Хх симпозиум по геохимии изотопов им. Виноградова А. П. 12-14 ноября 2013 года - shikardos.ru o_O
Главная
Поиск по ключевым словам:
Похожие работы
Хх симпозиум по геохимии изотопов им. Виноградова А. П. 12-14 ноября 2013 года - страница №1/3

ХХ Симпозиум по геохимии изотопов им. Виноградова А.П.

12-14 ноября 2013 года

1. INVESTIGATION OF PRODUCTION OF THE THERAPEUTIC RADIOISOTOPE 165ER BY PROTON INDUCED REACTIONS ON ERBIUM IN COMPARISON WITH OTHER PRODUCTION ROUTES
Tárkányi F., Takács S., Ditrói F., Király B., Hermanne A., Baba M., Ohtsuki T., Kovalev S.F., Ignatyuk A.V.
Applied Radiation and Isotopes. 2009. Т. 67. № 2. С. 243-247.

2. LIMITATION OF THE LONG-LIVED 121TE CONTAMINANT IN PRODUCTION OF 123I THROUGH THE 124XE(P,X) ROUTE


Hermanne A., Adam Rebeles R., Tarkanyi F., Takacs S., Ignatyuk A., Spellerberg S., Schweikert R.
Applied Radiation and Isotopes. 2011. Т. 69. № 2. С. 358-368

3. HIGH YIELD PRODUCTION OF THE MEDICAL RADIOISOTOPE 167TM BY THE 167ER(D,2N) REACTION


Hermanne A., Adam Rebeles R., Tárkányi F., Takács S., Spahn I., Ignatyuk A.V.
Applied Radiation and Isotopes. 2011. Т. 69. № 2. С. 475-481.

4. Zaichick S., Zaichick V.


TRACE ELEMENTS OF NORMAL, BENIGN HYPERTROPHIC AND CANCEROUS TISSUES OF THE HUMAN PROSTATE GLAND INVESTIGATED BY NEUTRON ACTIVATION ANALYSIS//
Applied Radiation and Isotopes. 2012. Т. 70. № 1. С. 81-87.

5. Tárkányi F., Takács S., Ditrói F., Hermanne A., Spahn I., Ignatyuk A.V.


ACTIVATION CROSS-SECTIONS OF PROTON INDUCED NUCLEAR REACTIONS ON THULIUM IN THE 20-45MEV ENERGY RANGE//
Applied Radiation and Isotopes. 2012. Т. 70. № 1. С. 309-314

6. Al-Abyad M., Abdel-Hamid A.S., Seddik U., Tárkányi F., Ditrói F., Takács S., Bashter I.I.


CROSS-SECTION MEASUREMENTS AND NUCLEAR MODEL CALCULATION FOR PROTON INDUCED NUCLEAR REACTION ON ZIRCONIUM//
Applied Radiation and Isotopes. 2012. Т. 70. № 1. С. 257-262.

7. Krmar M., Jovančević N., Nikolić D.


MEASUREMENT OF56FE ACTIVITY PRODUCED IN INELASTIC SCATTERING OF NEUTRONS CREATED BY COSMIC MUONS IN AN IRON SHIELD//
Applied Radiation and Isotopes. 2012. Т. 70. № 1. С. 269-273

8. Chao J.H., Lee H.P., Lee M.C., Chiu Y.J.


DEPOSITION OF BERYLLIUM-7 IN HSINCHU, TAIWAN//
Applied Radiation and Isotopes. 2012. Т. 70. № 2. С. 415-422

9. Rossouw D.D., Breeman W.A.P.


SCALED-UP RADIOLABELLING OF DOTATATE WITH68GA ELUTED FROM A SNO2-BASED68GE/68GA GENERATOR//
Applied Radiation and Isotopes. 2012. Т. 70. № 1. С. 171-175.

10. Zlatopolskiy B.D., Kandler R., Neumaier B., Mottaghy F.M.


C-(4-[18F]FLUOROPHENYL)-N-PHENYL NITRONE: A NOVEL18F-LABELED BUILDING BLOCK FOR METAL FREE [3+2]CYCLOADDITION//
Applied Radiation and Isotopes. 2012. Т. 70. № 1. С. 184-192.

11. Wong R., Iwata R., Furumoto S., Ishikawa Y., Saiki H., Ozeki E.


REACTIVITY OF ELECTROCHEMICALLY CONCENTRATED ANHYDROUS [18F]FLUORIDE FOR MICROFLUIDIC RADIOSYNTHESIS OF18F-LABELED COMPOUNDS//
Applied Radiation and Isotopes. 2012. Т. 70. № 1. С. 193-199

12. Koźmiński P., Gniazdowska E., Fuks L., Kowalska S.


'2+1' TRICARBONYLTECHNETIUM(I)/TRICARBONYLRHENIUM(I) MIXED-LIGAND COMPLEXES WITH METHYL THIOSALICYLATE AND ISOCYANIDE LIGANDS AS POTENTIAL PRECURSORS OF RADIOPHARMACEUTICALS//
Applied Radiation and Isotopes. 2011. Т. 69. № 2. С. 436-442

13. Melquiades F.L., Parreira P.S., Appoloni C.R., Silva W.D., Lopes F.


QUANTIFICATION OF METALS IN RIVER WATER USING A PORTABLE EDXRFSYSTEM//
Applied Radiation and Isotopes. 2011. Т. 69. № 2. С. 327-333.

14. Baccouche S., Trabelsi A., Al-Azmi D., Karunakara N.


APPLICATION OF THE MONTE CARLO METHOD FOR THE EFFICIENCY CALIBRATION OF CSI AND NAI DETECTORS FOR GAMMA-RAY MEASUREMENTS FROM TERRESTRIAL SAMPLES//
Applied Radiation and Isotopes. 2012. Т. 70. № 1. С. 227-232

15. Konki J., Greenlees P.T., Jakobsson U., Jones P., Julin R., Juutinen S., Ketelhut S., Hauschild K., Lopez-Martens A., Nieminen P., Nyman M., Peura P., Rahkila P., Ruotsalainen P., Sarén J., Scholey C., Sorri J., Uusitalo J., Kontro R., Mattila A. et al.COMPARISON OF GAMMA-RAY COINCIDENCE AND LOW-BACKGROUND GAMMA-RAY SINGLES SPECTROMETRY//


Applied Radiation and Isotopes. 2012. Т. 70. № 2. С. 392-396.

16. Nilchi A., Saberi R., Rasouli Garmarodi S., Bagheri A.


EVALUATION OF PAN-BASED MANGANESE DIOXIDE COMPOSITE FOR THE SORPTIVE REMOVAL OF CESIUM-137 FROM AQUEOUS SOLUTIONS//
Applied Radiation and Isotopes. 2012. Т. 70. № 2. С. 369-374.

17. Crespo M.T.


A REVIEW OF ELECTRODEPOSITION METHODS FOR THE PREPARATION OF ALPHA-RADIATION SOURCES//
Applied Radiation and Isotopes. 2012. Т. 70. № 1. С. 210-215

18. Patil B.J., Bhoraskar V.N., Dhole S.D., Chavan S.T., Pethe S.N., Krishnan R.


DESIGN OF 6MEV LINEAR ACCELERATOR BASED PULSED THERMAL NEUTRON SOURCE: FLUKA SIMULATION AND EXPERIMENT//
Applied Radiation and Isotopes. 2012. Т. 70. № 1. С. 149-155.

19. Borhani zarandi M., Amrollahi Bioki H., Mirbagheri Z.-A., Mirjalili G., Tabbakh F.


EFFECT OF CRYSTALLINITY AND IRRADIATION ON THERMAL PROPERTIES AND SPECIFIC HEAT CAPACITY OF LDPE & LDPE/EVA//
Applied Radiation and Isotopes. 2012. Т. 70. № 1. С. 1-5.

20. Alharbi A.A., Azzam A.


THEORETICAL CALCULATIONS OF THE REACTION CROSS-SECTIONS FOR PROTON-INDUCED REACTIONS ON NATURAL COPPER USING ALICE-IPPE CODE//
Applied Radiation and Isotopes. 2012. Т. 70. № 1. С. 88-98

21. Jörg G., Lierse v. Gostomski C., Amelin Y., Kossert K.PRECISE AND DIRECT DETERMINATION OF THE HALF-LIFE OF41CA//


Geochimica et Cosmochimica Acta. 2012. Т. 88. С. 51-65.

22. Biegalski S.R., Saller T., Helfand J., Biegalski K.M.F.


SENSITIVITY STUDY ON MODELING RADIOXENON SIGNALS FROM RADIOPHARMACEUTICAL PRODUCTION FACILITIES//
Journal of Radioanalytical and Nuclear Chemistry. 2010. Т. 284. № 3. С. 663-668.

23. Rivals I., Fabbri C., Euvrard G., Blanchard X.


A BAYESIAN METHOD WITH EMPIRICALLY FITTED PRIORS FOR THE EVALUATION OF ENVIRONMENTAL RADIOACTIVITY: APPLICATION TO LOW-LEVEL RADIOXENON MEASUREMENTS
Journal of Radioanalytical and Nuclear Chemistry. 2012. Т. 292. № 1. С. 141-153

24. Wan Mahmood Z.U., Yii M.-W.


MARINE RADIOACTIVITY CONCENTRATION IN THE EXCLUSIVE ECONOMIC ZONE OF PENINSULAR MALAYSIA:226RA,228RA AND228RA/226RA//
Journal of Radioanalytical and Nuclear Chemistry. 2012. Т. 292. № 1. С. 183-192.

25. Gledenov Yu.M., Sedysheva M.V., Zhang G., Liu J., Wu H., Liu X., Chen J., Khuukhenkhuu G., Szalanski P.J., Koehler P.E.


CROSS-SECTION MEASUREMENT AND ANALYSIS FOR THE SM149(N,α)ND146 REACTION AT 6.0 MEV//
Physical Review C - Nuclear Physics. 2010. Т. 82. № 1. С. 014601.

26. Stochioiu A., Bercea S., Sahagia M., Ivan C., Tudor I., Celarel A.THE MEASUREMENT OF THE NATURAL RADIATION BACKGROUND IN A SALT MINE//Romanian Journal in Physics. 2011. Т. 56. № 5-6. С. 757-761

27. Семинский К.Ж., Бобров А.А.
СРАВНИТЕЛЬНАЯ ОЦЕНКА РАДОНОВОЙ АКТИВНОСТИ РАЗНОТИПНЫХ И РАЗНОРАНГОВЫХ РАЗЛОМОВ БАЙКАЛЬСКОГО РИФТА И ЮГА СИБИРСКОЙ ПЛАТФОРМЫ//
Доклады Академии наук. 2009. Т. 427. № 4. С. 521-525.

28. Семинский К.Ж., Дэмбэрэл C., Тугарина М.А., Ганзориг Д., Борняков С.А.


ПЕРВЫЕ ОЦЕНКИ ОБЪЕМНОЙ АКТИВНОСТИ ПОЧВЕННОГО РАДОНА В РАЗЛОМНЫХ ЗОНАХ ЦЕНТРАЛЬНОЙ МОНГОЛИИ//
Доклады Академии наук. 2012. Т. 447. № 2. С. 199

29. Богушевич С.Е., Лысенко Г.Н.


СПЕКТРОСКОПИЧЕСКОЕ ИССЛЕДОВАНИЕ ТЕРМОЛИЗА СУЛЬФИТА КАЛЬЦИЯ//
Журнал неорганической химии. 2009. Т. 54. № 4. С. 674-679.

Методами ТГА, ЭПР и ИК-спектроскопии исследовано термическое превращение сульфита кальция в сульфат в воздушной атмосфере. Показано участие кристаллизационной воды CaSO3 · 0.5Н2 в образовании термоиндуцированных ион-радикалов SOhttp://elibrary.ru/itemimages/536158/11770396/fo_3_1.gif . Предложен механизм реакции термолиза.

30. Степаненко В.Ф., Скворцов В.Г., Иванников А.И., Дубов Д.В., Цыб А.Ф.
МЕТОДЫ ИНДИВИДУАЛЬНОЙ РЕТРОСПЕКТИВНОЙ ФИЗИЧЕСКОЙ ДОЗИМЕТРИИ В ПРОБЛЕМЕ ОЦЕНКИ ПОСЛЕДСТВИЙ НЕКОНТРОЛИРУЕМЫХ РАДИАЦИОННЫХ ВОЗДЕЙСТВИЙ//
Радиационная биология. Радиоэкология. 2011. Т. 51. № 1. С. 168-177.

Представлен обзор результатов разработки, верификации и применения методов индивидуальной физической ретроспективной дозиметрии населения загрязненных радионуклидами населенных пунктов, подвергшихся радиационному воздействию в результате аварии на ЧАЭС, а также на территориях в ареале Семипалатинского ядерного полигона. Даны оценки чувствительности методов физической ретроспективной дозиметрии. Приведены данные об индивидуальных дозах облучения населения, подвергшегося неконтролируемому радиационному воздействию.

31. Богданович Б.Ю., Крутиков М.Г., Нестерович А.В., Никулин Б.А., Шиканов А.Е.
ИСПОЛЬЗОВАНИЕ НЕЙТРОННЫХ ПОЛЕЙ ЛИНЕЙНЫХ УСКОРИТЕЛЕЙ НУКЛИДОВ ВОДОРОДА ДЛЯ ИССЛЕДОВАНИЯ ОБРАЗЦОВ ГОРНЫХ ПОРОД//
Ядерная физика и инжиниринг. 2010. Т. 1. № 6. С. 526-533.

В статье проведен анализ возможности использования линейных ускорителей нуклидов водорода в качестве нейтронных генераторов для элементного анализа горных пород. Основное внимание уделено вопросам элементного анализа на золото, уран и породообразующие элементы, составляющие коллекторы продуктивных углеводородов. Обсуждаются возможные варианты реализации рассматриваемых методик.

32. Zhou, Jiaxi; Huang, Zhilong; Zhou, Meifu; et al.

Constraints of C-O-S-Pb isotope compositions and Rb-Sr isotopic age on the origin of the Tianqiao carbonate-hosted Pb-Zn deposit, SW China //ORE GEOLOGY REVIEWS  Volume: 53   Pages: 77-92    SEP 2013
The Tianqiao Pb-Zn deposit in the western Yangtze Block, southwest China, is part of the Sichuan-Yunnan-Guizhou (SYG) Pb-Zn metallogenic province. Ore bodies are hosted in Devonian and Carboniferous carbonate rocks, structurally controlled by a thrust fault and anticline, and carried about 0.38 million tons Pb and Zn metals grading >15% Pb + Zn. Both massive and disseminated Pb-Zn ores occur either as veinlets or disseminations in dolomitic rocks. They are composed of ore minerals, pyrite, sphalerite and galena, and gangue minerals, calcite and dolomite. delta S-34 values of sulfide minerals range from +8.4 to +14.4 parts per thousand and display a decreasing trend from pyrite, sphalerite to galena (delta S-34(pyrite)>delta S-34(sphalerite)>delta S-34(galena)). We interpret that reduced sulfur derived from sedimentary sulfate (gypsum and barite) of the host Devonian to Carboniferous carbonate rocks by thermal-chemical sulfate reduction (TSR). delta C-13(PDB) and delta O-18(SMOW) values of hydrothermal calcite range from -5.3 to -3.4 parts per thousand. and +14.9 to +19.6 parts per thousand, respectively, and fall in the field between mantle and marine carbonate rocks. They display a negative correlation, suggesting that CO2 in the hydrothermal fluid was a mixture origin of mantle, marine carbonate rocks and sedimentary organic matter. Sulfide minerals have homogeneous and low radiogenic Pb isotope compositions (Pb-206/Pb-204 = 18.378 to 18.601, Pb-207/Pb-204 = 15.519 to 15.811 and Pb-208/Pb-204 = 38.666 to 39.571) that are plotted in the upper crust Pb evolution curve and overlap with that of Devonian to Carboniferous carbonate rocks and Proterozoic basement rocks in the SYG province. Pb isotope compositions suggest derivation of Pb metal from mixed sources. Sulfide minerals have Sr-87/Sr-86 ratios ranging from 0.7125 to 0.7167, higher than Sinian to Permian sedimentary rocks and Permian Emeishan flood basalts, but lower than basement rocks. Again, Sr isotope compositions are supportive of a mixture origin of Sr. They have an Rb-Sr isotopic age of 191.9 +/- 6.9Ma, possibly reflecting the timing of Pb-Zn mineralization. C-O-S-Pb-Sr isotope compositions of the Tianqiao Pb-Zn deposit indicate a mixed origin of ore-forming fluids, which have Pb-Sr isotope homogenized before the mineralization. The Permian flood basalts acted as an impermeable layer for the Pb-Zn mineralization hosted in the Devonian-Carboniferous carbonate rocks. (C) 2013 Elsevier B.V. All rights reserved.

33. Jemmali, Nejib; Souissi, Fouad; Carranza, Emmanuel John M.; et al.



Sulfur and lead isotopes of Guern Halfaya and Bou Grine deposits (Domes zone, northern Tunisia): Implications for sources of metals and timing of mineralization //

ORE GEOLOGY REVIEWS  Volume: 54   Pages: 17-28    OCT 2013


The Pb-Zn ore deposits in the Guern Halfaya and Bou Grine areas (northern Tunisia) are hosted mainly by dolostones in the contact zone between Triassic and Upper Cretaceous strata and by Upper Cretaceous limestones. The deposits occur as lenticular, stratiform, vein, disseminations and stockwork ore bodies consisting of sphalerite, galena, pyrite, chalcopyrite and sulfosalt (gray copper). Barite and celestite dominate the gangue, with lesser calcite. The delta S-34 values of barite and celestite (12.7-15.0 parts per thousand) at the Oum Edeboua mine are consistent with the reduction of sulfates in Triassic evaporites within the study area (12.8 < delta S-34 < 14.0 parts per thousand). The delta S-34 values in base-metal sulfides from both study areas (2.6-9.5 parts per thousand) and the presence of bacterial relics suggest involvement of bacterially-mediated sulfate reduction in the mineralization. The present Pb isotope data are homogeneous with Pb-206/Pb-204, Pb-207/Pb-204 and Pd-208/Pb-204 ratios of 18.723-18.783, 15.667-15.685 and 38.806-38.889, respectively, which suggest a single source reservoir of Pb at depth in the upper crust. The syn-diagenetic mineralization in the Bahloul Formation and the calculated age from the Pb isotopic data suggest an Upper Cretaceous age for the Pb-Zn deposits in the Guern Halfaya and Bou Grine areas. During this period, NE-SW to ENE-WSW trending regional extensional tectonic structures likely favored migration of mineralizing fluids and eventual deposition at Guern Halfaya and Bou Grine.

34. Zhang, Jing; Chen, Yan-Jing; Pirajno, Franco; et al. Geology, C-H-O-S-Pb isotope systematics and geochronology of the Yindongpo gold deposit, Tongbai Mountains, central China: Implication for ore genesis //

ORE GEOLOGY REVIEWS  Volume: 53   Pages: 343-356   DOISEP 2013
The Yindongpo gold deposit is located in the Weishancheng Au-Ag-dominated polymetallic ore belt in Tongbai Mountains, central China. The ore bodies are stratabound within carbonaceous quartz-sericite schists of the Neoproterozoic Waitoushan Group. The ore-forming process can be divided into three stages, represented by early barren quartz veins, middle polymetallic sulfide veinlets and late quartz-carbonate stockworks, with most ore minerals, such as pyrite, galena, native gold and electrum being formed in the middle stage. The average delta O-18(water) values changed from 9.7 parts per thousand in the early stage, through 4.9 parts per thousand in the middle stage, to -5.9 parts per thousand in the late stage, with the delta D values ranging between -65 parts per thousand and -84 parts per thousand. The delta C-13(CO2) values of ore fluids are between -3.7 parts per thousand and +6.7 parts per thousand, with an average of 1.1 parts per thousand. The H-O-C isotope systematics indicate that the ore fluids forming the Yindongpo gold deposit were probably initially sourced from a process of metamorphic devolatilization, and with time gradually mixed with meteoric water. The delta S-34 values range from -0.3% to +5.2 parts per thousand, with peaks ranging from +1 parts per thousand to +4 parts per thousand. Fourteen sulfide samples yield Pb-206/Pb-204 values of 16.990-17.216, Pb-207/Pb-204 of 15.419-15.612 and Pb-208/Pb-204 of 38.251-38.861. Both S and Pb isotope ratios are similar to those of the main lithologies of the Waitoushan Group, but differ from other lithologic units and granitic batholiths in the Tongbai area, which suggest that the ore metals and fluids originated from the Waitoushan Group. The available K-Ar and Ar-40/Ar-39 ages indicate that the ore-forming process mainly took place in the period of 176-140 Ma, during the transition from collisional compression to extension and after the closure of the oceanic seaway in the Qinling Orogen. The Yindongpo gold deposit is interpreted as a stratabound orogenic-style gold system formed during the transition phase from collisional compression to extension.

The ore metals in the Waitoushan Group were extracted, transported and then accumulated in the carbonaceous sericite schist layer. The carbonaceous sericite schist layer, especially at the junction of collapsed anticline axis and fault structures, became the most favorable locus for the ore bodies.

35. Dong, Guochen; Santosh, M.; Li, Shengrong; et al.

Mesozoic magmatism and metallogenesis associated with the destruction of the North China Craton: Evidence from U-Pb geochronology and stable isotope geochemistry of the Mujicun porphyry Cu-Mo deposit //ORE GEOLOGY REVIEWS  Volume: 53   Pages: 434-445   DOI: 10.1016/j.oregeorev.2013.02.006   Published: SEP 2013
The North China Craton (NCC) provides a classic example of lithospheric destruction and refertilization. The timing and duration of magmatism and related metallogenesis associated with the destruction process are pivotal to understanding the geodynamic controls. In this study, we present zircon U-Pb and Hf data, Re-Os ages, and He, Ar, Pb and S isotope data from the Mujicun porphyry Cu-Mo deposit in the northern Taihang Mountains within the Central Orogenic Belt of the NCC. We constrain the timing of magmatism as 144.1 +/- 1.2 Ma from zircon U-Pb data on the diorite porphyry that hosts Cu-Mo mineralization. Another U-Pb age of 139.7 +/- 1.4 Ma was obtained from an epidote skarn that is located in the contact zone between the porphyry and its wall rocks. These data and five Re-Os molybdenite ages that range from 142.7 +/- 2.0 Ma to 138.5 +/- 1.9 Ma suggest that magmatism and mineralization occurred in about five million year duration from similar to 143 Ma to similar to 138 Ma. The He, Ar, Pb and, Hf data suggest that magmatism involved recycled Neoarchean lower crustal components, with input of heat and volatiles from an upwelling mantle. The Mujicun porphyry and associated mineralization provide a typical example for magmatism and metallogeny associated with lithospheric thinning in the NCC.

36. Kaljo, Dimitri; Martma, Tonu; Grytsenko, Volodymyr; et al.



Pridoli carbon isotope trend and upper Silurian to lowermost Devonian chemostratigraphy based on sections in Podolia (Ukraine) and the East Baltic area //ESTONIAN JOURNAL OF EARTH SCIENCES  Volume: 61   Issue: 3   Pages: 162-180    SEP 2012
Insufficient knowledge of carbon isotope cycling in the latest Silurian initiated the study of two regions at the western and southwestern margins of Baltica in order to obtain a more complete picture about the carbon isotope trend through the Pridoli. Shallow and open shelf carbonate rocks of the Dniester River outcrops and Kotuzhiny core in Podolia and deep shelf rocks of the East Baltic area, especially the Lithuanian cores, were studied for bulk-rock isotope analysis. The data sets of both regions begin with the mid-Ludfordian excursion and include also some part of the lowermost Devonian. The data show a new minor twin positive delta C-13 excursion (peak values 0.8-1.7 parts per thousand) in the upper Ludfordian. The Pridoli carbon isotope trend begins with a low of negative delta C-13 values, succeeded by the lower to middle Pridoli 'stability' interval (variable values below or close to 0 parts per thousand with a slight rising trend). The upper Pridoli begins with a medium to major excursion (peak values 2.3-4.5 parts per thousand), which reflects the pattern of the carbon isotope trend on the west of the Baltica palaeocontinent. Its wider significance awaits confirmation from observations elsewhere. The carbon isotope excursion at the Silurian Devonian boundary, named here the SIDE excursion (its delta C-13 values range from 1.6 parts per thousand in deep shelf settings to 3.8 parts per thousand in shallower ones and 4.5 parts per thousand in brachiopod shells), has been traced on several continents, and now also in Baltica. This excursion can serve as a well-dated global chemostratigraphic correlation tool. The shape of the excursion indicates the completeness of the studied section. We conclude that carbon isotope chemostratigraphy may contribute to subdividing the Pridoli Series into stages and that Baltica sensu lato seems to be the right place for such a development.

37. Kaljo, Dimitri; Maennik, Peep; Martma, Tonu; et al.



More about the Ordovician-Silurian transition beds at Mirny Creek, Omulev Mountains, NE Russia: carbon isotopes and conodonts //ESTONIAN JOURNAL OF EARTH SCIENCES  Volume: 61   Issue: 4   Special Issue: SI   Pages: 277-294  DEC 2012
Profound environmental and biodiversity changes take place in the Ordovician-Silurian boundary interval. The Mirny Creek and Neznakomka River bank sections discussed in this paper expose the upper Katian-lower Rhuddanian part of the boundary beds. The succession consists of carbonate rocks, partly with bioherms, alternating with argillaceous and siltstone packages that are well dated by graptolites. Microfossils are rare, especially in the Hirnantian, but conodonts provide some useful markers just below and above the Hirnantian stage boundaries. The Hirnantian delta C-13 trend in the Mirny Creek section is the stratigraphically longest described so far and it has a highly specific shape. The trend commenced at the first appearance datum of Normalograptus extraordinarius or slightly below this level. The main peak occurs near the middle of the N. persculptus Biozone. Samples from the Neznakomka River suggest a somewhat wider peak interval than at Mirny Creek. Detailed comparison of the Mirny and Stirnas (Latvia) delta C-13 curves shows a general similarity despite great specific features of both trends. Correlation of the delta C-13 trends from China, Baltica and North America with that at Mirny Creek reveals a great variety of shapes of the carbon isotope curve. However, its rising limb commenced, if represented, everywhere close to the beginning of the N. extraordinarius Biozone or in terms of the Baltic succession, at the bottom of the Porkuni Regional Stage. Most likely a general shape of the HICE trend is pyramidal, which is peaking in the early N. persculptus Biochrone. Differences in the values and shape of an actual curve at different localities depend on local environmental conditions, sometimes modifying the global signal rather strongly.

38. Bejaoui, J.; Bouhlel, S.; Barca, D.; et al.The Vein-type Zn-(Pb, Cu, As, Hg) mineralization at Fedj Hassene orefield, North-Western Tunisia: Mineralogy, Trace Elements, Sulfur Isotopes and Fluid Inclusions //ESTUDIOS GEOLOGICOS-MADRID  Volume: 67   Issue: 1   Pages: 5-20    2011


The Fedj Hassene district is localized at the edge of the Tuniso-Algerian border 10 km of Ghardimaou area. It consists of a Zn-Pb vein type with minor amounts of Cu-As-Hg. The total Zn reserves are about 370.000t. The mineralization occurs within subparallel fractures to the Ain El Kohla ESE-WNW fault. Host rocks consist of limestones and marly limestones of the Middle Turonian. In the principal lode of Fedj Hassene, the mineralization occurs as vein filling of massive and brecciated brown sphalerite and minor galena ore with gangue. Other trace minerals are pyrite, chalcopyrite, orpiment, realgar, smithsonite and cerussite. LA-ICP-MS analyses in sphalerites show mean contents of 0,84 wt% Fe, 0,14 wt% Cd and 0,02 wt% Mn Ore.

Fluid inclusions study in calcite and sphalerite reveals one mineralizing fluid characterized by an average salinity 23% wt NaCl with decreasing homogenisation temperature. In fact the temperature shows decrease from sphalerite to calcite. The fluid density that corresponds to trapping pressure ranges between 1.00 g/cm(3) and 1.11 g/cm(3) and pressure close to 200 bars. Microthermometric data in fluid inclusion hosted by gangue mineral presented by calcite show an average temperature of formation around 194 degrees C. These inclusions homogenized to the liquid phase between 156 degrees C and 210 degrees C and salinities values ranging from 22 to 28 wt% NaCl and an average around 23% wt NaCl.

The delta(34)S (VCDT) values of sphalerite are in the range of + 4,6 parts per thousand to 6,4 parts per thousand (average=5,6 parts per thousand). Thermo-chemical reduction of Triassic sulfate by reaction with hydro-carbons is the most probable source for the heavy and the narrow range of the delta(34)S values.

Mineralogical, geochemical of trace elements, fluid inclusions and sulfur isotopes studies allow to include the vein-type ore field of Fedj Hassene in the polymetallic (Pb-Zn-As-Hg) vein mineralization of the nappe zone in northern Tunisia and north eastern Algeria.

39. Prado, J. L.; Alberdi, M. T.; Sanchez, B.; et al.

The extinction of Equidae and Proboscidea in South America. A test using Carbon isotope data //ESTUDIOS GEOLOGICOS-MADRID  Volume: 67   Issue: 2   Pages: 363-373    2011
Carbon isotopes, preserved in 166 samples of fossil teeth and bone, provide key data for understanding the ecology of extinct horses and gomphotheres during the Plio-Pleistocene in South America. To analyze the patterns of dietary partitioning throughout this time we divided the samples into 19 groups, taking into account the genus and the age of the corresponding localities. In this study, the diets of both groups are assessed to test extinction hypotheses. The strong resource partitioning among herbivores assumed under Co-evolutionary disequilibrium hypothesis is supported by isotopic data of horses from latest Pleistocene. Hippidon and Equus had very different diets. In contrast, species of gomphotheres from late Pleistocene in South America seem to have had less specialized diets containing a broad mix of both C-3 and C-4 plants, which is in line with the dietary assumptions of the mosaic-nutrient hypothesis, but does not support the assumptions of Co-evolutionary disequilibrium hypothesis.

40. Sanchez, V.; Martin-Crespo, T.; Vindel, E.; et al.



He isotopes constraints to the origin of hydrothermal fluids: application to the fluorite mineralizations of Asturias (N Spain) //ESTUDIOS GEOLOGICOS-MADRID  Volume: 66   Issue: 1   Pages: 75-82    2010
Helium isotopes have been measured in fluorite and sulphides in order to obtain conclusive means of assessing the involvement of mantle and crustally derived volatiles in F-Ba deposits from Asturias (N of Spain). Fluorite mineralizations are hosted in Mesozoic (Permotriassic) and Paleozoic age rocks. Mineralization is composed of fluorite, barite, calcite, dolomite, quartz and sulphides, and shares the characteristics of most Mississippi Valley Type (MVT) deposits associated with rifting events related to the opening of the Atlantic Ocean. The (3)He/(4)He values of the Asturias ore fluids (<= 0,1 Ra) indicate a crustal fluid source and exclude the involvement of a mantle helium component. These values are consistent with the acceptance of the existing basinal model for MVT genesis and sedimentary brines migration, with the lack of igneous activity in the area contemporary with the mineralization, and also consistent with similar helium isotope data recorded in other fluorite deposits in Europe.

41. Rogov, Mikhail A.; Price, Gregory D.



New stratigraphic and isotope data on the Kimmeridgian-Volgian boundary beds of the Subpolar Urals, Western Siberia //GEOLOGICAL QUARTERLY  Volume: 54   Issue: 1   Pages: 33-40   Published: 2010

Начало формы



A review and new data regarding the ammonite faunas and biostratigraphy of the uppermost Kimmeridgian-lowermost Volgian of the Subpolar Urals are presented. The combined ranges of almost all ammonite genera in the lowermost Volgian of the Subpolar Urals supports the traditional point of view regarding the equivalence of the Magnum Zone with the two lowermost Bolonian Zones and with the bulk of the Klimovi Zone. This stratigraphic interpretation permits the stable isotope data (carbon and oxygen) derived from associated belemnites to be presented in context. The isotopic records from the belemnites suggest that the lower Volgian sediments of the Yatria River, Subpolar Ural Mountains were deposited in a warm marine environment consistent with a warm high latitude scenario. If reduced salinites arc invoked apparent temperatures are lowered by similar to 5 degrees C, but still remain well above freezing and are relatively warm compared to some recent modelled estimates of Late Jurassic ocean temperatures.




42. Price, Gregory D.; Passey, Benjamin H.

Dynamic polar climates in a greenhouse world: Evidence from clumped isotope thermometry of Early Cretaceous belemnites //GEOLOGY  Volume: 41   Issue: 8   Pages: 923-926    AUG 2013
Sub-arctic Cretaceous (Berriasian-late Valanginian, ca. 145-134 Ma) marine temperatures obtained from fossil mollusks (belemnites) are determined using carbonate clumped isotope thermometry, an approach based on the "clumping" of C-13 and O-18 in the carbonate mineral lattice into bonds with each other. From our analyses we infer sub-arctic Early Cretaceous marine temperatures ranging from 10 degrees C to 20 degrees C. These possibly seasonally biased, warm sub-arctic temperatures are warmer than present mean summer water temperatures at 60-65 degrees N and are therefore consistent with a warmer "greenhouse" world featuring a shallow (equable) latitudinal temperature gradient. Our combined temperature and delta O-18(belemnite) data imply seawater delta O-18 values that have a remarkably modern character in that they are similar to modern high-latitude seawater but more positive than modeled Cretaceous seawater. We identify a cooler late Valanginian interval (ca. 134 Ma) with temperatures consistent with polar regions a few degrees above freezing and also coincident with increased delta O-18 seawater values. Thus we find evidence of intervals when polar ice was unlikely, and also when polar ice was plausible. Both scenarios support the view of generally warm but dynamic polar climates during greenhouse intervals that were punctuated by periods of ice growth.

43. : Xue, Yunxing; Campbell, Ian; Ireland, Trevor R.



No mass-independent sulfur isotope fractionation in auriferous fluids supports a magmatic origin for Archean gold deposits //GEOLOGY  Volume: 41   Issue: 7   Pages: 791-794    JUL 2013
The source of the auriferous fluids that formed Archean greenstone gold deposits remains controversial; metamorphic fluids, fluids derived from felsic magmas, mantle fluids, and meteoric water have all been suggested. We report the results of ion microprobe (sensitive high-resolution ion microprobe stable isotopes) multiple sulfur isotope analyses (S-32, S-33, (3)4S) conducted to constrain the source of sulfur in four Archean gold deposits. The analyses are of pyrite samples that are genetically related to the gold mineralization from the Bellerophon, Victory, and Wallaby deposits in the Eastern Goldfield superterrane of the Yilgarn craton, Western Australia, together with sulfide from black shale from the Golden Mile deposit and St. Ives gold camp. Ore-associated pyrite from the Beattie gold deposit of the Abitibi greenstone belt of the Superior craton in Canada was measured to test whether the results obtained from the Yilgarn craton apply to other Archean gold deposits. Sulfur analyses from sulfide from shale show mass-independent fractionation (MIF) with Delta S-33 as high as +1.8 parts per thousand, whereas those from the 4 Archean gold deposits are dominated by mass-dependent fractionation, with only a minor contribution of MIF sulfur. In this respect, Archean gold deposits contrast with Archean NiS deposits, which are dominated by MIF sulfur. The absence of MIF in the pyrite from the four Archean gold deposits analyzed in this study is consistent with the auriferous fluid originating from a felsic magma or mantle source, but inconsistent with the metamorphic and meteoritic fluid hypotheses.

44. Gomes, Maya L.; Hurtgen, Matthew T.



Sulfur isotope systematics of a euxinic, low-sulfate lake: Evaluating the importance of the reservoir effect in modern and ancient oceans //GEOLOGY  Volume: 41   Issue: 6   Pages: 663-666    JUN 2013
The sulfur (S) isotope difference between sedimentary sulfate and sulfide phases preserved in sedimentary rocks (Delta S-34) has been utilized to reconstruct marine sulfate concentrations and inferentially the redox evolution of Earth's surface. These interpretations are largely based on experimental studies that indicate that microbial sulfate reduction is accompanied by a substantial kinetic isotope effect (up to 66 parts per thousand), but only at sulfate concentrations >similar to 200 mu M. In this study, we examine S isotope systematics in a modern, low-sulfate euxinic lake (similar to 100-350 mu M) and find that the calculated kinetic isotope effect associated with microbial sulfate reduction (epsilon S-34) is relatively large (similar to 23.5 parts per thousand), but preserved Delta S-34 values are considerably smaller (4.7 parts per thousand-9.9 parts per thousand). Delta S-34 values in this system are controlled by the fraction of the sulfate reservoir that is consumed during sulfate reduction and the location of pyrite formation. This reservoir effect strongly influences the S isotope composition of sulfide preserved in the rock record such that Delta S-34 values increase as a function of sulfate levels, even when sulfate concentrations are > 200 mu M and the kinetic isotope effect is expressed. These findings have important implications for reconstructing the chemical evolution of the ocean-atmosphere system throughout Earth history-not just for the Precambrian.

45. Raitzsch, Markus; Hoenisch, Baerbel



Cenozoic boron isotope variations in benthic foraminifers //GEOLOGY  Volume: 41   Issue: 5   Pages: 591-594    MAY 2013
The boron isotopic composition of seawater (delta B-11(sw)) is a prerequisite for reliably estimating past variation of seawater pH from boron isotopes in marine carbonates (delta B-11(c)). Here we compose a 50 m.y. stack of delta B-11(c) from Atlantic and Pacific Ocean deep-sea sediments, and discuss the potential effects of deep-sea pH and delta B-11(sw) on our record. Using model-based Cenozoic pH values, the inferred delta B-11(sw) values suggest an similar to 3 parts per thousand increase since the Late Eocene, superimposed on oscillating variations with amplitudes of up to 2 parts per thousand. Our estimates match existing reconstructions of delta B-11(sw), but call into question published fluid delta B-11 in halite as a recorder of delta B-11(sw).

46. Genske, Felix S.; Beier, Christoph; Haase, Karsten M.; et al.



Oxygen isotopes in the Azores islands: Crustal assimilation recorded in olivine //

GEOLOGY  Volume: 41   Issue: 4   Pages: 491-494    APR 2013


Oxygen isotope ratios of olivine have become a widely used tool for the study of magmatic systems, especially in the interpretation of source heterogeneities in mantle plume-derived ocean island basalts. The underlying assumption is that fresh minerals provide a better guide to magma delta O-18 than bulk rock analyses and that olivine is also likely to be a major phenocryst phase in primitive magmas. However, distinctions between source compositions and the effects of subsequent magma evolution have not always been thoroughly scrutinized. For the Azores samples investigated here, we can demonstrate that the delta O-18 variation (+4.84% to +5.25% Vienna standard mean ocean water) observed in the olivine phenocryst population is closely linked to evolution in the host magmas during ascent to the surface. We observe a linear, positive correlation between forsterite (Fo) content and delta O-18 in all of the individual island lava suites. This forces us to conclude that the low oxygen isotope ratios result from combined assimilation and fractional crystallization processes, the assimilant being hydrothermally (temperature > 250 degrees C) altered, lower oceanic crust. Linear regression of the measured delta O-18 olivine values to Fo(89) suggests a homogeneous mantle source with delta O-18 = +5.2 parts per thousand +/- 0.1 parts per thousand.

47. Peng, Yongbo; Bao, Huiming; Zhou, Chuanming; et al Oxygen isotope composition of meltwater from a Neoproterozoic glaciation in South China //GEOLOGY  Volume: 41   Issue: 3   Pages: 367-370    MAR 2013


The water cycle is an integral part of Earth surface dynamics, and water's oxygen-isotope composition retains information about the forcing and response of Earth's local and global climate. Water isotope signals of the recent geological past can be directly obtained from archives such as ice cores, groundwater, or pore fluid. For the more distant past, mineral proxies have to be used. Multiple episodes of global glaciation may have occurred in the Neoproterozoic Era, of which the record of oxygen-isotope composition of glacial meltwater is sparse; the few records that are derived from carbonate minerals are prone to late-burial and metamorphic alteration, and therefore subject to alternative explanations. Here we present a case in which meltwater delta O-18 is retrieved from barite (BaSO4) and malachite (Cu2CO3(OH)(2))-associated sulfate (MAS) in a diamictite in Kaiyang, Guizhou, South China. The core of our argument is based on the lowest-ever-published sulfate delta O-18 values found in the barite and MAS, reaching as low as -20.3 parts per thousand (Vienna standard mean ocean water, VSMOW). These data suggest that the water involved in the oxidative weathering of these chalcocite clasts had a delta O-18 value of -34 parts per thousand +/- 10 parts per thousand, similar to that of polar glaciers today. Excluding the possibility of glacier meltwater alteration during the past 600 m.y. after the deposition of the diamictite, the sulfate mineral assemblage reported here provides an important constraint on the nature of the Neoproterozoic glaciation that the Kaiyang diamictite represents.

48. Desaulty, Anne-Marie; Albarede, Francis



Copper, lead, and silver isotopes solve a major economic conundrum of Tudor and early Stuart Europe //GEOLOGY  Volume: 41   Issue: 2   Pages: 135-138    FEB 2013
The unrelenting economic inflation of A.D. 1515-1650 in Europe has been variously explained by the influx of silver from Mexico and the Viceroyalty of Peru (now Bolivia), the growth of the European population, and the decline of the silver market price. Silver, copper, and lead isotope analyses of A.D. 1550-1650 English coinage show a dominance of silver from Europe and Mexico, contrasting with a spectacularly small contribution from the Viceroyalty of Peru. This observation contrasts with the registration of metal production in the mines of the Spanish Americas. Hence the question: Where did Potosi silver go? This novel observation indicates that silver from Mexico was exported eastward, whereas Potosi silver flowed westward. However, aware of the Pacific route of the silver trade, scholars never agreed upon the volumes transported. Our work demonstrates that there was a Potosi-China route, and that it was largely disconnected from the Mexico-Europe routes.

49. Lange, Amy E.; Nielsen, Roger L.; Tepley, Frank J., III; et al.



Diverse Sr isotope signatures preserved in mid-oceanic-ridge basalt plagioclase //GEOLOGY  Volume: 41   Issue: 2   Pages: 279-282    FEB 2013
At mid-ocean ridges, a variety of crustal processes overprint mantle-derived melts and can obscure original mantle compositions. To address the nature of this crustal filter, we report Sr-87/Sr-86 ratios from plagioclase phenocrysts and host glasses in mid-oceanic-ridge basalts from the Juan de Fuca Ridge, Blanco Transform Zone, and the Southwest Indian Ridge. Microdrilled isotopic analyses reveal significant inter- and intracrystalline disequilibria within individual samples. These disequilibria suggest that a range of isotopically distinct melt components contribute to individual plagioclase crystals and to the magmas that transport them to the surface. Low Cl/K values both in the host glass and in plagioclase-hosted melt inclusions largely rule out incorporation of seawater-derived material as an explanation for differences in Sr-87/Sr-86. Instead, the observed heterogeneity implies derivation of magmas from isotopically diverse mantle sources. Importantly, the range of Sr isotope values preserved in a single sample is similar to the range of compositions seen at the ridge segment scale. Unlike analyses of host glass compositions, which are the result of extensive crustal processing, isotopic analyses of phenocryst phases record fine-scale aggregation of these distinct mantle-derived melts and are thus an important and underutilized tool in interpreting the nature of the mid-oceanic-ridge basalts.

50. Stansell, Nathan D.; Steinman, Byron A.; Abbott, Mark B.; et al.



Lacustrine stable isotope record of precipitation changes in Nicaragua during the Little Ice Age and Medieval Climate Anomaly //GEOLOGY  Volume: 41   Issue: 2   Pages: 151-154    FEB 2013
Discerning the influences of the El Nino Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) on drought variability in the tropics during the Medieval Climate Anomaly (MCA) and Little Ice Age (LIA) will help to improve our understanding of climate system responses to internal and external forcing. Sediments from Lago El Gancho, Nicaragua, provide an similar to 1400 yr record of water balance (precipitation and evaporation) changes from a region that is sensitive to teleconnected Pacific and Atlantic ocean-atmosphere dynamics. Oxygen isotope values of ostracod carapaces (delta O-18(ostracod)) are consistently low in El Gancho sediments between ca. A.D. 950 and 1250, indicating that wetter conditions prevailed during the MCA, a period of La Nina-like mean state conditions in the tropical Pacific, and a positive mean state of the NAO. The similar to 150 yr period between the MCA and LIA was marked by an abrupt shift to persistently drier conditions at a time of highly variable Pacific sea-surface temperatures, and a transition toward a more negative NAO phase. In sediment from ca. A.D. 1450 to the present, delta O-18(ostracod) values increase, suggesting that drier conditions persisted through most of the LIA, a time of a relatively negative NAO phase and El Nino-like mean state conditions in the tropical Pacific. The long-term precipitation trends inferred from the El Gancho data are not entirely consistent with modern associations between precipitation in the circum-Caribbean region and the NAO, suggesting that present-day hydroclimatic shifts resulting from variability in synoptic climate patterns are dissimilar to changes resulting from teleconnected ocean-atmosphere dynamics that operated during the MCA and LIA.

51. Kunzmann, Marcus; Halverson, Galen P.; Sossi, Paolo A.; et al.



Zn isotope evidence for immediate resumption of primary productivity after snowball Earth //GEOLOGY  Volume: 41   Issue: 1   Pages: 27-30    JAN 2013
The Ediacaran period began with the deglaciation of the ca. 635 Ma Marinoan snowball Earth and the deposition of cap dolostones on continental shelves worldwide during post-glacial sea-level rise. These carbonates sharply overlie glacial sediments deposited at low pale-olatitudes and preserve negative carbon isotope excursions. The snowball Earth hypothesis invokes an almost complete cessation of primary productivity in the surface ocean. Because assimilatory uptake of Zn appears to fractionate its isotopes, Zn isotope ratios measured in carbonate precipitated in the surface ocean should track fluctuations in primary productivity. Here we report the first Zn isotopic data, together with carbon and oxygen isotopic profiles from a Neoproterozoic cap dolostone, the Nuccaleena Formation in the Flinders Ranges, South Australia. We interpret the Zn isotopic data in terms of a two-stage evolution of the deglacial ocean. Slightly Zn-66-enriched values at the base of the cap dolostone indicate immediate resumption of the biological pump upon melting of the surface ocean, but this signal was diluted by intense surface runoff that drove delta Zn-66 (Zn-66/Zn-64, versus the JMC Lyon reference) values down to the composition of continentally derived Zn. A subsequent rise in delta Zn-66 records a vigorous increase in primary production and export from a nutrient-laden surface ocean.

52. Virtasalo, Joonas J.; Whitehouse, Martin J.; Kotilainen, Aarno T.



Iron isotope heterogeneity in pyrite fillings of Holocene worm burrows //GEOLOGY  Volume: 41   Issue: 1   Pages: 39-JAN 2013
We present Fe-54 and Fe-56 data on pyrite from burrow-like and irregularly shaped pyrite concretions from Holocene postglacial lacustrine clays in the northern Baltic Sea collected using a secondary ion mass spectrometry (SIMS) microanalysis technique. The burrow-like concretions were formed in reducing, mucus-coated worm burrows in oxic surface sediments. Framboidal pyrite in the cores of the burrow-like concretions shows extensively fractionated delta Fe-56 values down to -3.1 parts per thousand. The framboids are cemented by poorly crystalline FeS2 with delta Fe-56 values between -2.1 parts per thousand and +1.4 parts per thousand. The irregularly shaped concretions with microcrystalline textures were formed in organic-poor sediment pore spaces, and display a wide spread of delta Fe-56 values up to +4.1 parts per thousand. The measured delta Fe-56 values reflect the preferential capture of Fe-54 to pyrite in the diagenetic sequence and the Fe-56 enrichment of remaining pore water. The diagenetic sequence of the pyrite materials is supported by previous petrographical study and S-34/S-32 microanalysis of the same samples. Our results demonstrate substantial early-diagenetic delta Fe-56 and delta S-34 heterogeneity within individual pyrite grains, underlining the necessity of high spatial resolution measurements in studying biological and abiological isotopic signatures.

53. McLoughlin, N.; Grosch, E. G.; Kilburn, M. R.; et al.



следующая страница >>