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Abstract: The key to understanding the fluvial response to climate change and surface uplift is a thorough distinguishing between their roles in terrace formation. Previous studies have tended to attribute the fluvial behavior of deposit–incision alternation to climate cyclicity. A preliminary explanation is proposed here for terrace formation in the eastern part of the Fenwei Basin, China. The observed fluvial terrace sequence was developed by the Yellow River deeply downcutting into the Emei Platform, which was uplifted within the eastern Fenwei Basin, and therefore it probably records the tectonic history of this platform. On the basis of the magnetostratigraphy and optically stimulated luminescence (OSL) dating, a ca. 1.2Ma chronology was established for this terrace sequence. Pedostratigraphic analysis of the loess deposits accumulated on each tread reveals that the terrace deposits are overlain immediately by a paleosol bed, suggesting that the abandonment of these terraces due to fluvial incision occurred at the transitions from glacial to interglacial climates. The glacial–interglacial climate cycle probably has a temporal control on the fluvial behavior of deposit–incision alternation, even though the Yellow River develops in the subsiding Fenwei Basin. The terrace generation may be sporadic and in the form of unusual stacked pattern before the Emei Platform was uplifted within the eastern Fenwei Basin. The terrace staircases however, formed in synchrony with glacial–interglacial climate cycles since this platform began to uplift in the late Middle Pleistocene. This result indicates that uplift may be necessary in large terrace staircase genesis. It can force the river system to downcut deeply enough during climatic transitions to separate terrace levels adequately, favoring the generation and subsequent preservation of the terrace treads. The terrace sequence of the Yellow River in the eastern Fenwei Basin therefore can be considered as a combined archive of climate change and local tectonic activity. [Copyright &y& Elsevier]

Abstract: A continuous fluviolacustrine record provides the geochronological framework to reconstruct the fluvial landscape evolution of the middle reach of the Huanghe (Yellow River). Magnetostratigraphic records from six sections at the north of the Jinshaan Gorge indicate that an isolated fluviolacustrine system occupied this gorge from 8.3 to 3.7Ma. Local fluvial incision initiated at the lake margin around 5.3-4.9Ma, and concomitant fluvial deposits intruded laterally into fine lacustrine strata increasing the sedimentation rate (ca. 3.1cm/ky) within the isolated lake. The temporal coincidence of the onset of uplift-driven valley incision at 3.7Ma along the Yellow River and the onset of basin excavation suggest that uplift possibly played an important role in the late Pliocene-Quaternary drainage evolution. Consequently, incision of the Yellow River upstream in the Jinshaan Gorge initiated at 3.7Ma. [Copyright &y& Elsevier]

The Jinsha River has attracted considerable attention for nearly a century due to the morphology of its drainage basin. To explain the evolution of the Jinsha drainage basin, most researchers have considered that the present-day Jinsha (the upper reach of the Yangtze) was once a tributary of a single, southward-flowing river system called the Paleo-Red River, which drained into the South China Sea and was captured by the Upper Yangtze River, after which the flow direction changed to eastwards. The sudden disappearance, at 5.5 Ma, of the Red River submarine fan, which was fed primarily by the Paleo-Red River system, provides an important chronological constraint on the drainage reorganization and the capture event. However, until now, no geomorphic evidence has been presented to support this hypothesized age. Considering this problem, nine well-preserved terraces (T9 to T1) at Jinjiangjie in the Middle Jinsha River were evaluated in this study. To establish the chronological framework of these terraces, a combined dating approach was employed, incorporating electron spin resonance dating, cosmogenic nuclide (26Al/10Be) burial dating, and optically stimulated luminescence dating. We obtained a complete chronological sequence for terraces T9–T1, with ages of approximately 1.07 (T9), 0.70 (T8), 0.65 (T7), 0.51 (T6), 0.47(T5), 0.44(T4), 0.30 (T3), 0.18 (T2), and 0.047 (T1) Ma, respectively. Constrained by this framework, we calculated an average long-term fluvial incision rate of ~147 mm/ka. The reconstruction of the paleo-topography and paleo-drainage, based on digital elevation model data for the re-filling of the deeply incised river valley, indicates that the present drainage pattern in the Middle Jinsha system was established after the disruption of the paleo-landscape surface at an elevation of ~2000 m above sea level. The age of the present-day Middle Jinsha drainage was determined at approximately 5.5 Ma by extrapolating the average valley incision rate, suggesting that the present-day Jinsha was formed at about this time. Our results agree with the previously estimated timing of the disappearance of the Red River submarine fan. • A flight of 9 fluvial terraces dated using ESR, 26Al/10Be and OSL dating in Jinsha River (the upper reach of Yangtze) • About 147 mm/ka of average incision rate in Middle Jinsha River since early Pleistocene • First age of Jinsha River achieving its present-day drainage pattern extrapolated from the average valley incision rate [ABSTRACT FROM AUTHOR]

[Display omitted] • The terrace sequences of Datong River were dated using multiple dating methods. • Tectonic-climate forcing triggered the formation of the Datong River before ∼1.1 Ma. • The Datong River has been more sensitive to climate changes than the Yellow River. The formation of river terraces has been related to climate changes and surface uplift in the mountain regions. Although the formation mechanism of river terraces in the northeastern Tibetan Plateau has been extensively studied, the difference between the large river (trunk stream of Yellow River) and small rivers (tributaries of Yellow River) responding to external forcing is still poorly understood. Here, we employ multiple dating methods to date the terrace sequence of the Datong River in the northeastern Tibetan Plateau and then further correlate it with tectonic activity and climate records. Our results show that the modern Datong River in the Babaochuan Basin formed between 1.5 Ma and 1.1 Ma in response to the coupled effects of Asian monsoon enhancement and intense regional uplift. To further evaluate the effect of tectonic–climatic forcing on rivers of different scales, detailed comparison of terrace formation was carried out between the Datong River and Yellow River in the Lanzhou Basin. The comparison results indicate that under the context of relatively slow surface uplift during 0.6–0.13 Ma, the Datong River created three terraces probably ascribed to the glacial–interglacial cycles with high-amplitude fluctuations, whereas no terraces formed along the Yellow River in the Lanzhou Basin during the same interval. We conclude that the Datong River, as a smaller river than the trunk Yellow River, is probably more sensitive to the climate change. [ABSTRACT FROM AUTHOR]