New record of Jurassic Xenoxylon wood from Gansu, northwestern China, and its palaeoclimatic implications

ABSTRACT

Fossil wood is a significant proxy for terrestrial palaeoclimate and palaeogeography. Abundant and diversified Mesozoic fossil wood has been documented in China. However, there are limited reports of Jurassic fossil wood records from northwest China. Herein, several calcified wood fossils are described in anatomical detail, from the Middle Jurassic (Bajocian to Callovian) Xinhe Formation in Gansu Province. They were identified as two species of the fossil wood genus Xenoxylon Gothan of Coniferales, namely X. latiporosum (Cramer) Gothan and X. peidense Zheng et Zhang. The newly collected material represents the first record of Jurassic petrified wood from Gansu Province. Based on the palaeoclimatic implication of Xenoxylon, we propose that the Baojishan Basin may have experienced a distinct short-term cooling during the Middle Jurassic. We analysed the fossil diversity and spatial-temporal distribution of Xenoxylon species in China. A total of 15 Xenoxylon species have been documented in China. These occurred from the Late Triassic to Late Cretaceous, but flourished from the Jurassic to Cretaceous intervals. Geographically, they are distributed across 13 provinces, mainly in northeast China. Significantly, this record expands the distribution of this important climate indicator taxon.

KEYWORDS:

• Jurassic
• fossil wood
• Xenoxylon
• palaeoclimate
• Gansu Province

Funding

This study is financially supported by the National Natural Science Foundation of China [grant numbers 41790454 and 42072009]; the Strategic Priority Research Program of Chinese Academy of Sciences [grant numbers XDB26000000] and the State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology, CAS) [grant numbers 20191103, 213112 and 193130].

Acknowledgments

We are grateful to the editor Dr. Dyke, the two anonymous reviewers for their effort in reviewing the manuscript and providing valuable comments and suggestions. We thank Prof. Zikun Jiang (Chinese Academy of Geological Sciences) and Dr. Luliang Huang (Sun Yat-sen University) for their helpful discussion and modification of the manuscript. We are grateful to Mr. Shuai Shao and Zhenyu Wu of Shenyang Normal University who helped making the thin sections. Special appreciations are due to Mr. Shicheng Ruan and Hailong Ma (Lanzhou University) for their support on field survey. We also thank Yansen Chen (NIGPAS, Nanjing) for useful suggestions on the software of ArcGIS.

Disclosure statement

No potential conflict of interest was reported by the author(s).