Upper Devonian (Famennian) and Lower Carboniferous (Tournaisian) Ammonoids from Western Junggar, Xinjiang, Northwestern China—
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Palaeobio Palaeoenv DOI 10.1007/s12549-014-0171-y ORIGINAL PAPER Upper Devonian (Famennian) and Lower Carboniferous (Tournaisian) ammonoids from western Junggar, Xinjiang, northwestern China—stratigraphy, taxonomy and palaeobiogeography Pu Zong & R. Thomas Becker & Xueping Ma Received: 31 March 2014 /Revised: 18 June 2014 /Accepted: 17 July 2014 # Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg 2014 Abstract Seven ammonoid levels/assemblages are recognised with the orbiculare Zone (UD IV-C) of North Africa, which in the Devonian (Famennian) and Carboniferous (Tournaisian) also contains very large clymeniids and goniatites. The third of the northwestern Junggar Basin, Xinjiang, northwestern regional assemblage consists of rare Gonioclymenia sp. and a China. Eleven genera and 20 species, including six new species related, more evolute form. The fourth assemblage is a pecu- (Becanites sp. nov., Protactoclymenia junggarensis sp. nov., liar Cymaclymenia “Mimimitoceras” fauna, including Prot. magna sp. nov., Cyrtoclymenia? parallela sp. nov., C. striata (Münster) s.l., C. cf. involvens Lange, Sporadoceras impressum sp. nov. and “Mimimitoceras” Sporadoceras sp., “Mimimitoceras” cf. geminum Korn, transiens sp. nov.) are described from the Hongguleleng and “M.” transiens sp.nov.andM. cf. rotersi Korn, most of which Heishantou formations in the Bulongguoer, Hebukehe, Emuha are discovered for the first time in the vast Junggar and adjacent and Hashatu sections. The first assemblage is characterised by areas. Based on conodont (associated Protognathodus fauna) Platyclymenia subnautilina (Sandberger), Prionoceras frechi and palynomorph data (LN Zone), this assemblage corresponds (Wedekind) and Sp. impressum sp. nov. It is assigned to the to the lower Hangenberg Event Interval (UD VI-E). Rare basal upper Famennian Pl. annulata Zone (UD IV-A) records from a fifth level suggest that cymaclymeniids survived and indicates that the global, transgressive Annulata Event regionally into the conodont Pr. kockeli Zone, as in other enabled the first spread of ammonoids to the region. The regions. The sixth level consists of a single Lower second assemblage is characterised by large-sized Tournaisian Acutimitoceras (Stockumites)?. The seventh level Cyrtoclymeniaceae (Protactoclymenia and Cyrtoclymenia?) also has a low diversity and includes Weyerella angularia and Sporadoceras aff. muensteri (Münster) and correlates (Liang and Wang) and Becanites sp. nov. in the Emuha section. It falls in the Middle Tournaisian, as do Weyerella faunas that This article is registered in Zoobank under urn:lsid:zoobank.org: were previously reported from the region. The endemic species pub:50406ADD-F879-4011-887F-C5FD86633829. and the distinctive lack of otherwise widespread genera provide P. Zong a strong regional signature of the overall ammonoid fauna. Institute of Geology, Chinese Academy of Geological Sciences, 26 Baiwanzhuang Road, Beijing 100037, China Keywords Ammonoids . Annulata Event . Hangenberg Event . Western Junggar . Hongguleleng Formation . P. Zong Key Lab of Stratigraphy and Paleontology, Ministry of Land and Heishantou Formation Resources of China, Beijing 100037, China R. T. Becker Introduction Institut für Geologie und Paläontologie, Westfälische Wilhelms-Universität, Corrensstraβe 24, 48149 Münster, Germany Devonian and Carboniferous strata are well-exposed in west- X. Ma (*) ern Junggar, Xinjiang, northwestern China, where abundant Key Laboratory of Orogenic Belts and Crustal Evolution, School of benthic invertebrate fossils, such as brachiopods, rugose Earth and Space Sciences, Peking University, 5 Yiheyuan Road, Beijing 100871, China corals, echinoderms and trilobites, have been described (e.g. e-mail: [email protected] Zhang 1985; Liao and Cai 1987; Wang and Zhao 1987;Cai Palaeobio Palaeoenv 1988; Hou et al. 1993;Laneetal.1997; Soto and Lin 2000; dm Conch diameter Waters et al. 2003; further references in Suttner et al. 2014). dm/2 Half of conch diameter However, pelagic and nektonic fossils, such as ammonoids, L lobe Lateral lobe outside or at the umbilical are rare. Wang (1983) described the first ammonoid, seam Cymaclymenia cf. striata (Münster) (a single incomplete and uw/2 Half of umbilical width compressed specimen) from the “Hongguleleng Formation” WER Whorl expansion rate=[dm/(dm − ah)]2 and Gattendorfia sp. from the Heishantou Formation of the wh Whorl height Carboniferous in the Hongguleleng area of Hoboksar. ww Whorl width Subsequently, Sheng (1984) described a new gattendorfiid A. Acutimitoceras (G. parapplanata) from the eastern Junggar (Zhifang region). Bec. Becanites Liang and Wang (1988)illustratedaGattendorfia sp. from C. Cymaclymenia Hongguleleng of the Hoboksar region, which they subse- Cyrto Cyrtoclymenia quently (Liang and Wang 1991) named as a new species, E. Enkebergoceras G. angularia. They also listed Cymaclymenia cf. striata G. Gattendorfia (Münster) and Imitoceras sp. from the top of the Devonian Go. Gonioclymenia in their stratigraphic description [based on a previously infor- I. Imitoceras mally published report by the Regional Geological Survey K. Kazakhstania Team, Bureau of Geology (and Mineral Resources) of M. Mimimitoceras Xinjiang]. Xu et al. (1990) mentioned a Gattendorfia from Pl. Platyclymenia the Emuha section of the Hoboksar region. Ruan (1995a) Pr. Prionoceras reviewed the Carboniferous ammonoid faunas of China and Prot. Protactoclymenia commented on the known Xinjiang records. In a separate Proto. Protocanites chapter (Ruan 1995b) he added many new species from the R. Rectimitoceras Heishantou Formation of three localities of northern Xinjiang Sp. Sporadoceras and placed them in three subgenera of Gattendorfia.Healso St. Stockumites showed that these are associated with rare Protocanites and W. Weyerella the earliest muensteroceratids (Xinjiangites). P. Protognathodus Numerous and diverse ammonoids have been collected from several horizons ranging from the Devonian to Carboniferous during our detailed field investigation in the Locality and stratigraphy last few years, especially those in the Famennian (approxi- mately from the upper Upper trachytera Zone to Lower All of the specimens were collected from the Hongguleleng expansa Zone interval), which are the first records in the vast Formation and the Heishantou Formation in the Bulongguoer, Junggar area. A few specimens have been illustrated in Hebukehe, Emuha and Hashatu sections. These sections are open nomenclature in a preliminary report (Ma et al. 2011). located near the town of Hoxtolgay, Hoboksar Mongolian Some field photos of both rock sequences and ammonoids Autonomous County, Xinjiang Uygur Autonomous Region from the basal Wulan Member are presented in the report of (Fig. 1). Zong et al. (2014), and these have been referred to in the brachiopod studies of Zong and Ma (2012) and Zong et al. The Bulongguoer section (2012). This section is located at the hills 1.5 km west of the Bulongguoer Reservoir and 30 km northeast of Hoxtolgay Abbreviations town. It is the type section for the Hongguleleng Formation and has been studied by many investigators (e.g. Liao and Cai The classification of Tournaisian substage subdivision follows 1987;Xuetal.1990; Zhao and Wang 1990;Xiaoetal.1992; the classical, formal Belgian scheme, with the Middle Zhao and Peng 1992; Hou et al. 1993;Xia1996; Soto and Lin Tournaisian sensu denoted as Tn 2 and the Upper 2000; Waters et al. 2003;Chenetal.2009;ChenandYang Tournaisian denoted Tn 3. 2011;Maetal.2011, 2013; Suttner et al. 2014). We measured Other abbreviations are presented in the following list: the Bulongguoer section in detail and divided it into 16 units (Fig. 2; see stratigraphic description in Ma et al. 2013). The A lobes Adventitious lobes Hongguleleng Formation (Units 2-9a) contains abundant ben- ah Apertural height thic fossils predominated by brachiopods (cyrtospiriferids), uw Umbilical width corals, trilobites, crinoids, blastoids and bryozoans. The Palaeobio Palaeoenv (a) (b) 86° Jeminay Burqin Altay 88° Fuhai Hoboksar Figure1(b) Heishantou Karamay Hoboksar ° Urumqi 47° 47 Xinjiang Beijing Utubulak 2 3 1 4 06020 40 k m Hoxtolgay 86° 88° N (c) Haerbulong Hebukehe A River F Saerbagende Mts. C 0 500 1000 km E D 1050 National Path 1000 Road 217 950 Section location: 1. Saerbagende Mountain; 900 005. 1km 2. Bulongguoer section; 3.. Emuha section; 4 Hashatu section Longkou contour line A : Hebukehe− A section etc. Fig. 1 Locations of studied sections. c Base map is based on Zhao (1986) recent detailed study by Suttner et al. (2014)alsoin- discordant in terms of its relationship with the Hongguleleng cluded data on microfacies and geochemistry and Formation (e.g. Xia 1997). It is considered to be a synonym showed that there are scarcely conodonts in the upper/ of the latter by many workers (see Ma et al. 2013 and uppermost Famennian. The lower part of the overlying references therein). Heishantou Formation (Units 9b-15) contains a Syringothyris- Two ammonoid fossils were obtained (sample XZ548: Spirifer brachiopod fauna; it is still Devonian in age, based on Protactoclymenia junggarensis sp. nov.) from the top of the correlation with the Hebukehe-E section (Zong and Ma Unit 11 in the Hebukehe-E section, and the lithology is green 2012). sandy limestone. The overlying Unit 12, which is about 15 m The lower part of Bed 5-2 is the only layer yielding thick, mainly consists of purplish red sandy limestone and ammonoids in this section (sample XZ448). Bed 5-2 is com- silty mudstone