Late Palaeogene palynoflora from Point Hennequin of the Admiralty Bay , King George Island, Antarctica with reference to its stratigraphical significance

１ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅＫｉｎｇＧｅｏｒｇｅＩｓｌａｎｄ,ｌｏｃａｔｅｄａｔ６１°５０′６２°１５′Ｓａｎｄ５７°３０′５９°００′Ｅ,ｉｓｔｈｅｌａｒｇｅｓｔｏｎｅａｍｏｎｇｔｈｅＳｏｕｔｈＳｈｅｔｌａｎｄＩｓｌａｎｄｓ．Ｉｔｃｏｎｓｉｓｔ...     

Postglacial marine environmental changes in Maxwell Bay, King George Island, West Antarctica

Sediment textural properties and total organic carbon (TOC) contents of three sediment cores from Maxwell Bay, King George Island, West Antarctica, record changes in Holocene glaciomarine sedimentary environments. The lower sedimentary unit is mostly composed of TOC-poor diamictons, indicating advanced coastal glacier margins and rapid iceberg discharge in proximal glaciomarine settings with limited productivity and meltwater supply. Fine-grained, TOC-rich sediments in the upper lithologic unit suggest more open water and warm conditions, leading to enhanced biological productivity due to increased nutrient-rich meltwater supply into the bay. The relationship between TOC and total sulfur (TS) indicates that the additional sulfur within the sediment has not originated from in situ pyrite formation under the reducing condition, but rather may be attributed to the detrital supply of sand-sized pyrite from the hydrothermal-origin, quartz-pyrite rocks widely distributed in King George Island. The evolution of bottom-water hydrography after deglaciation was recorded in the benthic foraminiferal stable-isotopic composition, corroborated by the TOC and lithologic changes. The ع⁸O values indicate that bottom-water in Maxwell Bay was probably mixed gradually with intruding ¹⁸O-rich seawater from Bransfield Strait. In addition, the ع³C values reflect a spatial variability in the carbon isotope distribution in Maxwell Bay, depending on marine productivity as well as terrestrial carbon fluxes by meltwater discharge. The distinct lithologic transition, dated to approximately 8000 yr BP (uncorrected) and characterized by textural and geochemical contrasts, highlights the postglacial environmental change by a major coastal glacier retreat in Maxwell Bay.     

东南极普里兹湾NP93－2柱样古地磁结果

对东南极普里兹湾海区ＮＰ９３－２柱样的古地磁研究，结果指示出两个地磁场反极性漂移，其中之一位于６０－６７．５ｃｍ，而６７．５－７２．５ｃｍ处经１４Ｃ测年为１０３１５±８００ａＢ．Ｐ．，推算该反极性漂移的年龄为９９８０－８８８０ａＢ．Ｐ．，可能是哥德堡反极性漂移（Ｇｏｔｈｅｎｂｕｒｇ，１２０００ａＢ．Ｐ．前后）在该沉积物中的记录；另一反极性漂移位于２７．５－３２．５ｃｍ处，经１４Ｃ测年为５３９０±６００ａＢ．Ｐ．。国际上所见报导的资料中尚无相应年龄的反极性事件可以与之对比。只有国内一些地区发现的反向极性漂移记录与之接近，但这些反极性漂移是否为同一事件的反映，或该反极性漂移本身是否真实存在，目前还难于论定，有待今后进一步工作加以证实     

Temperature distribution of Collins Ice Cap,King George Island,Antarctica

ＴｅｍｐｅｒａｔｕｒｅｄｉｓｔｒｉｂｕｔｉｏｎｏｆＣｏｌｌｉｎｓＩｃｅＣａｐ，ＫｉｎｇＧｅｏｒｇｅＩｓｌａｎｄ，ＡｎｔａｒｃｔｉｃａＨａｎＪｉａｎｋａｎｇ（韩建康）ａｎｄＪｉｎＨｕｉｊｉｕｎ（金会军）（ＬａｎｚｈｏｕＩｎｓｔｉｔｕｔｅｏｆＧｌａｃｉｏ...     

Development of Antarctic herb tundra vegetation near Arctowski station,King George Island

We studied the development of the Antarctic herb tundra vegetation formation in relation to the history of deglaciation across a range of habitats near H. Arctowski Research Station (King George Island, South Shetland Islands). Across the three identified environmental zones (coastal, intermediate, periglacial), we quantified the total vegetation cover, cover of the two indigenous flowering plants and bryophytes, age structure and reproductive features of the two flowering plants, and species diversity of mosses and liverworts. Analysis of these data supported the recognition of the three environmental zones; however, there were few indications of systematic differences in biological features of the two higher plants across the three zones, generally supporting the view that these, and the grass Deschampsia antarctica in particular, are effective primary colonists of recently deglaciated ground in this region.     

Collins Glacier Retreat Process and Regional Climatic Variations,King George Island,Antarctica

This paper investigates the recent climatic variability and changes in snow line and ice front position in Collins Glacier, King George Island, South Shetland Islands, Antarctic Peninsula. This region has recorded one of the largest temperature increases in the past fifty years and has been demonstrated to be highly sensitive to climate changes. To monitor recent changes (1983–2006), we determined the fluctuations of the terminus and snow line of the glacier via remote sensing data and field observation in the summer of 2013. We conclude that the Collins Glacier has responded slowly to regional climate changes (decades or even centuries), as glacial responses to climatic events do not depend solely on one environmental variable. The glacier presented more retreat and elevation of the snow line in the north sector. The retreat data are correlated with the mean monthly temperature and annual number of days of melting‐degree variations.     

Geochronologic evidence for Early Cretaceous volcanic activity on Barton Peninsula, King George Island, Antarctica

Ages of six volcanic and plutonic rocks on Barton Peninsula, King George Island, were determined using ⁴⁰Ar/³⁹Ar and K-Ar isotopic systems. The ⁴⁰Ar/³⁹Ar and K-Ar ages of basaltic andesite and diorite range from 48 My to 74 My and systematically decrease toward the upper stratigraphic section. Two specimens of basaltic andesite which occur in the lowermost sequence of the peninsula, however, apparently define two distinct plateau ages of 52-53 My and 119-120 My. The latter is interpreted to represent the primary cooling age of basaltic andesite, whereas the former is interpreted as the thermally-reset age caused by the intrusion of Tertiary granitic pluton. The isochron ages calculated from the isotope correlation diagram corroborate our interpretation based on the apparent plateau ages. It is therefore likely that volcanism was active during the Early Cretaceous on Barton Peninsula. When the K-Ar ages of previous studies are taken into account with our result, the ages of basaltic andesite in the northern part of the Barton Peninsula are significantly older than those in the southern part. Across the north-west-south-east trending Barton fault bounding the two parts, there are significant differences in geochronologic and geologic aspects.     

Holocene paleoclimate changes determined using diatom assemblages from Lake Long,King George Island,Antarctica

Formation of Lake Long, King George Island, Antarctica started about 4,000 years B.P., after which the diatom community changed in response to environmental shifts driven by climatic oscillations (warm/wet and cool/dry). Successive sequences of diatoms in a 7.5-m drill core were divided into 11 assemblage zones by cluster analysis. The most obvious change was an alternation of major dominants, Achnanthes minutissima, Fragilaria alpestris and Fragilaria pinnata v. antarctica according to the climatic oscillations in the late Holocene. Variations in diatom assemblages clearly reflect two warm periods, a single cool period, and three transition periods. The recent warm period (zones 2 and 1) has persisted for approximately 450 years, perhaps sufficiently long to suggest the imminent onset of a new transition period. A recent high TOC (total organic carbon) value in the core reflects a warm period in Antarctica during the late Holocene.     

Determination of element composition of three lichens and their distribution in King George Island, Antarctica

Cross-section slices of Usnea antarctica Du Rietz, Usnea aurantiaco-atra (Jacq.) Bory. and Cladonia sp. at upper, middle and basal positions were prepared, respectively. The element composition and relative content were determined by SEM and EDS at the surface, intermediate and inner layers in each slice, respectively. The result indicated that the composition of element is mostly same in these lichens. The relative content of Al, Si, K and Ca elements is high,and P is close at each position. The result is of benefit to study the structure and physiological characteristics of lichens, and to analyze geological environment in Antarctica.     

Holocene environmental change according to lake core in Fildes Peninsula of King George Island,Antarctica

Lake core sampled from Xihu in Fildes Peninsula of King Gorge Island, Antarctica could reveal the environmental change of the district. The lake core( GA7) , 9.28 meters long , was sectioned at an interval of 2 cm. Through measuring the organic carbon, magnetic susceptibility, granularity and organic carbon isotope of GA7, by use of 14C age it was estimated that there were four periods of high temperature in Fildes Peninsula; 4800-4400 aB. P. , 3600-3350 aB. P. ,2100 - 1800 aB. P. and 900 aB. P. - present. Meanwhile, results showed that there was a strikingly positive correlation between the content of organic carbon and that of organic carbon isotope (δC01213 ) which could be the substitute indicators of environmental temperature.     

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

（赵烨）（李天杰）ＴｈｅｐｅｄｏｇｅｎｉｃｇｒｏｕｐｓａｎｄｄｉａｇｎｏｓｔｉｃｃｈａｒａｃｔｅｒｉｓｔｉｃｓｉｎｔｈｅＦｉｌｄｅｓＰｅｎｉｎｓｕｌａｏｆＫｉｎｇＧｅｏｒｇｅＩｓｌａｎｄ，Ａｎｔａｒｃｔｉｃａ￥ＺｈａｏＹｅａｎｄＬｉＴｉａｎｊｉｅ（Ｉ...     

A preliminary study on oxygen isotope of ice cores of Collins Ice Cap,King George Island,Antarctica

ＡｐｒｅｌｉｍｉｎａｒｙｓｔｕｄｙｏｎｏｘｙｇｅｎｉｓｏｔｏｐｅｏｆｉｃｅｃｏｒｅｓｏｆＣｏｌｉｎｓＩｃｅＣａｐ，ＫｉｎｇＧｅｏｒｇｅＩｓｌａｎｄ，ＡｎｔａｒｃｔｉｃａＹａｎＭｉｎｇ（闫明）ＰｏｌａｒＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｏｆＣｈｉｎａ...     

Soils of Fildes Peninsula, King George Island, the maritime Antarctic: Part~-> Formation processes and pedogenetic particu-larities

Based on the data obtained from tens of the investigated soil profiles scattered over the Fildes Peninsula, King George Island, the maritime Antarctic, the soil forming processes were discussed. It was concluded that on the weathering crusts resulted from various physical courses, the strong freeze thaw action within regolith, significant organic matter accumulation, evident leaching and illuviation, as well as initial argillification dominated the formation and development of the soils on the Fildes Peninsula. Furthermore, this study indicated that the juvenility of genesis, poor profile expression, variation in column thickness, etc. characterized the pedogenetic features of the soils of the Fildes Peninsula.     

Composition of plagioclases in volcanic rocks of King George Island, Antarctica with reference to the petrogenetic significance

Plagioclases occur mainly as phenocrysts in volcanic rocks of King George Island, South Shetland Islands, West Antarctica. In basaltic andesites and andesites of Keller Peninsula and Ullman Spur (Admiralty Bay), they are high structure state labradorite andesines; and in high Al basalts and basaltic andesites of Barton and Weaver peninsulas (Maxwell Bay), they are high structure state bytownite anorthites.∑[WT9.BZ]REE, La/Yb ratios and δEu values of plagioclases from Admiralty Bay are higher than those from Maxwell Bay. All plagioclases have rather identical chondrite normalized transitional element distribution patterns, probably reflecting that crystal structure rather than composition of plagioclase controls their diversity. Compositions of plagioclases depend chiefly on those of their host rocks, compositional differences of plagioclases reveal that basaltic magmas in the Admiralty Bay area are more evolved than in the Maxwell Bay area.     

Climate， mass balance and glacial changes on small dome of Collins Ice Cap， King George Island， Antarctica

Ｃｌｉｍａｔｅ，ｍａｓｓｂａｌａｎｃｅａｎｄｇｌａｃｉａｌｃｈａｎｇｅｓｏｎｓｍａｌｌｄｏｍｅｏｆＣｏｌｌｉｎｓＩｃｅＣａｐ，ＫｉｎｇＧｅｏｒｇｅＩｓｌａｎｄ，ＡｎｔａｒｃｔｉｃａＷｅｎＪｉａｈｏｎｇ（温家洪）ａｎｄＫａｎｇＪｉａｎｃｈｅｎｇ（康建成...     

Ecological differences of south polar skua populations from Fildes Peninsula of King George Island and eastern Larsemann Hills, Antarctica

A study has been done on the comparison of nesting and feeding behavior, population variances as well as breeding success between two populations of south polar skua (Catharacta maccormicki) from near Great Wall station on Fildes Peninsula and near Zhongshan station in Eastern Larsemann Hills, Antarctica. There are evident differences in their population ecology. The foraging habit is much related to regional ecosystem and food resources near their territorial area. Dependence on human food waste influences skua's diet,which considerably affects their behavior even population variation in both areas. The skuas in Zhongshan Station,could shorten and/or regulate the timing for their egg laying and hatching, and take precedence of one chick brooding, for keeping their breeding success, and subsequent species continuation.     

Holocene diatom flora and stratigraphy from sediment cores of two Antarctic lakes (King George Island)

The diatom stratigraphy of Holocene sediment cores from two Antarctic lakes (Mondsee, Tiefersee; 62° 10 S/58° 50 W) of King George Island was investigated. The diatom assemblages were dominated by cosmopolitan species. The flora was composed of three main components: 1) taxa of submersed bryophytic habitats, which also occur in the bryophilic diatom flora of southern South America; 2) species of various terrestrial habitats, including some specific subantarctic taxa; 3) species distributed in coastal inland waters influenced by sea-spray.Changes in sediment pattern and diatom species composition seemed to reflect climatic changes. At least three different core sections were distinguished in both lakes: Two sections rich in mosses occur between approx. 7000–4700 B.P. and from 3200 B.P. to present, in general resembling present day conditions. In between is a section of high allochthonous content with generally low diatom concentrations and rising percentages of aerophilic, halophilic and alkaliphilic diatoms. An increase of melt water discharge, possible sea-spray influence, and lake- level fluctuations are discussed.Three new taxa are described: Achnanthes metakryophila nov. spec., Achnanthes renei nov. spec., Navicula australomediocris nov. spec. The taxonomy of selected taxa is discussed.     

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

薛耀松,沈炎彬,卓二军ＰｅｔｒｏｌｏｇｉｃａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｔｈｅｓｅｄｉｍｅｎｔａｒｙｖｏｌｃａｎｉｃｌａｓｔｉｃｒｏｃｋｓｏｆｔｈｅＦｏｓｓｉｌＨｉｌｌＦｏｒｍａｔｉｏｎ（ｅｏｃｅｎｅ）ｉｎＫｉｎｇＧｅｏｒｇｅＩｓｌａｎｄ,Ｗ...     

Characteristics of the mineral phase constituents of lacustrine deposits from the Fildes Peninsula of King George Island, Antarctica and their environmental implication

ＣｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｔｈｅｍｉｎｅｒａｌｐｈａｓｅｃｏｎｓｔｉｔｕｅｎｔｓｏｆｌａｃｕｓｔｒｉｎｅｄｅｐｏｓｉｔｓｆｒｏｍｔｈｅＦｉｌｄｅｓＰｅｎｉｎｓｕｌａｏｆＫｉｎｇＧｅｏｒｇｅＩｓｌａｎｄ,Ａｎｔａｒｃｔｉｃａａｎｄｔｈｅｉｒｅｎ...     

The elemental geochemical characteristics of Late Quaternary rock core from Yanwo Lake in the Great Wall Station area， King George Island， Southwest Antarctica

ＴｈｅｅｌｅｍｅｎｔａｌｇｅｏｃｈｅｍｉｃａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆＬａｔｅＱｕａｔｅｒｎａｒｙｒｏｃｋｃｏｒｅｆｒｏｍＹａｎｗｏＬａｋｅｉｎｔｈｅＧｒｅａｔＷａｌｌＳｔａｔｉｏｎａｒｅａ，ＫｉｎｇＧｅｏｒｇｅＩｓｌａｎｄ，Ｓｏｕｔｈｗｅ...