The Paleoproterozoic Kolvitsa Anorthosite Massif: New Data on the U–Pb Age (ID TIMS) and Geochemical Features of Zircon

The Paleoproterozoic Kandalaksha-Kolvitsa Gabbro-Anorthosite Complex (Fennoscandian Shield): New U–Pb, Sm–Nd, and Nd–Sr (ID-TIMS) Isotope Data on the Age of Formation, Metamorphism, and Geochemical Features of Zircon (LA-ICP-MS)

“…The estimated U-Pb age (2448 ± 5 Ma) of metagabbro from the Kolvitsa massif is considered magmatic due to low contents of U and Pb typical of magmatic zircons from basic rocks and spectra of REE distribution. The obtained U-Pb age is interpreted as the time of gabbro formation in the Kolvitsa massif [13] and is close to previously calculated ages of anorthosites from this massif [7,8].…”

“…The determination limits were in the range of 0.01 ppm when the diameter of the laser beam was 155 µm, which was in compliance with the available data [17][18][19]. The results were verified in interlaboratory cross-checks and analyses of internationally approved standard zircon samples 91500, TEMORA 1, and Mud Tank [11][12][13].…”

“…External calibration was carried out using NIST 612 glass with the known contents of REE, U, and Th of 40 ppm as a multipoint calibration forced through the origin after blank correction. The diameter of the laser beam was changed, while all of the rest parameters remained the same: From 35 µm to 240 µm (r = 0.999) [11][12][13]. Sample NIST SRM 610 with the content of 450 ppm was used to check the accuracy of data reduction [14][15][16].…”

Baddeleyite from Large Complex Deposits: Significance for Archean-Paleozoic Plume Processes in the Arctic Region (NE Fennoscandian Shield) Based on U-Pb (ID-TIMS) and LA-ICP-MS Data

“…Studying and applying Zr-Ti geochronometer for baddeleyite is considered important. New investigations yield higher temperatures of the baddeleyite grains formation and the U-Pb systematics closure (more than 10,000˚C), compared to zircon (less than 9000˚C) [20] [21] [22]. These newly obtained high temperatures of the U-Pb systematics closure and baddeleyite formation are close to other geochronometers, e.g.…”

“…[21] [22]. The NIST SRM 610 and NIST SRM 612[23] [24] [25] glasses are silicate glass reference materials produced by the National Institute of Standards and Technology.…”