New Paleomagnetic Data From Thurston Island: Implications for the Tectonics of West Antarctica and Weddell Sea Opening

Paleomagnetic data from three West Antarctic crustal blocks (Antarctic Peninsula (AP), Thurston Island-Eights Coast (TI), and the Ellsworth-Whitmore Mountains (EWM) indicate that there has been motion between the individual blocks and motion relative to East Antarctica during the Mesozoic. A Triassic paleomagnetic pole from the TI block (116°E, 61°S, A_95 = 19.4°, N = 3 VGPs) appears to indicate that the block has rotated ~90° relative to East Antarctica between 230 Ma and 110 Ma. Our previously reported Middle Jurassic paleomagnetic pole from the EWM block indicates that a 90° rotation relative to East Antarctica occurred sometime between the Cambrian and 175 Ma. We believe that the 90° counterclockwise EWM rotation occurred between ~220 Ma and 175 Ma related to the development of post-Gondwanide Orogeny shear zones. The motion of the AP, TI, and EWM blocks appears to be linked during the mid- to late Mesozoic to three major events in the evolution of the southern ocean basins. Opening in the Mozambique-Somali-Weddell Sea basins may have produced major counterclockwise rotation of the TI block with respect to East Antarctica between the Jurassic and Early Cretaceous based on new Late Jurassic (145°E, 64.5°S, A_95 = 7°,N = 5 VGPs) poles. We believe that the TI rotation, as well as deformation in the southern AP block, was caused by collision and shearing of the EWM block against the other two as the EWM block moved southward with East Antarctica. An Early Cretaceous paleomagnetic pole (232°E, 49°S, A_95 = 7.9°, N = 5 VGPs) from the TI block requires that between the Early and mid- Cretaceous there was clockwise rotation, with respect to East Antarctica, of the AP-TI-EWM blocks (an entity we call Weddellia). A change in the opening history of the Weddell Sea basin caused by initiation of spreading in the South Atlantic ocean basin at ~130 Ma probably started Weddellia's clockwise rotation. Two new ~110 and ~90 Ma poles from the TI block (210°E, 73°S, A_95 = 7.6°,N = 7 VGPs and 161°E, 81°S, A_95= 3.9°,N = 18 VGPs, respectively) are similar to equivalent age poles from the AP block and East Antarctica and indicate that Weddellia was at or near its present-day position with respect to East Antarctica by ~110 Ma. This corresponds to a time of major plate reorganization in the South Atlantic and southeast Indian Oceans. Based on both the new TI paleomagnetic data and previously reported data from Marie Byrd Land (MBL), dextral shearing would be expected to have occurred between MBL and Weddellia since the mid-Cretaceous. Pine Island Bay, the area between the TI and MBL blocks, marks a fundamental and complex tectonic boundary in West Antarctica that we propose has largely been a zone of transcurrent shearing

Raman spectra of olivine measured in different planetary environments

Missions to bodies of our solar system are coming up and imply new instrumentation to be applied remotely and in situ. In ESA’s ExoMars mission the Raman Laser Spectrometer (RLS) will identify minerals and organic compounds in Martian surface rocks and soils. Here we present the results of a Raman study of different olivines with variable Fo and Fa contents. We chose olivine because it is a rock forming mineral and is found as an abundant mineral in Martian meteorites. We determined the Raman spectra in different environmental conditions that include vacuum, 8 mbar CO2 atmosphere and temperatures between room temperature and 10 K. These environmental conditions resemble those on asteroids as well as on Mars and Moon. Thus our study investigates the influence of these varying conditions on the position and band width of the Raman lines, which is to be known when such investigations are performed in future space missions

Observation of mesospheric air inside the arctic stratospheric polar vortex in early 2003

During several balloon flights inside the Arctic polar vortex in early 2003, unusual trace gas distributions were observed, which indicate a strong influence of mesospheric air in the stratosphere. The tuneable diode laser (TDL) instrument SPIRALE (Spectroscopie InFrarouge par Absorption de Lasers Embarqués) measured unusually high CO values (up to 600 ppb) on 27 January at about 30 km altitude. The cryosampler BONBON sampled air masses with very high molecular Hydrogen, extremely low SF6 and enhanced CO values on 6 March at about 25 km altitude. Finally, the MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) Fourier Transform Infra-Red (FTIR) spectrometer showed NOy values which are significantly higher than NOy* (the NOy derived from a correlation between N2O and NOy under undisturbed conditions), on 21 and 22 March in a layer centred at 22 km altitude. Thus, the mesospheric air seems to have been present in a layer descending from about 30 km in late January to 25 km altitude in early March and about 22 km altitude on 20 March. We present corroborating evidence from a model study using the KASIMA (KArlsruhe Simulation model of the Middle Atmosphere) model that also shows a layer of mesospheric air, which descended into the stratosphere in November and early December 2002, before the minor warming which occurred in late December 2002 lead to a descent of upper stratospheric air, cutting of a layer in which mesospheric air is present. This layer then descended inside the vortex over the course of the winter. The same feature is found in trajectory calculations, based on a large number of trajectories started in the vicinity of the observations on 6 March. Based on the difference between the mean age derived from SF6 (which has an irreversible mesospheric loss) and from CO2 (whose mesospheric loss is much smaller and reversible) we estimate that the fraction of mesospheric air in the layer observed on 6 March, must have been somewhere between 35% and 100%

Ellsworth-Whitmore Mountains Crustal Block, Western Antarctica: New paleomagnetic results and their tectonic significance

Preliminary paleomagnetic study of granitic and sedimentary rocks from the Ellsworth-Whitmore Mountains crustal block (EVH), Vest Antarctica, leads to the following conclusions: (1) The EVH has a paleogole for the Middle Jurassic located at 235°E, 41°S, (α₉₅ = 5.3, N = 8 sites) assuming that no widespread regional tilting has occurred since the magnetization measured was acquired. A Middle Jurassic paleolatitude of 47°S is indicated for the sites and precludes an original location for the EVH block south of the Antarctic Peninsula crustal block (AP). (2) This pole is not significantly different from the previously published Middle Jurassic paleopole obtained from rocks of the northern Antarctic Peninsula. The combined AP-EVH paleopole, compared to the Middle Jurassic mean paleopole obtained from igneous rocks of the Ferrar Supergroup in East Antarctica, suggests about 15° tectonic clockwise rotation of the AP and EVH. Since the AP and EVH poles coincide, these two crustal blocks may have moved as one unit since the Middle Jurassic. ( 3) The new data are compatible with two different Gondwanaland reconstructions. The first considers the AP and EVH as separate entities. The second is based on the movement of the AP and EVH as one block. For the Middle Jurassic, both reconstructions would locate the EVH west of Coats Land and south of the Falkland Plateau, with the adjacent AP located south of southernmost South America. (4) Enigmas concerning the structural trend and isolation of the thick Ellsworth Mountains Paleozoic succession persist

Rapid and High-Throughput Detection of Highly Pathogenic Bacteria by Ibis PLEX-ID Technology

In this manuscript, we describe the identification of highly pathogenic bacteria using an assay coupling biothreat group-specific PCR with electrospray ionization mass spectrometry (PCR/ESI-MS) run on an Ibis PLEX-ID high-throughput platform. The biothreat cluster assay identifies most of the potential bioterrorism-relevant microorganisms including Bacillus anthracis, Francisella tularensis, Yersinia pestis, Burkholderia mallei and pseudomallei, Brucella species, and Coxiella burnetii. DNA from 45 different reference materials with different formulations and different concentrations were chosen and sent to a service screening laboratory that uses the PCR/ESI-MS platform to provide a microbial identification service. The standard reference materials were produced out of a repository built up in the framework of the EU funded project “Establishment of Quality Assurances for Detection of Highly Pathogenic Bacteria of Potential Bioterrorism Risk” (EQADeBa). All samples were correctly identified at least to the genus level

Atlantic salmon cardiac primary cultures:An in vitro model to study viral host pathogen interactions and pathogenesis

Development of Salmon Cardiac Primary Cultures (SCPCs) from Atlantic salmon pre-hatch embryos and their application as in vitro model for cardiotropic viral infection research are described. Producing SCPCs requires plating of trypsin dissociated embryos with subsequent targeted harvest from 24h up to 3 weeks, of relevant tissues after visual identification. SCPCs are then transferred individually to chambered wells for culture in isolation, with incubation at 15-22°. SCPCs production efficiency was not influenced by embryo's origin (0.75/ farmed or wild embryo), but mildly influenced by embryonic developmental stage (0.3 decline between 380 and 445 accumulated thermal units), and strongly influenced by time of harvest post-plating (0.6 decline if harvested after 72 hours). Beating rate was not significantly influenced by temperature (15-22°) or age (2-4 weeks), but was significantly lower on SCPCs originated from farmed embryos with a disease resistant genotype (F = 5.3, p<0.05). Two distinct morphologies suggestive of an ex vivo embryonic heart and a de novo formation were observed sub-grossly, histologically, ultra-structurally and with confocal microscopy. Both types contained cells consistent with cardiomyocytes, endothelium, and fibroblasts. Ageing of SCPCs in culture was observed with increased auto fluorescence in live imaging, and as myelin figures and cellular degeneration ultra-structurally. The SCPCs model was challenged with cardiotropic viruses and both the viral load and the mx gene expression were measurable along time by qPCR. In summary, SCPCs represent a step forward in salmon cardiac disease research as an in vitro model that partially incorporates the functional complexity of the fish heart