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Sample records for basalts ivisaartoq greenstone

  1. Field and geochemical characterisitics of the Mesoarchean (~3075 ma) Ivisaartoq greenstone belt, southern West Greenland: Evidence for seafloor hydrothermal alteration in a supra-subduction oceanic crust

    DEFF Research Database (Denmark)

    Polat, A.; Appel, P.W.U.; Frei, Robert;

    2006-01-01

    The Mesoarchean (ca. 3075 Ma) Ivisaartoq greenstone belt in southern West Greenland includes variably deformed and metamorphosed pillow basalts, ultramafic flows (picrites), serpentinized ultramafic rocks, gabbros, sulphide-rich siliceous layers, and minor siliciclastic sedimentary rocks. Primary......-enriched, near-flat HREE, and HFSE (especially Nb)-depleted trace element patterns, indicating a subduction zone geochemical signature. Ultramafic pillows and cumulates display large positive initial eNd values of + 1.3 to + 5.0, consistent with a strongly depleted mantle source. Given the geological...

  2. An overview of the lithological and geochemical characteristics of the Mesoarchean (ca. 3075) Ivisaartoq greenstone belt, southern West Greenland

    DEFF Research Database (Denmark)

    Polat, A.; Frei, Robert; Appel, P.W.U.;

    2008-01-01

    Ca-plagioclase and are interpreted as anorthositic cumulates of the lower oceanic crust brought to the surface by upwelling gabbroic magmas. Alternatively, the inclusions may represent the xenoliths from older (>3075 Ma) anorthositic crust onto which the Ivisaartoq magmas were emplaced as an...

  3. Petrology and geochemistry of metamorphosed komatiites and basalts from the Sula Mountains greenstone belt, Sierra Leone

    Science.gov (United States)

    Rollinson, Hugh

    The Sula Mountains greenstone belt is the largest of the late-Archaean greenstone belts in the West African Craton. It comprises a thick (5km) lower volcanic formation and a thinner (2km) upper metasedimentary formation. Komatiites and basalts dominate the volcanic formation and komatiites form almost half of the succession. All the volcanic rocks are metamorphosed to amphibolite grade and have been significantly chemically altered. Two stages of alteration are recognised and are tentatively ascribed to hydrothermal alteration and later regional amphibolite facies metamorphism. Ratios of immobile trace elements and REE patterns preserve, for the most part, original igneous signatures and these are used to identify five magma types. These are: low-Ti komatiites - depleted in light REE; low-Ti komatiites - with flat REE patterns; high-Ti komatiitic basalts - with flat REE; low-Ti basalts - depleted in light REE; high-Ti basalts - with flat REE patterns. Much of the variation between the magma types can be explained in terms of different melt fractions of the mantle source, although there were two separate mantle sources one light REE depleted, the other not. The interleaving of the basalts and komatiites produced by this melting indicates that the two mantle sources were melted simultaneously. The simplest model with which to explain these complex melting processes is during melting within a rising mantle plume in which there were two different mantle compositions. The very high proportion of komatiites in the Sula Mountains relative to other greenstone belts suggests either extensive deep melting and/or the absence of a thick pre-existing crust which would have acted as a ``filter'' to komatiite eruption.

  4. A great thermal divergence in the mantle beginning 2.5 Ga : geochemical constraints from greenstone basalts and komatiites.

    OpenAIRE

    Condie, K.C.; Aster, R.C.; J. van Hunen

    2016-01-01

    Greenstone basalts and komatiites provide a means to track both mantle composition and magma generation temperature with time. Four types of mantle are characterized from incompatible element distributions in basalts and komatiites: depleted, hydrated, enriched and mantle from which komatiites are derived. Our most important observation is the recognition for the first time of what we refer to as a Great Thermal Divergence within the mantle beginning near the end of the Archean, which we ascr...

  5. Magmatic origin of low-T mafic blueschist and greenstone blocks from the Franciscan mélange, San Simeon, California

    Science.gov (United States)

    Ukar, Estibalitz; Cloos, Mark

    2015-08-01

    The Franciscan mélange exposure near San Simeon contains abundant greenstone and minor blueschist blocks that were tectonically boudinaged while encased in the shale-matrix. Tectonic deformation of the blueschists is evident from variable amounts of cataclastic flow along their margins and in pinched tails. Major, trace, and rare earth elemental analyses indicate that blueschist and greenstone blocks in this area of the mélange were derived from sources with MORB-like composition along with some having trace element and REE patterns similar to OIB compositions. Most blocks are low LREE basalts that probably formed in an open ocean ridge setting, but some blocks have high LREE contents similar to off-axis seamounts. Linear trends of incompatible elements for both blueschist and greenstone blocks indicate that both lithologies were probably derived from a similar, variably fractionated, tholeiitic magma. Blueschist blocks with sodic amphibole + lawsonite ± epidote were pervasively recrystallized at 300-350 °C and foliated during ductile deformation that included folding. Their protolith can only be identified as mafic. A few blocks contain very small amounts of metasedimentary materials indicating some were probably seafloor basalts, but some may have been diabase or even gabbro. Where interlayered sediment was present, the mafic protolith was enriched in K, Rb, and Na. Greenstones, on the other hand, contain abundant pseudomorphic evidence of magmatic textures. Alteration to albite, chlorite and pumpellyite at temperatures of 100-200 °C is intense, especially in cataclastic margins and pinched tails. Some of the basaltic greenstones have attached radiolarian chert, and a few have relict diabasic textures. The mafic blueschists and greenstones in the mélange near San Simeon are probably fragments from the uppermost part of the Farallon plate. The blueschists may be mostly mafic slabs uprooted from the subducting crust, underplated to the base of the North

  6. Geochemistry of the Neoarchaean Volcanic Rocks of the Kilimafedha Greenstone Belt, Northeastern Tanzania

    Directory of Open Access Journals (Sweden)

    Charles W. Messo

    2012-01-01

    Full Text Available The Neoarchaean volcanic rocks of the Kilimafedha greenstone belt consist of three petrological types that are closely associated in space and time: the predominant intermediate volcanic rocks with intermediate calc-alkaline to tholeiitic affinities, the volumetrically minor tholeiitic basalts, and rhyolites. The tholeiitic basalts are characterized by slightly depleted LREE to nearly flat REE patterns with no Eu anomalies but have negative anomalies of Nb. The intermediate volcanic rocks exhibit very coherent, fractionated REE patterns, slightly negative to absent Eu anomalies, depletion in Nb, Ta, and Ti in multielement spidergrams, and enrichment of HFSE relative to MORB. Compared to the other two suites, the rhyolites are characterized by low concentrations of TiO2 and overall low abundances of total REE, as well as large negative Ti, Sr, and Eu anomalies. The three suites have a εNd (2.7 Ga values in the range of −0.51 to +5.17. The geochemical features of the tholeiitic basalts are interpreted in terms of derivation from higher degrees of partial melting of a peridotite mantle wedge that has been variably metasomatized by aqueous fluids derived from dehydration of the subducting slab. The rocks showing intermediate affinities are interpreted to have been formed as differentiates of a primary magma formed later by lower degrees of partial melting of a garnet free mantle wedge that was strongly metasomatized by both fluid and melt derived from the subducting oceanic slab. The rhyolites are best interpreted as having been formed by shallow level fractional crystallization of the intermediate volcanic rocks involving plagioclase and Ti-rich phases like ilmenite and magnetite as well as REE-rich phases like apatite, zircon, monazite, and allanite. The close spatial association of the three petrological types in the Kilimafedha greenstone belt is interpreted as reflecting their formation in an evolving late Archaean island arc.

  7. The auriferous placer at Mount Robert, Pietersburg Greenstone belt

    International Nuclear Information System (INIS)

    The Mount Robert gold placer near Potgietersrus occurs in coarse, matrix-supported conglomerates of the Uitkyk Formation within the Pietersburg greenstone belt. Sedimentological and mineralogical investigations indicate that the conglomerates and the ore minerals were derived from a greenstone provenance, and that they were deposited in a braided river environment within a rapidly subsiding trough. Lack of sedimentological concentration of the heavy minerals is considered to be the main reason for the low and erratic gold grades encountered (usually below 1 g/t) and, thus, the failure of all past mining ventures. The mineralogical composition of the Mount Robert ore closely resembles that of the Witwatersrand deposits. However, uraninite is absent, probably as a result of its complete removal by weathering processes. Remaining small uranium concentrations can still be detected within the conglomerates where they occur associated with grains of carbonaceous matter, leucoxene aggregates, and secondary iron-hydroxides. U3O8 values found in the conglomerates are given

  8. Archaean greenstone belts and associated granitic rocks - A review

    Science.gov (United States)

    Anhaeusser, Carl R.

    2014-12-01

    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

  9. Basaltic Magmatism: The Dominant Factor in the Petrologic and Tectonic Evolution of the Earth

    Science.gov (United States)

    Lowman, Paul D., Jr.

    2003-01-01

    Silicate bodies such as the Moon, Mars, probably Mercury, and possibly Venus, appear to have evolved in three main stages: a first (felsic) differentiation, a late heavy bombardment, and a second (basaltic) differentiation. It has been proposed that the Earth underwent a similar sequence. This paper argues that the second differentiation, basaltic magmatism, has dominated the petrologic and tectonic evolution of the Earth for four billion years. A global andesitic crust, formed during and after accretion of the planet, was disrupted by major impacts that triggered mantle upwelling and sea-floor spreading about 4 billion years ago. The oceanic crust collectively has since been formed by basaltic volcanism, from spreading centers and mantle plumes. However, the continental crust has also been greatly affected. Basaltic underplating has promoted anatexis and diapiric intrusion of granitoids in granite-greenstone terrains, as well as providing heat for regional metamorphism. Basaltic intrusions, such as the Nipissing diabase of the Sudbury area, have added to the thickness of continental crust. Satellite magnetic surveys suggest that there are more such basaltic intrusions than previously realized; examples include the Bangui anomaly of central Africa and the Kentucky anomaly. Basaltic overplating from mafic dike swarms has repeatedly flooded continents; had it not been for erosion, they would be covered with basalt as Venus is today. The tectonic effects of basaltic volcanism on continents have only recently been realized. The World Stress Map project has discovered that continents are under horizontal compressive stress, caused by push from mid-ocean ridges, i.e., by basaltic volcanism. The stress fields are generally uniform over large intraplate areas, and could contribute to intraplate tectonism. Seafloor spreading has demonstrably been effective for at least 200 million years, and ridge push thus a contributor to tectonic activity for that long. Collectively, the

  10. Archaean greenstone belt tectonism and basin development: some insights from the Barberton and Pietersburg greenstone belts, Kaapvaal Craton, South Africa

    Science.gov (United States)

    de Wit, Maarten J.

    The sediments in two of South Africa's major Archaean greenstone belts, the Barberton and Pietersburg greenstone belts, span an age range of some 800 million years. Both greenstone belts represent remnants of extensive fold and thrust belts with complex, but different polyphase tectonic histories. The oldest sediments were deposited between circa 3470 and 3490 M.a. on oceanic like crust preserved in the Barberton belt, possibly at the same time as sedimentation on similar oceanic crust preserved in the Pietersburg belt. Thereafter, the geologic evolution of these two belts diverged considerably. In the Barberton belt, there is clear evidence that the oceanic crust and sediments were obducted onto an intra-arc basin environment within 50 million years of its formation. The sequence was later further imbricated by northwest directed thrust stacking between 3300-3200 M.a. Basin development during both periods of thrusting took place in close proximity to active "calc-alkaline" arc systems. Deformation of the sediments within these basins took place while the same sediments were being deposited. Sedimentation took place predominantly in subaqueous environments, ranging from submarine mid-fans below the photic zone to tidal flats and deltaic plains. The sediments represent a polyhistory successor-type basin: early basins developed along a complex subduction related plate boundary; these basins later evolved into foreland depositories along and within collisional environments of an accretionary orogen. Late in the history of the Barberton greenstone belt (circa 3100 M.a.), the rocks were in places thermally reactivated and probably subjected to extensional processes; these processes overlapped in time with the main episodes of economic gold mineralization, and are of "early Witwatersrand-basin" age. The oceanic-like crust (including associated sediments) preserved in the Pietersburg belt was not significantly deformed until at least 500 million years after its formation

  11. Petrogenesis of basalts from the Archean Matachewan Dike Swarm Superior Province of Canada

    Science.gov (United States)

    Nelson, Dennis O.

    1987-01-01

    The Matachewan Dike swarm of eastern Ontario comprises Archean age basalts that were emplaced in the greenstone, granite-greenstone, and metasedimentary terrains of the Superior Province of Canada. The basalts are Fe-rich tholeiites, characterized by the near ubiquitos presence of large, compositionally uniform, calcic plagioclase. Major and trace element whole-rock compositions, along with microprobe analyses of constituent phases, from a group of dikes from the eastern portion of the province, were evaluated to constrain petrological processes that operated during the formation and evolution of the magmas. Three compositional groupings, were identified within the dikes. One group has compositional characteristics similar to modern abyssal tholeiites and is termed morb-type. A second group, enriched in incompatible elements and light-REE enriched, is referred to as the enriched group. The third more populated group has intermediate characteristics and is termed the main group. The observation of both morb-type and enriched compositions within a single dike strongly argues for the contemporaneous existence of magmas derived through different processes. Mixing calculations suggest that two possibilities exist. The least evolved basalts lie on a mixing line between the morb-type and enriched group, suggesting mixing of magmas derived from heterogeneous mantle. Mixing of magmas derived from a depleted mantle with heterogeneous Archean crust can duplicate certain aspects of the Matachewan dike composition array.

  12. Re-appraisal of the Santa Rita Greenstone Belt stratigraphy, central Brazil, based on new U-Pb SHRIMP age and Sm-Nd data of felsic metavolcanic rocks

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    Pimentel, Marcio Martins; Jost, Hardy; Fuck, Reinhardt Adolfo; Junges, Sergio Luiz [Brasilia Univ., DF (Brazil). Inst. de Geociencias]. E-mail: marcio@unb.br; Armstrong, Richard [Australian National Univ., Canberra, ACT (Australia). Research School of Earth Sciences; Resende, Marcelo Goncalves [Universidade Catolica de Brasilia, DF (Brazil). Curso de Graduacao em Engenharia Ambiental

    2000-03-01

    The Santa Rita greenstone belt represents one of the supracrustal belts of the Archaen terranes of Goias, central Brazil. The stratigraphic sequence of this greenstone belt comprises a lower of komatities and basalts and an upper metasedimentary unit made of carbonaceous schits, chert, iron formation and marble, unconformably overlain by clastic metasedimentary rocks. Felsic metavolcanics occur at the interface between the metabasalts and the upper metasedimentary pile. U-Pb SHRIMP age for zircons from the felsic metavolcanics reveal that it is not part of the Archaean sequence, but represents the product of mesoproterozoic (1580 {+-} 12 Ma) magmatic event. Sm-Nd isotopic data (initial e{sub CHUR} values between -10.5 and -14.9) and T{sub DM} values of 3.0 and 3.2 Ga, within the range of the surrounding TTG terranes, indicate that the original felsic magmas were produced by re-melting of Archaen crust. The data demonstrate that the Goias greenstone belt contains infolded and imbricated proterozoic rocks, as previously suggested by Sm-Nd isotopic analyses of some of the upper detrital metasedimentary rocks. (author)

  13. Re-appraisal of the Santa Rita Greenstone Belt stratigraphy, central Brazil, based on new U-Pb SHRIMP age and Sm-Nd data of felsic metavolcanic rocks

    International Nuclear Information System (INIS)

    The Santa Rita greenstone belt represents one of the supracrustal belts of the Archaen terranes of Goias, central Brazil. The stratigraphic sequence of this greenstone belt comprises a lower of komatities and basalts and an upper metasedimentary unit made of carbonaceous schits, chert, iron formation and marble, unconformably overlain by clastic metasedimentary rocks. Felsic metavolcanics occur at the interface between the metabasalts and the upper metasedimentary pile. U-Pb SHRIMP age for zircons from the felsic metavolcanics reveal that it is not part of the Archaean sequence, but represents the product of mesoproterozoic (1580 ± 12 Ma) magmatic event. Sm-Nd isotopic data (initial eCHUR values between -10.5 and -14.9) and TDM values of 3.0 and 3.2 Ga, within the range of the surrounding TTG terranes, indicate that the original felsic magmas were produced by re-melting of Archaen crust. The data demonstrate that the Goias greenstone belt contains infolded and imbricated proterozoic rocks, as previously suggested by Sm-Nd isotopic analyses of some of the upper detrital metasedimentary rocks. (author)

  14. Geochemical evolution of magmatism in Archean granite-greenstone terrains

    Science.gov (United States)

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

    2006-05-01

    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

  15. Polyphase thrust tectonic in the Barberton greenstone belt

    Science.gov (United States)

    Paris, I. A.

    1986-01-01

    In the circa 3.5 by-old Barberton greenstone belt, the supracrustal rocks form a thick and strongly deformed thrust complex. Structural studies in the southern part of the belt have shown that 2 separate phases of over-thrusting (D sub 1 and D sub 2) successively dismembered the original stratigraphy. Thrust nappes were subsequently refolded during later deformations (D sub 3 and D sub 4). This report deals with the second thrusting event which, in the study region appears to be dominant, and (unlike the earlier thrusting), affects the entire supracrustal pile. The supracrustal rocks form a predominantly NE/SW oriented, SE dipping tectonic fan (the D sub 2 fan) in which tectonic slices of ophiolitic-like rocks are interleaved with younger sedimentary sequences of the Diepgezet and malalotcha groups. Structural and sedimentological data indicate that the D sub 2 tectonic fan was formed during a prolonged, multi-stage regional horizontal shortening event during which several types of internal deformation mechanisms were successively and/or simultaneously active. Movement appears to have been predominantly to the NW and to the N. During D sub 2, periods of quiescence and sedimentation followed periods of thrust propagation. Although the exact kinematics which led to the formation of this fan is not yet known, paleoenvironmental interpretations together with structural data suggest that D sub 2 was probably related to (an) Archean collision(s).

  16. Rb–Sr and Sm–Nd isotope systematics and geochemical studies on metavolcanic rocks from Peddavura greenstone belt: Evidence for presence of Mesoarchean continental crust in easternmost part of Dharwar Craton, India

    Indian Academy of Sciences (India)

    M Rajamanickam; S Balakrishnan; R Bhutani

    2014-07-01

    Linear, north–south trending Peddavura greenstone belt occurs in easternmost part of the Dharwar Craton. It consists of pillowed basalts, basaltic andesites, andesites (BBA) and rhyolites interlayered with ferruginous chert that were formed under submarine condition. Rhyolites were divided into type-I and II based on their REE abundances and HREE fractionation. Rb–Sr and Sm–Nd isotope studies were carried out on the rock types to understand the evolution of the Dharwar Craton. Due to source heterogeneity Sm–Nd isotope system has not yielded any precise age. Rb–Sr whole-rock isochron age of 2551 ± 19 (MSWD = 1.16) Ma for BBA group could represent time of seafloor metamorphism after the formation of basaltic rocks. Magmas representing BBA group of samples do not show evidence for crustal contamination while magmas representing type-II rhyolites had undergone variable extents of assimilation of Mesoarchean continental crust (< 3.3 Ga) as evident from their initial Nd isotope values. Trace element and Nd isotope characteristics of type I rhyolites are consistent with model of generation of their magmas by partial melting of mixed sources consisting of basalt and oceanic sediments with continental crustal components. Thus this study shows evidence for presence of Mesoarchean continental crust in Peddavura area in eastern part of Dharwar Craton.

  17. Zircon Lu-Hf systematics: Evidence for the episodic development of Archaean greenstone belts

    Science.gov (United States)

    Smith, P. E.; Tatsumoto, M.; Farquhar, R. M.

    1986-01-01

    A combined U-Th-Pb and Lu-Hf isotopic study of zircons was undertaken in order to determine the provenance and age of an Archean granite-greenstone terrain and to test the detailed application of the Lu-Hf system in various Archean zircons. The eastern Wawa subprovince of the Superior province consists of the low grade Michipicoten and Gamitagama greenstone belts and the granitic terrain. The Hf isotopic data indicate that the typical lithological features of a greenstone belt cycle could be accommodated in a crustal growth model that involved decreasing depth of melting in three isotopically distinct reservoirs: mantle, lower crust and upper crust. The model age of the sources given by the intersection of the lower crustal curve with the bulk earth evolution curve is about 2900 My, in good agreement with the zircon U-Pb basement age. This linear array also has a similar intersection age to that of Proterozoic carbonatite complexes. The general convergence of the other reservoir vectors around this age suggests that mantle depletion, crustal extraction and intracrustal differentiation were all part of the same episodic event. It is also apparent that recycling of older basement was important in the formation of many of the later greenstone belt rocks.

  18. Diamonds in an Archean greenstone belt: Diamond suites in unconventional rocks of Wawa, Northern Ontario (Canada)

    Science.gov (United States)

    Kopylova, Maya; Bruce, Loryn; Ryder, John

    2010-05-01

    Diamonds typically are found on Archean cratons entrained by younger Phanerozoic kimberlites. In contrast, Wawa diamonds are hosted in "unconventional", non-kimberlitic rocks that formed contemporaneously with the mafic and sedimentary rocks of the Archean Michipicoten Greenstone Belt (MGB). We studied two diamond suites that occur within the 2.9-2.7 Ga greenschist facies rocks of MGB located in the southwest portion of the Superior Craton (E. Canada). The first diamond suite henceforth referred to as the Wawa breccia diamonds (384 stones), are hosted in the 2618-2744 Ma calc-alkaline lamprophyres and volcaniclastic breccias, contemporaneous with pillow basalts and felsic volcanics of MGB. The second suite, the Wawa conglomerate diamonds (80 crystals), are hosted in the 2697-2700 Ma poorly sorted sedimentary polymictic conglomerate which is interpreted as a proximal alluvial fan debris flow in a fan-delta environment. The majority of the diamonds was found within the matrix of the conglomerate. The diamondiferous breccia occurs 20 km north of the town of Wawa, whereas the conglomerate is found 12 km northeast of Wawa. Diamonds from the 2 occurrences were characterized and described for provenance studies. Both the breccia and conglomerate diamonds show similar crystal habits, with the predominance of octahedral single crystals and ~ 10% of cubes. The conglomerate diamonds are significantly less resorbed (no resorbtion in 43% of the stones) than the breccia diamonds (8% non-resorbed stones). In both suites, only 21-24% show high degrees of resorption. The majority of crystals in both suites are colourless, with some yellow, brown and grey stones. Conglomerate diamonds had a wider variety of colours that were not seen in the breccia diamonds, including green and pink. The breccia diamonds contain 0-740 ppm N and show two modes of N aggregation at 0-30 and 60-95%. Among the breccia diamonds, Type IaA stones comprise 17%, whereas IaAB stones make up 49% of the

  19. Hanford basalt flow mineralogy

    International Nuclear Information System (INIS)

    Mineralogy of the core samples from five core wells was examined in some detail. The primary mineralogy study included an optical examination of polished mounts, photomicrographs, chemical analyses of feldspars, pyroxenes, metallic oxides and microcrystalline groundmasses and determination from the chemical analyses of the varieties of feldspars, pyroxenes and metallic oxides. From the primary mineralogy data, a firm understanding of the average Hanford basalt flow primary mineralogy emerged. The average primary feldspar was a laboradorite, the average pyroxene was an augite and the average metallic oxide was a solid solution of ilmenite and magnetite. Secondary mineralization consisted of vug filling and joint coating, chiefly with a nontronite-beidellite clay, several zeolites, quartz, calcite, and opal. Specific flow units also were examined to determine the possibility of using the mineralogy to trace flows between core wells. These included units of the Pomona, the Umatilla and a high chromium flow just below the Huntzinger. In the Umatilla, or high barium flow, the compositional variation of the feldspars was unique in range. The pyroxenes in the Pomona were relatively highly zoned and accumulated chromium. The high chromium flow contained chromium spinels that graded in chromium content into simple magnetites very low in chromium content. A study of the statistical relationships of flow unit chemical constituents showed that flow unit constituents could be roughly correlated between wells. The probable cause of the correlation was on-going physical-chemical changes in the source magma

  20. Sm-Nd dating of Fig Tree clay minerals of the Barberton greenstone belt, South Africa

    Science.gov (United States)

    Toulkeridis, T.; Goldstein, S. L.; Clauer, N.; Kroner, A.; Lowe, D. R.

    1994-01-01

    Sm-Nd isotopic data from carbonate-derived clay minerals of the 3.22-3.25 Ga Fig Tree Group, Barberton greenstone belt, South Africa, form a linear array corresponding to an age of 3102 +/- 64 Ma, making these minerals the oldest dated clays on Earth. The obtained age is 120-160 m.y. younger than the depositional age determined by zircon geochronology. Nd model ages for the clays range from approximately 3.39 to 3.44 Ga and almost cover the age variation of the Barberton greenstone belt rocks, consistent with independent evidence that the clay minerals are derived from material of the belt. The combined isotopic and mineralogical data provide evidence for a cryptic thermal overprint in the sediments of the belt. However, the highest temperature reached by the samples since the time of clay-mineral formation was <300 degrees C, lower than virtually any known early Archean supracrustal sequence.

  1. Aspects of the Petrology and Geochemistry of Greenstones: with special reference to SW England and Wales

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    P.A. Floyd

    2009-09-01

    Full Text Available The use of texture, petrology and geochemistry of Neolithic greenstone hand axes, to determine provenance, is well established. However, as many UK greenstones are essentially meta-dolerites (mildly metamorphosed medium-grained basic rocks it is often necessary to consider the type and degree of alteration superimposed on the primary igneous mineralogy to establish different petrological groups of axes. In particular, alteration and texture can be highly variable in any one large outcrop that might have been used for the manufacture of axes. Similarly, geochemical fingerprinting of axes and subsequent comparison with known outcrops will only be successful if sufficient chemical data are available from any suspected source region when the full range of natural variation has been ascertained.

  2. The Murchison Greenstone Belt, South Africa: Accreted slivers with contrasting metamorphic conditions

    OpenAIRE

    Block, Sylvain; Moyen, Jean-François; Zeh, Armin; Poujol, Marc; Jaguin, Justine; Paquette, Jean-Louis

    2013-01-01

    This paper presents new petrological and geochronological data for the ∼3.09-2.92 Ga Murchison Greenstone Belt (MGB), located in South Africa's Kaapvaal Craton, and discusses their geotectonic implications. The MGB is made of three tectono-metamorphic units: the Silwana Amphibolites, the Murchison Unit and the La France Formation. They underwent contrasting clockwise pressure-temperature-deformation (P-T-D) histories, and are separated from each other by relatively narrow, high-strain shear z...

  3. GREENSTONE OPEN SOURCE DIGITAL LIBRARY SOFTWARE IN THE CONTEXT OF ARABIC CONTENT

    OpenAIRE

    Ramadan Elaiess

    2012-01-01

    The aim of this paper is to explore Greenstone open source digital library software which considered to be one of most essential open-source Content Management Systems (CMSs) that are available for use in creating, organizing, and managing Arabic content on the Internet. It focuses on the appropriateness of the system for Arabic content from different perspectives, such as its ability to support the Arabic language and to sustain and maintain different file formats. It also aims to examine Gr...

  4. Review of tungsten mineralisation in greenstone belts in the eastern and north-eastern Transvaal

    International Nuclear Information System (INIS)

    Tungsten (scheelite) mineralisation is known to occur, occasionally as noteworthy deposits, in the Swazian greenstone belts in the Eastern and North-Eastern Transvaal. An outline and description are given of all known scheelite occurrence in the Sutherland and Murchison Ranges and possibilities of finding such mineralisation in the Barberton greenstone belt are described. Scheelite deposits in these environments: (i) are commonly associated with gold and/or antimony mineralisation; (ii) although found in a variety of host types, commonly occur in amphibolitic and siliceous carbonate rocks; (iii) are found in host rocks belonging to widely separated stratigraphic units in the greenstone belt succession; (iv) display no obviously consistent genetic associations; (v) are typically weakly mineralised. Attention is drawn to the recently postulated theory that tungsten, and spatially related antimony and mercury, mineralisation in the Murchison Range owes its origin to syngenetic processes of concentration, the implications of which, may prove to be important to future investigations. All indications are, however, that the mineralisation is not characterised by any one particular mode of occurrence and that it may not be all of the same age and origin. All known scheelite deposits in the region under review have thus far proved to be of little economic importance

  5. The origin of late archaean granitoids in the Sukuma land greenstone belt of northern Tanzania: Geochemical and isotopic constraints

    International Nuclear Information System (INIS)

    Granitoids intruding the late Archaean sequences of the Sukumaland Greenstone Belt of northern Tanzania belong to two distinct geochemical suites. Suite 1 is characterised by Na2O/K2O > 1 (1.04 - 4.67), high Sr/Y (56 - 204) and Ba/Rb ratios (6.1 - 27.1) and low Rb/Sr ratios (0.08 - 0.25). The rocks are enriched in Sr (405 - 1264 ppm) and depleted in Yb (0.17 - 0.93 ppm) and Rb (56 -132 ppm). On chondrite-normalised REE diagrams, the rocks display highly fractionated patterns characterised by relative LREE enrichment ((La/Yb)N = 23 - 128 and (Gd/Yb)N = 3.10- 8.54) and lower concentrations of the HREE (YbN = 0.80 - 4.45). On primitive mantle-normalised spidergrams, Nb and Ti, together with P and Y are depleted relative to adjacent elements. The major and trace element characteristics of Suite 1 are comparable to those of typical Archaean TTG suites and High Silica Adakites (HSA). Suite 2 granitoids are characterised by Na2O/K2O N = 15 -86 and (Gd/Yb)N = 1.73 - 6.74) and are characterised by higher concentrations of the HREE (YbN = 2.1 - 6.5). On primitive mantle-normalised spidergrams, Suite 2 samples, like those of Suite 1, show relative depletion in Th, Nb and Ti, together with P and Y relative to adjacent elements. Sm-Nd mean crustal residence ages for both suites are indistinguishable and range between 2470 and 2720 Ma with a mean of 2610 ± 35 Ma (2 SE), similar to the emplacement age of 2620 ± 40 Ma. The granitoids are interpreted to have formed by partial melting at the base of a late Archaean thickened sub-arc basaltic crust. Melting to form the Suite 1 granitoids occurred in the eclogite stability field whereas Suite 2 formed by melting at shallower depth in the garnet amphibolite stability field. (author)

  6. Bubble Growth in Lunar Basalts

    Science.gov (United States)

    Zhang, Y.

    2009-05-01

    Although Moon is usually said to be volatile-"free", lunar basalts are often vesicular with mm-size bubbles. The vesicular nature of the lunar basalts suggests that they contained some initial gas concentration. A recent publication estimated volatile concentrations in lunar basalts (Saal et al. 2008). This report investigates bubble growth on Moon and compares with that on Earth. Under conditions relevant to lunar basalts, bubble growth in a finite melt shell (i.e., growth of multiple regularly-spaced bubbles) is calculated following Proussevitch and Sahagian (1998) and Liu and Zhang (2000). Initial H2O content of 700 ppm (Saal et al. 2008) or lower is used and the effect of other volatiles (such as carbon dioxide, halogens, and sulfur) is ignored. H2O solubility at low pressures (Liu et al. 2005), concentration-dependent diffusivity in basalt (Zhang and Stolper 1991), and lunar basalt viscosity (Murase and McBirney 1970) are used. Because lunar atmospheric pressure is essentially zero, the confining pressure on bubbles is completely supplied by the overlying magma. Due to low H2O content in lunar basaltic melt (700 ppm H2O corresponds to a saturation pressure of 75 kPa), H2O bubbles only grow in the upper 16 m of a basalt flow or lake. A depth of 20 mm corresponds to a confining pressure of 100 Pa. Hence, vesicular lunar rocks come from very shallow depth. Some findings from the modeling are as follows. (a) Due to low confining pressure as well as low viscosity, even though volatile concentration is very low, bubble growth rate is extremely high, much higher than typical bubble growth rates in terrestrial melts. Hence, mm-size bubbles in lunar basalts are not strange. (b) Because the pertinent pressures are so low, bubble pressure due to surface tension plays a main role in lunar bubble growth, contrary to terrestrial cases. (c) Time scale to reach equilibrium bubble size increases as the confining pressure increases. References: (1) Liu Y, Zhang YX (2000) Earth

  7. Strength of Concrete Containing Basalt Fibre

    Directory of Open Access Journals (Sweden)

    Parvez Imraan Ansari

    2015-04-01

    Full Text Available This paper presents the comparative study of effect of basalt fibre on compressive and split tensile strength of M40 grade concrete. The basalt fibre was mixed in concrete by (0.5%, 1%, and 1.5% of its total weight of cement in concrete. Results indicated that the strength increases with increase of basalt fibre content up to 1.0% beyond that there is a reduction in strength on increasing basalt fibre. The results show that the concrete specimen with 1.0% of basalt fibre gives better performance when it compared with 0.5%and 1.5% basalt fibre mix in concrete specimens.

  8. The basalts of Mare Frigoris

    Science.gov (United States)

    Kramer, G. Y.; Jaiswal, B.; Hawke, B. R.; Öhman, T.; Giguere, T. A.; Johnson, K.

    2015-10-01

    This paper discusses the methodology and results of a detailed investigation of Mare Frigoris using remote sensing data from Clementine, Lunar Prospector, and Lunar Reconnaissance Orbiter, with the objective of mapping and characterizing the compositions and eruptive history of its volcanic units. With the exception of two units in the west, Mare Frigoris and Lacus Mortis are filled with basalts having low-TiO2 to very low TiO2, low-FeO, and high-Al2O3 abundances. These compositions indicate that most of the basalts in Frigoris are high-Al basalts—a potentially undersampled, yet important group in the lunar sample collection for its clues about the heterogeneity of the lunar mantle. Thorium abundances of most of the mare basalts in Frigoris are also low, although much of the mare surface appears elevated due to contamination from impact gardening with the surrounding high-Th Imbrium ejecta. There are, however, a few regional thorium anomalies that are coincident with cryptomare units in the east, the two youngest mare basalt units, and some of the scattered pyroclastic deposits and volcanic constructs. In addition, Mare Frigoris lies directly over the northern extent of the major conduit for a magma plumbing system that fed many of the basalts that filled Oceanus Procellarum, as interpreted by Andrews-Hanna et al. (2014) using data from the Gravity Recovery and Interior Laboratory mission. The relationship between this deep-reaching magma conduit and the largest extent of high-Al basalts on the Moon makes Mare Frigoris an intriguing location for further investigation of the lunar mantle.

  9. Temperature dependence of basalt weathering

    Science.gov (United States)

    Li, Gaojun; Hartmann, Jens; Derry, Louis A.; West, A. Joshua; You, Chen-Feng; Long, Xiaoyong; Zhan, Tao; Li, Laifeng; Li, Gen; Qiu, Wenhong; Li, Tao; Liu, Lianwen; Chen, Yang; Ji, Junfeng; Zhao, Liang; Chen, Jun

    2016-06-01

    The homeostatic balance of Earth's long-term carbon cycle and the equable state of Earth's climate are maintained by negative feedbacks between the levels of atmospheric CO2 and the chemical weathering rate of silicate rocks. Though clearly demonstrated by well-controlled laboratory dissolution experiments, the temperature dependence of silicate weathering rates, hypothesized to play a central role in these weathering feedbacks, has been difficult to quantify clearly in natural settings at landscape scale. By compiling data from basaltic catchments worldwide and considering only inactive volcanic fields (IVFs), here we show that the rate of CO2 consumption associated with the weathering of basaltic rocks is strongly correlated with mean annual temperature (MAT) as predicted by chemical kinetics. Relations between temperature and CO2 consumption rate for active volcanic fields (AVFs) are complicated by other factors such as eruption age, hydrothermal activity, and hydrological complexities. On the basis of this updated data compilation we are not able to distinguish whether or not there is a significant runoff control on basalt weathering rates. Nonetheless, the simple temperature control as observed in this global dataset implies that basalt weathering could be an effective mechanism for Earth to modulate long-term carbon cycle perturbations.

  10. Spherule Beds 3.47-3.24 Billion Years Old in the Barberton Greenstone Belt, South Africa: A Record of Large Meteorite Impacts and Their Influence on Early Crustal and Biological Evolution

    Science.gov (United States)

    Lowe, Donald R.; Byerly, Gary R.; Kyte, Frank T.; Shukolyukov, Alexander; Asaro, Frank; Krull, Alexander

    2003-01-01

    Four layers, S1-S4, containing sand-sized spherical particles formed as a result of large meteorite impacts, occur in 3.47-3.24 Ga rocks of the Barberton Greenstone Belt, South Africa. Ir levels in S3 and S4 locally equal or exceed chondritic values but in other sections are at or only slightly above background. Most spherules are inferred to have formed by condensation of impact-produced rock vapor clouds, although some may represent ballistically ejected liquid droplets. Extreme Ir abundances and heterogeneity may reflect element fractionation during spherule formation, hydraulic fractionation during deposition, and/or diagenetic and metasomatic processes. Deposition of S1, S2, and S3 was widely influenced by waves and/or currents interpreted to represent impact-generated tsunamis, and S1 and S2 show multiple graded layers indicating the passage of two or more wave trains. These tsunamis may have promoted mixing within a globally stratified ocean, enriching surface waters in nutrients for biological communities. S2 and S3 mark the transition from the 300-million-year-long Onverwacht stage of predominantly basaltic and komatiitic volcanism to the late orogenic stage of greenstone belt evolution, suggesting that regional and possibly global tectonic reorganization resulted from these large impacts. These beds provide the oldest known direct record of terrestrial impacts and an opportunity to explore their influence on early life, crust, ocean, and atmosphere. The apparent presence of impact clusters at 3.26-3.24 Ga and approx. 2.65-2.5 Ga suggests either spikes in impact rates during the Archean or that the entire Archean was characterized by terrestrial impact rates above those currently estimated from the lunar cratering record.

  11. Ultramafic parent magmas for mare basalts

    International Nuclear Information System (INIS)

    Solidification products of basaltic magmas (fine grained basalts and ultramafic glasses) at the Apollo 15 site were examined. Consideration of simple MgO-6IO2-Al2O3 systematics plus results of calculations of fractional crystallization was reviewed. Suggestions are presented to account for the lack of correlation between the ultramafic glasses and basalts

  12. Geology of East Egypt greenstone field in Neoproterozoic isoand arc: Reconstruction of Iron formation sedimentary environment.

    Science.gov (United States)

    Kiyokawa, S.; Suzuki, T.

    2015-12-01

    Geology of East Egypt greenstone-granit belt which is northern part of Nubia shield was identified neoproterozoic island arc amalgamated sections. There are several iron formation within these greenstone belt. Age data shows this iron formation may be overlaped during 700 Ma Snowball period, how ever, there is no detail report of well preserved ice related evidences. We now started detail field work for identified tectonic reconstruction, original stratigraphy around Iron formation and sedimentary environment during the iron formation sedimentation area. East Egyptian shield was divided three geology, Proterozoic greenstone complex, 700-600 Granitic domes and cover sequence (Hammamet Group). We focus three area to identified sedimentary environment of iron sedimentation. Along the north-south trend of Wadi EL Dabban area are, we named Wadi branch as West site is RW-0 ~ 12, East site is RE-0 ~ 12 from north to south. Northern area is structurally moderate, southern portion is north dipping. Southern portion was intruded by granite and several place contain granitic dikes. Northeast to eastern area are identified younger sedimentary sequence (Hammamat Group) which is unconformablly overlay on the other iron formation bearing greenstone belt. Structurally these area is divided four units. Wadi was divided by right-lateral strike-ship fault. The displacement are more than 3 km. Also north dipping faults are identified.East-West trend fault are divided two units. It is divided NE, SE, NW and NS units.SW unit is most well preserved thick sequence of the Iron formation. SW unit is well preserved iron formation sequence within thick volcaniclastics. This unit mostly north dipping around 40-60 degree. Structural repetition in not well understand. Reconstract stratigraphy in this unit is at least 4000m in thickness. 5 member is identified in this sequence. Several thin iron formations are observed with in pillow lava and volcaniclastic sequence. These very thick

  13. Scheelite distribution a long of amphibolitic belt from greenstone belt Barbacena, Minas Gerais, Brazil

    International Nuclear Information System (INIS)

    In the middle southern portion of the Minas Gerais state a 60 Km long and 12 Km wide tungsten belt was discovered, and related to the amphibolitic rocks of the Barbacena Greenstone. Tungsten, present as scheelite, is associated with amphibolites, amphibole schists and amphibole gneisses, with chemical characteristics indicating an igneous origin. Chemical analyses on pan concentrates by I.C.P. showed high values on lead, tin, yttrium, lanthanum, cerium and zirconium, and average values for zinc and copper. The scheelite mineralization is probably strata bound and has a possible submarine exhalative origin. (author)

  14. Permeability within basaltic oceanic crust

    Science.gov (United States)

    Fisher, Andrew T.

    1998-05-01

    Water-rock interactions within the seafloor are responsible for significant energy and solute fluxes between basaltic oceanic crust and the overlying ocean. Permeability is the primary hydrologic property controlling the form, intensity, and duration of seafloor fluid circulation, but after several decades of characterizing shallow oceanic basement, we are still learning how permeability is created and distributed and how it changes as the crust ages. Core-scale measurements of basaltic oceanic crust yield permeabilities that are quite low (generally 10-22 to 10-17 m²), while in situ measurements in boreholes suggest an overlapping range of values extending several orders of magnitude higher (10-18 to 10-13 m²). Additional indirect estimates include calculations made from borehole temperature and flow meter logs (10-16 to 10-11 m²), numerical models of coupled heat and fluid flow at the ridge crest and within ridge flanks (10-16 to 10-9 m²), and several other methods. Qualitative indications of permeability within the basaltic oceanic crust come from an improved understanding of crustal stratigraphy and patterns of alteration and tectonic modification seen in ophiolites, seafloor samples and boreholes. Difficulties in reconciling the wide range of estimated permeabilities arise from differences in experimental scale and critical assumptions regarding the nature and distribution of fluid flow. Many observations and experimental and modeling results are consistent with permeability varying with depth into basement and with primary basement lithology. Permeability also seems to be highly heterogeneous and anisotropic throughout much of the basaltic crust, as within crystalline rocks in general. A series of focused experiments is required to resolve permeability in shallow oceanic basement and to directly couple upper crustal hydrogeology to magmatic, tectonic, and geochemical crustal evolution.

  15. Thermoluminescence dating of Hawaiian basalt

    Science.gov (United States)

    May, Rodd James

    1979-01-01

    The thermoluminescence (TL) properties of plagioclase separates from 11 independently dated alkalic basalts 4,500 years to 3.3 million years old and 17 tholeiitic basalts 16 years to 450,000 years old from the Hawaiian Islands were investigated for the purpose of developing a TL dating method for young volcanic rocks. Ratios of natural to artificial TL intensity, when normalized for natural radiation dose rates, were used to quantify the thermoluminescence response of individual samples for age-determination purposes. The TL ratios for the alkalic basalt plagioclase were found to increase with age at a predictable exponential rate that permits the use of the equation for the best-fit line through a plot of the TL ratios relative to known age as a TL age equation. The equation is applicable to rocks ranging in composition from basaltic andesite to trachyte over the age range from about 2,000 to at least 250,000 years before present (B.P.). The TL ages for samples older than 50,000 years have a calculated precision of less than :t 10 percent and a potential estimated accuracy relative to potassium-argon ages of approximately :t 10 percent. An attempt to develop a similar dating curve for the tholeiitic basalts was not as successful, primarily because the dose rates are on the average lower than those for the alkalic basalts by a factor of 6, resulting in lower TL intensities in the tholeiitic basalts for samples of equivalent age, and also because the age distribution of dated material is inadequate. The basic TL properties of the plagioclase from the two rock types are similar, however, and TL dating of tholeiitic basalts should eventually be feasible over the age range 10,000 to at least 200,000 years B.P. The average composition of the plagioclase separates from the alkalic basalts ranges from oligoclase to andesine; compositional variations within this range have no apparent effect on the TL ratios. The average composition of the plagioclase from the tholeiitic

  16. The provenance and Sm/Nd Model ages of siliciclastic supracrustal rocks of the Faina and Santa Rita Greenstone belts, Goias, Brazil

    International Nuclear Information System (INIS)

    The Faina and Santa Rita greenstone belts are two N 60 deg C W trending synclinoria separated by a N 30 deg C E strike-slip fault and rest allochtonous on the adjacent Uva and Caicara granite-gneiss complexes. The belts are made up of lower metakomatiites, followed by metabasalts and thick metasedimentary sequences deposited under contrasting paleogeographic settings. In Faina, the sequence consists of two complete shelf cycles, the first resting on basalts by an erosional unconformity. In Santa Rita, the basalts give gradually place to carbonaceous metashales, unconformably overlain by metarhythmites. Provenance based on trace element geochemistry, mineral chemistry of chloride and muscovite, source-are modeling and REE elements indicate that protoliths of the first shelf cycle of Faina and the carbonaceous metashales of Santa Rita formed under the influence of a source area dominated by mafic ultramafic rocks, whilst during the sedimentation of the second shelf cycle and the metarhythmites of Santa Rita the source-area was dominated by TTG granitoids. Sm-Nd model ages of the lower sedimentary packages vary between 3.0 and 2.8 Ga and the upper between 2.7 and 2.6 Ga. These intervals coincide, respectively, with the estimated age of the underlying, and with the Sm-Nd, Rb-Sr e U-Pb ages of the main granitoids and gneisses of the adjacent complexes. The same data indicate that, during the sedimentation of the first shelf cycle of Faina and the carbonaceous metashales of Santa Rita, both basins had independent source-areas, but shared the same source during the upper sections. Weathering nature and intensity of the source-area calculated by means of geochemical a data suggest that the dramatic change of provenance from the lower to the upper sections is due to the shift from tectonically stable to unstable regimes, interpreted as resulting from the emergence of the island arc whose roots are represented by the adjacent granite-gneiss complexes. (author)

  17. The structural history and mineralization controls of the world-class Geita Hill gold deposit, Geita Greenstone Belt, Tanzania

    Science.gov (United States)

    Sanislav, I. V.; Brayshaw, M.; Kolling, S. L.; Dirks, P. H. G. M.; Cook, Y. A.; Blenkinsop, T. G.

    2016-05-01

    The Geita Hill gold deposit is located in the Archean Geita Greenstone Belt and is one of the largest gold deposits in East Africa. The Geita Greenstone Belt experienced a complex deformation and intrusive history that is well illustrated and preserved in and around the Geita Hill gold deposit. Deformation involved early stages of ductile shearing and folding (D1 to D5), during which episodic emplacement of large diorite intrusive complexes, sills, and dykes occurred. These ductile deformation phases were followed by the development of brittle-ductile shear zones and faults (D6 to D8). The last stages of deformation were accompanied by voluminous felsic magmatism involving the intrusion of felsic porphyry dykes, within the greenstone belt, and the emplacement of large granitic bodies now forming the margins of the greenstone belt. Early, folded lamprophyre dykes, and later lamprophyre dykes, crosscutting the folded sequence are common, although volumetrically insignificant. The gold deposit formed late during the tectonic history of the greenstone belt, post-dating ductile deformation and synchronous with the development of brittle-ductile shear zones that overprinted earlier structural elements. The main mineralizing process involved sulfide replacement of magnetite-rich layers in ironstone and locally the replacement of ferromagnesian phases and magnetite in the diorite intrusions. The intersection between the brittle-ductile (D6) Geita Hill Shear Zone and different structural elements of ductile origin (e.g., fold hinges), and the contact between banded ironstone and folded diorite dykes and sills provided the optimal sites for gold mineralization.

  18. The stratigraphy of the 3.5-3.2 Ga Barberton Greenstone Belt revisited: A single zircon ion microprobe study

    International Nuclear Information System (INIS)

    Recent field and geochemical studies indicate a need to test the stratigraphy of the ca. 3.5 Ga Barberton Greenstone Belt as it is presently adopted. This work uses the ion microprobe SHRIMP, to attempt such a test. Results show that: (1) Volcaniclastic sediments of the Theespruit Formation (<3453±6 Ma) could be younger than the (structurally) overlying mafic and ultramafic volcanics of the Komati Formation (3482±5 Ma). A major structural discontinuity may therefore exist between the two formations. (2) An age of 3538±6 Ma established for a tectonic wedge of tonalitic gneiss within the Theespruit Formation confirms the presence of a sialic basement and deformed unconformity below that unit. The tonalitic gneiss is the oldest unit yet recorded within the greenstone belt, equal in age to the older components of the adjacent Ancient Gneiss Complex. (3) The interpreted ages of felsic volcanic rocks from both the Hooggenoeg (3445±8 Ma) and Theespruit Formations and the nearby Theespruit Pluton (3437±6 Ma) are essentially the same, and corroborate field and geochemical evidence that the felsic units were probably cogenetic and emplaced simultaneously as high-level equivalents of trondjhemite-tonalite plutons that intrude the greenstone belt at its southwestern extremity. (4) Felsic-intermediate volcanic-volcaniclastic rocks locally separating the two major groups (the Fig Tree and Moodies Groups) which overlie the Onverwacht Group record a second major peak of tonalitic magmatism in the Barberton terrain at about 3250 Ma. This is close to the age of the Kaap Valley tonalite pluton which intrudes the Barberton Greenstone Belt at ca. 3226 Ma along its northwestern margin. The present results indicate the Barberton Greenstone Belt is part of an allochthonous sequence containing major tectonic and stratigraphic breaks, with a protracted history; of which the last 200 million years, at least, evolved within a tectonically active convergent environment. (orig.)

  19. Technical Assessment of Greenstone toward Development of Digital Libraries in Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Hassanzadeh

    2012-03-01

    Full Text Available Lack of integrated software is serious obstacle toward the development of digital libraries in Iran. Considering the problem, this research focused on Greenstone digital library software (GDLS to investigate its technical capabilities toward creating and managing digital collections in Iranian libraries. The study was conducted through evaluation research using a 9-spectrums checklist in two phases. In the first stage, experts from library and information science and computer science and in second stage, three user groups (with PhD, MA and BA degrees completed the checklist against capabilities of GDLS. Findings indicated that, there was no significant difference between two groups of specialist about capabilities of GDLS. Analyzing three user groups also approved GDLS competencies at this respect. There were some technical errors and bugs that experts proposed to be corrected toward best fitness of GDLS to Iranian collections.

  20. Micro-PIXE elemental imaging of pyrites from the Bulawayan-Bubi Greenstone Belt, Zimbabwe

    International Nuclear Information System (INIS)

    Micro-PIXE at the NAC nuclear microprobe was used for studies of a sequence of unusual pyrite-bearing carbonate sediments from the east of Turk Mine, Bubi Greenstone Belt, Zimbabwe. This pyrite mineralization shows a variety of textures, and its petrographic interpretation needed more solid geochemical evidence. Elemental maps were obtained using Dynamic Analysis (DA) (a rapid matrix transform method) which forms part of the GeoPIXE software package, and were complemented by point analyses in selected areas. The implemented on-demand beam deflection system allowed for count rates of the order of 3000 counts/s with negligible dead time. The distribution of As and other elements confirmed the petrographic interpretation of three different pyrite generations. In addition, point analyses showed that Sb and Pb were significantly elevated in the zones of As enrichment

  1. Geotectonic evolution of granitoid-greenstone belts from Crixas, Guarinos, Pilar de Goias - Hidrolina (Goias), Brazil

    International Nuclear Information System (INIS)

    The area in discussion, in a geologic context, constitutes one of the most interesting and complex, within the South American Platform, in Brazilian territory, over which granitoid-greenstone belts are outstanding. The Goiano Complex is the oldest unit in the geologic column herein adopted and composed largely of granitoids, gneiss and migmatites, in the amphibolite facies. Dated samples of the complex have shown two isochrones of Rb/Sr reference, the oldest one is 2.926 +- 65 m.y. and the 87 Sr/86 Sr initial ratio of 0.7001 and the youngest on of 2.471 + 20 m.y. and 87 Sr/86 Sr initial ratio of 0.701. Although the initial ratios data of the Rb/Sr isochron, as well as the parameters in the Pb/Pb analyses may indicate material of mantle source, it may be interpreted, with the help of field data, that the youngest values may indicate the reworking of crustal sialic rocks formed 2.925 +- 65 m.y. ago (oldest isochron), with primitive material contribution. Before such reworking volcanic-sedimentary sequence was deposited over the already formed sialic crust, and it is denominated Pilar de Goias Supergroup which characterizes the Greenstone Belts in the region. The Archean age for the supergroup was evident through the age results of its ultramafic rocks, showing 2.600 m.y. isochron age, with Sm/Nd methods. Besides the geochronology and field studies, basic information for the construction of the geologic column herein presented, there has been done petrographic and litho geochemical studies, both in the Goiano Complex and Pilar de Goias Supergroup, as for the Pilar de Goias Supergroup, the studies were concentrated on its mafic-ultramafic rocks. (author)

  2. Basaltic cannibalism at Thrihnukagigur volcano, Iceland

    Science.gov (United States)

    Hudak, M. R.; Feineman, M. D.; La Femina, P. C.; Geirsson, H.

    2014-12-01

    Magmatic assimilation of felsic continental crust is a well-documented, relatively common phenomenon. The extent to which basaltic crust is assimilated by magmas, on the other hand, is not well known. Basaltic cannibalism, or the wholesale incorporation of basaltic crustal material into a basaltic magma, is thought to be uncommon because basalt requires more energy than higher silica rocks to melt. Basaltic materials that are unconsolidated, poorly crystalline, or palagonitized may be more easily ingested than fully crystallized massive basalt, thus allowing basaltic cannibalism to occur. Thrihnukagigur volcano, SW Iceland, offers a unique exposure of a buried cinder cone within its evacuated conduit, 100 m below the main vent. The unconsolidated tephra is cross-cut by a NNE-trending dike, which runs across the ceiling of this cave to a vent that produced lava and tephra during the ~4 Ka fissure eruption. Preliminary petrographic and laser ablation inductively coupled mass spectrometry (LA-ICP-MS) analyses indicate that there are two populations of plagioclase present in the system - Population One is stubby (aspect ratio 2.1), subhedral to euhedral, and has much higher Ba/Sr ratios. Population One crystals are observed in the cinder cone, dike, and surface lavas, whereas Population Two crystals are observed only in the dike and surface lavas. This suggests that a magma crystallizing a single elongate population of plagioclase intruded the cinder cone and rapidly assimilated the tephra, incorporating the stubbier population of phenocrysts. This conceptual model for basaltic cannibalism is supported by field observations of large-scale erosion upward into the tephra, which is coated by magma flow-back indicating that magma was involved in the thermal etching. While the unique exposure at Thrihnukagigur makes it an exceptional place to investigate basaltic cannibalism, we suggest that it is not limited to this volcanic system. Rather it is a process that likely

  3. Status report: working group on the controls of mineralization in granite-greenstone terraines of the Kaapvaal Craton

    International Nuclear Information System (INIS)

    This report summarize the activities of the working group on the controls of mineralization in Granite-Greenstone terraines of the Kaapvaal Craton. Some ore deposits in this granite-greenstone terraines have a strong affinity with those formed in modern ocean floor environments and others are associated with felsic volcanic rocks similar to those in modern island arc and Andean-type systems. Most of the deposits, however have been affected by tectonic and metamorphic processes leading to the formation of the craton. These craton forming processes have determined the present disposition of the ore bodies and have been responsible for concentrating elements such as Au and Sb into economically viable ore bodies

  4. The rheological behaviour of fracture-filling cherts: example of Barite Valley dikes, Barberton Greenstone Belt, South Africa

    OpenAIRE

    M. Ledevin; Arndt, N.; Davaille, A.; Ledevin, R.; Simionovici, A.

    2015-01-01

    In the Barberton Greenstone Belt, South Africa, a 100–250 m thick complex of carbonaceous chert dikes marks the transition from the Mendon Formation to the Mapepe Formation (3260 Ma). The sub-vertical- to vertical position of the fractures, the abundance of highly shattered zones with poorly rotated angular fragments and common jigsaw fit, radial structures, and multiple injection features point to repetitive hydraulic fracturing that released overpressured fluids trapped wi...

  5. The rheological behavior of fracture-filling cherts: example of Barite Valley dikes, Barberton Greenstone Belt, South Africa

    OpenAIRE

    M. Ledevin; Arndt, N.; Simionovici, A.

    2014-01-01

    A 100 m-thick complex of near-vertical carbonaceous chert dikes marks the transition from the Mendon to Mapepe Formations (3260 Ma) in the Barberton Greenstone Belt, South Africa. Fracturing was intense in this area, as shown by the profusion and width of the dikes (ca. 1 m on average) and by the abundance of completely shattered rocks. The dike-and-sill organization of the fracture network and the upward narrowing of some of the large veins indicate that at...

  6. Single zircon ages for felsic to intermediate rocks from the Pietersburg and Giyani greenstone belts and bordering granitoid orthogneisses, northern Kaapvaal Craton, South Africa

    Science.gov (United States)

    Kröner, A.; Jaeckel, P.; Brandl, G.

    2000-05-01

    Previous models for the temporal evolution of greenstone belts and surrounding granitoid gneisses in the northern Kaapvaal Craton can be revised on the basis of new single zircon ages, obtained by conventional UPb dating and PbPb evaporation. In the Pietersburg greenstone belt, zircons from a metaquartz porphyry of the Ysterberg Formation yielded an age of 2949.7±0.2 Ma, while a granite intruding the greenstones, and deformed together with them, has an age of 2853 + 19/-18 Ma. These data show felsic volcanism in this belt to have been coeval with felsic volcanism in the Murchison belt farther east, and the date of ˜2853 Ma provides an older age limit for deformation in the region. In contrast, a meta-andesite of the Giyani greenstone belt has a zircon age of 3203.3±0.2 Ma, while a younger and cross-cutting feldspar porphyry has an emplacement age of 2874.1±0.2 Ma. The meta-andesite is intercalated with various mafic and ultramafic rocks and, therefore, the age of 3.2 Ga appears plausible for the bulk of the Giyani greenstones. Granitoid gneisses surrounding the Pietersburg and Giyani belts vary in composition from tonalite to granite and texturally from well-layered to homogeneous but strongly foliated. These rocks yielded zircon ages between 2811 and 3283 Ma. The pre-3.2 Ga gneisses are polydeformed and may have constituted a basement to the Giyani greenstone sequence, while the younger gneisses are intrusive into the older gneiss assemblage and/or into the greenstones. The Giyani and Pietersburg belts probably define two separate crustal entities that were originally close together but were later displaced by strike-slip movement.

  7. Mesoarchean sanukitoid rocks of the Rio Maria Granite-Greenstone Terrane, Amazonian craton, Brazil

    Science.gov (United States)

    de Oliveira, Marcelo Augusto; Dall'Agnol, Roberto; Althoff, Fernando Jacques; da Silva Leite, Albano Antonio

    2009-02-01

    The Archean sanukitoid Rio Maria Granodiorite yielded zircon ages of ˜2.87 Ga and is exposed in large domains of the Rio Maria Granite-Greenstone Terrane, southeastern Amazonian craton. It is intrusive in the greenstone belts of the Andorinhas Supergroup, in the Arco Verde Tonalite and Caracol Tonalitic Complex (older TTGs). Archean potassic leucogranites, younger TTGs and the Paleoproterozoic granites of Jamon Suite are intrusive in the Rio Maria Granodiorite. The more abundant rocks of the Rio Maria Granodiorite have granodioritic composition and display medium to coarse even-grained textures. These rocks show generally a gray color with greenish shades due to strongly saussuritized plagioclase, and weak WNW-ESE striking foliation. The significant geochemical contrasts between the occurrences of Rio Maria Granodiorite in different areas suggest that this unit corresponds in fact to a granodioritic suite of rocks derived from similar but distinct magmas. Mingling processes involving the Rio Maria Granodiorite and similar mafic to intermediate magmas are able to explain the constant occurrence of mafic enclaves in the granodiorite. The associated intermediate rocks occur mainly near Bannach, where mostly quartz diorite and quartz monzodiorite are exposed. The dominant rocks are mesocratic, dark-green rocks, with fine to coarse even-grained texture. The Rio Maria Granodiorite and associated intermediate rocks show similar textural and mineralogical aspects. They follow the calc-alkaline series trend in some diagrams. However, they have high-Mg#, Cr, and Ni conjugate with high contents of large ion lithophile elements (LILEs), typical of sanukitoids series. The patterns of rare earth elements of different rocks are similar, with pronounced enrichment in light rare earth elements (LREEs) and strong to moderate fractionation of heavy rare earth elements (HREEs). Field aspects and petrographic and geochemical characteristics denote that the granodiorites and

  8. Experimental research on continuous basalt fiber and basalt-fibers-reinforced polymers

    Science.gov (United States)

    Zhang, Xueyi; Zou, Guangping; Shen, Zhiqiang

    2008-11-01

    The interest for continuous basalt fibers and reinforced polymers has recently grown because of its low price and rich natural resource. Basalt fiber was one type of high performance inorganic fibers which were made from natural basalt by the method of melt extraction. This paper discusses basic mechanical properties of basalt fiber. The other work in this paper was to conduct tensile testing of continuous basalt fiber-reinforced polymer rod. Tensile strength and stress-strain curve were obtained in this testing. The strength of rod was fairly equal to rod of E-glass fibers and weaker than rod of carbon fibers. Surface of crack of rod was studied. An investigation of fracture mechanism between matrix and fiber was analyzed by SEM (Scanning electron microscopy) method. A poor adhesion between the matrix and fibers was also shown for composites analyzing SEM photos. The promising tensile properties of the presented basalt fibers composites have shown their great potential as alternative classical composites.

  9. Orthopyroxene fractionation in the Grande Ronde Basalt--Columbia River Basalt group

    International Nuclear Information System (INIS)

    Six orthopyroxenes were microprobed; five orthopyroxenes were from the Grande Ronde Basalt, and one was from the Buford flow of the Saddle Mountains Basalt. The orthopyroxenes are primarily bronzite in composition, but some analyses show that hypersthene is present. The reaction rims of all analyzed orthopyroxene crystals are pigeonite, while the groundmass pyroxene is both augite and pigeonite. Preliminary results from the least-squares linear modeling of the Grande Ronde Basalt indicate orthopyroxene is a necessary phase for mass balancing between flow compositions. Three models were tried in order to determine if selected mineral phases could be used to model the chemical compositions of the flows. These models suggest that orthopyroxene and plagioclase are phases common to the Grande Ronde Basalt. The similarity of orthopyroxene and plagioclase occurrences suggests that they are important intratelluric phases of the Grande Ronde Basalt which reacted out when the basaltic liquids were erupted at the surface

  10. Basaltic Soil of Gale Crater: Crystalline Component Compared to Martian Basalts and Meteorites

    Science.gov (United States)

    Treiman, A. H.; Bish, D. L.; Ming, D. W.; Morris, R. V.; Schmidt, M.; Downs, R. T.; Stolper, E. M.; Blake, D. F.; Vaniman, D. T.; Achilles, C. N.; Chipera, S. J.; Bristow, T. F.; Crisp, J. A.; Farmer, J. A.; Morookian, J. M.; Morrison, S. M.; Rampe, E. B.; Sarrazin, P.; Yen, A. S.; Anderosn, R. C.; DesMarais, D. J.; Spanovich, N.

    2013-01-01

    A significant portion of the soil of the Rocknest dune is crystalline and is consistent with derivation from unweathered basalt. Minerals and their compositions are identified by X-ray diffraction (XRD) data from the CheMin instrument on MSL Curiosity. Basalt minerals in the soil include plagioclase, olivine, low- and high-calcium pyroxenes, magnetite, ilmenite, and quartz. The only minerals unlikely to have formed in an unaltered basalt are hematite and anhydrite. The mineral proportions and compositions of the Rocknest soil are nearly identical to those of the Adirondack-class basalts of Gusev Crater, Mars, inferred from their bulk composition as analyzed by the MER Spirit rover.

  11. Albitization and the gold-bearing Roodepoort pluton, Pietersburg granite-greenstone terrane, South Africa

    International Nuclear Information System (INIS)

    The gold bearing Roodepoort pluton in the Pietersburg granite-greenstone terrane of South Africa consists primarily of undeformed albite with lesser amounts of quartz, ankerite, magnesite, and pyrite. The pluton intruded a major N-70 degrees trending shear zone, the Knight's Pietersburg line. The present mineralogy of the pluton and its gold content are essentially secondary, formed by open system hydrothermal alteration. However, relic minerals indicate that the pluton originally had a granodioritic composition. This composition, as well as its initial 87Sr/86Sr ratio, are similar to those of the 2 660 Ma Turfloop batholith and are consistent with the possibility that the Roodepoort pluton is an altered phase of the batholith. Sr isotopic data also suggest that hydrothermal alteration occured shortly after the magmatic crystallization of the pluton. Some alteration along the Knight's Pietersburg line occured about 2 680 Ma ago. It is proposed that the emplacement of the Roodepoort pluton, the hydrothermal alteration and the gold mineralization are related to the Limpopo Orogeny. A second phase of open system hydrothermal alteration occured in shear zones along the margins of and within the Roodepoort pluton, apparently about 2 320 Ma ago. 5 figs., 5 tabs., 27 refs

  12. Archaean hydrothermal zircon in the Abitibi greenstone belt: Constraints on the timing of gold mineralisation

    International Nuclear Information System (INIS)

    Hydrothermal zircons have been found in Archaean mesothermal Au-veins and altered wallrock selvages at Val d'Or, in the Abitibi greenstone belt of Canada. The zircons are paragenetically associated with vein quartz, tourmaline, mica, carbonate, scheelite, pyrite, and gold. Zirconium mobility, and the consequent occurrence of hydrothermal zircon, may be associated with the intense tourmalinisation characteristic of Archaean gold deposits in this district. The SHRIMP ion-microprobe has been used to analyse hydrothermal zircons from four separate mines spatially associated with the Bourlamaque batholith, and has yieleded ages constraining formation of the Au-bearing vein systems to within 20 Ma of emplacement of the pluton. The ion microprobe data reveal multiple stages of hydrothermal zircon growth in the vein systems, contemporaneous with the regional metamorphic peak and late kinematic activity along regional structures. Younger (including Proterozoic) ages previously obtained for the veins, using other minerals and isotopic schemes, must reflect either alteration or renewed mineral growth during much later reactivation of fluids along the same structures up to 400 Ma after initial formation of the veins. (orig.)

  13. Noble Gases and Halogens in Icelandic Basalts

    OpenAIRE

    Weston, Bridget

    2013-01-01

    Noble gas and halogen data from a suite of Icelandic samples are presented. Iceland combines hotspot volcanism, a spreading ridge and abundant subglacially erupted samples. This combination allows for samples that erupted under high enough pressures to retain a measurable mantle volatile content, and also display signatures representing interaction between ocean island basalt (OIB) and mid-ocean ridge basalt (MORB) mantle sources.Erupted samples used to determine the mantle’s halogen and nobl...

  14. Hydrothermal evolution of repository groundwaters in basalt

    International Nuclear Information System (INIS)

    Groundwaters in the near field of a radioactive waste repository in basalt will change their chemical composition in response to reactions with the basalt. These reactions will be promoted by the heat generated by the decaying waste. It is important to predict both the rate and the extent of these reactions, and the secondary minerals produced, because the alteration process controls the chemical environment affecting the corrosion of the canister, the solubility and complexation of migrating radionuclides, the reactivity of the alteration products to radionuclides sorption, and the porosity and permeability of the host rock. A comprehensive review of the literature leads to the preliminary finding that hydrothermally altering basalts in geothermal regions such as Iceland lead to a secondary mineralogy and groundwater composition similar to that expected to surround a repository. Furthermore, laboratory experiments replicating the alteration conditions approximate those observed in the field and expected in a repository. Preliminary estimates were made of the rate of hydration and devitrification of basaltic glass and the zero-order dissolution rate of basaltic materials. The rates were compared with those for rhyolitic glasses and silicate minerals. Preliminary calculations made of mixed process alteration kinetics, involving pore diffusion and surface reaction suggest that at temperatures greater than 1500C, alteration proceeds so rapidly as to become pervasive in normally fractured basalt exposed to higher temperatures in the field. 70 references

  15. Granite-greenstone terranes in the Pilbara Block, Australia, as coeval volcano-plutonic complexes: Evidence from U-Pb zircon dating of the Mount Edgar Batholith

    International Nuclear Information System (INIS)

    The Mount Edgar Batholith in the Pilbara Block, Western Australia, consists, in part, of a gneiss complex that resembles other Archean high-grade gneiss terranes. The complex is extensively intruded by variably foliated granitoids which also intrude the surrounding greenstone succession, the Warrawoona Group. The contact between the greenstone belt and the gneiss complex is tectonic. Field evidence indicates that the banded gneisses are the oldest part of the batholith; zircon U-Pb ages for three samples are 3429±13 Ma, ≥ 3443±10 Ma and 3448±8 Ma, all very similar to the age of zircons in the felsic volcanic rocks near the base of the greenstone succession. Two granitoids, representing pre- and post-tectonic phases respectively, give zircon ages of 3304±10 Ma and 3314±13 Ma, thereby constraining the major structural events to be contemporary with granite magmatism, consistent with a diapiric model for the tectonic evolution of the batholith. These ages are similar to the zircon age for terminal volcanism in the Warrawoona Group, but are ≅ 100 Ma older than the precisely-defined Rb-Sr whole-rock ages obtained throughout the batholith. Batholith-wide resetting or late closure of Rb-Sr isotopic systems is implied, possibly associated with late fluid circulation. The temporal coincidence between plutonism and volcanism in the Mount Edgar region strongly suggests that the greenstone succession contains the extrusive equivalents of both the ≅ 3300 Ma granites and the ≅ 3440 Ma gneisses in the batholith. The isotopic evidence, combined with the structural data, indicates that the granites cannot be derived from the surrounding greenstone belt. Further, there is no compelling evidence for a sialic basement to the greenstone succession. (orig.)

  16. Early terrestrial impact events: Archean spherule layers in the Barberton Greenstone Belt, South Africa

    Science.gov (United States)

    Ozdemir, Seda; Koeberl, Christian; Schulz, Toni; Reimold, W. Uwe; Hofmann, Axel

    2015-04-01

    In addition to the oldest known impact structure on Earth, the 2.02-billion-year-old Vredefort Structure in South Africa, the evidence of Early Earth impact events are Archean spherule beds in South Africa and Australia. These spherules have been interpreted as condensation products from impact plumes and molten impact ejecta or/and impact ejecta that were melted during atmospheric re-entry [e.g., 1,2]. The 3.2-3.5 Ga spherule layers in the Barberton Greenstone Belt in South Africa currently represent the oldest known remnants of impact deposits on Earth. Aiming at identification of extraterrestrial components and to determine the diagenetic and metamorphic history of spherule layer intersections recently recovered in the CT3 drill core from the northeastern part of the Barberton Greenstone Belt, we have studied samples from these layers in terms of petrography and geochemistry. All samples, including spherule layer intersections and intercalating country rocks, were studied for mineral identification by optical and electron microscopy, as well as electron microprobe analysis (EPMA) at Natural History Museum Vienna and Museum für Naturkunde Berlin (MfN). Major and trace element compositions were determined via X-ray fluorescence spectrometry at MfN and instrumental neutron activation analysis (INAA) at University of Vienna. Os isotopes were measured by thermal ionization mass spectrometry (N-TIMS) at University of Vienna. Eighteen spherule beds are distributed over 150 meter drill core in CT3. Spherules are variably, deformed or undeformed. The high number of these layers may have been caused by tectonic duplication. Spherule beds are intercalated with shale, chert, carbonate, and/or sulfide deposits (country rocks). The size range of spherules is 0.5 to 2 mm, and some layers exhibit gradation. Shapes of spherules differ from spherical to ovoid, as well as teardrops, and spherules commonly show off-center vesicles, which have been interpreted as a primary

  17. Radionuclide reactions with groundwater and basalts from Columbia River basalt formations

    International Nuclear Information System (INIS)

    Chemical reactions of radionuclides with geologic materials found in Columbia River basalt formations were studied. The objective was to determine the ability of these formations to retard radionuclide migration from a radioactive waste repository located in deep basalt. Reactions that can influence migration are precipitation, ion-exchange, complexation, and oxidation-reduction. These reactions were studied by measuring the effects of groundwater composition and redox potential (Eh) on radionuclide sorption on fresh basalt surfaces, a naturally altered basalt, and a sample of secondary minerals associated with a Columbia River basalt flow. In addition, radionuclide sorption isotherms were measured for these materials and reaction kinetics were determined. The radionuclides studied were 137Cs, 85Sr, 75Se, /sup 95m/Tc, 237Np, 241Am, 226Ra and 237Pu. The Freundlich equation accurately describes the isotherms when precipitation of radionuclides does not occur. In general, sorption increased in the order: basalt < altered basalt < secondary minerals. This increase in sorption corresponds to increasing surface area and cation exchange capacity. The Eh of the system had a large effect on technetium, plutonium, and neptunium sorption. Technetium(VII), Pu(VI), and Np(V) are reduced to Tc(IV), Pu(IV), and Np(IV), respectively, under Eh conditions expected in deep basalt formations. The kinetics of radionuclide sorption and basalt-groundwater reactions were observed over a period of 18 weeks. Most sorption reactions stabilized after about four weeks. Groundwater composition changed the least in contact with altered basalt. Contact with secondary minerals greatly increased Ca, K, and Mg concentrations in the groundwater

  18. First data on Sm-Nd isotope systematics of the Kholodnikansk greenstone belt metavolcanites, the Southern Aldan shield

    International Nuclear Information System (INIS)

    The age of the Kholodnikansk greenstone metavolcanites, located in the south of the Southern Aldan shield, is determined through the method of the Sm-Nd dating with the purpose of studying its earth crust constituent segments formation. The obtained metavolcanites isochronous age, equal to 2.41±0.08 billion years testifies to the fact, that the processes of the early proterozoic activation (2.2-2.4 billion years ago) were manifested not only within the limits of the Central-Aldan complex but also in the south of the Aldan shield

  19. Isotopic geochronological evidence for the Paleoproterozoic age of gold mineralization in Archean greenstone belts of Karelia, the Baltic Shield

    Science.gov (United States)

    Larionova, Yu. O.; Samsonov, A. V.; Shatagin, K. N.; Nosova, A. A.

    2013-09-01

    The Rb-Sr age of metasomatic rocks from four gold deposits and occurrences localized in Archean granite-greenstone belts of the western, central, and southern Karelian Craton of the Baltic Shield has been determined. At the Pedrolampi deposit in central Karelia, the dated Au-bearing beresite and quartz-carbonate veins are located in the shear zone and replace Mesoarchean (˜2.9 Ga) mafic and felsic metavolcanic rocks of the Koikar-Kobozero greenstone belt. At the Taloveis ore occurrence in the Kostomuksha greenstone belt of western Karelia, the dated beresite replaces Neoarchean (˜2.7 Ga) granitoids and is conjugated with quartz veins in the shear zone. At the Faddeinkelja occurrence of southern Karelia, Aubearing beresite in the large tectonic zone, which transects Archean granite and Paleoproterozoic mafic dikes, has been studied. At the Hatunoja occurrence in the Jalonvaara greenstone belt of southwestern Karelia, the studied quartz veins and related gold mineralization are localized in Archean granitoids. The Rb-Sr isochrons based on whole-rock samples and minerals from ore-bearing and metasomatic wall rocks and veins yielded ˜1.7 Ga for all studied objects. This age is interpreted as the time of development of ore-bearing tectonic zones and ore-forming hydrothermal metasomatic alteration. New isotopic data in combination with the results obtained by our precursors allow us to recognize the Paleoproterozoic stage of gold mineralization in the Karelian Craton. This stage was unrelated to the Archean crust formation in the Karelian Block and is a repercussion of the Paleoproterozoic (2.0-1.7 Ga) crust-forming tectonic cycle, which gave rise to the formation of the Svecofennian and Lapland-Kola foldbelts in the framework of the Karelain Craton. The oreforming capability of Paleoproterozoic tectonics in the Archean complexes of the Karelian Craton was probably not great, and its main role consisted in reworking of the Archean gold mineralization of various

  20. Palaeoarchean Barite Deposits in the Barberton Greenstone Belt: Origin and Links to Early Microbial Life

    Science.gov (United States)

    Mason, P. R.; Peters, A.; Nijman, W.; Reimer, T. O.; Whitehouse, M. J.

    2008-12-01

    Barite deposits are considered important for identifying microbial S cycling in Archean rocks since they can provide information about S isotopes in coexisting sulfate and sulfide minerals. However the degree to which barite and pyrite in metasedimentary rocks are related remains unclear. In this study we have investigated the origin of barite and pyrite in four main horizons seen in both outcrop and fresh drill core material from the Lower Mapepe formation (3.26 to 3.23 Ga), Barberton Greenstone Belt, South Africa. Host rocks include shales, cherts, tuffs and conglomerates that are variably silicified and/or affected by carbonate alteration. The high-energy depositional environment of the host rocks, mineralogical textures, barite chemistry and the occurrence of feldspars from the rarely-found celsian-hyalophane-orthoclase series suggest a seafloor exhalative origin for the barite. In contrast pyrite is closely associated with cherts and dolomitic units where rare earth element and Y data support a marine influence. Pyrite chemistry (Co/Ni= 0.1-1, Se/S <5 x 10- 5) also indicates a low temperature sedimentary origin. Multiple S isotope data (32S, 33S, 34S, determined by SIMS) for pyrite indicates a number of arrays with limited δ34S fractionation at constant Δ33S associated with individual syn-sedimentary microcrystalline pyrite layers. Isolated euhedral pyrites in massive chert and barite rich units show much more scatter and larger degrees of Δ33S variation (-1 to +4 ). Our results are consistent with models invoking microbial mass dependent fractionation of a heterogeneous elemental sulfur source derived from atmospheric photolysis. The sulfate reservoir can also be linked to photolysis but there is no clear relationship between the barite and pyrite S isotope data, suggesting that microbial (or abiotic) sulfate reduction was absent at this time or that the basinal sulfate concentration must have remained significantly lower than the mM level prior to barite

  1. Study of crystallization of a basalt glass

    International Nuclear Information System (INIS)

    Basalt vitreous ceramics posses industrial importance by presenting high mechanical resistance to the abrasion. It was studied the obtention and the crystallization of a glass obtained from a basalt of Campinas, Sao Paulo, Brazil, aiming to develop a material with great abrasive resistance. Fusions were made at 1400 deg Celsius in electrical oven and in alumina crucible, of fine residues of basalt mining. The obtained glass was treated in a crystallization temperature of 880 deg Celsius, determined by DSC, by various time of treatment. The present main crystalline phases, detected by XRD, were the magnesium-ferrite (MgFe2O4) and the diopsid Ca(Mg,Fe,Al)(Si,Al)2O6. Analysing the density by the Archimedes methodology and the DRX it was possible to follow the crystallization kinetic up.

  2. Pressure grouting of fractured basalt flows

    International Nuclear Information System (INIS)

    This report describes a field trial of pressure grouting in basalt and presents the results of subsequent coring and permeability measurements. The trial shows that hydraulic conductivity of fractured basalt bedrock can be significantly reduced by pressure injection of cementitious materials. The effectiveness of the pressure grout procedure was evaluated by measuring the change in the hydraulic conductivity of the bedrock. The extent of grout penetration was determined by analyzing postgrout injection drilling chips for the presence of a tracer in the grout and also by examining cores of the treated basalt. Downhole radar mapping indicated major lava flow patterns and follow water movement during a surface infiltration test. A site called Box Canyon, which is northwest of the Idaho National Engineering Laboratory (INEL), was chosen for the study because its surface outcrop geology is similar to the underlying bedrock fracture system at the INEL's Radioactive Waste Management Complex (RWMC)

  3. CO2 sequestration in basalts: laboratory measurements

    Science.gov (United States)

    Otheim, L. T.; Adam, L.; van Wijk, K.; McLing, T. L.; Podgorney, R. K.

    2010-12-01

    Geologic sequestration of CO2 is proposed as the only promising large-scale method to help reduce CO2 gas emission by its capture at large point sources and subsequent long-term storage in deep geologic formations. Reliable and cost-effective monitoring will be important aspect of ensuring geological sequestration is a safe, effective, and acceptable method for CO2 emissions mitigation. Once CO2 injection starts, seismic methods can be used to monitor the migration of the carbon dioxide plume. To calibrate changes in rock properties from field observations, we propose to first analyze changes in elastic properties on basalt cores. Carbon dioxide sequestration in basalt rocks results in fluid substitution and mixing of CO2 with water and rock mineralizations. Carbon dioxide sequestration in mafic rocks creates reactions such as Mg2SiO 4 + CaMgSi2O 6 + 4CO2 = Mg 3Ca(CO 3) 4 + 3SiO2 whereby primary silicate minerals within the basalt react with carbonic acid laden water to creating secondary carbonate minerals and silicates. Using time-lapse laboratory scale experiments, such as laser generated ultrasonic wave propagation; it is possible to observe small changes in the physical properties of a rock. We will show velocity and modulus measurements on three basalt core samples for different saturation. The ultimate goal of the project is to track seismic changes due to fluid substitution and mineralization. The porosity of our basalts ranges from 8% to 12%, and the P-wave velocity increases by 20% to 40% from dry to water saturated conditions. Petrographic analysis (CT-scans, thin sections, XRF, XRf) will aid in the characterization of the mineral structure in these basalts and its correlation to seismic properties changes resulting from fluid substitution and mineralization.

  4. Hardness of basaltic glass-ceramics

    DEFF Research Database (Denmark)

    Jensen, Martin; Smedskjær, Morten Mattrup; Estrup, Maja; Kristjansson, Maria; Lönnroth, Nadja Teresia; Yue, Yuanzheng

    2009-01-01

    The dependence of the hardness of basaltic glass-ceramics on their degree of crystallisation has been explored by means of differential scanning calorimetry, optical microscopy, x-ray diffraction, and Vickers indentation. Different degrees of crystallisation in the basaltic glasses were achieved by...... varying the temperature of heat treatment. The predominant crystalline phase in the glass was identified as augite. It was found that the hardness of the glass phase decreased slightly with an increase in the degree of crystallisation, while that of the augite phase drastically decreased....

  5. Isotopic signature of Madeira basaltic magmatism

    International Nuclear Information System (INIS)

    Chemical composition of the basalts of Madeira Island is studied. To assess the isotopic sources of magmatism the Pb-Sr, Sm-Nd, U-Th-Pb systems were investigated in a number of basalts. It is shown that the island's rocks are characterized by the mostly deplet sources in relation to Pb-Sr and Sm-Nd systems (87Sr/86Sr - 0.70282-0.70292, 143Nd/144Nd - 0.52303-0.51314). Isotopic composition of lead testifies that the magmatism reservoir is some enriched. It is concluded that the magmatism of Madeira Island is a new example of world ocean island's volcanism

  6. The setting of mineralization in a portion of the Eersteling goldfield, Pietersburg granite-greenstone terrane, South Africa

    International Nuclear Information System (INIS)

    Eersteling goldfield is situated in the Pietersburg granite-greenstone terrane within greenstones of the Archaean Eersteling Formation (Pietersburg Group). In the vicinity of the Eersteling Gold Mine, gold occurs in quartz-carbonate vein systems within coupled shear zones. This mineralization occurs within two settings: in east-west-trending shear zones located at lithological contacts or within discrete units (the Pienaar, Doreen, and Girlie reefs); and in Riedal shear zones between east-west trending zones (the Maltz, Dog, and unnamed reefs). In both cases, gold grades are highest within steeply plunging, structurally controlled pay shoots or boudins. Pay shoots in the Pienaar, Maltz, Dog, and an unnamed reef are characterized by the presence of pyrrhotite, chalcopyrite, and pyrite; arsenopyrite is absent or present in extremely minor amounts. Secondary calcite occurs as large crystals in extension fractures and as a finegrained infilling around clasts. Pay shoots in the Doreen and Girlie reefs are characterized by the presence of arsenopyrite and pyrite while pyrrhotite and chalcopyrite characterize low-grade zones. 28 refs., 8 figs., 4 tabs

  7. Petrographic and mineragraphic investigations of the archaean gold placer at Mount Robert in the Pietersburg greenstone belt, Northern Transvaal

    International Nuclear Information System (INIS)

    The fossil gold placer on Mount Robert near Potgietersrus, northern Transvaal, occurs in the Uitkyk Formation. This formation consists of arenaceous rocks with interlayered conglomerates and shales, and occurs at the top of the Archaean Pietersburg Sequence which forms the Pietersburg greenstone belt. The host rock of the occurrence consists of conglomerates. Its fragments indicate that the provenance area consisted of acid porphyritic lava, chert, banded iron-formation, quartzite, basic lava, vein quartz, and shale. It is suggested that the Uitkyk sediments were transported over short distances and originated from the erosion of a greenstone terrane. The mineralogy of the ore is relatively simply and resembles that of the much younger Witwatersrand banket. Rounded allogenic and, to a lesser extent, idiomorphic to hypidiomorphic authigenic pyrite form the main constituents. Less abundant but genetically interesting ore minerals that have been found so far are leucoxene-rutile, chromite, molybdenite, zircon, carbonaceous matter, and brannerite. The Mount Robert occurrence can be regarded as a primitive forerunner of the Witwatersrand goldfield. Ineffective sedimentary enrichment processes and an environment unfavourable for life-forms that could have acted as biogenic gold and uranium concentrators are regarded as possible reasons for the low gold content and scarcity of uranium-bearing minerals in the investigated Uitkyk conglomerates

  8. Late Archean intermediate-felsic magmatism of the South Vygozersky and Kamennozersky greenstone structures of Central Karelia

    Science.gov (United States)

    Myskova, T. A.; Zhitnikova, I. A.; L'vov, P. A.

    2015-07-01

    The geochemistry and zircon geochronology (U-Pb, SHRIMP-II) of Late Archean intermediate-felsic dikes and plagiogranites of the Shilossky massif of the South Vygozersky and Kamennozersky greenstone belts of Central Karelia were studied. Subvolcanic rocks of the dike complex vary in composition from andesitobasalts to rhyolites, in structural-textural peculiarities, and in the formation age, from 2862 ± 8 to 2785 ± 15 Ma. Compositionally and geochronologically (2853 ± 11 Ma), plagiogranites of the Shilossky massif of the South Vygozersky greenstone belts are close to the most ancient dacite and granodiorite porphyry dikes. Dikes intruded synchronously with intrusion of plagiogranites over a period of at least 70 m.y. Geochronologically, subvolcanic rocks of the dike complex and plagiogranites of the Shilossky massif are similar to granitoids of the TTG assemblages of I- and M-type granites. The Sm-Nd model age of some dikes (2970-2880 Ma) is close to the age of rock crystallization, which is evidence in favor of juvenile origin of magma. Dikes with more ancient model age (3050 Ma) are presumed to contain crustal material. Variations in age and ɛNd (from -2.7 to +2.9) indicate the absence of a unified magmatic source.

  9. Modeling of lunar basalt petrogenesis - Sr isotope evidence from Apollo 14 high-alumina basalts

    International Nuclear Information System (INIS)

    This paper reexamines the Sr isotope data available for the Apollo 14 high-alumina basalts in light of the assimilation and fractional crystallization (AFC) process model proposed by Neal et al. (1987, 1988, 1989). Positive linear correlations of Sr-87/Sr-86 with Rb-87/Rb-86 and the Sr abundance (both leading to KREEP) are used as evidence of such an AFC process in the petrogenesis of Apollo 14 high-alumina basalts. The existing Sr isotope data for Apollo 14 high-alumina basalts suggest that there were three AFC cycles. 33 refs

  10. Evidence for spreading in the lower Kam Group of the Yellowknife greenstone belt: Implications for Archaean basin evolution in the Slave Province

    Science.gov (United States)

    Helmstaedt, H.; Padgham, W. A.

    The Yellowknife greenstone belt is the western margin of an Archean turbidite-filled basin bordered on the east by the Cameron River and Beaulieu River volcanic belts (Henderson, 1981; Lambert, 1982). This model implies that rifting was entirely ensialic and did not proceed beyond the graben stage. Volcanism is assumed to have been restricted to the boundary faults, and the basin was floored by a downfaulted granitic basement. On the other hand, the enormous thickness of submarine volcanic rocks and the presence of a spreading complex at the base of the Kam Group suggest that volcanic rocks were much more widespread than indicated by their present distribution. Rather than resembling volcanic sequences in intracratonic graben structures, the Kam Group and its tectonic setting within the Yellowknife greenstone belt have greater affinities to the Rocas Verdes of southern Chile, Mesozoic ophiolites, that were formed in an arc-related marginal basin setting. The similarities of these ophiolites with some Archean volcanic sequences was previously recognized, and served as basis for their marginal-basin model of greenstone belts. The discovery of a multiple and sheeted dike complex in the Kam Group confirms that features typical of Phanerozoic ophiolites are indeed preserved in some greenstone belts and provides further field evidence in support of such a model.

  11. Chronology of early Archaean granite-greenstone evolution in the Barberton Mountain Land, South Africa, based on precise dating by single zircon evaporation

    Science.gov (United States)

    Kruener, Alfred; Byerly, Gary R.; Lowe, Donald R.

    1991-01-01

    Precise Pb-207/Pb-206 single zircon evaporating ages are reported for low-grade felsic metavolcanic rocks within the Onverwacht and Fig Tree Groups of the Barberton Greenstone Belt (BGB), South Africa, as well as for granitoid plutons bordering the belt. Dacitic tuffs of the Hooggenoeg Formation in the upper part of the Onverwacht Group are shown to yield ages between 3445 + or - 3 and 3416 + or - 5 Ma and to contain older crustal components represented by a 3504 + or - 4 Ma old zircon xenocryst. Fig Tree dacitic tuffs and agglomerates have euhedral zircons between 3259 + or - 3 Ma in age which are interpreted to reflect the time of crystallization. The comagmatic relationships between greenstone felsic volcanic units and the surrounding plutonic suites are keynoted. The data adduced show that the Onverwacht and Fig Tree felsic units have distinctly different ages and thus do not constitute a single, tectonically repeated unit as proposed by others. It is argued that conventional multigrain zircon dating may not accurately identify the time of felsic volcanic activity in ancient greenstones, and that the BGB in the Kaapval craton of southern Africa and greenstones in the Pilbara Block of Western Australia may have been part of a larger crustal unit in early Archaean times.

  12. Increased corrosion resistance of basalt reinforced cement compositions with nanosilica

    Directory of Open Access Journals (Sweden)

    URKHANOVA Larisa Alekseevna

    2014-08-01

    Full Text Available Disperse fiber reinforcement is used to improve deformation and shrinkage characteristics, flexural strength of concrete. Basalt roving and thin staple fiber are often used as mineral fibers. The paper considers the problems of using thin basalt fiber produced by centrifugal-blow method. Evaluation of the corrosion resistance of basalt fiber as part of the cement matrix was performed. Nanodispersed silica produced by electron beam accelerator was used to increase corrosion resistance of basalt fiber.

  13. Hydrogen isotope systematics of submarine basalts

    International Nuclear Information System (INIS)

    The D/H ratios and water contents in fresh submarine basalts from the Mid-Atlantic Ridge, the East Pacific Rise, and Hawaii indicate that the primary D/H ratios of many submarine lavas have been altered by processes including (1) outgassing, (2) addition of seawater at magmatic temperature, and (3) low-temperature hydration of glass. Decreases in deltaD and H2O+ from exteriors to interiors of pillows are explained by outgassing of water whereas inverse relations between deltaD and H2O+ in basalts from the Galapagos Rise and the FAMOUS Area are attributed to outgassing of CH4 and H2. A good correlation between deltaD values and H2O is observed in a suite of submarine tholeiites dredged from the Kilauea East Rift Zone where seawater (added directly to the magma), affected only the isotopic compositions of hydrogen and argon. Analyses of some glassy rims indicate that the outer millimeter of the glass can undergo low-temperature hydration by hydroxyl groups having deltaD values as low as -100. deltaD values vary with H2O contents of subaerial transitional basalts from Molokai, Hawaii, and subaerial alkali basalts from the Society Islands, indicating that the primary deltaD values were similar to those of submarine lavas. The results are discussed. (author)

  14. Pressure grouting of fractured basalt flows

    International Nuclear Information System (INIS)

    This report describes a field trial of pressure grouting in basalt and the results of subsequent coring and permeability measurement activities. The objective was to show that the hydraulic conductivity of fractured basalt bedrock can be significantly reduced by pressure injection of cementitious materials. The effectiveness of the pressure grout procedure was evaluated by measuring the change in the hydraulic conductivity of the bedrock. The extent of grout penetration was established by analyzing postgrout injection drilling chips for the presence of a tracer in the grout and also by examining cores of the treated basalt. Downhole radar mapping was used to establish major lava flow patterns and follow water movement during a surface infiltration test. A site called Box Canyon, which is located northwest of the INEL, was chosen for this study due to the similarity of this surface outcrop geology to that of the underlying bedrock fracture system found at the Radioactive Waste Management Complex. This study showed that hydraulic conductivity of basalt can be reduced through pressure grouting of cementitious material

  15. The biological consequences of flood basalt volcanism

    Science.gov (United States)

    Clapham, M.

    2012-12-01

    Flood basalt eruptions are among the largest environmental perturbations of the Phanerozoic. The rapid release of CO2 from a large igneous province would have triggered a chain of events that can include climate warming, ocean acidification, reduced seawater carbonate saturation, and expanded oceanic anoxia. Those stressors have widely negative impacts on marine organisms, especially on calcified taxa, by affecting their respiratory physiology and reducing energy available for growth and reproduction. Many Phanerozoic extinctions, most notably the end-Permian and end-Triassic mass extinctions, coincided with flood basalt eruptions and shared distinctive patterns of taxonomic and ecological selectivity. In these extinctions, highly active organisms were more likely to survive because they possess physiological adaptations for maintaining internal pH during activity, which also proves useful when buffering pH against ocean acidification. In contrast, species that did not move and had low metabolic rates, such as brachiopods and sponges, suffered considerable losses during these extinctions. Heavily-calcified organisms, especially corals, were particularly vulnerable; as a result, ocean acidification and saturation state changes from flood basalt eruptions often triggered crises in reef ecosystems. This characteristic pattern of selectivity during "physiological" extinctions that closely coincided with flood basalts provides a template for assessing the causes of other extinction events. Because these crises also provide deep time analogues for the ongoing anthropogenic crisis of warming, ocean acidification, and expanded anoxia, the selectivity patterns can also help constrain "winners" and "losers" over upcoming decades.

  16. Site identification presentation: Basalt Waste Isolation Project

    International Nuclear Information System (INIS)

    The final step in the site identification process for the Basalt Waste Isolation Project is described. The candidate sites are identified. The site identification methodology is presented. The general objectives which must be met in selecting the final site are listed. Considerations used in the screening process are also listed. Summary tables of the guidelines used are included

  17. Coatings on Atacama Desert Basalt: A Possible Analog for Coatings on Gusev Plains Basalt

    Science.gov (United States)

    Sutter, B.; Golden, D. C.; Amundson, R.; Chong-Diaz, G.; Ming, D. W.

    2007-01-01

    Surface coatings on Gusev Plains basalt have been observed and may contain hematite and nanophase Fe-oxides along with enrichments in P, S, Cl, and K relative to the underlying rock. The Gusev coatings may be derived from the dissolution of adhering soil and/or parent rock along with the addition of S and Cl from outside sources. Transient water for dissolution could be sourced from melting snow during periods of high obliquity, acid fog, and/or ground water (Haskin et al., 2005). Coatings on basalt in the hyper-arid (less than 2mm y(sup -1)) Atacama Desert may assist in understanding the chemistry, mineralogy and formation mechanisms of the Gusev basalt coatings. The Atacama Desert climate is proposed to be analogous to a paleo-Mars climate that was characterized by limited aqueous activity when the Gusev coatings could have formed. The objectives of this work are to (i) determine the chemical nature and extent of surface coatings on Atacama Desert basalt, and (ii) assess coating formation mechanisms in the Atacama Desert. Preliminary backscattered electron imaging of Atacama basalt thin-sections indicated that the coatings are as thick as 20 m. The boundary between the coating and the basalt labradorite, ilmenite, and augite grains was abrupt indicating that the basalt minerals underwent no chemical dissolution. The Atacama coatings have been added to the basalt instead of being derived from basalt chemical weathering. Semi-quantitative energy dispersive spectroscopy shows the coatings to be chemically homogeneous. The coating is depleted in Ca (0.9 wt% CaO) and enriched in K (1.3 wt.% K2O) and Si (69.1 wt.% SiO2) relative to the augite and labradorite grains. A dust source enriched in Si (e.g., poorly crystalline silica) and K and depleted in Ca appears to have been added to the basalt surface. Unlike the Gusev coatings, no P, S, and Cl enrichment was observed. However, Fe (3.2 wt.% FeO) was present in the Atacama coatings suggesting the present of Fe

  18. Sulfur isotope homogeneity of lunar mare basalts

    Science.gov (United States)

    Wing, Boswell A.; Farquhar, James

    2015-12-01

    We present a new set of high precision measurements of relative 33S/32S, 34S/32S, and 36S/32S values in lunar mare basalts. The measurements are referenced to the Vienna-Canyon Diablo Troilite (V-CDT) scale, on which the international reference material, IAEA-S-1, is characterized by δ33S = -0.061‰, δ34S ≡ -0.3‰ and δ36S = -1.27‰. The present dataset confirms that lunar mare basalts are characterized by a remarkable degree of sulfur isotopic homogeneity, with most new and published SF6-based sulfur isotope measurements consistent with a single mass-dependent mean isotopic composition of δ34S = 0.58 ± 0.05‰, Δ33S = 0.008 ± 0.006‰, and Δ36S = 0.2 ± 0.2‰, relative to V-CDT, where the uncertainties are quoted as 99% confidence intervals on the mean. This homogeneity allows identification of a single sample (12022, 281) with an apparent 33S enrichment, possibly reflecting cosmic-ray-induced spallation reactions. It also reveals that some mare basalts have slightly lower δ34S values than the population mean, which is consistent with sulfur loss from a reduced basaltic melt prior to eruption at the lunar surface. Both the sulfur isotope homogeneity of the lunar mare basalts and the predicted sensitivity of sulfur isotopes to vaporization-driven fractionation suggest that less than ≈1-10% of lunar sulfur was lost after a potential moon-forming impact event.

  19. Geochemistry and petrogenesis of intrusions at the Golden Pride gold deposit in the Nzega greenstone belt, Tanzania

    Science.gov (United States)

    Kwelwa, Shimba; Manya, Shukrani; Vos, Ivo M. A.

    2013-10-01

    The greenstone sequence at Golden Pride gold deposit in Nzega greenstone belt of northern Tanzania is cross-cut by several intrusions whose geochemistry and petrogenesis is unknown. We present major and trace elements geochemistry of the Golden Pride igneous intrusions with the aim of constraining their petrogenesis and their ancient tectonic setting. The Golden Pride intrusions are geochemically categorized into two main rock suites: the granodiorites (which include the porphyries) and the lamprophyres (formerly intermediate intrusions). The granodiorites are characterized by SiO2 contents of 54.5-69.9 wt%, elevated MgO (1.22-3.59 wt%) Cr (up to 54 ppm), Mg# (35-55) pointing to a mantle component in the source. Compared to the TTG and adakites, the granodiorites are characterized by higher K2O (1.52-4.30 wt%), medium HREE (Gd/ErCN = 2.13-3.77) and marked enrichment in Ba and Sr (Ba + Sr = 819-2922 ppm) and are in these respects similar to Archean high Ba-Sr sanukitoids. The rocks in this suite are interpreted to have formed by partial melting of an enriched mantle wedge through two metasomatic events: subduction-related fluids/melts and by metasomatism related to asthenospheric mantle upwelling caused by slab break-off. Compared to the granodiorites, the lamprophyres have higher MgO contents (2.37-3.81 wt%), Cr (60-298 ppm), Co (31-57 ppm) and Mg# (32-40). They also show slight enrichment of the LREE relative to HREE (La/YbCN = 3.3-7.1), moderate Nb-Ti depletion and sub-chondritic Zr/Hf ratios (34-41). These geochemical features are attributed to derivation of the Golden Pride lamprophyres by partial melting of the amphibole-rich metasomatized mantle by slab derived hydrous fluids. Both of the Golden Pride intrusion suites show strong affinity to subduction related magmas and we interpret that the entire greenstone sequence and the associated intrusions at Golden Pride gold deposit formed in a late Archaean convergent margin.

  20. Basalt Waste Isolation Program: monthly report

    Energy Technology Data Exchange (ETDEWEB)

    Deju, R A

    1978-01-31

    40 square miles were geologically mapped in the vicinity of Hanford. In the hydrologic program, testing procedures were established and preparation initiated to develop the tools needed for field testing. The waste/basalt interaction studies continued. The hydrothermal treatment experiments involving simulated waste-glass spheroids were conducted to determine the extent of alteration products. Large-volume reconnaissance experiments utilizing spent unreprocessed fuel, Hanford water, and actual basalt samples were initiated. Hydrologic Hole DC-5 was completed just below 3,500 feet. Cable tool operations at DC-8 were progressing normally, with a depth at the end of the reporting period of 428 feet. Core Hole DC-11 at Gable Mountain was completed Jan. 10 at a total depth of 385 feet. Core Hole DC-6 now has casing cemented to 1,100 feet and is being cored at 1,200 feet.

  1. Northwest Africa 5298: A Basaltic Shergottite

    Science.gov (United States)

    Hui, Hejiu; Peslier, Anne; Lapen, Thomas J.; Brandon, Alan; Shafer, John

    2009-01-01

    NWA 5298 is a single 445 g meteorite found near Bir Gandouz, Morocco in March 2008 [1]. This rock has a brown exterior weathered surface instead of a fusion crust and the interior is composed of green mineral grains with interstitial dark patches containing small vesicles and shock melts [1]. This meteorite is classified as a basaltic shergottite [2]. A petrologic study of this Martian meteorite is being carried out with electron microprobe analysis and soon trace element analyses by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Oxygen fugacity is calculated from Fe-Ti oxides pairs in the sample. The data from this study constrains the petrogenesis of basaltic shergottites.

  2. Technical program plan, Basalt Waste Isolation Project

    International Nuclear Information System (INIS)

    The Basalt Waste Isolation Project (BWIP) program as administered by the DOE's Richland Operations Office and Rockwell Hanford Operations is described. The objectives, scope and scientific technologies are discussed. The work breakdown structure of the project includes: project management and support, systems integration, geosciences, hydrology, engineered barriers, test facility design and construction, engineering testing, repository studies, and schedules. The budget of the program including operating and capital cost control is also included

  3. Basalt FRP Spike Repairing of Wood Beams

    OpenAIRE

    Luca Righetti; Marco Corradi; Antonio Borri

    2015-01-01

    This article describes aspects within an experimental program aimed at improving the structural performance of cracked solid fir-wood beams repaired with Basalt Fiber Reinforced Polymer (BFRP) spikes. Fir wood is characterized by its low density, low compression strength, and high level of defects, and it is likely to distort when dried and tends to fail under tension due to the presence of cracks, knots, or grain deviation. The proposed repair technique consists of the insertion of BFRP spik...

  4. Technical program plan, Basalt Waste Isolation Project

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-12-01

    The Basalt Waste Isolation Project (BWIP) program as administered by the DOE's Richland Operations Office and Rockwell Hanford Operations is described. The objectives, scope and scientific technologies are discussed. The work breakdown structure of the project includes: project management and support, systems integration, geosciences, hydrology, engineered barriers, test facility design and construction, engineering testing, repository studies, and schedules. The budget of the program including operating and capital cost control is also included. (DC)

  5. Structural relaxation in annealed hyperquenched basaltic glasses

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, John C.; Potuzak, M.;

    2012-01-01

    The enthalpy relaxation behavior of hyperquenched (HQ) and annealed hyperquenched (AHQ) basaltic glass is investigated through calorimetric measurements. The results reveal a common onset temperature of the glass transition for all the HQ and AHQ glasses under study, indicating that the primary...... relaxation is activated at the same temperature regardless of the initial departure from equilibrium. The analysis of secondary relaxation at different annealing temperatures provides insights into the enthalpy recovery of HQ glasses....

  6. Nanoparticulate mineral matter from basalt dust wastes.

    Science.gov (United States)

    Dalmora, Adilson C; Ramos, Claudete G; Querol, Xavier; Kautzmann, Rubens M; Oliveira, Marcos L S; Taffarel, Silvio R; Moreno, Teresa; Silva, Luis F O

    2016-02-01

    Ultra-fine and nano-particles derived from basalt dust wastes (BDW) during "stonemeal" soil fertilizer application have been the subject of some concern recently around the world for their possible adverse effects on human health and environmental pollution. Samples of BDW utilized were obtained from companies in the mining district of Nova Prata in southern Brazil for chemical characterization and nano-mineralogy investigation, using an integrated application of advanced characterization techniques such as X-ray diffraction (XRD), High Resolution-Transmission Electron microscopy (HR-TEM)/(Energy Dispersive Spectroscopy) EDS/(selected-area diffraction pattern) SAED, Field Emission-Scanning Electron Microscopy (FE-SEM)/EDS and granulometric distribution analysis. The investigation has revealed that BDW materials are dominated by SiO2, Al2O3 and Fe2O3, with a complex micromineralogy including alkali feldspar, augite, barite, labradorite, hematite, heulandrite, gypsum, kaolinite, quartz, and smectite. In addition we have identified a number of trace metals such as Cd, Cu, Cr, Zn that are preferentially concentrated into the finer, inhalable, dust fraction and could so present a health hazard in the urban areas around the basalt mining zone. The implication of this observation is that use of these nanometric-sized particulates as soil fertilizer may present different health challenges to those of conventional fertilizers, inviting future work regarding the relative toxicities of these materials. Our investigation on the particle size distribution, nano-particle mineralogy and chemical composition in typical BDW samples highlights the need to develop cleaning procedures to minimise exposure to these natural fertilizing basalt dust wastes and is thus of direct relevance to both the industrial sector of basalt mining and to agriculture in the region. PMID:26551199

  7. Extensional tectonics during the igneous emplacement of the mafic-ultramafic rocks of the Barberton greenstone belt

    Science.gov (United States)

    Dewit, M. J.

    1986-01-01

    The simatic rocks (Onverwacht Group) of the Barberton greenstone belt are part of the Jamestown ophiolite complex. This ophiolite, together with its thick sedimentary cover occupies a complex thrust belt. Field studies have identified two types of early faults which are entirely confined to the simatic rocks and are deformed by the later thrusts and associated folds. The first type of fault (F1a) is regional and always occurs in the simatic rocks along and parallel to the lower contacts of the ophiolite-related cherts (Middle Marker and equivalent layers). These fault zones have previously been referred to both as flaser-banded gneisses and as weathering horizons. In general the zones range between 1-30m in thickness. Displacements along these zones are difficult to estimate, but may be in the order of 1-100 km. The structures indicate that the faults formed close to horizontal, during extensional shear and were therefore low angle normal faults. F1a zones overlap in age with the formation of the ophiolite complex. The second type of faults (F1b) are vertical brittle-ductile shear zones, which crosscut the complex at variable angles and cannot always be traced from plutonic to overlying extrusive (pillowed) simatic rocks. F1b zones are also apparently of penecontemporaneous origin with the intrusive-extrusive igneous processs. F1b zones may either represent transform fault-type activity or represent root zones (steepened extensions) of F1a zones. Both fault types indicate extensive deformation in the rocks of the greenstone belt prior to compressional overthrust tectonics.

  8. Increased corrosion resistance of basalt reinforced cement compositions with nanosilica

    OpenAIRE

    URKHANOVA Larisa Alekseevna; LKHASARANOV Solbon Aleksandrovich; ROZINA Victoria Yevgenievna; BUYANTUEV Sergey Lubsanovich; BARDAKHANOV Sergey Prokopievich

    2014-01-01

    Disperse fiber reinforcement is used to improve deformation and shrinkage characteristics, flexural strength of concrete. Basalt roving and thin staple fiber are often used as mineral fibers. The paper considers the problems of using thin basalt fiber produced by centrifugal-blow method. Evaluation of the corrosion resistance of basalt fiber as part of the cement matrix was performed. Nanodispersed silica produced by electron beam accelerator was used to increase corrosion resistance of ba...

  9. FOAM CONCRETE REINFORCEMENT BY BASALT FIBRES

    Directory of Open Access Journals (Sweden)

    Zhukov Aleksey Dmitrievich

    2012-10-01

    Full Text Available The authors demonstrate that the foam concrete performance can be improved by dispersed reinforcement, including methods that involve basalt fibres. They address the results of the foam concrete modeling technology and assess the importance of technology-related parameters. Reinforcement efficiency criteria are also provided in the article. Dispersed reinforcement improves the plasticity of the concrete mix and reduces the settlement crack formation rate. Conventional reinforcement that involves metal laths and rods demonstrates its limited application in the production of concrete used for thermal insulation and structural purposes. Dispersed reinforcement is preferable. This technology contemplates the infusion of fibres into porous mixes. Metal, polymeric, basalt and glass fibres are used as reinforcing components. It has been identified that products reinforced by polypropylene fibres demonstrate substantial abradability and deformability rates even under the influence of minor tensile stresses due to the low adhesion strength of polypropylene in the cement matrix. The objective of the research was to develop the type of polypropylene of D500 grade that would demonstrate the operating properties similar to those of Hebel and Ytong polypropylenes. Dispersed reinforcement was performed by the basalt fibre. This project contemplates an autoclave-free technology to optimize the consumption of electricity. Dispersed reinforcement is aimed at the reduction of the block settlement in the course of hardening at early stages of their operation, the improvement of their strength and other operating properties. Reduction in the humidity rate of the mix is based on the plasticizing properties of fibres, as well as the application of the dry mineralization method. Selection of optimal parameters of the process-related technology was performed with the help of G-BAT-2011 Software, developed at Moscow State University of Civil Engineering. The authors also

  10. Study on basalt fiber parameters affecting fiber-reinforced mortar

    Science.gov (United States)

    Orlov, A. A.; Chernykh, T. N.; Sashina, A. V.; Bogusevich, D. V.

    2015-01-01

    This article considers the effect of different dosages and diameters of basalt fibers on tensile strength increase during bending of fiberboard-reinforced mortar samples. The optimal dosages of fiber, providing maximum strength in bending are revealed. The durability of basalt fiber in an environment of cement, by means of microscopic analysis of samples of fibers and fiberboard-reinforced mortar long-term tests is examined. The article also compares the behavior of basalt fiber in the cement stone environment to a glass one and reveals that the basalt fiber is not subject to destruction.

  11. Some magnetic and XP S measurements of basalt rocks

    International Nuclear Information System (INIS)

    We have studied some magnetic properties of the basalt rocks using a SQUID magnetometer. Hysteresis loops at different temperatures have been measured. The Magnetic show that ferromagnetic (and possibly ferrimagnetic) ordering is present in basalt rocks. Curie temperature for the studied samples were determined to be about 330 K. The low Curie temperature is probably due to the contribution of paramagnetic ions present in the sample. X-ray photoelectron spectroscopy (XP S) was used to determine the elements present in the basaltic sample. Major elements present in the basalt ro ks such as Si Al, Ca, fe, and Mg were detected. (author).12 refs., 6 figs.,

  12. Quantifying glassy and crystalline basalt partitioning in the oceanic crust

    Science.gov (United States)

    Moore, Rachael; Ménez, Bénédicte

    2016-04-01

    The upper layers of the oceanic crust are predominately basaltic rock, some of which hosts microbial life. Current studies of microbial life within the ocean crust mainly focus on the sedimentary rock fraction, or those organisms found within glassy basalts while the potential habitability of crystalline basalts are poorly explored. Recently, there has been recognition that microbial life develops within fractures and grain boundaries of crystalline basalts, therefore estimations of total biomass within the oceanic crust may be largely under evaluated. A deeper understanding of the bulk composition and fractionation of rocks within the oceanic crust is required before more accurate estimations of biomass can be made. To augment our understanding of glassy and crystalline basalts within the oceanic crust we created two end-member models describing basalt fractionation: a pillow basalt with massive, or sheet, flows crust and a pillow basalt with sheeted dike crust. Using known measurements of massive flow thickness, dike thickness, chilled margin thickness, pillow lava size, and pillow lava glass thickness, we have calculated the percentage of glassy versus crystalline basalts within the oceanic crust for each model. These models aid our understanding of textural fractionation within the oceanic crust, and can be applied with bioenergetics models to better constrain deep biomass estimates.

  13. Mechanical and morphological properties of basalt filled polymer matrix composites

    Directory of Open Access Journals (Sweden)

    A. Akinci

    2009-01-01

    Full Text Available Purpose: The aim of this work is to study the effect of basalt on physical, mechanical and morphological of the injection molded LDPE.Design/methodology/approach: In this study, the effect of basalt was investigated as a filler material in polymer matrix composite (PMC and low density polyethylene (LDPE was chosen as a matrix material.Findings: A variety of mechanical tests were performed on the resultant composites which has appropriate compositions. Tensile, flexural, density and hardness tests have been carried out and, the relationship between the basalt content and properties were examined. XRD and SEM facilities were applied on polished and fractured surfaces after flexural tests respectively.Research limitations/implications: In present study, it was found that, the content of basalt filler affected structural integrity and mechanical properties of composites. With increasing the amount of the basalt addition to the LDPE results in a decrease in elongation at break values.Originality/value: It is thought that the nucleating effect of the basalt leads to an increased rate in orientation of the polymer. The crystallization was increased by increasing the basalt content. Basalt addition was observed to be an alternative additive to the LDPE. If suitable coupling agents could be added to basalt and LDPE mixtures, the mechanical properties can possibly be increased.

  14. Microbial colonization and alteration of basaltic glass

    Directory of Open Access Journals (Sweden)

    J. Einen

    2006-03-01

    Full Text Available Microorganisms have been reported to be associated with the alteration of the glassy margin of seafloor pillow basalts (Thorseth et al., 2001, 2003; Lysnes et al., 2004. The amount of iron and other biological important elements present in basalts and the vast abundance of basaltic glass in the earth's crust, make glass alteration an important process in global element cycling. To gain further insight into microbial communities associated with glass alteration, five microcosm experiments mimicking seafloor conditions were inoculated with seafloor basalt and incubated for one year. Mineral precipitations, microbial attachment to the glass and glass alteration were visualized by scanning electron microscopy (SEM, and the bacterial community composition was fingerprinted by PCR and denaturing gradient gel electrophoresis (DGGE in combination with sequencing. SEM analysis revealed a microbial community with low morphological diversity of mainly biofilm associated and prosthecate microorganisms. Approximately 30 nm thick alteration rims developed on the glass in all microcosms after one year of incubation; this however was also seen in non inoculated controls. Calcium carbonate precipitates showed parallel, columnar and filamentous crystallization habits in the microcosms as well as in the sterile controls. DGGE analysis showed an alteration in bacterial community profiles in the five different microcosms, as a response to the different energy and redox regimes and time. In all microcosms a reduction in number of DGGE bands, in combination with an increase in cell abundance were recorded during the experiment. Sequence analysis showed that the microcosms were dominated by four groups of organisms with phylogenetic affiliation to four taxa: The Rhodospirillaceae, a family containing phototrophic marine organisms, in which some members are capable of heterotrophic growth in darkness and N2 fixation; the family Hyphomicrobiaceae, a group

  15. Microbial colonization and alteration of basaltic glass

    Science.gov (United States)

    Einen, J.; Kruber, C.; Øvreås, L.; Thorseth, I. H.; Torsvik, T.

    2006-03-01

    Microorganisms have been reported to be associated with the alteration of the glassy margin of seafloor pillow basalts (Thorseth et al., 2001, 2003; Lysnes et al., 2004). The amount of iron and other biological important elements present in basalts and the vast abundance of basaltic glass in the earth's crust, make glass alteration an important process in global element cycling. To gain further insight into microbial communities associated with glass alteration, five microcosm experiments mimicking seafloor conditions were inoculated with seafloor basalt and incubated for one year. Mineral precipitations, microbial attachment to the glass and glass alteration were visualized by scanning electron microscopy (SEM), and the bacterial community composition was fingerprinted by PCR and denaturing gradient gel electrophoresis (DGGE) in combination with sequencing. SEM analysis revealed a microbial community with low morphological diversity of mainly biofilm associated and prosthecate microorganisms. Approximately 30 nm thick alteration rims developed on the glass in all microcosms after one year of incubation; this however was also seen in non inoculated controls. Calcium carbonate precipitates showed parallel, columnar and filamentous crystallization habits in the microcosms as well as in the sterile controls. DGGE analysis showed an alteration in bacterial community profiles in the five different microcosms, as a response to the different energy and redox regimes and time. In all microcosms a reduction in number of DGGE bands, in combination with an increase in cell abundance were recorded during the experiment. Sequence analysis showed that the microcosms were dominated by four groups of organisms with phylogenetic affiliation to four taxa: The Rhodospirillaceae, a family containing phototrophic marine organisms, in which some members are capable of heterotrophic growth in darkness and N2 fixation; the family Hyphomicrobiaceae, a group of prosthecate oligotrophic

  16. East Mariana Basin tholeiites: Cretaceous intraplate basalts or rift basalts related to the Ontong Java plume?

    Science.gov (United States)

    Castillo, P.R.; Pringle, M.S.; Carlson, R.W.

    1994-01-01

    Studies of seafloor magnetic anomaly patterns suggest the presence of Jurassic oceanic crust in a large area in the western Pacific that includes the East Mariana, Nauru and Pigafetta Basins. Sampling of the igneous crust in this area by the Deep Sea Drilling Program (DSDP) and the Ocean Drilling Program (ODP) allows direct evaluation of the age and petrogenesis of this crust. ODP Leg 129 drilled a 51 m sequence of basalt pillows and massive flows in the central East Mariana Basin. 40Ar 39Ar ages determined in this study for two Leg 129 basalts average 114.6 ?? 3.2 Ma. This age is in agreement with the Albian-late Aptian paleontologic age of the overlying sediments, but is distinctively younger than the Jurassic age predicted by magnetic anomaly patterns in the basin. Compositionally, the East Mariana Basin basalts are uniformly low-K tholeiites that are depleted in highly incompatible elements compared to moderately incompatible ones, which is typical of mid-ocean ridge basalts (MORB) erupted near hotspots. The Sr, Nd and Pb isotopic compositions of the tholeiites ( 87Sr 86Srinit = 0.70360-0.70374; 143Nd 144Ndinit = 0.512769-0.512790; 206Pb 204Pbmeas = 18.355-18.386) also overlap with some Indian Ocean Ridge MORB, although they are distinct from the isotopic compositions of Jurassic basalts drilled in the Pigafetta Basin, the oldest Pacific MORB. The isotopic compositions of the East Mariana Basin tholeiites are also similar to those of intraplate basalts, and in particular, to the isotopic signature of basalts from the nearby Ontong Java and Manihiki Plateaus. The East Mariana Basin tholeiites also share many petrologic and isotopic characteristics with the oceanic basement drilled in the Nauru Basin at DSDP Site 462. In addition, the new 110.8 ?? 1.0 Ma 40Ar 39Ar age for two flows from the bottom of Site 462 in the Nauru Basin is indistinguishable from the age of the East Mariana Basin flows. Thus, while magnetic anomaly patterns predict that the igneous

  17. Crystal Stratigraphy of Two Basalts from Apollo 16: Unique Crystallization of Picritic Basalt 606063,10-16 and Very-Low-Titanium Basalt 65703,9-13

    Science.gov (United States)

    Donohue, P. H.; Neal, C. R.; Stevens, R. E.; Zeigler, R. A.

    2014-01-01

    A geochemical survey of Apollo 16 regolith fragments found five basaltic samples from among hundreds of 2-4 mm regolith fragments of the Apollo 16 site. These included a high-Ti vitrophyric basalt (60603,10-16) and one very-low-titanium (VLT) crystalline basalt (65703,9-13). Apollo 16 was the only highlands sample return mission distant from the maria (approx. 200 km). Identification of basaltic samples at the site not from the ancient regolith breccia indicates input of material via lateral transport by post-basin impacts. The presence of basaltic rocklets and glass at the site is not unprecedented and is required to satisfy mass-balance constraints of regolith compositions. However, preliminary characterization of olivine and plagioclase crystal size distributions indicated the sample textures were distinct from other known mare basalts, and instead had affinities to impact melt textures. Impact melt textures can appear qualitatively similar to pristine basalts, and quantitative analysis is required to distinguish between the two in thin section. The crystal stratigraphy method is a powerful tool in studying of igneous systems, utilizing geochemical analyses across minerals and textural analyses of phases. In particular, trace element signatures can aid in determining the ultimate origin of these samples and variations document subtle changes occurring during their petrogenesis.

  18. Petrogenesis of Apollo 12 mare basalts. Part 1: Multiple melts and fractional crystallization to explain olivine and ilmenite basalt compositions

    Science.gov (United States)

    Neal, Clive R.; Taylor, Lawrence A.

    1993-01-01

    Mare basalts returned by the Apollo 12 mission have been divided into 4 groups on the basis of mineralogy and whole-rock chemistry: olivine basalts; pigeonite basalts; ilmenite basalts; and feldspathic basalts. James and Wright and Rhodes et al. concluded that the olivine and pigeonite groups were co-magmatic and that the within group variations are due to fractional crystallization of olivine and minor Cr-spinel, with pigeonite replacing olivine in the pigeonite basalts. Rhodes et al. concluded that the parental compositions for these suites were probably represented by the vitrophyres, and the olivine basalts are comprised essentially of cumulates and the pigeonites of evolved end-members. However, Neal et al. have demonstrated, using trace-element considerations, that the Apollo 12 olivine and pigeonite suites are not related. The ilmenite basalts were studied extensively by Dungan and Brown who noted that both cumulates and evolved fractionates were present within this group. In their modeling, Dungan and Brown used the vitrophyre compositions as parents. Neal et al. demonstrated that the feldspathic suite was probably comprised of only one member - 12038. Herein, the ilmenite and olivine basalts are demonstrated to be the products of several non-modal partial melting events of a single source followed by closed-system fractional crystallization.

  19. Is Ishtar Terra a thickened basaltic crust?

    Science.gov (United States)

    Arkani-Hamed, Jafar

    1992-01-01

    The mountain belts of Ishtar Terra and the surrounding tesserae are interpreted as compressional regions. The gravity and surface topography of western Ishtar Terra suggest a thick crust of 60-110 km that results from crustal thickening through tectonic processes. Underthrusting was proposed for the regions along Danu Montes and Itzpapalotl Tessera. Crustal thickening was suggested for the entire Ishtar Terra. In this study, three lithospheric models with total thicknesses of 40.75 and 120 km and initial crustal thicknesses of 3.9 and 18 km are examined. These models could be produced by partial melting and chemical differentiation in the upper mantle of a colder, an Earth-like, and a hotter Venus having temperatures of respectively 1300 C, 1400 C, and 1500 C at the base of their thermal boundary layers associated with mantle convection. The effects of basalt-granulite-eclogite transformation (BGET) on the surface topography of a thickening basaltic crust is investigated adopting the experimental phase diagram and density variations through the phase transformation.

  20. Kinetics of anorthite dissolution in basaltic melt

    Science.gov (United States)

    Yu, Yi; Zhang, Youxue; Chen, Yang; Xu, Zhengjiu

    2016-04-01

    We report convection-free anorthite dissolution experiments in a basaltic melt at 1280-1500 °C and 0.5 GPa on two different crystallographic surfaces, (1 2 1 bar) and (3 bar 0 2) to investigate dissolution kinetics. The anisotropy of the anorthite dissolution rate along these two surfaces is negligible. Time series experiments at ∼1280 °C show that anorthite dissolution is mainly controlled by diffusion in the melt within experimental uncertainty. Analytical solutions were used to model the dissolution and diffusion processes, and to obtain the diffusivities and the saturation concentrations of the equilibrium-determining component (Al2O3) for anorthite dissolution into the basaltic melt. For the first time, we are able to show the physical and chemical characteristics of quench growth effect on the near-interface melt using high spatial resolution (0.3 μm) EDS analyses. For anorthite (An# ⩾ 90) saturation in a melt with 39-53 wt% SiO2 and ⩽0.4 wt% H2O, the concentration of Al2O3 in wt% depends on temperature as follows:

  1. Qingyuan high-grade granite-greenstone terrain in the Eastern North China Craton: Root of a Neoarchaean arc

    Science.gov (United States)

    Peng, Peng; Wang, Chong; Wang, Xinping; Yang, Shuyan

    2015-11-01

    The Qingyuan high-grade granite-greenstone terrain is one of the first recognized granite-greenstone terrains in the Eastern North China Craton. Similar to other Archaean terrains, its tectonic environment is debated: was it an intra-continental rift or a modern analogy of arc? Occurrence and petrogenesis of major igneous series, the ultramafic-mafic and felsic volcanic rocks (> 2510 Ma) and the plutons of the quartz diorite (2570-2510 Ma), TTG (2570-2510 Ma) and quartz monzodiorite (2510-2490 Ma) series in Xinbin area are investigated. The mafic intrusives and volcanic rocks have high MgO content (5.4-7.5 wt.%) and Mg-number (48-61). They show slightly depleted to flat trace element patterns. The ultramafic rocks (serpentinite) could be genetically related to the mafic rocks. The meta-dacite-rhyolite is adakitic with enriched light and middle REEs and LILEs, but significantly depleted HFSEs. The quartz diorite has high Mg-number (60-64), moderately enriched light and middle REEs and LILEs. The TTG shows distinct light but moderate middle REE-enrichment, prominent Nb-Ta-depletion but Zr-Hf-enrichment (Zr/Sm > 100). The quartz monzodiorite has moderate light and middle REE-enrichment, significant Nb-Ta-depletion, and negative Eu-/Sr-anomalies. The TTG has more depleted Sr-Nd isotopes (εNdt = + 2-+ 6; 87Sr/86Srt = ~ 0.700) than all the others (εNdt = 0-+ 2; 87Sr/86Srt = 0.701-703). Their petrogenesis can be explained by an Archaean-style subduction defined as a mantle wedge-absent flat-'hot'-subduction with significant vertical tectonism in the overriding slab: the ultramafic-mafic rocks were originated from primitive mantle; the meta-dacite-rhyolite was originated from the eclogite facies overriding crust; the quartz diorite was a mixture of melts from mantle and the overriding crust; the TTG was from the subducting slab under amphibolite to amphibole-bearing eclogite facies; and the quartz monzodiorite was from the subducting slab after the derivation of the TTG

  2. The rheological behavior of fracture-filling cherts: example from Barite Valley dikes, Barberton greenstone Belt, South Africa.

    Science.gov (United States)

    Ledevin, Morgane; Arndt, Nicholas; Simionovici, Alexandre

    2014-05-01

    A 100m-thick complex of black carbonaceous chert dikes marks the transition from the Mendon to Mapepe Formations (3260 Ma) in the Barberton Greenstone Belt, South Africa. Fracturing was intense in this area, as shown by the profusion and width of the chert dikes (ca. 1m on average) and by the abundance of completely shattered rocks. Similar structures occur in many greenstones worldwide. Here we investigate (1) the origin of the dikes and (2) the nature of the material that precipitated to form the fracture-filling chert. The dike-and-sill organization of the plumbing system and the upward narrowing of some of the large veins indicate that at least part of the fluid originated at depth and migrated upward. Abundant angular fragments of silicified country rock are suspended and uniformly distributed within the larger dikes. Jigsaw-fit structures and confined bursting textures indicate that hydraulic fracturing was at the origin of the fractures, a particularity attributed to the confinement of the hydrothermal system below an impermeable cape of chert. The location of the dikes beneath an impact spherule bed leads us to propose that the hydrothermal circulation was related to the impact. The present site may have been located at the external margin of a large crater. The geometry of the dikes and the petrography of the cherts indicate that the fluid that invaded the fractures was thixotropic. The injection of black chert into extremely fine fractures is evidence oflow viscosity at the time of injection while the lack of closure of larger veins below eroded country blocks and the suspension of fragments in a chert matrix provides evidence of high viscosity soon thereafter. The inference is that the viscosity of the injected fluid increased from low to high as the fluid velocity decreased. Such rheological behavior is characteristic of media composed of solid and colloidal particles suspended in a fluid. The presence of abundant clay-sized particles of silica

  3. Vesicularity of basalt erupted at Reykjanes Ridge crest

    Science.gov (United States)

    Duffield, W.A.

    1978-01-01

    Average vesicularity of basalt drilled at three sites on the west flank of the Reykjanes Ridge increases with decreasing age. This change apparently records concomitant decrease in water depth at the ridge crest where the basalt was erupted and suggests substantial upward growth of the crest during the past 35 Myr. ?? 1978 Nature Publishing Group.

  4. Hydrothermal interaction of a ceramic waste form with basalt

    International Nuclear Information System (INIS)

    The behavior of crystalline supercalcine-ceramic in the presence of basalt was investigated under mild hydrothermal conditions at 100, 200, and 3000C with a pressure of 300 bars. Both the solid phases and solution concentrations of the interaction products of basalt and supercalcine-ceramic were characterized. At 1000C, no alteration products could be detected in experiments involving supercalcine-ceramic and basalt. The solution analyses for elements specific to the supercalcine-ceramic did not indicate any significant differences between the treatments with and without basalt, suggesting little or no interaction between basalt and supercalcine-ceramic at this temperature. At 3000C, several solid alteration/interaction products were identified. These products included two phases, pollucite and scheelite, originally incorporated into the ceramic formulation but which reformed with different bulk chemical compositions. In addition, isolated crystals of unidentified K (+-Ba) aluminosilicate phases were observed. Solution analyses of these runs did not indicate any significant differences between the treatments of supercalcine-ceramic with and without basalt, except that the Sr concentration decreased in the presence of basalt. Similar behavior was noted earlier, when basalt and SrZrO3 experiments were conducted. Alteration products and solution concentrations at 2000C lie intermediate between the 1000 and 3000C results

  5. Hydrogeology of the basalts in the Uruguayan NW

    International Nuclear Information System (INIS)

    This work is about the hydrogeological aspects in the NW Uruguayan basaltic area. The results of this research are the main geological, morphological and hydrogeological aspects of the area as well as the characteristics and the color of the basalt and sandstones

  6. A note on incipient spilitisation of central Indian basin basalts

    Digital Repository Service at National Institute of Oceanography (India)

    Karisiddaiah, S.M.; Iyer, S.D.

    of chlorite, epidote and opaques. The oxide variation plots indicate a mid-ocean ridge basalt trend for the samples, which have been spilitised to varying degrees. It is suggested that the basalts formed as a result of a fissure type of eruption along...

  7. Origin of High-Alumina Basalt, Andesite, and Dacite Magmas.

    Science.gov (United States)

    Hamilton, W

    1964-10-30

    The typical volcanic rocks of most island arcs and eugeosynclines, and of some continental environments, are basalt, andesite, and dacite, of high alumina content. The high-alumina basalt differs from tholeiitic basalt primarily in having a greater content of the components of calcic plagioclase. Laboratory data indicate that in the upper mantle, below the level at which the basaltic component of mantle rock is transformed by pressure to eclogite or pyroxenite, the entire basaltic portion probably is melted within a narrow temperature range, but that above the level of that transformation plagioclase is melted selectively before pyroxene over a wide temperature range. The broad spectrum of high-alumina magmas may represent widely varying degrees of partial melting above the transformation level, whereas narrow-spectrum tholeiite magma may represent more complete melting beneath it. PMID:17794034

  8. Control of oxidation potential for basalt repository simulation tests

    International Nuclear Information System (INIS)

    Borosilicate waste glass durability in simulated repository environments can be assessed by use of static tests in leach vessels fabricated of the representative geomedia. Control of the oxidation potential during the test simulates a basalt repository environment. Under very anoxic conditions (i.e. at negative Eh values), the interactions between basalt and SRP waste glass in silica-saturated basaltic groundwaters are the same as those of basalt and groundwater when no waste glass is present. The lack of significant leaching of ions from the waste glass and the lack of any significant changes in either the leached surfaces of glass or basalt under anoxic conditions suggests that the components of this system are at equilibrium when oxygen is absent. 11 refs., 4 figs

  9. The discovery of the Neoarchean mafic dyke swarm in Hengshan and reinterpretation of the previous "Wutai greenstone belt"

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The structural mapping and section study indicate that the "greenstone belts" in the southern to central parts of Hengshan were intensively sheared and transposed mafic dyke swarm,which originally intruded into the Neoarchean grey gneiss and high-pressure granulite terrain(HPGT).The HPGT is characterized by flat-dipping structures,to the south it became steep and was cut by the Dianmen mafic dyke swarm.After high-pressure granulite-facies metamorphic event,the mafic dyke swarm occurred,and was associated with the extensional setting and reworked by the late strike-slip shearing.The zircon age dating proves that the Dianmen mafic dyke swarm was emplaced during the period between 2499±4 Ma and 2512±3 Ma,followed by late tectonothermal reworking.The Dianmen mafic dyke swarm further documents the extensional episode in the central to northern parts of North China Craton(NCC),providing the important constraint for the limit between Archean and Proterozoic and correlation between NCC and other cratonic blocks of the world.

  10. 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.)

  11. Heavy minerals in basalt maares and diatremes of South-Slovak alkali basaltic volcanic field

    International Nuclear Information System (INIS)

    A heavy mineral is one with a density that is greater than 2.8 g/cm3. Heavy mineral suites are usually used for determination of provenance and history of sedimentary and metamorphic rocks. The present study is focused on heavy minerals from pyroclastic rocks collected in maars and diatremes from the South Slovakian alkali basalt volcanic field. Practical part describes sampling strategy and methods of heavy mineral separation. Heavy minerals association from maar Hodejov and Filakovo as well as from diatremes Surice and Tachty were studied. The results indicates, that the samples are suitable for further research like geochronology, definition of possible heavy minerals source rocks and sedimentology analyses. This work will help us to get new information about alkali basalt volcanism in Southern Slovakia. (author)

  12. Alginite, an oil shale in basalt maars

    Energy Technology Data Exchange (ETDEWEB)

    Vass, D.; Konecny, V.; Elecko, M. (Technical University, Zvolen (Slovakia). Faculty of Forestry)

    1999-01-01

    A basalt maar situated nearby the village of Pincina (district Lucenec, Southern Slovakia) is filled by alginite. The alginite is a rock rich in organic matter of algal origin. Because of this fact the alginite has the qualities allowing it to be used as a fertiliser or soil activator. The positive qualitites are given by a high humus content (on average 15.5 wt.%), elevated content of macronutrients (P[sub 2]O[sub 5], K[sub 2]O, Ca, Mg) as well as micronutrients. It contains trace elements but toxic heavy metals are below the toxicity limit. The alginite has high water absorption capacity. 3 refs., 4 figs., 3 tabs.

  13. Alginite, an oil shale in basalt maars

    Energy Technology Data Exchange (ETDEWEB)

    Vass, D.; Konecny, V.; Elecko, M. [Technical University, Zvolen (Slovakia). Faculty of Forestry

    1999-11-01

    A basalt maar situated nearby the village of Pincina (district Lucenec, Southern Slovakia) is filled by alginite. The alginite is a rock rich in organic matter of algal origin. Because of this fact the alginite has the qualities allowing it to be used as a fertiliser or soil activator. The positive qualitites are given by a high humus content (on average 15.5 wt.%), elevated content of macronutrients (P{sub 2}O{sub 5}, K{sub 2}O, Ca, Mg) as well as micronutrients. It contains trace elements but toxic heavy metals are below the toxicity limit. The alginite has high water absorption capacity. 3 refs., 4 figs., 3 tabs.

  14. Isotopic and REE studies of lunar basalt 12038: Implications for petrogenesis of aluminous mare basalts

    International Nuclear Information System (INIS)

    We report Sr, Nd, and Sm isotopic studies of lunar basalt 12038, one of the so-called aluminous mare basalts. A precise internal Rb-Sr isochron yields a crystallization age of 3.35 +- 0.09 AE and initial 87Sr/86Sr = 0.69922 +- 2 (2sigma error limits, 1 AE = 109 years, lambda(87Rb) = 0.0139 AE-1). An internal Sm-Nd isochron yields an age of 3.28 +- 0.23 AE and initial 143Nd/144Nd = 0.50764 +- 28. Present-day 143Nd/144Nd is less than the 'chondritic' value, i.e. epsilon(Nd,0) = -2.3 +- O.4 where epsilon(Nd) is the deviation of 143Nd/144Nd from chondritic evolution, expressed as parts in 104. At the time of crystallization epsilon(Nd,3.2 AE) = 1.5 +- 0.6. We have successfully modeled the evolution of the Sr and Nd isotopic compositions and the REE abundances within the framework of our earlier model for Apollo 12 olivine-pigeonite and ilmenite basalts. (orig./HAE)

  15. Study on lithogeochemistry of Middle Jurassic basalts from southern China represented by the Fankeng basalts from Yongding of Fujian Province

    Institute of Scientific and Technical Information of China (English)

    ZHOU; Jincheng; JIANG; Shaoyong; WANG; Xiaolei; YANG; Jinghong; ZHANG; Mengqun

    2006-01-01

    There exists an E-W trending Middle Jurassic volcanic zone in southern China. The Fankeng basalts in the Yongding basin of Fujian Province are considered to be a typical example. The Fankeng basalts have TiO2 contents in the range of 1.92%-3.21%. They are classified as high-Ti basalts. They also have higher total Fe (averaging FeO*= 11.09%). The Middle Jurassic Fankeng basalts from southwestern Fujian have obvious distinctive lithogeochemical features from early Cretaceous basalts from southeastern coast of China. They have higher HFSE, such as Th, Nb, Ta, Zr and Ti. Their element ratios related with HFSE, such as Zr/Ba, La/Nb, La/Ta ,Zr/Y, Ti/Y, Ba/Nb, K/Ti and Rb/Zr are similar to those of OIB. The most samples have εNd(T) of -0.70-0.24, which are near chondrite. Some samples have higher εNd(T) of 1.87-3.55.Therefore, these basaltic magmas might be derived from depleted asthenospheric mantle. The lithogeochemical characteristics of the Fankeng basalts may be caused by interaction between asthenosphere and lithosphere at the time. The (Early-)Middle Jurassic basalts and gabbros from southeastern Hunan, southern Jiangxi and northern Guangdong provinces show similar geochemical features to those of the Fankeng basalts from the Yongding of Fujian. Occurrence of these OIB-type basalts in the area may be regarded as the petrological mark of upwelling of asthenosphere at the time. Upwelling of asthenosphere has led to tectonic extension and the formation of rifted basin in the area.

  16. CO 2-water-basalt interaction. Numerical simulation of low temperature CO 2 sequestration into basalts

    Science.gov (United States)

    Gysi, Alexander P.; Stefánsson, Andri

    2011-09-01

    The interaction between CO 2-rich waters and basaltic glass was studied using reaction path modeling in order to get insight into the water-rock reaction process including secondary mineral composition, water chemistry and mass transfer as a function of CO 2 concentration and reaction progress ( ξ). The calculations were carried out at 25-90 °C and pCO 2 to 30 bars and the results were compared to recent experimental observations and natural systems. A thermodynamic dataset was compiled from 25 to 300 °C in order to simulate mineral saturations relevant to basalt alteration in CO 2-rich environment including revised key aqueous species for mineral dissolution reactions and apparent Gibbs energies for clay and carbonate solid solutions observed to form in nature. The dissolution of basaltic glass in CO 2-rich waters was found to be incongruent with the overall water composition and secondary mineral formation depending on reaction progress and pH. Under mildly acid conditions in CO 2 enriched waters (pH carbonates predominated. Iron, Al and Si were immobile whereas the Mg and Ca mobility depended on the mass of carbonate formed and water pH. Upon quantitative CO 2 mineralization, the pH increased to >8 resulting in Ca-Mg-Fe smectite, zeolites and calcite formation, reducing the mobility of most dissolved elements. The dominant factor determining the reaction path of basalt alteration and the associated element mobility was the pH of the water. In turn, the pH value was determined by the concentration of CO 2 and extent of reaction. The composition of the carbonates depended on the mobility of Ca, Mg and Fe. At pH carbonates with the incorporation of Ca and Mg. At pH >8, the mobility of Fe and Mg was limited due to the formation of clays whereas Ca was incorporated into calcite, zeolites and clays. Competing reactions between clays (Ca-Fe smectites) and carbonates at low pH, and zeolites and clays (Mg-Fe smectites) and carbonates at high pH, controlled the

  17. Basalt-radionuclide distribution coefficient determinations. FY-1979 annual report

    International Nuclear Information System (INIS)

    Experimental radionuclide distribution coefficients (Kd') were determined for Pomona, Flow E, Umtanum basalts, and secondary mineralization associated with Pomona basalt at 230, 600 and 1500C. Radionuclides used were 75Se, 85Sr, 99Tc, 125I, 135Cs, 226Ra, 237Np, 238U, 241Am, and 241Pu. Solution oxygen contents were controlled by the basalt/groundwater system (Eh = 600 to 700 mV), and were high (8.2 to 8.4 mg/l) at 230C. Oxygen contents and pH changed little in contact with basalt. The effects of temperature changes on radionuclide Kd' results varied depending upon the radionuclide involved, solution-solid reactions, and the relationship of the radionuclide to these reactions. For example, cesium Kd' values decreased from 3100 ml/g for Umtanum basalt at 230C to 120 ml/g at 1500C. At the same time, strontium Kd' values increased for Umtanum basalt from 105 ml/g at 230C to complete removal at 1500C and 40 days. Radionuclide adsorption coefficient measurements at higher temperatures and pressures were made in addition to the 230C, solution-solid contact time-conditional Kd (Kd') measurements. These include Kd' measurements with Umtanum basalt, Pomona basalt, Flow E basalt and secondary mineralization and radioisotopes of americium, cesium, iodine, neptunium, plutonium, radium, selenium, strontium, technetium and uranium. The additional temperatures involved were 600C, 1500C, and 3000C. At 1500C, argon pressures of 6.9, 13.8, 20.7, and 27.6 MPa will be used to ascertain the effects of pressure changes on Kd' values. So far only the 6.9 MPa argon pressure has been investigated. The upper temperature of 2500C is where thermal breakdown of dioctahedral smectites (secondary mineralization) begins

  18. Numerical simulation of wear of basalt lava spinning rolls

    Directory of Open Access Journals (Sweden)

    A. Lisiecki

    2006-08-01

    Full Text Available Purpose: of this paper: Results of the study of wear phenomena of cascade spinning rolls during stone woolproduction process are described.Design/methodology/approach: The study was based on direct process observations, chemical analysis andtemperature measurements of basalt lava, metallographic examinations of the spinning rolls deposits. It was showedthat the deposits of spinning rolls are worn in very different way, depending on the roll position in rolls cascade.Findings: Predominant wear phenomena of the fully austenitic Grade 310 deposit of spinning roll no 1 is moltenbasalt lava corrosion-oxidation accompanied by low and high cycle thermal fatigue, high temperature basalt lavaerosion at low velocity of basalt lava stream impinging the working surface at high angle. Predominant wearphenomena of the austenitic-ferritic Grade S32304 deposit of spinning roll no 2 is high temperature basalt lava erosionat very high velocity of lava stream impinging the working surface at high angle what is the cause of much faster wearof then spinning roll no 1. High temperature erosion wear is accompanied by molten basalt lava corrosion-oxidationand low and high cycle thermal fatigue processes. Predominant wear phenomena of the austenitic-ferritic GradeS32304 deposits spinning roll no 3 and roll no 4 is high temperature basalt lava abrasion as sprayed by rolls no 1 andno 2 fibers of solidifying basalt lava impinge the working surface of spinning rolls no 3 and no 4.Research limitations/implications: The mechanisms of high temperature erosion demands further investigationsand detailed studies.Practical implications: The wear resistance of basalt lava spinning rolls can be increased.Originality/value: The mechanisms of surface layer wear of basalt lava spinning rolls were determined.

  19. Basaltic volcanic episodes of the Yucca Mountain region

    International Nuclear Information System (INIS)

    The purpose of this paper is to summarize briefly the distribution and geologic characteristics of basaltic volcanism in the Yucca Mountain region during the last 10--12 Ma. This interval largely postdates the major period of silicic volcanism and coincides with and postdates the timing of major extensional faulting in the region. Field and geochronologic data for the basaltic rocks define two distinct episodes. The patterns in the volume and spatial distribution of these basaltic volcanic episodes in the central and southern part of the SNVF are used as a basis for forecasting potential future volcanic activity in vicinity of Yucca Mountain. 33 refs., 2 figs

  20. Mineral chemistry of Pangidi basalt flows from Andhra Pradesh

    Indian Academy of Sciences (India)

    P V Nageswara Rao; P C Swaroop; Syed Karimulla

    2012-04-01

    This paper elucidates the compositional studies on clinopyroxene, plagioclase, titaniferous magnetite and ilmenite of basalts of Pangidi area to understand the geothermometry and oxybarometry conditions. Petrographic evidence and anorthite content (up to 85%) of plagioclase and temperature estimates of clinopyroxene indicate that the clinopyroxene is crystallized later than or together with plagioclase. The higher An content indicates that the parent magma is tholeiitic composition. The equilibration temperatures of clinopyroxene (1110–1190°C) and titaniferous magnetite and ilmenite coexisting mineral phases (1063–1103°C) are almost similar in lower basalt flow and it is higher for clinopyroxene (900–1110°C) when compared to titaniferous magnetite and ilmenite coexisting mineral phases (748–898°C) in middle and upper basalt flows. From this it can be inferred that the clinopyroxene is crystallized earlier than Fe–Ti oxide phases reequilibration, which indicates that the clinopyroxene temperature is the approximate eruption temperature of the present lava flows. The wide range of temperatures (900–1190°C) attained by clinopyroxene may point out that the equilibration of clinopyroxene crystals initiated from depth till closer to the surface before the melt erupted. Pangidi basalts follow the QFM buffer curve which indicates the more evolved tholeiitic composition. This suggests the parent tholeiitic magma suffered limited fractionation at high temperature under increasing oxygen fugacity in lower basalt flow and more fractionation at medium to lower temperatures under decreasing oxygen fugacity conditions during cooling of middle and upper basalt flows. The variation of oxygen fugacity indicates the oxidizing conditions for lower basalt flow (9.48–10.3) and extremely reducing conditions for middle (12.1–15.5) and upper basalt (12.4–15.54) flows prevailed at the time of cooling. Temperature vs. (FeO+Fe2O3)/(FeO+Fe2O3+MgO) data plots for present

  1. Thicknesses of Mare Basalts from Gravity and Topograhy

    Science.gov (United States)

    GONG, S.; Wieczorek, M.; Nimmo, F.; Kiefer, W.; Head, J.; Smith, D.; Zuber, M.

    2015-10-01

    Mare basalts are derived from partial melting of the lunar interior and are mostly located on the near side of the Moon [1, 2]. Their iron-rich composition gives rise to their dark color, but also causes their density to be substantially higher than normal crustal rocks. The total volume of mare basalts can provide crucial information about the Moon's thermal evolution and volcanic activity. Unfortunately, the thicknesses of the mare are only poorly constrained. Here we use gravity data from NASA's GRAIL mission to investigate the thickness of mare basalts.

  2. Spreading and collapse of big basaltic volcanoes

    Science.gov (United States)

    Puglisi, Giuseppe; Bonforte, Alessandro; Guglielmino, Francesco; Peltier, Aline; Poland, Michael

    2016-04-01

    Among the different types of volcanoes, basaltic ones usually form the most voluminous edifices. Because volcanoes are growing on a pre-existing landscape, the geologic and structural framework of the basement (and earlier volcanic landforms) influences the stress regime, seismicity, and volcanic activity. Conversely, the masses of these volcanoes introduce a morphological anomaly that affects neighboring areas. Growth of a volcano disturbs the tectonic framework of the region, clamps and unclamps existing faults (some of which may be reactivated by the new stress field), and deforms the substratum. A volcano's weight on its basement can trigger edifice spreading and collapse that can affect populated areas even at significant distance. Volcano instability can also be driven by slow tectonic deformation and magmatic intrusion. The manifestations of instability span a range of temporal and spatial scales, ranging from slow creep on individual faults to large earthquakes affecting a broad area. In the frame of MED-SVU project, our work aims to investigate the relation between basement setting and volcanic activity and stability at three Supersite volcanoes: Etna (Sicily, Italy), Kilauea (Island of Hawaii, USA) and Piton de la Fournaise (La Reunion Island, France). These volcanoes host frequent eruptive activity (effusive and explosive) and share common features indicating lateral spreading and collapse, yet they are characterized by different morphologies, dimensions, and tectonic frameworks. For instance, the basaltic ocean island volcanoes of Kilauea and Piton de la Fournaise are near the active ends of long hotspot chains while Mt. Etna has developed at junction along a convergent margin between the African and Eurasian plates and a passive margin separating the oceanic Ionian crust from the African continental crust. Magma supply and plate velocity also differ in the three settings, as to the sizes of the edifices and the extents of their rift zones. These

  3. Structural and geochemical mapping of a Fe-mineralized quartz-mica rich unit in the Ringvassøya Greenstone Belt, West Troms Basement Complex

    OpenAIRE

    Elvenes, Hallgeir

    2015-01-01

    Ringvassøy is one of a chain of large coastal islands representing the Archaean to Paleoproterozoic West Troms Basement Complex (WTBC), west of the Caledonides. On Ringvassøy, a basement of mainly tonalitic gneiss is overlain by the Ringvassøy Greenstone Belt (RGB), which is metamorphosed up to middle amphibolite facies. Tonalitic gneiss in the west and southeast of the island has U–Pb zircon ages of 2.84–2.82 Ga, similar to U–Pb zircon ages of 2.85–2.83 Ga for metavolcanics in the RGB. Mafic...

  4. Age constraints on felsic intrusions, metamorphism and gold mineralisation in the Palaeoproterozoic Rio Itapicuru greenstone belt, NE Bahia State, Brazil

    Science.gov (United States)

    Mello, E.F.; Xavier, R.P.; McNaughton, N.J.; Hagemann, S.G.; Fletcher, I.; Snee, L.

    2006-01-01

    U-Pb sensitive high resolution ion microprobe mass spectrometer (SHRIMP) ages of zircon, monazite and xenotime crystals from felsic intrusive rocks from the Rio Itapicuru greenstone belt show two development stages between 2,152 and 2,130 Ma, and between 2,130 and 2,080 Ma. The older intrusions yielded ages of 2,152??6 Ma in monazite crystals and 2,155??9 Ma in zircon crystals derived from the Trilhado granodiorite, and ages of 2,130??7 Ma and 2,128??8 Ma in zircon crystals derived from the Teofila??ndia tonalite. The emplacement age of the syntectonic Ambro??sio dome as indicated by a 2,080??2-Ma xenotime age for a granite dyke probably marks the end of the felsic magmatism. This age shows good agreement with the Ar-Ar plateau age of 2,080??5 Ma obtained in hornblendes from an amphibolite and with a U-Pb SHRIMP age of 2,076??10 Ma in detrital zircon crystals from a quartzite, interpreted as the age of the peak of the metamorphism. The predominance of inherited zircons in the syntectonic Ambro??sio dome suggests that the basement of the supracrustal rocks was composed of Archaean continental crust with components of 2,937??16, 3,111??13 and 3,162??13 Ma. Ar-Ar plateau ages of 2,050??4 Ma and 2,054??2 Ma on hydrothermal muscovite samples from the Fazenda Brasileiro gold deposit are interpreted as minimum ages for gold mineralisation and close to the true age of gold deposition. The Ar-Ar data indicate that the mineralisation must have occurred less than 30 million years after the peak of the metamorphism, or episodically between 2,080 Ma and 2,050 Ma, during uplift and exhumation of the orogen. ?? Springer-Verlag 2006.

  5. Petrology and structure of greenstone blocks encased in mud-matrix melange of the Franciscan complex near San Simeon, California

    Energy Technology Data Exchange (ETDEWEB)

    Davidsen, R.K.; Cloos, M.

    1985-01-01

    Greenstones comprise about 20% of all mappable (>1 m) blocks encased in blueschist-block-bearing mud-matrix melange exposed in a 10 km-length of sea cliffs near San Simeon. Field and petrographic analysis of 25 blocks show they vary from finely crystalline (<1 mm) locally porphyritic or amygdaloidal, volcanics to coarsely crystalline (1 to 5 mm) diabase. Some are in contact with bedded chert and two have relict pillows. However, most blocks are intensely deformed. Pinch-and-swell and boundinage are recognized on scales from cm to about 10 m. Distortion was accommodated by cataclasis to an aggregate of pieces from mm to m across. Generally, m-sized blocks are pervasively cataclastic whereas larger blocks are crosscut by cataclastic zones that emanate from pervasively cataclastic margins or necked regions of boudins. Discontinuous, cm-thick veins and cavities that are lined by quartz and clacite and rarely, laumontite, prehnite and aragonite locally crosscut all other structures. Relict igneous textures show the primary minerals are plagioclase and clinopyroxene. Abundant secondary minerals, particularly in cataclastic zones, are albite, chlorite, pumpellyite (some have high Al), and calcite. The metamorphic parageneses indicate relatively minor greenschist-facies, sea-floor-type alterations under static conditions followed by lower-temperature alterations synchronous with cataclasis and the development of boudinage. If the blocks are fragments of disrupted ophiolites, only the uppermost section of the suite are present within the mud-matrix melange near San Simeon. The simplest explanation for their crystallization, metamorphism and incorporation into the melange is that they are fragments of seamounts dismembered during subduction.

  6. Calcium Sulfate in Atacama Desert Basalt: A Possible Analog for Bright Material in Adirondack Basalt, Gusev Crater

    Science.gov (United States)

    Sutter, B.; Golden, D. C.; Amundson, R.; Chong-Diaz, G.; Ming, D. W.

    2007-01-01

    The Atacama Desert in northern Chile is one of the driest deserts on Earth (calcium sulfate (Ca-SO4) which was later confirmed by SEM/EDS analysis. This work examines the Ca-SO4 of Atacama basalt in an effort to provide insight into the possible nature of the bright material in the Adirondack basalt of Gusev Crater. The objectives of this work are to (i) discuss variations in Ca-SO4 crystal morphology in the vesicles and (ii) examine the Ca-SO4 interaction(s) with the basalt interior.

  7. Quaternary basaltic volcanism in the Payenia volcanic province, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina

    The extensive Quaternary volcanism in the Payenia volcanic province, Mendoza, Argentina, is investigated in this study by major and trace element analyses, Sr, Nd, Hf and Pb-isotopic analyses and Zr-Hf isotope dilution data on samples from almost the entire province. The samples are mainly...... basalts from all the studied volcanic fields in Payenia is signs of lower crustal contamination indicating assimilation of, in some cases, large amounts of trace element depleted, mafic, plagioclase-bearing rocks. The northern Payenia is dominated by backarc basalts erupted between late Pliocene to late...... Pleistocene times. These basalts mark the end of a period of shallow subduction of the Nazca slab beneath the Payenia province and volcanism in the Nevado volcanic field apparently followed the downwarping slab in a north-northwest direction ending in the Northern Segment. The northern Payenia basalts are...

  8. Petrology of the Apollo 12 pigeonite basalt suite

    International Nuclear Information System (INIS)

    A comparative petrologic study of the Apollo 12 pigeonite basalt suite has been undertaken to answer the following questions: (1) What are the textural and petrologic variations within the pigeonite suite. (2) Are these variations consistent with the hypothesis that the pigeonite basalts are related by crystal fractionation to the olivine basalts. Texturally, the pigeonite basalts range from porphyritic samples with a very fine-grained variolitic groundmass to coarse-grained microgabbro samples with ophitic to graphic textures. The abundances of olivine and Cr-spinel continuously decrease with increasing grain size, whereas the abundances of plagioclase and ilmenite steadily increase. Petrologically, increasing grain size is accompanied by increased Ca in plagioclase, increased Fe in pyroxene, olivine, and spinel, and less Al, Ti, and Cr in pyroxene. All of these changes, including the differences in bulk chemistry can be explained by near-surface fractionation of olivine, pigeonite, and Cr-spinel with the compositions of the observed phenocryst phases

  9. Petrography and chemistry of basalts from the Carlsberg ridge

    Digital Repository Service at National Institute of Oceanography (India)

    Banerjee, R.; Iyer, S.D

    The petrography of the basalts collected in dredge hauls from the Carlsberg Ridge (3 degrees 37'N and 64 degrees 07'E) show systematic variations in their textural and mineralogical assemblages, from an outermost vitreous glassy to a holocrystalline...

  10. Lu-Hf CONSTRAINTS ON THE EVOLUTION OF LUNAR BASALTS.

    Science.gov (United States)

    Fujimaki, Hirokazu; Tatsumoto, Mistunobu

    1984-01-01

    The authors show that a cumulate-remelting model best explains the recently acquired data on the Lu-Hf systematics of lunar mare basalts. The authors model is first constructed using the Lu and Hf concentration data and it is then further strengthened by the Hf isotopic evidence. The authors also show that the similarity of MgO/FeO ratios and the Cr//2O//3 contents between high-Ti and low-Ti basalts, which have been given significance by A. E. Ringwood and D. H. Green are not important constraints for lunar basalt petrogenesis. The authors principal aim is to revive the remelting model for further consideration with the powerful constraints of Lu-Hf systematics of lunar basalts.

  11. Basaltic glass: alteration mechanisms and analogy with nuclear waste glasses

    International Nuclear Information System (INIS)

    A synthetic basaltic glass was dissolved experimentally at 90 deg. C under static conditions in initially pure water. The basaltic glass dissolution rates measured near and far from equilibrium were compared with those of SON 68 nuclear waste glass. Experimental and literature data notably suggested that the alteration mechanisms for the two glasses are initially similar. Under steady-state concentration conditions, the alteration rate decreased of four orders of magnitude below the initial rate (r0). The same alteration rate decrease was observed for basaltic and nuclear glass. These findings tend to corroborate the analogy of the two glasses alteration kinetics. The effect of dissolved silica in solution, observed through dynamic leach tests with silicon-rich solutions, cannot account for the significant drop in the basaltic glass kinetics. Hence, a protective effect of the glass alteration film was assumed and experimentally investigated. Moreover, modeling with LIXIVER argue for a significant effect of diffusion in the alteration gel

  12. Alteration of basaltic glasses from the Central Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.

    Textural, mineralogical and compositional characteristics of basaltic glasses from the Central Indian Ocean show them to be altered to varying extents through their interaction with the seawater, resulting in the formation of palagonite. The major...

  13. Basalt waste isolation project institutional activities

    International Nuclear Information System (INIS)

    The Basalt Waste Isolation Project (BWIP) was established in 1976 as part of the National Waste Terminal Storage Program, and characterization studies to evaluate the Hanford Site have been ongoing since that time. In early 1983, the Nuclear Waste Policy Act (NWPA) became law and established the Office of Civilian Radioactive Waste Management, which includes the BWIP as part of that program. This paper describes the interaction process required by the NWPA and has been ongoing for the past 3 to 4 yr with the State of Washington, Yakima Indian Nation, Confederated Tribes of the Umatilla Indian Reservation, Nez Perce Tribe, other federal agencies, city and county governments, the public and news media, and many other organizations. It identifies the issues that the state and the US Department of Energy (DOE) have noted during the consultation and cooperation (C and C) process. In addition, this paper covers the site recommendation/nomination process for the first repository, including number of sites, location, and types of media being investigated. It covers the site recommendation/nomination process for the second repository, including types of media and where those investigations are being performed. Discussion covering the OCRWM program strategy, which includes documentation being prepared for site recommendation/nomination, site investigations required to determine site suitability, the licensing process for the first repository, etc., are provided

  14. Basalt FRP Spike Repairing of Wood Beams

    Directory of Open Access Journals (Sweden)

    Luca Righetti

    2015-08-01

    Full Text Available This article describes aspects within an experimental program aimed at improving the structural performance of cracked solid fir-wood beams repaired with Basalt Fiber Reinforced Polymer (BFRP spikes. Fir wood is characterized by its low density, low compression strength, and high level of defects, and it is likely to distort when dried and tends to fail under tension due to the presence of cracks, knots, or grain deviation. The proposed repair technique consists of the insertion of BFRP spikes into timber beams to restore the continuity of cracked sections. The experimental efforts deal with the evaluation of the bending strength and deformation properties of 24 timber beams. An artificially simulated cracking was produced by cutting the wood beams in half or notching. The obtained results for the repaired beams were compared with those of solid undamaged and damaged beams, and increases of beam capacity, bending strength and of modulus of elasticity, and analysis of failure modes was discussed. For notched beams, the application of the BFRP spikes was able to restore the original bending capacity of undamaged beams, while only a small part of the original capacity was recovered for beams that were cut in half.

  15. Continuous Basalt Fiber as Reinforcement Material in Polyester Resin

    OpenAIRE

    Jón Ólafur Erlendsson 1973

    2013-01-01

    The industry is always striving to find new and better materials to manufacture new or improved products. Within this context, energy conservation, corrosion, sustainability and other environmental issues are important factors in product development. Basalt fibers are a natural material, produced from igneous rock which can provide high strength relative to weight. Research has also shown that basalt fibers have many other advantageous qualities. This thesis describes an applied research p...

  16. Tensile tests of basalt FRP rebars using chemical anchorages

    OpenAIRE

    Neagoe, Catalin Andrei; Gil Espert, Lluís

    2013-01-01

    In the current report are analyzed the experimental results of initial tensile tests of Basalt FRP (BFRP) rebars provided by VSL. The investigation was conducted in the laboratory of CER LITEM. Objectives of the study: to determine the tensile strengths of 6 mm and 8 mm basalt FRP rebars, and to determine what type of test setup and anchorage system is best suited for future tensile tests of BFRP bars.

  17. Tensile tests of basalt FRP rebars using mechanical anchorages

    OpenAIRE

    Neagoe, Catalin Andrei; Gil Espert, Lluís

    2013-01-01

    In the current report are analyzed the experimental results of initial tensile tests of Basalt FRP (BFRP) rebars provided by VSL. The investigation was conducted on the 19th of February 2013, in the laboratory of CER LITEM. Objectives of the study: to determine the tensile strengths of 6 mm and 8 mm basalt FRP rebars, and to determine what type of test setup and anchorage system is best suited for future tensile tests of BFRP bars.

  18. Investigation of basalt plastic reinforcement and its Adhesion with Concrete

    OpenAIRE

    Kustikova Yulia Olegovna

    2014-01-01

    The load-bearing capacity and durability of concrete structures with metal or other reinforcement depends on their physical and mechanical properties and adhesion values with concrete. In this regard, there is an urgent need in the definition of adhesion of basalt reinforcement and concrete of various compositions and classes. One of the main problems with the use of basalt rods in concrete structures is - providing a high degree of load-carrying capacity in different conditions of stress-str...

  19. Radiolytic hydrogen production in the subseafloor basaltic aquifer

    Directory of Open Access Journals (Sweden)

    Mary E Dzaugis

    2016-02-01

    Full Text Available Hydrogen (H2 is produced in geological settings by dissociation of water due to radiation from radioactive decay of naturally occurring uranium (238U, 235U, thorium (232Th and potassium (40K. To quantify the potential significance of radiolytic H2 as an electron donor for microbes within the South Pacific subseafloor basaltic aquifer, we use radionuclide concentrations of 43 basalt samples from IODP Expedition 329 to calculate radiolytic H2 production rates in basement fractures. The samples are from three sites with very different basement ages and a wide range of alteration types. U, Th and K concentrations vary by up to an order of magnitude from sample to sample at each site. Comparison of our samples to each other and to the results of previous studies of unaltered East Pacific Rise basalt suggests that significant variations in radionuclide concentrations are due to differences in initial (unaltered basalt concentrations (which can vary between eruptive events and post-emplacement alteration. In our samples, there is no clear relationship between alteration type and calculated radiolytic yields. Local maxima in U, Th, and K produce hotspots of H2 production, causing calculated radiolytic rates to differ by up to a factor of 80 from sample to sample. Fracture width also greatly influences H2 production, where microfractures are hotspots for radiolytic H2 production. For example, H2 production rates normalized to water volume are 190 times higher in 1 μm wide fractures than in fractures that are 10 cm wide. To assess the importance of water radiolysis for microbial communities in subseafloor basaltic aquifers, we compare electron transfer rates from radiolysis to rates from iron oxidation in subseafloor basalt. Radiolysis appears likely to be a more important electron donor source than iron oxidation in old (>10 Ma basement basalt. Radiolytic H2 production in the volume of water adjacent to a square cm of the most radioactive SPG basalt may

  20. Radiolytic Hydrogen Production in the Subseafloor Basaltic Aquifer

    Science.gov (United States)

    Dzaugis, Mary E.; Spivack, Arthur J.; Dunlea, Ann G.; Murray, Richard W.; D’Hondt, Steven

    2016-01-01

    Hydrogen (H2) is produced in geological settings by dissociation of water due to radiation from radioactive decay of naturally occurring uranium (238U, 235U), thorium (232Th) and potassium (40K). To quantify the potential significance of radiolytic H2 as an electron donor for microbes within the South Pacific subseafloor basaltic aquifer, we use radionuclide concentrations of 43 basalt samples from IODP Expedition 329 to calculate radiolytic H2 production rates in basement fractures. The samples are from three sites with very different basement ages and a wide range of alteration types. U, Th, and K concentrations vary by up to an order of magnitude from sample to sample at each site. Comparison of our samples to each other and to the results of previous studies of unaltered East Pacific Rise basalt suggests that significant variations in radionuclide concentrations are due to differences in initial (unaltered basalt) concentrations (which can vary between eruptive events) and post-emplacement alteration. However, there is no clear relationship between alteration type and calculated radiolytic yields. Local maxima in U, Th, and K produce hotspots of H2 production, causing calculated radiolytic rates to differ by up to a factor of 80 from sample to sample. Fracture width also greatly influences H2 production, where microfractures are hotspots for radiolytic H2 production. For example, H2 production rates normalized to water volume are 190 times higher in 1 μm wide fractures than in fractures that are 10 cm wide. To assess the importance of water radiolysis for microbial communities in subseafloor basaltic aquifers, we compare electron transfer rates from radiolysis to rates from iron oxidation in subseafloor basalt. Radiolysis appears likely to be a more important electron donor source than iron oxidation in old (>10 Ma) basement basalt. Radiolytic H2 production in the volume of water adjacent to a square cm of the most radioactive SPG basalt may support as many as

  1. Water Content of Basalt Erupted on the ocean floor

    Science.gov (United States)

    Moore, J.G.

    1970-01-01

    Deep sea pillow basalts dredged from the ocean floor show that vesicularity changes with composition as well as with depth. Alkalic basalts are more vesicular than tholeiitic basalts erupted at the same depth. The vesicularity data, when related to experimentally determined solubility of water in basalt, indicate that K-poor oceanic tholeiites originally contained about 0.25 percent water, Hawaiian tholeiites of intermediate K-content, about 0.5 percent water, and alkali-rich basalts, about 0.9 percent water. Analyses of fresh basalt pillows show a systematic increase of H2O+ as the rocks become more alkalic. K-poor oceanic tholeiites contain 0.06-0.42 percent H2O+, Hawaiian tholeiites, 0.31-0.60 percent H2O+, and alkali rich basalts 0.49-0.98 percent H2O+. The contents of K2O, P2O5, F, and Cl increase directly with an increase in H2O+ content such that at 1.0 weight percent H2O+, K2O is 1.58 percent, P2O5 is 0.55 percent, F is 0.07 percent, and Cl is 0.1 percent. The measured weight percent of deuterium on the rim of one Hawaiian pillow is -6.0 (relative to SMOW); this value, which is similar to other indications of magmatic water, suggests that no appreciable sea water was absorbed by the pillow during or subsequent to eruption on the ocean floor. Concentrations of volatile constituents in the alkali basalt melts relative to tholeiitic melts can be explained by varying degrees of partial melting of mantle material or by fractional crystallization of a magma batch. ?? 1970 Springer-Verlag.

  2. Evaluation of basalt flows as a waste isolation medium

    International Nuclear Information System (INIS)

    The Basalt Waste Isolation Program within Rockwell Hanford Operations has the responsibility of conducting studies to determine the feasibility of using the basalt formations, which are in the Pacific Northwest and the Hanford Site, as a site for terminal storage of commercial nuclear waste. This program is divided into systems integration, geology, hydrology, engineered barrier studies, engineering testing, and the construction of a near-surface test facility. Brief descriptions of each task are presented

  3. High alkali-resistant basalt fiber for reinforcing concrete

    International Nuclear Information System (INIS)

    Highlights: • Doping of basalt fiber with ZrSiO4 increased its alkali resistance. • Alkali treatment results in formation of protective surface layer on fibers. • Morphology and chemical composition of surface layer were investigated. • Mechanical properties of fibers were analyzed by a Weibull distribution. • Zirconia doped basalt fibers demonstrate high performance in concrete. - Abstract: Basalt glasses and fibers with zirconia content in the range from 0 to 7 wt% were obtained using ZrSiO4 as a zirconium source. Weight loss and tensile strength loss of fibers after refluxing in alkali solution were determined. Basalt fiber with 5.7 wt% ZrO2 had the best alkali resistance properties. Alkali treatment results in formation of protective surface layer on fibers. Morphology and chemical composition of surface layer were investigated. It was shown that alkali resistance of zirconia doped basalt fibers is caused by insoluble compounds of Zr4+, Fe3+ and Mg2+ in corrosion layer. Mechanical properties of initial and leached fibers were evaluated by a Weibull distribution. The properties of basalt fibers with ZrSiO4 were compared with AR-glass fibers. The performance of concrete with obtained fibers was investigated

  4. Hotspots, basalts, and the evolution of the mantle

    Science.gov (United States)

    Anderson, D. L.

    1981-01-01

    It is noted that the trace element concentration patterns of continental and ocean island basalts and of mid-ocean ridge basalts are complementary. Estimates of the relative sizes of the source regions for these fundamentally different basalt types can be arrived at from the trace element enrichment-depletion patterns. Their combined volume occupies the greater part of the mantle above the 670 km discontinuity. It is pointed out that the source regions separated as a result of early mantle differentiation and crystal fractionation from the resulting melt. The mid-ocean ridge basalts source evolved from an eclogite cumulate that gave up its late-stage enriched fluids at various times to the shallower mantle and continental crust. The mid-ocean ridge basalts source is rich in garnet and clinopyroxene, while the continental and ocean island basalt source is a garnet peridotite that has experienced secondary enrichment. These relationships are found to be consistent with the evolution of a terrestrial magma ocean.

  5. Insulation from basaltic stamp sand. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Williams, F. D.

    1981-04-01

    A Midwest Appropriate Technology Grant was awarded to determine the technical and economic feasibility of producing mineral-fiber insulation directly from extensive deposits of basaltic sand produced during former mining and milling operations in the Keweenaw Peninsula region of Michigan's Upper Peninsula. The amounts of local basaltic sands available and representative chemical compositions were determined. The variation of viscosity with temperature and chemical composition was estimated. Samples were melted and either pulled or blown into fiber. In all cases fiber could be made with a reasonable tensile strength to ensure usefulness. It was concluded that it was technically feasible to produce fibers from basaltic stamp sands of the Upper Peninsula of Michigan. A technical feasibility study using published data, a cost and design analysis of a basalt fiber production plant, a market survey of fiber needs, and an economic analysis for investing in a basalt fiber venture was undertaken. These studies concluded that the local production of basaltic insulation was both feasible and economically reasonable. It was suggested that the plant be located in a region of greater population density with lower utility costs. A representative one-third of these studies is included as appendices A, B, C, and D.

  6. Sensitivity of geochemical monitoring for CO2 sequestration in basalt

    Science.gov (United States)

    Zakharova, N. V.; Goldberg, D.; Herron, M.; Grau, J.

    2010-12-01

    Continental flood basalts is a promising target for carbon dioxide (CO2) storage due to high storage capacity, presence of seals, and potential for geochemical trapping which results in binding CO2 into stable carbonate minerals. The success of long-term CO2 storage in igneous rocks highly depends on our ability to monitor mineralization under in situ conditions. The direct chemistry measurements on cores are costly and typically do not provide continuous coverage. In this study we investigate the potential of borehole geochemical logging for monitoring of CO2 mineralization in basalt. Neutron-induced capture gamma ray spectroscopy tools allow obtaining in-situ concentration logs for up to 10 major elements which can be used to construct a quantitative mineralogical model. While this usually provides good bulk mineralogy estimates, detecting small-volume mineral alteration in volcanic rocks remains challenging, especially if borehole conditions are poor. We analyze Schlumberger Elemental Capture Spectroscopy logs and chemical core analysis from the pilot CO2 sequestration project in the Columbia River flood basalt. We use the geochemical spectroscopy logs and quantitative modeling to quantify their sensitivity to secondary mineralization in basalt. We apply statistical analysis to explain the variance in elemental concentrations (and other logs) and establish detection limits for various mineral alteration products in basalt. We use these results to evaluate monitoring capabilities and limitations of geochemical logging for CO2 mineralization after underground injection in basalt and suggest areas for future research.

  7. A basalt trigger for the 1991 eruptions of Pinatubo volcano?

    Science.gov (United States)

    Pallister, J.S.; Hoblitt, R.P.; Reyes, A.G.

    1992-01-01

    THE eruptive products of calc-alkaline volcanos often show evidence for the mixing of basaltic and acid magmas before eruption (see, for example, refs 1, 2). These observations have led to the suggestion3 that the injection of basaltic magma into the base of a magma chamber (or the catastrophic overturn of a stably stratified chamber containing basaltic magma at its base) might trigger an eruption. Here we report evidence for the mixing of basaltic and dacitic magmas shortly before the paroxysmal eruptions of Pinatubo volcano on 15 June 1991. Andesitic scoriae erupted on 12 June contain minerals and glass with disequilibrium compositions, and are considerably more mafic than the dacitic pumices erupted on 15 June. Differences in crystal abundance and glass composition among the pumices may arise from pre-heating of the dacite magma by the underlying basaltic liquid before mixing. Degassing of this basaltic magma may also have contributed to the climatologically important sulphur dioxide emissions that accompanied the Pinatubo eruptions.

  8. Basaltic Lava Flow vs. Welded Basaltic Ignimbrite: Determining the Depositional Nature of a Volcanic Flow in the Akaroa Volcanic Complex

    Science.gov (United States)

    Sexton, E. A.; Hampton, S.

    2014-12-01

    Welded basaltic ignimbrites are one of the rarest forms of ignimbrites found on Earth and can often have characteristics that are indistinguishable from those of basaltic lava flows. This study evaluates a basaltic volcanic flow in a coastal cliff sequence in Raupo Bay, Akaroa Volcanic Complex, Banks Peninsula, New Zealand. The Raupo Bay coastal cliff sequence is comprised of 4 units, termed L1, L2, L3, and A, capped by loess. L1 and L2 are basaltic lavas, L3 proximal scoria deposits, which thin inland, and Unit A, a flow with unusual characteristics, which is the focus of this study. Field mapping, sampling, geochemical analysis and petrology were utilized to characterize units. Further detailed structural analysis of Unit A was completed, to determine the nature of the basal contact, variations in welding throughout the unit and the relationship of the layer to the underlying topography. From these analyses it was found: Unit A is thickest in a paleo-valley and thins and mantles higher topography, welding in the unit increases downwards forming topographic controlled columnar jointing, the top of the unit is brecciated and grades into the lower welded/jointed portion, the basal contact is sharp overlying a regional airfall deposit, the unit has a notably distinct geochemical composition from the underlying stratigraphic units, Unit A contains flattened and sheared scoria clasts, has aligned bubbles, and lava lithics. Further thin section analysis of Unit A identified flattened clast boundaries and microlite rimming around phenocrysts. In comparing these features to previous studies on basaltic lavas and ignimbrites it is hypothesized that Unit A is a welded basaltic ignimbrite that was channelized by paleo-topography on the outer flanks of the Akaroa Volcanic Complex. This study furthers the characterization of basaltic ignimbrites and is the first to recognize basaltic ignimbrites within the Akaroa Volcanic Complex.

  9. U-Pb SHRIMP ages of detrital zircons from Hiriyur formation in Chitradurga Greenstone belt and its implication to the Neoarchean evolution of Dharwar craton, South India

    International Nuclear Information System (INIS)

    We report newly obtained U-Pb SHRIMP ages of detrital zircons from metagreywackes in the Hiriyur Formation (Chitradurga Group, Dharwar Supergroup) from the central eastern part of the Chitradurga greenstone belt. U-Pb analyses yield three major Neoarchean age populations ranging from 2.70 - 2.54 Ga with some minor age population of Mesoarchean. The maximum age of deposition is constrained by the youngest detrital zircon population at 2546 Ma. This is the first report of the occurrence of supracrustal rocks less than 2.58 Ga in the central part of Chitradurga greenstone belt. Close evaluation of detrital ages with the published ages of surrounding igneous rocks suggest that the youngest detrital zircons might be derived from rocks of the Eastern Dharwar craton and the inferred docking of the western and eastern Dharwar cratons happened prior to the deposition of the Hiriyur Formation. The Chitradurga shear zone, dividing the Dharwar craton into western and eastern blocks, probably developed after the deposition. Furthermore, the lower intercept is interpreted as evidence for the Pan-African overprints in the study area. (author)

  10. Vapor segregation and loss in basaltic melts

    Science.gov (United States)

    Edmonds, M.; Gerlach, T.M.

    2007-01-01

    Measurements of volcanic gases at Pu'u'O??'o??, Kilauea Volcano, Hawai'i, reveal distinct degassing regimes with respect to vapor segregation and loss during effusive activity in 2004-2005. Three styles of vapor loss are distinguished by the chemical character of the emitted volcanic gases, measured by open path Fourier transform infrared spectroscopy: 1 persistent continuous gas emission, 2 gas piston events, and 3 lava spattering. Persistent continuous gas emission is associated with magma ascent and degassing beneath the crater vents, then eruption of the degassed magma from flank vents. Gas piston events are the result of static gas accumulation at depths of 400-900 m beneath Pu'u'O??'o??. A CO2-rich gas slug travels up the conduit at a few meters per second, displacing magma as it expands. Lava spattering occurs due to dynamic bubble coalescence in a column of relatively stagnant magma. The Large gas bubbles are H2O rich and are generated by open-system degassing at depths of segregation in basaltic melts, but their implications differ. Accumulation and segregation of CO2-rich vapor at depth does not deplete the melt of H2O (required to drive lava fountains near to the surface) and therefore gas piston events can occur interspersed with lava fountaining activity. Lava spattering, however, efficiently strips H2O-rich vapor from magma beneath the crater vents; the magma must then erupt effusively from vents on the flank of the cone. ?? 2007 The Geological Society of America.

  11. Spinifex-textured komatiites in the south border of the Carajas ridge, Selva Greenstone belt, Carajás Province, Brazil

    Science.gov (United States)

    Siepierski, Lincoln; Ferreira Filho, Cesar Fonseca

    2016-03-01

    Spinifex-textured komatiites in the Selva greenstone belt are the first unequivocal examples of komatiites in the Transition Subdomain of the Carajás Mineral Province. Outcrops of spinifex-textured komatiites, located ∼1.5 km to the south of the Carajás ridge, were discovered during regional exploration for Ni-Cu-(PGE) sulfide deposits by VALE. They are associated with a 3.8 km long unit consisting of variable types of ultramafic rocks (talc schist, serpentinite and spinifex-textured komatiite). This ultramafic unit follows the steep dipping NW-SE trending Selva greenstone belt composed mainly by quartz-chlorite schists (interpreted as metasediments) and chlorite-actinolite schists (interpreted as metabasalts). Greenschist facies metamorphic parageneses characterize all rock types in the Selva greenstone belt. The komatiitic rocks in the Selva belt comprise a sequence of flows consisting of an upper spinifex-textured layer and a lower olivine cumulate layer. Although the spinifex and cumulus textures are well preserved in the field, the primary mineralogy of the komatiites has been completely replaced by greenschist facies metamorphic minerals. Platy olivine spinifex texture, consisting of an array of roughly parallel olivine plates, and random spinifex texture, consisting of randomly oriented olivine plates, are the most common primary volcanic textures in komatiites in the Selva greenstone belt. Platy and random spinifex texture is defined by former plates of olivine replaced by serpentine with minor actinolite, chlorite and magnetite, alternating with former matrix replaced by abundant actinolite and minor chlorite, talc, serpentine, and magnetite. The domains between olivine plates in both platy and random spinifex-textured rocks contain irregular arrays of fine-grained parallel crystals, representing primary fine-grained "quench" clinopyroxene crystals replaced by actinolite. Spinifex-textured komatiites have MgO contents bracket between 22.8 and 26.9 wt

  12. Surface oxidization-reduction reactions in Columbia Plateau basalts

    International Nuclear Information System (INIS)

    Results are presented which define principal oxidation-reduction reactions expected between ground water and iron in the Umtanum and Cohassett basalt flows of south central Washington. Data include kinetics of aqueous iron speciation, rates of O2 uptake and nature of oxyhydroxide precipitates. Such data are important in predicting behavior of radionuclides in basalt aquifers including determination of valence states, speciation, solubility, sorption, and coprecipitation on iron oxyhydroxide substrates and colloids. Analyses of the basalt by XPS indicates that ferrous iron is oxidized to ferric iron on the surface and that the total iron decreases as a function of pH during experimental weathering. Iron oxyhydroxide phases did not form surface coating on basalt surfaces but rather nucleated as separate plases in solution. No significant increases in Cs or Sr sorption were observed with increased weathering of the basalt. Concurrent increases in Fe(II) and decreases in Fe(III) in slightly to moderately acid solutions indicated continued oxidization of ferrous iron in the basalt. At neutral to basic pH, Fe(II) was strongly sorbed onto the basalt surface (Kd = 6.5 x 10-3 1 x m2) resulting in low dissolved concentrations even under anoxic conditions. The rate of O2 uptake increased with decreasing pH. Diffusion rates (-- 10-14 cm2 x s-1), calculated using a one-dimensional analytical model, indicate grain boundary diffusion. Comparisons of Eh values calculated by Pt electrode, dissolved O2 and Fe(II)/Fe(III) measurements showed considerable divergence, with the ferric-ferrous couple being the preferred method of estimating Eh

  13. Elastic laboratory measurements and modeling of saturated basalts

    Science.gov (United States)

    Adam, Ludmila; Otheim, Thomas

    2013-03-01

    Understanding the elastic behavior of basalt is important to seismically monitor volcanoes, subsea basalts, and carbon sequestration in basalt. We estimate the elastic properties of basalt samples from the Snake River Plain, Idaho, at ultrasonic (0.8 MHz) and seismic (2-300 Hz) frequencies. To test the sensitivity of seismic waves to the fluid content in the pore structure, measurements are performed at three saturation conditions: saturated with liquid CO2, water, and dry. When CO2 replaces water, the P-wave velocity drops, on average, by 10%. Vesicles and cracks, observed in the rock microstructure, control the relaxation of pore-fluid pressures in the rock as a wave propagates. The bulk and shear moduli of basalts saturated with liquid CO2 are not frequency dependent, suggesting that fluid pore pressures are in equilibrium between 2 Hz and 0.8 MHz. However, when samples are water saturated, the bulk modulus of the rock is frequency dependent. Modeling with Gassmann's equations predicts the measured saturated rock bulk modulus for all fluids for frequencies below 20 Hz but underpredicts the water-saturated basalt bulk modulus for frequencies greater than 20 Hz. The most likely reason is that the pore-fluid pressures are unrelaxed. Instead, the ultrasonic frequency rock moduli are modeled with high-frequency elastic theories of squirt flow and Kuster-Toksöz (KT). Although KT's model is based on idealized pore shapes, a combination of spheres (vesicles) and penny-shaped cracks (fractures) interpreted and quantified from petrographical data predicts the ultrasonic dry and saturated rock moduli for the measured basalts.

  14. The rheological behavior of fracture-filling cherts: example of Barite Valley dikes, Barberton Greenstone Belt, South Africa

    Directory of Open Access Journals (Sweden)

    M. Ledevin

    2014-05-01

    Full Text Available A 100 m-thick complex of near-vertical carbonaceous chert dikes marks the transition from the Mendon to Mapepe Formations (3260 Ma in the Barberton Greenstone Belt, South Africa. Fracturing was intense in this area, as shown by the profusion and width of the dikes (ca. 1 m on average and by the abundance of completely shattered rocks. The dike-and-sill organization of the fracture network and the upward narrowing of some of the large veins indicate that at least part of the fluid originated at depth and migrated upward in this hydrothermal plumbing system. Abundant angular fragments of silicified country rock are suspended and uniformly distributed within the larger dikes. Jigsaw-fit structures and confined bursting textures indicate that hydraulic fracturing was at the origin of the veins. The confinement of the dike system beneath an impact spherule bed suggests that the hydrothermal circulations were triggered by the impact and located at the external margin of a large crater. From the geometry of the dikes and the petrography of the cherts, we infer that the fluid that invaded the fractures was thixotropic. On one hand, the injection of black chert into extremely fine fractures is evidence for low viscosity at the time of injection; on the other hand, the lack of closure of larger veins and the suspension of large fragments in a chert matrix provide evidence of high viscosity soon thereafter. The inference is that the viscosity of the injected fluid increased from low to high as the fluid velocity decreased. Such rheological behavior is characteristic of media composed of solid and colloidal particles suspended in a liquid. The presence of abundant clay-sized, rounded particles of silica, carbonaceous matter and clay minerals, the high proportion of siliceous matrix and the capacity of colloidal silica to form cohesive 3-D networks through gelation, account for the viscosity increase and thixotropic behavior of the fluid that filled the

  15. The rheological behavior of fracture-filling cherts: example of Barite Valley dikes, Barberton Greenstone Belt, South Africa

    Science.gov (United States)

    Ledevin, M.; Arndt, N.; Simionovici, A.

    2014-05-01

    A 100 m-thick complex of near-vertical carbonaceous chert dikes marks the transition from the Mendon to Mapepe Formations (3260 Ma) in the Barberton Greenstone Belt, South Africa. Fracturing was intense in this area, as shown by the profusion and width of the dikes (ca. 1 m on average) and by the abundance of completely shattered rocks. The dike-and-sill organization of the fracture network and the upward narrowing of some of the large veins indicate that at least part of the fluid originated at depth and migrated upward in this hydrothermal plumbing system. Abundant angular fragments of silicified country rock are suspended and uniformly distributed within the larger dikes. Jigsaw-fit structures and confined bursting textures indicate that hydraulic fracturing was at the origin of the veins. The confinement of the dike system beneath an impact spherule bed suggests that the hydrothermal circulations were triggered by the impact and located at the external margin of a large crater. From the geometry of the dikes and the petrography of the cherts, we infer that the fluid that invaded the fractures was thixotropic. On one hand, the injection of black chert into extremely fine fractures is evidence for low viscosity at the time of injection; on the other hand, the lack of closure of larger veins and the suspension of large fragments in a chert matrix provide evidence of high viscosity soon thereafter. The inference is that the viscosity of the injected fluid increased from low to high as the fluid velocity decreased. Such rheological behavior is characteristic of media composed of solid and colloidal particles suspended in a liquid. The presence of abundant clay-sized, rounded particles of silica, carbonaceous matter and clay minerals, the high proportion of siliceous matrix and the capacity of colloidal silica to form cohesive 3-D networks through gelation, account for the viscosity increase and thixotropic behavior of the fluid that filled the veins. Stirring and

  16. Geochemistry of the metavolcanic rocks in the vicinity of the MacLellan Au-Ag deposit and an evaluation of the tectonic setting of the Lynn Lake greenstone belt, Canada: Evidence for a Paleoproterozoic-aged rifted continental margin

    Science.gov (United States)

    Glendenning, Michael W. P.; Gagnon, Joel E.; Polat, Ali

    2015-09-01

    The Paleoproterozoic (ca. 1900 Ma) Lynn Lake greenstone belt of northern Manitoba, Canada, has been previously characterized as comprising a series of tectonically juxtaposed intra-oceanic-derived metavolcanic rocks. The results of more recent local and regional studies, however, support a significant contribution of continental crust during formation of the metasedimentary, metavolcanic, and intrusive igneous rocks that comprise the majority of the Lynn Lake greenstone belt. The tectonic model previously proposed for the Lynn Lake greenstone belt, however, did not consider the geodynamics of the Lynn Lake greenstone belt in the context of all available data. In this study, we report the results of outcrop mapping and petrographic analysis, as well as major, minor, and trace element geochemical analyses for 54 samples from the Northern terrane, and integrate and compare the results with data from previously published studies. These data are used to recharacterize the metavolcanic rocks and to develop a new geodynamic model for the formation of the Lynn Lake greenstone belt. Ultramafic to intermediate rocks in the vicinity of the MacLellan Au-Ag deposit are characterized primarily by E-MORB-like trace element characteristics and Th-Nb-La systematics, which are interpreted to be the result of a primary, plume-derived melt interacting with continental lithosphere at a thinned (i.e., rifted) continental margin. Similarly, the majority of the mafic to intermediate rocks that comprise the Lynn Lake greenstone belt are characterized by flat to E-MORB-like trace element patterns and Th-Nb-La systematics, which are consistent with mantle plume-derived, contaminated, oceanic continental rift or rifted margin setting rocks. This study suggests that the metavolcanic rocks of the Lynn Lake greenstone belt were derived via rifting between the Superior and Hearne Cratons, which resulted in the formation and growth of the Manikewan Ocean. Alternatively, the metavolcanic rocks

  17. Preliminary Hydrogeologic Characterization Results from the Wallula Basalt Pilot Study

    Energy Technology Data Exchange (ETDEWEB)

    B.P. McGrail; E. C. Sullivan; F. A. Spane; D. H. Bacon; G. Hund; P. D. Thorne; C. J. Thompson; S. P. Reidel; F. S. Colwell

    2009-12-01

    The DOE's Big Sky Regional Carbon Sequestration Partnership has completed drilling the first continental flood basalt sequestration pilot borehole to a total depth (TD) of 4,110 feet on the Boise White Paper Mill property at Wallula, Washington. Site suitability was assessed prior to drilling by the 2007-2008 acquisition, processing and analysis of a four-mile, five-line three component seismic swath, which was processed as a single data-dense line. Analysis of the seismic survey data indicated a composite basalt formation thickness of {approx}8,000 feet and absence of major geologic structures (i.e., faults) along the line imaged by the seismic swath. Drilling of Wallula pilot borehole was initiated on January 13, 2009 and reached TD on April 6, 2009. Based on characterization results obtained during drilling, three basalt breccia zones were identified between the depth interval of 2,716 and 2,910 feet, as being suitable injection reservoir for a subsequent CO2 injection pilot study. The targeted injection reservoir lies stratigraphically below the massive Umtanum Member of the Grande Ronde Basalt, whose flow-interior section possesses regionally recognized low-permeability characteristics. The identified composite injection zone reservoir provides a unique and attractive opportunity to scientifically study the reservoir behavior of three inter-connected reservoir intervals below primary and secondary caprock confining zones. Drill cuttings, wireline geophysical logs, and 31one-inch diameter rotary sidewall cores provided geologic data for characterization of rock properties. XRF analyses of selected rock samples provided geochemical characterizations of the rocks and stratigraphic control for the basalt flows encountered by the Wallula pilot borehole. Based on the geochemical results, the pilot borehole was terminated in the Wapshilla Ridge 1 flow of the Grande Ronde Basalt Formation. Detailed hydrologic test characterizations of 12 basalt interflow

  18. Deep Metamorphic Rock Series of Bayan Wula-mountain Granite-greenstone Belt and Gold MineralizationMA Runze%巴彦乌拉山深变质岩系的花岗-绿岩带与金成矿

    Institute of Scientific and Technical Information of China (English)

    胡晰; 马润则; 陈志耕; 张腊梅; 陈娟; 刘颖倩

    2015-01-01

    A large area of Archean granite - greenstone belt exposed in Bayan wula-mountain, which bedrock outcrops good. Survey area′greenstone belt is existing as the green schist facies of tectonic schist. At present, domestic and foreign atta-ches great importance to the study of granite greenstone belt, The major reason is that research on it has mineral and geological sig-nificance. However, Gold directly affecting the financial securi-ty of the country as a precious metal, which is very important for the national economy stability. Granite - greenstone belt has a close relation with gold deposit. At present, China 's most im-portant gold producing type is greenstone type gold deposit.%巴彦乌拉山出露大面积的太古代花岗-绿岩带,基岩出露良好。本区的绿岩带是以变质程度为绿片相的构造片岩形式出现的。国内外对花岗绿岩带的研究非常重视,主要是因为其研究对矿产和地质都具有重大意义。然而金为直接影响国家金融安全的贵重金属,对于国家的经济稳定有极其重要的作用。其中花岗-绿岩带与金成矿有着密切关系。目前我国主要的产金类型为绿岩型金矿。

  19. Stratigraphy of Oceanus Procellarum basalts - Sources and styles of emplacement

    Science.gov (United States)

    Whitford-Stark, J. L.; Head, J. W., III

    1980-01-01

    The basaltic fill of Oceanus Procellarum has been formally subdivided into four lithostratigraphic formations: The Repsold Formation, the Telemann Formation, the Hermann Formation, and the Sharp Formation. The Repsold Formation is composed of high-Ti basalts and pyroclastic deposits with an estimated age of 3.75 + or - 0.05 b.y. and an estimated volume of about 2.1 x 10 to the 5th cu km. This is overlain by the Telemann Formation composed of very low-Ti basalts and pyroclastic deposits with an estimated age of 3.6 + or - 0.2 b.y. and a volume of 4.2 x 10 to the 5th cu km. The Hermann Formation, composed of intermediate basalts with an estimated age of 3.3 + or - 0.3 b.y., represents the next youngest unit with an estimated volume of 2.2 x 10 to the 5th cu km. The youngest materials in Procellarum are the medium-to-high-Ti basalts comprising the Sharp Formation with an estimated age of 2.7 + or - 0.7 b.y. and a volume of 1.8 x 10 to the 4th cu km.

  20. Emanation-thermal analysis of basalt fiber adsorbents

    International Nuclear Information System (INIS)

    Complex emanation-thermal analysis is used for investigating structural changes in basalt adsorbents taking place during thermal affects on material. Adsorbent is prepared by two-stage treatment of staple basalt fibers by hydrochloric acid. Isotherms of sorption of liquid nitrogen vapors by new sorbents are measured. Areas of the open surface, porosity and pores size spectra of leached fibers are calculated. It is determined by the method of thermostimulated gassing that adsorbed water is in two energetically different states in porous basalt fiber: basic part of water vapors is desorbed at 90-110 Deg C, remained part -at 300-320 Deg C. Full regeneration of sorbent requires warming up to 550 Deg C

  1. Corrosion and tribological properties of basalt fiber reinforced composite materials

    Science.gov (United States)

    Ha, Jin Cheol; Kim, Yun-Hae; Lee, Myeong-Hoon; Moon, Kyung-Man; Park, Se-Ho

    2015-03-01

    This experiment has examined the corrosion and tribological properties of basalt fiber reinforced composite materials. There were slight changes of weight after the occurring of corrosion based on time and H2SO4 concentration, but in general, the weight increased. It is assumed that this happens due to the basalt fiber precipitate. Prior to the corrosion, friction-wear behavior showed irregular patterns compared to metallic materials, and when it was compared with the behavior after the corrosion, the coefficient of friction was 2 to 3 times greater. The coefficient of friction of all test specimen ranged from 0.1 to 0.2. Such a result has proven that the basalt fiber, similar to the resin rubber, shows regular patterns regardless of time and H2SO4 concentration because of the space made between resins and reinforced materials.

  2. Basalt woven fiber reinforced vinylester composites: Flexural and electrical properties

    International Nuclear Information System (INIS)

    A preliminary comparative study of basalt and E-glass woven fabric reinforced composites was performed. The fabrics were characterized by the same weave pattern and the laminates tested by the same fiber volume fraction. Results of the flexural and interlaminar characterization are reported. Basalt fiber composites showed higher flexural modulus and apparent interlaminar shear strength (ILSS) in comparison with E-glass ones but also a lower flexural strength and similar electrical properties. With this fiber volume fraction, scanning electron microscopy (SEM) analysis of the fractured surfaces enabled a better understanding both of the failure modes involved and of points of concern. Nevertheless, the results of this study seem promising in view of a full exploitation of basalt fibers as reinforcement in polymer matrix composites (PMCs).

  3. Investigation of basalt plastic reinforcement and its Adhesion with Concrete

    Directory of Open Access Journals (Sweden)

    Kustikova Yulia Olegovna

    2014-03-01

    Full Text Available The load-bearing capacity and durability of concrete structures with metal or other reinforcement depends on their physical and mechanical properties and adhesion values with concrete. In this regard, there is an urgent need in the definition of adhesion of basalt reinforcement and concrete of various compositions and classes. One of the main problems with the use of basalt rods in concrete structures is - providing a high degree of load-carrying capacity in different conditions of stress-strain state of the structure, and the related amount of its adhesion with concrete. Meeting these requirements can be achieved with load-bearing capacity of individual rods, adhesion value, in general, of basalt reinforcement with concrete.

  4. Magnetic properties of Martian olivine basalts studied by terrestrial analogues

    International Nuclear Information System (INIS)

    Here we present a comparison study of terrestrial olivine basalt and relatively un-weathered basalt studied by the Mars Exploration Rover Spirit on Mars. The Moessbauer spectra of terrestrial olivine basalt exhibit some characteristics that can also be seen in the Mars spectra. The results from Moessbauer spectroscopy on Mars indicate that the olivine in the rocks has undergone alteration at high temperatures (600-1,000 deg. C), a process known to give rise to anomalously magnetic rocks on Earth. This suggests that if the rocks at Gusev crater had solidified in an external magnetic field of terrestrial magnitude, these would have become highly magnetic enough to explain the presence of magnetic anomalies on Mars.

  5. Petrogenesis of pillow basalts from Baolai in southwestern Taiwan

    Science.gov (United States)

    Liu, Chih-Chun; Yang, Huai-Jen

    2016-04-01

    The pillow basalts from Baolai in southwestern Taiwan have been inferred to bear Dupal signautres based on their Th/Ce ratio, linking the Baolai basalts to the South China Sea (SCS) seamounts that are characterized by Dupal Pb isotope signatures (Smith and Lewis, 2007). In this study, thirty-two Baolai basalt samples were analyzed for abundances of major and trace elements as well as Pb and Nd isotope ratios to verify their Dupal characters and to constrain their petrogenesis significance. The Baolai basalts contain 4-10 % L.O.I.. Three stages of alteration are inferred from plots of L.O.I. abundance versus concentrations major oxides as well as mineral textures and compositions. The first alteration stage was characterized by albitization that converted Ca-rich plagioclase to albite. The second alteration stage was dominated by chloritization of olivine and augite, resulting in increases in L.O.I. abundance. The last alteration stage is represented by formation of secondary calcite in vesicles and cracks. These alteration processes reflect interaction with seawater and apparently did not affect the magmatic Pb isotope composition for the low Pb concentration in seawater. Relative to the North Hemisphere Reference Line (NHRL), the Baolai pillow basalts have higher 208Pb/204Pb ratios at a given 206Pb/204Pb value, showing Dupal anomaly. For their relatively higher 208Pb/204Pb, 207Pb/204Pb, and 206Pb/204Pb ratios, the Baolai basalts are distinct from majority of the Cenozoic basalts in the Hainan-Leizhou peninsula, the Indochina peninsula, and the SCS seamounts, for which derivation from the Hainan mantle plume has been recently proposed (Wang et al., 2013). In contrast, the Baolai basalts and the Cenozoic basalts from eastern Guangdong at southeastern China have similar Pb and Nd isotope compositions, indicating derivation from similar mantle sources. However, the Baolai basalts have lower abundance ratios of Zr/Hf (40.3-45.6 versus 46.5-50.5), La/Yb (12

  6. Zr and Nb partition coefficients: implications for the genesis of mare basalts, kreep, and sea floor basalts

    International Nuclear Information System (INIS)

    The distribution coefficients for Zr and Nb have been determined between armalcolite, ilmenite, clinopyroxene, rutile, plagioclase and a coexisting synthetic high Ti mare basalt melt at 11050, 11130 and 11280C and at f02 = IW x 10sup(-0.5). Recommended values are D(Zr) ilm/liq = 0.28, D(Zr) arm/liq = 1.2, D(Zr) cpx/liq = 0.05 to 0.22, D(Zr)plag/liq 2O3 in the melt being an important controlling parameter. On the basis of the measured distribution coefficients and existing analytical data, the following conclusions can be drawn: (1) Apollo 11(low K) and Apollo 17 high Ti mare basalts have been generated by the partial melting of an ilmenite-rich cumulate. (2) Apollo 11 (high K) mare basalts have been generated by a small degree of partial melting of a more fractionated ilmenite-rich cumulate. (3) KREEP basalt magmas may have formed as residual melts produced by extensive fractional crystallization of the lunar magma ocean. (4) Anomalous (Type 11) mid-ocean ridge basalts may have been generated by small degrees of partial melting of a relatively undepleted mantle with clinopyroxene remaining in the residuum. (author)

  7. Basalt fiber reinforced polymer composites: Processing and properties

    Science.gov (United States)

    Liu, Qiang

    A high efficiency rig was designed and built for in-plane permeability measurement of fabric materials. A new data derivation procedure to acquire the flow fluid pattern in the experiment was developed. The measurement results of the in-plane permeability for basalt twill 31 fabric material showed that a high correlation exists between the two principal permeability values for this fabric at 35% fiber volume fraction. This may be the most important scientific contribution made in this thesis. The results from radial measurements corresponded quite well with those from Unidirectional (UD) measurements, which is a well-established technique. No significant differences in mechanical properties were found between basalt fabric reinforced polymer composites and glass composites reinforced by a fabric of similar weave pattern. Aging results indicate that the interfacial region in basalt composites may be more vulnerable to environmental damage than that in glass composites. However, the basalt/epoxy interface may have been more durable than the glass/epoxy interface in tension-tension fatigue because the basalt composites have significantly longer fatigue life. In this thesis, chapter I reviews the literature on fiber reinforced polymer composites, with concentration on permeability measurement, mechanical properties and durability. Chapter II discusses the design of the new rig for in-plane permeability measurement, the new derivation procedure for monitoring of the fluid flow pattern, and the permeability measurement results. Chapter III compares the mechanical properties and durability between basalt fiber and glass fiber reinforced polymer composites. Lastly, chapter IV gives some suggestions and recommendations for future work.

  8. Flood basalt volcanism on the Moon and Mars

    International Nuclear Information System (INIS)

    Comparative studies of the surfaces of the terrestrial planets reveal that processes of flood basalt volcanism were common to all of them, irrespective of their stages of evolution either primitive, intermediate or progressive. On the Moon manifestations of flood basalt volcanism have been recognized in basins (maria); on the planet Mars both in basins (planitiae) and in higher topographic (continental) levels. The mare-epoch of the less developed planets led to significant changes in their relief and in the crustal structure. Examples of volcanic flows from the lunar and martian surface are introduced. Some crustal uplifts on Mars can be interpreted in terms of Van Bemmelen's undations. (Auth.)

  9. Genetic aspects of basalts from the Carlsberg Ridge

    Digital Repository Service at National Institute of Oceanography (India)

    Banerjee, R.; Iyer, S.D.

    of the plagioclase from a basaltic magma at a slower rate than the co - precipitating olivine and/or pyroxenes, due to the high - pressure effect 33 or density dif - ferences between plagiocl ase and the basaltic magma 34 . Plagioclase phenocrysts with An - rich... show no zoned mineral, while those that ascend slowly are more likely to cool extensively and have zoned phenocrysts. Further, the size of the magma chambers could also have an effect in th ose lavas that originated from a large, thermally he...

  10. Statistical evaluation of some Columbia River basalt chemical analyses

    International Nuclear Information System (INIS)

    This study had a threefold purpose: to examine the atomic absorption gamma spectroscopy, emission spectroscopy, and neutron activation data accumulated by Atlantic Richfield Hanford Company through 1976 (predecessor company to Rockwell Hanford Operations), and evaluate the precision of the data and their calibration reliability; to determine from these chemical data those elements that were best for characterizing basalt flows for correlation purposes; and, to use these chemical data to establish statistical correlations among type locality reference groups and the basalt flows penetrated by deep core holes in the Pasco Basin or exposed on the surface at certain field section locations

  11. Basaltic rocks analyzed by the Spirit Rover in Gusev Crater

    Science.gov (United States)

    McSween, H. Y.; Arvidson, R. E.; Bell, J. F., III; Blaney, D.; Cabrol, N. A.; Christensen, P. R.; Clark, B. C.; Crisp, J. A.; Crumpler, L. S.; DesMarais, D. J.; Farmer, J. D.; Gellert, R.; Ghosh, A.; Gorevan, S.; Graff, T.; Grant, J.; Haskin, L. A.; Herkenhoff, K. E.; Johnson, J. R.; Jolliff, B. L.; Klingelhoefer, G.; Morris, R. V.; Yen, A.

    2004-01-01

    The Spirit landing site in Gusev Crater on Mars contains dark, fine-grained, vesicular rocks interpreted as lavas. Pancam and Mini-Thermal Emission Spectrometer (Mini-TES) spectra suggest that all of these rocks are similar but have variable coatings and dust mantles. Magnified images of brushed and abraded rock surfaces show alteration rinds and veins. Rock interiors contain Particle X-ray Spectrometer are consistent with picritic basalts, containing normative olivine, pyroxenes, plagioclase, and accessory FeTi oxides. Mossbauer, Pancam, and Mini-TES spectra confirm the presence of olivine, magnetite, and probably pyroxene. These basalts extend the known range of rock compositions composing the martian crust.

  12. On the metamorphic history of an Archaean granitoid greenstone terrane, East Pilbara, Western Australia, using the 40Ar/39Ar age spectrum technique

    International Nuclear Information System (INIS)

    Age spectrum analyses of blue-green hornblendes from amphibolites from the Western Shaw Belt, East Pilbara, Western Australia, indicate an age of at least 3200 Ma for early regional metamorphism. Ages on hornblende and muscovite from the narrow contact zone with the adjacent Yule Batholith probably data updoming of the granitoid gneiss terranes at 2950 Ma. Hornblendes from within the Shaw Batholith and from a contact zone of a post-tectonic granitoid yield ages of 2840-2900 Ma, indicating either prolonged high temperatures within the granitoid gneiss terranes or a separate thermal pulse associated with the intrusion of post-tectonic granitoids. The preservation of very old hornblendes in a narrow greenstone belt surrounded by massive granitoid gneiss domes indicates that remarkable contrasts in metamorphic geotherms existed over short distances during the Late Archaean, suggesting that updoming occurred during a period of rapid tectonism. (orig.)

  13. Isotopic and trace element studies of the origin emplacement and deformation of Archaen mineral deposits in the granite-greenstone terrains of the Kaapvaal Craton

    International Nuclear Information System (INIS)

    The granite-greenstone terrains of the Kaapvaal Craton contain among the oldest metamorphic rocks recognized on Earth and also contain a geographically disproportionately large abundance of mineral concentrations (in particular Au and Sb). However, very little is known about these occurrences a far as the source and age of the rocks in which they occur, the age of the mineralization, the nature and ages of the deformational events affecting the host rocks and the mineralization, the source of the mineralization (in particular Au, Sb and Cu), the mode of concentration of the mineralization, the behaviour of the occurrences in response to metamorphism, why some rocks are mineralized and other compositionally similar rocks are not, and whether or not the occurrences are temporally unique in terms of Earth history, i.e. are they only typical of the Archaean before 3500 Ma ago The objectives of this project were to study these eight aspects

  14. Texture-specific Si isotope variations in Barberton Greenstone Belt cherts record low temperature fractionations in early Archean seawater

    Science.gov (United States)

    Stefurak, Elizabeth J. T.; Fischer, Woodward W.; Lowe, Donald R.

    2015-02-01

    Sedimentary cherts are unusually abundant in early Archean (pre-3.0 Ga) sequences, suggesting a silica cycle that was profoundly different than the modern system. Previously applied for the purpose of paleothermometry, Si isotopes in ancient cherts can offer broader insight into mass fluxes and mechanisms associated with silica concentration, precipitation, diagenesis, and metamorphism. Early Archean cherts contain a rich suite of sedimentological and petrographic textures that document a history of silica deposition, cementation, silicification, and recrystallization. To add a new layer of insight into the chemistry of early cherts, we have used wavelength-dispersive spectroscopy and then secondary ion mass spectrometry (SIMS) to produce elemental and Si and O isotope ratio data from banded black-and-white cherts from the Onverwacht Group of the Barberton Greenstone Belt, South Africa. This geochemical data is then interpreted in the framework of depositional and diagenetic timing of silica precipitation provided by geological observations. SIMS allows the comparison of Si and O isotope ratios of distinct silica phases, including black carbonaceous chert beds and bands (many including well-defined sedimentary grains), white relatively pure chert bands including primary silica granules, early cavity-filling cements, and later quartz-filled veins. Including all chert types and textures analyzed, the δ30Si dataset spans a range from -4.78‰ to +3.74‰, with overall mean 0.20‰, median 0.51‰, and standard deviation 1.30‰ (n = 1087). Most samples have broadly similar δ30Si distributions, but systematic texture-specific δ30Si differences are observed between white chert bands (mean +0.60‰, n = 750), which contain textures that represent primary and earliest diagenetic silica phases, and later cavity-filling cements (mean -1.41‰, n = 198). We observed variations at a ∼100 μm scale indicating a lack of Si isotope homogenization at this scale during

  15. Geochemistry of rare high-nb basalt lavas : are they derived from a mantle wedge metasomatised by slab melts?

    OpenAIRE

    Hastie, Alan R.; Mitchell, Simon F.; Kerr, Andrew C.; Minifie, Matthew J.; Millar, Ian L.

    2011-01-01

    Compositionally, high-Nb basalts are similar to HIMU (high U/Pb) ocean island basalts, continental alkaline basalts and alkaline lavas formed above slab windows. Tertiary alkaline basaltic lavas from eastern Jamaica, West Indies, known as the Halberstadt Volcanic Formation have compositions similar to high-Nb basalts (Nb > 20 ppm). The Halberstadt high-Nb basalts are divided into two compositional sub-groups where Group 1 lavas have more enriched incompatible element concentrations relative t...

  16. Preliminary feasibility study on storage of radioactive wastes in Columbia River basalts. Volume II

    Energy Technology Data Exchange (ETDEWEB)

    ,

    1976-11-01

    Volume II comprises four appendices: analytical data and sample locations for basalt flow type localities; Analytical data and sample locations for measured field sections in Yakima basalts; core hole lithology and analytical data; and geophysical logs. (LK)

  17. Bonding Properties of Basalt Fiber and Strength Reduction According to Fiber Orientation

    OpenAIRE

    Jeong-Il Choi; Bang Yeon Lee

    2015-01-01

    The basalt fiber is a promising reinforcing fiber because it has a relatively higher tensile strength and a density similar to that of a concrete matrix as well as no corrosion possibility. This study investigated experimentally the bonding properties of basalt fiber with cementitious material as well as the effect of fiber orientation on the tensile strength of basalt fiber for evaluating basalt fiber’s suitability as a reinforcing fiber. Single fiber pullout tests were performed and then th...

  18. Age of the youngest Palaeogene flood basalts in East Greenland

    DEFF Research Database (Denmark)

    Heilmann-Clausen, C.; Piasecki, Stefan; Abrahamsen, Niels;

    2008-01-01

    results, this constrains the termination of the East Greenland Paleogene Igneous Province to the Early-Middle Eocene transition (nannoplankton chronozones NP13-NP14/earliest NP15). This is 6-8 Ma younger than according to previous biostratigraphic age assignments. The new data show that flood basalt...

  19. Nuclear waste package materials testing report: basaltic and tuffaceous environments

    International Nuclear Information System (INIS)

    The disposal of high-level nuclear wastes in underground repositories in the continental United States requires the development of a waste package that will contain radionuclides for a time period commensurate with performance criteria, which may be up to 1000 years. This report addresses materials testing in support of a waste package for a basalt (Hanford, Washington) or a tuff (Nevada Test Site) repository. The materials investigated in this testing effort were: sodium and calcium bentonites and mixtures with sand or basalt as a backfill; iron and titanium-based alloys as structural barriers; and borosilicate waste glass PNL 76-68 as a waste form. The testing also incorporated site-specific rock media and ground waters: Reference Umtanum Entablature-1 basalt and reference basalt ground water, Bullfrog tuff and NTS J-13 well water. The results of the testing are discussed in four major categories: Backfill Materials: emphasizing water migration, radionuclide migration, physical property and long-term stability studies. Structural Barriers: emphasizing uniform corrosion, irradiation-corrosion, and environmental-mechanical testing. Waste Form Release Characteristics: emphasizing ground water, sample surface area/solution volume ratio, and gamma radiolysis effects. Component Compatibility: emphasizing solution/rock, glass/rock, glass/structural barrier, and glass/backfill interaction tests. This area also includes sensitivity testing to determine primary parameters to be studied, and the results of systems tests where more than two waste package components were combined during a single test

  20. Friction Joint Between Basalt-Reinforced Composite and Aluminum

    DEFF Research Database (Denmark)

    Costache, Andrei; Glejbøl, Kristian; Sivebæk, Ion Marius;

    2015-01-01

    The purpose of this study was to anchor basalt-reinforced polymers in an aluminum grip using dry friction. Dry friction clamping is considered the optimal solution for post-mounting of load-bearing terminations on composite structures. A new test method is presented for characterizing the...

  1. Assesment of Alkali Resistance of Basalt Used as Concrete Aggregates

    Directory of Open Access Journals (Sweden)

    al-Swaidani Aref M.

    2015-11-01

    Full Text Available The objective of this paper is to report a part of an ongoing research on the influence of using crushed basalt as aggregates on one of durability-related properties of concrete (i.e. alkali-silica reaction which is the most common form of Alkali-Aggregate Reaction. Alkali resistance has been assessed through several methods specified in the American Standards. Results of petrographic examination, chemical test (ASTM C289 and accelerated mortar bar test (ASTM C1260 have particularly been reported. In addition, the weight change and compressive strength of 28 days cured concrete containing basaltic aggregates were also reported after 90 days of exposure to 10% NaOH solution. Dolomite aggregate were used in the latter test for comparison. The experimental results revealed that basaltic rocks quarried from As-Swaida’a region were suitable for production of aggregates for concrete. According to the test results, the studied basalt aggregates can be classified as innocuous with regard to alkali-silica reaction. Further, the 10% sodium hydroxide attack did not affect the compressive strength of concrete.

  2. Basalt nuclear-waste repository remote sensing using electromagnetic techniques

    International Nuclear Information System (INIS)

    The electromagnetic permittivity and attenuation rate of basalt, from the Near Surface Test Facility of the Basalt Waste Isolation Project at Hanford, Washington, have been measured in the laboratory as a function of water content at frequencies from 25 MHz to 1000 MHz. Both the permittivity and the attenuation rate are strongly related to water content of basalt in this frequency range. Completely dehydrated, the rock has a frequency-independent relative permittivity of about 8 and attenuation rates (inverse skin depths) of 0.04 m-1 and 3.2 m-1 at 25 MHz and 1000 MHz, respectively. When completely saturated by tap water to 6% by volume, the relative permittivity ranges from 16.5 to 10.0 and the attenuation ranges from 0.3 m-1 to 5.5 m-1 between 25 MHz and 1000 MHz. The data indicate that high-frequency electromagnetic remote sensing techniques, such as those used in radar, cross-borehole tomography, and borehole logging, may be useful in characterizing proposed basalt repositories and monitoring established waste repositories. Electromagnetic methods are particularly suited to delineating water content of the rock and, when completely saturated, crack and pore porosity of the rock mass within a repository. 7 references, 3 figures

  3. Basalt Waste Isolation Project. Annual report, fiscal year 1979

    Energy Technology Data Exchange (ETDEWEB)

    1979-11-01

    This project is aimed at examining the feasibility and providing the technology to design and construct a radwaste repository in basalt formations beneath and within the Hanford Site. The project is divided into seven areas: systems integration, geosciences, hydrologic studies, engineered barriers, near-surface test facility, engineering testing, and repository engineering. This annual report summarizes key investigations in these seven areas. (DLC)

  4. Basalt Waste Isolation Project. Annual report, fiscal year 1979

    International Nuclear Information System (INIS)

    This project is aimed at examining the feasibility and providing the technology to design and construct a radwaste repository in basalt formations beneath and within the Hanford Site. The project is divided into seven areas: systems integration, geosciences, hydrologic studies, engineered barriers, near-surface test facility, engineering testing, and repository engineering. This annual report summarizes key investigations in these seven areas

  5. Assesment of Alkali Resistance of Basalt Used as Concrete Aggregates

    Science.gov (United States)

    al-Swaidani, Aref M.; Baddoura, Mohammad K.; Aliyan, Samira D.; Choeb, Walid

    2015-11-01

    The objective of this paper is to report a part of an ongoing research on the influence of using crushed basalt as aggregates on one of durability-related properties of concrete (i.e. alkali-silica reaction which is the most common form of Alkali-Aggregate Reaction). Alkali resistance has been assessed through several methods specified in the American Standards. Results of petrographic examination, chemical test (ASTM C289) and accelerated mortar bar test (ASTM C1260) have particularly been reported. In addition, the weight change and compressive strength of 28 days cured concrete containing basaltic aggregates were also reported after 90 days of exposure to 10% NaOH solution. Dolomite aggregate were used in the latter test for comparison. The experimental results revealed that basaltic rocks quarried from As-Swaida'a region were suitable for production of aggregates for concrete. According to the test results, the studied basalt aggregates can be classified as innocuous with regard to alkali-silica reaction. Further, the 10% sodium hydroxide attack did not affect the compressive strength of concrete.

  6. Depleted basaltic lavas from the proto-Iceland plume, Central East Greenland

    DEFF Research Database (Denmark)

    Waight, Tod Earle; Baker, Joel A.

    2012-01-01

    New geochemical and isotopic data are presented for volumetrically minor, depleted low-Ti basalts that occur in the Plateau Basalt succession of central East Greenland (CEG), formed during the initial stages of opening of the North Atlantic at 55 Ma. The basalts have MORB-like geochemistry (e.g. ...

  7. Assessing microstructures of pyrrhotites in basalts by multifractal analysis

    Directory of Open Access Journals (Sweden)

    S. Xie

    2010-07-01

    Full Text Available Understanding and describing spatial arrangements of mineral particles and determining the mineral distribution structure are important to model the rock-forming process. Geometric properties of individual mineral particles can be estimated from thin sections, and different models have been proposed to quantify the spatial complexity of mineral arrangement. The Gejiu tin-polymetallic ore-forming district, located in Yunnan province, southwestern China, is chosen as the study area. The aim of this paper is to apply fractal and multifractal analysis to quantify distribution patterns of pyrrhotite particles from twenty-eight binary images obtained from seven basalt segments and then to discern the possible petrological formation environments of the basalts based on concentrations of trace elements. The areas and perimeters of pyrrhotite particles were measured for each image. Perimeter-area fractal analysis shows that the perimeter and area of pyrrhotite particles follow a power-law relationship, which implies the scale-invariance of the shapes of the pyrrhotites. Furthermore, the spatial variation of the pyrrhotite particles in space was characterized by multifractal analysis using the method of moments. The results show that the average values of the area-perimeter exponent (DAP, the width of the multifractal spectra (Δ(D(0−D(2 and Δ(D(qminD(qmax and the multifractality index (τ"(1 for the pyrrhotite particles reach their minimum in the second basalt segment, which implies that the spatial arrangement of pyrrhotite particles in Segment 2 is less heterogeneous. Geochemical trace element analysis results distinguish the second basalt segment sample from other basalt samples. In this aspect, the fractal and multifractal analysis may provide new insights into the quantitative assessment of mineral microstructures which may be closely associated with the petrogenesis as shown by the

  8. The identification of basalt flow features from borehole television logs

    International Nuclear Information System (INIS)

    This study investigated whether basalt features found in outcrops and cores could be identified in open borehole walls by the use of the borehole television camera. To answer this question detailed outcrop surveys were carried out in several locations in the Snake River Plain, Idaho. A similar type of survey was also done on several locations in the Snake River Plain, Idaho. A similar type of survey was also done on several cores from the Idaho National Engineering Laboratory, southeast Idaho. Borehole television logs were viewed to find similar basalt features that were noted in cores and outcrops. From these studies it was found that basalt features can be identified in open borehole walls by the borehole television camera. The basalt flows can be divided into four zones: an upper vesicular zone; a columnar zone; a central zone; and a lower vesicular zone. The upper vesicular zone can be further subdivided into four subzones: an upper vesicular subzone; a transitional subzone; a lower vesicular subzone; and a bubble train subzone. Some specific features found in the borehole TV logs were: bubble-trains, vesicle plumes, borehole extensions, and pipe vesicles. The overall distinctions for the zones were based on the vesicularity. An overall pattern of vesicles was found to be a progression of small numerous vesicles at the top of a flow which increase in size, but decrease in number, towards the center of the flow. The opposite is true starting at the bottom of the basalt flow where small vesicles are numerous, but increase in size while decreasing in number towards the center part of the flow. 14 refs., 3 figs

  9. Geochemistry of Two Types of Basalts in the Emeishan Basaltic Province: Evidence for Mantle Plume-Lithosphere Interaction

    Institute of Scientific and Technical Information of China (English)

    张招崇; 王福生

    2002-01-01

    Based on the temporal-spatial distribution and geochemical characteristics, the Emeishan basalts can be divided into two types: high-P2O-TiO2 basalt (HPT) and low-P2O5-TiO2 basalt (LPT), which differ distinctly in geochemistry: the LPTs are characterized by relatively high abundances of MgO, total FeO and P2O5 and compatible elements (Cr, Ni, Sc), and relatively low contents of moderately compatible elements (V, Y, Yb, Co), LREE and other incompatible elements compared with the HPT. On the diagrams of trace element ratios, they are plotted on an approximately linear mixing line between depleted and enriched mantle sources, suggesting that these two types of basalts resulted from interactions of varying degrees between mantle plume and lithospheric mantle containing such volatile-rich minerals as amphibole and apatite. The source region of the LPT involves a smaller proportion of lithospheric components, while that of the HTP has a larger proportion of lithospheric components. Trachyte is generated by partial melting of the basic igneous rocks at the base of the lower continental crust. Both the two types of magmas underwent certain crystal fractionation and contamination of the lower crust at high-level magma chambers and en route to the surface.

  10. Rare earth chemistry of gold-bearing sedimentary carbonate horizons from the Abitibi Greenstone Belt, Ontario, Canada

    International Nuclear Information System (INIS)

    The ankerite, gold ore bodies of the Dome Mine, Timmins, Ontario are interflow units, 1 to 3 m thick in a sequence of tholeiitic basalts. The units consist of discontinuous layers of ferroan dolomite, chert and pyroclastic material, and laminations of iron sulfides, tourmaline, and graphite. They have been interpreted as sediments on the basis of their internal structure. Seven Rare Earth elements (REE) (Ce, Nd, Sm, Eu, Gd, Tb, Tm, Yb) were determined by instrumental neutron activation analysis, on 10 samples of carbonate material from the ankerite units. The chondrite normalized REE plots have relatively flat patterns with, in some cases, positive Europium anomalies. The flat patterns suggest that the fluids from which the carbonate precipitated was in equilibrium with volcanic rocks of tholeiitic and komatiitic composition. The positive Europium anomalies imply that the fluids were reducing at times. Such patterns are characteristic of Archaean sediments and also the precipitates associated with the discharge of hydrothermal solutions from vents on the East Pacific Rise

  11. Investigation on mechanical properties of basalt composite fabrics (experiment study)

    Science.gov (United States)

    Talebi Mazraehshahi, H.; Zamani, H.

    2010-06-01

    To fully appreciate the role and application of composite materials to structures, correct understanding of mechanical behaviors required for selection of optimum material. Fabric reinforced composites are composed of a matrix that is reinforced with pliable fabric, glass fabric is most popular reinforcement for different application specially in aircraft structure, although other fabric material are also used. At this study new fabric material called basalt with epoxy resin introduced and mechanical behaviors of this material investigated from view point of testing. For this study two type of fabric with different thickness used. Comparison between this composite reinforcement with popular reinforcement as carbon, glass, kevlar performed. To determine mechanical properties of epoxy based basalt fabric following test procedure performed : 1). Tensile testing according to ASTM D3039 in 0° and 90° direction to find ultimate strength in tension and shear, modulus of elasticity, elangation and ultimate strain. 2). Compression testing according to EN 2850 ultimate compression strength and maximum deformation under compression loading. 3). Shear testing according to ASTM D3518-94 to find in plane shear response of polymer matrix composites materials. 4). Predict flexural properties of sandwich construction which manufactured from basalt facing with PVC foam core according to ASTM C393-94. Material strength properties must be based on enough tests of material to meet the test procedure specifications [1]. For this reason six specimens were manufactured for testing and the tests were performed on them using an INSTRON machine model 5582. In the study, the effect of percent of resin in basalt reinforced composite was investigated. Also the weights of the ballast based composites with different percent of resin were measured with conventional composites. As the weight is an important parameter in aerospace industry when the designer wants to replace one material with

  12. Investigation on mechanical properties of basalt composite fabrics (experiment study

    Directory of Open Access Journals (Sweden)

    Talebi Mazraehshahi H.

    2010-06-01

    Full Text Available To fully appreciate the role and application of composite materials to structures, correct understanding of mechanical behaviors required for selection of optimum material. Fabric reinforced composites are composed of a matrix that is reinforced with pliable fabric, glass fabric is most popular reinforcement for different application specially in aircraft structure, although other fabric material are also used. At this study new fabric material called basalt with epoxy resin introduced and mechanical behaviors of this material investigated from view point of testing. For this study two type of fabric with different thickness used. Comparison between this composite reinforcement with popular reinforcement as carbon, glass, kevlar performed. To determine mechanical properties of epoxy based basalt fabric following test procedure performed : 1. Tensile testing according to ASTM D3039 in 0° and 90° direction to find ultimate strength in tension and shear, modulus of elasticity, elangation and ultimate strain. 2. Compression testing according to EN 2850 ultimate compression strength and maximum deformation under compression loading. 3. Shear testing according to ASTM D3518-94 to find in plane shear response of polymer matrix composites materials. 4. Predict flexural properties of sandwich construction which manufactured from basalt facing with PVC foam core according to ASTM C393-94. Material strength properties must be based on enough tests of material to meet the test procedure specifications [1]. For this reason six specimens were manufactured for testing and the tests were performed on them using an INSTRON machine model 5582. In the study, the effect of percent of resin in basalt reinforced composite was investigated. Also the weights of the ballast based composites with different percent of resin were measured with conventional composites. As the weight is an important parameter in aerospace industry when the designer wants to replace one

  13. Surface modification of basalt with silane coupling agent on asphalt mixture moisture damage

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • A new silane coupling agent was synthesized based on KH570. • Basalt surface was modified using the new silane coupling agent. • Chemical bond between basalt and the new silane coupling agent was formed. • Asphalt mixture which used modified basalt show superior water stability. - Abstract: A new silane coupling agent was synthesized based on γ-(methacryloyloxy) propyltrimethoxysilane (KH570). The surface of basalt rocks was modified by KH570 and the new silane coupling agent (NSCA), and the interfacial interaction between silane coupling agent and basalt was also studied. Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis showed that the silane coupling agent molecule bound strongly with basalt rocks. Scanning electronic microscopy (SEM) observation showed that a thin layer of coupling agent was formed on the surface of modified basalt. The boiling test and immersion Marshall test confirmed that the moisture sensitivity of basalt modified with the new silane coupling agent increased more significantly than that untreated and treated with KH570. The Retained Marshall Strength of basalt modified with the new coupling agent increased from 71.74% to 87.79% compared with untreated basalt. The results indicated that the new silane coupling agent played an important role in improving the interfacial performance between basalt and asphalt

  14. Surface modification of basalt with silane coupling agent on asphalt mixture moisture damage

    Energy Technology Data Exchange (ETDEWEB)

    Min, Yahong; Fang, Ying; Huang, Xiaojun; Zhu, Yinhui; Li, Wensheng [College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 (China); Yuan, Jianmin [College of Materials Engineering, Hunan University, Changsha, 410082 (China); Tan, Ligang [College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082 (China); Wang, Shuangyin [State Key Laboratory of Chem/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 (China); Wu, Zhenjun, E-mail: wooawt@163.com [College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 (China)

    2015-08-15

    Graphical abstract: - Highlights: • A new silane coupling agent was synthesized based on KH570. • Basalt surface was modified using the new silane coupling agent. • Chemical bond between basalt and the new silane coupling agent was formed. • Asphalt mixture which used modified basalt show superior water stability. - Abstract: A new silane coupling agent was synthesized based on γ-(methacryloyloxy) propyltrimethoxysilane (KH570). The surface of basalt rocks was modified by KH570 and the new silane coupling agent (NSCA), and the interfacial interaction between silane coupling agent and basalt was also studied. Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis showed that the silane coupling agent molecule bound strongly with basalt rocks. Scanning electronic microscopy (SEM) observation showed that a thin layer of coupling agent was formed on the surface of modified basalt. The boiling test and immersion Marshall test confirmed that the moisture sensitivity of basalt modified with the new silane coupling agent increased more significantly than that untreated and treated with KH570. The Retained Marshall Strength of basalt modified with the new coupling agent increased from 71.74% to 87.79% compared with untreated basalt. The results indicated that the new silane coupling agent played an important role in improving the interfacial performance between basalt and asphalt.

  15. Basalt characterization by means of nuclear and electrical well logging techniques. Case study from Southern Syria

    International Nuclear Information System (INIS)

    Nuclear well logging, including natural gamma ray, density, and neutron-porosity techniques are used with electrical well logging of long and short normal techniques to characterize the basaltic areas largely extended in Southern Syria. Statistical analysis approach with the threshold concept has been adapted for such characterization, where four kinds of basalt have been identified: very hard basalt, hard basalt, fractured basalt, and basalt alteration products. The spectrometric gamma technique has also been applied on the retrieved rock samples in order to determine the radioactive content (eU, eTh, and K%) of the basaltic section in the study area. No radioactive anomalies have been detected, the radioactive values are normal and in the expected range.

  16. Lunar ferroan anorthosites and mare basalt sources - The mixed connection

    Science.gov (United States)

    Ryder, Graham

    1991-11-01

    Global overturn of a hot, gravitationally unstable lunar mantle immediately following the solidification of a magma ocean explains several characteristics of lunar petrology. Lunar mare basalt sources are inferred to be depleted in europium and alumina. These depletions are consensually attributed to complementary plagioclase floating from a magma ocean. However, in contrast to the mare basalt source parent magma, the ferroan anorthosite parent magma was more evolved by virtue of its lower Mg/Fe ratio and Ni abundances, although less evolved in its poverty of clinopyroxene constituents, flat rare earth pattern, and lower incompatible element abundances. The europium anomaly in mare sources is inferred to be present at 400 km depth, too deep to have been directly influenced by plagioclase crystallization. Massive overturning of the post-magma ocean mantle would have carried down clinopyroxene, ilmenite, and phases containing fractionated rare earths, europium anomalies, and some heat-producing radionuclides.

  17. Flood basalt volcanism during the past 250 million years

    Science.gov (United States)

    Rampino, Michael R.; Stothers, Richard B.

    1988-01-01

    A chronology of the initiation dates of major continental flood basalt volcanism is established from published potassium-argon (K-Ar) and argon-argon (Ar-Ar) ages of basaltic rocks and related basic intrusions. The dating is therefore independent of the biostratigraphic and paleomagnetic time scales. Estimated errors of the initiation dates of the volcanic episodes determined from the distributions of the radiometric ages are, approximately, + or - 4 percent. There were 11 distinct episodes during the past 250 million years. Sometimes appearing in pairs, the episodes have occurred quasi-periodically with a mean cycle time of 32 + or - 1 (estimated error of the mean) million years. The initiation dates of the episodes are close to the estimated dates of mass extinctions of marine organisms. Showers of impacting comets may be the cause.

  18. Mars weathering analogs - Secondary mineralization in Antarctic basalts

    Science.gov (United States)

    Berkley, J. L.

    1982-01-01

    Alkalic basalt samples from Ross Island, Antarctica, are evaluated as terrestrial analogs to weathered surface materials on Mars. Secondary alteration in the rocks is limited to pneumatolytic oxidation of igneous minerals and glass, rare groundmass clay and zeolite mineralization, and hydrothermal minerals coating fractures and vesicle surfaces. Hydrothermal mineral assemblages consist mainly of K-feldspar, zeolites (phillipsite and chabazite), calcite, and anhydrite. Low alteration rates are attributed to cold and dry environmental factors common to both Antarctica and Mars. It is noted that mechanical weathering (aeolian abrasion) of Martian equivalents to present Antarctic basalts would yield minor hydrothermal minerals and local surface fines composed of primary igneous minerals and glass but would produce few hydrous products, such as palagonite, clay or micas. It is thought that leaching of hydrothermal vein minerals by migrating fluids and redeposition in duricrust deposits may represent an alternate process for incorporating secondary minerals of volcanic origin into Martian surface fines.

  19. Petrogeochemistry of Mesozoic basaltic volcanics in Daqingshan area

    International Nuclear Information System (INIS)

    Through the discussion on petrogeochemistry of Later Mesozoic basaltic volcanics in Daqingshan Basin in Manzhouli area, combined with field observation and the predecessors' study, its magma evolution,genesis and diagenetic structural environment are discussed, and some suggestion are provided for the further work. Basaltic magma in this area is believed to be derived from mantle with incompatible elements which were later participated by some crustal materials. It is a partially melting product of mantle by early metasomatized fluid under lithosphere extension. Through petrogeochemical analysis of the volcanics and the contrast to the adjacent uranium-producing volcanics, it is concluded that this region has structural environment to form magma evolution series which are more favorable for volcanic hydrothermal-type uranium and polymetallic mineralization. (authors)

  20. Environmental resistance and mechanical performance of basalt and glass fibers

    International Nuclear Information System (INIS)

    The treated basalt and glass fibers with sodium hydroxide and hydrochloric acid solutions for different times were analyzed, respectively. This paper summarized the mass loss ratio and the strength maintenance ratios of the fibers after treatment. The fibers' surface corrosion morphologies were characterized using scanning electron microscopy and their compositions were detected using energy dispersive X-ray spectroscopy. The acid resistance was much better than the alkali resistance for the basalt fibers. Nevertheless, for the glass fibers the situation is different: the acid resistance was almost the same as the alkali resistance. Among the two types of aqueous environments evaluated, the alkali solution is the most aggressive to the fibers' surface. The possible corrosion mechanisms are revealed.

  1. A new basaltic glass microanalytical reference material for multiple techniques

    Science.gov (United States)

    Wilson, Steve; Koenig, Alan; Lowers, Heather

    2012-01-01

    The U.S. Geological Survey (USGS) has been producing reference materials since the 1950s. Over 50 materials have been developed to cover bulk rock, sediment, and soils for the geological community. These materials are used globally in geochemistry, environmental, and analytical laboratories that perform bulk chemistry and/or microanalysis for instrument calibration and quality assurance testing. To answer the growing demand for higher spatial resolution and sensitivity, there is a need to create a new generation of microanalytical reference materials suitable for a variety of techniques, such as scanning electron microscopy/X-ray spectrometry (SEM/EDS), electron probe microanalysis (EPMA), laser ablation inductively coupled mass spectrometry (LA-ICP-MS), and secondary ion mass spectrometry (SIMS). As such, the microanalytical reference material (MRM) needs to be stable under the beam, be homogeneous at scales of better than 10–25 micrometers for the major to ultra-trace element level, and contain all of the analytes (elements or isotopes) of interest. Previous development of basaltic glasses intended for LA-ICP-MS has resulted in a synthetic basaltic matrix series of glasses (USGS GS-series) and a natural basalt series of glasses (BCR-1G, BHVO-2G, and NKT-1G). These materials have been useful for the LA-ICP-MS community but were not originally intended for use by the electron or ion beam community. A material developed from start to finish with intended use in multiple microanalytical instruments would be useful for inter-laboratory and inter-instrument platform comparisons. This article summarizes the experiments undertaken to produce a basalt glass reference material suitable for distribution as a multiple-technique round robin material. The goal of the analytical work presented here is to demonstrate that the elemental homogeneity of the new glass is acceptable for its use as a reference material. Because the round robin exercise is still underway, only

  2. Structural Analysis of Basalt Fiber Reinforced Plastic Wind Turbine Blade

    OpenAIRE

    Mengal Ali Nawaz; Karuppanan Saravanan; Wahab Azmi Abdul

    2014-01-01

    In this study, Basalt fiber reinforced plastic (BFRP) wind turbine blade was analyzed and compared with Glass fiber reinforced plastic blade (GFRP). Finite element analysis (FEA) of blade was carried out using ANSYS. Data for FEA was obtained by using rule of mixture. The shell element in ANSYS was used to simulate the wind turbine blade and to conduct its strength analysis. The structural analysis and comparison of blade deformations proved that BFRP wind turbine blade has better strength co...

  3. Investigation on mechanical properties of basalt composite fabrics (experiment study)

    OpenAIRE

    Talebi Mazraehshahi H.; Zamani H.

    2010-01-01

    To fully appreciate the role and application of composite materials to structures, correct understanding of mechanical behaviors required for selection of optimum material. Fabric reinforced composites are composed of a matrix that is reinforced with pliable fabric, glass fabric is most popular reinforcement for different application specially in aircraft structure, although other fabric material are also used. At this study new fabric material called basalt with epoxy resin introduced ...

  4. Numerical simulation of wear of basalt lava spinning rolls

    OpenAIRE

    A. Lisiecki; A. Klimpel; D. Janicki

    2006-01-01

    Purpose: of this paper: Results of the study of wear phenomena of cascade spinning rolls during stone woolproduction process are described.Design/methodology/approach: The study was based on direct process observations, chemical analysis andtemperature measurements of basalt lava, metallographic examinations of the spinning rolls deposits. It was showedthat the deposits of spinning rolls are worn in very different way, depending on the roll position in rolls cascade.Findings: Predominant wear...

  5. Interim reclamation report, Basalt Waste Isolation project: Boreholes, 1989

    International Nuclear Information System (INIS)

    In 1968, a program was started to assess the feasibility of storing Hanford Site defense waste in deep caverns constructed in basalt. This program was expanded in 1976 to include investigations of the Hanford Site as a potential location for a mined commercial nuclear waste repository. An extensive site characterization program was begun to determine the feasibility of using the basalts beneath the Hanford Site for the repository. Site research focused primarily on determining the direction and speed of groundwater movement, the uniformity of basalt layers, and tectonic stability. Some 98 boreholes were sited, drilled, deepened, or modified by BWIP between 1977 and 1988 to test the geologic properties of the Site. On December 22, 1987, President Reagan signed into law the Nuclear Waste Policy Amendments Act of 1987, which effectively stopped all repository-related activities except reclamation of disturbed lands at the Hanford Site. This report describes the development of the reclamation program for the BWIP boreholes, its implementation, and preliminary estimates of its success. The goal of the reclamation program is to return sites disturbed by the repository program as nearly as practicable to their original conditions using native plant species. 48 refs., 28 figs., 14 tabs

  6. The consanguinity of the oldest Apollo 11 mare basalts

    Science.gov (United States)

    Gamble, R. P.; Coish, R. A.; Taylor, L. A.

    1978-01-01

    The textural, mineralogical, and chemical relationships between three of the oldest dates lunar mare basalt samples returned by Apollo 11 (10003, 10029 and 10062) were investigated. Very strong resemblances were noted between the modal minerologies of 10003 and 10029. Significantly more modal olivine and cristobalite was observed in 10062 than in the other basalt samples. A detailed examination of mineral-chemical relationships among the samples revealed similarities between 10003 and 10062 and differences between these two rocks and 10029, the most significant of which is the presence of akaganeite in 10029, implying that lawrencite was present in the pristine sample of 10029 but not in 10003 and 10062. Results of a Wright-Doherty mixing program used to test various fractional crystallization schemes show that 10062 can be derived from a liquid with the composition of either 10003 or 10029 by removing 2-5% ilmenite and 5% olivine. By removing about 6% plagioclase, 10003 can be derived from a liquid with the bulk composition of 10062. It is concluded that 10003 and 10029 may have come from different basaltic flows, whereas it is possible that 10003 and 10062 were derived from the same parental magma by near-surface fractionation of olivine plus ilmenite or of plagioclase plus or minus olivine.

  7. Basalt Waste Isolation Project. Annual report, fiscal year 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-11-01

    During this fiscal year the information available in the fields of geology and hydrology of the Columbia Plateau was consolidated and two reports were issued summarizing this information. In addition, the information on engineered barriers was consolidated and a report summarizing the research to date on waste package development and design of borehole seals was prepared. The waste package studies, when combined with the hydrologic integration, revealed that even under extreme disruptive conditions, a repository in basalt with appropriately designed waste packages can serve as an excellent barrier for containment of radionuclides for the long periods of time required for waste isolation. On July 1, 1980, the first two heater tests at the Near-Surface Test Facility were started and have been successfully operated to this date. The papers on the Near-Surface Test Facility section of this report present the results of the equipment installed and the preliminary results of the testing. In October 1979, the US Department of Energy selected the joint venture of Kaiser Engineers/Parsons Brinckerhoff Quade and Douglas, Inc., to be the architect-engineer to produce a conceptual design of a repository in basalt. During the year, this design has progressed and concept selection has now been completed. This annual report presents a summary of the highlights of the work completed during fiscal year 1980. It is intended to supplement and summarize the nearly 200 papers and reports that have been distributed to date as a part of the Basalt Waste Isolation Project studies.

  8. Interim reclamation report, Basalt Waste Isolation project: Boreholes, 1989

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, C.A.; Rickard, W.H. Jr.; Hefty, M.G.

    1990-03-01

    In 1968, a program was started to assess the feasibility of storing Hanford Site defense waste in deep caverns constructed in basalt. This program was expanded in 1976 to include investigations of the Hanford Site as a potential location for a mined commercial nuclear waste repository. An extensive site characterization program was begun to determine the feasibility of using the basalts beneath the Hanford Site for the repository. Site research focused primarily on determining the direction and speed of groundwater movement, the uniformity of basalt layers, and tectonic stability. Some 98 boreholes were sited, drilled, deepened, or modified by BWIP between 1977 and 1988 to test the geologic properties of the Site. On December 22, 1987, President Reagan signed into law the Nuclear Waste Policy Amendments Act of 1987, which effectively stopped all repository-related activities except reclamation of disturbed lands at the Hanford Site. This report describes the development of the reclamation program for the BWIP boreholes, its implementation, and preliminary estimates of its success. The goal of the reclamation program is to return sites disturbed by the repository program as nearly as practicable to their original conditions using native plant species. 48 refs., 28 figs., 14 tabs.

  9. Basalt Waste Isolation Project. Annual report, fiscal year 1980

    International Nuclear Information System (INIS)

    During this fiscal year the information available in the fields of geology and hydrology of the Columbia Plateau was consolidated and two reports were issued summarizing this information. In addition, the information on engineered barriers was consolidated and a report summarizing the research to date on waste package development and design of borehole seals was prepared. The waste package studies, when combined with the hydrologic integration, revealed that even under extreme disruptive conditions, a repository in basalt with appropriately designed waste packages can serve as an excellent barrier for containment of radionuclides for the long periods of time required for waste isolation. On July 1, 1980, the first two heater tests at the Near-Surface Test Facility were started and have been successfully operated to this date. The papers on the Near-Surface Test Facility section of this report present the results of the equipment installed and the preliminary results of the testing. In October 1979, the US Department of Energy selected the joint venture of Kaiser Engineers/Parsons Brinckerhoff Quade and Douglas, Inc., to be the architect-engineer to produce a conceptual design of a repository in basalt. During the year, this design has progressed and concept selection has now been completed. This annual report presents a summary of the highlights of the work completed during fiscal year 1980. It is intended to supplement and summarize the nearly 200 papers and reports that have been distributed to date as a part of the Basalt Waste Isolation Project studies

  10. High water content in primitive continental flood basalts.

    Science.gov (United States)

    Xia, Qun-Ke; Bi, Yao; Li, Pei; Tian, Wei; Wei, Xun; Chen, Han-Lin

    2016-01-01

    As the main constituent of large igneous provinces, the generation of continental flood basalts (CFB) that are characterized by huge eruption volume (>10(5) km(3)) within short time span (factors are not mutually exclusive. There are growing evidences for high temperature, decompression and mafic source rocks, albeit with hot debate. However, there is currently no convincing evidence of high water content in the source of CFB. We retrieved the initial H2O content of the primitive CFB in the early Permian Tarim large igneous province (NW China), using the H2O content of ten early-formed clinopyroxene (cpx) crystals that recorded the composition of the primitive Tarim basaltic melts and the partition coefficient of H2O between cpx and basaltic melt. The arc-like H2O content (4.82 ± 1.00 wt.%) provides the first clear evidence that H2O plays an important role in the generation of CFB. PMID:27143196

  11. Compositional Grading in an Impact-produced Spherule Bed, Barberton Greenstone Belt, South Africa: A Key to Condensation History of Rock Vapor Clouds

    Science.gov (United States)

    Krull, A. E.; Lowe, D. R.; Byerly, G. R.

    2003-01-01

    The chemical and physical processes by which spherules form during the condensation of impact-produced rock vapor clouds are poorly understood. Although efforts have been made to model the processes of spherule formation, there is presently a paucity of field data to constrain the resulting theoretical models. The present study examines the vertical compositional variability in a single early Archean spherule bed in the Barberton Greenstone Belt (BGB), South Africa, in order to better identify the process by which impact vapor clouds condense and spherules form and accumulate. The BGB spherule beds are suitable for this type of study because of their great thickness, often exceeding 25cm of pure spherules, due to the massive sizes of the impactors. Two main problems complicate analysis of vertical compositional variability of graded spherule beds: (1) differential settling of particles in both the vapor and water column due to density and size differences and (2) turbulence within the vapor cloud. The present study compares sections of spherule bed S3 from four different depositional environments in the Barberton Greenstone Belt: (1) The Sheba Mine section (SAF-381) was deposited under fairly low energy conditions in deep water, providing a nice fallout sequence, and also has abundant Ni-rich spinels; (2) Jay's Chert section (SAF-380) was deposited in subaerial to shallow-water conditions with extensive post-depositional reworking by currents. The spherules also have preserved spinels; (3) the Loop Road section (loc. SAF-295; samp. KSA-7) was moderately reworked and has only rare preservation of spinels; and (4) the shallow-water Barite Syncline section (loc. SAF-206; samp KSA-1) has few to no spinels preserved and is not reworked. Although all of the spherule beds have been altered by silica diagenesis and K-metasomatism, most of the compositional differences between these sections appear to reflect their diagenetic histories, possibly related to their differing

  12. Rochas ultramáficas plutônicas do greenstone belt Rio das Velhas na porção central do Quadrilátero Ferrífero, Minas Gerais, Brasil Plutonic ultramafic rocks of the greenstone belt Rio das Velhas in the central portion of the Quadrilátero Ferrífero, State of Minas Gerais, Brazil

    OpenAIRE

    Gabriela Magalhães da Fonseca; Hanna Jordt Evangelista

    2013-01-01

    Em Amarantina, distrito de Ouro Preto, encontram-se rochas ultramáficas expostas em duas áreas com cerca de 500 m² cada. As rochas afloram no Complexo do Bação, que é o embasamento gnáissico do greenstone belt Rio das Velhas, na porção central do Quadrilátero Ferrífero (QF). O interesse no estudo petrogenético desses corpos deve-se à preservação parcial de minerais ígneos, ausentes na maior parte das rochas ultramáficas totalmente metamorfizadas do QF. Entre essas rochas, destacam-se os estea...

  13. Rochas ultramáficas plutônicas do greenstone belt Rio das Velhas na porção central do Quadrilátero Ferrífero, Minas Gerais, Brasil Plutonic ultramafic rocks of the greenstone belt Rio das Velhas in the central portion of the Quadrilátero Ferrífero, State of Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Gabriela Magalhães da Fonseca

    2013-03-01

    Full Text Available Em Amarantina, distrito de Ouro Preto, encontram-se rochas ultramáficas expostas em duas áreas com cerca de 500 m² cada. As rochas afloram no Complexo do Bação, que é o embasamento gnáissico do greenstone belt Rio das Velhas, na porção central do Quadrilátero Ferrífero (QF. O interesse no estudo petrogenético desses corpos deve-se à preservação parcial de minerais ígneos, ausentes na maior parte das rochas ultramáficas totalmente metamorfizadas do QF. Entre essas rochas, destacam-se os esteatitos e os serpentinitos, devido a sua importância econômica. As rochas ultramáficas de Amarantina possuem textura equigranular, fato que as caracteriza como tendo origem plutônica, isto é, trata-se de metaperidotitos. Possuem grãos maiores de olivina, piroxênio e espinélio da rocha ígnea original distribuídos em matriz metamórfica fina com talco, serpentinas, cloritas, anfibólios e minerais opacos. Escassas arita (NiSbAs e breithauptita (NiSb foram formadas a partir de pentlandita durante o metamorfismo associado a hidrotermalismo. A comparação da composição química com a de um metakomatiito com textura spinifex do QF, bem como com rochas komatitiiticas de outras partes do mundo, mostra que os metaperidotitos são, quimicamente, semelhantes aos komatiitos não-desfalcados em alumínio. Portanto é provável que as rochas ultramáficas estudadas correspondam à porção plutônica do magmatismo komatitiitico do Grupo Nova Lima, que é a unidade basal do greenstone belt Rio das Velhas.In Amarantina, district of Ouro Preto (State of Minas Gerais, Brazil, ultramafic rock exposures are found along two areas of about 500 m² each. The rocks crop out in the Bação complex, which is the gneissic basement of the Rio das Velhas greenstone belt in the central portion of the Quadrilátero Ferrífero (QF. The interest in a petrogenetic study of the ultramafic rocks is the partial preservation of igneous minerals, which are not observed

  14. Inclusões fluidas crepitadas, fluidos hipersalinos e aquo-carbônicos em quartzo associado a rochas micáceas no Granito Xinguara - Terreno Granito-Greenstone de Rio Maria, PA Decrepitated fluid inclusions, aqueous-carbonic and hypersaline fluids in quartz associated to micaceous rocks in the Xinguara Granite - Rio Maria Granite - Greenstone terrain, Pará, Brazil

    Directory of Open Access Journals (Sweden)

    Marcelo Leopoldo Weber

    2008-03-01

    Full Text Available As rochas micáceas encontradas no Granito Xinguara, terreno Granito-Greenstone de Rio Maria, Pará, são compostas por muscovita e clorita com níveis de quartzo intercalados, que formam uma xistosidade bem desenvolvida. Essa xistosidade é cortada por veios de quartzo. Ambas as gerações de quartzo apresentam os mesmos tipos de inclusões fluidas em halos ou trilhas secundárias de composições variadas entre aquosas, aquo-carbônicas e saturadas em torno de grandes inclusões primárias crepitadas ou em trilhas transgranulares secundárias. A grande variação de temperaturas de homogeneização, a alta salinidade, as evidências de estrangulamento e a existência das inclusões crepitadas permitem supor forte influência de alterações pós-formacionais e reequilíbrio relacionados à intrusão do granito. Essas rochas foliadas são, portanto, enclaves metassedimentares afetados por fluidos graníticos hipersalinos aquo-carbônicos.The micaceous rocks occurring in the Xinguara Granite, Rio Maria Granite-Greenstone terrain, Pará State, Brazil, are composed of muscovite and chlorite with quartz levels intercalated forming a well developed schistosity. This schistosity is cut by quartz veins. Both quartz generations show the same aqueous, aqueous-carbonic and halite-bearing fluid inclusions either in secondary inclusions halos and trails surrounding decrepitated primary fluid inclusions or in transgranular secondary trails. A wide variation of homogenization temperatures, high salinity, necking down and the decrepitated inclusions existence indicates strong influence of post-formational alteration and reequilibration linked to the granite intrusion. These foliated rocks are metasedimentary enclaves affected by late hypersaline aqueous-carbonic granitic fluids.

  15. Lunar Mare Basalts as Analogues for Martian Volcanic Compositions: Evidence from Visible, Near-IR, and Thermal Emission Spectroscopy

    Science.gov (United States)

    Graff, T. G.; Morris, R. V.; Christensen, P. R.

    2003-01-01

    The lunar mare basalts potentially provide a unique sample suite for understanding the nature of basalts on the martian surface. Our current knowledge of the mineralogical and chemical composition of the basaltic material on Mars comes from studies of the basaltic martian meteorites and from orbital and surface remote sensing observations. Petrographic observations of basaltic martian meteorites (e.g., Shergotty, Zagami, and EETA79001) show that the dominant phases are pyroxene (primarily pigeonite and augite), maskelynite (a diaplectic glass formed from plagioclase by shock), and olivine [1,2]. Pigeonite, a low calcium pyroxene, is generally not found in abundance in terrestrial basalts, but does often occur on the Moon [3]. Lunar samples thus provide a means to examine a variety of pigeonite-rich basalts that also have bulk elemental compositions (particularly low-Ti Apollo 15 mare basalts) that are comparable to basaltic SNC meteorites [4,5]. Furthermore, lunar basalts may be mineralogically better suited as analogues of the martian surface basalts than the basaltic martian meteorites because the plagioclase feldspar in the basaltic Martian meteorites, but not in the lunar surface basalts, is largely present as maskelynite [1,2]. Analysis of lunar mare basalts my also lead to additional endmember spectra for spectral libraries. This is particularly important analysis of martian thermal emission spectra, because the spectral library apparently contains a single pigeonite spectrum derived from a synthetic sample [6].

  16. Inferred Primary Compositions of Archean Spherules Formed by the Condensation of an Impact-produced Rock Vapor Cloud, Barberton Greenstone Belt, South Africa

    Science.gov (United States)

    Krull, A. E.; Lowe, D. R.; Byerly, G. R.

    2003-01-01

    Based on the lunar cratering record, impacts were larger and more frequent on the early Earth than they are today. There is no persevered record of these early terrestrial impacts because rocks of this age have been obliterated by tectonism and erosion. The oldest known evidence of impacts on Earth lies in four beds (S1, S2, S3 and S4) in the Barberton Greenstone Belt (BGB), South Africa, ranging in age from about 3.24 to 3.47 Ga. These beds are composed in large part of sand-sized spherical particles, termed spherules, that are thought to have formed by the condensation of rock vapor clouds ejected above the atmosphere as a result of large impacts. Spherule beds S2 and S3 are both about 20 cm thick where composed entirely of fall-deposited spherules and up to a meter thick where spherules are mixed with locally derived debris. The diameters the bolides have been estimated to be between 20 and 50 km, based on bed thickness, size of the largest spherules, Ir fluence and extraterrestrial Cr.

  17. Lu-Hf AND Sm-Nd EVOLUTION IN LUNAR MARE BASALTS.

    Science.gov (United States)

    Unruh, D.M.; Stille, P.; Patchett, P.J.; Tatsumoto, M.

    1984-01-01

    Lu-Hf and Sm-Nd data for mare basalts combined with Rb-Sr and total REE data taken from the literature suggest that the mare basalts were derived by small ( less than equivalent to 10%) degrees of partial melting of cumulate sources, but that the magma ocean from which these sources formed was light REE and hf-enriched. Calculated source compositions range from lherzolite to olivine websterite. Nonmodal melting of small amounts of ilmenite ( less than equivalent to 3%) in the sources seems to be required by the Lu/Hf data. A comparison of the Hf and Nd isotopic characteristics between the mare basalts and terrestrial oceanic basalts reveals that the epsilon Hf/ epsilon Nd ratios in low-Ti mare basalts are much higher than in terrestrial ocean basalts.

  18. Mechanical Properties of Wood Flour Reinforced High Density Polyethylene Composites with Basalt Fibers

    OpenAIRE

    Lu, Guojun; Wang, Weihong; Shen, Shijie

    2014-01-01

    Basalt fibers (BFs) were surface-treated with a vinyl triethoxy silane coupling agent to improve the mechanical properties of wood fiber-reinforced high density polyethylene (HDPE) composites. Basalt fibers were characterized with SEM and FT-IR. The effects of the basalt fiber content and apparent morphology on the mechanical properties of the hybrid composites were investigated in this paper. The results show that the BF coated with the vinyl triethoxy silane coupling agent resulted in an im...

  19. Engineered barrier development for a nuclear waste repository in basalt: an integration of current knowledge

    International Nuclear Information System (INIS)

    This document represents a compilation of data and interpretive studies conducted as part of the engineered barriers program of the Basalt Waste Isolation Project. The overall objective of these studies is to provide information on barrier system designs, emplacement and isolation techniques, and chemical reactions expected in a nuclear waste repository located in the basalts underlying the Hanford Site within the state of Washington. Backfills, waste-basalt interactions, sorption, borehole plugging, etc., are among the topics discussed

  20. Experimental petrology of ancient lunar mare basalt Asuka-881757: Spinel crystallization as a petrologic indicator

    OpenAIRE

    Arai,Tomoko/Takeda,Hiroshi /Miyamoto,Masamichi

    2006-01-01

    The paucity of titanian chromites in lunar-meteorite basalt Asuka (A)-881757 is unusual compared to the general occurrence of co-existing chromites and ulvospinels in the Apollo and Luna mare basalts. The unique spinel crystallization of A-881757 is expected to hold a key to elucidate the crystallization and cooling episodes of the basalt. In this study, we investigated the possible reason for the missing chromite by conducting isothermal and cooling experiments on the bulk-rock composition o...

  1. Engineered barrier development for a nuclear waste repository in basalt: an integration of current knowledge

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M.J.

    1980-05-01

    This document represents a compilation of data and interpretive studies conducted as part of the engineered barriers program of the Basalt Waste Isolation Project. The overall objective of these studies is to provide information on barrier system designs, emplacement and isolation techniques, and chemical reactions expected in a nuclear waste repository located in the basalts underlying the Hanford Site within the state of Washington. Backfills, waste-basalt interactions, sorption, borehole plugging, etc., are among the topics discussed.

  2. 3D Finite Difference Modelling of Basaltic Region

    Science.gov (United States)

    Engell-Sørensen, L.

    2003-04-01

    The main purpose of the work was to generate realistic data to be applied for testing of processing and migration tools for basaltic regions. The project is based on the three - dimensional finite difference code (FD), TIGER, made by Sintef. The FD code was optimized (parallelized) by the author, to run on parallel computers. The parallel code enables us to model large-scale realistic geological models and to apply traditional seismic and micro seismic sources. The parallel code uses multiple processors in order to manipulate subsets of large amounts of data simultaneously. The general anisotropic code uses 21 elastic coefficients. Eight independent coefficients are needed as input parameters for the general TI medium. In the FD code, the elastic wave field computation is implemented by a higher order FD solution to the elastic wave equation and the wave fields are computed on a staggered grid, shifted half a node in one or two directions. The geological model is a gridded basalt model, which covers from 24 km to 37 km of a real shot line in horizontal direction and from the water surface to the depth of 3.5 km. The 2frac {1}{2}D model has been constructed using the compound modeling software from Norsk Hydro. The vertical parameter distribution is obtained from observations in two wells. At The depth of between 1100 m to 1500 m, a basalt horizon covers the whole sub surface layers. We have shown that it is possible to simulate a line survey in realistic (3D) geological models in reasonable time by using high performance computers. The author would like to thank Norsk Hydro, Statoil, GEUS, and SINTEF for very helpful discussions and Parallab for being helpful with the new IBM, p690 Regatta system.

  3. Nuclear waste repository in basalt: preconceptual design guidelines

    International Nuclear Information System (INIS)

    The development of the basalt waste isolation program parallels the growing need for permanent, environmentally safe, and secure means to store nuclear wastes. The repository will be located within the Columbia Plateau basalt formations where these ends can be met and radiological waste can be stored. These wastes will be stored such that the wastes may be retrieved from storage for a period after placement. After the retrieval period, the storage locations will be prepared for terminal storage. The terminal storage requirements will include decommissioning provisions. The facility boundaries will encompass no more than several square miles of land which will be above a subsurface area where the geologic makeup is primarily deep basaltic rock. The repository will receive, from an encapsulation site(s), nuclear waste in the form of canisters (not more than 18.5 feet x 16 inches in diameter) and containers (55-gallon drums). Canisters will contain spent fuel (after an interim 5-year storage period), solidified high-level wastes (HLW), or intermediate-level wastes (ILW). The containers (drums) will package the low-level transuranic wastes (LL-TRU). The storage capacity of the repository will be expanded in a time-phased program which will require that subsurface development (repository expansion) be conducted concurrently with waste storage operations. The repository will be designed to store the nuclear waste generated within the predictable future and to allow for reasonable expansion. The development and assurance of safe waste isolation is of paramount importance. All activities will be dedicated to the protection of public health and the environment. The repository will be licensed by the US Nuclear Regulatory Commission (NRC). Extensive efforts will be made to assure selection of a suitable site which will provide adequate isolation

  4. Radiation shielding properties of a novel cement–basalt mixture for nuclear energy applications

    International Nuclear Information System (INIS)

    Highlights: • Basalt fiber is a relatively cheap material that can be used as reinforcement. • Gamma-ray attenuation remains relatively stable with addition of basalt fiber. • Neutron attenuation remains relatively stable with addition of basalt fiber. • Cement–basalt mixture has a good potential for use in nuclear energy applications. - Abstract: The radiation shielding properties of a new proposed building material, a novel cement–basalt fiber mixture (CBM), are investigated. The authors analyze the possibility of this material to be a viable substitute to outgoing materials in nuclear energy applications, which will lead to a further sustained development of nuclear energy in the future. This computational study involves four types of concrete with various amounts of basalt fiber in them. The gamma-ray shielding characteristics of proposed CBM material are investigated with the help of WinXCom program, whereas the neutron shielding characteristics are computed by the Serpent code. For gamma-ray shielding, we find that the attenuation coefficients of concretes with basalt fibers are not notably influenced by the addition of fibers. For neutron shielding, additional basalt fiber in mixture presents negligible effect on neutron radiation shielding. With respect to radiation shielding, it can be concluded that basalt fibers have good potential as an addition to heavyweight concrete for nuclear energy applications

  5. Radiation shielding properties of a novel cement–basalt mixture for nuclear energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Ipbüker, Cagatay; Nulk, Helena; Gulik, Volodymyr [University of Tartu, Institute of Physics (Estonia); Biland, Alex [HHK Technologies, Houston (United States); Tkaczyk, Alan Henry, E-mail: alan@ut.ee [University of Tartu, Institute of Physics (Estonia)

    2015-04-01

    Highlights: • Basalt fiber is a relatively cheap material that can be used as reinforcement. • Gamma-ray attenuation remains relatively stable with addition of basalt fiber. • Neutron attenuation remains relatively stable with addition of basalt fiber. • Cement–basalt mixture has a good potential for use in nuclear energy applications. - Abstract: The radiation shielding properties of a new proposed building material, a novel cement–basalt fiber mixture (CBM), are investigated. The authors analyze the possibility of this material to be a viable substitute to outgoing materials in nuclear energy applications, which will lead to a further sustained development of nuclear energy in the future. This computational study involves four types of concrete with various amounts of basalt fiber in them. The gamma-ray shielding characteristics of proposed CBM material are investigated with the help of WinXCom program, whereas the neutron shielding characteristics are computed by the Serpent code. For gamma-ray shielding, we find that the attenuation coefficients of concretes with basalt fibers are not notably influenced by the addition of fibers. For neutron shielding, additional basalt fiber in mixture presents negligible effect on neutron radiation shielding. With respect to radiation shielding, it can be concluded that basalt fibers have good potential as an addition to heavyweight concrete for nuclear energy applications.

  6. Trace Element Geochemistry of Hannuoba Ultramafic Inclusion—bearing Alkali Basalts

    Institute of Scientific and Technical Information of China (English)

    支霞臣

    1990-01-01

    Presented in this paper are the trace element abundances of 16 samples of Hannuoba ultramafic inclusion-bearing aldali basalts,which were determined by instrumental neutron activation analysis and X-ray fluorescence spectrometry.The Petrogenesis of the alkali basalt suite has been modeled by batch partial melting and and Rayleigh fractional crystallization processes,The geochemical characteristics of the mantle source from where alkali basalts were derived are described in terms of variations in trace element abundances of the alkali basalt suite.

  7. Basalt fiber manufacturing technology and the possibility of its use in dentistry

    Science.gov (United States)

    Karavaeva, E.; Rogozhnikov, A.; Nikitin, V.; Cherepennikov, Yu; Lysakov, A.

    2015-11-01

    The article touches upon the technology of basalt fiber manufacturing and prospects of its use in dental practice. Two kinds of construction using basalt fiber have been proposed. The first one is a splinting construction for mobile teeth and the second one is the reinforced base for removable plate-denture. The work presents the results of the investigation of physical and mechanical properties of the constructions based on basalt fiber. It also describes the aspects of biomechanical modeling of such constructions in the ANSYS software package. The results of the investigation have proved that applying constructions using basalt fiber is highly promising for prosthetic dentistry practice.

  8. Basalt Waste Isolation Project exploratory shaft site: Final reclamation report

    International Nuclear Information System (INIS)

    The restoration of areas disturbed by activities of the Basalt Waste Isolation Project (BWIP) constitutes a unique operation at the US Department of Energy's (DOE) Hanford Site, both from the standpoint of restoration objectives and the time frame for accomplishing these objectives. The BWIP reclamation program comprises three separate projects: borehole reclamation, Near Surface Test Facility (NSTF) reclamation, and Exploratory Shaft Facility (ESF) reclamation. The main focus of this report is on determining the success of the revegetation effort 1 year after work was completed. This report also provides a brief overview of the ESF reclamation program. 21 refs., 7 figs., 14 tabs

  9. Structural Analysis of Basalt Fiber Reinforced Plastic Wind Turbine Blade

    Directory of Open Access Journals (Sweden)

    Mengal Ali Nawaz

    2014-07-01

    Full Text Available In this study, Basalt fiber reinforced plastic (BFRP wind turbine blade was analyzed and compared with Glass fiber reinforced plastic blade (GFRP. Finite element analysis (FEA of blade was carried out using ANSYS. Data for FEA was obtained by using rule of mixture. The shell element in ANSYS was used to simulate the wind turbine blade and to conduct its strength analysis. The structural analysis and comparison of blade deformations proved that BFRP wind turbine blade has better strength compared to GFRP wind turbine blade.

  10. Dissolved hydrogen and methane in the oceanic basaltic biosphere

    Science.gov (United States)

    Lin, Huei-Ting; Cowen, James P.; Olson, Eric J.; Lilley, Marvin D.; Jungbluth, Sean P.; Wilson, Samuel T.; Rappé, Michael S.

    2014-11-01

    The oceanic basaltic crust is the largest aquifer on Earth and has the potential to harbor substantial subsurface microbial ecosystems, which hitherto remains largely uncharacterized and is analogous to extraterrestrial subsurface habitats. Within the sediment-buried 3.5 Myr old basaltic crust of the eastern Juan de Fuca Ridge flank, the circulating basement fluids have moderate temperature (∼65 °C) and low to undetectable dissolved oxygen and nitrate concentrations. Sulfate, present in high concentrations, is therefore expected to serve as the major electron acceptor in this subsurface environment. This study focused on the availability and potential sources of two important electron donors, methane (CH4) and hydrogen (H2), for the subseafloor biosphere. High integrity basement fluids were collected via fluid delivery lines associated with Integrated Ocean Drilling Program (IODP) Circulation Obviation Retrofit Kits (CORKs) that extend from basement depths to outlet ports at the seafloor. Two new CORKs installed during IODP 327 in 2010, 1362A and 1362B, were sampled in 2011 and 2013. The two CORKs are superior than earlier style CORKs in that they are equipped with coated casing and polytetrafluoroethylene fluid delivery lines, reducing the interaction between casing materials with the environment. Additional samples were collected from an earlier style CORK at Borehole 1301A. The basement fluids are enriched in H2 (0.05-1.8 μmol/kg), suggesting that the ocean basaltic aquifer can support H2-driven metabolism. The basement fluids also contain significant amount of CH4 (5-32 μmol/kg), revealing CH4 as an available substrate for subseafloor basaltic habitats. The δ13C values of CH4 from the three boreholes ranged from -22.5 to -58‰, while the δ2H values ranged from -316 to 57‰. The isotopic compositions of CH4 and the molecular compositions of hydrocarbons suggest that CH4 in the basement fluids is of both biogenic and abiotic origins, varying among sites

  11. Environmental issue identification for the Basalt Waste Isolation Project

    International Nuclear Information System (INIS)

    A preliminary evaluation of environmental issues is provided in this report. It contains summary of the thought process that was used during the area characterization studies for a geological repository for high-level radioactive wastes. Environmental issues are discussed separately for construction, operation, and long term isolation aspects of a repository in basalt. During construction the primary environmental concerns are public perception and water resources; intermediate concerns are air quality, ecosystems, physical resources, and cultural and social resources. During operation, the primary environmental issues concern the transport of radioactive materials and physical resources. Long term environmental issues envolve water resources and borehole plugging

  12. Basalt weathering in an Arctic Mars-analog site

    Science.gov (United States)

    Yesavage, Tiffany; Thompson, Aaron; Hausrath, Elisabeth M.; Brantley, Susan L.

    2015-07-01

    The martian surface has undergone chemical and physical weathering in the past, and these processes may continue intermittently today. To explore whether martian rocks are likely to retain features indicative of weathering, we investigated how basaltic material weathers on Earth. Specifically, we investigated weathering of a Quaternary-aged basaltic flow at the Sverrefjell volcano in Svalbard, above the Arctic Circle. This flow weathered since deglaciation under cold, dry (characterized the mineralogical and morphological properties using electron microscopy (EM), X-ray diffraction (XRD), infrared (IR) spectroscopy and selective chemical dissolution. In addition, we ran colloidal dispersion, wetting/drying, and freeze/thaw experiments. In the regolith, we observed concentrations of short-range ordered (SRO) phases similar to those observed in warmer, wetter volcanic ash soils. IR and EM analyses of the clay-sized fraction were consistent with allophane as the predominant secondary phase. Selective chemical extractions targeting SRO phases indicated lower Al/Si ratios than those observed in volcanic soils reported in warmer localities, which we attribute to Si-rich allophane and/or abundant Si-rich rock coatings. The oxic circumneutral-pH colloidal dispersion experiments mobilized Al, Fe and Ti primarily as 260-415 nm particles and Ca, Mg and Na as solutes. Si was lost both in the colloidal and dissolved forms. Dispersed colloids likely contain allophane and ferrihydrite. Under anoxic conditions, dissolution of Fe oxide cements also released fines. The experiments help to explain elemental loss from the clay-sized regolith fraction at Svalbard: observed depletions in Ca, K, Mg and Na were likely due to solute loss, while particle-reactive Al, Fe, Si and Ti were mostly retained. Wetting/drying was observed to be as effective as freeze/thaw in driving material loss. It is thus possible that cyclic adsorption of water onto basaltic rocks in this dry climate may result

  13. Fire performance of basalt FRP mesh reinforced HPC thin plates

    DEFF Research Database (Denmark)

    Hulin, Thomas; Hodicky, Kamil; Schmidt, Jacob Wittrup;

    2013-01-01

    An experimental program was carried out to investigate the influence of basalt FRP (BFRP) reinforcing mesh on the fire behaviour of thin high performance concrete (HPC) plates applied to sandwich elements. Samples with BFRP mesh were compared to samples with no mesh, samples with steel mesh and...... samples displaying a full sandwich structure. Final results confirmed the bond loss between concrete and BFRP mesh with temperature. The available void where the epoxy burnt away allowed the concrete matrix to release pressure and limit pore stresses, delaying spalling. It also reduced the mechanical...

  14. Pulsating water jet as a tool for basalt surface treatment

    Czech Academy of Sciences Publication Activity Database

    Klich, Jiří; Sitek, Libor; Foldyna, Josef; Ščučka, Jiří

    Kraków: Department of Mining, Dressing and Transporting Machines Faculty of Mechanical Engineering and Robotics , University of Science and Technology AGH Kraków, 2011 - (Kasza, P.; Boloz, L.), s. 63-72 ISBN 978-83-930353-4-2. [Nowoczesne metody eksploatacji wegla skal zwiezlych - Medzynarodowa konferencja techniki urabiania TUR 2011 /7./. Kraków-Krynica (PL), 20.09.2011-23.09.2011] Grant ostatní: GA MŠk(CZ) ED2.1.00/03/0082 Institutional research plan: CEZ:AV0Z30860518 Keywords : pulsating water jet * surface treatment * basalt Subject RIV: JQ - Machines ; Tools

  15. Basalt features observed in outcrops, cores, borehole video imagery and geophysical logs, and basalt hydrogeologic study at the Idaho National Engineering Laboratory, Eastern Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Bennecke, W.M.

    1996-10-01

    A study was undertaken to examine permeable zones identified in boreholes open to the underlying basalt and to describe the vertical cross flows present in the boreholes. To understand the permeable zones in the boreholes detailed descriptions and measurements of three outcrops in the Snake River Plain, three cores at the Idaho Chemical Processing Plant (ICPP) at the INEL, and over fifty borehole TV logs from the INEL were carried out. Based on the observations made on the three outcrops an idealized basalt lava flow model was generated that used a set of nomenclature that would be standard for the basalt lava flows studied. An upper vesicular zone, a sometimes absent columnar zone, central zone, and lower vesicular zone make up the basalt lava flow model. The overall distinction between the different zones are based on the vesicle shape size, vesicularity, and fractures present. The results of the studies also indicated that the basalt lava flows at the INEL are distal to medial facies pahoehoe lava flows with close fitting contacts. The most permeable zones identified in these basalts are fractured vesiculated portions of the top of the lava flow, the columnar areas, and basalt-flow contacts in order of importance. This was determined from impeller flowmeter logging at the INEL. Having this information a detailed stratigraphy of individual basalt lava flows and the corresponding permeable units were generated. From this it was concluded that groundwater flow at the ICPP prefers to travel along thin basalt lava flows or flow-units. Flow direction and velocity of intrawell flows detected by flowmeter is controlled by a nearby pumping well.

  16. Basalt features observed in outcrops, cores, borehole video imagery and geophysical logs, and basalt hydrogeologic study at the Idaho National Engineering Laboratory, Eastern Idaho

    International Nuclear Information System (INIS)

    A study was undertaken to examine permeable zones identified in boreholes open to the underlying basalt and to describe the vertical cross flows present in the boreholes. To understand the permeable zones in the boreholes detailed descriptions and measurements of three outcrops in the Snake River Plain, three cores at the Idaho Chemical Processing Plant (ICPP) at the INEL, and over fifty borehole TV logs from the INEL were carried out. Based on the observations made on the three outcrops an idealized basalt lava flow model was generated that used a set of nomenclature that would be standard for the basalt lava flows studied. An upper vesicular zone, a sometimes absent columnar zone, central zone, and lower vesicular zone make up the basalt lava flow model. The overall distinction between the different zones are based on the vesicle shape size, vesicularity, and fractures present. The results of the studies also indicated that the basalt lava flows at the INEL are distal to medial facies pahoehoe lava flows with close fitting contacts. The most permeable zones identified in these basalts are fractured vesiculated portions of the top of the lava flow, the columnar areas, and basalt-flow contacts in order of importance. This was determined from impeller flowmeter logging at the INEL. Having this information a detailed stratigraphy of individual basalt lava flows and the corresponding permeable units were generated. From this it was concluded that groundwater flow at the ICPP prefers to travel along thin basalt lava flows or flow-units. Flow direction and velocity of intrawell flows detected by flowmeter is controlled by a nearby pumping well

  17. Radiometric dating of bioalteration textures in Archean basaltic metaglasses

    International Nuclear Information System (INIS)

    Full text: Direct in-situ U-Pb dating of titanite which infills tubular bioalteration textures in pillow basalt rims from the ∼ 3.35 Ga Euro basalt of the Pilbara craton, W. Australia (PWA) confirms their Archean age. A novel in situ laser ablation multi-collector-ICP-MS technique is here reported that has enabled the first radiometric age determination of an Archean biosignature. Multiple lines of evidence suggest that these tubular bioalteration textures formed by microbial etching of formerly glassy Archean lavas that were subsequently mineralized by titanite. Firstly, there are striking morphological similarities between tubular structures from both the Pilbara and Barberton (BGB) cratons and bioalteration textures in modern glasses. Secondly, x-ray mapping indicates C enriched along the margins of the tubular structures from both the BGB and PWA. Thirdly, disseminated carbonates in the BGB pillow rims have C-isotopes depleted by as much as -16 %o, which is consistent with microbial oxidation of organic matter. A pre-metamorphic age for these microtubes is indicated by their segmentation caused by metamorphic chlorite overgrowths. A laser ablation spot size of ∼ 40 μm was used to analyze titanite in the 'root zones' at the centre of microtube clusters. Thirteen analyzes upon three thin sections gave a weighted average 206Pb/238U age of 2921 ± 110 Ma. This corresponds to the oldest metamorphic episode that has affected the PWA rocks and gives a minimum, late Archean age estimate for the bioalteration. (author)

  18. The sealing performance of bentonite/crushed basalt borehole plugs

    International Nuclear Information System (INIS)

    Mixtures of crushed rock and bentonite are considered for backfilling and sealing high-level nuclear waste repositories. Many variables affect the hydraulic conductivity of such mixtures, including the size and shape of the rock particles, method of mixing and emplacement, water content and density of the clay, and the weight ratio of rock to clay. Mixtures of crushed basalt and bentonite have been tested in two types of permeameters, 20 cm diameter stainless steel permeameters and 10 cm diameter PVC permeameters. Plugs were installed as a single lift or in many lifts; the water content of the clay ranged from air-dry to as high as 200%. Preliminary results show that a mixture of 75% crushed basalt and 25% bentonite has a hydraulic conductivity between 1 x 10-9 cm/s and 2.5 x 10-8 cm/s. In some cases, preferential flow paths have developed (possibly as a result of the montmorillonite washing out of the crushed rock matrix), giving hydraulic conductivities as high as 1 x 10-4 cm/s. Other ratios of rock to clay have similar bimodal results. The probability of failure is decreased by including a higher percentage of clay in the plug, crushing the rock finer, and evenly mixing the crushed rock and clay. 136 refs., 50 figs., 7 tabs

  19. Los Angeles: The most differentiated basaltic martian meteorite

    Science.gov (United States)

    Rubin, Alan E.; Warren, Paul H.; Greenwood, James P.; Verish, Robert S.; Leshin, Laurie A.; Hervig, Richard L.; Clayton, Robert N.; Mayeda, Toshiko K.

    2000-11-01

    Los Angeles is a new martian meteorite that expands the compositional range of basaltic shergottites. Compared to Shergotty, Zagami, QUE94201, and EET79001-B, Los Angeles is more differentiated, with higher concentrations of incompatible elements (e.g., La) and a higher abundance of late-stage phases such as phosphates and K-rich feldspathic glass. The pyroxene crystallization trend starts at compositions more ferroan than in other martian basalts. Trace elements indicate a greater similarity to Shergotty and Zagami than to QUE94201 or EET79001-B, but the Mg/Fe ratio is low even compared to postulated parent melts of Shergotty and Zagami. Pyroxene in Los Angeles has 0.7 4-μm-thick exsolution lamellae, ˜10 times thicker than those in Shergotty and Zagami. Opaque oxide compositions suggest a low equilibration temperature at an oxygen fugacity near the fayalite-magnetite-quartz buffer. Los Angeles cooled more slowly than Shergotty and Zagami. Slow cooling, coupled with the ferroan bulk composition, produced abundant fine-grained intergrowths of fayalite, hedenbergite, and silica, by the breakdown of pyroxferroite. Shock effects in Los Angeles include maskelynitized plagioclase, pyroxene with mosaic extinction, and rare fault zones. One such fault ruptured a previously decomposed zone of pyroxferroite. Although highly differentiated, the bulk composition of Los Angeles is not close to the low-Ca/Si composition of the globally wind-stirred soil of Mars.

  20. Seismic wave propagation through surface basalts - implications for coal seismic surveys

    Science.gov (United States)

    Sun, Weijia; Zhou, Binzhong; Hatherly, Peter; Fu, Li-Yun

    2010-02-01

    Seismic reflection surveying is one of the most widely used and effective techniques for coal seam structure delineation and risk mitigation for underground longwall mining. However, the ability of the method can be compromised by the presence of volcanic cover. This problem arises within parts of the Bowen and Sydney Basins of Australia and seismic surveying can be unsuccessful. As a consequence, such areas are less attractive for coal mining. Techniques to improve the success of seismic surveying over basalt flows are needed. In this paper, we use elastic wave-equation-based forward modelling techniques to investigate the effects and characteristics of seismic wave propagation under different settings involving changes in basalt properties, its thickness, lateral extent, relative position to the shot position and various forms of inhomogeneity. The modelling results suggests that: 1) basalts with high impedance contrasts and multiple flows generate strong multiples and weak reflectors; 2) thin basalts have less effect than thick basalts; 3) partial basalt cover has less effect than full basalt cover; 4) low frequency seismic waves (especially at large offsets) have better penetration through the basalt than high frequency waves; and 5) the deeper the coal seams are below basalts of limited extent, the less influence the basalts will have on the wave propagation. In addition to providing insights into the issues that arise when seismic surveying under basalts, these observations suggest that careful management of seismic noise and the acquisition of long-offset seismic data with low-frequency geophones have the potential to improve the seismic results.

  1. Physics of crustal fracturing and chert dike formation triggered by asteroid impact, ˜3.26 Ga, Barberton greenstone belt, South Africa

    Science.gov (United States)

    Sleep, Norman H.; Lowe, Donald R.

    2014-04-01

    asteroid impacts, reflected in the presence of spherule beds in the 3.2-3.5 Ga Barberton greenstone belt (BGB), South Africa, generated extreme seismic waves. Spherule bed S2 provides a field example. It locally lies at the contact between the Onverwacht and Fig Tree Groups in the BGB, which formed as a result of the impact of asteroid (possibly 50 km diameter). Scaling calculations indicate that very strong seismic waves traveled several crater diameters from the impact site, where they widely damaged Onverwacht rocks over much of the BGB. Lithified sediments near the top of the Onverwacht Group failed with opening-mode fractures. The underlying volcanic sequence then failed with normal faults and opening-mode fractures. Surficial unlithified sediments liquefied and behaved as a fluid. These liquefied sediments and some impact-produced spherules-filled near-surface fractures, today represented by swarms of chert dikes. Strong impact-related tsunamis then swept the seafloor. P waves and Rayleigh waves from the impact greatly exceeded the amplitudes of typical earthquake waves. The duration of extreme shaking was also far longer, probably hundreds of seconds, than that from strong earthquakes. Dynamic strains of ˜10-3 occurred from the surface and downward throughout the lithosphere. Shaking weakened the Onverwacht volcanic edifice and the surface layers locally moved downhill from gravity accommodated by faults and open-mode fractures. Coast-parallel opening-mode fractures on the fore-arc coast of Chile, formed as a result of megathrust events, are the closest modern analogs. It is even conceivable that dynamic stresses throughout the lithosphere initiated subduction beneath the Onverwacht rocks.

  2. Intracanyon basalt lavas of the Debed River (northern Armenia), part of a Pliocene-Pleistocene continental flood basalt province in the South Caucasus

    Science.gov (United States)

    Sheth, Hetu; Meliksetian, Khachatur; Gevorgyan, Hripsime; Israyelyan, Arsen; Navasardyan, Gevorg

    2015-03-01

    Late Pliocene to Early Pleistocene (~ 3.25-2.05 Ma), 200-400 m thick basalt lavas outcrop in the South Caucasus region, including the Kars-Erzurum Plateau (northeastern Turkey), the Javakheti Plateau (Georgia-Armenia), and the Lori Plateau (northern Armenia). These fissure-fed, rapidly erupted fluid lavas filled pre-existing river valleys over many tens of kilometres. The basalts exposed in the Debed River canyon, northern Armenia, are ~ 200 m thick and of three morphological types: (1) basal pillow basalts and hyaloclastites, overlain by (2) columnar-jointed pahoehoe sheet flows, in turn overlain by (3) slabby pahoehoe and rubbly pahoehoe flows. The lower and middle lavas show evidence for damming of river drainage, like many lavas of the Columbia River flood basalt province, Scotland, Ireland, and Iceland. There is also evidence for syn-volcanic faulting of the early lavas. Related basalts also outcrop in the Gegham Uplands and the Hrazdan River basin in Armenia. This 3.25-2.05 Ma South Caucasus basalt province, covering parts of Turkey, Georgia and Armenia, has an estimated areal extent of ~ 15,000 km2 and volume of ~ 2250 km3. Because its main geological features are remarkably like those of many continental flood basalt (CFB) provinces, we consider it a true, albeit small, CFB province. It is the smallest and youngest CFB in the world. An analogue closely similar in major features is the Late Miocene Altos de Jalisco CFB province in the western Trans-Mexican Volcanic Belt. Both provinces formed during lithospheric pull-apart and transtensional faulting. Their broader significance is in showing flood basalt size distribution to be a continuum without natural breaks, with implications for geodynamic models.

  3. Conceptual model for regional radionuclide transport from a basalt repository site. Final draft, technical memorandum

    International Nuclear Information System (INIS)

    This technical memorandum was prepared to: (1) describe a typical basalt radionuclide repository site, (2) describe geologic and hydrologic processes associated with regional radionuclide transport in basalts, (3) define the parameters required to model regional radionuclide transport from a basalt repository site, and (4) develop a ''conceptual model'' of radionuclide transport from a basalt repository site. In a general hydrological sense, basalts may be described as layered sequences of aquifers and aquitards. The Columbia River Basalt, centered near the semi-arid Pasco Basin, is considered by many to be typical basalt repository host rock. Detailed description of the flow system including flow velocities with high-low hydraulic conductivity sequences are not possible with existing data. However, according to theory, waste-transport routes are ultimately towards the Columbia River and the lengths of flow paths from the repository to the biosphere may be relatively short. There are many physical, chemical, thermal, and nuclear processes with associated parameters that together determine the possible pattern of radionuclide migration in basalts and surrounding formations. Brief process descriptions and associated parameter lists are provided. Emphasis has been placed on the use of the distribution coefficient in simulating ion exchange. The use of the distribution coefficient approach is limited because it takes into account only relatively fast mass transfer processes. In general, knowledge of hydrogeochemical processes is primitive

  4. Prokaryotic diversity, distribution, and insights into their role in biogeochemical cycling in marine basalts

    Energy Technology Data Exchange (ETDEWEB)

    Mason, Olivia U.; Di Meo-Savoie, Carol A.; Van Nostrand, Joy D.; Zhou, Jizhong; Fisk, Martin R.; Giovannoni, Stephen J.

    2008-09-30

    We used molecular techniques to analyze basalts of varying ages that were collected from the East Pacific Rise, 9 oN, from the rift axis of the Juan de Fuca Ridge, and from neighboring seamounts. Cluster analysis of 16S rDNA Terminal Restriction Fragment Polymorphism data revealed that basalt endoliths are distinct from seawater and that communities clustered, to some degree, based on the age of the host rock. This age-based clustering suggests that alteration processes may affect community structure. Cloning and sequencing of bacterial and archaeal 16S rRNA genes revealed twelve different phyla and sub-phyla associated with basalts. These include the Gemmatimonadetes, Nitrospirae, the candidate phylum SBR1093 in the c, andin the Archaea Marine Benthic Group B, none of which have been previously reported in basalts. We delineated novel ocean crust clades in the gamma-Proteobacteria, Planctomycetes, and Actinobacteria that are composed entirely of basalt associated microflora, and may represent basalt ecotypes. Finally, microarray analysis of functional genes in basalt revealed that genes coding for previously unreported processes such as carbon fixation, methane-oxidation, methanogenesis, and nitrogen fixation are present, suggesting that basalts harbor previously unrecognized metabolic diversity. These novel processes could exert a profound influence on ocean chemistry.

  5. Surface modification of basalt with silane coupling agent on asphalt mixture moisture damage

    Science.gov (United States)

    Min, Yahong; Fang, Ying; Huang, Xiaojun; Zhu, Yinhui; Li, Wensheng; Yuan, Jianmin; Tan, Ligang; Wang, Shuangyin; Wu, Zhenjun

    2015-08-01

    A new silane coupling agent was synthesized based on γ-(methacryloyloxy) propyltrimethoxysilane (KH570). The surface of basalt rocks was modified by KH570 and the new silane coupling agent (NSCA), and the interfacial interaction between silane coupling agent and basalt was also studied. Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis showed that the silane coupling agent molecule bound strongly with basalt rocks. Scanning electronic microscopy (SEM) observation showed that a thin layer of coupling agent was formed on the surface of modified basalt. The boiling test and immersion Marshall test confirmed that the moisture sensitivity of basalt modified with the new silane coupling agent increased more significantly than that untreated and treated with KH570. The Retained Marshall Strength of basalt modified with the new coupling agent increased from 71.74% to 87.79% compared with untreated basalt. The results indicated that the new silane coupling agent played an important role in improving the interfacial performance between basalt and asphalt.

  6. From mantle roots to surface eruptions: Cenozoic and Mesozoic continental basaltic magmatism

    Czech Academy of Sciences Publication Activity Database

    Kämpf, H.; Németh, K.; Puziewicz, J.; Mrlina, Jan; Geissler, W.H.

    2015-01-01

    Roč. 104, č. 8 (2015), s. 1909-1912. ISSN 1437-3254 Institutional support: RVO:67985530 Keywords : continental basaltic volcanism * BASALT 2013 conference * Cenozoic * Mesozoic Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.093, year: 2014

  7. Spinel from Apollo 12 Olivine Mare Basalts: Chemical Systematics of Selected Major, Minor, and Trace Elements

    Science.gov (United States)

    Papike, J. J.; Karner, J. M.; Shearer, C. K.; Spilde, M. N.

    2002-01-01

    Spinels from Apollo 12 Olivine basalts have been studied by Electron and Ion microprobe techniques. The zoning trends of major, minor and trace elements provide new insights into the conditions under which planetary basalts form. Additional information is contained in the original extended abstract.

  8. Importance of plagioclase morphology and composition in magmagenesis of the Carlsberg Ridge basalts

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.; Banerjee, R.

    The morphology and chemical composition of more than 200 plagioclase crystals in the Carlsberg Ridge basalts (3~'35' and 3~'41'N) in relation to the magmagenesis of the basalts is examined. The results indicate that the different morphotypes...

  9. Lu-Hf and Sm-Nd evolution in lunar mare basalts

    International Nuclear Information System (INIS)

    Lu-Hf and Sm-Nd data for mare basalts combined with Rb-Sr and total REE data taken from the literature suggest that the mare basalts were derived by small (< or =10%) degrees of partial melting of cumulate sources, but that the magma ocean from which these sources formed was light REE and Hf-enriched. Calculated source compositions range fromm lherzolite to olivine websterite. Nonmodal melting of small amounts of ilmenite (< or =3%) in the sources seems to be required by the Lu/Hf data. A comparison of the Hf and Nd isotopic characteristics between the mare basalts and terrestrial oceanic basalts reveals that the epsilonHf/epsilonNd ratios of low-Ti mare basalts are much higher than in terrestrial oceanic basalts. The results are qualitatively consistent with the hypothesis that terrestrial basalt sources are partial melt residues whereas mare basalt sources are cumulates. Alternatively, the results may imply that the terrestrial mantle has evolved in two (or more) stages of evolution, and that the net effect was depletion of the mantle during the first approx.1-3 b.y. followed by enrichment during the last 1-2 b.y.; or simply that there is a difference in Lu-Hf crystal-liquid partitioning (relative to Sm-Nd) between the lunar and terrestrial mantles

  10. Briefing to US Nuclear Regulatory Commission - staff Basalt Waste Isolation Project

    International Nuclear Information System (INIS)

    Items covered in the briefing include issues, work elements and data needs in the basalt waste isolation project, site data in site characterization report (SCR), geology and hydrology, waste package and geochemistry data in SCR, performance assessment, near-surface test facility, hydrofracturing, repository design in basalt, drilling and testing, in-situ testing

  11. Silicon isotope systematics of acidic weathering of fresh basalts, Kilauea Volcano, Hawai’i

    OpenAIRE

    Chemtob, Steven M.; Rossman, George R.; Young, Edward D.; Ziegler, Karen; Moynier, Fréderic; Eiler, John M.; Hurowitz, Joel A.

    2015-01-01

    Silicon stable isotopes are fractionated by a host of low-temperature aqueous processes, making them potentially useful as a weathering proxy. Here we characterize the silicon isotope signature of surficial chemical weathering of glassy basaltic lava flows at Kilauea Volcano, Hawaii. Fresh basalt flow surfaces (

  12. Automated interpretation of nuclear and electrical well loggings for basalt characterization (case study from southern Syria)

    International Nuclear Information System (INIS)

    Nuclear well logging, including natural gamma ray, density and neutron-porosity techniques are used with electrical well logging of long and short normal techniques in order to characterize the large extended basaltic areas in southern Syria. Four kinds of basalt have been identified: hard massive basalt, hard basalt, pyroclastic basalt and the alteration basalt products, clay, based on a statistical analysis approach with the threshold concept. The statistical conditions for such basalt characterization have been programmed in the present research to automatically interpret the well logging data for establishing and predicting the lithological cross-section of the studied well. A specific computer program has been written in Delphi for such purposes. The program is flexible and it can be used for other well logging applications by changing the statistical conditions and the well logging parameters. The program has been successfully tested on the Kodanah well logging data in southern Syria. - Highlights: ► Automated interpretation of nuclear and electrical well logging data have been proposed. ► Statistical conditions already described have been programmed for basalt characterization. ► Delphi program has been written for such automated interpretation. ► Geological cross-section has been automatically established by such interpretation. ► The program has been tested on Kodanah well logging in southern Syria.

  13. Post-Columbia River Basalt Group stratigraphy and map compilation of the Columbia Plateau, Oregon

    International Nuclear Information System (INIS)

    This report presents the results of reconnaissance mapping of sedimentary deposits and volcanic rocks overlying the Columbia River Basalt. The project area covers parts of the Dalles, Pendleton, Grangeville, Baker, Canyon City, and Bend. The mapping was done to provide stratigraphic data on the sedimentary deposits and volcanic rocks overlying the Columbia River Basalt Group. 160 refs., 16 figs., 1 tab

  14. Searching for neuKREEP: An EMP study of Apollo 11 Group A basalts

    Science.gov (United States)

    Jerde, Eric A.; Taylor, Lawrence A.

    1993-01-01

    The Apollo 11 and 17 landing sites are characterized by the presence of high-Ti basalts (TiO2 greater than 6 percent). The Group A basalts of Apollo 11 have elevated K compositions (greater than 2000 ppm); and are enriched in incompatible trace elements relative to the other types of high-Ti basalt found in the region. These unique basalts also are the youngest of all high-Ti basalts, with an age of 3.56 +/- 0.02 Ga. Recent modelling of the Apollo 11 Group A basalts by Jerde et al. has demonstrated that this unique variety of high-Ti basalt may have formed through fractionation of a liquid with the composition of the Apollo 11 orange glass, coupled with assimilation of evolved material (dubbed neuKREEP and having similarities to lunar quartz monzodiorite). Assimilation of this material would impart its REE signature on the liquid, resulting in the elevated REE abundances observed. Minerals such as whitlockite which contain a large portion of the REE budget can be expected to reflect the REE characteristics of the assimilant. To this end, an examination of the whitlockite present in the Apollo 11 Group A basalts was undertaken to search for evidence of the neuKREEP material assimilated.

  15. Deep-ocean basalts: inert gas content and uncertainties in age dating.

    Science.gov (United States)

    Noble, C S; Naughton, J J

    1968-10-11

    The radiogenic argon and helium contents of three basalts erupted into the deep ocean from an active volcano (Kilauea) have been measured. Ages calculated from these measurements increase with sample depth up to 22 million years for lavas deduced to be recent. Caution is urged in applying dates from deep-ocean basalts in studies on ocean-floor spreading. PMID:17779379

  16. Effect of Moisture Absorption Behavior on Mechanical Properties of Basalt Fibre Reinforced Polymer Matrix Composites

    Directory of Open Access Journals (Sweden)

    Amuthakkannan Pandian

    2014-01-01

    Full Text Available The study of mechanical properties of fibre reinforced polymeric materials under different environmental conditions is much important. This is because materials with superior ageing resistance can be satisfactorily durable. Moisture effects in fibre reinforced plastic composites have been widely studied. Basalt fibre reinforced unsaturated polyester resin composites were subjected to water immersion tests using both sea and normal water in order to study the effects of water absorption behavior on mechanical properties. Composites specimens containing woven basalt, short basalt, and alkaline and acid treated basalt fibres were prepared. Water absorption tests were conducted by immersing specimens in water at room temperature for different time periods till they reached their saturation state. The tensile, flexural, and impact properties of water immersed specimens were conducted and compared with dry specimens as per the ASTM standard. It is concluded that the water uptake of basalt fibre is considerable loss in the mechanical properties of the composites.

  17. Correlation between compressive strength and ultrasonic pulse velocity of high strength concrete incorporating chopped basalt fibre

    Science.gov (United States)

    Shafiq, Nasir; Fadhilnuruddin, Muhd; Elshekh, Ali Elheber Ahmed; Fathi, Ahmed

    2015-07-01

    Ultrasonic pulse velocity (UPV), is considered as the most important test for non-destructive techniques that are used to evaluate the mechanical characteristics of high strength concrete (HSC). The relationship between the compressive strength of HSC containing chopped basalt fibre stands (CBSF) and UPV was investigated. The concrete specimens were prepared using a different ratio of CBSF as internal strengthening materials. The compressive strength measurements were conducted at the sample ages of 3, 7, 28, 56 and 90 days; whilst, the ultrasonic pulse velocity was measured at 28 days. The result of HSC's compressive strength with the chopped basalt fibre did not show any improvement; instead, it was decreased. The UPV of the chopped basalt fibre reinforced concrete has been found to be less than that of the control mix for each addition ratio of the basalt fibre. A relationship plot is gained between the cube compressive strength for HSC and UPV with various amounts of chopped basalt fibres.

  18. Experimental alteration of basalt glass applied to the alteration of nuclear waste glass

    International Nuclear Information System (INIS)

    The main objective of the experiments was to produce in the laboratory an altered basalt glass similar to basalt glass altered in a natural environment. This objective has been accomplished with a very good correlation between the observed alteration of basalt glass in a natural environment with that in the laboratory. The formation of the amorphous hydration layer, smectite, analcime, calcium carbonate, and thomsonite all have been observed in natural glass samples that have undergone palagonitization. The SRL 165 glass reacts to a greater extent than the synthetic basalt glass under the same conditions. The alteration of SRL 165 glass produced a smectite clay, analcime, and gyrolite similar to that produced by the synthetic basalt glass

  19. A preliminary analysis of lunar extra-mare basalts - Distribution, compositions, ages, volumes, and eruption styles

    Science.gov (United States)

    Whitford-Stark, J. L.

    1982-01-01

    Extra-mare basalts occupy 8.5% of the lunar basalt area and comprise 1% of the total mare basalt volume. They are preferentially located where the crust is thin and topographically low. In terms of age, eruption style, and composition they are as variable as the mare basalts. In some instances extrusion in extra-mare craters was preceded by floor-fracturing whereas in other cases it apparently was not. The volume of lava erupted may have been controlled more by the volume of magma produced than by hydrostatic effects. A minimum of nearly 1300 separate basalt eruptions is indicated; the true value could be nearer 30,000 separate eruptions.

  20. Is plagioclase removal responsible for the negative Eu anomaly in the source regions of mare basalts?

    International Nuclear Information System (INIS)

    The nearly ubiquitous presence of a negative Eu anomaly in the mare basalts has been suggested to indicate prior separation and flotation of plagioclase from the basalt source region during its crystallization from a lunar magma ocean (LMO). Are there any mare basalts derived from a mantle source which did not experience prior plagioclase separation? Crystal chemical rationale for REE substitution in pyroxene suggests that the combination of REE size and charge, M2 site characteristics of pyroxene, fO2, magma chemistry, and temperature may account for the negative Eu anomaly in the source region of some types of primitive, low TiO2 mare basalts. This origin for the negative Eu anomaly does not preclude the possibility of the LMO as many mare basalts still require prior plagioclase crystallization and separation and/or hybridization involving a KREEP component

  1. Constitutive equations of basalt filament tows under quasi-static and high strain rate tension

    International Nuclear Information System (INIS)

    The tensile properties of basalt filament tows were tested at quasi-static (0.001 s-1) and high strain rates (up to 3000 s-1) with MTS materials tester (MTS 810.23) and split Hopkinson tension bar (SHTB), respectively. Experimental results showed that the mechanical properties of the basalt filament tows were rather sensitive to strain rate. Specifically, the stiffness and failure stress of the basalt filament tows increased distinctly as the strain rate increased, while the failure strain decreased. From scanning electronic microscope (SEM) photographs of the fracture surface, it is indicated that the basalt filament tows failed in a more brittle mode and the fracture surface got more regular as the strain rate increases. The strength distributions of the basalt filament tows have been evaluated by a single Weibull distribution function. The curve predicted from the single Weibull distribution function was in good agreement with the experimental data points.

  2. Reference waste form, basalts, and ground water systems for waste interaction studies

    Energy Technology Data Exchange (ETDEWEB)

    Deju, R.A.; Ledgerwood, R.K.; Long, P.E.

    1978-09-01

    This report summarizes the type of waste form, basalt, and ground water compositions to be used in theoretical and experimental models of the geochemical environment to be simulated in studying a typical basalt repository. Waste forms to be used in the experiments include, and are limited to, glass, supercalcine, and spent unreprocessed fuel. Reference basalts selected for study include the Pomona member and the Umtanum Unit, Shwana Member, of the Columbia River Basalt Group. In addition, a sample of the Basalt International Geochemical Standard (BCR-1) will be used for cross-comparison purposes. The representative water to be used is of a sodium bicarbonate composition as determined from results of analyses of deep ground waters underlying the Hanford Site. 12 figures, 13 tables.

  3. Basalt fiber reinforced porous aggregates-geopolymer based cellular material

    Science.gov (United States)

    Luo, Xin; Xu, Jin-Yu; Li, Weimin

    2015-09-01

    Basalt fiber reinforced porous aggregates-geopolymer based cellular material (BFRPGCM) was prepared. The stress-strain curve has been worked out. The ideal energy-absorbing efficiency has been analyzed and the application prospect has been explored. The results show the following: fiber reinforced cellular material has successively sized pore structures; the stress-strain curve has two stages: elastic stage and yielding plateau stage; the greatest value of the ideal energy-absorbing efficiency of BFRPGCM is 89.11%, which suggests BFRPGCM has excellent energy-absorbing property. Thus, it can be seen that BFRPGCM is easy and simple to make, has high plasticity, low density and excellent energy-absorbing features. So, BFRPGCM is a promising energy-absorbing material used especially in civil defense engineering.

  4. Geoscience parameter data base handbook: granites and basalts

    International Nuclear Information System (INIS)

    The Department of Energy has the responsibility for selecting and constructing Federal repositories for radioactive waste. The Nuclear Regulatory Commission must license such repositories prior to construction. The basic requirement in the geologic disposal of radioactive waste is stated as: placement in a geologic host whereby the radioactive waste is not in mechanical, thermal or chemical equilibrium with the object of preventing physical or chemical migration of radionuclides into the biosphere or hydrosphere in hazardous concentration (USGS, 1977). The object of this report is to document the known geologic parameters of large granite and basalt occurrences in the coterminous United States, for future evaluation in the selection and licensing of radioactive waste repositories. The description of the characteristics of certain potential igneous hosts has been limited to existing data pertaining to the general geologic character, geomechanics, and hydrology of identified occurrences. A description of the geochemistry is the subject of a separate report

  5. On anomalously magnetic basalt lavas from Stardalur, Iceland

    International Nuclear Information System (INIS)

    In an attempt to explain an exceptionally strong magnetic anomaly near Stardalur, SW-Iceland, a 200 m deep hole was drilled into its centre and the core subjected to various mineralogical and geophysical measurements. In Moessbauer spectra of bulk samples from depths between 45 and 170 m the magnetic phase is predominant and consists of very pure magnetite. The area ratio for the components with hyperfine fields of 46 and 49 T is approximately 2. Comparison with spectra of selected basalt lavas showing similar magnetic properties indicates a distinctive difference. The strong remanent magnetism of the Stardalur samples can be explained by a combination of unusually high concentration in the rocks of pure magnetite, its small grain size and a strong magnetic field appending its formation. It is suggested that both the composition of the magnetic phase and the strong magnetic field were brought about by hydrothermal alteration. (orig.)

  6. Nuclear waste repository in basalt: a design description

    International Nuclear Information System (INIS)

    The conceptual design of a nuclear waste repository in basalt is described. Nuclear waste packages are placed in holes drilled into the floor of tunnels at a depth of 3700 ft. About 100 miles of tunnels are required to receive 35,000 packages. Five shafts bring waste packages, ventilation air, excavated rock, personnel, material, and services to and from the subsurface. The most important surface facility is the waste handling building, located over the waste handling shaft, where waste is received and packaged for storage. Two independent ventilation systems are provided to avoid potential contamination of spaces that do not contain nuclear waste. Because of the high temperatures at depth, an elaborate air chilling system is provided. Because the waste packages deliver a considerable amount of heat energy to the rock mass, particular attention is paid to heat transfer and thermal stress studies. 3 references, 31 figures, 3 tables

  7. Aeromagnetic Expression of Buried Basaltic Volcanoes Near Yucca Mountain, Nevada

    Science.gov (United States)

    O'Leary, D. W.; Mankinen, E.A.; Blakely, R.J.; Langenheim, V.E.; Ponce, D.A.

    2002-01-01

    A high-resolution aeromagnetic survey has defined a number of small dipolar anomalies indicating the presence of magnetic bodies buried beneath the surface of Crater Flat and the Amargosa Desert. Results of potential-field modeling indicate that isolated, small-volume, highly magnetic bodies embedded within the alluvial deposits of both areas produce the anomalies. Their physical characteristics and the fact that they tend to be aligned along major structural trends provide strong support for the hypothesis that the anomalies reflect buried basaltic volcanic centers. Other, similar anomalies are identified as possible targets for further investigation. High-resolution gravity and ground-magnetic surveys, perhaps along with drilling sources of selected anomalies and radiometric age determinations, can provide valuable constraints in estimating potential volcanic hazard to the potential nuclear waste repository at Yucca Mountain.

  8. Hydrothermal waste package interactions with methane-containing basalt groundwater

    International Nuclear Information System (INIS)

    Hydrothermal waste package interaction tests with methane-containing synthetic basalt groundwater have shown that in the absence of gamma radiolysis, methane has little influence on the glass dissolution rate. Gamma radiolysis tests at fluxes of 5.5 x 105 and 4.4 x 104 R/hr showed that methane-saturated groundwater was more reducing than identical experiments where Ar was substituted for CH4. Dissolved methane, therefore, may be beneficial to the waste package in limiting the solubility of redox sensitive radionuclides such a 99Tc. Hydrocarbon polymers known to form under the irradiation conditions of these tests were not produced. The presence of the waste package constituents apparently inhibited the formation of the polymers, however, the mechanism which prevented their formation was not determined

  9. Geoscience parameter data base handbook: granites and basalts

    Energy Technology Data Exchange (ETDEWEB)

    1979-12-01

    The Department of Energy has the responsibility for selecting and constructing Federal repositories for radioactive waste. The Nuclear Regulatory Commission must license such repositories prior to construction. The basic requirement in the geologic disposal of radioactive waste is stated as: placement in a geologic host whereby the radioactive waste is not in mechanical, thermal or chemical equilibrium with the object of preventing physical or chemical migration of radionuclides into the biosphere or hydrosphere in hazardous concentration (USGS, 1977). The object of this report is to document the known geologic parameters of large granite and basalt occurrences in the coterminous United States, for future evaluation in the selection and licensing of radioactive waste repositories. The description of the characteristics of certain potential igneous hosts has been limited to existing data pertaining to the general geologic character, geomechanics, and hydrology of identified occurrences. A description of the geochemistry is the subject of a separate report.

  10. Interim reclamation report: Basalt Waste Isolation Project exploration shaft site

    International Nuclear Information System (INIS)

    In 1968, a program was started to assess the feasibility of storing Hanford Site defense waste in deep caverns constructed in basalt. This program was expanded in 1976 to include investigations of the Hanford Site as a potential location for a mined commercial nuclear waste repository. Extensive studies of the geotechnical aspects of the site were undertaken, including preparations for drilling a large diameter Exploratory Shaft. This report describes the development of the reclamation program for the Exploratory Shaft Facility, its implementation, and preliminary estimates of its success. The goal of the reclamation program is to return sites disturbed by the repository program as nearly as practicable to their original conditions using native plant species. 43 refs., 19 figs., 9 tabs

  11. Primitive off-rift basalts from Iceland and Jan Mayen

    DEFF Research Database (Denmark)

    Debaille, Vinciane; Trønnes, Reidar G.; Brandon, Alan D.;

    2009-01-01

    appear to be contaminated at a shallow level. The 187Os/188Os ratios in the remaining lavas with >30 ppt Os (n = 17) range between 0.12117 and 0.13324. These values are surprisingly low for oceanic island basalts and include some samples that are less than putative present-day primitive upper mantle (PUM...... with 187Os/188Os of 0.1296). These low 187Os/188Os preclude significant shallow-level contamination from oceanic crust. The 187Os/188Os ratios for Jan Mayen lavas are less than PUM, severely limiting the presence of any continental crust in their mantle source. A positive correlation between 143Nd/144...

  12. Shallow Plumbing Systems for Small-Volume Basaltic Volcanoes

    Science.gov (United States)

    Keating, G. N.; Valentine, G. A.; Krier, D. J.; Perry, F. V.

    2006-12-01

    We characterize the subvolcanic geometry of small-volume basaltic volcanoes (magmatic volatile-driven eruptions, 0.1 to 0.5 km3) based on a synthesis of field studies of 5 basaltic volcanoes with varying degrees of erosion exposing feeder dikes, conduits, and vent areas development of a complex conduit above ~50-70 m depth is reflected in bifurcating dikes and brecciation and stoping of the country rock. The overall zone of effect models, the width of the feeder dike from 250 to 500 m depth is expected to range from 1 to 10 m and is expected to decrease to about 1-2 meters below ~500 m. The flaring shape of the observed feeder systems is similar to results of theoretical modeling using lithostatic pressure- balanced flow conditions. Sizes of observed conduits differ from modeled dimensions by up to a factor of 10 in the shallow (100 m depth the difference is a factor of two to five. This difference is primarily due to the fact that observed eroded conduits record the superimposed effects of multiple eruptive events while theoretical model results define dimensions necessary for a single, steady eruption phase. The complex details of magma-host rock interactions observed at the study areas (contact welding, brecciation, bifurcating dikes and sills, and stoping) represent the mechanisms by which the lithostatic pressure-balanced geometry is attained. The similarity in the normalized shapes of theoretical and observed conduits demonstrates the appropriateness of the pressure-balanced modeling approach, validating the conclusions of Wilson and Head (1981) for this type of volcano.

  13. Repository site definition in basalt: Pasco Basin, Washington

    Energy Technology Data Exchange (ETDEWEB)

    Guzowski, R.V.; Nimick, F.B.; Muller, A.B.

    1982-03-01

    Discussion of the regional setting, geology, hydrology, and geochemistry of the Pasco Basin are included in this report. Pasco basin is a structural and topographic basin of approximately 2000 mi/sup 2/ (5180 km/sup 2/) located within the Yakima Fold Belt Subprovince of the Columbia Plateau. The stratigraphic sequence within the basin consists of an undetermined thickness of lower Miocene and younger flood basalts with interbedded and overlying sedimentary units. This sequence rests upon a basement of probably diverse rock types that may range in age from precambrian through early Tertiary. Although a large amount of information is available on the hydrology of the unconfined aquifer system, ground-water flow within the basin is, in general, poorly understood. Recharge areas for the Mabton interbed and the Saddle Mountains Formation are the highlands surrounding the basin with the flow for these units toward Gable Butte - Gable Mountain and Lake Wallula. Gable Butte - Gable Mountain probably is a ground-water sink, although the vertical flow direction in this zone is uncertain. The amount of upward vertical leakage from the Saddle Mountains Formation into the overlying sediments or to the Columbia River is unknown. Units underlying the Mabton interbed may have a flow scheme similar to those higher units or a flow scheme dominated by interbasin flow. Upward vertical leakage either throughout the basin, dominantly to the Columbia River, or dominantly to Lake Wallula has been proposed for the discharge of the lower units. None of these proposals is verified. The lateral and vertical distribution of major and minor ions in solution, Eh and pH, and ion exchange between basalt and ground-water are not well defined for the basin. Changes in the redox potential from the level of the subsurface facility to the higher stratigraphic levels along with the numerous other factors influencing K/sub d/, result in a poor understanding of the retardation process.

  14. Repository site definition in basalt: Pasco Basin, Washington

    International Nuclear Information System (INIS)

    Discussion of the regional setting, geology, hydrology, and geochemistry of the Pasco Basin are included in this report. Pasco basin is a structural and topographic basin of approximately 2000 mi2 (5180 km2) located within the Yakima Fold Belt Subprovince of the Columbia Plateau. The stratigraphic sequence within the basin consists of an undetermined thickness of lower Miocene and younger flood basalts with interbedded and overlying sedimentary units. This sequence rests upon a basement of probably diverse rock types that may range in age from precambrian through early Tertiary. Although a large amount of information is available on the hydrology of the unconfined aquifer system, ground-water flow within the basin is, in general, poorly understood. Recharge areas for the Mabton interbed and the Saddle Mountains Formation are the highlands surrounding the basin with the flow for these units toward Gable Butte - Gable Mountain and Lake Wallula. Gable Butte - Gable Mountain probably is a ground-water sink, although the vertical flow direction in this zone is uncertain. The amount of upward vertical leakage from the Saddle Mountains Formation into the overlying sediments or to the Columbia River is unknown. Units underlying the Mabton interbed may have a flow scheme similar to those higher units or a flow scheme dominated by interbasin flow. Upward vertical leakage either throughout the basin, dominantly to the Columbia River, or dominantly to Lake Wallula has been proposed for the discharge of the lower units. None of these proposals is verified. The lateral and vertical distribution of major and minor ions in solution, Eh and pH, and ion exchange between basalt and ground-water are not well defined for the basin. Changes in the redox potential from the level of the subsurface facility to the higher stratigraphic levels along with the numerous other factors influencing K/sub d/, result in a poor understanding of the retardation process

  15. High-Ti type N-MORB parentage of basalts from the south Andaman ophiolite suite, India

    Indian Academy of Sciences (India)

    Rajesh K Srivastava; R Chandra; Anant Shastry

    2004-12-01

    A complete dismembered sequence of ophiolite is well exposed in the south Andaman region that mainly comprises ultramafic cumulates, serpentinite mafic plutonic and dyke rocks, pillow lava, radiolarian chert, and plagiogranite. Pillow lavas of basaltic composition occupy a major part of the Andaman ophiolite suite (AOS). These basalts are well exposed all along the east coast of southern part of the south AOS. Although these basalts are altered due to low-grade metamorphism and late hydrothermal processes, their igneous textures are still preserved. These basalts are mostly either aphyric or phyric in nature. Aphyric type exhibits intersertal or variolitic textures, whereas phyric variety shows porphyritic or sub-ophitic textures. The content of alkalies and silica classify these basalts as sub-alkaline basalts and alkaline basalts. A few samples show basaltic andesite, trachybasalt, or basanitic chemical composition. High-field strength element (HFSE) geochemistry suggests that studied basalt samples are probably derived from similar parental magmas. Al2O3/TiO2 and CaO/TiO2 ratios classify these basalts as high-Ti type basalt. On the basis of these ratios and many discriminant functions and diagrams, it is suggested that the studied basalts, associated with Andaman ophiolite suite, were derived from magma similar to N-MORB and emplaced in the mid-oceanic ridge tectonic setting.

  16. A mantle plume beneath California? The mid-Miocene Lovejoy Flood Basalt, northern California

    Science.gov (United States)

    Garrison, N.J.; Busby, C.J.; Gans, P.B.; Putirka, K.; Wagner, D.L.

    2008-01-01

    The Lovejoy basalt represents the largest eruptive unit identified in California, and its age, volume, and chemistry indicate a genetic affinity with the Columbia River Basalt Group and its associated mantle-plume activity. Recent field mapping, geochemical analyses, and radiometric dating suggest that the Lovejoy basalt erupted during the mid-Miocene from a fissure at Thompson Peak, south of Susanville, California. The Lovejoy flowed through a paleovalley across the northern end of the Sierra Nevada to the Sacramento Valley, a distance of 240 km. Approximately 150 km3 of basalt were erupted over a span of only a few centuries. Our age dates for the Lovejoy basalt cluster are near 15.4 Ma and suggest that it is coeval with the 16.1-15.0 Ma Imnaha and Grande Ronde flows of the Columbia River Basalt Group. Our new mapping and age dating support the interpretation that the Lovejoy basalt erupted in a forearc position relative to the ancestral Cascades arc, in contrast with the Columbia River Basalt Group, which erupted in a backarc position. The arc front shifted trenchward into the Sierran block after 15.4 Ma. However, the Lovejoy basalt appears to be unrelated to volcanism of the predominantly calc-alkaline Cascade arc; instead, the Lovejoy is broadly tholeiitic, with trace-element characteristics similar to the Columbia River Basalt Group. Association of the Lovejoy basalt with mid-Miocene flood basalt volcanism has considerable implications for North American plume dynamics and strengthens the thermal "point source" explanation, as provided by the mantle-plume hypothesis. Alternatives to the plume hypothesis usually call upon lithosphere-scale cracks to control magmatic migrations in the Yellowstone-Columbia River basalt region. However, it is difficult to imagine a lithosphere-scale flaw that crosses Precambrian basement and accreted terranes to reach the Sierra microplate, where the Lovejoy is located. Therefore, we propose that the Lovejoy represents a rapid

  17. Probability encoding of hydrologic parameters for basalt. Elicitation of expert opinions from a panel of three basalt waste isolation project staff hydrologists

    International Nuclear Information System (INIS)

    The present study implemented a probability encoding method to estimate the probability distributions of selected hydrologic variables for the Cohassett basalt flow top and flow interior, and the anisotropy ratio of the interior of the Cohassett basalt flow beneath the Hanford Site. Site-speciic data for these hydrologic parameters are currently inadequate for the purpose of preliminary assessment of candidate repository performance. However, this information is required to complete preliminary performance assessment studies. Rockwell chose a probability encoding method developed by SRI International to generate credible and auditable estimates of the probability distributions of effective porosity and hydraulic conductivity anisotropy. The results indicate significant differences of opinion among the experts. This was especially true of the values of the effective porosity of the Cohassett basalt flow interior for which estimates differ by more than five orders of magnitude. The experts are in greater agreement about the values of effective porosity of the Cohassett basalt flow top; their estimates for this variable are generally within one to two orders of magnitiude of each other. For anisotropy ratio, the expert estimates are generally within two or three orders of magnitude of each other. Based on this study, the Rockwell hydrologists estimate the effective porosity of the Cohassett basalt flow top to be generally higher than do the independent experts. For the effective porosity of the Cohassett basalt flow top, the estimates of the Rockwell hydrologists indicate a smaller uncertainty than do the estimates of the independent experts. On the other hand, for the effective porosity and anisotropy ratio of the Cohassett basalt flow interior, the estimates of the Rockwell hydrologists indicate a larger uncertainty than do the estimates of the independent experts

  18. Probability encoding of hydrologic parameters for basalt. Elicitation of expert opinions from a panel of three basalt waste isolation project staff hydrologists

    Energy Technology Data Exchange (ETDEWEB)

    Runchal, A.K.; Merkhofer, M.W.; Olmsted, E.; Davis, J.D.

    1984-11-01

    The present study implemented a probability encoding method to estimate the probability distributions of selected hydrologic variables for the Cohassett basalt flow top and flow interior, and the anisotropy ratio of the interior of the Cohassett basalt flow beneath the Hanford Site. Site-speciic data for these hydrologic parameters are currently inadequate for the purpose of preliminary assessment of candidate repository performance. However, this information is required to complete preliminary performance assessment studies. Rockwell chose a probability encoding method developed by SRI International to generate credible and auditable estimates of the probability distributions of effective porosity and hydraulic conductivity anisotropy. The results indicate significant differences of opinion among the experts. This was especially true of the values of the effective porosity of the Cohassett basalt flow interior for which estimates differ by more than five orders of magnitude. The experts are in greater agreement about the values of effective porosity of the Cohassett basalt flow top; their estimates for this variable are generally within one to two orders of magnitiude of each other. For anisotropy ratio, the expert estimates are generally within two or three orders of magnitude of each other. Based on this study, the Rockwell hydrologists estimate the effective porosity of the Cohassett basalt flow top to be generally higher than do the independent experts. For the effective porosity of the Cohassett basalt flow top, the estimates of the Rockwell hydrologists indicate a smaller uncertainty than do the estimates of the independent experts. On the other hand, for the effective porosity and anisotropy ratio of the Cohassett basalt flow interior, the estimates of the Rockwell hydrologists indicate a larger uncertainty than do the estimates of the independent experts.

  19. Petrochemistry and origin of basalt breccia from Ban Sap Sawat area, Wichian Buri, Phetchabun, central Thailand

    Directory of Open Access Journals (Sweden)

    Phisit Limtrakun

    2013-08-01

    Full Text Available Thailand is usually considered to be controlled by escape tectonics associated with India-Asia collision during theLate Cenozoic, and basaltic volcanism took place in this extensional period. This volcanism generated both subaqueous andsubaerial lava flows with tholeiitic to alkalic basaltic magma. The subaqueous eruptions represented by the studied WichianBuri basalts, Ban Sap Sawat in particular, are constituted by two main types of volcanic lithofacies, including lava flows andbasalt breccias. The lava flows are commonly porphyritic with olivine and plagioclase phenocrysts and microphenocrysts,and are uncommonly seriate textured. The basalt breccias are strongly vitrophyric texture with olivine and plagioclasephenocrysts and microphenocrysts. Chemical analyses indicate that both lava flows and basalt breccias have similar geochemical compositions, signifying that they were solidified from the same magma. Their chondrite normalized REE patternsand N-MORB normalized patterns are closely analogous to the Early to Middle Miocene tholeiites from central Sinkhote-Alinand Sakhalin, northeastern margin of the Eurasian continent which were erupted in a continental rift environment. The originfor the Wichian Buri basalts show similarity of lava flows and basalt breccias, in terms of petrography and chemical compositions, signifying that they have been formed from the same continental within-plate, transitional tholeiitic magma.

  20. Extreme Mantle Heterogeneity beneath the Jingpohu Area, Northeastern China-Geochemical Evidence of Holocene Basaltic Rock

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Holocene basaltic rocks of the Jingpohu area are located in the "Crater Forest" and Hamatang districts to the northwest of the Jingpohu Lake. Although there is only a distance of 15 km between the two districts, their petrological characteristics are very different: alkaline olivine basalt without any megacrysts in the former, and leucite tephrite with Ti-amphibole, phlogopite and anorthoclasite megacrysts in the latter. On the basis of their geochemical characteristics, the two types of basaltic rocks should belong to weakly sodian alkaline basalts. But leucite tephrite is characterized by higher Al2O3, Na2O and K2O, higher enrichment in light rare earth elements (LREE) and large ion lithophile elements (LILE), lower MgO and CaO, compatible elements and moderately compatible elements and lower Mg# values and Na/K ratios in comparison with alkaline olivine basalt. However, the two types of basaltic rocks have similar Sr, Nd, Pb isotopic compositions, which suggests that the mantle beneath the Jingpohu area was homogeneous before undergoing some geological processes about 3490 years ago. As the activity of the mantle plume led to different degrees of metasomatism, extreme mantle source heterogeneities occurred beneath the Jingpohu area. In comparison with alkaline olivine basalt, the leucite tephrite was derived from the more enriched mantle source region and resulted from strong metasomatism.

  1. Origin of low δ26Mg Cenozoic basalts from South China Block and their geodynamic implications

    Science.gov (United States)

    Huang, Jian; Li, Shu-Guang; Xiao, Yilin; Ke, Shan; Li, Wang-Ye; Tian, Ye

    2015-09-01

    Origin of low δ26Mg basalts is a controversial subject and has been attributed to interaction of isotopically light carbonatitic melts derived from a subducted oceanic slab with the mantle (Yang et al., 2012), or alternatively, to accumulation of isotopically light ilmenite (FeTiO3) in their mantle source (Sedaghatpour et al., 2013). To study the origin of low δ26Mg basalts and evaluate whether Mg isotope ratios of basalts can be used to trace deeply recycled carbon, high-precision major and trace element and Mg isotopic analyses on the Cenozoic alkaline and tholeiitic basalts from the South China Block (SCB), eastern China have been carried out in this study. The basalts show light Mg isotopic compositions, with δ26Mg ranging from -0.60 to -0.35. The relatively low TiO2 contents (eclogite transformed from carbonate-bearing oceanic crust during plate subduction. As only the Pacific slab has an influence on both the North China Block (NCB) and SCB, our results together with the study of Yang et al. (2012) demonstrate that the recycled carbonatitic melts might have originated from the stagnant Pacific slab beneath East Asia in the Cretaceous and Cenozoic and that a widespread carbonated upper mantle exists beneath eastern China, which may serve as the main source for the <110 Ma basalts in this area. Thus, our study demonstrates that Mg isotope ratios of basalts are a powerful tool to trace deeply recycled carbon.

  2. Isotopic composition of lead in oceanic basalt and its implication to mantle evolution

    International Nuclear Information System (INIS)

    New data are given in this report for (1) Pb isotopic compositions and U, Th, and Pb concentrations of basalts from the island of Hawaii: (2) redetermined Pb isotopic compositions of some abyssal tholeiites; and (3) U, Th, and Pb concentrations of altered and fresh abyssal basalts, and basalt genesis and mantle evolution are discussed. The Th/U ratios of abyssal and Japanese tholeiites are distinctly lower than those of tholeiites and alkali basalts from other areas. It is thought that these low values reflect a part of the mantle depleted in large ionic lithophile elements. Thus a mantle evolution model is presented, in which Th/U ratios of the depleted zone in the mantle have decreased to approximately 2, and U/Pb ratios have increased, showing an apparent approximately 1.5-b.y. isochron trend in the 207Pb/204Pb vs. 206Pb/204Pb plot. The Pb isotopic compositions of basalts from the island of Hawaii are distinct for each of the five volcanoes, and within each volcano, Pb's of tholeiites and alkali basalts are similar. An interaction between partially melted material (hot plume) of the asthenosphere and the lithosphere is suggested to explain the trend in the Pb isotopic compositions of Hawaiian basalts. (Auth.)

  3. Public Access to Digital Material; A Call to Researchers: Digital Libraries Need Collaboration across Disciplines; Greenstone: Open-Source Digital Library Software; Retrieval Issues for the Colorado Digitization Project's Heritage Database; Report on the 5th European Conference on Digital Libraries, ECDL 2001; Report on the First Joint Conference on Digital Libraries.

    Science.gov (United States)

    Kahle, Brewster; Prelinger, Rick; Jackson, Mary E.; Boyack, Kevin W.; Wylie, Brian N.; Davidson, George S.; Witten, Ian H.; Bainbridge, David; Boddie, Stefan J.; Garrison, William A.; Cunningham, Sally Jo; Borgman, Christine L.; Hessel, Heather

    2001-01-01

    These six articles discuss various issues relating to digital libraries. Highlights include public access to digital materials; intellectual property concerns; the need for collaboration across disciplines; Greenstone software for construction and presentation of digital information collections; the Colorado Digitization Project; and conferences…

  4. Basalt generation at the Apollo 12 site. Part 2: Source heterogeneity, multiple melts, and crustal contamination

    Science.gov (United States)

    Neal, Clive R.; Hacker, Matthew D.; Snyder, Gregory A.; Taylor, Lawrence A.; Liu, Yun-Gang; Schmitt, Roman A.

    1994-01-01

    The petrogenesis of Apollo 12 mare basalts has been examined with emphasis on trace-element ratios and abundances. Vitrophyric basalts were used as parental compositions for the modeling, and proportions of fractionating phases were determined using the MAGFOX prograqm of Longhi (1991). Crystal fractionation processes within crustal and sub-crustal magma chambers are evaluated as a function of pressure. Knowledge of the fractionating phases allows trace-element variations to be considered as either source related or as a product of post-magma-generation processes. For the ilmenite and olivine basalts, trace-element variations are inherited from the source, but the pigeonite basalt data have been interpreted with open-system evolution processes through crustal assimilation. Three groups of basalts have been examined: (1) Pigeonite basalts-produced by the assimilation of lunar crustal material by a parental melt (up to 3% assimilation and 10% crystal fractionation, with an 'r' value of 0.3). (2) Ilmenite basalts-produced by variable degrees of partial melting (4-8%) of a source of olivine, pigeonite, augite, and plagioclase, brought together by overturn of the Lunar Magma Ocean (LMO) cumulate pile. After generation, which did not exhaust any of the minerals in the source, these melts experienced closed-system crystal fractionation/accumulation. (3) Olivine basalts-produced by variable degrees of partial melting (5-10%) of a source of olivine, pigeonite, and augite. After generation, again without exhausting any of the minerals in the source, these melts evolved through crystal accumulation. The evolved liquid counterparts of these cumulates have not been sampled. The source compositions for the ilmenite and olivine basalts were calculated by assuming that the vitrophyric compositions were primary and the magmas were produced by non-modal batch melting. Although the magnitude is unclear, evaluation of these source regions indicates that both be composed of early- and

  5. Ensialic tectonic setting of the archaean Rio das Velhas greenstone belt: Nd and Pb isotopic evidence from the Bonfim metamorphic complex, Quadrilatero Ferrifero, Brazil

    International Nuclear Information System (INIS)

    The Bonfim Metamorphic Complex is one of the sialic fragments that make up the Archaen crust of the Southern Sao Francisco Craton, eastern Brazil. The northern part of the Bonfim Metamorphic Complex, located in the Quadrilatero Ferrifero region, was investigated on the basis of petrology, geochemistry and U-Pb and Sm-Nd geochronology. This complex comprises eight lithostratigraphic units, six of them Neo Archaen in age, composed of trondhjemitic to granitic gneisses, intrusive granitoids and and amphibolites. The other two units are Mesoproterozoic and probably Phanerozoic mafic dikes. The origin of rock protoliths of the Bonfim Metamorphic Complex goes back to the 3200 Ma ago, as suggested by inherited U-Pb age components and Sm-Nd (TDM) crus formation ages. The main evolution of the Northern Bonfim Metamorphic Complex was associated with the Rio das Velhas Tectonothermal Event (2780 - 2700 Ma) that correlates with major Neo Archean events in the Southern Sao Francisco Craton. The Rio das Velhas event, in the Northern Bonfim Metamorphic Complex, is characteriszed by widespread metamorphism, calc-alkaline (tonalite bodies) and tholeitic magmatism within both the sialic crust and Rio das Velhas greenstone belt. The geological features together with geochemical signatures suggest a convergent margin setting for the Neoproterozoic evolution, which final steps are represented by an intrusive granite activity dated by U-Pb zircon at 2703± 24/20 Ma. During the proterozoic, the Neo-Archaen crust was affected by thermotectonic overprints, under low-grade facies metamorphic conditions, as suggested by resetting of the Rb-Sr (whole rock), and K-Ar (mineral) isotopic systems. Finally, from the petrological, geochemical and geochronological data, this paper presents a global tectonic model for the geological evolution from the Meso-to Neo Archaen in the Quadrilatero Ferrifero region. This model comprises the following geological setting and processes: active margins, mantelic

  6. Tracing sources of crustal contamination using multiple S and Fe isotopes in the Hart komatiite-associated Ni-Cu-PGE sulfide deposit, Abitibi greenstone belt, Ontario, Canada

    Science.gov (United States)

    Hiebert, R. S.; Bekker, A.; Houlé, M. G.; Wing, B. A.; Rouxel, O. J.

    2016-03-01

    Assimilation by mafic to ultramafic magmas of sulfur-bearing country rocks is considered an important contributing factor to reach sulfide saturation and form magmatic Ni-Cu-platinum group element (PGE) sulfide deposits. Sulfur-bearing sedimentary rocks in the Archean are generally characterized by mass-independent fractionation of sulfur isotopes that is a result of atmospheric photochemical reactions, which produces isotopically distinct pools of sulfur. Likewise, low-temperature processing of iron, through biological and abiotic redox cycling, produces a range of Fe isotope values in Archean sedimentary rocks that is distinct from the range of the mantle and magmatic Fe isotope values. Both of these signals can be used to identify potential country rock assimilants and their contribution to magmatic sulfide deposits. We use multiple S and Fe isotopes to characterize the composition of the potential iron and sulfur sources for the sulfide liquids that formed the Hart deposit in the Shaw Dome area within the Abitibi greenstone belt in Ontario (Canada). The Hart deposit is composed of two zones with komatiite-associated Ni-Cu-PGE mineralization; the main zone consists of a massive sulfide deposit at the base of the basal flow in the komatiite sequence, whereas the eastern extension consists of a semi-massive sulfide zone located 12 to 25 m above the base of the second flow in the komatiite sequence. Low δ56Fe values and non-zero δ34S and Δ33S values of the komatiitic rocks and associated mineralization at the Hart deposit is best explained by mixing and isotope exchange with crustal materials, such as exhalite and graphitic argillite, rather than intrinsic fractionation within the komatiite. This approach allows tracing the extent of crustal contamination away from the deposit and the degree of mixing between the sulfide and komatiite melts. The exhalite and graphitic argillite were the dominant contaminants for the main zone of mineralization and the eastern

  7. Experimental Study on Unconfined Compressive Strength of Basalt Fiber Reinforced Clay Soil

    OpenAIRE

    Lei Gao; Guohui Hu; Nan Xu; Junyi Fu; Chao Xiang; Chen Yang

    2015-01-01

    In order to study the mechanism and effect of basalt fiber reinforced clay soil, a series of unconfined compressive strength tests conducted on clay soil reinforced with basalt fiber have been performed under the condition of optimum water content and maximum dry density. Both the content and length of basalt fiber are considered in this paper. When the effect of content is studied, the 12 mm long fibers are dispersed into clay soil at different contents of 0.05%, 0.1%, 0.15%, 0.20%, 0.25%, 0...

  8. Thicknesses and Volumes of Lunar Mare Basalt Flow Units

    Science.gov (United States)

    Hiesinger, H.; Head, J. W.; Wolf, U.; Jaumann, R.; Neukum, G.

    Reliable estimates of the flow thickness are crucial to our understanding of the vol- umes and the flux of lunar mare basalt volcanism. Previous work on basalt flow unit thicknesses was based on (1) shadow measurements in high-resolution images that were taken under low-sun conditions, (2) in situ observations, e.g. of Hadley Rille at the Apollo 15 landing site, and (3) on studies of the chemical kinetic aspects of lava emplacement and cooling. These studies revealed flow unit thicknesses between 1 and 96 m. Flow unit thicknesses derived from imaging data are on average ~21 m, in contrast to chemical kinetic considerations that yield thicknesses of less than 10 m. We used crater size-distribution measurements to estimate flow unit thicknesses. A large number (~60) of our crater counts show evidence for resurfacing events and these "irregularities" in the crater size distributions are used to infer the thickness of the resurfacing layer, that is the thickness of lava flows in several nearside basins. We find that the average minimum flow unit height of all investigated units is on the order of 34 m (+7/-6 m) and that the average maximum flow unit height is about 53 m (+9/- 9 m). On average the thinnest flow units were detected for units in Mare Insularum, Mare Cognitum, and Mare Nubium, thickest flows are exposed in Mare Tranquilli- tatis and Mare Humorum. Average thicknesses of flow units in Oceanus Procellarum and Mare Imbrium are slightly larger than in Mare Insularum, Mare Cognitum, and Mare Nubium, but are smaller than in Mare Tranquillitatis and Mare Humorum. The minimum average volume of all investigated flow units is~590 km3 and the maximum average volume is~940 km3. Our data indicate that the most voluminous flow units are located in Mare Humorum and Mare Tranquillitatis. As crater counts for units in Mare Serenitatis do not exhibit prominent deflections we conclude that these units have not to been resurfaced with flows thick enough to be detected in the

  9. Circumventing shallow air contamination in Mid Ocean Ridge Basalts

    Science.gov (United States)

    Mukhopadhyay, Sujoy; Parai, Rita; Tucker, Jonathan; Middleton, Jennifer; Langmuir, Charles

    2016-04-01

    Noble gases in mantle-derived basalts provide a rich portrait of mantle degassing and surface-interior volatile exchange. However, the ubiquity of shallow-level air contamination frequently obscures the mantle noble gas signal. In a majority of samples, shallow air contamination dominates the noble gas budget. As a result, reconstructing the variability in heavy noble gas mantle source compositions and inferring the history of deep recycling of atmospheric noble gases is difficult. For example, in the gas-rich popping rock 2ΠD43, 129Xe/130Xe ratios reach 7.7±0.23 in individual step-crushes, but the bulk composition of the sample is close to air (129Xe/130Xe of 6.7). Here, we present results from experiments designed to elucidate the source of shallow air contamination in MORBs. Step-crushes were carried out to measure He, Ne, Ar and Xe isotopic compositions on two aliquots of a depleted popping glass that was dredged from between the Kane and Atlantis Fracture Zones of the Mid-Atlantic Ridge in May 2012. One aliquot was sealed in ultrapure N2 after dredge retrieval, while the other aliquot was left exposed to air for 3.5 years. The bulk 20Ne/22Ne and 129Xe/130Xe ratios measured in the aliquot bottled in ultrapure N2 are 12.3 and 7.6, respectively, and are nearly identical to the estimated mantle source values. On the other hand, step crushes in the aliquot left exposed to air for several years show Ne isotopic compositions that are shifted towards air, with a bulk 20Ne/22Ne of 11.5; the bulk 129Xe/130Xe, however, was close to 7.6. These results indicate that lighter noble gases exchange more efficiently between the bubbles trapped in basalt glass and air, suggesting a diffusive or kinetic mechanism for the incorporation of the shallow air contamination. Importantly, in Ne-Ar or Ar-Xe space, step-crushes from the bottled aliquot display a trend that can be easily fit with a simple two-component hyperbolic mixing between mantle and atmosphere noble gases. Step

  10. Mineralogy, Petrology and Oxygen Fugacity of the LaPaz Icefield Lunar Basaltic Meteorites and the Origin of Evolved Lunar Basalts

    Science.gov (United States)

    Collins, S. J.; Righter, K.; Brandon, A. D.

    2005-01-01

    LAP 02205 is a 1.2 kg lunar mare basalt meteorite found in the Lap Paz ice field of Antarctica in 2002 [1]. Four similar meteorites were also found within the same region [1] and all five have a combined mass of 1.9 kg (LAP 02224, LAP 02226, LAP 02436 and LAP 03632, hereafter called the LAP meteorites). The LAP meteorites all contain a similar texture, mineral assemblage, and composition. A lunar origin for these samples comes from O isotopic data for LAP 02205 [1], Fe/Mn ratios of pyroxenes [1-5], and the presence of distinct lunar mineralogy such as Fe metal and baddeleyite. The LAP meteorites may represent an area of the Moon, which has never been sampled by Apollo missions, or by other lunar meteorites. The data from this study will be used to compare the LAP meteorites to Apollo mare basalts and lunar basaltic meteorites, and will ultimately help to constrain their origin.

  11. Enhancement of interfacial properties of basalt fiber reinforced nylon 6 matrix composites with silane coupling agents

    Directory of Open Access Journals (Sweden)

    2010-10-01

    Full Text Available In this work solution surface treatment was applied for producing basalt fiber reinforced PA6 matrix composites. Beyond scanning electron microscopy, static and dynamic mechanical tests, dynamic mechanical analysis of composites was used for qualifying the interfacial adhesion in a wide temperature range. The loss factor peak height of loss factor is particularly important, because it is in close relationship with the mobility of polymer molecular chain segments and side groups, hence it correlates with the number and strength of primary or secondary bondings established between the matrix and the basalt fibers. It was proven, that the interfacial adhesion between basalt fibers and polyamide can be largely improved by the application of silane coupling agents in the entire usage temperature range of composites. The presence of coupling agents on the surface of basalt fibers was proven by Fourier transform infrared spectroscopy. The best results were obtained by 3-glycidoxypropyltrimethoxysilane coupling agent.

  12. Age and petrology of the Kalaupapa Basalt, Molokai, Hawaii ( geochemistry, Sr isotopes).

    Science.gov (United States)

    Clague, D.A.

    1982-01-01

    The post-erosional Kalaupapa Basalt on East Molokai, Hawaii, erupted between 0.34 and 0.57 million years ago to form the Kalaupapa Peninsula. The Kalaupapa Basalt ranges in composition from basanite to lava transitional between alkalic and tholeiitic basalt. Rare-earth and other trace-element abundances suggest that the Kalaupapa Basalt could be generated by 11-17% partial melting of a light-REE-enriched source like that from which the post-erosional lavas of the Honolulu Group on Oahu were generated by 2-11% melting. The 87Sr/86Sr ratios of the lavas range from 0.70320 to 0.70332, suggesting that the variation in composition mainly reflects variation in the melting process rather than heterogeneity of sources. The length of the period of volcanic quiescence that preceded eruption of post-erosional lavas in the Hawaiian Islands decreased as volcanism progressed from Kauai toward Kilauea. - Authors

  13. In-situ stress measurement in a jointed basalt: the suitability of five overcoring techniques

    International Nuclear Information System (INIS)

    Overcoring tests were conducted at the Near-Surface Test Facility (NSTF) to assess the suitability of five techniques (US Bureau of Mines borehole deformation gauge (BDG), Commonwealth Scientific and Industrial Research Organization (CSIRO) hollow inclusion stress cell, epoxy inclusion, Lulea triaxial gauge (LuH gauge), and Council for Scientific and Industrial Research (CSIR) doorstopper) for in situ stress determination in a closely jointed basalt. This effort is in support of the Basalt Waste Isolation project, which is studying the feasibility of locating a nuclear waste repository in the basalts of the Hanford Site in southeastern Washington. This paper preents the results from the overcoring study that formed the basis for selection of two techniques to be used during the further exploration of the basalt formations at depth

  14. Mechanical Properties of Wood Flour Reinforced High Density Polyethylene Composites with Basalt Fibers

    Directory of Open Access Journals (Sweden)

    Guojun LU

    2014-12-01

    Full Text Available Basalt fibers (BFs were surface-treated with a vinyl triethoxy silane coupling agent to improve the mechanical properties of wood fiber-reinforced high density polyethylene (HDPE composites. Basalt fibers were characterized with SEM and FT-IR. The effects of the basalt fiber content and apparent morphology on the mechanical properties of the hybrid composites were investigated in this paper. The results show that the BF coated with the vinyl triethoxy silane coupling agent resulted in an improvement in mechanical properties due to the increased interfacial compatibility between the BF and HDPE. The flexural strength and impact properties significantly increased with 4 wt.% modified basalt fibers. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6441

  15. Combined Thickness of the Modeled Saddle Mountains Basalt and Mabton Interbed Geomodel Units (smthk_f)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The smthk_f grid represents the modeled combined thickness of the Saddle Mountains Basalt and Mabton interbed geomodel units at a 500 foot resolution. It is one...

  16. Mare Basalt Volcanism: Generation, Ascent, Eruption, and History of Emplacement of Secondary Crust on the Moon

    Science.gov (United States)

    Head, J. W.; Wilson, L.

    2016-05-01

    Theoretical analyses of the generation, ascent, intrusion and eruption of basaltic magma provides new insight into magma source depths, supply processes, transport and emplacement mechanisms (dike intrusions, effusive and explosive eruptions).

  17. INVESTIGATION OF SOFTENING AGENT PREPARATION AND PERFORMANCE OF HANDMADE ECOCOMPOSITES WITH CONIFEROUS WOOD AND BASALT FIBERS

    Institute of Scientific and Technical Information of China (English)

    GuangjianWang; DekuShang; KailiangZhang; LinnaHu; ZhenhuaGuo

    2004-01-01

    In this investigation, basalt mineral fiber softening agent was prepared in order to obtain desirable flexible performance. Stability and physical chemistry natures of softening agent were evaluated by particle size distribution, dilution, storage and folding endurance etc. Constitutes of basalt and wood fibers were determined by energy dispersion analysis X-ray which served as an accessory of scanning electron microscopy (SEM-EDAX). Naturally degradable ecocomposite was prepared by basalt and wood fibers. The results of SEM observation illustrated that the wood and basalt fibers were blended uniformly. The impact factors of beating degree, content of wood fibers and adhesive etc. were discussed. The structure of the naturally degradable ecocomposite was contrasted with that of pure wood fibers and the cause of excellent filtration performance was analyzed. Compared with traditional methods, it was of saving wood resource, a large amount of water and reducing second pollution. As a consequence, the ecocomposite harmonized with environment and accorded with requirement of benignly friendly environment.

  18. D-Poor Hydrogen in Lunar Mare Basalts Assimilated from Lunar Regolith

    Science.gov (United States)

    Treiman, A. H.; Boyce, J. W.; Greenwood, J. P.; Eiler, J. M.; Gross, J.; Guan, Y.; Ma, C.; Stolper, E. M.

    2016-05-01

    D/H in apatites in mare basalts decreases with Fe-Mg homogenization of their pyroxenes. This suggests that the low D/H represents hydrogen from lunar regolith, which masquerading as an igneous component.

  19. Basaltic magmatism on the Moon. A perspective from volcanic picritic glasses

    Science.gov (United States)

    Shearer, C. K.; Papike, J. J.

    1993-01-01

    It is widely accepted that basaltic magmas are products of partial fusion of peridotite within planetary mantles. As such they provide valuable insights into the structure and processes of planetary interiors. Those compositions which approach primary melt compositions provide both a clearer vision of planetary interiors and a starting point at which to understand basaltic evolution. Within the collection of lunar samples returned by the Apollo and Luna missions are homogeneous, picritic glass beads of volcanic origin. These glass beads provide a unique perspective concerning the origin of mare basalts, the characteristics of the lunar interior, and processes culminating in the early differentiation of the moon. In this presentation, we report our ion microprobe derived trace element data from all picritic glasses previously identified. We place this trace element data and literature isotopic and experimental data on the picritic glasses with the framework of mare basaltic magmatism.

  20. Where did Anomalous Basaltic Meteorites get Their Oxygen Anomaly? The Case of Bunburra Rockhole

    Science.gov (United States)

    Benedix, G. K.; Bland, P. A.; Greenwood, R. C.; Franchi, I. A.; Friedrich, J. M.; Towner, M. C.

    2013-09-01

    A number of eucrite-like basaltic meteorites have been identified that have oxygen isotopic compositions which plot away from the main HED mass fractionation line. We are exploring some options to explain this with data from Bunburra Rockhole.

  1. Off-gassing induced tracer release from molten basalt pools

    International Nuclear Information System (INIS)

    Two in situ vitrification (ISV) field tests were conducted at the Idaho National Engineering Laboratory (INEL) during the summer of 1990 to assess ISV suitability for long-term stabilization of buried waste that contains transuranic and other radionuclide contaminants. The ISV process uses electrical resistance heating to melt buried waste and soil in place, which upon cooldown and resolidification fixes the waste into a vitrified (glass-like) form. In these two ISV field tests, small quantities of rare-earth oxides (tracers DY2O3, Yb2O3, and Tb4O7) were placed in the test pits to simulate the presence of plutonium oxides and assess plutonium retention/release behavior. The analysis presented in this report indicates that dissolution of tracer oxides into basaltic melts can be expected with subsequent tracer molecular or microparticle carry-off by escaping gas bubbles, which is similar to adsorptive bubble separation and ion flotation processes employed in the chemical industry to separate dilute heavy species from liquids under gas sparging conditions. Gaseous bubble escape from the melt surface and associated aerosolization is believed to be responsible for small quantities of tracer ejection from the melt surface to the cover hood and off-gas collection system. Methods of controlling off-gassing during ISV would be expected to improve the overall retention of such heavy oxide contaminants during melting/vitrification of buried waste

  2. Monitoring and sampling perched ground water in a basaltic terrain

    International Nuclear Information System (INIS)

    Perched ground water zones are often overlooked in monitoring plans, but they can provide significant information on water and contaminant movement. This paper presents information about perched ground water obtained from drilling and monitoring at a hazardous and radioactive waste disposal site at the Idaho National Engineering Laboratory. Six of forty-five wells drilled at the Radioactive Waste Management Complex have detected perched water in basalts above sedimentary interbeds. Perched water has been detected at depths of 90 and 210 ft below land surface, approximately 370 ft above the regional water table. Eighteen years of water level measurements from one well at a depth of 210 ft indicate a consistent source of water. Water level data indicate a seasonal fluctuation. The maximum water level in this well varies within a 0.5 ft interval, suggesting the water level reaches equilibrium with the inflow to the well at this height. Volatile organic constituents have been detected in concentrations from 1.2 to 1.4 mg/L of carbon tetrachloride. Eight other volatile organics have been detected. The concentrations of organics are consistent with the prevailing theory of movement by diffusion in the gaseous phase. Results of tritium analyses indicate water has moved to a depth of 86 ft in 17 yr. Results of well sampling analyses indicate monitoring and sampling of perched water can be a valuable resource for understanding the hydrogeologic environment of the vadose zone at disposal sites

  3. Possible solar noble-gas component in Hawaiian basalts

    Science.gov (United States)

    Honda, M.; McDougall, I.; Patterson, D.B.; Doulgeris, A.; Clague, D.A.

    1991-01-01

    THE noble-gas elemental and isotopic composition in the Earth is significantly different from that of the present atmosphere, and provides an important clue to the origin and history of the Earth and its atmosphere. Possible candidates for the noble-gas composition of the primordial Earth include a solar-like component, a planetary-like component (as observed in primitive meteorites) and a component similar in composition to the present atmosphere. In an attempt to identify the contributions of such components, we have measured isotope ratios of helium and neon in fresh basaltic glasses dredged from Loihi seamount and the East Rift Zone of Kilauea1-3. We find a systematic enrichment in 20Ne and 21Ne relative to 22Ne, compared with atmospheric neon. The helium and neon isotope signatures observed in our samples can be explained by mixing of solar, present atmospheric, radiogenic and nucleogenic components. These data suggest that the noble-gas isotopic composition of the mantle source of the Hawaiian plume is different from that of the present atmosphere, and that it includes a significant solar-like component. We infer that this component was acquired during the formation of the Earth.

  4. Possible solar noble-gas component in Hawaiian basalts

    International Nuclear Information System (INIS)

    The noble-gas elemental and isotopic composition in the Earth is significantly different from that of the present atmosphere, and provides an important clue to the origin and history of the Earth and its atmosphere. Possible candidates for the noble-gas composition of the primordial Earth include a solar-like component, a planetary-like component (as observed in primitive meteorites) and a component similar in composition to the present atmosphere. In an attempt to identify the contributions of such components, we have measured isotope ratios of helium and neon in fresh basaltic glasses dredged from Loihi seamount and the East Rift Zone of Kilauea. We find a systematic enrichment in 20Ne and 21Ne relative to 22Ne, compared with atmospheric neon. The helium and neon isotope signatures observed in our samples can be explained by mixing of solar, present atmospheric, radiogenic and nucleogenic components. These data suggest that the noble-gas isotopic composition of the mantle source of the Hawaiian plume is different from that of the present atmosphere, and that it includes a significant solar-like component. We infer that this component was acquired during the formation of the Earth. (author)

  5. Underground engineering at the Basalt Waste Isolation Project

    International Nuclear Information System (INIS)

    A special task group was organized by the US National Committee for Rock Mechanics and the Board on Radioactive Waste Management of the National Research Council to address issues relating to the geotechnical site characterization program for an underground facility to house high-level radioactive waste of the Basalt Waste Isolation Project (BWIP). Intended to provide an overview of the geotechnical program, the study was carried out by a task group consisting of ten members with expertise in the many disciplines required to successfully complete such a project. The task group recognized from the outset that the short time frame of this study would limit its ability to address all geotechnical issues in detail. Geotechnical issues were considered to range from specific technical aspects such as in-situ testing for rock mass permeability; rock hardness testing in the laboratory; or geologic characterizations and quantification of joints, to broader aspects of design philosophy, data collection, and treatment of uncertainty. The task group chose to focus on the broader aspects of underground design and construction, recognizing that the BWIP program utilizes a peer review group on a regular basis which reviews the specific technical questions related to geotechnical engineering. In this way, it was hoped that the review provided by the task group would complement those prepared by the BWIP peer review group

  6. Assessing the potential for luminescence dating of basalts

    Science.gov (United States)

    Tsukamoto, S.; Duller, G.A.T.; Wintle, A.G.; Muhs, D.

    2011-01-01

    The possibility of dating basalt using luminescence was tested on four samples with independent age control from Cima volcanic field, California, with the ultimate aim of assessing whether the technique could be used to date sediments on the surface of Mars. Previous analysis of these samples had demonstrated that the infrared stimulated luminescence (IRSL) signal is most suitable for dating as it showed the lowest fading rate among various luminescence signals. In this study, changes in equivalent dose as a function of preheat are described. The ages for the two youngest Cima samples agree with the independent ages based on cosmogenic nuclide measurements (12.0 ?? 0.8 ka). In the two older samples (dated to 320 and 580 ka by K-Ar), the luminescence behaviour is more complex and the form of the IRSL decay curve is seen to vary with dose. Mathematical fitting is used to isolate two components and their intensities are used to produce dose response curves. The slower component yields a larger equivalent dose. However, even using this component and after correction for fading, the ages obtained for the older samples are younger than the K-Ar ages. ?? 2010 Elsevier B.V.

  7. Complex Formation History of Highly Evolved Basaltic Shergottite, Zagami

    Science.gov (United States)

    Niihara, T.; Misawa, K.; Mikouchi, T.; Nyquist, L. E.; Park, J.; Hirata, D.

    2012-01-01

    Zagami, a basaltic shergottite, contains several kinds of lithologies such as Normal Zagami consisting of Fine-grained (FG) and Coarse-grained (CG), Dark Mottled lithology (DML), and Olivine-rich late-stage melt pocket (DN). Treiman and Sutton concluded that Zagami (Normal Zagami) is a fractional crystallization product from a single magma. It has been suggested that there were two igneous stages (deep magma chamber and shallow magma chamber or surface lava flow) on the basis of chemical zoning features of pyroxenes which have homogeneous Mg-rich cores and FeO, CaO zoning at the rims. Nyquist et al. reported that FG has a different initial Sr isotopic ratio than CG and DML, and suggested the possibility of magma mixing on Mars. Here we report new results of petrology and mineralogy for DML and the Olivine-rich lithology (we do not use DN here), the most evolved lithology in this rock, to understand the relationship among lithologies and reveal Zagami s formation history

  8. On the puzzle of space weathering alteration of basaltic asteroids

    CERN Document Server

    Marchi, S; Lazzarin, M; Magrin, S

    2010-01-01

    The majority of basaltic asteroids are found in the inner main belt, although a few have also been observed in the outer main belt and near-Earth space. These asteroids -referred to as V-types- have surface compositions that resemble that of the 530km sized asteroid Vesta. Besides the compositional similarity, dynamical evidence also links many V-type asteroids to Vesta. Moreover, Vesta is one of the few asteroids to have been identified as source of specific classes of meteorites, the howardite, eucrite, diogenite achondrites (HEDs). Despite the general consensus on the outlined scenario, several questions remain unresolved. In particular, it is not clear if the observed spectral diversity among Vesta, V-types and HEDs is due to space weathering, as is thought to be the case for S-type asteroids. In this paper, SDSS photometry is used to address the question of whether the spectral diversity among candidate V-types and HEDs can be explained by space weathering. We show that visible spectral slopes of V-types...

  9. Fracture Analysis of the Ribeirao Preto Basalts, SP: Application for Developing a Conceptual Hydrogeological Model

    Directory of Open Access Journals (Sweden)

    Amélia João Fernandes

    2011-12-01

    Full Text Available The study of the physical geology and geochemistry of the Ribeirão Preto basalts was part of a hydrogeologicalresearch, which aimed to investigate the recharge of the Guarani Aquifer System (SAG through the basalts of the SerraGeral Aquifer (ASG, a project shortly named FRATASG. In addition to the hydrogeological research, a detailed geologicalinvestigation was conducted to develop a conceptual model of groundwater fl ow in complex aquifers, as is the case ofthe fractured basalts of the ASG. Therefore, this study included a thorough structural survey and analysis of horizontaland subvertical fractures, which resulted in the identifi cation of four tectonic events. It was concluded that the verticalgroundwater flow is important up to 10 m in depth and, secondarily, up to 25 m. Horizontal fl ow, more evident up to thedepth of 50 m, predominates and occurs along sub-horizontal fractures, which occur mainly at the contact between basalts2 and 3 and in its vicinity. Because the great majority of subvertical fractures do not propagate into the vesicular layers,which occur at the basalt contacts, it is suggested that these layers act as regional hydraulic barriers, and greatly hamperthe recharge of the SAG through the ASG. As a consequence, groundwater flow in the basalt stack is of stratabound type,as it occurs mainly along the basalt contacts. Based on diagnostic features of the fl ow, it is proposed in this study that the vertical flow,which crosses the basalt stack reaching the SAG, is local and probably occurs along NE structures.

  10. Growing magma chambers control the distribution of small-scale flood basalts.

    Science.gov (United States)

    Yu, Xun; Chen, Li-Hui; Zeng, Gang

    2015-01-01

    Small-scale continental flood basalts are a global phenomenon characterized by regular spatio-temporal distributions. However, no genetic mechanism has been proposed to explain the visible but overlooked distribution patterns of these continental basaltic volcanism. Here we present a case study from eastern China, combining major and trace element analyses with Ar-Ar and K-Ar dating to show that the spatio-temporal distribution of small-scale flood basalts is controlled by the growth of long-lived magma chambers. Evolved basalts (SiO2 > 47.5 wt.%) from Xinchang-Shengzhou, a small-scale Cenozoic flood basalt field in Zhejiang province, eastern China, show a northward younging trend over the period 9.4-3.0 Ma. With northward migration, the magmas evolved only slightly ((Na2O + K2O)/MgO = 0.40-0.66; TiO2/MgO = 0.23-0.35) during about 6 Myr (9.4-3.3 Ma). When the flood basalts reached the northern end of the province, the magmas evolved rapidly (3.3-3.0 Ma) through a broad range of compositions ((Na2O + K2O)/MgO = 0.60-1.28; TiO2/MgO = 0.30-0.57). The distribution and two-stage compositional evolution of the migrating flood basalts record continuous magma replenishment that buffered against magmatic evolution and induced magma chamber growth. Our results demonstrate that the magma replenishment-magma chamber growth model explains the spatio-temporal distribution of small-scale flood basalts. PMID:26581905

  11. Single and Multi-Date Landsat Classifications of Basalt to Support Soil Survey Efforts

    Directory of Open Access Journals (Sweden)

    Jessica J. Mitchell

    2013-10-01

    Full Text Available Basalt outcrops are significant features in the Western United States and consistently present challenges to Natural Resources Conservation Service (NRCS soil mapping efforts. Current soil survey methods to estimate basalt outcrops involve field transects and are impractical for mapping regionally extensive areas. The purpose of this research was to investigate remote sensing methods to effectively determine the presence of basalt rock outcrops. Five Landsat 5 TM scenes (path 39, row 29 over the year 2007 growing season were processed and analyzed to detect and quantify basalt outcrops across the Clark Area Soil Survey, ID, USA (4,570 km2. The Robust Classification Method (RCM using the Spectral Angle Mapper (SAM method and Random Forest (RF classifications was applied to individual scenes and to a multitemporal stack of the five images. The highest performing RCM basalt classification was obtained using the 18 July scene, which yielded an overall accuracy of 60.45%. The RF classifications applied to the same datasets yielded slightly better overall classification rates when using the multitemporal stack (72.35% than when using the 18 July scene (71.13% and the same rate of successfully predicting basalt (61.76% using out-of-bag sampling. For optimal RCM and RF classifications, uncertainty tended to be lowest in irrigated areas; however, the RCM uncertainty map included more extensive areas of low uncertainty that also encompassed forested hillslopes and riparian areas. RCM uncertainty was sensitive to the influence of bright soil reflectance, while RF uncertainty was sensitive to the influence of shadows. Quantification of basalt requires continued investigation to reduce the influence of vegetation, lichen and loess on basalt detection. With further development, remote sensing tools have the potential to support soil survey mapping of lava fields covering expansive areas in the Western United States and other regions of the world with similar

  12. Petrograph, Geochemistry and K-Ar Geochronolgy of the Dike systems (Nw-Se) Of te Harrat Ash Shaam Basalt In Northeast Jordan

    International Nuclear Information System (INIS)

    Chemical analyses, K-Ar dating and petrographic investigations were carried out on eight representative samples from the NW-SE basaltic dikes of the Harrat Ash Shaam Basaltic Super-Group (HAB) in northeast Jordan. In this study three phases related to the dikes were determined; the oldest took place around 23 Ma, the intermediate (12-8 Ma) and the youngest (3-1.5 Ma). The oldest dike system has the same age of the red sea (early Miocene). The basalt erupted along the dikes confirms the presence of tentional forces trending NE-SW. Every type of these dikes is related to and connected with representative and limited volcanic phase. Petrographically, five types of basaltic dikes can be distinguished; pyroxene-iddingsite basalt, olivine-iddingsite basalt; olivine basalt, pyroxene olivine basalt and iddingsite basalt. Samples range in composition from basanite to alkali basalt. (authors)

  13. Properties of composite laminates based on basalt fibers with epoxidized vegetable oils

    International Nuclear Information System (INIS)

    Highlights: • New environmentally friendly composites from biobased epoxies and basalt fibers. • Improved performance with conventional silane treatment on basalt fabrics. • Composites with excellent appearance due to basalt shiny brown color. • Potential applications as substitute of glass fiber reinforced composites in engineering design. • Processing with conventional resin transfer molding (RTM) techniques. - Abstract: This paper deals with the development of polymeric materials derived from epoxidized vegetable oils which have been used in the manufacture of laminated composite materials with basalt fabrics. Epoxidized linseed oil (ELO) and epoxidized soybean oil (ESBO) were used as biobased matrices. The basalt fabrics were modified with amino-silane and glycidyl-silane to increase fiber–matrix interactions. The curing behavior of both resins was evaluated by differential scanning calorimetry (DSC) and oscillatory rheometry (OR). The evaluation of mechanical properties was made by tensile, flexural and Charpy tests. The extent of the fiber–matrix interactions among interface was evaluated by scanning electron microscopy (SEM). The obtained results revealed that surface modification of basalt fibers with glycidyl-silane clearly improves the mechanical properties of the composites. The use of the ELO resin as matrix for composite laminates improved substantially the mechanical performance compared to composites made with ESBO

  14. Mineralogy, geochemistry and expansion testing of an alkali-reactive basalt from western Anatolia, Turkey

    International Nuclear Information System (INIS)

    In this paper, the alkali-silica reaction performance of a basalt rock from western Anatolia, Turkey is reported. It is observed that the rock causes severe gel formation in the concrete microbar test. It appears that the main source of expansion is the reactive glassy phase of the basalt matrix having approximately 70% of SiO2. The study presents the microstructural characteristics of unreacted and reacted basalt aggregate by optical and electron microscopy and discusses the possible reaction mechanism. Microstructural analysis revealed that the dissolution of silica is overwhelming in the matrix of the basalt and it eventually generates four consequences: (1) Formation of alkali-silica reaction gel at the aggregate perimeter, (2) increased porosity and permeability of the basalt matrix, (3) reduction of mechanical properties of the aggregate and (4) additional gel formation within the aggregate. It is concluded that the basalt rock is highly prone to alkali-silica reaction. As an aggregate, this rock is not suitable for concrete production.

  15. Interpretation of trace element and isotope features of basalts: relevance of field relations, petrology, major element data, phase equilibria, and magma chamber modeling in basalt petrogenesis

    Science.gov (United States)

    O'Hara, M. J.; Herzberg, C.

    2002-06-01

    The concentrations and ratios of the major elements determine the physical properties and the phase equilibria behavior of peridotites and basalts in response to the changing energy contents of the systems. The behavior of the trace elements and isotopic features are influenced in their turn by the phase equilibria, by the physical character of the partial melting and partial crystallization processes, and by the way in which a magma interacts with its wall rocks. Concentrating on the trace element and isotope contents of basalts to the exclusion of the field relations, petrology, major element data, and phase equilibria is as improvident as slaughtering the buffalo for the sake of its tongue. The crust is a cool boundary layer and a density filter, which impedes the upward transfer of hot, dense "primary" picritic and komatiitic liquids. Planetary crusts are sites of large-scale contamination and extensive partial crystallization of primitive melts striving to escape to the surface. Escape of truly unmodified primitive melts to the surface is a rare event, requiring the resolution of daunting problems in chemical and mechanical engineering. Primary status for volumetrically abundant basalts such as mid-ocean ridge basalt, ocean island basalt, and continental flood basalts is denied by their low-pressure cotectic character, first remarked upon on petrological grounds in 1928 and on experimental grounds in 1962. These basalt liquids are products of crystal-liquid separation at low pressure. Primary status for these common basalts is further denied by the phase equilibria of such compositions at elevated pressures, when the required residual mantle mineralogy (magnesian olivine and orthopyroxene) is not stable at the liquidus. It is also denied by the picritic or komatiitic nature of partial melts of candidate upper-mantle compositions at high pressures - a conclusion supported by calculation of the melt composition, which would need to be extracted in order to

  16. The investigation of gamma and neutron shielding properties of concrete including basalt fibre for nuclear energy applications

    International Nuclear Information System (INIS)

    In this study, we would like to draw attention to the prospect of basalt fibre as the main component for concrete reinforcement of NPP. This work describes the computational study of gamma attenuation parameters, the effective atomic number Z(eff) and the effective electron density Ne(eff), of relatively light-weight concrete with chopped basalt fibre used as reinforcement in different mixture rates. We can draw the following conclusions. Basalt fibre is a relatively cheap material that can be used as reinforcement instead of metallic fibers. Basalt fibre has a similar specific gravity to that of concrete elements. Basalt fibre has high chemical and abrasion resistance. Basalt fibre has almost 10 times the tensile strength of steel re-bars. Gamma-ray attenuation coefficients increase with addition of basalt fibre into concrete in every case. The effective atomic number of the concrete increases with the addition of basalt fibre. The results show that basalt fibre reinforced concrete have improved shielding properties against gamma rays in comparison with regular concrete. This result is based on a regular concrete with only basalt fiber reinforcement. We estimate that with addition of standard aggregates for radiation shielding concrete, such as barite, magnetite or hematite, the shielding properties will increase exponentially

  17. Geochemistry of cenozoic basaltic rocks from Shandong province and its implication for mantle process in North China

    International Nuclear Information System (INIS)

    Cenozoic (Miocene to Pleistocene) basaltic rocks found in Shandong province of northern China include tholeiite, olivine tholeiite and alkali basalt. We present major, trace and rare earth elements data of these basalts and together with Sr-Nd isotopic data in the literatures to discuss the petrogenesis of these basalts. The basalts from Penglai area have higher K, Na and P and incompatible elements, but lower Ca, Mg and compatible elements contents than those from Changle area of Shandong province. Spidergrams indicate that Cenozoic basalts from Shandong province have geochemical characteristics similar to those of ocean island basalts (OIB) with slight positive Nb anomaly. The negative Ba, Rb and K anomalies found in the alkali basalts suggest the presence of residual phlogopite in the mantle source, indicating a metasomatic event occurred before the partial melting. The 143Nd/144Nd vs. 87Sr/86Sr plot suggested that basalts from Shandong province can be produced by MORB and EM-I components mixing. We propose that the EM-I type lithospheric mantle may have been produced by the recent H2O-CO2 -fluids metasomatism and the fluids may be derived from dehydration of the subducted slab. Based on Shaw's equation, the basalts from eastern and central Shandong province have undergone different degrees of particle melting from the mantle source. Degrees of partial melting and chemical composition of basalts from Shandong province suggest that the lithosphere has thickened progressively since the Miocene. On the basis of Ar-Ar ages of this study and the fractional crystallization model proposed by Brooks and Nielsen (1982), we suggest that basalts from Changle and Penglai areas belong to different magmatic systems which have undergone fractional crystallization and evolved progressively to produce other types of basalts. (author)

  18. H2S Injection and Sequestration into Basalt - The SulFix Project

    Science.gov (United States)

    Gudbrandsson, S.; Moola, P.; Stefansson, A.

    2014-12-01

    Atmospheric H2S emissions are among major environmental concern associated with geothermal energy utilization. It is therefore of great importance for the geothermal power sector to reduce H2S emissions. Known solutions for H2S neutralization are both expensive and include production of elemental sulfur and sulfuric acid that needs to be disposed of. Icelandic energy companies that utilize geothermal power for electricity production have decided to try to find an environmentally friendly and economically feasible solution to reduce the H2S emission, in a joint venture called SulFix. The aim of SulFix project is to explore the possibilities of injecting H2S dissolved in water into basaltic formations in close proximity to the power plants for permanent fixation as sulfides. The formation of sulfides is a natural process in geothermal systems. Due to basalt being rich in iron and dissolving readily at acidic conditions, it is feasible to re-inject the H2S dissolved in water, into basaltic formations to form pyrite. To estimate the mineralization rates of H2S, in the basaltic formation, flow through experiments in columns were conducted at various H2S concentrations, temperatures (100 - 240°C) and both fresh and altered basaltic glass. The results indicate that pyrite rapidly forms during injection into fresh basalt but the precipiation in altered basalt is slower. Three different alteration stages, as a function of distance from inlet, can be observed in the column with fresh basaltic glass; (1) dissolution features along with precipitation, (2) precipitation increases, both sulfides and other secondary minerals and (3) the basalt looks to be unaltered and little if any precipitation is observed. The sulfur has precipitated in the first half of the column and thereafter the solution is possibly close to be supersaturated with respect to the rock. These results indicate that the H2S sequestration into basalt is possible under geothermal conditions. The rate limiting

  19. The Mantle and Basalt-Crust Interaction Below the Mount Taylor Volcanic Field, New Mexico

    Science.gov (United States)

    Schrader, Christian M.; Crumpler, Larry S.; Schmidt, Marick E.

    2010-01-01

    The Mount Taylor Volcanic Field (MTVF) lies on the Jemez Lineament on the southeastern margin of the Colorado Plateau. The field is centered on the Mt. Taylor composite volcano and includes Mesa Chivato to the NE and Grants Ridge to the WSW. MTVF magmatism spans approximately 3.8-1.5 Ma (K-Ar). Magmas are dominantly alkaline with mafic compositions ranging from basanite to hy-basalt and felsic compositions ranging from ne-trachyte to rhyolite. We are investigating the state of the mantle and the spatial and temporal variation in basalt-crustal interaction below the MTVF by examining mantle xenoliths and basalts in the context of new mapping and future Ar-Ar dating. The earliest dated magmatism in the field is a basanite flow south of Mt. Taylor. Mantle xenolith-bearing alkali basalts and basanites occur on Mesa Chivato and in the region of Mt. Taylor, though most basalts are peripheral to the main cone. Xenolith-bearing magmatism persists at least into the early stages of conebuilding. Preliminary examination of the mantle xenolith suite suggests it is dominantly lherzolitic but contains likely examples of both melt-depleted (harzburgitic) and melt-enriched (clinopyroxenitic) mantle. There are aphyric and crystal-poor hawaiites, some of which are hy-normative, on and near Mt. Taylor, but many of the more evolved MTVF basalts show evidence of complex histories. Mt. Taylor basalts higher in the cone-building sequence contain >40% zoned plagioclase pheno- and megacrysts. Other basalts peripheral to Mt. Taylor and at Grants Ridge contain clinopyroxene and plagioclase megacrysts and cumulate-textured xenoliths, suggesting they interacted with lower crustal cumulates. Among the questions we are addressing: What was the chemical and thermal state of the mantle recorded by the basaltic suites and xenoliths and how did it change with time? Are multiple parental basalts (Si-saturated vs. undersaturated) represented and, if so, what changes in the mantle or in the tectonic

  20. Bunbury Basalt: Gondwana breakup products or earliest vestiges of the Kerguelen mantle plume?

    Science.gov (United States)

    Olierook, Hugo K. H.; Jourdan, Fred; Merle, Renaud E.; Timms, Nicholas E.; Kusznir, Nick; Muhling, Janet R.

    2016-04-01

    In this contribution, we investigate the role of a mantle plume in the genesis of the Bunbury Basalt using high-precision 40Ar/39Ar geochronology and whole-rock geochemistry, and by using crustal basement thickness of the eastern Indian Ocean and the western Australian continent. The Bunbury Basalt is a series of lava flows and deep intrusive rocks in southwestern Australia thought to be the earliest igneous products from the proto-Kerguelen mantle plume. Nine new plateau ages indicate that the Bunbury Basalt erupted in three distinct phases, at 136.96 ± 0.43 Ma, 132.71 ± 0.43 Ma and 130.45 ± 0.82 Ma. All Bunbury Basalt samples are enriched tholeiitic basalts with varying contributions from the continental lithosphere that are similar to other Kerguelen plume-products. Based on plate reconstructions and the present geochronological constraints, the eruption of the oldest Bunbury Basalt preceded the emplacement of the Kerguelen large igneous province by at least 10-20 m.y. Such age differences between a precursor and the main magmatic event are not uncommon but do require additional explanation. Low crustal stretching factors beneath the Bunbury Basalt (β ≈ 1.4) indicate that decompression melting could not have been generated from asthenospheric mantle with a normal chemistry and geotherm. An elevated geotherm from the mantle plume coupled with the geochemical similarity between the Bunbury Basalt and other Kerguelen plume-products suggests a shared origin exists. However, new age constraints of the oldest Bunbury Basalt are synchronous with the breakup of eastern Gondwana and the initial opening of the Indian Ocean at ca. 137-136 Ma, which may mean an alternative explanation is possible. The enriched geochemistry can equally be explained by a patch of shallow mantle beneath the southern Perth Basin. The patch may have been enriched during Gondwana suturing at ca. 550-500 Ma, during early rifting events by magmatic underplating or by intruded melts into the

  1. The variation of magma discharge during basaltic eruptions

    Science.gov (United States)

    Wadge, G.

    1981-12-01

    The rate at which basaltic magma is discharged varies substantially during many eruptions. An individual eruption has an eruption rate ( Qe), the volumetric rate of discharge averaged over the whole or a major part of an eruption, and an effusion rate ( Qf), the volumetric flux rate at any given time. In many examples Qf soon reaches a maximum value after a short period of waxing flow, partly because of magmatic expansion, and then falls more slowly in the later parts of the eruption. The release of elastic strain energy from stored magma and the sub-volcanic reservoir during eruption can produce an exponential form of such waning flow. Comparison of the eruption rates of the historic eruptions of Mauna Loa, Kilauea and Etna shows that for each volcano there is a trend of decreasing Qe with increasing duration of eruption. This relationship is not predicted by a simple elastic model of magma release. Two additional processes are invoked to explain the eruptive histories of these volcanoes: modification of the eruptive conduits, and the continued supply of magma from depth during eruption. Conduits evolving from dikes to plugs by wall-rock erosion or freezing of magma can result in increased early values of Qf and the maintenance of very low values of Qf values for long periods later in the eruption. Discharge variations during three specific eruptions are discussed in detail. Paricutin (1943-1952) had exponentially waning flow, with a time constant of about three years, that is consistent with a deep reservoir. The waning flow of Hekla's 1947-1948 eruption showed some of the characteristics of conduit modification, whilst the 1959 Kilauea Iki eruption is interpreted in terms of a closed system with varying magma rheology.

  2. Spectral characterization of acid weathering products on Martian basaltic glass

    Science.gov (United States)

    Yant, Marcella; Rogers, A. Deanne; Nekvasil, Hanna; Zhao, Yu-Yan Sara; Bristow, Tom

    2016-03-01

    For the first time, direct infrared spectral analyses of glasses with Martian compositions, altered under controlled conditions, are presented in order to assess surface weathering and regolith development on Mars. Basaltic glasses of Irvine and Backstay composition were synthesized and altered using H2SO4-HCl acid solutions (pH 0-4). Scanning electron microscopy/energy dispersive spectroscopy, X-ray diffraction, Raman, and infrared spectral measurements were acquired for each reaction product. Infrared spectra were also acquired from previously synthesized and altered glasses with Pathfinder-measured compositions. Acid alteration on particles in the most acidic solutions (pH ≤ 1) yielded sulfate-dominated visible near infrared (VNIR) and thermal infrared (TIR) spectra with some silica influence. Spectral differences between alteration products from each starting material were present, reflecting strong sensitivity to changes in mineral assemblage. In the TIR, alteration features were preserved after reworking and consolidation. In the VNIR, hydrated sulfate features were present along with strong negative spectral slopes. Although such signatures are found in a few isolated locations on Mars with high-resolution spectrometers, much of the Martian surface lacks these characteristics, suggesting the following: acid alteration occurred at pH ≥ 2; small amounts of sulfates were reworked with unaltered material; there is a prevalence of intermediate-to-high silica glass in Martian starting materials (more resistant to acid alteration); primary or added sulfur were lacking; alteration features are obscured by dust; and/or large-scale, pervasive, acid sulfate weathering of the Martian surface did not occur. These results highlight the need to better understand the spectral properties of altered Martian surface material in order to enhance the interpretation of remote spectra for altered terrains.

  3. Deformation of basaltic shield volcanoes under cointrusive stress permutations

    Science.gov (United States)

    Chaput, Marie; Famin, Vincent; Michon, Laurent

    2014-01-01

    We performed a microstructural study of Piton des Neiges (La Réunion Island) to understand how intrusions and stresses control each other in basaltic volcanoes. Our study reveals that three perpendicular intrusions trends coexisted during the 2 Myr history of the volcano: a N120-140°E rift zone, a perpendicular dike trend, and swarms of subhorizontal intrusions hereafter called "sill zones". Independently, the inversion of fault-slip data shows that incompatible paleostress fields recurrently occurred along with the intrusions: a dominant NNE-SSW extension, a perpendicular extension, and strike-slip or compressional regimes. The orientations of paleostresses are consistent with the orientations of the three perpendicular intrusion populations. We propose that stress accumulation in the edifice under the effect of repeated magma injections resulted in permutations of the principal axes of the stress tensor, causing a reorientation of subsequent intrusions. Stress permutations were cyclical. Each cycle started with dike injections in an extensional stress field, reducing the deviatoric stress and switching the axes of principal stresses, and finished with sill intrusions in a compressional stress field. Sill zones acted as detachment planes, restoring the extensional stress field and initiating a new cycle of permutations. Our model of stress permutations is in agreement with the pattern of eruptions and deformation observed at Piton de la Fournaise. In contrast with the Hawaiian model of spreading on a décollement, stress permutations in La Réunion's volcanoes imply that the basal deformation of the edifices, if any, is not sufficient to compensate the reduction of deviatoric stress caused by intrusions.

  4. Magnetic depths to basalts: extension of spectral depths method

    Science.gov (United States)

    Clifton, Roger

    2015-11-01

    Although spectral depth determination has played a role in magnetic interpretation for over four decades, automating the procedure has been inhibited by the need for manual intervention. This paper introduces the concept of a slope spectrum of an equivalent layer, to be used in an automated depth interpretation algorithm suitable for application to very large datasets such as the complete Northern Territory aeromagnetic grid. In order to trace the extensive basalts across the Northern Territory, profiles of spectral depths have been obtained at 5 km intervals across the NT stitched grid of total magnetic intensity (TMI). Each profile is a graph from 0 to 1000 m of the probability of a magnetic layer occurring at each depth. Automating the collection of the 50 000 profiles required the development of a formula that relates slopes along the power spectrum to depths to an equivalent magnetic layer. Model slabs were populated with a large number of randomly located dipoles and their power spectra correlated with modelled depth to provide the formula. Depth profiles are too noisy to be used singly, but when a series of depth profiles are lined up side-by-side as a transect, significant magnetic layers can be traced for large distances. Transects frequently show a second layer. The formula is quite general in its derivation and would apply to any mid-latitude area where significant magnetic bodies can be modelled as extensive layers. Because the method requires a radial power spectrum, it fails to provide signal at depths much shallower than the flight line spacing. The method is convenient for a fast first pass at depth estimation, but its horizontal resolution is rather coarse and errors can be quite large.

  5. Carbonaceous matter and putative microfossils of the mid-Archean Kromberg type-section re-visited, Barberton Greenstone Belt, South Africa

    Science.gov (United States)

    McLoughlin, Nicola; Grosch, Eugene

    2014-05-01

    Silicified seafloor sediments of the Kromberg Formation from the Onverwacht Group of the Barberton greenstone belt (BGB), South Africa, have been argued to contain some of the world's oldest preserved carbonaceous microfossils. Previous studies of these cherts have reported filamentous, spheroidal and ellipsoidal microfossils in thin-section (Walsh 1992); and bacteriomorph like structures in HF-etched samples (Westall et al. 2001). These microtextural studies however, lack supporting in-situ geochemical data, and are hampered to some degree by re-mobilisation of the carbonaceous matter (Van Zuilen et al. 2007). In light of these concerns, and ongoing debates surrounding carbonaceous remains in other Archean cherts (e.g., W Australia), further in-situ data from the Kromberg is required to positively identify carbonaceous matter of biogenic origin. New data will also help to address outstanding questions regarding the relative contribution of benthic versus planktonic microorganisms, and the putative microbial metabolisms involved. This study focuses on surface samples and drill core from the Barberton Scientific Drilling Programme, (BSDP, Grosch et al. 2009) from the southeastern limb of the Onverwacht anticline of the BGB. We sampled the Footbridge chert and a second chert horizon in drill core KD1 of the BSDP in the upper Kromberg Fm; and surface outcrops of two black cherts from the lower Kromberg Fm. Sedimentological logging reveals horizons rich in volcaniclastics with interbedded finely laminated grey-black chert, also intrusive black cherts, and sulphide rich horizons. The TOC of the sampled cherts is 1.24 to 5.40 wt%. Preliminary bulk carbon isotope values range from δ13C -21.1 to -35.3o values that are consistent with organic matter produced by anoxygenic photosynthesis. Microfabrics preserved in the Kromberg cherts include, primary wispy-laminated carbonaceous films suggesting compaction of early carbonaceous laminae. Also large composite carbonaceous

  6. Multiple sulfur and carbon isotope composition of sediments from the Belingwe Greenstone Belt (Zimbabwe): A biogenic methane regulation on mass independent fractionation of sulfur during the Neoarchean?

    Science.gov (United States)

    Thomazo, Christophe; Nisbet, Euan G.; Grassineau, Nathalie V.; Peters, Marc; Strauss, Harald

    2013-11-01

    To explore the linkage between mass-independent sulfur isotope fractionation (MIF-S) and δ13Corg excursions during the Neoarchean, as well as the contemporary redox state and biogeochemical cycling of carbon and sulfur, we report the results of a detailed carbon and multiple sulfur (δ34S, δ33S, δ36S) isotopic study of the ∼2.7 Ga Manjeri and ∼2.65 Ga Cheshire formations of the Ngezi Group (Belingwe Greenstone Belt, Zimbabwe). Multiple sulfur isotope data show non-zero Δ33S and Δ36S values for sediments older than 2.4 Ga (i.e. prior to the Great Oxidation Event, GOE), indicating MIF-S thought to be associated with low atmospheric oxygen concentration. However, in several 2.7-2.5 Ga Neoarchean localities, small-scale variations in MIF-S signal (magnitude) seem to correlate with negative excursion in δ13Corg, possibly reflecting a global connection between the relative reaction rate of different MIF-S source reaction and sulfur exit channels and the biogenic flux of methane into the atmosphere during periods of localized, microbiologically mediated, shallow surface-water oxygenation. The Manjeri Formation black shales studied here display a wide range of δ13Corg between -35.4‰ and -16.2‰ (average of -30.3 ± 6.0‰, 1σ), while the Cheshire Formation shales have δ13Corg between -47.7‰ and -35.1‰ (average -41.3 ± 3‰, 1σ). The δ34S values of sedimentary sulfides from Manjeri Formation vary between -15.15‰ and +2.37‰ (average -1.71 ± 4.76‰, 1σ), showing very small and mostly negative Δ33S values varying from -0.58‰ to 0.87‰ (average 0.02 ± 0.43‰, 1σ). Cheshire Formation black shale sulfide samples measured in this study have δ34S values ranging from -2.11‰ to 2.39‰ (average 0.25 ± 1.08‰, 1σ) and near zero and solely positive Δ33S anomalies between 0.14‰ and 1.17‰ (average 0.56 ± 0.29‰, 1σ). Moreover, Δ36S/Δ33S in the two formations are comparable with a slope of -1.38 (Manjeri Formation) and -1.67 (Cheshire

  7. A brief comparison of lava flows from the Deccan Volcanic Province and the Columbia-Oregon Plateau Flood Basalts: Implications for models of flood basalt emplacement

    Indian Academy of Sciences (India)

    Ninad Bondre; Raymond A Duraiswami; Gauri Dole

    2004-12-01

    The nature and style of emplacement of Continental Flood Basalt (CFB) lava flows has been a atter of great interest as well as considerable controversy in the recent past. However, even a cursory review of published literature reveals that the Columbia River Basalt Group (CRBG) and Hawaiian volcanoes provide most of the data relevant to this topic. It is interesting to note, however, that the CRBG lava flows and their palaeotopographic control is atypical of other CFB provinces in the world. In this paper, we first present a short overview of important studies pertaining to the emplacement of flood basalt flows. We then briefly review the morphology of lava flows from the Deccan Volcanic Province (DVP) and the Columbia-Oregon Plateau flood basalts. The review underscores the existence of significant variations in lava flow morphology between different provinces, and even within the same province. It is quite likely that there were more than one way of emplacing the voluminous and extensive CFB lava flows. We argue that the establishment of general models of emplacement must be based on a comprehensive documentation of lava flow morphology from all CFB provinces.

  8. Autogenous Tumbling Media Assessment to Clean Weathered Surfaces of Waste-Rock Particles from a Basalt Quarry

    Directory of Open Access Journals (Sweden)

    Baran Tufan

    2015-06-01

    Full Text Available In this study, the optimum feed composition in autogenous tumbling of basalt waste-rock particles to clean their weathered surface was determined. The weathered surfaces of basalt are generally cut out consequent to extraction of basalt columns in quarry operations. The inefficiently cut out portions of basalt cause formation of huge quarry waste dumps causing visual pollution on roadsides. Mixtures of different particle size fractions of basalt waste-rock particles were experimented to achieve the optimum feed material composition. The minimum loss of commercially available basalt particles and maximum clear surface was intended. The results were compared with respect to weight loss (% and reflectance values of used and generated samples.

  9. Development and evaluation of a thermodynamic dataset for phases of interest in CO2 mineral sequestration in basaltic rocks

    OpenAIRE

    Edda S.P. Aradóttir, Eric L. Sonnenthal and Hannes Jónsson

    2012-01-01

    A thermodynamic dataset describing 36 mineral reactions of interest for CO2–water–basalt interaction associated with CO2 mineral sequestration in basaltic formations is presented. Mineral selection for the dataset is based on extensive review of natural analogs of water–basalt interaction at low and elevated CO2 conditions. Widely used thermodynamic databases did not contain the mineral assemblage needed for successfully simulating the alteration processes observ...

  10. Magmatic evolution of the fresh basalts from the Ridge axis near Egaria Fracture Zone, Central Indian Ridge

    Digital Repository Service at National Institute of Oceanography (India)

    Mudholkar, A.V.

    basalts is higher (~9%) as compared to normal MORB (BVSP, 1981). This higher concentration of the FeO* is also indicative of the evolution or fractionation of the SK basalts from the parental basaltic melt. Effects of the magmatic processes... (64.8 to 65.9) while CaO/Al2O3 ratio changes from 0.69 in B5 (parental) to 0.76 in B1 (evolved) indicating the effects of plagioclase fractionation (Dungan and Rhodes, 1978). The basalts studied by Price et al. (1986) and Humler and Whitechurch (1988...

  11. Technical support for GEIS: radioactive waste isolation in geologic formations. Volume 3. Stratigraphies of salt, granite, shale, and basalt

    International Nuclear Information System (INIS)

    This study presents the methodology and basic literature used to develop generic stratigraphic sections for the various geologic repository host rocks under considerations: salt, granite, shale and basalt

  12. Technical support for GEIS: radioactive waste isolation in geologic formations. Volume 7. Baseline rock properties-basalt

    Energy Technology Data Exchange (ETDEWEB)

    1978-04-01

    This volume, Y/OWI/TM-36/7 Baseline Rock Properties--Basalt, is one of a 23-volume series, ''Technical Support for GEIS: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-36'' which supplements a ''Contribution to Draft Generic Environmental Impact Statement on Commercial Waste Management: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-44.'' The series provides a more complete technical basis for the preconceptual designs, resource requirements, and environmental source terms associated with isolating commercial LWR wastes in underground repositories in salt, granite, shale and basalt. Wastes are considered from three fuel cycles: uranium and plutonium recycling, no recycling of spent fuel and uranium-only recycling. This report contains an evaluation of the results of a literature survey to define the rock mass properties of a generic basalt, which could be considered as a geological medium for storing radioactive waste. The general formation and structure of basaltic rocks is described. This is followed by specific descriptions and rock property data for the Dresser Basalt, the Amchitka Island Basalt, the Nevada Test Site Basalt and the Columbia River Group Basalt. Engineering judgment has been used to derive the rock mass properties of a typical basalt from the relevant intact rock property data and the geological information pertaining to structural defects, such as joints and faults.

  13. Technical support for GEIS: radioactive waste isolation in geologic formations. Volume 7. Baseline rock properties-basalt

    International Nuclear Information System (INIS)

    This volume, Y/OWI/TM-36/7 Baseline Rock Properties--Basalt, is one of a 23-volume series, ''Technical Support for GEIS: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-36'' which supplements a ''Contribution to Draft Generic Environmental Impact Statement on Commercial Waste Management: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-44.'' The series provides a more complete technical basis for the preconceptual designs, resource requirements, and environmental source terms associated with isolating commercial LWR wastes in underground repositories in salt, granite, shale and basalt. Wastes are considered from three fuel cycles: uranium and plutonium recycling, no recycling of spent fuel and uranium-only recycling. This report contains an evaluation of the results of a literature survey to define the rock mass properties of a generic basalt, which could be considered as a geological medium for storing radioactive waste. The general formation and structure of basaltic rocks is described. This is followed by specific descriptions and rock property data for the Dresser Basalt, the Amchitka Island Basalt, the Nevada Test Site Basalt and the Columbia River Group Basalt. Engineering judgment has been used to derive the rock mass properties of a typical basalt from the relevant intact rock property data and the geological information pertaining to structural defects, such as joints and faults

  14. The Giant Lavas of Kalkarindji: rubbly pāhoehoe lava in an ancient continental flood basalt province

    OpenAIRE

    Marshall, Peter E.; Widdowson, Mike; Murphy, David T.

    2016-01-01

    The Kalkarindji continental flood basalt province of northern Australia erupted in the mid Cambrian (c. 511-505 Ma). It now consists of scattered basaltic lava fields, the most extensive being the Antrim Plateau Volcanics (APV) - a semi-continuous outcrop (c. 50,000 km2) reaching a maximum thickness of 1.1 km. Cropping out predominately in the SW of the APV, close to the top of the basalt succession, lies the Blackfella Rockhole Member (BRM). Originally described as ‘basaltic agglomerate’ the...

  15. Viscous flow behavior of tholeiitic and alkaline Fe-rich martian basalts

    Science.gov (United States)

    Chevrel, Magdalena Oryaëlle; Baratoux, David; Hess, Kai-Uwe; Dingwell, Donald B.

    2014-01-01

    The chemical compositions of martian basalts are enriched in iron with respect to terrestrial basalts. Their rheology is poorly known and liquids of this chemical composition have not been experimentally investigated. Here, we determine the viscosity of five synthetic silicate liquids having compositions representative of the diversity of martian volcanic rocks including primary martian mantle melts and alkali basalts. The concentric cylinder method has been employed between 1500 °C and the respective liquidus temperatures of these liquids. The viscosity near the glass transition has been derived from calorimetric measurements of the glass transition. Although some glass heterogeneity limits the accuracy of the data near the glass transition, it was nevertheless possible to determine the parameters of the non-Arrhenian temperature-dependence of viscosity over a wide temperature range (1500 °C to the glass transition temperature). At superliquidus conditions, the martian basalt viscosities are as low as those of the Fe-Ti-rich lunar basalts, similar to the lowest viscosities recorded for terrestrial ferrobasalts, and 0.5 to 1 order of magnitude lower than terrestrial tholeiitic basalts. Comparison with empirical models reveals that Giordano et al. (2008) offers the best approximation, whereas the model proposed by Hui and Zhang (2007) is inappropriate for the compositions considered. The slightly lower viscosities exhibited by the melts produced by low degree of mantle partial melting versus melts produced at high degree of mantle partial melting (likely corresponding to the early history of Mars), is not deemed sufficient to lead to viscosity variations large enough to produce an overall shift of martian lava flow morphologies over time. Rather, the details of the crystallization sequence (and in particular the ability of some of these magmas to form spinifex texture) is proposed to be a dominant effect on the viscosity during martian lava flow emplacement and

  16. Siderophile and chalcophile metal variations in Tertiary picrites and basalts from West Greenland with implications for the sulphide saturation history of continental flood basalt magmas

    Science.gov (United States)

    Keays, Reid R.; Lightfoot, Peter C.

    2007-04-01

    Sixty-five million year old continental flood basalts crop out on Qeqertarssuaq Island and the Nuussuaq Peninsula in West Greenland, and they include ˜1,000 m of picritic lavas and discrete 10- to 50-m-thick members of highly contaminated basalts. On Qeqertarssuaq, the lavas are allocated to the Vaîgat and Maligât Formations of which the former includes the Naujánguit member, which consists of picrites with 7-29 wt% MgO, 80-1,400 ppm Ni, 5.7-9.4 ppb Pt and 4.2-12.9 ppb Pd. The Naujánguit member contains two horizons of contaminated basalts, the Asûk and Kûgánguaq, which have elevated SiO2 (52-58 wt%) and low to moderate MgO (7.5-12.8 wt%). These lavas are broadly characterized by low Cu and Ni abundances (average, 40 ppm Ni and 45 ppm Cu) and very low Pt (0.16-0.63 ppb) and Pd (0.13-0.68 ppb) abundances, and in the case of the Asûk, they contain shale xenoliths and droplets of native iron and troilite. The contaminated basalts from Nuussuaq, the B0 to B4 members, are also usually Ni-, Cu-, and platinum-group elements (PGE)-depleted. The geochemical signatures (especially the ratios of incompatible trace elements such as Th/Nb) of all of the contaminated basalts from Qeqertarssuaq and some of those from Nuussuaq record what appears to be a chemical contribution from deltaic shales that lie immediately below the lavas. This suggests that the contamination of the magmas occurred during the migration of the magmas through plumbing systems developed in sedimentary rocks, and hence, at a high crustal level. Nickel, Cu, and PGE depletion together with geochemical signatures produced by crustal contamination are also a feature of Siberian Trap basalts from the Noril’sk region. These basalts belong to the 0- to 500-m thick, ˜5,000- to 10,000-km3 Nadezhdinsky Formation, which is centered in the Noril’sk Region. A major difference between Siberia and West Greenland is that PGE depletion in the Nadezhdinsky Formation samples with the lowest Cu and Ni contents is

  17. Non-destructive XRF analyses of fine-grained basalts from Eiao, Marquesas Islands

    International Nuclear Information System (INIS)

    The Marquesan island of Eiao was an important source of fine-grained basalt in Central East Polynesia, with examples being identified in archaeological assemblages throughout the region. However, compared to many other large-scale Polynesian basalt sources, little has been published about the physical extent and geochemical variability of tool-quality basalt on Eiao; prior to our study, only a single site with evidence of stone extraction had been identified and geochemical information was limited to less than two dozen samples. In this paper we report geochemical data for 225 additional basalt specimens collected on Eiao. Our analyses were conducted non-destructively using three EDXRF instruments: one lab-based unit and two portable analysers. The majority of our sample, identified here as Group 1, possesses geochemical and physical characteristics similar to those reported in previous studies. Group 1 samples were collected from various locations on Eiao suggesting that, rather than being limited to a single quarry site, fine-grained basalt was extracted from multiple sources throughout the island. In addition, we identified a second group (Group 2), which possesses a distinct geochemistry, a coarser grain and often an unusual reddish colour. Evidence from Eiao indicates that Group 2 stone was regularly utilised and our analysis of an adze collected on Hiva Oa Island suggests that this material was distributed at least as far as the southern Marquesas. (author)

  18. A novel basalt fiber-reinforced polylactic acid composite for hard tissue repair

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xi; Li Yan; Gu Ning, E-mail: guning@seu.edu.c [Jiangsu Laboratory for Biomaterials and Devices, State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096 (China)

    2010-08-01

    A basalt fiber (BF) was, for the first time, introduced into a poly(l-lactic acid) (PLLA) matrix as innovative reinforcement to fabricate composite materials for hard tissue repair. Firstly, BF/PLLA composites and pure PLLA were produced by the methods of solution blending and freeze drying. The results showed that basalt fibers can be uniformly dispersed in the PLLA matrix and significantly improve the mechanical properties and hydrophilicity of the PLLA matrix. The presence of basalt fibers may retard the polymer degradation rate and neutralize the acid degradation from PLLA. Osteoblasts were cultured in vitro to evaluate the cytocompatibility of the composite. An MTT assay revealed that osteoblasts proliferated well for 7 days and there was little difference found in their viability on both PLLA and BF/PLLA films, which was consistent with the alkaline phosphatase (ALP) activity results. A fluorescent staining observation showed that osteoblasts grew well on the composites. SEM images displayed that osteoblasts tended to grow along the fiber axis. The formation of mineralized nodules was observed on the films by Alizarin red S staining. These results suggest that the presence of basalt fibers does not noticeably affect osteoblastic behavior and the designed composites are osteoblast compatible. It is concluded that basalt fibers, as reinforcing fibers, may have promising applications in hard tissue repair.

  19. A novel basalt fiber-reinforced polylactic acid composite for hard tissue repair

    International Nuclear Information System (INIS)

    A basalt fiber (BF) was, for the first time, introduced into a poly(l-lactic acid) (PLLA) matrix as innovative reinforcement to fabricate composite materials for hard tissue repair. Firstly, BF/PLLA composites and pure PLLA were produced by the methods of solution blending and freeze drying. The results showed that basalt fibers can be uniformly dispersed in the PLLA matrix and significantly improve the mechanical properties and hydrophilicity of the PLLA matrix. The presence of basalt fibers may retard the polymer degradation rate and neutralize the acid degradation from PLLA. Osteoblasts were cultured in vitro to evaluate the cytocompatibility of the composite. An MTT assay revealed that osteoblasts proliferated well for 7 days and there was little difference found in their viability on both PLLA and BF/PLLA films, which was consistent with the alkaline phosphatase (ALP) activity results. A fluorescent staining observation showed that osteoblasts grew well on the composites. SEM images displayed that osteoblasts tended to grow along the fiber axis. The formation of mineralized nodules was observed on the films by Alizarin red S staining. These results suggest that the presence of basalt fibers does not noticeably affect osteoblastic behavior and the designed composites are osteoblast compatible. It is concluded that basalt fibers, as reinforcing fibers, may have promising applications in hard tissue repair.

  20. A novel basalt fiber-reinforced polylactic acid composite for hard tissue repair.

    Science.gov (United States)

    Chen, Xi; Li, Yan; Gu, Ning

    2010-08-01

    A basalt fiber (BF) was, for the first time, introduced into a poly(l-lactic acid) (PLLA) matrix as innovative reinforcement to fabricate composite materials for hard tissue repair. Firstly, BF/PLLA composites and pure PLLA were produced by the methods of solution blending and freeze drying. The results showed that basalt fibers can be uniformly dispersed in the PLLA matrix and significantly improve the mechanical properties and hydrophilicity of the PLLA matrix. The presence of basalt fibers may retard the polymer degradation rate and neutralize the acid degradation from PLLA. Osteoblasts were cultured in vitro to evaluate the cytocompatibility of the composite. An MTT assay revealed that osteoblasts proliferated well for 7 days and there was little difference found in their viability on both PLLA and BF/PLLA films, which was consistent with the alkaline phosphatase (ALP) activity results. A fluorescent staining observation showed that osteoblasts grew well on the composites. SEM images displayed that osteoblasts tended to grow along the fiber axis. The formation of mineralized nodules was observed on the films by Alizarin red S staining. These results suggest that the presence of basalt fibers does not noticeably affect osteoblastic behavior and the designed composites are osteoblast compatible. It is concluded that basalt fibers, as reinforcing fibers, may have promising applications in hard tissue repair. PMID:20683132

  1. A deterministic methodology for prediction of fracture distribution in basaltic multiflows

    Science.gov (United States)

    Lore, Jason; Aydin, Atilla; Goodson, Kenneth

    2001-04-01

    The fracture distribution in basalt flows is a direct result of thermal processes. Thus basalt flows present a unique opportunity to characterize a nearly perfect deterministic system with its fundamental physical parameters. Fracture distribution data collected on cliff exposures of basalt flows near the Idaho National Engineering and Environmental Laboratory (INEEL) are combined with calculations of cooling rate and temperature distribution from a finite element model to construct a predictive methodology for fracture spacing. The methodology is based on an empirical power law relationship between inverse cooling rate and fracture spacing. The methodology may be applied to unexposed basalt flows of approximately elliptical cross section whose thickness and width are constrained only by geophysical or borehole data if sufficient fracture data on nearby exposed flows are available. The methodology aids waste remediation efforts at sites involving contaminant transport through fractured basalt, such as the INEEL and the Hanford site in Washington, as well as involving transport and fluid flow through volcanic or intrusive rocks where thermal processes are responsible for fracturing.

  2. Degradation of basalt fibre and glass fibre/epoxy resin composites in seawater

    International Nuclear Information System (INIS)

    Research highlights: → BFRP degradation process in seawater environment was first investigated. → The mass gain change includes two effects: absorption and extraction. → The interfacial adhesion of BFRP is bigger than GFRP. → After treated, the bending strength of BFRP is lower than GFRP. → Reducing the Fe2+ in the basalt fibre could lead to a higher stability of BFRP. - Abstract: Epoxy resins reinforced, respectively, by basalt fibres and glass fibres were treated with a seawater solution for different periods of time. Both the mass gain ratio and the strength maintenance ratio of the composites were examined after the treatment. The fracture surfaces were characterized using scanning electron microscopy. The tensile and bending strengths of the seawater treated samples showed a decreasing trend with treating time. In general, the anti-seawater corrosion property of the basalt fibre reinforced composites was almost the same as that of the glass fibre reinforced ones. Based on the experimental results, possible corrosion mechanisms were explored, indicating that an effective lowering of the Fe2+ content in the basalt fibre could lead to a higher stability for the basalt fibre reinforced composites in a seawater environment.

  3. Degradation of basalt fibre and glass fibre/epoxy resin composites in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Wei Bin [Department of Materials Science and Engineering, Shenzhen Graduate School, Harbin Institute of Technology, Xili, Shenzhen 518055 (China); Cao Hailin, E-mail: caohl@hit.edu.c [Harbin Institute of Technology, Harbin 150001 (China); Shenzhen Aerospace Tech-Innovation Institute, Shenzhen Key Laboratory of Composite Materials, Shenzhen 518057 (China); Song Shenhua [Department of Materials Science and Engineering, Shenzhen Graduate School, Harbin Institute of Technology, Xili, Shenzhen 518055 (China)

    2011-01-15

    Research highlights: {yields} BFRP degradation process in seawater environment was first investigated. {yields} The mass gain change includes two effects: absorption and extraction. {yields} The interfacial adhesion of BFRP is bigger than GFRP. {yields} After treated, the bending strength of BFRP is lower than GFRP. {yields} Reducing the Fe{sup 2+} in the basalt fibre could lead to a higher stability of BFRP. - Abstract: Epoxy resins reinforced, respectively, by basalt fibres and glass fibres were treated with a seawater solution for different periods of time. Both the mass gain ratio and the strength maintenance ratio of the composites were examined after the treatment. The fracture surfaces were characterized using scanning electron microscopy. The tensile and bending strengths of the seawater treated samples showed a decreasing trend with treating time. In general, the anti-seawater corrosion property of the basalt fibre reinforced composites was almost the same as that of the glass fibre reinforced ones. Based on the experimental results, possible corrosion mechanisms were explored, indicating that an effective lowering of the Fe{sup 2+} content in the basalt fibre could lead to a higher stability for the basalt fibre reinforced composites in a seawater environment.

  4. Selective environmental stress from sulphur emitted by continental flood basalt eruptions

    Science.gov (United States)

    Schmidt, Anja; Skeffington, Richard A.; Thordarson, Thorvaldur; Self, Stephen; Forster, Piers M.; Rap, Alexandru; Ridgwell, Andy; Fowler, David; Wilson, Marjorie; Mann, Graham W.; Wignall, Paul B.; Carslaw, Kenneth S.

    2016-01-01

    Several biotic crises during the past 300 million years have been linked to episodes of continental flood basalt volcanism, and in particular to the release of massive quantities of magmatic sulphur gas species. Flood basalt provinces were typically formed by numerous individual eruptions, each lasting years to decades. However, the environmental impact of these eruptions may have been limited by the occurrence of quiescent periods that lasted hundreds to thousands of years. Here we use a global aerosol model to quantify the sulphur-induced environmental effects of individual, decade-long flood basalt eruptions representative of the Columbia River Basalt Group, 16.5-14.5 million years ago, and the Deccan Traps, 65 million years ago. For a decade-long eruption of Deccan scale, we calculate a decadal-mean reduction in global surface temperature of 4.5 K, which would recover within 50 years after an eruption ceased unless climate feedbacks were very different in deep-time climates. Acid mists and fogs could have caused immediate damage to vegetation in some regions, but acid-sensitive land and marine ecosystems were well-buffered against volcanic sulphur deposition effects even during century-long eruptions. We conclude that magmatic sulphur from flood basalt eruptions would have caused a biotic crisis only if eruption frequencies and lava discharge rates had been high and sustained for several centuries at a time.

  5. The Composition of the Fluids in Alkali Basalts and Mantle-Derived Xenoliths in Eastern China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Minjie; WANG Xianbin; LIU Gang; LI Liwu

    2001-01-01

    The components of the fluids released from alkali basalts and mantle-derived Iherzolite xenoliths in eastern China have been determined by the vacuum pyrolysis-mass spectrometric (MS) method in the present study. The results show that mantle-derived lherzolites formed in fluids composed mainly of reducing gases such as H2 and CO, and their fluid composition is characterized by a higher H2 content and a lower total content of volatiles. The fluids in alkali basalts are composed mainly of oxidizing gases, such as CO2 an SO2 and characterized by higher contents of SO2 and volatiles,implying that the extraneous oxidized fluids which are composed mainly of SO2 mixed with primary alkali basaltic magmas during their formation and evolution. The fluid compositions of alkali basalts and Iherzolite xenoliths show high nonhomogeneity in the upper mantle source region and difference in alkali basaltic magma evolution in different districts. It can be deduced that the region with higher PH2 could exist in the upper mantle beneath eastern China.

  6. A brief review of the petrology of lunar mare basalts and a case study

    International Nuclear Information System (INIS)

    Of all the lunar rock types the basalts which occupy the low-lying mare plains have been studied the most. In general, the mare basalts are chemically classified as: high-Ti group and low Ti-group. Experimental petrologic studies indicate that the chemical variations in the Ti and K contents are due to partial melting of different materials at different depths of the lunar interior corresponding to pressures of approximately 5kb to approximately 20kb. The high-K variety of basalt tends to have an intersertal texture. While the low-K variety tends to be ophitic. Otherwise, the wide range of textures, from pyroxene vitrophyric to plagioclase-pikilitic, displayed by the mare basalts depends essentially on cooling history, not on composition. The cooling history of each rock, as well as the bulk chemical composition of its parent melt have left a definite signature in the chemical zoning of its rock forming minerals, pyroxenes in particular. One particular Apollo 11 high-Ti/Ow-K ophitic medium-grained basalt fragment is described with emphasis on the chemical zoning in pyroxenes. This rock appears to be the product of near-surface crystallization, probably after an earlier stage of olivine and chromite fractionation has increased the Al content of its parent melt. (author)

  7. Hydrogeological and quantitative groundwater assessment of the Basaltic Aquifer, Northern Harrat Rahat, Saudi Arabia

    International Nuclear Information System (INIS)

    The Northern Harrat Rahat consists of 300m basalt lavas covering some 2000 km2 to the south-east of Al-Madinah in western Saudi Arabia. Like many basalt sequences, the Rahat basalts form an important aquifer and groundwater resource. The aquifer has a saturated thickness of up to 60m and made up of the weathered upper part of underlying basement, pre-basalt sands and gravels and the fractured basalts. Since 1992, groundwater has been abstracted from the aquifer as part of the Al-Madinah water supply. To assess the potential of the aquifer an assessment has been made based on pumping tests of 70 wells. The hydraulic parameters have been shown to be highly variable typical of the fractured domain. The aquifer contains good-quality water in storage, but receives limited recharge. Groundwater temperature anomalies indicate remnant volcanic activity locally. A numerical groundwater model has been constructed, which has been calibrated using limited groundwater head measurements, but with good abstraction records. Prediction of groundwater heads and the examination of several abstraction scenarios indicate that the aquifer can continue to support part of the Al-Madinah demand for the next several years, if certain well distributions are adopted. The predictions also show that the aquifer can only support the total demand of the city for a few days as a contingency resource. (author)

  8. Preconceptual systems and equipment for plugging of man-made accesses to a repository in basalt

    International Nuclear Information System (INIS)

    This report presents results of a study leading to preconceptual designs for plugging boreholes, shafts, and tunnels to a nuclear waste repository in basalt. Beginning design criteria include a list of preferred plug materials and plugging machines that were selected to suit the environmental conditions, and depths, diameters, and orientations of the accesses to a nuclear waste repository in the Columbia River basalts located in eastern Washington State. The environmental conditions are described. The fiscal year 1979-1980 Task II work is presented in two parts: preliminary testing of materials for plugging of man-made accesses to a repository in basalt (described in a separate report); and preconceptual systems and equipment for plugging of man-made accesses to a repository in basalt (described in this report). To fulfill the scope of the Task II work, Woodward-Clyde Consultants (WCC) was requested to: provide preconceptual systems for plugging boreholes, tunnels, and shafts in basalt; describe preconceptual borehole plugging equipment for placing the selected materials in man-made accesses; utilize the quality assurance program, program plan and schedule, and work plans previously developed for Task II; and prepare a preliminary report

  9. Source, evolution and emplacement of Permian Tarim Basalts: Evidence from U-Pb dating, Sr-Nd-Pb-Hf isotope systematics and whole rock geochemistry of basalts from the Keping area, Xinjiang Uygur Autonomous region, northwest China

    Science.gov (United States)

    Zhang, Dayu; Zhou, Taofa; Yuan, Feng; Jowitt, Simon M.; Fan, Yu; Liu, Shuai

    2012-04-01

    Permian basalts distribute at least 250,000 km2, and underlie the southwest Tarim Basin in Xinjiang Uygur Autonomous region, northwest China. This vast accumulation of basalt is the main part of the Tarim Large Igneous Province (LIP). The basaltic units in the Lower Permian Kupukuziman and Kaipaizileike Formations in the Keping area, Tarim Basin; were the best exposure of the Permian basalt sequence in the basin. LA-ICP-MS U-Pb dating of zircon from the basal basaltic unit in the section gives an age of 291.9 ± 2.2 Ma (MSWD = 0.30, n = 17); this age, combined with previously published geochronological data, indicates that the basalts in the Tarim Basin were emplaced between 292 Ma and 272 Ma, with about 90% of the basalts being emplaced between 292 and 287 Ma. Basalts from the Keping area have high FeOT (10.8-18.6 wt.%), low Mg#s (0.26-0.60), and exhibit primitive mantle normalized patterns with positive Pb, P and Ti but negative Zr, Y and Ta anomalies. The basalts from both formations have similar 206Pb/204Pb (18.192-18.934), 207Pb/204Pb (15.555-15.598) and 208Pb/204Pb (38.643-38.793) ratios. The basalts also have high ɛSr(t) (45.7-62.1), low ɛNd(t) (-3.6 to -2.2) and low zircon ɛHf(t) (-4.84 to -0.65) values. These characteristics are typical of alkali basalts and suggest that the basalts within the Tarim Basin were derived from an OIB-type mantle source and interacted with enriched mantle (EMI-type) before emplacement. Rare earth element systematics indicate that the parental melts for the basalts were high-degree partial melts derived from garnet lherzolite mantle at the base of the lithosphere. Prior to emplacement, the Tarim Permian Basalts (TPB) underwent fractional crystallization and assimilated crustal material; the basalts were finally emplaced during crustal extension in an intra-plate setting. The wide distribution, deep source and high degree partial melting of the TPB was consistent with a mantle plume origin. The TPB and other coeval igneous

  10. Gem-bearing basaltic volcanism, Barrington, New South Wales: Cenozoic evolution, based on basalt K-Ar ages and zircon fission track and U-Pb isotope dating

    International Nuclear Information System (INIS)

    Based on basalt K-Ar and zircon fission track dating, Barrington shield volcano was active for 55 million years. Activity in the northeast, at 59 Ma, preceded more substantial activity between 55 and 51 Ma and more limited activity on western and southern flanks after 45 Ma. Eruptions brought up megacrystic gemstones (ruby, sapphire and zircon) throughout the volcanism, particularly during quieter eruptive periods. Zircon fission track dating (thermal reset ages) indicates gem-bearing eruptions at 57, 43, 38, 28 and 4-5 Ma, while U-Pb isotope SHRIMP dating suggests two main periods of zircon crystallisation between 60 and 50 Ma and 46-45 Ma. Zircons show growth and sector twinning typical of magmatic crystallisation and include low-U, moderate-U and high-U types. The 46 Ma high-U zircons exhibit trace and rare-earth element patterns that approach those of zircon inclusions in sapphires and may mark a sapphire formation time at Barrington. Two Barrington basaltic episodes include primary lavas with trace-element signatures suggesting amphibole/apatite-enriched lithospheric mantle sources. Other basalts less-enriched in Th, Sr, P and light rare-earth elements have trace-element ratios that overlap those of HIMU-related South Tasman basalts. Zircon and sapphire formation is attributed to crystallisation from minor felsic melts derived by incipient melting of amphibole-enriched mantle during lesser thermal activity. Ruby from Barrington volcano is a metamorphic type, and a metamorphic/metasomatic origin associated with basement ultramafic bodies is favoured. Migratory plate/plume paths constructed through Barrington basaltic episodes intersect approximately 80% of dated Palaeogene basaltic activity (65-30 Ma) along the Tasman margin (27-37 deg S) supporting a migratory plume-linked origin. Neogene Barrington activity dwindled to sporadic gem-bearing eruptions, the last possibly marking a minor plume trace. The present subdued thermal profile in northeastern New South

  11. Strategy for determination of geochemical reactivity in the Hanford basalts, southeastern Washington

    International Nuclear Information System (INIS)

    The geochemical reactivity of radionuclides or their analogues will be determined in basalt groundwater systems at the Hanford Site to assess its suitability for permanent disposal of high level radioactive waste. A combination of field and laboratory experiments are being designed to determine radionuclide sorption, kinetics of redox reactions, and retardation factors in basalt from a repository. Field testing requires that both single and paired borehole reactive tracer tests be carried out in basalt flow tops at a depth of about 1,000 meters. Special precautions are required to prevent atmospheric contamination of the borehole fluids which could affect the validity of results. Laboratory batch and column sorption testing on core materials collected before and after field tracer testing will be conducted to determine scale factors between laboratory and field sorption data obtained for a variety of key radionuclides

  12. Stress Corrosion Cracking of Basalt/Epoxy Composites under Bending Loading

    Science.gov (United States)

    Shokrieh, Mahmood M.; Memar, Mahdi

    2010-04-01

    The purpose of this research is to study the stress corrosion behavior of basalt/epoxy composites under bending loading and submerged in 5% sulfuric acid corrosive medium. There are limited numbers of research in durability of fiber reinforced polymer composites. Moreover, studies on basalt fibers and its composites are very limited. In this research, mechanical property degradation of basalt/epoxy composites under bending loading and submerged in acidic corrosive medium is investigated. Three states of stress, equal to 30%, 50% and 70% of the ultimate strength of composites, are applied on samples. High stress states are applied to the samples to accelerate the testing procedure. Mechanical properties degradation consists of bending strength, bending modulus of elasticity and fracture energy of samples are examined. Also, a normalized strength degradation model for stress corrosion condition is presented. Finally, microscopic images of broken cross sections of samples are examined.

  13. High renewable content sandwich structures based on flax-basalt hybrids and biobased epoxy polymers

    Science.gov (United States)

    Colomina, S.; Boronat, T.; Fenollar, O.; Sánchez-Nacher, L.; Balart, R.

    2014-05-01

    In the last years, a growing interest in the development of high environmental efficiency materials has been detected and this situation is more accentuated in the field of polymers and polymer composites. In this work, green composite sandwich structures with high renewable content have been developed with core cork materials. The base resin for composites was a biobased epoxy resin derived from epoxidized vegetable oils. Hybrid basalt-flax fabrics have been used as reinforcements for composites and the influence of the stacking sequence has been evaluated in order to optimize the appropriate laminate structure for the sandwich bases. Core cork materials with different thickness have been used to evaluate performance of sandwich structures thus leading to high renewable content composite sandwich structures. Results show that position of basalt fabrics plays a key role in flexural fracture of sandwich structures due to differences in stiffness between flax and basalt fibers.

  14. Bimodal basalt-rhyolite magmatism in the central and western Snake River Plain, Idaho and Oregon

    Science.gov (United States)

    McCurry, M.; Bonnichsen, B.; White, C.; Godchaux, M.M.; Hughes, S.S.

    1997-01-01

    The purpose of this trip is to examine Miocene to Pleistocene basalt and rhyolite flows, ignimbrites and hypabyssal intrusions in a transect from the western Snake River Plain graben across the older part of the Snake River Plain "hot-spot-track." The earlier, dominantly explosive rhyolitic phase of volcanism will be examined primarily in the Cassia Mountains, near Twin Falls, Idaho. The second day of the field trip will focus on the Graveyard Point intrusion, a strongly differentiated diabase sill in easternmost Oregon. This late Tertiary sill is well exposed from floor to roof in sections up to 150 m thick, and is an example of the type of solidified shallow magma chamber that may be present beneath some Snake River Plain basalt volcanoes. The field trip will conclude with an examination of the diverse styles of effusive and explosive basaltic volcanism in the central and western Snake River Plain.

  15. An assessment of the suitability of five overcoring techniques for stress determination in a jointed basalt

    International Nuclear Information System (INIS)

    Overcoring tests were conducted at the Near-Surface Test Facility (NSTF) using the US Bureau of Mines borehole deformation gauge, the C.S.I.R.O. hollow inclusion stress cell, the cast epoxy inclusion, the Lulea triaxial strain cell, and the C.S.I.R. ''doorstopper'' gauge to assess the suitability of each technique for in situ stress determination in a closely jointed basalt. This effort is in support of the Basalt Waste Isolation Project which is studying the feasibility of locating a nuclear waste repository in basalt. Testing at the NSTF provided information for the evaluation of overcoring techniques so that one or more can be selected to obtain in situ stress data at the reference repository horizon. Even though some problems were experienced, the borehole deformation gauge and doorstopper proved the most successful. 30 refs., 53 figs. 16 tabs

  16. The petrology and chemistry of basaltic fragments from the Apollo 11 soil - I

    Science.gov (United States)

    Beaty, D. W.; Hill, S. M. R.; Albee, A. L.; Ma, M.-S.; Schmitt, R. A.

    1979-01-01

    A study of basaltic fragments from the Apollo 11 bulk sample using instrumental neutron activation analysis, the petrographic microscope, and the electron microprobe is presented. The fragments include Group A, B2, and B3 basalts, of which two of the Group A samples are vitrophyres with bulk compositions similar to the crystalline high-K rocks which crystallized under different physical conditions and represent a second high-K cooling unit. The B2 samples relate to each other through ilmenite fractionation, and the B3 samples relate through olivine fractionation; it is concluded that the B2 samples have an anomalously high La/K ratio and may have generated in the same source region as the Group D basalts.

  17. Preliminary K/Ar geochronology of the Crater Basalt volcanic field (CBVF, northern Patagonia

    Directory of Open Access Journals (Sweden)

    Z. Pécskay

    2007-03-01

    Full Text Available The Crater Basalt volcanic field is one of the Quaternary intraplate basaltic fields in northern Patagonia. A systematic geological, volcanological and geochronological study of CBVF indicates a multistage history of eruptions of basaltic volcanoes. K/Ar dating, using whole rock samples shows that the measured analytical ages are fully consistent with the available stratigraphic control. The radiometric ages fall into three distinct, internally consistent age groups, which give evidence that there were at least three major episodes of volcanic activity, at about 1.0 Ma, 0.6 Ma and 0.3 Ma ago. The age differences appear to be just significant, even although less than 10 % radiogenic argon was found in the isotope analysis of whole rock samples.

  18. Structure and density of basaltic melts at mantle conditions from first-principles simulations

    Science.gov (United States)

    Bajgain, Suraj; Ghosh, Dipta B.; Karki, Bijaya B.

    2015-10-01

    The origin and stability of deep-mantle melts, and the magmatic processes at different times of Earth's history are controlled by the physical properties of constituent silicate liquids. Here we report density functional theory-based simulations of model basalt, hydrous model basalt and near-MORB to assess the effects of iron and water on the melt structure and density, respectively. Our results suggest that as pressure increases, all types of coordination between major cations and anions strongly increase, and the water speciation changes from isolated species to extended forms. These structural changes are responsible for rapid initial melt densification on compression thereby making these basaltic melts possibly buoyantly stable at one or more depths. Our finding that the melt-water system is ideal (nearly zero volume of mixing) and miscible (negative enthalpy of mixing) over most of the mantle conditions strengthens the idea of potential water enrichment of deep-mantle melts and early magma ocean.

  19. Immense vent complex marks flood-basalt eruption in a wet, failed rift: Coombs Hills, Antarctica

    Science.gov (United States)

    White, J. D. L.; McClintock, M. K.

    2001-10-01

    Large lava effusions can have impressive explosive antecedents. Although our picture of flood basalt is overwhelmingly effusive, phreatomagmatic eruptions have preceded quiet effusion of some flood basalts and reflect the same influence of vent architecture and hydrology on eruptive style as seen for small-volume eruptions. The scale of phreatomagmatic deposits associated with flood basalts can be huge. At Coombs Hills a vast, but otherwise typical, phreatomagmatic vent complex is exposed over more than 25 km2, and its features are interpreted to reflect processes of tephra-jet eruptions with diatreme development. Similar vent complexes are probably the source of laharic deposits reported elsewhere in the Transantarctic Mountains and in the Karoo province of South Africa.

  20. Modeling of the Sedimentary Interbedded Basalt Stratigraphy for the Idaho National Laboratory Probabilistic Seismic Hazard Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Suzette Payne

    2007-08-01

    This report summarizes how the effects of the sedimentary interbedded basalt stratigraphy were modeled in the probabilistic seismic hazard analysis (PSHA) of the Idaho National Laboratory (INL). Drill holes indicate the bedrock beneath INL facilities is composed of about 1.1 km of alternating layers of basalt rock and loosely consolidated sediments. Alternating layers of hard rock and “soft” loose sediments tend to attenuate seismic energy greater than uniform rock due to scattering and damping. The INL PSHA incorporated the effects of the sedimentary interbedded basalt stratigraphy by developing site-specific shear (S) wave velocity profiles. The profiles were used in the PSHA to model the near-surface site response by developing site-specific stochastic attenuation relationships.

  1. Modeling of the Sedimentary Interbedded Basalt Stratigraphy for the Idaho National Laboratory Probabilistic Seismic Hazard Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Suzette Payne

    2006-04-01

    This report summarizes how the effects of the sedimentary interbedded basalt stratigraphy were modeled in the probabilistic seismic hazard analysis (PSHA) of the Idaho National Laboratory (INL). Drill holes indicate the bedrock beneath INL facilities is composed of about 1.1 km of alternating layers of basalt rock and loosely consolidated sediments. Alternating layers of hard rock and “soft” loose sediments tend to attenuate seismic energy greater than uniform rock due to scattering and damping. The INL PSHA incorporated the effects of the sedimentary interbedded basalt stratigraphy by developing site-specific shear (S) wave velocity profiles. The profiles were used in the PSHA to model the near-surface site response by developing site-specific stochastic attenuation relationships.

  2. Experimental partitioning of rare earth elements and scandium among armalcolite, ilmenite, olivine and mare basalt liquid

    Science.gov (United States)

    Irving, A. J.; Merrill, R. B.; Singleton, D. E.

    1978-01-01

    An experimental study was carried out to measure partition coefficients for two rare-earth elements (Sm and Tm) and Sc among armalcolite, ilmenite, olivine and liquid coexisting in a system modeled on high-Ti mare basalt 74275. This 'primitive' sample was chosen for study because its major and trace element chemistry as well as its equilibrium phase relations at atmospheric pressure are known from previous studies. Beta-track analytical techniques were used so that partition coefficients could be measured in an environment whose bulk trace element composition is similar to that of the natural basalt. Partition coefficients for Cr and Mn were determined in the same experiments by microprobe analysis. The only equilibrium partial melting model appears to be one in which ilmenite is initially present in the source region but is consumed by melting before segregation of the high-Ti mare basalt liquid from the residue.

  3. Thermal control of low-pressure fractionation processes. [in basaltic magma solidification

    Science.gov (United States)

    Usselman, T. M.; Hodge, D. S.

    1978-01-01

    Thermal models detailing the solidification paths for shallow basaltic magma chambers (both open and closed systems) were calculated using finite-difference techniques. The total solidification time for closed chambers are comparable to previously published calculations; however, the temperature-time paths are not. These paths are dependent on the phase relations and the crystallinity of the system, because both affect the manner in which the latent heat of crystallization is distributed. In open systems, where a chamber would be periodically replenished with additional parental liquid, calculations indicate that the possibility is strong that a steady-state temperature interval is achieved near a major phase boundary. In these cases it is straightforward to analyze fractionation models of the basaltic liquid evolution and their corresponding cumulate sequences. This steady thermal fractionating state can be invoked to explain large amounts of erupted basalts of similar composition over long time periods from the same volcanic center and some rhythmically layered basic cumulate sequences.

  4. Post-Impact Mechanical Characterisation of Glass and Basalt Woven Fabric Laminates

    Science.gov (United States)

    De Rosa, Igor M.; Marra, Francesco; Pulci, Giovanni; Santulli, Carlo; Sarasini, Fabrizio; Tirillò, Jacopo; Valente, Marco

    2012-06-01

    Two woven fabric laminates, one based on basalt fibres, the other on E-glass fibres, as a reinforcement for vinylester matrix, were compared in terms of their post-impact performance. With this aim, first the non-impacted specimens were subjected to interlaminar shear stress and flexural tests, then flexural tests were repeated on laminates impacted using a falling weight tower at three impact energies (7.5, 15 and 22.5J). Tests were monitored using acoustic emission analysis of signal distribution with load and with distance from the impact point. The results show that the materials have a similar damage tolerance to impact and also their post-impact residual properties after impact do not differ much, with a slight superiority for basalt fibre reinforced laminates. The principal difference is represented by the presence of a more extended delamination area on E-glass fibre reinforced laminates than on basalt fibre reinforced ones.

  5. The Bowen-Fenner Debate Revisited: A Review of Basalt Crystal Fractionation and the Generation of Andesite

    Science.gov (United States)

    Conrey, R. M.

    2002-12-01

    The Bowen-Fenner debate over the nature of basalt crystal fractionation is still unresolved. Bowen's classic 1928 book detailed his basalt-andesite-rhyolite fractionation scheme, whereas Fenner emphasized the evidence for Fe-enrichment during most basalt crystallization, thus anticipating discovery of the Skaergaard. In the 1940's Bowen suggested only wet basalt generates common andesite. To address this debate MELTS simulations were performed with near-constant parents but varied water contents from 0-4 wt per cent. For comparison, data were compiled from mid-ocean ridge (MORB), back-arc basin (BABB), and arc basalts. There is a strong correlation between empirical fractionation patterns and the simulations. Dry basaltic magma exemplified by MORB shows fractionation patterns controlled by early plagioclase crystallization, whereas nearly all wet arc basaltic magmas have patterns controlled by crystallization of mafic minerals, with the later onset of highly calcic plagioclase. BABB have fractionation patterns between those two extremes. The fundamental antithetic behavior of Al and Fe during basalt crystal fractionation due to the sensitive control over plagioclase crystallization by water is completely obscured by the use of Harker and AFM diagrams. Mafic arc basalts which show evidence for significant crystallization of magnetite are largely lacking - most arc basalt fractionation patterns are consistent with 2-3 per cent H2O in the primitive melt and oxygen fugacity near the NNO buffer. A few mafic arc volcanoes have steep increases in Al content or slightly declining Fe content with only slight increases in FeO*/MgO suggestive of significant magnetite crystallization. Magma at these centers must be somewhat more hydrous and/or oxidized than is the normal case. Arc basalt clinopyroxene compositions support the inference that common high-alumina basalt (HAB) is a derivative magma, as empirical and experimental data, and MELTS simulations, all show coupled

  6. Hydrochemistry and hydrogeologic conditions within the Hanford Site upper basalt confined aquifer system

    International Nuclear Information System (INIS)

    As part of the Hanford Site Ground-Water Surveillance Project, Flow System Characterization Task. Pacific Northwest Laboratory examines the potential for offsite migration of contamination within the upper basalt confined aquifer system for the US Department of Energy (DOE). As part of this activity, groundwater samples were collected over the past 2 years from selected wells completed in the upper Saddle Mountains Basalt. The hydrochemical and isotopic information obtained from these groundwater samples provides hydrologic information concerning the aquifer-flow system. Ideally, when combined with other hydrologic property information, hydrochemical and isotopic data can be used to evaluate the origin and source of groundwater, areal groundwater-flow patterns, residence and groundwater travel time, rock/groundwater reactions, and aquifer intercommunication for the upper basalt confined aquifer system. This report presents the first comprehensive Hanford Site-wide summary of hydrochemical properties for the upper basalt confined aquifer system. This report provides the hydrogeologic characteristics (Section 2.0) and hydrochemical properties (Section 3.0) for groundwater within this system. A detailed description of the range of the identified hydrochemical parameter subgroups for groundwater in the upper basalt confined aquifer system is also presented in Section 3.0. Evidence that is indicative of aquifer contamination/aquifer intercommunication and an assessment of the potential for offsite migration of contaminants in groundwater within the upper basalt aquifer is provided in Section 4.0. The references cited throughout the report are given in Section 5.0. Tables that summarize groundwater sample analysis results for individual test interval/well sites are included in the Appendix

  7. Dynamics of basaltic glass dissolution - Capturing microscopic effects in continuum scale models

    Science.gov (United States)

    Aradóttir, E. S. P.; Sigfússon, B.; Sonnenthal, E. L.; Björnsson, G.; Jónsson, H.

    2013-11-01

    The method of 'multiple interacting continua' (MINC) was applied to include microscopic rate-limiting processes in continuum scale reactive transport models of basaltic glass dissolution. The MINC method involves dividing the system up to ambient fluid and grains, using a specific surface area to describe the interface between the two. The various grains and regions within grains can then be described by dividing them into continua separated by dividing surfaces. Millions of grains can thus be considered within the method without the need to explicity discretizing them. Four continua were used for describing a dissolving basaltic glass grain; the first one describes the ambient fluid around the grain, while the second, third and fourth continuum refer to a diffusive leached layer, the dissolving part of the grain and the inert part of the grain, respectively. The model was validated using the TOUGHREACT simulator and data from column flow through experiments of basaltic glass dissolution at low, neutral and high pH values. Successful reactive transport simulations of the experiments and overall adequate agreement between measured and simulated values provides validation that the MINC approach can be applied for incorporating microscopic effects in continuum scale basaltic glass dissolution models. Equivalent models can be used when simulating dissolution and alteration of other minerals. The study provides an example of how numerical modeling and experimental work can be combined to enhance understanding of mechanisms associated with basaltic glass dissolution. Column outlet concentrations indicated basaltic glass to dissolve stoichiometrically at pH 3. Predictive simulations with the developed MINC model indicated significant precipitation of secondary minerals within the column at neutral and high pH, explaining observed non-stoichiometric outlet concentrations at these pH levels. Clay, zeolite and hydroxide precipitation was predicted to be most abundant within

  8. Indigenous nitrogen in the Moon: Constraints from coupled nitrogen-noble gas analyses of mare basalts

    Science.gov (United States)

    Füri, Evelyn; Barry, Peter H.; Taylor, Lawrence A.; Marty, Bernard

    2015-12-01

    Nitrogen and noble gas (Ne-Ar) abundances and isotope ratios, determined by step-wise CO2 laser-extraction, static-mass spectrometry analysis, are reported for bulk fragments and mineral separates of ten lunar mare basalts (10020, 10057, 12008, 14053, 15555, 70255, 71557, 71576, 74255, 74275), one highland breccia (14321), and one ferroan anorthosite (15414). The mare basalt sub-samples 10057,183 and 71576,12 contain a large amount of solar noble gases, whereas neon and argon in all other samples are purely cosmogenic, as shown by their 21Ne/22Ne ratios of ≈0.85 and 36Ar/38Ar ratios of ≈0.65. The solar-gas-free basalts contain a two-component mixture of cosmogenic 15N and indigenous nitrogen (Mare basalt 74255 and the olivine fraction of 15555,876 record the smallest proportion of 15Ncosm; therefore, their δ15 N values of -0.2 to + 26.7 ‰ (observed at the low-temperature steps) are thought to well represent the isotopic composition of indigenous lunar nitrogen. However, δ15 N values ≤ - 30 ‰ are found in several basalts, overlapping with the isotopic signature of Earth's primordial mantle or an enstatite chondrite-like impactor. While the lowest δ15 N values allow for nitrogen trapped in the Moon's interior to be inherited from the proto-Earth and/or the impactor, the more 15N-enriched compositions require that carbonaceous chondrites provided nitrogen to the lunar magma ocean prior to the solidification of the crust. Since nitrogen can efficiently be incorporated into mafic minerals (olivine, pyroxene) under oxygen fugacities close to or below the iron-wustite buffer (Li et al., 2013), the mare basalt source region is likely characterized by a high nitrogen storage capacity. In contrast, anorthosite 15414 shows no traces of indigenous nitrogen, suggesting that nitrogen was not efficiently incorporated into the lunar crust during magma ocean differentiation.

  9. High-level waste-basalt interactions. Annual progress report, February 1, 1977--September 30, 1977

    International Nuclear Information System (INIS)

    Commercial radioactive waste can be placed under ground in a basalt repository to contain significant amounts of radioactive decay heat for the first hundred or so years, which constitutes the ''thermal period'' of waste isolation, if the feasibility is determined that a basalt geology is a suitable medium for storage of radioactive wastes. Several physical-chemical changes analogous to natural geochemical processes can occur in and around this repository during the thermal period. The waste canister can act as a heat source and cause changes in the mineralogy and properties of the surrounding basalts. Geochemically, this is ''contact metamorphism.'' This phenomenon needs to be investigated because it could affect the behavior of the basalt with regard to migration of long-lived radionuclides away from the immediate repository. It is well known that even the relatively low-grade hydrothermal conditions possible in the repository (temperatures up to 400 degrees Centigrade; pressures up to 300 bars) can cause extensive modifications in rocks and minerals. At the end of the thermal period, the residue of the original waste plus the waste-basalt interaction products would constitute the actual waste form (or ''source term'') subject to the low-temperature leaching and migration processes under investigation in other laboratories. During the last eight months of fiscal year 1977, a program was initiated at The Pennsylvania State University which had as its objective the determination of the nature and implication of any chemical or mineralogical changes in, or interactions between, each candidate radioactive waste form and representative Columbia River Basalt under the various relevant repository conditions during the thermal period. Results of these investigations are given

  10. Asthenosphere versus lithosphere as possible sources for basaltic magmas erupted during formation of the Red Sea

    International Nuclear Information System (INIS)

    Representative basalts from the axial trough of the Red Sea and from volcanic fields of the Arabian Peninsula ranging in composition from N-type MORB to basanite and in age from Early Miocene to Recent show a limited variation in their isotopic compositions: 87Sr/86Sr = 0.70240-0.70361, 206Pb/204Pb = 18.040-19.634, 207Pb/204Pb = 15.496-15.666, 208Pb/204Pb = 37.808-39.710, 143Nd/144Nd = 0.513194-0.512670. There is a poorly constrained correlation between chemical composition and isotope ratios: with increasing alkalinity, Sr and Pb isotope ratios increase and the Nd isotope ratio tends to decrease. In Pb isotope variation diagrams most of the basalts plot significantly above the NHRLs, irrespective of tectonic setting, i.e. thickness of underlying crust and/or lithosphere. MORBs from the axial trough of the Red Sea have higher Pb isotope ratios for a given 87Sr/86Sr than MORBs from the Indian Ocean ridges, including the Carlsberg Ridge. It is therefore suggested that both spreading ridges tap different convective systems in the asthenosphere. The tectonic setting of the basalts is reflected in their Nd-Sr isotope characteristics. Basalts from areas where the continental lithosphere is drastically thinned or absent (i.e. Red Sea axial trough and coastal plain, Afar) plot along a reference line defined by N-type MORB and Tristan da Cunha. Basalts erupted in areas with Pan-African crust of normal thickness and moderately thinned lithospheric mantle (i.e. rift shoulder) are characterized by relative low 143Nd/144Nd ratios and plot below the reference line towards an EM I component which is also found in the subcontinental lithospheric mantle. These differences in the Nd-Sr isotopic compositions of the basalts are independent of bulk-rock chemistry and are therefore controlled by tectonic setting alone. (orig./WL)

  11. Hydrologic bibliography of the Columbia River basalts in Washington with selected annotations

    International Nuclear Information System (INIS)

    The objective of this compilation is to present a comprehensive listing of the published, unpublished, and open file references pertaining to the surface and subsurface hydrology of the Columbia River basalts within the State of Washington and is presented in support of Rockwell's hydrologic data compilation effort for the Basalt Waste Isolation Program. A comprehensive, annotated bibliography of the Pasco Basin (including the Hanford Site) hydrology has been prepared for Rockwell as part of the Pasco Basin hydrology studies. In order to avoid unnecessary duplication, no effort was made to include a complete list of bibliographic references on Hanford in this volume

  12. Lithospheric evolution of the Northern Arabian Shield: Chemical and isotopic evidence from basalts, xenoliths and granites

    Science.gov (United States)

    Stein, M.

    1988-01-01

    The evolution of the upper-mantle and the lower-crust (the conteinental lithosphere), is the area of Israel and Sinai was studied, using the chemical composition and the Nd-Sr isotopic systematics from mantle and crustal nodules, their host basalts, and granites. The magmatism and the metasomatism making the lithosphere are related to uprise of mantle diapirs in the uppermost mantle of the area. These diapirs heated the base of the lithosphere, eroded, and replaced it with new hot material. It caused a domal uplift of the lithosphere (and the crust). The doming resulted in tensional stresses that in turn might develop transport channels for the basalt.

  13. Evolution of the basalts from three back-arc basins of southwest Pacific

    Digital Repository Service at National Institute of Oceanography (India)

    Mudholkar, A.V.; Paropkari, A.L.

    with X-ray #uorescence spectrometer. Internal standards were used for calibration of the equipment and for checking the accuracy of the data. The error was found to be within $3}5% for major and trace elements. Thin sections of basalts were prepared... ELSC. From the CLSC we studied four basalts from a single site (2231-2, -3, -6, -8). Methodology The 21st cruise of R/< Mstislav Keldysh (with two Mir submersibles on board) was organized to investigate tec- tonic evolution and metallogeny of three...

  14. Strengthening of reinforced concrete beams with basalt-based FRP sheets: An analytical assessment

    Science.gov (United States)

    Nerilli, Francesca; Vairo, Giuseppe

    2016-06-01

    In this paper the effectiveness of the flexural strengthening of RC beams through basalt fiber-reinforced sheets is investigated. The non-linear flexural response of RC beams strengthened with FRP composites applied at the traction side is described via an analytical formulation. Validation results and some comparative analyses confirm soundness and consistency of the proposed approach, and highlight the good mechanical performances (in terms of strength and ductility enhancement of the beam) produced by basalt-based reinforcements in comparison with traditional glass or carbon FRPs.

  15. Sr Isotopic Evidence on the Spilitic Degradation of the Deccan Basalt

    Indian Academy of Sciences (India)

    K V Subbarao

    2000-03-01

    Similar Sr isotopic ratios (∼0.7055) for the tholeiite-spilite flow unit and the associated mineral phases, of Bombay (Deccan Traps) provide a direct evidence for the spilitic degradation of tholeiite. In contrast, a dramatic increase in the rare earth elements (REE) from basalt to spilite is rather puzzling as rare earths are considered to be relatively immobile. The geochemistry thus suggests that the process of spilitization is due to the reaction with a complex fluid having identical Sr-isotopic composition as that of the basaltic magma - thereby masking the details of the mixing process.

  16. Chromium isotope fractionation during oxidative weathering of a modern basaltic weathering profile

    DEFF Research Database (Denmark)

    D'Arcy, Joan Mary; Døssing, Lasse Nørbye; Frei, Robert

    fractionate under both reducing and oxidizing conditions [1, 2]. Recent studies on d53Cr isotopes in laterite soils show that oxidative weathering of Cr-bearing rocks is accompanied by an isotopic fractionation, where by the lighter isotopes are retained in the residual soil and the heavier isotope is...... enriched in local runoff [1]. This study aims to quantify the stable Cr isotope composition of two modern basaltic weathering profiles, to help better understand the processes that oxidize inert Cr (III) to toxic Cr (VI). We sampled basaltic weathering profiles and associated river waters from areas of two...

  17. Extreme magnesium isotope fractionation during bauxite formation on the Columbia River Basalts

    Science.gov (United States)

    Liu, X.; Teng, F.; Rudnick, R. L.; McDonough, W. F.; Cummings, M. L.

    2012-12-01

    The behavior of magnesium isotopes during intense weathering of continental basalt is investigated by analyses of two ~10 m deep drill cores through bauxite developed on Columbia River Basalts (CRBs) in western Oregon and Washington, United States. XRD analyses reveal that these cores consist of gibbsite, hematite, +/- halloysite, kaolinite, goethite and maghemite; quartz, which is not present in fresh basalt, occurs only at the top of the cores and its abundance decreases progressively with depth; no quartz is observed below 5 m depth in either core. Both profiles display strong Mg depletion (up to 99%) relative to fresh basalt and one profile shows re-enrichment of Mg near the surface. δ26Mg values in bauxites are extremely high (up to +1.7) relative to the fresh basalts, which have mantle-like δ26Mg of -0.24 ± 0.07. The Mg isotopic fractionation in these bauxites is unlikely to be caused by kinetic fractionation via chemical diffusion (as suggested for lithium isotopes for a different weathering profile by Teng et al. (1)) because Richter et al. (2) found no measureable Mg isotopic fractionation associated with Mg diffusion in water. Moreover, due to the intense weathering, Mg isotopic fractionation in these drill cores should not be influenced by dissolution of basalts. Therefore, it is likely that the observed extreme Mg isotopic fractionation is associated with secondary mineral formation. However, δ26Mg tends to lower values towards the surface in both cores, opposite the trend that is expected to be produced by progressive leaching of the basalt accompanied by secondary mineral formation. Both the presence of quartz and less radiogenic Nd isotopic compositions at the tops of the profiles suggest that eolian material has been added to the top few meters of these weathering profiles, causing the Mg isotopic composition to be lighter at the surface. Moreover, both Mg concentration and δ26Mg in bauxites influenced by eolian addition show correlations with

  18. Review of the upper Cenozoic stratigraphy overlying the Columbia River Basalt Group in western Idaho

    International Nuclear Information System (INIS)

    This report is a synthesis of information currently available on the rocks that stratigraphically overlie the Columbia River Basalt Group in Idaho. The primary objective is to furnish a brief but comprehensive review of the literature available on upper Cenozoic rocks in western Idaho and to discuss their general stratigraphic relationships. This study also reviews the derivation of the present stratigraphy and notes weaknesses in our present understanding of the geology and the stratigraphy. This report was prepared in support of a study to evaluate the feasibility of nuclear waste storage in the Columbia River Basalt Group of the Pasco Basin, Washington

  19. INAA and RNAA of an Apollo-17 lunar mare basalt sample for 36 elements

    International Nuclear Information System (INIS)

    Thirty six elements, including all the fourteen naturally occurring lanthanides, were determined in an Apollo-17 lunar mare basalt sample by means of INAA and RNAA. Total amount of sample used was 62.1 mg. A detailed radiochemical separation scheme was established. Chemical yields for most of the thirty six elements tested are quantitative. Accuracy of the results was verified by parallel analysis of USGS W-1. The concentration data for most elements are in good agreement with literature values. C1 chondrite-normalized REE concentrations show a typical lunar mare basalt pattern. (author)

  20. Argon-40: Excess in submarine pillow basalts from Kilauea Volcano, Hawaii

    Science.gov (United States)

    Brent, Dalrymple G.; Moore, J.G.

    1968-01-01

    Submarine pillow basalts from Kilauea Volcano contain excess radiogenic argon-40 and give anomalously high potassium-argon ages. Glassy rims of pillows show a systematic increase in radiogenic argon-40 with depth, and a pillow from a depth of 2590 meters shows a decrease in radiogenic argon-40 inward from the pillow rim. The data indicate that the amount of excess radiogenic argon-40 is a direct function of both hydrostatic pressure and rate of cooling, and that many submarine basalts are not suitable for potassium-argon dating.

  1. Microbial communities in recent and 10 - 28 Ma ocean floor basalt (ODP Leg 187)

    Science.gov (United States)

    Lysnes, K.; Steinsbu, B. O.; Einen, J.; Thorseth, I. H.; Pedersen, R. B.; Torsvik, T.

    2003-04-01

    Previous studies have shown that microbial communities are harboring ocean crust basalt (e.g., Thorseth et al. 1995). The non-hydrothermal regions of ocean ridges are largely unstudied with respect to microbial diversity and physiology. In the present study, the microbial communities resident in samples of recent (microbial diversity and to compare the endolithic microbial communities in seafloor samples (Arctic Ridges) with subsurface samples (ODP Leg 187) by molecular biology techniques. To monitor possible contamination samples of sediment and seawater, treated in the same manner as the basalt samples, served as controls. Polymerase chain reaction -- denaturing gradient gel electrophoresis (PCR -- DGGE) were used to amplify fragments of 16S rRNA genes and to separate individual DNA sequences, corresponding to different species and strains of Bacteria and Archaea in the samples. Relative similarity indices were calculated from DGGE banding patterns using Jaccard's algorithm, and species richness was estimated using Shannon's index. Furthermore, individual DNA bands were excised from the gel and sequenced to evaluate the phylogenetic affiliation of the endolithic microbes. Shannon indices show that the species richness of microbial communities in basalt is higher for seafloor samples (Arctic Ridges) than for subsurface samples (Southeast Indian Ridge). The microbial population in the Arctic Ridge basalt samples affiliates with ten major lineages of the domain Bacteria and 1 major lineage of Archaea. Bacteria in the ODP Leg 187 basalt samples affiliate with six major lineages of the domain Bacteria, whereas no archaeal sequences were retrieved from these samples. Many sequences from both areas appear to be unaffiliated with any previously isolated microbes. The uncultured green nonsulfur bacterium Chloroflexales Arctic 96BD-6, and the three gamma proteobacteria Acinetobacter junii, Pseudoalteromonas sp., and Shewanella frigidimarina affiliate with sequences from

  2. The decompression of basaltic magma into a sub-surface repository

    OpenAIRE

    Bokhove, O.; Woods, A. W.

    2002-01-01

    We examine the ascent of volatile-rich basaltic magma through a vertical dike that intersects a horizontal tunnel of comparable cross-sectional area to the dike and located 300 $m$ below the surface and initially filled with air at atmospheric pressure. This process is a simplified representation of some aspects of the possible interaction of a basaltic fissure eruption with a man-made tunnel, as part of a risk assessment for the proposed high level waste repository at Yucca Mountain, Nevada,...

  3. Origin of arc-like continental basalts: Implications for deep-Earth fluid cycling and tectonic discrimination

    Science.gov (United States)

    Wang, Xuan-Ce; Wilde, Simon A.; Xu, Bei; Pang, Chong-Jin

    2016-09-01

    Continental basalts generally display enrichment of fluid-mobile elements and depletion of high-field-strength elements, similar to those that evolved in the subduction environment, but different from oceanic basalts. Based on the continental flood basalt database for six large igneous provinces, together with rift-related basalt data from the Basin and Range Province, this study aimed to test the validity of geochemical tectonic discrimination diagrams in distinguishing arc-like intra-continental basalts from arc basalts and to further investigate the role of deep-Earth water cycling in producing arc-like signatures in large-scale intra-continental basalts. Our evaluation shows that arc-like intra-continental basalts can be distinguished from arc basalts by integrating the following factors: (1) the FeO, MgO, and Al2O3 concentrations of the primary melt; (2) Tisbnd V, Zrsbnd Zr/Y, Zrsbnd Ti, and Ti/Vsbnd Zr/Smsbnd Sr/Nd discrimination diagrams; (3) the coexistence of arc-like and OIB-like subtype basalts within the same province; (4) primitive mantle-normalized trace element distribution patterns. The similarity of enrichment in fluid-mobile elements (Ba, Rb, Sr, U, and K) between arc-like and true arc basalts suggests the importance of water flux melting in producing arc-like signatures in continental basalts. Experimentally determined liquid lines of descent (LLD) imply high magma water concentrations for continental flood basalts (CFBs) and the Basin and Range basalts. Furthermore, estimates based on the Al2O3-LLD method indicates 4.0-5.0 wt% pre-eruptive magma H2O concentration for CFBs and the Basin and Range basalts. The tight relationships between H2O/Ce and Ba/La, Ba/Nb and Rb/Nb based on global arc basalt data were further used to estimate the primary H2O concentrations. With the exception of the Emeishan CFBs (mainly containing 4.0-5.6 wt% H2O), all other CFBs investigated have similar estimated primary H2O contents, with values ranging from 1.0 to 2

  4. Geochemistry of Paraná-Etendeka basalts from Misiones, Argentina: Some new insights into the petrogenesis of high-Ti continental flood basalts

    Science.gov (United States)

    Rämö, O. Tapani; Heikkilä, Pasi A.; Pulkkinen, Arto H.

    2016-04-01

    The Early Cretaceous (˜135-131 Ma) Paraná-Etendeka continental flood basalts, preserved in bulk in the Paraná basin of southern Brazil and vicinity, have been divided into low-Ti and high-Ti types that govern the southern and northern halves of the basin, respectively. We have examined a new sample set from the southern margin of the northern high-Ti segment of Paraná basalts in Misiones, northeastern Argentina. These basalts are strongly to moderately enriched in TiO2 (2-4 wt.%), have relatively high Ti/Y (300-500), low MgO (3.5-6.5 wt.%), and high Fe (FeO(tot) 12-14 wt.%) and belong to the Pitanga and Paranapanema magma types of Peate et al. (1992). Nd and Sr isotope compositions are quite unvarying with ɛNd (at 133 Ma) values of -4.6 to -3.6 and initial 87Sr/86Sr of 0.7054-0.7059 and show no variation with fractionation. Compared to high-Ti lavas in the central and northern parts of the Paraná high-Ti basalt segment, the lavas from Misiones are similar to those in the northeastern magin of the basin but less radiogenic in initial Nd isotope composition than those in the central part. This variation probably reflects mixed EM1-EM2 source components in the sublithospheric mantle. A polybaric melt model of a sublithospheric mantle source at the garnet lherzolite-spinel lherzolite transition is compatible with the observed Ti budget of the Pitanga and Paranapanema lavas, regardless of the Nd isotope composition of their purported source.

  5. Geochemistry and stratigraphic correlation of basalt lavas beneath the Idaho Chemical Processing Plant, Idaho National Engineering Laboratory

    Science.gov (United States)

    Reed, M.F.; Bartholomay, R.C.; Hughes, S.S.

    1997-01-01

    Thirty-nine samples of basaltic core were collected from wells 121 and 123, located approximately 1.8 km apart north and south of the Idaho Chemical Processing Plant at the Idaho National Engineering Laboratory. Samples were collected from depths ranging from 15 to 221 m below land surface for the purpose of establishing stratigraphic correlations between these two wells. Elemental analyses indicate that the basalts consist of three principal chemical types. Two of these types are each represented by a single basalt flow in each well. The third chemical type is represented by many basalt flows and includes a broad range of chemical compositions that is distinguished from the other two types. Basalt flows within the third type were identified by hierarchical K-cluster analysis of 14 representative elements: Fe, Ca, K, Na, Sc, Co, La, Ce, Sm, Eu, Yb, Hf, Ta, and Th. Cluster analyses indicate correlations of basalt flows between wells 121 and 123 at depths of approximately 38-40 m, 125-128 m, 131-137 m, 149-158 m, and 183-198 m. Probable correlations also are indicated for at least seven other depth intervals. Basalt flows in several depth intervals do not correlate on the basis of chemical compositions, thus reflecting possible flow margins in the sequence between the wells. Multi-element chemical data provide a useful method for determining stratigraphic correlations of basalt in the upper 1-2 km of the eastern Snake River Plain.

  6. Statistical factor analysis technique for characterizing basalt through interpreting nuclear and electrical well logging data (case study from Southern Syria)

    International Nuclear Information System (INIS)

    Factor analysis technique is proposed in this research for interpreting the combination of nuclear well logging, including natural gamma ray, density and neutron-porosity, and the electrical well logging of long and short normal, in order to characterize the large extended basaltic areas in southern Syria. Kodana well logging data are used for testing and applying the proposed technique. The four resulting score logs enable to establish the lithological score cross-section of the studied well. The established cross-section clearly shows the distribution and the identification of four kinds of basalt which are hard massive basalt, hard basalt, pyroclastic basalt and the alteration basalt products, clay. The factor analysis technique is successfully applied on the Kodana well logging data in southern Syria, and can be used efficiently when several wells and huge well logging data with high number of variables are required to be interpreted. - Highlights: • Statistical factor analysis technique is proposed for interpreting nuclear and electrical well logging data in basaltic environment. • New rotated scored logs are established and interpreted at the light of available geological data. • The established score lithological cross-section differentiates between four different kinds of basalt

  7. 40Ar/39Ar total gas ages of basalts from Notera-3 well, Hula Valley, Dead Sea Rift

    International Nuclear Information System (INIS)

    Dating of basalts penetrated in the Notera-3 well in the Hula Valley by the 40Ar/39Ar method in a single, gas extraction reveals a relatively consistent pattern in the section. Using these data a refinement of the stratigraphy for the volcanic units within the Hula Valley and the timing of its development is obtained. Basalts from the depth of 500-1100m have an age of 1.4-1.1 m.y. and are correlated with the Dalwe Basalt known from the slopes of the Golan Heights, with the Yarda Basalt in the Korazim Block, and with the Hasbani Basalt in the southern Lebanon. Basalt from the 1100-1600m interval have an age of 2.7 m.y. and are correlated with the Mechki Basalt in the southern Lebanon and in the Upper Galilee. Basalt from the 1600-2418m interval range in age from 3.2 to 4.1 m.y. and are correlated with the cover basalt as known in the Golan Heights and the Galilee. At a depth of 2427m, a Miocene basalt was encountered (age 8.8 m.y.). Such basalt have not been encountered previously north of the Lower Galilee. The lack of basalts and/or sediments having ages of 8.8-4.1 m.y. indicates that the Hula area was structurally relatively high at that time; thus prior to the Cover Basalt as known in the Hula area did not serve as a morphologic depression. Significant subsidence of the Hula Valley is recognized since Cover Basalt time. It seems that the tectonic phase which led to the formation of the Hula depression as one of the rhomb-shaped garbens along the Rift was initiated 4 m.y. ago. The rate of subsidence of the Hula Valley since its formation is 0.5-0.7 mm/y, which is similar to that estimated from other areas along the Dead Sea Rift. (author)

  8. Performance allocation traceable to regulatory criteria as applied to site characterization work at the Basalt Waste Isolation Project

    International Nuclear Information System (INIS)

    The Basalt Waste Isolation Project has developed a method for defining in detail the work required to demonstrate the feasibility of emplacing and providing for the safe isolation of nuclear wastes in a repository in the deep basalts at the Hanford Site near Richland, Washington. Criteria analysis allows the identification of areas of significant technical uncertainty or controversy that can be highlighted as issues. A preliminary analysis has been conducted, which, by identifying key radionuclides and allocating performance among the multiple barriers in a repository constructed in a basalt, allows the design and development testing activities at the Basalt Waste Isolation Project to be put into perspective. Application of sophisticated uncertainty analysis techniques will allow refinements in the analysis to be made and to further guide characterization and testing activities. Preliminary results suggest that a repository constructed in basalt will provide for the safe isolation of nuclear wastes in a cost-effective and reliable manner with a high degree of confidence

  9. A Plagioclase Ultraphyric Basalt group in the Neogene flood basalt piles of eastern Iceland: Volcanic architecture and mode of emplacement

    Science.gov (United States)

    Oskarsson, B. V.; Riishuus, M. S.

    2013-12-01

    3D photogrammetry in conjunction with ground mapping was applied in order to assess the architecture of a Plagioclase Ultraphyric Basalt (PUB) group in eastern Iceland, namely the Grænavatn group. The ~10 Myr old group is exposed in steep glacially carved fjords and can be traced over 60 km along strike. Two feeder dikes have been found and show that the group erupted along the trend of the dike swarm associated with the Breiddalur central volcano. The group has 9--14 flows where thickest, and thins to about 3--4 flows up-dip to the east within the distance of 15-20 km from the source. We have estimated the volume of the group to exceed 40 km3. The flows have mixed architecture of simple and compound morphology. The flow lobes have thicknesses from 1--24 m and many reach lengths over 1000 m. The surface morphology varies from rubbly to scoriaceous, but is dominantly of pahoehoe style. The internal structure of the lava flows is well preserved and the flows display abundant vesicle cylinders. The modal percentage of An-rich plagioclase macrocrysts varies from 25--50 % and they are in the range of 5--30 mm. The aspect ratio of the group and the nature of the flows indicate fissure-fed eruptions. A thick flow found at the base of the group in various locations seems to record the largest eruption episode in the formation of the group. This phase is also the most abundant in macrocryst. An asymmetric buildup is seen in one location and may have characterized the general buildup of the group. The general morphology of the lava flows suggests low viscous behavior, at odds with the high crystal content. Petrographic observations and mineral chemistry shows that the plagioclase macrocrysts are very calcic (An80-85) and in disequilibrium with the groundmass and plagioclases therein (An50-70). Thus the apparent lava rheology and emplacement of the PUBs was likely achieved due to fast ascent of the magma through the crust and transfer of heat from the primitive macrocrysts

  10. Magma/metal compatibility study: compatibility of metals in molten degassed tholeiitic basalt

    International Nuclear Information System (INIS)

    The compatibility of ten commercially available alloys with molten (13000C) degassed tholeiitic basalt was studied. Results can be explained on the basis of (1) the relative free energies of formation of pertinent oxides and (2) shifts in the chemical equilibrium among iron species. (auth)

  11. Thermal spraying of basalt for abrasion protective coatings using WSP, HVOF and APS

    Czech Academy of Sciences Publication Activity Database

    Berghaus-Oberste, J.; Chráska, Tomáš; Neufuss, Karel; Moreau, Ch.; Chráska, Pavel

    Düsseldorf : DVS-Verlag, Dusseldorf, 2005 - (Lugscheider, E.), s. 1235-1240 ISBN 3-87155-793-5. [International Thermal Spray Conference, ITSC 2005. Basel (CH), 2.5.2005-4.5.2005] Keywords : thermal spraying * basalt * ceramic s * abrasion Subject RIV: JH - Ceramic s, Fire-Resistant Materials and Glass

  12. Geology of hole drill thermal infra basaltic (Guarani Aquifer System) in Salto Uruguay

    International Nuclear Information System (INIS)

    This paper deals with the lithological description of a thermal infrabasaltic (Guarani Aquifer System) hole drill cutting in Dayman (Kanarek Hotel), Salto department (Uruguay). This hole drill shows 152 meters of Buena Vista Formation (Upper Permian- Lower Triassic), 188 meters of Tacuarembo Formation (Upper Jurassic-Lower Cretaceous) and 940meters of Arapey Formation (Lower Cretaceous). Petrographical studies of six basaltic levels were done

  13. Glass and mineral chemistry of northern central Indian ridge basalts: Compositional diversity and petrogenetic significance

    Digital Repository Service at National Institute of Oceanography (India)

    Ray; Banerjee, R.; Iyer, S.D.; Basavalingu, B.; Mukhopadhyay, S.

    seamount shows more fractionated characters (Mg: 0.56-0.57) compared to the outer ridge flank lava of the VT area (Mg: 0.63-0.65). This study concludes that present basalts experienced low-pressure crystallization at a relatively shallow depth...

  14. Basalt Waste Isolation Project. Quarterly report, July 1, 1981-September 30, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Deju, R.A.

    1981-11-01

    This document reports progress made in the Basalt Waste Isolation Project during the fourth quarter of fiscal year 1981. Efforts are described for the following programs of the project work breakdown structure: systems, waste package, site, repository, regulatory and institutional, test facilities, and in-situ test facilities.

  15. Effect of Loading Rate on the Behaviour of Partially Pyrolyzed Basalt Fibre Reinforced Composite

    Czech Academy of Sciences Publication Activity Database

    Halasová, Martina; Chlup, Zdeněk; Černý, Martin; Strachota, Adam; Sucharda, Zbyněk; Dlouhý, Ivo

    Montecatini Terme : CIMTEC, 2014. [CIMTEC 2014. Ceramics Congress /13./. 08.06.2014-13.06.2014, Montecatini Terme] R&D Projects: GA ČR GAP107/12/2445 Institutional support: RVO:68081723 ; RVO:67985891 ; RVO:61389013 Keywords : pyrolysis * basalt fibre * impact loading Subject RIV: JI - Composite Materials

  16. Olivine Major and Trace Element Compositions in Southern Payenia Basalts, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina; Portnyagin, Maxim; Hoernle, Kaj;

    2015-01-01

    Olivine major and trace element compositions from 12 basalts from the southern Payenia volcanic province in Argentina have been analyzed by electron microprobe and laser ablation inductively coupled plasma mass spectrometry. The olivines have high Fe/Mn and low Ca/Fe and many fall at the end of the...

  17. Mossbauer spectroscopy of magnetic minerals in basalt on Earth and Mars

    DEFF Research Database (Denmark)

    Gunnlaugsson, H. P.; Rasmussen, H.; Kristjansson, L.;

    2008-01-01

    Mossbauer spectroscopy of iron-titanium containing spinel phases is reviewed. New techniques are presented for determination of their composition using room-temperature Mossbauer spectroscopy. An example of thermal alteration processes is described. The speciality of olivine-containing basalt is ...

  18. Modeled Top of the Grande Ronde Basalt Geomodel Unit (grtop_f)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The grtop_f grid represents the modeled elevation of the top of the Grande Ronde Basalt geomodel unit at a 500 foot resolution. It is one grid of a geomodel that...

  19. Modeled Top of the Saddle Mountains Basalt Geomodel Unit (smtop_f)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The smtop_f grid represents the modeled elevation of the top of the Saddle Mountains Basalt geomodlel unit at a 500 foot resolution. It is one grid of a geomodel...

  20. Modeled Combined Extent of All Columbia River Basalt Units (CRB_extent4xconnections)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This shapefile was created as a boundary for the Columbia River Basalt extent and a buffered version was used to clip the geomodel unit grids. As part of a U.S....

  1. Modeled Top of the Wanapum Basalt Geomodel Unit (wntop_f)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The wntop_f grid represents the modeled elevation of the top of the Wanapum Basalt geomodel unit at a 500 foot resolution. It is one grid of a geomodel that...

  2. Mineralogy of the mid-ocean-ridge basalt source from neodymium isotopic composition of abyssal peridotites.

    Science.gov (United States)

    Salters, Vincent J M; Dick, Henry J B

    2002-07-01

    Inferring the melting process at mid-ocean ridges, and the physical conditions under which melting takes place, usually relies on the assumption of compositional similarity between all mid-ocean-ridge basalt sources. Models of mantle melting therefore tend to be restricted to those that consider the presence of only one lithology in the mantle, peridotite. Evidence from xenoliths and peridotite massifs show that after peridotite, pyroxenite and eclogite are the most abundant rock types in the mantle. But at mid-ocean ridges, where most of the melting takes place, and in ophiolites, pyroxenite is rarely found. Here we present neodymium isotopic compositions of abyssal peridotites to investigate whether peridotite can indeed be the sole source for mid-ocean-ridge basalts. By comparing the isotopic compositions of basalts and peridotites at two segments of the southwest Indian ridge, we show that a component other than peridotite is required to explain the low end of the (143)Nd/(144)Nd variations of the basalts. This component is likely to have a lower melting temperature than peridotite, such as pyroxenite or eclogite, which could explain why it is not observed at mid-ocean ridges. PMID:12097907

  3. Upper Basalt-Confined Aquifer System in the Southern Hanford Site

    International Nuclear Information System (INIS)

    The 1990 DOE Tiger Team Finding GW/CF-202 found that the hydrogeologic regime at the Hanford Site was inadequately characterized. This finding also identified the need for completing a study of the confined aquifer in the central and southern portions of the Hanford Site. The southern portion of the site is of particular interest because hydraulic-head patterns in the upper basalt-confined aquifer system indicate that groundwater from the Hanford central plateau area, where contaminants have been found in the aquifer, flows southeast toward the southern site boundary. This results in a potential for offsite migration of contaminants through the upper basalt-confined aquifer system. Based on the review presented in this report, available hydrogeologic characterization information for the upper basalt-confined aquifer system in this area is considered adequate to close the action item. Recently drilled offsite wells have provided additional information on the structure of the aquifer system in and near the southern part of the Hanford Site. Information on hydraulic properties, hydrochemistry, hydraulic heads and flow directions for the upper basalt-confined aquifer system has been re-examined and compiled in recent reports including Spane and Raymond (1993), Spane and Vermeul ( 1994), and Spane and Webber (1995)

  4. Paleomagnetism and the compositions of highly-oxidised iron-titanium oxides in basalts

    Science.gov (United States)

    Smith, P.J.

    1968-01-01

    As a preliminary step towards determination of the source of the natural remanence in highly-oxidised basalt lava flows, electron probe microanalysis has been carried out on the two main phases in each of two types of highly-oxidised iron-titanium oxide. The discovery of the source of NRM in these basalts is important because the correlations obtained recently by several workers between high oxidation and reversed polarity in basalts appear to support the possibility of self-reversal, even though some of the rocks studied give independent indications that the reversed magnetizations are due to field reversal. In one type of grain analysed the probe data are consistent with a titanohematite phase and a pseudobrookite phase. This agrees with previous petrographic data. In the other type of grain the probe data are consistent with one phase of titanohematite but contradict petrographic data by showing that the other phase cannot be titanomagnetite. It is concluded that significant contributions to the NRM could possibly arise from the titanohematite (whose magnetic properties in basalts are little known) or the unindentified phase (unless subsequent work rules this phase out), but not in the pseudobrookite phase. However, the NRM may not lie in the analysed grains at all; and other workers are at present investigating this possibility. ?? 1968.

  5. Basalt catalyzed carbonate precipitation reactions using carbon dioxide at low temperatures and low pressures

    Science.gov (United States)

    Petrik-Huff, C.; Finkelstein, D. B.; Mabee, S. B.

    2011-12-01

    Increased attention is being paid to basalts as host formations for the geologic sequestration of anthropogenically produced CO2. Here, we present preliminary results of batch experiments conducted on basalts from the Hartford Basin, the Deerfield and the Holyoke Basalt, to better constrain the optimum conditions to maximize carbon sequestration through the precipitation of carbonate. The purpose of this work is to explore options for CO2 sequestration in a locality where there is a lack of large geologic reservoirs appropriate for storage. In these experiments, 10 grams of 400 micron Deerfield and Holyoke basalt was reacted with deionized water for three hours both at and below supercritical conditions. These experiments showed carbonate precipitation of 15% was consistent at low pressures of CO2 (800 psi) both at high (100 Celsius) and low (20 Celsius) temperatures. These ranges of carbonate precipitation were greatest (15%) when CO2 was at low pressures. Experiments conducted at supercritical conditions precipitated a maximum of 4.7% carbonate. This information is valuable when considering alternative sequestration mechanisms that could be operated adjacent to power generation facilities or more industrial pure sources of CO2. The possibility of low pressure/temperature sequestration reactors to be operated in areas where transport to regional or national sequestration facilities may be cost prohibitive is a parallel course of action that should also be considered. Additionally, it is important to consider how a small ex-situ carbon sequestration project can help increase public acceptance of carbon capture and sequestration.

  6. Disruption of tephra fall deposits caused by lava flows during basaltic eruptions

    Science.gov (United States)

    Brown, R. J.; Thordarson, T.; Self, S.; Blake, S.

    2015-10-01

    Observations in the USA, Iceland and Tenerife, Canary Islands reveal how processes occurring during basaltic eruptions can result in complex physical and stratigraphic relationships between lava and proximal tephra fall deposits around vents. Observations illustrate how basaltic lavas can disrupt, dissect (spatially and temporally) and alter sheet-form fall deposits. Complexity arises through synchronous and alternating effusive and explosive activity that results in intercalated lavas and tephra deposits. Tephra deposits can become disrupted into mounds and ridges by lateral and vertical displacement caused by movement (including inflation) of underlying pāhoehoe lavas and clastogenic lavas. Mounds of tephra can be rafted away over distances of 100 s to 1,000 s m from proximal pyroclastic constructs on top of lava flows. Draping of irregular topography by fall deposits and subsequent partial burial of topographic depressions by later lavas can result in apparent complexity of tephra layers. These processes, deduced from field relationships, have resulted in considerable stratigraphic complexity in the studied proximal regions where fallout was synchronous or alternated with inflation of subjacent lava sheets. These mechanisms may lead to diachronous contact relationships between fall deposits and lava flows. Such complexities may remain cryptic due to textural and geochemical quasi-homogeneity within sequences of interbedded basaltic fall deposits and lavas. The net effect of these processes may be to reduce the usefulness of data collected from proximal fall deposits for reconstructing basaltic eruption dynamics.

  7. Petrological Characteristics and Genesis of the Central Indian Ocean Basin Basalts

    Digital Repository Service at National Institute of Oceanography (India)

    Das, P.; Iyer, S.D.; Hazra, S.

    The Central Indian Ocean Basin (CIOB) basalts are plagioclase-rich, while olivine and pyroxene are very few. The analyses of 41 samples reveal high FeO sup(T) (approx. 10-18 wt percent) and TiO sub(2) (approx. 1.4-2.7 wt percent) indicating a...

  8. INVESTIGATION OF SOFTENING AGENT PREPARATION AND PERFORMANCE OF HANDMADE ECOCOMPOSITES WITH CONIFEROUS WOOD AND BASALT FIBERS

    Institute of Scientific and Technical Information of China (English)

    Guangjian Wang; Deku Shang; Kailiang Zhang; Linna Hu; Zhenhua Guo

    2004-01-01

    In this investigation, basalt mineral fiber softening agent was prepared in order to obtain desirable flexible performance. Stability and physical chemistry natures of softening agent were evaluated by particle size distribution, dilution, storage and folding endurance etc. Constitutes of basalt and wood fibers were determined by energy dispersion analysis X-ray which served as an accessory of scanning electron microscopy (SEM-EDAX). Naturally degradable ecocomposite was prepared by basalt and wood fibers. The results of SEM observation illustrated that the wood and basalt fibers were blended uniformly. The impact factors of beating degree, content of wood fibers and adhesive etc. were discussed. The structure of the naturally degradable ecocomposite was contrasted with that of pure wood fibers and the cause of excellent filtration performance was analyzed. Compared with traditional methods, it was of saving wood resource,a large amount of water and reducing second pollution. As a consequence, the ecocomposite harmonized with environment and accorded with requirement of benignly friendly environment.

  9. Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

    Science.gov (United States)

    Cox, Sarah B.; Lui, Donovan; Gou, Jihua

    2014-01-01

    The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200C, beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

  10. Petrochemistry and tectonic significance of Lower Cretaceous Barros Arana Formation basalts, southernmost Chilean Andes

    Science.gov (United States)

    Stern, C. R.; Mohseni, P. P.; Fuenzalida, P. R.

    The Lower Cretaceous Barros Arana Formation (Albian, hornblende KAr age of 104 Ma), in the Magallanes region of Chile, consists of a sequence of spilitized clinopyroxene- and amphibole-bearing mafic dikes and lavas, and volcaniclastic breccias, occurring within the sedimentary infill of the Rocas Verdes marginal basin and its eastward extension onto the Cretaceous continental platform. Although the original alkali and alkaline earth element concentrations of the basaltic lavas and dikes have been altered by spilitization, the presence of relict pargasitic amphibole phenocrysts, the absence of orthopyroxene, and high LREE contents and LREE/HREE ratios imply mildly alkaline affinities for these basalts. Their low TiO 2 and HFSE (Zr, Nb, Ta, and Hf) contents and high LREE/HFSE ratios suggest affinities with convergent plate boundary arc magmas. The Barros Arana basalts are interpreted as mafic members of the mildly alkaline shoshonitic rock suite of subduction-related arcs. They may have formed as subduction geometry began to undergo the changes (flattening) that ultimately led to the initiation of the closure, deformation, and uplift of the Rocas Verdes basin by the late or post-Albian. The low initial 87Sr/ 86Sr (0.7031) and high initial 143Nd/ 144Nd (0.51277) of the basalts indicate that a generally extensional tectonic regime east of the main calc-alkaline arc allowed eruption of these mafic shoshonites without interaction with continental crust (in contrast to the contemporaneous plutons of the Patagonian batholith).

  11. Influences of chemical aging on the surface morphology and crystallization behavior of basaltic glass fibers

    DEFF Research Database (Denmark)

    Lund, Majbritt Deichgræber; Yue, Yuanzheng

    2008-01-01

    The impact of aging in high humidity and water on the surface morphology and crystallization behavior of basaltic glass fibers has been studied using scanning electron microscopy, transmission electron microscopy, calorimetry and X-ray diffraction. The results show that interaction between the...

  12. Investigating the explosivity of shallow sub-aqueous basaltic eruptions

    Science.gov (United States)

    Murtagh, R.; White, J. D. L.

    2009-04-01

    Volcanic eruptions produce pyroclasts containing vesicles, clearly implying exsolution of volatiles from the magma has occurred. Our aim is to understand the textural characteristics of vesiculated clasts as a quantitative indicator of the eruptive behaviour of a volcano. Assessing water's role in volatile degassing and outgassing has been and is being well documented for terrestrial eruptions; the same cannot be said, however, for their shallow subaqueous counterparts. The eruptive behaviour of Surtseyan volcanoes, which include both subaqueous and subaerial phases (for example, the type-location Surtsey, Iceland in 1963) is under investigation here and for good reason. Volcanic eruptions during which water and basaltic magma come into contact appear to ignite violent eruptions of many of the small "monogenetic" volcanoes so abundant on Earth. A key problem remains that detailed conditions of water-magma interactions are not yet fully understood. Field samples obtained from exposed sequences deposited originally in a subaqueous environment allow for the necessary analysis of lapilli. With the aid of experimental data, mathematical modelling and terrestrial analogues the ambition is to unravel volatile degassing, ascent histories and fragmentation processes, allowing us ultimately to identify both the role water plays in the explosivity of shallow subaqueous eruptions, and the rise history of magma to the point of interaction. The first site, Pahvant Butte is located in southwest Utah, U.S. It is a well preserved tuff cone overlying a subaqueously deposited mound of glassy ash composed of sideromelane and tachylite. It was erupted under ~85m of water into Lake Bonneville approximately 15,300 years ago. Our focus is on samples collected from a well-bedded, broadly scoured coarse ash and lapilli lithofacies on the eastern flank of the edifice. Vesicularity indices span from 52.6% - 60.8%, with very broad vesicularity ranges, 20.6% - 81.0% for one extreme sample. The

  13. Compositional Variations of Primary Basalts in the Poison Lake Chain, Lassen Region of Northern California

    Science.gov (United States)

    Lewis, G. T.; Teasdale, R.; Wenner, J. M.

    2015-12-01

    Multiple compositional mantle domains are represented by primitive basalts of the Poison Lake chain (PLC), located east of the Lassen Volcanic Center in the southern Cascades and on the western margin of the Basin and Range. Four of the nine compositional groups of PLC basalts include primary basalt samples that represent distinct mantle compositions from which other samples are likely derived. Primitive basalts from two of the groups, the old railroad grade (bg; 102.1 +/- 11.4 ka) and the basalts of Poison Butte (bp; 105.0 +/- 6.0 ka), spatially and chronologically overlap. Both groups are primitive basalts that have phenocrysts of olivine, plagioclase and clinopyroxene. However, bg has larger, more euhedral olivine while bp has fewer, smaller, anhedral and embayed olivine phenocrysts. Compositionally, bg has higher whole-rock MgO (9.2-12.2 %) and Ni (189-238 ppm) and lower Zr (57-89 ppm) than bp (MgO = 5.3-7.8 %; Ni = 35-89 ppm; Zr = 98-153 ppm), suggesting bp has undergone more fractionation than bg. MELTS and REE models predict that the most primitive unit of bg (bg3) could have fractionated to produce the other three bg units. Similarly, MELTS and REE models suggest that four of the six units of bp can be derived by fractional crystallization from bg3. However, those models require that bg3 would need to fractionate between 40-50% in order to generate the bp compositions. Unreasonably high % fractionation suggests that the relationship between bg and bp groups is more complex than simple fractionation allows, but their similar Cr spinel compositions (bg Cr# =32.9-50.9 and bp Cr# = 44.0-56.3) suggest bg and bp are likely derived from a common mantle source. Additional petrogenetic modeling and isotope analyses will help clarify the relationship between PLC primitive basalt groups. The combination of small scale mantle heterogeneities along with detailed examination of magma processing are only recognized in the PLC with high density sampling, which may be

  14. Microbiological and Mineralogical Characterization of Columbia River Basalts Prior to Supercritical Carbon Dioxide Addition

    Science.gov (United States)

    Colwell, F. S.; Fisk, M. R.; Yip, H.; Schwartz, A.; Briggs, B. R.; Spane, F.

    2009-12-01

    Deep geologic sequestration of supercritical carbon dioxide can remove excess carbon dioxide from the atmosphere but will cause profound changes to the geochemistry and microorganisms in the deep strata where it is injected. Here we report the original subsurface microbial constituents in basalt aquifers where supercritical carbon dioxide will be injected as part of the DOE Big Sky Regional Partnership field pilot investigation. Microbial cells were acquired by filtration of water from five discrete depth intervals in the Columbia River basalts during drilling of the borehole in eastern Washington state. Microbes were present in all five of the groundwater samples collected. DNA extracted from the cells was successfully amplified using 16S rRNA gene primers for bacteria, but not archaea. Terminal restriction fragment length polymorphism suggested that microbial communities in aquifers from the upper Grand Ronde basalt flows (518 to 553 m) were similar to each other, but distinct from those present in groundwater from the shallower, overlying Wanapum and deeper Grand Ronde basalt flows. Quantitative polymerase chain reaction directed at the 16S rRNA gene indicated that the aquifers had approximately 10,000 cells per ml. To date, our analysis demonstrates the presence of diverse microbial communities at and above the depths where a limited field test carbon dioxide injection (ca. 1,000 metric tons) is planned for early in 2010. A variety of secondary mineral assemblages (mainly clay minerals, silicates and carbonates) have been observed in thin section, and X-ray diffraction examination of the basalt cuttings from the pilot characterization borehole. This pre-injection study supports our inquiry of how indigenous microbial communities may be altered by supercritical carbon dioxide injection, and possible processes that may increase basalt reaction/weathering and re-precipitation of carbonate minerals. Microbial communities that become established after the carbon

  15. Effect of Miocene basaltic volcanism in Shanwang (Shandong Province, China) on environmental changes

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Miocene (16-10 Ma) basalts, together with significantly well-preserved fossils (including animal and plant fossils) in the contemporaneously tephra-rich Maar sediments, are located in Shanwang volcanic region, Shandong Province, China. Distribution area of the basaltic eruption products is about 240 km2. Detailed field observations indicate that most of basaltic rocks are fissure eruptive products and some are central eruptives constrained by linear faults. The well-preserved fossils in the lacustrine deposits have been considered to be a result of mass mortalities. Based on physically volcanologic modeling results, eruption column of the basaltic fissure activities in the Shanwang volcanic region is estimated to have entered the stratosphere. Petrographic observations indicate that the basalts have porphyritic textures with phenocrysts of olivine, pyroxene, plagioclase feldspar and alkali feldspar setting in groundmass of plagioclase feldspar, alkali feldspar, quartz, apatite and glass. Based on observations of tephra, tuff and tuffites collected in the Maar sediments of the Shanwang area, we determined major element oxide concentrations and volatile composition of melt inclusions in phenocrysts and matrix glasses by electron microprobe analysis. Volatile (including S, Cl, F and H2O) concentrations erupted into the stratosphere were estimated by comparing pre- and post-eruptive volatile concentrations. Our determination results show that contents of S, Cl, F and H2O emitted into the stratosphere were 0.18%-0.24%, 0.03%-0.05%, 0.03%-0.05% and 0.4%-0.6%, respectively, which was characterized by high-S contents erupted. Amounts of volatiles emitted in the Shanwang volcanic region are much higher than those in eruptions which had a substantial effect on climate and environment. According to the compositions and amounts of the volatiles erupted from the Miocene basaltic volcanism in Shanwang, we propose a hypothesis that volatile-rich basaltic volcanism could result in

  16. Silicon isotope systematics of acidic weathering of fresh basalts, Kilauea Volcano, Hawai'i

    Science.gov (United States)

    Chemtob, Steven M.; Rossman, George R.; Young, Edward D.; Ziegler, Karen; Moynier, Fréderic; Eiler, John M.; Hurowitz, Joel A.

    2015-11-01

    Silicon stable isotopes are fractionated by a host of low-temperature aqueous processes, making them potentially useful as a weathering proxy. Here we characterize the silicon isotope signature of surficial chemical weathering of glassy basaltic lava flows at Kilauea Volcano, Hawaii. Fresh basalt flow surfaces (silica surface coatings up to 80 μm thick. These silica coatings and associated silica cements are enriched in the heavier isotopes of Si (δ30SiNBS-28 = +0.92‰ to +1.36‰) relative to their basaltic substrate (δ30SiNBS-28 = -0.3‰ to -0.2‰). Secondary clays and opals are typically depleted in 30Si relative to the dissolved reservoirs from which they precipitated, so this sense of isotopic fractionation is unusual. Mechanisms capable of producing isotopically heavy secondary minerals were explored by conducting batch alteration experiments on fresh basaltic glass. Batch acidic alteration of basalt glass in HCl, H2SO4, and HF produced silica-rich surface layers resembling the Hawaiian surface coatings. Differences in fluid chemical composition affected the direction and magnitude of Si isotope fractionation. Basalt leaching in HCl or H2SO4 produced 30Si-enriched fluids (1000 ln αprecip-Si(aq) ≅ -0.8‰) and 30Si-depleted secondary silica layers. In contrast, HF-bearing experiments produced highly 30Si-depleted fluid compositions (1000 ln αprecip-Si(aq) up to +8‰). Larger isotopic fractionations were observed in experiments with lower fluid-rock ratios. In Hawaii, where altering fluids contain H2SO4 and HCl but minimal HF, high δ30Si values for the silica coatings were likely achieved by Rayleigh fractionation. Aqueous 30Si-enriched silica was released during incongruent basalt dissolution then subsequently transported and deposited from an evaporating solution at the flow surface. Our results indicate that (1) altering fluid chemistry and fluid-rock ratio impact the Si isotope signature of chemical weathering and (2) δ30Si of solids produced

  17. Partial crystallization of picritic melt and its applications for the genesis of high-Ti and low-Ti basalts

    Science.gov (United States)

    Yang, J.; WANG, C.; Jin, Z.; Jin, S.; Yan, S.

    2015-12-01

    Geochemical and petrological studies have revealed the existence of high-Ti and low-Ti basalts in large igneous provinces (LIPs). However the originate of these high-Ti and low-Ti magmas are still under debate. Several different mechanisms have been proposed: (1) the high-Ti basalts are formed by the melting of mantle plume containing recycled oceanic crust (Spandler et al., 2008) while low-Ti basalts are formed by the melting of subcontinental lithospheric mantle (Xiao et al., 2004); (2) both high-Ti and low-Ti basalts are from mantle plume source, but the production of high-Ti basalts are associated with the thick lithosphere while the low-Ti basalts are controlled by the thin lithosphere (Arndt et al., 1993); (3) they are derived from the different degrees of melting, with high-Ti basalts representing low degree of partial melting of mantle plume (Xu et al., 2004). The low Mg# (below 0.7) of high-Ti and low-Ti basalts provides that they are far away from direct melting of mantle peridotite. In addition, seismic data indicate unusually high seismic velocities bodies beneath the LIPs which explained by the fractionated cumulates from picritic magmas (Farnetani et al., 1996). Therefore, we believed that the crystallization differentiation process might play a more significant role in the genesis of high-Ti and low-Ti basalts.In order to investigate the generation of high-Ti and low-Ti basalts, a series of high pressure and high temperature partial crystallization experiments were performed at pressures of 1.5, 3.0 and 5.0 GPa and a temperature range of 1200-1700℃. The starting material is picrate glass with relative high TiO2 (2.7 wt %), which is synthesized according to the chemical composition of primary magmas of Emeishan LIP (Xu et al., 2001). The experimental results show that: (1) At a given pressure, the TiO2 content is decreased with increasing melt fraction; (2) At a given melt fraction, the TiO2 content of melts is increased with increasing pressure. On

  18. Petrogenesis of Late Cenozoic basalts from North Hainan Island: Constraints from melt inclusions and their host olivines

    Science.gov (United States)

    Liu, Jian-Qiang; Ren, Zhong-Yuan; Nichols, Alexander R. L.; Song, Mao-Shuang; Qian, Sheng-Ping; Zhang, Yan; Zhao, Pei-Pei

    2015-03-01

    Melt inclusions and their host olivines in basaltic lavas provide important information about the nature of their mantle source. We present the first analyzed chemical data of olivine-hosted melt inclusions in Cenozoic basalts from the North Hainan Island and report the discovery of both tholeiitic and alkalic melt inclusions in a single rock sample. Cenozoic basalts from the Hainan Island are predominantly tholeiites with only small amounts of alkali basalts. There is a much broader compositional variation in melt inclusions than whole rocks. Compared to partial melts of mantle peridotite, the Hainan basalts have lower CaO, Na2O/TiO2, CaO/Al2O3 and Co/Fe, and higher TiO2, FeO∗, Fe/Mn, Zn/Fe and Zn/Mn. The olivine phenocrysts from the Hainan basalts contain lower Ca and Mn, and higher Ni and Fe/Mn than those of olivines crystallized from partial melts of peridotite. Projections from or towards olivine into the plane CS-MS-A for melt inclusions and whole rocks with MgO >7.5 wt% imply that the residual minerals in the source of the tholeiites are mainly clinopyroxene and garnet, possibly with some orthopyroxene, while in the source of the alkali basalts they are dominated by clinopyroxene and garnet. This indicates that a pyroxenite component could serve as the source lithology of the Hainan basalts. The OIB-like trace element compositions, with Ba, Sr, Nb and Ta positive anomalies, and Th and U negative anomalies, of the Hainan basalts suggest that a recycled oceanic crust component was involved in the source of the Hainan basalts. Based on a CMAS projection of primary magma compositions of the whole rocks and melt inclusions, we infer that a stage-2 silica-deficient pyroxenite derived from melt-peridotite reaction or mechanical mixing between recycled oceanic crust and peridotite can serve as the source lithology. Partial melts derived from such a source can match the overall compositions of the Hainan basalts better than those of MORB-eclogite and fertile

  19. Experimental study on the mechanical properties and microstructure of chopped basalt fibre reinforced concrete

    International Nuclear Information System (INIS)

    Highlights: • Effect of volume fraction and length of basalt fibre on concrete properties is tested. • Adding basalt fibre is found to improve mechanical properties of concrete. • A good bond between basalt fibre and matrix interface is observed in the early age by SEM. • MIP analysis shows basalt fibre concrete presents higher porosity. - Abstract: With high ductility and sufficient durability, fibre reinforced concrete (FRC) is widely used. In this study, the effects of the volume fraction and length of basalt fibre (BF) on the mechanical properties of FRC were analyzed. Coupling with the scanning electron microscope (SEM) and mercury intrusion porosimeter (MIP), the microstructure of BF concrete was studied also. The results show that adding BF significantly improves the tensile strength, flexural strength and toughness index, whereas the compressive strength shows no obvious increase. Furthermore, the length of BF presents an influence on the mechanical properties. Compared with the plain concrete, the compressive, splitting tensile and flexural strength of concrete reinforced with 12 mm BF increase by −0.18–4.68%, 14.08–24.34% and 6.30–9.58% respectively. As the BF length increasing to 22 mm, corresponding strengths increase by 0.55–5.72%, 14.96–25.51% and 7.35–10.37%, separately. A good bond between the BF and the matrix interface is observed in the early age. However, this bond shows degradation to a certain extent at 28 days. Moreover, the MIP results indicate that the concrete containing BF presents higher porosity

  20. Biogeochemistry of Methane-Driven Destruction of Trichloroethylene in a Basalt Aquifer

    Science.gov (United States)

    Colwell, F.; Conrad, M.; Paszcynski, A.; Brodie, E.; Delwiche, M.; Radtke, C.; Lee, H.; Paidisetti, R.; Crawford, R.; Bernardini, N.; Johnson, A.; Starr, R.; Swift, D.; Newby, D.; Barnes, J.

    2008-12-01

    We studied the biogeochemical processes responsible for cycling methane and the fortuitous destruction of trichloroethylene (TCE) across spatially distinct locations in a basalt aquifer. This field study was accomplished by examining the attached and unattached microbial communities inherent to the aquifer by using a flow-through in situ reactor (FTISR) and large volumes of aquifer water from which microbial communities were concentrated. After incubation for 238 days, basalt and water were collected from the FTISR and analyzed using proteomics, gene expression, metabolic activity, microbial community structure, and kinetics of TCE degradation. Stable carbon isotopes and PhyloChip gene hybridization analyses were done on groundwater samples. Microbes from the FTSIR co-metabolically degraded approximately 7.5 mg of TCE per liter of groundwater. Proteins from aerobic methanotrophs were detected in the aquifer and on the basalt from the FTISR. Methanotrophic activity in the groundwater and on the FTISR basalt was also confirmed by combined use of enzyme biochemical probes and fluorescent in situ hybridization. Real-time PCR identified ca. 3000 copies of mmoX (a methanotrophic gene) per g of basalt and reverse transcriptase PCR determined that the mmoX subunit was actively transcribed. Stable carbon isotope ratios of dissolved inorganic carbon (DIC) and dissolved methane indicated increased levels of methane oxidation with distance from the source of the TCE (-55 to 28 per mil for methane; >8 to -13 per mil for DIC) corresponding to increased dissolved oxygen concentrations in the aquifer. These geochemistry data are consistent with community composition and activity determinations that identified a gradient of methanogenic to methanotrophic populations along the contaminant plume. Multiple analyses using samples from the FTISR and aquifer water comprehensively demonstrate that both attached and unattached microbial communities are responsible for methane-driven co

  1. Continental flood basalt weathering as a trigger for Neoproterozoic Snowball Earth

    Science.gov (United States)

    Cox, Grant M.; Halverson, Galen P.; Stevenson, Ross K.; Vokaty, Michelle; Poirier, André; Kunzmann, Marcus; Li, Zheng-Xiang; Denyszyn, Steven W.; Strauss, Justin V.; Macdonald, Francis A.

    2016-07-01

    Atmospheric CO2 levels and global climate are regulated on geological timescales by the silicate weathering feedback. However, this thermostat has failed multiple times in Earth's history, most spectacularly during the Cryogenian (c. 720-635 Ma) Snowball Earth episodes. The unique middle Neoproterozoic paleogeography of a rifting, low-latitude, supercontinent likely favored a globally cool climate due to the influence of the silicate weathering feedback and planetary albedo. Under these primed conditions, the emplacement and weathering of extensive continental flood basalt provinces may have provided the final trigger for runaway global glaciation. Weathering of continental flood basalts may have also contributed to the characteristically high carbon isotope ratios (δ13 C) of Neoproterozoic seawater due to their elevated P contents. In order to test these hypotheses, we have compiled new and previously published Neoproterozoic Nd isotope data from mudstones in northern Rodinia (North America, Australia, Svalbard, and South China) and Sr isotope data from carbonate rocks. The Nd isotope data are used to model the mafic detrital input into sedimentary basins in northern Rodinia. The results reveal a dominant contribution from continental flood basalt weathering during the ca. 130 m.y. preceding the onset of Cryogenian glaciation, followed by a precipitous decline afterwards. These data are mirrored by the Sr isotope record, which reflects the importance of chemical weathering of continental flood basalts on solute fluxes to the early-middle Neoproterozoic ocean, including a pulse of unradiogenic Sr input into the oceans just prior to the onset of Cyrogenian glaciation. Hence, our new data support the hypotheses that elevated rates of flood basalt weathering contributed to both the high average δ13 C of seawater in the Neoproterozoic and to the initiation of the first (Sturtian) Snowball Earth.

  2. Petrography and geochemistry of the enriched basaltic shergottite Northwest Africa 2975

    Science.gov (United States)

    He, Qi; Xiao, Long; Balta, J. Brian; Baziotis, Ioannis P.; Hsu, Weibiao; Guan, Yunbin

    2015-11-01

    We present a study of the petrology and geochemistry of basaltic shergottite Northwest Africa 2975 (NWA 2975). NWA 2975 is a medium-grained basalt with subophitic to granular texture. Electron microprobe (EMP) analyses show two distinct pyroxene compositional trends and patchy compositional zoning patterns distinct from those observed in other meteorites such as Shergotty or QUE 94201. As no bulk sample was available to us for whole rock measurements, we characterized the fusion crust and its variability by secondary ion mass spectrometer (SIMS) measurements and laser ablation inductively coupled plasma spectroscopy (LA-ICP-MS) analyses as a best-available proxy for the bulk rock composition. The fusion crust major element composition is comparable to the bulk composition of other enriched basaltic shergottites, placing NWA 2975 within that sample group. The CI-normalized REE (rare earth element) patterns are flat and also parallel to those of other enriched basaltic shergottites. Merrillite is the major REE carrier and has a flat REE pattern with slight depletion of Eu, parallel to REE patterns of merrillites from other basaltic shergottites. The oxidation state of NWA 2975 calculated from Fe-Ti oxide pairs is NNO-1.86, close to the QFM buffer. NWA 2975 represents a sample from the oxidized and enriched shergottite group, and our measurements and constraints on its origin are consistent with the hypothesis of two distinct Martian mantle reservoirs: a reduced, LREE-depleted reservoir and an oxidized, LREE-enriched reservoir. Stishovite, possibly seifertite, and dense SiO2 glass were also identified in the meteorite, allowing us to infer that NWA 2975 experienced a realistic shock pressure of ~30 GPa.

  3. Petrogenesis of the Northwest Africa 4898 high-Al mare basalt

    Science.gov (United States)

    Li, Shaolin; Hsu, Weibiao; Guan, Yunbin; Wang, Linyan; Wang, Ying

    2016-05-01

    Northwest Africa (NWA) 4898 is the only low-Ti, high-Al basaltic lunar meteorite yet recognized. It predominantly consists of pyroxene (53.8 vol%) and plagioclase (38.6 vol%). Pyroxene has a wide range of compositions (En12-62Fs25-62Wo11-36), which display a continuous trend from Mg-rich cores toward Ca-rich mantles and then to Fe-rich rims. Plagioclase has relatively restricted compositions (An87-96Or0-1Ab4-13), and was transformed to maskelynite. The REE zoning of all silicate minerals was not significantly modified by shock metamorphism and weathering. Relatively large (up to 1 mm) olivine phenocrysts have homogenous inner parts with Fo ~74 and sharply decrease to 64 within the thin out rims (~30 μm in width). Four types of inclusions with a variety of textures and modal mineralogy were identified in olivine phenocrysts. The contrasting morphologies of these inclusions and the chemical zoning of olivine phenocrysts suggest NWA 4898 underwent at least two stages of crystallization. The aluminous chromite in NWA 4898 reveals that its high alumina character was inherited from the parental magma, rather than by fractional crystallization. The mineral chemistry and major element compositions of NWA 4898 are different from those of 12038 and Luna 16 basalts, but resemble those of Apollo 14 high-Al basalts. However, the trace element compositions demonstrate that NWA 4898 and Apollo 14 high-Al basalts could not have been derived from the same mantle source. REE compositions of its parental magma indicate that NWA 4898 probably originated from a unique depleted mantle source that has not been sampled yet. Unlike Apollo 14 high-Al basalts, which assimilated KREEPy materials during their formation, NWA 4898 could have formed by closed-system fractional crystallization.

  4. Wellbore cement fracture evolution at the cement–basalt caprock interface during geologic carbon sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hun Bok; Kabilan, Senthil; Carson, James P.; Kuprat, Andrew P.; Um, Wooyong; Martin, Paul F.; Dahl, Michael E.; Kafentzis, Tyler A.; Varga, Tamas; Stephens, Sean A.; Arey, Bruce W.; Carroll, KC; Bonneville, Alain; Fernandez, Carlos A.

    2014-08-01

    Composite Portland cement-basalt caprock cores with fractures, as well as neat Portland cement columns, were prepared to understand the geochemical and geomechanical effects on the integrity of wellbores with defects during geologic carbon sequestration. The samples were reacted with CO2-saturated groundwater at 50 ºC and 10 MPa for 3 months under static conditions, while one cement-basalt core was subjected to mechanical stress at 2.7 MPa before the CO2 reaction. Micro-XRD and SEM-EDS data collected along the cement-basalt interface after 3-month reaction with CO2-saturated groundwater indicate that carbonation of cement matrix was extensive with the precipitation of calcite, aragonite, and vaterite, whereas the alteration of basalt caprock was minor. X-ray microtomography (XMT) provided three-dimensional (3-D) visualization of the opening and interconnection of cement fractures due to mechanical stress. Computational fluid dynamics (CFD) modeling further revealed that this stress led to the increase in fluid flow and hence permeability. After the CO2-reaction, XMT images displayed that calcium carbonate precipitation occurred extensively within the fractures in the cement matrix, but only partially along the fracture located at the cement-basalt interface. The 3-D visualization and CFD modeling also showed that the precipitation of calcium carbonate within the cement fractures after the CO2-reaction resulted in the disconnection of cement fractures and permeability decrease. The permeability calculated based on CFD modeling was in agreement with the experimentally determined permeability. This study demonstrates that XMT imaging coupled with CFD modeling represent a powerful tool to visualize and quantify fracture evolution and permeability change in geologic materials and to predict their behavior during geologic carbon sequestration or hydraulic fracturing for shale gas production and enhanced geothermal systems.

  5. Petrophysical and geochemical properties of Columbia River flood basalt: Implications for carbon sequestration

    Science.gov (United States)

    Zakharova, Natalia V.; Goldberg, David S.; Sullivan, E. Charlotte; Herron, Michael M.; Grau, James A.

    2012-11-01

    This study presents borehole geophysical data and sidewall core chemistry from the Wallula Pilot Sequestration Project in the Columbia River flood basalt. The wireline logging data were reprocessed, core-calibrated and interpreted in the framework of reservoir and seal characterization for carbon dioxide storage. Particular attention is paid to the capabilities and limitations of borehole spectroscopy for chemical characterization of basalt. Neutron capture spectroscopy logging is shown to provide accurate concentrations for up to 8 major and minor elements but has limited sensitivity to natural alteration in fresh-water basaltic reservoirs. The Wallula borehole intersected 26 flows from 7 members of the Grande Ronde formation. The logging data demonstrate a cyclic pattern of sequential basalt flows with alternating porous flow tops (potential reservoirs) and massive flow interiors (potential caprock). The log-derived apparent porosity is extremely high in the flow tops (20-45%), and considerably overestimates effective porosity obtained from hydraulic testing. The flow interiors are characterized by low apparent porosity (0-8%) but appear pervasively fractured in borehole images. Electrical resistivity images show diverse volcanic textures and provide an excellent tool for fracture analysis, but neither fracture density nor log-derived porosity uniquely correlate with hydraulic properties of the Grande Ronde formation. While porous flow tops in these deep flood basalts may offer reservoirs with high mineralization rates, long leakage migration paths, and thick sections of caprock for CO2 storage, a more extensive multiwell characterization would be necessary to assess lateral variations and establish sequestration capacity in this reservoir.

  6. Petrophysical and Geochemical Properties of Columbia River Flood Basalt: Implications for Carbon Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Zakharova, Natalia V.; Goldberg, David S.; Sullivan, E. C.; Herron, Michael M.; Grau, Jim A.

    2012-11-02

    Abstract This study presents borehole geophysical data and sidewall core chemistry from the Wallula Pilot Sequestration Project in the Columbia River flood basalt. The wireline logging data were reprocessed, core-calibrated and interpreted in the framework of reservoir and seal characterization for carbon dioxide storage. Particular attention is paid to the capabilities and limitations of borehole spectroscopy for chemical characterization of basalt. Neutron capture spectroscopy logging is shown to provide accurate concentrations for up to 8 major and minor elements but has limited sensitivity to natural alteration in fresh-water basaltic reservoirs. The Wallula borehole intersected 26 flows from 7 members of the Grande Ronde formation. The logging data demonstrate a cyclic pattern of sequential basalt flows with alternating porous flow tops (potential reservoirs) and massive flow interiors (potential caprock). The log-derived apparent porosity is extremely high in the flow tops (20%-45%), and considerably overestimates effective porosity obtained from hydraulic testing. The flow interiors are characterized by low apparent porosity (0-8%) but appear pervasively fractured in borehole images. Electrical resistivity images show diverse volcanic textures and provide an excellent tool for fracture analysis, but neither fracture density nor log-derived porosity uniquely correlate with hydraulic properties of the Grande Ronde formation. While porous flow tops in these deep flood basalts may offer reservoirs with high mineralization rates, long leakage migration paths, and thick sections of caprock for CO2 storage, a more extensive multi- well characterization would be necessary to assess lateral variations and establish sequestration capacity in this reservoir.

  7. Petrophysical properties of the Deccan basalts exposed in the Western Ghats escarpment around Mahabaleshwar and Koyna, India

    Science.gov (United States)

    Prasanna Lakshmi, K. J.; Senthil Kumar, P.; Vijayakumar, K.; Ravinder, S.; Seshunarayana, T.; Sen, Mrinal K.

    2014-04-01

    We present petrophysical properties (density, P and S wave velocity, porosity and Poisson's ratio) of the Deccan basalts from the Western Ghats escarpment around Mahabaleshwar and Koyna and characterize the Dhawar basement rocks around Goa. The petrophysical properties of basaltic lava flows show significant variation in the Bushe, Poladpur, Ambenali and Mahabaleshwar Formations that are widespread in the Deccan volcanic province. The Bushe Formation stands out distinctly from other formations because of its lower density, and P and S wave velocity. The porosity (vesicles and amygdales) plays a major role in controlling the variation of the petrophysical properties of the basalts. The Poisson's ratio of the Deccan basalts is largely affected by the vesicular porosity, aspect ratio of the amygdales, and zeolite content. The Dharwar basement rocks (greywackes and granites) are found to be lower in density, P and S wave velocity, and Poisson's ratio than the basaltic rocks. The variation of the petrophysical properties with elevation in the Western Ghats sections roughly follows the geochemical stratigraphy. High porosity of the Bushe and Mahabaleshwar Formations constitute a multi-layered aquifer system in the Deccan volcanic province. In the Koyna earthquake zone, these formations may provide an effective groundwater connectivity between the reservoir and earthquake focal areas. The new petrophysical data of the Deccan basalts and Dharwar basement rocks will help to refine the geophysical models of the southwestern Deccan basalt province.

  8. The influence of hybridization on impact damage behavior and residual compression strength of intraply basalt/nylon hybrid composites

    International Nuclear Information System (INIS)

    Highlights: ► The impact performances of basalt/nylon intraply hybrid composites were studied. ► In basalt/nylon composite, the excellent impact resistance of nylon fiber was used. ► At high impact energy, the hybrid composite have a better property than the pure ones. ► The impact property of hybrid samples is significantly affected by the fiber content. ► SEM analyses show that hybridization can prevent of catastrophic and complete failure. -- Abstract: Low-velocity impact and compression after impact (CAI) tests were performed to investigate the impact behavior of hybrid composite laminates reinforced by basalt-nylon intraply fabrics. The purpose of using this hybrid composite is to combine the good mechanical property of basalt fiber as a brittle fiber with the excellent impact resistance of nylon fiber as a ductile fiber. Five different types of woven fabric with different contents of nylon (0%, 25%, 33.3%, 50% and 100%) were used as reinforcement. The effect of nylon/basalt fiber content on impact parameters, impact damage behavior and CAI strength was studied at different nominal impact energy levels (16, 30 and 40 J). The results indicate that at low impact energy, hybridization and variation in basalt/nylon fiber content cannot improve the impact performance of composite plates. With increasing impact energy, the impact performance becomes more and more dependent on the content of nylon and basalt.

  9. Mapping and compositional analysis of mare basalts in the Aristarchus region of the Moon using Clementine data

    International Nuclear Information System (INIS)

    The process of accurately defining and outlining mare basalt units is necessary for constraining the stratigraphy and ages of basalt units, which are used to determine the duration and the flux of lunar volcanism. We use a combination of Clementine's five-band ultraviolet/visible data and TiO2 and FeO abundance distribution maps to define homogenous mare basalt units and characterize their compositional variations (with maturity) in the Aristarchus region. With 20 groups of distinct mare basaltic soils identified using the method in this paper, six additional spectrally defined areas and five basaltic units are constructed, and their mineralogic quantization values provide new constraints on their temporal and spatial evolution. Our results indicate that the Aristarchus region has diverse basalt units and a complex history of volcanic evolution. We also demonstrate that the techniques, from which spectrally distinct mare basalts can be mapped, performed well in this study and can be confidently expanded to other mare regions of the Moon. (research papers)

  10. Geochemistry and U-Pb zircon ages of plutonic rocks from the Algodões granite-greenstone terrane, Troia Massif, northern Borborema Province, Brazil: Implications for Paleoproterozoic subduction-accretion processes

    Science.gov (United States)

    Costa, Felipe Grandjean da; Palheta, Edney Smith de Moraes; Rodrigues, Joseneusa Brilhante; Gomes, Iaponira Paiva; Vasconcelos, Antonio Maurilio

    2015-04-01

    The Algodões metavolcano-sedimentary sequence is located at the northern margin of the Archean/Paleoproterozoic Troia Massif, northern Borborema Province (NE Brazil). It represents a well-preserved Paleoproterozoic greenstone-like sequence affected by two major plutonic events. The early plutonism, represented by the Cipó orthogneisses, mainly comprises biotite-bearing metatonalites, which share similar geochemical signatures with Archean tonalite-trondjhemite-granodiorite (TTG). For these rocks, we report U-Pb (LA-ICPMS) zircon ages of 2189 ± 14 Ma and 2180 ± 15 Ma. A subsequent plutonic magmatism occurred at ˜2150-2130 Ma and is mainly represented by hornblende-bearing dioritic to tonalitic orthogneisses of the Madalena Suite and São José da Macaoca Complex. Geochemical data indicate that these dioritic/tonalitic orthogneisses have adakitic characteristics and strongly suggest mantle-related magmas. A (sensu stricto) granite plutonism (Serra da Palha orthogneisses) also intruded the Algodões sequence and yielded U-Pb (LA-ICPMS) zircon age of 2150 ± 16 Ma. These granitic orthogneisses show high-K content, A-type characteristics and probably derived from partial melting of a crustal (tonalitic) source. We suggest that the early ˜2190-2160 Ma TTG plutons probably developed in intra-oceanic arc setting, whereas the following ˜2150-2130 Ma adakitic plutons and A-type granitic magmatism developed in response to arc-continent collision.

  11. Dissolution-precipitation reactions and permeability evolution from reactions of CO2-rich aqueous solutions with fractured basalt

    Science.gov (United States)

    Wells, R. K.; Xiong, W.; Bae, Y.; Sesti, E.; Skemer, P. A.; Giammar, D.; Conradi, M.; Ellis, B. R.; Hayes, S. E.

    2015-12-01

    The injection of CO2 into fractured basalts is one of several possible solutions to mitigate global climate change; however, research on carbonation in natural basalts in relation to carbon sequestration is limited, which impedes our understanding of the processes that may influence the viability of this strategy. We are conducting bench-scale experiments to characterize the mineral dissolution and precipitation and the evolution of permeability in synthetic and natural basalts exposed to CO2-rich fluids. Analytical methods include optical and electron microscopy, electron microprobe, Raman spectroscopy, nuclear magnetic resonance (NMR), and micro X-ray computed tomography (μCT) with variable flow rates. Reactive rock and mineral samples consist of 1) packed powders of olivine or natural basalt, and 2) sintered cores of olivine or a synthetic basalt mixture. Each sample was reacted in a batch reactor at 100 °C, and 100 bars CO2. Magnesite is detected within one day in olivine packed beds, and within 15 days in olivine sintered cores. Forsterite and synthetic basalt sinters were also reacted in an NMR apparatus at 102 °C and 65 bars CO2. Carbonate signatures are observed within 72 days of reaction. Longer reaction times are needed for carbonate precipitation in natural basalt samples. Cores from the Columbia River flood basalt flows that contain Mg-rich olivine and a serpentinized basalt from Colorado were cut lengthwise, the interface mechanically roughened or milled, and edges sealed with epoxy to simulate a fractured interface. The cores were reacted in a batch reactor at 50-150 °C and 100 bars CO2. At lower temperatures, calcite precipitation is rare within the fracture after 4 weeks. At higher temperatures, numerous calcite and aragonite crystals are observed within 1 mm of the fracture entrance along the roughened fracture surface. In flow-through experiments, permeability decreased along the fracture paths within a few hours to several days of flow.

  12. Sm-Nd and Rb-Sr Isotopic Studies of Meteorite Kalahari 009: An Old VLT Mare Basalt

    Science.gov (United States)

    Shih, C.-Y.; Nyquist, L. E.; Reese, Y.; Bischoff, A.

    2008-01-01

    Lunar meteorite Kalahari 009 is a fragmental basaltic breccia contain ing various very-low-Ti (VLT) mare basalt clasts embedded in a fine-g rained matrix of similar composition. This meteorite and lunar meteorite Kalahari 008, an anorthositic breccia, were suggested to be paired mainly due to the presence of similar fayalitic olivines in fragment s found in both meteorites. Thus, Kalahari 009 probably represents a VLT basalt that came from a locality near a mare-highland boundary r egion of the Moon, as compared to the typical VLT mare basalt samples collected at Mare Crisium during the Luna-24 mission. The concordant Sm-Nd and Ar-Ar ages of such a VLT basalt (24170) suggest that the extrusion of VLT basalts at Mare Crisium occurred 3.30 +/- 0.05 Ga ag o. Previous age results for Kalahari 009 range from approximately 4.2 Ga by its Lu-Hf isochron age to 1.70?0.04 Ga of its Ar-Ar plateau ag e. However, recent in-situ U-Pb dating of phosphates in Kalahari 009 defined an old crystallization age of 4.35+/- 0.15 Ga. The authors su ggested that Kalahari 009 represents a cryptomaria basalt. In this r eport, we present Sm-Nd and Rb-Sr isotopic results for Kalahari 009, discuss the relationship of its age and isotopic characteristics to t hose of other L-24 VLT mare basalts and other probable cryptomaria ba salts represented by Apollo 14 aluminous mare basalts, and discuss it s petrogenesis.

  13. MARIUS HILLS REGION, MOON: Stratigraphy of low shields and mare basalts

    Science.gov (United States)

    Gebhart, Jennifer; Hiesinger, Harry; van der Bogert, Carolyn; Hendrik Pasckert, Jan; Weinauer, Julia; Lawrence, Samuel; Stopar, Julie; Robinson, Mark

    2016-04-01

    The Marius Hills region consists of more than 250 individual basaltic low shields (usually referred to as "domes") and cones, located on a broad topographic rise. The bases of numerous low shields have slope angles of ~2-3° whereas the upper portions have slopes of ~6-7° [1], interpreted to reflect changes in composition over time [1]. However, the absence of spectral differences between the two dome morphologies and the surrounding mare basalts suggests that the observed morphologies are more plausibly explained by changes in effusion rates, temperature (viscosity), and/or crystallization over time [e.g., 2]. Previous studies indicate that volcanism in this region occurred in the Upper Imbrian (3.2-3.8 Ga) [3], although several other authors reported ages ranging from the Imbrian (~3.3 Ga) to the Eratosthenian (~2.5 Ga) [e.g., 1,2,4]. [2,5] reported that all low shields are embayed by younger mare units, indicating that they formed during an older stage of volcanic activity. Mare basalts surrounding the Marius Hills exhibit absolute model ages of 1.2-3.7 Ga [6]. We used 36 LRO NAC images to perform crater size-frequency distribution (CSFD) measurements. The images were calibrated and map-projected with ISIS 3 and imported into ArcGIS. Within ArcGIS, we used CraterTools [7] to perform our CSFD measurements. The crater size-frequency distributions were then plotted with CraterStats [8], using the production and chronology functions of [9]. We conducted CSFD measurements for 50 Marius Hills low shields. Our count area sizes ranged from 1.06 x 101 to 8.75 x 101 km2; those for adjacent basalts varied between 6.17 x 100 and 8.01 x 101 km2. We determined absolute model ages (AMAs) of 1.03 to 3.65 Ga for the low shields and did not find a spatial correlation of ages versus their locations. CSFD measurements for 27 adjacent basalts show AMAs of 1.20-3.69 Ga. Of those basalts, 24 exhibit AMAs of 3-3.5 Ga; there is no correlation of AMAs and the geographic position of the

  14. Geochemistry and petrogenesis of basaltic rocks from north Queensland: has subduction-modified mantle played a role?

    International Nuclear Information System (INIS)

    Sixty-one basalt samples from North Queensland were analysed for major and 40 for trace elements. Three distinct mantle sources can be inferred from the Sr-Nd-Pb isotope data. One is represented by the early Tertiary Mingela basalts. It has both isotope and element signatures likely derived from an OIB-type sublithospheric mantle source, possibly resulting from interaction of an enriched deep mantle with the overlying depleted asthenosphere of the Pacific-MORB type. A similar-source has been considered as one of the dominant mantle reservoirs for some basalts in NSW and Victoria

  15. Near field chemical speciation: the reaction of uranium and thorium with Hanford basalt and elevated pH

    International Nuclear Information System (INIS)

    The hydrolysis of radionuclides such as thorium and uranium and their subsequent chemisorption on Hanford basalt have been studied using a variety of techniques, including x-ray photoelectron and infrared spectroscopy. Data obtained to date indicate mixed complexes of uranium and thorium to be on the basalt surface, the complexes being radionuclide oxides, hydrated oxides (hydroxides), and carbonates. These findings are discussed with respect to their importance for input for models describing speciation and dissolution processes involving nuclear waste repository materials such as Hanford basalt. 5 figures, 2 tables

  16. Preliminary geochemical and physical testing of materials for plugging of man-made accesses to a repository in basalt

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, C.L.; Anttonen, G.J.; O' Rourke, J.E.; Allirot, D.

    1980-04-01

    The available data on environmental conditions (both natural and man-made) at the Hanford Site are sufficient for preconceptual plug system design. Results of the geochemical testing program indicate that preferred candidate plug materials are chemically nonreactive during laboratory tests that simulated some of the expected environmental conditions. Agitated, crushed-basalt samples and mixtures containing basalt were found to be self-cementing under the hydrothermal conditions. Materials considered most suitable for consideration in future test programs and preconceptual plug design are mixtures of natural materials (basalt, clay, glaciofluvial sand, gravel, and zeolite) and processed natural materials (portland cement Type V and grouts plus additives).

  17. Preliminary geochemical and physical testing of materials for plugging of man-made accesses to a repository in basalt

    International Nuclear Information System (INIS)

    The available data on environmental conditions (both natural and man-made) at the Hanford Site are sufficient for preconceptual plug system design. Results of the geochemical testing program indicate that preferred candidate plug materials are chemically nonreactive during laboratory tests that simulated some of the expected environmental conditions. Agitated, crushed-basalt samples and mixtures containing basalt were found to be self-cementing under the hydrothermal conditions. Materials considered most suitable for consideration in future test programs and preconceptual plug design are mixtures of natural materials (basalt, clay, glaciofluvial sand, gravel, and zeolite) and processed natural materials

  18. Controls on melting at spreading ridges from correlated abyssal peridotite - mid-ocean ridge basalt compositions

    Science.gov (United States)

    Regelous, Marcel; Weinzierl, Christoph G.; Haase, Karsten M.

    2016-09-01

    Variations in the volume and major element composition of basalt erupted along the global mid-ocean ridge system have been attributed to differences in mantle potential temperature, mantle composition, or plate spreading rate and lithosphere thickness. Abyssal peridotites, the residues of mantle melting beneath mid-ocean ridges, provide additional information on the melting process, which could be used to test these hypotheses. We compiled a global database of abyssal peridotite compositions averaged over the same ridge segments defined by Gale et al. (2013). In addition, we calculated the distance of each ridge segment to the nearest hotspots. We show that Cr# in spinel in abyssal peridotites is negatively correlated with Na90 in basalts from the same ridge segments on a global scale. Ridge segments that erupt basalts apparently produced by larger degrees of mantle melting are thus underlain by peridotites from which large amounts of melt have been extracted. We find that near-ridge hotspots have a more widespread influence on mid-ocean ridge basalt (MORB) composition and ridge depth than previously thought. However, when these hotspot-influenced ridge segments are excluded, the remaining segments show clear relationships between MORB composition, peridotite composition, and ridge depth with spreading rate. Very slow-spreading ridges (<20 mm/yr) are deeper, erupt basalts with higher Na90, Al90, K90/Ti90, and lower Fe90, Ca90/Al90, and expose peridotites with lower Cr# than intermediate and fast-spreading ridges. We show that away from hotspots, the spreading-rate dependence of the maximum degree of mantle melting inferred from Cr# in peridotites (FM) and the bulk degree of melting inferred from Na90 in basalts (FB) from the same ridge segments is unlikely to be due to variations in mantle composition. Nor can the effects of dynamic mantle upwelling or incomplete melt extraction at low spreading rates satisfactorily explain the observed compositions of abyssal

  19. Reactive transport modeling of CO2 mineral sequestration in basaltic rocks

    Science.gov (United States)

    Aradottir, E. S.; Sonnenthal, E. L.; Bjornsson, G.; Jonsson, H.

    2011-12-01

    CO2 mineral sequestration in basalt may provide a long lasting, thermodynamically stable, and environmentally benign solution to reduce greenhouse gases in the atmosphere. Multi-dimensional, field scale, reactive transport models of this process have been developed with a focus on the CarbFix pilot CO2 injection in Iceland. An extensive natural analog literature review was conducted in order to identify the primary and secondary minerals associated with water-basalt interaction at low and elevated CO2 conditions. Based on these findings, an internally consistent thermodynamic database describing the mineral reactions of interest was developed and validated. Hydrological properties of field scale mass transport models were properly defined by calibration to field data using iTOUGH2. Reactive chemistry was coupled to the models and TOUGHREACT used for running predictive simulations carried out with the objective of optimizing long-term management of injection sites, to quantify the amount of CO2 that can be mineralized, and to identify secondary minerals that compete with carbonates for cations leached from the primary rock. Calibration of field data from the CarbFix reservoir resulted in a horizontal permeability for lava flows of 300 mD and a vertical permeability of 1700 mD. Active matrix porosity was estimated to be 8.5%. The CarbFix numerical models were a valuable engineering tool for designing optimal injection and production schemes aimed at increasing groundwater flow. Reactive transport simulations confirm dissolution of primary basaltic minerals as well as carbonate formation, and thus indicate in situ CO2 mineral sequestration in basalts to be a viable option. Furthermore, the simulations imply that clay minerals are most likely to compete with magnesite-siderite solid solutions for Mg and Fe leached from primary minerals, whereas zeolites compete with calcite for dissolved Ca. In the case of the CarbFix pilot injection, which involves a continuous

  20. Chemical characterization, nano-particle mineralogy and particle size distribution of basalt dust wastes.

    Science.gov (United States)

    Dalmora, Adilson C; Ramos, Claudete G; Oliveira, Marcos L S; Teixeira, Elba C; Kautzmann, Rubens M; Taffarel, Silvio R; de Brum, Irineu A S; Silva, Luis F O

    2016-01-01

    Understanding the geochemistry of basalt alteration is central to the study of agriculture systems. Various nano-minerals play an important role in the mobilization of contaminants and their subsequent uptake by plants. We present a new analytical experimental approach in combination with an integrated analytical protocol designed to study basalt alteration processes. Recently, throughout the world, ultra-fine and nano-particles derived from basalt dust wastes (BDW) during "stonemeal" soil fertilizer application have been of great concern for their possible adverse effects on human health and environmental pollution. Samples of BDW utilized were obtained from companies in the Nova Prata mining district in southern Brazil for chemical characterization and nano-mineralogy investigation, using an integrated application of advanced characterization techniques such as X-ray diffraction (XRD), High Resolution-Transmission Electron microscopy (HR-TEM)/Energy Dispersive Spectroscopy (EDS)/(selected-area diffraction pattern) SAED, Field Emission-Scanning Electron Microscopy (FE-SEM/EDS), and granulometric distribution analysis. The investigation has revealed that BDW materials are dominated by SiO2, Al2O3, and Fe2O3, with a complex micromineralogy including alkali feldspar, augite, barite, labradorite, hematite, heulandrite, gypsum, kaolinite, quartz, and smectite. In addition, we have identified a number of trace metals such as Cd, Cu, Cr, and Zn, that are preferentially concentrated into the finer, inhalable, dust fraction and, thus, could present a health hazard in the urban areas around the basalt mining zone. The implication of this observation is that use of these nanometric-sized particulates as soil fertilizer may present different health challenges to those of conventional fertilizers, inviting future work regarding the relative toxicities of these materials. Our investigation on the particle size distribution, nano-particle mineralogy and chemical composition in

  1. Use and modification of the Universal Distinct Element Code (UDEC) for basalt block test analysis

    International Nuclear Information System (INIS)

    This report represents the final phase of the ongoing analysis program which sought to use discrete element numerical modeling methods to assess the basic deformational mechanisms of closely jointed basalt based on the results from the Near-Surface Test Facility (NSTF) Block Test. The current work involved the development and use of a three-dimensional version of the Universal Distinct Element Code (UDEC) to verify the results inferred from the previous two-dimensional modeling effort. Generally, the results of this work were in agreement with and thus did verify the previous analyses. The characterization of the basalt deformational mechanisms provided by this program will enable results from the Block Test and other small-scale tests to be extrapolated to the overall rock mass behavior to support repository design activities. 90 figs., 12 tabs

  2. Bimodal magmatism, basaltic volcanic styles, tectonics, and geomorphic processes of the eastern Snake River Plain, Idaho

    Science.gov (United States)

    Hughes, S.S.; Smith, R.P.; Hackett, W.R.; McCurry, M.; Anderson, S.R.; Ferdock, G.C.

    1997-01-01

    Geology presented in this field guide covers a wide spectrum of internal and surficial processes of the eastern Snake River Plain, one of the largest components of the combined late Cenozoic igneous provinces of the western United States. Focus is on widespread Quaternary basaltic plains volcanism that produced coalescent shields and complex eruptive centers that yielded compositionally evolved magmas. The guide is constructed in several parts beginning with discussion sections that provide an overview of the geology followed by road directions, with explanations, for specific locations. The geology overview briefly summarizes the collective knowledge gained, and petrologic implications made, over the past few decades. The field guide covers plains volcanism, lava flow emplacement, basaltic shield growth, phreatomagmatic eruptions, and complex and evolved eruptive centers. Locations and explanations are also provided for the hydrogeology, groundwater contamination, and environmental issues such as range fires and cataclysmic floods associated with the region.

  3. Inverse modeling for field-scale hydrologic and transport parameters of fractured basalt

    International Nuclear Information System (INIS)

    A large-scale test of infiltration into a thick sequence Of fractured Snake River Plain basalts was performed during the summer of 1994 on the Idaho National Engineering Laboratory. Monitoring of moisture and tracer movement during this test provided a set of quantitative measurements from which to obtain a field-scale hydrologic description of the fractured basalts. An inverse modeling study using these quantitative measurements was performed to obtain the representative hydrologic description. This report describes the results of the inverse modeling study and includes the background and motivation for conducting the infiltration test; a brief overview of the infiltration test; descriptions of the calibration targets chosen for the simulation study, the simulation model, and the model implementation; and the simulation results with comparisons to hydrologic and tracer breakthrough data obtained from the infiltration test

  4. Intermediate-scale sodium-concrete reaction tests with basalt and limestone concrete

    International Nuclear Information System (INIS)

    Ten tests were performed to investigate the chemical reactions and rate and extent of attack between sodium and basalt and limestone concretes. Test temperatures ranged from 510 to 8700C (950 to 16000F) and test times from 2 to 24 hours. Sodium hydroxide was added to some of the tests to assess the impact of a sodium hydroxide-aided reaction on the overall penetration characteristics. Data suggest that the sodium penetration of concrete surfaces is limited. Penetration of basalt concrete in the presence of sodium hydroxide is shown to be less severe than attack by the metallic sodium alone. Presence of sodium hydroxide changes the characteristics of sodium penetration of limestone concrete, but no major differences in bulk penetration were observed as compared to penetration by metallic sodium

  5. Geochemistry of Ua Huka basalts (Marquesas): partial melting variations and mantle source heterogeneity

    International Nuclear Information System (INIS)

    The main shield volcano of Ua Huka Island (Marquesas Archipelago) was emplaced between 2.2 and 2.4 Ma, and then affected by two caldera collapse events. After a 0.9 Ma-long gap, volcanic activity resumed with the emplacement of two smaller volcanoes in the southwest part of the island, between 1.5 and 0.75 Ma. The geochemical characteristics of Ua Huka mafic lavas, which range from olivine tholeiites to alkali basalts and basanites, are consistent with a temporal decrease in partial melting degrees of a heterogeneous mantle source. The associated temporal variation of the isotopic signatures of Ua Huka basalts implies a more important contribution of a Depleted MORB Mantle (DMM) end-member during the genesis of the youngest basanitic lavas. Such a variation was not previously documented in the Marquesas Archipelago. (authors)

  6. Scenarios constructed for basaltic igneous activity at Yucca Mountain and vicinity

    International Nuclear Information System (INIS)

    Basaltic volcanism has been identified as a possible future event initiating a release of radionuclides from a potential repository at the proposed Yucca Mountain high-level waste repository site. The performance assessment method set forth in the Site Characterization Plan (DOE, 1988) requires that a set of scenarios encompassing all significant radionuclide release paths to the accessible environment be described. This report attempts to catalogue the details of the interactions between the features and processes produced by basaltic volcanism in the presence of the presumed groundwater flow system and a repository structure, the engineered barrier system (EBS), and waste. This catalogue is developed in the form of scenarios. We define a scenario as a well-posed problem, starting from an initiating event or process and proceeding through a logically connected and physically possible combination or sequence of features, events, and processes (FEPs) to the release of contaminants

  7. Petrogenesis of lunar basalts and the internal constitution and origin of the moon.

    Science.gov (United States)

    Ringwood, A E; Essene, E

    1970-01-30

    Petrographic and electron-microprobe studies combined with high pressure-temperature investigations of phase relationships in average Apollo 11 basalt and possible source material show that the lower parts of maria may be composed of eclogite (density 3.74 grams per cubic centimeter), thus explaining the existence of mascons. The Apollo 11 basalt was probably formed at depths of 200 to 400 kilometers by a small degree of partial melting from pyroxenitic source material [FeO/(FeO + MgO) = 0.25, A1(2)O(3) 4 percent, CaO 3 percent]. This composition may be representative of the lunar interior and yields the observed mean lunar density and moment of inertia. Present data are in conflict with fission, binary planet, and capture hypotheses of lunar origin but are consistent with Ringwood's (1966) precipitation hypothesis. PMID:17781514

  8. The Basalt Waste Isolation Project technical program evaluation process: A criteria-based method

    International Nuclear Information System (INIS)

    The need to objectively evaluate the progress being made by the Basalt Waste Isolation Project (BWIP) toward establishing the feasibility of siting a nuclear waste repository in basalt (NWRB) mandates a process for evaluating the technical work of the project. To assist BWIP management in the evaluation process, the Systems Department staff has developed a BWIP Technical Program Evaluation Process (TPEP). The basic process relates progress on project technical work to the BWIP Functional and System Performance Criteria as defined in National Waste Terminal Storage (NWTS) Criteria Documents. The benefits of the TPEP to BWIP and future plans for TPEP are discussed. During fiscal year (FY) 1982, TPEP will be further formalized and further applied to the review of BWIP technical activities

  9. Age and origin of Southern Patagonian flood basalts, Chile Chico region (46°45'S)

    OpenAIRE

    Petford, N.; Cheadle, M.; Barreiro, B.

    1996-01-01

    De nouvelle données chimiques et radiométriques de la région de Chile Chico, à l'intérieur de l'actuelle lacune de volcanisme, sont présentées pour une coupe détaillée à travers une séquence inférieure de basaltes des plateaux constitués de tholéites à olivine et hyperstène normatif. Des âges 40Ar/39Ar de 51,7 plus ou moins 0,7 à 51,8 plus ou moins 0,9 impliquent une période d'éruption d'environ 0,1 Ma et confirment la similarité d'âge de ces roches avec les basaltes voisins d'Argentine. Les ...

  10. Effect of Crystallisation Degree on Hardness of Basaltic Glass-Ceramics

    DEFF Research Database (Denmark)

    Jensen, Martin; Smedskjær, Morten Mattrup; Yue, Yuanzheng

    The dependence of hardness of basaltic glass-ceramics on their crystallisation degree has been explored by means of differential scanning calorimetry, optical microscopy, X-ray diffraction, and Vickers indentation. Different degrees of crystallisation in the basaltic glasses have been obtained by...... the augite crystals is in the range of the hardness of a similar pyroxene, i.e., a pure diopside crystal. The hardness of diopside has been both measured and calculated. The calculation has been done by considering the strength of each individual bond and the amount of bonds per volume, i.e., by using...... first principle calculations. It is found that the hardness of the glass phase decreases slightly with an increase in the degree of crystallisation, while that of the augite phase drastically decreases....

  11. Low-Ti basalts from the Faroe Islands constrain the early Iceland depleted plume component

    DEFF Research Database (Denmark)

    Søager, Nina; Holm, Paul Martin

    be an early version of the ID1 component but it could also be explained as a product of crustal contamination of the ID1 or DM components. The fact that NAEM seems to be a common component in lavas from all of the early NAIP (North Atlantic Igneous Province) and that it is also a mixing end...... magmas. However, 5 of the samples show signs of mixing with high-Ti melts. Although highly sensitive to crustal contamination, only little is detected in the low-Ti basalts. Isotopically the low-Ti basalts can be explained by mixing of the two end-members DM (the local depleted mantle as defined by the...

  12. Isotopic and Hydrogeological Study for the Basaltic Aquifer in Yarmouk Basin-South Syria

    International Nuclear Information System (INIS)

    The range of the compositions of environmental isotopes has been used to distinguish the sources and processes of groundwater recharge and to estimate the age of the groundwater in the Basaltic aquifer in Yarmouk basin, SW of Syria Stable isotopic data from the groundwater in the basaltic aquifer show that the groundwater in the area is derived from meteoric water. The principal recharge areas are the Mts Al-Arab and Harmon, which is reflected the mean isotopic composition of the rainwater. The groundwater from the central zone is modified by the admixture of the influx of groundwater recharged in the Mts region and direct infiltration in lower part and Laja plateau. The groundwater has undergone a significant degree of evaporation during the mechanism of recharge. The ages of groundwater corrected by Netpath model are between 2000/y old to recent age.

  13. Immiscible iron- and silica-rich melt in basalt petrogenesis documented in the Skaergaard intrusion

    DEFF Research Database (Denmark)

    Jakobsen, Jakob Kløve; Veksler, Ilya; Tegner, Christian;

    2005-01-01

    Silicate liquid immiscibility in basalt petrogenesis is a contentious issue. Immiscible iron and silica-rich liquids were reported in melt inclusions of lunar basalt and in groundmass glasses of terrestrial volcanics. In fully crystallized plutonic rocks, however, silicate liquid immiscibility has...... yet to be proven. Here we report the first finding of natural, immiscible iron- and silica-rich melts in a plutonic environment documented in the Skaergaard intrusion, East Greenland. Primary melt inclusions (now finely crystallized) in apatite are either dark or light colored. The predominant dark...... petrogenesis. Some granitic rocks may represent unmixed silica-rich melt, whereas the dense, iron-rich melt is likely to sink in the crust and could mix with hot mantle-derived magma to form unusual rocks, like ferropicrites, otherwise interpreted as products of heterogeneous mantle sources....

  14. Testing of candidate waste-package backfill and canister materials for basalt

    International Nuclear Information System (INIS)

    The Basalt Waste Isolation Project (BWIP) is developing a multiple-barrier waste package to contain high-level nuclear waste as part of an overall system (e.g., waste package, repository sealing system, and host rock) designed to isolate the waste in a repository located in basalt beneath the Hanford Site, Richland, Washington. The three basic components of the waste package are the waste form, the canister, and the backfill. An extensive testing program is under way to determine the chemical, physical, and mechanical properties of potential canister and backfill materials. The data derived from this testing program will be used to recommend those materials that most adequately perform the functions assigned to the canister and backfill

  15. Post-impact mechanical characterisation of E-glass/basalt woven fabric interply hybrid laminates

    Directory of Open Access Journals (Sweden)

    2011-05-01

    Full Text Available Post-impact properties of different configurations (symmetrical and non-symmetrical of hybrid laminates including E-glass and basalt fibre composites, all with volume fraction of fibres equal to 0.38±0.02 and manufactured by RTM, have been studied. With this aim, interlaminar shear strength tests and four-point flexural tests of laminates impacted with different energies (0, 7.5, 15 and 22.5 J have been performed. Acoustic emission (AE localisation and AE evolution with applied flexural stress was studied to support impact damage characterisation, provided by SEM and transient thermography. The results indicate that a symmetrical configuration including E-glass fibre laminate as a core for basalt fibre laminate skins presents the most favourable degradation pattern, whilst intercalation of layers may bring to further improvement of the laminate properties, but also to more extended and complex damage patterns.

  16. Rapid solubility and mineral storage of CO2 in basalt

    DEFF Research Database (Denmark)

    Gislason, Sigurdur R.; Broecker, W.S.; Gunnlaugsson, E.; Snæbjörnsdóttir, S.; Mesfin, K.G.; Alfredsson, H.A.; Aradottir, E.S.; Sigfusson, B.; Gunnarsson, I.; Stute, M.; Matter, J.M.; Arnarson, M.Th.; Galeczka, I.M.; Gudbrandsson, S.; Stockman, G.; Wolff-Boenisch, D.; Stefansson, A.; Ragnheidardottir, E.; Flaathen, T.; Gysi, A.P.; Olsson, Jonas; Dideriksen, Knud; Stipp, Susan Louise Svane; Menez, B.; Oelkers, E.H.

    2014-01-01

    The long-term security of geologic carbon storage is critical to its success and public acceptance. Much of the security risk associated with geological carbon storage stems from its buoyancy. Gaseous and supercritical CO2 are less dense than formation waters, providing a driving force for it to...... escape back to the surface. This buoyancy can be eliminated by the dissolution of CO2 into water prior to, or during its injection into the subsurface. The dissolution makes it possible to inject into fractured rocks and further enhance mineral storage of CO2 especially if injected into silicate rocks...... rich in divalent metal cations such as basalts and ultra-mafic rocks. We have demonstrated the dissolution of CO2 into water during its injection into basalt leading to its geologic solubility storage in less than five minutes and potential geologic mineral storage within few years after injection [1...

  17. The human impact on natural rock reserves using basalt, anorthosite, and carbonates as raw materials in insulation products

    DEFF Research Database (Denmark)

    Dahl, Tais Wittchen; Clausen, Anders U.; Hansen, Peter B.

    2011-01-01

    Typical crustal rocks such as basalt, limestone, and anorthosite are used in stone wool insulation products. The raw materials for stone wool production are not specific to any rare mineral source but depend upon the mixture of materials having the correct chemical composition, exemplified by 40 wt......% basalt, 20 wt% anorthosite, and 40 wt% cement-bonded renewable materials. This study provides an overview of the natural cycle of these resources, including their abundances in nature, and sets the consumption by the stone wool industry and other human activities in perspective. Basalt, anorthosite, and...... exploration. Globally, anorthositic provinces comprise smaller volumes than do limestone or basalt, but still occur in sufficient amounts to supply for the production of insulation materials indefinitely. An evaluation of the modern consumption rates and reserves shows that the crustal inventories of these...

  18. Combined Thickness of the Modeled Wanapum Basalt and Vantage-Latah Interbed Geomodel Units (wnthk_f)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The wnthk_f grid represents the modeled combined thickness of the Wanapum Basalt and the Vantage/Latah interbed geomodel units at a 500 foot resolution. It is one...

  19. Aqueous Alteration Rinds in Basalt: Mineralogic Characterization from Hand Sample to Outcrop with Hyperspectral Imaging and Implications for Mars 2020

    Science.gov (United States)

    Greenberger, R. N.; Mustard, J. F.; Cloutis, E. A.; Mann, P.; Wilson, J. H.

    2014-07-01

    Hydrothermally altered lacustrine pillow basalts show strong gradients in mineralogy, chemistry, and redox state from interior to exterior at thick section, hand sample, and outcrop scales identified with hyperspectral imaging and elemental mapping.

  20. Late Carboniferous N-MORB-type basalts in central Inner Mongolia, China: Products of hydrous melting in an intraplate setting?

    Science.gov (United States)

    Pang, Chong-Jin; Wang, Xuan-Ce; Xu, Bei; Zhao, Jian-Xin; Feng, Yue-Xing; Wang, Yan-Yang; Luo, Zhi-Wen; Liao, Wen

    2016-09-01

    Petrogenesis of the ca. 310 Ma Benbatu basalts in central Inner Mongolia is crucial for constraining the evolution of the Xing'an Mongolia Orogenic Belt (XMOB), eastern segment of the Central Asian Orogenic Belt. The Benbatu basalts have low initial 87Sr/86Sr ratios (0.7042-0.7048), positive εNd(t) (+ 8.99 to + 9.24) and εHf(t) values (+ 15.38 to + 15.65), and are characterized by relatively flat rare earth element patterns and enrichment of Rb, U, Pb, Zr and Hf, but depletion of Nb, Ta, Sr and Ti, resembling those of the normal Mid-Ocean-Ridge Basalt (N-MORB). Variations of trace element ratios (e.g., Sm/Yb and La/Sm) suggest that the basalts were derived from spinel peridotites, with a melting depth of Earth recycling water in the generation of the Late Carboniferous magmatism in this region.

  1. Recent Radar Imaging Observations of the Moon: New Views of Pyrocastics, Mare Basalts, Impact Crater Deposits, and the Lunar Subsurface

    Science.gov (United States)

    Carter, L. M.; Campbell, B. A.; Morgan, G. A.; Ghent, R. R.; Neish, C. D.

    2016-05-01

    In the last decade, radars with different wavelengths have provided polarimetric imaging of the lunar surface. These data sets have yielded new information about topics such as pyroclastics, mare basalts, cryptomare, and impact ejecta and melt flows.

  2. DISCRIMINATION OF ALTERED BASALTIC ROCKS IN THE SOUTHWESTERN UNITED STATES BY ANALYSIS OF LANDSAT THEMATIC MAPPER DATA.

    Science.gov (United States)

    Davis, Philip A.; Berlin, Graydon L.; Chavez, Pat S.

    1987-01-01

    Landsat Thematic Mapper image data were analyzed to determine their ability to discriminate red cone basalts from gray flow basalts and sedimentary country rocks for three volcanic fields in the southwestern United States. Analyses of all of the possible three-band combinations of the six nonthermal bands indicate that the combination of bands 1, 4, and 5 best discriminates among these materials. The color-composite image of these three bands unambiguously discriminates 89 percent of the mapped red volcanic cones in the three volcanic fields. Mineralogic and chemical analyses of collected samples indicate that discrimination is facilitated by the presence of hematite as a major mineral phase in the red cone basalts (hematite is only a minor mineral phase in the gray flow basalts and red sedimentary rocks).

  3. A Fungal-Prokaryotic Consortium at the Basalt-Zeolite Interface in Subseafloor Igneous Crust.

    Directory of Open Access Journals (Sweden)

    Magnus Ivarsson

    Full Text Available We have after half a century of coordinated scientific drilling gained insight into Earth´s largest microbial habitat, the subseafloor igneous crust, but still lack substantial understanding regarding its abundance, diversity and ecology. Here we describe a fossilized microbial consortium of prokaryotes and fungi at the basalt-zeolite interface of fractured subseafloor basalts from a depth of 240 m below seafloor (mbsf. The microbial consortium and its relationship with the surrounding physical environment are revealed by synchrotron-based X-ray tomographic microscopy (SRXTM, environmental scanning electron microscopy (ESEM, and Raman spectroscopy. The base of the consortium is represented by microstromatolites-remains of bacterial communities that oxidized reduced iron directly from the basalt. The microstromatolites and the surrounding basalt were overlaid by fungal cells and hyphae. The consortium was overgrown by hydrothermally formed zeolites but remained alive and active during this event. After its formation, fungal hyphae bored in the zeolite, producing millimetre-long tunnels through the mineral substrate. The dissolution could either serve to extract metals like Ca, Na and K essential for fungal growth and metabolism, or be a response to environmental stress owing to the mineral overgrowth. Our results show how microbial life may be maintained in a nutrient-poor and extreme environment by close ecological interplay and reveal an effective strategy for nutrient extraction from minerals. The prokaryotic portion of the consortium served as a carbon source for the eukaryotic portion. Such an approach may be a prerequisite for prokaryotic-eukaryotic colonisation of, and persistence in, subseafloor igneous crust.

  4. Mechanical properties of basalt fiber reinforced composites prepared by partial pyrolysis of a polymer precursor

    Czech Academy of Sciences Publication Activity Database

    Černý, Martin; Glogar, Petr; Sucharda, Zbyněk

    2009-01-01

    Roč. 43, č. 9 (2009), s. 1109-1120. ISSN 0021-9983. [International Symposium on Advanced Composites /6./. Corfu, 16.05.2007-18.05.2007] R&D Projects: GA ČR GA106/05/0817 Institutional research plan: CEZ:AV0Z30460519 Keywords : basalt fiber * polysiloxane * composite Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 0.806, year: 2009 http://jcm.sagepub.com/pap.dtl

  5. The Efficiency of Basalt Fibres in Strengthening the Reinforced Concrete Beams

    OpenAIRE

    Andreea Şerbescu; Pilakoutas Kypros; N. Ţăranu

    2006-01-01

    The technique of externally bonding fibre reinforced polymer (FRP) composite laminates on the tension side of reinforced concrete (RC) beams is already widely accepted as an easy to apply, corrosion resistant and effective solution due to the high strength as well as the low weight of the composite material. The basalt fibres are produced from volcano rocks by a simple process; their applicability as reinforcing material composites utilized for plate bonding of RC beams was not enough researc...

  6. Manufacture of Green-Composite Sandwich Structures with Basalt Fiber and Bioepoxy Resin

    OpenAIRE

    J. Andrés; J. A. García-Manrique; Hoto, R.; Torres, J. P.

    2013-01-01

    Nowadays, there is a growing interest for the use and development of materials synthesized from renewable sources in the polymer composites manufacturing industry; this applies for both matrix and reinforcement components. In the present research, a novel basalt fibre reinforced (BFR) bioepoxy green composite is proposed as an environmentally friendly alternative to traditional petroleum-derived composites. In addition, this material system was combined with cork as core material for the fabr...

  7. Comparative experimental study of dynamic compressive strength of mortar with glass and basalt fibres

    OpenAIRE

    Kruszka Leopold; Moćko Wojciech; Fenu Luigi; Cadoni Ezio

    2015-01-01

    Specimen reinforced with glass and basalt fibers were prepared using Standard Portland cement (CEM I, 52.5 R as prescribed by EN 197-1) and standard sand, in accordance with EN 196-1. From this cementitious mixture, a reference cement mortar without fibers was first prepared. Compressive strength, modulus of elasticity, and mod of fracture were determined for all specimens. Static and dynamic properties were investigated using Instron testing machine and split Hopkinson pressure bar, respecti...

  8. Mechanical and thermal properties of basalt fiber reinforced poly(butylene succinate) composites

    International Nuclear Information System (INIS)

    Highlights: ► Novel basalt fiber-reinforced biodegradable poly(butylene succinate) composites have been successfully fabricated with various fiber loadings. ► The tensile and flexural properties of the PBS matrix resin are improved significantly by increasing the fiber loading in the composites. ► The impact strength of the BF/PBS composite decreases with the addition fibers primarily and increases with increasing fiber loading due to energy dissipation when the fibers are pulled out. ► Heat deflection temperature tests clearly show that the HDT of the basalt fiber reinforced PBS composites is significantly higher than the HDT of the PBS resin. - Abstract: Basalt fiber (BF) reinforced poly(butylene succinate) (PBS) composites have been fabricated with different fiber contents by a injection molding method and their tensile, flexural and impact properties, as well as thermal stability have been investigated. The tensile and flexural properties of the PBS matrix resin are improved markedly by increasing the fiber contents in the composites. The values are relatively higher than the natural fiber/PP systems reported earlier by other research groups. The heat deflection temperature (HDT) and Vicat softening temperature (VST) of the composites are significantly higher than those of the neat PBS resin. Scanning electron microscopy (SEM) conducted on the fracture surfaces of the composites reveals superior interfacial linkage between the basalt fibers and PBS matrix. The results suggest that the BF/PBS composites may be a potential candidate of PP or PP composites to manufacturing some daily commodities to solve the “white pollution” in environmental management.

  9. GEOCHEMISTRY OF BASALT AND XENOLITHS AND ITS DEEP PROCESS IN DAOXIAN COUNTY,HUNAN PROVINCE

    Institute of Scientific and Technical Information of China (English)

    KONG Hua; XI Xiao-shuang; JIN Zhen-min; HUANG De-zhi

    2001-01-01

    @@ Deep xenolith are important samples for us to know composition and nature of the deep crust.There are many new volcanos which can all kinds of xenoliths such as a lower crustal graulite,and upper mantle-derived peridolite and lherzolite.In eastern China,there occured many deep xenoliths in Mesozoic-Cenzoic alkaline basalt.Besides these,some small volcanos eruptions were founded in southern Hunan province,which age is about 132-151 Ma.

  10. Basalt fiber insulating material with a mineral binding agent for industrial use

    Science.gov (United States)

    Drozdyuk, T.; Aizenshtadt, A.; Tutygin, A.; Frolova, M.

    2016-04-01

    The paper considers a possibility of using mining industry waste as a binding agent for heat insulating material on the basis of basalt fiber. The main objective of the research is to produce a heat-insulating material to be applied in machine building in high-temperature environments. After synthetic binder having been replaced by a mineral one, an environmentally sound thermal insulating material having desirable heat-protecting ability and not failing when exposed to high temperatures was obtained.

  11. Petrology of rift-related basalts at Bombay High waters, Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Karisiddaiah, S.M.; Iyer, S.D.

    Tholeiitic basalts obtained in 6 cores from Bombay High Region (Maharashtra, India), at depths of 860-2550 m below the seabed, are of low K and high Fe types. SiO sub(2) varies from 45.68 to 50.72%, K sub(2)O 0.09 to 0.69%, TiO sub(2) 1.06 to 2...

  12. Dynamics of basaltic glass dissolution – Capturing microscopic effects in continuum scale models.

    OpenAIRE

    Edda S.P. Aradóttir, Bergur Sigfússon, Eric L. Sonnenthal, Grímur Björnsson and Hannes Jónsson

    2013-01-01

    inuum scale reactive transport models of basaltic glass dissolution. The MINC method involves dividing the system up to ambient fluid and grains, using a specific surface area to describe the interface between the two. The various grains and regions within grains can then be described by dividing them into continua separated by dividing surfaces. Millions of grains can thus be considered within the method without the need to explicity discretizing them. Four continua were used for de...

  13. Revisiting the Jurassic Geomagnetic Reversal recorded in the Lesotho Basalt (Southern Africa)

    OpenAIRE

    Prévot, Michel; Roberts, Neil; Thompson, John; Faynot, Liliane; Perrin, Mireille; Camps, Pierre

    2003-01-01

    Post-print, as published. We carried out a detailed and continuous paleomagnetic sampling of the reversed to normal geomagnetic transition recorded by some 60 consecutive flow units near the base of the Lesotho Basalt (182-184Ma). After alternating field or thermal cleaning the directions of remanence are generally well clustered within flow units. In contrast, the thermal instability of the samples did not allow to obtain reliable paleointensity determinations. The geomagnetic transition ...

  14. Ascent and eruption of basaltic magma on the earth and moon

    International Nuclear Information System (INIS)

    Geological and physical observations and constraints are applied to the development of a model of the ascent and emplacement of basaltic magma on the earth and moon. Mathematical models of the nature and motion of gas/liquid mixtures are developed and show that gas exsolution from terrestrial and lunar magmas commonly only occurs at shallow depths (less than 2 km); thus the ascent of bubble-free magma at depth can be treated separately from the complex motions caused by gas exsolution near the surface. Magma ascent is related to dike or conduit width. For terestrial basalts with negligible yield strengths and viscosities greater than 102 Ps s, widths in the range 0.2--0.6 m are needed to allow eruptions from between depths of 0.5--20 km. Fissure widths of about 4 m would be needed to account for output rates estimated for the Columbia River flood basalt eruptions. As the magma nears the surface, bubble coalescence will tend to occur, leading to intermittent explosive strombolian-style activity. For commonly occuring lunar and terrestrial basalts the magma rise speed must be greater than 0.5-1 m/s if strombolian activity is to be avoided and relatively steady fire fountaining is to take place. Terrestrial fire fountain heights are dictated by the vertical velocity of the magma/gas dispersion emerging through the vent, increasing with increasing magma gas content and mass eruption rate, and decreasing with increasing magma viscosity. Terrestrial fire fountain heights up to 500 m imply the release of up to 0.4 wt % water from the magma, corresponding to initial water contents up to 0.6 wt %. The presence of extremely long lava flows and sinuous rilles on the moon has often been cited as evidence for very high extrusion rates and thus a basic difference between terrestrial and lunar magmas and crustal environments

  15. Effect of elevated temperatures on the mechanical behavior of basalt textile reinforced refractory concrete

    International Nuclear Information System (INIS)

    Highlights: • The thermo-mechanical behavior of basalt TRC is investigated. • The fiber polymer coating can become a deterministic factor in the TRC response. • Pre-heating the TRC at 150 °C leads to a matrix–polymer interlocking mechanism. • Above 400 °C a sudden drop in the TRC tensile response is observed. - Abstract: The work in hand presents the results of an experimental investigation on the thermo-mechanical properties of a textile refractory composite reinforced with polymer coated basalt fibers under tensile loading. The composites were produced as a laminate material using basalt bi-directional fabric layers as reinforcement. A high alumina cement matrix was used in the matrix composition which was designed using the compressible packing method. A series of uniaxial tensile tests was performed under temperatures ranging from 25 to 1000 °C. The cracking mechanisms were discussed and compared to that obtained at room temperature. Thermogravimetry and X-ray diffraction analysis were used to study the deterioration/phase changes as a function of the studied temperatures. Scanning electron microscopy (SEM) was used to study the damage processes in the fiber–matrix interfaces after exposure to high temperatures. The obtained results indicated that the presence and the type of coating can become a deterministic factor in the tensile response of the composite submitted to elevated temperatures. A sudden drop in the serviceability limit state of the composite was observed above 400 °C, caused by the degradation of the polymer used as a fiber surface coating, the degradation of the basalt fiber and by the dehydration process of the refractory matrix

  16. Basalt Waste Isolation Project. Quarterly report, January 1-March 31, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Deju, R.A.

    1980-04-01

    This report addresses the technical progress for the Basalt Waste Isolation Project for the second quarter of fiscal year 1980. Seismic design values were developed for preliminary repository design purposes; 0.25 g horizontal and 0.125 g vertical maximum accelerations for surface, zero-period conditions. Preliminary seismic data indicate broad, smooth areas exist in the bedrock surface in the western portion of the Cold Creek syncline and a gently undulating bedrock surface in the eastern portion. Test results indicate hydraulic property values fall within the range previously reported for sedimentary and interflow zones in basalt formations at the Hanford Site. Preliminary results of available hydrochemical data obtained from several borehole sites indicate that little, if any, vertical mixing of groundwaters is taking place across this stratigraphic boundary. Multiple barrier studies indicate that the primary candidate canister/overpack alloys are TiCode-12, Inconel 625, Incoloy 825, and Zircaloy 2. Low-carbon steel and cast iron are among the list of secondary candidate canister alloys. Laboratory tests of borehole plug designs have shown that it is feasible to design a composite plug system that will satisfactorily seal a nuclear waste repository in Columbia River basalt. The National Lead Industries, Inc., NLI-1/2 Universal Spent Fuel Shipping Cask was selected for use in Phase II operations. Creep test results of samples of Umtanum basalt from borehole DC-6 were plotted and show the day-to-day variation in deformation versus time. The concept selection phase of repository conceptual design was completed in March 1980. A test plan for the Exploratory Shaft Test Facility was developed and is scheduled for submittal to the US Department of Energy in May 1980.

  17. Basaltic rocks behavior of the Corrientes and Entre Rios province from the alcali silice reaction

    International Nuclear Information System (INIS)

    This work is about the basaltic rocks deposits in Mesopotamia - Argentina. This material is used for dikes, flooring and art . In several of them has been developed expansive processes associated with alkali - silica reaction such as pavements of some routes. In order to evaluate the behavior of these rocks their are obtained samples from the quarries using standard methods such as petrographic, rod accelerated and dissolved silica agree with the IRA M standards

  18. Dredged basalts from the western Nazca plate and the evolution of the East Pacific Rise

    Science.gov (United States)

    Campsie, John; Leonard Johnson, G.; Rasmussen, Mogens H.; Laursen, Jens

    1984-05-01

    Ocean-floor basalts and glasses were recovered from three stations along the western Nazca plate, from a sublinear topographic feature believed to represent the proto-East Pacific Rise (EPR), and include abyssal tholeiites, FeTi-basalts and glasses, as well as transitional and little fractionated compositions. When compared with their coexisting fresh glasses, the FeTi-basalts have higher total alkalies, TiO 2 and MgO, and lower FeO *, suggesting that they have also been affected by non-oxidative post-magmatic alteration processes. The FeTi-glasses form a remarkably uniform compositional group through space and time. A little fractionated composition having an Mg-number= 73, similar to those reported from the Mathematician Ridge, has higher Na 2O and TiO 2, and slightly lower CaO than similar compositions from the slowly accreting Mid-Atlantic Ridge. The basalts and glasses reported here exhibit the compositional diversity expected for propagating rifts and probably represent more than one volcanic episode. Both geochemical and geophysical interpretations support the inference that the EPR grew from Miocene times by the progressive growth and propagation of mantle perturbations, leaving a remnant sublinear zone of rough topography characteristic of slower accretion as the trace of the proto-EPR. Continuing translations and rotations of axial segments are occurring along the EPR, probably in response to self-reorganizations of mantle flow patterns arising from rapid melting and depletion of the source regions. The data allow the inference that the youthful rift systems of the eastern Pacific are far from thermodynamic equilibrium as might be expected if such systems were to drive fundamental life processes.

  19. Lunar Meteorites: What They Tell us About the Spatial and Temporal Distribution of Mare Basalts

    Science.gov (United States)

    Basilevsky, A. T.; Neukum, G.; Nyquist, L.

    2010-01-01

    Here we analyze the chronology and statistical distribution of lunar meteorites with emphasis on the spatial and temporal distribution of lunar mare basalts. The data are mostly from the Lunar Meteorite Compendium (http://www-curator.jsc.nasa.gov/ antmet/ lmc/contents.cfm cited hereafter as Compendium) compiled by Kevin Righter, NASA Johnson Space Center, and from the associated literature. The Compendium was last modified on May 12, 2008.

  20. Perennial grasses traits as functional markers of grazing intensity in basaltic grasslands of Uruguay

    OpenAIRE

    Lezama, Felipe; CRUZ, Pablo

    2012-01-01

    Natural grasslands in the basaltic region of Uruguay are threatened by an increase in stocking rates and changes in land use. To assess the effect of grazing intensification, plant functional types are proposed as simple tools to aid the monitoring and management of vegetation. In the present study we evaluated the effect of stocking rate increase at community level taking into account plant traits of 23 dominant perennial grass species. In order to identify plant functional types, we determi...

  1. Permeability measurements and precipitation sealing of basalt in an ancient exhumed subduction-zone fault

    OpenAIRE

    Kato, Aitaro; Sakaguchi, Arito; Yoshida, Shingo; Mochizuki, Hiromine; Kaneda, Yoshiyuki

    2003-01-01

    We conducted permeability measurements of basalt sampled from an exhumed ancient fault zone in the Cretaceous Shimanto accretionary complex in Japan, in order to investigate permeability structure and evolution following shear failure. Permeability showed a strong reduction with increase in the effective confining pressure and temperature. Rapid sealing at elevated temperatures was observed during hold experiments following shear failure. The results indicate that the permeability of a subduc...

  2. Potential fossil endoliths in vesicular pillow basalt, Coral Patch Seamount, eastern North Atlantic Ocean.

    Science.gov (United States)

    Cavalazzi, Barbara; Westall, Frances; Cady, Sherry L; Barbieri, Roberto; Foucher, Frédéric

    2011-09-01

    The chilled rinds of pillow basalt from the Ampère-Coral Patch Seamounts in the eastern North Atlantic were studied as a potential habitat of microbial life. A variety of putative biogenic structures, which include filamentous and spherical microfossil-like structures, were detected in K-phillipsite-filled amygdules within the chilled rinds. The filamentous structures (∼2.5 μm in diameter) occur as K-phillipsite tubules surrounded by an Fe-oxyhydroxide (lepidocrocite) rich membranous structure, whereas the spherical structures (from 4 to 2 μm in diameter) are associated with Ti oxide (anatase) and carbonaceous matter. Several lines of evidence indicate that the microfossil-like structures in the pillow basalt are the fossilized remains of microorganisms. Possible biosignatures include the carbonaceous nature of the spherical structures, their size distributions and morphology, the presence and distribution of native fluorescence, mineralogical and chemical composition, and environmental context. When taken together, the suite of possible biosignatures supports the hypothesis that the fossil-like structures are of biological origin. The vesicular microhabitat of the rock matrix is likely to have hosted a cryptoendolithic microbial community. This study documents a variety of evidence for past microbial life in a hitherto poorly investigated and underestimated microenvironment, as represented by the amygdules in the chilled pillow basalt rinds. This kind of endolithic volcanic habitat would have been common on the early rocky planets in our Solar System, such as Earth and Mars. This study provides a framework for evaluating traces of past life in vesicular pillow basalts, regardless of whether they occur on early Earth or Mars. PMID:21875356

  3. Evolution of porosity and diffusivity associated with chemical weathering of a basalt clast

    International Nuclear Information System (INIS)

    Weathering of rocks as a result of exposure to water and the atmosphere can cause significant changes in their chemistry and porosity. In low-porosity rocks, such as basalts, changes in porosity, resulting from chemical weathering, are likely to modify the rock's effective diffusivity and permeability, affecting the rate of solute transport and thus potentially the rate of overall weathering to the extent that transport is the rate limiting step. Changes in total porosity as a result of mineral dissolution and precipitation have typically been used to calculate effective diffusion coefficients through Archie's law for reactive transport simulations of chemical weathering, but this approach fails to account for unconnected porosity that does not contribute to transport. In this study, we combine synchrotron X-ray microcomputed tomography (μCT) and laboratory and numerical diffusion experiments to examine changes in both total and effective porosity and effective diffusion coefficients across a weathering interface in a weathered basalt clast from Costa Rica. The μCT data indicate that below a critical value of ∼9%, the porosity is largely unconnected in the basalt clast. The μCT data were further used to construct a numerical pore network model to determine upscaled, effective diffusivities as a function of total porosity (ranging from 3 to 30%) for comparison with diffusivities determined in laboratory tracer experiments. By using effective porosity as the scaling parameter and accounting for critical porosity, a model is developed that accurately predicts continuum-scale effective diffusivities across the weathering interface of the basalt clast.

  4. Detection of sub-basaltic sediments by a multi-parametric joint inversion approach

    Indian Academy of Sciences (India)

    Ajay Manglik; Saurabh K Verma; K H Singh

    2009-10-01

    In many parts of the world sedimentary horizons with potential for hydrocarbon are located below flood basalt provinces.However,the presence of high velocity basaltic overburden makes delineation of sediments difficult due to the low velocity layer problem.Electrical and electromagnetic methods have been used in such scenarios because of the good electrical conductivity contrast between basalts and underlying sediments.However,mapping of the target sediments becomes difficult when the layer is thin as the data errors due to inherent noise lead to equivalent solutions.To tackle such difficult situations,a joint inversion scheme incorporating seismic reflection and refraction, magnetotelluric and deep electrical resistivity datasets is presented. Efficacy of the scheme is tested for a model comprising a thin sedimentary layer sandwiched between a thick basalt cover and a granitic basement.The results indicate that the parameters of the target sedimentary layer are either poorly resolved or equivalent solutions are obtained by the inversion of individual datasets. Joint inversions of seismic reflection (RFLS)and refraction (RFRS),or DC and MT dataset pairs provide improved results and the range of equivalent solutions is narrowed down.Combination of any three of the above datasets leads to further narrowing of this range and improvements in mean model estimates.Joint inversion incorporating all the datasets is found to yield good estimates of the structure.Resolution analysis is carried out to appraise estimates of various model parameters obtained by jointly inverting different combinations of datasets.

  5. Mechanical and thermal properties of basalt fiber reinforced poly(butylene succinate) composites

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yihe, E-mail: zyh@cugb.edu.cn [State Key Laboratory of Geological Processes and Mineral Resources, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083 (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Yu Chunxiao [State Key Laboratory of Geological Processes and Mineral Resources, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083 (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Lv Fengzhu [State Key Laboratory of Geological Processes and Mineral Resources, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083 (China); Zhang Changan; Ji Junhui [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100101 (China); Zhang Rui [State Key Laboratory of Geological Processes and Mineral Resources, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083 (China); Wang Heli [School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083 (China)

    2012-04-16

    Highlights: Black-Right-Pointing-Pointer Novel basalt fiber-reinforced biodegradable poly(butylene succinate) composites have been successfully fabricated with various fiber loadings. Black-Right-Pointing-Pointer The tensile and flexural properties of the PBS matrix resin are improved significantly by increasing the fiber loading in the composites. Black-Right-Pointing-Pointer The impact strength of the BF/PBS composite decreases with the addition fibers primarily and increases with increasing fiber loading due to energy dissipation when the fibers are pulled out. Black-Right-Pointing-Pointer Heat deflection temperature tests clearly show that the HDT of the basalt fiber reinforced PBS composites is significantly higher than the HDT of the PBS resin. - Abstract: Basalt fiber (BF) reinforced poly(butylene succinate) (PBS) composites have been fabricated with different fiber contents by a injection molding method and their tensile, flexural and impact properties, as well as thermal stability have been investigated. The tensile and flexural properties of the PBS matrix resin are improved markedly by increasing the fiber contents in the composites. The values are relatively higher than the natural fiber/PP systems reported earlier by other research groups. The heat deflection temperature (HDT) and Vicat softening temperature (VST) of the composites are significantly higher than those of the neat PBS resin. Scanning electron microscopy (SEM) conducted on the fracture surfaces of the composites reveals superior interfacial linkage between the basalt fibers and PBS matrix. The results suggest that the BF/PBS composites may be a potential candidate of PP or PP composites to manufacturing some daily commodities to solve the 'white pollution' in environmental management.

  6. Evolution of porosity and diffusivity associated with chemical weathering of a basalt clast

    Energy Technology Data Exchange (ETDEWEB)

    Navarre-Sitchler, A.; Steefel, C.I.; Yang, L.; Tomutsa, L.; Brantley, S.L.

    2009-02-15

    Weathering of rocks as a result of exposure to water and the atmosphere can cause significant changes in their chemistry and porosity. In low-porosity rocks, such as basalts, changes in porosity, resulting from chemical weathering, are likely to modify the rock's effective diffusivity and permeability, affecting the rate of solute transport and thus potentially the rate of overall weathering to the extent that transport is the rate limiting step. Changes in total porosity as a result of mineral dissolution and precipitation have typically been used to calculate effective diffusion coefficients through Archie's law for reactive transport simulations of chemical weathering, but this approach fails to account for unconnected porosity that does not contribute to transport. In this study, we combine synchrotron X-ray microcomputed tomography ({mu}CT) and laboratory and numerical diffusion experiments to examine changes in both total and effective porosity and effective diffusion coefficients across a weathering interface in a weathered basalt clast from Costa Rica. The {mu}CT data indicate that below a critical value of {approx}9%, the porosity is largely unconnected in the basalt clast. The {mu}CT data were further used to construct a numerical pore network model to determine upscaled, effective diffusivities as a function of total porosity (ranging from 3 to 30%) for comparison with diffusivities determined in laboratory tracer experiments. By using effective porosity as the scaling parameter and accounting for critical porosity, a model is developed that accurately predicts continuum-scale effective diffusivities across the weathering interface of the basalt clast.

  7. Epithermal neutron activation analysis of CR(VI)-reducer basalt-inhabiting bacteria

    International Nuclear Information System (INIS)

    Epithermal neutron activation analysis (ENAA) has been applied to studying elemental composition of Cr(VI)-reducer bacteria isolated from polluted basalts from the Republic of Georgia. Cr(VI)-reducing ability of the bacteria was examined by electron spin resonance (ESR) demonstrating that the bacteria differ in the rates of Cr(VI) reduction. A well-pronounced correlation between the ability of the bacteria to accumulate Cr(VI) and their ability to reduce Cr(V) to Cr(III) observed in our experiments is discussed. Elemental analysis of these bacteria also revealed that basalt-inhabiting bacteria are distinguished by relative contents of essential elements such as K, Na, Mg, Fe, Mn, Zn, and Co. A high rate of Cr(III) formation correlates with a high concentration of Co in the bacterium. ENAA detected some similarity in the elemental composition of the bacteria. The relatively high contents of Fe detected in the bacteria (140-340 μg/g of dry weight) indicate bacterial adaptation to the environmental conditions typical of the basalts. The concentrations of at least 12-19 different elements ranging from major- to ultratrace ones were determined in each type of bacteria simultaneously. The range of concentrations spans over 8 orders of magnitude

  8. Influence of thermal conditions on the tensile properties of basalt fiber reinforced polypropylene–clay nanocomposites

    International Nuclear Information System (INIS)

    Highlights: • We studied tensile properties of basalt fiber/nanoclay-polypropylene (BF–PPCN). • Addition of nanoclay improves the yield strength and Young’s modulus of BF–PPCN. • The tensile properties of BF–PPCN are high at low temperature (−196 °C). - Abstract: In this paper, a comparative study on the tensile properties of clay reinforced polypropylene (PP) nanocomposites (PPCN) and chopped basalt fiber reinforced PP–clay nanocomposites (PPCN-B) is presented. PP matrix are filled with 1, 3 and 5 wt.% of nanoclays. The ultimate tensile strength, yield strength, Young’s modulus and toughness are measured at various temperature conditions. The thermal conditions are included the room temperature (RT), low temperature (LT) and high temperature (HT). The basal spacing of clay in the composites is measured by X-ray diffraction (XRD). Nanoscale morphology of the samples is observed by transmission electron microscopy (TEM). Addition of nanoclay improves the yield strength and Young’s modulus of PPCN and PPCN-B; however, it reduces the ultimate tensile strength. Furthermore, the addition of chopped basalt fibers to PPCN improves the Young’s modulus of the composites. The Young’s modulus and the yield strength of both PPCN and PPCN-B are significantly high at LT (−196 °C), descend at RT (25 °C) and then low at HT (120 °C)

  9. Development and characterization of basalt-glass ceramics for the immobilization of transuranic wastes

    International Nuclear Information System (INIS)

    Basalt-based waste forms were developed for the immobilization of transuranic (TRU) contaminated wastes. The specific waste studied is a 3:1 blend of process sludge and incinerator ash. Various amounts of TRU blended waste were melted with Pomona basalt powder. The vitreous products were subjected to a variety of heat treatment conditions to form glass ceramics. The total crystallinity of the glass ceramic, ranging from 20 to 45 wt %, was moderately dependent on composition and heat treatment conditions. Three parent glasses and four glass ceramics with varied composition and heat treatment were produced for detailed phase characterization and leaching. Both parent glasses and glass ceramics were mainly composed of a continuous, glassy matrix phase. This glass matrix entered into solution during leaching in both types of materials. The Fe-Ti rich dispersed glass phase was not significantly degraded by leaching. The glass ceramics, however, exhibited four to ten times less elemental releases during leaching than the parent glasses. The glass ceramic matrix probably contains higher Fe and Na and lower Ca and Mg relative to the parent glass matrix. The crystallization of augite in the glass ceramics is believed to contribute to the improved leach rates. Leach rates of the basalt glass ceramic are compared to those of other TRU nuclear waste forms containing 239Pu

  10. K/Ar radiometric dating of basaltic rocks in Transdanubia, Hungary

    International Nuclear Information System (INIS)

    K/Ar datings were made on 39 types of Pliocene-Pleistocene basaltic rocks from Transdanubia, Hungary. The isotopic tracer technique and the isochron method for dating are presented. The radiometric data were evaluated in view of the geological position and petrographic type and character of the samples. In addition to the conventional K/Ar dates, the 40Ar/36Ar-K/36Ar isochron dates were also calculated for presumably cogenetic samples. According to the present determinations, the age of basalts erupted near Pula at the end of the middle part of the Upper Pannonian Formation is 4.15+-0.17 m.y. The basalts of some hills in the area could be assigned to the upper part of the Upper Pannonian Formation. The average K/Ar age of the Pleistocene basic volcanic rock at village Bar is 2.02+-0.14 m.y., and its isochron age is 2.11+-0.17 m.y. (author)

  11. The effect of oxygen fugacity on the solubility of carbon-oxygen fluids in basaltic melt

    Science.gov (United States)

    Pawley, Alison R.; Holloway, John R.; Mcmillan, Paul F.

    1992-01-01

    The solubility of CO2-CO fluids in a midocean ridge basalt have been measured at 1200 C, 500-1500 bar, and oxygen fugacities between NNO and NNO-4. In agreement with results of previous studies, the results reported here imply that, at least at low pressures, CO2 dissolves in basaltic melt only in the form of carbonate groups. The dissolution reaction is heterogeneous, with CO2 molecules in the fluid reacting directly with reactive oxygens in the melt to produce CO3(2-). CO, on the other hand, is insoluble, dissolving neither as carbon, molecular CO, nor CO3(2-). It is shown that, for a given pressure and temperature, the concentration of dissolved carbon-bearing species in basaltic melt in equilibrium with a carbon-oxygen fluid is proportional to the mole fraction of CO2 in the fluid, which is a function of fO2. At low pressures CO2 solubility is a linear function of CO2 fugacity at constant temperatures.

  12. Processing and Material Characterization of Continuous Basalt Fiber Reinforced Ceramic Matrix Composites Using Polymer Derived Ceramics.

    Science.gov (United States)

    Cox, Sarah B.

    2014-01-01

    The need for high performance vehicles in the aerospace industry requires materials which can withstand high loads and high temperatures. New developments in launch pads and infrastructure must also be made to handle this intense environment with lightweight, reusable, structural materials. By using more functional materials, better performance can be seen in the launch environment, and launch vehicle designs which have not been previously used can be considered. The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Polymer matrix composites can be used for temperatures up to 260C. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in the composites. In this study, continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. The oxyacetylene torch testing and three point bend testing have been performed on test panels and the test results are presented.

  13. Basaltic glass alteration in confined media: analogy with nuclear glass in geological disposal conditions

    International Nuclear Information System (INIS)

    This dissertation concerns basaltic glass alteration mechanisms and rates. Through a better understanding of the processes controlling the basaltic glass durability, this thesis attempts to establish a link between laboratory studies and volcanic glass alteration in natural environment. The methodology used here is similar to the one used for nuclear glasses. Thus, we measured for the first time the residual alteration rate of basaltic glasses. Protective effect of the alteration film is clearly established. Moreover, synthetic glass representativeness is evaluated through a study focused on the effect of iron oxidation degree on the glass structure and leaching properties. A minor effect of Fe II on the forward rate and a negligible effect on the residual rate are shown. The residual rate is extrapolated at 5 C and compared to the mean alteration rate of natural samples of ages ranging from 1900 to 107 years. Non-zeolitized natural glasses follow this linear tendency, suggesting a control of the long-term rate by clayey secondary phase precipitation. Natural environments are open environments: a parametric study was performed in order to quantify the water flow rate effect on chemical composition of the alteration layer. When applied to two natural samples, the obtained laws provide coherent results. It seems possible to unify the descriptive approach from the study of natural environments to the mechanistic approach developed at the laboratory. The next step will consist in developing a model to transpose these results to nuclear glasses. (author)

  14. Characteristics of terrestrial basaltic rock populations: Implications for Mars lander and rover science and safety

    Science.gov (United States)

    Craddock, Robert A.; Golombek, Matthew P.

    2016-08-01

    We analyzed the morphometry of basaltic rock populations that have been emplaced or affected by a variety of geologic processes, including explosive volcanic eruptions (as a proxy for impact cratering), catastrophic flooding, frost shattering, salt weathering, alluvial deposition, and chemical weathering. Morphometric indices for these rock populations were compared to an unmodified population of rocks that had broken off a solidified lava flow to understand how different geologic processes change rock shape. We found that a majority of rocks have an sphericity described as either a disc or sphere in the Zingg classification system and posit that this is a function of cooling fractures in the basalt (Zingg [1935] Schweiz. Miner. Petrogr. Mitt., 15, 39-140). Angularity (roundness) is the most diagnostic morphometric index, but the Corey Shape Factor (CSF), Oblate-Prolate Index (OPI) and deviation from compactness (D) also sometimes distinguished weathering processes. Comparison of our results to prior analyses of rock populations found at the Mars Pathfinder, Spirit, and Curiosity landing sites support previous conclusions. The observation that the size-frequency distribution of terrestrial rock populations follow exponential functions similar to lander and orbital measurements of rocks on Mars, which is expected from fracture and fragmentation theory, indicates that these distributions are being dominantly controlled by the initial fracture and fragmentation of the basalt.

  15. The Efficiency of Basalt Fibres in Strengthening the Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    Andreea Şerbescu

    2006-01-01

    Full Text Available The technique of externally bonding fibre reinforced polymer (FRP composite laminates on the tension side of reinforced concrete (RC beams is already widely accepted as an easy to apply, corrosion resistant and effective solution due to the high strength as well as the low weight of the composite material. The basalt fibres are produced from volcano rocks by a simple process; their applicability as reinforcing material composites utilized for plate bonding of RC beams was not enough researched up to now but it seems to be a cost-effective, durable and fire resistant alternative to traditional fibres. High basalt fiber’s advantages, related to physical-mechanical characteristics and cost, stipulate a new high efficient structural composite materials, which can replace asbestos, metal, timber, plastic materials, etc. The paper investigates the applicability of externally bonded Basalt Fibre Reinforced Polymer (BFRP laminates in strengthening of rectangular reinforced section of a RC beam. The influence of the cross-sectional BFRP area on service and ultimate bending moments and also on service deflection, are analysed. The procedure is based on section analysis, equilibrium of forces and compatibility of strains, considered appropriate for any type of fibres, in case of rectangular RC beams.

  16. Simulated high-level waste-basalt interaction experiments. First interim progress report

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, G.J.; Scheetz, B.E.; Komarneni, S.; Barnes, M.; Smith, C.A.; Lewis, J.F.; Smith, D.K.

    1978-03-24

    Reconnaissance experiments have shown that waste/basalt interactions are of real importance in understanding all aspects of total containment of radionuclides in a basalt repository. It has been shown that the reprocessed waste forms, calcine and glass, are relatively more reactive than the more crystalline waste forms, spent unreprocessed fuel (SURF) and supercalcine. These experiments have established the direction of future research. The remainder of the program will be concerned with longer-duration and more-detailed experiments whose emphasis will be on understanding the mechanisms of reaction. Long-duration and in-depth experiments are being initiated to establish kinetic relationships and get a better feel as to whether or not we are approaching equilibrium in our shorter-duration reconnaissance experiments. In some cases, especially at higher temperatures, it appears that we are approaching a steady-state wherein products are no longer changing. This, however, might be a metastable state. Experiments with cesium compounds thought to be present in SURF (Cs/sub 2/MoO/sub 4/), a simple cesium source (CsOH), labradorite, and ground water have shown that pollucite forms and, as a result, fixes 86 to 99% of the cesium (depending upon the amount of basalt present.

  17. Edifice growth, deformation and rift zone development in basaltic setting : insights from Piton de la Fournaise shield volcano (Reunion Island)

    OpenAIRE

    Michon, L.; Cayol, V.; Letourneur, L.; PELTIER, A.; Villeneuve, Nicolas; Staudacher, T.

    2009-01-01

    The overall morphology of basaltic volcanoes mainly depends on their eruptive activity (effusive vs. explosive), the geometry of the rift zones and the characteristics of both endogenous and exogenous growth processes. The origin of the steep geometry of the central cone of Piton de la Fournaise volcano, which is unusual for a basaltic effusive volcano, and its deformation are examined with a combination of a detailed morphological analysis, field observations, GPS data from the Piton de la F...

  18. Magma crystallization and viscosity : a study of molten basalts from the Piton de la Fournaise volcano (La Reunion island)

    OpenAIRE

    Villeneuve, Nicolas; D. R. Neuville; Boivin, P.; Bacheery, P.; Richet, P.

    2008-01-01

    The viscosity of three molten basalts produced by fusion of lavas issued from different eruptions of the Piton de la Fournaise (La Reunion island) has been investigated above the liquidus and at high degrees of supercooling. For all basalts. crystallization took place rapidly above the glass transition range, which made static measurements problematic because of time-dependent, non-Newtonian rheology. By contrast, reproducible results were obtained in dynamic measurements made at a constant h...

  19. Summary and evaluation of hydraulic property data available for the Hanford Site upper basalt confined aquifer system

    Energy Technology Data Exchange (ETDEWEB)

    Spane, F.A. Jr.; Vermeul, V.R.

    1994-09-01

    Pacific Northwest Laboratory, as part of the Hanford Site Ground-Water Surveillance Project, examines the potential for offsite migration of contamination within the upper basalt confined aquifer system. For the past 40 years, hydrologic testing of the upper basalt confined aquifer has been conducted by a number of Hanford Site programs. Hydraulic property estimates are important for evaluating aquifer flow characteristics (i.e., ground-water flow patterns, flow velocity, transport travel time). Presented are the first comprehensive Hanford Site-wide summary of hydraulic properties for the upper basalt confined aquifer system (i.e., the upper Saddle Mountains Basalt). Available hydrologic test data were reevaluated using recently developed diagnostic test analysis methods. A comparison of calculated transmissivity estimates indicates that, for most test results, a general correspondence within a factor of two between reanalysis and previously reported test values was obtained. For a majority of the tests, previously reported values are greater than reanalysis estimates. This overestimation is attributed to a number of factors, including, in many cases, a misapplication of nonleaky confined aquifer analysis methods in previous analysis reports to tests that exhibit leaky confined aquifer response behavior. Results of the test analyses indicate a similar range for transmissivity values for the various hydro-geologic units making up the upper basalt confined aquifer. Approximately 90% of the calculated transmissivity values for upper basalt confined aquifer hydrogeologic units occur within the range of 10{sup 0} to 10{sup 2} m{sup 2}/d, with 65% of the calculated estimate values occurring between 10{sup 1} to 10{sup 2} m{sup 2}d. These summary findings are consistent with the general range of values previously reported for basalt interflow contact zones and sedimentary interbeds within the Saddle Mountains Basalt.

  20. Summary and evaluation of hydraulic property data available for the Hanford Site upper basalt confined aquifer system

    International Nuclear Information System (INIS)

    Pacific Northwest Laboratory, as part of the Hanford Site Ground-Water Surveillance Project, examines the potential for offsite migration of contamination within the upper basalt confined aquifer system. For the past 40 years, hydrologic testing of the upper basalt confined aquifer has been conducted by a number of Hanford Site programs. Hydraulic property estimates are important for evaluating aquifer flow characteristics (i.e., ground-water flow patterns, flow velocity, transport travel time). Presented are the first comprehensive Hanford Site-wide summary of hydraulic properties for the upper basalt confined aquifer system (i.e., the upper Saddle Mountains Basalt). Available hydrologic test data were reevaluated using recently developed diagnostic test analysis methods. A comparison of calculated transmissivity estimates indicates that, for most test results, a general correspondence within a factor of two between reanalysis and previously reported test values was obtained. For a majority of the tests, previously reported values are greater than reanalysis estimates. This overestimation is attributed to a number of factors, including, in many cases, a misapplication of nonleaky confined aquifer analysis methods in previous analysis reports to tests that exhibit leaky confined aquifer response behavior. Results of the test analyses indicate a similar range for transmissivity values for the various hydro-geologic units making up the upper basalt confined aquifer. Approximately 90% of the calculated transmissivity values for upper basalt confined aquifer hydrogeologic units occur within the range of 100 to 102 m2/d, with 65% of the calculated estimate values occurring between 101 to 102 m2d. These summary findings are consistent with the general range of values previously reported for basalt interflow contact zones and sedimentary interbeds within the Saddle Mountains Basalt