Results 271 to 280 of about 166,341 (292)

U-Pb AGE OF THE CHATTANOOGA SHALE

Geological Society of America Bulletin, 1960
An attempt was made to date the upper black unit of the Gassaway member of the Chattanooga shale which carries the maximum U/Pb ratio. Three samples were analyzed by isotopic dilution techniques. The U238-Pb206 ages on all 3 samples agreed within their experimental errors. The average of the two samples with reasonably small errors gave an apparent age
J. C. COBB, J. L. KULP
openaire   +1 more source

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

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

U-Pb Ages from the Neoproterozoic Doushantuo Formation, China

Science, 2005
U-Pb zircon dates from volcanic ash beds within the Doushantuo Formation (China) indicate that its deposition occurred between 635 and 551 million years ago. The base records termination of the global-scale Marinoan glaciation and is coeval with similar dated rocks from Namibia, indicating synchronous deglaciation.
Daniel, Condon, Maoyan, Zhu, Samuel, Bowring, Wei, Wang, Aihua, Yang, Yugan, Jin   +5 more
openaire   +2 more sources

Interpretation of discordant U‐Pb zircon ages: An evaluation

Journal of Metamorphic Geology, 1997
The most widely used technique for the determination of high precision mineral growth ages in igneous and metamorphic rocks is dating of zircons with the U‐Pb method. The interpretation of these ages, particularly in metamorphic settings, is hampered by an incomplete understanding of the common phenomenon of partial Pb‐loss in zircon.
Mezger, Klaus, KROGSTAD, E. J.
openaire   +1 more source

U-Pb-возраст гранитов Хаутаваарской структуры (Карелия)

2019
The results of U-Pb isotopic dating of Hautavaara structure granites located in Vedlozero - Segozersky greenstone belt show that the Shuya and the Hautavaara complexes, as well as the Nyalmozero massif were formed synchronously 2,74-2,73 billion years ago.
openaire   +1 more source

Air abrasion experiments in U-Pb dating of zircon

Chemical Geology, 1986
Abstract Air abrasion of zircon grains can remove metamict material that has lost radiogenic Pb and zircon overgrowths that were added during younger events and thereby improve the precision of the age measurements and permit closer estimates of the original age.
S.S. Goldich, Lynn B. Fischer
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

?????????????????? ??????????????????-???????????????????? ?????????????????????????? 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