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This article reinterprets the urban pattern of the oases of southern Tarim Basin, which flourished in the first half of the first millennium C.E. using the dispersed urban complexes framework. Disperse urban centre, also known as a low-density urban complex, is a site that had an urban function, but its morphology was much different from compact cities of, for example, China or mediaeval Europe. Low-density urban complexes, like Tikal in Mesoamerica or Angkor in South-East Asia, despite their distinct urban functions, had the cityscape consisting of intermingled monumental agriculture, water management features and agricultural field. Thus, the oasis-cities of southern Tarim Basin were different from compact urban centres of neighbouring China and western Central Asia and showed some similarities to complexes like Tikal and Angkor. This article evaluates if those sites can be associated with low-density urbanism. Three selected sites, 尼雅 [Niya], 米兰 [Miran] and 樓蘭 [Loulan], have been evaluated for the presence of characteristic associated with low-density urbanism: dispersed monumental architecture, large scale anthropogenic landscapes modifications, and pattern of alternating housing clusters and agricultural fields. This can affect our understating of both the understanding of urbanism in the region and low-density urbanism on the global scale. [ABSTRACT FROM AUTHOR]

In order to determine the source of the light hydrocarbons in the Kuqa Depression of the Tarim Basin, Northwest China, their geochemical characteristics are documented, and possible influencing factors are discussed in a broad context on the basis of geochemical analyses of natural gas samples from 19 wells in combination with previously reported natural gas components and carbon isotope values from the same depression. The biomarker analytical results show that (a) methyl cyclohexane (37.5–60.3%) of natural gas predominates the C7 light hydrocarbon series (methyl cyclohexane, heptanes, and dimethyl cyclopentane), and (b) the heptane content (25.0–54.8%) is also relatively high. The C6–7 light hydrocarbon series (aromatics, normal alkanes, and cycloalkanes) have abnormally high aromatics (benzene and toluene) content (26.2–83.8%). Heptane value (13.31–37.77%) and isoheptane value (2.10–7.64%) indicate that the Kuqa natural gases are of high maturity and typical of coal‐derived gas (gas generated by sapropelic source rock). Their light hydrocarbons, however, appear to have some characteristics of mixed‐source organic matter. Specifically, the light hydrocarbons in the Dina 2 gas field show characteristics of the coal‐derived gas; those in the Dabei gas field show some features of the oil‐associated gas (gas generated by humic source rock), whereas those in the Kela 2 and Keshen 2 gas fields and Well Yangtake‐101 display characteristics of the mixed source organic matter. The abnormally high content of the aromatics in the Kuqa Depression may have resulted mainly from their high productivity during the thermal maturity of humic type organic matters and the gases accumulation of late stage. The different relative contents of the aromatics in various oil and gas fields may have been accounted by different organic matter types, maturity, and distribution patterns of source rocks. [ABSTRACT FROM AUTHOR]

The Silk Road trade network was arguably the most important network of global exchange and interaction prior to the fifteenth century. On the question of how and when it developed, scholars have focused mainly on the role of either the empires dominating the two ends of the trade network or the nomadic empires on the Eurasian steppe. The sedentary people of Central Asia have, however, mostly been neglected. This article traces the development of the city-states of the Tarim Basin in eastern Central Asia, from c. 2000 bce to 400 bce. It argues that the development of the city-states of the Tarim Basin is closely linked to the rise of the ancient Silk Road and that the interaction between the Tarim polities, the nomads of the Eurasian steppe and the Han Empire was the central dynamic in the creation of the ancient Silk Road network in eastern Central Asia. [ABSTRACT FROM PUBLISHER]

The Holocene hydrological history of Lop Nur in northwestern China's Tarim Basin and its response to climate conditions are inferred from a relatively well-dated multi-proxy record including grain-size, pollen and spores, and soluble salt data. A dated pit section (YKD0301) with a depth of 570 cm in the center of the dry Lop Nur Basin was investigated. The sediments contain a total of twenty fining-upward cycles as a result of strong discharge from the catchment to the lake during relatively wet conditions. The fluvial sediments were probably widely dispersed by wind-driven waves and currents in the large and shallow basin of Lop Nur. Higher runoff and dilution of lake waters are also indicated by lower contents of soluble salt in the sediments and recorded ostracod shells of brackish and oligohaline to freshwater species. In contrast, sediment sections with smaller mean grain size and fewer flood layers are dominated by aeolian sediments which were accumulated during drier periods. Ostracod shells are mostly lacking from these sections, suggesting a higher salinity in the lake. Lop Nur experienced six stages during the last 9 ka. Relatively wet conditions existed between 9.0–8.9, 8.7–5.1 and 2.4–1.8 ka, with periods of increased aridity in between and after 1.8 ka. The lowest salinity was recorded between 8.7 and 5.1 ka which represents the wettest phase during the last 9 ka and probably the regional Holocene Optimum. Relatively wet climate conditions between 2.4 and 1.8 ka and dry conditions afterwards possibly first fostered and later on caused the devastation of the ancient Loulan Kingdom in the region. The uppermost sediments of the section represent a massive salt crust formed during the final desiccation of the lake in the last century. The effective moisture change pattern of the Lop Nur region is roughly consistent with synthesized Holocene moisture records for western China dominated by the westerlies. [ABSTRACT FROM AUTHOR]

Summary Mulched drip irrigation for cotton field is an effective measure for the utilization of saline water, and the regulation of soil water and salt. However, the reasonable methods for quantifying actual evapotranspiration (ET) and deep percolation of recharge to groundwater are still not very well understood, which restricts the accurate regulation of soil water and salt for cotton growth in oasis. In this paper, a set of experiments of mulched drip irrigation with brackish water were conducted in a typical arid region of Tarim basin in southern Xinjiang, China. The irrigation events were recorded, and ET and fluctuations of groundwater table were carefully measured for two consecutive irrigation periods of flowering and bolling stages. A group of upscaling conversion methods were used to quantify the ET, in which canopy structure was considered to estimate the transpiration from leaf scale to a unit of field scale. The groundwater table had a significant response to the irrigation events, thus the deep percolation was estimated using water-table fluctuation method (WTF). Results showed that during the two irrigation events of flowering and bolling stages, the total ET was 31.1 mm with the soil surface evaporation of only 0.4 mm. The total percolation of recharge to groundwater was 48.2 mm which contributed to the groundwater run-off of 22.1 mm. Transpiration of 30.7 mm accounted for 98.6% of the total ET of 31.1 mm and 34.3% of the irrigation water of 90.6 mm. Compared with transpiration, the deep percolation accounted for 53.2% of irrigation water, indicating a serious excessive irrigation that recharged to groundwater. Soil salt budget showed that the salt leached into groundwater was 1.56 times of the input from brackish irrigation water and fertilization during the two irrigation periods. Even for the irrigation practice with brackish water, the accumulated salt of soil profile could also be leached out under large amount of irrigation water (e.g. 90.6 mm for the two irrigation periods, 10 days). However, the waste of enormous water which for instance occupied 53.2% of the irrigation water in this study was not conducive to the sustainable utilization of water resources in the arid oasis. Furthermore, the methods introduced in this paper for ET and deep percolation calculation of cotton filed could be used to quantify the oasis hydrologic cycle of micro-irrigation, to gain a better understanding of the ecological process. [ABSTRACT FROM AUTHOR]

Biomarkers are stable compounds of carbon- carbon skeleton in the sedimentary rocks or oil, and are usually used in oil correlation and palaeosedimentary environment restoration. An attempt to use biomarkers to divide and correlate strata is made in the paper. The studies show that the regular sterane distribution Of the Cambrian-Low Ordovician in the Tarim Basin was quite different from that of the Middle-Upper Ordovician. The former shows a C28 sterane content higher than the latter, and the regular sterane has an inverted "L" pattern distribution of C29>C28>C27. The latter has a C27 sterane content higher than the former and the sterane has a "V" pattern distribution of C29>C27>C28. The sterane distribution of Cambrian- Lower Ordovician and the Middle-Upper Ordovician changed from the inverted "L" into a "V" pattern, showing that during the evolutionary process of organisms, the organic origin & chemical structure components obviously changed. This may be used in the Lower Paleozoic stratigraphic division and correlation in the Tarim Basin. [ABSTRACT FROM AUTHOR]

Sedimentary provenance studies based on detrital zircon ages have proved to be a powerful tool for elucidating detailed patterns of erosion and sediment dispersal on and adjacent to the continents. This approach is commonly used to examine processes that occur over discrete intervals of geologic time, but it can also be used to address fundamental questions concerning the longer-term evolution of the continental crust. Central Asia, for example, consists of a Palaeozoic accretionary collage that contrasts with the cratonal cores of continents such as North America, which were fully consolidated during the Proterozoic. Detrital zircon provenance may thus provide important insights on the comparative evolution of these distinctly different styles of continental growth. The Tarim sedimentary basin is interpreted to be underlain by a micro-continental block that accreted to central Asia during the late Palaeozoic. Detrital zircon in pre-Permian strata of the northern Tarim basin includes Precambrian grains derived from Tarim basement, and Palaeozoic grains related to active tectonism along its margins. During this phase of tectonic amalgamation, overall sediment maturity increased up-section, consistent with similar observations from other cratons. However, in Tarim these trends reverse dramatically in Mesozoic and Cenozoic strata deposited after amalgamation of Tarim with central Asia. Palaeozoic zircon grains derived from the Tian Shan become dominant, Precambrian grains drop to trace abundances, and sandstone composition shift abruptly to immature litharenite. Moreover, a progressively increasing temporal gap occurs between zircon age and depositional age, reflecting the near absence of post-amalgamation magmatic or high-grade metamorphic rocks within the Tian Shan. Collectively, these observations support a model of Tarim and other central Asian basins as islands of long-lived tectonic stability, within an orogenic collage that has remained mobile for >250 million years. [ABSTRACT FROM AUTHOR]

The Loplyks form a small ethnic group previously settled at the Lop Lake (Lop Nor) in the Tarim Basin. With an economy based on fishing, this semi-nomadic Turkic group adapted to the arid conditions and scarce biological resources at the fringe of the Takiamakan desert. In the late nineteenth century, foreign travellers observed that they could fulfil most of their material needs through the use of available plants, animals, and fish species. Anthropogenic pressure and climate change have dried Lop Nor and forced the Loplyks to turn into farmers. This article discusses their adaptation strategies from an ethnobiological viewpoint. [ABSTRACT FROM AUTHOR]