极地研究

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Self-organization phenomena of the nonequilibrium process in magmatism of the Fildes Peninsula, West Antarctica

Li Zhaonai, Li Hansheng, Shang Ruxiang

1996, 7 (1-English): 1-18.

摘要 ( 1078 )

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Volcanic geological,petrological and geochemical characteristics of the Tertiary volcanic rocks from the Fildes Peninsula,West Antarctica show that magma evolution was a process of dissipation of heat energy exchanged energy and mass occurring between the magma system and its surrounding environments, and with the feature of dynamic equilibrium and periodicity(stage). In the study volcanic rocks of different types commonly exhibit a multi-grade composite texture and the derivative magmas produced by differentiation of parent magymas in the magma chamber show a zonal structure in the high--level--magma chamber which represent self-organization phenomenon of the nonequilibrium process in magmatism. The self-organization phenomenon is dissipative structure formed under given conditions.

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Late Quaternary glacial-marine sedimentation in the Bransfield Strait off northeast Antarctic Peninsula

Duan Weiwu, Zhong Hexian, Li Yang

1996, 7 (1-English): 19-33.

摘要 ( 1053 )

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Systematical analyses of lithology, grain size, mineral composition, microbiological thanatocoenoses and other geological proxies from the sediments of piston core Pc10, drilled in the central part of the Bransfield Strait, have been carried out. Based on the above data,together with the shipboard investigation, the 753 cm long core sediments reveal the last 112.5 ha deposits of the study area under the glacial-marine environment. The sediments includes biogenic silica deposit, volcanic debris deposit and turbidity current deposit.Among them, the biogenic silica deposit is dominative not only in the highstand water/interglacial stage, but also in the lowstand water/glacial stage. The difference of sedimentation between the two stages was that the terrigenous debris content and the sedimentation rate were lower in the lowstand water/glacial stage.

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Paleomagnetic results of Core NP93-2 from the Prydz Bay, Eastern Antarctica

Wang Baogui, Hou Hongming, Tang Xianzan, Yuan Youren

1996, 7 (1-English): 34-40.

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Two reversal geomagnetic excursions are detected by systematically paleomagnetic measurements of the Core NP93-2 from the Prydz Bay, Eastern Antarctica.One is found in 60 to 67.5 cm from the tOP of the core, and the ¹⁴C dating age of layer 67.5 cm to 72.5 cm is 10315±800 a B.P. It is estimated that the geomagnetic excursion occurred at 9980-8880 a B.P., and perhaps was the record of the Gothenburg geomagnetic excursion (about 12000 a B.P.). The other is found in 27.5-32.5 cm,and the ¹⁴C dating age is 5390±600 a B.P., with which no generally acknowledgedgeomagnetic excursion can be compared. But a few reports of geomagnetic excursions can be used for comparing with, Zhu et al.reported a geomagnetic excursion at 4980-4770 a B.P. from peat in Beijing, Wang et al. reported a geomagnetic excursion at 5120±110 a B.P. from Core NS-89--76 in Nansha Waters and Zhou et al. reported ageomagnetic excursion at 6400-6000 a B.P. from Core QC2 in Yellow Sea. Whetherthe studied geomagnetic excursion does exist or whether those reported geomagnetic excursion are the same one is worth further study.

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The chemical compositions of Antarctic iron meteorites and their classification

Wang Daode, Chen Yongheng

1996, 7 (1-English): 41-49.

摘要 ( 1179 )

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The concentrations of 13 elements in the metal of 52 Antarctic irons have been reported and these irons have been classified based on the structures and their Ga,Ge, Ni, Ir and other trace elemental contents. The 52 iron meteorites assigned to chemical group consist of 16 of ⅠAB,12 of ⅡAB, 1 of ⅡE, 3 of ⅢAB, 1 of ⅢCD, 1 of ⅣA and 18 of ungrouped irons. The ⅠAB, ⅢCD and ⅡE iron meteorite groups areconsidered to be of nonmagmatic origin. Nonmagmatic ⅠAB, ⅢCD and ⅡE ironsformed as individual pools of a chondritic body. The other groups, ⅡAB, ⅢAB andⅣA show the evidences of having originated by fractional crystallization of a metallicmagma. The slopes on element-Ni trends in the magmatic are generally higher than inthe nonmagmatic groups. Most interestings are the high abundance Of ungrouped andⅠAB (47.2% and 27.8%,respectively) and low abundance of ⅢAB (5.8%). Antarctic irons of the group abundances can be distinguished from non-Antarctic irons, which provide the information about previously unsampled parent planets, mass, shockand collision,as well as nebula regions.

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A fossil homolodromiid crab from King George Island, Antarctica

Wang Yujing, Shi Yizhong

1996, 7 (1-English): 50-56.

摘要 ( 903 )

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Homolodromia inflata (Forster) described in this paper is found from theMiocene Cape Melville Formation of the glacio-marine sediments in King George Island, Antarctica. A comparison is made between the genera Homolodromia and Antarctidromia and a discussion is also made on the taxonomic placement of the genus Homolodromia in the Brachyura,we would like to consider that the genus Antarctidromia previously identified by Forster,may be a synonym of the genus Homolodromia.

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C₅-C₁₅ hydrocarbons in surface sediments from the Bransfield Strait, Antarctica

Tang Yunqian, Jiang Jiazhen, Lu Bing, Sui Liangren

1996, 7 (1-English): 57-69.

摘要 ( 893 )

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This paper deals with the results of comopition of C₅-C₁₅ hydrocarbons in the regions of the Bransfield Strait. The multivariate statistical analysis is made to recognize the characteristics of the sediments, resulting in that the C₅-C₁₅ hydrocarbons contain n-alkanes, iso-alkanes, cyclo-alkanes, aromatic compounds and their substituted compounds as well. The multivariate statistical analysis also shows that stations G-25 and G-27 have the extreme values of factor after rotation.

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The pedogenic groups and diagnostic characteristics in the Fildes Peninsula of King George Island, Antarctica

Zhao Ye, Li Tianjie

1996, 7 (1-English): 70-78.

摘要 ( 1269 )

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Based on the analysis of the soil-forming factors, pedogenic processes and the soil properties in the study area, this paper is to propose the soil geographico-genetic classification of maritime-climatic Sub-Antarctic regions. The soils of the Fildes Peninsula were classified into 3 soil-orders,4 suborders and 13 soil groups, and then the relationship between the soil distribution and the environment was discussed.

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Characteristics of Pc3 pulsations at Great Wall Station, Antarctica

Yang Shaofeng, Xiao Fuhui

1996, 7 (1-English): 79-85.

摘要 ( 874 )

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In this paper Pc3 pulsations at Great Wall Station of Antarctica are analyzed statistically from August 16 to November 20,1990. The occurrence frequency, frequency and polarization are studied for Pc3 pulsation events. The mechanisms of excitation and propagation of Pc3 pulsations at Great Wall Station are discussed theoretically.

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