T287 The Cenozoic Evolution of Tibet—How Do We Unify Seemingly Contradictory Evidence?

Wednesday, 7 November 2018
1:30 PM - 5:30 PM
Room 243

TSUGA SEED CONES FROM THE LATE PALEOGENE OF SOUTHWESTERN CHINA AND THEIR EVOLUTIONARY AND PALEOENVIRONMENTAL IMPLICATIONS

Paper number: T287-6
Program: Technical Sessions
Time: 2:40 PM – 2:55 PM

Authors

  • Meng-Xiao Wu Presenting Author
    Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Yunnan
  • Meng-Xiao Wu Presenting Author
    University of the Chinese Academy of Sciences, Beijing
  • Jian Huang
    Xishuangbanna Tropical Botanical Garden, CAS, Yunnan
  • Tao Su
    Xishuangbanna Tropical Botanical Garden, CAS, Yunnan
  • Qin Leng
    Bryant University, Smithfield, RI
  • Zhe-Kun Zhou
    Xishuangbanna Tropical Botanical Garden, CAS, Yunnan
  • Zhe-Kun Zhou
    Kunming Institute of Botany, Chinese Academy of Sciences, Kunming

Abstract

The fossil record of Tsuga (Pinaceae) can be traced back to the Late Cretaceous in North America and Eurasia. However, in southwestern China, a critical region that experienced rapid Cenozoic uplifting and climate changes due to the formation of the Himalayas and the Qinghai–Tibetan Plateau, fossil record of this genus has been sparse and confined in deposits of late Miocene or younger ages. Recently, six well-preserved Tsuga ovuliferous/seed cone impression fossils were discovered in late Paleogene lacustrine beds in two localities in southeastern China: Three specimens were from the late Eocene (34.64 ± 0.8 Ma) Lawula Formation at Kajun Village, Mangkang County, eastern Tibet and the other three were from the early Oligocene (32 ± 1 Ma) mudstone at the Lühe Basin, Lühe Town, Nanhua County, Yunnan Province. These two sites are both located at the southeastern edge of the Qinghai–Tibetan Plateau, ~800km apart from each other. Based upon comparisons with seed cones of all living and fossil species of Tsuga, we established T. asiatica M. X. Wu et Z. K. Zhou sp. nov. to accommodate five specimens (two from the Kajun site and three from the Lühe site), leaving one from the Lühe site to be assigned to T. cf. dumosa (D. Don) Eichler. Both qualitative and quantitative (nonmetric multidimensional scaling) comparisons suggested that T. asiatica shares more similarities with the basal species of the genus. The establishment of late Paleogene fossil records of Tsuga in southeastern China enriched our understanding of the evolutionary history of this coniferous genus. Along with information provided by associated plants from these fossil floras, these fossil cones from deposits at the current elevations of 3,910 m above sea level (a.s.l) (the Kajun site) and 1,882 m a.s.l (the Lühe site) offer invaluable information regarding paleoenvironment and paleoclimate in this critical area. The age and location of these fossils bear strong implications to the interpretation of the uplifting of the Himalayas and the Qinghai–Tibetan Plateau and monsoonal climate system that it controls.

Geological Society of America Abstracts with Programs. Vol. 50, No. 6

doi: 10.1130/abs/2018AM-322773

© Copyright 2018 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.