Late Archean: Mesoproterozoic geology of the Tarim craton

Abstract

Chronological studies show that the Late Archean petrographic formation of the Tarim craton includes Tuogelakbulak complex in the northern margin and the Milan Group in the northern slope of the eastern Altun Mountains. The Tuogelakbulak complex is mainly plagioclase amphibolite, hornblende schist, gray gneiss, garnet biotite schist, actinolite mica quartz schist, biotite quartz schist, and migmatite, mixed with minor amount of marble lenticular bodies, and intruded by gneissic muscovite biotite granite. The Milan Group is composed of various types of felsic gneiss, granulite, marble, and plagioclase amphibolite, and belongs to hypometamorphic supracrustal rock series. The Neoarchean is an important episode of continental crust growth and basement cratonization of the Tarim craton, and a continental crust with the age of about 3.6 Ga might have existed in the Tarim craton basement. The Lower Proterozoic of the Tarim craton is extensively distributed and outcropped at Quruqtagh in the northern margin, Altun Mountains in the eastern margin and Yecheng area in the southwestern margin. Protoliths of the Paleoproterozoic Xingditag Group and Altun Mountains Group are mainly clastic sedimentary rock, carbonate rock, and volcanic formations, indicating a relatively stable and extensive littoral-neritic sedimentary environment. They are mainly composed of a suite of intermediate and high grade metamorphic rocks, including biotite plagioclase gneiss, muscovite biotite plagioclase gneiss, quartz schist, marble, and garnet sillimanite plagioclase quartz gneiss, resembling khondalite series. Magmatism was not significant during this episode, though the Paleoproterozoic magmatic rocks are observed in Altun Dunhuang, Tiekelike and Korla areas. During the Mesoproterozoic episode, the Tarim craton was relatively stable. The Jixianian Aierjigan Group is characterized by carbonate and clastic rock series formed in epicontinental sea. Magmatic formation consists of the Changchengian Sailajiazitage Group and the Jixianian Ailiankate Group formed in intracontinental extension setting.