Paleozoic to Early Mesozoic Tectonics of North China Craton

Abstract

The North China Craton (NCC) started its Paleozoic evolution from ca. 520 Ma when Gondwana assembled in its peak tectonism. The Middle Cambrian developed in margins of the NCC on older strata or basement rocks. Then the marine environment expansion and its extensive invasion led to the late Middle Cambrian marine deposits, the Mantou Formation and afterwards occurred throughout the NCC. New results of the Bainaimiao arc belt, north to the northern NCC indicated that the arc was active from 520 Ma and lasted to 420 Ma, which could extend to east Siping in NE China. Along the southern edge of the NCC the northward subduction of the Shangdan Ocean was operated during ca. 514–420 Ma. Marine regression occurred postdated the Majiagou phase in Middle Ordovician in most parts of the NCC. Recently in the northern NCC some Devonian plutons and volcanic rocks were recognized. The Late Carboniferous sedimentary sequence with the ‘G’ layer of bauxites at its bottom is overlain disconformably upon the Middle Ordovician limestone. The bauxites were derived mainly from ashes produced by volcanism mainly in the Inner Mongolia Paleo-uplift (IMPU) during Paleozoic period, particularly in latest Early Carboniferous to Early Permian when the northern margin of the NCC evolved as an Andean-style active continental margin. The sequence is mainly clastic formations, composed of coal-bearing sandstones and siltstones interlayered with marine limestone and volcanic ash, which demonstrates that they formed in terrestrial–marine transitional or terrestrial environment with volcanic arc settings. After late Early Permian a terrestrial environment was dominant in the NCC. In the southern NCC and the Qinling Orogenic Belt (QOB) spreading of the Mianlue Ocean between the South China Craton (SCC) and South Qinling Block (SQB) was sustained in Late Paleozoic and the northward subduction–accretion of the Mianlue Ocean was active in Late Paleozoic. In Triassic, the collision between the SCC and SQB along the Mianlue suture resulted in intense shortening and uplift of QOB and HP/UHP metamorphism documented in Hong’an-Dabie-Sulu terranes. Meanwhile in the northern NCC, significant changes in tectonic deformation and magmatism occurred in Late Triassic. In the Panshan region, the northern NCC, intensive regional folding and thrusting took place around 210 Ma, which shows that the NCC underwent into its initial decratonization.