Evidence of Early Cretaceous transpression in the Sulu orogenic belt, eastern China Jun Wang a , Su-Chin Chang a, ⁎, Peijun Lin b , Xiaoqing Zhu c , Yongtao Fu d , Haichun Zhang e a Department of Earth Sciences, The University of Hong Kong, Hong Kong b Testing Center of China Metallurgical Geology Bureau of Shandong Bureau, Jinan 250014, China c Qingdao Institute of Marine Geology, Qingdao 266071, China d Key Laboratory of Marine Geology and Environment, Institute of Oceanography, Chinese Academy of Sciences, Qingdao 266071, China e State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China abstract article info Article history: Received 7 November 2015 Received in revised form 18 August 2016 Accepted 2 September 2016 Available online 4 September 2016 Recent studies have documented marine turbidites with syn-sedimentary deformation features in the central Sulu orogenic belt of eastern China. These units preserve essential information on the Late Mesozoic evolution of the Sulu orogenic belt. Referred to as the Baxiandun Formation, the turbidites exhibit similar lithologic charac- teristics to nearby units such as the Lingshandao Formation that have been well studied even though precise geo- chronologic constraints are lacking for a more precise correlation. This study reports detrital zircon U \\ Pb age data that correlate the Baxiandun Formation turbidites of the central Sulu orogenic belt to the Early Cretaceous Lingshandao Formation. We also report Al-in-hornblende emplacement depth estimates for granitic intrusions of the Sulu orogenic belt's Laoshan mountain. A sharp contact between the Laoshan granites and the marine Baxiandun Formation indicates that the Baxiandun basin rapidly subsided to the emplacement depth of the Laoshan plutons. Lateral correlation among the marine turbidites, the Lingshandao and Baxiandun Formations, combined with information established by previous studies indicates initiation of transpressional tectonics at 122–121 Ma. Transpression ceased with the emplacement of the Laoshan granites, whose A1-type composition indicates a return to extensional tectonics at ca. 111 Ma. © 2016 Elsevier B.V. All rights reserved. Keywords: Baxiandun Formation Laoshan granites Early Cretaceous U \\ Pb zircon dating Al-in-hornblende barometer Sulu orogenic belt 1. Introduction Eastern China experienced large-scale cratonic destruction during an Early Cretaceous extensional event marked by intensive volcanic ac- tivities and formations of a series of extensional continental basins (Menzies et al., 1993, 2007; Griffin et al., 1998; Xu, 2001; Carlson et al., 2005; Wu et al., 2006; Zhu et al., 2012). Recent research has shown that eastern Shandong shifted from an extensional tectonic regime to a transpressional setting during Early Cretaceous, and then changed back to extensional tectonism by the Late Cretaceous (e.g. Zhu et al., 2005; Sun et al., 2007). This hypothesis has not been thoroughly tested however, due to limited geological evidence concerning paleoenvironments and structure of the Sulu orogenic belt (SOB). Late Mesozoic marine sedimentary rocks recently have been identified in east Shandong, eastern China (e.g. Fu and Yu, 2010 Wu et al., 2010; Lu et al., 2011; Zhang et al., 2013; Sun et al., 2014), which preserve essen- tial information concerning uplift and erosion of the SOB following the final collisional episode between the North China and Yangtze blocks. Understanding these records is crucial in reconstructing Cretaceous paleogeography as it relates to interactions between the subducting Pa- cific plate and the overriding Eurasian plate. Preliminary detrital zircon geochronology (e.g. Xie et al., 2012; Wang et al., 2014) and structural observations in the field (e.g. Dong et al., 2013, 2014; Shao et al., 2014) have provided initial constraints on the evolution of late Mesozo- ic basins and established potential sedimentary provenance models. Both syn-sedimentary features (Dong et al., 2013, 2014; Wang et al., 2014) and detrital zircon age data from the recently identified Lingshandao formation (LSF) of Lingshan Island, Qingdao, east Shan- dong (Wang et al., 2014) have highlighted distinct sedimentary facies, deformation features and provenance relative to contemporaneous sed- imentary strata of the Jiaolai basin (JLB). The Lingshan Island and Baxiandun units were previously correlated to the Early Cretaceous Laiyang or Qingshan Groups of the JLB, to the north of the SOB (e.g. Bureau of Geology and Mineral Resources of Shandong, 1991; Fourth Geological and Mineral Resources Survey of Shandong, 2003). Wang et al. (2014) suggested a depositional age of ~ 121 Ma for the base of the LSF with the Yangtze block as a sedimentary source area, in contrast to that of the Laiyang Group, which was derived from the JLB. Structural features of the LSF, including syn-sedimentary deformation features such as syn-sedimentary slump folds in the inter- bedded sandstones, with hinge line direction of NE-SW and axial plane Tectonophysics 687 (2016) 44–55 ⁎ Corresponding author. E-mail address: suchin@hku.hk (S.-C. Chang). http://dx.doi.org/10.1016/j.tecto.2016.09.005 0040-1951/© 2016 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Tectonophysics journal homepage: www.elsevier.com/locate/tecto