International Geology Review, Vol. 47, 2005, p. 270–296. Copyright © 2005 by V. H. Winston & Son, Inc. All rights reserved. 0020-6814/05/790/270-27 $25.00 270 Late Paleozoic Sedimentation on the Northern Margin of the North China Block: Implications for Regional Tectonics and Climate Change TIM COPE, 1 Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305 BRADLEY D. RITTS, Department of Geology, Utah State University, Logan, Utah 84322-4505 BRIAN J. DARBY , Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803 ANDREA FILDANI, AND S. A. GRAHAM Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305 Abstract The Late Paleozoic collision between the North China continental block and the Altaid arc terranes of Mongolia represents one of the earliest and most fundamental tectonic events in the ongoing construction of Asia. New detrital zircon provenance data from Carboniferous–Permian nonmarine strata on the northern margin of North China imply that the northern margin of the North China block constituted a continental margin arc prior to this collision (~400–275 Ma) and that collision took place via south-directed subduction beneath North China. A significant and widespread climate change took place in North China in mid-Permian time, and is recorded by a change from Carboniferous and Lower Permian humid-climate, coal-bearing sedimentary facies to Upper Permian and Lower Triassic arid-climate redbeds. In northern North China, this climate change is accompanied by a paleocurrent reversal, which indicates the onset of uplift on the northern margin of the North China block. The temporal association of climate change and uplift suggests that aridification of North China may have been caused by a rainshadow effect from topography related to the convergence and ultimate collision between the North China block and the Altaid arc terranes of Mongolia. Alternatively, climate change may have occurred as a result of northward drift of the North China block through arid subtropical latitudes. Introduction THE ASIAN CONTINENT comprises a number of oce- anic and continental fragments that were assembled in Phanerozoic time by a succession of continental collisions (Molnar and Tapponnier, 1975; Zhang et al., 1984; Wang and Mo, 1995; Sengör and Natal’in, 1996; Yin and Nie, 1996). One of the most funda- mental collisional belts related to this assembly is the Suolon suture (Wang and Mo, 1995), the site of late Paleozoic collision between the combined North China–Tarim block and Paleozoic arc terranes of Mongolia, which represents the closure of a sig- nificant ocean basin and the beginning of amalgam- ation between major blocks of China and those of Siberia (Fig. 1). Although this ocean basin closure clearly was a major event in the ongoing construc- tion of Asia, little is known in detail about the timing, the nature of the colliding blocks, the exact location of the suture zone, or the effects of the col- lision in North China. The pre-collisional northern margin of the North China block, for example, has been described variously as a passive margin subducting northward beneath successively accret- ing arc terranes or a continental arc/accretionary complex (cf. Hsu et al., 1991; Robinson et al., 1999; Wang and Liu, 1986). Additionally, although most workers agree that ocean basin closure along the Suolon suture was completed by Late Permian– 1 Corresponding author; present address: Department of Geol- ogy and Geography, DePauw University, Greencastle, IN 46135; present email: tcope@depauw.edu