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The red clay and loess‐paleosol sediments of the Xiaoshuizi and Halagu planation surfaces of the northeastern Tibetan Plateau (TP) provide insights into the response of paleo‐atmospheric circulation and surface processes to TP uplift and global climate changes. We present silicate Sr‐Nd isotope compositions and bulk sediment grain‐size parameters of the red clay and loess‐paleosol sequences, with the aim of reconstructing changes in the transporting wind systems and sediment source regions. The results indicate that the red clay on the planation surface was transported mainly by the westerlies from the Tarim Basin and the Qilian Mountains, while the loess‐paleosol sediments were transported mainly by the East Asian winter monsoon (EAWM) from the Badain Jaran Desert, Tengger Desert, and Qaidam Basin. These shifts in transport mechanism and source were likely related to major changes in the topography of the TP and the expansion of Northern Hemisphere glaciation since the Middle Pliocene. In addition, we reconstructed the evolution of the paleo‐atmospheric circulation from the Late Miocene to the Middle Pliocene. During the Late Miocene, both the paleo‐EAWM and East Asian summer monsoon (EASM) were weak, and westerly winds dominated the climate of the study area. During the Early Pliocene, both the paleo‐EAWM and EASM exerted an increasing influence on the study area. We ascribe the slight enhancement of the paleo‐EAWM to the gradual growth of the northern TP and the significant enhancement of the paleo‐EASM to global climate changes. Key Points: A major transition in the sediment source and transport dynamic of eolian sediments on the NE TP occurred between the red clay and the overlying loess depositsFrom the Pliocene onward, the paleo‐EAWM and EASM were intensified and exerted an increasing influence on the XSZ planation surfaceThe contribution of the CAO to the XSZ red clay showed an increasing trend from the Late Miocene to the Middle Pliocene [ABSTRACT FROM AUTHOR]

The history of red clay‐loess accumulation in the Chinese Loess Plateau (CLP) is the key to understanding the aridification history of the Asian interior and the uplift of the Tibetan Plateau. Here we present high‐resolution magnetostratigraphy and grain‐size records of a 265.7‐m‐long drill core of the red clay‐loess sequence at Gaolanshan in the Lanzhou Basin from the western CLP. Our results, combined with the loess‐paleosol stratigraphy and regional stratigraphic correlation, indicate that the most complete and continuous red clay‐loess sequence since ~3 Ma was first found in the western CLP, which is ~0.8 Myr older than the previously investigated Quaternary loess in the Lanzhou region, and the age of the oldest Lanzhou loess‐paleosol sequence is ~2.8 Ma. Consequently, the major enhancement of the aridification at 2.8 Ma in the Asian interior was primarily controlled by the uplift of the Tibetan Plateau and global cooling. Plain Language Summary: The deposition of eolian loess in the Chinese Loess Plateau provides critical information for understanding the aridification history of the Asian interior and the uplift of the Tibetan Plateau. However, eolian deposits in the Lanzhou Basin of the western Chinese Loess Plateau dated to the interval of 3.6–2.2 Ma have rarely been studied, which hinders our understanding of the process of regional aridification and the history of tectonic activity. High‐resolution magnetostratigraphy, grain‐size records, loess‐paleosol stratigraphy, and regional stratigraphic correlation suggest that the basal age of the Gaolanshan drill core is ~3 Ma, which is some 0.8 Myr older than the previously investigated Quaternary loess in the Lanzhou region. The age of the base of the typical loess‐paleosol deposits in the Lanzhou area is ~2.8 Ma. A synthesis of other eolian sections reveals that the Lanzhou loess is one of the most complete and continuous continental sedimentary archives for reconstructing climatic evolution since the Late Pliocene. Pronounced increases in grain size and sedimentation rate in loess layer L34 indicate an enhancement of aridity at 2.8 Ma in the Asian interior, and we conclude that this event was likely driven by both tectonic activity and global cooling. Key Points: The red clay‐loess sequence since ~3 Ma was first found in the Lanzhou Basin, western Chinese Loess PlateauThe pronounced increase in grain‐size and sedimentation rate at 2.8 Ma supported the intensified aridification in the Asian interiorThis obvious aridification was primarily caused by the uplift of the Tibetan Plateau and global cooling [ABSTRACT FROM AUTHOR]

In the east of Xiaolangdi, many river terraces are developed at the exit of the Yellow River Gorges. Among them the terraces in Kouma, Yanshi of Henan Province are most typical, where the Yellow River developed three staircase terraces, among which the altitude of gravel stratum of the topmost terrace is 30-35 m higher than the river level. The top of the gravel stratum was covered by 60 m eolian loess deposits which have many brownish-red paleosol strips. And the paleosol S14 is at its bottom. Research on systematic magnetostratigraphy and paleosol-loess matching indicates that the bottom age of the loess on the topmost terrace is 1165 ka. Therefore, it can be concluded that the terrace develops no later than 1.165 Ma and the situation that the Yellow River runs through Sanmen Gorges and inpours into East China Sea happened at least before 1.165 Ma. [ABSTRACT FROM AUTHOR]

Whether climatic changes in high latitudes of the Northern Hemisphere since the last glaciation have effects on the Tibetan Plateau monsoon, and the variation characteristics of the Plateau monsoon itself are still not solved but of great significance. The 22-m high-resolution loess-paleosol sequence in the Hezuo Basin on the northeastern Tibetan Plateau demonstrates that the Plateau winter monsoon experienced a millennial variation similar to high latitude Northern Hemisphere, with cold events clearly correlated with Heinrich events but less for the warm events (Dansgarrd-Oeschger events). It may indicate that the climate system at high latitudes in the Northern Hemisphere had played an important role in both the Plateau monsoon and the high-level westerlies. On 104 year scale, there are two distinct anomalous changes, which are not found in the records from high latitude northern hemisphere, revealed by the loess grain size in the Hezuo Basin. One is that there was a considerable grain size increase at ∼36 kaBP, suggesting an abrupt enhancement of the Plateau winter monsoon at that time; the other is that, during 43-36 kaBP, the grain size decreased distinctly, indicating a notable weakening of the Plateau winter monsoon around that period. Both of the two anomalies suggest that the Tibetan climate may have been controlled by some other factors, besides the high latitude climatic changes in the Northern Hemisphere. [ABSTRACT FROM AUTHOR]

A 1.5 Ma sporopollen record was obtained from a continuous loess-paleosol sequence at Chaona in the central Chinese Loess Plateau. It shows that (1) arid herbs of largely Artemisia and Chenopodiaceae and arbors of mainly Pinus, Betula and Quercus dominate loess and paleosol, respectively, reflecting cycles of cold-dry and warm-humid conditions of glaciation and interglaciation; (2) that similar vegetation pattern and cold-dry condition were found in times of unusual thick and coarse loesses L9 and L15, which have been regarded as two extremely cold and dry times as indicated by inorganic climatic proxies; and (3) that shifts of vegetations from earlier forest-steppe to open-forest and steppe and then to steppe were found at 0.95 and 0.5 Ma, implying a stepwise of drying of the Loess Plateau in the Quaternary. [ABSTRACT FROM AUTHOR]

Focuses on eolian loess that was distributed on geomorphic surfaces on the northern slope of the Tian Shan. Formation in a synchronous manner with dust from the Gurbantunggut Desert in the Junggar Basin; Thickness of the loess section in the Shawan and Shihezi regions; Paleomagnetic and climatic proxy analyses on the highest terrace of the Qingshui He (River) in the Shawan; Finding that the paleomagnetic Bruhues/Matuyama (B/M) boundary lies at the bottom of paleosol S8, at a depth of 69.5 m; Suggestion that the climatic conditions in the basin and the desert were present by 0.8 Ma; High-resolution grain size series showing two periods of desert expansion; Implication of this large-scale expansion of arid regions in inner Asia for the global temperature drop that occurred in the mid-Pleistocene.

The soil color is widely used in paleoclimate and paleoenvironment reconstructions in the Chinese Loess Plateau. To better understand the color spatial changes during the glacial–interglacial cycle, the soil color lightness ( L * ), characteristic spectra, magnetic susceptibilities and mean grain sizes of three loess–paleosol sequences were compared. Results showed that high L * and low hematite to goethite ratios (Hm/Gt) appeared in loess units, and low L * and high Hm/Gt ratios accompanied paleosol layers, indicating glacial–interglacial hydrothermal oscillation. L * in the Yulin section was higher than in the Chaona and Lihuacun sections, indicating that different precipitations have great effect on L * . Furthermore, Hm/Gt, magnetic susceptibility ( χ lf ), and mean grain size are correlated closely with L * . L * and Hm/Gt not only document climatic variations in the glacial–interglacial cycle vis - à - vis loess–paleosol sequences, but also can identify Heinrich cold events and millennial scale Dansgaard–Oeschger (D–O) warm events. It suggests that soil color responds sensitively to global climate change driven by ice volumes. L * and Hm/Gt curves exhibit higher frequencies and larger amplitudes than magnetic susceptibility ( χ lf ) curves, indicating that L * and Hm/Gt can be regarded as sensitive and reliable proxies for characterizing high-resolution climate change during the last glacial–interglacial cycle. [ABSTRACT FROM AUTHOR]

Analysis of morphological properties in the San men Gorges region of the Yellow River shows that four river terraces have been developed at the entrance to the gorges. Commonly, thick aeolian loess-paleosol sequence was deposited on the terraces, which makes it easy to date the terraces. The dating of paleomagnetic, loess-paleosol sequence matching and thermoluminescence show that terraces T2, T3 and T4 were formed 0.129 Ma, 0.625 Ma and 0.865 Ma ago, respectively. The formation of these terraces in this region indicates that the Yellow River has experienced four intensive downcutting events during the last 0.9 Ma. The Yellow River cut through the Sanmen Gorges and inpoured into the East China Sea no later than 0.865 Ma. [ABSTRACT FROM AUTHOR]