Acta Geochim (2018) 37(2):257–280 https://doi.org/10.1007/s11631-017-0211-1 ORIGINAL ARTICLE Constraints on sedimentary ages of the Chuanlinggou Formation in the Ming Tombs, Beijing, North China Craton: LA-ICP-MS and SHRIMP U–Pb dating of detrital zircons 1,2 1 1,3 4 Jing Ding • Yuruo Shi • Alfred Kro¨ner • J. Lawford Anderson Received: 13 November 2016 / Revised: 10 February 2017 / Accepted: 16 August 2017 / Published online: 1 September 2017 Ó Science Press, Institute of Geochemistry, CAS and Springer-Verlag GmbH Germany 2017 Abstract Detrital zircons in five sedimentary samples, the Chuanlinggou Formation in the Ming Tombs District MC1 to MC5, from the bottom of the Chuanlinggou For- was deposited in a low-energy mud flat sedimentary mation in the Ming Tombs District, Beijing, were dated environment in the inter-supra tidal zone because it is with the LA-ICP-MS and SHRIMP U–Pb methods. Age mainly composed of silty mudstone and fine-grained spectra of the five samples show a major peak at 2500 Ma sandstone with relatively simple sedimentary structures. and a secondary peak at 2000 Ma, suggesting their provenances were mainly from the crystalline basement of Keywords Detrital zircon Á LA-ICP-MS U–Pb ages Á the North China Craton and the Trans-North China Orogen. SHRIMP Á Chuanlinggou Formation Á Ancient sedimentary The youngest zircon has an age of 1673 ± 44 Ma, indi- environment Á North China Craton cating that the Chuanlinggou Formation was deposited after this age. From sample MC4 to MC5, lithology changed from a clastic rock (fine-grained sandstone) to a 1 Introduction carbonate rock (fine-grained dolomite), suggesting that the depositional basin became progressively deeper. The age Zircon has stable physical and chemical properties, being spectrum of sample MC5 shows a major peak at 2500 Ma rich in U and Th, with low Pb and a low ion diffusion rate. and a secondary peak at 2000 Ma. Sample MC4, which is The zircon U–Pb isotopic system is ideally suited for U–Pb stratigraphically lower than sample MC5, only had one dating and generally records the time of zircon crystal- peak at 2500 Ma. We conclude that there was a trans- lization because of a high closure temperature for the U–Pb gressive event when sediments represented by MC5 was isotopic system and is minimally affected by later thermal deposited, and seawater carried ca. 2000 Ma clastic mate- events when compared with other isotopic systems (Lee rials to the basin where the Chuanlinggou Formation was et al. 1997; Cherniak et al. 1997; Cherniak and Watson deposited, leading to the addition of ca. 2000 Ma detritus. 2001; Poitrasson et al. 2002; Corfu et al. 2003). Our research indicates that the source area for the sedi- Clastic components in sedimentary rocks are products of ments became more extensive with time. We conclude that weathering, denudation, transportation, and sedimentation of rocks from their source region. Detrital zircons are resistant to weathering and abrasion, and they preserve an & Yuruo Shi age record of their original host rocks. Therefore, detrital [email protected] zircon chronology is a potentially powerful tool to con- 1 Beijing SHRIMP Center, Institute of Geology, Chinese strain sedimentary provenance, leading to a better under- Academy of Geological Sciences, Beijing 100037, China standing of the source area, the regional palaeogeography, 2 China University of Geosciences, Beijing 100083, China the depositional age, and the tectonic relationship between 3 Institut fu¨r Geowissenschaften, Universita¨t Mainz, different crustal terranes supplying detritus (Krogh et al. 55099 Mainz, Germany 1990; Sircombe and Freeman 1999; Yao et al. 2011; 4 Department of Earth and Environment, Boston University, Cawood and Nemchin 1999; Kositcin and Krapezˇ 2004; Boston, MA 02215, USA Wan et al. 2011; Hu et al. 2009, 2013). 123 258 Acta Geochim (2018) 37(2):257–280 The North China Craton (NCC), which is located north occurred in the interior and along the margins of the NCC. of the Qinling-Dabie Orogenic Belt and south of the In the north, such rifting formed the Yanliao aulacogen Central Asian Orogenic Belt, is the largest craton in eastern which reaches into the central region of the craton in a NE- Asia and one of the oldest cratons on Earth. The NCC SW direction. The thickness of the aulacogen is largest at experienced multi-stage cratonization processes and even- Jixian, China (its depocenter within the aulacogen) and tually formed a stable craton in the Late Neoarchean becomes thinner towards the margin. The Ming Tombs (Cheng 1994; Bai et al. 1993; Zhao 1993; Shen et al. 1992; area is located in the middle of the aulacogen and its Lu et al. 1996; Li et al. 2000; Zhai 2011; Wan et al. 2015). sedimentary fill include Meso-Neoproterozoic strata which Vertically, the NCC has a typical double-layer structure rest unconformably on Archean gneisses. Of these, the consisting of an older crystalline basement and younger strata of the Mesoproterozoic Changcheng Group consist of sedimentary cover deposited unconformably after 1.8 Ga the Changzhougou, Chuanlinggou, Tuanshanzi, and (Li et al. 2006). The Changcheng Group, the first sedi- Dahongyu Formations, in ascending order. mentary cover, is considered the beginning of the Meso- Samples MC1 to MC5, in ascending order, were col- proterozoic in the regional stratigraphic chart in China. The lected from the Chuanlinggou Formation in the Ming boundary age between the Paleoproterozoic and the Tombs District, Beijing (Fig. 2). The Chuanlinggou For- Mesoproterozoic is ca. 1800 Ma in China (All China mation is in conformable contact with the underlying Commission of Stratigraphy 2001), but 1600 Ma in the Changzhougou Formation (Hebei Bureau of Geology and International Geological Time Scale. Thus, many Mineral Resources 1982). Sample MC1 was collected researchers have studied the depositional time of the 44 cm above the contact between the Changzhougou and Changcheng Group (Wan et al. 2003, 2011; Li et al. Chuanlinggou formations, with alatitude and longitude of 2011, 2013a, b; Gao et al. 2008, 2009; Peng et al. 2012; N40°17056.800,E116°10055.800; the lithology is a silty Zhang et al. 2013). Past studies on the depositional time of mudstone, composed of 75% clay minerals, 15% quartz, the Chuanlinggou Formation of the Changcheng Group 7% mica and 3% feldspar (Fig. 3). Siltstone sample MC2 is included dating of intrusives (Gao et al. 2009; Zhang et al. composed of quartz (70%), feldspar (20%), and mica 2013), detrital minerals (Wan et al. 2011; Zhang et al. (10%). Sample MC3 is composed of laminated siltstone 2015; Duan et al. 2014), interbedded volcanic tuffs (Sun and fine-grained sandstone with unequal thickness between et al. 2013) and authigenic minerals (Zhang et al. 2015). 0.05 and 0.5 mm. Sample MC4 is a fine-grained sandstone However, the deposition time of the Chuanlinggou For- with siliceous cement and a grain-supported structure and mation and its sedimentary environment are still its clastic components are mainly quartz (about 90%). controversial. Sample MC5 is a fine-grained dolomite, composed of 90% This paper reports LA-ICP-MS and SHRIMP U–Pb data dolomite, 6% quartz, 2% calcite and 2% feldspar, with derived from detrital zircons of five sedimentary samples particle sizes of most grains about 0.08 mm and is fairly that were collected from the bottom of the Chuanlinggou well sorted. Formation of the Changcheng Group in the Ming Tombs area and Beijing. These data provide new evidence for study of the sedimentary age, provenance of the Chuan- 3 Analytical techniques linggou Formation, and the Precambrian geological evo- lution of the NCC. The sediment samples were crushed mechanically and heavy mineral concentrates were prepared using standard heavy liquid and magnetic separation techniques. Zircons 2 Geological setting and sample description were extracted from the heavy mineral concentrate by hand-picking under a binocular microscope, mounted in The Precambrian units of the NCC consist of the Archean- epoxy, and polished to expose the cores of individual Paleoproterozoic crystalline basement and the overlying grains. The grain mount was then photographed in reflected Meso-Neoproterozoic sedimentary strata (Fig. 1). Consol- light, cleaned, and gold-coated. Cathodoluminescence (CL) idation of the basement marks the end of the Paleopro- imaging was done using a scanning electron microscope terozoic Era and deposition of the cover marks the (HITACHI S3000-N) fitted with a GATAN Chroma at the beginning of the Mesoproterozoic Era. The Lu¨liang Beijing SHRIMP Center, Institute of Geology, Chinese Movement (1900–1800 Ma) has been considered the ulti- Academy of Geological Sciences. mate consolidation of the NCC basement. Afterwards, the The LA-ICP-MS analytical work was performed at the stabilized NCC entered a platform phase, which is also the Institute of Mineral Resources, Chinese Academy of named stage of the development and evolution of a rift Geological Sciences, Beijing. The laser ablation system system (Zhai et al. 2014). This is because such rifting analyses were conducted on a Newwave UP213 and the 123 Acta Geochim (2018) 37(2):257–280 259 Fig. 1 Distribution of Archean-Paleoproterozoic crystalline basement and Meso-Neoproterozoic cover in the North China Craton. Modified from Peng et al. (2011) ICP-MS analyses were done on a Bruker M90 model. The age spectra for detrital zircons and calculation of weighted laser ablation spot diameter was 25 lm, the output fre- mean ages were performed using the Isoplot program quency was 10 Hz and energy densities were about 2.5 J/ (Ludwig 2003). Errors for single data points are at the 1r cm2. Helium gas was used as a carrier gas and Ar was used level. as a compensation gas to adjust sensitivity.