Abstract. We present the results of pollen analyses from a 1105-cm-long sediment core from Wuxu Lake in southwestern China, which depict the variations of the East Asian winter monsoon (EAWM) and the Indian summer monsoon (ISM) during the last 12.3 ka. During the period of 12.3 to 11.3 cal ka BP, the dominance of Betula forest and open alpine shrub and meadow around Wuxu Lake indicates a climate with relatively cold winters and dry summers, corresponding to the Younger Dryas event. Between 11.3 and 10.4 cal ka BP, further expansion of Betula forest and the retreat of alpine shrubs and meadows reflect a greater seasonality with cold winters and gradually increasing summer precipitation. From 10.4 to 4.9 cal ka BP, the dense forest understory, together with the gradual decrease in Betula forest and increase in Tsuga forest, suggest that the winters became warmer and summer precipitation was at a maximum, corresponding to the Holocene climatic optimum. Between 4.9 and 2.6 cal ka BP, Tsuga forest and alpine shrubs and meadows expanded significantly, reflecting relatively warm winters and decreased summer precipitation. Since 2.6 cal ka BP, reforestation around Wuxu Lake indicates a renewed strengthening of the ISM in the late Holocene; however, the vegetation in the catchment may also have been affected by grazing activity during this period. The results of our study are generally consistent with previous findings; however, the timing and duration of the Holocene climatic optimum from different records are inconsistent, reflecting real contrast in local rainfall response to the ISM. Overall, the EAWM is broadly in-phase with the ISM on the orbital timescale, and both monsoons exhibit a trend of decreasing strength from the early to late Holocene, reflecting the interplay of solar insolation receipt between the winter and summer seasons and El Niño Southern Oscillation strength in the tropical Pacific.
AbstractUnderstanding of the origin and development of bronze technology in eastern Asia remains unresolved. Here we report on the distribution of copper and associated cations in sediments from Huoshiliang in northwestern Gansu, China, strontium and lead isotope analyses of ore and slag samples, and some artifact fragments at archaeological sites at Ganggangwa and Huoshiliang in the Black River valley.We conclude that bronze production began perhaps as early as 2135 BC and that the Baishantang modern mine site at Dingxin was a possible source of copper ore. There was at least one other, but currently unidentified, source of ore. The Bronze Age people were also farmers and planted cereals such as wheat, and they may have abandoned the region when wood was exhausted and desertification took over.
Abstract. Anthropogenic activities are resulting in an increase on the use and extraction of heavy metals. Heavy metals cannot be degraded and hence accumulate in the environment having the potential to contaminate the food chain. This pollution threatens soil quality, plant survival and human health. The remediation of heavy metals deserves attention, but it is impaired by the cost of these processes. Phytoremediation and biochar are two sound environmental technologies which could be at the forefront to mitigate soil pollution. This review provides an overview of the current state of knowledge phytoremediation and biochar application to remediate heavy metal contaminated soils, discussing the advantages and disadvantages of both individual approaches. Research to date has attempted only in a limited number of occasions to combine both techniques, however we discuss the potential advantages of combining both remediation techniques and the potential mechanisms involved in the interaction between phytoremediators and biochar. We identified specific research needs to ensure a sustainable use of phytoremediation and biochar as remediation tools.
Since the mid-1980s, the conversion of land to nonagricultural use in China has been arguably the most widespread in the country’s history, and in no region has the process been more intense than in China’s coastal provinces. Among the more important factors that have contributed to the conversion of land to nonagricultural use are rural-urban migration, rapid economic growth, and increased investments in roads. A study of Landsat photographs of one south Jiangsu region reveals that because rural settlements are scattered and use a large amount of land and because urbanization and industrialization have occurred in a decentralized fashion, the shift in land use has not been restricted to a few major cities but has been widely dispersed. The article concludes by arguing that while the conversion of land to nonagricultural use in the coastal provinces is bound to continue, its pace will be slower than in the recent past.
Abstract Zircon U-Pb geochronology and heavy minerals are used in combination to provide valuable insights into the provenance of the early Eocene Jianghan Basin, central China. Five samples for zircon U-Pb dating and eighty-five samples for heavy mineral analysis were collected from drill cores or cuttings of the Xingouzui Formation. Most analyzed zircons are of magmatic origin, with oscillatory zoning. Detrital zircons from sample M96 located on eastern basin have two dominant age groups of 113–158 Ma and 400–500 Ma, and the other samples located on southern basin have three prominent age populations at 113–158 Ma, 400–500 Ma and 700–1000 Ma. Samples on different parts of the basin show distinct differences in heavy mineral compositions and they apparently divide into two groups according to the content of rutile (higher or lower than 4%). The spatial variations of zircon-tourmaline-rutile (ZTR) indices are marked by some noticeable increasing trends from basin margins to the inner part of the basin. Compared with the potential source areas, this study clarifies the multiple source characteristics of the Jianghan basin in the composite basin-mountain system. The majority of clastic material was supplied from the north source area through rift-trough sediment-transport pathways, and the eastern, southern and northwestern source areas also contributed detritus to the basin. This clastic material is broadly dispersed in the basin. The early Eocene paleogeography implies that rift architecture and rifting process had an important influence on sediment dispersal. This study shows that integrated zircon U-Pb geochronology and heavy mineral analysis is a useful and powerful method to identify sediment provenance.
Abstract Yanliaoa is a common fossil in the Middle Jurassic of western Liaoning, eastern Inner Mongolia and northern Hebei Province, China. It is an important element of the Yanliao biota. The genus was established by Pan in 1977 for fossil plants from the Middle Jurassic Haifanggou Formation in Xiasanjiaochengzi, western Liaoning Province, and in present paper, the genus Yanliaoa is studied based on new material. Pan never designated a type specimen and his fossil material cannot be located. We designate a type specimen here for Yanliaoa, so that the genus name Yanliaoa remains valid. Yanliaoa sinensis Pan emend. Tan et al., is found in the same locality and formation as the lost specimens, Y. sinensis of Pan, 1977. Yanliaoa daohugouensis n. sp., a new species with epidermal anatomy, is from the Middle Jurassic Daohugou, Inner Mongolia. A holotype is also selected from the new material for this new species. Characters of the leafy shoots and ovulate cones of Yanliaoa are emended. The epidermal anatomy of this genus is described for the first time. Compared with other extant and extinct species of Cupressaceae s. l., the current species can be distinguished from any known species both by the leafy shoot characters and its epidermal anatomy. It further indicates that Yanliaoa is an extinct and endemic conifer found in the Middle Jurassic of northeastern China.
Recent archaeological and archaeobotanical data suggest a very long tradition for the broad-spectrum subsistence economy in North China. It can be traced back at least to the Upper Paleolithic, in the last glacial maximum, and it continued into the early Neolithic period. Subsistence strategies also show great regional variation, suggesting a complex mosaic of adaptations in the transition to agriculture. The research reported here focuses on the plant-derived subsistence economy of the earliest Neolithic communities in the Daihai Lake area, Inner Mongolia, where the ecosystem was sensitive to climatic fluctuations. Neolithic groups likely migrated to the region as part of population expansion from the Central Plain. Previous scholars have suggested that this expansion was due to a search for agricultural land for millet farming. By examining residue remains and usewear patterns on sandstone grinding stone tools unearthed from the Shihushan I and Shihushan II sites, dating to the mid-5th millennium bc, we show that the earliest Neolithic settlers in Daihai appear to have enjoyed a way of life making use, and possibly management, of a wide range of plants, including various underground storage organs (tubers, roots, rhizomes, and bulbs), nuts, and wild grasses, while engaged in a limited level of millet production. This study adds to a growing literature that questions the economic significance of early cereal crops in subsistence system, suggesting that it is important to understand the role of roots and tubers in the development of early agriculture in Neolithic North China.
Using land reclamation information from gazetteers and corresponding historical records as further evidence, we extracted information about land reclamation in the early years of reclamation (at the “beginning date”) and during the climax period (the maximum extent). We analyzed land reclamation processes in the farming–grazing transitional zone in northeast China during the Qing Dynasty (1644–1911). Among thirty-seven counties for which the beginning date of land reclamation was recorded, 32 percent began reclamation early, primarily between the Shunzhi (1644–1661) and the Kangxi reigns (1662–1722), 19 percent were exploited during the Yongzheng reign (1723–1735), and 19 percent were exploited during the Guangxu reign (1875–1908). Among forty-six counties for which the maximum extent of land reclamation was recorded, the counties of Fengning, Longhua, and Longjiang were extensively exploited before 1800. From 1800 to 1860, four counties were extensively exploited, including Changtu County, Horqin Left Wi...
Alfred Russel Wallace spent eight years in South-East Asia studying the biodiversity of the region in the course of visits to Malaysia, Singapore and Indonesia. His collections, extensively and scrupulously acquired in the Malay Archipelago, include zoological specimens such as insects, birds,
Abstract West Lake's economic, social and cultural structure comprises six facets: (1) maintaining West Lake World Heritage Site as an open accessible tourist location; (2) ensuring the planning, management and tourism marketing of West Lake are culturally rather than purely economically oriented; therefore truly benefitting the preservation and conservation of West Lake; (3) selectively decreasing and mitigating the tourism pressure on West Lake, especially in those areas of high cultural, ecological and environmental vulnerability; (4) ensuring travellers adopt appropriate sustainable tourism values to enjoy a positive experience; (5) ensuring the marketing of West Lake tourism and the consequent distribution of incomes comply with legal and other appropriate standards; and (6) expanding and extending the social benefits of West Lake tourism. To aid the examination of West Lake in this paper, a comparison is made between the management policies of West Lake and Mt, Huangshan (Yellow Mountain) to illustrate a number of fundamental and organisational relationships involving tourism at heritage sites.