Millennial Resolution Late Miocene Northern China Precipitation Record Spanning Astronomical Analogue Interval to the Future

Abstract

Asian monsoon precipitation heavily influences economic and societal activity for nearly half of the world population (Figure 1), and correct prediction of its future variations requires a complete understanding of its past variations and dynamic mechanisms. The modern climate is characterized by low orbital eccentricity (Laskar et al., 2004). Therefore, knowledge of Asian monsoon precipitation variability under astronomical settings similar to the present interglacial is crucial for understanding its future behavior. The closest interval that Earth's eccentricity was close to the current interglacial is at ca. 440-340 kyr ago of the late Quaternary (Loutre & Berger, 2003). Therefore, many studies focused on the late Quaternary period. For example, both millennial timescale and 100-kyr East Asian summer monsoon (EASM) changes have been detected from the loess sequences on the Chinese Loess Plateau (Fang et al., 1999;Sun et al., 2006Sun et al., , 2012. The dominant viewpoint for the millennial cycles in the late Quaternary is that they are sourced from Northern Hemisphere (NH) ice sheet variation which modulated strength of the Atlantic meridional overturning circulation, and this variation was transported to Asia via westerlies (Fang et al., 1999;Sun et al., 2012). For the 100 kyr cycles, they were normally attributed to be sourced from the variations of NH ice sheets (Sun et al., 2006(Sun et al., , 2015. However, 100-kyr cycles are weak in the East Asian speleothem oxygen isotope records (Cheng et al., 2016; Y. J. Wang et al., 2008), suggesting a dominant forcing of EASM by NH summer insolation at the orbital timescales.

Pinpointing the Mechanism of Magnetic Enhancement in Modern Soils Using High‐Resolution Magnetic Field Imaging

“…We collected horizon soil samples between 5 and 10 cm depth from a transect in the Qilianshan Range representing a range of elevations to study how local temperature and rainfall correlate with differences in magnetic properties (Gao et al., 2021). These soils were developed in loessic parent material on the northern flank of the Qilianshan Range, which receives predominantly summer precipitation.…”

“…These soils were developed in loessic parent material on the northern flank of the Qilianshan Range, which receives predominantly summer precipitation. The highest and lowest elevation samples were collected from 3,533 m (101.85°E, 37.56°N) and 1,859 m (102.3°E, 37.94°N) above sea level (Figure S11 in Gao et al (2021)). The annual mean precipitation at these two sites is 576.6 and 192.8 mm, respectively, based on linear interpolation and extrapolation of annual mean precipitation data obtained between 2011 and 2020 from four meteorological stations at elevations of 2,060 m (242.6 mm), 2,710 m (403.9 mm), 3,070 m (523.3 mm), and 3,600 m (584.3 mm) above sea level of the Qilianshan Range.…”

Tectonically Controlled Establishment of Modern‐Like Precipitation Patterns in East and Central Asia During the Early Late Miocene

“…To test this, quantitative records of precipitation spanning at least the Middle and Late Miocene are crucial. However, quantitive precipitation records in Asia are generally scarce and have limitations, such as spanning only very short intervals (Gao et al., 2021; Miao et al., 2023), subject to equivocal interpretation (Jia et al., 2021; Nie et al., 2020), or limited to precipitation records reflecting only the East Asia summer monsoon (Hui & Liu, et al., 2023; Hui & Zhou, et al., 2021). In addition, most reconstructions of paleoprecipitation records are based on pollen data, and suitable material for interpretation is not available in all areas.…”