| 1. |
- Buylaert, Jan-Pieter, et al.
(författare)
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A detailed post-IR IRSL chronology for the last interglacial soil at the Jingbian loess site (northern China)
- 2015
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Ingår i: Quaternary Geochronology. - : Elsevier BV. - 1871-1014 .- 1878-0350. ; 30, s. 194-199
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Tidskriftsartikel (refereegranskat)abstract
- The chronology of dust deposition and climate during the last interglacial is poorly known on the Chinese Loess Plateau. Here, 51 samples were taken from the similar to 5 m S1 palaeosol (MIS5) at the desert marginal Jingbian site to develop what is currently the most detailed S1 chronology on the Plateau using instrumental dating techniques. We use the post-IR IRSL signal from sand-sized grains of K-rich feldspar. Signal resetting in the agricultural layer shows that it is possible to almost completely zero this signal in nature. First IR stimulation plateau measurements show that there is no clear dependence of D-e on first IR stimulation temperature between 50 and 260 degrees C suggesting negligible signal fading. Resultant ages are consistent with a last interglacial age (similar to 130 to similar to 75 ka) and are also consistent within errors with continuous linear sedimentation rates. The average mass accumulation rate for S1 is similar to 150 g m(-2) a(-1), considerably higher than at many other sites but within the overall range of Loess Plateau estimates. The remarkably stable sediment accumulation at the site contrasts with a more complex record of environmental and monsoonal change recorded in grain-size and magnetic susceptibility.
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| 2. |
- Hou, Yandong, et al.
(författare)
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Sahara's surface transformation forced an abrupt hydroclimate decline and Neolithic culture transition in northern China
- 2024
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Ingår i: The Innovation. - 2666-6758. ; 5:1
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Tidskriftsartikel (refereegranskat)abstract
- The remote forcing from land surface changes in the Sahara is hypothesized to play a pivotal role in modulating the intensity of the East Asian summer monsoon (EASM) through ocean-atmospheric teleconnections. This modu-lation has far-reaching consequences, particularly in facilitating societal shifts documented in northern China. Here, we present a well-dated lake-level record from the Daihai Lake Basin in northern China, providing quantitative assessments of Holocene monsoonal precipitation and the consequent mi-grations of the northern boundary of the EASM. Our reconstruction, informed by a water-and-energy balance model, indicates that annual precipitation reached -700 mm during 8-5 ka, followed by a rapid decline to -550 mm be-tween 5 and 4 ka. This shift coherently aligns with a significant -300 km northwestward movement of the EASM northern boundary during the Middle Holocene (MH), in contrast to its current position. Our findings underscore that these changes cannot be entirely attributed to orbital forcing, as corrob-orated by simulation tests. Climate model simulations deployed in our study suggest that the presence of the Green Sahara during the MH significantly strengthened the EASM and led to a northward shift of the monsoon rainfall belt. Conversely, the Sahara's reversion to a desert landscape in the late Ho-locene was accompanied by a corresponding southward retraction of monsoon influence. These dramatic hydroclimate changes during -5-4 ka likely triggered or at least contributed to a shift in Neolithic cultures and societal transformation in northern China. With decreasing agricultural pro-ductivity, communities transitioned from millet farming to a mixed rainfed agriculture and animal husbandry system. Thus, our findings elucidate not only the variability of the EASM but also the profound implications of a remote forcing, such as surface transformations of the Sahara, on climatic changes and cultural evolution in northern China.
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| 3. |
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| 4. |
- Peric, Zoran, et al.
(författare)
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Quartz OSL dating of late quaternary Chinese and Serbian loess : A cross Eurasian comparison of dust mass accumulation rates
- 2019
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Ingår i: Quaternary International. - : Elsevier BV. - 1040-6182 .- 1873-4553. ; 502:Part A, s. 30-44
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Tidskriftsartikel (refereegranskat)abstract
- Reconstructing dust Mass Accumulation Rate (MAR) from loess deposits is critical to understanding past atmospheric mineral dust activity and requires accurate independent age models from loess deposits across Europe and Asia. Previous correlations of loess in Europe and China have tended to focus on multi-millennial timescales, with no detailed examination of dust MAR at the two ends of the Eurasian loess belt on shorter, sub-orbital scales. Here we present a detailed quartz optically stimulated luminescence (OSL) chronology from the Serbian Titel Loess Plateau (Veliki Surduk loess core) and the Chinese Loess Plateau (Lingtai section). The luminescence ages pass internal tests and show consistent increases in age with depth, with no obvious major hiatuses. However, as reported before, it seems the quartz OSL technique is only capable of accurate age determination up to accrued doses of ca. 150 Gy (ca. 30–40 ka) due to approaching field saturation of the quartz OSL signal. Two age-depth models were used to reconstruct dust MARs, where one utilises OSL data solely and the other additionally makes assumptions about sedimentation rates. Although short-term fluctuations in MAR are model dependent, general MAR patterns between the two sites are very similar, with peak MAR occurring rather late in the last glacial (ca. 13–25 ka). This suggests that at least broad scale trends in dust activity within the last glacial period may be similar at a continental scale.
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| 5. |
- Stevens, Thomas, 1979-, et al.
(författare)
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Ice-volume-forced erosion of the Chinese Loess Plateau global Quaternary stratotype site
- 2018
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The International Commission on Stratigraphy (ICS) utilises benchmark chronostratigraphies to divide geologic time. The reliability of these records is fundamental to understand past global change. Here we use the most detailed luminescence dating age model yet published to show that the ICS chronology for the Quaternary terrestrial type section at Jingbian, desert marginal Chinese Loess Plateau, is inaccurate. There are large hiatuses and depositional changes expressed across a dynamic gully landform at the site, which demonstrates rapid environmental shifts at the East Asian desert margin. We propose a new independent age model and reconstruct monsoon climate and desert expansion/contraction for the last ~250 ka. Our record demonstrates the dominant influence of ice volume on desert expansion, dust dynamics and sediment preservation, and further shows that East Asian Summer Monsoon (EASM) variation closely matches that of ice volume, but lags insolation by ~5 ka. These observations show that the EASM at the monsoon margin does not respond directly to precessional forcing.
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| 6. |
- Stevens, Thomas, 1979-, et al.
(författare)
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Mass accumulation rate and monsoon records from Xifeng, Chinese Loess Plateau, based on a luminescence age model
- 2016
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Ingår i: Journal of Quaternary Science. - : Wiley. - 0267-8179 .- 1099-1417. ; 31, s. 391-405
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Tidskriftsartikel (refereegranskat)abstract
- Luminescence dating of loess accumulation in China has raised questions over disturbance and gaps in the record, the magnitude of mass accumulation rates (MARs), and monsoon forcing mechanisms. Here we present a detailed quartz optically stimulated luminescence (OSL) chronology from the Xifeng Chinese Loess Plateau site. We reconstruct MARs and construct an age model for monsoon proxies at the site. The luminescence ages show significant pedogenic and anthropogenic disturbance in material deposited after ca. 20-22 ka. Analysis of other published data suggests that this disturbance may be more common than previously realized. MARs from undisturbed portions of Xifeng vary dramatically, with peaks potentially matching the timing of Heinrich events. The last glacial maximum peak MAR (22-27 ka) matches the Pacific and Greenland dust flux records, although appears earlier than peak MARs seen in many other OSL-dated Loess Plateau sites. East Asian monsoon grain-size and magnetic susceptibility records also show several differences between independently dated loess sites. This complicates our understanding of any lag between insolation forcing and monsoon response. Nevertheless, the Xifeng climate proxy changes show apparent broad agreement with the timing of Heinrich events in the North Atlantic, supporting assertions of a climatic teleconnection between the two areas.
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