Isotope composition (5¹³C, S¹⁸O) of Lower Permian carbonates of Permian Pre-Kama and products of its hypergenic alteration

Abstract

Carbon and oxygen isotope composition of Lower Permian carbonates is similar to carbonates of the Perm Zechstein basin and Sakmarian-and-Kazanian dolomites of the east side of Russian platform. Local variations of 513С and 518О in the Kungurian dolomites are caused by its formation in basin with various hydrodynamic activity and depth. Solikamsk carbonates formed in basin with different evaporating rate in fringe and central zones. Difference of isotope structure of the Kungurian carbonates from the Solikamsk ones is caused by change of the regressive regimen of the early Perm basin to transgressive regimen that is caused by water basin demineralization. Hypergenesis of Lower Permian dolomites in the condition of semiarid climate and repeated infiltrations of atmospheric waters lead to formation of two product groups. The first is presented by secondary cavernous dolomite enriched by13C, and the second - reworked (neogenic) calcite enriched by12C and16O which filled interstices in secondary dolomite.

Keywords

• литология
• карбонаты
• эвапориты
• изотопия углерода и кислорода
• гипергенез