Biosis: Biological Systems (2020) 1(2): 72-84 https://doi.org/10.37819/biosis.001.02.0054 ORIGINAL RESEARCH Large Scale Dinoturbation in Braided Stream Deposits: Evidence from the Cretaceous Tugulu Group of the Hami Area, Eastern Xinjiang, China Lida Xinga,b * , Martin G. Lockleyc **, Zhongdong Lid, Hendrik Kleine, Shaojie Chenf, W. Scott Persons IVg, Miaoyan Wangb a State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, China b School of the Earth Sciences and Resources, China University of Geosciences, Beijing, China c Dinosaur Trackers Research Group, University of Colorado Denver, PO Box 173364, Denver, CO 80217, USA d Geophysical Team of Sichuan Bureau of Geological and Mineral Investigation and Exploration, Chengdu 610072, China e Saurierwelt Paläontologisches Museum Alte Richt 7, D-92318 Neumarkt, Germany f The First Team of Hydrogeology and Engineering Geology, Xinjiang Bureau of Geo- Exploration & Mineral Development, Urumqi 830091, China g Mace Brown Museum of Natural History, Department of Geology and Environmental Geosciences, College of Charleston, Charleston 29401, USA *Corresponding author: Lida Xing: [email protected] ** Martin G. Lockley: [email protected] © The Author(s) 2020 ABSTRACT Large dinosaur tracks were recently reported from locations in the ARTICLE HISTORY Pterosaur-Yadan National Geological Park situated about 100 km south of Received 23 April 2020 Hami in Xinjiang Province, China. The park comprises a substantial area in a much larger arid region comprising and an extensive spectrum of Revised 31 May 2020 Cretaceous, siliciclastic, Tugulu Group, lithofacies representing proximal, Accepted 8 June 2020 basin margin, alluvial fan and braided stream deposits, grading into alluvial plain, deltaic and lacustrine facies near the depocenter. Due to the difficulties of conducting detailed geological surveys in such a vast and KEYWORDS inhospitable area, definitive resolution of the litho-, bio- and chrono- Sauropod tracks stratigraphy is challenging in some areas, and yet to be published in detail. Braided stream deposits Nevertheless, the occurrence of large dinosaur tracks and dinoturbated Pterosaur-Yadan National units, here interpreted as sauropodan, in association with root casts, Geological Park dinosaur bone and fossil wood, points to the potential of this frontier area to yield valuable paleontological information, and show that flora and fauna were found in arid braided stream systems away from the lacustrine depocenters where body fossils are more abundant and better known. Introduction Jurassic-Cretaceous has been studied in some detail. As noted by Wang et al. (2019) Xinjiang Province is a vast semi-arid area at the heart of the Asian continent. It has a complex “Basin type and evolution are closely geological history, representing several major associated with the regional tectonic setting cycles of basin development from Jurassic to (Hendrix et al., 1992). During the Latest Recent, with some localities better known than Triassic, Late Jurassic, Late Cretaceous, and others. However, the regional geology of the Late Cenozoic, the basins were mainly 72 Xing et al., 2020 Biosis: Biological Systems (2020) 1(2): 72-84 foreland basins associated with the the Tian Shan Mountains in Xinjiang, reactivation of the Tian Shan [Mountains ... northwestern China (See Gu et al. (2003) for with] Late Jurassic–Early Cretaceous lithofacies descriptions). Wang et al. (2014; 2017) reactivation related to the far-field effect of described hundreds of skeletons and eggs from accretion between Lhasa Block and south the pterosaur Hamipterus from the Tugulu Group Asian …uplift and denudation of the Tian of Turpan-Hami Basin. In September 2018, The Shan was accompanied by the flexural First Team of Hydrogeology and Engineering subsidence of the nearby crust, sediment Geology, Xinjiang Bureau of Geo-Exploration & filling, and formation of sedimentary basins Mineral Development and the Geophysical Team within and adjacent to the Tian Shan of Sichuan Bureau of Geological and Mineral range …including the Junggar, Tarim, Investigation and Exploration, discovered Turupan, and Yili basins. The southern dinosaur tracks in the Shennvfeng (Goddess Peak) Junggar and northern Tarim basins are area (GPS: 42° 43ʹ10.23” N, 92° 37ʹ50.39” E) of separated by the Tian Shan, while the Pterosaur-Yadan National Geological Park, in Turupan and Yili basins are intermontane Hami, Xinjiang province. The Shennvfeng basins” (p. 3). location is 667 km southeast of the Wuerhe tracksite, and ~100 km west of Hami city (Fig. 1). As noted by Li et al. (2014), “during the Late The main authors (LX and ML) examined this Jurassic, collision of the Lhasa and Qiangtang track site in November 2019 and documented a blocks (…) a major change in climate from semi- batch of dinosaur natural track casts. humid and semi-arid to arid condition took place, and reddish strata of the Upper Jurassic were Institutional abbreviations developed across the Junggar Basin (p. 145)”. They show (Li et al. 2014: fig. 11) the SNF, Shennvfeng tracksite, Hami, Xinjiang desertification of the region due to the cutting off Uygur Autonomous Region, China of monsoon rains by the uplift of the Tian Shan Mountains. This resulted in the deposition of Local Geological setting coarse grained depositional systems “with rare fossils only developed locally in the Junggar The Pterosaur-Yadan National Geological Park is Basin due to lack of continuous rainfall and situated in the northern margin of Lop Nur discharge.” (Li et al. 2014). (Luobupo), about 100 km west of Hami and 20 km from Wubao Town. It is about 400 km long The Lower Cretaceous Tugulu Group of the from east to west and 20 km wide from south to Junggar Basin was formed under fluviolacustrine north. Dinosaur tracks were found in the lower conditions (Wang et al., 2014). In Xinjiang, the part of Shennvfeng (= The Goddess Peak) in the group has yielded many important vertebrate east of the geopark. Our observations of the fossils, including the Early Cretaceous sedimentary facies in the study area is consistent Dsungaripterus-Psittacosaurus fauna (Dong, with the general suite of lithofacies described by 2001). There are also abundant records of Gu et al. (2003) for the Junggar basin from tetrapod tracks known from the Tugulu Group. alluvial fans, braided streams alluvial plain to However, the record is concentrated in the delta and lake from basin margin to depocenter. Wuerhe area, Kelamayi, in the southern margin of More specifically the description of the typical the Junggar Basin. There are two main tracksites braided streams deposits as consisting of gravelly in Wuerhe. The Huangyangquan site is one of sandstone and moderately fine sandstone is them, and includes bird-dominated, non-avian consistent with the lithofacies in the study area. dinosaur (stegosaur, theropod), pterosaur and turtle footprint assemblages (Xing et al., 2011; The sedimentary facies in the study area consist 2013a; 2014; He et al., 2013). Dinosaur, bird and of medium-thick bedded poorly sorted, coarse to pterosaur footprints are also known from the very coarse, cross bedded fluvial sandstones with Lower Cretaceous asphaltite site (Xing et al., local pebble-filled channels. The coarser 2013b). The degree of correspondence between sandstones and conglomerates contain angular rip body fossils and tracks (Lockley, 1991; Lockley up clasts of finer sandstone, large disarticulated et al., 1994) makes Wuerhe a Type 2b deposit, dinosaur bone fragments and fossil wood (Figs. where the fossil track record dominates and bone 2–4). There are local water escape structures, and evidence is inconsistent with the track fauna. rare root casts. Locally one may observe tabular flat topped units of fine sand, some of which have The Lower Cretaceous Tugulu Group is also been trampled or “dinoturbated” (sensu Lockley, exposed in local basins within the greater Junggar 1991) by large trackmakers. Basin, such as the Turpan-Hami Basin, south of 73 Biosis: Biological Systems (2020) 1(2): 72-84 Xing et al., 2020 Fig. 1. Locality map of north central Xinjiang showing the Shennvfeng site ~100 km west of Hami. Fig. 2. Stratigraphic section showing position of track-bearing levels in the Tugulu Group at the Shennvfeng site. Based on original data from the geological report of the Paleocene Taizicun Formation (1–7 layers) by the Xinjiang Institution Geological Survey (2003). The discovery of vertebrate fossils and dinosaur footprints indicates that this area should belong to Cretaceous sediments. 74 Xing et al., 2020 Biosis: Biological Systems (2020) 1(2): 72-84 Fig. 3. A: large vertebra, and B: long bone embedded in sand containing large rip up clasts. C: narrow vertical root casts. D: water escape structure. Scale in A 1.0 m, scales in B–D 15 cm. Fig. 4. A: The sedimentary facies at the Shennvfeng track site IV show a 70 cm thick pink siltstone (double-ended vertical arrow), abruptly cut by pebble conglomerates (downward facing arrow). Black lines indicate channel margins. The local stratigraphic sequences consist of coarse and very coarse poorly sorted cross-bedded fluvial sandstone with granule (2–4 mm) and pebble (4–64 mm) components especially in channel fills. B: A similar pink silty unit cut by a pebble filled channel: compare with A. According to the Xinjiang East Tianshan 1: the Paleocene Taizicun Formation–the Eocene 250000 geological map and regional geological Bakaner Formation (Xinjiang Institution survey report (Wupu unit, No. K46C002002), the Geological Survey, 2003). However, the presence strata of the Shennvfeng tracksite area belongs to of pterosaur fossils demonstrates that the strata 75 Biosis: Biological Systems (2020) 1(2): 72-84 Xing et al., 2020 originally attributed to the Paleocene Taizicun Hutubihe Fm: deltaic, shore-shallow lake, Formation instead belongs to the Cretaceous Shengjinkou Fm: deltaic, Lianmuqin Fm: deltaic, Tugulu Group, shown as lying unconformably on shore-shallow lake (Gu et al., 2003). In the Late Jurassic sediments throughout the region (Li northwestern margin of the basin, the Tugulu et al., 2014, Table 1 and Fig.