der Weele, Ko van

2014-11-01

260

Diffusion interfaces of fractures in granitic rocks  

International Nuclear Information System (INIS)

The report presents a method to describe pore space around the major fractures in granitic rocks. The method is based on conventional technique, such as microscopy, porosity measurements and chemical analyses. The results are presented as profiles perpendicular to the fracture surface. Two types of open fracture and a partially filled carbonate fracture. In the examined cases, about 80 - 90 % of the range of variations in porosity and chemical contents were related to the first 4 - 5 mm from the fracture surface into the rock matrix. Porosity of the interface was decreased down to the reported average porosity of granites (5.2 - 0.4 % vol) within 10 - 20 mm from the fracture surface. Porosity profiles were not, however, completely stabilized within this distance. The marked trends in chemical profiles are caused by both deformation history of the rock and recent interaction between rock and water in pore space. Porosity and geochemical profiles are observed fracture specific

261

Retention of Anionic Species on Granite: Influence of Granite Composition - 12129  

Energy Technology Data Exchange (ETDEWEB)

Technetium (Tc-99, T{sub 1/2} = 2.1.10{sup 5} yrs) and selenium (Se-79, T{sub 1/2} = 6.5.10{sup 4} yrs) belong among fission products, being produced by fission of nuclear fuel. Both elements can significantly contribute to risk due to their complicated chemistry, long life times, high mobility and prevailing anionic character. Therefore, knowledge of migration behaviour under different conditions can significantly improve input into performance and safety assessment models. Granite is considered as a potential host rock for deep geological disposal of radioactive waste in many countries. Granitic rocks consist usually of quartz, feldspar, plagioclase (main components), mica, chlorite, kaolinite (minor components). The main feature of the rock is advection governed transport in fractures, complemented with diffusion process from fracture towards undisturbed rock matrix. The presented work is focused on interaction of anionic species (TcO{sub 4}{sup -}, SeO{sub 4}{sup 2-}, SeO{sub 3}{sup 2-}) with granitic rock. Furthermore, the importance of mineral composition on sorption of anionic species was also studied. The batch sorption experiments were conducted on the crushed granite from Bohemian Massive. Five fractions with defined grain size were used for static batch method. Mineral composition of each granitic fraction was evaluated using X-ray diffraction. The results showed differences in composition of granitic fractions, even though originating from one homogenized material. Sorption experiments showed influence of granite composition on adsorption of both TcO4{sup -} and SeO3{sup 2-} on granitic rock. Generally, Se(IV) showed higher retention than Tc(VII). Se(VI) was not almost sorbed at all. Fe containing minerals are pronounced as a selective Se and Tc sorbent, being reduced on their surface. As micas in granite are usually enriched in Fe, increased sorption of anionic species onto mica enriched fractions can be explained by this reason. On the other hand, fractions enriched in feldspar did not show increased sorption affinity to Tc and Se. (authors)

Videnska, Katerina [Institute of Chemical Technology, Prague (Czech Republic); Havlova, Vaclava [Nuclear Research Institute Rez, Rez, 25068 (Czech Republic)

2012-07-01

262

Geology and tin-greisen mineralization of the Akash granite, northern Arabian Shield  

Science.gov (United States)

The western margin of the postorogenic Akash granite, 30 km E of Ha'il in the northern Arabian Shield, is greisenized and contains anomalous concentrations of Sn. The pluton intrudes metamorphic and intrusive rocks, and crops out as a 10 by 15 km elliptical body with its long axis oriented N. It consists predominantly of metaluminous alkali-feldspar granite or syenogranite, with accessory biotite and muscovite, and traces of fluorite. Greisenization extends discontinuously in a zone at least 3 km long parallel to the western contact, and along E-trending hematitic quartz veins for more than 2 km from the contact. The veins occupy fractures that were probably conduits for ascending mineralizing fluids. Within about 20 m of the contact, they are enclosed in quartz—white mica greisen containing hematite, fluorite, and locally, topaz and cassiterite. Composite chip samples from the greisenized zone have an average Sn content of 710 ppm, and a maximum of 1600 ppm. Anomalous values for Zn, Fe, Mn, Mo, Bi and Cu also occur, but none of the samples contain detectable W. Three samples of hematitic quartz averaged 126 ppm Sn, and one contained 200 ppm W.

Kellogg, Karl S.; Smith, Charles W.

263

Radioactivity of some imported granite and marble  

International Nuclear Information System (INIS)

The results of gamma spectrometry analysis of some imported marble and granite samples are presented. The measurements were provided by HP Ge detector and multichannel analyzer, using Genie 2000 software. Activities of radionuclides in the examined samples are found in the range that gives gamma index below 1 (except in two cases), so that these materials can be used at indoor and outdoor building construction. (author)

264

Generating contrasting granitic melts from the same source: the ca. 3.1 Ga Heerenveen and Mpuluzi batholiths, South Africa  

Science.gov (United States)

The Mpuluzi and Heerenveen batholiths of the Barberton Granite-Greenstone Terrain (BGGT), South Africa, belong to the post-tectonic, ca. 3.1 Ga GMS (granite-monzogranite-syenite) suite. They are complex batholiths formed by successive intrusion phases; and they include a range of granitoid phases, defining at least three main magmatic series: (1) leucogranites and granites; (2) quartz-monzonites and syenogranites; (3) tonalites and relatively mafic granodiorites. Despite their close spatial and temporal association, each series is very distinct geochemically, demonstrating the coexistence of various magma types. The emplacement sequence starts with leucogranites, moving on to (slightly porphyritic) granites forming the bulk of the batholiths; to late leucogranites, syenogranites/monzonites and dark granodiorites emplacing in late, syn-magmatic shear zones. However, despite the clear emplacement sequence and the well identified, successive emplacement phases, the isotopic characteristics of the GMS batholiths are strikingly homogeneous. Zircons from 18 samples of the Mpuluzi and Heerenveen batholiths, representative of all phases and magmatic series, were dated and analysed for Hf isotopes. Regardless of the relative age and petrological type, they demonstrate emplacement ages identical within error (3106 ± 8 Ma); and, perhaps more surprinsingly, similar Hf isotopic values (?Hf(T) = -1.5 ± 0.7, corresponding to model ages of ca. 3520 Ma). This would suggest that a diverse range of granitoids, ranging from leucogranites to syenites, including both peraluminous and metaluminous compositions, and spanning both sodic and potassic compositions (0.9 < Na2O/K2O < 2.5), were all generated concomitantly (or in short succession) from the same source, or from isotopically similar sources. The lack of mafic components, associated with the crustal signature of all granitoids, implies a crustal source for the GMS granites. Regionally, both TTG plutonic rocks (Steynsdorp pluton and component of the Ancient Gneiss Complex of Swaziland, ACG), and felsic volcaniclastics and amphibolites of the Theespruit formation emplaced at ca. 3.52 Ga, and represent potential sources. In all geochemical diagrams, the different rock types do not define single trends; rather, each magmatic series define its own, individual trend, precluding the different facies to be represent a single differentiation (or mixing) series. We suggest that the various component of the GMS granitoids mirror fast melting of a composite crust. Melting of the Theespruit volcaniclastics resulted in the generation of leucogranites and granites. Melting of amphibolitic portions of the Theespruit group yielded granodiorites and tonalites. Finally, the syenogranites are the result of melting of dry lithologies - either a dry tonalitic basement (ACG), or melt-depleted portions of Theespruit volcaniclastics, that lost melt due to the extraction of the leucogranites and granites.

Moyen, Jean-François; Carrouée, Simon; Cuney, Michel; Zeh, Armin

2014-05-01

265

Geochronological (Rb-Sr and Sm-Nd) studies on intrusive gabbro and dolerite dykes from parts of Northern and Central Indian cratons: implications for the age of onset of sedimentation in Bijawar and Chattisgarh basins and uranium mineralisation  

International Nuclear Information System (INIS)

The Dargawan gabbros intrusive into the Moli Subgroup of Bijawar Group, yielded Rb-Sr whole rock isochron age of 1967 ± 140 Ma. Based on the oldest age from overlying Lower Vindhyan (1.6 Ga) and the underlying youngest basement ages (2.2 Ga), the time range of Bijawar sedimentation may be assigned as 2.1-1.6 Ga (Paleoproterozoic). Sm-Nd Model ages (TDM), obtained, for Dargawan gabbros, is c. 2876-3145 Ma. High initial 87Sr/86Sr ratio of 0.70451 (higher than the contemporary mantle) and negative ?Ndi (at 1.9 Ga) value of -1.5 to - 4.5, indicate assimilation of Archaean lower crustal component by the enriched mantle source magma at the time of gabbroic intrusion. The dolerite, from Damdama area, which is intrusive into the basement and overlying sediments of Chandrapur Group in the central Indian craton, yielded Rb-Sr internal isochron age of 1641 ± 120 Ma. The high initial 87Sr/86Sr ratio of 0.7098 and ?Ndi value of -3.5 to -3.7 (at 1.6 Ga) is due to contamination of the mantle source magma with the overlying sediments. These dolerites have younger Sm-Nd Model ages (TDM) than Dargawan gabbros as c. 2462-2675 Ma, which is similar to the age of the Sambalpur granite, from which probably sediments to this part of Chattisgarh basin are derived. Hence mixing of sediments with the Damdama dyke during its emplacement, gives rise to high initial 87Sr/86Sr and low ip>87Sr/86Sr and low initial 143Nd/144 ratios for these dykes. The c. 1600 Ma age indicates minimum age of onset of the sedimentation in the Chandrapur Group of Chattisgarh basin. Both the above mafic intrusions might have taken place in an intracratonic rift related (anorogenic) tectonic setting. This study is the first reliable age report on the onset of sedimentation in the Chandrapur Group. The total minimum time span of Chandrapur and Raipur Group may be 1.6 Ga to 1.0 Ga (Mesoproterozoic). The unconformably underlying Shingora Group of rocks of Chattisgarh Supergroup thus indicates Paleoproterozoic age (older than 1.6 Ga). Most part of the recently classified Chattisgarh Supergroup and Bijawar-Vindhyan sequence are of Mesoproterozoic-Paleoproterozoic age and not of Neoproterozoic-Mesoproterozoic age as considered earlier. Petrographic study of basic dykes from Damdama area (eastern margin of Chattisgarh Supergroup) indicated presence of primary uranium mineral brannerite associated with goethite. This is the evidence of mafic intrusive providing geotherm and helping in scavenging the uranium from the surrounding and later alterations causing remobilisation and reconcentration of pre-existing uranium in host rocks as well as in mafic dyke itself otherwise mafic rocks are poor source of uranium and can not have primary uranium minerals initially. It can be concluded that mafic dykes have role in uranium mineralisation although indirectly. (author)

266

Diffusion of uranium in the granite rock  

International Nuclear Information System (INIS)

In the safety assessment of high level radioactive waste disposal, a significant retardation factor of radionuclides leaking from an underground repository can be expected. When radionuclides released from an underground repository are transported with the moving groundwater along cracks in the rock, the radionuclides will be retarded by not only adsorption on the surface of the cracks but also by process diffusion into submicron pores of rock matrix. In this experiments have been performed by process diffusion of uranium in water saturated granite. The measured penetration profile of uranium was composed of two parts. This profile was successfully explained by considering two diffusion paths in granite rock. One diffusion path was possibly a fissure with a width of few microns and another was a submicron pores of granite rock. The orders of magnitude of diffusivities for uranium were 10-12 m2/sec through the fissure and 1015 m2/sec through the submicron pores. The difference between the diffusivities of two path is thought to be caused by small geometrical factor of submicron pores, if to compared with fissures. (author)

267

Degradation studies on granite in alkaline solution  

International Nuclear Information System (INIS)

Batch leaching experiments of granite with the artificial cement leachate and the leachate of low-alkalinity-cement (LW) were carried out to evaluate the effect of the hiperalkaline plume on the environment of the high-level and TRU radioactive waste repository. Dissolution of Si and Al from feldspar included in the granite and precipitation of C-S-H were confirmed from the results of the leaching experiments with artifitial cement leachate. From this result it was found that the composition of surrounding rock changed. It also suggested that the retardation factor of migration of radionuclides would change. On the contrary, only decrease of concentrations in Si, Al and Ca in the leachate was observed in the experiment with LW. This result might indicate that C-S-H and/or C-A-S-H precipitated as secondary minerals in the LW case. From these results, it was considered that the hyperalkaline plume from the cementitious leachate might caused the change of disposal conditions such as the change in distribution coefficients of rock by precipitation of the secondary mineral and the increase in hydraulic conductivity by the dissolution of rock. On the other hand, the influences of the LW would be comparatively small, because LW and granite might equilibrate in short time. (author)

268

'Superagers' Seem to Have 'Younger' Brains, Researchers Find  

Science.gov (United States)

... page, please enable JavaScript. 'Superagers' Seem to Have 'Younger' Brains, Researchers Find Their sharp memories at 80 and beyond may provide clues for treating dementia (*this news item will not be available after ...

269

Watch Upper Number on Blood Pressure for Younger Adults  

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... sharing features on this page, please enable JavaScript. Watch Upper Number on Blood Pressure for Younger Adults: ... the difference was 23 percent. The readings to watch for: systolic pressure of 140 mm Hg or ...

270

CDC Vital Signs: Preventing Pregnancies in Younger Teens  

Science.gov (United States)

... of social media and digital technology (e.g., cell phones, computers, tablets). Younger teens can: Know both they ... maintained by: Office of the Associate Director for Communications (OADC) Home A-Z Index Policies Using this ...

271

The SHRIMP zircon U-Pb dating and its geological significance on the volcanic-intrusive rocks in broken crater of Xunwu, Jiangxi province  

International Nuclear Information System (INIS)

Xunwu broken crater located in the transition zone of Wuyi rise belt and Nanling tectonic belt, controlled by the NE direction Huichang-Xunwu fault belt and the EW direction Sannan-Xunwu fault belt,and developed a volcanic-intrusive rocks that made up of porphyroclastic lava and granite-porphyry. The zircon U-Pb dating with a higher accuracy yields the following results: the age of pyroclastic rocks in the volcanic-intrusive rocks in broken crater is (96.7±1.1) Ma and the age of granite-porphyry is (97.3±0.9) Ma. According to the geological chronology,the boundary between the Early Cretaceous and the Late Cretaceous is (99.6±0.9)Ma, the geological age of the volcanic-intrusive rocks of Xunwu broken crater is early Late Cretaceous. Age determinations of the volcanic-intrusive rocks provide the age evidence for Xunwu broken crater which belong to Yousheng formation. (authors)

272

The Paleoproterozoic Nattanen-type granites in northern Finland and vicinity – a postcollisional oxidized A-type suite  

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Full Text Available The ~1.8 Ga Nattanen-type granites in the Finnish Lapland and western Kola Peninsula are found as several relatively small, high-level, discordant plutons that are easily discernible as weak maxima on aeromagnetic maps. We present U–Pb mineral isotope data on the Finnishplutons. The concordia ages are in the 1.79?1.77 Ga range and there is little evidence for inheritance. Initial radiogenic isotope compositions (our common-Pb data combined with previously published whole-rock Nd and Hf data imply a major, yet varying, Archeansource component. Elemental geochemical data on five Finnish intrusions (the Nattanen stock, the Tepasto and Pomovaara complexes, the Riestovaara and Vainospää batholiths, as well as associated dyke rocks allow the Nattanen-type granites to be classified as oxidizedA-type granites. Their petrogenesis may be related to partial melting of the lower crust by mafic underplating (extensional setting or as a result of thermal relaxation in thickened crustal setting.

Esa Heilimo

2009-06-01

273

Episodic granitoid emplacement in the western Kaapvaal Craton: evidence from the Archæan Kraaipan granite-greenstone terrane, South Africa  

Science.gov (United States)

Field, petrological, geochemical, isotopic and geophysical data have been assembled to determine the nature and extent of Archæan Kraaipan granite-greenstone rocks on the western edge of the Kaapvaal Craton, southern Africa. The Kraaipan greenstone belts, consisting of metamorphosed mafic volcanic rocks and interlayered metasediments (mainly banded iron formations, jaspilites and ferruginous cherts), occur poorly exposed beneath cover sequences comprising mainly Neoarchæan Ventersdorp Supergroup volcanic rocks and a blanket of Tertiary-Recent Kalahari sediments. A variety of granitoid rocks intruded the Kraaipan greenstones, which, on the basis of whole rock Pb?Pb dating of banded iron formations, have yielded an age of 3410+61/-64 Ma. The earliest granitic rocks, which comprise tonalites and trondhjemitic gneisses, were dated using the single grain Pb evaporation technique on zircons, and yielded minimum ages ranging from 3162±8 to 3070±7 Ma in the study area. This, coupled with 3250-3030 Ma ages reported for gneisses in the Kimberley and other areas on the western edge of the Kaapvaal Craton, suggests a prolonged evolution for the basement gneisses which were also disturbed between 2940 and 2816 Ma ago, probably during episodes of migmatisation. Potassium-rich granitoids, also dated using the single grain Pb evaporation method, range in age from 2880±2 to 2846±22 Ma and extend from the Schweizer-Reneke area in the south to the Botswana border and beyond in the north. Geophysical evidence (aeromagnetic and Bouguer gravity data) suggest that the intrusions may be interconnected and might have been emplaced episodically across the study area. A close spatial relationship exists between these granodiorites and adamellites, and known Au mineralisation present in the Kraaipan-Madibe areas in the north and the Amalia area in the south. This suggests a possible genetic link which could be of significance in mineral exploration. Lastly, a late granitoid pluton, the Mosita Adamellite, yielded a Pb evaporation age of 2749±3 Ma and is the youngest intrusive body recorded in the Kraaipan granite-greenstone terrane. Its presence beneath Kalahari sand cover is defined by Bouguer gravity data. The Kraaipan granite-greenstone terrane, with a prominent north-south trend, appears to represent an Archæan crustal segment that may have accreted episodically on to the western edge of the Kaapvaal Craton. In a manner similar to the Murchison granite-greenstone terrane in the northeastern part of the craton, the region may also have constituted an important potential source of placer Au mineralisation found in the Witwatersrand Basin.

Anhaeusser, Carl R.; Walraven, Feo

1999-02-01

274

U-Th-Pb systematics in hydrothermally altered granites from the Granite Mountains, Wyoming  

International Nuclear Information System (INIS)

U-Th-Pb systematics were investigated in 15 samples representing two types of deuterically altered Archean granite from Wyoming. The loss of K-feldspar during both types of deuteric alteration was accompanied by an extreme reduction of Pb content from roughly 40 ppm to less than 12 ppm in the most altered samples. Nine of the 15 samples yield anomalously young whole-rock Pb-Pb and Th-Pb ages compared to concordia ages for zircons and to whole-rock Pb-Pb and Th-Pb ages for samples of unaltered granite. The young ages are interpreted to be the result of radiogenic Pb loss during a middle Proterozoic metamorphism that disturbed several isotopic systems in the unaltered granite. The results are discussed. (author)

275

Late Triassic Porphyritic Intrusions And Associated Volcanic Rocks From The Shangri-La Region, Yidun Terrane, Eastern Tibetan Plateau: Implications For Adakitic Magmatism And Porphyry Copper Mineralization  

Science.gov (United States)

The Yidun terrane, located on the eastern margin of the Tibetan plateau, has been commonly considered to be a Triassic volcanic arc produced by subduction of the Ganzi-Litang oceanic lithosphere. The Yidun terrane is characterized by numerous arc-affinity granitic intrusions located along a 500-km-long, north-south-trending belt. Among these granitic bodies, several small porphyritic intrusions in the southern segment of the terrane (Shangri-La region) are associated with large porphyry copper deposits. These porphyritc intrusions are composed of diorite and quartz diorite, and spatially associated with andesites and dacites. LA-ICP-MS zircon U-Pb ages of the intrusions range from 230 to 215 Ma. The andesites and dacites are intercalated with slates and sandstones and have ages of around 220 Ma. The intrusive and volcanic rocks have SiO2 contents from 56.6 to 67.1 wt.%, Al2O3 from 14.2 to 17.4 wt.% and MgO from 1.9 to 4.2 wt.%. They show significant negative Nb-Ta anomalies on primitive mantle-normalized spidergrams. They have high La/Yb (13-49) ratios with no prominent Eu anomalies. All the rocks have high Sr (258-1980 ppm), and low Y (13-21 ppm) with high Sr/Y ratios (29-102). The geochemical features indicate that both the volcanic rocks and porphyritic intrusions were derived from adakitic magmas. They have similar initial 87Sr/86Sr ratios (0.7058 to 0.7077) and ?Nd (-1.88 to -4.93) values, but can be further divided into two groups: high silica (HSA) and low silica adakitic rocks (LSA). The HSA, representing an early stage of magmatism (230 to 215 Ma), were derived from oceanic slab melts with limited interaction with the overlying mantle wedge. At 215 Ma, more extensive interaction resulted in the formation of LSA. We propose that HSA were produced by flat subduction leading to melting of oceanic slab, whereas subsequent slab break-off caused the significant interaction between slab melts and the mantle wedge and thus the generation of the LSA. Compared with barren granitic intrusions in the northern Yidun terrane, the copper mineralization in the Shangri-La porphyritic intrusions was likely related to slab-derived adakitic magma.

Wang, B.; Zhou, M.; Li, J.; Yan, D.

2011-12-01

276

A Distributed Network Intrusion Detection System with Active Surveillance Agent  

OpenAIRE

A distributed network intrusion detection system (IDS) called SA-NIDS is proposed based on the network-based intrusion detection architecture. It includes three basic components, Local Intrusion Detection Monitor (LIDM), Global Intrusion Detection Controller (GIDC), and Surveillance Agent (SA). Basically, the LIDM is used to do packets capturing, packets de-multiplexing, local intrusion detection and intrusion inferring. The GIDC is installed in administration center for communicating and man...

Bin Zeng; Lu Yao; Rui Wang

2013-01-01

277

Intrusion-Aware Alert Validation Algorithm for Cooperative Distributed Intrusion Detection Schemes of Wireless Sensor Networks  

Directory of Open Access Journals (Sweden)

Full Text Available Existing anomaly and intrusion detection schemes of wireless sensor networks have mainly focused on the detection of intrusions. Once the intrusion is detected, an alerts or claims will be generated. However, any unidentified malicious nodes in the network could send faulty anomaly and intrusion claims about the legitimate nodes to the other nodes. Verifying the validity of such claims is a critical and challenging issue that is not considered in the existing cooperative-based distributed anomaly and intrusion detection schemes of wireless sensor networks. In this paper, we propose a validation algorithm that addresses this problem. This algorithm utilizes the concept of intrusion-aware reliability that helps to provide adequate reliability at a modest communication cost. In this paper, we also provide a security resiliency analysis of the proposed intrusion-aware alert validation algorithm.

Young-Jae Song

2009-07-01

278

Intrusion-aware alert validation algorithm for cooperative distributed intrusion detection schemes of wireless sensor networks.  

Science.gov (United States)

Existing anomaly and intrusion detection schemes of wireless sensor networks have mainly focused on the detection of intrusions. Once the intrusion is detected, an alerts or claims will be generated. However, any unidentified malicious nodes in the network could send faulty anomaly and intrusion claims about the legitimate nodes to the other nodes. Verifying the validity of such claims is a critical and challenging issue that is not considered in the existing cooperative-based distributed anomaly and intrusion detection schemes of wireless sensor networks. In this paper, we propose a validation algorithm that addresses this problem. This algorithm utilizes the concept of intrusion-aware reliability that helps to provide adequate reliability at a modest communication cost. In this paper, we also provide a security resiliency analysis of the proposed intrusion-aware alert validation algorithm. PMID:22454568

Shaikh, Riaz Ahmed; Jameel, Hassan; d'Auriol, Brian J; Lee, Heejo; Lee, Sungyoung; Song, Young-Jae

2009-01-01

279

Intrusion-aware Alert Validation Algorithm for Cooperative Distributed Intrusion Detection Schemes of Wireless Sensor Networks  

CERN Document Server

Existing anomaly and intrusion detection schemes of wireless sensor networks have mainly focused on the detection of intrusions. Once the intrusion is detected, an alerts or claims will be generated. However, any unidentified malicious nodes in the network could send faulty anomaly and intrusion claims about the legitimate nodes to the other nodes. Verifying the validity of such claims is a critical and challenging issue that is not considered in the existing cooperative-based distributed anomaly and intrusion detection schemes of wireless sensor networks. In this paper, we propose a validation algorithm that addresses this problem. This algorithm utilizes the concept of intrusion-aware reliability that helps to provide adequate reliability at a modest communication cost. In this paper, we also provide a security resiliency analysis of the proposed intrusion-aware alert validation algorithm.

Shaikh, Riaz Ahmed; Auriol, Brian J d; Lee, Heejo; Lee, Sungyoung; Song, Young-Jae; 10.3390/s90805989

2009-01-01

280

Relationships between deformation and magmatism in the Pan-African Kandi Shear Zone: Microstructural and AMS studies of Ediacaran granitoid intrusions in central Bénin (West Africa)  

Science.gov (United States)

Relationships between the metamorphic basement, granitic intrusions and the Kandi Shear Zone (KSZ) in central Bénin have been investigated using petrological and structural approaches, in order to better understand the space and time parameters of the Pan-African shear deformation and the Ediacaran magmatism. In central Bénin, metamorphic rocks from the KSZ display a steep to vertical N-S trending foliation, a sub-horizontal mineral lineation together with kinematic indicators in agreement with a dextral transcurrent mega-shear zone. Four granitic intrusions (Dassa, Tré, Gobada and Tchetti) show many petrological similarities. They are biotite ± amphibole - ilmenite ± magnetite monzogranites with ferrous and metaluminous I-type features derived from high-K calk-alkaline magma. A fifth intrusion (Fita) is an alkali-feldspar, biotite, magnetite and ilmenite bearing granite crystallized from an alkaline magma. Moreover, high K2O, Zr, Y, Nb and low CaO, MgO and Al2O3 contents together with high (FeOt/MgO) and low LIL/HFS elements ratios suggesting an A-type granite affinity. Microstructural and AMS investigations presented in this paper show (i) solid-state deformation evidence for Dassa pluton and (ii) a magmatic deformation for the Tré, Tchetti, Gobada and Fita granitoids. Foliation in Dassa is parallel to the mesoscopic planar mylonitic foliation of the metamorphic basement. In the Tré, Tchetti, Gobada and Fita granitoids, magmatic textures and magnetic fabrics are coherent with the KSZ activity. These data suggest (i) a syn-kinematic nature for most of the intrusions (Tré, Gobada, Tchetti and Fita), except Dassa which correspond to an earlier event (ii) the succession of high-K calk-alkaline (Dassa, Tré, Gobada, Tchetti) evolves toward alkaline magmas (Fita) during the KSZ strike-slip tectonics. These observations highlight the changing nature of magma composition, magmatic processes and the different sources during KSZ activity in the Bénin Nigerian Shield. These new results suggest that the previous geodynamic interpretations, which assume a post-tectonic emplacement for the Gobada intrusion or an active continental margin setting for most of the late Pan-African (Ediacaran) granites intruded in central Bénin, has to be re-examined.

Adissin Glodji, L.; Bascou, J.; Yessoufou, S.; Ménot, R.-P.; Villaros, A.

2014-09-01

281

Natural radioactivity of granites used as building materials  

International Nuclear Information System (INIS)

Sixteen kinds of different granites, used as building materials, imported to Greece mainly from Spain and Brazil, were sampled and their natural radioactivity was measured by gamma-ray spectrometry. The activity concentrations of 238U, 226Ra, 232Th and 4K of granites are presented and compared to those of other building materials as well as other granite types used all over the world. In order to assess the radiological impact from the granites investigated, the absorbed and the effective doses were determined. Although the annual effective dose is higher than the limit of 1 mSv y-1 for some studied granites, they could be used safely as building materials, considering that their contribution in most of the house constructions is very low. An attempt to correlate the relatively high level of natural radioactivity, shown by some of the granites, with their constituent radioactive minerals and their chemical composition, was also made

282

Portuguese granites associated with Sn-W and Au mineralizations  

Directory of Open Access Journals (Sweden)

Full Text Available In northern and central Portugal, there are different tin-bearing granites. Most of them are of S-type, others have mixed characteristics of I-type and S-type granites and a few are of I-type. Tin-tungsten deposits are commonly associated with Hercynian tin-bearing S-type granites. Some quartz veins with wolframite are associated with an I-type granite, which has a low Sn content. In suites of tin-bearing S-type granitic rocks, Sn content increases as a function of the degree of fractional crystallization. Greisenizations of two-mica S-type granites associated with tin-tungsten mineralizations are accompanied by an increase in SiO2, H2O+, Sn, W, Nb, Ta, Rb, Zn, and Pb and decrease in MgO, Na2O, V, Sc,Zr, and Sr. The granite associated with the Jales gold deposit is of S-type and strongly differentiated like the tin-bearing S-type granites, but it has a very low Sn content. During fractional crystallization, Si, Rb, Sn, Pb, Au, As, Sb, and S increase. During increasing degree of hydrothermal alteration of this granite at the gold-quartz vein walls, there are progressive increases in K2O, H2O+, Sn, Cs, Cu, Pb, Au, Sb, As, and S.

Ana M.R. Neiva

2002-01-01

283

Diffusion experiment of a radionuclide in granitic rock cores  

International Nuclear Information System (INIS)

An effective diffusion coefficient of neptunium-237 which is one of hazardous long-lived radionuclide including high level radioactive waste was determined by using 40 mm diameter and 5 mm thick disks under an aerobic condition. An alpha autoradiography was performed for cross sections of a 20 mm thick granite disk to study the penetrated neptunium into granite. The effective diffusion coefficient of neptunium diffused through a water saturated granite was about 2.5 x 10-13 m2/sec. The autoradiograph of solid state track detectors clearly showed that biotite constituting granite has storage pores and keep diffusing species in it. (author)

284

Classification of intrusions of terrigenous rocks into coal seams  

Energy Technology Data Exchange (ETDEWEB)

This paper presents classification of rock intrusions into coal seams considering the following factors: intrusion shape, dimensions and size in relation to coal seam thickness. In regard to shape intrusions are divided into 5 groups: 1. U-shaped, 2. V-shaped, 3. bowl-shaped, 4. pearl-like (with diameter increasing from intrusion entrance in the direction of coal seam floor), 5. band-shaped intrusions. In regard to intrusion dimensions they are classified as: narrow (0-0.5 m), medium (0.5 - 1.5 m), wide (1.5 - 3.0 m), very wide (over 3.0 m). Considering intrusion size in relation to coal seam thickness three classes are proposed: intrusion not exceeding 25% of seam thickness, intrusions which range from 25 to 50% of seam thickness, intrusions exceeding 50% of seam thickness. Intrusions caused by sandstones, argillites and aleurites in the coal seam roofs are discussed.

Shul' ga, V.F.; Vashchenko, V.I.

1981-09-01

285

Intrusion detection using secure signatures  

Energy Technology Data Exchange (ETDEWEB)

A method and device for intrusion detection using secure signatures comprising capturing network data. A search hash value, value employing at least one one-way function, is generated from the captured network data using a first hash function. The presence of a search hash value match in a secure signature table comprising search hash values and an encrypted rule is determined. After determining a search hash value match, a decryption key is generated from the captured network data using a second hash function, a hash function different form the first hash function. One or more of the encrypted rules of the secure signatures table having a hash value equal to the generated search hash value are then decrypted using the generated decryption key. The one or more decrypted secure signature rules are then processed for a match and one or more user notifications are deployed if a match is identified.

Nelson, Trent Darnel; Haile, Jedediah

2014-09-30

286

Leaky cable intrusion detection sensors  

International Nuclear Information System (INIS)

Buried Line Field Disturbance Sensors used for the purpose of outdoor perimeter intrusion detection are unique in the sense that they are covert and terrain following. Considerable effort has been spent in recent years to develop an effective Buried Line Sensor using leaky (or ported) cable technology. To date, a modular CW (Continuous Wave) approach to designing such a sensor has proven to be the most effective compromise in terms of cost, performance and installation. Proper design of a leaky cable sensor requires an in-depth knowledge of the coupling performance and attenuation characteristics of the sensor cable to be used. The ''Forward Wave'' (codirectional) method of detection is discussed. This paper contains theoretical and experimental expressions developed to demonstrate operation in terms of cost, performance and ease of installation

287

High temperature hydrothermal fibrolite in «El Payo Granite», Cadalso-Casillas de Flores granitic complex (Salamanca-Caceres, Spain)  

OpenAIRE

Subsolidus replacements of fibrolite after biotite, muscovite, andalusite and feldspars have been recognized in El Payo granite near the contact with the more evolved Casillas granite. Both granites form part of the late-Variscan Cadalso-Casillas de Flores plutonic massif. Replacements follow microfractures and grain boundaries and are associated with fibrolite-quartz and less commonly fibrolite-tourmaline intergrowths. The limits of the altered zone are imprecise but the latter seems to be a...

Hassan Mohamud, A.; Casquet Marti?n, Ce?sar; Pe?rez Del Villar, L.; Cozar, J.; Pellicer Bautista, Mari?a Jose?

2002-01-01

288

Data Access by Data Intrusion  

Directory of Open Access Journals (Sweden)

Full Text Available The mining is a source for the data base as it requires several elements and techniques for the retrieval operations. Some techniques and their corresponding technologies have an important role in the database which is required in large amounts for data access. The primary method is to retrieve the relevant data and the secondary is retrieval of the matched data. Generally the data ware houses is much more than an information technology project for the companies embracing the concept of mass customization. The Armed data warehouses filled with quality information but one has to use mass customization techniques and scientific testing methods to expand the customer based from one million to 10 million in 10 year’s period. The mass customization is ultimate use of data ware housing and the mining techniques which are making the integral part of the business process. Just like the arms, a data ware house and data mining increases the strength with the active use. With every new test and new product valuable information is added and at the same time information is retrieved, modified which allows the analysts to learn from the successes and the failures of the past. The paper is mainly concerned with retrieval operation by enforcing these failures and successful operation in the form of data intrusion. The data intrusion helps in recognizing the data in the form of mass storage and can be retrieved the relevant data. It is simple and one of the techniques which can cope up with the business market.

SarathChand P.V

2011-09-01

289

Tourmaline occurrences within the Penamacor-Monsanto granitic pluton and host-rocks (Central Portugal): genetic implications of crystal-chemical and isotopic features  

Science.gov (United States)

Tourmalinization associated with peraluminous granitic intrusions in metapelitic host-rocks has been widely recorded in the Iberian Peninsula, given the importance of tourmaline as a tracer of granite magma evolution and potential indicator of Sn-W mineralizations. In the Penamacor-Monsanto granite pluton (Central Eastern Portugal, Central Iberian Zone), tourmaline occurs: (1) as accessory phase in two-mica granitic rocks, muscovite-granites and aplites, (2) in quartz (±mica)-tourmaline rocks (tourmalinites) in several exocontact locations, and (3) as a rare detrital phase in contact zone hornfels and metapelitic host-rocks. Electron microprobe and stable isotope (?18O, ?D, ?11B) data provide clear distinctions between tourmaline populations from these different settings: (a) schorl-oxyschorl tourmalines from granitic rocks have variable foititic component (X? = 17-57 %) and Mg/(Mg + Fe) ratios (0.19-0.50 in two-mica granitic rocks, and 0.05-0.19 in the more differentiated muscovite-granite and aplites); granitic tourmalines have constant ?18O values (12.1 ± 0.1 ‰), with wider-ranging ?D (-78.2 ± 4.7 ‰) and ?11B (-10.7 to -9.0 ‰) values; (b) vein/breccia oxyschorl [Mg/(Mg + Fe) = 0.31-0.44] results from late, B- and Fe-enriched magma-derived fluids and is characterized by ?18O = 12.4 ‰, ?D = -29.5 ‰, and ?11B = -9.3 ‰, while replacement tourmalines have more dravitic compositions [Mg/(Mg + Fe) = 0.26-0.64], close to that of detrital tourmaline in the surrounding metapelitic rocks, and yield relatively constant ?18O values (13.1-13.3 ‰), though wider-ranging ?D (-58.5 to -36.5 ‰) and ?11B (-10.2 to -8.8 ‰) values; and (c) detrital tourmaline in contact rocks and regional host metasediments is mainly dravite [Mg/(Mg + Fe) = 0.35-0.78] and oxydravite [Mg/(Mg + Fe) = 0.51-0.58], respectively. Boron contents of the granitic rocks are low (tourmaline saturation in granitic melts, implying loss of B and other volatiles to the surrounding host-rocks during the late-magmatic stages. This process was responsible for tourmalinization at the exocontact of the Penamacor-Monsanto pluton, either as direct tourmaline precipitation in cavities and fractures crossing the pluton margin (vein/breccia tourmalinites), or as replacement of mafic minerals (chlorite or biotite) in the host-rocks (replacement tourmalinites) along the exocontact of the granite. Thermometry based on 18O equilibrium fractionation between tourmaline and fluid indicates that a late, B-enriched magmatic aqueous fluid (av. ?18O ~12.1 ‰, at ~600 °C) precipitated the vein/breccia tourmaline (?18O ~12.4 ‰) at ~500-550 °C, and later interacted with the cooler surrounding host-rocks to produce tourmaline at lower temperatures (400-450 °C), and an average ?18O ~13.2 ‰, closer to the values for the host-rock. Although B-metasomatism associated with some granitic plutons in the Iberian Peninsula seems to be relatively confined in space, extending integrated studies such as this to a larger number of granitic plutons may afford us a better understanding of Variscan magmatism and related mineralizations.

da Costa, I. Ribeiro; Mourão, C.; Récio, C.; Guimarães, F.; Antunes, I. M.; Ramos, J. Farinha; Barriga, F. J. A. S.; Palmer, M. R.; Milton, J. A.

2014-04-01

290

Transition from oceanic to continental lithosphere subduction in southern Tibet: Evidence from the Late Cretaceous-Early Oligocene (~ 91-30 Ma) intrusive rocks in the Chanang-Zedong area, southern Gangdese  

Science.gov (United States)

Little is known about the detailed processes associated with the transition from oceanic to continental lithosphere subduction in the Gangdese Belt of southern Tibet (GBST). Here, we report zircon U-Pb age, major and trace element and Sr-Nd-Hf isotopic data for Late Cretaceous-Early Oligocene (~ 91-30 Ma) intermediate-acid intrusive rocks in the Chanang-Zedong area immediately north of the Yarlung-Tsangpo suture zone. These rocks represent five magmatic episodes at ~ 91, ~ 77, ~ 62, ~ 48, and ~ 30 Ma, respectively. The 91-48 Ma rocks have slightly lower initial 87Sr/86Sr (0.7037 to 0.7047), and higher ?Nd(t) (+ 1.8 to + 4.3) and ?Hf(t) (+ 3.5 to + 14.7) values in comparison with those (0.7057 to 0.7062, - 3.3 to - 2.5 and + 2.2 to + 6.6) of the ~ 30 Ma intrusive rocks. The ~ 91, ~ 62 and ~ 30 Ma rocks are geochemically similar to slab-derived adakites. The ~ 91 Ma Somka adakitic granodiorites were likely derived by partial melting of the subducting Neo-Tethyan oceanic crust with minor oceanic sediments, and the ~ 91 Ma Somka dioritic rocks with a geochemical affinity of adakitic magnesian andesites likely resulted from interactions between adakitic magmas and overlying mantle wedge peridotite. The ~ 77 Ma Luomu diorites were probably generated by partial melting of juvenile basaltic lower crust. The ~ 62 Ma Naika and Zedong adakitic diorites and granodiorites were likely generated mainly by partial melting of thickened juvenile mafic lower crust but the source region of the Zedong adakitic rocks also contained enriched components corresponding to Indian continental crust. The ~ 48 Ma Lamda granites were possibly generated by melting of a juvenile basaltic crust. The younger (~ 30 Ma) Chongmuda adakitic quartz monzonites and minor granodiorites were most probably derived by partial melting of Early Oligocene northward-subducted Indian lower crust beneath the southern Lhasa Block. Taking into account the regional tectonic and magmatic data, we suggest that the Gangdese Belt of southern Tibet (GBST) underwent a tectonodynamic transition from oceanic subduction to continental subduction between 100 and 30 Ma. It evolved through four stages: 100-65 Ma roll-back of subducted Neo-Tethyan oceanic lithosphere; 65-60 Ma initial collision between Indian and Asian continents; 60-40 Ma breakoff of subducted Neo-Tethyan oceanic lithosphere; and ~ 30 Ma northward subduction of the Indian continent.

Jiang, Zi-Qi; Wang, Qiang; Wyman, Derek A.; Li, Zheng-Xiang; Yang, Jin-Hui; Shi, Xiao-Bing; Ma, Lin; Tang, Gong-Jian; Gou, Guo-Ning; Jia, Xiao-Hui; Guo, Hai-Feng

2014-05-01

291

Characterization of Climax granite ground water  

Energy Technology Data Exchange (ETDEWEB)

The Climax ground water fails to match the commonly held views regarding the nature of deep granitic ground waters. It is neither dilute nor in equilibrium with the granite. Ground-water samples were taken for chemical analysis from five sites in the fractured Climax granite at the Nevada Test Site. The waters are high in total dissolved solids (1200 to 2160 mg/L) and rich in sodium (56 to 250 mg/L), calcium (114 to 283 mg/L) and sulfate (325 to 1060 mg/L). Two of the samples contained relatively high amounts of uranium (1.8 and 18.5 mg/L), whereas the other three contained uranium below the level of detection (< 0.1 mg/L). The pH is in the neutral range (7.3 to 8.2). The differences in composition between samples (as seen in the wide range of values for the major constituents and total dissolved solids) suggest the samples came from different, independent fracture systems. However, the apparent trend of increasing sodium with depth at the expense of calcium and magnesium suggests a common evolutionary chemical process, if not an interconnected system. The waters appear to be less oxidizing with depth (+ 410 mV at 420 m below the surface vs + 86 mV at 565 m). However, with Eh measurements on only two samples, this correlation is questionable. Isotopic analyses show that the waters are of meteoric origin and that the source of the sulfate is probably the pyrite in the fracture-fill material. Analysis of the measured water characteristics using the chemical equilibrium computer program EQ3 indicates that the waters are not in equilibrium with the local mineral assemblage. The solutions appear to be supersaturated with respect to the mineral calcite, quartz, kaolinite, muscovite, k-feldspar, and many others.

Isherwood, D.; Harrar, J.; Raber, E.

1982-08-01

292

Characterization of Climax granite ground water  

International Nuclear Information System (INIS)

The Climax ground water fails to match the commonly held views regarding the nature of deep granitic ground waters. It is neither dilute nor in equilibrium with the granite. Ground-water samples were taken for chemical analysis from five sites in the fractured Climax granite at the Nevada Test Site. The waters are high in total dissolved solids (1200 to 2160 mg/L) and rich in sodium (56 to 250 mg/L), calcium (114 to 283 mg/L) and sulfate (325 to 1060 mg/L). Two of the samples contained relatively high amounts of uranium (1.8 and 18.5 mg/L), whereas the other three contained uranium below the level of detection (< 0.1 mg/L). The pH is in the neutral range (7.3 to 8.2). The differences in composition between samples (as seen in the wide range of values for the major constituents and total dissolved solids) suggest the samples came from different, independent fracture systems. However, the apparent trend of increasing sodium with depth at the expense of calcium and magnesium suggests a common evolutionary chemical process, if not an interconnected system. The waters appear to be less oxidizing with depth (+ 410 mV at 420 m below the surface vs + 86 mV at 565 m). However, with Eh measurements on only two samples, this correlation is questionable. Isotopic analyses show that the waters are of meteoric origin and that the source of the sulfate is probably the pyrite in the fracture-fill material. Analysis of the measured water characteristics using the chemical equilibrium computer program EQ3 indicates that the waters are not in equilibrium with the local mineral assemblage. The solutions appear to be supersaturated with respect to the mineral calcite, quartz, kaolinite, muscovite, k-feldspar, and many others

293

Resaturation of backfilled tunnels in granite  

International Nuclear Information System (INIS)

Highly compacted bentonite clay is proposed for use as a backfill material around high level waste overpacks to be placed in excavated tunnels in the crystalline bedrock of Northern Switzerland. Initially the bentonite will have a low residual water content and with time the bentonite will resaturate due to the influx of water from the crystalline rock. The time and degree of bentonite saturation are important for safety assessment because of their effect on the corrosion of the waste overpack, on the leaching of the waste matrix, and on the radionuclide transport in the backfill. A three-dimensional, two-phase flow model (FAMOS) is used to quantify the expected resaturation under the conditions outlined above. The time required for complete saturation simulated using FAMOS ranges from less than 100 to more than 1000 years. These results are comparable to the results of diffusive models of bentonite saturation when using a diffusion coefficient of 3x10-10 m2s-1. The time depends on the hydraulic properties of the bentonite as well as the saturated hydraulic conductivity of the crystalline rock. At saturated granite hydraulic conductivities of the order of 10-9 ms-1 the bentonite becomes fully saturated in less than 100 years. For saturated granite hydraulic conductivities of the order of 10-12 ms-1 the bentonite becomes fully saturated in several hundred to over 1000 years. For a given granite hydraulic conductivity the degree of saturation depends on the bentonite capillary pressure versus water saturation characteristic relationships. For high capillary pressures (of the order of 105 kPa) the bentonite saturates relatively quickly; with lower capillary pressures the time for complete saturation increases

294

Simulation of bentonite colloid migration through granite  

International Nuclear Information System (INIS)

Document available in extended abstract form only. Full text of publication follows: Colloidal bentonite particles generate at the interface of buffer and host rock in spent nuclear fuel repository due to an erosion process and migrate through granite by the water flow. Stability of these colloids and their migration possibilities have been studied on account of radionuclide transport possibility as colloid could carry adsorbed radionuclides in groundwater through granite. That is why a simulation of bentonite colloid migration in the surrounding of a repository might be requested. According to chemical condition as ionic strength and pH, the colloidal particles coagulate into clusters and that influence the migration of particles. The coagulation kinetics of natural bentonite colloids were experimentally studied in many articles, for example by light scattering techniques. We created a model of coagulation of bentonite colloids and simulation of a chosen experiment with use of the multicomponent reactive transport equation. The coagulation model describes clustering of particles due to attractive van der Waals forces as result of collision of particles due to heat fluctuation and different velocity of particles during sedimentation and velocity gradient of water flow. Next, the model includes influence of repulsive electrostatic forces among colloidal particles leading to stability of particles provided high surface charge of colloids. In the model, each group of clu colloids. In the model, each group of clusters is transported as one solution component and the kinetics of coagulation are implemented as reactions between the components: a shift of particles among groups of particles with similar migration properties, according to size of the clusters of colloids. The simulation of migration of bentonite colloid through granite using the coagulation model was calibrated according to experiment results. On the basis of the simulation, one can estimate the basic processes that occur during bentonite colloid migration. That could be useful for prediction of spent nuclear fuel repository safety with the help of model of bentonite colloid behavior during migration. (authors)

295

Contrasting zircon morphology and UPb systematics in peralkaline and metaluminous post-orogenic granite complexes of the Arabian Shield, Kingdom of Saudi Arabia  

Science.gov (United States)

Uzircon ages are reported for seven metaluminous-to-peralkaline post-orogenic granites from the Late Proterozoic Arabian Shield of Saudi Arabia. Zircons from the metaluminous rocks are prismatic, with length-to-width ratios of ??? 2-4: 1 and small pyramidal terminations. In contrast, zircons from three of the four peralkaline complexes either lack well-developed prismatic faces (are pseudo-octahedral) or are anhedral. Some zircons from the peralkaline granites contain inherited radiogenic Pb and have very high common Pb contents (206Pb/204Pb < 150), making the UPb method poorly suited for determining the age of these rocks. Zircons in the metaluminous granites do not contain inheritance and yield well-defined concordia intercepts. The span of ages of the seven complexes (670-470 Ma) indicates that post-orogenic granitic magmatism was not a singular event in the Arabian Shield but rather occurred as multiple intrusive episodes from the Late Proterozoic to the Middle Ordovician. ?? 1989.

Aleinikof, J.N.; Stoeser, D.B.

1989-01-01

296

A-type and I-type granitoids and mylonitic granites of Hassan Salaran area of SE Saqqez, Kurdistan, Iran  

Science.gov (United States)

The Hassan Salarn area is located 20km to southeast of Saqqez city in Kurdistan Province, western Iran. In this area there are two distinct granitic rock suites consisting A-type and I-type granites and also mylonitic granites. These A-type and I-type granites have various petrological and geochemical characteristics. They also have different origins and petrogenesis. A-type granitoids comprise alkali feldspar granite, syenogranite and quartz alkali feldspar syenite, whereas I-type granitoids are composed of monzogranite, granodiorite and tonalite. Geochemically, A-type granitoids are peralkaline and acmite-normative but I-type granitoids are subalkaline (calc-alkaline), metaluminous and diopside-normative. A-type granitoids are also ferroan alkali and ferroan alkali-calcic whereas I-type granitoids are magnesian and calcic. A-type granitoids resemble to within plate granites and post-orogenic granites whereas I-type granitoids resemble to volcanic arc granites. A-type granitoids contain higher concentrations of alkalies, Zr, Rb, Nb, Y, Th, Ce, high FeO/MgO ratios and lower concentrations of Mg, Ca and Sr, resembling post-orogenic A-type granites. It is possible that heat from a mantle-derived magma which intruded into the lower crust, and/or rapid crustal extension have been essential generation of approriate melts producing A-type granitoids. Thus we can conclude that A-type granitoids were generated from a mixed mantle-crust source. Negative Nb anomalies and low contents of Ti and P probably indicate a subduction-related origin for protolith of I-type granitoids. Negative Nb anomalies and enrichment in Ce relative to its adjacent elements can be related to involvement of continental crust in magmatic processes. I-type granitoids are also enriched in Rb, Ba, K, Th, Ce and depleted in Nb, Zr and Y, indicating that they have had interacted with crust. I-type granitoids may result from contamination of mantle-derived magmas by continental crust during a subduction event. The mylonitic granites are elongated masses with a NE-SW trend and their contacts with the A-type and I-type granitoids are fault contact. Hand specimens have a layered appearance with green bands made from chlorite and epidote and grey to white bands with quartz and feldspar. These rocks contain plagioclase, quartz and orthoclase under the microscope. Also fine-grained minerals such as quartz, sericite, epidote, chlorite and opaque minerals make the groundmass wrapping the porphyroclasts. Pressure shadows around porphyroclasts of plagioclase and quartz and crystallization of fine-grained quartz and sericite in these places along with intense alteration of plagioclase to epidote and sericite, existence of quartz with different sizes, andaluse extinction in quartz crystals, and elongation of chlorites, resulted from dynamic recrystallisation of biotites all indicate effect of stresses on the rocks. Considering the similar mineralogical composition of the mylonitic rocks with I-type granitoid, it could be concluded that the granodioritic magma, after intrusion and solidification, is changed to mylonite in a shear zone due to tectonical forces.

Abdullah, Fakhraddin Mohammad; Saeed Ahmad, Sheler

2014-05-01

297

The fluid evolution of a proterozoic high-level anorogenic granite from the Gåsborn area, West Bergslagen, central Sweden  

Science.gov (United States)

The Proterozoic high-level anorogenic (A-type) Ostra Höjden granite and associated hydrothermal veins and skarns from the Gåsborn area, W. Bergslagen, central Sweden, contain aqueous, CO 2-rich (gaseous) and mixed aqueous-gaseous fluid inclusions. The oldest aqueous inclusions are highly saline (32-40 wt.% NaCl eq.). The oldest gaseous inclusions are CO 2-rich with, locally, minor amounts of N 2 and CH 4. Aqueous inclusions become less saline and CO 2-rich inclusions become less dense and loose their N 2 and CH 4 content, going from older to younger generations. Large quantities of mixed aqueous-gaseous inclusions only occur in hydrothermal veins in marble. ? 13C values of around - 1.6% of CO 2 in these inclusions suggest that they were formed by heterogeneous trapping of an aqueous fluid and CO 2 was derived from the surrounding marble. Many of the oldest aqueous and mixed aqueous-gaseous inclusins are decrepitated and surrounded by trails and fields of less dense, younger inclusions formed during and after decrepitation. The maximal fluid pressure and temperature are estimated at about 4 kbar and approximately 560°C, respectively. The lithostatic pressure is estimated at < 1.0 kbar, indicating that hydrothermal vein formation resulted from hydrostatic overpressuring of fluids expelled from the cooling granite.

Damman, Arend H.

1989-03-01

298

GRANITE- A steroscopic imaging Chernkov telescope system  

International Nuclear Information System (INIS)

A second 10 meter class imaging telescope was constructed on Mt. Hopkins, Arizona, the site of the original 10 meter Whipple Cherenkov telescope. The twin telescope system with a 140 meter base line will allow both a reduction in the energy threshold and an improvement in the rejection of the hardonic background. The new telescope started operation in December 1991. With the final completion of the first installation stage (GRANITE I) during spring 92, it is now operating simultaneously with the orginal reflector. We describe in this paper design and construction of the new instrument and demonstrate the capability of the experiment to record coincident events

299

Innovative Method for Saltwater Intrusion Control  

Directory of Open Access Journals (Sweden)

Full Text Available Salt water intrusion is the migration of saltwater into freshwater aquifers under the influence of groundwater development (Freeze and Cherry, 1979. The most detrimental effect that ground water depletion causes lowering of water table. Another problem due to saltwater intrusion is changing saltwater freshwater interface. Methods for controlling intrusion vary widely depending on the source of the saline water, the extent of intrusion, local geology, water use and economic factors. The proposed methodology to control saltwater intrusion is (ADR Abstraction, Desalination and Recharge. The proposed methodology interplays between the major parameters of the system to control saltwater intrusion. These parameters include the soil/aquifer properties, the well locations, the well depths, the rates and the relation between the abstraction and recharge rates which depends on the recovery rate and the salinity degree. It is capable of completely preventing saltwater intrusion because it increases the volume of fresh groundwater and decreases the volume of saltwater, while considering economical aspects, environmental impact and sustainable development of water resources.

Z. Payal

2014-02-01

300

Sm/Nd and whole rock geochemistry characterization of the Serra Branca granite: evidence of Archean crust in the Pajeu Paraiba fold belt  

International Nuclear Information System (INIS)

This work presents and discusses the geochemical and Samarium-Neodymium (SM/Nd) isotopic data for the Serra Branca granite. The Serra Branca granite constitutes one among several brasiliano (=Pan African) intrusions of the transversal zone of the Borborema Tectonica Province, northeastern of Brazil. It is intruded into gneisses and migmatites from the Alto Pajeu Terrain (TAP). The Alto Pajeu Terrain comprises mainly metasediments with minor volcanic contributions and the brasiliano magmatism is restrict to the TAP. After presenting the geological and petrographical considerations, the study shows the Sm-Nd data and concludes that the geochemical and Sm-Nd isotopic signatures of the Serra Branca complex point to a magma generation in the contact zone between an Archean and a Tranzamazonian crust, during decompression, which followed the Brasiliano collisional event

301

Advanced technologies for perimeter intrusion detection sensors  

Energy Technology Data Exchange (ETDEWEB)

The development of integrated circuit fabrication techniques and the resulting devices have contributed more to the advancement of exterior intrusion detectors and alarm assessment devices than any other technology. The availability of this technology has led to the improvements in and further development of smaller more powerful computers, microprocessors, solid state memories, solid state cameras, thermal imagers, low-power lasers, and shorter pulse width and higher frequency electronic circuitry. This paper presents information on planning a perimeter intrusion detection system, identifies the site characteristics that affect its performance, and describes improvements to perimeter intrusion detection sensors and assessment devices that have been achieved by using integrated circuit technology.

Williams, J.D.

1995-03-01

302

Intrusion detection using deep belief network  

International Nuclear Information System (INIS)

This paper proposes an intrusion detection technique based on DBN (Deep Belief Network) to classify four intrusion classes and one normal class using KDD-99 dataset. The proposed technique is based on two phases: in first phase it removes the class imbalance problem and in the next, it applies DBN followed by FFNN (Feed-Forward Neural Network) to build a prediction model. The obtained results are compared with those given in (9). The prediction accuracy of our model shows promising results on both intrusion and normal patterns. (author)

303

Age and origin of coeval TTG, I- and S-type granites in the Famatinian belt of NW Argentina  

International Nuclear Information System (INIS)

Full text: Located on the Palaeozoic Pacific margin of Gondwana, at the opposite extreme to the Lachlan Fold Belt, the Sierras Pampeanas of central and NW Argentina also constitute a large granitic province displaying the coeval concurrence of I and S-type magmas. The Famatinian magmatic belt consists mostly of granitoids emplaced in Early Ordovician times, after Cambrian accretion of the Pampean terrane and before the Late Ordovician/Silurian accretion of the Precordillera terrane. New SHRIMP U-Pb zircon ages, isotope and geochemical data are used to interpret the petrogenesis of this belt. Three types of granitoid are recognized in the Famatinian belt, based on lithology and geochemical data. These are (a) a minor trondhjemite-tonalite-granodiorite (TTG) group, which occurs only in the Pampean foreland, (b) a metaluminous I-type gabbromonzogranite suite, and (c) S-type granites, which occur both as small cordieritic intrusions associated with l-type granodiorites and as large batholithic masses. Twelve new SHRIMP U-Pb zircon ages establish the contemporaneity of all three types in Early Ordovician times (mainly 470-490 Ma ago). Sr- and Nd-isotopic data suggest that, apart from some TTG plutons with asthenospheric characteristics, the remaining magmas were derived from a Proterozoic crust-lithospheric mantle section (Nd model ages of 1500-1700 Ma). Granulite xenoliths in Cretaceous alkalic rocks that have been described by other authors may represent samples of this her authors may represent samples of this source region. Trace element modelling suggests that the TTG and I-type gabbros originated by variable melting of a lithospheric gabbroid source at 10-12 kbar and ca. 5 kbar, respectively. The voluminous intermediate and acidic I-types, which show a trend to slightly more evolved isotopic signatures than the inferred source, probably represent hybridization of the most primitive magmas with lower and middle crustal melts. The highly peraluminous S-type granites have similar isotopic and inherited zircon patterns to Cambrian supracrustal metasedimentary rocks deposited in the Pampean cycle, and were derived from them by local anatexis. Other major components of the S-type batholiths, including porphyritic biotite granites, probably involved melting of deeper crust and mixing with the l-type magmas, leading to an isotopic and geochemical continuum. This model is similar to others that have been advanced for the I- and S-type granites of the Lachlan Fold Belt of Australia and the Hercynian granites of Spain, but we argue that in the Famatinian belt at least no juvenile mantle source was involved. Copyright (1999) Geological Society of Australia

304

Petrogenesis of Tin-bearing Granites from Ervedosa, Northern Portugal: The Importance of Magmatic Processes  

OpenAIRE

Three Hercynian highly peraluminous tin-bearing granites define a sequence ranging from muscovite-biotite granite to muscovite granite. Tin-bearing quartz veins are genetically related to this sequence. Variation diagrams of most major and trace elements of granites, biotite and muscovite show fractionation trends. Least squares analysis of major elements and modelling of trace elements indicate that the muscovite-biotite granite M2 and the muscovite granite M3 were derived from the slightly ...

Gomes, M. E. P.; Neiva, A. M. R.

2002-01-01

305

The Younger Dryas age of the Salpausselkä moraines in Finland  

Directory of Open Access Journals (Sweden)

Full Text Available The late-glacial Younger Dryas Stadial, as defined over seventy years ago in Denmark, was compared with the withdrawal of the Scandinavian ice sheet and correlated in Finland in 1951 with the formation of the Salpausselkä moraines. Since then a great number of studies of Younger Dryas has eventually led to its definition in the Event Stratigraphy for the North Atlantic region, based on the oxygen isotope stratigraphy in the Greenland ice-core NGRIP. The age of the Younger Dryas / Preboreal boundary, the beginning of the Holocene, is in this stratigraphy dated at 11 653 yr. BP, an age close to the age deter-mined for the drainage of the Baltic Ice Lake and the beginning of the rapid retreat of the ice margin from Salpausselkä II in Finland and the corresponding Billingen moraine in Sweden. This leads to the conclusion that the Salpausselkä moraines Ss I and Ss II were formed during Younger Dryas, according to the revised varve chronology between c. 12 260 and c. 11 600 yr. BP. The third Salpausselkä, Ss III, was according to this dating formed in early Holocene. After the 1950s, when the Salpausselkä moraines were dated as having been formed during the Younger Dryas Stadial, the ages of the boundaries of Younger Dryas changed as a result of revisions of the time scales of varved clays and the use of radiocarbon ages and their calibrations. As a result of these changes the age of the two main Salpausselkä moraines, Ss I and Ss II, is older than assumed 60 years ago on the basis of the varve chronology.

Joakim Donner

2010-12-01

306

The 'Granite' collegial mission of dialogue. Report  

International Nuclear Information System (INIS)

The aim of the 'Granite' collegial mission of dialogue is to inform the French authorities, associations and population about the project of construction of an underground laboratory for the study of the disposal of high level and long-life radioactive wastes in a granitic environment. The aim of the dialogue was not to select a site but to collect the public reactions and advices about such a project. However, such a dialogue has partially failed because of a misunderstanding of the population about the aims of the mission. However, the mission has collected many point of views and questions which are developed in this report. The first and second chapters recall the process of the mission and its progress, while a third chapter stresses on the questions asked by the public and which concern the fear of nuclear wastes and the incompatibility between the disposal of wastes and the socio-economical development of the region concerned. Thanks to the lessons drawn from this experience, the mission has formulated some recommendations (chapter 4) concerning the need for a better information of the population about any topic in relation with the radioactive wastes. Some complementary information is provided in appendixes. (J.S.)

307

Static fatigue of granite at 2000C  

International Nuclear Information System (INIS)

Cylinders of Barre and Westerly granites have been compressed to failure in static fatigue tests under dry and wet conditions at 1 Kb confining pressure and temperatures of 240 and 200 0C. The effect of increasing temperature and water content is, as expected, to weaken the rocks appreciably and to reduce the time to failure, at constant stress, by about two orders of magnitude. The activation energy estimated for dry Barre granite deformed in temperature range 240 to 200 0C is 10.2 Kcal/mol which seems reasonable and is consistent with other work at higher temperatures. Extrapolation of the static fatique equations obtained for specimens deformed at 200 0C, both wet and dry, to 108 years yields maximum stress differences near 3 Kb. While such extrapolations may be reasonable for intact material over time-spans of interest to national concerns, the stresses obtained seem unreasonably high for tectonic deformations. The discrepancy probably results from the very short durations of the tests which do not permit effective operation, at these low temperatures, of the several thermally-activated weakening effects of H2O on silicates

308

Aqueous phase transport through granitic rocks  

International Nuclear Information System (INIS)

Using Scottish granites of UK origin it has been established that : (1) pore connectivity exists over metre distances and does not vary significantly with distance. (2) The formation factor may show an increase by a factor of approx. 2 for thin samples (approx. 1 cm). Since diffusion samples are of this order of thickness, laboratory measurements may be overestimating the diffusion coefficient appropriate for use in migration model calculations by a factor of approx. 2. (3) The effect of confining pressures up to approx. 16 MPa is to reduce diffusion coefficients by 50 to 60%. This implies that diffusion coefficients appropriate to granite at depths of approx. 500 m are approximately a factor of two lower than those obtained in the laboratory. (4) Diffusion rates through weathered fissure surfaces can be significantly greater (up to approx. 200 times) than through 'good' rock and are strongly dependent on the severity of the weathering. No evidence for pore blocking by weathering products was found. (5) Latex colloids having a diameter of 0.312 ?m neither cause pore blocking nor do they penetrate the pore structure. (author)

309

Uranium in the Carnmenellis granite, Cornwall, England  

International Nuclear Information System (INIS)

Samples from a 30 meter core from the Rosemanowas quarry in the Carnmenellis granite in Cornwall, England were analyzed by induced fission track detection, delayed neutron detection, backscattered electron imaging in a SEM, and energy dispersive x-ray spectrometry. Uranium occurs mainly in: (1) primary accessory minerals; (2) alteration and replacement phases, and (3) microcrack-sealing phases. Zircon, monazite, and apatite are common uraniferous primary accessory minerals. Uraniferous alteration phases include hematite, rutile and pyrolusite. Hematite is a common uraniferous replacement phase. Most sealed microcracks contain uranium. Hematite and pyrolusite are ubiquitous uraniferous crack-sealing phases. Autunite and churchite are occasional uraniferous crack-sealing phases. Whole rock uranium concentrations are extremely variable. High uranium contents result from high percentages of uraniferous primary accessory phases and/or rutile. Hydrothermal activity, such as hematization, can result in depleted whole rock uranium concentrations. Results of this study indicate that uranium and light rare earth elements have been mobilized and redistributed in this section of the Carnmenellis granite by postmagmatic processes. 28 refs., 13 figs. 2 tabs

310

Understanding death and grief for children three and younger.  

Science.gov (United States)

Although the average toddler's cognitive skills may be limited, children three and younger have emotional responses to the death of someone they have known. Theories and research indicate that children's individual characteristics, their developmental stage including cognitive level, and their environmental and familial experiences must be considered to understand their grief. Myriad misconceptions and euphemisms can complicate and exacerbate children's grief. The authors address the possibilities for age-appropriate, theory-based interventions by clinicians and parents to effectively assist children three and younger in their grief work. PMID:8256145

Norris-Shortle, C; Young, P A; Williams, M A

1993-11-01

311

The Serra do Carambei Granite - PR and the uraniferous anomalism  

International Nuclear Information System (INIS)

The Serra do Carambei Granite forms a pluton relatively homogeneous, covering about 33 km2, cropping out as an elongate retangular body trending NE-SW, being emplaced in the Cunhaporanga Granitoid Complex. Its characteristics indicates a kind of hololeucocratic granite, equigranular, medium to coarse-grained, consisting predominantly of microperthitic alkali-feldspar, quartz and a small amount of biotite (less than 1%), thus being classified as an alaskite. Chemical data allows a classification in the group of granite with high contents of silica (74-76% Wt. SiO2), dominantly alkaline chemism and hypersolvus character, derived from a parental magma under saturated in water with distinguished features of granitoids from the magnetite series and types I and A granites. The pluton shows important chemical variations due to weathering processes. However detailed chemical studies reveal the presence of anomalous concentrations of trace elements such as U, Sn, Nb, Y, Zr, the Serra do Carambei Granite lacks economically important mineralizations because of the absence of well-developed tardi/pos-magmatic processes that could concentrate them. The SW side of the granite is cut by leucocratic rhyolite dykes that show some radiometric anomalies. These rocks, which are highly diferentiated, were emplaced contemporaneously to the Serra do Carambei Granite. Although petrographic and chronological similarities are found between the uraniferous alaskite of Roessing (Namibia) and the Serra do Carambei Granite anyhow it was not possible to establish any lateral continuity with the uranifeous Pan-African Province. (Author)

312

Autonomous Rule Creation for Intrusion Detection  

Energy Technology Data Exchange (ETDEWEB)

Many computational intelligence techniques for anomaly based network intrusion detection can be found in literature. Translating a newly discovered intrusion recognition criteria into a distributable rule can be a human intensive effort. This paper explores a multi-modal genetic algorithm solution for autonomous rule creation. This algorithm focuses on the process of creating rules once an intrusion has been identified, rather than the evolution of rules to provide a solution for intrusion detection. The algorithm was demonstrated on anomalous ICMP network packets (input) and Snort rules (output of the algorithm). Output rules were sorted according to a fitness value and any duplicates were removed. The experimental results on ten test cases demonstrated a 100 percent rule alert rate. Out of 33,804 test packets 3 produced false positives. Each test case produced a minimum of three rule variations that could be used as candidates for a production system.

Todd Vollmer; Jim Alves-Foss; Milos Manic

2011-04-01

313

STATISTICAL TECHNIQUES IN ANOMALY INTRUSION DETECTION SYSTEM  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, we analyze an anomaly based intrusion detection system (IDS for outlier detection in hardware profile using statistical techniques: Chi-square distribution, Gaussian mixture distribution and Principal component analysis. Anomaly detection based methods can detect new intrusions but they suffer from false alarms. Host based Intrusion Detection Systems (HIDSs use anomaly detection to identify malicious attacks i.e. intrusion. The features are shown by large set of dimensions and the system becomes extremely slow during processing this huge amount of data (especially, host based. We show the comparative results using three different approaches: Principal Component Analysis (PCA, Chi-square distribution and cluster with Gaussian mixture distribution. We get good results using these techniques.

Hari Om

2012-11-01

314

Prevention and analysis of hacker's intrusion  

International Nuclear Information System (INIS)

The author analyzes the behavior characteristics and relevant technologies about the hacker's intrusion, and gives some corresponding solutions pertinently. To the recent events about hackers, the author gives detailed introduction and puts forward the relevant advice and valuable consideration

315

Petrogenesis of syntectonic granites emplaced at the transition from thrusting to transcurrent tectonics in post-collisional setting: Whole-rock and Sr-Nd-Pb isotope geochemistry in the Neoproterozoic Quatro Ilhas and Mariscal Granites, Southern Brazil  

Science.gov (United States)

The Neoproterozoic post-collisional period in southern Brazil (650-580 Ma) is characterized by substantial volumes of magma emplaced along the active shear zones that compose the Southern Brazilian Shear Belt. The early-phase syntectonic magmatism (630-610 Ma) is represented by the porphyritic, high-K, metaluminous to peraluminous Quatro Ilhas Granitoids and the younger heterogranular, slightly peraluminous Mariscal Granite. Quatro Ilhas Granitoids include three main petrographic varieties (muscovite-biotite granodiorite — mbg; biotite monzogranite — bmz; and leucogranite — lcg) that, although sharing some significant geochemical characteristics, are not strictly comagmatic, as shown by chemical and Sr-Nd-Pb isotope data. The most primitive muscovite-biotite granodiorite was produced by contamination of more mafic melts (possibly with some mantle component) with peraluminous crustal melts; the biotite monzogranite, although more felsic, has higher Ca, MgO, TiO2 and Ba, and lower K2O, FeOt, Sr and Rb contents, possibly reflecting some mixing with coeval mafic magmas of tholeiitic affinity; the leucogranite may be derived from pure crustal melts. The Mariscal Granite is formed by two main granite types which occur intimately associated in the same pluton, one with higher K (5-6.5 wt.% K2O) high Rb and lower CaO, Na2O, Ba and Zr as compared to the other (3-5 wt.% of K2O). The two Mariscal Granite varieties have compositional correspondence with fine-grained granites (fgg) that occur as tabular bodies which intruded the Quatro Ilhas Granoitoids before they were fully crystallized, and are inferred to correspond to the Mariscal Granite feeders, an interpretation that is reinforced by similar U-Pb zircon crystallization ages. The initial evolution of the post-collisional magmatism, marked by the emplacement of the Quatro Ilhas Granitoids varieties, activated sources that produced mantle and crustal magmas whose emplacement was controlled both by flat-lying and transcurrent structures. The transition from thrust to transcurrent-related tectonics coincides with the increase in the proportion of crustal-derived melts. The transcurrent tectonics seems to have played an essential role in the generation of mantle-derived magmas and may have facilitated their interaction with crustal melts which seem to be to a large extent the products of reworking of orthogneiss protoliths.

Florisbal, Luana Moreira; Bitencourt, Maria de Fátima; Janasi, Valdecir de Assis; Nardi, Lauro Valentim Stoll; Heaman, Larry M.

2012-11-01

316

Using Commodity Coprocessors for Host Intrusion Detection  

OpenAIRE

The ever-rising importance of communication services and devices emphasizes the significance of intrusion detection. Besides general network attacks, private hosts in particular are within the focus of cyber criminals. Private data theft and the integration of individual hosts into large-scale botnets are two common purposes successfully subverted systems are used for. In order to detect any attack, intrusion detection mechanisms need to probe the data in question. Therefore, the acquisition ...

Seger, Mark M.

2012-01-01

317

Network Intrusion Detection using Support Vector Regression  

OpenAIRE

Data Mining is the use of algorithms to extract the information and patterns derived by the knowledge discovery in databases process. Classification maps data into predefined groups or classes. It is often referred to as supervised learning because the classes are determined before examining the data. This paper addresses using ensemble approach of Support Vector Regression for intrusion detection. Due to increasing incidents of cyber attacks, building effective intrusion detection systems (I...

Govindarajan Muthukumarasamy

2011-01-01

318

Unsupervised Genetic Algorithm Deployed for Intrusion Detection  

OpenAIRE

This paper represents the first step in an on-going work for designing an unsupervised method based on genetic algorithm for intrusion detection. Its main role in a broader system is to notify of an unusual traffic and in that way provide the possibility of detecting unknown attacks. Most of the machinelearning techniques deployed for intrusion detection are supervised as these techniques are generally more accurate, but this implies the need of labeling the data for training and testing whic...

Bankovic, Zorana; Bojanic, Slobodan; Nieto-taladriz Garci?a, Octavio; Badii, Atta

2008-01-01

319

Adaptive Genetic Algorithm Model for Intrusion Detection  

OpenAIRE

Intrusion detection systems are intelligent systems designed to identify and prevent the misuse of computer networks and systems. Various approaches to Intrusion Detection are currently being used, but they are relatively ineffective. Thus the emerging network security systems need be part of the life system and this ispossible only by embedding knowledge into the network. The Adaptive Genetic Algorithm Model - IDS comprising of K-Means clustering Algorithm, Genetic Algorithm and Neural Netwo...

Anil Kumar, K. S.; Nanda Mohan, Dr V.

2012-01-01

320

Multilayer Statistical Intrusion Detection in Wireless Networks  

OpenAIRE

The rapid proliferation of mobile applications and services has introduced new vulnerabilities that do not exist in fixed wired networks. Traditional security mechanisms, such as access control and encryption, turn out to be inefficient in modern wireless networks. Given the shortcomings of the protection mechanisms, an important research focuses in intrusion detection systems (IDSs). This paper proposes a multilayer statistical intrusion detection framework for wireless networks. The archite...

Noureddine Boudriga; Amel Meddeb-Makhlouf; Mohamed Hamdi

2008-01-01

321

Adaptive Alert Throttling for Intrusion Detection Systems  

OpenAIRE

Each time that an intrusion detection system raises an alert it must make some attempt to communicate the information to an operator. This communication channel can easily become the target of a denial of service attack because, like all communication channels, it has a fixed capacity. If this channel can become overwhelmed with bogus data, an attacker can quickly achieve complete neutralisation of intrusion detection capability. Although these types of attack are very hard ...

Tedesco, Gianni; Aickelin, Uwe

2013-01-01

322

An Architecture of Hybrid Intrusion Detection System  

OpenAIRE

Intrusion Detection System (IDS) is renowned and widely-deployed security tool to detect attacks and malicious activities in information system. It is an essential element of any contemporary information system. There are mainly two techniques for intrusion detection: i) signature-based (misuse) detection and ii) anomaly-based detection technique. Both the techniques have their advantages and disadvantages. This paper presents research from an ongoing study on the use of features of both the ...

Patel, Kanubhai K.; Buddhadev, Bharat V.

2012-01-01

323

A Comprehensive Study in Data Mining Frameworks for Intrusion Detection  

OpenAIRE

Intrusions are the activities that violate the security policy of system. Intrusion Detection is the process used to identify intrusions. Network security is to be considered as a major issue in recent years, since the computer network keeps on expanding every day. An Intrusion Detection System (IDS) is a system for detecting intrusions and reporting to the authority or to the network administration. Data mining techniques have been successfully applied in many fields like Network Management,...

R Venkatesan, R. Ganesan

2012-01-01

324

Java-Based Intrusion Detection System in a Wired Network  

OpenAIRE

Intrusion Detection has become an integral part of the information security process. The cost involved in protecting network resources is often neglected when compared with the actual cost of a successful intrusion, which strengthens the need to develop more powerful intrusion detection systems. Many existing systems for intrusion detection are developed in C, Objective-C, Tcl, C++ programming languages. In this paper, we design and develop a network intrusion detection system using Java prog...

Ezin, Euge?ne C.; Hervé Akakpo Djihountry

2011-01-01

325

Multilayer Intrusion Detection System In Web Application Based Services  

OpenAIRE

Web based services having a data transfer from different layer. Web services separate layer for the data transfer and the process is difficult in the service. Service transferring data is having intrusion from the user interaction in web based services to detect the intrusion in alert basis and detect the intrusion in both online and offline. In offline alert data previously having attack basis it can be rectified. The online alert system data having the intrusion collect the intrusion in buf...

Narmadha.S; Deepak Lakshmi Narashima

2013-01-01

326

Petrogenesis of the mineralized granitic intrusion near Los Santos, Western Spain, and remote sensing and data integration as a tool in regional exploration for granite related mineralization  

OpenAIRE

Ground based metal exploration is labour intensive and thus expensive. Data acquisition by satellite and aircraft, and subsequent image processing seem to offer a cheaper and attractive strategy to replace some of this effort, notably in the screening phase of a new project. However, realizing this promise requires considerably more than an image processing system and some satellite data. A vital component is a calibration area with known mineralization where the geology is suffic...

Goossens, M. A.

1992-01-01

327

Chemical characteristics of zircon from A-type granites and comparison to zircon of S-type granites.  

Czech Academy of Sciences Publication Activity Database

1192/195, April (2014), s. 208-225. ISSN 0024-4937 Institutional support: RVO:67985831 Keywords : zircon * A-type granite s * S-type granite s * Wiborg batholith * Brazil * Krušné hory/Erzgebirge Subject RIV: DD - Geochemistry Impact factor: 3.654, year: 2013

Breiter, Karel; Lamarão, C. N.; Krás Borges, R. M.; Dall'Agnol, R.

328

Network Intrusion Detection using Support Vector Regression  

Directory of Open Access Journals (Sweden)

Full Text Available Data Mining is the use of algorithms to extract the information and patterns derived by the knowledge discovery in databases process. Classification maps data into predefined groups or classes. It is often referred to as supervised learning because the classes are determined before examining the data. This paper addresses using ensemble approach of Support Vector Regression for intrusion detection. Due to increasing incidents of cyber attacks, building effective intrusion detection systems (IDS are essential for protecting information systems security, and yet it remains an elusive goal and a great challenge. The feasibility and the benefits of the proposed approach are demonstrated by means of data mining problem: Network Intrusion Detection. Intrusion detection systems help network administrators prepare for and deal with network security attacks. These systems collect information from a variety of systems and network sources, and analyze them for signs of intrusion and misuse.  We show that proposed ensemble of Support Vector Regression is superior to individual approach for intrusion detection in terms of classification rate.

Govindarajan Muthukumarasamy

2011-04-01

329

A system for distributed intrusion detection  

Energy Technology Data Exchange (ETDEWEB)

The study of providing security in computer networks is a rapidly growing area of interest because the network is the medium over which most attacks or intrusions on computer systems are launched. One approach to solving this problem is the intrusion-detection concept, whose basic premise is that not only abandoning the existing and huge infrastructure of possibly-insecure computer and network systems is impossible, but also replacing them by totally-secure systems may not be feasible or cost effective. Previous work on intrusion-detection systems were performed on stand-alone hosts and on a broadcast local area network (LAN) environment. The focus of our present research is to extend our network intrusion-detection concept from the LAN environment to arbitarily wider areas with the network topology being arbitrary as well. The generalized distributed environment is heterogeneous, i.e., the network nodes can be hosts or servers from different vendors, or some of them could be LAN managers, like our previous work, a network security monitor (NSM), as well. The proposed architecture for this distributed intrusion-detection system consists of the following components: a host manager in each host; a LAN manager for monitoring each LAN in the system; and a central manager which is placed at a single secure location and which receives reports from various host and LAN managers to process these reports, correlate them, and detect intrusions. 11 refs., 2 figs.

Snapp, S.R.; Brentano, J.; Dias, G.V.; Goan, T.L.; Heberlein, L.T.; Ho, Che-Lin; Levitt, K.N.; Mukherjee, B. (California Univ., Davis, CA (USA). Div. of Computer Science); Grance, T. (Air Force Cryptologic Support Center, San Antonio, TX (USA)); Mansur, D.L.; Pon, K.L. (Lawrence Livermore National Lab., CA (USA)); Smaha, S.E. (Haystack Labs., Inc., Austin, TX (USA))

1991-01-01

330

Exploring Interhemispheric Collaboration in Older Compared to Younger Adults  

Science.gov (United States)

Physical and Name Identity letter-matching tasks were used to explore differences in interhemispheric collaboration in younger and older adults. To determine whether other factors might also be related to across/within-hemisphere processing or visual field asymmetries, neuropsychological tests measuring frontal/executive functioning were…

Cherry, Barbara J.; Yamashiro, Mariana; Anderson, Erin; Barrett, Christopher; Adamson, Maheen M.; Hellige, Joseph B.

2010-01-01

331

Atomoxetine Treatment for ADHD: Younger Adults Compared with Older Adults  

Science.gov (United States)

Objective: Atomoxetine is a nonstimulant medication for treating child, adolescent, and adult ADHD. This meta-analysis compared the effects in younger and older adults. Method: A post hoc analysis was conducted using data from two double-blind, placebo-controlled clinical trials. Data from patients aged 18-25 years were compared with data from…

Durell, Todd; Adler, Lenard; Wilens, Timothy; Paczkowski, Martin; Schuh, Kory

2010-01-01

332

Older and Younger Workers: The Equalling Effects of Health  

Science.gov (United States)

Purpose: The purpose of this paper is to consider the statistical evidence on the effects that ill health has on labour market participation and opportunities for younger and older workers in the East Midlands (UK). Design/methodology/approach: A statistical analysis of Labour Force Survey data was undertaken to demonstrate that health issues…

Beck, Vanessa; Quinn, Martin

2012-01-01

333

SHRIMP U/Pb zircon ages of acid volcanic rocks in the Chitradurga and Sandur groups, and granites adjacent to the Sandur Schist belt, Karnataka  

International Nuclear Information System (INIS)

Sensitive high-resolution ion microprobe (SHRIMP) U/Pb dating of zircon grains from a schistose acid volcanic rock from the Daginkatte formation in the Chitradurga group of the late Archaean Dharwar supergroup in western Karnataka has yielded a precise concordant age of 2614 ± 8 Ma which indicates the time of melt crystallisation. In contrast, zircons from similar schistose acid volcanic rocks in the Vibhuti Gudda formation of the Sandur group in the Sandur schist belt of eastern Karnataka yielded less precise concordia intercept ages of 2658 ± 14 and 2691 ± 18 Ma. Zircons from high-strain grey gneisses which appears to be the oldest recognizable component of the late Archaean granite complex adjacent to the Sandur schist belt have an imprecise age of 2719 ± 40 Ma. Zircons from the youngest recognizable granite adjacent to the belt have also yielded an imprecise, but younger, age of 2570 ± 62 Ma. The ages show that granite emplacement and deformation adjacent to the Sandur schist belt took place in a period of c.150 Ma. The imprecise ages of zircon in the acid volcanic rocks in the Sandur Group and the adjacent granites are related to Neoproterozoic loss of lead which may have been an effect of either weathering or a regional thermal event. We favour the latter in the light of the record of Pan-African thermal effects in the east and south of southern Peninsular India. (author). 33 refs., 6 figs., 2 tabs

334

Zircon U-Pb geochronology and elemental and Sr-Nd-Hf isotopic geochemistry of the Daocheng granitic pluton from the Yidun Arc, SW China  

Science.gov (United States)

The Garze-Litang suture zone, located in the eastern part of the Tethyan tectonic domain, is notable for widespread Late Triassic granitic plutons, which are genetically associated with the evolution of the Paleo-Tethys Ocean. The Daocheng granitic pluton in the eastern Yidun Arc, SW China, is located in the middle of the Garze-Litang suture zone and has an outcrop area of ˜2800 km2. In the present study, we report zircon U-Pb ages and elemental and Sr-Nd-Hf isotopic data for the Daocheng granitic intrusion. Secondary ion mass spectrometry and laser ablation inductively coupled plasma mass spectrometry U-Pb analyses on zircons yield consistent ages of ca. 216 Ma for three samples from the pluton. All the Daocheng granitic rocks are enriched in Si (SiO2 = 68.1-76.4%) and large-ion lithophile elements but depleted in high-field-strength elements (e.g., Nb, Ta, and Ti). Mineralogical and geochemical features indicate that these are high-K and calc-alkaline and I-type granites. They are characterized by relatively variable initial 87Sr/86Sr ratios (0.7059-0.7102), negative ?Nd(t) values (-5.7 to -7.8), wide-ranging ?Hf(t) values (-9.8 to +3.4), and two-stage Hf model ages of 1.04 to 1.88 Ga. These isotopic signatures indicate that the source for the Daocheng granite was probably derived from partial melting of a Late Paleoproterozoic to Early Mesoproterozoic mafic-intermediate lower crust with a variably minor addition (<20%) of depleted mantle-derived magma. The parental magma thereafter underwent extensive fractional crystallization of ferromagnesian minerals, plagioclase, apatite, ilmenite, and rutile during emplacement, under temperatures from 785 °C to 839 °C. In combination with previous studies on synchronous magmatism in the Yidun Arc, we propose that the Daocheng granite was generated in a syncollisional tectonic setting. The westward subduction and closure of the Garze-Litang paleo-ocean triggered the underplating of large-scale mantle-derived magma and provided heat for the anatexis of the lower crust. Hybrid melts including minor depleted mantle-derived magma and lower crustal magma were then generated; these thereafter were continuously injected into a shallow-level chamber and gave rise to the Daocheng granite.

He, De-Feng; Zhu, Wei-Guang; Zhong, Hong; Ren, Tao; Bai, Zhong-Jie; Fan, Hong-Peng

2013-05-01

335

The Phalaborwa Syenite Intrusions along the West-Central Boundary of the Kruger National Park  

Directory of Open Access Journals (Sweden)

Full Text Available The geology of the Phalaborwa Complex is described and emphasis placed on the distribution of the large number of syenite intrusions. The petrography of the different textural types of syenites is discussed and it is shown that porphyritic, granular, gneissic and hypidiomorphic syenites are present. The petrography shows that the deformation textures, which are present in some of the syenites, may have formed during the emplacement of syenitic magmas which contained a high concentration of crystals. The geochemistry of the syenites is discussed and it is shown that they were not derived from an alkali basaltic magma through fractional crystallisation, but that they may rather represent alkali basaltic magmas which were contaminated by granitic material. The mode of emplacement of the Phalaborwa Complex is discussed and the relationship between the pyroxenites is explained.

C. Frick

1986-12-01

336

IRETHERM: The geothermal energy potential of Irish radiothermal granites  

Science.gov (United States)

The IRETHERM project is developing a strategic understanding of Ireland's deep geothermal energy potential through integrated modelling of new and existing geophysical and geological data. One aspect of IRETHERM's research focuses on Ireland's radiothermal granites, where increased concentrations of radioelements provide elevated heat-production (HP), surface heat-flow (SHF) and subsurface temperatures. An understanding of the contribution of granites to the thermal field of Ireland is important to assessing the geothermal energy potential of this low-enthalpy setting. This study focuses on the Galway granite in western Ireland, and the Leinster and the buried Kentstown granites in eastern Ireland. Shallow (geothermal project. These studies yielded HP = 2-3 ?Wm-3 and HF = 80 mWm-2 at the Sally Gap borehole in the Northern Units of the Leinster granite, to the SW of Dublin. In the Galway granite batholith, on the west coast of Ireland, the Costelloe-Murvey granite returned HP = 7 ?Wm-3 and HF = 77 mWm-2, measured at the Rossaveal borehole. The buried Kentstown granite, 35 km NW of Dublin, has an associated negative Bouguer anomaly and was intersected by two mineral exploration boreholes at depths of 660 m and 490 m. Heat production is measured at 2.4 ?Wm-3 in core samples taken from the weathered top 30 m of the granite. The core of this study consists of a program of magnetotelluric (MT) and audio-magnetotelluric (AMT) data acquisition across the three granite bodies, over three fieldwork seasons. MT and AMT data were collected at 59 locations along two profiles over the Leinster granite. Preliminary results show that the northern units of the Leinster granite (40 km SW of Dublin) extend to depths of 2-5 km. Preliminary results from the southern profile suggest a greater thickness of granite to a depth of 6-9 km beneath the Tullow pluton, 75 km SW of Dublin. Over the Galway granite, MT and AMT data have been collected at a total of 75 sites (33 consist of only AMT data acquisition, with both MT and AMT recorded at the remaining 42). Preliminary results show a deep resistor extending to depths of 15-20 km beneath the central block, with the resistive upper layer extending to depths of 3.5-7 km west of the Shannawona fault, a major structure that cuts the batholith. MT and AMT data acquired along a profile at 22 locations over the Kentstown granite suggests that this buried granite is at a depth of 400 m beneath the centre of the gravity anomaly. The MT and AMT data will be integrated with gravity and seismic refraction data (in the case of the Leinster granite) to identify deeply penetrating faults, which may provide conduits for hydrothermal fluids, and to produce a robust estimation of the volumetric extent of the granites, which is crucial in defining their geothermal energy potential. Thermal conductivity and geochemical data will be incorporated to constrain the heat contribution of granites to the Irish crust.

Farrell, Thomas; Jones, Alan; Muller, Mark; Feely, Martin; Brock, Andrew; Long, Mike; Waters, Tim

2014-05-01

337

On Younger Stakeholders and Decommissioning of Nuclear Facilities  

International Nuclear Information System (INIS)

In modern democratic countries, information sharing and effective and open communication concerning dismantling and decommissioning of of nuclear facilities as well as the management of nuclear waste are essential for the task to build the confidence required for any further development of nuclear energy. At the same time, it is often perceived that all decision making processes about nuclear energy policies are probably increasingly influenced by public opinion. Nuclear and radiation safety Authorities have a clear role in this regard to provide unbiased information on any health and safety related issues. In order to meet this need, it is necessary for Authorities and others to understand the values and opinions of the citizens, and especially the younger ones. They hold the key to the future at the same time as their perspective on these issues is the least understood. The need of greater public participation in decision making is becoming increasingly recognised the scientific as well as the political community. Many activities are carried out in order to stimulate to higher levels of public involvement in decision making in this active research area. Younger citizens is a stakeholder group that is often excluded in decision- making processes. The existence of large gaps between the involvement of older and younger stakeholders in decision making processes needs to be addressed, since such imbalances might otherwise lead to unequal opportunities between generations and limit the future consumption level of the coming generations. Another demanding task for the present generation is to assure that appropriate financial resources are injected into the Swedish Nuclear Waste Fund. It will thereby be possible for coming generations to undertake efficient measures in the decommissioning and dismantling of older nuclear facilities. To undertake such measures in line with the environmental and health codex is essential. An appropriate balance in this regard must be based on a proper understanding of the values and value functions of younger citizens. Such information must thus be an integral part of the knowledge base to be used when plans and processes are being developed for dismantling and decommissioning of nuclear power plants and other older nuclear facilities. In the present project, empirical data have been collected and compiled in a survey of the values of younger citizens with regard to decommissioning and dismantling of older nuclear facilities. The survey constitutes a stratified sample from three towns in Poland. They are Lublin, Olsztyn and Gdansk. A total of 780 students in the age group 14-19 years participated in the Survey. The results are compared to those from a similar study in the County of Kalmar in Sweden in the year 2006. The results include some major lesson learned. These may be summarised as follows: - Younger citizens tend to base their values regarding decommissioning on safety, and environmental aspects. Aspects like future economic growth and technological processes are less influential on the values. - Younger citizens tend to express a lack of information and debate as a basis of their value functions. Likewise, they tend to express interest in the topic and are open to become more included in the processes. - Younger citizens have suggestions on how more information can be made accessible to the general public. - Younger citizens need to be better included in the stakeholder process. This can be achieved by allowances from the Swedish Nuclear Waste Fund to support groups of younger citizens to follow the Swedish process of research, development and demonstration of a concept for the management of spent nuclear fuel. Less than fully accessible information campaigns about nuclear power and associated nuclear waste may result in differences in confidence levels between different groups of stakeholders. By finding out more about the values of different stakeholders it will be possible for the Swedish Radiation Safety Authority as well as for Society as a whole to enhance the possibility t o de

338

Total exploitation of an ornamental granite quarry  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper we propose a methodology to estimate the recovery percentage for each of the products which can be obtained from the exploitation of an ornamental granite quarry: block, semiblock, masonry-transverse stone, and the smaller materials that can be used to obtain construction aggregates. This methodology ensures that quarry exploitation is exhaustive, thereby minimising the production of spoils and the consequent negative impact on the environment. The analysis is based on a detailed and exhaustive compilation of discontinuity data from the research fronts, which are then interpreted statistically and projected over the three weakness planes that are a particular feature of ornamental granite deposits. Using this information, and bearing in mind the minimum commercially viable sizes for each kind of granite, the corresponding recovery rates are calculated for each material in each plane. The results are then integrated using spatial techniques, and the result is an evaluation of quarry contents with a view to total exploitation. This methodology was applied to a quarry in the opening phase in order to carry out an a priori assessment of the economic feasibility of the quarry.

En este trabajo se propone una metodología para estimar el porcentaje de recuperación de cada uno de los productos que se pueden obtener en la explotación de una cantera de granito ornamental: bloque, semibloque, manpostería y per piaños, y material restante destinado a la obtención de áridos. De esta manera se logra un aprovechamiento integral de la cantera, evitándose la generación de estériles y el subsiguiente impacto ambiental producido por éstos. La metodología de análisis se basa en la recopilación detallada y exhaustiva de datos de discontinuidades en los frentes de investigación, que se interpretan estadísticamente y se proyectan sobre los tres planos de debilidad propios del granito ornamental. Con esta información, y las dimensiones mínimas comerciales de referencia para cada tipo de material, se realiza el cálculo de las recuperaciones correspondientes de cada material en cada plano y los resultados de recuperación sobre estos tres planos se integran mediante técnicas espaciales; obteniéndose la evaluación de los recursos en la cantera para su aprovechamiento integral. La metodología ha sido aplicada a una cantera en fase de apertura para realizar una valoración inicial de su viabililidad económica.

Taboada, J.

2005-09-01

339

Glacier retreat in New Zealand during the Younger Dryas stadial.  

Science.gov (United States)

Millennial-scale cold reversals in the high latitudes of both hemispheres interrupted the last transition from full glacial to interglacial climate conditions. The presence of the Younger Dryas stadial (approximately 12.9 to approximately 11.7?kyr ago) is established throughout much of the Northern Hemisphere, but the global timing, nature and extent of the event are not well established. Evidence in mid to low latitudes of the Southern Hemisphere, in particular, has remained perplexing. The debate has in part focused on the behaviour of mountain glaciers in New Zealand, where previous research has found equivocal evidence for the precise timing of increased or reduced ice extent. The interhemispheric behaviour of the climate system during the Younger Dryas thus remains an open question, fundamentally limiting our ability to formulate realistic models of global climate dynamics for this time period. Here we show that New Zealand's glaciers retreated after approximately 13?kyr bp, at the onset of the Younger Dryas, and in general over the subsequent approximately 1.5-kyr period. Our evidence is based on detailed landform mapping, a high-precision (10)Be chronology and reconstruction of former ice extents and snow lines from well-preserved cirque moraines. Our late-glacial glacier chronology matches climatic trends in Antarctica, Southern Ocean behaviour and variations in atmospheric CO(2). The evidence points to a distinct warming of the southern mid-latitude atmosphere during the Younger Dryas and a close coupling between New Zealand's cryosphere and southern high-latitude climate. These findings support the hypothesis that extensive winter sea ice and curtailed meridional ocean overturning in the North Atlantic led to a strong interhemispheric thermal gradient during late-glacial times, in turn leading to increased upwelling and CO(2) release from the Southern Ocean, thereby triggering Southern Hemisphere warming during the northern Younger Dryas. PMID:20829791

Kaplan, Michael R; Schaefer, Joerg M; Denton, George H; Barrell, David J A; Chinn, Trevor J H; Putnam, Aaron E; Andersen, Bjørn G; Finkel, Robert C; Schwartz, Roseanne; Doughty, Alice M

2010-09-01

340

Chemistry of deep groundwaters from granitic bedrock  

International Nuclear Information System (INIS)

Water analysis data from Fjaellveden, Gideaa, Svartboberget and Kamlunge (7 different drilling holes, 26 sampling levels at vertical depths between 100 and 600 m) are discussed. Most of the waters are Na(sup)+ -Ca2(sup)+ -HCO3(sup)- -dominated with a total salt content of 200-300 mg/1 and pH of 8-9. Intrusions of Na(sup)+ -Cl(sup)- -dominated saline waters (up to 650 mg/1) are observed at great depth. The conditions are generally strongly reducing. The presence of clayish material (kaolinite, smectities) and zeolites in the fractures appears to have a large influence on the cation concentration ratios. The contents of organics, largely fulvic acids of intermediate molecular weight (180 and deuterium) indicate a non-marine origin of the water and only minor exchanges with the surroundings. The presence of tritium is evidence of intrusions of young waters in some of the samples, probably due to the disturbances during drilling and sampling. (author)

341

Sorption of actinides in granitic rock  

International Nuclear Information System (INIS)

The sorption of americium (III), neptunium(V) and plutonium on geologic media under oxic conditions has been measured by a batch technique. The aqueous phase was a synthetic groundwater or 4M NaCl solution. The solid phase was a pure mineral, representative of igneous rocks, or granite. Altogether 40 different minerals and rocks were used. The effects of pH and the ionic strength of the aqueous phase as well as of the cation exchange capacity and the surface/mass ratio of the solid sorbent are discussed. Empirical equations giving the distribution coefficient as a function of pH in the environmental pH-range 7-9 are suggested. Some observations and conclusions concerning sorption mechanisms are given. (author)

342

Expected repository environments in granite: thermal environment  

International Nuclear Information System (INIS)

This report was prepared for the Reference Repository Conditions - Interface Working Group and will be used to formulate a standardized description of repository conditions for use by the Civilian Radioactive Waste Management Program. A baseline repository in granite is defined and three waste types are considered: unreprocessed spent fuel, commercial high-level waste, and defense high-level waste. Three different scales of repository environment are described - the very-near field (near the waste canister), the near field (the room and pillar), and the far field (the entire repository and surroundings). Information was compiled from the literature and, in addition, a number of calculations were performed. The major emphasis is on describing the thermal environment although the ground-water flow and chemical and radiation environments are also described. 61 figures, 24 tables

343

Diffusion data in granite. Recommended values  

Energy Technology Data Exchange (ETDEWEB)

Diffusion data for radionuclide transport in the porous matrix of rock are proposed for Swedish rock and ground waters, for performance assessment. Suggested data are based on an experimental diffusion study, where tritiated water was used as noninteracting diffusing species in stationary diffusion experiments in Aespoe fine grained granite and diorite. These data, for tritiated water, were used as reference in our study. For other species the effective diffusivities could be predicted from knowledge of the relative behaviour of these species to that of tritiated water. The behaviour is influenced by the difference in free water diffusivity and sometimes the existence of anion exclusion of surface diffusion. Apparent diffusivities are also calculated using sorption data, in addition to the effective diffusivities. Data are proposed for high saline and low saline ground water conditions. 38 refs, 6 figs, 4 tabs.

Ohlsson, Yvonne; Neretniks, I. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Chemical Engineering and Technology

1997-10-01

344

The Granite State in Maps, 1756, 2003  

Science.gov (United States)

New Hampshire has roots in British colonial history, beginning as part of Massachusetts before it became its own state in 1788. Over the past three centuries or so, explorers and others have seen fit to map the Granite State for purposes political, cultural, and otherwise. This great digital collection from Dartmouth College brings together over 125 maps dating from the early 1770s all the way up to 2003. Visitors can search through the maps as they see fit or they can scroll through all of these cartographic gems. First-time visitors may wish to start with the remarkable 1773 map and then move on to the engaging 1860 township and rail road map of the state. It's an amazing collection and one that will delight geographers and anyone with an interest in New England history.

345

Expansion of the granitic post-orogenic magmatism in the formation of Serrinha (Northeastern Bahia, B R), Sao Francisco craton; Expansao do magmatismo granitico pos-orogenico no nucleo Serrinha (NE Bahia), craton do Sao Francisco: idade U-Pb do Macico Granitico Pedra Vermelha  

Energy Technology Data Exchange (ETDEWEB)

The Pedra Vermelha Granitic Massif, located at the North area of Serrinha Nucleus, presents a circular shape, being intrusive at the Archaean geoscience-magmatic basement rocks and the Paleoproterozoic volcano sedimentary sequences. The single zircon U-Pb dating yield a crystallization age of 2080 {+-} 8 Ma. The geological, petrographic al and litogeochemical characteristics of the studied rocks are similar to those of the Morro do Lopes granitic magmatism (2076 {+-} 6 a 2071 {+-} 6 Ma), which is located at the South area of this nucleus. These allow us to infer that those post-orogenic alkaline bodies are widespread throughout the Serrinha Nucleus and constitute its last Paleoproterozoic magmatic expression. (author)

Rios, Debora Correia; Conceicao, Herbet; Rosa, Maria de Lourdes da Silva; Marinho, Moacyr Moura [Bahia Univ., Salvador, BA (Brazil). Centro de Pesquisa em Geofisica e Geologia. Lab. de Petrologia Aplicada a Pesquisa Mineral]. E-mail: debora@cpgg.ufba.br; herbet@ufba.br; lourdes@cpgg.ufba.br; cbpmdt@cbpm.com.br; Davis, Donaldo Wayne [University of Toronto, ON (Canada). Dept. of Geology. Earth Sciences Centre]. E-mail: dond@geology.utoronto.ca

2005-09-15

346

Petrology and geochemistry of the proterozoic A-type granite of Kanigiri, Prakasam dist., Andhra Pradesh, India: implications for rare metal mineralisation  

International Nuclear Information System (INIS)

The granite pluton (6.2x2.1 km2; 995±20 Ma) at Kanigiri, Prakasam district of Andhra Pradesh constitutes the southernmost part of the Prakasam alkaline complex (PAC). PAC lies to the east of the eastern margin of the Cuddapah basin, with the Dharwar schists and gneisses to its west and the eastern ghat mobile belt to its east, and is bound by two major deep faults. It comprises silica-undersaturated nepheline syenites at Elchuru, Purimetla, and Uppalapadu, saturated syenites at Settupalli, and oversaturated granitic rocks at Kanigiri and Podili. The Kanigiri granite (KG) occurs close to a major fault represented by the NW-SE flowing Mekeru river and is intrusive into the Dharwar schists, with xenoliths of the latter in the former. Petrographically, KG is a biotite granite (s.s.) with notable content of accessory minerals like fluorite and rare metal bearing minerals viz., columbite, samarskite, fergusonite, zircon, allanite, and thorite. Geochemically, it is a low Ca, metaluminous, highly fractionated alkali granite, with enrichment of Rb, Pb, Ga, Y, Zr, U, Th, Nb, and Ta, and depletion of Ba, Sr, Ti, and P. The field, petromineralogical, and geochemical aspects indicate KG as A-type (anorogenic; within plate), with (a) affinity to abortive rift-/hot spot-related continental epirogenic uplifted granitoid (CEUG) and (b) its parental melt derived by low degree partial melting of lower crustal mafic rocks at ca. 800 degC and emplaced with a near minimum melt gC and emplaced with a near minimum melt composition at about 650 deg - 700 degC at PH2O of 5 kb (assumed). This neoproterozoic A-type CEUG is fertile for rare metals and soils derived from it are potential for polymetallic (Y, REE, Nb, and Ta) minerals. (author). 27 refs., 11 figs., 3 tabs

347

Lithium Isotopes; a Potential aid to Understanding Granite Petrogenesis  

Science.gov (United States)

Significant enrichment in 6Li occurs during the weathering of continental crustal materials to clays, contributing to depleted ?7Li in the resultant sedimentary rocks. As such Li isotopes potentially provide a unique perspective on the nature of crustal components involved granite genesis. Carboniferous-Permian granites of the New England Batholith (NEB), Australia, emplaced in a Devonian-Triassic arc setting, are subdivided into 5 major supersuites1. Bundarra and Hillgrove are both S-types, interpreted to be derived from strongly weathered arc rocks1, and immature greywackes2, respectively. Moonbi, Uralla and Clarence River represent three distinct I-type supersuites. Moonbi granites are high-K and strongly oxidised. Uralla granites are medium-high-K, and more reduced. Clarence River are low-K, isotopically primitive granites, equivalent to arc magmas. Li isotopes were evaluated using MC-ICP-MS analysis under conditions of reduced RF power. This 'cool' plasma technique yields precision equivalent to TIMS (2\\sigma SD; 0.5‰ , 680W; 0.7‰ , 800W)3. Overall variations of ~10‰ ? 7Li are observed, greater than the differences observed in arc lavas worldwide (? 7Li = ~2 to 7‰ ). Clarence River granites typically have ?7Li > 4‰ , similar to lavas from sediment poor island arcs (e.g. Izu-Bonin and Kuriles). Bundarra granites have low ?7Li, consistent with involvement of more strongly weathered source components. The higher ?7Li (isotopes provide important insights into the nature of the crustal components involved in granite magma-genesis. 1Shaw, S.E. and Flood, R.H. 1981. JGR, 86, 10530-10544. 2Landenberger, B. and Collins, W.J. 1995. In Brown, M. & Piccoli, P (eds), The origin of granites and related rocks. p86.3Bryant et al. (sub.) JAAS.

Bryant, C.; Chappell, B.; Bennett, V.

2002-12-01

348

Diffusive transport in compacted mixtures of clay and crushed granite  

International Nuclear Information System (INIS)

Diffusion coefficients are important parameters for predicting migration rates of contaminants through earthen barrier materials used in many waste containment strategies. Apparent diffusion coefficients, D, were measured for Tc and I in compacted 1:3 mixtures of Lake Agassiz clay and crushed granite. Technetium-99 and 129I are two of the most important radioisotopes present in nuclear fuel waste. Lake Agassiz clay is a glacial lake clay composed principally of smectite, illite, quartz and kaolinite. Before being mixed with clay, crushed granite was separated into the following particle size fractions: 3 and they were saturated with a Na-Ca-Cl-dominated synthetic groundwater solution having an effective ionic strength of 220 mol/m3. The mean D values (n = 4) for Tc in the mixes ranged from 20 ?m2/s when the granite particle size was 2000 to 4750 ?m to 0.19 ?m2/s when it was 2/s. The decrease in D with decreasing granite particle size is largely attributed to an increase in the extent of reduction of Tc(VII) to Tc(IV) and its subsequent sorption on Fe(III) oxyhydroxides present in granite. The reductants are probably Fe(II)-bearing minerals, such as magnetite, in granite. The finer the granite particle size, the greater the reactive surface a, the greater the reactive surface area. For I, clay controls the diffusion process and granite is essentially inert filler. The mean D values for I are about 3 ?m2/s in all cases. The results show that, depending on the environmental conditions and the nature of the diffusant, crushed granite in compacted clay-based barriers can markedly slow mass transport. (orig.)

349

A Distributed Network Intrusion Detection System with Active Surveillance Agent  

Directory of Open Access Journals (Sweden)

Full Text Available A distributed network intrusion detection system (IDS called SA-NIDS is proposed based on the network-based intrusion detection architecture. It includes three basic components, Local Intrusion Detection Monitor (LIDM, Global Intrusion Detection Controller (GIDC, and Surveillance Agent (SA. Basically, the LIDM is used to do packets capturing, packets de-multiplexing, local intrusion detection and intrusion inferring. The GIDC is installed in administration center for communicating and managing LIDMs, it can also do the intrusion detection and intrusion inferring. The SA contains several optional functions for information gathering. After an attack behavior is discovered, the SA may be used to launch some kinds of information gathering to the attacker, so that the proposed SA-NIDS has the active surveillance ability. For the intrusion inferring, the pattern matching and the statistical approach are applied in SA-NIDS. The experimental results can satisfy the needs of network information safety.    

Bin Zeng

2013-10-01

350

Vertical zonality of fractionated granite plutons reflected in zircon chemistry.  

Czech Academy of Sciences Publication Activity Database

s. l : Universidad d Salamanca ; Escuela politécnica superior de Avila ; Universidad de Granada, 2011 - (Molina, J.; Scarrow, J.; Bea, F.; Montero, P.). s. 25-25 ISBN 978-84-694-5253-0. [Hutton Symposium on Granites and Related Rocks /7./. 04.07.2011-09.07.2011, Avila] Institutional research plan: CEZ:AV0Z30130516 Keywords : zircon * granite geochemistry * granite zonality * Cínovec * Beauvoir Subject RIV: DB - Geology ; Mineralogy http://www.seventh-hutton.org/meeting/Abstracts,_posters,_Lithos_Special_Issue_files/abstracts_book_Hutton_ISBN.pdf

Breiter, Karel

351

High heat production (HHP) granites, hydrothermal circulation and ore genesis  

International Nuclear Information System (INIS)

The final paper given at the conference on high heat production granites held in St. Austell, Cornwall in September, 1985, is a commentary on the presentations and concluding discussion. Half the papers were directed to the present state of knowledge on HHP granites and mineralization. Others were concerned with the distribution of uranium and thorium in St. Austell granite and tin-tungsten mineralization. The importance of the study of the decay of radioelements in understanding the whole spectrum of geologic processes was emphasised. (UK)

352

Sorption behavior of Am(III) onto granite  

International Nuclear Information System (INIS)

Sorption behavior of Am(III) onto granite was investigated. The distribution coefficient (Kd) of Am(III) onto granite was determined in the solution pH of which was ranged from 2.9 to 11.4 and ionic strength was set at 10-2 and 10-1. The Kd values were found to increase with increasing pH and with decreasing ionic strength. The obtained data were successfully analyzed by applying an electrical double layer model. The optimum parameters of the double layer electrostatics and adsorption reactions were obtained, and the selective adsorption behavior of Am(III) onto the granite was discussed. (author)

353

2005 dossier: granite. Tome: phenomenological evolution of the geologic disposal; Dossier 2005: Granite. Tome evolution phenomenologique du stockage geologique  

Energy Technology Data Exchange (ETDEWEB)

This document makes a status of the researches carried out by the French national agency of radioactive wastes (ANDRA) about the phenomenological aspects of the geologic disposal of high-level and long-lived radioactive wastes (HLLL) in granite formations. Content: 1 - introduction: ANDRA's research program on disposal in granitic formation; 2 - the granitic environment: geologic history, French granites; 3 - HLLL wastes and disposal design concepts; 4 - identification, characterization and modeling of a granitic site: approach, geologic modeling, hydrologic and hydro-geochemical modeling, geomechanical and thermal modeling, long-term geologic evolution of a site; 5 - phenomenological evolution of a disposal: main aspects of the evolution of a repository with time, disposal infrastructures, B-type wastes disposal area, C-type wastes disposal area; spent fuels disposal area, radionuclides transfer and retention in the granitic environment; 6 - conclusions: available knowledge, methods and tools for the understanding and modeling of the phenomenological evolution of a granitic disposal site. (J.S.)

NONE

2005-07-01

354

Intrusion problematic during water supply systems’ operation  

Directory of Open Access Journals (Sweden)

Full Text Available Intrusion through leaks occurrence is a phenomenon when external fluid comes into water pipe systems. This phenomenon can cause contamination problems in drinking pipe systems. Hence, this paper focuses on the entry of external fluids across small leaks during normal operation conditions. This situation is especially important in elevated points of the pipe profile. Pressure variations can origin water volume losses and intrusion of contaminants into the drinking water pipes. This work focuses in obtaining up the physical representation on a specific case intrusion in a pipe water system. The combination of two factors is required to generate this kind of intrusion in a water supply system: on one hand the existence of at least a leak in the system; on the other hand, a pressure variation could occur during the operation of the system due to consumption variation, pump start-up or shutdown. The potential of intrusion during a dynamic or transient event is here analyzed. To obtain this objective an experimental case study of pressure transient scenario is analyzed with a small leak located nearby the transient source.

Jesus Mora-Rodriguez, P. Amparo López-Jimenez, Helena M. Ramos

2011-05-01

355

Category-Based Intrusion Detection Using PCA  

Directory of Open Access Journals (Sweden)

Full Text Available Existing Intrusion Detection Systems (IDS examine all the network features to detect intrusion or misuse patterns. In feature-based intrusion detection, some selected features may found to be redundant, useless or less important than the rest. This paper proposes a category-based selection of effective parameters for intrusion detection using Principal Components Analysis (PCA. In this paper, 32 basic features from TCP/IP header, and 116 derived features from TCP dump are selected in a network traffic dataset. Attacks are categorized in four groups, Denial of Service (DoS, Remote to User attack (R2L, Remote to User attack (U2R and Probing attack. TCP dump from DARPA 1998 dataset is used in the experiments as the selected dataset. PCA method is used to determine an optimal feature set to make the detection process faster. Experimental results show that feature reduction can improve detection rate for the category-based detection approach while maintaining the detection accuracy within an acceptable range. In this paper KNN classification method is used for the classification of the attacks. Experimental results show that feature reduction will significantly speed up the train and the testing periods for identification of the intrusion attempts.

Gholam Reza Zargar

2012-10-01

356

Stochastic Capturing Moving Intrusions by Mobile Sensors  

Science.gov (United States)

In our previous work [1], we studied Intrusion/Detection Model 1 (IDM-1), in which intrusion events occur /arrive randomly at the points of the region of interest and then fade way after a random time. In this paper, we built a stochastic model analyzing the detection quality achieved by a single sensor moving along a certain track, based on velocity and mobility pattern. We consider the modes of intrusion events defined as follows: intruders occur/arrive at random points at the edge of the field of interest, and move directly to the center of the field of interest at a constant/maximum speed. We called this model as IDM-2. In order to compare the results, two detection scenarios are studied: the robot detection scenario and the radar detection scenario. In the robot detection scenario, a robot is set to move periodically along a certain route at a constant speed. In the radar detection scenario, radar is rotated at a constant speed in a clockwise/anti-clockwise direction. An intrusion is said to be captured if it is sensed by the moving robot or radar before it arrives at the center of the field of interest. For both scenarios, we derive generalexpression for intrusion loss probability and the expected time that it takes the robot or radar to make the first capture of the intruders.

Liang, Xiannuan; Xiao, Yang

357

NETWORK INTRUSION DETECTION AND PREVENTION ATTACKS  

Directory of Open Access Journals (Sweden)

Full Text Available Intrusion detection is an important technology in business sector as well as an active area of research. It is an important tool for information security. A Network Intrusion Detection System is used to monitor networks for attacks or intrusions and report these intrusions to the administrator in order to take evasive action. Today computers are part of networked; distributed systems that may span multiple buildings sometimes located thousands of miles apart. The network of such a system is a pathway for communication between the computers in the distributed system. The network is also a pathway for intrusion. This system is designed to detect and combat some common attacks on network systems. It follows the signature based IDs methodology for ascertaining attacks. A signature based IDS will monitor packets on the network and compare them against a database of signatures or attributes from known malicious threats. In this system the attack log displays the list of attacks to the administrator for evasive action. This system works as an alert device in the event of attacks directed towards an entire network.

Harpreet kaur

2012-06-01

358

Conceptual processing of distractors by older but not younger adults.  

Science.gov (United States)

Evidence from perceptually based implicit memory tasks demonstrates greater priming from distracting information among older compared with younger adults. We examined whether older adults also show greater conceptually based implicit priming from distracting information. We measured priming using a general-knowledge test that was preceded by an incidental-encoding task (a color-naming Stroop task in one experiment and a 1-back task involving pictures with irrelevant words superimposed in a second experiment). Younger adults showed no priming from the distracting information in either experiment, whereas older adults showed reliable priming in both experiments. Thus, unlike young adults, older adults process irrelevant information conceptually and then can use that information to boost their performance on a subsequent task. PMID:25376192

Amer, Tarek; Hasher, Lynn

2014-12-01

359

Younger Dryas interval and outflow from the Laurentide ice sheet  

Science.gov (United States)

A boxmodel of the Great Lakes is used to estimate meltwater flow into the North Atlantic between 8000 and 14,000 calendar years B.P. Controls on the model include the oxygen isotopic composition of meltwaters and lake waters as measured in the shells of ostracodes. Outflow rates are highest when oxygen isotopic values of the lake waters are most negative, denoting a maximum glacial meltwater component. Flow rates reach maximum values before the onset of the Younger Dryas and after it ends. These maxima appear to be correlative with the major meltwater pulses MWP 1A and 1B. Although the resumption of North Atlantic Deep Water formation may be tied to the reduction in ice sheet melting, neither the onset nor the end of the Younger Dryas, as recorded in the Greenland Ice Sheet Project (GISP2) records, appear tied to maxima in meltwater outflow from the Laurentide ice sheet. Copyright 2000 by the American Geophysical Union.

Moore, T.C., Jr.; Walker, J.C.G.; Rea, David K.; Lewis, C.F.M.; Shane, L.C.K.; Smith, A.J.

2000-01-01

360

An independent evaluation of the Younger Dryas extraterrestrial impact hypothesis.  

Science.gov (United States)

Based on elevated concentrations of a set of "impact markers" at the onset of the Younger Dryas stadial from sedimentary contexts across North America, Firestone, Kennett, West, and others have argued that 12.9 ka the Earth experienced an impact by an extraterrestrial body, an event that had devastating ecological consequences for humans, plants, and animals in the New World [Firestone RB, et al. (2007) Proc. Natl. Acad. Sci. USA 104:16016-16021]. Herein, we report the results of an independent analysis of magnetic minerals and microspherules from seven sites of similar age, including two examined by Firestone et al. We were unable to reproduce any results of the Firestone et al. study and find no support for Younger Dryas extraterrestrial impact. PMID:19822748

Surovell, Todd A; Holliday, Vance T; Gingerich, Joseph A M; Ketron, Caroline; Haynes, C Vance; Hilman, Ilene; Wagner, Daniel P; Johnson, Eileen; Claeys, Philippe

2009-10-27

361

Personality traits and pathology in older and younger incarcerated women.  

Science.gov (United States)

Personality disorders were examined in 157 incarcerated women, using the Schedule for Nonadaptive and Adaptive Personality (SNAP; Clark, 1996) to assess 10 Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised (DSM-III-R; American Psychiatric Association, 1987) diagnostic categories and dimensions and 15 domains of trait/temperament relevant to disordered personality. Similar to both community samples and incarcerated men, older women had lower rates of personality disorders than younger women, and the difference was mostly accounted for by differences in the Cluster B disorders. In an exploratory analysis of trait and temperament scales, the older women also scored lower in Aggression, Disinhibition, Entitlement, Exhibitionism, Impulsivity, and Manipulativeness while younger women scored lower in Workaholism and Propriety. These findings suggest that remission of antisocial behavior in women may be associated with changes in lower order personality traits or temperament. PMID:11920697

Hurt, Susan; Oltmanns, Thomas F

2002-04-01

362

An overview to Software Architecture in Intrusion Detection System  

CERN Document Server

Network intrusion detection systems provide proactive defense against security threats by detecting and blocking attack-related traffic. This task can be highly complex, and therefore, software based network intrusion detection systems have difficulty in handling high speed links. This paper reviews of many type of software architecture in intrusion detection systems and describes the design and implementation of a high-performance network intrusion detection system that combines the use of software-based network intrusion detection sensors and a network processor board. The network processor acts as a customized load balancing splitter that cooperates with a set of modified content-based network intrusion detection sensors in processing network traffic.

Bahrami, Mehdi

2012-01-01

363

Acceptance of Smart Phone by Younger Consumers in Malaysia  

OpenAIRE

The sales of smart phone are rapidly increasing in Malaysia and in the global markets. Which means that, smart phone has a great opportunity in the future growth of the mobile industry. The aim of this research is to determine the acceptance of smart phone by younger consumers in Malaysia. A total of 113 useable questionnaires was collected and analyzed through SPSS. Google doc form was utilized to create the online questionnaire. The data collection method utilized in this paper was online i...

Yong Hoe Hong; Boon Heng Teh; Chin Hooi Soh

2014-01-01

364

Shock-synthesized hexagonal diamonds in Younger Dryas boundary sediments  

OpenAIRE

The long-standing controversy regarding the late Pleistocene megafaunal extinctions in North America has been invigorated by a hypothesis implicating a cosmic impact at the ?llerød-Younger Dryas boundary or YDB (?12,900 ± 100 cal BP or 10,900 ± 100 14C years). Abrupt ecosystem disruption caused by this event may have triggered the megafaunal extinctions, along with reductions in other animal populations, including humans. The hypothesis remains controversial due to absence of shocked m...

Kennett, Douglas J.; Kennett, James P.; West, Allen; West, G. James; Bunch, Ted E.; Culleton, Brendan J.; Erlandson, Jon M.; Que Hee, Shane S.; Johnson, John R.; Mercer, Chris; Shen, Feng; Sellers, Marilee; Stafford, Thomas W.; Stich, Adrienne; Weaver, James C.

2009-01-01

365

Younger Dryas deglaciation of Scotland driven by warming summers  

OpenAIRE

Resolving the full manifestation of past abrupt climate change is key to understanding the processes driving and propagating these events. As a principal component of global heat transport, the North Atlantic Ocean also is susceptible to rapid disruptions of meridional overturning circulation and thus widely invoked as a cause of abrupt climate variability in the Northern Hemisphere. We assess the impact of one such North Atlantic cold event—the Younger Dryas Stadial—on an adjacent ice ma...

Bromley, Gordon R. M.; Putnam, Aaron E.; Rademaker, Kurt M.; Lowell, Thomas V.; Schaefer, Joerg M.; Hall, Brenda; Winckler, Gisela; Birkel, Sean D.; Borns, Harold W.

2014-01-01

366

An independent evaluation of the Younger Dryas extraterrestrial impact hypothesis  

OpenAIRE

Based on elevated concentrations of a set of “impact markers” at the onset of the Younger Dryas stadial from sedimentary contexts across North America, Firestone, Kennett, West, and others have argued that 12.9 ka the Earth experienced an impact by an extraterrestrial body, an event that had devastating ecological consequences for humans, plants, and animals in the New World [Firestone RB, et al. (2007) Proc. Natl. Acad. Sci. USA 104:16016–16021]. Herein, we report the results of an ind...

Surovell, Todd A.; Holliday, Vance T.; Gingerich, Joseph A. M.; Ketron, Caroline; Haynes, C. Vance; Hilman, Ilene; Wagner, Daniel P.; Johnson, Eileen; Claeys, Philippe

2009-01-01

367

Habitual fat intake predicts memory function in younger women  

OpenAIRE

High intakes of fat have been linked to greater cognitive decline in old age, but such associations may already occur in younger adults. We tested memory and learning in 38 women (25 to 45 years old), recruited for a larger observational study in women with polycystic ovary syndrome. These women varied in health status, though not significantly between cases (n = 23) and controls (n = 15). Performance on tests sensitive to medial temporal lobe function (CANTABeclipse, Cambridge Cognition Ltd,...

Edward LeighGibson; SuzanneBarr

2013-01-01

368

Comparing asthma treatment in elderly versus younger patients.  

Science.gov (United States)

A randomised 6-month study compared two maintenance doses of budesonide/formoterol (Symbicort® Turbuhaler® (h) maintenance and reliever therapy (Symbicort SMART®), 160/4.5 ?g 1 × 2 and 2 × 2, in 8053 asthmatics with symptoms despite treatment with inhaled corticosteroids ± inhaled long-acting ?2-agonists. This analysis compared response to the two treatments in elderly patients, ? 65 years, with that in younger patients. Elderly patients with early- or late-onset asthma were also compared. Elderly patients had lower post-bronchodilator FEV1 percentage predicted normal at baseline than younger patients (85.6% vs. 91.0%, respectively). The elderly had more exacerbations and risk of first severe exacerbation was increased by 55.3% (hazard ratio 1.553; 95% confidence interval: 1.249-1.931, p budesonide/formoterol maintenance and reliever therapy treatment in the elderly. Five-item Asthma Control Questionnaire (ACQ-5) scores improved equally in the two age groups. Changes in mean ACQ-5 scores between 1 × 2 and 2 × 2 were significant in both age groups but not clinically relevant (? 65 years, 0.12; p = 0.018; Budesonide/formoterol maintenance and reliever therapy (1 × 2 or 2 × 2) is an effective, well-tolerated and practical treatment concept in elderly and younger asthmatic patients. PMID:21435854

Haughney, J; Aubier, M; Jørgensen, L; Ostinelli, J; Selroos, O; van Schayck, C P; Buhl, R

2011-06-01

369

The intrusive complexof the Island of Giglio: geomagnetic characteristics of plutonic facies with low susceptibility contrast  

Directory of Open Access Journals (Sweden)

Full Text Available Two main plutonic facies characterize the intrusive complex of the Island of Giglio, and the trend of their contact at depth has been modelled using a 2D½ analysis based on a detailed geomagnetic survey in order to verify the geological hypothesis of the subsurface geometry of this contact. The magnetic anomaly connected with the discontinuity is quite low, due to the small difference between the magnetic susceptibilities of the two granitic facies. Development of this model of inversion of the magnetic field, which is in good agreement with the geological interpretation, was made possible by: 1 accurate control of the geomagnetic time variations and consequent temporal reduction, 2 a very low level of the artificial magnetic noise, 3 high density of the magnetic survey, 4 detailed knowledge of the mapped geologic contact between facies and of their petrologic characteristics, and 5 direct local measurements of the magnetic susceptibilities of the key lithologies. The model shows the trends of the geological contact, as projected in three E-W sections, that dips eastward in the range between 210 and 540, supporting the geologic hypothesis that the Pietrabona facies represents an external shell of the shallowly emplaced Giglio monzogranite intrusion.

R. Cavallini

1998-06-01

370

Cambro-Ordovician Granites in the Araçuaí Belt, in Brazil: snapshots from a late orogenic collapse  

Science.gov (United States)

Along the Brazilian Coast, surrounding the São Francisco Craton and adjacent mobile belts, deep segments of a Neoproterozoic orogen (Araçuaí-West Congo) generated over 120 Ma of successive magmatic episodes of granitic magmatism. The c.630-585 Ma calc-alkaline magmatic arc consists of metatonalite to metagranodiorite, with metadioritic to noritic facies and enclaves. During the syn-collisional and crustal thickening stage (c. 585 to 560 Ma) S-type metagranites have been built by dehydration melting of a diverse package of sediments. Around 545-525 Ma late orogenic crustal remelting formed mostly non-foliated garnet-cordierite leucogranites. In the post-orogenic stage (c. 510-480 Ma) inversely zoned calc-alkaline to alkaline plutons intruded previous units. This work will focus on the youngest post-orogenic magmatism. It will present the state of the art by reviewing structural measurements, detailed mapping of flow patterns and additional geochemical and isotopic data. The architecture of around 10 plutons, ranging from c. 20 to 200 km2 in surface area, unravels deep mushroom- to funnel-like magma chambers and/or conduits. Available data point towards different compositional domains, which are interfingered in complex concentric layers, so that, each pluton depicts a unique internal flow pattern. In the silica-richer structures concentric fragmented or folded layers of granite, in a hybrid K-gabbroic/dioritic matrix, contrast with predominantly homogeneous K-basaltic to gabbroic regions. These may be separated by magmatic shear zones where mixing is enhanced, also resulting in hybrid compositions. Sharp and pillow-like contacts between granitic and K-basaltic rocks locally depict a frozen-in situation of different intrusive episodes. In the silica-poorer plutonic bodies gradational contacts are more frequent and may be the result of convection enhanced diffusion. For all plutons, however, mostly sub-vertical internal contacts between most- and least-differentiated rocks, suggest generation from predominat large magma bodies of variable composition, which crystallized while crossing the middle to lower crust (magmas with the production of hybrid rock compositions. They provide, therefore, outstanding evidence for a major process of mixing between contrasting magmas, which have been generated from different sources and depths. These are considered to have originated from the orogenic collapse with coeval crustal and mantelic contributions changing in space and time.

De Campos, Cristina P.; Mendes, Júlio Cesar; de Medeiros, Silvia Regina; Ludka, Isabel P.

2014-05-01

371

Isotopic evidence for the provenance of some Caledonian granites  

International Nuclear Information System (INIS)

A combined Nd- and Sr-isotope study of Caledonian granites in Scotland and northern England demonstrates the importance of continental crust in their petrogenesis and places limits on the involvement of contemporary mantle-derived material. (author)

372

Mechanical properties of granitic rocks from Gideaa, Sweden  

International Nuclear Information System (INIS)

The elastic and mechanical properties were determined for two rock types from the Gideaa study area. Gideaa is located approximately 30 km north-east of Oernskoeldsvik, Northern Sweden. The rock types that were tested were migmatitic gneiss and migmatitic granite. The following tests were conducted: - sound velocity measurements; - uniaxial compression tests with acoustic emission recording; - brazilian disc tests; - triaxial tests; - three point bending tests. All together, 12 rock samples were tested with each test method. Six samples of these were migmatic gneiss and six samples were migmatitic granite. The result shows that the migmatitic gneiss has varying strength properties with low compressive strength in comparison with its high tensile strength. The migmatitic granite, on the other hand, is found to have parameter values similar to other granitic rocks. With 15 refs. (Author)

373

Selective adsorption behavior of cesium ions onto granite  

International Nuclear Information System (INIS)

The adsorption behavior of Cs+ onto granite was investigated. The distribution coefficient (Kd) of Cs+ onto granite was determined in the solution of which pH was ranged from 2.3 to 10.9 and ionic strength was set at 10-2 and 10-1. It is found that the Kd values for granite were larger than those for quartz, and the Kd values were found to increase with increasing pH and with decreasing ionic strength. The obtained data were successfully analyzed by an electrical double layer model and the optimum parameter values of the double layer electrostatics and adsorption reactions were obtained. The selective adsorption behavior of Cs+ onto the mineral components was discussed, and Cs+ were considered to be mainly adsorbed onto feldspars in the granite. (author)

374

Temperature dependence of uniaxial compressive strength of Hnilec granite  

OpenAIRE

Paper presents the results of the temperature dependence of uniaxial compressive strength of Hnilec Granite. The measurements of the uniaxial compressive strength were carried out at five different temperatures.

Laba? Milan

1997-01-01

375

Surface weathering of rapakivi granite outcrops – implications for natural stone exploration and quality evaluation  

OpenAIRE

Implications of surface weathering of rapakivi granite outcrops for natural stone evaluation were studied in the Wiborg rapakivi granite batholith in southeastern Finland. The study was performed as field mapping, comprising the whole batholith and as detailed investigations on selected outcrops. The Wiborg batholith is composed of wiborgite, pyterlite, even-grained rapakivi granite, porphyritic rapakivi granite, porphyry aplite, and gabbro-anorthosite. Wiborgite is the main rapakivi granite ...

Ha?rma?, Paavo; Selonen, Olavi

2008-01-01

376

Advances in Intrusion Detection System for WLAN  

Directory of Open Access Journals (Sweden)

Full Text Available A wireless network is not as secure as compare the wired network because the data is transferred on air so any intruder can use hacking techniques to access that data. Indeed it is difficult to protect the data and provide the user a secure information system for lifetime. An intrusions detection system aim to detect the different attacks against network and system. An intrusion detection system should be capable for detecting the misuse of the network whether it will be by the authenticated user or by an attacker. Cross layer based technique help to make decision based on two layer physical layer where we compute RSS value and on MAC layer where one compute RTS-CTS time taken. This will reduce the positive false rate.They detect attempts and active misuse either by legitimate users of the information systems or by external. The paper has higlighted the advances in intrusion detection in wireless local area network.

Ravneet Kaur

2011-10-01

377

Detecting intrusions through attack signature analysis  

Energy Technology Data Exchange (ETDEWEB)

Intrusion detection has generally been based on defining normal user behavior through profiles and rule-based systems and on identifying significant deviations from such behavior as anomalous. An alternative, or a supplementary, strategy for detecting intrusions is based on attack signature analysis, whose objective is to define and recognize events or sequences of events as attack-type behavior. Such event sequences, which may constitute part of a larger attack, may be employed to exploit certain system flaws or known vulnerabilities. This paper concentrates on attack signature analysis in general, and on a preliminary version of the signature analysis module of the distributed intrusion detection system (DIDS) in particular. A signature representation is developed, a number of attack scenarios and their corresponding signatures are outlined, and mechanisms to detect the signatures are discussed.

Snapp, S.R. [Haystack Labs., Inc., Austin, TX (United States); Mukherjee, B.; Levitt, K.N. [Lawrence Livermore National Lab., CA (United States)

1991-10-11

378

Trusted Computing Based Collaborative Intrusion Detection System  

Directory of Open Access Journals (Sweden)

Full Text Available Collaboration and information sharing has obliged participating parties to look for improved detection accuracy and reaction speed in Distributed Intrusion Detection Systems (DIDS solutions. This is mainly due to the increasing number of attacks as well as increasingly sophisticated intrusions and more alarmingly various critical components of a system can be targeted. This is further exasperated by the fact that most DIDS models do not consider the attacks targeting the collaborative network itself. We specifically find this issue to be very critical and hence in this paper we propose a trust aware DIDS simulation model that is capable of categorizing each participating IDS expertise (i.e. speciality and competence, therefore helps collaborating organizations to consult our simulation model for choosing the right candidate for any type of intrusion. We call our Model as Consultative Trusted Computing-based Collaborative IDS (CTC IDS. We utilize the Trusted Platform Module (TPM for integrity evaluation and fine-tuning peer evaluation.

Jamalul-Lail Ab Manan

2012-01-01

379

Applying Fast String Matching to Intrusion Detection  

Energy Technology Data Exchange (ETDEWEB)

The performance of signature-based network intrusion detection tools is dominated by the string matching of packets against many signatures. In this paper we study how the popular intrusion detecton system Snort can be best optimized to utilize different string matching algorithms. We analyze the performance of Snort's current string matching algorithm, Boyer-Moore, and several alternate algorithms. We show that no single algorithm is fastest in the context of a real Snort rule set. Instead, we develop a hybrid system that utilizes three different search algorithms, including one new algorithm presented in this paper. The result is a system that matches many common packets 5 times faster with an average speedup of 50%. While the context of our analysis is intrusion detection, other problem domains such as virus scanning, firewalls, and layer seven switches benefit from our work.

Fisk, M. E. (Mike E. ); Varghese G. (George)

2001-01-01

380

Developing Mobile Agent for Intrusion Detection  

Directory of Open Access Journals (Sweden)

Full Text Available Mobile agent is a certain agent actively able to move from one computer to another or even travel acrossnetwork to perform the task assigned. This research aimed to develop mobile agent model to detectdistributed intrusion (Distributed Intrusion Detection System.It was expected that the produced model was able to perform its task in nearly real time manner, to beimmune against attack, and also fairly small overhead at the host, either in memory consumption or CPUusage. In this research, the Aglets concept was also developed to aid intrusion detection. This approachwas also maintained to solve certain issues such as scalability, reliability, and configurability. Hence, theadvantages and limitations of agent-based approaches will be when it is applied in real world.

Bambang Sugiantoro

2013-05-01

381

An Architecture of Hybrid Intrusion Detection System  

Directory of Open Access Journals (Sweden)

Full Text Available Intrusion Detection System (IDS is renowned and widely-deployed security tool to detect attacks and malicious activities in information system. It is an essential element of any contemporary information system. There are mainly two techniques for intrusion detection: i signature-based (misuse detection and ii anomaly-based detection technique. Both the techniques have their advantages and disadvantages. This paper presents research from an ongoing study on the use of features of both the intrusion detection techniques to design a novel and efficient hybrid IDS. An architecture and implementation details of our hybrid IDS are presented. Furthermore, unique characteristics of our hybrid IDS are described. This paper concludes with future research directions and challenges in IDS.

Kanubhai K Patel

2012-12-01

382

Earth's youngest exposed granite and its tectonic implications: the 10–0.8 Ma Kurobegawa Granite  

OpenAIRE

Although the quest for Earth's oldest rock is of great importance, identifying the youngest exposed pluton on Earth is also of interest. A pluton is a body of intrusive igneous rock that crystallized from slowly cooling magma at depths of several kilometers beneath the surface of the Earth. Therefore, the youngest exposed pluton represents the most recent tectonic uplift and highest exhumation. The youngest exposed pluton reported to date is the Takidani Granodiorite (~ 1.4 Ma) in the Hida Mo...

Hisatoshi Ito; Ryuji Yamada; Akihiro Tamura; Shoji Arai; Kenji Horie; Tomokazu Hokada