Based on a new method of paleomagnetic data analysis, a reconstruction of the Kaapvaal, Karelian, Pilbara, and Superia cratons in the Neoarchean was tested. The most likely positions of these cratons within the Kenorland supercontinent, which existed in the Neoarchean, have been proposed. New paleomagnetic data obtained on the basis of the Neoarchean complexes allowed the motion of cratons to be calculated at 4–9 cm per year. The paleomagnetic reconstruction is in good agreement with the structural-geological peculiarities of the coeval complexes.

Giant quartz veins are widespread on the Bundelkhand Craton of the Indian Shield which precise ages with a SHRIMP-II, U-Th-Pb isotope are quantified in this article. Their relative geological age is well-documented: they cut the Paleoproterozoic (2150–1800 Ma) sediments of the Bijawar Group and are overlain by Proterozoic (1670–1030 Ma) sediments at the base of the Upper Vindhyan Supergroup. U-Th-Pb dating of zircon grains from a quartz vein was carried out to assess major event of their formation as 1866 ± 12 Ma. This data is consistent with the relative geological age of the veins. In addition, the quartz veins were shown to contain 2.86, 2.7, and 2.54 Ga xenocrystic zircon grains. Rocks with these ages are abundant in the craton. The formation of a giant quartz vein swarm is associated with the deformation of the Bundelkhand Craton lithosphere during 1.9–1.8 Ga ago triggered by compression caused by collision processes at the western flank of the Columbia Supercontinent on one side and plume activity on the other.

ГЕОЛОГИЧЕСКАЯ КАРТА ЮГО-ВОСТОЧНОЙ ФЕННОСКАНДИИ МАСШТАБА 1:750 000: НОВЫЕ ПОДХОДЫ К СОСТАВЛЕНИЮ

The paper presents results of the first geochronologic study (LA-ICP-MS zircon method) of metasedimentary rocks that host the banded iron formation (BIF) and the metarhyolites (halleflinta) of the Gimoly Group in the Kostimuksha greenstone belt,Karelian Craton. Felsic magmatism that produced the rhyolite sills and dikes was dated at 2759 ± 19–2743 ± 15 Ma. The clearly predominant group of zircons in the schists (metagraywacke) has an isotope age of 2753 ±19 Ma, and scarce zircon grains of these rocks vary in age from 3.1 to 2.8 Ga. Geochemically, zircons from metarhyolites fall into three types (1) Eu-depleted and Ce-enriched, (2) Eu- and Ce-enriched, and (3) LREE- and MREE-enriched. The zircons of geochemical types (1) and (2) are also predominant in the sediments. The morphology and structure of zircon crystals in the rhyolites and sediments are also identical. The rhyolites were thus a major source of zircons for the metagraywacke, which alternates with BIF, while the Mesoarchean rocks played a subordinate role. The BIF of the Gimoly Group in the Kostomuksha Greenstone Belt was formed simultaneously with felsic volcanism at 2760–2740 Ma.