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Optically stimulated luminescence dating of aeolian sand in the Otindag dune field and Holocene climate change

Science China Earth Sciences 2008年第6期51卷 837-847页

作者： joseph mason James SWINEHART Ronald GOBLE Department of Geography University of Wisconsin Madison School of Natural Resources IANR University of Nebraska-Lincoln Department of Geosciences University of Nebraska-Lincoln

The dune system in Otindag sand field of northern China is sensitive to climate change, where effective moisture and related vegetation cover play a controlling role for dune activity and stability. Therefore, aeolian deposits may be an archive of past environmental changes, possibly at the millennial scale, but previous studies on this topic have rarely been reported. In this study, thirty-five optically stimulated luminescence (OSL) ages of ten representative sand-paleosol profiles in Otindag sand field are ob-tained, and these ages provide a relatively complete and well-dated chronology for wet and dry varia-tions in Holocene. The results indicate that widespread dune mobilization occurred from 9.9 to 8.2 ka, suggesting a dry early Holocene climate. The dunes were mainly stabilized between 8.0 and 2.7 ka, implying a relatively wet climate, although there were short-term penetrations of dune activity during this wet period. After ~2.3 ka, the region became dry again, as inferred from widespread dune activity. The '8.2 ka' cold event and the Little Ice Age climatic deterioration are detected on the basis of the dune records and OSL ages. During the Medieval Warm Period and the Sui-Tang Warm Period (570-770 AD), climate in Otindag sand field was relatively humid and the vegetation was denser, and the sand dunes were stabilized again. These aeolian records may indicate climate changes at millennial time scale during Holocene, and these climatic changes may be the teleconnection to the climate changes elsewhere in the world.

关键词： Otindag sand field OSL dating Holocene drought dune

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Sand dunes as potential sources of dust in northern China

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Science China Earth Sciences 2016年第4期59卷 760-769页

作者： Mark R SWEENEY LU HuaYu CUI MengChun joseph a mason FENG Han XU ZhiWei Department of Earth Sciences University of South Dakota Laboratory of Earth Surface Process and Environment School of Geographic and Oceanographic Sciences Nanjing University Department of Geography University of Wisconsin-Madison

While saltation bombardment of sand grains on a fine substrate can produce considerable dust, the well-sorted nature of sand dunes tends to preclude them from consideration as major dust sources. Recent research, however, has revealed that sand dunes can, in some cases, be large sources of dust. We used the PI-SWERL(Portable In-Situ Wind Erosion Laboratory) to measure in the field the potential of sand dunes and other desert landforms to emit particulate matter <10 μm(PM-10) dust in the Tengger, Ulan Buh, and Mu Us deserts of northern China. Combined with high resolution particle size measurements of the dune sand, an assessment of sand dunes as a dust source can be made. Large active transverse dunes tend to contain little to no stored PM-10, yet they produce a low dust flux. Coppice dunes stabilized by vegetation contain appreciable PM-10 and have very high dust emission potential. There is a positive correlation between the amount of PM-10 stored in a dune and its potential dust flux. Saltation liberates loose fines stored in dunes, making them very efficient dust emitters compared to landforms such as dry lake beds and washes where dust particles are unavailable for aeolian transport due to protective crusts or sediment cohesion. In cases where large dunes do not store PM-10 yet emit dust when active, two hypotheses can be considered:(1) iron-oxide grain coatings are removed during saltation, creating dust, and(2) sand grains collide during saltation, abrading grains to create dust. Observations reveal that iron oxide coatings are present on some dune sands. PI-SWERL data suggests that low dust fluxes from dunes containing no stored dust may represent an estimate for the amount of PM-10 dust produced by removal of iron oxide coatings. These results are similar to results from dunes in the United States. In addition, PI-SWERL results suggest that dust-bearing coppice dunes, which cover vast areas of China's sandy deserts, may become major sources of dust in the f

关键词： Coppice dunes Transverse dunes Dust PI-SWERL Desert

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High resolution particle siz e analysis as a tool for interpreting incipient soils in loess

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Chinese Science Bulletin 1999年第S1期44卷 70-74页

作者： joseph A. mason PeterM.JACOBS IConservation and Survey Division and Department of Geosciences University of Nebraska-Lincoln 113 Nebraska Hall Lincoln Nebraska 68588-0517 U.S.A. Department of Geography University of Wisconsin-Whitewater. 800 West Main Street. Whitewater Wisconsin 53190 U. S. A.

Thick loess deposits in the central U.S.A. often contain incipient soil zones that haveslightly darker color, more clay, and in most cases, stronger soil structure than surroundingunweathered loess. These incipient soil zones can be interpreted as the direct result of warmer orwetter climatic episodes, or as the sedimentary result of changes in local loess deposition ***-resolution particle size analyses by laser diffraction support a sedimentary explanation forincipient soil zones in Illinois and Nebraska, U.S.A. The soil zones contain more fine silt and claythan loess above and below. This could have resulted from a temporary reduction in the localloess deposition rate, leading to a greater relative contribution of far-traveled dust that containedmore fine silt and clay.

关键词： loess paleosols particle size analysis laser diffraction

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便携式粉尘观测仪测定腾格里沙漠和毛乌素沙地PM_(10)释放通量

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科学通报 2015年第17期60卷 1621-1630页

作者：崔梦淳鹿化煜 SWEENEY Mark mason joseph 冯晗徐志伟南京大学地理与海洋科学学院地貌过程与环境实验室南京210023 Department of Earth Sciences University of South Dakota Department of Geography University of Wisconsin

中国北方沙漠和沙地是亚洲粉尘释放的重要源区,定量估算这一地区的粉尘释放量有助于评估区域大气环境质量及其气候效应.目前,对中国北方粉尘释放量的估算主要是基于模拟结果,野外直接观测数据很少.利用一种新型的粉尘释放观测仪器——... 详细信息

中国北方沙漠和沙地是亚洲粉尘释放的重要源区,定量估算这一地区的粉尘释放量有助于评估区域大气环境质量及其气候效应.目前,对中国北方粉尘释放量的估算主要是基于模拟结果,野外直接观测数据很少.利用一种新型的粉尘释放观测仪器——便携式粉尘观测仪（PI-SWERL）,测量腾格里沙漠和毛乌素沙地若干典型地表（沙丘、干湖、灌丛沙丘、河流冲积物等）的粉尘释放通量,获得了不同地表潜在粉尘释放量的直接观测数据.结果表明,不同地表的PM10释放通量存在较大差异,但均随摩阻风速的增加而增加.在相同的摩阻风速U＊=0.55 m/s条件下,灌丛沙丘的PM10通量最高（0.70~10.23 mg/（m2 s））,河流冲积物次之（0.12~4.97 mg/（m2 s））,干湖湖底、沙丘等地表的通量较小（〈0.5 mg/（m2 s））.对比试验表明,破碎结壳地表释放的PM10通量是未破碎结壳的几倍甚至几十倍;披覆松散沙粒结壳地面的PM10释放通量高出未披覆的1~2个数量级.对比前人研究结果,PI-SWERL可以较好地反映不同源区粉尘释放的差异,对定量评估区域乃至全球的粉尘释放量等具有重要意义.

关键词：腾格里沙漠粉尘释放便携式粉尘观测仪(PI-SWERL) PM10通量摩阻风速

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Crescentic dune migration and stabilization： Implications for interpreting paleo-dune deposits as paleoenvironmental records

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Journal of Geographical Sciences 2017年第11期27卷 1341-1358页

作者： XU Zhiwei joseph A. mason LU Huayu YI Shuangwen ZHOU Yali WU Jiang HAN Zhiyong School of Geographic and Oceanographic Sciences Nanjing University Nanjing 210023 China Department of Geography University of Wisconsin Madison Wl 53706 USA School of Geography and Tourism Shaanxi Normal University Xi'an 710062 China

Paleo-dune deposits have been widely used as a proxy indicator of past dune ac- tivity, which is further used to reconstruct paleoclimates. However, recent studies have criti- cally examined the reproducibility of dune chronologies and the complexity of paleo-dune deposits as paleoenvironmental records. This paper addresses questions on the paleoenvi- ronmental implications of dune chronostratigraphies that have been raised by those reviews, in the specific case of crescentic dunes, using a case study from the Mu Us dune field, north-central China. The processes of turn-over and stabilization of relatively small crescentic dunes are first investigated by observational evidence. In combination with the analysis of a simplified sand preservation model and stratigraphic records, the effect of dune morphody- namics on sand preservation is demonstrated. It is especially evident that thick, nearly in- stantaneously deposited sand units record dune stabilization near the very end of a dune activity episode, while thin sand units may signal the preservation of sand deposited earlier in episodes of activity. Interpreting the distribution of luminescence ages that indicate sand deposition over time is not as simple as assumed in some previous work. Low frequency of sand ages could indicate an interval of either dune field stabilization or extensive dune activity but poor sand preservation. A peak of sand age frequency likely represents a shift in dune field activity towards stabilization, not a peak of active dune extent, especially if it partially overlaps with an independently identified interval of stabilization （e.g. one recorded by pa- leosols）. The nature and magnitude of these biases in the distribution of sand ages over time are strongly affected by the magnitude of net sand accumulation, which is in turn related to sand supply, transport capacity and sand availability, and ultimately climate change. Rela- tively short dune stabilization and turn-over time （101 to 102

关键词： dune activity dune chronologies dune morphodynamics dune turn-over time OSL dating paleoen- vironmental interpretation

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A preliminary quantitative reconstruction of precipitation in southern Mu Us sandy land at margin of Asian monsoon-dominated region during late Quaternary

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Journal of Geographical Sciences 2015年第3期25卷 301-310页

作者： CHEN Yingyong LU Huayu YI Shuangwen ZHANG Enlou XU Zhiwei YU Kaifeng joseph A. mason School of Geographic and Oceanographic Sciences Nanjing University Jiangsu Collaborative Innovation Center for Climate Change Nanjing 210023 China State Key Laboratory of lake Science and Environment Nanjing Institute of Geography and Limnology CAS Nanjing 210008 China Department of Geography University of Wisconsin Madison Wl 53706 USA

We present the first quantitative estimation of monsoon precipitation during the late glaciaI-Holocene in the sandy land of northern China, based on organic carbon isotopic composition data from a loess-sand sequence at margin of the Mu Us sandy land. We use the relationship between monsoon precipitation and the carbon isotopic composition of modern soils as an analogue, with a minor modification, to reconstruct precipitation back to c. 47 ka ago. The preliminary results indicate that annual monsoon precipitation was high after 8 ka, with an average of 435 mm; and it decreased during 18 and 8 ka with a mean value of 194 mm. The precipitation value of 47-18 ka varied between the two. We compare the recon- structed precipitation with other records and paleoclimatic modeling results, showing that our record agrees with reconstructions of the monsoon precipitation from other sources, even capturing short climatic events such as the Younger Dryas. We suggest that solar irradiance, high-latitude temperature/ice volume and local evaporation have together modified moistures in the sandy land.

关键词： quantitative reconstruction organic carbon isotopic composition precipitation Mu Us sandy land Asian monsoon

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中国北方沙漠-黄土体系的沉积和侵蚀过程与未来趋向探析

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地学前缘 2010年第5期17卷 336-344页

作者：鹿化煜李郎平弋双文王先彦 joseph A.mason 南京大学地理与海洋科学学院江苏南京210093 Department of Geography University of Wisconsin Madison

中国北方有大面积的土地被沙漠和黄土覆盖,是现代沉积和侵蚀比较活跃的地区。强烈的地表过程不仅影响着区域的生产生活活动,还通过粉尘传输影响北半球甚至于更大范围的气候和环境。长期以来,由于综合研究不够,对沙漠-黄土体系的沉积和... 详细信息

中国北方有大面积的土地被沙漠和黄土覆盖,是现代沉积和侵蚀比较活跃的地区。强烈的地表过程不仅影响着区域的生产生活活动,还通过粉尘传输影响北半球甚至于更大范围的气候和环境。长期以来,由于综合研究不够,对沙漠-黄土体系的沉积和侵蚀规律以及未来趋向的认识有限。结合对沙漠沙地-黄土沉积的高密度光释光年代测试结果,基于地统计法和遥感分析的黄土堆积量估算以及现代降尘、地表侵蚀的观察研究,认为沙漠沙地-黄土堆积区的沉积和侵蚀过程受气候变化控制,这里既是堆积区,又是侵蚀区,处于动态变化过程中;黄土比沙地沉积保存着更完整的过去气候变化信息。黄土高原水蚀和风蚀在地质历史时期就存在,人类活动加强了侵蚀过程,但可能还没有实质性地改变这一趋向。通过对地质记录和古气候模拟结果的分析,在未来全球变暖的背景下,沙地地区可能由于有效湿度减少变干而使风尘活动加强,黄土高原地区的粉尘沉积速率也将随之加快。

关键词：沙漠-黄土沉积沉积和侵蚀气候变化人类活动中国北方

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青海湖地区冰消期以来气候变化的黄土记录

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高校地质学报 2009年第1期15卷 135-140页

作者：赵存法鹿化煜周亚利弋双文 joseph mason 中国科学院地球环境研究所黄土与第四纪地质国家重点实验室西安710075 南京大学地理与海洋科学学院南京210093 Department of Geography University of Wisconsin MadisonWIUSA 53706 中国科学院研究生院北京100049

青海湖周围堆积着很多黄土和风沙沉积,这些风成沉积序列是过去气候变化的良好记录。相对于湖泊沉积,这些沉积物受到的研究较为薄弱。对青海湖南岸的黄土堆积进行了光释光年代学、磁化率、Fe/Mg值、粒度和有机质含量等气候替代性指标测... 详细信息

青海湖周围堆积着很多黄土和风沙沉积,这些风成沉积序列是过去气候变化的良好记录。相对于湖泊沉积,这些沉积物受到的研究较为薄弱。对青海湖南岸的黄土堆积进行了光释光年代学、磁化率、Fe/Mg值、粒度和有机质含量等气候替代性指标测量。在具有绝对年代标尺控制的基础上,结合气候替代性指标变化特征的分析,表明冰消期以来青海湖地区的古气候经历了多次的冷暖和干湿变化过程:14～9ka间气候前期相对冷干,后期转为凉干,其中可能在11ka左右存在一次暖湿事件;9～2.5ka间气候呈暖湿状态;2.5ka以后的地层扰动较大。黄土和湖泊沉积记录的环境变化过程具有可比性。

关键词：黄土冰消期环境变化青海湖地区

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Chinese deserts and sand fields in Last Glacial Maximum and Holocene Optimum

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Chinese Science Bulletin 2013年第23期58卷 2775-2783页

作者： LU HuaYu YI ShuangWen XU ZhiWei ZHOU YaLi ZENG Lin ZHU FangYing FENG Han DONG LiNa ZHUO HaiXin YU KaiFeng mason joseph WANG XiaoYong CHEN YingYong LU Qi WU Bo DONG ZhiBao QU JianJun WANG XunMing GUO ZhengTang School of Geographic and Oceanographic Sciences Institute for Climate and Global Change Research Nanjing University College of Tourism and Environment Shaanxi Normal University Department of Geography University of Wisconsin Madison Institute of Desertification Studies Chinese Academy of Forestry Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Institute of Geology and Geophysics Chinese Academy of Sciences

The Last Glacial Maximum (LGM, c. 26-16 ka) and the Holocene Optimum (HO, c. 9-5 ka) were characterized by cold-dry and warm-wet climates respectively in the recently geological Earth. How Chinese deserts and sand fields responded to these distinctive climatic changes is still not clear, however. To reconstruct environments of the deserts and sand fields during the LGM and HO is helpful to understand the forcing mechanisms of environment change in this arid region, and to test paleoclimatic modeling results. Through our long-term field and laboratory investigations, 400 optically stimulated luminescence (OSL) ages and more than 100 depositional records in the Chinese deserts and sand fields were obtained; on the basis of these data, we reconstruct spatial distributions of the deserts and sand fields during the LGM and HO. Our results show that the sand fields of Mu Us, Hunshandake, Horqin and Hulun Buir in northern and northeastern China had expanded 25%, 37%, 38% and 270%, respectively, during the LGM; the sand fields of Gonghe in the northeastern Qinghai-Tibetan Plateau had expanded 20%, and the deserts of Badain Jaran, Tengger in central northern China had expanded 39% and 29% separately during the LGM; the deserts of Taklimakan, Gurbantünggüt and Kumtag in northwestern China had expanded 10%-20% respectively, compared to their modern areas. On the other hand, all of the sand fields were nearly completely covered by vegetation during the HO; the deserts in northwestern and central northern China were reduced by around 5%-20% in area during this time. Lakes in this arid region were probably expanded during the HO but this conclusion needs more investigation. Compared with the geological distributions of deserts and sand fields, human activity has clearly changed (expanded) the area of active sand dunes at the present time. Our observations show that environmental conditions of Chinese deserts and sand fields are controlled by regional climate together with human a

关键词：沙漠环境中国北部适宜期全新世末次冰期末次盛冰期库姆塔格沙漠干旱地区

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EVOLUTION AND INTERACTION OFδ-WAVES IN THE ZERO-PRESSURE GAS DYNAMICS SYSTEM

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Acta Mathematica Scientia 2024年第5期44卷 1801-1836页

作者： Abhishek DAS K.T.joseph Centre for Data Science Institute of Technical Education and Research(ITER)Siksha‘O’Anusandhan(Deemed to be University)BhubaneswarOdisha751030India Centre for Applicable Mathematics Tata Institute of Fundamental ResearchSharada NagarBangalore560065KarnatakaIndia

Evolution and interaction of plane waves of the multidimensional zero-pressure gas dynamics system leads to the study of the corresponding one dimensional *** this paper,we study the initial value problem for one dimensional zero-pressure gas dynamics *** the first equation is the Burgers equation and the second one is the continuity *** consider the solution with initial data in the space of bounded Borel *** we prove a general existence result in the algebra of generalized functions of *** we study in detail special solutions withδ-measures as initial *** study interaction of waves originating from initial data concentrated on two point sources and interaction with classical shock/rarefaction *** gives an understanding of plane-wave interactions in the multidimensional *** use the vanishing viscosity method in our analysis as this gives the physical solution.

关键词： zero-pressure gas dynamics delta-waves interaction of waves

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