POST-CONGRESS EXCURSION

Triassic Marine- Paleontology and Stratigraphy of the Guizhou- Plateau, southwestern China

Date: June 22-27 Excursion Leaders: Profs. Li Jinling & Jin Fan, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China; [email protected], [email protected] Profs. Wang Xiaofeng & Chen Xiaohong, Yichang Institute of Geology and Mineral Resources, China Geological Survey, Yichang 443003, Hubei, China; [email protected], [email protected] Profs. Sun Yuanlin & Jiang Dayong, Geological Museum and Department of Geology, Peking University, Beijing 100871, China; [email protected], [email protected] Minimum number of participants: 15 persons Maximum number of participants: 35 persons

Rationale:

Marine deposits of the are widespread in southwestern China, especially in central and southern Guizhou Province. The stratigraphic and geologic significance of these areas has been realized by geologists over the last century. Today, these areas are famous for their abundant perfectly preserved marine fossils, e.g. reptiles, fishes, pelagic crinoids. The Triassic vertebrate fossils from Guizhou and adjoining area were first discovered in 1957. At the end of the 20th century, associated with the “fossil fever” in China, large amounts of well-preserved marine were excavated in this region. These new discoveries included the representatives of almost all the major Triassic vertebrate groups, such as sauropterygians, , thalattosaurs, protorosaurs, varied “subholosteans”, modern halecomorphs and basal teleosts. Study of these perfectly preserved skeletons has significantly expanded our knowledge of the evolution and paleobiogeography of marine vertebrates. The Triassic vertebrate fossils in Guizhou and adjoining area are mostly found from three horizons, consequently they are attributed to three faunas, which are popularly know as “Panxian fauna” (late ), “Xingyi Keichousaurus fauna” (late Ladinian) and “Guanling fauna” (early Carnian) after their main localities. This excursion will focus on the classical sections of the Triassic marine strata and intensively investigated fossil localities of marine reptiles in Guanling, Xingyi and Panxian of Guizhou Province, and Luoping of Yunnan Province. Presently, Guanling, Xingyi and Panxian have been chosen as the national geoparks of China (Fig. 1).

Itinerary: The trip begins in Beijing and ends in Kunming (the capital city of Yunnan Province), and will include all main vertebrate fossil localities in Guanling and Xingyi of Guizhou, and Luoping of Yunnan. Participants are expected to leave Beijing on June 22 after the IPC meeting, and they will arrive in Kunming on June 27. There is an additional locality in Panxian of Guizhou for participants who are interested. Unfortunately, it is inaccessible in case of bad weather. If this day is added, it will take another day to reach the destination.

Fees: The cost of the trip is US$800, including 6-nights of accommodation (double-bed room shared by two persons), all meals from June 22 to 27, vehicle, tickets for museums and scenic sites, field trip guidebook, and economic airfare from Beijing to Guiyang on June 22. Participants are responsible for their airfare from Kunming to their home. The extra cost for the optional trip to Panxian of Guizhou is US$80.

Fig. 1 Major stops and route of the post-congress excursion A4

June 22: Travel from Beijing to Guanling Stop at the Huangguoshu Waterfall will be arranged on the way to Guanling. Participants will have an opportunity to appreciate the charms of the largest waterfall in Asia.

June 23-24: Stratotype sections of the formations bearing the three faunas and a unique Late Triassic fossil- lagerstätte in Guanling of Guizhou Guanling, located in southwestern Guizhou Province, is considered a key area for studying the Middle and lower Upper Triassic stratigraphy and palaeontology in southwestern China. Middle and Upper Triassic rocks are widespread in this area and are subdivided into Guanling, Yangliujing and Falang Formations * (Fig. 2). The stratotype sections of these formations, Fig. 2 Middle–Upper Triassic Stratigraphic sub- division of the Guanling area, with the indicator of the except for the Laishike Member of the interval yielding Guanling fossillagerstätte (GFL) Falang Formation, are well exposed along the highway 320 from Yongning Town to Huangtutang Village in Guanling. A unique Late Triassic (early Carnian) fossillagerstätte is known from the Wayao Member of the Falang Formation in this area (Fig. 3). This fossillagerstätte is charac- terized by the occurrence of

Fig. 3 Distribution of the Guanling fossil lagerstätte numerous well-preserved marine reptiles (e.g. ichthyosaurs, thalatto- saurs, and placodonts) and pelagic crinoids. Associated fossils include ammonites,

* The Falang Formation includes Zhuganpo, Wayao and Laishike Members, which are taken as independent formations in some literature; and the Wayao Member is also known as the Xiaowa Formation bivalves, conodonts, brachiopods, elasmobranch ichthyoliths, fishes and plants. In China, this characteristic fossillagerstätte is only found in Guanling and adjacent areas, and nowhere else do they preserve so many perfect marine reptile skeletons and pelagic crinoids. The only comparable localities are those from the Anisian/Ladinian () Besano Formation in the Southern Alps and the Toarcian (late Early ) Posidonia Shale of Holzmaden in Germany.

Fig. 4 Wayao Member of the Falang Formation Fig.5 Biggest pseudoplaktonic Traumatocrinus yielding Guanling fossillagerstätte attached to drift wood The trip will visit the typical Middle to Upper Triassic succession and a field museum in the National Geopark of Guanling Biota (Fig. 4). In the museum, participants can see the fossils of the Guanling lagerstätte in their original position on the black shale and mudstone bedding planes (Fig. 5). Guanling is a Miao and Buyi autonomous county covering 1468 square kilometers. Among the 320,000 population, 60% are minorities. Over there, participants will have the opportunity to enjoy the beautiful karst landscape of Huajiang Gorge, the so called “a crack of the earth”, on the Beipan River.

June 25: Keichousaurus fauna and the upper Middle Triassic sequence at Lüyin, Dingxiao, Xingyi, Guizhou Lüyin of Dingxiao is the first discovered locality of Triassic marine vertebrates in China. It is also the country of Keichousaurus (Fig. 6). In Fig. 6 Lüyin Village and its dragon—Keichousaurus nearly half a century, many well-preserved reptile and fish fossils have been discovered at this locality. Recently, lots of new vertebrate specimens of the same horizon have also been found from a vast area around Dingxiao (Fig. 7a), e.g. Wusha of Xingyi, Anlong of Guizhou, Luoping and Fuyuan of Yunnan. This indicates that the Keichousaurus fauna is widely distributed in southwestern Guizhou and eastern Yunnan. Up to now, the known forms of the Keichousaurus fauna include the representatives of almost all the major Triassic marine vertebrate groups, such as pachypleurosaurs, nothosaurs, placodonts, ichthyosaurs, thalattosaurs, protorosaurs, varied “subholosteans”, modern halecomorphs and basal teleosts. It seems that this fauna is most diversified among the three Fig. 7 (a) Occurrence of vertebrate fossils in the Zhuganpo Member around Dingxiao; (b) geological map of the Dingxiao Triassic faunas in Guizhou and area; (c) sequence of the Zhuganpo Member at Lüyin Village of its adjacent area. Dingxiao The Early and Middle Triassic deposits are widespread in the Dingxiao area (Fig. 7b). This excursion will focus on the sequence of the Zhuganpo Member of the Falang Formation at Lüyin Village of Dingxiao, which is more then 70 m thick and mainly composed of dark grey thick to thin-bedded micrite. The vertebrate fossils of the Keichousaurus fauna are mostly found from a 3.57 m thick interval of thin-bedded micrite and muddy micrite in this member, about 50 m above the Yangliujing Formation (Fig. 7c). In this trip, participants will also visit the Museum of Keichousaurus Fauna where are exhibited the vertebrate fossils from this area both at home and in the field. Before leaving Xingyi, an adventure is arranged in the Malinghe Gorge, which is a national scenic spot near Lüyin Village.

June 26: Middle and Upper Triassic sequence at Banqiao, Luoping, Yunnan Banqiao of Luoping is in the eastern Yunnan Fig. 8 Location in Luoping, Yunnan Province, about 2 hours away by car from Xingyi of Guizhou. There is a well exposed Triassic sequence from the Lower Triassic Yongningzhen Formation to the Upper Triassic Huobachong Formation. Three sites (Fig. 8) are chosen for this excursion to focus on the sequence from the upper part of the Yangliujing Formation to the Falang Formation (Fig. 9). The upper part of the Yangliujing Formation consists of dark to dark grey medium- to thin-bedded argillaceous, dolomitic and laminated dolostone, with a thickness about 50-60 m. Abundant specimens of Keichousaurus hui and fishes have been recovered from the top of this member in a quarry at Site 1 (Fig. 10). Specimens of thalattosaurs (cf. Askeptosaurus) and lariosaurs (Lariosaurus sp.) were excavated in a horizon about 20 m below the Keichousaurus hui bed at Site 3. Specimens of marine reptiles, similar to Keichousaurus, have also been found near the base of the upper part of the Yangliujing Formation in a quarry at Site 3 (Fig. 11). The Falang Formation can be subdivided into three members: Zhuganpo, Wayao and Laishike,

Fig. 9 Middle-Upper Triassic sequence from base to top. The Zhuganpo Member is about and the distribution of some key fossils 90 m thick and composed of grey micritic limestone, around Banqiao, Luoping, Yunnan nodular limestone and bioclastic limestone with some chert concretions, containing abundant ammonoid and nautiloid cephalopods (such as Anolcites clionoidis Wang et He, Protrachyceras sp., Germanonautilus brooksi Smith, and some yet undescribed taxa) and conodonts. The Wayao Member is characterized by the grayish yellow to brownish yellow colored fine grained clastic Fig. 10 Keichousaurus bed at Site 1 deposits (siltstone and silty shale) with some intercalations of thin-bedded marl and limestone, containing abundant ammonoid and nautiloid cephalopods (Germanonautilus, Protrachyceras, Trachyceras, etc.), bivalves, and a few well preserved crinoids and brachiopods. This member is about 100 m thick. Visitors can collect fossil ammonites and bivalves from the siltstone in the middle part of this member at Site 2. The Laishike Member consists of sandstone, siltstone and silty shale with thickness about 600 m thick, containing fossil bivalves, ammonites and plants. The ammonites and conodonts suggest that the Zhuganpo Member lies within the transition bed from the Ladinian to Carnian Stage.

Fig. 11 Quarry of the upper part of the Yangliujing Formation at Site 3, which yields new marine reptiles

Optional trip: Panxian Fauna and the Middle Triassic sequence at Yangjian, Xinmin, Panxian, Guizhou The Panxian Fauna is a newly discovered anoxic-type Middle Triassic marine vertebrate fauna in Guizhou. The type locality of this fauna is near Yangjian Village, Xinmin, Panxian (Figs. 12, 13). We can reach this site in about 3-4 hours by car from the downtown of Xingyi. There is a well exposed Triassic sequence Fig. 12 Topographical and geological map around Yangjian Village, Xinmin, Panxian, from the middle-upper part of the Yongningzhen Guizhou Formation to the base of the Yangliujing Formation around Yangjian. This excursion will focus on the Middle Triassic Guanling Formation. The Guanling Formation, about 530-560 m thick, can be subdivided into three members. The lower member mainly consists of variegated (red, grayish green and yellow) siltstone, silty shale and mudstone intercalated with white grey dolostone and dolorudite. There is a layer of 2-3 m thick, white to greenish yellow bentonite at the bottom. The middle member is composed of grey worm-like, argillaceous limestone, calcirudite, dolomitic Fig. 13 Hill yields fossil marine reptiles limestone and bioclastic limestone, with a few intercalations of light grey claystone and micritic dolostone. Trace fossils and bivalves are common in the worm-like limestone. The upper member consists of grey micritic, argillaceous, worm-like, dolomitic limestone and argillaceous banded limestone, with a few intercalations of dolostone and bentonites. The Panxian Fauna is recovered from a ca. 4 m thick interval of dark grey muddy to dolomitic limestone in this member, about 50 m below the Yangliujing Formation (Fig. 14). Five layers of bentonite, varying from 0.5 to 10 cm thick, can be observed in outcrops in the fossil-bearing interval. Abundant completely articulated vertebrate fossils have been excavated, including two mixosaurid ichthyosaurs, two nothosaurid sauropterygians, one protorosaur, and some fishes. Several articulated and in situ preserved

specimens of mixosaurid ichthyosaurs can be observed Fig. 14 Sequence of the upper member of the Guanling Formation on the excavation site of Peking University-University at Yangjian Village, Xinmin, of California at Davis. The coexisted invertebrate Panxian, Guizhou fossils include brachiopods and bivalves. The conodont analysis suggests that the age of the fauna is early to middle Pelsonian of Anisian, Middle Triassic within the conodont Nicoraella kockeli Zone.

June 27: Bus trip from Luoping to Kunming The last stop of this trip is going to visit “the village of karst caves” at Jiuxiang of Yiliang, the largest cave group system with the most numerous karst caves in China. Participants will have an opportunity to wander in the wonderful subterranean world.