Ma Haizhou

Timing and style of Late Quaternary glaciation in northeastern Tibet

Glacial successions in the Anyemaqen and Nianbaoyeze Mountains of northeastern Tibet are reassessed and new glacial chronologies are presented for these regions. Cosmogenic radionuclide and optically stimulated luminescence dating indicates that two glacial advances occurred in marine isotope stage (MIS)-3 and MIS-2. In the Anyemaqen Mountains, a third advance occurred in the Early Holocene. We suggest that glaciation was synchronous in the Anyemaqen and Nianbaoyeze Mountains, as well as in other glaciated areas of Tibet and the Himalaya that are influenced by the Asian monsoon. The maximum extent of glaciation occurred early in the last glacial cycle (MIS-3) during a time of increased insolation when the monsoon intensified and supplied abundant precipitation, as snow at high altitude, to feed high-altitude glaciers. This suggests that precipitation, as snow, is fundamental in controlling glaciation in these regions. However, the occurrence of glacial advances during the insolation minimum of MIS-2 suggests that, despite reduced precipitation at this time, the annual temperatures were cold enough to maintain positive glacier mass balances. The numerically defined chronologies for the Anyemaqen and Nianbaoyeze Mountains presented here provide a framework for comparing glacial advances in other parts of high Asia.

Characteristics of chlorine isotope distribution and analysis on sylvinite deposit formation based on ancient salt rock in the western Tarim Basin

During formation of the Tarim Basin, there repetitively happened seawater invasion for it was ever connected with wide Paleo-mediterranean Sea. At the same time, for the application of tectonic and paleoenvironmental condition, the basin deposits many sequences of thick strata of evaporites, especially in its two largest subbasins of Kuqa in the north and Shaqa in the southwest. Therefore, the western Tarim Basin has been considered to be a favorable location to prospect ancient sylvinite deposit. But it is unfortunate that the Br×103/Cl ratio, as a common geochemical index to uncover clues of sylvinite deposit, is almost invalid to indicate the stage of ancient brine condensation for very low content of bromine in salt rock samples (less than 10−6 commonly) in the western Tarim Basin evaporites. Fortunately, we noticed recently that the values of chlorine isotope (δ 37Cl value) for salt rock samples follow some clear laws from place to place, which in the Shaqa subbasin, all δ 37Cl values of salt rock samples behaved negatively and on the contrary, they all surprisingly showed positive values in the Kuqa subbasin. Based on conclusions of previous research and referring to the ratios of Br×103/Cl for salt rock or brine samples, we proved that the chlorine isotope (δ 37Cl) could be used as an effective index to find ancient sylvinite deposit in those evaporites rock basin with low content of Br element background, such as the Tarim Basin. Thus according to the new index of chlorine isotope, we conclude that the concentration of ancient brines formed ancient salt rocks is much more concentrated in the Shaqa subbasin than that in the Kuqa subbasin. Particularly, the δ 37Cl value of salt rock in Kashi depression of the western Shaqa subbasin is greatly negative (<-1.00‰), which may predicate that the ancient brine has been concentrated to the terminal stage of salt deposit or even the later stage of sylvinite deposit. Then it is possible to find sylvinite-bearing deposits around the western region (periphery of Kashi depression) of the Shaqa subbasin if we carry out more careful exploration in later works.

Content Variations of Rubidium and Bromide in Sylvite Derived from Carnallite by Leaching of Magnesium Chloride

The relationship between sylvinite and carnallite is important in the potash mine body contained carnallite,especially sylvinite overlies carnallite,the reverse of a normal depositional sequence.Trace elements are more

The effectiveness of small-to-medium river basin organizations in China: a case study of the Erhai Lake Basin Management Commission

Drawing on empirical evidence from a case study conducted in the upper Mekong catchment, this article assesses the performance of the Erhai Lake Basin Management Commission, an organization mandated to control pollution and integrate the diverse interests of those individuals and communities living and working near Erhai Lake. Clear local rules, strong enforcement, practical protocols, clear responsibilities and extensive mobilization have been crucial to the success of this small river basin organization. However, the insufficient involvement of numerous important stakeholders in decision-making processes has decreased the commission’s capacity to address water issues.

Stable Isotope and Element Geochemistry of Saline Springs in Evaporite-bearing Mengla Basin,South Yunnan,China

1 Introduction Mengla Basin is a sub-basin in southern evaporitebearing Lanping-Simao Basin.There are many salt springs in the basin.In 2012,11 spring samples were collected for analyses of chemistry and boron,hydrogen and oxygen

Geochemistry of Brines from Salt Ore Deposits in Western Tarim Basin

In the geological evolution of the Tarim Basin, many transgressions and relictions happened. So there have been plentiful sources of salt. Moreover, because of uttermost drought, a lot of salt has been deposited. It is possible to find potash salt in this area. In our fieldwork, we have found salt and brine in western Tarim Basin. Based on a geological survey and the characteristics of sedimentary facies and paleogeography, this paper deals with the geochemical parameters and discusses the possibility of formation of potash salt in terms of the chemical analyses of samples collected from western Tarim Basin. Results of brine analysis lead to some conclusions: most of these salt brines have eluviated from very thick halite beds, mainly chloride-type salt and this kind of halite does not reach the stage of potash deposition in all aspects; WK-SL (Wukeshalu) occupies a noticeable place, and we should attach importance to this district because there have been some indicators of the occurrence of potash deposits as viewed from the contents of Br and K. Finally, low Br contents are recognized in the Tarim Basin as a result of salt aggradation, and this point of view has been proved by the results of this experiment and the data available. It cannot depend upon the index of Br to judge the evolution stage of halite. We must look for other facies of potash except marine facies.