Leonid Neymark (Former Employee)
Science and Products
Filter Total Items: 65
Uranium–Lead dating, opal Uranium–Lead dating, opal
No abstract available.
Authors
Leonid A. Neymark
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 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...
Authors
Leonid A. Neymark, Wayne R. Premo, Nikolay N. Mel’nikov, Poul Emsbo
Evaluation of Pleistocene groundwater flow through fractured tuffs using a U-series disequilibrium approach, Pahute Mesa, Nevada, USA Evaluation 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...
Authors
James B. Paces, Paul J. Nichols, Leonid A. Neymark, Harihar Rajaram
U–Pb, Rb–Sr, and U-series isotope geochemistry of rocks and fracture minerals from the Chalk River Laboratories site, Grenville Province, Ontario, Canada U–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...
Authors
Leonid A. Neymark, Zell E. Peterman, Richard J. Moscati, R. H. Thivierge
234U/238U and δ87Sr in peat as tracers of paleosalinity in the Sacramento-San Joaquin Delta of California, USA 234U/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...
Authors
Judith Z. Drexler, James B. Paces, Charles N. Alpers, Lisamarie Windham-Myers, Leonid A. Neymark, Thomas D. Bullen, Howard E. Taylor
Ion-probe U–Pb dating of authigenic and detrital opal from Neogene-Quaternary alluvium Ion-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...
Authors
Leonid A. Neymark, James B. Paces
Conditions and processes affecting radionuclide transport Conditions 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...
Authors
Ardyth M. Simmons, Leonid A. Neymark
Direct U-Pb dating of Cretaceous and Paleocene dinosaur bones, San Juan Basin, New Mexico: COMMENT Direct 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...
Authors
Alan E. Koenig, Spencer G. Lucas, Leonid A. Neymark, Andrew B. Heckert, Robert M. Sullivan, Steven E. Jasinski, Denver W. Fowler
Potential effects of alpha-recoil on uranium-series dating of calcrete Potential 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...
Authors
L.A. Neymark
Limited hydrologic response to Pleistocene climate change in deep vadose zones - Yucca Mountain, Nevada Limited 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...
Authors
J.B. Paces, L.A. Neymark, J. F. Whelan, J. L. Wooden, S.P. Lund, B.D. Marshall
Modern U-Pb chronometry of meteorites: advancing to higher time resolution reveals new problems Modern 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...
Authors
Y. Amelin, J. Connelly, R. E. Zartman, J.-H. Chen, C. Gopel, L.A. Neymark
Lead isotopes and trace metals in dust at Yucca Mountain Lead 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...
Authors
Loretta Kwak, Leonid A. Neymark, Zell E. Peterman
Non-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.
Science and Products
Filter Total Items: 65
Uranium–Lead dating, opal Uranium–Lead dating, opal
No abstract available.
Authors
Leonid A. Neymark
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 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...
Authors
Leonid A. Neymark, Wayne R. Premo, Nikolay N. Mel’nikov, Poul Emsbo
Evaluation of Pleistocene groundwater flow through fractured tuffs using a U-series disequilibrium approach, Pahute Mesa, Nevada, USA Evaluation 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...
Authors
James B. Paces, Paul J. Nichols, Leonid A. Neymark, Harihar Rajaram
U–Pb, Rb–Sr, and U-series isotope geochemistry of rocks and fracture minerals from the Chalk River Laboratories site, Grenville Province, Ontario, Canada U–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...
Authors
Leonid A. Neymark, Zell E. Peterman, Richard J. Moscati, R. H. Thivierge
234U/238U and δ87Sr in peat as tracers of paleosalinity in the Sacramento-San Joaquin Delta of California, USA 234U/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...
Authors
Judith Z. Drexler, James B. Paces, Charles N. Alpers, Lisamarie Windham-Myers, Leonid A. Neymark, Thomas D. Bullen, Howard E. Taylor
Ion-probe U–Pb dating of authigenic and detrital opal from Neogene-Quaternary alluvium Ion-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...
Authors
Leonid A. Neymark, James B. Paces
Conditions and processes affecting radionuclide transport Conditions 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...
Authors
Ardyth M. Simmons, Leonid A. Neymark
Direct U-Pb dating of Cretaceous and Paleocene dinosaur bones, San Juan Basin, New Mexico: COMMENT Direct 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...
Authors
Alan E. Koenig, Spencer G. Lucas, Leonid A. Neymark, Andrew B. Heckert, Robert M. Sullivan, Steven E. Jasinski, Denver W. Fowler
Potential effects of alpha-recoil on uranium-series dating of calcrete Potential 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...
Authors
L.A. Neymark
Limited hydrologic response to Pleistocene climate change in deep vadose zones - Yucca Mountain, Nevada Limited 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...
Authors
J.B. Paces, L.A. Neymark, J. F. Whelan, J. L. Wooden, S.P. Lund, B.D. Marshall
Modern U-Pb chronometry of meteorites: advancing to higher time resolution reveals new problems Modern 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...
Authors
Y. Amelin, J. Connelly, R. E. Zartman, J.-H. Chen, C. Gopel, L.A. Neymark
Lead isotopes and trace metals in dust at Yucca Mountain Lead 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...
Authors
Loretta Kwak, Leonid A. Neymark, Zell E. Peterman
Non-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).
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