ALBERT

Description: The Antarctic Roadmap Challenges (ARC) project identified critical requirements to deliver high priority Antarctic research in the 21st century. The ARC project addressed the challenges of enabling technologies, facilitating access, providing logistics and infrastructure, and capitalizing on international co-operation. Technological requirements include: i) innovative automated in situ observing systems, sensors and interoperable platforms (including power demands), ii) realistic and holistic numerical models, iii) enhanced remote sensing and sensors, iv) expanded sample collection and retrieval technologies, and v) greater cyber-infrastructure to process ‘big data’ collection, transmission and analyses while promoting data accessibility. These technologies must be widely available, performance and reliability must be improved and technologies used elsewhere must be applied to the Antarctic. Considerable Antarctic research is field-based, making access to vital geographical targets essential. Future research will require continent- and ocean-wide environmentally responsible access to coastal and interior Antarctica and the Southern Ocean. Year-round access is indispensable. The cost of future Antarctic science is great but there are opportunities for all to participate commensurate with national resources, expertise and interests. The scope of future Antarctic research will necessitate enhanced and inventive interdisciplinary and international collaborations. The full promise of Antarctic science will only be realized if nations act together.

Description: IntroductionThe evolution of Antarctica and the Antarctic Ocean is vital to understanding the growth and breakup of super continent Gondwana. The reconstruction models of Gondwana have been established by many authors using geophysical data set as well as geological data (e.g. Norton and Sclater, 1978). The area around Syowa Station, the Japanese Antarctic wintering Station in Lützow- Holm Bay, is considered to be a junction of Africa, India, Madagascar, and Antarctic continents from the reconstruction models of Gondwana. Therefore this area is a key to investigate the formation and fragmentation of Gondwana. However, the tectonic evolution is still speculative because geological evidence is limited to a few isolated outcrops and the coverage with geophysical surveys in this area is poor.Joint Japanese-German airborne geophysical surveys around Syowa Station had been conducted in January 2006 during the 47th Japanese Antarctic Research Expedition to reveal tectonic evolution of the area around Syowa Station. The observation lines are shown in Figure 1.Data The airborne geophysical surveys had been made along almost N-S observation lines with spacing of about 20 km. Ice radar measurements had been carried out onshore area and ice thickness data are obtained. Bed rock topography are estimated using RAMP surface elevation data set. Magnetic and gravity measurements had been conducted both onshore and offshore areas. Magnetic anomalies are determined after correcting diurnal geomagnetic variations at Syowa Station. Precise positions of the aircraft are determined using DGPS techniques and free-air gravity anomalies are also obtained. Those data are girded and plotted using GMT software (Wessel and Smith, 1998).ResultsThe results of bed rock topography, gravity and magnetic anomalies are shown in Figures 2, 3 and 4, respectively. Characteristic features possibly related to the tectonic evolution from the results are summarized as followings.. Large negative gravity anomalies are observed along the Shirase Glacier (A in Figure 3) and those almost correspond to deep bed rock topography. Two sets of positive and negative gravity anomalies are shown along ocean-continental transition (B in Figure 3). However, magnetic anomalies along ocean-continental transition indicate only one set. NW-SE trending positive magnetic anomalies are observed between 40°E and 43°E near Antarctic continental margin (A in Figure 4). Those almost correspond to the transitional zone from Amphibolite to Granulite faces in the Lützow-Holm Complex. NE-SW trending magnetic anomalies in offshore area possibly indicate magnetic anomaly lineations (B in Figure 4). Positive magnetic anomalies surrounded by negative ones are observed around Cape Hinode (C in Figure 4). DiscussionLarge negative gravity anomalies and deep bed topography along the Shirase Glacier (A in Figure 4) possibly indicate major geological boundaries. It has been inferred that the peak metamorphic grade of the Lützow-Holm Complex progressively increases in a southwestern direction from amphibolite-facies to granulite-facies conditions and higher metamorphic grade are observed near the Shirase Glacier (Hiroi et al., 1983). Therefore large negative gravity anomalies and deep bed topography along the Shirase Glacier most likely delineate southwestern boundary of the Lützow-Holm Complex.Characteristic magnetic anomaly features around Cape Hinode (C in Figure 5) may indicate an allochthonous unit in the Lützow-Holm Complex. The main orogenic activities of the Lützow-Holm Complex took place during the Latest Proterozoic ro Early Paleozoic times. However, older rocks around 1000 Ma were documented at Cape Hinode within the Lützow-Holm Complex (Shiraishi et al., 1994). Magnetic anomaly data will provide new constraints for constructing tectonic evolution model in this area.NE-SW trending magnetic anomalies (B in Figure 5) possibly represent M sequence magnetic anomaly lineations. ENE-WSW and E-W magnetic anomaly lineation trends, possibly belonging to the Mesozoic magnetic anomaly lineation sequence, accompanied by the NW-SE and NNW-SSE trending fracture zones are deduced from vector magnetic anomalies just seaward of the continental slope of Antarctica to the east of Gunnerus Ridge (Nogi et al. 1996). NE-SW trending magnetic anomalies show similar strikes of magnetic anomalies from vector magnetic anomalies. Two sets of positive and negative gravity along ocean-continental transition (B in Figure 4) possibly reflect initial breakup conditions of Gondwana. Magnetic anomalies along ocean-continental transition do not show two sets of positive and negative magnetic anomalies. However, possible magnetic anomaly lineation trends in this area are almost parallel to the trends of gravity anomalies along ocean-continental transition and those imply that the direction of initial extension are normal to present coast line of Antarctica in this area. Two sets of positive and negative gravity along ocean-continental transition may suggest initial extension of Gondwana breakup.ConclusionsThe outline of ice thickness, bed rock topography, gravity and magnetic anomaly results in the area around Syowa Station are shown. Characteristic features from the results are indicated and discussed. These results provide new constraints on the tectonic evolution in the area a junction of Africa, India, Madagascar, and Antarctic continents of Gondwana. Further data analysis are carrying out and detailed discussion will be made based on those results.

Description: Electron microprobe (EMP) dating on monazite in granulite-facies rocks from Forefinger Point,East Antarctica, yielded dominant ages of ~500 Ma on matrix monazites.They are associated with secondary cordierite, biotite and sapphirine, formed during nearly isothermal decompression after the high P-T assemblages involving garnet, orthopyroxene and sillimanite. Older ages around 750 1 000 Ma are detected in monazite cores and in monazite inclusions in garnet porphyroblast. Combining the available age data and the reaction textures, it becomes evident that the Forefinger Point granulites have been overprinted by a granulite-facies decompressional event of Pan-African age. Moreover, EMP monazite dating imply that the Forefinger Point granulites have experienced at least two stages of metamorphic evolution.

Description: The area around Syowa Station, the Japanese Antarctic wintering Station in Lützow-Holm Bay, is a key area to investigate the formation of Gondwana, because this area is considered to be a junction of Africa, India, Madagascar, and Antarctic continents from the reconstruction model of Gondwana. However, the tectonic evolution is still speculative because geological evidence is limited to a few isolated outcrops and the coverage with geophysical surveys in this area is poor. Joint Japanese-German airborne geophysical surveys around Syowa Station had been conducted in January 2006 during the 47th Japanese Antarctic Research Expedition to reveal the tectonic evolution related to Gondwana formation and breakup in this area. Ice radar, magnetic, and gravity data are obtained using the AWI owned, Dornier aircraft (Polar-2). The airborne geophysical surveys had been made along almost N-S observation lines with spacing of about 20 km.Several characteristic features possibly related to the tectonic evolution of Gondwana are inferred from magnetic and gravity anomaly maps as well as bedrock topography. Large negative gravity anomalies are observed along the Shirase Glacier and those almost correspond to deep bed rock topography. This structure most likely delineate southwestern boundary of the Lützow-Holm Complex. Northeastern boundary of the Lützow-Holm Complex is also deduced from magnetic and gravity anomalies. Moreover, Lützow-Holm Complex seems to be divided into three segments by the boundaries with almost ENE-WSW strike. These structures may reflect tectonic movements of the post collision. Positive magnetic anomalies surrounded by negative ones are also observed around Cape Hinode within the Lützow-Holm Complex. These data will provide new constraints for constructing tectonic evolution model in this area.

Description: The Alfred Wegener Institute for Polar and Marine Research (AWI) operates since 1985 ski equipped aircraft (Dornier 228/101) for scientific and logistic purposes in the Arctic and the Antarctic. The aircraft can be equipped with many different instruments for geophysical measurements as well as for investigations of the Earths atmosphere. In austral summer 2005/06 the long and fruitful cooperation with the National Intstitute for Polar Research (NIPR) Tokyo has been continued by conducting the first season for the joined interdisciplinary research programme ANTSYO in east Dronning Maud Land, near the Japanese wintering base Syowa. This first season was dedicated to geophsysics, mapping ice thicknesses, magnetics and gravity covering Shirasebeen and its dainage baisin as well as the adjacent sea for the subprogrammes WEGAS and DISTINCT. The next survey is dedicated to atmospheric sciencesThe mass balance of Antarctica varies a lot across the whole continent. While some areas show evidence of a clear deficit in mass balance, for instance the Antarctic Peninsula, the difference between accumulation and ablation in other areas seems to be small and even the sign is not evident. While ice thickness and surface velocities can be determined by means of remote sensing, radio-echo sounding and satellite picture interferometry, accumulation and ablation have to be measured in-situ using snow pits, firn/ice cores, and depth sounders under ice shelves or in ice sheets. Remote sensing techniques can be easily applied for large areas while in-situ measurements will always be restricted to isolated point measurements and therefore are of limited areal density.In our contibution we will focus on the mass flux of Shirasebreen determined from recent data analysis of our radio-echo sounding flight and satellite picture interferometry. A detailed ice thickness map, covering more than 160000 km2 of the drainage baisin of Shirasebreen accomplish the presentation.

Description: The evolution of Antarctica and the Antarctic Ocean is vital to understanding the growth and breakup of super continent Gondwana. The area around Syowa Station, the Japanese Antarctic wintering Station in L_tzow-Holm Bay, is considered to be a junction of Africa, India, Madagascar, and Antarctic continents from the reconstruction model of Gondwana. Therefore this area is a key to investigate the formation and fragmentation of Gondwana. However, the tectonic evolution is still speculative because geological evidence is limited to a few isolated outcrops and the coverage with geophysical surveys in this area is poor. To reveal the tectonic evolution related to Gondwana formation and breakup in this area, joint Japanese-German airborne geophysical surveys around Syowa Station had been conducted in January 2006 during the 47th Japanese Antarctic Research Expedition. Ice radar, magnetic, and gravity data are obtained onshore and offshore areas using the AWI owned Polar2, a fixed wing Dornier aircraft (Do228-101) on skis. We present preliminary results of magnetic, gravity, and ice thickness (bed rock topography) measurements around Syowa Station obtained by the airborne geophysical survey 2006 and discuss the tectonic evolution in this area.

Description: Antarctic and Southern Ocean science is vital to understanding natural variability, the processes that govern global change and the role of humans in the Earth and climate system. The potential for new knowledge to be gained from future Antarctic science is substantial. Therefore, the international Antarctic community came together to ‘scan the horizon’ to identify the highest priority scientific questions that researchers should aspire to answer in the next two decades and beyond. Wide consultation was a fundamental principle for the development of a collective, international view of the most important future directions in Antarctic science. From the many possibilities, the horizon scan identified 80 key scientific questions through structured debate, discussion, revision and voting. Questions were clustered into seven topics: i)Antarctic atmosphere and global connections, ii) Southern Ocean and sea ice in a warming world, iii) ice sheet and sea level, iv) the dynamic Earth, v) life on the precipice, vi) near-Earth space and beyond, and vii) human presence in Antarctica. Answering the questions identified by the horizon scan will require innovative experimental designs, novel applications of technology, invention of next-generation field and laboratory approaches, and expanded observing systems and networks. Unbiased, non-contaminating procedures will be required to retrieve the requisite air, biota, sediment, rock, ice and water samples. Sustained year-round access toAntarctica and the Southern Ocean will be essential to increase winter-time measurements. Improved models are needed that represent Antarctica and the Southern Ocean in the Earth System, and provide predictions at spatial and temporal resolutions useful for decision making. A co-ordinated portfolio of cross-disciplinary science, based on new models of international collaboration, will be essential as no scientist, programme or nation can realize these aspirations alone.