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30 March 2003, Volume 15 Issue 1 Previous Issue    Next Issue
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CHARACTERISTICS OF QUARTZ GRAIN SURFACE TEXTURES IN THE ANTARCTIC ICE-FREE AREA 2003, 15 (1):  1-11.  Abstract ( 1314 )   PDF (399KB) ( 1637 )   Relative frequency distributions of the various surface textures recorded on quartz grains can indicate the depositional environment. Surface textural analysis of quartz grains under some representative sedimentary environments on the Fildes Peninsula were performed by Scanning Electron Microcopy (SEM). The results suggest that glacial transportation had occurred on the most of quartz grains from various depositional environments in ice free area of King George Island and this correspond well to extensive glacial debris. Furthermore, there are some differently characteristic textures present on quartz grain from various depositional environments in studying area. For example, V shaped pits show high enough frequencies on modern beach sands, suggesting high energy subaqueous transport, and the striations were produced largely on the tills. Based on the data for surface texture occurring frequency, we classify samples into different groups in order to identify their depositional environment. The results show that ancient beach sands were preserved in the second, the third, the fifth marine terraces, and F 1 sample is predominantly composed of tills. These judgments are supported by filed survey. Therefore, surface textural analysis of quartz grains can be used as effectively auxiliary criterion for identification of depositional environment in Antarctic ice free area. Related Articles | Metrics

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WATER PROPERTIES OF THE SEAS SURVEYED BY CHINESE FIRST ARCTIC RESEARCH EXPEDITION IN SUMMER,1999 2003, 15 (1):  11-20.  Abstract ( 1723 )   PDF (158KB) ( 1921 )   Based on the conductivity temperature depth (CTD) data obtained within the Bering Sea, Chukchi Sea and south Canada Basin by Chinese First Arctic Research Expedition from July to September 1999, the assemblies of water mass in the three area are analyzed: (1) The water mass in the Bering Sea consists of the Upper Water changed with season, the Intermediate Water and the Deep Water (2) The Chukchi Sea water is influenced by input water of outer sea and variation of sea ice. The hydrographic features are different in July from in August evidently. Water mass assemblies in the Chukchi Sea are defined as distorted water for shallow sea and include the Chukchi summer water and the input water source from the north Pacific Ocean and Arctic Ocean. (3)In the south Canada Basin, the main components of water mass are the Arctic Surface Water effected by variation of sea ice, the Arctic Subsurface Water of Pacific origin, the Arctic Intermediate Water of Atlantic origin and the Arctic Deep Water. Related Articles | Metrics

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The REEs GEOCHEMISTRY OF CHUKCHI SEA SEDIMENT CORE 2003, 15 (1):  21-27.  Abstract ( 1741 )   PDF (267KB) ( 1589 )   Sediment core samples were collected from the continental shelf of the Chukchi Sea in July 1999 and rare earth elements (REEs) were measured by instrumental neurton activation analysis (INAA). The abundance of the REEs is very similar to values for fine grained continental shelf sediment. The downward profiles of the REEs show a slightly increasing trend with depth and the variation of the REEs is relatively smooth. The shale normalized REEs distribution pattern is rather flat with Ce negative anomaly, suggesting there exists biological source to the REEs in the sediment. The REEs is positively correlated with Al and enrichment factos calculated with respect to the crustal abundance is close to 1, which indicates the REEs in Chukchi Sea sediment are predominantly of continental origin. Related Articles | Metrics

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THE BIOGEOCHEMISTRY OF CARBON CYCLE IN SUMMER OF THE PRYDZ BAY, ANTARCTIC Ⅰ: CHARACTERISTICS OF DOC DISTRIBUTION 2003, 15 (1):  28-34.  Abstract ( 1601 )   PDF (267KB) ( 1700 )   The distributions and changes of dissolved organic carbon in the Prydz Bay and outer open sea were investigated during CHINARE 15 (the 15th Chinese National Antarctic Research Expendition). The results showed that the content of DOC was higher in the Prydz Bay and outer open sea compared to those typical surface oceanic levels (70—80μM), average content of DOC in the surface water was 102.32μM, the range was 68.23—125.92μM. The vertical distribution of DOC in the water column was similar to many ocean sites, that is to say, the content of upper water is higher than deep water, a subsurface maximum persisted between 25—50m. The DOC pool in the Prydz Bay consisted of labile, semi labile and refractory pools, in which refractory pools was main part. The concentration of refractory DOC was 92.34 and 76.89μM in Prydz Bay and outer open sea, and accounted 77% and 825 for total DOC, respectively. Related Articles | Metrics

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DETERMINATION OF ICE THICKNESS, SUBICE TOPOGRAPHY AND ICE VOLUME AT GLACIER NO.1 IN THE TIEN SHAN, CHINA, BY GROUND PENETRATING RADAR 2003, 15 (1):  35-44.  Abstract ( 1480 )   PDF (210KB) ( 1672 )   We describe a radio echo sounding (RES) survey for the determination of ice thickness, subglacial topography and ice volume of Glacier No.1, in Tien Shan, China, using ground penetrating radar (GPR). Radar data were collected with 100 MHz antenna that were spaced at 4 m with a step size of 8 m. As our study shows, the GPR radar survey method works well on alpine glaciers in low latitude, high altitude China. Very clear bedrock echoes were observed in radar images. The images produced from GPR clearly show the continuity of bedrock echoes. The undulation of the bedrock surface, indicates that GPR radar survey provides for fundamental data on glacier thickness, subice topography and ice volumes, which can contribute new knowledge and better understanding of glacier dynamics, glacier fluctuation and climate change, glacial erosion processes as well as providing estimates of glacier water reserves. Radar results show that the maximum ice thickness of Glacier No.1 is 133m, the average thickness of east branch is 58.77m and that of west branch is 44.84m. And ice thickness along east branch main ice flow line of Glacier No.1 averages at 85.3m and ice thickness along west branch main ice flow line of Glacier No.1 averages at 66.5m. Based on the map of ice thickness, we know the thickest part of the glacier lies near the main flow line in the central area of the glacier. Ice volume calculations based on radar data provide support to the studies of glacier fluctuations and estimation of the glacial water reserves. For Glacier No.1, in Tien Shan, the ice volume of east branch is 51.87×10 6m 3, which of west branch 20.21×10 6m 3. Subglacial topography features revealed by glacier radar images show that bedrock is more undulating than the glacier surface topography, indicating that the amplitude of the bedrock undulation decreases with increasing distance above the bedrock. The surface relief does not vary with the of the bedrock on Glacier No.1. The morphologies of glacier valley cross sections differ greatly in different parts of the glacier, which helps us to understand the impacts of glacier valley cross sections on glacier motion. Related Articles | Metrics

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STUDY ON POLLEN MORPHOLOGY OF TUNDRA PLANS FROM BARROW, ARCTIC 2003, 15 (1):  45-52.  Abstract ( 1603 )   PDF (355KB) ( 2020 )   Barrow is located in the northeast of Alaskan coastal plain (71°21' N, 156°40' W),which is encircled by the Chukchi Sea in the west and the Beaufort Sea in the north. Thus, it is considered to be a key region for studying the land ocean interaction related to climatic and environmental changes. Climatically, Barrow is a quite cold area with the mean annual temperature of -12.4°C and the mean winter and summer temperatures ranges between -29°C and 2°C. Mean annual precipitation is less than 250mm/a.Under cooperative arrangement between Chinese Academy of Science and the North Slope Borough, Alaska, Zhang Qingsong and Tang Lingyu, two of the authors of this paper made a four week field investigation at Barrow from May to June, 1998. During the expedition, 31 plants,26 pollen surface samples were collected in the tundra and drilled in Elson Lagoon and small lakes. The persent article deals with pollen morphology of tundra plants from Barrow area . Investigation on pollen grains from 12 species belonging to 12 genera and 11 families shows that 6 types of aperture are found and may be summarized as follows: 3 colpate; 3 colporate; 3 colpoidorate; 6 colporate; Pantoporate and Teraheroporate. Related Articles | Metrics

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PROGRESS IN PHYSICAL OCEANOGRAPHIC STUDIES OF PRYDZ BAY AND ITS ADJACENT OCEANIC AREA 2003, 15 (1):  53-64.  Abstract ( 1861 )   PDF (414KB) ( 2240 )   Based on the literature mainly published in the recent 30 years, this paper summarizes the progress in physical oceanographic studies of Prydz Bay and its adjacent Oceanic area. The main contents of the paper are: 1. scientific significances for studying the physical oceanography of Prydz Bay and its adjacent ocean; 2. summary of the field expeditions related to the studied region; 3. water mass distribution and the physical characteristics; 4. measurements and analyses of oceanic currents in the region. At the same time, the scientific achievements and the recent progress made in all the aspects mentioned above are delineated. Finally insufficiencies in the observations and studies in the past years are discussed and some proposals for the futrue improvement are suggested in the paper. Related Articles | Metrics

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ROCK-WEATHERING BY LICHENS IN ANTARCTIC: PATTERNS AND MECHANISMS 2003, 15 (1):  65-72.  Abstract ( 1751 )   PDF (433KB) ( 1956 )   Saxicolous species of lichens are able to induce and accelerate weathering of their rock substrates, and effects of lichens on substrates can be attributed to both physical and chemical causes. This paper is focused on biotic weathering actions of epilithic and endolithic species on the different rock types (sandstones and volcanogenic rocks) in Antarctica. The patterns, mechanisms, processes and neoformations of rock weathering attribute to lichen colonization are expounded in detail. Furthermore, it is pointed out that, for a better undrstanding of the impacts of lichens on environments the studies on the rate of biotic weathering and the comprehensive involvement of the lichen effects on weathering of natural rocks remain to be carried out in Antarctica. Related Articles | Metrics

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MOLECULAR MECHANISM OF COLD-ADAPTATION OF POLAR MICROORGANISMS 2003, 15 (1):  75-82.  Abstract ( 1896 )   PDF (429KB) ( 3253 )   Polar microorganisms possess specially genetic, physiological and biochemical properties for the uniquely geographic and climatic features in Antarctic and Arctic. The cold temperature of polar environment has a wide ranging influence on all of the microbial ecosystems of this region. Adaptation mechanisms of polar microorganisms for this environmental factor are studied in detail in recent years. This paper briefly describes the advances in molecular mechanism of cold adaptation of polar microorganism in aspects including low temparature enzymes, cell membrane, cytoplast and so on. Related Articles | Metrics