中国北方沙漠由12个主要沙漠/沙地组成，是全球沙漠的重要组成部分，也是全球粉尘释放的重要源地。多年来有关我国北方沙漠沉积物特征及其空间差异的系统性研究相对薄弱，影响了人们对中国北方沙漠现代沉积、风化和风沙环境的系统认识。本文系统采集了中国北方沙漠1574个样点的表层沉积物样品，通过沉积物粒度、颗粒形貌、化学元素、矿物、有机质和养分含量测定，分析了各理化性质指标的分布特征及其反映的沉积环境，阐明了各沙漠之间的物源成因相似性。这些研究对全面了解沙漠表层沉积物特征，深入认识沙漠现代沉积、风化和风沙环境及其区域差异，探析沙漠之间的物源成因相似性具有重要的科学意义；对深入理解“亚洲风成系统”演化，尤其是粉尘沉积的物源示踪以及过去大气环流形势变化的重建具有重要的参考价值；为沙区经济建设提供系统的基础资料。论文在以下几个方面取得进展：

（1）沉积物粒度特征。中国北方沙漠表层沉积物优势粒级为中沙（31.5%）和细沙（40.4%），黏粒和极粗沙含量极低，平均粒径为2.34Φ，总体中等分选。西部沙区（包括古尔班通古特沙漠、塔克拉玛干沙漠、库姆塔格沙漠和柴达木盆地沙漠）和中部沙区（巴丹吉林沙漠、腾格里沙漠、乌兰布和沙漠、库布齐沙漠和毛乌素沙地）表层沉积物平均粒径细颗粒含量较低而粗颗粒含量较高，分选较好，粒度分布呈近对称。东部沙区（包括浑善达克沙地、科尔沁沙地和呼伦贝尔沙地）表层沉积物颗粒较细，分选较差，粒度频率分布曲线正偏，峰态较窄。

（2）沉积物颗粒形貌特征。中国北方沙漠表层沉积物颗粒磨圆度较差，以次棱角状和次圆状居多，棱角状和圆状颗粒很少，各沙漠下风向区域颗粒磨圆度优于上风向区域；东部沙区磨圆度优于西部沙区和中部沙区。麻坑/麻面出现频率最高，其次是碟形坑和水下磨光面；石英颗粒表面显微特征中风成作用突出，流水作用和冰川次之，化学溶蚀作用弱。西部沙区石英表面机械作用大于化学作用，东部沙区相反，中部沙区介于二者之间。

（3）沉积物元素地球化学特征。中国北方沙漠表层沉积物元素地球化学分布存在明显的区域性和规律性。其中，常量元素SiO₂自西向东逐渐增多，其它常量元素趋于减少；微量元素Co和Cr西低东高，Cu、Ga、Hf、Ni相反，其余微量元素无明显变化趋势；各常量元素和微量元素亏损程度由高到低依次为东部沙区、中部沙区和西部沙区。

（4）沉积物矿物特征。中国北方沙漠表层沉积物中，轻矿物总含量西低东高，以石英和长石类矿物为主；重矿物总含量西高东低，以角闪石、帘石类、石榴子石类和铁矿石类矿物为主。轻矿物成熟度平均值为1.76，重矿物风化系数、ZTR指数、ATi指数和GZi指数平均值分别为1.71、5.49、44.60和91.84，东部沙区矿物成熟度高于中部和西部沙区。

（5）沉积物有机质和养分特征。中国北方沙漠表层沉积物有机质、全N、全P和全K含量处于较低水平，平均值分别为0.32%、0.18 g kg^-1、0.17 g kg^-1和17.85 g kg^-1。有机质和全N含量自西向东呈增加趋势，全P含量变化趋势相反，全K含量在东部沙区和西部沙区较高，在中部沙区较低。有机质和全N含量与干燥度空间分布格局相似，全P和全K含量空间分布受母质影响较大。

（6）表层沉积物理化特征空间差异及其与现代风沙环境的关系。中国北方沙漠表层沉积物粒度组成、颗粒形貌特征、元素地球化学含量、矿物含量、有机质和养分含量分布是气候条件、风沙环境和植被覆盖综合作用的结果。东部沙区气候相对湿润，植被覆盖度高，是沙漠表层沉积物细颗粒含量高、分选性差、粒度频率分布曲线正偏、峰态窄、颗粒表面化学成因特征出现频率高、不稳定元素和矿物淋失严重与有机质和全N含量高的重要原因。西部沙区和中部沙区细颗粒大量损失而粗沙和极粗沙含量较高，分选性较好，颗粒表面化学成因特征出现频率低，元素和矿物亏损较少，有机质和养分含量大量流失，反映了干燥气候条件下植被覆盖度低、风沙活动强烈的风沙环境。

（7）沉积物理化特征反映的沉积环境。塔克拉玛干沙漠和库姆塔格沙漠颗粒表面形态冰川成因作用出现的频率较高，遭受物理风化作用较强，说明沉积物经历了寒冷干燥的沉积环境和活跃的风沙活动。而古尔班通古特沙漠、毛乌素沙地、浑善达克沙地、科尔沁沙地和呼伦贝尔沙地颗粒表面形态化学成因作用和流水成因作用明显，水下磨光面、擦痕和刻痕出现频率高，遭受物理风化作用较弱，印证了这些沙漠较湿润的沉积环境。沉积物表面形态、元素、矿物特征，以及各沙漠合成输沙方向，反映了西部沙区的表层沉积物与中部沙区的表层沉积物物源成因相似度较高，而与东部沙区物源成因相似度较低。

The Northern Chinese deserts, consisting of 12 major deserts, are an important part of the global deserts and a source of global dust emission. Due to the lack of systematic and complete information on the physicochemical properties of desert surface sediments, the comprehensive understanding of modern deposition, weathering and aeolian environment in the Northern Chinese deserts has been affected. This paper systematically collected surface sediment samples from 1574 sample sites in the Northern Chinese deserts. We analyzed the distribution characteristics of each physicochemical feature and its reflective depositional environment by measuring the surface sediment grain size, particle micro-morphology, elemental geochemistry, mineral, organic matter and nutrient contents, and clarified the similarity of the source origin among deserts. These studies not only help to comprehensively understand the characteristics of desert surface sediments, deeply recognize the modern deposition, weathering and aeolian environment of deserts and its regional differences, and explore the similarity of materials source origin among deserts with important scientific significance, but also provide systematic basic information for the economic construction of sand areas. The paper makes progress in the following aspects:

(1) Characteristics of sediment grain size. The surface sediment of Northern Chinese deserts has a wide range of grain size distribution, dominated by medium and fine sands, with little clay, coarse and very coarse sand. The mean grain size was 2.34Φ, and the sortability was moderately sorted, with a positively skewed grain size frequency distribution curve and a narrow peak-shaped distribution. The surface sediment in the Western deserts (including Taklimakan, Gurbanttgut, Kumtag and Qaidam Basin deserts) and Central deserts (including Badain Jaran, Tengger, Ulan Buh and Hobq deserts, and Mu Us sandy land) has a low content of clay and a high content of coarser sands, with good size sortability ana nearly symmetrical distribution of the size frequency distribution curve. In contrast, the surface sediment in the Eastern deserts (including Otindag, Horqin and Hulun Buir sandy lands) is finer, with a positive skew and narrower kurtosis.

(2) Characteristics of sediment particle morphology. The surface sediment particles of the Northern Chinese deserts are poorly rounded, mostly sub-angular and sub-rounded, with few angular and rounded particles; the rounding of particles in the downwind areas of the deserts is better than that in the upwind areas; the rounding is better in the Eastern deserts than in the Western and Central deserts. The frequency of pockmarked/pockmarked surface is the highest, followed by disc-shaped pockmark and underwater polished surface. The quartz surface is more mechanically active than chemically active in the Western deserts, the opposite in the Eastern deserts, and between the two in the Central deserts.

(3) Characteristics of sediment elemental geochemistry. The distribution of elemental geochemistry in the surface sediments of Northern Chinese deserts has obvious regional and regularity; major element SiO₂ gradually increases from west to east, while other major elements tend to decrease; trace elements Co and Cr are low in the west and high in the east, while Cu, Ga, Hf and Ni are opposite, and the remaining trace elements have no obvious trend. The degree of deficiency of each major and trace element was in the order of Eastern deserts, Central deserts and Western deserts from the highest to the lowest.

(4) Characteristics of sediment minerals. The total light mineral content in the surface sediments of the Northern Chinese deserts is low in the west and high in the east, dominated by quartz and feldspar minerals. The total heavy mineral content is high in the west and low in the east, dominated by hornblende, zoisite, garnet and iron ore minerals. The mean value of light mineral maturity is 1.76, and the mean values of heavy mineral weathering coefficient, ZTR index, ATi index and GZi index are 1.71, 5.49, 44.60 and 91.84, respectively. The mineral maturity in the Eastern deserts is higher than that in the Central and Western deserts.

(5) Characteristics of sediment organic matter and nutrients. The organic matter, total N, total P and total K content of surface sediments of Northern Chinese deserts were at low levels, with mean values of 0.32%, 0.18 g kg^-1, 0.17 g kg^-1 and 17.85 g kg^-1, respectively. Organic matter and total N showed an increasing trend from west to east, total P content showed the opposite trend, and total K content was higher in the Eastern and Western deserts and lower in the Central deserts. The spatial distribution patterns of organic matter and total N and dryness were similar, and the spatial part patterns of total P and total K were more influenced by the parent material.

(6) Spatial differences in physicochemical characteristics of surface sediments and their relationship with the modern aeolian environment. The grain size composition, particle morphology characteristics, elemental geochemical content, mineral content, organic matter and nutrient content distribution of surface sediments of Northern Chinese deserts are the result of the combined effect of climatic conditions, aeolian environment and vegetation cover. The relatively humid climate and high vegetation cover in the Eastern deserts (including Otindag, Horqin and Hulun Buir sandy lands) are important reasons for the high content of clay and silt, poor sortability, positively skewed grain size frequency distribution curves, narrow kurtosis, high frequency of chemical-genetic features on the particle surface, severe loss of unstable elements and minerals, and high organic matter and total N content. However, the strong winds in the Eastern deserts have led to an increase in coarser sand and good particle rounding. The dry climate and low vegetation cover in the Western deserts (including Gurbantunggut, Taklimakan, Kumtag, and Qaidam Basin deserts) and the Central deserts (including Badain Jaran, Tengger, Ulan Buh and Hobq deserts, and Mu US sandy land) lead to high coarse and very coarse sand, better sorting, low frequency of particle chemical genetic characteristics, element and mineral deficits are low. Due to the strong aeolian activities, the surface is severely coarsened and has a large loss of organic matter and nutrient content.

(7) Depositional environment reflected by physicochemical characteristics of sediments. The Taklimakan and Kumtag deserts’ particle surface morphology glaciation genesis occurs more frequently and suffers stronger physical weathering, indicating that the sediments have experienced cold and dry depositional environments and active wind and sand activities. The Gurbantunggut desert, Mu Us, Otindag, Horqin and Hulun Buir sandy lands have a high frequency of chemical and fluvial morphogenesis, and a high frequency of submerged polished surfaces, abrasions and indentations, which are subject to weaker physical weathering, confirming the wetter depositional environment of these deserts.