Leonid Neymark
Leonid Neymark is a Scientist Emeritus with the Geology, Geophysics, and Geochemistry Science Center.
I am currently a Scientist Emeritus in the Geology, Geophysics, and Geochemistry Science Center after being transferred from the Geochemistry Team, Yucca Mountain Project Branch where I conducted U-series studies of soils, fracture minerals and water-rock interaction processes.
I conduct a wide spectrum of isotope-geochemical studies involving radiogenic isotopes of U, Pb, Sr, and Nd and using ICP-MS and TIMS techniques. Before 2010 I was a principal investigator and a member of the Geochemistry Team in the Yucca Mountain Project Branch, WRD. The team's task was to evaluate geochemical aspects of the hydrogeologic suitability of Yucca Mountain to permanently store high-level radioactive waste. My focus was on the history of secondary mineral deposition (largely calcite and silica) in soil and unsaturated- and saturated-zone settings and on isotope-geochemical indicators of water-rock interaction as evidence of past water flow. These studies used U-Pb and U-series and other isotope-geochemical methods to characterize the timing of low-temperature surface processes of mineral deposition and to evaluate past water-rock interaction. In 2004 I was closely involved in the installation and detailed testing of a new ThermoFinnigan thermal-ionization mass-spectrometer Triton. I developed reproducible mass-spectrometric methods of U-series isotope measurements for whole rock samples with large Th/U and 232Th/230Th ratios. Previous YMPB work included systematic characterization of subsurface and soil hydrogenic minerals to provide a basis for understanding past hydrologic and climate variability in the Yucca Mountain region.
Current Projects
- Sources of Pb contamination in domestic well water in SW Missouri
- Matrix Pore Waters - Ultracentrifugation Method for Low-Permeability Sedimentary and Crystalline Rocks
- The U-Th-Pb whole-rock isotope system in the Chalk River core and past redox conditions
- Impact of Exhalative Hydrothermal Systems on Marine Chemistry: Applications for Mineral Assessment
- Conditions and Processes Affecting Radionuclide Transport (writing a chapter for the GSA Memoir devoted to Yucca Mountain, volume 2
Professional Experience
Research Chemist, Geology, Geophysics, and Geochemistry Science Center, USGS
Principal investigator and member of the Geochemistry Team in the Yucca Mountain Project Branch, USGS
2001-2004. S.M. Stoller Corporation, Senior Geochemist
1996-2001. Pacific Western Technologies, Ltd. Senior Scientist
1993-1996. US Geological Survey Visiting Research Scientist
1985-1993. Institute of Precambrian Geology and Geochronology (IPGG), St. Petersburg, Russian Academy of Sciences
1971-1985. All Union Geological Research Institute, Leningrad (USSR Ministry of Geology). Engineer (1971-1981) and Junior Research Scientist (1981-1985)
Education and Certifications
Ph.D. in Geochemistry, St. Petersburg, Russia
MS degree in Radiochemistry, St. Petersburg, Russia
Affiliations and Memberships*
American Geophysical Union
Geological Society of America
International Geochemistry Association
Geochemical Society
Science and Products
Precise determination of δ88Sr in rocks, minerals, and waters by double-spike TIMS: A powerful tool in the study of chemical, geologic, hydrologic and biologic processes
Evaluation of Pleistocene groundwater flow through fractured tuffs using a U-series disequilibrium approach, Pahute Mesa, Nevada, USA
U–Pb, Rb–Sr, and U-series isotope geochemistry of rocks and fracture minerals from the Chalk River Laboratories site, Grenville Province, Ontario, Canada
234U/238U and δ87Sr in peat as tracers of paleosalinity in the Sacramento-San Joaquin Delta of California, USA
Ion-probe U–Pb dating of authigenic and detrital opal from Neogene-Quaternary alluvium
Conditions and processes affecting radionuclide transport
Direct U-Pb dating of Cretaceous and Paleocene dinosaur bones, San Juan Basin, New Mexico: COMMENT
Potential effects of alpha-recoil on uranium-series dating of calcrete
Limited hydrologic response to Pleistocene climate change in deep vadose zones - Yucca Mountain, Nevada
Modern U-Pb chronometry of meteorites: advancing to higher time resolution reveals new problems
Lead isotopes and trace metals in dust at Yucca Mountain
Thermal history of the unsaturated zone at Yucca Mountain, Nevada, USA
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
- Science
- Data
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Filter Total Items: 64
Precise determination of δ88Sr in rocks, minerals, and waters by double-spike TIMS: A powerful tool in the study of chemical, geologic, hydrologic and biologic processes
We present strontium isotopic (88Sr/86Sr and 87Sr/86Sr) results obtained by 87Sr–84Sr double spike thermal ionization mass-spectrometry (DS-TIMS) for several standards as well as natural water samples and mineral samples of abiogenic and biogenic origin. The detailed data reduction algorithm and a user-friendly Sr-specific stand-alone computer program used for the spike calibration and the data reAuthorsLeonid A. Neymark, Wayne R. Premo, Nikolay N. Mel'nikov, Poul EmsboEvaluation of Pleistocene groundwater flow through fractured tuffs using a U-series disequilibrium approach, Pahute Mesa, Nevada, USA
Groundwater flow through fractured felsic tuffs and lavas at the Nevada National Security Site represents the most likely mechanism for transport of radionuclides away from underground nuclear tests at Pahute Mesa. To help evaluate fracture flow and matrix–water exchange, we have determined U-series isotopic compositions on more than 40 drill core samples from 5 boreholes that represent discreteAuthorsJames B. Paces, Paul J. Nichols, Leonid A. Neymark, Harihar RajaramU–Pb, Rb–Sr, and U-series isotope geochemistry of rocks and fracture minerals from the Chalk River Laboratories site, Grenville Province, Ontario, Canada
As part of the Geologic Waste Management Facility feasibility study, Atomic Energy of Canada Ltd. (AECL) is evaluating the suitability of the Chalk River Laboratories (CRL) site in Ontario, situated in crystalline rock of the southwestern Grenville Province, for the possible development of an underground repository for low- and intermediate-level nuclear waste. This paper presents petrographic andAuthorsLeonid A. Neymark, Zell E. Peterman, Richard J. Moscati, R. H. Thivierge234U/238U and δ87Sr in peat as tracers of paleosalinity in the Sacramento-San Joaquin Delta of California, USA
The purpose of this study was to determine the history of paleosalinity over the past 6000+ years in the Sacramento-San Joaquin Delta (the Delta), which is the innermost part of the San Francisco Estuary. We used a combination of Sr and U concentrations, d87Sr values, and 234U/238U activity ratios (AR) in peat as proxies for tracking paleosalinity. Peat cores were collected in marshes on Browns IsAuthorsJudith Z. Drexler, James B. Paces, Charles N. Alpers, Lisamarie Windham-Myers, Leonid A. Neymark, Thomas D. Bullen, Howard E. TaylorIon-probe U–Pb dating of authigenic and detrital opal from Neogene-Quaternary alluvium
Knowing depositional ages of alluvial fans is essential for many tectonic, paleoclimatic, and geomorphic studies in arid environments. The use of U–Pb dating on secondary silica to establish the age of Neogene-Quaternary clastic sediments was tested on samples of authigenic and detrital opal and chalcedony from depths of ∼25 to 53 m in boreholes at Midway Valley, Nevada. Dating of authigenic opalAuthorsLeonid A. Neymark, James B. PacesConditions and processes affecting radionuclide transport
Characteristics of host rocks, secondary minerals, and fluids would affect the transport of radionuclides from a previously proposed repository at Yucca Mountain, Nevada. Minerals in the Yucca Mountain tuffs that are important for retarding radionuclides include clinoptilolite and mordenite (zeolites), clay minerals, and iron and manganese oxides and hydroxides. Water compositions along flow pathsAuthorsArdyth M. Simmons, Leonid A. NeymarkDirect U-Pb dating of Cretaceous and Paleocene dinosaur bones, San Juan Basin, New Mexico: COMMENT
Based on U-Pb dating of two dinosaur bones from the San Juan Basin of New Mexico (United States), Fassett et al. (2011) claim to provide the first successful direct dating of fossil bones and to establish the presence of Paleocene dinosaurs. Fassett et al. ignore previously published work that directly questions their stratigraphic interpretations (Lucas et al., 2009), and fail to provide sufficieAuthorsAlan E. Koenig, Spencer G. Lucas, Leonid A. Neymark, Andrew B. Heckert, Robert M. Sullivan, Steven E. Jasinski, Denver W. FowlerPotential effects of alpha-recoil on uranium-series dating of calcrete
Evaluation of paleosol ages in the vicinity of Yucca Mountain, Nevada, at the time the site of a proposed high-level nuclear waste repository, is important for fault-displacement hazard assessment. Uranium-series isotope data were obtained for surface and subsurface calcrete samples from trenches and boreholes in Midway Valley, Nevada, adjacent to Yucca Mountain. 230Th/U ages of 33 surface samplesAuthorsL.A. NeymarkLimited hydrologic response to Pleistocene climate change in deep vadose zones - Yucca Mountain, Nevada
Understanding the movement of water through thick vadose zones, especially on time scales encompassing long-term climate change, is increasingly important as societies utilize semi-arid environments for both water resources and sites viewed as favorable for long-term disposal or storage of hazardous waste. Hydrologic responses to Pleistocene climate change within a deep vadose zone in the easternAuthorsJ.B. Paces, L.A. Neymark, J. F. Whelan, J. L. Wooden, S.P. Lund, B.D. MarshallModern U-Pb chronometry of meteorites: advancing to higher time resolution reveals new problems
In this paper, we evaluate the factors that influence the accuracy of lead (Pb)-isotopic ages of meteorites, and may possibly be responsible for inconsistencies between Pb-isotopic and extinct nuclide timescales of the early Solar System: instrumental mass fractionation and other possible analytical sources of error, presence of more than one component of non-radiogenic Pb, migration of ancient raAuthorsY. Amelin, J. Connelly, R. E. Zartman, J.-H. Chen, C. Gopel, L.A. NeymarkLead isotopes and trace metals in dust at Yucca Mountain
Lead (Pb)-isotope compositions and trace-metal concentrations were determined for samples of dust collected from underground and surface locations at and near the proposed radioactive waste repository at Yucca Mountain, Nevada. Rare earth element concentrations in the dust samples from the underground tunnels are similar to those in wholerock samples of the repository host rocks (Miocene Tiva CanyAuthorsLoretta Kwak, Leonid A. Neymark, Zell E. PetermanThermal history of the unsaturated zone at Yucca Mountain, Nevada, USA
Secondary calcite, silica and minor amounts of fluorite deposited in fractures and cavities record the chemistry, temperatures, and timing of past fluid movement in the unsaturated zone at Yucca Mountain, Nevada, the proposed site of a high-level radioactive waste repository. The distribution and geochemistry of these deposits are consistent with low-temperature precipitation from meteoric watersAuthorsJ. F. Whelan, L.A. Neymark, R.J. Moscati, B.D. Marshall, E. RoedderNon-USGS Publications**
Yu.V. Amelin and L.A. Neymark. 1998, Lead isotope geochemistry of Paleoproterozoic layered intrusions in the eastern Baltic Shield: Inferences about magma sources and U-Th-Pb fractionation in the crust-mantle system. Geochim. Cosmochim. Acta., vol. 62, no. 3, 493-505, https://doi.org/10.1016/S0016-7037(98)00056-8.E.Yu. Rytsk, L.A. Neimark, Yu.V. Amelin, 1998, Paleozoic granitoids in the Northern Part of the Baikal Orogenic Area: Age and Past Geodynamic Settings. Geotectonics, vol. 32, no. 5, 379-393.L.A. Neymark, E.Yu. Ritsk, B.M. Gorokhovskiy. 1996. Pb isotope characteristics of some late Riphean Pb-Zn deposits in the folded environs of the Siberian platform. Transactions of the Russian Academy of Sciences. vol.342, no.4, p. 183-187.L.A. Neimark, A.M. Larin, G.V. Ovchinnikova et al., 1996, U-Pb geochronologic and Pb-isotopic evidence for the Mesozoic mineralization stage of the Archean Stanovoi Megablock, Aldan-Stanovoi Shield. Petrology, vol. 4, no.4, 421-435.V.A. Vernikovsky, L.A. Neymark, V.A. Ponomarchuk, and S.Z. Yakovleva, 1996, New U-Pb, Sm-Nd, Rb-Sr, and K-Ar ages for the North Taymyr collisional granites and metamorphites: Transactions of the Russian Academy of Sciences. vol. 345a, no.9, 329-334.R.A. Kumpulainen, J. Mansfeld, K. Sundblad, L. Neymark, and T. Bergman, 1996, Stratigraphy, Age, and Sm-Nd Isotope Systematics of the country rocks to Zn-Pb Sulfide Deposits, Ammeberg District, Sweden: Economic Geology, vol. 91, 1009-1021, https://doi.org/10.2113/gsecongeo.91.6.1009.L.A. Neimark, E.Yu. Ritsk, G.V. Ovchinnikova et al. 1995. Lead isotopes in gold deposits of the Eastern Sayan (Russia). Geology of Ore Deposits. vol. 37, no. 3, 201-212.E.V. Khain, L.A. Neymark, Y.V. Amelin, 1995, Isotope-geochronological study of the granites and granite-gneisses of the Gargan Block, Eastern Sayan Range, Siberia, by Pb-Pb and U-Pb method on zircons and Sm-Nd method, Doklady of the Russian Academy of Sciences, vol. 342, no. 5, 776-779 (in Russian).L.A. Neimark, E.Y. Ritsk, B.M. Gorokhovsky, V.F. Guseva, S.Z. Yakovleva, 1995, Age of Muya granites, Baikal-Vitim ophiolite belt (U-Pb and Sm-Nd isotopic evidence), Doklady of the Russian Academy of Sciences, vol. 343, no. 5, 673-676 (in Russian).V.A.Vernikovskii, L.A. Neimark, V.A. Ponomarchuk et al. 1995. Geochemistry and age of collision granitoides and metamorphites of the Kara microcontinent (Northern Taimyr). Russian Geology and Geophysics. vol. 36, no.4, 46-60.V.A. Vernikovsky, A.E. Vernikovskaya, S.M. Lyapunov, L.A. Neimark, V.F. Proskurin, A.I. Chernykh, I.Yu. Safonova, 1994, Petrology, geochemistry, and tectonic setting of plagiogranites of the Chelyuskin ophiolite belt: International Geology Review, vol. 36, no. 10, 961-974.L.A. Neymark, Yu.V. Amelin, A.M. Larin. 1994. Pb-Sr-Nd isotopic and geochemical constraints on the origin of the 1.54-1.56 Ga Salmi rapakivi-granite -- anorthosite batholith (Karelia, Russia). Mineral. Petrol., vol. 50, no.1-3, 173-193, https://doi.org/10.1007/BF01160146.S.A. Alekseenko, S.L. Ivlev, and L.A. Neimark, 1994, Standard reference sample of lead isotopic composition: Journal of Analytical Chemistry, vol. 49, no. 12, 1154-1158.L.A. Neymark, A.A. Nemchin, V.R. Vetrin, E.B. Sal'nikova. 1993. Sm-Nd and Pb-Pb isotope systematics in the lower crust xenoliths from the diatremas in the Southern Kola Peninsula. Transactions of the Russian Academy of Sciences. vol.329, no. 6, 781-784.I.M. Gorokhov, M.S. Dufour, L.A. Neymark et al. 1993, Early Paleozoic Gondwana fragments in the nappes of the Central Pamirs and Lesser Himalayas: geochemical and isotopic characteristics. Stratigraphy and Geologic Correlation. vol.1, no.3, 250-263.G.V. Ovchinnikova, L.A. Neymark, O.A. Levchenkov et al. 1993. On the use of the apatite as an U-Pb geochronometer. Stratigraphy and Geological Correlation. vol.1, no.1, 9-19.L.A. Neymark, E.Yu. Ritsk, N.G. Rizvanova. 1993. Hercynian age and Precambrian crustal protolith of the Barguzin granitoides of the Angar-Vitim batholith : U-Pb and Sm-Nd isotope evidence. Transactions of the Russian Academy of Sciences, vol.332, no.7, 201-206.L.A. Neymark, V.P. Kovach, A.A. Nemchin et al. 1993. Late Archean intrusive complexes in the Olekma granite-greenstone terrain (Eastern Siberia): geochemical and isotopic study. Prec. Res. vol.62, no.2, 453-472, https://doi.org/10.1016/0301-9268(93)90016-U.L.A. Neymark, E.Yu. Ritsk, N.G. Rizvanova, B.M. Gorokhovsky. 1993. U-Pb zircon age evidence for a polichronous Angaro-Vitim batholith. Transactions of the Russian Academy of Sciences. vol.333, no.5, 634-637.V.A. Vernikovsky, L.A. Neymark, V.F. Proskurin, S.Z. Yakovleva. 1993. Late-Riphean age of the Kunar massif plagiogranites (U-Pb zircon dating). Transactions of the Russian Academy of Sciences. vol. 331, no. 6, 706-708.L.A. Neymark, E.Yu. Ritsk, B.M. Gorokhovsky, Yu.V. Amelin, G.V. Ovchinnikova. 1993. Geochronological and isotope-geochemical study of the gold ore deposits in the Baikal fold area. In: Isotope Dating of Ore Deposits. Moscow, Nauka, p. 124-146 (in Russian).L.A. Neymark, A.M. Larin, E.Yu. Ritsk, G.V. Ovchinnikova, B.M. Gorokhovsky. 1993. U-Pb geochronological and Pb-isotope evidence of the Hercynian ore-forming event within the Proterozoic frame of the South Siberian Platform. Transactions of the Russian Academy of Sciences. vol.333, no.6, 765-768.L.A. Neymark, A.M. Larin, G.V. Ovchinnikova, and S.Z. Yakovleva. 1992. U-Pb age of the Dzhugdzhur anorthosites. Transactions of the Russian Academy of Sciences. vol.323A, no.3, 57-62.L.A. Neymark, A.M. Larin, S.Z.Yakovleva, B.M. Gorokhovsky. 1992. U-Pb age of igneous rocks of the Ulkan graben in the Southeastern part of the Aldan Shield. Transactions of the Russian Academy of Sciences. v.324, no.4, 92-96.L.A. Neymark, A.A. Nemchin, O.M. Rozen, V.P. Serenko, V.P. Spetsius, I.K. Shuleshko. 1992. Sm-Nd isotope systematics in the lower crust xenoliths from kimberlites of Yakutia. Transactions of the Russian Academy of Sciences. vol.327, no.3, 88-93.L.A. Neymark, A.M.Larin, S.Z. Yakovleva, N.A. Sryvtsev, and V.V. Buldygerov. 1991. New U-Pb zircon age data on the Akitkan suite, Baikal-Patom fold area. Transactions of the USSR Academy of Sciences. vol. 321, n.8, 197-201.A.M. Larin, Yu.V.Amelin, and L.A.Neymark. 1991, Age and genesis of the complex scarn ores of the Pitkaranta ore district associated with the Salmi rapakivi massif (Southern Karelia). Geologia Rudnykh Mestorozhdenij (Geology of Ore Deposits), vol. 6, 15-33 (in Russian).L.A. Neymark, E.Yu. Ritzk, B.M. Gorokhovsky et al., 1991, Lead isotopic composition and genesis of the Pb-Zn mineralization of the Olokit zone of the Northern Baikal region. Geologia Rudnykh Mestorozhdenij (Geology of Ore Deposits), vol. 6, 34-49 (in Russian).L.K. Levsky and L.A. Neymark. 1991, Isotopic constraints on a prototerrestrial matter. In: The Early Crust : its composition and age. Moscow, Nauka, p. 48-63 (in Russian).Yu. Amelin, A. Beljaev, A. Larin, L. Neymark, I. Stepanov, 1991. Rapakivi granites and related rocks symposium, July 29-31, 1991, Helsinki, Finland; Salmi batholith and Pitkaranta ore field in Soviet Karelia excursion, August 1-4, 1991 Haapala, Ilmari; Ramo, O Tapani; Salonsaari, Pekka T; GCP, International Geological Correlation Programme Opas - Geologian Tutkimuskeskus, vol.33, 57 pp.S.A. Sergeyev, Ye.V. Bibikova, O.A. Levchenkov, S.B. Lobach-Zhuchenko, S.Z. Yakovleva, G.V. Ovchinnikova, L. A. Neymark, A.N. Komarov, B.M. Gorokhovskiy, 1990. Isotope geochronology of the Vodlozerskiy gneiss complex, Geokhimiya, vol.1990, no.1, 73-83. (in Russian).G.V. Ovchinnikova, S.B. Lobach-Zhuchenko, S.A. Sergeyev, S.Z. Yakovleva, O.A. Levchenkov, L.A. Neymark, A.N. Komarov, B.M. Gorokhovskiy, A.M. Fedoseyenko, I.N. Krylov, 1990. Geochronology and petrology of the late kinematic granites of southeastern Karelia based on geochemical and isotopic data. Geokhimiya, vol.1990, no.11, 1561-1573 (in Russian).V.L. Dook, L.A. Neymark, and V.A. Rudnik (Eds.). 1989. The Oldest Rocks of the Aldan-Stanovik Shield, Eastern Siberia, USSR. IGCP Project 280 “The Oldest Rocks on Earth”, Excursion guide, Leningrad-Mainz, 121 p.Yu.V. Amelin, L.A. Neymark, D.I. Matukov et al. 1988. Analytical parameters and operation experience of MI1320-PRM2 mass-spectrometers . In: Isotopic methods in geology, geochemistry and metallogeny. Leningrad, Nauka, p.102-116. (in Russian).L.A. Neymark, G.V. Ovchinnikova, B.M. Gorokhovsky et al. 1988. Pb isotopes in sulfides from rocks of the Sumozero--Kenozero greenstone belt. In: Isotopic methods in geology, geochemistry and metallogeny. Leningrad, Nauka. p. 42-48. (in Russian).L.A. Neymark, A.B. Kotov, D.P. Vinogradov et al. 1988. Age and occurrence of early folded and post-folded granitoids of northwestern Lake Ladoga region according to data of Pb, O isotopes. In: Isotopic methods in geology, geochemistry and metallogeny. Leningrad, Nauka p. 21-41. (in Russian).L.A. Neymark, S.L. Mirkina, A.G. Rublev et al. 1987. Isotope age of the granites in the Irelsky Complex, Baikal Region. Izvestiya Akademii Nauk SSSR. vol. 5, 18-25 (in Russian).A.G. Rublev, G.A. Murina, A.P. Chukhonin, L.A. Neimark, et al. 1987. Geochronology of early-Proterozoic granitoid magmatism in the Kodar-Udokan Zone. Soviet Geology and Geophysics, vol. 28, no.6, 26-33, 1987 (in Russian).L.A. Neymark. 1987. Potential and restrictions of the lead-isochron method in dating Precambrian polymetamorphic rocks. In: Isotopic dating of metamorphic and metasomatic process. Shukoljukov Yu.A. (Ed.). Moscow, Nauka, p. 29-44 (in Russian).L.A Neymark. 1987. The application of U-Pb to the geochronological studies of Precambrian metallic ore deposits. In: Gorokhov I.M., Levchenkov O.A. (Editors) Isotopic methods on Geochronology. Leningrad, Nauka, p.29-44 (in Russian).L.A. Neymark. 1986 U-Pb isotopic constraints on the age and primordial materials of the Earth. In: Isotope methods in geochemistry and cosmochemistry. L.K.Levsky (Ed.) Leningrad, Nauka, p. 3-21 (in Russian).L.A. Neymark, A.D. Iskanderova, E.P. Miron'uk et al. 1984. U-Pb age of the Charskoje ore deposit of BIF, Eastern Siberia. Doklady Akademii Nauk SSSR. vol. 234. 1246-1249. (in Russian).L.A. Neymark. 1983. Quantitative models for the evolution of the crust-mantle system utilizing Pb isotope data. In: Geochemistry of radiogenic isotopes in the early stages of the Earth's evolution. Shukol’ukov J.A. (Ed.), Moscow, Nauka, p.151-167 (in Russian).G.V. Ovchinnikova, L.A. Neymark. 1981. The excess lead in meteorites. Geochemistry International. vol.18, no.4, 102-115.L.A. Neymark, A.D. Iskanderova, A.P. Chukhonin, et al. 1981. U-Pb data on the Archean age of metamorphic rocks of the Stanovoy Range: Geochemistry International, vol.18, no.5, 55-64.L.A. Neymark, O.A. Levchenkov. 1979. A method of age calculation for open U-Pb isotope systems. Geochemistry International. vol.16, no.3, 34-39.S.L. Mirkina, L.A.Neymark, B.B. Golubev, I.G. Smyslova. 1976. Radiologic dating of Neogene-Quaternary uranium minerals by Pb-isotope method. Geokhimia, no. 9, 43-48 (in Russian).**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government