极地研究

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Study on the relationship between the diameter of the compound eye and the growth of the Antarctic krill

Sun Song, Wang Rong

1996, 7 (2-English): 87-93.

摘要 ( 1258 )

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Correlation between the body length and the diameter of the compound eyeof the Antarctic krill Euphausis sulfa was examined. From the samples collected inthe late summer, it shows that there is an apparent exponential relationship betweeneye diameter and the body length. From the laboratory population, it seems that whenthe krill shrink, the diameter of the compound eye does not decrease. It is more reliableto use the eye diameter as krill growth index than they length. The ratio of the theylength to the diameter of the compound eye offers another method for detecting the effect of shrinking in natural populations of krill.

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A Sm-Nd mineral isochron of mafic granulite from the Sφstrene Island, East Antarctica

Ren Liudong, Liu Xiaohan

1996, 7 (2-English): 94-98.

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Redetedrination of the metamorphic age of the gsrnet-bearing mafic wholeulite from the Sstrene Island, Esat Antarctica has been made and an isochron of wholerock-garnet-pyroxene-plagioclase is obtained, giving an age of [604±28(2σ)] Ma. It is pointed out that this age represents the time of peak granulite facies metamorphism ofthe area. As to the geological relation of the Sstrene Island with the Bolingen Islandsand the Larsemann Hills to the east, it is deduced from the rock assemblages, metamorphic superposition, spatial changes and metamorphic ages between the above regions that the degree of the superposition of the later low pressure metamorphism is becoming stronger from west to east. While the evolution of the earlier medium pressure to later low pressure implies probably the substages of the same metamorphic cycle.

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Petrological characteristics of the sedimentary volcaniclastic rocks of the Fossil Hill Formation (eocene) in King George Island, West Antarctica

Xue Yaosong, Shen Yanbin, Zhuo Erjun

1996, 7 (2-English): 99-117.

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The Fossil Hill Formation of the type section composed chiefly of the sedimentary-volcaniclastic breccia and tuffites can be divided into two cycles of sedimentation. The thermal fluid was active in the coarse volcaniclastic deposits of the lower cy-cle, it led to the formation of laumontite, analcite, albite and regularly hybrid mineral of interlayered chlorite and montmorillonite, which are absent from the upper cycle, and to the transportation and concentration of some of trace elements between the coarser tuffites and the overlying fine tuffite bed at the upper part of this cycle. So-called "rainprint" and "mud crack" actually are non-sedimentary originally, they were formed respectively by sheddillg of the small zeolitized concretions on the bedding plane and tectonic pressed stress. The evidences indicate that the Fossil Hill Formation of the Fossil Hill section was deposited in an intermontane lake affected by both volcanic action andseasonal flail under the condition of worm and moist climate.

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Preliminary study on late Quaternary foraminiferal assemblagein the Bransfield Strait, West Antarctica and its significance ofenvironment

Chen Chaoyun

1996, 7 (2-English): 118-125.

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21 species foraminifera, including in 14 genera were encountered from 39samples of core PC10, which were drilled in the Bransfield Strait of Antarctic Peninsula. They are divided into 3 assemblages as follow: 1. Siliceous shell assemblage; 2. Calcareous shell assemblage; 3. Mixed shell assemblage. The Siliceous shell assemblageoccurred in normal deep-sea, with weaker water dynamic condition. The Calcareousshell assemblage was formed by turbidity now, while the Mixed shell assemblage represented intense to weaker water dynamic condition. It changed from warm to cold towarm during the late Quaternary.

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A Study of Foraminifera in the core NP93-2 from the prydz Bay, Antarctica

Tu Xia, Zheng Fan

1996, 7 (2-English): 126-140.

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Analyses of foraminiferal fauna in the core np93-2 of the prydz bay,Antarctica shows that the sediments are rich in foraminifera in which planktonic Foraminifera make up 26.3% of the total number of foraminifera and the arenaceous Agglutinated benthic foraminiferal assemblages are prevailing with 57.9% of total Number of benthic foraminifera. The typical benthic foraminiferal assemblage of Iammina arenacea represents an assemblage of deep-water arenaceous agglutinated.Variations of content of warm and cold species of planktonic foraminifera reflect the Paleoclirnatic changes and also reveal the paleo-environmental changes in this region andIts relationship with the global changes. Other paleoceanographic and Paleoclimatological questions, such as water depth, carbonate dissolution are also discussed.

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Holocene ostracoda and sedimentary environment implication in The core NG93-1 from the Great Wall Bay, Antarctica

Cai Huimei

1996, 7 (2-English): 141-149.

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The Holocene ostracode are analyzed from the core sample NG93-1 collectedIn the Great Wall Bay, Antarctica during 1992～1993. Totally 11 genera 21 species have been identified in the sediments, of which the most abundant is Loxoreticulatum fallax, the second abundant are Xestoleberis keguelenensis, Xestoleberis spp., Semicytherura spp., Australicythere polylyca, etc. Most species of ostracodes are those known in Antarctic area. Base on the study of ostracodes from the core NG93-1, their sedimentary environment may be of shore-shallow sea.

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Vertical distribution and seasonal variation in ice algae biomass in coastal sea ice off Zhongshan Station, East Antarctica

He Jianfeng, Chen Bo

1996, 7 (2-English): 150-163.

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The biomass of ice algal communities in coastal sea ice off Zhongshan Station, Antarctica were monitored from April to December 1992. The maximum thickness of ice cover was 1.74 m in November/December and covered-snow was less than 35 cm in depth throughout the study period. Brown layers occurred in 2～5 cm of the ice bottom in late April and November, with chlorophyll a peak values of 360.7 and 2810 mg/m³ respectively. The integrated chlorophyll a values ranged from 1.17 to 59.7 mg/m² with the peak occurring in November when ice algae bloomed, and the values never exceeded 6 mg/m² before mid October except at one site, the highest value occurred in April and then decreased nuctuatedly throughout the year. The biomass was concentrated mainly in the bottom of the ice, and might be also partly concentrated in the interior sections where autumn bloom had occurred. The dominant diatoms were Composed of Nitzschia lecointei, N. Barkleyi, N. Cylindrus in austral autumn and Amphiphiprora kjellmanii, Berkeleya rutilans, Nitzschia lecointei in austral spring, and showed some difference at sites owing to the environmental conditions.

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Holocene glacial-marine sedimentation in the Prydz Bay, Antarctica

Wu Shigui, Luo Youlang, Wang Youqiang, Lu Jun, Zheng Fan, Sun Shaoxian

1996, 7 (2-English): 164-172.

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The typical glacial-marine sedimentation has been recorded from core NP93-2 in the Prydz Bay, Antarctica. The sedimentation processes, sedimentary environment and paleoclimate variations since 12937 a B. P. have been discussed, based on grain size, mineral composition and micropaleontological data, etc.. The climate variation occurred at 10 ha, which expressed that there were increased inputs of terrigenous clastics. The climate change once again but temporarily took place at late Holocene.

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