A high-resolution timescale for the Miocene Shanwang diatomaceous shale lagerstätte (China): development of Wavelet Scale Series Analysis for cyclostratigraphy

Research output: Contribution to journalArticlepeer-review

Authors

  • Jifeng Yu
  • Xinlong Pang
  • Wenzhao Fu
  • Mingmei Liang
  • Zongkai Jiang
  • Xiuli Zhao
  • Wenyan Qiao
  • Suo Shi
  • Diandong Zhang
  • Huitao Cao
  • Haibo Jia
  • Yadong Wang
  • Xiaoke Hu
  • Rui Zhang

Colleges, School and Institutes

External organisations

  • Shandong University of Science and Technology
  • Liaoning Technical University
  • School of Geography/Envrn. Sciences
  • China University of Petroleum

Abstract

The Miocene aged Shanwang Formation from the Shanwang National Geopark in China represents a succession of lacustrine diatomaceous shales containing an abundant and diverse biota with lagerstätte fossilization of soft tissues. To date, the Shanwang Formation has not been investigated for cyclostratigraphy nor has it been dated with high precision methods. Now we use thorium data as a paleoenvironmental and paleoclimatic proxy to conduct a detailed cyclostratigraphic analysis. A new and simple cyclostratigraphic method, Wavelet Scale Series Analysis (WSSA) is developed to recognize Milankovitch cycles. A total of three short eccentricity and fifteen precession cycles are identified; obliquity cycles are not apparent. In the sedimentary succession, the corresponding precession and short eccentricity cycles are 1.17 m and 4.98 m thick respectively, with this verified by Correlation Coefficient (COCO) analysis and Multitaper-Method (MTM) spectral analysis. We estimate the studied interval was deposited over a duration of 0.3 Myr with a depositional rate of c. 5.7 cm/kyr. Paleomagnetic and radio isotope dating data shows that the diatomaceous shale was deposited during Chron C5En, which places it at approximately 18.5 Ma during the Burdigalian stage of the Early Miocene, rather than in the Middle Miocene as previously thought. The Shanwang lagerstätte biota therefore predates the Middle Miocene Climate Optimum (MMCO) and did not form within it. The geological time scale with a high resolution of 20 kyr was set accordingly.

Bibliographic note

Funding Information: Thanks are given to Professor A.J. (Tom) Van Loon for his constructive suggestions on an earlier version of the manuscript. Thanks are also given to Mr. Gang Zhao for his help in the field. This work was financially supported by the National Natural Science Foundation of China (41472092) and the Scientific and Technological Innovation Project of the Qingdao National Laboratory for Marine Science and Technology (No. 2016ASKJ13).

Details

Original languageEnglish
JournalGeosciences Journal
Early online date8 Jan 2021
Publication statusE-pub ahead of print - 8 Jan 2021

Keywords

  • Burdigalian, Chron C5En, Milankovitch cycles, geochronology, spectral analysis