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    30 September 1998, Volume 10 Issue 3 Previous Issue    Next Issue

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    THE 40 Ar 39 Ar AGES OF HORNBLENDES IN GRT PL BEARING AMPHIBOLITE FROM THE LARSEMANN HILLS, EAST ANTARCTICA AND THEIR GEOLOGICAL IMPLICATIONS
    1998, 10 (3):  4-14. 
    Abstract ( 1211 )   PDF (537KB) ( 1426 )  

    In this paper we reported the 40 Ar 39 Ar dating results of hornblendes in Grt Pl bearing Amphibolite from the Larsemann Hills, East Antarctica. Their apparent ages respectively are 1586Ma, 1011-1080Ma, 761Ma, 529-582Ma. Their plateau ages of 1036Ma and 554Ma as well as an Ar Ar isochron age of 1010Ma have also been obtained respectively. These isotopic dating results for the first time by the Ar Ar method for hornblendes completely record almost all the structural metamorphic thermal events that this region experienced, and provide an answer to the controversial question on the structural metamorphic thermal events of this region in recent several years, namely, the late Proterozoic 1000Ma event (Grenvillian) and the early Palaeozoic 500Ma event (Pan African) which one is more important than another, as well as whether the former exists or not. The 40 Ar 39 Ar dating results of hornblendes show that the Larsemann Hills experienced a complicated poly metamorphic evolutionary history, and their protoliths probably formed in early to mid Proterozoic. The late Proterozoic 1000Ma event (Grenvillian) has been confirmed to be a predominant tectonothermal event whilst the early Palaeozoic 500Ma event (Pan African) has been confirmed just to be the last strong tectonothermal event in this region.

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    CHARACTERISTICS OF MAJOR ION CONCENTRATIONS IN SNOWPITS IN LONGYEARBYEN, SVALBARD, ARCTIC
    1998, 10 (3):  15-23. 
    Abstract ( 1315 )   PDF (500KB) ( 1194 )  

    Snowpits samples were collected from three glaciers in the Longyearbyen region, Svalbard. By the analysis of samples, it is showed that Cl - and Na + which mainly from sea salt are dominated among soluble impurities in snowpits, and their concentrations are far higher than others. Ca 2+ which mainly comes from continent has highest concentrations in dirty layer of snowpits which were formed in autumn. Then snowpits have been dated by high values of Ca 2+ concentrations and δ 18 O, which represent autumn and summer layer, respectively. Seasonal variations in concentrations of sea salt ions, SO 2- 4and NO - 3 have been identified. Results indicate that concentrations of sea salt ions and SO 2- 4and NO - 3 show high value in spring, resulting from long range transport of marine aerosol from north Atlantic storms and mid latitude anthropogenic pollution, respectively. Also concentrations of sea salt ions and SO 2- 4 , NO - 3 show high value in summer. High concentrations of sea salt ions in summer are contributed by local marine aerosol, SO 2- 4 reflect local marine aerosol, high scavenging ratios and oxidation of marine biogenic emissions, NO - 3 may reflect lighting in atmosphere and high scavenging ratios. By comparing ions concentrations between in Longyearbyen and other remote regions, such as Greenland, Antarctic and Qinghai Tibetan Plateau, it is showed that ion concentration in snowpits is higher in Longyearbyen than other regions, especially for concentrations of sea salt ions.

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    THE SEDIMENTARY PROCESS ANALYSIS OF AB 67 DRILLING CORE IN BARROW,ALASKA
    1998, 10 (3):  24-33. 
    Abstract ( 1334 )   PDF (305KB) ( 1125 )  

    The systematic multi variable analysis of sedimentary environment on the grain size data and geochemical data of AB 67 drilling core in Barrow is given in this paper. Results show that 32-60 cm section of the core is continental deposits, and this sedimentary environment and process are stable and steady;20-32cm section is a transition period from continental deposits to marine sediments, and magnetic mineral with Cr decrease sharply,the oxides of Si and Ca reduce, one of Ti and Fe increase, organic matter raise;10-20 cm is marine sediments, coase grain is a little, oxide, silt, organic matter and adsorbed composition fluctuate greatly, leached remain composition speed to increase in surface layer, the source of matter is stable, but dynamic environment change greatly.

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    DISTRIBUTION OF SNOW ALGAE AT KING GEORGE ISLAND, ANTARCTICA WITH REFERENCE TO PHYSICAL AND CHEMICAL CHARACTERS OF SNOW
    1998, 10 (3):  34-46. 
    Abstract ( 1358 )   PDF (1228KB) ( 1253 )  

    Species composition and distribution of snow algae were studied at King George Island,Antarctica with reference to physical and chemical characters of colored snow such as snow condition,pH,conductivity and nutrient concentration of meltwater to assess the environmental factors influencing the distribution of snow algae. Most snow algae were members of Chlorophyta. Cyanophyceae and Bacillariophyceae were poorly represented compared with other freshwater habitats. Ecological studies were carried out on coastal communities of Fildes Peninsula and Ardley Island using three types of snow:red snow dominated by red resting cells of green alga,green snow dominated by a filamentous green alga, Klebsormidium sp. and brown snow dominated by a coccoid chrysophycean alga. Red and brown snow tended to occur on coarsely granulated,while,green snow tended to occur on waterlogged snow. Although pH was the same in all colored snow ( 5-6) , both conductivity and NH 4 N concentration in meltwater of green snow were higher than those of red and brown snow. Chlorophyll a contents of green snow were much higher than those of red snow. Relationship between Chlorophyll a content and nutrient concentrations of NH 4 N,PO 4 P were not clear in both red and green snow. Among studied environmental factors,snow condition,and both conductivity and NH 4J N in snow meltwater were considered to influence the distribution of snow algae.

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    THE DEPLETION OF NUTRIENTS AND THE ESTIMATE OF THE NEW PRODUCTION IN THE ICE EDGE IN PRYDZ BAY,ANTARCTICA
    1998, 10 (3):  47-54. 
    Abstract ( 1651 )   PDF (242KB) ( 3032 )  

    The distributions and changes of nutrients in Prydz Bay were investigated during CHINARE 6 and CHINARE 9, and the new productions were estimated by using mass balance method. The results showed that in CHINARE 6, the consumptions of NO 3 N、PO 4 P、SiO 3 Si were 1064.8、69.2、2196.9mmol/m 2,the uptake ratio of N and Si to P were 15 3, 31.7,respectively, and new production was 992.4 mgC/(m 2·d) ; and that in CHINARE 9, the depletions of NO 3 N、PO 4 P was 551.9、41.2mmol/m 2,respectively,the uptake ratio of N to P was 13.4,and the new production was 390.1 mgC/(m 2·d),indicating significant annual and /or seasonal variation. New productions were both greater than the primary production determined by 14 C trace method,demonstrating there existed rather higher new production in Prydz Bay in austral summer. The uptake ratio of nutrients in Prydz Bay, however, is different from the previous values obtained from the open sea,showing the regional difference of uptake and regeneration of nutrients in Southern Ocean. Finally the annual change of new production and the characteristics of phytoplankton production were discussed.

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    THE CONTENT OF COD Mn OF THE GREAT WALL BAY AND ADJACENT SEA AREAS,ANTARCTICA
    1998, 10 (3):  55-59. 
    Abstract ( 1363 )   PDF (294KB) ( 1228 )  

    During 1993.12 ̄1994.2, the COD Mn of the Great Wall Bay, Antarctica and its adjacent sea areas was investigated. The COD Mn of 39 stations was from 0.3342 mg/L to 1.9590mg/L; the high value was at the research stations, and the value of the inner Great Wall Bay was higher than that of the outside. The reason of the change of the COD Mn was studied; the main resource of the COD Mn was analysed.Some of the pollution comes from the research stations,but most of it may come from the living beings. The wind and wave is one of the most important factors affect the values of COD Mn . Suggestions were given to protect the environment of Antarctica.

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    SEM STUDIES ON THE PLANT MORPHOLOGY OF SCHISTIDIUM BRID. FROM FILDES PENINSULA, ANTARCTICA
    1998, 10 (3):  60-64. 
    Abstract ( 1410 )   PDF (802KB) ( 1196 )  

    Three species from Fildes Peninsula,Antarctica belonging to the genera Schistidium Brid. were observed under SEM.They are S. hyalino cuspidatum;S. rivulare;S urnulaceum . The leaf surfaces,the leaf cells and the morphological characteristic of the sporophyte were reported in detail. A key for the genus, and short historical notes on the taxonomy of all species,have been provided.Habitat and distribution data for each species together with full lists of all specimens examined are also given. The length of the seta varies from 0 2mm to 0.5mm, perichaetial leaves in Schistidium are mostly similar to the vegetative leaves in shape, but often longer, wider and have longer hair points. Symmetric, obovate to oblong ovate capsules are common in three species of Schistidium. The character of operculum falling with the columella in Schistidium is the most significant features in separating the genus from all species of Grimmia that have opercula falling detached from the columella.

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    A 342 DAY CONTINUOUS OBSERVATION OF THE BLOOD PRESSURE,HEART RATE AND BODY TEMPERATURE OF A MEMBER AT ZHONGSHAN STATION, ANTARCTICA
    1998, 10 (3):  65-71. 
    Abstract ( 1208 )   PDF (399KB) ( 1010 )  

    This paper reported a 342 day continuous observation of the blood pressure,heart rate and body temperature of a member during his long term stay at Zhongshan Station, Antarctica. The result showed that there was no obvious change in the subject diastolic blood pressure,but his night systolic blood pressure,heart rate and the average of his body temperature all increased obviously, unrelated to the changes in air temperature, atmospheric pressure and relative humidity. There was no clear change in his systolic blood pressure and body temperature during polar night. During the night, his diastolic blood pressure increased, though not to a significantly different level, his diastolic blood pressure dropped obviously, and his heart rate also clearly increased. During polar day, his blood pressure,heart rate and temperature were higher in the morning than in the evening, though both remained in the normal range. Also during polar day, his morning systolic blood pressure and the atmosphere pressure, his night systolic blood pressure and the relative humidity, as well as his night body temperature and the relative humidity were all obviously positively correlated. Comparing polar night and day, there was no obvious difference in his morning systolic blood pressure and his body temperature, while there was obvious difference in his heart rate. His diastolic blood pressure during polar night and body temperature were both lower than the measures during polar day. This study can possibly provide some valuable information for the study of Circulative Physiology and Applied Physiology in the special environments.

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    CHANGES IN CARDIAC FUNCTION OF ANTARCTIC RESEARCH EXPEDITION MEMBERS IN THE GREAT WALL STATION DURING SUMMER
    1998, 10 (3):  72-77. 
    Abstract ( 1241 )   PDF (324KB) ( 1225 )  

    male members of Chinese 6th Antarctic Research Expedition were divided into two age-groups: gp.1, n=17, 30.8±1.1 yrs.; gp.2, n=11,48.0±1.7 yrs.. The dynamic changes in their cardiac function were determined with NCCOM 3 noninvasive cardiovascular monitor ( American Bomed Medical Mfg. Ltd.). The results indicated that short staying and working at the Great Wall Station during summer has no marked effect on heart function, but the people of elder age is behind the young in heart ability for adaptation to Antarctica.

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    SOLID ELECTRICAL CONDUCTIVITY MEASUREMENT OF POLAR ICE CORES AND ITS ENVIRONMENTAL SIGNIFICANCE
    1998, 10 (3):  78-83. 
    Abstract ( 1224 )   PDF (248KB) ( 1409 )  

    Current emphasis upon the high resolution profiles established from ice cores has drawn attention to electrical conductivity measurement(ECM) in ice core studies.In this paper,we describle the technological methods of ECM system and analyse the advantages of ECM on rapid measurement,high spatial resolution and little wreckage.And the applications and progresses of ECM data in ice cores are classified.In addition,particular effort has been made in clarification of the environmental record significance of ECM data to improve a better undersanding of ECM data in ice core studies.

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