Late Visean to Gzhelian foraminiferal assemblages from the Paleo-Tethyan seamount-type carbonates in the Changning-Menglian Belt, westYunnan, southwest China

The Changning-Menglian Belt of West Yunnan, Southwest China is known as a closed remnant of the Paleo-Tethys. Carboniferous to Permian carbonates of mid-oceanic seamount origin from the central part of this belt is studied at the Yutangzhai Section for a thorough understanding of the foraminiferal distribution in this Paleo-Tethyan atoll. About 1750 thin sections were prepared from 190 specimens for the Carboniferous part. Twenty one foraminiferal assemblages, ranging from the Late Visean (Middle Mississippian) to the Gzhelian (Late Pennsylvanian) are recognized. Taxa of assemblages are: (1) Eostaffella, Endothyra, Bradyina, Vissariotaxis, Howchinia, Mediocris, Archaediscus, Janischewskina, Endothyranopsis (Late Visean), (2) Monotaxinoides, Howchinia, Endostaffella, Eostaffella ikensis, Turrispiroides (Serphukovian) (3) Millerella, Pseudoendothyra (Early Bashkirian) (4) Pseudostaffella (Semistaffella) (Middle Bashkirian) (5) Pseudostaffella antiqua (early Late Bashkirian), (6) Profusulinella (late Late Bashkirian) (7) Eofusulina, Pr. pseudorhomboides (Early Moscovian), (8) Pr. prisca, Fusulinella subpulchra (Early Moscovian), (9) Beedeina (early Middle Moscovian), (10) F. vozghalensis, F. eopulchra (early Middle Moscovian), (11) F. bocki, F. pseudobocki (Late Moscovian), (12) Protriticites sp. A (Latest Moscovian), (13) Pseudotriticites? (Early Kasimovian), (14) Obsoletes (Early Kasimovian), (15) Protriticites sp. B (Early Kasimovian), (16) Montiparus, Quasifusulinoides (Early Kasimovian), (17) Triticites, Rauserites (Late Kasimovian) (18) Triticites, Rauserites, Schwageriniformis (Early Gzhelian), (19) Daixina, Schwageriniformis (Middle Gzhelian), (20) Globifusulina, Daixina, Nonpseudofusulina? (Late Gzhelian) (21) Ruzhenzevites,Ultradaixina? (Late Gzhelian). Judging with the steady diversity increase of the foraminifers, it is concluded that the paleo-climate in those atolls did not seem significantly changed throughout the Carboniferous. 34th International Geological Congress Unearthing our Past and Future — Resourcing Tomorrow 372