PALEOARCHEAN MAFIC ROCKS OF THE SOUTHWESTERN SIBERIAN CRATON: PRELIMINARY GEOCHRONOLOGY AND GEOCHEMICAL CHARACTERIZATION

A V Ivanov,V I Levitsky,I V Levitsky,E I Demonterova,L Z Reznitsky

doi:10.5800/gt-2017-8-3-0267

Abstract

The Siberian craton consists of Archean blocks, which were welded up into the same large unit by ca 1.9 Ga [Gladkochub et al., 2006; Rojas-Agramonte et al., 2011]. The history of the constituent Archean blocks is mosaic because of limited number of outcrops, insufficient sampling coverage because of their location in remote regions and deep forest and difficulties with analytical studies of ancient rocks, which commonly underwent metamorphic modifications and secondary alterations. In this short note, we report data on discovery of unusual for Archean mafic rocks of ultimate fresh appearance. These rocks were discovered within southwestern Siberian craton in a region near a boundary between Kitoy granulites of the Sharyzhalgai highgrade metamorphic complex and Onot green-schist belt (Fig. 1). Here we present preliminary data on geochronology of these rocks and provide their geochemical characterization.

Highlights

The Siberian craton consists of Archean blocks, which were welded up into the same large unit by ca 1.9 Ga [Gladkochub et al, 2006; Rojas-Agramonte et al, 2011]
The youngest among the measured ages corresponds to a peak of granite magmatism and metamorphism in the southern Siberian Craton [Rojas-Agramonte et al, 2011]
The oldest of the measured ages is older than any published ages for the Sharyzhalgai high-grade metamorphic complex [Turkina et al, 2012] and approaching the oldest published age of 3386±14 Ma for plagiogneisses of the Onot green-schist belt [Bibikova et al, 2006]

Summary

Introduction

The Siberian craton consists of Archean blocks, which were welded up into the same large unit by ca 1.9 Ga [Gladkochub et al, 2006; Rojas-Agramonte et al, 2011]. The history of the constituent Archean blocks is mosaic because of limited number of outcrops, insufficient sampling coverage because of their location in remote regions and deep forest and difficulties with analytical studies of ancient rocks, which commonly underwent metamorphic modifications and secondary alterations. In this short note, we report data on discovery of unusual for Archean mafic rocks of ultimate fresh appearance. We report data on discovery of unusual for Archean mafic rocks of ultimate fresh appearance These rocks were discovered within southwestern Siberian craton in a region near a boundary between Kitoy granulites of the Sharyzhalgai highgrade metamorphic complex and Onot green-schist belt (Fig. 1). We present preliminary data on geochronology of these rocks and provide their geochemical characterization

Methods

Results

Discussion

Conclusion