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Search Results: 1 - 10 of 95 matches for " ultramafic hornfelse "
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Ultramafic Hornfelses in Central Iran Ophiolites
Ghodrat Torabi
Journal of Applied Sciences , 2008,
Abstract: There are leucocratic gabbro intrusions in serpentinized mantle peridotites of Central Iran ophiolites (Jandaq, Anarak, Naein and Ashin-Zavar). In contacts of gabbro intrusions and serpentinized mantle peridotites, ultramafic hornfelses are formed by contact metamorphism. These ultramafic hornfelses are different with host mantle peridotite in petrography, texture and mineral chemistry. Two-pyroxene thermometry of hornfelses and intact mantle peridotites that are far from contact metamorphism, present 987 and 1200°C, respectively. To occuring the reaction between the gabbro intrusions and mantle peridotites, the host rock should be serpentinized previously.
Nickel uptake and intracellular localization in Cupriavidus pauculus KPS 201, native to ultramafic ecosystem  [PDF]
Arundhati Pal, A. K. Paul
Advances in Bioscience and Biotechnology (ABB) , 2010, DOI: 10.4236/abb.2010.14036
Abstract: The nickel-resistant bacterium, Cupriavidus pauculus KPS 201 was isolated from the rhizosphere of Rinorea bengalensis (Wall.) O. K. endemic to metal-percolated ultramafic ecosystem of Andaman, India. This study investigates nature of Ni resistance, growth associated uptake and localization of Ni in cellular compartments of KPS 201. Growth kinetics of C. pauculus KPS 201 exhibited a typical inducible Ni resistance in Ni-supplemented (1.0-10.0 mM) Tris-minimal medium. The Ni-induced cells showed a high degree of Ni resistance and accumulated a maximum of 29.3 µM Ni/g protein after 48 h of growth in 5 mM Ni. The accumulated Ni was preferentially retained (90.6%) in the periplasm and was associated with the expression of two periplasmic proteins (74 and 66 kDa) under Ni-induced condition. Inducible nickel resistance in C. pauculus KPS 201 may possibly be due to extracytoplasmic binding and accumulation coupled with expression of specific periplasmic proteins. These findings will provide an insight in understanding metal-microbe interaction in geogenous environments and their exploitation in bioremediation of heavy metal pollutants.
The age of the Gaojiacun mafic-ultramafic intrusive complex in the Yanbian area, Sichuan Province: Geochronological constraints by U-Pb dating of single zircon grains and40Ar/39Ar dating of hornblende
Weiguang Zhu,Hailin Deng,Bingguang Liu,Chaoyang Li,Yu Qin,Yaonan Luo,Zhide Li,Daohui Pi
Chinese Science Bulletin , 2004, DOI: 10.1007/BF03184040
Abstract: The Gaojiacun mafic-ultramafic intrusive complex in the Yanbian area, Sichuan Province, is a stratiform intrusive body that has undergone intensive magmatic differentiation. This intrusive body involves two magmatic accumulating cycles. Systematic U-Pb dating of single zircon grains and40Ar/39Ar dating of hornblende were conducted, and the results showed that the age of hornblende gabbro, which was formed at the main phase of intrusion of the Gaojiacun intrusive complex, is 840–5 Ma, casting doubt on the concept of “Yanbian Ophiolite”. It is believed that the formation of the Gaojiacun intrusive complex seems to be related to a super-mantle plume underneath the super-continent Rodinia. The above research results are helpful for us to get a better understanding of the characteristics of Neoproterozoic tectonic evolution of the Yanbian area in Sichuan Province.
M. Tufaila,Bambang Hendro Sunarminto,Dja'far Shiddieq,Abdul Sykur
Agrivita : Journal of Agricultural Science , 2011,
Abstract: Oil palm plantation in Langgikima was mostly grown in soils derived from ultramfic rocks which contain low productivity. Therefore, a study was required to determine the charac-teristics of soils evolved from ultramafic rocks evaluated from the aspects of soil formation and classification as well as land suitability for oil palm extensification. Soil observation in field had been carried out in locations of oil palm plantation with slope gradient < 15%, with ultramafic bedrocks (harzburgite, serpentinite, and olivine websterite). Soils from ultramafic rocks were characterized by almost acid to neutral soil reaction, poor nutrient content available (N, P, and K) and exchangeable base cations, with very low to low CEC, low to medium BS, and clay minerals dominated by goethite and magnetite. Soils from harzburgite and serpentinite rocks were classified as Acrustoxic Kanhaplustults while those from olivine websterite rocks were classified as Rhodic Kanhaplustalfs. Nowadays, soils from ultramafic rocks were unsuitable (N2) for oil palm with the very low level of available P as the main limiting factor. Therefore, efforts on soil management were necessary to be performed by adding suitable organic materials and fertilizers based on soil characteristics and crops’ needs.
Tectonic Setting of the Cu-Ni Sulfide-Bearing Mafic-Ultramafic Complexes in Northern Jilin Province, NE China  [PDF]
Dacheng Jia, Shen Liu, Hong Zhong, Guangying Feng, Youqiang Qi, Wen Gao, Xiao Zhang, Tao Jiang, Yongxin Mao
International Journal of Geosciences (IJG) , 2013, DOI: 10.4236/ijg.2013.42030

There are series of Cu-Ni sulfide-bearing mafic-ultramafic intrusions widespread in north JilinProvince,Northeastern China. The intrusions formed in Xing’an-Mongolian Orogenic Belt near to the northeastern margin of North China Craton. The complexes were formed in almost same period according to the zircon U-Pb dating reported recently, which means that the complexes were formed in same tectonic period and belong to one tectonic magmatic event. The rock assemblages are different from the ophiolite type and Yidun type in orogenic belt. The mafic-ultramafic complexes formed in the range from 217 Ma to 232 Ma coeval with A-type granites in the area, which formed bimodal igneous rock assemblage. According to the regional angular unconformities, there were existed the orogenies of Caledonian, Hercynian, Early Indosinian, Late Indosinian and Yanshanian. The Early Indosinian coeval with orogenic I-type granites and sanukitie that suggesting the lithosphere thickening in the extrusion tectonic setting of orogenic processes, however the Late Indosinian coeval with bimodal igneous rock assemblage that suggesting the lithosphere thinning in the extension tectonic setting of post-orogenic processes in the Xing’an-Mongolian Orogenic Belt. Chemical composition of the mafic-ultramafic rocks has the characteristics of high-Mg and low-K tholeiites related with inter-continental post-orogenic tectonic setting. The trace elements indicate their formed in conditions of continental extension belt or initial rift and has the characteristics of revolution from

Characterisation of dissolved organic compounds in hydrothermal fluids by stir bar sorptive extraction - gas chomatography - mass spectrometry. Case study: the Rainbow field (36°N, Mid-Atlantic Ridge)
Cecile Konn, Jean-Luc Charlou, Jean-Pierre Donval, Nils G Holm
Geochemical Transactions , 2012, DOI: 10.1186/1467-4866-13-8
Abstract: Organic geochemistry is of major importance in both geosciences and life sciences [1]. Investigation, identification and quantification of organic compounds (e.g., biomarkers, prebiotic molecules, hydrocarbons) help in understanding the evolution of the Earth and constraining biogeochemical processes that occurred or are still occurring on Earth. The organic geochemistry of rivers, lakes, estuaries, sedimentary basins, terrestrial rocks and oil reservoirs is being extensively studied. Despite the likely significant impact of hydrothermal circulation on the ocean global energy and matter fluxes and the implication of hydrothermal systems in major issues such as the origin of life [2,3], publications on the organic geochemistry of hydrothermal systems are rare. The literature comprises a few studies devoted to the organic contents of hydrothermal sulphide deposits [4], serpentinites [5], carbonate chimneys [6,7] and sediments [8]. In terms of fluids, the abiotic synthesis of dissolved hydrocarbon gases [9-11] as well as the presence of larger dissolved hydrocarbons and other organic molecules [12-14] in fluids from ultramafic-hosted systems at slow spreading ridges has been reported.Hydrothermal vents are found both on land (e.g. geysers, hot springs) and on the seafloor at Mid-Ocean Ridges (MOR), back arc basins and subduction zones. During hydrothermal circulation, seawater heats up and interacts with rocks in the hot Earth’s crust and mantle. Hydrothermal systems are the places where this modified seawater is expelled as hydrothermal fluids. Water-rock interactions generate gases (CH4, H2, H2S), whereas, major and minor elements such as Fe, Mn, Ca, Li, K, Na, Cl, Si are exchanged between rocks and water. These chemical entities may dissolve in the fluids or precipitate (metal oxide particle). Concentrations in the aqueous phase vary depending on lithologies (rock assemblages), processes that occur during hydrothermal circulation and physico-chemical conditions. For
Topolitossequências de solos do Alto Paranaíba: atributos físicos, químicos e mineralógicos
Rolim Neto, Fernando Cartaxo;Schaefer, Carlos Ernesto G.R;Fernandes Filho, Elpidio Inácio;Corrêa, Marcelo Metri;Costa, Liovando Marciano da;Parahyba, Roberto da Boa Viagem;Guerra, Sergio Monthezuma Santoianni;Heck, Richard;
Revista Brasileira de Ciência do Solo , 2009, DOI: 10.1590/S0100-06832009000600028
Abstract: little is known bout the pedogenetic differentiation in alto paranaíba, western minas gerais, brazil, when materials with such a variety of chemical compositions as tufite, alkaline-ultramafic igneous rocks and carbonatites are compared, which are all found in this region. the purpose of this study was to characterize the physical, chemical and mineralogical properties of three representative soil topolitosequences of the alto paranaíba region. therefore, 11 soil profiles were described and collected in the serra do salitre, patrocínio and coromandel counties, representing the influence of mafic-ultramafic bodies along the geological interface between bambuí and araxá groups. soil samples were routinely analyzed for physical and chemical properties, besides determinations of fe, al and si after sulfuric extraction; fe after extraction by dcb and oxalate; fe, ca, mg, k, p, ti, and other heavy metals after total digestion (triacid attack); and determination of the different components in the clay fraction by drx. the latosols (oxisols) of the alto paranaíba are extremely weathered and have very low ki and kr indexes, indicators of soils with high iron and aluminum oxides contents, with no defined relationship with the underlying parent materials, indicating intense pedoturbation and mixture with alloctonous materials. the geochemical signatures of the ultramafic nature are the unusual high content of cr, ni, mn, fe, and mg. the clay fraction mineralogy of the latosols shows the coexistence of vhe, kaolinite, gibbsite, and anatase, indicating a polycyclic genesis of the minerals from the finer fraction and the high weathering degree. in the cambisols, the current rapid desilification indicates the coexistence of gibbsite and iron oxides with smectites and illite because of the fast weathering in the silicon-poor mafic or alkaline-ultramafic rock substrates.
Geología y geofísica del cuerpo máfico-ultramáfico Las Ca?as, Provincia de San Luis
Ortiz Súarez,Ariel; Morosini,Augusto; Ulacco,Humberto; Carungo Durán,Andrés;
Serie correlaci?3n geol?3gica , 2012,
Abstract: las ca?as is an elongated stock located to the ne of san luis province. its structure is concordant with that of the country rock and has a size of 800 m wide by 2 km long, located in schists belonging to the las aguadas metamorphic complex (conlara metamorphic complex) with n 20o - 30o schistosity and an eastward high angle dip. the predominant facies is a gabbro that shows magmatic stratification and contains ultramafic sectors of up to 50 m in diameter; in some cases the rock is a pyroxenic hornblendite formed by poikilitic amphibole crystals with inclusions of clinopyroxene, altered olivine and opaque minerals. these rocks show alteration and mineralization of ni, cr, fe, zn and platinum group elements. the geomagnetic terrestrial survey reveals an anomaly in the mineralized zone that coincides with the ultramafic rocks, with positive and negative peaks of 1955 and -480 nt that are close to each other. contrasts of approximately 500 in nt amplitude characterize the igneous body without mineralization, whereas the metamorphic host rocks rarely exceed 100 nt. the geochemical features indicate that the las ca?as body is formed by two groups of rocks, one with high values of mgo and the other predominantly tholeitic, with the former case possessing between 2 and 22 ppb of pt or pd.

科学通报(英文版) , 1992,
Toxic Effects of Serpentine Soils on Plant Growth
Kim, Jeong-Myeong,Jae-Kuk Shim
Journal of Ecology and Field Biology , 2008,
Abstract: Serpentine soils are distributed in a small area in Korea, and generally exhibit high contents ofNi, Cr, Fe, Mn, Co and Mg. We investigated the growth of woody plants and herbs in the Andong serpentinearea, Korea. Pinus densiflora and P. rigida growing on serpentine soils have high contents of Fe, Mg, Ni andCo, with contents approximately twice as high as those of non-serpentine plants. Tree species on serpentinesoil also had lower ratios of tree height/DBH than trees in a control area. In greenhouse culture experimentson two bodenvag herb species, Setaria viridis and Cymbopogon tortilis, the biomass of the plants was significantlyaffected by soil type but not by seed origins. After 66 days, the growth of S. viridis and C. tortilis seedlingswas significantly inhibited in serpentine soil, and the dry weight of each species showed significant negativecorrelations with soil heavy metal contents (Ni, Co and Cr). These results suggest that the growth of plants wasinhibited by properties of the serpentine soil, and in particular, their high heavy metal concentration, whichinduced dwarfing in woody plants and reduction of total plant biomass in herbs.
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