Results 81 to 90 of about 3,078 (99)

UPb geochronology of the Sri Lankan basement

Precambrian Research, 1994
Abstract UPb ages of zircons and monazites from ortho- and paragneisses representing the major crystalline basement units of Sri Lanka establish a new geochronological framework, which is consistent with previously published work on SmNd model ages, RbSr whole-rock ages, and UPb mineral ages.
S. Hölzl, A.W. Hofmann, W. Todt, H. Köhler   +3 more
openaire   +1 more source

?????????????????? (U-Pb ???? ??????????????????) ?????? ???? ???????????????????? ?????????????????? ?????????????????????? ???????????? ?? ?????????? ???????? ?????????????????????? (????????????????-???????????????? ?????????? ???????????????????????? ????????)

2014
???????????????? ???????????????????? U-Pb ???? ???????????????? ?????????????????? ??????????????????, ???? ?????????????????????????? ?? ???????????? ??. ?????????? ?? ?????????????????? ???????? ???? ?????????????????????? ????????????. ??????????????????????, ???? ???? ???????????? ???????????????????????????????? 1996 ?? 13 ?????? ????. ????????, ?
openaire   +3 more sources

Paragenesis and U-Pb systematics of baddeleyite (ZrO2)

Chemical Geology, 1993
The mineral baddeleyite (ZrO2) occurs in many terrestrial and lunar samples and some achondrite meteorites as a trace constituent that most often crystallizes in the late-stage, most chemically fractionated portions of mafic magmas together with apatite, ilmenite, ± zircon, ± zirconolite.
L.M. Heaman, A.N. LeCheminant
openaire   +1 more source

Rb–Sr and U–Pb dating of bentonites

Canadian Journal of Earth Sciences, 1983
A 6 in. (15 cm) bentonite in the Z coal (Cretaceous–Tertiary boundary) in eastern Montana was sampled at four different places, and biotite, sanidine, and zircon were separated from the clay. U–Pb analyses of purified zircons yielded small systematic variations from concordant U–Pb dates.
H. Baadsgaard, J. F. Lerbekmo
openaire   +1 more source

U-Pb ?????????????? ?????????????????????????????????? ???????????????? ???????????????????????? ?????????????? ???????????????????????????? ?????????? (???????????????????????????????????????? ???????????????? ?????????????????????? ????????)

2017
It is determined, that two-feldspar granites of the Vishnevoe massif of the Slavgorod block are the most ancient crustal granites in the Middle-Dnieper granite-greenstone terrane. Their isotopic age for monazite ??? 2985 Ma. They are close in age with enderbites of the Slavgorod complex (3014 ?? 7 Ma) and granodiorites of the Dnieper complex (2972 ?? 6
openaire   +1 more source

???????????????????? ?????????????????? ?????????? ?????????????????????? ???????? ???? ???????????? U-Pb ???????????? (3,6???3,2 ???????? ??????)

2014
???? ???????????????????? ???????? ???????????????????????????? ?????????????????????? (3,6???3,2 ???????? ??????) ?????????????????????? ???? ???????? ???????????????? ??? ?? ??????????????-?????????????????????????? ?????????????????????? ???????? ?? ????????????????-???????????????????????? ?????????????????? ??????????????????????-???????????????? ?
openaire   +1 more source

Calculation of uncertainties of U-Pb isotope data

Earth and Planetary Science Letters, 1980
Abstract Equations are derived for the estimation of errors and error correlations for various types of U-Pb isotope data, taking into account ion-beam instabilities, run-to-run variability in mass-discrimination, uncertainties in Pb and U concentrations, and uncertainties in initial-Pb and blank-Pb amount and isotopic composition. Equations are also
openaire   +1 more source

?????????????????? ??????????????????-???????????????????? ?????????????????????????? U/Pb ???????????????????????????? ????????????, ???????????????????? ???????????????????? ?? ???????????????? 1,6; 2,52 ?? 4 ??????

2016
???????????????????????? ???????????? ???????????????????? ???????????????????????? ?????????????????? ?????????????????? ?????????????????? ?? ????????-?????????????????? ???????????????????????????? ????????????, ???????????????????? ?????????????????????????????? ???????????????????? ?? ???????????????? 4 ??????. ???????????????? ????????????????????
openaire   +1 more source

U-Pb systematics in Allende inclusions

Chemical Geology, 1988
G. Manhe`s, C. Go¨pel, C.J. Alle`gre
openaire   +1 more source

U-Pb study of the Josephine Peridotite

Chemical Geology, 1988
C. Go¨pel, G. Manhe`s, C.J. Alle`gre
openaire   +1 more source