Early Miocene magmatism in the Baiyun Sag (South China Sea): A view to the origin of intense post-rift magmatism

Seismically Imaged Crustal Breakup in the Southwest Taiwan Basin of the Northeastern South China Sea Margin

“…(2016)), the Baiyun Sag (modified after Sun et al. (2022)), and the Southern Depression (modified after Lester et al. (2014)), which exhibit the widths of the hyper‐extended crust and the thicknesses of the thinnest crust.…”

“…The major failed rifts were found in these basins, such as the Changchang Sag in the QDNB (Gao et al., 2016; Lei & Ren, 2016; C. M. Zhang et al., 2013), the Baiyun and Liwan Sags in the PRMB (Deng et al., 2018; Hu et al., 2009; Sun et al., 2022; J. H. Wang et al., 2018; Zhao et al., 2019), and the Southern Depression in the SWTB (Lester et al., 2014; McIntosh et al., 2014; Yeh et al., 2012). The thinnest crusts in the Changchang Sag and Baiyun Sag are ∼0.8 km thick (∼0.25 s two‐way travel time (TWTT), Gao et al., 2016) and ∼3.3 km thick (∼1 s TWTT, Sun et al., 2022), correlating to the widths of their hyper‐extended (i.e., less than 10 km thick) zones, ∼80 km, and ∼50 km, respectively (Figures 1b and 1c). However, previous studies (Lester et al., 2014; McIntosh et al., 2014) revealed an ∼100 km wide hyper‐extended domain in the Southern Depression of the SWTB where the thinnest crust is ∼4 km thick (Figure 1d).…”

“…The northern continental margin of the SCS hosts several highly rifted basins (Figure 1a), for example, the Qiongdongnan Basin (QDNB), the Pearl River Mouth Basin (PRMB), and the Southwest Taiwan Basin (SWTB) that aligning from west to east. The major failed rifts were found in these basins, such as the Changchang Sag in the QDNB (Gao et al., 2016; Lei & Ren, 2016; C. M. Zhang et al., 2013), the Baiyun and Liwan Sags in the PRMB (Deng et al., 2018; Hu et al., 2009; Sun et al., 2022; J. H. Wang et al., 2018; Zhao et al., 2019), and the Southern Depression in the SWTB (Lester et al., 2014; McIntosh et al., 2014; Yeh et al., 2012). The thinnest crusts in the Changchang Sag and Baiyun Sag are ∼0.8 km thick (∼0.25 s two‐way travel time (TWTT), Gao et al., 2016) and ∼3.3 km thick (∼1 s TWTT, Sun et al., 2022), correlating to the widths of their hyper‐extended (i.e., less than 10 km thick) zones, ∼80 km, and ∼50 km, respectively (Figures 1b and 1c).…”

“…The red dashed box denotes the location of the study area. (b-d) Two-dimensional multi-channel seismic profiles of the Changchang Sag (modified after Gao et al (2016)), the Baiyun Sag (modified after Sun et al (2022)), and the Southern Depression (modified after Lester et al (2014)), which exhibit the widths of the hyper-extended crust and the thicknesses of the thinnest crust. SWTB, Southwest Taiwan Basin; PRMB, Pearl River Mouth Basin; QDNB, Qiongdongnan Basin; CCS, Changchang Sag; BYS, Baiyun Sag; LWS, Liwan Sag; SD, Southern Depression.…”

“…the Southwest Taiwan Basin (SWTB) that aligning from west to east. The major failed rifts were found in these basins, such as the Changchang Sag in the QDNB (Gao et al, 2016;Lei & Ren, 2016; C. M. Zhang et al, 2013), the Baiyun and Liwan Sags in the PRMB (Deng et al, 2018;Hu et al, 2009;Sun et al, 2022;J. H. Wang et al, 2018;Zhao et al, 2019), and the Southern Depression in the SWTB (Lester et al, 2014;McIntosh et al, 2014;Yeh et al, 2012).…”