Geochemistry and petrology of the ferropicrite dikes and associated rocks of Vestfjella, western Dronning Maud Land, Antarctica

This study provides insights into the composition and origin of ferropicrite dikes (FeOtot = 13 17 wt. %; MgO = 13 19 wt. %) and associated meimechite, picrite, picrobasalt, and basalt dikes found at Vestfjella, western Dronning Maud Land, Antarctica. The dikes crosscut Jurassic Karoo continental flood basalts (CFB) that were emplaced during the early stages of the breakup of the Gondwana supercontinent ~180 Ma ago. Selected samples (31 overall from at least eleven dikes) were analyzed for their mineral chemical, major element, trace element, and Sr, Nd, Pb, and Os isotopic compositions. The studied samples can be divided into two geochemically distinct types: (1) The depleted type (24 samples from at least nine dikes) is relatively depleted in the most incompatible elements and exhibits isotopic characteristics (e.g., initial εNd of +4.8 to +8.3 and initial 187Os/188Os of 0.1256 0.1277 at 180 Ma) similar to those of mid-ocean ridge basalts (MORB); (2) The enriched type (7 samples from at least two dikes) exhibits relatively enriched incompatible element and isotopic characteristics (e.g., initial εNd of +1.8 to +3.6 and initial 187Os/188Os of 0.1401 0.1425 at 180 Ma) similar to those of oceanic island basalts. Both magma types have escaped significant contamination by the continental crust. The depleted type is related to the main phase of Karoo magmatism and originated as highly magnesian (MgO up to 25 wt. %) partial melts at high temperatures (mantle potential temperature >1600 °C) and pressures (~5 6 GPa) from a sublithospheric, water-bearing, depleted peridotite mantle source. The enriched type sampled pyroxene-bearing heterogeneities that can be traced down to either recycled oceanic crust or melt-metasomatized portions of the sublithospheric or lithospheric mantle. The source of the depleted type represents a sublithospheric end-member source for many Karoo lavas and has subsequently been sampled by the MORBs of the Indian Ocean. These observations, together with the purported high temperatures, indicate that the Karoo CFBs were formed in an extensive melting episode caused mainly by internal heating of the upper mantle beneath the Gondwana supercontinent. My research supports the view that ferropicritic melts can be generated in several ways: the relative Fe-enrichment of mantle partial melts is most readily achieved by (1) relatively low degree of partial melting, (2) high pressure of partial melting, and (3) melting of enriched source components (e.g., pyroxenite and metasomatized peridotite). Ferropicritic whole-rock compositions could also result from accumulation, secondary alteration, and fractional crystallization, however, and caution is required when addressing the parental magma composition.

Policy analysis and integrated land use.

XVIII IUFRO World Congress, Ljubljana 1986.

Cost and effectiveness of legal mandates for the practice of forestry on private land.

XVIII IUFRO World Congress, Ljubljana 1986.

Deutschland, Deutschland über alles : Tysk föreningsverksamhet i Finland och Sverige 1910-1950

The voluntary associations dealt with in this dissertation were ethnic clubs and societies promoting the interests of German immigrants in Finland and Sweden. The associations were founded at the end of the 19th century as well as at the beginning of the 20th century during a time in which migration was high, the civil society grew rapidly and nationalism flourished. The work includes over 70 different associations in Finland and Sweden with a number of members ranging from ten to at most 2, 500. The largest and most important associations were situated in Helsinki and Stockholm where also most of the German immigrants lived. The main aim of this work is to explore to what extent and how the changes in government in Germany during 1910 to 1950 were reflected in the structures and participants, financial resources and meeting places, networks and activities of the German associations in Finland and Sweden. The study also deals with how a collective German national identity was created within the German associations. The period between 1910 and 1950 has been described by Hobsbawm as the apogee of nationalism. Nationalism and transnationalism are therefore key elements in the work. Additionally the research deals with theories about associations, networking and identity. The analysis is mostly based on minutes of meetings, descriptions of festivities, annual reports and historical outlines about the associations. Archival sources from the German legations, the German Foreign Office, and Finnish and Swedish officials such as the police and the Foreign Offices are also used. The study shows that the collective national identity in the associations during the Weimar Republic mostly went back to the time of the Wilhelmine Empire. It is argued that this fact, the cultural propaganda and the aims of the Weimar Republic to strengthen the contacts between Germany and the German associations abroad, and the role of the German legations and envoys finally helped the small groups of NSDAP to infiltrate, systematically coordinate and finally centralize the German associational life in Finland and Sweden. The Gleichschaltung did not go as smoothly as the party wanted, though. There was a small but consistent opposition that continued to exist in Finland until 1941 and in Sweden until 1945. The collective national identity was displayed much more in Sweden than in Finland, where the associations kept a lower profile. The reasons for the profile differences can be found in the smaller number of German immigrants in Finland and the greater German propaganda in Sweden, but also in the Finnish association act from 1919 and the changes in it during the 1920s and 1930s. Finally, the research shows how the loss of two world wars influenced the associations. It argues that 1918 made the German associations more vulnerable to influence from Germany, whereas 1945 brought the associational life back to where it once started as welfare, recreational and school associations.