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

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