Carnian (Late Triassic) conodont faunas from south‐western China and their implications

Abstract

Conodonts are important index fossils for supra-regional correlation especially in the Triassic. However, early Carnian conodonts are comparatively poorly known in South China. In this study, conodont biostratigraphy and taxonomy are investigated at three sections in the provinces of Yunnan and Guizhou. Two genera and 23 species are identified, including 4 new species: Quadralella (Q.) postica sp. nov., Q. robusta sp. nov., Q. wignalli sp. nov. and Q. yongningensis sp. nov. Five conodont zones are recognized. They are, in ascending order, the Paragondolella foliata Zone, Q. polygnathiformis Zone, Q. praelindae Zone, Q. aff. auriformis Zone and Q. robusta Zone. Conodonts are reasonably diverse and abundant in the upper Zhuganpo Formation (Julian 1) but decrease sharply in both species richness and diversity towards the Wayao Formation (Julian 2 and younger). It is most likely that this change was caused by climate warming and marine anoxia during the Carnian Humid Episode.

The Ladinian–Carnian conodont fauna at Yize, Yunnan, southwestern China, with implications for conodont palaeoecology and palaeogeography

“…sp., YZ-63-008; 21 – Q. jiangyouensis (Wang & Dai, 1981), YZ-79-026; 22 – Q. tadpole (Hayashi, 1968), YZ-95-1-006; 23 – Q. robusta Zhang, Sun & Lai in Zhang et al . 2018 b , YZ-95-2-022; 24 – Q. polygnathiformis (Budurov & Stefanov, 1965), YZ-95-1-005. …”

“…Q. acuminata and Q. lobata are also known in the Zhuganpo Fm from Guizhou and Yunnan in southwestern China as well as in Japan (Zhang et al . 2017, 2018 b , 2019).…”

Conodont size reduction and diversity losses during the Carnian Humid Episode in SW China

“…Diverse Middle to Late Triassic carbonate deposits are well developed in southwest China (Yang et al 1982Enos et al 2006. The studied sections include Long Chang (Sun et al 2016), Yongyue (Zhang et al 2017) and Caizitang (Zhang et al 2018) which all have established conodont biostratigraphy. The Long Chang and Yongyue sections are situated in the Zhenfeng area, of southwestern Guizhou Province, which was located at the transition between the margin of Yangtze Platform and Nanpanjiang Basin (Enos et al 2006).…”

“…auriformis Zone, Quadralella robusta Zone, Quadralella noah Zone and Quadralella ex gr. carpathica Zone (Sun et al 2016;Zhang et al 2017Zhang et al , 2018. The level of the CHE in South China has been identified, using a combination of biostratigraphic and chemostratigraphic data (Sun et al 2016), at the transition of the Zhuganpo and Wayao formations.…”

The Carnian pluvial episode (Late Triassic): new insights into this important time of global environmental and biological change

“…The geological record of Late Triassic conodonts has expanded sharply in the last years, as new Carnian successions from China were studied in detail and brought to the attention of the international scientific audience (e.g. Sun et al 2016;Zhang et al 2018b). For this thematic set, Zhang et al (2018a) exploited a rich collection of conodonts from Chinese sections to explore a neglected facet of the evolution of conodonts during the Carnian, i.e.…”