GeoMaud expedition
The GeoMaud expedition was carried out by the Federal Institute for Geosciences and Natural Resources to the central Dronning Maud Land with international participation. The geological and geophysical work concentrated on an area of the Dronning Maud Land, which has not been visited since the early 1960s, which lies at the interface between East and West Gondwana and thus for the understanding of the mountain formations during the formation of supercontinents and the reconstruction of Gondwana and the older supercontinent Rodinia plays an important role.
The expedition began in Cape Town on November 10, 1995 and ended there on March 18, 1996.
Background and planning
The GeoMaud expedition to the central Dronning Maud Land (essentially the mountain ranges of the Wohlthat massif and the Orvinfjella ) was an initiative of the Academy of Sciences of the GDR in the late 1980s and was originally planned for the southern summer of 1990/91. The designated scientific staff was based in the polar department of the Central Institute for Earth Physics in Potsdam . As part of the 4th Antarctic expedition of the GDR , geological work was to be carried out in the Wohlthatmassiv , starting from the Georg Forster station in the Schirmacher Oasis . As a result of German reunification and the associated changes in the research institutions in the former GDR, an expedition with a greatly reduced program under the logistical direction of the Alfred Wegener Institute could only take place in the following summer of 1991/92. With the takeover of some scientists from the polar department of the ZIPE into the BGR , the idea of a large-scale expedition to the little-explored regions of the central Dronning Maud Land was promoted there from 1991.
Scientific questions
The target region was visited in the early 1960s as part of Soviet expeditions. The focus here was primarily on petrological investigations and the radiometric age investigations, which were still in the early stages of their development , but only provided evidence of a heating of the crust as a result of extensive magmatism 500 million years ago. On the basis of comparative studies with similarly structured crusts on other continents, the Soviet researchers assumed a possibly archaic crustal age. Since the research in the 1960s had been carried out with airplanes, the investigations were also limited to the area around suitable landing strips.
For the new investigations, a geological and geophysical new recording as extensive as possible was planned, which should help to clarify a number of questions:
- Age and structure of the earth's crust in this sector of Antarctica,
- the further course of the approx. 1 billion year old mountain belt in the region, which is known from earlier work from the western Dronning Maud Land,
- Effects of the metamorphic overprinting of the crust about 500 million years ago during the collision of western and eastern Gondwana, as well as the prevailing pressure and temperature conditions,
- Magmatism related to ore formation 500 million years ago,
- Paleomagnetic studies to determine the drift of the Antarctic plate ,
- Magmatism in connection with the disintegration of Gondwana , which began in the Jurassic ,
- History of glaciation in the Cenozoic ,
- Current ice cover and topography of the bedrock below the inland ice .
execution
The GeoMaud expedition was carried out by BGR in collaboration with the Alfred Wegener Institute (AWI) , as well as German and foreign research institutes. In addition to a land group led by Hans-Jürgen Paech, the GeoMaud expedition also consisted of a marine group led by Karl Hinz , which carried out seismic studies in the Southern Ocean with the help of the ships POLAR QUEEN and NEMCHINOV .
The country group consisted of 23 scientists from almost all geoscientific disciplines who were recruited from the BGR, the AWI, VNIIOkeanologiya St. Petersburg and the universities of Aachen , Bremen , Dresden , Freiburg , Münster , Siena and Turin . They were supported by 18 functional staff (helicopter crews, radio operators, mountain guides, etc.) from Australia, Germany, New Zealand and Austria. A photogrammetric program for the preparation of EPICA (European Polar Ice Coring in Antarctica) and the disposal of the former GDR station Georg-Forster in the Schirmacher-Oase by the AWI were also logistically closely interlinked with GeoMaud , some of the staff also traveled with the Expedition ship on and off.
The expedition left Cape Town on November 10, 1995 on board the POLAR QUEEN and reached Cape Ostry on November 19. The unloading and the establishment of a base camp in the Schirmacher oasis near the Russian Novolasarewskaya station lasted until November 24th . After a few exploratory flights, the construction of a tent camp in the Dallmann Mountains began on December 4th, which accommodated the geology group of around 20 people. The geophysics group, which mainly operated with helicopters, remained in the base camp. Two helicopters and two snowmobiles were available for transport in the area . Small working groups of two to four people worked in the field and produced geological maps on a scale of 1: 50,000. Satellite camps were set up in particularly interesting regions, allowing individual teams to conduct detailed investigations. On January 16, 1996, the main camp was relocated around 90 km further east to the Petermann range, from where the second section of the field work in the Alexander von Humboldt Mountains and in the Wohlthat massif was carried out. On February 25, the main camp and the remaining satellite camps were disbanded and the expedition gathered again at the base camp. Geological field work in the Schirmacher Oasis and the Nunataks to the south could still be carried out until March 1st. From March 2 to 9, 1996, the expedition cargo was loaded, transported by land to Cape Ostry and loaded onto the POLAR QUEEN. On March 10th, POLAR QUEEN cast off and reached Cape Town after an eight-day journey.
List of participating scientists
| Surname | institution | Research area |
| Hans-Jürgen Paech | Federal Institute for Geosciences and Natural Resources (BGR) | Expedition leader |
| Detlef Damaske | BGR | deputy expedition leader and aeromagnetics |
| Wilfried Bauer | RWTH Aachen | Structural geology and structure science |
| Heinz Bennat | Institute for Applied Geodesy | Aerial photography |
| Fabrizio Colombo | University of Siena | Petrology |
| Volkmar Damm | BGR | Radioglaciology |
| Manfred Degutsch | University of Munster | Seismics |
| Georg Delisle | BGR | Geothermal energy |
| Günther Druivenga | NLfB-GGA | Gravimetry |
| Dieter Eisenburger | BGR | Radioglaciology |
| Friedhelm Henjes art | BGR | geochronology |
| Wolf-Dieter Hermichen | Alfred Wegener Institute (AWI) | glaciology |
| Joachim Jacobs | University of Bremen | Structural Geology and Fission Track Dating |
| Gregor Markl | University of Freiburg | Petrology |
| Evgeniy Mikhalski | All-Russian Institute of Oceanology, St. Petersburg | Petrology |
| Martin Olesch | University of Bremen | Petrology |
| James Pearl | University of Dresden | geodesy |
| Sandra Piazolo | University of Freiburg | Petrology |
| Gernot Reitmayer | BGR | Gravimetry |
| Norbert Roland | BGR | geochemistry |
| Daniel Steinhage | University of Munster | Seismics |
| Franco Talarico | University of Turin | Petrology |
| Uli wall | AWI | glaciology |
Results
A new geological map on a scale of 1: 250,000 was created of the ice-free mountain ranges examined and samples were taken for laboratory tests. In addition, 17,000 km of aeromagnetic airways, 10,000 km of airways for radar investigation of the ice thickness and measurements of the earth's gravity at 159 points were made. The results of the investigations were published by 2005 and led to a new model for the development of the crust in this sector of Antarctica .
The rock series of the central Dronning Maud Land consist of gneisses and amphibolites , which are interpreted as the products of a volcanic island arc that existed in the Upper Mesoproterozoic . After its collision with the Kaapvaal Kraton , the first tectonic overprinting occurred , combined with an intensive rock metamorphosis. After a long period of erosion penetrated about 600 million years ago at the end of the Neoproterozoic anorthosite - plutons into the crust one. The mountain ranges received their current fold structure between 570 and 520 million years ago during the collision of East and West Gondwana. Large plutons with a syenitic and granitic composition penetrated the earth's crust, which was thickened by folds and thrusts . These plutons make up more than 20% of the exposed rock surface today.
After the formation of this mountain range, which continued in what is now East Africa, there was a long-lasting phase of erosion and leveling. The supercontinent Gondwana began to break up around 180 million years ago, basalt melts penetrated into fracture zones in the crust and solidified as ducts. Since then, the crust has also been uplifted by an average of 1 mm per year and the formation of today's relief began.
literature
- Karl Hinz : Expedition activity of the Federal Institute for Geosciences and Raw Materials in the Antarctic, 1995/96 . In: Polar Research . tape 64 , 1996, pp. 137–139 ( awi.de [PDF; 392 kB ]).
- Hans-Jürgen Paech: The BGR GeoMaud expedition . In: News of the German Geological Society . tape 57 , 1996, pp. 44-49 .
- Hans-Jürgen Paech, Jürgen Kothe: Logistics of the 1995/96 GeoMaud Expedition to Central Dronning Maud Land, East Antarctica . In: Geological Yearbook . B 97, 2005, p. 289-299 .
- Hans-Jürgen Paech: Present knowledge of the Geology of Central Dronning Maud Land, East Antarctica: Main Results of the 1995/96 GeoMaud Expedition . In: Geological Yearbook . B 97, 2005, p. 289-299 .
Individual evidence
- ↑ H.-U. Wetzel, K. Hahne, J. Belajev & E. Mikhalsky (1994): Geological and geochemical investigations in the Humboldt Mountains / Central Dronning Maud Land . Polar Research Reports 152, pp. 230-239, ISSN 0176-5027
- ^ MG Ravich, DS Soloviev: Geologiya i petrologiya central'noy chasti gor Zemli Korolevy . Nedra, Leningrad 1966, p. 1-290 .
Web links
- BGR project website , accessed on October 15, 2013