Ichnofabrics and their environmental interpretation from the fluvial deposits of the Middle Triassic Youfangzhuang Formation in Western Henan, Central China

Abstract

Fluvial deposits from the Middle Triassic Youfangzhuang Formation in Henan Province, China contain a low-diversity trace fossils. Vertical dwelling burrows of opportunists dominate in active channel, whereas horizontal deposit-feeding, grazing, and vertical dwelling burrows occur in overbank deposits. Seven recurrent ichnofabrics were distingushed. The Palaeophycus tubularis ichnofabric preserves below scour interface between two fluvial cycles. The Skolithos linearis ichnofabric forms in middle to high-energy, soft substrates in the middle and upper parts of active channel deposits under semi-arid climate. The Skolithos linearis-Planolites montanus ichnofabric occurs in the sediments just a little above the Skolithos linearis ichnofabric and is formed in middle-energy, soft substrates in the upper part of active channel deposits. The Planolites montanus ichnofabric is mostly preserved in association with medium- to thick-bedded brown-red silty mudstones or siltstones in low-energy, perennial muddy bottom ponds in overbank settings. The Taenidium barretti ichnofabric is interpreted as periodically exposed ephemeral ponds or low-energy distal floodplain. The Skolithos isp. ichnofabric commonly occurs in middle to high-energy firm ground of proximal foodplain or crevasse-splay deposits. The root trace ichnofabric occurs in the crevasse splay deposits. The presence of thin palaeosols and the abundance of calcretization in mudstones indicate a seasonal climate ranging from humid to semi-arid, with high temperature, rainfall, and well-defined dry and wet seasons.

Keywords

trace fossil / ichnofabric / fluvial deposit / environmental interpretation / Middle Triassic / Youfangzhuang Formation

References

[1] Bracken B, Picard M D. Trace Fossils from Cretaceous/Tertiary North Horn Formation in Central Utah. Journal of Palaeontology, 1984, 58(2): 477-487.

[2] Bradshaw M A. Paleoenvironmental Interpretations and Systematics of Devonian Trace Fossils from the Taylor Group (Lower Beacon Supergroup), Antarctica. New Zealand Journal of Geology and Geophysics, 1981, 24: 615-652.

[3] Bromley R G. Trace Fossils: Biology, Taphonomy and Applications, 1996, 2nd Edition London: Chapman & Hall, 361

[4] Bromley R G, Asgaard U. Triassic Freshwater Ichnocoenoses from Carlsberg Fjord, East Greenland. Palaeogeography, Palaeoclimatology, Palaeoecology, 1979, 28: 39-80.

[5] Buatois L A, Mángano M G. The Paleoenvironmental and Paleoecological Significance of the Lacustrine Mermia Ichnofacies: An Archetypical Subaqueous Nonmarine Trace Fossils Assemblage. Ichnos, 1995, 4: 151-161.

[6] Buatois L A, Mángano M G. Trace Fossil Analysis of Lacustrine Facies and Basins. Palaeogeography, Palaeoclimatology, Palaeoecology, 1998, 140: 367-382.

[7] Buatois L A, Mángano M G. Trace Fossils from Carboniferous Floodplain Deposits in Western Argentina: Implications for Ichnofacies Models of Continental Environments. Palaeogeography, Palaeoclimatology, Palaeoecology, 2002, 183: 71-86.

[8] Buatois L A, Mángano M G. Animal-Substrate Interactions in Freshwater Environments: Applications of Ichnology in Facies and Squence Stratigraphic Analysis of Fluvio-Lacustrine Successions. The Application of Ichnology to Palaeoenvironmental and Stratigraphic Analysis, 2004, 228: 311-333.

[9] Buatois L A, Mángano M G. Miller W III. Invertebrate Ichnology of Continental Freshwater Environments. Trace Fossils: Concepts, Problems, Prospects. Elsevier, 2007, 285-323.

[10] Buatois L A, Mángano M G, Wu X T, . Trace Fossils from Jurassic Lacustrine Turbidites of the Anyao Formation (Central China) and Their Environmental and Evolutionary Significance. Ichnos, 1996, 4: 287-303.

[11] Fernandes A C S, Carvalho I S. Ichnofosseis de Intertebrados da Bacia de Sousa (Estado da Pariba, Brasil): A Localidade de Serrote do Letrero. Colecao Chapada do Araripe, 2001, 1: 147-155.

[12] Fitzgerald P G, Barrett P J. Skolithos in a Permian Braided River Deposit, Southern Victoria Land, Antarctic. Palaeogeography, Palaeoclimatology, Palaeoecology, 1986, 52: 237-247.

[13] Frey R W, Pemberton S G. Biogenic Structures in Outcroups and Cores. I. Approaches to Ichnology. Bulletin of Canadian Petroleum Geology, 1985, 33: 72-115.

[14] Genise J F, Mángano M G, Buatois L A, . Insect Trace Fossil Associations in Palaeosols: The Coprinisphaera Ichnofacies. Palaios, 2000, 15: 49-64.

[15] Hasiotis S T. Continental Trace Fossils. SEPM Short Course Notes, 2002, 132.

[16] Hasiotis, S. T., Kraus, M. J., Demko, T. M., 2007. Climate Controls on Continental Trace Fossils. In: Miller, W. III, ed., Trace Fossils: Concepts, Problems, Prospects. Elsevier. 172–195

[17] Hasiotis S T, Mitchell C E, Dubiel R F. Application of Morphologic Burrow Interpretations to Discern Continental Burrow Architects: Lungfish or Crayfish?. Ichnos, 1993, 2: 315-333.

[18] Hobbs H H J. The Crayfishes of Georgia. Smithsonian Comtributions to Zoology, 1981, 318: 1-54.

[19] Hu B, Qi Y A, Zhang G C, . The Ichnocoenoses of Mesozoic-Cenozoic Terrestrial Deposits of Chnia. Acta Sedimentologica Sinica, 2002, 20(4): 574-581.

[20] Kim J Y, Keighley D G, Pickerill R K, . Trace Fossils from Marginal Lacustrine Deposits of the Cretaceous Jinju Formation, Southern Coast of Korea. Palaeogeography, Palaeoclimatology, Palaeoecology, 2005, 218: 105-124.

[21] Morrissey L B, Braddy S J. Terrestrial Trace Fossils from the Lower Old Red Sandstone, Southwest Wales. Geological Journal, 2004, 39: 315-336.

[22] Pemberton S G, Frey R W. Trace Fossil Nomenclature and the Planolites-Palaeophycus Dilemma. Journal of Paleontology, 1982, 56(4): 843-881.

[23] Qi Y A, Hu B, Zhang G C, . Ichnofabrics and Their Environmental Interpretation from Middle Triassic Youfangzhuang Formation, Jiyuan Region, Western Henan Province. Acta Sedimentologica Sinica, 2007, 25(3): 372-379.

[24] Sarkar S, Chaudhuri A K. Trace Fossils in Middle to Late Triassic Fluvial Redbeds, Pranhita-Godavari Valley, South Inida. Ichnos, 1992, 2: 7-19.

[25] Simth R M H. Sedimentology and Ichnology of Floodplain Paleosurfaces in the Beaufort Group (Late Permian), Karoo Sequence, South Africa. Palaios, 1993, 8: 339-357.

[26] Smith P R, Harper A S, Wood M F. Vromwell J C, Link M H. Nonmarine Trace Fossils in the Mio-Pliocene Ridge Basin, Central Transverse Range, California. Geologic History of Ridge Basin, Southern California. SEPM, Pacific Section, 1982, 253-258.

[27] Stanley K O, Fagerstrom J A. Miocene Invertebrate Trace Fossils from a Braided River Environment, Western Nebraska, U.S.A.. Palaeogeography, Palaeoclimatology, Palaeoecology, 1974, 15: 63-82.

[28] Taylor A M, Goldring R. Description and Analysis of Bioturbation and Ichnofabric. Journal of the Geological Society of London, 1993, 150: 141-148.

[29] Woolfe K J. Trace Fossils as Palaeoenvironmental Indicators in the Taylor Group (Devonian) of Antarctica. Palaeogeography, Palaeoclimatology, Palaeoecology, 1990, 80: 301-310.

[30] Wu X T. Trace Fossils and Their Environment Significance in Nonmarine Turbidite Deposits from Jiyuan-Yima Basin, Western Henan. Acta Sedimentologica Sinica, 1985, 3(3): 23-31.

[31] Zhang G C, Zeng Y F, Buatois L A, . Lacustrine Deposits and Associated Trace Fossils in the Upper Part of the Tanzhuang Formation, Jiyuan Basin, Henan Province. Acta Sedimentologica Sinica, 2005, 23(1): 100-107.