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1.
There are 37 lakes in the Qaidam Basin: 1 freshwater lake, 6 brackish-water lakes, 2 saline-water lakes and 28 salt lakes. The pH value of salt lake brines is 7.014 on the average, and the average total mineralization is 340.75 g/1. Their water bodies belong mainly to the five-component equilibrium system,: Na, K, Mg//SO4, Cl-H2O, which can be further grouped into sodium-magnesium sulfate subtype, magnesium sulfate subtype, chloride transition subtype and chloride type water by their hydrochemical property. The salt lake brines of the first salt forming epoch (N2−Q3) were of the sulfate type. In the second salt forming epoch (Q3−Q4), some of them were of the chloride type. The pH value of brines decreases with the increase of total mineralization. The pH value is lower when the total mineralization is from 50–310 g/l and higher when the total mineralization is from 310–355 g/l, however, when the total mineralization is higher than 355 g/l, the pH value decreases slowly again. The total mineralization of the chloride type and the chloride transition subtype brine is higher than the sulfate type, being 310–530 g/l, 310–470 g/l, and less than 355 g/l in that order. Of the 40 chemical compositions in the saline lake brines in Qaidam Basin, potassium is mainly concentrated in the chloride type and chloride transition subtype brine, boron and lithium mainly in the sulfate type. Evaporation experiments show that boron and lithium are accumulated in concentrated brine until crystallization of bischofite takes place. Potassium is also accumulated in concentrated brine during the salt forming stage, but its concentration decreases with the increase of total mineralization during the potassium forming stage. This paper was published in Chinese inOcean. et Limn. Sinica;15 (4):341–359, 1984.  相似文献   

2.
It is well known that there are two patterns of potash deposition in lacustrine facies: “tear drop pattern” (the Dabsan saline lake is a typical example) and “bull's eye pattern”. Potash-forming in tear drop pattern is still continuing. The 2,678 m A. S. L. lake in the middle of the Qarhan playa in the Qaidam Basin covers an area of 210 km2, and has an average depth of 0.39 m. Its MgCl2 type surface brine is 280–340 g/l in salinity and mainly consists of Na, K, Mg and Cl. As a rule, the potash deposits occur as evaporite distributed in tear drop pattern at the northern and northeastern lakeshore zones. They mostly consist of carnallite and halite, occasionally sylvite. The deposition is very unstable and controlled principally by the varying supply of deposit materials from the Golmud River in the south. The potash deposits were formed when concentration of the surface brine reached a certain degree in the main evaporating season. Their forming process followed some crystalization paths in the phase diagram for the Na, K, Mg/Cl H2O equilibrium system. Such a sedimentary model of potash deposits in the lacustrine facies is relatively common in nature. Under the extremely arid climate, differential concentration of the nonhomogeneous potassium-rich surface brine produced the potash deposits. Qarhan Salt Lake also had the same pattern of potash depositions and so, in a sense, the Dabsan saline lake is the continuation of the Qarhan salt lake in terms of potash formation. Schmalz (1970) put forward two distributive patterns for evaporite: “tear drop pattern” and “bull's eye pattern”. These patterns exist in both marine and continental salt-bearing basins (including recent salt lakes), and are controlled by the conditions of physical geography, hydrogeology, sedimentology and climatology of each basin. In his works (Sun, 1981; 1984; 1986; 1988) on the origins of potash deposits, the author always referred to them as two models of potash formation. The “tear drop pattern” is one of the salt-forming models and also an important potash-forming model. This paper deals with the formative mechanism of the tear drop pattern potash deposition by presenting the Dabsan saline lake as an example and elucidates on the distributive characteristics and formative processes of potash deposits in the lake.  相似文献   

3.
The author made an approximate dating of the highest shorelines of the three larger interior lakes and proved that during late Q3 or early Q4, there existed a higher lake level in the plateau, reflecting that the climate then was much more moist than it is today. It could be presumed from a study of these two ages that such higher lake levels correspond with both the last glacial epoch (i. e., the latter half) and the lowest sea level of the East China Sea then. Moreover, interpretations of aerial photos and an on-the-spot survey revealed that since then these lakes had 8–10 rhythms of retreat, indicating that the climate in central Asia and the plateau at that time had 8–10 comparatively arid periods. As the plateau is still in the faster process of upheaval, it is expected that on a longterm basis, the climate in this region will tend to be continuously dry. However, should there be a neo-glacial epoch in the world, and if the higher lake level really corresponds to the glacial epoch, then in the not distant future, the lake level will possibly rise again to some extent. Thanks are due to the No. 2 Institute of Oceanography of SOA for its analyses of C14 dating specimens. This paper was published in Chinese inOceanologia et Limnologia Sinica 17(3): 207–216, 1986.  相似文献   

4.
Features of Sand-dust Deposits in Harbin City, China   总被引：1，自引：0，他引：1  
1 Introduction The sand-dust storm weather, induced by special at- mospheric circulation in specifically geologic and geo- graphic environment, is disastrous one with little prob- ability and excessive harm. In China, the sand-dust storm frequency of every 10 years had increased from 4 times in the 1950s to 23 times in the 1990s (Zhuang et al., 2001). The sand-dust weather occurring in a large area of the northern China in the spring of 2002 had attracted much attention. People are gradually…  相似文献   

5.
Progress of limnology in China   总被引：1，自引：0，他引：1  
The following six aspects in the utilization of lake resources and progress of limnological research in China are described: 1. Expeditions for comprehensive investigation of lakes; 2. Physical limnology; 3. lacustrine sedimentology and paleolimnology; 4. Hydrobiology and ecology; 5. Hydrochemistry and environmental protection; 6. Development and utilization of lake resources. This paper was published in Chinese inScientia Limnologica Sinica 1 (1): 1–11, 1989.  相似文献   

6.
This paper, based on field data and experimental results, gives an analysis and summary of the types and salt-forming characteristics of salt lakes in Xinjiang, and the distribution and chemical compositions of their brines and groups of salt minerals. The evolution and substance origins of the salt lakes and their salt-forming regularities as seen from analyses of their paleogeographic environment and geological tectonics are also reported. This paper will serve as a reference for further investigation of the Xinjiang salt lakes, and as a guide for fuller utilization of their resources. This paper was published in Chinese inOcean. Limn. Sinica 15(2):168–178, 1984.  相似文献   

7.
ＲＥＬＡＴＩＯＮＳＨＩＰＢＥＴＷＥＥＮＱＩＮＧＨＡＩＬＡＫＥＬＥＶＥＬＤＥＳＣＥＮＤＩＮＧＡＮＤＡＲＴＩＦＩＣＩＡＬＷＡＴＥＲ－ＣＯＮＳＵＭＰＴＩＯＮ￥ＰｅｎｇＭｉｎ（彭敏）ＣｈｅｎＧｕｉｃｈｅｎ（陈桂琛）ＺｈｏｕＬｉｈｕａ（周立华）（Ｎｏｒｔｈｗｅ...  相似文献   

8.
ＩＮＴＲＯＤＵＣＴＩＯＮＣｈｌｏｒｉｎｅｈａｓｔｗｏｎａｔｕｒａｌｌｙｏｃｃｕｒｉｎｇｓｔａｂｌｅｉｓｏｔｏｐｅｓ,　35Ｃｌａｎｄ　37Ｃｌ.Ｓｅｖｅｒａｌｓｔｕｄｉｅｓｒｅｐｏｒｔｅｄｔｈｅｖａｒｉａｔｉｏｎｓｉｎｔｈｅｉｓｏｔｏｐｉｃｃｏｍｐｏｓｉｔｉｏｎｏｆｃｈｌｏｒｉｎｅｉｎｎａｔｕｒｅ.Ｈｏｗｅｖｅｒ,ｉｎｔｈｅｅａｒｌｙｙｅａｒｓＯｗｅｎａｎｄＳｃｈａｅｆｆｅｒ(1955)ｒｅｐｏｒｔｅｄｎｏｏｂｓｅｒｖａｂｌｅｄｉｆｆｅｒｅｎｃｅｉｎｔｈｅ　37Ｃｌ35Ｃｌｒａｔｉｏｓｉｎｔｅｎｓａｍｐｌｅｓｅｘ…  相似文献   

9.
Component data of the saline lakes in Xizang were obtained from field observations in recent years (1976, 1978). Laboratory studies show that there are nearly 37 chemical components in 63 lakes brine and 27 evaporative minerals in nearly 40 saline lakes that reach their depositional stage. Their formative conditions, distributive properties, assemblage properties of some salt minerals, and mechanisms affecting the components of the saline lakes are discussed. A sedimentary model of the early Holocene epoch saline lake is suggested. This work is an aid not only to the understanding of the formation of the saline lakes in the said area, but also to the use of their mineral resources. This paper was published in Chinese inOcean. Limn. Sinica, 1983,14 (4): 342–352.  相似文献   

10.
ＤｕｒｉｎｇｔｈｅｔｈｒｅｅＭｔ．ＱｏｍｏｌａｎｇｍａＥｘｐｅｄｉｔｉｏｎｓｏｆ１９５９－１９６０，１９６６－１９６８ａｎｄ１９７５，ＣｈｉｎｅｓｅｓｃｉｅｎｔｉｓｔｓｈａｄｏｂｔａｉｎｅｄｍａｎｙｄａｔａｏｆｇｌａｃｉｅｒｓｉｎｔｈｅｄｉｓｔｒｉｃｔｏｆＭｔ．Ｑｏｍｏｌａｎｇｍａ（Ｗａｎｇｅｔａｌ．，１９８０；Ｘｉｅｅｔａｌ．，１９７５；Ｚｈａｎｇｅｔａｌ．，１９７５）．ＩｎＭａｙ１９９７，Ｐｒｏｆ．ＱｉｎＤａｈｅａｎｄＰｒｏｆ．ＰａｕｌＡ．Ｍａｙｅｗｓｋｉｏｒｇａｎｉｚｅｄａｎｏｔｈｅ…  相似文献   

11.
1INTRODUCTIONTheWestLake ( 30°1 5′N ,1 2 0°1 6′E)isasmallshallowlakeinthewesternpartofHangzhouCityinthesoutheasterncoastalareaofChina.Thelakeissur roundedonthreesidesbyhills ;andisfamousforitspicturesquesceneryandinterfusionofhillsandwaterbodies.Thesurfaceareaisabout 5 .66km2 andmeandepthis 1 .8m .Beforethe 1 95 0s ,thelakewaterwascleanandmacrophytesgrewveryluxuriantlyinthelit toralareasofthelake .In 1 95 2 ,WestLakewasdredgedand 70 0× 1 0 4m3 mudwasremovedfromthebottomofthelake …  相似文献   

12.
Duetoregionalhydrogeologicandclimaticconditions,inthewesternSongnenPlain,themostdistinctcharacteristicofwaterenvironmentinlimnicwetlandsisthatmanywaterbodieshavehighsaltcontentsandpHvalues,andsomelimnicwetlandsbelongtosaltmarshes.Thelimnicwetlandsofthisregionarespecialnaturecomplex.Itisimportantfortheutilizationofwetlandresourcesandtheintegrateddevelopmentofsaline-alkalinesoiltostudychemicalcharacteristicsofwaterenvironmentinthisregion.1NATURALENVIRONMENTCHARACTERISTICSOFTHEWE…  相似文献   

13.
ＩＮＴＲＯＤＵＣＴＩＯＮＪｏｈａｎｎｅｓ (1 965)ｆｉｒｓｔｓｈｏｗｅｄｔｈｅｉｍｐｏｒｔａｎｃｅｏｆｐｒｏｔｏｚｏａａｓｒｅｍｉｎｅｒａｌｉｚｅｒｓｉｎｍａｒｉｎｅｅｎｖｉｒｏｎｍｅｎｔｓ.Ｔｈｅｓｉｇｎｉｆｉｃａｎｃｅｏｆｐｒｏｔｏｚｏａｉｎｔｈｅｆｒｅｓｈｗａｔｅｒｆｏｏｄｗｅｂｈａｓｂｅｅｎｋｎｏｗｎｆｏｒｔｈｅｐａｓｔ2 0ｙｅａｒｓ.Ｐｒｏｔｏｚｏａｉｓａｍａｉｎｐｒｅｄａｔｏｒｏｆｐｌａｎｋｔｏｎｉｃｂａｃｔｅｒｉａａｎｄｐｈｙｔｏｐｌａｎｋｔｏｎ ,ａｎｄａｌｓｏａｆｏｏｄｓｏｕｒｃｅｏ…  相似文献   

14.
1　ＩＮＴＲＯＤＵＣＴＩＯＮＩｔｉｓｖｅｒｙｉｍｐｏｒｔａｎｔｔｏｒｅａｌｉｚｅｔｈｅｄｉｓｔｒｉｂｕｔｉｏｎｓｏｆｐｏｌｌｕｔａｎｔｓｂｅｆｏｒｅｔｈｅｐｏｌｌｕｔｉｏｎｃａｎｂｅｃｏｎｔｒｏｌｌｅｄｓｕｃ ｃｅｓｓｆｕｌｌｙ .Ｏｗｉｎｇｔｏｔｈｅｌａｃｋｏｆｓｙｓｔｅｍａｔｉｃａｌｏｂｓｅｒｖａ ｔｉｏｎｓｉｎａｂｒｏａｄａｒｅａ ,ｎｕｍｅｒｉｃａｌｓｉｍｕｌａｔｉｏｎｈａｓｂｅ ｃｏｍｅａｐｏｗｅｒｆｕｌｔｏｏｌｔｏｕｎｄｅｒｓｔａｎｄｔｈｅｄｉｓｔｒｉｂｕｔｉｏｎｓｏｆｐｏｌｌｕｔａｎｔｓａ…  相似文献   

15.
Two hundred and thirty-five samples collected from Weinan loess section (L2 – S0) have been analyzed by TOC (total organic carbon) and pyrolysis hydrocarbons. The curve of TOC with depth has been set up and compared well with other climatic markers. The main periods of TOC variation of the last 0.14 Ma are 67.08 ka and 18.29 ka, which is near with the periods of the variation of sunshine, showing that the TOC variation may be controlled by the variation of 65°N sun-shine. The distribution of pyrolysis hydrocarbon and its parameters shows that there are two kinds of hydrocarbon associated with climatic change. One is called hydrocarbon pyrolysted directly from organism (pHC2–1) which is in the range of T max350°C – 500°C, and associated with atmospheric water. The other is called carbonate inclusion hydrocarbon (pHC2–2) which is in the range of T max 500°C – 600°C and formed by evaporation and associated with dry climate. The formula calculating humidity has been deduced Og=pHC2–1/(pHC2–1 + pHC2–2). The range of humidity of the section is 47% – 77% and the reducing order is S1–3, S1–2, S0, S1–1, S1–4, S1–1, L1–1, L1–3, and L1–5. And the trend of the humidity is still increasing today.  相似文献   

16.
The abyssal circulation in the Philippine Sea(PS)is investigated,with outputs from the Simple Ocean Data Assimilation version 2.2.4(SODA224).The deep-water currents in SODA224 are carefully evaluated,with sparse in situ observations in the North Pacific Ocean.In the upper deep layer(20003000 m)of the PS,a strong westward current,which originates from the Northeast Pacific Basin and enters the PS through the Yap-Mariana Junction,exists along 1114 N.This strong westward current bifurcates into two western boundary currents off the Philippines.The northward-flowing current flows out of the PS around 2021 N,whereas the southward-flowing current transports deep water from the northern hemisphere to the southern hemisphere.In the lower deep layer(30004500 m),the inflow water first flows northward to the east of the Western Mariana Basin and then turns westward at approximately 18 N.The inflow water mainly enters the Philippine Basin(PB),with a small part turning southward to constitute a weak cyclonic circulation.The water entering the PB mainly merges into a strong southward western boundary current in the south-ern PB.In the bottom layer(below 4500 m),both the northeast and northwest PB show single cyclonic gyres,whereas the south PB shows a single anticyclonic gyre.Moreover,comparisons with the observations indicate the possible existence of a cyclonic sense of circulation over the Philippine Trench.The current study provides the implications for future observations,which are needed to fur-ther investigate the temporospatial variations of the abyssal circulation in the PS on multiple scales.  相似文献   

17.
The total organic carbon (TOC) content series from the lake sediment of Minqin Basin (100°57′–104°57′E, 37°48′–39°17′N) in northwestern China, which has a 10 000-year-long paleo-climatic proxy record, was used to analyze the Holocene climate changes in the local region. The proxy record was established in the Sanjiaocheng (SJC), Triangle Town in Chinese, Section (103°20′25″E, 39°00′38″N), which is located at the northwestern boundary of the present Asian summer monsoon in China, and is sensitive to global environmental and climate changes. Applying singular spectrum analysis (SSA) to the TOC series, principal climatic oscillations and periodical changes were studied. The results reveal 3 major patterns of climate change regulated by reconstructed components (RCs). The first pattern is natural long-term trend of climatic change in the local area (Minqin Basin), indicating a relatively wetter stage in early Holocene (starting at 9.5 kaBP), and a relatively dryer stage with a strong lake desiccation and a declined vegetation cover in mid-Holocene (during 7–6 kaBP). From 4.0 kaBP to the present, there has been a gradually decreasing trend in the third reconstructed component (RC3) showing that the local climate changed again into a dryer stage. The second pattern shows millennial-centennial scale oscillations containing cycles of 1 600 and 800 years that have been present throughout almost the entire Holocene period of the last 10 000 years. The third pattern is a millennial-centennial scale variation with a relatively smaller amplitude and unclear cycles showing a nonlinear interaction within the earth’s climate systems.  相似文献   

18.
1 INTRODUCTION Carbon dioxide (CO2) is principal greenhouse gas. Its air-water exchange is important in terrestrial ecosystems for climate change (Frankignoulle et al., 1998; Schimel et al., 2001). The direction of CO2 gas movement depends on the CO2 concentration gradient between air and surface water. The amount of CO2 exchange is related to the gas exchange coefficient, k. All lakes, with their small area but large atmospheric CO2 flux are important to under-stand the CO2 fluxes …  相似文献   

19.
The 4.45 m-thick pure ice lens have been discovered firstly at depth from 19.81 -24.26 m in the bore No.6, which locates in north bank of the Ngoring Lake. In source region of the Huanghe (Yellow) River, 14C dating, X -ray diffraction, pollen analysis, micropalaeontology, chemical components, environmental isotope 2H, 3H, 18O and freezing point of the ice and water samples from the bore have been tested and microorganism in the ice have been also appraised with microscope. Combined with the research on geomorphy and Quaternary around the lake, the ice lens are determined as a kind of deep-buried lake ice, formed in 35,030-45,209 yr.B.P., and annual mean air temperature was about -10℃ during that time.  相似文献   

20.
Salt lakes,the main source of trona resources in China, are widely distributed on the Inner Mongolian Plateau. Their characteristics are large in number, various in type, and short in salt-forming stage, especially their considerable number is well-known at home and abroad. The paper discusses the physical constituents, hydrochemical features, classification, formation, evolution, and salt-forming regularities of salt lakes through analyzing their distribution, lacustrine deposits and salt-forming conditions.  相似文献   

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