Abstract top ↑
After three months of fieldwork, the scientists returned from northern Victoria Land with 12 tons of rock samples for petrographic, geochemical, radiometric, paleomagnetic, and paleontological studies. The results of the field work and the initial laboratory findings were presented in the first GANOVEX III volume which was published in 1984 (Geol. Jb., B 60).
In this second volume, more detailed geochemical, petrological and petrographical results are presented. In the high-grade Wilson Metamorphics of Thompson Spur, Daniels Range, migmatites were produced either by granitic intrusion, or by influx of a fluid phase along foliation planes.
Data are presented on geothermometry and mineral reactions in the contact-metamorphic aureole of the layered Tiger Gabbro which intrudes volcanic rocks of the Bowers Terrane at Spatulate Ridge.
New inforrnation is also presented on the tectonic setting of northern Victoria Land. The ultramafic lenses of the eastern Lanterman Range are interpreted as slivers of oceanic crust, scraped off during Paleozoic subduction or accretion processes.
In the Lanterman Range, folded Beacon sediments have been sandwiched between the basement rocks as a result of post-Jurassic thrusting and/or strike-slip movements, i.e. compressional forces in the tensional regime which gave rise to the asymmetric Rennick Graben. The formation of this graben is discussed and related to rifting processes in the Ross Sea.
Triassic plant fossils (e.g. Dicroidium odontopteroides) are described from the terrestrial Beacon sequence, as well as uppermost (?) Cambrian to Tremadocian conodonts which were found in the Robertson Bay Group at Handler Ridge. The most important work in this volume is the revised and considerably expanded "Geological map of North Victoria Land" at a scale of 1: 500000. The explanatory notes represent a summary of 30 years of geological rescarch in this region.
Several new geographical names appear on the map. These were proposed by members of the GANOVEX expeditions and have been officially approved by the "Ständiger Ausschuß für Geographische Namen" (Standing Com- mittee on Geographical Names) and the German national "Scientific Committee on Antarctic Research" (SCAR).