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In situ cosmogenic ^(10)Be, ^(26)Al, and ^(21)Ne dating in sediments from the Guizhou Plateau, southwest China

Science China Earth Sciences 2021年第8期64卷 1305-1317页

作者： Ye YANG Yu LIU Yan MA Sheng XU Cong-Qiang LIU Shi-Jie WANG Finlay M.STUART Derek FABEL Institute of Surface-Earth System Science School of Earth System ScienceTianjin UniversityTianjin 300072China Scottish Universities Environmental Research Centre East Kilbride G750QFUK State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China State Key Laboratory of Earthquake Dynamics Institute of GeologyChina Earthquake AdministrationBeijing 100029China

Landscape evolution is modulated by the regional tectonic uplift,climate change,and river ***,how to distinguish these mechanisms through the research of surface exhumation and fluvial incision remains *** this study,cosmogenic ^(10)Be,^(26)Al,and ^(21)Ne concentrations in quartz from cave deposits,modern river sediments,and bedrocks were measured to constrain the applicability of cosmogenic ^(21)Ne and discuss Quaternary landscape evolution history in the Guizhou Plateau,southeast *** the ^(26)Al-^(10)Be and ^(21)Ne-^(10)Be pairs to distinguish the cosmogenic ^(21)Ne concentration from the excess ^(21)Ne,we found that the nucleogenic ^(21)Ne produced by the U and Th decay in quartz is significant in the samples although there is the possibility of inherited cosmogenic ^(21)*** with previous studies,we suggest that the precise approach for applying the cosmogenic ^(21)Ne could be reached by(1)estimating the contribution from nucleogenic ^(21)Ne,(2)avoiding samples with complex burial histories to exclude inherited cosmogenic ^(21)Ne,and(3)combining the ^(10)Be-^(26)Al-^(21)Ne nuclides method for the Quaternary *** addition,both pre-burial basin denudation rates and burial ages derived from the ^(26)Al-^(10)Be pair were used to determine the different timescale surface denudation rate and fluvial incision rate in relation to previous *** consistency of the different timescales pre-burial basin denudation rate,^(36)Cl surface denudation rate,and modern basin denudation rate indicates that the landscape-scale surface denudation has been likely stabilized since the Quaternary in the Guizhou Plateau *** slightly higher river incision rates than the local surface denudation rate show that the river dynamics may not have reached a steady-state due to the regional tectonic uplift in the Guizhou Plateau.

关键词： Cosmogenic^(10)Be-^(26)Al-^(21)Ne Burial dating incision rate Landscape evolution Guizhou Plateau

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Tectonic and climatic controls for fluvial terraces of the Yellow River over the past 2.6 Ma at Northeast Tibetan Plateau and Ordos Block

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Journal of Mountain Science 2023年第8期20卷 2164-2180页

作者： GUO Xiao-hua FORMAN Steven WANG Yuan-yuan ZHANG Yu-feng LIU Xin-yu Qingdao Technical College QingdaoShandong 266555China Department of Geosciences Baylor UniversityOne Bear Place#97354WacoTX 76798USA

The Yellow River is usually assumed to record tectonic activities and climatic changes;however,a systematic study was lack in the sedimentology,stratigraphy,geomorphology and geochronology for the entire Yellow River though various geologic scholars have conducted numerous works in individual *** review focused on well-preserved fluvial terrace sequences that formed along this river on northeastern(NE)Tibetan Plateau and Ordos Block over the past 2.6 *** comparing numerous initial incision ages at different segments along the Yellow River,we found out that the youngest initial incision may occur at ca.150 ka at the Longyang *** Yellow River may transit from multiple separated endorheic drainages to an entire external drainage after 150 ka,which may cause differentiations in the apparent incision rates before and after 150 ka;thus apparent net incision rates were calculated respectively for the Yellow River before 150 ka and the drainage network post 150 *** net incision rates prior to 0.15 Ma were calculated as 0.15,0.29,0.10,0.12 and 0.03 mm/a respectively in Tongde-Xunhua,Lanzhou-Linxia basins,Heishan,Jinshan and Fenwei-Sanmen Gorges in this review,which mainly reflected Kunhuang-Gonghe Tectonic Event,generated by the Indo-Asian collision and diminishing as the NE Tibetan Plateau eastward extruding at ca.1.8-0.15 *** net incision rates post 0.15 Ma were calculated respectively for NE Tibetan Plateau and Ordos Block,considering their different base *** NE Tibetan Plateau,four fluvial degradational phases were identified between ca.105~70,53~40,25~16 and 12~6 ka associated with terrace levels respectively,at average elevations of 96,40,20 and 10.5 meters above the current river level(m arl)within a range of 5~96 m arl;and four broad periods in the last 150 ka on Ordos Block:possibly marine oxygen isotope stage(MIS)5,ca.118 to 72 ka,most of MIS 3,ca.44~28 ka,transition from LGM to last deglacial ca.20 to 16 ka,and 4~3 ka at ave

关键词： Yellow River Fluvial terraces Tibetan Plateau Ordos Block incision rate

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GIS and DEM based analysis of incision and drainage reorganization of the Buyuan River basin in the upper Lancang-Mekong of China since the Late Pleistocene

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Journal of Geographical Sciences 2020年第9期30卷 1495-1506页

作者： GU Zhenkui FAN Hui YANG Kun Yunnan Key Laboratory of In ternational Rivers and Tran sbo un dary Eco-Security Institute of International Rivers and Eco-SecurityYunnan UniversityKunming 650091China

River incision and drainage reorganization have an important impact on the site selection of many major projects including city,road and others,and are the key issues of Quaternary environmental *** of river incision and river-network adjustment have traditionally been based on extensive field evidence,such as sediment age and beheaded river *** Buyuan River basin is a large sub-basin of the upper Lancang-Mekong,with high mountains and extremely active *** latter affects the preservation of the Quaternary period sediments leading to difficulties in understanding the main evolution characteristics of the *** study investigates differences in the equilibrium state of the longitudinal profile,infers incision rates,and evaluates drainage divide migration timelines using the stream-power incision model,the latest morphological dating,and Chi-plots(χ–z) based on digital elevation models(DEMs) on the GIS software *** final results show that two significant erosion base-level decreases occurred in the Late Pleistocene at *** incision rate of the mainstream might have been 0–2.99 mm/yr since 100 ka BP and 0–3.28 mm/yr since 46 ka *** Chi-values across the divides suggest that space limited(or constrained) river reorganization and that there is no severe reorganization in the basin;the imbalance of traceable erosion only exists in local *** main driving force for the geomorphologic evolution of the Buyuan River basin is likely climate fluctuations rather than strong tectonic uplift since the Late Pleistocene.

关键词： incision rate river reorganization morphometric dating Buyuan River Lancang-Mekong

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