Figure 4. Variations are shown in the percentages of <4 μm, 4–32 μm, 32–63 μm, and >63 μm grain-size fractions and median grain sizes from the Yaodian section (Tianshui Basin). The stratigraphic age of the Yaodian section is derived from astronomical timescale work of Wang et al. (2019

Figure 8. Summary shows spectral analysis results from the Yaodian section in the Tianshui Basin and the Jiarang section in the Jianzha Basin and comparison with other climate records over the interval 10.25–8 Ma. (A) Theoretical eccentricity, tilt, and precession curve for the interval 10.25–8

Figure 6. Triangular diagrams and principal component analysis (PCA) biplots for transparent heavy-mineral data of the Tianshui Basin, Central Asia, Miocene silts compared to samples from: (A) the latest Miocene–Quaternary loess/Red Clay and potential sources (modern rivers and deserts) and (B

Figure 8. Multi-dimensional scaling (MDS) maps for the individual U-Pb age data of the Tianshui Basin, Central Asia, silts compared to samples from: (A) the Yellow River, West Qinling and other mountain ranges; (B) eolian dunes and surficial sands from deserts and drylands; (C) latest Oligocene

Figure 3. 87 Sr/ 86 Sr variations in water and acetic acid leachates along the Heilinding section in Linxia Basin and the Lamashan section in Tianshui Basin. GPTS—geomagnetic polarity time scale ( Gradstein et al., 2012 ).

Figure 3. Fe oxides/transparent/phyllosilicate heavy-mineral triangular diagrams for samples from the Tianshui Basin and West Qinling Mountains of Central Asia. (A) sand fraction of samples from the source area to the basin. (B) comparing sand and silt fractions among each pair of subsamples. (C

Figure 4. Heavy-mineral assemblages of the silt and sand samples from the Tianshui Basin, and the loess/Red Clay samples from the Chinese Loess Plateau, Central Asia. (A) Time-series volume percentage of transparent heavy minerals of the studied sections. The data of Lingtai section are from

rank series ( Yao et al., 2022 ). (E) Late Miocene section in Tianshui Basin exhibiting dominant 100 k.y. cycles in the magnetic susceptibility series ( Wang et al., 2019 ).

Figure 2. (A) Lithology and magnetic stratigraphy of the Yaodian section, Tianshui Basin, are shown (from Li et al., 2006 ; and Liu et al., 2016 ). GTS2020 is the astronomically tuned Neogene time scale ( Gradstein et al., 2020 ). (B) Magnetic susceptibility (MS, from Wang et al., 2019

basin ( Horton et al., 2004 ; Dai et al., 2006 ; Zhang et al., 2017 ; Yang et al., 2017 ; Fang et al., 2019 ), Lanzhou basin ( Wang et al., 2016a ), Xunhua basin ( Lease et al., 2012 ; Liu et al., 2013 ), Linxia basin ( Fang et al., 2003 , 2016 ), Tianshui basin ( Wang et al., 2012b ; Xiong, 2017

Miocene Climate Cooling. a – magnetic susceptibility record of the HTG section in the Qaidam Basin (Guan et al. 2019 ); b – percentages of the pollen of xerophytic taxa from core KC-1 from the Qaidam Basin (Miao et al. 2011 ); c – tree pollen percentages from the Yanwan section in the Tianshui Basin

Figure 5. Kernel density estimators (KDEs) spectra and main components for detrital zircon U-Pb ages of samples from the Tianshui Basin and Chinese Loess Plateau, Central Asia, shown for the interval 0–2600 Ma. For the n/N, N is the total number of analyzed grains and n is the number

that there is no proprietary data for the Paleogene terrane on the West Qinling Mountains, we employed the sample YDE to represent the source unit as it is consistent with the common feature of regional Paleogene sediments ( Liu et al., 2015 ). (B) Dissimilarity (D value) and P value (probability value) to the Tianshui Basin

Figure 1. Map shows the Tianshui and Jianzha Basins and sampling locations. Faults are from Wang et al. (2019) . EAWM—East Asian winter monsoon; EASM—East Asian summer monsoon.