Episodic Rifting and Subsidence in the South China Sea: ERRATUM

Abstract

In Ke Ru and John D. Pigott's paper, Episodic Rifting and Subsidence in the South China (AAPG Bulletin, v. 70, no. 9, September 1986), two paragraphs on p. 1147 were scrambled. Text on p. 1147 should read as follows: occurred (Tang Xin, 1980). Because Mesozoic volcanism is absent in eastern Indochina (cf., Tang Xin, 1980), the Andean-type volcanic arc would have been located off the east coast of Indochina. We endorse Holloway's (1982) interpretation of a transcurrent fault in southwest Indochina required to offset this subduction system. Kinematically, the 20° clockwise rotation of China and Indochina, and the 45°-50° counterclockwise rotation of southwest Borneo (Hamilton, 1979) are considered by fixing mainland Asia and by placing Borneo in a position about 70° clockwise from today's position. The western edge of this arc-trench system may have formed a zone of crustal weakness, which could later be reactivated during a period of tectonic extension. However, later crustal ex ension in China is not limited to the Mesozoic accretional domain, as Cenozoic extension occurred throughout eastern and southeastern China (Tang Xin, 1980; Wang, 1982; Zhang et al, 1982; Li, 1984). Late Cretaceous The first rifting episode of the South China Sea (Figure 19B) began during the Late Cretaceous with widespread volcanic activity in southeast China, the Natuna arch, and in southwest Borneo (Tang Xin, 1980; Wang, 1982). Tectonic uplift generally characterized the entire region as documented by a regional Late Cretaceous unconformity. However, in the grabens of mainland and offshore China, thick sedimentary successions record this first episode of rifting and continental crustal extension (Wang, 1982). This rifting system trended predominantly northeast-southwest, corresponding to the general strike of the numerous and widespread normal faults on the China margin. As a consequence, the direction of extension is southeasterly. By the close of the Late Cretaceous, Borneo had started its counterclockwise rotation (Hamilton, 1979) with an approximate rotation center being offshore of the southwestern tip of present-day Borneo. Owing to the joint effect of the rotation and the southeastward extension of the continental crust to the northwest, the subduction of the preexisting oceanic crust along the Lupar line of northwestern Borneo, as evidenced by ophiolite outcrops (cf., Haile, 1973; Hutchinson, 1975; Hamilton, 1979), had begun. We infer that the major strike-slip fault southwest of Indochina End_of_Article - Last_Page 119------------