First Evidence of the Precambrian Diamond Source of the Siberian Platform: U–Pb LA-ICP-MS Geochronological Studies of Detrital Zircon from Sedimentary Rocks of the Moti Group

Abstract

The U–Pb LA-ICP-MS age is analyzed for detrital zircons from diamondiferous sandstones of the Khuzhir Formation of the Moti Group of a sedimentary cover of the south Siberian Platform. Similar ages are determined for two samples with the most representative maxima at 620, 780, 1860, and 2550 Ma and single data within the ranges of 985–1000, 1400–1500, 1150–1190, 2700–2880, and 3225–3230 Ma. The maximum age of sedimentation is 605 ± 6 Ma, which corresponds to the Ediacaran and is close to a period of carbonatite and alkali-silicate magmatism of the region. The Neoproterozoic ages correspond to the age of rocks of the Tuva–Mongolian Terrane of the Central Asian Orogenic Belt, and the most ancient maxima are typical of the basement rock complexes of the south Siberian Platform. Our result allows the first substantiation of the Precambrian age of diamondiferous sedimentary rocks of the Khuzhir Formation and therefore indicates the presence of Precambrian diamondiferous rocks within the Siberian Platform.