Summertime Surface N2O Concentration Observed on Fildes Peninsula Antarctica:Correlation with Total Atmospheric O3 and Solar Activity

Three-year summertime surface atmospheric N_2O concentrations were observed for the first time on the Fildes Peninsula, maritime Antarctica, and the relationships among the N2O concentration, total atmospheric O3 amount, and sunspot number were analyzed. Solar activity had an important effect on surface N2O concentration and total O3 amount, and increases of sunspot number were followed by decreases in the N2O concentration and total O3 amount. A corresponding relationship exists between the N2O concentration and total atmospheric O3, and ozone destruction was preceded by N2O reduction. We propose that the extended solar activity in the Antarctic summer reduces the stratospheric N2O by converting it into NOx, increases the diffusion of N2O from the troposphere to the stratosphere, decreases the surface atmospheric N2O, and depletes O3 via the chemical reaction between O3 and NOx. Our observation results are consistent with the theory of solar activity regarding the formation of the Antarctic O3 hole.

GROUND TEMPERATURE AND ROCK THERMOPHYSICAL PROPERTIES IN FILDES PENINSULA

During 1985-1986, 1986-1987, and 1988-1989 expeditions on Fildes Peninsula the ground temperature was measured. A total number of 218 ground temperature data were obtained. The thermal conductivity measurements were made on 121 rock samples collected during expedition. This article gives a brief analysis and summarization of these data.

COASTAL PHENOMENA AND ISOSTATIC UPLIFT AROUND FILDES PENINSULA OF KING GEORGE ISLAND, SOUTH SHETLAND ISLANDS, ANTARCTICA

After a field work on recently raised coastal features in South Shetland Islands, we conclude that there are three kinds of recent coastal features, i. e, fragmental coast, rock coast, and ice cliff coast. The processes and forms of the fragmental cost formed by wave action with floating ice are studied. Systematic study of the raised coasts enables us to distinguish two groups of the coasts by an elevation of 20m a. s. 1. The raised coasts above 20m a. s. 1. belong to older group and those below 20m a. s. 1. belong to younger group. Mean uplift rate of coast in this area is 6. 7 mm/a.

Human impacts on the terrestrial ecosystem of Fildes Peninsula of King George Island, Antarctica

Antarctic environment has valuable baseline information for understanding the global change. The objectives of this study were to investigate the impacts of human activities on Antarctic terrestrial ecosystem. Based on the investigation results and the sampling analysis of the environment of Fildes Peninsula, King George Island, Antarctica, it was shown that there are some artificial radioactive elements—? ? 137 Cs in Antarctic environment: the radioactivity of 137 Cs in the surface soil, the surface moss, the fruticose lichen and the crustaceous lichen are 6 00—14 80, 25 07, 29 04 and 58 07 Bq/kg separately; i.e. the sequence of 137 Cs specific activity is as follows: crustaceous lichen>fruticose lichen>surface moss>surface soil, which demonstrates that the crustaceous lichen is one of the most sensitive monitor ways for the effect of the long term diffusion of 137 Cs. The impacts of the scientific research activities on the partial ecosystem of Fildes Peninsula include: the changes of the landscape and the soil material have made a strong freezing thawing process, which decreases the stability of the ground surface, causes the degradation of the vegetation in the some small areas; some small lakes, runoff and lichens in middle areas of Fildes Peninsula have been affected by the wastes of the stations, in the surrounding areas of the expedition stations, the concentration of Cr, Cu, Ni, Pb and Zn in the lichen and the water are higher than that of the contrasting area. Fildes Peninsula is one of the most crowded areas of expedition stations, at some extent, the environment and terrestrial ecosystem have been affected by the human activities. The conservation of the environment and ecosystem should be an important aspect of Antarctic environmental sciences.

The Characteristics and Mechanism of Island-Arc Volcanism on the Central and Southern Fildes Peninsula, King George Island, Antarctica

The volcanic rock series on the Fildes Peninsula is the product of the later subduction of the Pacific platebeneath the Antarctic plate. It consists mainly of basalt, basaltic andesite and andesite with minor dacite. Itsisotopic ages range from 64.6±1 to 43±2 Ma, belonging to Palaeocene to Eocene. Volcanism in the area maybe divided into two phases. The contents of major oxides, rare earth elements (REE) and trace elements in vol-canic rocks formed in different phases show regular changes, which are mainly related to the rock associationsof these phases. Isotope geochemical studies indicate that the primitive magma in the area originating by par-tial melting in the upper mantle underwent fractional crystallization and ascended to the high-level (shallow)magma chamber. Before eruption the primitive basalt-andesitic magma was subjected to differentiation in thehigh-level magma chamber, forming zones of derivative magmas of different compositions. In various phasesmagma-conducting faults experienced periodic extension and cut through various derivative magma zones indifferent parts of the peninsula, leading to the eruption of magmas of different compositions on the surface andthe formation of volcanic rock associations of corresponding compositions.

Eco-environmental spatial characteristics of Fildes Peninsula based on TuPu models

This study applies a TuPu analysis to investigate ecological and environmental aspects of an Antarctic ice-free area, using Fildes Peninsula as an example. The TuPu unit was determined using a vector-grid mixed data model. Information from the eco-environment elements was effectively extracted, and was generalized into different classes by means of data mining technol- ogy. A series of single-factor thematic information TuPu models, such as topography, soil, animal and vegetation, and human activities for Fildes Peninsula were built in this study. The topography TuPu model contained information on elevation and slope. The soil TuPu model involved soil development stages and soil thickness information. The animal and vegetation TuPu model contained the distribution of animals, plant types, lichen cover and lichen height. The human activities TuPu model included popu- lation density and human disturbance index information. The landscape comprehensive information TuPu model of Fildes Penin- sula also was established, and contains twenty-nine landscape units and twelve types of combined environments. The study quan- titatively revealed the spatial morphology and correlation of the regional eco-environment based on the analysis of these TuPu models. From these models, we can draw the conclusion that there is a regular differentiation of eco-environment from the coastal bands to the central hills in Fildes Peninsula, and that the eco-environment condition of the eastern coasts is different from that of the western coasts. The eco-environmental spatial variation also differs greatly from north to south. Based on analysis of spatial correlation, the vegetation in Fildes Peninsula has the greatest correlation with human activity, and has a certain correlation with topography and soil. This research may provide a new technical approach and scientific basis for the in-depth study of Antarctic eco-environments.

Preliminary evidence for 17 coastal terraces on Fildes Peninsula, King George Island, Antarctica

This study confirms the presence of 17 coastal terraces on Fildes Peninsula, Antarctica based on field observations and grain size analysis. The terraces formed by isostatic uplift during climate warming and glacier melting, and each level corresponds to a relatively stable period of climate. The grain size characteristics indicate an overlapping sedimentary origin for the sediments on the coastal terraces. The consistency of regional sea level rise, climate change, and glacial area suggest the presence of similar coastal terraces on King George Island since 18.0 ka.

GEOLOGY OF FILDES PENINSULA, KING GEORGE ISLAND, WEST ANTARCTICA——A Study on the Stratigraphy and Volcanism

On the basis of the geological mapping, isotopic choronoogcal and petrological evidences, the authors suggested that the early Tertiary volcanic strata in the Fildes Peninsula could be divided into two formations and four members. The erupted centers in the peninsula were gradualy migrating from the western coast to the eastern and the subvolcanic intrusives were regularly distributed along a series of NWW-SEE trending faults. All of these were basically formed in two stages of volcanic activities from Paleocene to Eocene.

PALEOMAGNETISM OF THE LATE CRETACEOUS AND EARLY TERTIARY ROCKS FROM FILDES PENINSULA,WEST ANTARCTICA, AND ITS GEOTECTONIC SIGNIFICANCE

The paleomagnetis m of 109 oriented samples collected from drill cores through 5 rock units of Late Cretaceous and Early Tertiary on Fildes Peninsula were systematically studied-According to the study, the paleomagnetic pole position of this area is different from the position of Australia during the 55-45 Ma period. This means that when the break - up of the Gondwanaland at 55 - 45 Ma ago, Australia was separated from the Gondwanaland, drifting southward 20°-30°Lat. and rotating 70°-80°westward and then gradually arriving at recent position . The paleolatitudinal data indicate that it is not impossible that the area studied was covered with land glacier at that time. The apparent polar wander path of Antarctica through the geological time are also roughly worked out.

SYSTEMATIC COVARIATION OF SR, BA, CA ELEMENTS IN CENOZOIC VOLCANIC ROCKS ON THE FILDES PENINSULA, WEST ANTARCTICA, AND ITS RELATION TO PEIROGENESIS

Cenozoic volcanic rocks in the Fildes Peninsula are composed of High-Al basalt, basaltfc andesite, andesite, and dacite belonging to a calc-alkaline volcanic series with low-K and high-Al characteristics. Using a new indicator, the Sr / Ca-Ba / Ca, systematics proposed by Onuma (1980, 1981) and Sr, Ba, Ca concentrations in volcanic lavas and subvolcanic rocks, the authors find that the high-Al basaltic volcanic rocks either in volcanic strata or in subvolcanic intrusives were formed from a primary magma, in different stages through the fractional crystallization of clinopyro-xene(Cpx)and plagioclase (P1) in the process of magmatic evolution, resulting in the formation of basaltic-andesitic, andesitic and dacitic rocks.

Three species of bryophytes from the Fildes Peninsula of Antarctica under the observation of SEM

This article is to describe the characteristics of morphological structure of sporogona of three bryophytes observed under the SEM from the Fildes Peninsula, Antarctica, which has riched research information of bryophyte study of the area.

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

ased 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.

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

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.

Deep electrical conductivity structure in the Great Wall Station area， Fildes Peninsula， West Antarctica

MT measured in Great Wall Station area shows that the electrical conductivity major axis of the Wind Valley Fault is 110°NE and the crustal thickness in the Fildes Peninsula is about 22. 3 km. The crust contains four main resistivity layers with their thicknesses being 1. 3 km, 6. 7 km, 1. 2 km and 13.1 km respectively. The upper crustal thickness is 9. 2 km and the lower crustal thickness is 13. 1 km.

ISO TOPIC AGE AND STRATIGRAPHYCAL CORRELATION OF VOLCANIC ROCKS IN FINDES PENINSULA, KING GEORGE ISLAND

The ages of volcanic rocks from the Fildes Peninsula of King George Island, West Antarctica, have been determined with K-Ar, 39 Ar -40Ar, Rb -Sr methods by the authors. The results show that:a. The volcanism on the Fildes Peninsula has been from later Paleocene to early Middle Miocene; b. The formation time of the volcanic rocks of Jasper Hill Member belongs to later Paleocene becarse of the isotope age being 54Ma and 55Ma determined with Rb -Sr and 39 Ar -40Ar methods, respectively, c. The volcanic rocks of Agate Beach Member are the products of the volcanic activities during Early Eocene according to K -Ar isochron(45 -50Ma); d. The geological age of fossil Hill member is about Middle Eocene to Early Oligocene; e. the formation time of Block Hill member is probably early Middle Miocene.These data combining with the geological adn palaeontological evidences strongly support to best understand the stratigraphical correlation adn reveal the volcanism in studied area.