The chemical composition and age of monazite and kularite from titanium ore of Pizhemskoye and Yarega deposits (Middle and Southern Timan)

Abstract

A study on the typomorphic characteristics and age of the monazite the two giant titanium deposits of the Timan – Pizhemskoye and Yarega, which revealed differences in morphology in the species composition of the inclusions, the grain size, distribution of chemical types of a mineral associated with conditions of crystallization and different sources of the substance. The isochronous Th-Pb monazite age was calculated using the «CHIME» method. For Yarega monazite built three isochrone with age 1301, 1105 and 778 Ma; for Pizhemsky monazite-kularite one isochrone with age 782 Ma. Source of hith-Th monazite Yarega oil-titanium deposit could be ancient granite batholith and the origin Yarega less-Th monazite and Nd-Ce-monazite-kularite Pizhemskoye deposit with an age of ~ 780 Ma could be related to the hydrothermal conversion of the weathering crusts on lamprophyres close in age with lamprophyre (spessartite and kersantite) of Chetlassky Kamen.

Authigenic rhabdophane from brown iron ore of the oxidation zone of the Babaryk massive sulfide occurrence (South Urals): scanning electron microscope (SEM) and electron backscattered diffraction (EBSD) study

“…Several structural patterns of hexagonal rhabdophane from the Inorganic Crystal Structure Database (ICSD) and monoclinic monazite from the American Mineralogist Crystal Structure Database (AMCSD) were used as the comparison phases. The data on the orientation of the individual crystals in rhabdophane aggregates are shown as Euler color schemes, pole figures and orientation distribution density heatmaps (Mason and Schuh, 2009).…”

“…Unfortunately, the lack of data on the space group of tristramite prevents the EBSD-based identification of this mineral. It should be noted that "kularite" (a variety of monazite) also contains Ca but by an order of magnitude less than in rhabdophane (Makeev et al, 2020).…”

“…In addition to simple anhydrous phosphates, florensite is also found in postdiagenetic Al-rich sedimentary rocks (Rasmussen et al, 1998). In the weathering crust of black shales and gold placers, a specific type of impurityrich monazite (kularite) was found as spherical particles with inclusions of rock-forming minerals (Makeev et al, 2020). Rhabdophane, a hexagonal hydrous REE phosphate, mainly occurs in late hydrothermal associations of alkaline rocks (syenites, carbonatites) and polymetallic veins associated with granites (http://www.mindat.org, last access: 1 October 2021).…”

Unique titanium Deposits of Timan: genesis and age issues

“…There are no zoning, quartz and carbonate veins, large segregations and crystals of ore minerals and inability of titanium transfer by hydrothermal fluid is considered a premature solution. One of the latest models suggests that the Yarega sandstones are of Neoproterozoic age, and the source of the ore material was lamprophyres for titanium phases and granites for zircon and other rare and rare earth minerals [22].…”

“…Age of the Yarega deposit was erroneously taken as Middle Devonian, since the Middle Devonian pollen was found in the ore. Later it was found that the Late Devonian pollen was also present. After the formation of titaniferous sandstones of the Yarega deposit, oil migrating into them, having its own Permian-Jurassic age [21], brought the Middle-Late Devonian flora (spores and pollen) of the Devonian plants [22]. Sandy-argillaceous titaniferous rocks of the Pizhemskoye deposit do not contain leading biota.…”